Aging
Abstract
The biological age of organs may better quantify risk for health deterioration compared with chronological age. We investigated organ-specific aging patterns in a community-based cohort and assessed the associations with adverse health outcomes. Biological ages of 11 organs were estimated for 11,757 participants of the Atherosclerosis Risk in Communities (ARIC) study (55.6% women, mean age, 57.1 years) using a circulating protein–based model. Older organ ages were significantly associated with related adverse outcomes, even after accounting for chronological age; for example, older arteries and hearts were associated with an increased risk for coronary heart disease (CHD; hazard ratio [HR] per 5-year-higher age gap, 1.22; 95% CI [1.13–1.31] and 1.16 [1.07–1.26], respectively, and older lungs with lung cancer (HR 1.12 [1.09–1.16]). Hierarchical agglomerative clustering based on organ ages revealed 3 patient phenotypes: those with older organs, normal/slightly older organs, and younger organs. The patients with older organs were at higher risk for cancer (HR 1.19; 95% CI [1.08–1.31]), death (HR 1.75 [1.64–1.86]), end-stage kidney disease (HR 6.12 [4.65–8.06]), CHD (HR 1.21 [1.06–1.38]), heart failure (HR 1.92 [1.73–2.13]), infection (HR 1.56 [1.44–1.68]), and stroke (HR 1.36 [1.16–1.61]). Proteomic organ aging signatures demonstrated significant associations with multiple adverse health outcomes and may be useful for health risk identification.
Authors
Celina S. Liu, Wan-Jin Yeo, Aditya Surapaneni, B. Gwen Windham, Hamilton S.-H. Oh, Anna Prizment, Sanaz Sedaghat, Pascal Schlosser, Eugene P. Rhee, Sushrut S. Waikar, Josef Coresh, Keenan A. Walker, Morgan E. Grams
Abstract
Insulin/insulin growth factor signaling is a conserved pathway that regulates lifespan. Yet, long-lived loss-of-function mutants often produce insulin-resistance, slow growth, and impair reproduction. Recently, a gain-of-function mutation in the kinase insert domain (KID) of the Drosophila insulin/IGF receptor was seen to dominantly extend lifespan without impairing insulin-sensitivity, growth and reproduction. This substitution occurs within residues conserved in mammalian insulin receptor (IR) and insulin growth factor-1 receptor (IGF-1R). We produced two knock-in mouse strains that carry the homologous KID Arg/Cys substitution in murine IR or IGF-1R, and we replicated these genotypes in human cells. Cells with heterodimer receptors of IR or IGF-1R induce receptor phosphorylation and phospho-Akt when stimulated with insulin or IGF. Heterodimer receptors of IR fully induce pERK but ERK was less phosphorylated in cells with IGF-1R heterodimers. Adults with a single KID allele (producing heterodimer receptors) have normal growth and glucose regulation. At four months, these mice variably display hormonal markers that associate with successful aging counteraction, including elevated adiponectin, FGF21, and reduced leptin and IGF-1. Livers of IGF-1R females show decreased transcriptome-based biological age, which may point toward delayed aging and warrants an actual lifespan experiment. These data suggest that KID mutants may slow mammalian aging while they avoid the complications of insulin resistance.
Authors
Ulalume Hernández-Arciga, Jun Kyoung Kim, Jacob L. Fisher, Alexander Tyshkovskiy, Alibek Moldakozhayev, Catherine Hall, Souvik Ghosh, Yashvandhini Govindaraj, Ian J. Sipula, Jake Kastroll, Diana Cooke, Jinping Luo, Jonathan K. Alder, Stacey J. Sukoff Rizzo, Gene P. Ables, Eunhee Choi, Vadim N. Gladyshev, Michael J. Jurczak, Marc Tatar, Andrey A. Parkhitko
Abstract
Modic type 1 and 2 changes (MC-1 and MC-2) are highly prevalent in individuals with chronic low back pain, yet the cellular and molecular mechanisms underlying vertebral endplate degeneration remain poorly defined. Here, we report that osteoclastogenesis is markedly elevated in MC-1 and MC-2 lesions compared to MC-3, suggesting an active role for osteoclasts in the early stages of degeneration. Using a lumbar spine instability (LSI) mouse model, we demonstrate enhanced osteoclast activity in degenerating endplates. RNA sequencing of mononuclear cells isolated from the endplate and adjacent subchondral bone identifies Gdf15 as a potential upstream regulator of this process. Conditional knockout of Gdf15 in monocytes reduces osteoclast formation, aberrant CD31hiEmcnhi angiogenesis, and pain-associated neurogenesis, ultimately mitigating endplate degeneration and mechanical allodynia. Mechanistically, GDF15 promotes the fusion of preosteoclasts by modulating the expression of Rho-family small GTPases. In a humanized GDF15 knock-in mouse model, therapeutic neutralization of GDF15 leads to a reduction in osteoclast burden, improved endplate structure, and attenuated pain behavior. Together, these findings uncover a previously unrecognized role for GDF15 in driving osteoclast-mediated endplate degeneration and highlight its potential as a therapeutic target for the treatment of endplate-related chronic low back pain.
Authors
Xiaoqun Li, Jinhui Wu, Qingjie Kong, Miao Hu, Yuhong Li, Ziheng Wei, Heng Jiang, Xuhui Zhou, Jun Ma
Abstract
Saturated fatty acids impose lipotoxic stress on pancreatic β-cells, leading to β-cell failure and diabetes. In this study, we investigate the critical role of organellar Ca2+ disturbance on defective autophagy and β-cell lipotoxicity. Palmitate, a saturated fatty acid, induced perilysosomal Ca2+ elevation, sustained mTORC1 activation on the lysosomal membrane, suppression of the lysosomal transient receptor potential mucolipin 1 (TRPML1) channel, and accumulation of undigested autophagosomes in β-cells. These Ca2+ aberrations with autophagy defects by palmitate were prevented by an mTORC1 inhibitor or a mitochondrial superoxide scavenger. To alleviate perilysosomal Ca2+ overload, strategies such as lowering extracellular Ca2+, employing voltage-gated Ca2+ channel blocker or ATP-sensitive K+ channel opener effectively abrogated mTORC1 activation and preserved autophagy. Furthermore, redirecting perilysosomal Ca2+ into the endoplasmic reticulum (ER) with an ER Ca2+ ATPase activator, restores TRPML1 activity, promotes autophagic flux, and improves survival of β-cells exposed to palmitate-induced lipotoxicity. Our findings suggest oxidative stress-Ca2+ overload-mTORC1 pathway involvement in TRPML1 suppression and defective autophagy during β-cell lipotoxicity. Restoring perilysosomal Ca2+ homeostasis emerges as a promising therapeutic strategy for metabolic diseases.
Authors
Ha Thu Nguyen, Luong Dai Ly, Thuy Thi Thanh Ngo, Soo Kyung Lee, Carlos Noriega Polo, Subo Lee, Taesic Lee, Seung-Kuy Cha, Xaviera Riani Yasasilka, Kae Won Cho, Myung-Shik Lee, Andreas Wiederkehr, Claes B. Wollheim, Kyu-Sang Park
Abstract
A distinguishing feature of older mesenchymal stem cells (MSCs) from bone marrow (BM) is the transition in their differentiation capabilities from osteoblasts to adipocytes. However, the mechanisms underlying these cellular events during the aging process remain unclear. We identified Angiopoietin-like protein 8 (ANGPTL8), a newly found adipokine implicated in lipid metabolism, that influences the fate of MSCs in BM during skeletal aging. Our studies revealed that ANGPTL8 steered MSCs towards adipogenic differentiation, overshadowing osteoblastogenesis. Mice with overexpressed ANGPTL8 exhibited reduced bone mass and increased bone marrow adiposity, while those with transgenic depletion of ANGPTL8 showed lowered bone loss and less accumulation of bone marrow fat. ANGPTL8 influenced the bone marrow niche of MSCs by inhibiting the Wnt/β-catenin signaling pathway. Partial inhibition of PPARγ rescued some aspects of the phenotype in MSCs with ANGPTL8 overexpression. Furthermore, treatment with Angptl8-Antisense Oligonucleotide (Angptl8-ASO) improved the phenotype of aging mice. The research proposes that ANGPTL8 is a critical regulator of senesence-related changes in the BM niche and the cell fate switch of MSCs.
Authors
Yaming Guo, Zeqing Zhang, Junyu He, Peiqiong Luo, Zhihan Wang, Yurong Zhu, Xiaoyu Meng, Limeng Pan, Ranran Kan, Yuxi Xiang, Beibei Mao, Yi He, Siyi Wang, Yan Yang, Fengjing Guo, Hongbo You, Feng Li, Danpei Li, Yong Chen, Xuefeng Yu
Abstract
Alzheimer’s disease (AD) is characterized by plaques and tangles, including calcium dysregulation and glycated products produced by reactive carbonyl compounds. AD brains have increased glyoxalase I (GLO1), a major scavenger of inflammatory carbonyl compounds, at early, but not later, stages of disease. Calcium dysregulation includes calcium leak from phosphorylated ryanodine receptor 2 (pS2808-RyR2), seen in aged macaques and AD mouse models, but the downstream consequences of calcium leak remain unclear. Here, we show that chronic calcium leak is associated with increased GLO1 expression and activity. In macaque, we found age-related increases in GLO1 expression in prefrontal cortex (PFC), correlating with pS2808-RyR2, and localized to dendrites and astrocytes. To examine the relationship between GLO1 and RyR2, we used S2808D-RyR2 mutant mice exhibiting chronic calcium leak through RyR2, and found increased GLO1 expression and activity in the PFC and hippocampus as early as 1-month and as late as 21-months of age, with a bell-shaped aging curve. These aged S2808D-RyR2 mice demonstrated impaired working memory. As with macaques, GLO1 was expressed in astrocytes and neurons. Proteomics data generated from S2808D-RyR2 synaptosomes confirmed GLO1 upregulation. Altogether, these data suggest potential association between GLO1 and chronic calcium leak, providing resilience in early stages of aging.
Authors
Elizabeth Woo, Dibyadeep Datta, Shveta Bathla, Hannah E. Beatty, Pinar B. Caglayan, Ashley Kristant Albizu, TuKiet T. Lam, Jean Kanyo, Mary Kate P. Joyce, Shannon N. Leslie, Stacy Uchendu, Jonathan H. DeLong, Qinyue Stacy Guan, Jiaxin Li, Efrat Abramson, Alison L. Herman, Dawson C. Cooper, Pawel Licznerski, Tamas L. Horvath, Elizabeth A. Jonas, Angus C. Nairn, Amy F.T. Arnsten, Lauren H. Sansing
Abstract
Impaired muscle regrowth in aging is underpinned by reduced pro-inflammatory macrophage function and subsequently impaired muscle cellular remodeling. Macrophage phenotype is metabolically controlled through TCA intermediate accumulation and activation of HIF1A. We hypothesized that transient hypoxia following disuse in old mice would enhance macrophage metabolic inflammatory function thereby improving muscle cellular remodeling and recovery. Old (20 months) and young adult mice (4 months) were exposed to acute (24h) normobaric hypoxia immediately following 14-days of hindlimb unloading and assessed during early re-ambulation (4- and 7-days) compared to age-matched controls. Treated aged mice had improved pro-inflammatory macrophage profiles, muscle cellular remodeling, and functional muscle recovery to the levels of young control mice. Likewise, young adult mice had enhanced muscle remodeling and functional recovery when treated with acute hypoxia. Treatment in aged mice restored the muscle molecular fingerprint and biochemical spectral patterns (Raman Spectroscopy) observed in young mice and strongly correlated to improved collagen remodeling. Finally, intramuscular delivery of hypoxia-treated macrophages recapitulated the muscle remodeling and recovery effects of whole-body hypoxic exposure in old mice. These results emphasize the role of pro-inflammatory macrophages during muscle regrowth in aging and highlight immunometabolic approaches as a route to improve muscle cellular dynamics and regrowth.
Authors
Zachary J. Fennel, Negar Kosari, Paul-Emile Bourrant, Elena M. Yee, Robert J. Castro, Anu S. Kurian, Jonathan Palmer, Morgan Christensen, Katsuhiko Funai, Ryan M. O'Connell, Anhong Zhou, Micah J. Drummond
Abstract
Pathological cardiac remodeling is associated with the reactivation of fetal genes, yet the extent of the heart’s fetal gene program and its impact on proteome compositions remain incompletely understood. Here, using a new proteome-wide protein ratio quantification strategy with mass spectrometry, we identify pervasive isoform usage shifts in fetal and postnatal mouse hearts, involving 145 pairs of highly homologous paralogs and alternative splicing-derived isoform proteins. Proteome-wide ratio comparisons readily rediscover hallmark fetal gene signatures in muscle contraction and glucose metabolism pathways, while revealing novel isoform usage in mitochondrial and gene expression proteins, including PPA1/PPA2, ANT1/ANT2, and PCBP1/PCBP2 switches. Paralogs with differential fetal usage tend to be evolutionarily recent, consistent with functional diversification. Alternative splicing adds another rich source of fetal isoform usage differences, involving PKM M1/M2, GLS-1 KGA/GAC, PDLIM5 long/short, and other spliceoforms. When comparing absolute protein proportions, we observe a partial reversion toward fetal gene usage in pathological hearts. In summary, we present a ratiometric catalog of paralogs and spliceoform pairs in the cardiac fetal gene program. More generally, the results demonstrate the potential of applying the proteome-wide ratio test concept to discover new regulatory modalities beyond differential gene expression.
Authors
Yu Han, Shaonil Binti, Sara A. Wennersten, Boomathi Pandi, Dominic C.M. Ng, Edward Lau, Maggie P.Y. Lam
Abstract
The aryl hydrocarbon receptor (AhR) is proposed to mediate the frailty-promoting effects of the tryptophan metabolite kynurenine (Kyn), which increases with age in mice and humans. The goal of the current study was to test whether administration of pharmacological AhR inhibitors, BAY2416964 and CH-223191, could abrogate musculoskeletal decline in aging mice. Female C57BL/6 mice (18 months old) were treated with vehicle (VEH) or BAY2416964 (30 mg/kg) via daily oral gavage 5 days/week for 8 weeks. A second AhR antagonist, CH-223191, was administered to 16-month-old male and female C57BL/6 mice via intraperitoneal injections (3.3 mg/kg) 3 days/week for 12 weeks. While grip strength declined over time in VEH-treated mice, BAY2416964 preserved grip strength in part by improving integrity of neuromuscular junctions, an effect replicated during in vitro studies with siRNA against AhR. Cortical bone mass was also greater in BAY2416964- than VEH-treated mice. Similarly, CH-223191 treatment improved cortical bone and showed beneficial effects in skeletal muscle, including reducing oxidative stress as compared to VEH-treated animals. Transcriptomic and proteomic data from BAY2416964-treated mice supported a positive impact of BAY2416964 on molecular targets that affect neuromuscular junction function. Taken together, these data support AhR as a therapeutic target for improving musculoskeletal health during aging.
Authors
Kanglun Yu, Sagar Vyavahare, Dima W. Alhamad, Husam Bensreti, Ling Ruan, Anik Tuladhar, Caihong Dai, Joseph C. Shaver, Alok Tripathi, Kehong Ding, Rafal Pacholczyk, Marion A. Cooley, Roger Zhong, Maribeth H. Johnson, Jie Chen, Wendy B. Bollag, Carlos M. Isales, William D. Hill, Mark W. Hamrick, Sadanand Fulzele, Meghan E. McGee-Lawrence
Abstract
Benign prostatic hyperplasia (BPH) is the most common urologic condition in elderly men, characterized by the reactivation of developmental programs such as prostatic budding and branching. However, the molecular mechanisms underlying this reactivation in BPH remain unclear. In this study, we identified TIAM1 (T-lymphoma invasion and metastasis-inducing protein-1) as a critical regulator of prostatic budding and branching. By generating an unbiased BPH transcriptomic signature from patient datasets, we discovered an upregulation of TIAM1, which was subsequently validated at the protein level. Functional assays using organoid cultures derived from human prostatic cell lines revealed that TIAM1 is essential for prostatic budding and branching. Additionally, the BPH transcriptomic signature identified NSC23766, a small molecule inhibitor of TIAM1-RAC1 signaling, as a therapeutic proof-of-concept agent for BPH. Genetic knockdown of TIAM1 in human prostatic cell lines markedly reduced organoid branching, an effect mirrored by administration of NSC23766. The translational relevance of these findings is underscored by the growth inhibition observed in patient-derived BPH organoids treated with NSC23766. In conclusion, our findings identify TIAM1 as a key driver of prostatic branching and growth, and suggest that targeting TIAM1-RAC1 signaling could be a promising therapeutic strategy for BPH.
Authors
Hamed Khedmatgozar, Sayanika Dutta, Michael Dominguez, Murugananthkumar Raju, Girijesh Kumar Patel, Daniel Latour, Melanie Johnson, Mohamed Fokar, Irfan Warraich, Allan Haynes, Barry J. Maurer, Werner de Riese, Luis Brandi, Robert J. Matusik, Srinivas Nandana, Manisha Tripathi
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