In this issue, Wang et al. report a human cellular model of Bardet-Biedl Syndrome (BBS), a ciliopathy characterized by hyperphagic obesity, using patient-specific induced pluripotent stem cell–derived (iPSC-derived) hypothalamic arcuate-like neurons. Their findings indicate that BBS proteins impact energy homeostasis by regulating cilia length and neuronal morphology, and by controlling key intracellular signaling pathways, such as insulin and leptin signaling. The cover image shows iPSC-derived neurons with a mutation in BBS10A stained for the neuronal markers TUJ1 (red) and MAP2 (green), with overlapping regions shown in yellow and Draq5-stained nuclei (blue).
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As part of the centennial celebration of insulin’s discovery, this review summarizes the current understanding of the genetics, pathogenesis, treatment, and outcomes in type 1 diabetes (T1D). T1D results from an autoimmune response that leads to destruction of the β cells in the pancreatic islet and requires lifelong insulin therapy. While much has been learned about T1D, it is now clear that there is considerable heterogeneity in T1D with regard to genetics, pathology, response to immune-based therapies, clinical course, and susceptibility to diabetes-related complications. This Review highlights knowledge gaps and opportunities to improve the understanding of T1D pathogenesis and outlines emerging therapies to treat or prevent T1D and reduce the burden of T1D.
Alvin C. Powers
Sickle cell disease (SCD) is a monogenic disorder characterized by recurrent episodes of severe bone pain, multi-organ failure, and early mortality. Although medical progress over the past several decades has improved clinical outcomes and offered cures for many affected individuals living in high-income countries, most SCD patients still experience substantial morbidity and premature death. Emerging technologies to manipulate somatic cell genomes and insights into the mechanisms of developmental globin gene regulation are generating potentially transformative approaches to cure SCD by autologous hematopoietic stem cell (HSC) transplantation. Key components of current approaches include ethical informed consent, isolation of patient HSCs, in vitro genetic modification of HSCs to correct the SCD mutation or circumvent its damaging effects, and reinfusion of the modified HSCs following myelotoxic bone marrow conditioning. Successful integration of these components into effective therapies requires interdisciplinary collaborations between laboratory researchers, clinical caregivers, and patients. Here we summarize current knowledge and research challenges for each key component, emphasizing that the best approaches have yet to be developed.
Phillip A. Doerfler, Akshay Sharma, Jerlym S. Porter, Yan Zheng, John F. Tisdale, Mitchell J. Weiss
Artificial intelligence has been applied to histopathology for decades, but the recent increase in interest is attributable to well-publicized successes in the application of deep-learning techniques, such as convolutional neural networks, for image analysis. Recently, generative adversarial networks (GANs) have provided a method for performing image-to-image translation tasks on histopathology images, including image segmentation. In this issue of the JCI, Koyuncu et al. applied GANs to whole-slide images of p16-positive oropharyngeal squamous cell carcinoma (OPSCC) to automate the calculation of a multinucleation index (MuNI) for prognostication in p16-positive OPSCC. Multivariable analysis showed that the MuNI was prognostic for disease-free survival, overall survival, and metastasis-free survival. These results are promising, as they present a prognostic method for p16-positive OPSCC and highlight methods for using deep learning to measure image biomarkers from histopathologic samples in an inherently explainable manner.
Toby C. Cornish
It has long been known that fatty acids can either adversely or positively affect insulin signaling in skeletal muscle, depending on chain length or saturation, and can therefore be primary drivers of systemic insulin sensitivity. However, the detailed mechanisms linking fatty acids to insulin signaling in skeletal muscle have been elusive. In this issue of the JCI, Ferrara et al. suggest a model whereby membrane lipid remodeling mediates skeletal muscle insulin sensitivity. The authors demonstrate that membrane glycerophospholipid fatty acid remodeling by lysophosphatidylcholine acyltransferase 3 (LPCAT3) in skeletal muscle from subjects with obesity was induced, suppressing insulin signaling and glucose tolerance. Loss or gain of LPCAT3 function in mouse models showed that Lpcat3 was both required and sufficient for high-fat diet–induced muscle insulin resistance. These results suggest that the physiochemical properties of muscle cell membranes may drive insulin sensitivity and, therefore, systemic glucose intolerance.
Michael J. Wolfgang
Loss-of-function mutations of SCN1A encoding the pore-forming α subunit of the NaV1.1 neuronal sodium channel cause a severe developmental epileptic encephalopathy, Dravet syndrome (DS). In this issue of the JCI, Chen, Luo, Gao, et al. describe a phenocopy for DS in mice deficient for posttranslational conjugation with neural precursor cell expressed, developmentally downregulated 8 (NEDD8) (neddylation), selectively engineered in inhibitory interneurons. Pursuing the possibility that this phenotype is also caused by loss of NaV1.1, Chen, Luo, Gao, and colleagues show that interneuron excitability and GABA release are impaired, NaV1.1 degradation rate is increased with a commensurate decrease of NaV1.1 protein, and NaV1.1 is a substrate for neddylation. These findings establish neddylation as a mechanism for stabilizing NaV1.1 subunits and suggest another pathomechanism for epileptic sodium channelopathy.
Stephen C. Cannon
Several coronavirus disease 2019 (COVID-19) studies have focused on neuropathology. In this issue of the JCI, Qin, Wu, and Chen et al. focused specifically on people whose acute infection lacked obvious neurological involvement. Severely infected patients showed abnormal gray matter volumes, white matter diffusion, and cerebral blood flow compared with healthy controls and those with mild infection. The data remain associative rather than mechanistic, but correlations with systemic immune markers suggest effects of inflammation, hypercoagulation, or other aspects of disease severity. Mechanistic research is warranted. Given the lack of obvious neurological symptoms, neurocognitive assessments were not performed, but the findings suggest that such assessments may be warranted in severely affected patients, even without obvious symptoms. Further, studying CNS involvement of other disorders with overlapping pathophysiologies such as inflammation, coagulation, hypoxia, or direct viral infection may reveal the causes for COVID-19–related neuropathology.
Amit Mahajan, Graeme F. Mason
Bardet-Biedl syndrome (BBS) is a syndromic ciliopathy that has obesity as a cardinal feature. BBS is caused by mutations in BBS genes. BBS proteins control primary cilia function, and BBS mutations therefore lead to dysfunctional primary cilia. Obesity in patients with BBS is mainly caused by hyperphagia due to dysregulated neuronal function in the brain, in particular in the hypothalamus. However, the mechanism by which mutations in BBS genes result in dysfunction in hypothalamic neurons is not well understood. In this issue of the JCI, Wang et al. used BBS and non-BBS patient–derived induced pluripotent stem cells to generate neurons and hypothalamic neurons. Using this human model system, the authors demonstrated that mutations in BBS genes affected primary cilia function, neuronal morphology, and signaling pathways regulating the function of hypothalamic neurons, which control energy homeostasis. This study provides important insights into the mechanisms of BBS-induced obesity.
Sandra Blaess, Dagmar Wachten
BACKGROUND Rejection is the primary barrier to broader implementation of vascularized composite allografts (VCAs), including face and limb transplants. The immunologic pathways activated in face transplant rejection have not been fully characterized.METHODS Using skin biopsies prospectively collected over 9 years from 7 face transplant patients, we studied rejection by gene expression profiling, histology, immunostaining, and T cell receptor sequencing.RESULTS Grade 1 rejection did not differ significantly from nonrejection, suggesting that it does not represent a pathologic state. In grade 2, there was a balanced upregulation of both proinflammatory T cell activation pathways and antiinflammatory checkpoint and immunomodulatory pathways, with a net result of no tissue injury. In grade 3, IFN-γ–driven inflammation, antigen-presenting cell activation, and infiltration of the skin by proliferative T cells bearing markers of antigen-specific activation and cytotoxicity tipped the balance toward tissue injury. Rejection of VCAs and solid organ transplants had both distinct and common features. VCA rejection was uniquely associated with upregulation of immunoregulatory genes, including SOCS1; induction of lipid antigen–presenting CD1 proteins; and infiltration by T cells predicted to recognize CD1b and CD1c.CONCLUSION Our findings suggest that the distinct features of VCA rejection reflect the unique immunobiology of skin and that enhancing cutaneous immunoregulatory networks may be a useful strategy in combatting rejection.Trial registration ClinicalTrials.gov NCT01281267.FUNDING Assistant Secretary of Defense and Health Affairs, through Reconstructive Transplant Research (W81XWH-17-1-0278, W81XWH-16-1-0647, W81XWH-16-1-0689, W81XWH-18-1-0784, W81XWH-1-810798); American Society of Transplantation’s Transplantation and Immunology Research Network Fellowship Research Grant; Plastic Surgery Foundation Fellowship from the American Society of Plastic Surgeons; Novo Nordisk Foundation (NNF15OC0014092); Lundbeck Foundation; Aage Bangs Foundation; A.P. Moller Foundation for the Advancement of Medical Science; NIH UL1 RR025758.
Thet Su Win, William J. Crisler, Beatrice Dyring-Andersen, Rachel Lopdrup, Jessica E. Teague, Qian Zhan, Victor Barrera, Shannan Ho Sui, Sotirios Tasigiorgos, Naoka Murakami, Anil Chandraker, Stefan G. Tullius, Bohdan Pomahac, Leonardo V. Riella, Rachael A. Clark
Aberrant lipid metabolism promotes the development of skeletal muscle insulin resistance, but the exact identity of lipid-mediated mechanisms relevant to human obesity remains unclear. A comprehensive lipidomic analysis of primary myocytes from individuals who were insulin-sensitive and lean (LN) or insulin-resistant with obesity (OB) revealed several species of lysophospholipids (lyso-PLs) that were differentially abundant. These changes coincided with greater expression of lysophosphatidylcholine acyltransferase 3 (LPCAT3), an enzyme involved in phospholipid transacylation (Lands cycle). Strikingly, mice with skeletal muscle–specific knockout of LPCAT3 (LPCAT3-MKO) exhibited greater muscle lysophosphatidylcholine/phosphatidylcholine, concomitant with improved skeletal muscle insulin sensitivity. Conversely, skeletal muscle–specific overexpression of LPCAT3 (LPCAT3-MKI) promoted glucose intolerance. The absence of LPCAT3 reduced phospholipid packing of cellular membranes and increased plasma membrane lipid clustering, suggesting that LPCAT3 affects insulin receptor phosphorylation by modulating plasma membrane lipid organization. In conclusion, obesity accelerates the skeletal muscle Lands cycle, whose consequence might induce the disruption of plasma membrane organization that suppresses muscle insulin action.
Patrick J. Ferrara, Xin Rong, J. Alan Maschek, Anthony R.P. Verkerke, Piyarat Siripoksup, Haowei Song, Thomas D. Green, Karthickeyan C. Krishnan, Jordan M. Johnson, John Turk, Joseph A. Houmard, Aldons J. Lusis, Micah J. Drummond, Joseph M. McClung, James E. Cox, Saame Raza Shaikh, Peter Tontonoz, William L. Holland, Katsuhiko Funai
The excitability of interneurons requires Nav1.1, the α subunit of the voltage-gated sodium channel. Nav1.1 deficiency and mutations reduce interneuron excitability, a major pathological mechanism for epilepsy syndromes. However, the regulatory mechanisms of Nav1.1 expression remain unclear. Here, we provide evidence that neddylation is critical to Nav1.1 stability. Mutant mice lacking Nae1, an obligatory component of the E1 ligase for neddylation, in parvalbumin-positive interneurons (PVINs) exhibited spontaneous epileptic seizures and premature death. Electrophysiological studies indicate that Nae1 deletion reduced PVIN excitability and GABA release and consequently increased the network excitability of pyramidal neurons (PyNs). Further analysis revealed a reduction in sodium-current density, not a change in channel property, in mutant PVINs and decreased Nav1.1 protein levels. These results suggest that insufficient neddylation in PVINs reduces Nav1.1 stability and thus the excitability of PVINs; the ensuing increased PyN activity causes seizures in mice. Consistently, Nav1.1 was found reduced by proteomic analysis that revealed abnormality in synapses and metabolic pathways. Our findings describe a role of neddylation in maintaining Nav1.1 stability for PVIN excitability and reveal what we believe is a new mechanism in the pathogenesis of epilepsy.
Wenbing Chen, Bin Luo, Nannan Gao, Haiwen Li, Hongsheng Wang, Lei Li, Wanpeng Cui, Lei Zhang, Dong Sun, Fang Liu, Zhaoqi Dong, Xiao Ren, Hongsheng Zhang, Huabo Su, Wen-Cheng Xiong, Lin Mei
Immune checkpoint blockade therapy has demonstrated promising clinical outcomes for multiple cancer types. However, the emergence of resistance as well as inadequate biomarkers for patient stratification have largely limited the clinical benefits. Here, we showed that tumors with high TYRO3 expression exhibited anti–programmed cell death protein 1/programmed death ligand 1 (anti–PD-1/PD-L1) resistance in a syngeneic mouse model and in patients who received anti–PD-1/PD-L1 therapy. Mechanistically, TYRO3 inhibited tumor cell ferroptosis triggered by anti–PD-1/PD-L1 and facilitated the development of a protumor microenvironment by reducing the M1/M2 macrophage ratio, resulting in resistance to anti–PD-1/PD-L1 therapy. Inhibition of TYRO3 promoted tumor ferroptosis and sensitized resistant tumors to anti–PD-1 therapy. Collectively, our findings suggest that TYRO3 could serve as a predictive biomarker for patient selection and a promising therapeutic target to overcome anti–PD-1/PD-L1 resistance.
Zhou Jiang, Seung-Oe Lim, Meisi Yan, Jennifer L. Hsu, Jun Yao, Yongkun Wei, Shih-Shin Chang, Hirohito Yamaguchi, Heng-Huan Lee, Baozhen Ke, Jung-Mao Hsu, Li-Chuan Chan, Gabriel N. Hortobagyi, Liuqing Yang, Chunru Lin, Dihua Yu, Mien-Chie Hung
Adoptive transfer of Tregs has been shown to improve alloengraftment in animal models. However, it is technically challenging to expand Tregs ex vivo for the purpose of infusing large numbers of cells in the clinic. We demonstrate an innovative approach to engineering an orthogonal IL-2/IL-2 receptor (IL-2R) pair, the parts of which selectively interact with each other, transmitting native IL-2 signals, but do not interact with the natural IL-2 or IL-2R counterparts, thereby enabling selective stimulation of target cells in vivo. Here, we introduced this orthogonal IL-2R into Tregs. Upon adoptive transfer in a murine mixed hematopoietic chimerism model, orthogonal IL-2 injection significantly promoted orthogonal IL-2R+Foxp3GFP+CD4+ cell proliferation without increasing other T cell subsets and facilitated donor hematopoietic cell engraftment followed by acceptance of heart allografts. Our data indicate that selective target cell stimulation enabled by the engineered orthogonal cytokine receptor improves Treg potential for the induction of organ transplantation tolerance.
Toshihito Hirai, Teresa L. Ramos, Po-Yu Lin, Federico Simonetta, Leon L. Su, Lora K. Picton, Jeanette Baker, Jian-Xin Lin, Peng Li, Kinya Seo, Juliane K. Lohmeyer, Sara Bolivar-Wagers, Melissa Mavers, Warren J. Leonard, Bruce R. Blazar, K. Christopher Garcia, Robert S. Negrin
Melanomas commonly undergo a phenotype switch, from a proliferative to an invasive state. Such tumor cell plasticity contributes to immunotherapy resistance; however, the mechanisms are not completely understood and thus are therapeutically unexploited. Using melanoma mouse models, we demonstrated that blocking the MNK1/2-eIF4E axis inhibited melanoma phenotype switching and sensitized melanoma to anti–PD-1 immunotherapy. We showed that phospho-eIF4E–deficient murine melanomas expressed high levels of melanocytic antigens, with similar results verified in patient melanomas. Mechanistically, we identified phospho-eIF4E–mediated translational control of NGFR, a critical effector of phenotype switching. Genetic ablation of phospho-eIF4E reprogrammed the immunosuppressive microenvironment, exemplified by lowered production of inflammatory factors, decreased PD-L1 expression on dendritic cells and myeloid-derived suppressor cells, and increased CD8+ T cell infiltrates. Finally, dual blockade of the MNK1/2-eIF4E axis and the PD-1/PD-L1 immune checkpoint demonstrated efficacy in multiple melanoma models regardless of their genomic classification. An increase in the presence of intratumoral stem-like TCF1+PD-1+CD8+ T cells, a characteristic essential for durable antitumor immunity, was detected in mice given a MNK1/2 inhibitor and anti–PD-1 therapy. Using MNK1/2 inhibitors to repress phospho-eIF4E thus offers a strategy to inhibit melanoma plasticity and improve response to anti–PD-1 immunotherapy.
Fan Huang, Christophe Gonçalves, Margarita Bartish, Joelle Rémy-Sarrazin, Mark E. Issa, Brendan Cordeiro, Qianyu Guo, Audrey Emond, Mikhael Attias, William Yang, Dany Plourde, Jie Su, Marina Godoy Gimeno, Yao Zhan, Alba Galán, Tomasz Rzymski, Milena Mazan, Magdalena Masiejczyk, Jacek Faber, Elie Khoury, Alexandre Benoit, Natascha Gagnon, David Dankort, Fabrice Journe, Ghanem E. Ghanem, Connie M. Krawczyk, H. Uri Saragovi, Ciriaco A. Piccirillo, Nahum Sonenberg, Ivan Topisirovic, Christopher E. Rudd, Wilson H. Miller Jr., Sonia V. del Rincón
To define the contribution of CD8+ T cell responses to control of SIV reactivation during and following antiretroviral therapy (ART), we determined the effect of long-term CD8+ T cell depletion using a rhesusized anti-CD8β monoclonal antibody on barcoded SIVmac239 dynamics on stable ART and after ART cessation in rhesus macaques (RMs). Among the RMs with full CD8+ T cell depletion in both blood and tissue, there were no significant differences in the frequency of viral blips in plasma, the number of SIV RNA+ cells and the average number of RNA copies/infected cell in tissue, and levels of cell-associated SIV RNA and DNA in blood and tissue relative to control-treated RMs during ART. Upon ART cessation, both CD8+ T cell–depleted and control RMs rebounded in fewer than 12 days, with no difference in the time to viral rebound or in either the number or growth rate of rebounding SIVmac239M barcode clonotypes. However, effectively CD8+ T cell–depleted RMs showed a stable, approximately 2-log increase in post-ART plasma viremia relative to controls. These results indicate that while potent antiviral CD8+ T cell responses can develop during ART-suppressed SIV infection, these responses effectively intercept post-ART SIV rebound only after systemic viral replication, too late to limit reactivation frequency or the early spread of reactivating SIV reservoirs.
Afam A. Okoye, Derick D. Duell, Yoshinori Fukazawa, Benjamin Varco-Merth, Alejandra Marenco, Hannah Behrens, Morgan Chaunzwa, Andrea N. Selseth, Roxanne M. Gilbride, Jason Shao, Paul T. Edlefsen, Romas Geleziunas, Mykola Pinkevych, Miles P. Davenport, Kathleen Busman-Sahay, Michael Nekorchuk, Haesun Park, Jeremy Smedley, Michael K. Axthelm, Jacob D. Estes, Scott G. Hansen, Brandon F. Keele, Jeffery D. Lifson, Louis J. Picker
In humans receiving intestinal transplantation (ITx), long-term multilineage blood chimerism often develops. Donor T cell macrochimerism (≥4%) frequently occurs without graft-versus-host disease (GVHD) and is associated with reduced rejection. Here we demonstrate that patients with macrochimerism had high graft-versus-host (GvH) to host-versus-graft (HvG) T cell clonal ratios in their allografts. These GvH clones entered the circulation, where their peak levels were associated with declines in HvG clones early after transplant, suggesting that GvH reactions may contribute to chimerism and control HvG responses without causing GVHD. Consistently, donor-derived T cells, including GvH clones, and CD34+ hematopoietic stem and progenitor cells (HSPCs) were simultaneously detected in the recipients’ BM more than 100 days after transplant. Individual GvH clones appeared in ileal mucosa or PBMCs before detection in recipient BM, consistent with an intestinal mucosal origin, where donor GvH-reactive T cells expanded early upon entry of recipient APCs into the graft. These results, combined with cytotoxic single-cell transcriptional profiles of donor T cells in recipient BM, suggest that tissue-resident GvH-reactive donor T cells migrated into the recipient circulation and BM, where they destroyed recipient hematopoietic cells through cytolytic effector functions and promoted engraftment of graft-derived HSPCs that maintain chimerism. These mechanisms suggest an approach to achieving intestinal allograft tolerance.
Jianing Fu, Julien Zuber, Brittany Shonts, Aleksandar Obradovic, Zicheng Wang, Kristjana Frangaj, Wenzhao Meng, Aaron M. Rosenfeld, Elizabeth E. Waffarn, Peter Liou, Sai-ping Lau, Thomas M. Savage, Suxiao Yang, Kortney Rogers, Nichole M. Danzl, Shilpa Ravella, Prakash Satwani, Alina Iuga, Siu-hong Ho, Adam Griesemer, Yufeng Shen, Eline T. Luning Prak, Mercedes Martinez, Tomoaki Kato, Megan Sykes
X-linked adrenoleukodystrophy (ALD) is a progressive neurodegenerative disease caused by mutations in ABCD1, the peroxisomal very long–chain fatty acid (VLCFA) transporter. ABCD1 deficiency results in accumulation of saturated VLCFAs. A drug screen using a phenotypic motor assay in a zebrafish ALD model identified chloroquine as the top hit. Chloroquine increased expression of stearoyl-CoA desaturase-1 (scd1), the enzyme mediating fatty acid saturation status, suggesting that a shift toward monounsaturated fatty acids relieved toxicity. In human ALD fibroblasts, chloroquine also increased SCD1 levels and reduced saturated VLCFAs. Conversely, pharmacological inhibition of SCD1 expression led to an increase in saturated VLCFAs, and CRISPR knockout of scd1 in zebrafish mimicked the motor phenotype of ALD zebrafish. Importantly, saturated VLCFAs caused ER stress in ALD fibroblasts, whereas monounsaturated VLCFA did not. In parallel, we used liver X receptor (LXR) agonists to increase SCD1 expression, causing a shift from saturated toward monounsaturated VLCFA and normalizing phospholipid profiles. Finally, Abcd1–/y mice receiving LXR agonist in their diet had VLCFA reductions in ALD-relevant tissues. These results suggest that metabolic rerouting of saturated to monounsaturated VLCFAs may alleviate lipid toxicity, a strategy that may be beneficial in ALD and other peroxisomal diseases in which VLCFAs play a key role.
Quentin Raas, Malu-Clair van de Beek, Sonja Forss-Petter, Inge M.E. Dijkstra, Abigail Deschiffart, Briana C. Freshner, Tamara J. Stevenson, Yorrick R.J. Jaspers, Liselotte Nagtzaam, Ronald J.A. Wanders, Michel van Weeghel, Joo-Yeon Engelen-Lee, Marc Engelen, Florian Eichler, Johannes Berger, Joshua L. Bonkowsky, Stephan Kemp
Inhibitors of factor VIII (FVIII) remain the most challenging complication of FVIII protein replacement therapy in hemophilia A (HA). Understanding the mechanisms that guide FVIII-specific B cell development could help identify therapeutic targets. The B cell–activating factor (BAFF) cytokine family is a key regulator of B cell differentiation in normal homeostasis and immune disorders. Thus, we used patient samples and mouse models to investigate the potential role of BAFF in modulating FVIII inhibitors. BAFF levels were elevated in pediatric and adult HA inhibitor patients and decreased to levels similar to those of noninhibitor controls after successful immune tolerance induction (ITI). Moreover, elevations in BAFF levels were seen in patients who failed to achieve FVIII tolerance with anti-CD20 antibody–mediated B cell depletion. In naive HA mice, prophylactic anti-BAFF antibody therapy prior to FVIII immunization prevented inhibitor formation and this tolerance was maintained despite FVIII exposure after immune reconstitution. In preimmunized HA mice, combination therapy with anti-CD20 and anti-BAFF antibodies dramatically reduced FVIII inhibitors via inhibition of FVIII-specific plasma cells. Our data suggest that BAFF may regulate the generation and maintenance of FVIII inhibitors and/or anti-FVIII B cells. Finally, anti-CD20/anti-BAFF combination therapy may be clinically useful for ITI.
Bhavya S. Doshi, Jyoti Rana, Giancarlo Castaman, Mostafa A. Shaheen, Radoslaw Kaczmarek, John S.S. Butterfield, Shannon L. Meeks, Cindy Leissinger, Moanaro Biswas, Valder R. Arruda
Although cancer cells are frequently faced with a nutrient- and oxygen-poor microenvironment, elevated hexosamine-biosynthesis pathway (HBP) activity and protein O-GlcNAcylation (a nutrient sensor) contribute to rapid growth of tumor and are emerging hallmarks of cancer. Inhibiting O-GlcNAcylation could be a promising anticancer strategy. The gluconeogenic enzyme phosphoenolpyruvate carboxykinase 1 (PCK1) is downregulated in hepatocellular carcinoma (HCC). However, little is known about the potential role of PCK1 in enhanced HBP activity and HCC carcinogenesis under glucose-limited conditions. In this study, PCK1 knockout markedly enhanced the global O-GlcNAcylation levels under low-glucose conditions. Mechanistically, metabolic reprogramming in PCK1-loss hepatoma cells led to oxaloacetate accumulation and increased de novo uridine triphosphate synthesis contributing to uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) biosynthesis. Meanwhile, deletion of PCK1 also resulted in AMPK-GFAT1 axis inactivation, promoting UDP-GlcNAc synthesis for elevated O-GlcNAcylation. Notably, lower expression of PCK1 promoted CHK2 threonine 378 O-GlcNAcylation, counteracting its stability and dimer formation, increasing CHK2-dependent Rb phosphorylation and HCC cell proliferation. Moreover, aminooxyacetic acid hemihydrochloride and 6-diazo-5-oxo-L-norleucine blocked HBP-mediated O-GlcNAcylation and suppressed tumor progression in liver-specific Pck1-knockout mice. We reveal a link between PCK1 depletion and hyper-O-GlcNAcylation that underlies HCC oncogenesis and suggest therapeutic targets for HCC that act by inhibiting O-GlcNAcylation.
Jin Xiang, Chang Chen, Rui Liu, Dongmei Gou, Lei Chang, Haijun Deng, Qingzhu Gao, Wanjun Zhang, Lin Tuo, Xuanming Pan, Li Liang, Jie Xia, Luyi Huang, Ke Yao, Bohong Wang, Zeping Hu, Ailong Huang, Kai Wang, Ni Tang
Efferocytosis, the process through which apoptotic cells (ACs) are cleared through actin-mediated engulfment by macrophages, prevents secondary necrosis, suppresses inflammation, and promotes resolution. Impaired efferocytosis drives the formation of clinically dangerous necrotic atherosclerotic plaques, the underlying etiology of coronary artery disease (CAD). An intron of the gene encoding PHACTR1 contains rs9349379 (A>G), a common variant associated with CAD. As PHACTR1 is an actin-binding protein, we reasoned that if the rs9349379 risk allele G causes lower PHACTR1 expression in macrophages, it might link the risk allele to CAD via impaired efferocytosis. We show here that rs9349379-G/G was associated with lower levels of PHACTR1 and impaired efferocytosis in human monocyte–derived macrophages and human atherosclerotic lesional macrophages compared with rs9349379-A/A. Silencing PHACTR1 in human and mouse macrophages compromised AC engulfment, and Western diet–fed Ldlr–/– mice in which hematopoietic Phactr1 was genetically targeted showed impaired lesional efferocytosis, increased plaque necrosis, and thinner fibrous caps — all signs of vulnerable plaques in humans. Mechanistically, PHACTR1 prevented dephosphorylation of myosin light chain (MLC), which was necessary for AC engulfment. In summary, rs9349379-G lowered PHACTR1, which, by lowering phospho-MLC, compromised efferocytosis. Thus, rs9349379-G may contribute to CAD risk, at least in part, by impairing atherosclerotic lesional macrophage efferocytosis.
Canan Kasikara, Maaike Schilperoort, Brennan Gerlach, Chenyi Xue, Xiaobo Wang, Ze Zheng, George Kuriakose, Bernhard Dorweiler, Hanrui Zhang, Gabrielle Fredman, Danish Saleheen, Muredach P. Reilly, Ira Tabas
BACKGROUND Patients with p16+ oropharyngeal squamous cell carcinoma (OPSCC) are potentially cured with definitive treatment. However, there are currently no reliable biomarkers of treatment failure for p16+ OPSCC. Pathologist-based visual assessment of tumor cell multinucleation (MN) has been shown to be independently prognostic of disease-free survival (DFS) in p16+ OPSCC. However, its quantification is time intensive, subjective, and at risk of interobserver variability.METHODS We present a deep-learning–based metric, the multinucleation index (MuNI), for prognostication in p16+ OPSCC. This approach quantifies tumor MN from digitally scanned H&E-stained slides. Representative H&E-stained whole-slide images from 1094 patients with previously untreated p16+ OPSCC were acquired from 6 institutions for optimization and validation of the MuNI.RESULTS The MuNI was prognostic for DFS, overall survival (OS), or distant metastasis–free survival (DMFS) in p16+ OPSCC, with HRs of 1.78 (95% CI: 1.37–2.30), 1.94 (1.44–2.60), and 1.88 (1.43–2.47), respectively, independent of age, smoking status, treatment type, or tumor and lymph node (T/N) categories in multivariable analyses. The MuNI was also prognostic for DFS, OS, and DMFS in patients with stage I and stage III OPSCC, separately.CONCLUSION MuNI holds promise as a low-cost, tissue-nondestructive, H&E stain–based digital biomarker test for counseling, treatment, and surveillance of patients with p16+ OPSCC. These data support further confirmation of the MuNI in prospective trials.FUNDING National Cancer Institute (NCI), NIH; National Institute for Biomedical Imaging and Bioengineering, NIH; National Center for Research Resources, NIH; VA Merit Review Award from the US Department of VA Biomedical Laboratory Research and Development Service; US Department of Defense (DOD) Breast Cancer Research Program Breakthrough Level 1 Award; DOD Prostate Cancer Idea Development Award; DOD Lung Cancer Investigator-Initiated Translational Research Award; DOD Peer-Reviewed Cancer Research Program; Ohio Third Frontier Technology Validation Fund; Wallace H. Coulter Foundation Program in the Department of Biomedical Engineering; Clinical and Translational Science Award (CTSA) program, Case Western Reserve University; NCI Cancer Center Support Grant, NIH; Career Development Award from the US Department of VA Clinical Sciences Research and Development Program; Dan L. Duncan Comprehensive Cancer Center Support Grant, NIH; and Computational Genomic Epidemiology of Cancer Program, Case Comprehensive Cancer Center. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH, the US Department of VA, the DOD, or the US Government.
Can F. Koyuncu, Cheng Lu, Kaustav Bera, Zelin Zhang, Jun Xu, Paula Toro, German Corredor, Deborah Chute, Pingfu Fu, Wade L. Thorstad, Farhoud Faraji, Justin A. Bishop, Mitra Mehrad, Patricia D. Castro, Andrew G. Sikora, Lester D.R. Thompson, R.D. Chernock, Krystle A. Lang Kuhs, Jingqin Luo, Vlad Sandulache, David J. Adelstein, Shlomo Koyfman, James S. Lewis Jr., Anant Madabhushi
Dysregulated immune profiles have been described in symptomatic patients infected with SARS-CoV-2. Whether the reported immune alterations are specific to SARS-CoV-2 infection or also triggered by other acute illnesses remains unclear. We performed flow cytometry analysis on fresh peripheral blood from a consecutive cohort of (a) patients hospitalized with acute SARS-CoV-2 infection, (b) patients of comparable age and sex hospitalized for another acute disease (SARS-CoV-2 negative), and (c) healthy controls. Using both data-driven and hypothesis-driven analyses, we found several dysregulations in immune cell subsets (e.g., decreased proportion of T cells) that were similarly associated with acute SARS-CoV-2 infection and non–COVID-19-related acute illnesses. In contrast, we identified specific differences in myeloid and lymphocyte subsets that were associated with SARS-CoV-2 status (e.g., elevated proportion of ICAM-1+ mature/activated neutrophils, ALCAM+ monocytes, and CD38+CD8+ T cells). A subset of SARS-CoV-2–specific immune alterations correlated with disease severity, disease outcome at 30 days, and mortality. Our data provide an understanding of the immune dysregulation specifically associated with SARS-CoV-2 infection among acute care hospitalized patients. Our study lays the foundation for the development of specific biomarkers to stratify SARS-CoV-2–positive patients at risk of unfavorable outcomes and to uncover candidate molecules to investigate from a therapeutic perspective.
Rose-Marie Rébillard, Marc Charabati, Camille Grasmuck, Abdelali Filali-Mouhim, Olivier Tastet, Nathalie Brassard, Audrey Daigneault, Lyne Bourbonnière, Sai Priya Anand, Renaud Balthazard, Guillaume Beaudoin-Bussières, Romain Gasser, Mehdi Benlarbi, Ana Carmena Moratalla, Yves Carpentier Solorio, Marianne Boutin, Negar Farzam-kia, Jade Descôteaux-Dinelle, Antoine Philippe Fournier, Elizabeth Gowing, Annemarie Laumaea, Hélène Jamann, Boaz Lahav, Guillaume Goyette, Florent Lemaître, Victoria Hannah Mamane, Jérémie Prévost, Jonathan Richard, Karine Thai, Jean-François Cailhier, Nicolas Chomont, Andrés Finzi, Michaël Chassé, Madeleine Durand, Nathalie Arbour, Daniel E. Kaufmann, Alexandre Prat, Catherine Larochelle
A(H3N2) influenza vaccine effectiveness (VE) was low during the 2016–19 seasons and varied by age. We analyzed neutralizing antibody responses to egg- and cell-propagated A(H3N2) vaccine and circulating viruses following vaccination in 375 individuals (aged 7 months to 82 years) across all vaccine-eligible age groups in 3 influenza seasons. Antibody responses to cell- versus egg-propagated vaccine viruses were significantly reduced due to the egg-adapted changes T160K, D225G, and L194P in the vaccine hemagglutinins. Vaccine egg adaptation had a differential impact on antibody responses across the different age groups. Immunologically naive children immunized with egg-adapted vaccines mostly mounted antibodies targeting egg-adapted epitopes, whereas those previously primed with infection produced broader responses even when vaccinated with egg-based vaccines. In the elderly, repeated boosts of vaccine egg-adapted epitopes significantly reduced antibody responses to the WT cell–grown viruses. Analysis with reverse genetic viruses suggested that the response to each egg-adapted substitution varied by age. No differences in antibody responses were observed between male and female vaccinees. Here, the combination of age-specific responses to vaccine egg-adapted substitutions, diverse host immune priming histories, and virus antigenic drift affected antibody responses following vaccination and may have led to the low and variable VE against A(H3N2) viruses across different age groups.
Feng Liu, F. Liaini Gross, Stacie N. Jefferson, Crystal Holiday, Yaohui Bai, Li Wang, Bin Zhou, Min Z. Levine
Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder caused by mutations in genes encoding components of the primary cilium and is characterized by hyperphagic obesity. To investigate the molecular basis of obesity in human BBS, we developed a cellular model of BBS using induced pluripotent stem cell–derived (iPSC-derived) hypothalamic arcuate-like neurons. BBS mutations BBS1M390R and BBS10C91fsX95 did not affect neuronal differentiation efficiency but caused morphological defects, including impaired neurite outgrowth and longer primary cilia. Single-cell RNA sequencing of BBS1M390R hypothalamic neurons identified several downregulated pathways, including insulin and cAMP signaling and axon guidance. Additional studies demonstrated that BBS1M390R and BBS10C91fsX95 mutations impaired insulin signaling in both human fibroblasts and iPSC-derived neurons. Overexpression of intact BBS10 fully restored insulin signaling by restoring insulin receptor tyrosine phosphorylation in BBS10C91fsX95 neurons. Moreover, mutations in BBS1 and BBS10 impaired leptin-mediated p-STAT3 activation in iPSC-derived hypothalamic neurons. Correction of the BBS mutation by CRISPR rescued leptin signaling. POMC expression and neuropeptide production were decreased in BBS1M390R and BBS10C91fsX95 iPSC–derived hypothalamic neurons. In the aggregate, these data provide insights into the anatomic and functional mechanisms by which components of the BBSome in CNS primary cilia mediate effects on energy homeostasis.
Liheng Wang, Yang Liu, George Stratigopoulos, Sunil Panigrahi, Lina Sui, Yiying Zhang, Charles A. Leduc, Hannah J. Glover, Maria Caterina De Rosa, Lisa C. Burnett, Damian J. Williams, Linshan Shang, Robin Goland, Stephen H. Tsang, Sharon Wardlaw, Dieter Egli, Deyou Zheng, Claudia A. Doege, Rudolph L. Leibel
Small ubiquitin-like modifier (SUMO) binding (termed SUMOylation) emerged as the inducer for the sorting of bioactive molecules into extracellular vesicles (EVs), triggering lymphangiogenesis and further driving tumor lymph node (LN) metastasis, but the precise mechanisms remain largely unclear. Here, we show that bladder cancer (BCa) cell–secreted EVs mediated intercellular communication with human lymphatic endothelial cells (HLECs) through transmission of the long noncoding RNA ELNAT1 and promoted lymphangiogenesis and LN metastasis in a SUMOylation-dependent manner in both cultured BCa cell lines and mouse models. Mechanistically, ELNAT1 induced UBC9 overexpression to catalyze the SUMOylation of hnRNPA1 at the lysine 113 residue, which mediated recognition of ELNAT1 by the endosomal sorting complex required for transport (ESCRT) and facilitated its packaging into EVs. EV-mediated ELNAT1 was specifically transmitted into HLECs and epigenetically activated SOX18 transcription to induce lymphangiogenesis. Importantly, blocking the SUMOylation of tumor cells by downregulating UBC9 expression markedly reduced lymphatic metastasis in EV-mediated, ELNAT1-treated BCa in vivo. Clinically, EV-mediated ELNAT1 was correlated with LN metastasis and a poor prognosis for patients with BCa. These findings highlight a molecular mechanism whereby the EV-mediated ELNAT1/UBC9/SOX18 regulatory axis promotes lymphangiogenesis and LN metastasis in BCa in a SUMOylation-dependent manner and implicate ELNAT1 as an attractive therapeutic target for LN metastatic BCa.
Changhao Chen, Hanhao Zheng, Yuming Luo, Yao Kong, Mingjie An, Yuting Li, Wang He, Bowen Gao, Yue Zhao, Hao Huang, Jian Huang, Tianxin Lin
BACKGROUND The coronavirus disease 2019 (COVID-19) rapidly progressed to a global pandemic. Although some patients totally recover from COVID-19 pneumonia, the disease’s long-term effects on the brain still need to be explored.METHODS We recruited 51 patients with 2 subtypes of COVID-19 (19 mild and 32 severe) with no specific neurological manifestations at the acute stage and no obvious lesions on the conventional MRI 3 months after discharge. Changes in gray matter morphometry, cerebral blood flow (CBF), and white matter (WM) microstructure were investigated using MRI. The relationship between brain imaging measurements and inflammation markers was further analyzed.RESULTS Compared with healthy controls, the decrease in cortical thickness/CBF and the changes in WM microstructure were more severe in patients with severe disease than in those with mild disease, especially in the frontal and limbic systems. Furthermore, changes in brain microstructure, CBF, and tract parameters were significantly correlated (P < 0.05) with the inflammatory markers C-reactive protein, procalcitonin, and interleukin 6.CONCLUSION Indirect injury related to inflammatory storm may damage the brain, altering cerebral volume, CBF, and WM tracts. COVID-19–related hypoxemia and dysfunction of vascular endothelium may also contribute to neurological changes. The abnormalities in these brain areas need to be monitored during recovery, which could help clinicians understand the potential neurological sequelae of COVID-19.FUNDING Natural Science Foundation of China.
Yuanyuan Qin, Jinfeng Wu, Tao Chen, Jia Li, Guiling Zhang, Di Wu, Yiran Zhou, Ning Zheng, Aoling Cai, Qin Ning, Anne Manyande, Fuqiang Xu, Jie Wang, Wenzhen Zhu