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.
Cardiovascular disease is the major cause of morbidity and mortality in breast cancer survivors. Chemotherapy contributes to this risk. We aimed to define the mechanisms of long-term vascular dysfunction caused by neoadjuvant chemotherapy (NACT) and identify novel therapeutic targets. We studied arteries from postmenopausal women who had undergone breast cancer treatment using docetaxel, doxorubicin and cyclophosphamide (NACT), and women with no history of such treatment matched for key clinical parameters. Mechanisms were explored in wild-type and Nox4-/- mice and human microvascular endothelial cells. Endothelium-dependent vasodilatation is severely impaired in patients after NACT, while endothelium-independent responses remain normal. This was mimicked by 24-hour exposure of arteries to NACT agents ex-vivo. When applied individually, only docetaxel impaired endothelial function in human vessels. Mechanistic studies showed that NACT increased inhibitory eNOS phosphorylation of threonine 495 in a ROCK-dependent manner and augmented vascular superoxide and hydrogen peroxide production and NADPH oxidase activity. Docetaxel increased expression of NADPH oxidase NOX4 in endothelial and smooth muscle cells and NOX2 in the endothelium. NOX4 increase in human arteries may be mediated epigenetically by diminished DNA methylation of the NOX4 promoter. Docetaxel induced endothelial dysfunction and hypertension in mice. These were prevented in Nox4-/- and by pharmacological inhibition of Nox4 or Rock. Commonly used chemotherapeutic agents, and in particular, docetaxel, alter vascular function by promoting inhibitory phosphorylation of eNOS and enhancing ROS production by NADPH oxidases.
Piotr Szczepaniak, Mateusz Siedlinski, Diana Hodorowicz-Zaniewska, Ryszard Nosalski, Tomasz P. Mikolajczyk, Aneta M. Dobosz, Anna Dikalova, Sergey Dikalov, Joanna Streb, Katarzyna Gara, Pawel Basta, Jaroslaw Krolczyk, Joanna Sulicka-Grodzicka, Ewelina Jozefczuk, Anna Dziewulska, Blessy Saju, Iwona Laksa, Wei Chen, John Dormer, Maciej Tomaszewski, Pasquale Maffia, Marta Czesnikiewicz-Guzik, Filippo Crea, Agnieszka Dobrzyn, Javid Moslehi, Tomasz Grodzicki, David G. Harrison, Tomasz J. Guzik
Functional constipation (FC) with intractable nature is the most severe form of constipation, but its etiology has long been unknown. In light of the intractable nature, we hypothesized that such intractable FC (IFC) sufferers were caused by intractable infection of a pathogenic bacterium. Here, we isolated a bacterium of Shigella sp. PIB from IFC patients that significantly inhibited the peristaltic contraction of colon by production of docosapentaenoic acid (DPA). PIB could colonize mice at least for six months. Oral administration of PIB was sufficient to induce constipation, which was reversed by PIB-specific phages. The mutated PIB with reduced DPA was incapable of inhibiting colonic function and inducing constipation, suggesting that DPA produced by PIB was the key mediator for the genesis of constipation. The PIB were detected in stools of 56% (38/68) of the IFC patients, but not in non-IFC or healthy populations (0/180). DPA levels in stools were elevated in 44.12% (30/68) of the IFC patients, but none of the healthy volunteers (0/97). Our results suggest Shigella sp. PIB may be the critical causative pathogen for IFC, and detections of fecal PIB bacteria plus DPA may be reliable methods for IFC diagnosis and classification.
Xin Chen, Tian-Tian Qiu, Ye Wang, Li-Yang Xu, Jie Sun, Zhi-Hui Jiang, Wei Zhao, Tao Tao, Yu-Wei Zhou, Lisha Wei, Yeqiong Li, Yanyan Zheng, Guo-Hua Zhou, Huaqun Chen, Jian Zhang, Xiao-Bo Feng, Fangyu Wang, Ning Li, Xue-Na Zhang, Jun Jiang, Min-Sheng Zhu
Mitochondrial DNA (mtDNA) depletion/deletions syndromes (MDDS) encompass a clinically and etiologically heterogenous group of mitochondrial disorders due to impaired mtDNA maintenance. Among the most frequent causes of MDDS are defects in nucleoside/nucleotide metabolism, which is critical for synthesis and homeostasis of the deoxynucleoside triphosphate (dNTP) substrates of mtDNA replication. A central enzyme for generating dNTPs is ribonucleotide reductase, a critical mediator of de novo nucleotide synthesis composed of catalytic RRM1 subunits in complex with RRM2 or p53R2. Here, we report five probands from four families who presented with ptosis and ophthalmoplegia, plus other manifestations and multiple mtDNA deletions in muscle. We identified three RRM1 loss-of-function variants, including a dominant catalytic site variant (NP_001024.1: p.N427K) and two homozygous recessive variants at p.R381, which has evolutionarily conserved interactions with the specificity site. Atomistic molecular dynamics simulations indicate mechanisms by which RRM1 variants affect protein structure. Cultured primary skin fibroblasts of probands manifested mtDNA depletion under cycling conditions, indicating impaired de novo nucleotide synthesis. Fibroblasts also exhibited aberrant nucleoside diphosphate and dNTP pools and mtDNA ribonucleotide incorporation. Our data reveal primary RRM1 deficiency and, by extension, impaired de novo nucleotide synthesis are causes of MDDS.
Jonathan Shintaku, Wolfgang M. Pernice, Wafaa Eyaid, Jeevan B. GC, Zuben P. Brown, Marti Juanola-Falgarona, Javier Torres-Torronteras, Ewen W. Sommerville, Debby M.E.I. Hellebrekers, Emma L. Blakely, Alan Donaldson, Ingrid M.B.H. van de Laar, Cheng-Shiun Leu, Ramon Marti, Joachim Frank, Kurenai Tanji, David A. Koolen, Richard J. Rodenburg, Patrick F. Chinnery, H.J.M. Smeets, Gráinne S. Gorman, Penelope E. Bonnen, Robert W. Taylor, Michio Hirano
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
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.