Acute graft-versus-host disease (GVHD) is initially triggered by alloreactive T cells, which damage peripheral tissues and lymphoid organs. Subsequent transition to chronic GVHD involves the emergence of autoimmunity although the underlying mechanisms driving this process are unclear. Here, we tested the hypothesis that acute GVHD blocks peripheral tolerance of autoreactive T cells by impairing lymph node (LN) display of peripheral tissue-restricted antigens (PTA). At the initiation of GVHD, LN fibroblastic reticular cells (FRC) rapidly reduced expression of genes regulated by DEAF1, an Autoimmune Regulator-like transcription factor required for intra-nodal expression of PTA. Subsequently, GVHD led to the selective elimination of the FRC population, and blocked the repair pathways required for its regeneration. We used a transgenic mouse model to show that the loss of presentation of an intestinal PTA by FRC during GVHD resulted in the activation of auto-aggressive T cells and gut injury. Finally, we show that FRC normally expressed a unique PTA gene signature that was highly enriched for genes expressed in the target organs affected by chronic GVHD. In conclusion, acute GVHD damages and prevents repair of the FRC network, thus disabling an essential platform for purging auto-reactive T cells from the repertoire.
Simone Dertschnig, Pamela Evans, Pedro Santos e Sousa, Teresa Manzo, Ivana R. Ferrer, Hans J. Stauss, Clare L. Bennett, Ronjon Chakraverty
Aberrant expression of the cardiac gap junction protein connexin-43 (Cx43) has been suggested to play a role in the development of cardiac disease in the mdx mouse model of Duchenne muscular dystrophy (DMD), however a mechanistic understanding of this association is lacking. Here, we identified a reduction of phosphorylation of Cx43 serines S325/S328/S330 in human and mouse DMD hearts. We hypothesized that hypo-phosphorylation of Cx43 serine-triplet triggers pathological Cx43 redistribution to the lateral sides of cardiomyocytes (remodeling). Therefore, we generated knock-in mdx mice in which the Cx43 serine-triplet was replaced with either phospho-mimicking glutamic acids (mdxS3E) or non-phosphorylatable alanines (mdxS3A). The mdxS3E but not mdxS3A mice were resistant to Cx43 remodeling with a corresponding reduction of Cx43 hemichannel activity. MdxS3E cardiomyocytes displayed improved intracellular Ca2+ signaling and a reduction of NOX2/reactive oxygen species (ROS) production. Furthermore, mdxS3E mice were protected against inducible arrhythmias, related lethality and the development of cardiomyopathy. Inhibition of microtubule polymerization by colchicine reduced both NOX2/ROS and oxidized CaMKII, increased S325/S328/S330 phosphorylation and prevented Cx43 remodeling in mdx hearts. Together, these results demonstrate a mechanism of dystrophic Cx43-remodeling and suggest that targeting Cx43 may be a therapeutic strategy to prevent heart dysfunction and arrhythmias in DMD patients.
Eric Himelman, Mauricio A. Lillo, Julie Nouet, J. Patrick Gonzalez, Qingshi Zhao, Lai-Hua Xie, Hong Li, Tong Liu, Xander H.T. Wehrens, Paul D. Lampe, Glenn I. Fishman, Natalia Shirokova, Jorge E. Contreras, Diego Fraidenraich
Bruton tyrosine kinase (BTK) is present in a wide variety of cells and may thus have important non-B cell functions. Here we explored the function of this kinase in macrophages with studies of its regulation of the NLRP3 inflammasome. We found that bone marrow-derived macrophages (BMDMs) from BTK-deficient mice or monocytes from X-linked agammaglobulinemia patients exhibit increased NLRP3 inflammasome activity; this was also the case with BMDMs exposed to low doses of BTK inhibitor such as ibrutinib and monocytes from chronic lymphocytic leukemia patients being treated with ibrutinib. In mechanistic studies, we found that BTK binds to NLRP3 during the priming phase of inflammasome activation and in doing so inhibits LPS/nigericin-induced assembly of the NLRP3 inflammasome during the activation phase of inflammasome activation. This inhibitory effect was caused by BTK inhibition of PP2A-mediated dephosphorylation of Ser5 in the pyrin domain of NLRP3. Finally, we showed that BTK-deficient mice are subject to severe experimental colitis and such colitis is normalized by administration of anti-IL-β or an inhibitor of IL-1β signaling, anakinra. Together, these studies strongly suggest that BTK functions as a physiologic inhibitor of NLRP3 inflammasome activation; they thereby explain the fact that XLA patients are prone to develop Crohn’s disease.
Liming Mao, Atsushi Kitani, Eitaro Hiejima, Kim Montgomery-Recht, Wenchang Zhou, Ivan Fuss, Adrian Wiestner, Warren Strober
Hematopoietic stem cell (HSC) attrition is considered the key event underlying progressive bone marrow failure (BMF) in Fanconi anemia (FA), the most frequent inherited BMF disorder in humans. However, despite major advances, how the cellular, biochemical and molecular alterations reported in FA lead to HSC exhaustion remains poorly understood. Here, we demonstrated in human and mouse cells that loss-of-function of FANCA or FANCC, products of two genes affecting more than 80% of FA patients worldwide, is associated with constitutive expression of the transcription factor Microphthalmia (MiTF) through the cooperative, unscheduled activation of several stress signaling pathways, including the SMAD2/3, p38MAPK, NF-kB and AKT cascades. We validated the unrestrained Mitf expression downstream of p38 in Fanca-/- mice, which display hallmarks of hematopoietic stress, including loss of HSC quiescence, DNA damage accumulation in HSCs and reduced HSC repopulation capacity. Importantly, we demonstrated that shRNA-mediated downregulation of Mitf expression or inhibition of p38 signaling rescued HSC quiescence and prevented DNA damage accumulation. Our data support the hypothesis that HSC attrition in FA is the consequence of defects in the DNA damage response combined with chronic activation of otherwise transiently activated signaling pathways, which jointly prevent the recovery of HSC quiescence.
Alessia Oppezzo, Julie Bourseguin, Emilie Renaud, Patrycja Pawlikowska, Filippo Rosselli
Oncogenic KRAS is a major driver in lung adenocarcinoma (LUAD) that has yet to be therapeutically conquered. Here we report that the SLC7A11/glutathione axis displays metabolic synthetic lethality with oncogenic KRAS. Through metabolomics approaches, we found that mutationally activated KRAS strikingly increased the intracellular cystine level and glutathione biosynthesis. SLC7A11, a cystine/glutamate antiporter conferring specificity for cystine uptake, was overexpressed in patients with KRAS-mutant LUAD and showed positive association with tumor progression. Furthermore, SLC7A11 inhibition either by genetic depletion or pharmacological inhibition by sulfasalazine resulted in selective killing across a panel of KRAS-mutant cancer cells in vitro and tumor growth inhibition in vivo, suggesting the functionality and specificity of SLC7A11 as a therapeutic target. Importantly, we further identified a potent SLC7A11 inhibitor, HG106 that markedly decreased cystine uptake and intracellular glutathione biosynthesis. Furthermore, HG106 exhibited selective cytotoxicity towards KRAS-mutant cells by increasing oxidative stress- and endoplasmic reticulum stress-mediated cell apoptosis. Of note, treatment of KRAS-mutant LUAD with HG106 in several lung cancer preclinical mouse models led to marked tumor suppression and prolonged mouse survival. Overall, our findings reveal that KRAS-mutant LUAD cells are vulnerable to SLC7A11 inhibition, providing promising therapeutic approaches to the treatment of this currently incurable disease.
Kewen Hu, Kun Li, Jing Lv, Jie Feng, Jing Chen, Haigang Wu, Feixiong Cheng, Wenhao Jiang, Jieqiong Wang, Haixiang Pei, Paul J. Chiao, Zhenyu Cai, Yihua Chen, Mingyao Liu, Xiufeng Pang
Deficits in social interaction (SI) are a core symptom of Autism Spectrum Disorders (ASD), however treatments for social deficits are notably lacking. Elucidating brain circuits and neuromodulatory signaling systems that regulate sociability could facilitate a deeper understanding of ASD pathophysiology and reveal novel treatments for ASD. Here we found that in vivo optogenetic activation of the basolateral amygdala-nucleus accumbens (BLA-NAc) glutamatergic circuit reduced SI and increased social avoidance in mice. Furthermore, we found that 2-arachidonoylglycerol (2-AG) endocannabinoid (eCB) signaling reduced BLA-NAc glutamatergic activity, and that pharmacological 2-AG augmentation via administration of JZL184 blocked SI deficits associated with in vivo BLA-NAc stimulation. Additionally, optogenetic inhibition of the BLA-NAc circuit significantly increased SI in the Shank3B-/-, an ASD model with substantial SI impairment, without affecting SI in wild-type mice. Finally, we demonstrated that JZL184 delivered systemically or directly to the NAc also normalized SI deficits in Shank3B-/-mice, while ex vivo JZL184 application corrected aberrant NAc excitatory and inhibitory neurotransmission and reduced BLA-NAc-elicited feedforward inhibition of NAc neurons in Shank3B-/- mice. These data reveal circuit-level and neuromodulatory mechanisms regulating social function relevant to ASD and suggest 2-AG augmentation could reduce social deficits via modulation of excitatory and inhibitory neurotransmission in the NAc.
Oakleigh M. Folkes, Rita Báldi, Veronika Kondev, David J. Marcus, Nolan D. Hartley, Brandon D. Turner, Jade K. Ayers, Jordan J. Baechle, Maya P. Misra, Megan Altemus, Carrie A. Grueter, Brad A. Grueter, Sachin Patel
Few therapies are currently available for patients with KRAS-driven cancers, highlighting the need to identify new molecular targets that modulate central downstream effector pathways. Here we found the miRNA cluster mir181ab1 as a key modulator of KRAS-driven oncogenesis. Ablation of Mir181ab1 in genetically-engineered mouse models of Kras-driven lung and pancreatic cancer was deleterious to tumor initiation and progression. Expression of both resident miRNAs in the Mir181ab1 cluster, miR181a1 and miR181b1, was necessary to rescue the Mir181ab1-loss phenotype underscoring their non-redundant role. In human cancer cells, depletion of miR181ab1 impaired proliferation and 3D growth, whereas overexpression provided a proliferative advantage. Lastly, we unveiled miR181ab1-regulated genes responsible for this phenotype. These studies identified what we believe to be a previously unknown role for miR181ab1 as a potential therapeutic target in two highly aggressive and difficult to treat KRAS-mutated cancers.
Karmele Valencia, Oihane Erice, Kaja Kostyrko, Simone Hausmann, Elizabeth Guruceaga, Anuradha Thathireddy, Natasha M. Flores, Leanne C. Sayles, Alex G. Lee, Rita Fragoso, Tian-Qiang Sun, Adrian Vallejo, Marta Roman, Rodrigo Entrialgo-Cadierno, Itziar Migueliz, Nerea Razquin, Puri Fortes, Fernando Lecanda, Jun Lu, Mariano Ponz-Sarvise, Chang-Zheng Chen, Pawel K. Mazur, E. Alejandro Sweet-Cordero, Silvestre Vicent
Genomics of primary prostate cancer differs from that of metastatic castration-resistant prostate cancer (mCRPC). We studied genomic aberrations in primary prostate cancer biopsies from patients who developed mCRPC, also studying matching, same patient, diagnostic and mCRPC biopsies following treatment. We profiled 470 treatment-naïve, prostate cancer diagnostic biopsies and for 61 cases, mCRPC biopsies using targeted and low-pass whole genome sequencing (n = 52). Descriptive statistics were used to summarize mutation and copy number profile. Prevalence was compared using Fisher's exact test. Survival correlations were studied using log-rank test. TP53 (27%) and PTEN (12%) and DDR gene defects (BRCA2 7%; CDK12 5%; ATM 4%) were commonly detected. TP53, BRCA2, and CDK12 mutations were significantly commoner than described in the TCGA cohort. Patients with RB1 loss in the primary tumour had a worse prognosis. Among 61 men with matched hormone-naïve and mCRPC biopsies, differences were identified in AR, TP53, RB1, and PI3K/AKT mutational status between same-patient samples. In conclusion, the genomics of diagnostic prostatic biopsies acquired from men who develop mCRPC differs to that of the primary prostatic cancers. RB1/TP53/AR aberrations are enriched in later stages, but the prevalence of DDR defects in diagnostic samples is similar to mCRPC.
Joaquin Mateo, George Seed, Claudia Bertan, Pasquale Rescigno, David Dolling, Ines Figueiredo, Susana Miranda, Daniel Nava Rodrigues, Bora Gurel, Matthew Clarke, Mark Atkin, Rob Chandler, Carlo Messina, Semini Sumanasuriya, Diletta Bianchini, Maialen Barrero, Antonella Petremolo, Zafeiris Zafeiriou, Mariane Sousa Fontes, Raquel Perez-Lopez, Nina Tunariu, Ben A. Fulton, Robert Jones, Ursula B. McGovern, Christy Ralph, Mohini Varughese, Omi Parikh, Suneil Jain, Tony Elliott, Shahneen Sandhu, Nuria Porta, Emma Hall, Wei Yuan, Suzanne Carreira, Johann S. de Bono
Recent findings have shown that inhibitors targeting BET (bromodomain and extraterminal domain) proteins, such as the small molecule JQ1, are potent growth inhibitors of many cancers and hold promise for cancer therapy. However, some reports also have revealed that JQ1 can activate additional oncogenic pathways and may affect EMT (epithelial mesenchymal transition). Therefore, it is important to address the potential unexpected effect of JQ1 treatment, such as cell invasion and metastasis. Here, we showed that in prostate cancer, JQ1 inhibited cancer cell growth but promoted invasion and metastasis in a BET protein independent manner. Multiple invasion pathways including EMT, BMP (bone morphogenetic protein) signaling, chemokine signaling and focal adhesion pathway were activated by JQ1 to promote invasion. Notably, JQ1 induced upregulation of invasion genes through inhibition of FOXA1, an invasion suppressor in prostate cancer. JQ1 directly interacted with FOXA1, inactivated FOXA1 binding to its interacting repressors, TLE3, HDAC7, and NFIC, thus blocking FOXA1 repressive function and activating the invasion genes. Our finding indicates that JQ1 has an unexpected effect of promoting invasion in prostate cancer. Thus, the ill effect of JQ1 or its derived therapeutic agents cannot be ignored during cancer treatment, especially in FOXA1 related cancers.
Leiming Wang, Mafei Xu, Chung-Yang Kao, Sophia Y. Tsai, Ming-Jer Tsai
The incidence of human papillomavirus (HPV)+ head and neck squamous cell carcinoma (HNSCC) has surpassed that of cervical cancer and is projected to increase rapidly until 2060. The co-evolution of HPV with transforming epithelial cells leads to the shutdown of host immune detection. Targeting proximal viral nucleic acid-sensing machinery is an evolutionarily conserved strategy among viruses to enable immune evasion. However, E7 from the dominant HPV subtype-16 in HNSCC shares low homology with HPV18 E7, which was shown to inhibit the STING-DNA-sensing pathway. The mechanisms by which HPV16 suppresses STING remain unknown. Recently, we characterized the role of the STING-type-I interferon (IFN-I) pathway in maintaining immunogenicity of HNSCC in mouse models. Here we extended those findings into clinical domain utilizing tissue microarrays and machine-learning-enhanced profiling of STING signatures with immune subsets. We additionally showed that HPV16 E7 employs distinct mechanisms than HPV18 E7 to antagonize the STING pathway. We identified NLRX1 as a critical intermediary partner to facilitate HPV16 E7-potentiated STING turnover. The depletion of NLRX1 resulted in significantly improved IFN-I-dependent T-cell infiltration profiles and tumor control. Overall, we discovered a unique HPV16 viral strategy to thwart host innate immune detection that can be further exploited to restore cancer immunogenicity.
Xiaobo Luo, Christopher R. Donnelly, Wang Gong, Blake R. Heath, Yuning Hao, Lorenza A. Donnelly, Toktam Moghbeli, Yee Sun Tan, Xin Lin, Emily Bellile, Benjamin A. Kansy, Thomas E. Carey, J. Chad Brenner, Lei Cheng, Peter J. Polverini, Meredith A. Morgan, Haitao Wen, Mark E. Prince, Robert L. Ferris, Yuying Xie, Simon Young, Gregory T. Wolf, Qianming Chen, Yu L. Lei
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