Targeting Cell Senescence and Senolytics: Novel Interventions for Age-Related Endocrine Dysfunction

Preconditioning and post-preconditioning states of mesenchymal stem cells with deferoxamine: A Comprehensive Analysis

Mesenchymal stem cells (MSCs) derive their therapeutic potential from their secretomes, which can be modulated by external stimuli. Hypoxia is one such stimulus, and research on preconditioning MSCs with hypoxia-mimetic agents is rising. However, the effects of these preconditioning processes and the resulting metabolic status require further investigation. This study evaluated the effects of deferoxamine (DFX), a hypoxia-mimetic agent, preconditioning on MSCs in serum and serum-free environments. The influence of hypoxia on cell metabolism was examined during and after preconditioning by assessing cytotoxicity, proliferation, migration, secretomes, senescence, autophagy, and apoptosis mechanisms. The optimal DFX dose and duration for preconditioning were determined as 150 μM and 24 hours based on cytotoxicity testing. Accordingly, DFX preconditioning significantly upregulated HIF-1α expression, increasing protein secretion and reducing total oxidant status. DFX appears to enhance the therapeutic potential of MSCs by increasing their secretome and antioxidant capacity. However, upon DFX removal, HIF-1α levels returned to normal, and the associated positive effects diminished. Autophagy was markedly enhanced during DFX preconditioning, potentially improving metabolic activity, preserving cellular integrity, and preparing MSCs for ischemic environments. Autophagy returned to baseline after DFX withdrawal, indicating a temporary hypoxia-mimetic response. In a serum-containing medium, specific effects of preconditioning were relatively weak to be observed. This study demonstrates that DFX-preconditioning increases MSCs' metabolic activity and enhances their adaptive cellular response. However, the effect may be transient, which provides insights into the behavior of MSCs in ischemic environments and emphasizes the need to evaluate the long-term effects of hypoxia-mimetic agents.

Aging: A struggle for beneficial to overcome negative factors made by muscle and bone

Musculoskeletal health is strongly influenced by regulatory interactions of bone and muscle. Recent discoveries have identified a number of key mechanisms through which soluble factors released during exercise by bone exert positive effects on muscle and by muscle on bone. Although exercise can delay the negative effects of aging, these beneficial effects are diminished with aging. The limited response of aged muscle and bone tissue to exercise are accompanied by a failure in bone and muscle communication. Here, we propose that exercise induced beneficial factors must battle changes in circulating endocrine and inflammatory factors that occur with aging. Furthermore, sedentary behavior results in the release of negative factors impacting the ability of bone and muscle to respond to physical activity especially with aging. In this review we report on exercise responsive factors and evidence of modification occurring with aging.

Combination of dasatinib and quercetin promotes osteogenic differentiation and stemness maintenance of hPDLSCs via YAP/TAZ

Human periodontal ligament stem cells (hPDLSCs) are candidate seed cells for periodontal tissue regeneration. Enhancing the stemness maintenance and osteogenic differentiation potential of hPDLSCs is conducive to their role in periodontal tissue regeneration. The combination of dasatinib and quercetin, a type of senolytic, has been reported to affect cell senescence. However, whether it can regulate the osteogenic differentiation and stemness maintenance of hPDLSCs, and the related mechanisms, remain unknown. The present study analyzed the optimal concentrations of dasatinib and quercetin in combination for hPDLSCs and found that the combination of dasatinib and quercetin enhanced osteogenic differentiation and promoted the expression of stemness-related markers in hPDLSCs. The expression levels of TAZ and YAP were improved when hPDLSCs were incubated with dasatinib and quercetin. However, the osteogenesis-promoting effects of dasatinib plus quercetin were partly attenuated when TAZ was knocked down, and their effects on stemness-related markers were suppressed when YAP was inhibited. Taken together, the combination of dasatinib and quercetin promotes the osteogenic differentiation and stemness maintenance of hPDLSCs, and YAP/TAZ may be involved in this process. This combination may hold promise for improving hPDLSCs function in periodontal tissue regeneration.

Targeting senescent cells for the treatment of age-associated diseases

Cellular senescence, which entails cellular dysfunction and inflammatory factor release-the senescence-associated secretory phenotype (SASP)-is a key contributor to multiple disorders, diseases and the geriatric syndromes. Targeting senescent cells using senolytics has emerged as a promising therapeutic strategy for these conditions. Among senolytics, the combination of dasatinib and quercetin (D + Q) was the earliest and one of the most successful so far. D + Q delays, prevents, alleviates or treats multiple senescence-associated diseases and disorders with improvements in healthspan across various pre-clinical models. While early senolytic therapies have demonstrated promise, ongoing research is crucial to refine them and address such challenges as off-target effects. Recent advances in senolytics include new drugs and therapies that target senescent cells more effectively. The identification of senescence-associated antigens-cell surface molecules on senescent cells-pointed to another promising means for developing novel therapies and identifying biomarkers of senescent cell abundance.

Rejuvenation of Bone Marrow Mesenchymal Stem Cells: Mechanisms and Their Application in Senile Osteoporosis Treatment

Bone marrow mesenchymal stromal cells (BM-MSCs) are multipotent cells present in bone marrow; they play a crucial role in the process of bone formation. Cellular senescence is defined as a stable state of cell cycle arrest that impairs the functioning of cells. Research has shown that aging triggers a state of senescence in BM-MSCs, leading to a reduced capacity for osteogenic differentiation and the accumulation of senescent cells, which can accelerate the onset of various diseases. Therefore, it is essential to explore mechanisms and strategies for the rejuvenation of senescent BM-MSCs. Senile osteoporosis (SOP) is a metabolic bone disease characterized by reduced bone formation. The senescence of BM-MSCs is considered one of the most important factors in the occurrence and development of SOP. Therefore, the rejuvenation of BM-MSCs for the treatment of SOP represents a promising strategy. This work provides a summary of the functional alterations observed in senescent BM-MSCs and a systematic review of the mechanisms that facilitate the rejuvenation of senescent BM-MSCs. Additionally, we analyze the progress in and the limitations associated with the application of rejuvenated senescent BM-MSCs to treat SOP, with the aim of providing new insights for the prevention and treatment of SOP.

Cellular senescence: from homeostasis to pathological implications and therapeutic strategies

Cellular aging is a multifactorial and intricately regulated physiological process with profound implications. The interaction between cellular senescence and cancer is complex and multifaceted, senescence can both promote and inhibit tumor progression through various mechanisms. M6A methylation modification regulates the aging process of cells and tissues by modulating senescence-related genes. In this review, we comprehensively discuss the characteristics of cellular senescence, the signaling pathways regulating senescence, the biomarkers of senescence, and the mechanisms of anti-senescence drugs. Notably, this review also delves into the complex interactions between senescence and cancer, emphasizing the dual role of the senescent microenvironment in tumor initiation, progression, and treatment. Finally, we thoroughly explore the function and mechanism of m6A methylation modification in cellular senescence, revealing its critical role in regulating gene expression and maintaining cellular homeostasis. In conclusion, this review provides a comprehensive perspective on the molecular mechanisms and biological significance of cellular senescence and offers new insights for the development of anti-senescence strategies.

Association Between Allometric Body Shape Indices and Osteoporosis in Postmenopausal Women: A Cross-Sectional Study from NHANES

Background

Osteoporosis is a common health concern in postmenopausal women. Obesity, commonly assessed using body mass index (BMI), may have a protective effect on osteoporosis in postmenopausal women. As BMI is limited to the distinguishing fat accumulation, the study aimed to explore the association between allometric body shape indices [including a body shape index (ABSI), hip index, (HI), and waist-hip index (WHI)] and osteoporosis in postmenopausal women.

Methods

Postmenopausal women aged >50 years in the National Health and Nutrition Examination Survey from 2017 through 2020 (revised to 01/2017 through 12/2020) were included. Potential covariates were selected using the univariate logistic regression models. The association between allometric body shape indices and osteoporosis was explored using weighted univariate and multivariate logistic regression models, with results presented as odds ratios (ORs) and 95% confidence intervals (CIs). The association was further explored in different age and BMI populations. Area under the curve (AUC) analysis was conducted to evaluate the predictive performance of WHI.

Results

In total, 810 postmenopausal women aged >50 years were included. Among them, 597 (73.70%) women have osteoporosis. WHI ≥0.094 (OR = 2.07, 95% CI: 1.14-3.78) was associated with higher odds of osteoporosis in postmenopausal women. BMI ≥30 kg/m2 (OR = 0.23, 95% CI: 0.11-0.50) was also related to decreased odds of osteoporosis. ABSI ≥85.74 was related to a higher incidence of osteoporosis in women aged ≥70 years (OR = 4.18, 95% CI: 1.22-14.35) and BMI ≥30 kg/m2 (OR = 4.25, 95% CI: 1.82-9.95). The WHI has a better predictive performance with an AUC of 0.656 (95% CI: 0.613-0.699) than the waist-hip ratio.

Conclusion

Higher WHI was associated with an increased incidence of osteoporosis in postmenopausal women. Higher ABSI was related to a higher incidence of osteoporosis in women aged ≥70 years and those with a BMI ≥30 kg/m2. WHI could predict the incidence of osteoporosis in postmenopausal women.

Aberrant STING activation promotes macrophage senescence by suppressing autophagy in vascular aging from diabetes

Diabetic vascular aging is driven by macrophage senescence, which propagates senescence-associated secretory phenotypes (SASP), exacerbating vascular dysfunction. This study utilized a type 2 diabetes mellitus (T2DM) mouse model induced by streptozotocin injection and a high-fat diet to investigate the role of STING in macrophage senescence. Vascular aging markers and senescent macrophages were assessed in vivo, while in vitro, high glucose treatment induced macrophage senescence, enhancing senescence in co-cultured vascular smooth muscle cells. Mechanistic studies revealed that STING activation inhibits autophagy by phosphorylating ULK1 at S757, accelerating senescence. Pharmacological modulation showed that the STING inhibitor H-151 alleviates, while the agonist DMXAA enhances, senescence. These findings highlight the STING-autophagy axis as a critical driver of macrophage senescence, offering insights into the molecular mechanisms of diabetic vascular aging and identifying potential therapeutic targets to mitigate vascular complications in diabetes.

AQP1 mediates pancreatic β cell senescence induced by metabolic stress through modulating intracellular H2O2 level

Metabolic stress-induced pancreatic β cell senescence plays a pivotal role in the type 2 diabetes progression, and yet the precise molecular mechanisms remain elusive. Through cellular experiments and bioinformatics analyses, we identified aquaporin 1(AQP1)-mediated transmembrane transport of hydrogen peroxide as a key driver of glucolipotoxicity-induced senescence in MIN6 cells. A PPI network analysis was used to cross-reference 17 differentially expressed genes associated with type 2 diabetes from three independent GEO databases with 188 stress-induced senescence-related genes from CellAge. AQP1 was revealed as a critical molecular nexus connecting diabetes, oxidative stress, and cellular senescence. AQP1 inhibition, through Bacopaside II and si-AQP1, significantly reduced critical senescence markers in MIN6 cells, demonstrated by the reversal of glucolipotoxicity-induced upregulation of p16, p21, and p-γH2A.X, activation of the senescence-associated secretory phenotype genes, and an elevated percentage of senescence-associated-β-galactosidase positive cells. These effects were primarily mediated through oxidative stress MAPK signaling pathway modulation. AQP1 inhibition is crucial in alleviating glucolipotoxicity-induced β cell senescence. It underscores its potential as a molecular target for therapeutic strategies to delay pancreatic β cell senescence by modulating antioxidant pathways during metabolic stress.

Immune senescence: A key player in cancer biology

With the rapid development of immunological techniques in recent years, our understanding of immune senescence has gradually deepened, but the role of immune senescence in cancer biology remains incompletely elucidated. Understanding these mechanisms and interactions is crucial for the development of tumor biology. This review examines five key areas: the classification and main features of immune senescence, factors influencing immune cell senescence in cancer, the reciprocal causal cycle between immune senescence and malignancy, and the potential of immune senescence as a target for cancer immunotherapy.

Association between visceral adiposity index, lipid accumulation product and type 2 diabetes mellitus in US adults with hypertension: a cross-sectional analysis of NHANES from 2005 to 2018

BACKGROUND

The presence of hypertension significantly increases the risk of diabetes, particularly type 2 diabetes. Recently, Visceral Adiposity Index (VAI) has been introduced as a straightforward and robust alternative indicator for early detection of metabolic syndrome, cardiovascular disease, and T2DM. Visceral adiposity, more dangerous than subcutaneous fat, is associated with metabolic syndrome and cardiovascular diseases. The VAI and Lipid Accumulation Product (LAP) are indices that quantify visceral fat and lipid overaccumulation, respectively. This study aims to explore the association between VAI, LAP, and type 2 diabetes mellitus (T2DM) in US adults with hypertension using NHANES data from 2005 to 2018.

METHODS

We analyzed data from 5,620 participants with hypertension in The National Health and Nutrition Examination Survey (NHANES). VAI and LAP were calculated using established formulas. The VAI is calculated based on a combination of waist circumference, body mass index (BMI), triglycerides, and high-density lipoprotein (HDL) cholesterol levels. Logistic regression models were applied to evaluate the association between these indices and T2DM, adjusting for potential confounders. Subgroup analyses by age and gender were also conducted to assess variations in risk.

RESULTS

In all, 5,620 participants were enrolled in our analysis, with 2,754 (49%) being female, and a mean (standard deviation, SD) age of 57 (15) years. The mean (SD) cumulative average VAI and LAP among all participants was 241 (2.71) and 75 (67), respectively. Totally, higher VAI and LAP indices were significantly associated with an increased risk of T2DM in individuals with hypertension. For VAI, the odds ratios (OR) for T2DM were higher in older adults (≥ 60 years) [95% confidence interval (CI): 1.37, 1.22-1.53, per 1 SD increase] and females [95% confidence interval (CI): 1.39, 1.27-1.52, per 1 SD increase], indicating age and gender differences in risk. Non-linear relationships were observed, suggesting thresholds beyond which the risk of T2DM escalates dramatically.

CONCLUSIONS

Both VAI and LAP are reliable markers for assessing T2DM risk in individuals with hypertension. Incorporating these indices into clinical practice could enhance the identification of high-risk individuals and facilitate early intervention strategies. Future longitudinal studies are needed to confirm these associations and explore targeted interventions.