The lymph node stromal laminin alpha 5 shapes alloimmunity

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Abstract

Lymph node stromal cells (LNSC) regulate immunity through constructing lymphocyte niches. LNSC produced Laminin α5 (Lama5) regulates CD4 T cells but the underlying mechanisms of its functions are poorly understood. Here we showed depleting Lama5 in LNSC resulted in decreased Lama5 protein in the LN cortical ridge (CR) and around high endothelial venules (HEV). Lama5 depletion affected LN structure with increased HEV, upregulated chemokines and cell adhesion molecules, and led to greater numbers of Treg in T cell zone. Mouse and human T cell transendothelial migration and T cell entry to LN were suppressed by Lama5 through the receptors a6 integrin and α-dystroglycan. During immune responses and allograft transplantation, depleting Lama5 promoted antigen specific CD4 T cell entry to the CR through HEV, suppressed T cell activation and altered T cell differentiation to suppressive regulatory phenotypes. Enhanced allograft acceptance resulted from depleting Lama5 or blockade of T cell Lama5 receptors. Lama5 and Lama4:Lama5 ratios in allografts were associated with the rejection severity. Overall, our results demonstrated that stromal Lama5 regulated immune responses through altering LN structures and T cell behaviors. The study delineated a stromal Lama5-T cell receptors axis that can be targeted for immune tolerance modulation.

Authors

Lushen Li, Marina W. Shirkey, Tianshu Zhang, Yanbao Xiong, Wenji Piao, Vikas Saxena, Christina Paluskievicz, Young S. Lee, Nicholas Toney, Benjamin M. Cerel, Qinshan Li, Thomas Simon, Kyle D. Smith, Keli L. Hippen, Bruce R. Blazar, Reza Abdi, Jonathan S. Bromberg

Plasmacytoid dendritic cells sense HIV replication before detectable viremia following treatment interruption

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Abstract

Plasmacytoid dendritic cells (pDCs) are robust producers of interferon α (IFNα) and one of the first immune cells to respond to simian immunodeficiency virus infection. To elucidate responses to early HIV-1 replication, we studied blood pDCs in 29 HIV-infected participants who initiated antiretroviral therapy during acute infection and underwent analytic treatment interruption (ATI). An increased frequency of partially activated pDCs was observed in the blood prior to detection of HIV RNA. Concurrent with peak pDC frequency, there was a transient decline in the ability of pDCs to produce IFNα in vitro, which correlated with decreased interferon regulatory factory 7 (IRF7) and NF-kB phosphorylation. Levels of phosphorylated IRF7 and NF-kB inversely correlated with plasma IFNα2 levels, implying that pDCs were refractory to in vitro stimulation after IFNα production in vivo. After ATI, decreased expression of IFN genes in pDCs inversely correlated with time to viral detection, suggesting that pDC IFN loss is part of an effective early immune response. These data, from a limited cohort, provide a critical first step in understanding the earliest immune response to HIV-1 and suggest that changes in blood pDC frequency and function can be used as an indicator of viral replication before detectable plasma viremia.

Authors

Julie L. Mitchell, Hiroshi Takata, Roshell Muir, Donn J. Colby, Eugene Kroon, Trevor A. Crowell, Carlo Sacdalan, Suteeraporn Pinyakorn, Suwanna Pattamaswin, Khunthalee Benjapornpong, Rapee Trichavaroj, Randall L. Tressler, Lawrence Fox, Victoria R. Polonis, Diane L. Bolton, Frank Maldarelli, Sharon R. Lewin, Elias K. Haddad, Praphan Phanuphak, Merlin L. Robb, Nelson L. Michael, Mark de Souza, Nittaya Phanuphak, Jintanat Ananworanich, Lydie Trautmann

A tumor-intrinsic PD-L1-NLRP3 inflammasome signaling pathway drives resistance to anti-PD-1 immunotherapy

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Abstract

An in-depth understanding of immune escape mechanisms in cancer are likely to lead to innovative advances in immunotherapeutic strategies. However, much remains unknown regarding these mechanisms and how they impact immunotherapy resistance. Using several pre-clinical tumor models as well as clinical specimens, we report a newly identified mechanism whereby CD8+ T cell activation in response to PD-1 blockade induced a PD-L1-NLRP3 inflammasome signaling cascade that ultimately led to the recruitment of granulocytic myeloid-derived suppressor cells (PMN-MDSCs) into tumor tissues, thereby dampening the resulting anti-tumor immune response. The genetic and pharmacologic inhibition of NLRP3 suppressed PMN-MDSC tumor infiltration and significantly augmented the efficacy of anti-PD-1 antibody immunotherapy. This pathway therefore represents a tumor-intrinsic adaptive resistance mechanism to anti-PD-1 checkpoint inhibitor immunotherapy and is a promising target for future translational research.

Authors

Balamayooran Theivanthiran, Kathy S. Evans, Nicholas C. DeVito, Michael P. Plebanek, Michael Sturdivant, Lucas P. Wachsmuth, April K.S. Salama, Yubin Kang, David Hsu, Justin M. Balko, Douglas B. Johnson, Mark Starr, Andrew B. Nixon, Alisha Holtzhausen, Brent A. Hanks

Targetable ERBB2 mutations identified in neurofibroma/schwannoma hybrid nerve sheath tumors

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Abstract

Background: Neurofibroma/schwannoma hybrid nerve sheath tumors (N/S HNSTs) are neoplasms associated with larger nerves that occur sporadically and in the context of schwannomatosis or neurofibromatosis type 2 or 1. Clinical management of N/S HNST is challenging, especially for large tumors, and established systemic treatments are lacking. Methods: We used next-generation sequencing and array-based DNA methylation profiling to determine the clinically actionable genomic and epigenomic landscapes of N/S HNST. Results: Whole-exome sequencing within a precision oncology program identified an activating mutation (p.Asp769Tyr) in the catalytic domain of the ERBB2 receptor tyrosine kinase in a patient with schwannomatosis-associated N/S HNST, and targeted treatment with the small-molecule ERBB inhibitor lapatinib led to prolonged clinical benefit and a lasting radiographic and metabolic response. Analysis of a multicenter validation cohort revealed recurrent ERBB2 mutations (p.Leu755Ser, p.Asp769Tyr, p.Val777Leu) in N/S HNSTs occurring in patients who met diagnostic criteria for sporadic schwannomatosis (3 of 7 patients), but not in N/S HNSTs arising in the context of neurofibromatosis (6 patients) or outside a tumor syndrome (1 patient), and showed that ERBB2-mutant N/S HNSTs cluster in a distinct subgroup of peripheral nerve sheath tumors based on genome-wide DNA methylation patterns. Conclusion: These findings uncover a key biological feature of N/S HNST that may have important diagnostic and therapeutic implications. Funding: This work was supported by grant H021 from DKFZ-HIPO. MWR and PNH have received fellowships from UCT Frankfurt, and MWR has received funding from the Frankfurt Research Funding Clinician Scientist Program.

Authors

Michael W. Ronellenfitsch, Patrick N. Harter, Martina Kirchner, Christoph Heining, Barbara Hutter, Laura Gieldon, Jens Schittenhelm, Martin U. Schuhmann, Marcos Tatagiba, Gerhard Marquardt, Marlies Wagner, Volker Endris, Christian H. Brandts, Victor-Felix Mautner, Evelin Schröck, Wilko Weichert, Benedikt Brors, Andreas von Deimling, Michel Mittelbronn, Joachim P. Steinbach, David E. Reuss, Hanno Glimm, Albrecht Stenzinger, Stefan Fröhling

Molecular cross-talk between Y5-receptor and neuropeptide Y drives liver cancer

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Abstract

Hepatocellular carcinoma (HCC) is clearly age-related and represents one of the deadliest cancer types worldwide. Due to globally increasing risk factors including metabolic disorders, the incidence rates of HCC are still rising. However, the molecular hallmarks of HCC remain poorly understood. Neuropeptide Y (NPY) and NPY-receptors represent a highly conserved, stress-activated system which is involved in diverse cancer-related hallmarks including aging and metabolic alterations, but its impact on liver cancer had been unclear. Here, we observed increased NPY5-receptor (Y5R) expression in HCC which correlated with tumor growth and survival. Furthermore, we found that its ligand NPY was secreted by peri-tumorous hepatocytes. Hepatocyte-derived NPY promoted HCC progression by Y5R-activation. Transforming growth factor beta 1 (TGFβ1) was identified as a regulator of NPY in hepatocytes and induced Y5R in invasive cancer cells. Moreover, NPY-conversion by dipeptidylpeptidase 4 (DPP4) augmented Y5R-activation and function in liver cancer. The TGFβ-NPY-Y5R-axis and DPP4 represent attractive therapeutic targets for controlling liver cancer progression.

Authors

Peter Dietrich, Laura Wormser, Valerie Fritz, Tatjana Seitz, Monica De Maria, Alexandra Schambony, Andreas E. Kremer, Claudia Günther, Timo Itzel, Wolfgang E. Thasler, Andreas Teufel, Jonel Trebicka, Arndt Hartmann, Markus F. Neurath, Stephan von Hörsten, Anja Bosserhoff, Claus Hellerbrand

GPR160 de-orphanization reveals critical roles in neuropathic pain in rodents

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Abstract

Treating neuropathic pain is challenging and novel non-opioid based medicines are needed. Using unbiased receptomics, transcriptomic analyses, immunofluorescence and in situ hybridization, we found the expression of the orphan GPCR (oGPCR) Gpr160 and GPR160 increased in the rodent dorsal horn of the spinal cord (DH-SC) following traumatic nerve injury. Genetic and immunopharmacological approaches demonstrated that GPR160 inhibition in the spinal cord prevented and reversed neuropathic pain in male and female rodents without altering normal pain response. GPR160 inhibition in the spinal cord attenuated sensory processing in the thalamus, a key relay in the sensory discriminative pathways of pain. We also identified cocaine- and amphetamine-regulated transcript peptide (CARTp) as a GPR160 ligand. Inhibiting endogenous CARTp signaling in spinal cord attenuated neuropathic pain, whereas exogenous intrathecal (i.th.) CARTp evoked painful hypersensitivity through GPR160-dependent ERK and cAMP response element-binding protein (CREB). Our findings de-orphanize GPR160, identify it as a determinant of neuropathic pain and potential therapeutic target, and provide insights to its signaling pathways. CARTp is involved in many diseases including depression, reward and addiction, de-orphanization of GPR160 is a major step forward understanding the role of CARTp signaling in health and disease.

Authors

Gina LC Yosten, Caron M. Harada, Christopher J. Haddock, Luigino Antonio Giancotti, Grant R. Kolar, Ryan Patel, Chun Guo, Zhoumou Chen, Jinsong Zhang, Timothy M. Doyle, Anthony H. Dickenson, Willis K. Samson, Daniela Salvemini

Dysfunctional polycomb transcriptional repression contributes to Lamin A/C dependent muscular dystrophy

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Abstract

Lamin A is a component of the inner nuclear membrane that, together with epigenetic factors, organizes the genome in higher order structures required for transcriptional control. Mutations in the Lamin A/C gene cause several diseases, belonging to the class of laminopathies, including muscular dystrophies. Nevertheless, molecular mechanisms involved in the pathogenesis of Lamin A-dependent dystrophies are still largely unknown. Polycomb group of proteins (PcG) are epigenetic repressors and Lamin A interactors, primarily involved in the maintenance of cell identity. Using a murine model of Emery-Dreifuss Muscular Dystrophy (EDMD), we showed here that Lamin A loss deregulated PcG positioning in muscle satellite stem cells leading to de-repression of non-muscle specific genes and p16INK4a, a senescence driver encoded in the Cdkn2a locus. This aberrant transcriptional programme caused impairment in self-renewal, loss of cell identity and premature exhaustion of quiescent satellite cell pool. Genetic ablation of Cdkn2a locus restored muscle stem cell properties in Lamin A/C null dystrophic mice. Our findings established a direct link between Lamin A and PcG epigenetic silencing and indicated that Lamin A-dependent muscular dystrophy can be ascribed to intrinsic epigenetic dysfunctions of muscle stem cells.

Authors

Andrea Bianchi, Chiara Mozzetta, Gloria Pegoli, Federica Lucini, Sara Valsoni, Valentina Rosti, Cristiano Petrini, Alice Cortesi, Francesco Gregoretti, Laura Antonelli, Gennaro Oliva, Marco De Bardi, Roberto Rizzi, Beatrice Bodega, Diego Pasini, Francesco Ferrari, Claudia Bearzi, Chiara Lanzuolo

TRPV4 channel opening mediates pressure-induced pancreatitis initiated by Piezo1 activation

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Abstract

Elevated pressure in the pancreatic gland is the central cause of pancreatitis following abdominal trauma, surgery, endoscopic retrograde cholangiopancreatography (ERCP), and gallstones. In the pancreas excessive intracellular calcium causes mitochondrial dysfunction, premature zymogen activation, and necrosis ultimately leading to pancreatitis. Although stimulation of the mechanically activated, calcium-permeable ion channel, Piezo1, in the pancreatic acinar cell is the initial step in pressure-induced pancreatitis, activation of Piezo1 produces only transient elevation in intracellular calcium that is insufficient to cause pancreatitis. Therefore, how pressure produces a prolonged calcium elevation necessary to induce pancreatitis is unknown. We demonstrate that Piezo1 activation in pancreatic acinar cells caused a prolonged elevation in intracellular calcium levels, mitochondrial depolarization, intracellular trypsin activation, and cell death. Notably, these effects were dependent on the degree and duration of force applied to the cell. Low or transient force were insufficient to activate these pathological changes whereas higher and prolonged application of force triggered sustained elevation in intracellular calcium leading to enzyme activation and cell death. All of these pathological events were rescued in acinar cells treated with a Piezo1 antagonist and in acinar cells from mice with genetic deletion of Piezo1. We discovered that Piezo1 stimulation triggered TRPV4 channel opening which was responsible for the sustained elevation in intracellular calcium that caused intracellular organelle dysfunction. Moreover, TRPV4 gene knockout mice were protected from Piezo1 agonist- and pressure-induced pancreatitis. These studies unveil a calcium signaling pathway in which Piezo1-induced TRPV4 channel opening causes pancreatitis.

Authors

Sandip M. Swain, Joelle M.J. Romac, Rafiq A. Shahid, Stephen J. Pandol, Wolfgang Liedtke, Steven R. Vigna, Rodger A. Liddle

Marked and rapid effects of pharmacological HIF-2α antagonism on hypoxic ventilatory control

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Abstract

Hypoxia-inducible factor (HIF) is strikingly upregulated in many types of cancer and there is great interest in applying inhibitors of HIF as anti-cancer therapeutics. The most advanced of these are small molecules that target the HIF-2 isoform through binding the PAS-B domain of HIF-2α. These molecules are undergoing clinical trials with promising results in renal and other cancers where HIF-2 is considered to be driving growth. Nevertheless, a central question remains as to whether such inhibitors impact on physiological responses to hypoxia at relevant doses. Here we show that pharmacological HIF-2α inhibition with PT2385, at doses similar to those reported to inhibit tumour growth, rapidly impaired ventilatory responses to hypoxia, abrogating both ventilatory acclimatisation and carotid body cell proliferative responses to sustained hypoxia. Mice carrying a HIF-2α PAS-B S305M mutation that disrupts PT2385 binding, but not dimerisation with HIF-1β, did not respond to PT2385 indicating that these effects are on target. Furthermore, the finding of a hypomorphic ventilatory phenotype in untreated HIF-2α S305M mutant mice suggests a function for the HIF-2α PAS-B domain beyond heterodimerisation with HIF-1β. Although PT2385 was well-tolerated, the findings indicate the need for caution in patients who are dependent on hypoxic ventilatory drive.

Authors

Xiaotong Cheng, Maria Prange-Barczynska, James W. Fielding, Minghao Zhang, Alana L. Burrell, Joanna D.C.C. Lima, Luise Eckardt, Isobel L.A. Argles, Christopher W. Pugh, Keith J. Buckler, Peter A. Robbins, Emma J. Hodson, Richard K. Bruick, Lucy M. Collinson, Fraydoon Rastinejad, Tammie Bishop, Peter J. Ratcliffe

TGFβ-induced epigenetic deregulation of SOCS3 facilitates STAT3-signaling to promote fibrosis

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Abstract

Fibroblasts are key-effector cells in tissue remodeling. They remain persistently activated in fibrotic diseases, resulting in progressive deposition of extracellular matrix. Although fibroblast activation maybe initiated by external factors, prolonged activation can induce an “autonomous”, self-maintaining pro-fibrotic phenotype in fibroblasts. Accumulating evidence suggests that epigenetic alterations play a central role to establish this persistently activated pathologic phenotype of fibroblasts. We demonstrated that in fibrotic skin of patients with systemic sclerosis (SSc), a prototypical idiopathic fibrotic disease, transforming growth factor-β (TGFβ) induced the expression of DNA-methyltransferase 3A (DNMT3A) and DNMT1 in fibroblasts in a SMAD-dependent manner to silence the expression of suppressor of cytokine signaling 3 (SOCS3) by promoter hypermethylation. Downregulation of SOCS3 facilitated activation of signal transducers and activators of transcription 3 (STAT3) to promote fibroblast-to–myofibroblast transition, collagen release and fibrosis in vitro and in vivo. Re-establishment of the epigenetic control of STAT3 signaling by genetic or pharmacological inactivation of DNMT3A reversed the activated phenotype of SSc fibroblasts in tissue culture, inhibited TGFβ-dependent fibroblast activation and ameliorated experimental fibrosis in murine models. These findings identify a novel pathway of epigenetic imprinting of fibroblasts in fibrotic disease with translational implications for the development of new targeted therapies in fibrotic diseases.

Authors

Clara Dees, Sebastian Pötter, Yun Zhang, Christina Bergmann, Xiang Zhou, Markus Luber, Thomas Wohlfahrt, Emmanuel Karouzakis, Andreas Ramming, Kolja Gelse, Akihiko Yoshimura, Rudolf Jaenisch, Oliver Distler, Georg Schett, Jörg H.W. Distler