Berberine-mediated REDD1 down-regulation ameliorates senescence of retinal pigment epithelium by interrupting the ROS-DDR positive feedback loop

REDD1 knockdown ameliorates endothelial cell senescence through repressing TXNIP-mediated oxidative stress

Endothelial cell senescence characterized by reactive oxygen species (ROS) accumulation and chronic inflammation is widely recognized as a key contributor to atherosclerosis (AS). Regulated in development and DNA damage response 1 (REDD1), a conserved stress-response protein that regulates ROS production, is involved in the pathogenesis of various age-related diseases. However, the role of REDD1 in endothelial cell senescence is still unclear. Here, we screened REDD1 as a differentially expressed senescence-related gene in the AS progression using bioinformatics methods, and validated the upregulation of REDD1 expression in AS plaques, senescent endothelial cells, and aging aorta by constructing AS mice, D-galactose (DG)-induced senescent endothelial cells and DG-induced accelerated aging mice, respectively. siRNA against REDD1 could improve DG-induced premature senescence of endothelial cells and inhibit ROS accumulation, similar to antioxidant N-Acetylcysteine (NAC) treatment. Meanwhile, NAC reduced the upregulation of REDD1 induced by DG, supporting the positive feedback loop between REDD1 and ROS contributes to endothelial cell senescence. Mechanistically, the regulatory effect of REDD1 on ROS might be related to the TXNIP-REDD1 interaction in DG-induced endothelial cell senescence. Collectively, experiments above provide evidence that REDD1 participates in endothelial cell senescence through repressing TXNIP-mediated oxidative stress, which may be involved in the progression of atherosclerosis.

SEPHS1 attenuates intervertebral disc degeneration by delaying nucleus pulposus cell senescence through the Hippo-Yap/Taz pathway

Nucleus pulposus cell (NPC) senescence is a major cause of intervertebral disc degeneration (IVDD). Oxidative stress and reactive oxygen species (ROS) play critical roles in regulating cell senescence. Selenophosphate synthetase 1 (SEPHS1) was reported to play an important role in mitigating oxidative stress in an osteoarthritis (OA) model by reducing the production of ROS, thereby, delaying the occurrence and development of osteoarthritis. In this study, we explored the, hitherto unknown, role of SEPHS1 in IVDD in vitro and in vivo using an interleukin-1β (IL-1β)-induced NPC senescence model and a rat needle puncture IVDD model, respectively. SEPHS1 delayed NPC senescence in vitro by reducing ROS production. Age-related dysfunction was also ameliorated by the overexpression of SEPHS1 and inhibition of the Hippo-Yap/Taz signaling pathway. In vivo experiments revealed that the overexpression of SEPHS1 and inhibition of Hippo-Yap/Taz alleviated IVDD in rats. Moreover, a selenium (Se)-deficient diet and lack of SEPHS1 synergistically aggravated IVDD progression. Taken together, our results demonstrate that SEPHS1 plays a significant role in NPC senescence. Overexpression of SEPHS1 and inhibition of Hippo-Yap/Taz can delay NPC senescence, restore the balance of extracellular matrix metabolism, and attenuate IVDD. SEPHS1 could be a promising therapeutic target for IVDD.NEW & NOTEWORTHY Selenophosphate synthetase 1 (SEPHS1) deficiency leads to an increase in reactive oxygen species levels and in the subsequent activation of the Hippo-Yap/Taz signaling pathway. In the rat model of intervertebral disc degeneration (IVDD), overexpression of SEPHS1 and inhibition of Hippo-YAP/Taz mitigated the progression of disc degeneration indicating the involvement of SEPHS1 in IVDD. SEPHS1 is a promising therapeutic target for IVDD.

Molecular Network Mechanism Analysis of Urine Stem Cells Against Retinal Aging

To investigate the effect and potential mechanism of human-derived urine stem cells (hUSCs) in inhibiting retinal aging by using experimental and bioinformatics. Retinal pigment epithelial cells cultured in vitro, which were randomly divided into normal group, aging group and supernatant of hUSCs group. Cell counting kit-8 detection, senescence-related β-galactosidase, and Annexin V/PI staining were performed to detect cell viability, senescence, and apoptosis. Subsequently, bioinformatics methods were used to explore the underlying mechanisms, in which, targets both hUSCs and aging retina-related targets were obtained from GeneCards. Then, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, and protein-protein interaction network were analysis, and the expressional level of hub gene was validated by q-PCR. Supernatant addition of hUSCs promoted markedly cellular proliferation, improved viability and inhibited senescence and apoptosis in vitro. A total of 1476 hUSCs-related targets (Relevance score > 20), 692 retinal disease-related targets, and 732 targets related to disease of aging were selected from GeneCards database, and 289 common targets of hUSCs against aging retina were confirmed through Venn analysis. Enrichment analysis demonstrated that hUSCs might exert its anti-apoptosis efficacy in multiple biological processes, including oxidative stress, inflammation and apoptosis, and core targets were associated with HIF-1, MAPK and PI3K-Akt signal. hUSCs inhibited retinal senescence by regulating multiply targets and signaling pathways, of these, HIF-1, MAPK, and PI3K may be important candidates.

Aerobic exercise mitigates hippocampal neuronal apoptosis by regulating DAPK1/CDKN2A/REDD1/FoXO1/FasL signaling pathway in D-galactose-induced aging mice

Brain aging is the most important risk factor for neurodegenerative disorders, and abnormal apoptosis is linked to neuronal dysfunction. Specifically, studies have found that exercise effectively inhibits hippocampal neuronal apoptosis, while the molecular mechanism remains unclear. In the present study, we investigated the impact of aerobic exercise on hippocampal neuronal apoptosis in aging mice and the potential involvement of DAPK1 and its downstream pathways based on recent data that DAPK1 may be associated with neuronal death in neurodegenerative diseases. Senescent mice were subjected to 8 weeks of Aerobic training. Following behavioral testing, hippocampal samples were examined histologically and biochemically to detect pathological changes, neuronal apoptosis, and mRNA and protein levels. We found that the exercise intervention improved spatial memory and alleviated neuronal apoptosis in the brain. Notably, exercise down-regulated DAPK1 expression and inhibited Fas death receptor transactivation and the mitochondrial apoptotic pathway in the hippocampus. These results shed new light on the protective effect of regular exercise against brain aging though modulating the DAPK1 pathway.

Calcium/P53/Ninjurin 1 Signaling Mediates Plasma Membrane Rupture of Acinar Cells in Severe Acute Pancreatitis

Ninjurin 1 (NINJ1) is a double-transmembrane cell-surface protein that might mediate plasma membrane rupture (PMR) and the diffusion of inflammatory factors. PMR is a characteristic of acinar cell injury in severe acute pancreatitis (SAP). However, the involvement of NINJ1 in mediating the PMR of acinar cells in SAP is currently unclear. Our study has shown that NINJ1 is expressed in acinar cells, and the expression is significantly upregulated in sodium-taurocholate-induced SAP. The knockout of NINJ1 delays PMR in acinar cells and alleviates SAP. Moreover, we observed that NINJ1 expression is mediated by Ca2+ concentration in acinar cells. Importantly, we found that Ca2+ overload drives mitochondrial stress to upregulate the P53/NINJ1 pathway, inducing PMR in acinar cells, and amlodipine, a Ca2+ channel inhibitor, can reduce the occurrence of PMR by decreasing the concentration of Ca2+. Our results demonstrate the mechanism by which NINJ1 induces PMR in SAP acinar cells and provide a potential new target for treatment of SAP.

Antiaging effects of dietary supplements and natural products

Aging is an inevitable process influenced by genetics, lifestyles, and environments. With the rapid social and economic development in recent decades, the proportion of the elderly has increased rapidly worldwide, and many aging-related diseases have shown an upward trend, including nervous system diseases, cardiovascular diseases, metabolic diseases, and cancer. The rising burden of aging-related diseases has become an urgent global health challenge and requires immediate attention and solutions. Natural products have been used for a long time to treat various human diseases. The primary cellular pathways that mediate the longevity-extending effects of natural products involve nutrient-sensing pathways. Among them, the sirtuin, AMP-activated protein kinase, mammalian target of rapamycin, p53, and insulin/insulin-like growth factor-1 signaling pathways are most widely studied. Several studies have reviewed the effects of individual natural compounds on aging and aging-related diseases along with the underlying mechanisms. Natural products from food sources, such as polyphenols, saponins, alkaloids, and polysaccharides, are classified as antiaging compounds that promote health and prolong life via various mechanisms. In this article, we have reviewed several recently identified natural products with potential antiaging properties and have highlighted their cellular and molecular mechanisms. The discovery and use of dietary supplements and natural products that can prevent and treat multiple aging-related diseases in humans will be beneficial. Thus, this review provides theoretical background for existing dietary supplements and natural products as potential antiaging agents.

NIPSNAP1 directs dual mechanisms to restrain senescence in cancer cells

BACKGROUND

Although the executive pathways of senescence are known, the underlying control mechanisms are diverse and not fully understood, particularly how cancer cells avoid triggering senescence despite experiencing exacerbated stress conditions within the tumor microenvironment.

METHODS

Mass spectrometry (MS)-based proteomic screening was used to identify differentially regulated genes in serum-starved hepatocellular carcinoma cells and RNAi employed to determine knockdown phenotypes of prioritized genes. Thereafter, gene function was investigated using cell proliferation assays (colony-formation, CCK-8, Edu incorporation and cell cycle) together with cellular senescence assays (SA-β-gal, SAHF and SASP). Gene overexpression and knockdown techniques were applied to examine mRNA and protein regulation in combination with luciferase reporter and proteasome degradation assays, respectively. Flow cytometry was applied to detect changes in cellular reactive oxygen species (ROS) and in vivo gene function examined using a xenograft model.

RESULTS

Among the genes induced by serum deprivation, NIPSNAP1 was selected for investigation. Subsequent experiments revealed that NIPSNAP1 promotes cancer cell proliferation and inhibits P27-dependent induction of senescence via dual mechanisms. Firstly, NIPSNAP1 maintains the levels of c-Myc by sequestering the E3 ubiquitin ligase FBXL14 to prevent the proteasome-mediated turnover of c-Myc. Intriguingly, NIPSNAP1 levels are restrained by transcriptional repression mediated by c-Myc-Miz1, with repression lifted in response to serum withdrawal, thus identifying feedback regulation between NIPSNAP1 and c-Myc. Secondly, NIPSNAP1 was shown to modulate ROS levels by promoting interactions between the deacetylase SIRT3 and superoxide dismutase 2 (SOD2). Consequent activation of SOD2 serves to maintain cellular ROS levels below the critical levels required to induce cell cycle arrest and senescence. Importantly, the actions of NIPSNAP1 in promoting cancer cell proliferation and preventing senescence were recapitulated in vivo using xenograft models.

CONCLUSIONS

Together, these findings reveal NIPSNAP1 as an important mediator of c-Myc function and a negative regulator of cellular senescence. These findings also provide a theoretical basis for cancer therapy where targeting NIPSNAP1 invokes cellular senescence.