Aging
Abstract
BACKGROUND Chronic kidney disease (CKD) and hypertension share common pathophysiological pathways contributing to vascular damage, endothelial dysfunction, and physical decline, particularly in older adults with prefrailty. To evaluate the relationship among renal injury, physical performance, and frailty progression in hypertensive older adults with CKD and assess whether dapagliflozin associates with reduced frailty progression, we designed the study DAPA-FORTRESS (DAPAgliflozin and Frailty prOgression in hypeRTension and chRonic kidnEy diSeaSe).METHODS We enrolled 135 prefrail hypertensive patients with CKD aged >65 years and followed them for 1 year. After coarsened exact matching, our balanced cohort had 105 patients (52 dapagliflozin). Associations between albuminuria, estimated glomerular filtration rate (eGFR), and physical performance were analyzed using correlation and regression models. Effect of dapagliflozin on frailty progression was evaluated using multivariable logistic regression.RESULTS A significant inverse association between gait speed and albuminuria (r2 = 0.48, P < 0.0001) and significant positive linear association between gait speed and eGFR (r2 = 0.18; P < 0.0001) were observed. Patients with eGFR <60 mL/min/1.73 m2 exhibited significantly worse physical performance than those with higher eGFR (P = 0.0003). In adjusted analyses, receiving dapagliflozin was independently associated with lower odds of progressing to frailty at 1 year (OR = 0.130; CI 0.045–0.381; P < 0.001).CONCLUSION In older hypertensive patients with CKD, greater renal injury is associated with worse physical performance, while dapagliflozin use reduces the risk of frailty progression. These findings indicate a potential protective role of sodium–glucose cotransporter 2 inhibition in mitigating functional decline in this high-risk population.FUNDING NIH: National Heart, Lung, and Blood Institute (R01-HL146691), National Institute of Diabetes and Digestive and Kidney Diseases (R01-DK123259); American Heart Association (AHA- 24IPA1268813, AHA-22-915561, AHA-24-1195524).
Authors
Pasquale Mone, Davide Viggiano, Antonella Pansini, Maria Virginia Soldovieri, Giada Sabatelli, Valeria Visco, Gaetano Macina, Eugenio Boccalone, Michele Ciccarelli, Giuseppe Martinelli, Marco Di Mauro, Carmine Vecchione, Maria Morgante, Fahimeh Varzideh, Germano Guerra, Gaetano Santulli
Abstract
Transmembrane protein 175 (TMEM175), implicated in Parkinson’s disease (PD) risk, has been variably proposed to function as a background K+ “leak” channel or a proton-activated proton channel in lysosomes. Here, we identified the rare TMEM175 variant p.L275R in a patient with early onset PD. Electrophysiological analyses revealed that TMEM175-L275R mutant proteins retain normal lysosomal expression and K+ “leak” activity, but specifically lose proton- and agonist-dependent activation gating. In skin fibroblasts isolated from the patient with PD harboring the monoallelic p.L275R mutation (TMEM175+/L275R), and in derived induced pluripotent stem cells and induced dopaminergic neurons, lysosomal H+ flux, acidification, and degradation were impaired. These lysosomal defects were corrected upon genome editing to produce the isogenic WT allele (+/+Cor), but appeared when the mutant allele was introduced onto a WT background (+/L275RMut). Pathological α-synuclein aggregation was facilitated in patient-derived (+/L275R) and mutation-introduced (+/L275RMut) neurons. Consistent with these genetic findings, pharmacological activation of TMEM175 with small-molecule agonists restored lysosomal functions and reduced α-synuclein aggregation in TMEM175+/L275R neurons. In in-vivo studies, equivalent-site–mutation knock-in mice demonstrated synucleinopathy and PD-like motor phenotypes. Collectively, our work provides genetic and pharmacological evidence that severe loss-of-function mutations may contribute causally to the onset age and pathogenesis of PD and identifies lysosomal proton channels and transporters as potential therapeutic targets for PD intervention.
Authors
Xiaotong Yang, Ping Li, Man Lv, Lingyong Wang, Ruyi Shan, Zikai Jiang, Danzhen Chen, Fangqian Huang, Weijie Cai, Liding Zhao, Zuoyou Guo, Xinhui Chen, Zhidong Cen, Yichang Wang, Wei Yang, Xinran Li, Wei Luo, Lin Yang, Meiqin Hu, Haoxing Xu
Abstract
Aging occurs heterogeneously across organs, leading to progressive tissue dysfunction. Cellular senescence is a stress response triggered by age-associated insults, yet the mechanisms regulating senescence and organ aging remain incompletely understood. Here, we defined a role for lysine-specific demethylase 1 (LSD1) in DNA damage–mediated senescence and organ aging. LSD1 was upregulated in aged organs and senescent cells. In response to natural aging or ionizing radiation–induced DNA damage, LSD1 interacted with and demethylated ATM at lysine 3,016, as confirmed using a newly generated ATM-K3016me antibody. This modification sustained ATM phosphorylation, amplified DNA damage signaling, and delayed checkpoint recovery, promoting senescence and organ aging. Inhibition of LSD1 accelerated ATM dephosphorylation via WIP1, enhanced DNA repair, reduced senescence and DNA damage, and prevented irradiation-induced hair graying. Elimination of senescent cells with senolytics reduced LSD1 protein in aged organs, indicating a feedback loop between LSD1 and senescence. Mechanistically, LSD1 underwent autophagosome-lysosome degradation through interaction with LC3 and Beclin1, and autophagy impairment during DNA damage contributed to LSD1 accumulation in senescent cells. This study revealed LSD1 as a key regulator of DNA damage–induced senescence and organ aging and suggested that targeting LSD1 may attenuate senescence, delay organ aging, and prevent hair graying.
Authors
Yingying Zhang, Chen Yu, Xiaoqin Zhang, Linda Xiaoyan Li, Alice Shasha Cheng, Xiaogang Li
Abstract
Sarcopenia is the age-related loss of muscle strength and size that leads to mobility limitations and loss of independence in older adults. The underlying cellular mechanisms remain unclear, and treatments are limited. As the critical interface between the nervous system and muscle, the neuromuscular junction (NMJ) is essential for muscle activation and force production. Here, we demonstrate that weak older individuals exhibit NMJ transmission failure that correlates with muscle weakness severity. Preclinical experiments showed similar NMJ transmission failure in aged rodents that was associated with localized loss of muscle fiber excitability at the NMJ. This excitability defect, distinct from potential synaptic cholinergic transmission abnormalities, represents a novel disease mechanism of sarcopenia. Across species, immunohistochemistry identified a localized reduction in the voltage-gated sodium channel specific for skeletal muscle (NaV1.4) at the post-synaptic NMJ membrane. Acute NaV1.4 inhibition with μ-conotoxin GIIIB in adult rats reproduced findings of NMJ transmission failure observed in aged rodents and humans. Finally, ClC-1 chloride ion channel inhibition enhanced muscle excitability and improved NMJ transmission and muscle function in old rodents. Together, these findings demonstrate that NMJ transmission deficits are a key, reversible driver of sarcopenia and reveal a novel therapeutic target for addressing muscle weakness in aging.
Authors
W. David Arnold, Jeanette Jeppesen Morgen, Pernille Bogetofte Thomasen, Martin Broch-Lips, Leatha A. Clark, Thomas Groennebaek, Martin Skov, Jeppe Blichfeldt Winther, Abdullah F. Ramadan, Philippa A. Rust, Jessica H. Myers, Fereshteh B. Darvishi, Anna R. Dashtmian, Lauren A. Fish, Deepti Chugh, Jane Bold, Jorge A. Quiroz, John Hutchison, Hiroshi Nishimune, Ross A. Jones, Xueyong Wang, Justin R. Fallon, Thomas H. Gillingwater, Mark M. Rich, Thomas Holm Pedersen, Brian C. Clark
Abstract
Intervertebral disc degeneration (IVDD) is a leading cause of low back pain, yet clinically, there remains no effective therapeutic approach to reverse its progression, imposing a substantial socioeconomic burden. While multiple factors contribute to IVDD pathogenesis, cellular senescence has emerged as a critical risk factor associated with both the incidence and progression of IVDD. Ageing and other damage factors drive nucleus pulposus cells (NPCs) towards a senescent phenotype characterized by increased secretion of proinflammatory factors, resulting in NPC dysfunction and tissue degeneration, which are hallmarks of IVDD. In this study, we demonstrated that PRMT2 deficiency disrupted arginine methylation‒ubiquitination crosstalk, driving NPC inflammatory senescence and accelerating IVDD progression. Mechanistically, PRMT2 loss reduced FBXO7 methylation at Arg 504, promoting the FBXO7-MED12 interaction to facilitate MED12 ubiquitination and subsequent proteasomal degradation. MED12 deficiency induced pathological R-loop accumulation, which activated the cytosolic DNA-sensing cGAS-STING axis, triggering inflammatory response cascades. Notably, engineered extracellular vesicles (EVs) delivering MED12-overexpressing plasmids effectively inhibited NP cell senescence and attenuated IVDD progression. Together, our findings establish that dysregulated methylation‒ubiquitination crosstalk critically drives IVDD progression and reveal MED12 as a promising therapeutic target for ameliorating the impact of IVDD.
Authors
Huaizhen Liang, Dingchao Zhu, Zhi Du, Xinyu Li, Rui Shi, Jie Lei, Bide Tong, Hanpeng Xu, Di Wu, Xingyu Zhou, Yifan Du, Zixuan Ou, Junyu Wei, Shuchang Peng, Wencan Ke, Zhiwei Liao, Bingjin Wang, Kun Wang, Xiaobo Feng, Yu Song, Cao Yang
Abstract
Dominant mutations in Progranulin (GRN) gene cause frontotemporal lobar degeneration (FTLD-GRN), whereas homozygous GRN mutations lead to neuronal ceroid lipofuscinosis, a childhood neurodegenerative disorder. While recent transcriptomic studies reveal profound glial and neuronal pathology in FTLD-GRN at the disease end stage, the mechanism that disrupts glia-neuron homeostasis remains unclear. Using induced pluripotent stem cell (iPSC)-derived cortical organoids, we showed that GRN-/- and GRNR493X mutations lead to precocious astrogliosis that promotes neuronal stress and synaptic loss. Single-cell transcriptomics and histopathology analyses revealed a robust activation in TGFb signaling pathway in GRN-/- and GRNR493X/R493X astrocytes, which was accompanied by features of immune activation, loss of synaptic support, and abundant pTDP-43+ fibrils in astroglial cytoplasm, a feature characteristic of FTLD-GRN. Intriguingly, blocking TGFb signaling mitigated astroglial activation and pTDP-43 proteinopathy in GRN-/- organoids. Together, these results provide new insights into the cell-autonomous role of astroglial activation in neurodegeneration caused by Progranulin deficiency.
Authors
Arren C. Ramsey, Xiao-Yan Tang, Magdalena J. Macias, Patricia R. Nano, Rufei Lu, Brian Benito, Cameron M. Lau, Jisu Park, Jiasheng Zhang, Wandy Beatty, Tanzila Mukhtar, Arnold R. Kriegstein, Aparna Bhaduri, Elise Marsan, Eric J. Huang
Abstract
BACKGROUND. Approaches to achieving antiretroviral therapy (ART)-free remission from HIV-1 must consider that people over 50 years now comprise the majority of people with HIV (PWH) on ART in various regions, including the U.S. METHODS. We report a double-blind, randomized trial in which PWH on ART, aged 21-60 years, received modified vaccinia Ankara (MVA)-vectored vaccines, MVA.tHIVconsv3 (M3) and MVA.tHIVconsv4 (M4), either alone or in combination (n=7/group) or saline placebo (n=3). M3 and M4 contain complementary HIVconsvX immunogens that each span the same regions in HIV-1 Gag and Pol but differ at approximately 8% at the amino acid level. RESULTS. M3, M4, and M3M4 regimens were well tolerated and all significantly increased both the frequency (peak median increase ~3-fold) and breadth of the HIVconsvX-specific T-cell response while redirecting T cells to target conserved regions in HIV-1 for up to 10 weeks post-vaccination. We also demonstrated that vaccination increased frequencies of T-cells targeting participant autologous HIV-1 sequences. Vaccination mostly expanded pre-existing HIV-1-specific T cells, did not impact CD4 T-cell activation, low-level viremia, or integrated HIV-1 provirus. Linear regression indicated that age was independently and negatively associated with the change in T-cell frequency at 1-, 2- and 10-weeks after vaccination (~1.41-fold decrease per 10 years older). After adjusting for age, years on ART was positively associated with HIVconsvX-specific T-cell frequencies at 1- and 2-weeks following vaccination. CONCLUSION. In PWH receiving ART, MVA.HIVconsvX vaccines significantly increased T cells targeting conserved regions of HIV-1. Novel strategies may be required to enhance anti-HIV-1 immunity in older adults. TRIAL REGISTRATION. NCT03844386.
Authors
Cynthia L. Gay, Yinyan Xu, Ann Marie K. Weideman, Fiona R. Shaw, JoAnn D. Kuruc, Shayla Z. Conrad, Sofia A. Mariano, Shahryar Samir, Sallay Kallon, Alexis T. Sponaugle, Joanna A. Warren, Genevieve T. Clutton, Maria Abad-Fernandez, Carolina Kapper, Alex B. Bradley, Caroline E. Baker, Susan M. Pedersen, Matthew Moeser, Lauren Burke, Edmund G.T. Wee, Alison Crook, Gregory M. Laird, Joshua C. Cyktor, John W. Mellors, Shuntai Zhou, Lawrence Fox, Joe J. Eron, David M. Margolis, Michael G. Hudgens, Tomáš Hanke, Nilu Goonetilleke
Abstract
Huntington’s disease (HD) is a fatal neurodegenerative disorder characterized by progressive motor dysfunction, cognitive decline, and striatal neuron degeneration, primarily affecting medium spiny neurons (MSNs). Despite extensive research, the underlying metabolic vulnerabilities contributing to HD pathogenesis remain poorly understood. In this study, we employ RNA sequencing (RNA-seq) and metabolomics analyses to identify marked dysregulation of one-carbon metabolism in HD. We validate that SHMT2, a key mitochondrial enzyme in the mitochondrial one-carbon (mt-1C) pathway, is substantially downregulated in HD patient-derived iPSC-differentiated human striatal organoids (hSOs) and YAC128 mice. Functionally, pharmacological inhibition or genetic deletion of SHMT2 exacerbates mutant huntingtin (mHTT) aggregation, induces MSN degeneration in hSOs, and impairs motor function in WT mice. Conversely, SHMT2 overexpression attenuates MSN degeneration in HD-hSOs and improves motor performance in YAC128 mice. Mechanistically, SHMT2 deficiency leads to homocysteine (HCY) accumulation, which interacts with AARS1 and suppresses histone lactylation, thereby perturbing transcriptional regulation and associating with neurodegenerative phenotypes. Finally, we demonstrate that the HD clinical drug haloperidol modulates SHMT2 expression and restores histone lactylation, providing a pharmacological tool to probe SHMT2-dependent metabolic and epigenetic regulation in HD models. These findings highlight a metabolic-epigenetic axis as a promising therapeutic target for HD.
Authors
Mingqin Lu, Kexin Li, Shanshan Wu, Zhilong Zheng, Xinyue Li, Shengda Wang, Hanwen Yu, Chunyue Liu, Yueqing Jiang, Xueqin Song, Yan Liu, Xing Guo
Abstract
Aortic aneurysms are age-linked aortic dilations that progress silently and carry high rupture mortality. Immune cells are recognized drivers of aneurysm pathogenesis. Clonal hematopoiesis is an age-related expansion of somatically mutated hematopoietic stem cells that reshapes immune function and contributes to diverse age-associated diseases. However, its contribution to aneurysm pathogenesis remains unclear. In this study, targeted ultradeep sequencing of patient specimens revealed a high prevalence of clonal hematopoiesis-associated mutations that correlated with faster aneurysm expansion. Thus, we modeled clonal hematopoiesis by competitively transplanting Tet2-deficient bone marrow into ApoE-knockout mice and induced aneurysms with angiotensin II. Tet2-clonal hematopoiesis mice developed significantly greater aortic dilation than controls. Interestingly, Tet2-deficient macrophages adopted an ACP5-positive, osteoclast-like state and produced more MMP9. Both genetic and pharmacological inhibition of osteoclast-like differentiation suppressed the Tet2-mediated aneurysmal growth in vivo. Thus, Tet2-driven clonal hematopoiesis accelerates aortic aneurysm progression through MMP9-producing osteoclast-like macrophages and therefore represents a tractable therapeutic axis.
Authors
Jun Yonekawa, Yoshimitsu Yura, Junmiao Luo, Katsuhiro Kato, Shuta Ikeda, Yohei Kawai, Tomoki Hattori, Ryotaro Okamoto, Mari Kizuki, Emiri Miura-Yura, Keita Horitani, Kyung-Duk Min, Takuo Emoto, Hiroshi Banno, Mikito Takefuji, Kenneth Walsh, Toyoaki Murohara
Abstract
Aging commonly causes decline of testosterone or estrogen, leading to overaccumulation of fatness in males or females, respectively. Although such phenomenon can be readily explained by estrogen’s direct action on adipocytes in females, accumulative evidence does not support the direct action of testosterone in adipocyte lipid metabolism, suggesting that there is a missing intermediary link. Herein, we propose that glycoprotein hormone β5 (GPHB5) is the intermediary linkage between testosterone and the regulation of adiposity. In clinical samples, blood levels of GPHB5 were correlated negatively with men’s ages, and positively with circulating testosterone. Testosterone directly stimulated the expression of GPHB5 in cultured cells, pharmacological blockade of androgen receptor (AR) functions abrogated such effect. Knockout of AR led to not only development of obesity but also reduction of GPHB5 expression. Genetic ablation of GPHB5 in the males, but not in the females, lowered the browning of white adipose tissue, diminished energy expenditure and caused severe obesity. Importantly, elevated blood testosterone didn’t exert its catabolic actions in GPHB5 null mice, and yet, recombinant GPHB5 protein was able to stimulate energy expenditure and reduce adiposity. Taken together, these results provided the strong proof that GPHB5 is the “missing” intermediary hormone linking testosterone (and aging) and its well-known catabolic effect on adipose tissue.
Authors
Gengmiao Xiao, Aijun Qian, Zhuo Gao, Tingting Dai, Hui Liang, Shuai Wang, Mulan Deng, Yunjing Yan, Xindan Zhang, Xuedi Zhang, Yunping Mu, Jiqiu Wang, Aibo Gao, Huijie Zhang, Fanghong Li, Allan Zijian Zhao
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ISSN: 0021-9738 (print), 1558-8238 (online)