Avolio et al. show that cardiac pericytes have intrinsic vascular plasticity and can be pharmacologically reprogrammed using a MEK inhibitor to aid neovascularization of the ischemic heart. The cover image shows cardiomyocytes stained with α-sarcomeric actin (red) and TUNEL (green; recognizing apoptotic cell nuclei) from a mouse heart treated with a MEK inhibitor.
BACKGROUND. In human lupus nephritis (LN), tubulointerstitial inflammation (TII) on biopsy predicts progression to end-stage renal disease (ESRD). However, only about half of patients with moderate/severe TII develop ESRD. We hypothesized that this heterogeneity in outcome reflects different underlying inflammatory states. Therefore, we interrogated renal biopsies from LN longitudinal and cross-sectional cohorts. METHODS. Data was acquired using conventional and highly multiplexed confocal microscopy. To accurately segment cells across whole biopsies, and to understand their spatial relationships, we developed computational pipelines by training and implementing several deep learning models and other computer vision techniques. RESULTS. High B cell densities were associated with protection from ESRD. In contrast, CD8, γδ and other CD4-CD8- T cells, were associated with both acute renal failure and progression to ESRD. B cells were often organized into large periglomerular neighborhoods with T follicular helper cells while CD4- T cells formed small neighborhoods in the tubulointerstitium whose frequency predicted progression to ESRD. CONCLUSIONS. These data reveal that specific in situ inflammatory states are associated with refractory and progressive renal disease. FUNDING. These studies were funded by the NIH Autoimmunity Centers of Excellence (AI082724), Department of Defense (LRI180083) and Alliance for Lupus Research, NIH S10-OD025081, S10-RR021039, and P30-CA14599 awards.
Rebecca Abraham, Madeleine S. Durkee, Junting Ai, Margaret Veselits, Gabriel Casella, Yuta Asano, Anthony Chang, Kichul Ko, Charles Oshinsky, Emily Peninger, Maryellen L. Giger, Marcus R. Clark
The anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase known for its oncogenic potential and involved in the development of the peripheral and central nervous system. ALK receptor ligands, ALKAL1 and ALKAL2 were recently found to promote neuronal differentiation and survival. Here we show that inflammation or injury enhanced ALKAL2 expression in a subset of TRPV1+ sensory neurons. Notably, ALKAL2 was particularly enriched in both mice and human peptidergic nociceptors, yet weakly expressed in non peptidergic, large diameter myelinated neurons or in the brain. Using a co-culture expression system, we found that nociceptors exposed to ALKAL2 exhibited heightened excitability and neurite outgrowth. Intraplantar Complete Freund′s adjuvant (CFA) or intrathecal infusion of recombinant ALKAL2 led to ALK phosphorylation in the lumbar dorsal horn of the spinal cord. Finally, depletion of ALKAL2 in dorsal root ganglia or blocking ALK with clinically available compounds Crizotinib or Lorlatinib, reversed thermal hyperalgesia and mechanical allodynia induced by inflammation or nerve injury, respectively. Overall, our work uncovers the ALKAL2-ALK signaling axis as a central regulator of nociceptor-induced sensitization. We propose that clinically approved ALK inhibitors used for Non–Small Cell Lung Cancer and neuroblastomas, could be repurposed to treat persistent pain conditions.
Manon Defaye, Mircea C. Iftinca, Vinicius M. Gadotti, Lilian Basso, Nasser S. Abdullah, Melissa Cumenal, Francina Agosti, Ahmed Hassan, Robyn Flynn, Jeremy Martin, Vanessa Soubeyre, Gaëtan Poulen, Nicolas Lonjon, Florence Vachiery-Lahaye, Luc Bauchet, Pierre Francois Mery, Emmanuel Bourinet, Gerald W. Zamponi, Christophe Altier
DNA methyltransferase 3a (DNMT3a) is an important part of the epigenetic machinery that stabilizes patterns of activated T-cell responses. We hypothesized that donor T-cell DNMT3a regulates alloreactivity after allogeneic blood and marrow transplantation (allo-BMT). T-cell conditional Dnmt3a knock-out (KO) animals were used as donors in murine allo-BMT models. Mice receiving allo-BMT from KO donors developed severe acute graft-versus-host disease (aGVHD), with increases in inflammatory cytokine levels and organ histopathology. KO T-cells migrated and proliferated in secondary lymphoid organs earlier and demonstrated a trafficking advantage to the small intestine. Donor T-cell subsets were purified post-BMT for whole genome bisulfite sequencing (WGBS) and RNA sequencing. KO T-cells had similar global methylation to wild-type (WT), with distinct, localized areas of hypomethylation. Using a highly sensitive computational method, we produced a comprehensive profile of the altered epigenome landscape. Hypomethylation corresponded with changes in gene expression in several pathways of T-cell signaling and differentiation. Additionally, Dnmt3a KO T-cells conveyed superior graft-versus-tumor activity. Our findings demonstrate a critical role for DNMT3a in regulating T-cell alloreactivity and illuminate pathways that control T-cell tolerance. These results also provide a platform to decipher clinical data that associate donor DNMT3a mutations with increased GVHD, decreased relapse, and improved survival.
Yiouli P. Ktena, Michael A. Koldobskiy, Michael I. Barbato, Han-Hsuan Fu, Leo Luznik, Nicolas J. Llosa, Azeb Haile, Orly R. Klein, Chen Liu, Christopher J. Gamper, Kenneth R. Cooke
Acute megakaryoblastic leukemia of Down syndrome (DS-AMKL) is a model of clonal evolution from a preleukemic transient myeloproliferative disorder requiring both a trisomy 21 (T21) and a GATA1s mutation to a leukemia driven by additional driver mutations. We modelled the megakaryocyte differentiation defect through stepwise gene editing of GATA1s, SMC3+/- and MPLW515K providing 20 different trisomy or disomy 21 iPSC clones. GATA1s profoundly reshaped iPSC-derived hematopoietic architecture with gradual myeloid-to-megakaryocyte shift and megakaryocyte differentiation alteration upon addition of SMC3 and MPL mutations. Transcriptional, chromatin accessibility and GATA1 binding data showed alteration of essential megakaryocyte differentiation genes, including NFE2 downregulation that was associated with loss of GATA1s binding and functionally-involved in megakaryocyte differentiation blockage. T21 enhanced the proliferative phenotype reproducing the cellular and molecular abnormalities of DS-AMKL. Our study provides a unique array of human cell-based models revealing individual contributions of different mutations to DS-AMKL differentiation blockage, a major determinant of leukemic progression.
Brahim Arkoun, Elie Robert, Fabien Boudia, Stefania Mazzi, Virginie Dufour, Aurelie Siret, Yasmine Mammasse, Zakia Aid, Mathieu Vieira, Aygun Imanci, Marine Aglave, Marie Cambot, Rachel Petermann, Sylvie Souquere, Philippe Rameau, Cyril Catelain, Romain Diot, Gerard Tachdjian, Olivier Hermine, Nathalie Droin, Najet Debili, Isabelle Plo, Sebastien Malinge, Eric Soler, Hana Raslova, Thomas Mercher, William Vainchenker
Elevated hematocrit is associated with cardiovascular risk; however, the causality and mechanisms are unclear. The JAK2V617F (Jak2VF) mutation increases cardiovascular risk in myeloproliferative disorders and in clonal hematopoiesis (CH). Jak2VF mice with elevated white blood cells, platelets and red blood cells (RBCs) display accelerated atherosclerosis and macrophage erythrophagocytosis. To investigate whether selective erythroid Jak2VF expression promotes atherosclerosis, we developed hyperlipidemic Erythropoietin Receptor Cre mice that express Jak2VF in the erythroid lineage (VFEpoR mice). VFEpoR mice without elevated blood cell counts showed increased atherosclerotic plaque necrosis, erythrophagocytosis and ferroptosis. Selective induction of erythrocytosis with low dose erythropoietin further exacerbated atherosclerosis with prominent ferroptosis, lipid peroxidation and endothelial damage. VFEpoR RBCs had reduced antioxidant defenses and increased lipid hydroperoxides. Phagocytosis of human or murine WT or JAK2VF RBCs by WT macrophages induced ferroptosis, which was prevented by the ferroptosis inhibitor Liproxstatin-1. Liproxstatin-1 reversed increased atherosclerosis, lipid peroxidation, ferroptosis and endothelial damage in VFEpoR mice and in Jak2VF chimeric mice simulating CH, but had no impact in controls. Erythroid lineage Jak2VF expression leads to qualitative and quantitative defects in RBCs that exacerbate atherosclerosis. Phagocytosis of RBCs by plaque macrophages promotes ferroptosis, suggesting a new therapeutic target to reduce RBC-mediated cardiovascular risk.
Wenli Liu, Nataliya K. Östberg, Mustafa Yalcinkaya, Huijuan Dou, Kaori Endo-Umeda, Yang Tang, Xintong Hou, Tong Xiao, Trevor Filder, Sandra Abramowicz, Yong-Guang Yang, Oliver Soehnlein, Alan R. Tall, Nan Wang
JCI This Month is a digest of the research, reviews, and other features published each month.
Cardiovascular diseases remain a leading cause of death worldwide, and treatment is complicated by the inadequacies of available therapies. This collection of reviews, developed by Daniel P. Kelly, explores emerging strategies for treating a range of cardiac pathologies, including: recent discoveries of epigenetic regulators that can be targeted to combat cardiac fibrosis, state of the art in genome-editing therapies, interactions of the vascular endothelium with metabolic tissues, current understanding of myosin modulators, and novel targets for treating dyslipidemia. Together, the reviews provide a broad update on numerous advances in cardiovascular medicine.