T cells can contribute to metastatic spreading in lung cancer. However, the contributions of T cell subpopulations to tumor spreading are not well understood. In this issue of the JCI, Salazar et al. explored Th9 and Th17 cells and the epithelial-mesenchymal transition in cell culture, lung tumor tissue, and mouse models. Th9 and Th17 cells were observed in lung cancer samples and promoted EMT to result in metastatic spreading. The cover image depicts a non–small cell lung tumor specimen showing epithelial cells (anti-cytokeratin, green), Th17 cells (labeled with anti-CD4, red; and anti-STAT3, magenta), Th9 cells (labeled with anti-CD4, red; and anti-PU.1, yellow), and their nuclei (blue).
Lucy Y. Ghoda, Steven T. Rosen, Larry W. Kwak
David T. Ting, Julius J.S. Knowles
Norman E. Sharpless
Mark Donowitz, Jerrold R. Turner, Alan S. Verkman, Nicholas Constantine Zachos
Maximilian F. Konig, Mike Powell, Verena Staedtke, Ren-Yuan Bai, David L. Thomas, Nicole Fischer, Sakibul Huq, Adham M. Khalafallah, Allison Koenecke, Ruoxuan Xiong, Brett Mensh, Nickolas Papadopoulos, Kenneth W. Kinzler, Bert Vogelstein, Joshua T. Vogelstein, Susan Athey, Shibin Zhou, Chetan Bettegowda
Barney S. Graham, Kizzmekia S. Corbett
Evelyne Bischof, Jeannette Wolfe, Sabra L. Klein
Cryptococcus neoformans is an opportunistic yeast that is present worldwide and interacts with various organisms. In humans, it is responsible for cryptococcosis, a deadly invasive fungal infection that represents around 220,000 cases per year worldwide. Starting from the natural history of the disease in humans, there is accumulating evidence on the capacity of this organism to enter dormancy. In response to the harsh host environment, the yeast is able to adapt dramatically and escape the vigilance of the host’s immune cells to survive. Indeed, the yeast exposed to the host takes on pleiotropic phenotypes, enabling the generation of populations in heterogeneous states, including dormancy, to eventually survive at low metabolic cost and revive in favorable conditions. The concept of dormancy has been validated in C. neoformans from both epidemiological and genotyping data, and more recently from the biological point of view with the characterization of dormancy through the description of viable but nonculturable cells.
Herpesviruses infect virtually all humans and establish lifelong latency and reactivate to infect other humans. Latency requires multiple functions: maintaining the herpesvirus genome in the nuclei of cells; partitioning the viral genome to daughter cells in dividing cells; avoiding recognition by the immune system by limiting protein expression; producing noncoding viral RNAs (including microRNAs) to suppress lytic gene expression or regulate cellular protein expression that could otherwise eliminate virus-infected cells; modulating the epigenetic state of the viral genome to regulate viral gene expression; and reactivating to infect other hosts. Licensed antivirals inhibit virus replication, but do not affect latency. Understanding of the mechanisms of latency is leading to novel approaches to destroy latently infected cells or inhibit reactivation from latency.
Jeffrey I. Cohen
Toxoplasma gondii is an incredibly successful parasite owing in part to its ability to persist within cells for the life of the host. Remarkably, at least 350 host species of T. gondii have been described to date, and it is estimated that 30% of the global human population is chronically infected. The importance of T. gondii in human health was made clear with the first reports of congenital toxoplasmosis in the 1940s. However, the AIDS crisis in the 1980s revealed the prevalence of chronic infection, as patients presented with reactivated chronic toxoplasmosis, underscoring the importance of an intact immune system for parasite control. In the last 40 years, there has been tremendous progress toward understanding the biology of T. gondii infection using rodent models, human cell experimental systems, and clinical data. However, there are still major holes in our understanding of T. gondii biology, including the genes controlling parasite development, the mechanisms of cell-intrinsic immunity to T. gondii in the brain and muscle, and the long-term effects of infection on host homeostasis. The need to better understand the biology of chronic infection is underscored by the recent rise in ocular disease associated with emerging haplotypes of T. gondii and our lack of effective treatments to sterilize chronic infection. This Review discusses the cell types and molecular mediators, both host and parasite, that facilitate persistent T. gondii infection. We highlight the consequences of chronic infection for tissue-specific pathology and identify open questions in this area of host-Toxoplasma interactions.
Xiao-Yu Zhao, Sarah E. Ewald
Although antiretroviral therapies (ARTs) potently inhibit HIV replication, they do not eradicate the virus. HIV persists in cellular and anatomical reservoirs that show minimal decay during ART. A large number of studies conducted during the past 20 years have shown that HIV persists in a small pool of cells harboring integrated and replication-competent viral genomes. The majority of these cells do not produce viral particles and constitute what is referred to as the latent reservoir of HIV infection. Therefore, although HIV is not considered as a typical latent virus, it can establish a state of nonproductive infection under rare circumstances, particularly in memory CD4+ T cells, which represent the main barrier to HIV eradication. While it was originally thought that the pool of latently infected cells was largely composed of cells harboring transcriptionally silent genomes, recent evidence indicates that several blocks contribute to the nonproductive state of these cells. Here, we describe the virological and immunological factors that play a role in the establishment and persistence of the pool of latently infected cells and review the current approaches aimed at eliminating the latent HIV reservoir.
Caroline Dufour, Pierre Gantner, Rémi Fromentin, Nicolas Chomont
Pediatric cancers, particularly high-risk solid tumors, urgently need effective and specific therapies. Their outlook has not appreciably improved in decades. Immunotherapies such as immune checkpoint inhibitors offer much promise, but most are only approved for use in adults. Though several hundred clinical trials have tested immune-based approaches in childhood cancers, few have been guided by biomarkers or clinical-grade assays developed to predict patient response and, ultimately, to help select those most likely to benefit. There is extensive evidence in adults to show that immune profiling has substantial predictive value, but few studies focus on childhood tumors, because of the relatively small disease population and restricted use of immune-based therapies. For instance, only one published study has retrospectively examined the immune profiles of pediatric brain tumors after immunotherapy. Furthermore, application and integration of advanced multiplex techniques has been extremely limited. Here, we review the current status of immune profiling of pediatric solid tumors, with emphasis on tumor types that represent enormous unmet clinical need, primarily in the context of immune checkpoint inhibitor therapy. Translating optimized and informative immune profiling into standard practice and access to personalized combination therapy will be critical if childhood cancers are to be treated effectively and affordably.
Rachael L. Terry, Deborah Meyran, David S. Ziegler, Michelle Haber, Paul G. Ekert, Joseph A. Trapani, Paul J. Neeson
AMPK is a heterotrimeric complex that serves as a major sensor of energy status in eukaryotic cells. Accumulating evidence depicts a complex role of dysregulated AMPK signaling in Alzheimer’s disease (AD). In this issue of the JCI, Zimmermann et al. report on their investigation of AD-specific differential expression of AMPKα1 and AMPKα2 isoforms of the catalytic subunit and demonstrate that genetic reduction of AMPKα1, but not AMPKα2, rescued cognitive decline in AD mouse models. These findings reveal an isoform-specific role of AMPKα in the pathogenesis of AD, which likely provides a more precise target for future therapeutic development.
Fanpeng Zhao, Chunyu Wang, Xiongwei Zhu
Since it was shown in the early 1950s that it is possible to induce transplantation tolerance in neonates, immune tolerance strategies have been actively pursued. It was found that T cells play a critical role in graft rejection, but can also be major players in mediating transplantation tolerance. Consequently, many experimental systems focused on T cells, often with a complete exclusion of B cells from in vivo animal models. It is now becoming clear that in addition to T cells, B cells can mediate graft rejection and transplantation tolerance. In this issue of the JCI, Khiew et al. investigated the contribution of alloreactive B cells to transplantation tolerance using a mouse cardiac transplantation model. The authors revealed a distinct tolerant B cell phenotype possessing the ability to suppress naive B cells. These data lead to a better understanding of B cell contributions to transplantation tolerance, and may inform the development of future immune tolerance protocols.
Th17 cells (producing IL-17) and Th9 cells (producing IL-9) exhibit functional plasticity, and their role in tumorigenicity is controversial. Th17/IL-17 and Th9/IL-9 exhibit critical, but often opposing, roles in tumor progression. In this issue of the JCI, Salazar et al. show that while IL-17 and IL-9 induced distinct but complementary molecular pathways, both cytokines also induced epithelial-mesenchymal transition (EMT) in lung cancer cells and promoted metastatic spreading. A key question before us now is whether IL-9 and IL-17 contribute to tumor progression in a sequential and stage-specific manner within the tumor microenvironment.
Chi Yan, Ann Richmond
Mechanical stretch of baroreceptors in the wall of the aortic arch and carotid sinus initiates autonomic reflexes to change heart rate and blood pressure for cardiovascular homeostasis. In this issue of the JCI, Lu et al. show that tentonin 3 (TTN3), a recently identified stretch-sensitive ion channel, was present at the vagus afferent nerve endings innervating the aortic arch to function as a baroreceptor. This study expands the molecular profiles of baroreceptors and provides new insights into molecular mechanisms underlying the regulation of cardiovascular functions through baroreceptor function.
Jianguo G. Gu, Dan E. Berkowitz
The mechanism by which maternal obesity influences fetal brain development and behavior is not well understood. In this issue of the JCI, Lippert et al. showed that feeding maternal mice a high-fat diet (HFD) during lactation attenuated the activity of dopamine (DA) midbrain neurons and altered the DA-related behavioral phenotype seen in the offspring. The authors further suggested that the altered excitatory and inhibitory balance between D1 medium spiny neurons (MSN) and D2 MSN mediates this behavioral phenotype. These mechanisms may provide strategies for preventing the negative effects of maternal obesity on offspring development and adult health.
Yuki Yasumoto, Tamas L. Horvath
Allergic asthma is a chronic inflammatory lung disease associated with increased cytokine secretion. Aspects of airway inflammation are also linked to a common genetic variant that corresponds to the small GTPase, Rab27, a protein involved in vesicular trafficking in immune cells. However, the mechanisms by which Rab27 contributes to airway inflammation and cytokine release remain ambiguous. In this issue of the JCI, Okunishi et al. explored the role that the Rab27 effector, exophilin-5, has in allergic inflammation. Exophilin-5–deficient mice and asthma mouse models revealed that exophilin-5 regulates IL-33 production and the Th2 response. Notably, exophilin-5 deletion enhanced IL-33 release and pathogenic Th2 responsiveness through the mTOR pathway and altered intracellular IL-33 trafficking. This work provides insights into the molecular mechanisms that underlie inflammatory lung disease.
Michael Brusilovsky, Mark Rochman, Nurit P. Azouz, Lydia E. Mack, Marc E. Rothenberg
Vaccination is a mainstay in preventive medicine, reducing morbidity and mortality from infection, largely by generating pathogen-specific neutralizing antibodies. However, standard immunization strategies are insufficient with increasing age due to immunological impediments, including defects in T follicular helper (Tfh) cells. Here, we found that Tfh generation is inversely linked to the expression of the ecto-NTPDase CD39 that modifies purinergic signaling. The lineage-determining transcription factor BCL6 inhibited CD39 expression, while increased Tfh frequencies were found in individuals with a germline polymorphism preventing transcription of ENTPD1, encoding CD39. In in vitro human and in vivo mouse studies, Tfh generation and germinal center responses were enhanced by reducing CD39 expression through the inhibition of the cAMP/PKA/p-CREB pathway, or by blocking adenosine signaling downstream of CD39 using the selective adenosine A2a receptor antagonist istradefylline. Thus, purinergic signaling in differentiating T cells can be targeted to improve vaccine responses, in particular in older individuals who have increased CD39 expression.
Wenqiang Cao, Fengqin Fang, Timothy Gould, Xuanying Li, Chulwoo Kim, Claire Gustafson, Simon Lambert, Cornelia M. Weyand, Jörg J. Goronzy
Alloantibodies in presensitized transplant candidates deposit complement membrane attack complexes (MACs) on graft endothelial cells (ECs), increasing risk of CD8+ T cell–mediated acute rejection. We recently showed that human ECs endocytose MACs into Rab5+ endosomes, creating a signaling platform that stabilizes NF-κB–inducing kinase (NIK) protein. Endosomal NIK activates both noncanonical NF-κB signaling to synthesize pro–IL-1β and an NLRP3 inflammasome to process and secrete active IL-1β. IL-1β activates ECs, increasing recruitment and activation of alloreactive effector memory CD4+ T (Tem) cells. Here, we report that IFN-γ priming induced nuclear expression of IL-15/IL-15Rα complexes in cultured human ECs and that MAC-induced IL-1β stimulated translocation of IL-15/IL-15Rα complexes to the EC surface in a canonical NF-κB–dependent process in which IL-15/IL-15Rα transpresentation increased activation and maturation of alloreactive CD8+ Tem cells. Blocking NLRP3 inflammasome assembly, IL-1 receptor, or IL-15 on ECs inhibited the augmented CD8+ Tem cell responses, indicating that this pathway is not redundant. Adoptively transferred alloantibody and mouse complement deposition induced IL-15/IL-15Rα expression by human ECs lining human coronary artery grafts in immunodeficient mice, and enhanced intimal CD8+ T cell infiltration, which was markedly reduced by inflammasome inhibition, linking alloantibody to acute rejection. Inhibiting MAC signaling may similarly limit other complement-mediated pathologies.
Catherine B. Xie, Bo Jiang, Lingfeng Qin, George Tellides, Nancy C. Kirkiles-Smith, Dan Jane-wit, Jordan S. Pober
The absence of alloantibodies is a feature of transplantation tolerance. Although the lack of T cell help has been evoked to explain this absence, herein we provide evidence for B cell–intrinsic tolerance mechanisms. Using a murine model of heart tolerance, we showed that alloreactive B cells were not deleted but rapidly lost their ability to differentiate into germinal center B cells and secrete donor-specific antibodies. We inferred that tolerant alloreactive B cells retained their ability to sense alloantigen because they continued to drive T cell maturation into CXCR5+PD-1+ T follicular helper cells. Unexpectedly, dysfunctional alloreactive B cells acquired the ability to inhibit antibody production by new naive B cells in an antigen-specific manner. Thus, tolerant alloreactive B cells contribute to transplantation tolerance by foregoing germinal center responses while retaining their ability to function as antigen-presenting cells and by actively suppressing de novo alloreactive B cell responses.
Stella H.W. Khiew, Dharmendra Jain, Jianjun Chen, Jinghui Yang, Dengping Yin, James S. Young, Alexander Dent, Roger Sciammas, Maria-Luisa Alegre, Anita S. Chong
Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the CNS. Bile acids are cholesterol metabolites that can signal through receptors on cells throughout the body, including in the CNS and the immune system. Whether bile acid metabolism is abnormal in MS is unknown. Using global and targeted metabolomic profiling, we identified lower levels of circulating bile acid metabolites in multiple cohorts of adult and pediatric patients with MS compared with controls. In white matter lesions from MS brain tissue, we noted the presence of bile acid receptors on immune and glial cells. To mechanistically examine the implications of lower levels of bile acids in MS, we studied the in vitro effects of an endogenous bile acid, tauroursodeoxycholic acid (TUDCA), on astrocyte and microglial polarization. TUDCA prevented neurotoxic (A1) polarization of astrocytes and proinflammatory polarization of microglia in a dose-dependent manner. TUDCA supplementation in experimental autoimmune encephalomyelitis reduced the severity of disease through its effects on G protein–coupled bile acid receptor 1 (GPBAR1). We demonstrate that bile acid metabolism was altered in MS and that bile acid supplementation prevented polarization of astrocytes and microglia to neurotoxic phenotypes and ameliorated neuropathology in an animal model of MS. These findings identify dysregulated bile acid metabolism as a potential therapeutic target in MS.
Pavan Bhargava, Matthew D. Smith, Leah Mische, Emily Harrington, Kathryn C. Fitzgerald, Kyle Martin, Sol Kim, Arthur Anthony Reyes, Jaime Gonzalez-Cardona, Christina Volsko, Ajai Tripathi, Sonal Singh, Kesava Varanasi, Hannah-Noelle Lord, Keya Meyers, Michelle Taylor, Marjan Gharagozloo, Elias S. Sotirchos, Bardia Nourbakhsh, Ranjan Dutta, Ellen M. Mowry, Emmanuelle Waubant, Peter A. Calabresi
The sensory nerve was recently identified as being involved in regulation of bone mass accrual. We previously discovered that prostaglandin E2 (PGE2) secreted by osteoblasts could activate sensory nerve EP4 receptor to promote bone formation by inhibiting sympathetic activity. However, the fundamental units of bone formation are active osteoblasts, which originate from mesenchymal stromal/stem cells (MSCs). Here, we found that after sensory denervation, knockout of the EP4 receptor in sensory nerves, or knockout of COX-2 in osteoblasts, could significantly promote adipogenesis and inhibit osteogenesis in adult mice. Furthermore, injection of SW033291 (a small molecule that locally increases the PGE2 level) or propranolol (a beta blocker) significantly promoted osteogenesis and inhibited adipogenesis. This effect of SW033291, but not propranolol, was abolished in conditional EP4-KO mice under normal conditions or in the bone repair process. We conclude that the PGE2/EP4 sensory nerve axis could regulate MSC differentiation in bone marrow of adult mice.
Bo Hu, Xiao Lv, Hao Chen, Peng Xue, Bo Gao, Xiao Wang, Gehua Zhen, Janet L. Crane, Dayu Pan, Shen Liu, Shuangfei Ni, Panfeng Wu, Weiping Su, Xiaonan Liu, Zemin Ling, Mi Yang, Ruoxian Deng, Yusheng Li, Lei Wang, Ying Zhang, Mei Wan, Zengwu Shao, Huajiang Chen, Wen Yuan, Xu Cao
β Cell apoptosis and dedifferentiation are 2 hotly debated mechanisms underlying β cell loss in type 2 diabetes; however, the molecular drivers underlying such events remain largely unclear. Here, we performed a side-by-side comparison of mice carrying β cell–specific deletion of ER-associated degradation (ERAD) and autophagy. We reported that, while autophagy was necessary for β cell survival, the highly conserved Sel1L-Hrd1 ERAD protein complex was required for the maintenance of β cell maturation and identity. Using single-cell RNA-Seq, we demonstrated that Sel1L deficiency was not associated with β cell loss, but rather loss of β cell identity. Sel1L-Hrd1 ERAD controlled β cell identity via TGF-β signaling, in part by mediating the degradation of TGF-β receptor 1. Inhibition of TGF-β signaling in Sel1L-deficient β cells augmented the expression of β cell maturation markers and increased the total insulin content. Our data revealed distinct pathogenic effects of 2 major proteolytic pathways in β cells, providing a framework for therapies targeting distinct mechanisms of protein quality control.
Neha Shrestha, Tongyu Liu, Yewei Ji, Rachel B. Reinert, Mauricio Torres, Xin Li, Maria Zhang, Chih-Hang Anthony Tang, Chih-Chi Andrew Hu, Chengyang Liu, Ali Naji, Ming Liu, Jiandie D. Lin, Sander Kersten, Peter Arvan, Ling Qi
AMPK is a key regulator at the molecular level for maintaining energy metabolism homeostasis. Mammalian AMPK is a heterotrimeric complex, and its catalytic α subunit exists in 2 isoforms: AMPKα1 and AMPKα2. Recent studies suggest a role of AMPKα overactivation in Alzheimer’s disease–associated (AD-associated) synaptic failure. However, whether AD-associated dementia can be improved by targeting AMPK remains unclear, and roles of AMPKα isoforms in AD pathophysiology are not understood. Here, we showed distinct disruption of hippocampal AMPKα isoform expression patterns in postmortem human AD patients and AD model mice. We further investigated the effects of brain- and isoform-specific AMPKα repression on AD pathophysiology. We found that repression of AMPKα1 alleviated cognitive deficits and synaptic failure displayed in 2 separate lines of AD model mice. In contrast, AMPKα2 suppression did not alter AD pathophysiology. Using unbiased mass spectrometry–based proteomics analysis, we identified distinct patterns of protein expression associated with specific AMPKα isoform suppression in AD model mice. Further, AD-associated hyperphosphorylation of eukaryotic elongation factor 2 (eEF2) was blunted with selective AMPKα1 inhibition. Our findings reveal isoform-specific roles of AMPKα in AD pathophysiology, thus providing insights into potential therapeutic strategies for AD and related dementia syndromes.
Helena R. Zimmermann, Wenzhong Yang, Nicole P. Kasica, Xueyan Zhou, Xin Wang, Brenna C. Beckelman, Jingyun Lee, Cristina M. Furdui, C. Dirk Keene, Tao Ma
Plasmacytoid DCs (pDCs), the major producers of type I interferon, are principally recognized as key mediators of antiviral immunity. However, their role in tumor immunity is less clear. Depending on the context, pDCs can promote or suppress antitumor immune responses. In this study, we identified a naturally occurring pDC subset expressing high levels of OX40 (OX40+ pDC) enriched in the tumor microenvironment (TME) of head and neck squamous cell carcinoma. OX40+ pDCs were distinguished by a distinct immunostimulatory phenotype, cytolytic function, and ability to synergize with conventional DCs (cDCs) in generating potent tumor antigen–specific CD8+ T cell responses. Transcriptomically, we found that they selectively utilized EIF2 signaling and oxidative phosphorylation pathways. Moreover, depletion of pDCs in the murine OX40+ pDC–rich tumor model accelerated tumor growth. Collectively, we present evidence of a pDC subset in the TME that favors antitumor immunity.
Kate Poropatich, Donye Dominguez, Wen-Ching Chan, Jorge Andrade, Yuanyuan Zha, Brian Wray, Jason Miska, Lei Qin, Lisa Cole, Sydney Coates, Urjeet Patel, Sandeep Samant, Bin Zhang
Proliferation of CD4+ T cells harboring HIV-1 proviruses is a major contributor to viral persistence in people on antiretroviral therapy (ART). To determine whether differential rates of clonal proliferation or HIV-1–specific cytotoxic T lymphocyte (CTL) pressure shape the provirus landscape, we performed an intact proviral DNA assay (IPDA) and obtained 661 near–full-length provirus sequences from 8 individuals with suppressed viral loads on ART at time points 7 years apart. We observed slow decay of intact proviruses but no changes in the proportions of various types of defective proviruses. The proportion of intact proviruses in expanded clones was similar to that of defective proviruses in clones. Intact proviruses observed in clones did not have more escaped CTL epitopes than intact proviruses observed as singlets. Concordantly, total proviruses at later time points or observed in clones were not enriched in escaped or unrecognized epitopes. Three individuals with natural control of HIV-1 infection (controllers) on ART, included because controllers have strong HIV-1–specific CTL responses, had a smaller proportion of intact proviruses but a distribution of defective provirus types and escaped or unrecognized epitopes similar to that of the other individuals. This work suggests that CTL selection does not significantly check clonal proliferation of infected cells or greatly alter the provirus landscape in people on ART.
Annukka A.R. Antar, Katharine M. Jenike, Sunyoung Jang, Danielle N. Rigau, Daniel B. Reeves, Rebecca Hoh, Melissa R. Krone, Jeanne C. Keruly, Richard D. Moore, Joshua T. Schiffer, Bareng A.S. Nonyane, Frederick M. Hecht, Steven G. Deeks, Janet D. Siliciano, Ya-Chi Ho, Robert F. Siliciano
Immune microenvironment plays a critical role in lung cancer control versus progression and metastasis. In this investigation, we explored the effect of tumor-infiltrating lymphocyte subpopulations on lung cancer biology by studying in vitro cocultures, in vivo mouse models, and human lung cancer tissue. Lymphocyte conditioned media (CM) induced epithelial-mesenchymal transition (EMT) and migration in both primary human lung cancer cells and cell lines. Correspondingly, major accumulation of Th9 and Th17 cells was detected in human lung cancer tissue and correlated with poor survival. Coculturing lung cancer cells with Th9/Th17 cells or exposing them to the respective CM induced EMT in cancer cells and modulated the expression profile of genes implicated in EMT and metastasis. These features were reproduced by the signatory cytokines IL-9 and IL-17, with gene regulatory profiles evoked by these cytokines partly overlapping and partly complementary. Coinjection of Th9/Th17 cells with tumor cells in WT, Rag1–/–, Il9r–/–, and Il17ra–/– mice altered tumor growth and metastasis. Accordingly, inhibition of IL-9 or IL-17 cytokines by neutralizing antibodies decreased EMT and slowed lung cancer progression and metastasis. In conclusion, Th9 and Th17 lymphocytes induce lung cancer cell EMT, thereby promoting migration and metastatic spreading and offering potentially novel therapeutic strategies.
Ylia Salazar, Xiang Zheng, David Brunn, Hartmann Raifer, Felix Picard, Yajuan Zhang, Hauke Winter, Stefan Guenther, Andreas Weigert, Benno Weigmann, Laure Dumoutier, Jean-Christophe Renauld, Ari Waisman, Anja Schmall, Amanda Tufman, Ludger Fink, Bernhard Brüne, Tobias Bopp, Friedrich Grimminger, Werner Seeger, Soni Savai Pullamsetti, Magdalena Huber, Rajkumar Savai
Allergic asthma is mediated by Th2 responses to inhaled allergens. Although previous experiments indicated that Notch signaling activates expression of the key Th2 transcription factor Gata3, it remains controversial how Notch promotes allergic airway inflammation. Here we show that T cell–specific Notch deficiency in mice prevented house dust mite–driven eosinophilic airway inflammation and significantly reduced Th2 cytokine production, serum IgE levels, and airway hyperreactivity. However, transgenic Gata3 overexpression in Notch-deficient T cells only partially rescued this phenotype. We found that Notch signaling was not required for T cell proliferation or Th2 polarization. Instead, Notch-deficient in vitro–polarized Th2 cells showed reduced accumulation in the lungs upon in vivo transfer and allergen challenge, as Notch-deficient Th2 cells were retained in the lung-draining lymph nodes. Transcriptome analyses and sequential adoptive transfer experiments revealed that while Notch-deficient lymph node Th2 cells established competence for lung migration, they failed to upregulate sphingosine-1-phosphate receptor 1 (S1PR1) and its critical upstream transcriptional activator Krüppel-like factor 2 (KLF2). As this KLF2/S1PR1 axis represents the essential cell-intrinsic regulator of T cell lymph node egress, we conclude that the druggable Notch signaling pathway licenses the Th2 response in allergic airway inflammation via promoting lymph node egress.
Irma Tindemans, Anne van Schoonhoven, Alex KleinJan, Marjolein J.W. de Bruijn, Melanie Lukkes, Menno van Nimwegen, Anouk van den Branden, Ingrid M. Bergen, Odilia B.J. Corneth, Wilfred F.J. van IJcken, Ralph Stadhouders, Rudi W. Hendriks
BACKGROUND Postreceptor insulin resistance (IR) is associated with hyperglycemia and hepatic steatosis. However, receptor-level IR (e.g., insulin receptor pathogenic variants, INSR) causes hyperglycemia without steatosis. We examined 4 pathologic conditions of IR in humans to examine pathways controlling lipid metabolism and gluconeogenesis.METHODS Cross-sectional study of severe receptor IR (INSR, n = 7) versus postreceptor IR that was severe (lipodystrophy, n = 14), moderate (type 2 diabetes, n = 9), or mild (obesity, n = 8). Lipolysis (glycerol turnover), hepatic glucose production (HGP), gluconeogenesis (deuterium incorporation from body water into glucose), hepatic triglyceride (magnetic resonance spectroscopy), and hepatic fat oxidation (plasma β-hydroxybutyrate) were measured.RESULTS Lipolysis was 2- to 3-fold higher in INSR versus all other groups, and HGP was 2-fold higher in INSR and lipodystrophy versus type 2 diabetes and obesity (P < 0.001), suggesting severe adipose and hepatic IR. INSR subjects had a higher contribution of gluconeogenesis to HGP, approximately 77%, versus 52% to 59% in other groups (P = 0.0001). Despite high lipolysis, INSR subjects had low hepatic triglycerides (0.5% [interquartile range 0.1%–0.5%]), in contrast to lipodystrophy (10.6% [interquartile range 2.8%–17.1%], P < 0.0001). β-hydroxybutyrate was 2- to 7-fold higher in INSR versus all other groups (P < 0.0001), consistent with higher hepatic fat oxidation.CONCLUSION These data support a key pathogenic role of adipose tissue IR to increase glycerol and FFA availability to the liver in both receptor and postreceptor IR. However, the fate of FFA diverges in these populations. In receptor-level IR, FFA oxidation drives gluconeogenesis rather than being reesterified to triglyceride. In contrast, in postreceptor IR, FFA contributes to both gluconeogenesis and hepatic steatosis.TRIAL REGISTRATION ClinicalTrials.gov NCT01778556, NCT00001987, and NCT02457897.FUNDING National Institute of Diabetes and Digestive and Kidney Diseases, US Department of Agriculture/Agricultural Research Service 58-3092-5-001.
Hilal Sekizkardes, Stephanie Therese Chung, Shaji Chacko, Morey W. Haymond, Megan Startzell, Mary Walter, Peter J. Walter, Marissa Lightbourne, Rebecca J. Brown
Emerging immune therapy, such as with the anti–programmed cell death–1 (anti–PD-1) monoclonal antibody nivolumab, has shown efficacy in tumor suppression. Patients with terminal cancer suffer from cancer pain as a result of bone metastasis and bone destruction, but how PD-1 blockade affects bone cancer pain remains unknown. Here, we report that mice lacking Pdcd1 (Pd1−/−) demonstrated remarkable protection against bone destruction induced by femoral inoculation of Lewis lung cancer cells. Compared with WT mice, Pd1−/− mice exhibited increased baseline pain sensitivity, but the development of bone cancer pain was compromised in Pd1−/− mice. Consistently, these beneficial effects in Pd1−/− mice were recapitulated by repeated i.v. applications of nivolumab in WT mice, even though nivolumab initially increased mechanical and thermal pain. Notably, PD-1 deficiency or nivolumab treatment inhibited osteoclastogenesis without altering tumor burden. PD-L1 and CCL2 are upregulated within the local tumor microenvironment, and PD-L1 promoted RANKL-induced osteoclastogenesis through JNK activation and CCL2 secretion. Bone cancer upregulated CCR2 in primary sensory neurons, and CCR2 antagonism effectively reduced bone cancer pain. Our findings suggest that, despite a transient increase in pain sensitivity following each treatment, anti–PD-1 immunotherapy could produce long-term benefits in preventing bone destruction and alleviating bone cancer pain by suppressing osteoclastogenesis.
Kaiyuan Wang, Yun Gu, Yihan Liao, Sangsu Bang, Christopher R. Donnelly, Ouyang Chen, Xueshu Tao, Anthony J. Mirando, Matthew J. Hilton, Ru-Rong Ji
Enteric neuronal degeneration, as seen in inflammatory bowel disease, obesity, and diabetes, can lead to gastrointestinal dysmotility. Pyroptosis is a novel form of programmed cell death but little is known about its role in enteric neuronal degeneration. We observed higher levels of cleaved caspase-1, a marker of pyroptosis, in myenteric ganglia of overweight and obese human subjects compared with normal-weight subjects. Western diet–fed (WD-fed) mice exhibited increased myenteric neuronal pyroptosis, delayed colonic transit, and impaired electric field stimulation–induced colonic relaxation responses. WD increased TLR4 expression and cleaved caspase-1 in myenteric nitrergic neurons. Overactivation of nitrergic neuronal NF-κB signaling resulted in increased pyroptosis and delayed colonic motility. In caspase-11–deficient mice, WD did not induce nitrergic myenteric neuronal pyroptosis and colonic dysmotility. To understand the contributions of saturated fatty acids and bacterial products to the steps leading to enteric neurodegeneration, we performed in vitro experiments using mouse enteric neurons. Palmitate and lipopolysaccharide (LPS) increased nitrergic, but not cholinergic, enteric neuronal pyroptosis. LPS gained entry to the cytosol in the presence of palmitate, activating caspase-11 and gasdermin D, leading to pyroptosis. These results support a role of the caspase-11–mediated pyroptotic pathway in WD-induced myenteric nitrergic neuronal degeneration and colonic dysmotility, providing important therapeutic targets for enteric neuropathy.
Lan Ye, Ge Li, Anna Goebel, Abhinav V. Raju, Feng Kong, Yanfei Lv, Kailin Li, Yuanjun Zhu, Shreya Raja, Peijian He, Fang Li, Simon Musyoka Mwangi, Wenhui Hu, Shanthi Srinivasan
Children and adults with Philadelphia chromosome–like B cell acute lymphoblastic leukemia (Ph-like B-ALL) experience high relapse rates despite best-available conventional chemotherapy. Ph-like ALL is driven by genetic alterations that activate constitutive cytokine receptor and kinase signaling, and early-phase trials are investigating the potential of the addition of tyrosine kinase inhibitors (TKIs) to chemotherapy to improve clinical outcomes. However, preclinical studies have shown that JAK or PI3K pathway inhibition is insufficient to eradicate the most common cytokine receptor–like factor 2–rearranged (CRLF2-rearranged) Ph-like ALL subset. We thus sought to define additional essential signaling pathways required in Ph-like leukemogenesis for improved therapeutic targeting. Herein, we describe an adaptive signaling plasticity of CRLF2-rearranged Ph-like ALL following selective TKI pressure, which occurs in the absence of genetic mutations. Interestingly, we observed that Ph-like ALL cells have activated SRC, ERK, and PI3K signaling consistent with activated B cell receptor (BCR) signaling, although they do not express cell surface μ-heavy chain (μHC). Combinatorial targeting of JAK/STAT, PI3K, and “BCR-like” signaling with multiple TKIs and/or dexamethasone prevented this signaling plasticity and induced complete cell death, demonstrating a more optimal and clinically pragmatic therapeutic strategy for CRLF2-rearranged Ph-like ALL.
Christian Hurtz, Gerald B. Wertheim, Joseph P. Loftus, Daniel Blumenthal, Anne Lehman, Yong Li, Asen Bagashev, Bryan Manning, Katherine D. Cummins, Janis K. Burkhardt, Alexander E. Perl, Martin Carroll, Sarah K. Tasian
Germinal center (GC) responses require B cells to respond to a dynamic set of intercellular and microenvironmental signals that instruct B cell positioning, differentiation, and metabolic reprogramming. RHO-associated coiled-coil–containing protein kinase 2 (ROCK2), a serine-threonine kinase that can be therapeutically targeted by ROCK inhibitors or statins, is a key downstream effector of RHOA GTPases. Although RHOA-mediated pathways are emerging as critical regulators of GC responses, the role of ROCK2 in B cells is unknown. Here, we found that ROCK2 was activated in response to key T cell signals like CD40 and IL-21 and that it regulated GC formation and maintenance. RNA-Seq analyses revealed that ROCK2 controlled a unique transcriptional program in GC B cells that promoted optimal GC polarization and cholesterol biosynthesis. ROCK2 regulated this program by restraining AKT activation and subsequently enhancing FOXO1 activity. ATAC-Seq (assay for transposase-accessible chromatin with high-throughput sequencing) and biochemical analyses revealed that the effects of ROCK2 on cholesterol biosynthesis were instead mediated via a novel mechanism. ROCK2 directly phosphorylated interferon regulatory factor 8 (IRF8), a crucial mediator of GC responses, and promoted its interaction with sterol regulatory element–binding transcription factor 2 (SREBP2) at key regulatory regions controlling the expression of cholesterol biosynthetic enzymes, resulting in optimal recruitment of SREBP2 at these sites. These findings thus uncover ROCK2 as a multifaceted and therapeutically targetable regulator of GC responses.
Edd Ricker, Yurii Chinenov, Tania Pannellini, Danny Flores-Castro, Chao Ye, Sanjay Gupta, Michela Manni, James K. Liao, Alessandra B. Pernis
The baroreceptor reflex is a powerful neural feedback that regulates arterial pressure (AP). Mechanosensitive channels transduce pulsatile AP to electrical signals in baroreceptors. Here we show that tentonin 3 (TTN3/TMEM150C), a cation channel activated by mechanical strokes, is essential for detecting AP changes in the aortic arch. TTN3 was expressed in nerve terminals in the aortic arch and nodose ganglion (NG) neurons. Genetic ablation of Ttn3 induced ambient hypertension, tachycardia, AP fluctuations, and impaired baroreflex sensitivity. Chemogenetic silencing or activation of Ttn3+ neurons in the NG resulted in an increase in AP and heart rate, or vice versa. More important, overexpression of Ttn3 in the NG of Ttn3–/– mice reversed the cardiovascular changes observed in Ttn3–/– mice. We conclude that TTN3 is a molecular component contributing to the sensing of dynamic AP changes in baroreceptors.
Huan-Jun Lu, Thien-Luan Nguyen, Gyu-Sang Hong, Sungmin Pak, Hyesu Kim, Hyungsup Kim, Dong-Yoon Kim, Sung-Yon Kim, Yiming Shen, Pan Dong Ryu, Mi-Ock Lee, Uhtaek Oh
Unchecked inflammation is a hallmark of inflammatory tissue injury in diseases such as acute respiratory distress syndrome (ARDS). Yet the mechanisms of inflammatory lung injury remain largely unknown. Here we showed that bacterial endotoxin lipopolysaccharide (LPS) and cecal ligation and puncture–induced (CLP-induced) polymicrobial sepsis decreased the expression of transcription factor cAMP response element binding (CREB) in lung endothelial cells. We demonstrated that endothelial CREB was crucial for VE-cadherin transcription and the formation of the normal restrictive endothelial adherens junctions. The inflammatory cytokine IL-1β reduced cAMP generation and CREB-mediated transcription of VE-cadherin. Furthermore, endothelial cell–specific deletion of CREB induced lung vascular injury whereas ectopic expression of CREB in the endothelium prevented the injury. We also observed that rolipram, which inhibits type 4 cyclic nucleotide phosphodiesterase–mediated (PDE4-mediated) hydrolysis of cAMP, prevented endotoxemia-induced lung vascular injury since it preserved CREB-mediated VE-cadherin expression. These data demonstrate the fundamental role of the endothelial cAMP-CREB axis in promoting lung vascular integrity and suppressing inflammatory injury. Therefore, strategies aimed at enhancing endothelial CREB-mediated VE-cadherin transcription are potentially useful in preventing sepsis-induced lung vascular injury in ARDS.
Shiqin Xiong, Zhigang Hong, Long Shuang Huang, Yoshikazu Tsukasaki, Saroj Nepal, Anke Di, Ming Zhong, Wei Wu, Zhiming Ye, Xiaopei Gao, Gadiparthi N. Rao, Dolly Mehta, Jalees Rehman, Asrar B. Malik
The Warburg effect is a tumor-related phenomenon that could potentially be targeted therapeutically. Here, we showed that glioblastoma (GBM) cultures and patients’ tumors harbored super-enhancers in several genes related to the Warburg effect. By conducting a transcriptome analysis followed by ChIP-Seq coupled with a comprehensive metabolite analysis in GBM models, we found that FDA-approved global (panobinostat, vorinostat) and selective (romidepsin) histone deacetylase (HDAC) inhibitors elicited metabolic reprogramming in concert with disruption of several Warburg effect–related super-enhancers. Extracellular flux and carbon-tracing analyses revealed that HDAC inhibitors blunted glycolysis in a c-Myc–dependent manner and lowered ATP levels. This resulted in the engagement of oxidative phosphorylation (OXPHOS) driven by elevated fatty acid oxidation (FAO), rendering GBM cells dependent on these pathways. Mechanistically, interference with HDAC1/-2 elicited a suppression of c-Myc protein levels and a concomitant increase in 2 transcriptional drivers of oxidative metabolism, PGC1α and PPARD, suggesting an inverse relationship. Rescue and ChIP experiments indicated that c-Myc bound to the promoter regions of PGC1α and PPARD to counteract their upregulation driven by HDAC1/-2 inhibition. Finally, we demonstrated that combination treatment with HDAC and FAO inhibitors extended animal survival in patient-derived xenograft model systems in vivo more potently than single treatments in the absence of toxicity.
Trang Thi Thu Nguyen, Yiru Zhang, Enyuan Shang, Chang Shu, Consuelo Torrini, Junfei Zhao, Elena Bianchetti, Angeliki Mela, Nelson Humala, Aayushi Mahajan, Arif O. Harmanci, Zhengdeng Lei, Mark Maienschein-Cline, Catarina M. Quinzii, Mike-Andrew Westhoff, Georg Karpel-Massler, Jeffrey N. Bruce, Peter Canoll, Markus D. Siegelin
T follicular helper (Tfh) cells are indispensable for the formation of germinal center (GC) reactions, whereas T follicular regulatory (Tfr) cells inhibit Tfh-mediated GC responses. Aberrant activation of Tfh cells contributes substantially to the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus (SLE). Nonetheless, the molecular mechanisms mitigating excessive Tfh cell differentiation are not fully understood. Herein we demonstrate that the adenovirus E4 promoter-binding protein (E4BP4) mediates a feedback loop and acts as a transcriptional brake to inhibit Tfh cell differentiation. Furthermore, we show that such an immunological mechanism is compromised in patients with SLE. Establishing mice with either conditional knockout (cKO) or knockin (cKI) of the E4bp4 gene in T cells reveals that E4BP4 strongly inhibits Tfh cell differentiation. Mechanistically, E4BP4 regulates Bcl6 transcription by recruiting the repressive epigenetic modifiers HDAC1 and EZH2. E4BP4 phosphorylation site mutants have limited capability with regard to inhibiting Tfh cell differentiation. In SLE, we detected impaired phosphorylation of E4BP4, finding that this compromised transcription factor is positively correlated with disease activity. These findings unveiled molecular mechanisms by which E4BP4 restrains Tfh cell differentiation, whose compromised function is associated with uncontrolled autoimmune reactions in SLE.
Zijun Wang, Ming Zhao, Jinghua Yin, Limin Liu, Longyuan Hu, Yi Huang, Aiyun Liu, Jiajun Ouyang, Xiaoli Min, Shijia Rao, Wenhui Zhou, Haijing Wu, Akihiko Yoshimura, Qianjin Lu
Ischemic acute kidney injury (AKI), a complication that frequently occurs in hospital settings, is often associated with hemodynamic compromise, sepsis, cardiac surgery, or exposure to nephrotoxins. Here, using a murine renal ischemia/reperfusion injury (IRI) model, we show that intercalated cells (ICs) rapidly adopted a proinflammatory phenotype after IRI. Wwe demonstrate that during the early phase of AKI either blockade of the proinflammatory P2Y14 receptor located on the apical membrane of ICs or ablation of the gene encoding the P2Y14 receptor in ICs (a) inhibited IRI-induced increase of chemokine expression in ICs, (b) reduced neutrophil and monocyte renal infiltration, (c) reduced the extent of kidney dysfunction, and (d) attenuated proximal tubule damage. These observations indicate that the P2Y14 receptor participates in the very first inflammatory steps associated with ischemic AKI. In addition, we show that the concentration of the P2Y14 receptor ligand UDP-glucose (UDP-Glc) was higher in urine samples from intensive care unit patients who developed AKI compared with patients without AKI. In particular, we observed a strong correlation between UDP-Glc concentration and the development of AKI in cardiac surgery patients. Our study identifies the UDP-Glc/P2Y14 receptor axis as a potential target for the prevention and/or attenuation of ischemic AKI.
Maria Agustina Battistone, Alexandra C. Mendelsohn, Raul German Spallanzani, Andrew S. Allegretti, Rachel N. Liberman, Juliana Sesma, Sahir Kalim, Susan M. Wall, Joseph V. Bonventre, Eduardo R. Lazarowski, Dennis Brown, Sylvie Breton
BACKGROUND Novel therapeutic approaches are critically needed for Staphylococcus aureus bloodstream infections (BSIs), particularly for methicillin-resistant S. aureus (MRSA). Exebacase, a first-in-class antistaphylococcal lysin, is a direct lytic agent that is rapidly bacteriolytic, eradicates biofilms, and synergizes with antibiotics.METHODS In this superiority-design study, we randomly assigned 121 patients with S. aureus BSI/endocarditis to receive a single dose of exebacase or placebo. All patients received standard-of-care antibiotics. The primary efficacy endpoint was clinical outcome (responder rate) on day 14.RESULTS Clinical responder rates on day 14 were 70.4% and 60.0% in the exebacase + antibiotics and antibiotics-alone groups, respectively (difference = 10.4, 90% CI [–6.3, 27.2], P = 0.31), and were 42.8 percentage points higher in the prespecified exploratory MRSA subgroup (74.1% vs. 31.3%, difference = 42.8, 90% CI [14.3, 71.4], ad hoc P = 0.01). Rates of adverse events (AEs) were similar in both groups. No AEs of hypersensitivity to exebacase were reported. Thirty-day all-cause mortality rates were 9.7% and 12.8% in the exebacase + antibiotics and antibiotics-alone groups, respectively, with a notable difference in MRSA patients (3.7% vs. 25.0%, difference = –21.3, 90% CI [–45.1, 2.5], ad hoc P = 0.06). Among MRSA patients in the United States, median length of stay was 4 days shorter and 30-day hospital readmission rates were 48% lower in the exebacase-treated group compared with antibiotics alone.CONCLUSION This study establishes proof of concept for exebacase and direct lytic agents as potential therapeutics and supports conduct of a confirmatory study focused on exebacase to treat MRSA BSIs.TRIAL REGISTRATION Clinicaltrials.gov NCT03163446.FUNDING ContraFect Corporation.
Vance G. Fowler Jr., Anita F. Das, Joy Lipka-Diamond, Raymond Schuch, Roger Pomerantz, Luis Jáuregui-Peredo, Adam Bressler, David Evans, Gregory J. Moran, Mark E. Rupp, Robert Wise, G. Ralph Corey, Marcus Zervos, Pamela S. Douglas, Cara Cassino
The maternal perinatal environment modulates brain formation, and altered maternal nutrition has been linked to the development of metabolic and psychiatric disorders in the offspring. Here, we showed that maternal high-fat diet (HFD) feeding during lactation in mice elicits long-lasting changes in gene expression in the offspring’s dopaminergic circuitry. This translated into silencing of dopaminergic midbrain neurons, reduced connectivity to their downstream targets, and reduced stimulus-evoked dopamine (DA) release in the striatum. Despite the attenuated activity of DA midbrain neurons, offspring from mothers exposed to HFD feeding exhibited a sexually dimorphic expression of DA-related phenotypes, i.e., hyperlocomotion in males and increased intake of palatable food and sucrose in females. These phenotypes arose from concomitantly increased spontaneous activity of D1 medium spiny neurons (MSNs) and profoundly decreased D2 MSN projections. Overall, we have unraveled a fundamental restructuring of dopaminergic circuitries upon time-restricted altered maternal nutrition to induce persistent behavioral changes in the offspring.
R.N. Lippert, S. Hess, P. Klemm, L.M. Burgeno, T. Jahans-Price, M.E. Walton, P. Kloppenburg, J.C. Brüning
Hidradenitis suppurativa (HS) is a chronic, relapsing, inflammatory skin disease. HS appears to be a primary abnormality in the pilosebaceous-apocrine unit. In this work, we characterized hair follicle stem cells (HFSCs) isolated from HS patients and more precisely the outer root sheath cells (ORSCs). We showed that hair follicle cells from HS patients had an increased number of proliferating progenitor cells and lost quiescent stem cells. Remarkably, we also showed that the progression of replication forks was altered in ORSCs from hair follicles of HS patients, leading to activation of the ATR/CHK1 pathway. These alterations were associated with an increased number of micronuclei and with the presence of cytoplasmic ssDNA, leading to the activation of the IFI16/STING pathway and the production of type I IFNs. This mechanistic analysis of the etiology of HS in the HFSC compartment establishes a formal link between genetic predisposition and skin inflammation observed in HS.
Cindy Orvain, Yea-Lih Lin, Francette Jean-Louis, Hakim Hocini, Barbara Hersant, Yamina Bennasser, Nicolas Ortonne, Claire Hotz, Pierre Wolkenstein, Michele Boniotto, Pascaline Tisserand, Cécile Lefebvre, Jean-Daniel Lelièvre, Monsef Benkirane, Philippe Pasero, Yves Lévy, Sophie Hüe
Type 2 diabetes mellitus (T2DM) has become an expanding global public health problem. Although the glucocorticoid receptor (GR) is an important regulator of glucose metabolism, the relationship between circulating glucocorticoids (GCs) and the features of T2DM remains controversial. Here, we show that 17-hydroxyprogesterone (17-OHP), an intermediate steroid in the biosynthetic pathway that converts cholesterol to cortisol, binds to and stimulates the transcriptional activity of GR. Hepatic 17-OHP concentrations are increased in diabetic mice and patients due to aberrantly increased expression of Cyp17A1. Systemic administration of 17-OHP or overexpression of Cyp17A1 in the livers of lean mice promoted the pathogenesis of hyperglycemia and insulin resistance, whereas knockdown of Cyp17A1 abrogated metabolic disorders in obese mice. Therefore, our results identify a Cyp17A1/17-OHP/GR–dependent pathway in the liver that mediates obesity-induced hyperglycemia, suggesting that selectively targeting hepatic Cyp17A1 may provide a therapeutic avenue for treating T2DM.
Yan Lu, E Wang, Ying Chen, Bing Zhou, Jiejie Zhao, Liping Xiang, Yiling Qian, Jingjing Jiang, Lin Zhao, Xuelian Xiong, Zhiqiang Lu, Duojiao Wu, Bin Liu, Jing Yan, Rong Zhang, Huijie Zhang, Cheng Hu, Xiaoying Li
Microbial ingestion by a macrophage results in the formation of an acidic phagolysosome but the host cell has no information on the pH susceptibility of the ingested organism. This poses a problem for the macrophage and raises the fundamental question of how the phagocytic cell optimizes the acidification process to prevail. We analyzed the dynamical distribution of phagolysosomal pH in murine and human macrophages that had ingested live or dead Cryptococcus neoformans cells, or inert beads. Phagolysosomal acidification produced a range of pH values that approximated normal distributions, but these differed from normality depending on ingested particle type. Analysis of the increments of pH reduction revealed no forbidden ordinal patterns, implying that the phagosomal acidification process was a stochastic dynamical system. Using simulation modeling, we determined that by stochastically acidifying a phagolysosome to a pH within the observed distribution, macrophages sacrificed a small amount of overall fitness to gain the benefit of reduced variation in fitness. Hence, chance in the final phagosomal pH introduces unpredictability to the outcome of the macrophage-microbe, which implies a bet-hedging strategy that benefits the macrophage. While bet hedging is common in biological systems at the organism level, our results show its use at the organelle and cellular level.
Quigly Dragotakes, Kaitlin M. Stouffer, Man Shun Fu, Yehonatan Sella, Christine Youn, Olivia Insun Yoon, Carlos M. De Leon-Rodriguez, Joudeh B. Freij, Aviv Bergman, Arturo Casadevall
Food allergies are a major clinical problem and are driven by IgE antibodies (Abs) specific for food antigens (Ags). T follicular regulatory (Tfr) cells are a specialized subset of FOXP3+ T cells that modulate Ab responses. Here, we analyzed the role of Tfr cells in regulating Ag-specific IgE using a peanut-based food allergy model in mice. Peanut-specific IgE titers and anaphylaxis responses were significantly blunted in Tfr cell–deficient Foxp3-Cre Bcl6fl/fl mice. Loss of Tfr cells led to greatly increased nonspecific IgE levels, showing that Tfr cells have both helper and suppressor functions in IgE production in the germinal center (GC) that work together to facilitate the production of Ag-specific IgE. Foxp3-Cre Ptenfl/fl mice with augmented Tfr cell responses had markedly higher levels of peanut-specific IgE, revealing an active helper function by Tfr cells on Ag-specific IgE. The helper function of Tfr cells for IgE production involves IL-10, and the loss of IL-10 signaling by B cells led to a severely curtailed peanut-specific IgE response, decreased GCB cell survival, and loss of GC dark zone B cells after peanut sensitization. We thus reveal that Tfr cells have an unexpected helper role in promoting food allergy and may represent a target for drug development.
Markus M. Xie, Qiang Chen, Hong Liu, Kai Yang, Byunghee Koh, Hao Wu, Soheila J. Maleki, Barry K. Hurlburt, Joan Cook-Mills, Mark H. Kaplan, Alexander L. Dent
Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults. Vascular pericyte degeneration is the predominant clinical manifestation of DR, yet the mechanism governing pericyte degeneration is poorly understood. Circular RNAs (circRNAs) play important roles in multiple biological processes and disease progression. Here, we investigated the role of circRNA in pericyte biology and diabetes-induced retinal vascular dysfunction. cZNF532 expression was upregulated in pericytes under diabetic stress, in the retinal vessels of a diabetic murine model, and in the vitreous humor of diabetic patients. cZNF532 silencing reduced the viability, proliferation, and differentiation of pericytes and suppressed the recruitment of pericytes toward endothelial cells in vitro. cZNF532 regulated pericyte biology by acting as a miR-29a-3p sponge and inducing increased expression of NG2, LOXL2, and CDK2. Knockdown of cZNF532 or overexpression of miR-29a-3p aggravated streptozotocin-induced retinal pericyte degeneration and vascular dysfunction. By contrast, overexpression of cZNF532 or inhibition of miR-29a-3p ameliorated human diabetic vitreous–induced retinal pericyte degeneration and vascular dysfunction. Collectively, these data identify a circRNA-mediated mechanism that coordinates pericyte biology and vascular homeostasis in DR. Induction of cZNF532 or antagonism of miR-29a-3p is an exploitable therapeutic approach for the treatment of DR.
Qin Jiang, Chang Liu, Chao-Peng Li, Shan-Shan Xu, Mu-Di Yao, Hui-Min Ge, Ya-Nan Sun, Xiu-Miao Li, Shu-Jie Zhang, Kun Shan, Bai-Hui Liu, Jin Yao, Chen Zhao, Biao Yan
Cancer cells can develop a strong addiction to discrete molecular regulators, which control the aberrant gene expression programs that drive and maintain the cancer phenotype. Here, we report the identification of the RNA-binding protein HuR/ELAVL1 as a central oncogenic driver for malignant peripheral nerve sheath tumors (MPNSTs), which are highly aggressive sarcomas that originate from cells of the Schwann cell lineage. HuR was found to be highly elevated and bound to a multitude of cancer-associated transcripts in human MPNST samples. Accordingly, genetic and pharmacological inhibition of HuR had potent cytostatic and cytotoxic effects on tumor growth, and strongly suppressed metastatic capacity in vivo. Importantly, we linked the profound tumorigenic function of HuR to its ability to simultaneously regulate multiple essential oncogenic pathways in MPNST cells, including the Wnt/β-catenin, YAP/TAZ, RB/E2F, and BET pathways, which converge on key transcriptional networks. Given the exceptional dependency of MPNST cells on HuR for survival, proliferation, and dissemination, we propose that HuR represents a promising therapeutic target for MPNST treatment.
Marta Palomo-Irigoyen, Encarni Pérez-Andrés, Marta Iruarrizaga-Lejarreta, Adrián Barreira-Manrique, Miguel Tamayo-Caro, Laura Vila-Vecilla, Leire Moreno-Cugnon, Nagore Beitia, Daniela Medrano, David Fernández-Ramos, Juan José Lozano, Satoshi Okawa, José L. Lavín, Natalia Martín-Martín, James D. Sutherland, Virginia Guitiérez de Juan, Monika Gonzalez-Lopez, Nuria Macías-Cámara, David Mosén-Ansorena, Liyam Laraba, C. Oliver Hanemann, Emanuela Ercolano, David B. Parkinson, Christopher W. Schultz, Marcos J. Araúzo-Bravo, Alex M. Ascensión, Daniela Gerovska, Haizea Iribar, Ander Izeta, Peter Pytel, Philipp Krastel, Alessandro Provenzani, Pierfausto Seneci, Ruben D. Carrasco, Antonio Del Sol, María Luz Martinez-Chantar, Rosa Barrio, Eduard Serra, Conxi Lazaro, Adrienne M. Flanagan, Myriam Gorospe, Nancy Ratner, Ana M. Aransay, Arkaitz Carracedo, Marta Varela-Rey, Ashwin Woodhoo
Myeloid cells comprise a major component of the tumor microenvironment (TME) that promotes tumor growth and immune evasion. By employing a small-molecule inhibitor of glutamine metabolism, not only were we able to inhibit tumor growth, but we markedly inhibited the generation and recruitment of myeloid-derived suppressor cells (MDSCs). Targeting tumor glutamine metabolism led to a decrease in CSF3 and hence recruitment of MDSCs as well as immunogenic cell death, leading to an increase in inflammatory tumor-associated macrophages (TAMs). Alternatively, inhibiting glutamine metabolism of the MDSCs themselves led to activation-induced cell death and conversion of MDSCs to inflammatory macrophages. Surprisingly, blocking glutamine metabolism also inhibited IDO expression of both the tumor and myeloid-derived cells, leading to a marked decrease in kynurenine levels. This in turn inhibited the development of metastasis and further enhanced antitumor immunity. Indeed, targeting glutamine metabolism rendered checkpoint blockade–resistant tumors susceptible to immunotherapy. Overall, our studies define an intimate interplay between the unique metabolism of tumors and the metabolism of suppressive immune cells.
Min-Hee Oh, Im-Hong Sun, Liang Zhao, Robert D. Leone, Im-Meng Sun, Wei Xu, Samuel L. Collins, Ada J. Tam, Richard L. Blosser, Chirag H. Patel, Judson M. Englert, Matthew L. Arwood, Jiayu Wen, Yee Chan-Li, Lukáš Tenora, Pavel Majer, Rana Rais, Barbara S. Slusher, Maureen R. Horton, Jonathan D. Powell
Attention deficit/hyperactivity disorder (ADHD) is a common and heritable phenotype frequently accompanied by insomnia, anxiety, and depression. Here, using a reverse phenotyping approach, we report heterozygous coding variations in the core circadian clock gene cryptochrome 1 in 15 unrelated multigenerational families with combined ADHD and insomnia. The variants led to functional alterations in the circadian molecular rhythms, providing a mechanistic link to the behavioral symptoms. One variant, CRY1Δ11 c.1657+3A>C, is present in approximately 1% of Europeans, therefore standing out as a diagnostic and therapeutic marker. We showed by exome sequencing in an independent cohort of patients with combined ADHD and insomnia that 8 of 62 patients and 0 of 369 controls carried CRY1Δ11. Also, we identified a variant, CRY1Δ6 c.825+1G>A, that shows reduced affinity for BMAL1/CLOCK and causes an arrhythmic phenotype. Genotype-phenotype correlation analysis revealed that this variant segregated with ADHD and delayed sleep phase disorder (DSPD) in the affected family. Finally, we found in a phenome-wide association study involving 9438 unrelated adult Europeans that CRY1Δ11 was associated with major depressive disorder, insomnia, and anxiety. These results defined a distinctive group of circadian psychiatric phenotypes that we propose to designate as “circiatric” disorders.
O. Emre Onat, M. Ece Kars, Şeref Gül, Kaya Bilguvar, Yiming Wu, Ayşe Özhan, Cihan Aydın, A. Nazlı Başak, M. Allegra Trusso, Arianna Goracci, Chiara Fallerini, Alessandra Renieri, Jean-Laurent Casanova, Yuval Itan, Cem E. Atbaşoğlu, Meram C. Saka, İ. Halil Kavaklı, Tayfun Özçelik
Chronic infections can lead to carcinogenesis through inflammation-related mechanisms. Chronic infection of the human gastric mucosa with Helicobacter pylori is a well-known risk factor for gastric cancer. However, the mechanisms underlying H. pylori–induced gastric carcinogenesis are incompletely defined. We aimed to screen and clarify the functions of long noncoding RNAs (lncRNAs) that are differentially expressed in H. pylori–related gastric cancer. We found that lncRNA SNHG17 was upregulated by H. pylori infection and markedly increased the levels of double-strand breaks (DSBs). SNHG17 overexpression correlated with poor overall survival in patients with gastric cancer. The recruitment of NONO by overabundant nuclear SNHG17, along with the role of cytoplasmic SNHG17 as a decoy for miR-3909, which regulates Rad51 expression, shifted the DSB repair balance from homologous recombination toward nonhomologous end joining. Notably, during chronic H. pylori infection, SNHG17 knockdown inhibited chromosomal aberrations. Our findings suggest that spatially independent deregulation of the SNHG17/NONO and SNHG17/miR-3909/RING1/Rad51 pathways upon H. pylori infection promotes tumorigenesis in gastric cancer by altering the DNA repair system, which is critical for the maintenance of genomic stability. Upregulation of SNHG17 by H. pylori infection might be an undefined link between cancer and inflammation.
Taotao Han, Xiaohui Jing, Jiayu Bao, Lianmei Zhao, Aidong Zhang, Renling Miao, Hui Guo, Baoguo Zhou, Shang Zhang, Jiazeng Sun, Juan Shi
A common variant in the RAB27A gene in adults was recently found to be associated with the fractional exhaled nitric oxide level, a marker of eosinophilic airway inflammation. The small GTPase Rab27 is known to regulate intracellular vesicle traffic, although its role in allergic responses is unclear. We demonstrated that exophilin-5, a Rab27-binding protein, was predominantly expressed in both of the major IL-33 producers, lung epithelial cells, and the specialized IL-5 and IL-13 producers in the CD44hiCD62LloCXCR3lo pathogenic Th2 cell population in mice. Exophilin-5 deficiency increased stimulant-dependent damage and IL-33 secretion by lung epithelial cells. Moreover, it enhanced IL-5 and IL-13 production in response to TCR and IL-33 stimulation from a specific subset of pathogenic Th2 cells that expresses a high level of IL-33 receptor, which exacerbated allergic airway inflammation in a mouse model of asthma. Mechanistically, exophilin-5 regulates extracellular superoxide release, intracellular ROS production, and phosphoinositide 3-kinase activity by controlling intracellular trafficking of Nox2-containing vesicles, which seems to prevent the overactivation of pathogenic Th2 cells mediated by IL-33. This is the first report to our knowledge to establish the significance of the Rab27-related protein exophilin-5 in the development of allergic airway inflammation, and provides insights into the pathophysiology of asthma.
Katsuhide Okunishi, Hao Wang, Maho Suzukawa, Ray Ishizaki, Eri Kobayashi, Miho Kihara, Takaya Abe, Jun-ichi Miyazaki, Masafumi Horie, Akira Saito, Hirohisa Saito, Susumu Nakae, Tetsuro Izumi
BACKGROUND NK cells are activated by innate cytokines and viral ligands to kill virus-infected cells. These functions are enhanced during secondary immune responses and after vaccination by synergy with effector T cells and virus-specific antibodies. In human Ebola virus infection, clinical outcome is strongly associated with the initial innate cytokine response, but the role of NK cells has not been thoroughly examined.METHODS The novel 2-dose heterologous Adenovirus type 26.ZEBOV (Ad26.ZEBOV) and modified vaccinia Ankara-BN-Filo (MVA-BN-Filo) vaccine regimen is safe and provides specific immunity against Ebola glycoprotein, and is currently in phase 2 and 3 studies. Here, we analyzed NK cell phenotype and function in response to Ad26.ZEBOV, MVA-BN-Filo vaccination regimen and in response to in vitro Ebola glycoprotein stimulation of PBMCs isolated before and after vaccination.RESULTS We show enhanced NK cell proliferation and activation after vaccination compared with baseline. Ebola glycoprotein–induced activation of NK cells was dependent on accessory cells and TLR-4–dependent innate cytokine secretion (predominantly from CD14+ monocytes) and enriched within less differentiated NK cell subsets. Optimal NK cell responses were dependent on IL-18 and IL-12, whereas IFN-γ secretion was restricted by high concentrations of IL-10.CONCLUSION This study demonstrates the induction of NK cell effector functions early after Ad26.ZEBOV, MVA-BN-Filo vaccination and provides a mechanism for the activation and regulation of NK cells by Ebola glycoprotein.TRIAL REGISTRATION ClinicalTrials.gov NCT02313077.FUNDING United Kingdom Medical Research Council Studentship in Vaccine Research, Innovative Medicines Initiative 2 Joint Undertaking, EBOVAC (grant 115861) and Crucell Holland (now Janssen Vaccines and Prevention B.V.), European Union’s Horizon 2020 research and innovation programme and European Federation of Pharmaceutical Industries and Associations (EFPIA).
Helen R. Wagstaffe, Elizabeth A. Clutterbuck, Viki Bockstal, Jeroen N. Stoop, Kerstin Luhn, Macaya Douoguih, Georgi Shukarev, Matthew D. Snape, Andrew J. Pollard, Eleanor M. Riley, Martin R. Goodier