AbstractType 2 alveolar epithelial cells (AEC2s) function as progenitor cells in the lung. We have shown previously that failure of AEC2 regeneration results in progressive lung fibrosis in mice and is a cardinal feature of idiopathic pulmonary fibrosis (IPF). In this study, we identified a deficiency of a specific zinc transporter SLC39A8 (ZIP8) in AEC2s from both IPF lungs and lungs of old mice. Loss of ZIP8 expression was associated with impaired renewal capacity of AEC2s and enhanced lung fibrosis. ZIP8 regulation of AEC2 progenitor function was dependent on SIRT1. Replenishment with exogenous zinc and SIRT1 activation promoted self-renewal and differentiation of AEC2s from lung tissues of IPF patients and old mice. Deletion of Zip8 in AEC2s in mice impaired AEC2 renewal, increased susceptibility of the mice to bleomycin injury, and the mice developed spontaneous lung fibrosis. Therapeutic strategies to restore zinc metabolism and appropriate SIRT1 signaling could improve AEC2 progenitor function and mitigate ongoing fibrogenesis.
Jiurong Liang, Guanling Huang, Xue Liu, Forough Taghavifar, Ningshan Liu, Yizhou Wang, Nan Deng, Changfu Yao, Ting Xie, Vrishika Kulur, Kristy Dai, Ankita Burman, Simon C. Rowan, S. Samuel Weigt, John Belperio, Barry Stripp, William C. Parks, Dianhua Jiang, Paul W. Noble
Subendothelial macrophage internalization of modified lipids and foam cell formation are hallmarks of atherosclerosis. Deubiquitinating enzymes (DUBs) are involved in various cellular activities; however, their role in foam cell formation is not fully understood. Here, using a loss-of-function lipid accumulation screening, we identified ubiquitin-specific peptidase 9 X-linked (USP9X) as a factor that suppressed lipid uptake in macrophages. We found that USP9X expression in lesional macrophages was reduced during atherosclerosis development in both humans and rodents. Atherosclerotic lesions from macrophage USP9X-deficient mice showed increased macrophage infiltration, lipid deposition, and necrotic core content than control apolipoprotein E-knockout (Apoe-/-) mice. Additionally, loss-of-function USP9X exacerbated lipid uptake, foam cell formation and inflammatory responses in macrophages. Mechanistically, the class A1 scavenger receptor (SR-A1) was identified as a USP9X substrate that removed the K63 polyubiquitin chain at the K27 site. Genetic or pharmacological inhibition of USP9X increased SR-A1 cell surface internalization following binding of oxidized low-density lipoprotein (ox-LDL). The K27R mutation of SR-A1 dramatically attenuated basal and USP9X knockdown-induced ox-LDL uptake. Moreover, blocking binding of USP9X to SR-A1 with a cell-penetrating peptide exacerbated foam cell formation and atherosclerosis. In this study, we identified macrophage USP9X as a beneficial regulator of atherosclerosis and revealed the specific mechanisms for the development of potential therapeutic strategies for atherosclerosis.
Biqing Wang, Xuening Tang, Liu Yao, Yuxin Wang, Zhipeng Chen, Mengqi Li, Naishi Wu, Dawei Wu, Xiangchen Dai, Hongfeng Jiang, Ding Ai
PRAME is a prominent member of the cancer germline antigen family of proteins, which triggers autologous T-cell mediated immune responses. Integrative genomic analysis in diffuse large B-cell lymphoma (DLBCL) uncovered recurrent, and highly focal deletions of 22q11.22 including the PRAME gene, which were associated with poor outcome. PRAME-deleted tumors showed cytotoxic T-cell immune escape and were associated with cold tumor microenvironments. In addition, PRAME down-modulation was strongly associated with somatic EZH2 Y641 mutations in DLBCL. In turn, PRC2-regulated genes were repressed in isogenic PRAME KO lymphoma cell lines and PRAME was found to directly interact with EZH2 as a negative regulator. EZH2 inhibition with EPZ-6438 abrogated these extrinsic and intrinsic effects leading to PRAME expression and microenvironment restoration in vivo. Our data highlight multiple functions of PRAME during lymphomagenesis, and provide a preclinical rationale for synergistic therapies combining epigenetic re-programming with PRAME-targeted therapies.
Katsuyoshi Takata, Lauren C. Chong, Daisuke Ennishi, Tomohiro Aoki, Michael Yu Li, Avinash Thakur, Shannon Healy, Elena Viganò, Tao Dao, Daniel Kwon, Gerben Duns, Julie S. Nielsen, Susana Ben-Neriah, Ethan Tse, Stacy S. Hung, Merrill Boyle, Sung Soo Mun, Christopher M. Bourne, Bruce Woolcock, Adèle H. Telenius, Makoto Kishida, Shinya Rai, Allen W. Zhang, Ali Bashashati, Saeed Saberi, Gianluca D' Antonio, Brad H. Nelson, Sohrab P. Shah, Pamela A. Hoodless, Ari M. Melnick, Randy D. Gascoyne, Joseph M. Connors, David A. Scheinberg, Wendy Béguelin, David W. Scott, Christian Steidl
Enhanced de novo lipogenesis mediated by sterol regulatory element-binding proteins (SREBPs) is thought to be involved in nonalcoholic steatohepatitis (NASH) pathogenesis. In this study, we assessed the impact of SREBP inhibition on NASH and liver cancer development in murine models. Unexpectedly, SREBP inhibition via deletion of the SREBP cleavage-activating protein (SCAP) in the liver exacerbated liver injury, fibrosis, and carcinogenesis, despite markedly reduced hepatic steatosis. These phenotypes were ameliorated by restoring SREBP function. Transcriptome and lipidome analyses revealed that SCAP–SREBP pathway inhibition altered the fatty acid (FA) composition of phosphatidylcholines due to both impaired FA synthesis and disorganized FA incorporation into phosphatidylcholine via lysophosphatidylcholine acyltransferase 3 (LPCAT3) downregulation, which led to endoplasmic reticulum (ER) stress and hepatocyte injury. Supplementation of phosphatidylcholines significantly improved liver injury and ER stress induced by SCAP deletion. The activity of SCAP-SREBP-LPCAT3 axis was found inversely associated with liver fibrosis severity in human NASH. SREBP inhibition also cooperated with impaired autophagy to trigger liver injury. Thus, excessively strong and broad lipogenesis inhibition was counterproductive for NASH therapy, which will have important clinical implications in NASH treatment.
Satoshi Kawamura, Yuki Matsushita, Shigeyuki Kurosaki, Mizuki Tange, Naoto Fujiwara, Yuki Hayata, Yoku Hayakawa, Nobumi Suzuki, Masahiro Hata, Mayo Tsuboi, Takahiro Kishikawa, Hiroto Kinoshita, Takuma Nakatsuka, Masaya Sato, Yotaro Kudo, Yujin Hoshida, Atsushi Umemura, Akiko Eguchi, Tsuneo Ikenoue, Yoshihiro Hirata, Motonari Uesugi, Ryosuke Tateishi, Keisuke Tateishi, Mitsuhiro Fujishiro, Kazuhiko Koike, Hayato Nakagawa
Virus-specific CD8+ T cells play a central role in HIV-1 natural controllers to maintain suppressed viremia in the absence of antiretroviral therapy. These cells display a memory program that confers them stemness properties, high survival, polyfunctionality, proliferative capacity, metabolic plasticity, and antiviral potential. The development and maintenance of such qualities by memory CD8+ T cells appear crucial to achieving natural HIV-1 control. Here we show that targeting the signaling pathways Wnt/TCF-1 and mTORC through GSK3 inhibition to reprogram HIV-specific CD8+ T cells from non-controllers promoted functional capacities associated with natural control of infection. Features of such reprogrammed cells included the enrichment in TCF-1+ less-differentiated subsets, superior response to antigen, enhanced survival, polyfunctionality, metabolic plasticity, less mTORC1-dependency, improved response to γ-chain cytokines and stronger HIV suppressive capacity. Thus, such CD8+ T cell reprogramming, combined with other available immunomodulators, might represent a promising strategy for adoptive cell therapy in the search for an HIV-1 cure.
Federico Perdomo-Celis, Caroline Passaes, Valérie Monceaux, Stevenn Volant, Faroudy Boufassa, Pierre de Truchis, Morgane Marcou, Katia Bourdic, Laurence Weiss, Corinne Jung, Christine Bourgeois, Cécile Goujard, Laurence Meyer, Michaela Müller-Trutwin, Olivier Lambotte, Asier Sáez-Cirión
Ischemic stroke prompts a strong inflammatory response which is associated with exacerbated outcomes. In this study, we investigated mechanistic regulators of neutrophil extracellular trap (NET) formation in stroke and if they contribute to stroke outcomes. NET forming neutrophils were found throughout brain tissue of ischemic stroke patients and elevated plasma NET biomarkers correlated with worse stroke outcomes. Additionally, we observed increased plasma and platelet surface expressed high mobility group box 1 (HMGB1) in stroke patients. Mechanistically, platelets were identified as the critical source for HMGB1 causing NETs in the acute phase of stroke. Depleting platelets or platelet-specific knockout of HMGB1 significantly reduced plasma HMGB1 and NET levels after stroke, and greatly improved stroke outcomes. We subsequently investigated the therapeutic potential of neonatal NET inhibitory factor (nNIF) in stroke. Mice treated with nNIF had smaller brain infarcts, improved long-term neurological and motor function, and enhanced survival after stroke. nNIF specifically blocked NET formation without affecting neutrophil recruitment after stroke. Importantly, nNIF also improved stroke outcomes in diabetic and aged mice and was still effective when given 1 hour after stroke onset. These results support a pathological role for NETs in ischemic stroke and warrant further investigation of nNIF for stroke therapy.
Frederik Denorme, Irina Portier, John L. Rustad, Mark J. Cody, Claudia V. de Araujo, Chieko Hoki, Matthew D. Alexander, Ramesh Grandhi, Mitchell R. Dyer, Matthew D. Neal, Jennifer J. Majersik, Christian C. Yost, Robert A. Campbell
BACKGROUND. It is unclear whether the level of serum hepatitis B virus (HBV) DNA at baseline impacts the on-treatment risk of hepatocellular carcinoma (HCC) in HBeAg positive, non-cirrhotic patients with chronic hepatitis B (CHB). METHODS. We conducted a multicenter cohort study including 2,073 entecavir- or tenofovir-treated, HBeAg-positive, non-cirrhotic, adult CHB patients with baseline HBV DNA levels ≥5.00 log10 IU/mL at three centers in Korea between January 2007 and December 2016. We evaluated the on-treatment incidence rate of HCC by baseline HBV DNA levels. RESULTS. During a median 5.7 years of continuous antiviral treatment, 47 patients developed HCC (0.39 per 100 person-years). By Kaplan–Meier analysis, HCC risk was the lowest in those with baseline HBV DNA levels ≥8.00 log10 IU/mL, increased incrementally with decreasing viral load, and the highest with HBV DNA levels 5.00–5.99 log10 IU/mL (P<0.001). By multivariable analysis, baseline HBV DNA level was an independent factor that was inversely associated with HCC risk. Compared with HBV DNA ≥8.00 log10 IU/mL, the adjusted hazard ratios for HCC risk with HBV DNA 7.00–7.99 log10 IU/mL, 6.00–6.99 log10 IU/mL, and 5.00–5.99 log10 IU/mL were 2.48 (P=0.03), 3.69 (P=0.002), and 6.10 (P<0.001), respectively. CONCLUSION. On-treatment HCC risk increased incrementally with decreasing baseline HBV DNA levels in the range of ≥5.00 log10 IU/mL in HBeAg-positive, non-cirrhotic, adult patients with CHB. Early initiation of antiviral treatment with a high viral load (≥8.00 log10 IU/mL) may maintain the lowest risk of HCC in those patients. FUNDING. Korean Government.
Won-Mook Choi, Gi-Ae Kim, Jonggi Choi, Seungbong Han, Young-Suk Lim
BACKGROUND. Tuberous Sclerosis Complex (TSC) is a neurogenetic syndrome due to loss-of-function mutations in TSC2 or TSC1, characterized by tumors at multiple body sites, including facial angiofibroma (FAF). Here, an ultrasensitive assessment of the extent and range of UV-induced mutations in TSC facial skin was performed. METHODS. A Multiplex High-sensitivity PCR Assay (MHPA) was developed, enabling mutation detection at extremely low (<0.1%) variant allele frequencies (VAF). RESULTS. MHPA assays were developed for both TSC2 and TP53, and applied to 81 samples, including 66 skin biopsies. UV-induced second hit mutation causing inactivation of TSC2 was pervasive in TSC facial skin with an average of 4.8 mutations per 2 mm biopsy at median VAF 0.08%, generating >150,000 incipient facial tumors (subclinical ‘micro-FAFs’) in the average TSC subject. The MHPA analysis also led to the identification of a refined UV-related indel signature and a recurrent complex mutation pattern, consisting of both a single or dinucleotide variant, and a 1-9 nt deletion, in cis. CONCLUSION. TSC facial skin can be viewed as harboring a patchwork of clonal fibroblast proliferations (micro-FAF) with indolent growth, a small proportion of which develop into clinically observable FAF. Our observations also expand the spectrum of UV-related mutation signatures. FUNDING. This work was supported by the TSC Alliance, Engles Family Fund for Research in TSC and LAM, and National Institutes of Health, National Heart, Lung, and Blood Institute [U01HL131022-04; Intramural Research Program].
Katarzyna Klonowska, Joannes M. Grevelink, Krinio Giannikou, Barbara A. Ogorek, Zachary T. Herbert, Aaron R. Thorner, Thomas N. Darling, Joel Moss, David J. Kwiatkowski
Pericytes (PC) are abundant yet remain the most enigmatic and ill-defined cell population in the heart. Here, we investigated if PC can be reprogrammed to aid neovascularization. Primary PC from human and mouse hearts acquired cytoskeleton proteins typical of vascular smooth muscle cells (VSMC) upon exclusion of EGF/bFGF, which signal through ERK1/2, or exposure to the MEK-inhibitor PD0325901. Differentiated PC became more proangiogenic, more responsive to vasoactive agents, and insensitive to chemoattractants. RNA-Sequencing revealed transcripts marking the PD0325901-induced transition into proangiogenic, stationary VSMC-like cells, including the unique expression of two angiogenesis-related markers, aquaporin 1 (AQP1) and cellular retinoic acid-binding protein 2 (CRABP2), which were further verified at the protein level. This enabled us to trace PC during in vivo studies. In mice, implantation of Matrigel plugs containing human PC+PD0325901 promoted the formation of α-SMApos neovessels compared with PC only. Two-week oral administration of PD0325901 to mice increased the heart arteriolar density, total vascular area, arteriole coverage by PDGFRβposAQP1posCRABP2pos PC, and myocardial perfusion. Short-duration PD0325901 treatment of mice after myocardial infarction enhanced the peri-infarct vascularization, reduced the scar, and improved systolic function. In conclusion, myocardial PC have intrinsic plasticity that can be pharmacologically modulated to promote reparative vascularization of the ischemic heart.
Elisa Avolio, Rajesh Katare, Anita C. Thomas, Andrea Caporali, Daryl Schwenke, Michele Carrabba, Marco Meloni, Massimo Caputo, Paolo Madeddu
Nonalcoholic fatty liver disease (NAFLD), the most common liver disease has become a silent worldwide pandemic. The incidence of NAFLD correlates with the rise in obesity, type 2 diabetes and metabolic syndrome. A hallmark feature of NAFLD is excessive hepatic fat accumulation or steatosis, due to dysregulated hepatic fat metabolism which can progress to nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Currently, there are no approved pharmacotherapies to treat this disease. Here we have identified that activation of the kisspeptin receptor (KISS1R) signaling pathway has therapeutic effects in NAFLD. Using high fat diet-fed mice, we demonstrated that a deletion of hepatic Kiss1r exacerbated hepatic steatosis. In contrast, enhanced stimulation of KISS1R protected against steatosis in wild-type C57BL/6J mice and decreased fibrosis using a diet-induced mouse model of NASH. Mechanistically, we found that hepatic KISS1R signaling activates the master energy regulator, AMPK, to thereby decrease lipogenesis and progression to NASH. In NAFLD patients and in HFD-fed mice, hepatic KISS1/KISS1R expression and plasma kisspeptin levels were elevated, suggesting a compensatory mechanism to reduce triglyceride synthesis. These findings establish KISS1R as a therapeutic target to treat NASH.
Stephania Guzman, Magdalena Dragan, Hyokjoon Kwon, Vanessa de Oliveira, Shivani Rao, Vrushank Bhatt, Katarzyna M. Kalemba, Ankit Shah, Vinod K. Rustgi, He Wang, Paul R. Bech, Ali Abbara, Chioma Izzi-Engbeaya, Pinelopi Manousou, Jessie Yanxiang Guo, Grace L. Guo, Sally Radovick, Waljit S. Dhillo, Fredric E. Wondisford, Andy V. Babwah, Moshmi Bhattacharya
No posts were found with this tag.