Angiopoietin-like 8 governs osteoblast-adipocyte lineage commitment during skeletal aging

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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

Ryanodine receptor 2-mediated calcium leak is associated with increased glyoxalase I in the aging brain

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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

Macrophage metabolic rewiring rejuvenates muscle raman signatures and cellular remodeling during regrowth in aged mice

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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

A ratiometric catalog of protein isoform shifts in the cardiac fetal gene program

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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

Inhibition of AhR improves cortical bone and skeletal muscle function via preservation of neuromuscular junctions

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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

TIAM1 drives prostatic branching phenotype and is a potential therapeutic target for benign prostatic hyperplasia

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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

Loss of genome maintenance is linked to mTORC1 signaling and accelerates podocyte damage

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Abstract

DNA repair is essential for preserving genome integrity. Podocytes, post-mitotic epithelial cells of the kidney filtration unit, bear limited regenerative capacity, yet their survival is indispensable for kidney health. Podocyte loss is a hallmark of the aging process and of many diseases, but the underlying factors remain unclear. We investigated the consequences of DNA damage in a podocyte-specific knockout mouse model for Ercc1 and in cultured podocytes under genomic stress. Furthermore, we characterized DNA damage-related alterations in mouse and human renal tissue of different ages and patients suffering from minimal change disease and focal segmental glomerulosclerosis. Ercc1 knockout resulted in accumulation of DNA damage, ensuing albuminuria and kidney disease. Podocytes reacted to genomic stress by activating mTORC1 signaling in vitro and in vivo. This was abrogated by inhibiting DNA damage signaling through DNA-PK and ATM kinases and inhibition of mTORC1 modulated the development of glomerulosclerosis. Perturbed DNA repair gene expression and genomic stress in podocytes was also detected in focal segmental glomerulosclerosis. Beyond that, DNA damage signaling occurred in podocytes of healthy aging mice and humans. We provide evidence that genome maintenance in podocytes is linked to the mTORC1 pathway, involved in the aging process and the development of glomerulosclerosis.

Authors

Fabian Braun, Amrei M. Mandel, Linda Blomberg, Milagros N. Wong, Georgia Chatzinikolaou, David H. Meyer, Anna Reinelt, Viji Nair, Roman Akbar-Haase, Phillip J. McCown, Fabian Haas, He Chen, Mahdieh Rahmatollahi, Damian Fermin, Robin Ebbestad, Gisela G. Slaats, Tillmann Bork, Christoph Schell, Sybille Koehler, Paul T. Brinkkoetter, Maja T. Lindenmeyer, Clemens D. Cohen, Martin Kann, David Unnersjö-Jess, Wilhelm Bloch, Matthew G. Sampson, Martijn E.T. Dollé, Victor G. Puelles, Matthias Kretzler, George A. Garinis, Tobias B. Huber, Bernhard Schermer, Thomas Benzing, Björn Schumacher, Christine E. Kurschat

Air pollution and Alzheimer disease phenotype deplete esterified pro-resolving lipid mediator reserves in the brain

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Abstract

Background: Traffic-related air pollution (TRAP) is a risk factor for Alzheimer disease (AD), where unresolved brain inflammation has been linked to deficits in the levels of free lipid mediators that enable the resolution of inflammation. It is unknown whether these deficits are due to reductions in esterified lipid pools, the main source of free bioactive pro-resolving lipids in the brain, and whether they are related AD pathophysiology. Methods: This unknown was tested by measuring brain esterified lipid mediators and pathogenic markers of AD in TgF344-AD and wildtype (WT) male and female rats exposed to filtered air or TRAP for 14 months, and in human postmortem pre-frontal cortex of individuals with or without AD. Results: Significant reductions in pro-resolving lipid mediators esterified to neutral lipids and/or phospholipids were seen in AD and TRAP-exposed female rats, where levels were associated with inflammation, synaptic loss and impaired glucose metabolism. Lower esterified pro-resolving lipid mediator concentrations were associated with older age in pre-frontal cortex of humans with AD. Conclusion: Impaired resolution in AD is due to depletion of esterified pro-resolving lipid pools that supply the brain with free bioactive mediators involved in inflammation resolution. TRAP exposure alters the same esterified resolution pathways, reflecting convergent mechanisms underlying AD.

Authors

Ameer Y. Taha, Qing Shen, Yurika Otoki, Nuanyi Liang, Kelley T. Patten, Anthony E. Valenzuela, Christopher D. Wallis, Douglas J. Rowland, Abhijit J. Chaudhari, Keith J. Bein, Anthony S. Wexler, Lee-Way Jin, Brittany N. Dugger, Danielle J. Harvey, Pamela J. Lein

PAI-1 Interaction with Sortilin Related Receptor-1 is Required for Lung Fibrosis

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Abstract

Mutation studies of plasminogen activator inhibitor-1 (PAI-1) have previously implied that PAI-1 promotes lung fibrosis via a vitronectin (VTN) dependent mechanism. In the present study, employing two distinct murine fibrosis models and VTN deficient mice, we find that VTN is not required for PAI-1 to drive lung scarring. This result suggested the existence of a profibrotic interaction involving the VTN-binding site on PAI-1 with an unidentified ligand. Using an unbiased proteomic approach, we identified sortilin related receptor 1 (SorLA) as the most highly enriched PAI-1 binding partner in the fibrosing lung. Investigating the role of SorLA in pulmonary fibrosis demonstrated that deficiency of this protein protected against lung scarring in a murine model. We further found that SorLA is required for PAI-1 to promote scarring in mice, that both SorLA and PAI-1 protein levels are increased in human IPF explants, and that these proteins are associated in IPF tissue. Finally, confocal microscopy shows that expression of SorLA in CHO cells increases cell uptake of PAI-1, and these proteins colocalize in the cytoplasm. Together, these data elucidate a mechanism by which the potent profibrotic mediator PAI-1 drives lung fibrosis and implicate SorLA as a potential therapeutic target in IPF treatment.

Authors

Thomas H. Sisson, John J. Osterholzer, Lisa Leung, Venkatesha Basrur, Alexey I. Nesvizhskii, Natalya Subbotina, Mark Warnock, Daniel Torrente, Ammara Q. Virk, Sergey S. Gutor, Jeffrey C. Horowitz, Mary Migliorini, Dudley K. Strickland, Kevin K. Kim, Steven K. Huang, Daniel A. Lawrence

ICOS⁺CD4 T cells define a high susceptibility to anti-PD-1 therapy-induced lung pathogenesis

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Abstract

Managing immune-related adverse events (irAEs) caused by cancer immunotherapy is essential for developing effective and safer therapies. However, cellular mechanism(s) underlying organ toxicity during anti-PD-(L)1 therapy remain unclear. Here, we investigated the effect of chronological aging on anti-PD-(L)1 therapy-induced irAE-like lung toxicity, utilizing tumor-bearing aged mice. Anti-PD-(L)1 therapy facilitated ectopic infiltration of T and B cells, and antibody deposition in lung of aged but not young mice. Adoptive transfer of aged lung-derived CD4 T cells into TCR-deficient mice revealed that both pathogenic CD4 T cells and aged host environment were necessary for the irAE-inducible responses. Single-cell transcriptomics of lung-infiltrating cells in aged mice demonstrated that anti-PD-(L)1 therapy elicited ICOS+CD4 T-cell activation. Disruption of ICOS-ICOSL interaction attenuated germinal center B-cell differentiation and subsequent lung damage, which were overcome by local administration of IL-21 in the lung of anti-PD-1 therapy-treated aged mice. Therefore, ICOS+CD4 T cells elicited under aged environment exacerbated aberrant immune responses and the subsequent lung dysfunction. Consistent with the findings from mouse model, ICOS up-regulation in CD4 T cells was associated with later irAE incidence in patients with cancer. These finding will help development of useful strategies for irAE management in cancer patients, many of whom are elderly.

Authors

Mari Yokoi, Kosaku Murakami, Tomonori Yaguchi, Kenji Chamoto, Hiroaki Ozasa, Hironori Yoshida, Mirei Shirakashi, Katsuhiro Ito, Yoshihiro Komohara, Yukio Fujiwara, Hiromu Yano, Tatsuya Ogimoto, Daiki Hira, Tomohiro Terada, Toyohiro Hirai, Hirotake Tsukamoto