SPATA4 improves aging-induced metabolic dysfunction through promotion of preadipocyte differentiation and adipose tissue expansion

Long noncoding RNA AI504432 upregulates FASN expression by sponging miR-1a-3p to promote lipogenesis in senescent adipocytes

Aging affects lipid metabolism and can cause obesity as it is closely related to the disorder of many lipogenic regulatory factors. LncRNAs have been recognized as pivotal regulators across diverse biological processes, but their effects on lipogenesis in aging remain to be further studied. In this work, using RNA sequencing (RNA-Seq), we found that the expression of lncRNA AI504432 was significantly upregulated in the eWAT (epididymal white adipose tissue) of aging mice, and the knockdown of AI504432 notably reduced the expression of several adipogenic genes (e.g., Cebp/α, Srebp-1c, Fasn, Acaca, and Scd1) in senescent adipocytes. The bioinformatics investigation revealed that AI504432 possessed a binding site for miR-1a-3p, and the discovery was verified by the luciferase reporter assay. The expression of Fasn was increased upon the inhibition of miR-1a-3p but restored upon the simultaneous silencing of AI504432. Taken together, our results suggested that AI504432 controlled lipogenesis through the miR-1a-3p/Fasn signaling pathway. The findings may inspire new therapeutic approaches to target imbalanced lipid homeostasis due to aging.

Aging and homeostasis of the hypodermis in the age-related deterioration of skin function

Adipose tissues in the hypodermis, the crucial stem cell reservoir in the skin and the endocrine organ for the maintenance of skin homeostasis undergo significant changes during skin aging. Dermal white adipose tissue (dWAT) has recently been recognized as an important organ for both non-metabolic and metabolic health in skin regeneration and rejuvenation. Defective differentiation, adipogenesis, improper adipocytokine production, and immunological dissonance dysfunction in dWAT lead to age-associated clinical changes. Here, we review age-related alterations in dWAT across levels, emphasizing the mechanisms underlying the regulation of aging. We also discuss the pathogenic changes involved in age-related fat dysfunction and the unfavorable consequences of accelerated skin aging, such as chronic inflammaging, immunosenescence, delayed wound healing, and fibrosis. Research has shown that adipose aging is an early initiation event and a potential target for extending longevity. We believe that adipose tissues play an essential role in aging and form a potential therapeutic target for the treatment of age-related skin diseases. Further research is needed to improve our understanding of this phenomenon.

Adipose tissue as a linchpin of organismal ageing

Ageing is a conserved biological process, modulated by intrinsic and extrinsic factors, that leads to changes in life expectancy. In humans, ageing is characterized by greatly increased prevalence of cardiometabolic disease, type 2 diabetes and disorders associated with impaired immune surveillance. Adipose tissue displays species-conserved, temporal changes with ageing, including redistribution from peripheral to central depots, loss of thermogenic capacity and expansion within the bone marrow. Adipose tissue is localized to discrete depots, and also diffusely distributed within multiple organs and tissues in direct proximity to specialized cells. Thus, through their potent endocrine properties, adipocytes are capable of modulating tissue and organ function throughout the body. In addition to adipocytes, multipotent progenitor/stem cells in adipose tissue play a crucial role in maintenance and repair of tissues throughout the lifetime. Adipose tissue may therefore be a central driver for organismal ageing and age-associated diseases. Here we review the features of adipose tissue during ageing, and discuss potential mechanisms by which these changes affect whole-body metabolism, immunity and longevity. We also explore the potential of adipose tissue-targeted therapies to ameliorate age-associated disease burdens.

Klotho Upregulation via PPARγ Contributes to the Induction of Brain Ischemic Tolerance by Cerebral Ischemic Preconditioning in Rats

Cerebral ischemic preconditioning (CIP)-induced brain ischemic tolerance protects neurons from subsequent lethal ischemic insult. However, the specific mechanisms underlying CIP remain unclear. In the present study, we explored the hypothesis that peroxisome proliferator-activated receptor gamma (PPARγ) participates in the upregulation of Klotho during the induction of brain ischemic tolerance by CIP. First we investigated the expression of Klotho during the brain ischemic tolerance induced by CIP. Lethal ischemia significantly decreased Klotho expression from 6 h to 7 days, while CIP significantly increased Klotho expression from 12 h to 7 days in the hippocampal CA1 region. Inhibition of Klotho expression by its shRNA blocked the neuroprotection induced by CIP. These results indicate that Klotho participates in brain ischemic tolerance by CIP. Furthermore, we tested the role of PPARγ in regulating Klotho expression after CIP. CIP caused PPARγ protein translocation to the nucleus in neurons in the CA1 region of the hippocampus. Pretreatment with GW9962, a PPARγ inhibitor, significantly attenuated the upregulation of Klotho protein and blocked the brain ischemic tolerance induced by CIP. Taken together, it can be concluded that Klotho upregulation via PPARγ contributes to the induction of brain ischemic tolerance by CIP.

New insight into dyslipidemia‐induced cellular senescence in atherosclerosis

Atherosclerosis, characterized by lipid‐rich plaques in the arterial wall, is an age‐related disorder and a leading cause of mortality worldwide. However, the specific mechanisms remain complex. Recently, emerging evidence has demonstrated that senescence of various types of cells, such as endothelial cells (ECs), vascular smooth muscle cells (VSMCs), macrophages, endothelial progenitor cells (EPCs), and adipose‐derived mesenchymal stem cells (AMSCs) contributes to atherosclerosis. Cellular senescence and atherosclerosis share various causative stimuli, in which dyslipidemia has attracted much attention. Dyslipidemia, mainly referred to elevated plasma levels of atherogenic lipids or lipoproteins, or functional impairment of anti‐atherogenic lipids or lipoproteins, plays a pivotal role both in cellular senescence and atherosclerosis. In this review, we summarize the current evidence for dyslipidemia‐induced cellular senescence during atherosclerosis, with a focus on low‐density lipoprotein (LDL) and its modifications, hydrolysate of triglyceride‐rich lipoproteins (TRLs), and high‐density lipoprotein (HDL), respectively. Furthermore, we describe the underlying mechanisms linking dyslipidemia‐induced cellular senescence and atherosclerosis. Finally, we discuss the senescence‐related therapeutic strategies for atherosclerosis, with special attention given to the anti‐atherosclerotic effects of promising geroprotectors as well as anti‐senescence effects of current lipid‐lowering drugs.

RNA-seq analysis of phagocytic cells from murine epididymal white adipose tissue shows immunosenescence and age-related phosphorus metabolism

The underlying state of alterations in adipose tissue is hypothesized to be as a result of age-related changes. Young and aged mice have been documented to show distinct gene expression and distinct macrophage-specific adipose tissue regulation. However, more biological understanding is required to know the processes associated with these conditions in relation to the aging process. Transcriptional profiling with RNA-seq analysis was used to determine differentially expressed genes in young (2 months old) and aged (20 months old) mice macrophage-enriched phagocytic stromal vascular fractions of pooled epididymal white adipose tissue using data obtained from gene expression omnibus. Results showed distinct differentially expressed genes in young and aged mice with a p value cutoff of 0.05 and dissimilarities in the young and aged epididymal white adipose tissue phagocytic cells. Functional enrichment showed activation of cytokine-cytokine receptor interaction pathways, phosphorus metabolic processes and inflammatory pathways such as IL-17, TNF, NF-kappa B, and TGF-β, while AMPK, PPAR and oxidative phosphorylation were suppressed. The analysis showed that aging is linked with phagocytic cell decline, accumulated cellular damages, inflammation, immunosenescence and increased phosphorus metabolism. Interventions that reduce phosphate-containing compound could improve phosphorus metabolism in old age to prolong lifespan and better health.