Autophagy promotes directed migration of HUVEC in response to electric fields through the ROS/SIRT1/FOXO1 pathway

SIRT3 mitigates dry eye disease through the activation of autophagy by deacetylation of FOXO1

Dry eye disease (DED) is a complex ocular condition characterized by oxidative stress, inflammation, and apoptosis. An increasing number of studies suggest that Sirtuin3 (SIRT3), a mitochondrial deacetylase, may offer protection against related pathologies. Despite these indications, the precise function and underlying mechanisms of SIRT3 in the context of DED have not been fully elucidated. Here, we observed a decline in SIRT3 expression in human corneal epithelial cells (HCE-Ts) and the corneal conjunctiva of mice as the disease advanced. Overexpression of SIRT3 in HCE-Ts reduced the accumulation of reactive oxygen species (ROS), inflammatory cytokines, and the rate of apoptosis, while its inhibition had the opposite effect. Importantly, the function of SIRT3 was exerted through the enhancement of autophagic flux. Further studies have shown that chloroquine-induced inhibition of autophagy neutralized the beneficial effects of SIRT3. In our in vivo experiments, the application of eye drops containing a SIRT3 agonist ameliorated the symptoms of DED and increased corneal autophagy in mice. Mechanistically, our study identified that the deacetylation and nuclear translocation of FOXO1 (Forkhead box O1) are pivotal for the SIRT3-mediated enhancement of autophagic flux. These findings posit that SIRT3 as an encouraging therapeutic target for DED, offering new insights into the disease's underlying mechanisms.

Liraglutide attenuates high glucose-induced endothelial cell senescence and dysfunction via SIRT1-mediated deacetylation of p53/p65

Endothelial aging is a critical pathogenic factor in various cardiovascular and metabolic disorders. Liraglutide (LIR), a glucagon-like peptide-1 receptor (GLP-1R) agonist used clinically to treat diabetes, controls blood sugar levels, and alleviates vascular stress, thereby protecting blood vessels. However, the mechanism by which it improves vascular aging remains to be elucidated. In this study, human umbilical vein endothelial cells were subjected to 30 mM glucose induction, followed by the addition of 1 μM LIR for 72 h. The findings indicated that LIR mitigated high glucose-induced endothelial cell senescence and downregulated the expression of markers linked to senescence, reactive oxygen species (ROS), and oxidative stress (p < 0.05). Additionally, it upregulated the expression of antioxidant markers and promoted angiogenesis and migration (p < 0.05). Western blot analysis of protein changes revealed that the therapeutic effects of LIR depend on SIRT1 and the acetylation of p53 and p65. Through SIRT1 overexpression and knockdown, we determined that SIRT1 regulates the acetylation of p53 and p65. Notably, the absence of SIRT1 diminished the therapeutic effects of LIR, whereas its overexpression enhanced these effects. Our findings suggest that high-glucose-induced endothelial cell aging and dysfunction may be involved in the pathogenesis of diabetic cardiovascular diseases (CVD). LIR treatment of high-glucose-induced vascular aging relies on the SIRT1-p53/p65 signaling axis. This study elucidates the mechanisms by which LIR ameliorates vascular aging and proposes a novel approach to mitigate vascular aging in elderly patients with diabetes.

Co-inhibition of RAGE and TLR4 sensitizes pancreatic cancer to irreversible electroporation in mice by disrupting autophagy

Irreversible electroporation (IRE) is a local ablative treatment for patients with pancreatic cancer. During the IRE procedure, high-intensity electric pulses are released intratumorally to disrupt plasma membranes and induce cell death. Since the intensity of the pulsed electric field (PEF) can be decreased by the tumor microenvironment, some cancer cells are subjected to a sublethal PEF and may survive to cause tumor recurrence later. Autophagy activation induced by anticancer therapies is known to promote treatment resistance. In this study, we investigated whether autophagy is activated in residual cancer cells after IRE and assessed the roles it plays during tumor recurrence. Subcutaneous KPC-A548 or Panc02 murine pancreatic cancer cell line xenograft mouse models were established; once the tumors reached 7 mm in one dimension, the tumor-bearing mice were subjected to IRE. For in vitro sublethal PEF treatment, the pancreatic cancer cell suspension was in direct contact with the electrodes and pulsed at room temperature. We showed that autophagy was activated in surviving residual cells, as evidenced by increased expression of LC3 and p62. Suppression of autophagy with hydroxychloroquine (60 mg/kg, daily intraperitoneal injection) markedly increased the efficacy of IRE. We demonstrated that autophagy activation can be attributed to increased expression of high-mobility group box 1 (HMGB1); co-inhibition of two HMGB1 receptors, receptor for advanced glycosylation end products (RAGE) and Toll-like receptor 4 (TLR4), suppressed autophagy activation by upregulating the PI3K/AKT/p70 ribosomal S6 protein kinase (p70S6K) axis and sensitized pancreatic cancer cells to PEF. We prepared a polymeric micelle formulation (M-R/T) encapsulating inhibitors of both RAGE and TLR4. The combination of IRE and M-R/T (equivalent to RAGE inhibitor at 10.4 mg/kg and TLR4 inhibitor at 5.7 mg/kg, intravenous or intraperitoneal injection every other day) significantly promoted tumor apoptosis, suppressed cell cycle progression, and prolonged animal survival in pancreatic tumor models. This study suggests that disruption of HMGB1-mediated autophagy with nanomedicine is a promising strategy to enhance the response of pancreatic cancer to IRE.

Exploring the therapeutic potential of Chinese herbs on comorbid type 2 diabetes mellitus and Parkinson's disease: A mechanistic study

ETHNOPHARMACOLOGICAL RELEVANCE

Type 2 diabetes mellitus (T2DM) and Parkinson's disease (PD) are chronic conditions that affect the aging population, with increasing prevalence globally. The rising prevalence of comorbidity between these conditions, driven by demographic shifts, severely impacts the quality of life of patients, posing a significant burden on healthcare resources. Chinese herbal medicine has been used to treat T2DM and PD for millennia. Pharmacological studies have demonstrated that medicinal herbs effectively lower blood glucose levels and exert neuroprotective effects, suggesting their potential as adjunctive therapy for concurrent management of T2DM and PD.

AIM OF THE STUDY

To elucidate the shared mechanisms underlying T2DM and PD, particularly focusing on the potential mechanisms by which medicinal herbs (including herbal formulas, single herbs, and active compounds) may treat these diseases, to provide valuable insights for developing therapeutics targeting comorbid T2DM and PD.

MATERIALS AND METHODS

Studies exploring the mechanisms underlying T2DM and PD, as well as the treatment of these conditions with medicinal herbs, were extracted from several electronic databases, including PubMed, Web of Science, Google Scholar, and China National Knowledge Infrastructure (CNKI).

RESULTS

Numerous studies have shown that inflammation, oxidative stress, insulin resistance, impaired autophagy, gut microbiota dysbiosis, and ferroptosis are shared mechanisms underlying T2DM and PD mediated through the NLRP3 inflammasome, NF-κB, MAPK, Keap1/Nrf2/ARE, PI3K/AKT, AMPK/SIRT1, and System XC--GSH-GPX4 signaling pathways. Thirty-four medicinal herbs, including 2 herbal formulas, 4 single herbs, and 28 active compounds, have been reported to potentially exert anti-T2DM and anti-PD effects by targeting these shared mechanisms.

CONCLUSIONS

Traditional Chinese medicine effectively combats T2DM and PD through shared pathological mechanisms, highlighting their potential for application in treating these comorbid conditions.

SIRT1 activation promotes bone repair by enhancing the coupling of type H vessel formation and osteogenesis

Bone repair is intricately correlated with vascular regeneration, especially of type H vessels. Sirtuin 1 (SIRT1) expression is closely associated with endothelial function and vascular regeneration; however, the role of SIRT1 in enhancing the coupling of type H vessel formation with osteogenesis to promote bone repair needs to be investigated. A co-culture system combining human umbilical vein endothelial cells and osteoblasts was constructed, and a SIRT1 agonist was used to evaluate the effects of SIRT1 activity. The angiogenic and osteogenic capacities of the co-culture system were examined using short interfering RNA. Mouse models with bone defects in the femur or mandible were established to explore changes in type H vessel formation and bone repair following modulated SIRT1 activity. SIRT1 activation augmented the angiogenic and osteogenic capacities of the co-culture system by activating the PI3K/AKT/FOXO1 signalling pathway and did not significantly regulate osteoblast differentiation. Inhibition of the PI3K/AKT/FOXO1 pathway attenuated SIRT1-mediated effects. The SIRT1 activity in bone defects was positively correlated with the formation of type H vessels and bone repair in vivo, whereas SIRT1 inhibition substantially weakened vascular and bone formation. Thus, SIRT1 is crucial to the coupling of type H vessels with osteogenesis during bone repair.

SIRT1: Harnessing multiple pathways to hinder NAFLD

Non-alcoholic fatty liver disease (NAFLD) encompasses hepatic steatosis, non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma. It is the primary cause of chronic liver disorders, with a high prevalence but no approved treatment. Therefore, it is indispensable to find a trustworthy therapy for NAFLD. Recently, mounting evidence illustrates that Sirtuin 1 (SIRT1) is strongly associated with NAFLD. SIRT1 activation or overexpression attenuate NAFLD, while SIRT1 deficiency aggravates NAFLD. Besides, an array of therapeutic agents, including natural compounds, synthetic compounds, traditional Chinese medicine formula, and stem cell transplantation, alleviates NALFD via SIRT1 activation or upregulation. Mechanically, SIRT1 alleviates NAFLD by reestablishing autophagy, enhancing mitochondrial function, suppressing oxidative stress, and coordinating lipid metabolism, as well as reducing hepatocyte apoptosis and inflammation. In this review, we introduced the structure and function of SIRT1 briefly, and summarized the effect of SIRT1 on NAFLD and its mechanism, along with the application of SIRT1 agonists in treating NAFLD.

Lipid peroxidation products' role in autophagy regulation

Autophagy, which is responsible for removing damaged molecules, prevents their accumulation in cells, thus maintaining intracellular homeostasis. It is also responsible for removing the effects of oxidative stress, so its activation takes place during increased reactive oxygen species (ROS) generation and lipid peroxidation. Therefore, the aim of this review was to summarize all the available knowledge about the effect of protein modifications by lipid peroxidation products on autophagy activation and the impact of this interaction on the functioning of cells. This review shows that reactive aldehydes (including 4-hydroxynonenal and malondialdehyde), either directly or by the formation of adducts with autophagic proteins, can activate or prevent autophagy, depending on their concentration. This effect relates not only to the initial stages of autophagy, when 4-hydroxynonenal and malondialdehyde affect the levels of proteins involved in autophagy initiation and phagophore formation, but also to the final stage, degradation, when reactive aldehydes, by binding to the active center of cathepsins, inactivate their proteolytic functions. Moreover, this review also shows how little research exists on analyzing the impact of lipid peroxidation products and their protein adducts on autophagy. Such knowledge could be used in the therapy of diseases related to autophagy disorders.

A review of the evidence to support electrical stimulation-induced vascularization in engineered tissue

Tissue engineering presents a promising solution for regenerative medicine and the success depends on the supply of oxygen/nutrients to the cells by rapid vascularization. More and more technologies are being developed to facilitate vascularization of engineered tissues. In this review, we indicated that a regulatory system which influences all angiogenesis associated cells to achieve their desired functional state is ideal for the construction of vascularized engineered tissues in vitro. We presented the evidence that electrical stimulation (ES) enhances the synergistic promotion of co-cultured angiogenesis associated cells and its potential regulatory mechanisms, highlighted the potential advantages of a combination of mesenchymal stem cells (MSCs), endothelial cells (ECs) and ES to achieve tissue vascularization, with particular emphasis on the different biological pathways of ES-regulated ECs. Finally, we proposed the future direction of using ES to reconstruct engineered tissue blood vessels, pointed out the potential advantages and disadvantages of ES application on tissue vascularization.

New Dawn for Atherosclerosis: Vascular Endothelial Cell Senescence and Death

Endothelial cells (ECs) form the inner linings of blood vessels, and are directly exposed to endogenous hazard signals and metabolites in the circulatory system. The senescence and death of ECs are not only adverse outcomes, but also causal contributors to endothelial dysfunction, an early risk marker of atherosclerosis. The pathophysiological process of EC senescence involves both structural and functional changes and has been linked to various factors, including oxidative stress, dysregulated cell cycle, hyperuricemia, vascular inflammation, and aberrant metabolite sensing and signaling. Multiple forms of EC death have been documented in atherosclerosis, including autophagic cell death, apoptosis, pyroptosis, NETosis, necroptosis, and ferroptosis. Despite this, the molecular mechanisms underlying EC senescence or death in atherogenesis are not fully understood. To provide a comprehensive update on the subject, this review examines the historic and latest findings on the molecular mechanisms and functional alterations associated with EC senescence and death in different stages of atherosclerosis.