Recently developed anti-migraine therapeutics targeting calcitonin gene-related peptide (CGRP) signaling are effective, though their sites of activity remain elusive. Notably, the lymphatic vasculature is responsive to CGRP signaling, but whether meningeal lymphatic vessels (MLVs) contribute to migraine pathophysiology is unknown. Mice with lymphatic vasculature deficient in the CGRP receptor (CalcrliLEC mice) treated with nitroglycerin (NTG)-mediated chronic migraine exhibit reduced pain and light avoidance compared to NTG-treated littermate controls. Gene expression profiles of lymphatic endothelial cells (LECs) isolated from the meninges of Rpl22HA/+;Lyve1Cre RiboTag mice treated with NTG revealed increased MLV-immune interactions compared to cells from untreated mice. Interestingly, the relative abundance of mucosal vascular addressin cell adhesion molecule 1 (MAdCAM1)-interacting CD4+ T cells was increased in the deep cervical lymph nodes of NTG-treated control mice but not in NTG-treated CalcrliLEC mice. Treatment of cultured hLECs with CGRP peptide in vitro induced vascular endothelial (VE)-cadherin rearrangement and reduced functional permeability. Likewise, intra cisterna magna injection of CGRP caused rearrangement of VE-Cadherin, decreased MLV uptake of cerebrospinal fluid (CSF), and impaired CSF drainage in control mice, but not in CalcrliLEC mice. Collectively, these findings reveal a previously unrecognized role for lymphatics in chronic migraine, whereby CGRP signaling primes MLVs-immune interactions and reduces CSF efflux.
Nathan P. Nelson-Maney, Laszlo Balint, Anna L.S. Beeson, D. Stephen Serafin, Bryan M. Kistner, Elizabeth S. Douglas, Aisha H. Siddiqui, Alyssa M. Tauro, Kathleen M. Caron
There is increasing need to expand availability of donor liver grafts, including steatotic livers. However, the current use of steatotic grafts in liver transplantation is less acceptable due to their higher susceptibility to ischemia-reperfusion (I/R) injury. To investigate the mechanism underlying the susceptibility of steatotic liver to I/R injury, we detected cell death markers and inflammation in clinical donor livers and animal models. We found that caspase-8-mediated hepatic apoptosis is activated in steatotic liver I/R. However, ablation of caspase-8 only slightly mitigated steatotic liver I/R injury without affecting inflammation. We further demonstrated that RIPK1 kinase induces both caspase-8-mediated apoptosis and cell death-independent inflammation. Inhibition of RIPK1 kinase significantly protects against steatotic liver I/R injury by alleviating both hepatic apoptosis and inflammation. Additionally, we found that RIPK1 activation is induced by Z-DNA binding protein 1 (ZBP1) but not the canonical TNFα pathway during steatotic liver I/R. Deletion of ZBP1 substantially decreases the steatotic liver I/R injury. Mechanistically, ZBP1 is amplified by palmitic acid-activated JNK pathway in steatotic livers. Upon I/R, excessive reactive oxygen species trigger ZBP1 activation by inducing its aggregation independent of the Z-nucleic acids sensing action in steatotic livers, leading to the kinase activation of RIPK1 and the subsequent aggravation of liver injury. Thus, ZBP1-mediated RIPK1-driven apoptosis and inflammation exacerbate steatotic liver I/R injury, which could be targeted to protect steatotic donor livers during transplantation.
Ran Liu, Huan Cao, Shuhua Zhang, Mao Cai, Tianhao Zou, Guoliang Wang, Di Zhang, Xueling Wang, Jianjun Xu, Shenghe Deng, Tongxi Li, Daichao Xu, Jinyang Gu
Impairment of oligodendrocytes and myelin contributes to neurological disorders including multiple sclerosis (MS), stroke and Alzheimer's disease. Regeneration of myelin (remyelination) decreases the vulnerability of demyelinated axons, but this repair process commonly fails with disease progression. A contributor to inefficient remyelination is the altered extracellular matrix (ECM) in lesions that remains to be better defined. We have identified fibulin-2 (FBLN2) as a highly upregulated ECM component in lesions of MS and stroke, and in proteome databases of Alzheimer’s disease and traumatic brain injury. Focusing on MS, the inhibitory role of FBLN2 was suggested in the experimental autoimmune encephalomyelitis (EAE) model in which genetic FBLN2 deficiency improved behavioral recovery by promoting the maturation of oligodendrocytes and enhancing remyelination. Mechanistically, when oligodendrocyte progenitors were cultured in differentiation media, FBLN2 impeded their maturation into oligodendrocytes by engaging the Notch pathway, leading to cell death. Adeno-associated virus-deletion of FBLN2 in astrocytes improved oligodendrocyte numbers and functional recovery in EAE and generated new myelin profiles after lysolecithin-induced demyelination. Collectively, our findings implicate FBLN2 as a hitherto unrecognized injury-elevated ECM, and a therapeutic target, that impairs oligodendrocyte maturation and myelin repair.
Samira Ghorbani, Cenxiao Li, Brian M. Lozinski, Dorsa Moezzi, Charlotte D'Mello, Yifei Dong, Frank Visser, Hongmin Li, Claudia Silva, Mohammadparsa Khakpour, Colin J. Murray, Marie-Ève Tremblay, Mengzhou Xue, V. Wee Yong
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), a multiorgan disease that exhibits diverse metabolic defects. However, other than specific CFTR mutations, the factors that influence disease progression and severity remain poorly understood. Aberrant metabolite levels have been reported, but whether CFTR loss itself or secondary abnormalities (infection, inflammation, malnutrition, and various treatments) drive metabolic defects are uncertain. Here, we implemented comprehensive arteriovenous metabolomics in newborn CF pigs, and the results revealed CFTR as a bona fide regulator of metabolism. CFTR loss impaired metabolite exchange across organs, including disrupted lung uptake of fatty acids yet enhanced uptake of arachidonic acid, a precursor of pro-inflammatory cytokines. CFTR loss also impaired kidney reabsorption of amino acids and lactate and abolished renal glucose homeostasis. These and additional unexpected metabolic defects prior to disease manifestations reveal a fundamental role for CFTR in controlling multi-organ metabolism. Such discovery informs a basic understanding of CF, provides a foundation for future investigation, and has implications for developing therapies targeting only a single tissue.
Hosung Bae, Bo Ram Kim, Sunhee Jung, Johnny Le, Dana M. van der Heide, Wenjie Yu, Sang Hee Park, Brieanna M. Hilkin, Nicholas D. Gansemer, Linda S. Powers, Taekyung Kang, David K. Meyerholz, Victor L. Schuster, Cholsoon Jang, Michael J. Welsh
Cardiomyocyte sarcomeres contain localized ribosomes, but the factors responsible for their localization and the significance of localized translation are unknown. Using proximity labeling, we identified Ribosomal Protein SA (RPSA) as a Z-line protein. In cultured cardiomyocytes, the loss of RPSA led to impaired local protein translation and reduced sarcomere integrity. By employing CAS9 expressing mice along with adeno-associated viruses expressing CRE recombinase and single-guide RNAs targeting Rpsa, we knocked out Rpsa in vivo and observed mis-localization of ribosomes and diminished local translation. These genetic mosaic mice with Rpsa knockout in a subset of cardiomyocytes developed dilated cardiomyopathy, featuring atrophy of RPSA-deficient cardiomyocytes, compensatory hypertrophy of unaffected cardiomyocytes, left ventricular dilation, and impaired contractile function. We demonstrate that RPSA C-terminal domain is sufficient for localization to the Z-lines and that if the microtubule network is disrupted RPSA loses its sarcomeric localization. These findings highlight RPSA as a ribosomal factor essential for ribosome localization to the Z-line, facilitating local translation and sarcomere maintenance.
Rami Haddad, Omer Sadeh, Tamar Ziv, Itai Erlich, Lilac Haimovich-Caspi, Ariel Shemesh, Jolanda van der Velden, Izhak Kehat
One of the features of pathological cardiac hypertrophy is enhanced translation and protein synthesis. Translational inhibition has been shown to be an effective means of treating cardiac hypertrophy, although system-wide side effects are common. Regulators of translation, such as cardiac-specific long non-coding RNAs (lncRNAs), could provide new, more targeted, therapeutic approaches to inhibit cardiac hypertrophy. Therefore, we generated mice lacking a previously identified lncRNA named CARDINAL to examine its cardiac function. We demonstrate that CARDINAL is a cardiac-specific, ribosome associated lncRNA and show that its expression is induced in the heart upon pathological cardiac hypertrophy; its deletion in mice exacerbates stress-induced cardiac hypertrophy and augments protein translation. In contrast, overexpression of CARDINAL attenuates cardiac hypertrophy in vivo and in vitro, and suppresses hypertrophy-induced protein translation. Mechanistically, CARDINAL interacts with developmentally regulated GTP binding protein 1 (DRG1) and blocks its interaction with DRG family regulatory protein 1 (DFRP1); as a result, DRG1 is downregulated, thereby modulating the rate of protein translation in the heart in response to stress. This study provides evidence for the therapeutic potential of targeting cardiac-specific lncRNAs to suppress disease-induced translational changes and to treat cardiac hypertrophy and heart failure.
Xin He, Tinqun Yang, Yao Wei Lu, Gengze Wu, Gang Dai, Qing Ma, Mingming Zhang, Huimin Zhou, Tianxin Long, Youchen Yan, Zhuomin Liang, Chen Liu, William T. Pu, Yugang Dong, Jingsong Ou, Hong Chen, John D. Mably, Jiangui He, Da-Zhi Wang, Zhan-Peng Huang
Tumor cells are known to undergo considerable metabolic reprogramming to meet their unique demands and drive tumor growth. At the same time, this reprogramming may come at a cost with resultant metabolic vulnerabilities. The small molecule L-2-hdroxyglutarate (L-2HG) is elevated in the most common histology of renal cancer. Similar to other oncometabolites, L-2HG has the potential to profoundly impact gene expression. Here, we demonstrate that L-2HG remodels amino acid metabolism in renal cancer cells through the combined effects on histone methylation and RNA N6-methyladenosine (m6A). The combined effects of L-2HG result in a metabolic liability that renders tumors cells reliant on exogenous serine to support proliferation, redox homeostasis, and tumor growth. In concert with these data, high L-2HG kidney cancers demonstrates reduced expression of multiple serine biosynthetic enzymes. Collectively, our data indicate that high L-2HG renal tumors could be specifically targeted by strategies that limit serine availability to tumors.
Anirban Kundu, Garrett J. Brinkley, Hyeyoung Nam, Suman Karki, Richard Kirkman, Madhuparna Pandit, EunHee Shim, Hayley Widden, Juan Liu, Yasaman Heidarian, Nader H. Mahmoudzadeh, Alexander J. Fitt, Devin Absher, Han-Fei Ding, David K. Crossman, William J. Placzek, Jason W. Locasale, Dinesh Rakheja, Jonathan E. McConathy, Rekha Ramachandran, Sejong Bae, Jason M. Tennessen, Sunil Sudarshan
This study reports that targeting intrinsically disordered regions of NaV1.7 protein facilitates discovery of sodium channel inhibitory peptide aptamers (NaViPA) for adeno-associated virus (AAV)-mediated, sensory neuron-specific analgesia. A multipronged inhibition of INa1.7, INa1.6, INa1.3, and INa1.1. but not INa1.5 and INa1.8 was found for a prototype, named NaViPA1, which was derived from the NaV1.7 intracellular loop 1 and is conserved among the TTXs NaV subtypes. NaViPA1 expression in primary sensory neurons (PSNs) of dorsal root ganglia (DRG) produced significant inhibition of TTXs INa but not TTXr INa. DRG injection of AAV6-encoded NaViPA1 significantly attenuated evoked and spontaneous pain behaviors in both male and female rats with neuropathic pain induced by tibial nerve injury (TNI). Whole-cell current clamp of the PSNs showed that NaViPA1 expression normalized PSN excitability in TNI rats, suggesting that NaViPA1 attenuated pain by reversal of injury-induced neuronal hypersensitivity. Immunohistochemistry revealed efficient NaViPA1 expression restricted in PSNs and their central and peripheral terminals, indicating PSN-restricted AAV biodistribution. Inhibition of sodium channels by NaViPA1 was replicated in the human iPSC-derived sensory neurons. These results summate that NaViPA1 is a promising analgesic lead that, combined with AAV-mediated PSN-specific block of multiple TTXs NaVs, has potential as peripheral nerve-restricted analgesic therapeutics.
Seung Min Shin, Brandon Itson-Zoske, Fan Fan, Yucheng Xiao, Chensheng Qiu, Theodore R. Cummins, Quinn H. Hogan, Hongwei Yu
Newborn mammalian cardiomyocytes quickly transition from a fetal to an adult phenotype that utilizes mitochondrial oxidative phosphorylation but loses mitotic capacity. We tested whether forced reversal of adult cardiomyocytes back to a fetal glycolytic phenotype would restore proliferative capacity. We deleted Uqcrfs1 (mitochondrial Rieske Iron-Sulfur protein, RISP) in hearts of adult mice. As RISP protein decreased, heart mitochondrial function declined, and glucose utilization increased. Simultaneously, they underwent hyperplastic remodeling during which cardiomyocyte number doubled without cellular hypertrophy. Cellular energy supply was preserved, AMPK activation was absent, and mTOR activation was evident. In ischemic hearts with RISP deletion, new cardiomyocytes migrated into the infarcted region, suggesting the potential for therapeutic cardiac regeneration. RNA-seq revealed upregulation of genes associated with cardiac development and proliferation. Metabolomic analysis revealed a decrease in alpha-ketoglutarate (required for TET-mediated demethylation) and an increase in S-adenosylmethionine (required for methyltransferase activity). Analysis revealed an increase in methylated CpGs near gene transcriptional start sites. Genes that were both differentially expressed and differentially methylated were linked to upregulated cardiac developmental pathways. We conclude that decreased mitochondrial function and increased glucose utilization can restore mitotic capacity in adult cardiomyocytes resulting in the generation of new heart cells, potentially through the modification of substrates that regulate epigenetic modification of genes required for proliferation.
Gregory B. Waypa, Kimberly A. Smith, Paul T. Mungai, Vincent J. Dudley, Kathryn A. Helmin, Benjamin D. Singer, Clara Bien Peek, Joseph Bass, Lauren Beussink-Nelson, Sanjiv J. Shah, Gaston Ofman, J. Andrew Wasserstrom, William A. Muller, Alexander V. Misharin, G.R. Scott Budinger, Hiam Abdala-Valencia, Navdeep S. Chandel, Danijela Dokic, Elizabeth T. Bartom, Shuang Zhang, Yuki Tatekoshi, Amir Mahmoodzadeh, Hossein Ardehali, Edward B. Thorp, Paul T. Schumacker
Spinal Muscular Atrophy (SMA) is typically characterized as a motor neuron disease, but extra-neuronal phenotypes are present in almost every organ in severely affected patients and animal models. Extra-neuronal phenotypes were previously underappreciated as patients with severe SMA phenotypes usually died in infancy; however, with current treatments for motor neurons increasing patient lifespan, impaired function of peripheral organs may develop into significant future comorbidities and lead to new treatment-modified phenotypes. Fatty liver is seen in SMA animal models , but generalizability to patients and whether this is due to hepatocyte-intrinsic Survival Motor Neuron (SMN) protein deficiency and/or subsequent to skeletal muscle denervation is unknown. If liver pathology in SMA is SMN-dependent and hepatocyte-intrinsic, this suggests SMN repleting therapies must target extra-neuronal tissues and motor neurons for optimal patient outcome. Here we showed that fatty liver is present in SMA and that SMA patient-specific iHeps were susceptible to steatosis. Using proteomics, functional studies and CRISPR/Cas9 gene editing, we confirmed that fatty liver in SMA is a primary SMN-dependent hepatocyte-intrinsic liver defect associated with mitochondrial and other hepatic metabolism implications. These pathologies require monitoring and indicate need for systematic clinical surveillance and additional and/or combinatorial therapies to ensure continued SMA patient health.
Damien Meng-Kiat Leow, Yang Kai Ng, Loo Chien Wang, Hiromi W.L. Koh, Tianyun Zhao, Zi Jian Khong, Tommaso Tabaglio, Gunaseelan Narayanan, Richard M. Giadone, Radoslaw M. Sobota, Shi-Yan Ng, Adrian K.K. Teo, Simon H Parson, Lee L. Rubin, Wei-Yi Ong, Basil T. Darras, Crystal J.J. Yeo
No posts were found with this tag.