Li et al. report that KLF15 is required for maintenance of white adipocyte properties in subcutaneous fat depots and is a potential therapeutic target for obesity and associated diseases. The cover image shows multilocular beige adipocytes in a subcutaneous depot of a Klf15-deficient mouse. Image credit: Liang Li.
Cytomegalovirus (CMV) is one of the most common and relevant opportunistic pathogens in immunocompromised individuals such as kidney transplant recipients (KTRs). The exact mechanisms underlying the disability of cytotoxic T cells to provide sufficient protection against CMV in immunosuppressed individuals have not been identified yet. Here, we performed in-depth metabolic profiling of CMV-specific CD8+ T cells in immunocompromised patients and show the development of metabolic dysregulation at the transcriptional, protein, and functional level of CMV-specific CD8+ T cells in KTRs with non-controlled CMV infection. These dysregulations comprise impaired glycolysis and increased mitochondrial stress, which is associated with an intensified expression of the nicotinamide adenine dinucleotide nucleotidase (NADase) CD38. Inhibiting NADase activity of CD38 reinvigorated the metabolism and improved cytokine production of CMV-specific CD8+ T cells. These findings were corroborated in a mouse model of CMV infection under conditions of immunosuppression. Thus, dysregulated metabolic states of CD8+ T cells could be targeted by inhibiting CD38 to reverse hypo-responsiveness in individuals who fail to control chronic viral infection.
Nils Mülling, Felix M. Behr, Graham A. Heieis, Kristina Boss, Suzanne van Duikeren, Floortje J. van Haften, Iris N. Pardieck, Esmé T.I. van der Gracht, Ward Vleeshouwers, Tetje C. van der Sluis, J. Fréderique de Graaf, Dominique M.B. Veerkamp, Kees L.M.C. Franken, Xin Lei, Lukas van de Sand, Sjoerd H. van der Burg, Marij J.P. Welters, Sebastiaan Heidt, Wesley Huisman, Simon P. Jochems, Martin Giera, Oliver Witzke, Aiko P.J. de Vries, Andreas Kribben, Bart Everts, Benjamin Wilde, Ramon Arens
Cystic fibrosis (CF) results from mutations in the CFTR anion channel, ultimately leading to diminished transepithelial anion secretion and mucociliary clearance. CFTR correctors are therapeutics that restore the folding/trafficking of mutated CFTR to the plasma membrane. The BKCa potassium channel is also critical for maintaining lung ASL volume. Here, we show the CFTR corrector, VX-445 (Elexacaftor), a component of Trikafta, induces K+ secretion across WT and F508del CFTR primary human bronchial epithelial cells (HBEs), which was entirely inhibited by the BKCa antagonist paxilline. Similar results were observed with VX-121 – a corrector under clinical evaluation. Whole-cell patch-clamp recordings confirmed potentiated channel activity from CFTR correctors on the BKCa α-subunit, and excised patch-clamp recordings demonstrated a significant increase in open probability. In mesenteric artery, VX-445 induced a paxilline-sensitive vasorelaxation of preconstricted arteries. VX-445 also reduced action potential firing frequency in primary hippocampal and cortical neurons. VX-445 effects were observed at low micomolar concentrations (1-10 µM) – within the range reported in plasma and tissues from CF patients. We raise the possibilities that CFTR correctors gain additional clinical benefit by activation of BKCa in the lung, yet may lead to adverse events through BKCa activation, elsewhere.
Aaron Kolski-Andreaco, Stefanie Taiclet, Michael M. Myerburg, john sembrat, Robert J. Bridges, Adam C. Straub, Zachary P. Wills, Michael B. Butterworth, Daniel C. Devor
The progression of kidney disease varies among individuals, but a general methodology to quantify disease timelines is lacking. Particularly challenging is the task of determining the potential for recovery from acute kidney injury following various insults. Here, we report that quantitation of post-transcriptional adenosine-to-inosine (A-to-I) RNA editing offers a distinct genome-wide signature, enabling the delineation of disease trajectories in the kidney. A well-defined murine model of endotoxemia permitted the identification of the origin and extent of A-to-I editing, along with temporally discrete signatures of double-stranded RNA stress and Adenosine Deaminase isoform switching. We found that A-to-I editing of Antizyme Inhibitor 1 (AZIN1), a positive regulator of polyamine biosynthesis, serves as a particularly useful temporal landmark during endotoxemia. Our data indicate that AZIN1 A-to-I editing, triggered by preceding inflammation, primes the kidney and activates endogenous recovery mechanisms. By comparing genetically modified human cell lines and mice locked in either A-to-I edited or uneditable states, we uncovered that AZIN1 A-to-I editing not only enhances polyamine biosynthesis but also engages glycolysis and nicotinamide biosynthesis to drive the recovery phenotype. Our findings implicate that quantifying AZIN1 A-to-I editing could potentially identify individuals who have transitioned to an endogenous recovery phase. This phase would reflect their past inflammation and indicate their potential for future recovery.
Segewkal Hawaze Heruye, Jered Myslinski, Chao Zeng, Amy Zollman, Shinichi Makino, Azuma Nanamatsu, Quoseena Mir, Sarath Chandra Janga, Emma H. Doud, Michael T. Eadon, Bernhard Maier, Michiaki Hamada, Tuan M. Tran, Pierre C. Dagher, Takashi Hato
Aortic aneurysm is a life-threatening disease with limited interventions, closely related to vascular smooth muscle cells (VSMCs) phenotypic switching. SLC44A2, a member of solute carrier series 44 (SLC44) family, remains under-characterized in the context of cardiovascular diseases. Venn diagram analysis based on microarray and single-cell RNA sequencing identified SLC44A2 as a major regulator of VSMCs phenotypic switching in aortic aneurysm. Screening for Slc44a2 amongst aortic cell lineages demonstrated its predominant location in VSMCs. Elevated levels of SLC44A2 were evidenced in the aorta of both abdominal aortic aneurysm patients and angiotensin II (Ang II)-infused Apoe–/– mice. In vitro, SLC44A2 silencing promoted VSMCs towards a synthetic phenotype, while SLC44A2 overexpression attenuated VSMCs phenotypic switching. VSMCs-specific SLC44A2 knockout mice were more susceptible to aortic aneurysm under Ang II infusion, while SLC44A2 overexpression showed protective effects. Mechanistically, SLC44A2 interaction with NRP1 and ITGB3 activates TGF-β/SMAD signaling, thereby promoting contractile genes expression. Elevated SLC44A2 in aortic aneurysm is associated with upregulated runt-related transcription factor 1 (RUNX1). Furthermore, low dose of lenalidomide (LEN) suppressed aortic aneurysm progression by enhancing SLC44A2 expression. These findings reveal SLC44A2/NRP1/ITGB3 complex is a major regulator of VSMCs phenotypic switching and provide potential therapeutic approach (LEN) for aortic aneurysm treatment.
Tianyu Song, Shuang Zhao, Shanshan Luo, Chuansheng Chen, Xingeng Liu, Xiaoqi Wu, Zhongxu Sun, Jiawei Cao, Ziyu Wang, Yineng Wang, Bo Yu, Zhiren Zhang, Xiaolong Du, Xiaoqiang Li, Zhijian Han, Hongshan Chen, Feng Chen, Liansheng Wang, Hong Wang, Kangyun Sun, Yi Han, Liping Xie, Yong Ji
Leukemia relapse is a major cause of death after allogeneic hematopoietic cell transplantation (allo-HCT). We tested the potential of targeting TIM-3 for improving graft-versus-leukemia (GVL) effects. We observed differential expression of TIM-3 ligands when hematopoietic stem cells overexpressed certain oncogenic-driver mutations. Anti-TIM-3 Ab-treatment improved survival of mice bearing leukemia with oncogene-induced TIM-3 ligand expression. Conversely, leukemia cells with low ligand expression were anti-TIM-3 treatment-resistant. In vitro, TIM-3 blockade or genetic deletion in CD8+ T cells (Tc) enhanced Tc activation, proliferation and IFN-γ production while enhancing GVL effects, preventing Tc exhaustion and improving Tc cytotoxicity and glycolysis in vivo. Conversely, TIM-3 deletion in myeloid cells did not affect allogeneic Tc proliferation and activation in vitro, suggesting that anti-TIM-3-treatment-mediated GVL effects are Tc-induced. In contrast to anti-PD-1 and anti-CTLA-4-treatment, anti-TIM-3-treatment did not enhance acute graft-versus-host-disease (aGVHD). TIM-3 and its ligands were frequently expressed in acute myeloid leukemia (AML) cells of patients with post-allo-HCT relapse. We deciphered the connection between oncogenic mutations found in AML and TIM-3 ligands expression and identify anti-TIM-3-treatment as a strategy to enhance GVL effects via metabolic and transcriptional Tc-reprogramming, without exacerbation of aGVHD. Our findings support clinical testing of anti-TIM-3 Abs in patients with AML relapse post-allo-HCT.
Nana Talvard-Balland, Lukas M. Braun, Karen O. Dixon, Melissa Zwick, Helena Engel, Alina Hartmann, Sandra Duquesne, Livius Penter, Geoffroy Andrieux, Lukas Simon Rindlisbacher, Andrea Acerbis, Jule Ehmann, Christoph Köllerer, Michela Ansuinelli, Andres Rettig, Kevin Moschallski, Petya Apostolova, Tilman Brummer, Anna L. Illert, Markus A. Schramm, Yurong Cheng, Anna Köttgen, Justus Duyster, Hans D. Menssen, Jerome Ritz, Bruce R. Blazar, Melanie Boerries, Annette Schmitt Graeff, Nurefsan Sariipek, Peter van Galen, Joerg M. Buescher, Nina Cabezas-Wallscheid, Heike L. Pahl, Erika L. Pearce, Robert J. Soiffer, Catherine J. Wu, Luca Vago, Burkhard Becher, Natalie Köhler, Tobias Wertheimer, Vijay K. Kuchroo, Robert Zeiser
JCI celebrates a century of publishing scientific discoveries with a special collection highlighting major innovations in medicine and key contributing mechanistic studies.
Biological sex profoundly influences disease risk, pathogenesis, progression, and treatment, but there are persistent gaps in the study of sex differences that span all areas of medicine. Reviews in this series will examine sex as a biological variable in cancer, metabolism, cardiovascular disease, autoimmunity, and more and highlight the potential to leverage these sex differences to optimize therapies for all.
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