Research
Abstract
Loss-of-function (LOF) variants in IL6ST, encoding GP130, can cause hyper-IgE syndrome (HIES). Monoallelic LOF variants in IL6ST lead to HIES when located in the intracellular domain downstream of box 1/2 and upstream of the STAT3 phosphorylation sites and the recycling motif, due to their dominant negative (DN) activity. In this region, two previously unreported IL6ST variants, p.K702Sfs7* and p.Y759Wfs26*, were identified in two families with autosomal dominant (AD) HIES. Both variants were LOF, exhibited DN effects, leading to the accumulation of mutant GP130 on the cell surface. The p.K702Sfs7* mutation was the most upstream N-terminal mutation linked to HIES caused by heterozygous IL6ST variants. Comprehensive screening of IL6ST mutants revealed that most premature terminations downstream of amino acid F641, at the end of the transmembrane domain, resulted in LOF and DN effects via GP130 accumulation on the cell surface. The absence of the recycling motif (positions 782-787) in surface-expressed LOF GP130 led to its accumulation, contributing to the DN effect. The importance of intracellular truncating IL6ST variants can possibly be predicted based on the location of the premature stop codon. GP130 accumulation on the cell surface is a characteristic and potentially diagnostic finding in HIES patients with heterozygous IL6ST variants.
Authors
Kosuke Ashihara, Takaki Asano, Kanako Takeuchi, Kosuke Noma, Miyuki Tsumura, Wenjie Wang, Wei-Te Lei, Hisao Higo, Toshio Kubo, Yoko Mizoguchi, Shuhei Karakawa, Aurélie Cobat, Clément Conil, Etsushi Toyofuku, Akimasa Sekine, Kohsuke Imai, Dusan Bogunovic, Jean-Laurent Casanova, Cheng-Lung Ku, Vivien Béziat, Satoshi Okada
Abstract
Hypoxia-inducible factors (HIFs) promote lung protection and pathogen eradication during acute lung injury. We therefore tested the theory that pharmacologic stabilization of HIFs dampens lung injury during SARS-CoV-2 pneumonia. Initial studies in murine SARS-CoV-2 models showed improved outcomes after treatment with the FDA-approved HIF-stabilizer vadadustat. Subsequent studies in genetic models implicated alveolar-expressed Hif1a in mediating lung protection. Therefore, we performed a randomized, double-blinded, multicenter phase 2 trial in patients admitted for SARS-CoV-2 infection and concomitant hypoxia (SpO2 ≤ 94%). Patients (n=448) were randomized to oral vadadustat (900 mg/day) or placebo for up to 14 days. Safety events were similar between the two groups. Vadadustat treatment induced surrogate HIF-target genes. The primary outcome of severe lung injury requiring high oxygen support on day 14 occurred in 43 patients in the vadadustat group and 53 patients in the placebo group (estimated probability, 13.3% vs. 16.9%). Among patients with baseline FiO2 ≥ 80% (n=106), the estimated probability of the primary outcome was 12.1% (vadadustat) vs. 79.1% (placebo), indicating an even greater benefit in patients with more severe baseline hypoxia. HIF1A is a likely therapeutic target during SARS-CoV-2-associated lung injury. Robust clinical trials of HIF stabilizers during pathogen-associated lung injury are warranted.
Authors
Bentley Bobrow, Samuel D. Luber, Paul Potnuru, Katherine Figarella, Jieun Kim, Yanyu Wang, In Hyuk Bang, David Robinson, Paulina B. Sergot, Steven K. Burke, Tingting Mills, Constanza de Dios, Robert Suchting, George W. Williams, Adit A. Ginde, Yafen Liang, Hongfang Liu, Charles Green, Marie-Francoise Doursout, Alparslan Turan, Daniel I. Sessler, Xiaoyi Yuan, Holger K. Eltzschig
Abstract
Although obesity is a major risk factor for cancer, it may also improve the response to cancer therapy. Here we investigated the impact of obesity on the efficacy of immune checkpoint inhibitors (ICI). In male mice, obesity promoted tumor growth but enhanced the response to ICI. This was associated with higher expression of immune-related genes within the tumor and enhanced infiltration of tumor-specific CD8+ T cells. Further, obesity in mice was associated with higher estrogen levels and enrichment of estrogen response genes in the tumor, and anti-PD-1 efficacy was reduced upon administration of the aromatase inhibitor letrozole, which blocks the production of estrogens. Mechanistically, adipocyte-derived estrogens increased antigen presentation by dendritic cells and tumor-specific CD8+ T-cell cytotoxicity. Lastly, overweight and obese male melanoma patients responded better to ICI, high estrogen levels being associated with improved response and survival. Our results suggest that estrogens may serve as a predictive factor of response to ICI in men with melanoma.
Authors
Eloïse Dupuychaffray, Hélène Poinot, Aurélie Vuilleumier, Maxime Borgeaud, Montserrat Alvarez, Betül Taskoparan, Olivier Preynat-Seauve, Clarissa D. Voegel, Eliana Marinari, Denis Migliorini, Valérie Dutoit, Carole Bourquin, Aurélien Pommier
Abstract
More than one in four men will undergo surgery for inguinal hernia, which is commonly associated with fibrotic degeneration of the lower abdominal muscle (LAM) in the groin region. Utilizing a male mouse model expressing the human aromatase gene (Aromhum), previous studies showed that locally produced estradiol acting via estrogen receptor alpha in LAM fibroblasts leads to fibrosis, myofiber atrophy, and hernia development. Here, we found that upregulation of progesterone receptor (PGR) in a LAM fibroblast population mediates this estrogenic effect. A PGR-selective progesterone antagonist in Aromhum mice decreased LAM fibrosis and atrophy, preventing hernia formation and stopping progression of existing hernias. Addition of progesterone to estradiol treatment was essential for early-onset development of LAM fibrosis and large hernias in wild type mice, which was averted by a progesterone antagonist. Single-nuclei multiomics sequencing of herniated LAM revealed a unique population of Pgr-expressing fibroblasts that promotes fibrosis and myofiber atrophy through transforming growth factor beta-2 signaling. Multiomics findings were validated in vivo in herniated LAM tissues of both mice and adult men. Our findings suggest an important and rare pathologic role of progesterone signaling in males and provide evidence for progesterone antagonists as a non-surgical alternative for inguinal hernia management.
Authors
Tianming You, Mehrdad Zandigohar, Tanvi Potluri, Natalie Piehl, John S. Coon V, Elizabeth Baker, Maya Kafali, Yang Dai, Jonah J. Stulberg, David J. Escobar, Richard L. Lieber, Hong Zhao, Serdar E. Bulun
Csk-mediated Src family kinase regulation dampens neutrophil infiltration during pulmonary infection
Abstract
Neutrophil recruitment is crucial for pathogen elimination. However, precise control of the inflammatory response prevents overshooting reactions. Neutrophil activation initiates signaling resulting in integrin beta 2 (Itgb2) activation and neutrophil arrest. Src family kinases are involved in multiple cellular processes and are negatively regulated by the C-terminal Src kinase (Csk). During this study, we investigated the mechanism by which Csk regulates integrin activation and neutrophil recruitment. Here, we demonstrated that Csk deficiency in murine neutrophils resulted in increased neutrophil adhesion to the endothelium along with decreased neutrophil transmigration into inflamed tissues compared to their littermate controls. In bacterial pneumonia, infected Csk-deficient mice showed higher bacterial burdens and decreased neutrophil recruitment, while other immune cell counts and cytokine levels were not significantly different compared to control. Analyses of Csk-deficient neutrophils revealed an increased Itgb2 affinity, leading to reduced migration and intravascular crawling. Mechanistically, elevated cAMP-levels increased protein kinase A activity, which subsequently enhanced Csk activation. Csk, in turn, suppressed Src family kinases activation through phosphorylation (Y529). Hence, Csk-mediated regulation of neutrophil infiltration contributes to maintain a balanced immune response during bacterial pneumonia.
Authors
Wida Amini, Lena Schemmelmann, Jan-Niklas Heming, Marina Oguama, Katharina Thomas, Helena Block, Pia Lindental, Bernadette Bardel, Andreas Margraf, Oliver Soehnlein, Anika Cappenberg, Alexander Zarbock
Abstract
Multiple sclerosis is characterized by CNS infiltration of auto-reactive immune cells that drive both acute inflammatory demyelination and chronic progressive axonal and neuronal injury. Expanding evidence implicates CD8+ anti-neural T cells in the irreversible neurodegeneration that underlies progression in multiple sclerosis, yet therapies specifically targeting this cell population are limited. CD8+ T cells from patients with MS exhibit increased engagement of the pentose phosphate pathway. Pharmacologic inhibition of the pentose phosphate pathway reduced glycolysis, glucose uptake, NADPH production, ATP production, proliferation, and proinflammatory cytokine secretion in CD8+ T cells activated by ligation of CD3 and CD28. Pentose phosphate pathway inhibition also prevented CD8+ T cell-mediated antigen-specific neuronal injury in vitro and in both an adoptive transfer-based cuprizone model of demyelination and in mice with experimental autoimmune encephalomyelitis. Notably, transcriptional profiling of CNS-infiltrating CD8+ T cells in patients with MS indicated increased pentose phosphate pathway engagement, suggesting that this pathway is involved in CD8+ T cell-mediated injury of axons and neurons in the demyelinated CNS. Inhibiting the pentose phosphate pathway disrupts CD8+ T cell metabolic reprogramming and effector functions, suggesting that such inhibition may serve as a therapeutic strategy to prevent neurodegeneration in patients with progressive MS.
Authors
Ethan M. Grund, Benjamin D.S. Clarkson, Susanna Pucci, Maria S. Westphal, Carolina Muniz Partida, Sara A. Muhammad, Charles L. Howe
Abstract
The prognosis for colorectal cancer (CRC) patients with liver metastasis remains poor, and the molecular mechanisms driving CRC liver metastasis are still not fully understood. Hypoxia-induced extracellular vesicles (H-EVs) derived from tumors have emerged as key players in inducing angiogenesis by transferring non-coding RNAs. However, the specific role of CRC-derived hypoxic EVs (H-EVs) in regulating the formation of the pre-metastatic microenvironment (PMN) by inducing angiogenesis remains unclear. Our study demonstrates that H-EVs induce both angiogenesis and liver metastasis. Through microRNA microarray analysis, we identified a reduction in miR-6084 levels within H-EVs. We found that miR-6084 inhibits angiogenesis by being transferred to endothelial cells via EVs. In endothelial cells, miR-6084 directly targets ANGPTL4 mRNA, thereby suppressing angiogenesis through ANGPTL4-mediated JAK2/STAT3 pathway. Furthermore, we uncovered that SP1 acts as a transcription factor regulating miR-6084 transcription, while HIF1A decreases miR-6084 expression by promoting SP1 protein dephosphorylation and facilitating ubiquitin‒proteasome degradation in SW620 cells. In clinical samples, we observed low expression of miR-6084 in plasma-derived EVs from CRC patients with liver metastasis. In summary, our findings suggest that CRC-derived hypoxic EVs promote angiogenesis and liver metastasis through the HIF1A/SP1/miR-6084/ANGPTL4 axis. Additionally, miR-6084 holds promise as a potential diagnostic and prognostic biomarker for CRC liver metastasis.
Authors
Yang Zhang, Xuyang Yang, Su Zhang, Qing Huang, Sicheng Liu, Lei Qiu, Mingtian Wei, Xiangbing Deng, Wenjian Meng, Hai-Ning Chen, Yaguang Zhang, Junhong Han, Ziqiang Wang
Abstract
For over a century, scientists reported the disruption of normal nuclear shape and size in cancer. These changes have long been used as tools for diagnosis and staging of malignancies. However, to date, the mechanisms underlying these aberrant nuclear phenotypes and their biological significance remain poorly understood. Using a model of pancreatic ductal adenocarcinoma (PDAC), the major histological subtypes of pancreatic cancer, we found oncogenic mutant KRAS reduces nuclear size. Transcriptomic and protein expression analysis of mutant KRAS-expressing PDAC cells revealed differential levels of several nuclear envelope-associated genes. Further analysis demonstrated the nuclear lamina protein, Emerin (EMD), acted downstream of KRAS to mediate nuclear size reduction in PDAC. Analysis of human PDAC samples showed that increased EMD expression associates with reduced nuclear size. Finally, in vivo genetic depletion of EMD in a mutant KRAS-driven PDAC model resulted in an increased nuclear size and a reduced incidence of poorly differentiated PDAC. Thus, our data provides evidence of a novel mechanism underlying nuclear size regulation and its impact in PDAC carcinogenesis.
Authors
Luis F. Flores, David L. Marks, Renzo E. Vera, Ashley N. Sigafoos, Ezequiel J. Tolosa, Luciana L. Almada, David R. Pease, Merih D. Toruner, Brian Chang, Brooke R. Tader, Kayla C. LaRue-Nolan, Ryan M. Carr, Rondell P. Graham, Catherine E. Hagen, Matthew R. Brown, Aleksey V. Matveyenko, Katherine L. Wilson, David W. Dawson, Christopher L. Pin, Kyle J. Roux, Martin E. Fernandez-Zapico
Abstract
Podocytes are kidney glomerular cells that depend on rigorously regulated cytoskeleton components and integrins to form and maintain the so-called foot processes, apparatuses that attach podocytes to the glomerular basement membrane and connect them to neighboring podocytes. In diabetic kidney disease (DKD) these foot processes are effaced as a result of cytoskeleton dysregulation, a phenomenon that gradually reduces glomerular filtration. Cytoskeleton-associated protein 4 (CKAP4) is a known linker between the endoplasmic reticulum, integrins and microtubular cytoskeleton. Since CKAP4 gene expression is downregulated in glomeruli from DKD patients but not in other chronic kidney diseases, we hypothesized a role for CKAP4 in the mechanisms leading to foot process effacement (FPE) in DKD. CKAP4 mRNA reduction in podocytes in DKD was demonstrated in human kidney biopsies. Knockdown of CKAP4 in vivo in zebrafish resulted in edema, proteinuria and foot process effacement, all typical features of DKD. Knockdown of CKAP4 in vitro led to disruption of the actin cytoskeleton and of the microtubular orientation. Moreover, it caused a downregulation of several integrins. These findings indicate that CKAP4 is crucial for foot process dynamics of podocytes. Its reduction, unique to DKD, is mechanistically connected to the pathophysiological processes leading to podocyte FPE.
Authors
Roberto Boi, Emelie Lassén, Alva Johansson, Peidi Liu, Aditi Chaudhari, Ramesh Tati, Janina Müller-Deile, Mario Schiffer, Kerstin Ebefors, Jenny Nyström
Abstract
Kidney thick ascending limb cells reabsorb sodium, potassium, calcium, magnesium and contribute to urinary concentration. These cells are typically viewed as a single type that recycles potassium across the apical membrane and generates a lumen-positive transepithelial voltage driving calcium and magnesium reabsorption, although variability in potassium channel expression has been reported. Additionally, recent transcriptomic analyses suggest that different cell types exist along this segment, but classifications have varied and have not led to a new consensus model. We used immunolocalization, electrophysiology and enriched single nucleus RNA-Seq to identify thick ascending limb cell types in rat, mouse and human. We identified three major TAL cell types defined by expression of potassium channels and claudins. One has apical potassium channels, low basolateral potassium conductance, and is bordered by a monovalent cation-permeable claudin. A second lacks apical potassium channels, has high basolateral potassium conductance and is bordered by calcium- and magnesium-permeable claudins. A third type also lacks apical potassium channels and has high basolateral potassium conductance, but these cells are ringed by monovalent cation-permeable claudins. The recognition of diverse cell types may resolve longstanding questions about how solute transport can be modulated selectively and how disruption of these cells leads to human disease.
Authors
Hasan Demirci, Jessica P. Bahena-Lopez, Alina Smorodchenko, Xiao-Tong Su, Jonathan W. Nelson, Chao-Ling Yang, Joshua N. Curry, Xin-Peng Duan, Wen-Hui Wang, Yuliya Sharkovska, Ruisheng Liu, Duygu Elif Yilmaz, Catarina Quintanova, Katie Emberley, Ben Emery, Nina Himmerkus, Markus Bleich, David H. Ellison, Sebastian Bachmann
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