The Emerging Role of Sestrin2 in Cell Metabolism, and Cardiovascular and Age-Related Diseases

The emerging role of exercise in Alzheimer's disease: Focus on mitochondrial function

Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by memory impairment and cognitive dysfunction, which eventually leads to the disability and mortality of older adults. Although the precise mechanisms by which age promotes the development of AD remains poorly understood, mitochondrial dysfunction plays a central role in the development of AD. Currently, there is no effective treatment for this debilitating disease. It is well accepted that exercise exerts neuroprotective effects by ameliorating mitochondrial dysfunction in the neurons of AD, which involves multiple mechanisms, including mitochondrial dynamics, biogenesis, mitophagy, transport, and signal transduction. In addition, exercise promotes mitochondria communication with other organelles in AD neurons, which should receive more attentions in the future.

Sestrin2 in POMC neurons modulates energy balance and obesity related metabolic disorders via mTOR signaling

Sestrin2 is a highly conserved protein that can be induced under various stress conditions. Researches have revealed that the signaling pathway of the mammalian target of rapamycin (mTOR) is essential in modulating both glucose and lipid metabolism. However, the precise involvement of Sestrin2 in the hypothalamus, particularly in pro-opiomelanocortin (POMC) neurons, in control of energy homeostasis remains uncertain. In this study, we aimed to investigate the functional role of Sestrin2 in hypothalamic POMC neurons in regulation of energy balance, as well as revealing the underlying mechanisms. Therefore, cre-dependent AAV virus encoding or silencing Sestrin2 was injected into the hypothalamic ARC of pomc-cre transgenic mice. The results demonstrated that Sestrin2 overexpression in POMC neurons ameliorated high-fat diet (HFD)-induced obesity and increased energy expenditure. Conversely, Sestrin2 deficiency in POMC neurons predisposed mice to HFD induced obesity. Additionally, the thermogenesis of brown adipose tissue and lipolysis of inguinal white adipose tissue were both enhanced by the increased sympathetic nerve innervation in Sestrin2 overexpressed mice. Further exploration revealed that Sestrin2 overexpression inhibited the mTOR signaling pathway in hypothalamic POMC neurons, which may account for the alleviation of systematic metabolic disturbance induced by HFD in these mice. Collectively, our findings demonstrate that Sestrin2 in POMC neurons plays a pivotal role in maintaining energy balance in a context of HFD-induced obesity by inhibiting the mTOR pathway, providing new insights into how hypothalamic neurons respond to nutritional signals to protect against obesity-associated metabolic dysfunction.

The effects of whole-body vibration therapy on immune and brain functioning: current insights in the underlying cellular and molecular mechanisms

Whole-body vibration (WBV) therapy is a way of passive exercise in which subjects are exposed to mild and well-controlled mechanical vibrations through a vibrating platform. For a long time, studies have focused on the effects and applications of WBV to enhance musculoskeletal performance in athletes and patients suffering from musculoskeletal disorders. Recent evidence points toward the positive effect of WBV on the brain and its therapeutic potential in brain disorders. Research being done in the field gradually reveals cellular and molecular mechanisms underlying WBV affecting the body and brain. Particularly, the influence of WBV on immune and brain function is a growing field that warrants an up-to-date and integrated review. Immune function is closely intertwined with brain functioning and plays a significant role in various brain disorders. Dysregulation of the immune response is linked to conditions such as neuroinflammation, neurodegenerative diseases, and mood disorders, highlighting the crucial connection between the immune system and the brain. This review aims to explore the impact of WBV on the cellular and molecular pathways involved in immune and brain functions. Understanding the effects of WBV at a cellular and molecular level will aid in optimizing WBV protocols to improve its therapeutic potential for brain disorders.

Evaluation of serum levels of sestrin 2 and betatrophin in type 2 diabetic patients with diabetic nephropathy

BACKGROUND

Diabetic kidney disease (DKD) is one of the most serious microvascular complications of diabetes mellitus (DM) and the leading cause of chronic kidney disease (CKD) worldwide. Since obesity and type 2 DM (T2DM) are considered as inflammatory conditions, thus reducing their accompanied systemic inflammation may lessen their complications. Sestrin 2 belongs to a group of stress induced proteins which are produced in response to oxidative stress, inflammation and DNA damage. Betatrophin; a hormone that stimulates the growth, proliferation and mass expansion of pancreatic beta-cells and improves glucose tolerance. The objective of the study was to evaluate levels of serum Sestrin 2 and betatrophin in patients with different stages of diabetic nephropathy (DN)) and compare results with healthy control.

METHODS

This cross sectional study was carried out on 60 patients above 18 years old, recruited from Tanta University hospitals out patients clinics and 20 apparently healthy individuals of matched sex and age as a control group. Participants were divided into two groups: group I: 20 normal subjects as control group and group II: 60 patients with type 2 DM,. further subdivided in to three equal groups: group 1IIA(20 patients) with normo-albuminuria (ACR < 30 mg/g), group IIB (20 patients) with micro albuminuria (ACR = 30 to 300 mg/g) and group IIC (20 patients) with macro albuminuria (ACR > 300 mg/g). They were subjected to detailed history taking, careful clinical examination and laboratory investigations including blood urea, serum creatinine, estimated glomerular filtration rate (eGFR), urinary albumin creatinine ratio, and specific laboratory tests for Sestrin 2 and Betatrophin by using ELISA technique.

RESULTS

Serum Sestrin 2 significantly decreased, while serum betatrophin level significantly increased in macroalbuminuric group compared to control and other 2 diabetic groups (P value < 0.05). The cut off value of serum sestrin 2 was 0.98 ng/ml with sensitivity 99%, specificity 66% while the cut off value of serum betatrophin was > 98.25 ng/ml with sensitivity 98%, specificity 82%. Serum betatrophin positively correlated with age, fasting, 2 h postprandial, BMI, triglyceride, total cholesterol, serum creatinine, blood urea, UACR, and negatively correlated with eGFR and serum albumin. Serum Sestrin 2 positively correlated with serum albumin. BMI, serum urea, UACR and serum albumin. Serum betatrophin are found to be risk factors or predictors for diabetic nephropathy.

CONCLUSIONS

Patients with DN, particularly the macroalbuminuria group, had a significant increase in betatrophin levels and a significant decrease in serum Sestrin 2 level. The function of Sestrin 2 is compromised in DN, and restoring it can reverse a series of molecular alterations with subsequent improvement of the renal functions, albuminuria and structural damage.

Allicin regulates Sestrin2 ubiquitination to affect macrophage autophagy and senescence, thus inhibiting the growth of hepatoma cells

BACKGROUND

Allicin regulates macrophage autophagy and senescence, and inhibits hepatoma cell growth. This study investigated the mechanism by which allicin inhibits the growth of hepatoma cells.

METHODS

Hepa1-6 mouse hepatoma cells were subcutaneously injected into C57BL/6 J mice to construct a tumor transplantation model. Macrophages were cultured with the supernatant of hepatoma cells to construct a cell model. The levels of mRNA and proteins and the level of Sestrin2 ubiquitination were measured by RTqPCR, immunofluorescence and Western blotting. The levels of autophagy-related factors and the activity of senescence-associated β-galactosidase were determined by kits, and protein stability was detected by cycloheximide (CHX) tracking.

RESULTS

Data analysis of clinical samples revealed that RBX1 was highly expressed in tumor tissues, while Sestrin2 was expressed at low levels in tumor tissues. Allicin can promote the expression of the autophagy-related proteins LC3 and Beclin-1 in tumor macrophages and inhibit the expression of the aging-related proteins p16 and p21, thus promoting autophagy in macrophages and inhibiting cell senescence. Moreover, allicin can inhibit the expression of RBX1, thereby reducing the ubiquitination of Sestrin2, enhancing the stability of Sestrin2, activating autophagy in tumor macrophages and inhibiting senescence. In addition, allicin treatment inhibited the proliferation and migration of hepatoma carcinoma cells cocultured with macrophages and significantly improved the development of liver cancer in mice.

CONCLUSION

Allicin can affect the autophagy of macrophages and restrain the growth of hepatoma cells by regulating the ubiquitination of Sestrin2.

Association of Free Radical Product and Polycystic Ovary Syndrome: A Systematic Review and Meta-analysis

PURPOSE

Polycystic ovary syndrome (PCOS) is an endocrine disorder that primarily affects women of reproductive age. It is recognized as the leading cause of infertility due to anovulation. This research aims to evaluate the diagnostic potential of oxidative stress biomarkers, including advanced oxidation protein products (AOPP), malondialdehyde (MDA), uric acid (UA), and nitric oxide (NO), in identifying PCOS.

METHODS

A literature search was conducted in the EMBASE, PubMed, Cochrane Library, and Scopus databases. The standardized mean difference (SMD) and 95% confidence interval (CI) were employed to assess the correlation between free radical product and PCOS. Moreover, the presence of heterogeneity among the studies was assessed utilizing the I2 statistic and Cochran Q test. The methodological rigor of the incorporated studies was assessed through the application of the Newcastle-Ottawa Scale. Furthermore, the presence of publication bias was determined via Begg and Egger tests.

RESULTS

This meta-analysis reviewed 38 observational studies, including 17,845 women. The results revealed a significant association between PCOS in women and alterations in free radical levels. The study revealed that the PCOS group had significantly higher levels of AOPP (SMD = 3.193; 95% CI, 2.86 to 3.25), UA (SMD = 0.68; 95% CI, 0.24 to 1.13), and MDA (SMD = 1.16; 95% CI, 0.77 to 1.56) compared to the healthy control group. Furthermore, the analysis found a significantly lower level of NO (SMD = (- 0.59); 95% CI, - 1.15 to - 0.03) in the PCOS patient.

CONCLUSION

Screening of specific biomarkers associated with free radical products could provide valuable benefits in the prognosis and diagnosis of PCOS.

Metabolic pathways in immune senescence and inflammaging: Novel therapeutic strategy for chronic inflammatory lung diseases. An EAACI position paper from the Task Force for Immunopharmacology

The accumulation of senescent cells drives inflammaging and increases morbidity of chronic inflammatory lung diseases. Immune responses are built upon dynamic changes in cell metabolism that supply energy and substrates for cell proliferation, differentiation, and activation. Metabolic changes imposed by environmental stress and inflammation on immune cells and tissue microenvironment are thus chiefly involved in the pathophysiology of allergic and other immune-driven diseases. Altered cell metabolism is also a hallmark of cell senescence, a condition characterized by loss of proliferative activity in cells that remain metabolically active. Accelerated senescence can be triggered by acute or chronic stress and inflammatory responses. In contrast, replicative senescence occurs as part of the physiological aging process and has protective roles in cancer surveillance and wound healing. Importantly, cell senescence can also change or hamper response to diverse therapeutic treatments. Understanding the metabolic pathways of senescence in immune and structural cells is therefore critical to detect, prevent, or revert detrimental aspects of senescence-related immunopathology, by developing specific diagnostics and targeted therapies. In this paper, we review the main changes and metabolic alterations occurring in senescent immune cells (macrophages, B cells, T cells). Subsequently, we present the metabolic footprints described in translational studies in patients with chronic asthma and chronic obstructive pulmonary disease (COPD), and review the ongoing preclinical studies and clinical trials of therapeutic approaches aiming at targeting metabolic pathways to antagonize pathological senescence. Because this is a recently emerging field in allergy and clinical immunology, a better understanding of the metabolic profile of the complex landscape of cell senescence is needed. The progress achieved so far is already providing opportunities for new therapies, as well as for strategies aimed at disease prevention and supporting healthy aging.

Effect of resistance training plus enriched probiotic supplement on sestrin2, oxidative stress, and mitophagy markers in elderly male Wistar rats

This study aimed to determine the effects of resistance training combined with a probiotic supplement enriched with vitamin D and leucine on sestrin2, oxidative stress, antioxidant defense, and mitophagy markers in aged Wistar rats. Thirty-five male rats were randomly assigned to two age groups (old with 18-24 months of age and young with 8-12 weeks of age) and then divided into five groups, including (1) old control (OC: n = 5 + 2 for reserve in all groups), (2) young control (YC: n = 5), (3) old resistance training (OR: n = 5), (4) old resistance training plus supplement (ORS: n = 5), and old supplement group (OS: n = 5). Training groups performed ladder climbing resistance training 3 times per week for 8 weeks. Training intensity was inserted progressively, with values equal to 65, 75, and 85, determining rats' maximal carrying load capacity. Each animal made 5 to 8 climbs in each training session, and the time of each climb was between 12 and 15 s, although the time was not the subject of the evaluation, and the climbing pattern was different in the animals. Old resistance plus supplement and old supplement groups received 1 ml of supplement 5 times per week by oral gavage in addition to standard feeding, 1 to 2 h post training sessions. Forty-eight hours after the end of the training program, 3 ml of blood samples were taken, and all rats were then sacrificed to achieve muscle samples. After 8 weeks of training, total antioxidant capacity and superoxide dismutase activity levels increased in both interventions. A synergistic effect of supplement with resistance training was observed for total antioxidant capacity, superoxide dismutase, and PTEN-induced kinase 1. Sestrin 2 decreased in intervention groups. These results suggest that resistance training plus supplement can boost antioxidant defense and mitophagy while potentially decreasing muscle strength loss.

MicroRNA-29a and microRNA-122 expressions and other inflammatory markers among obese children with diabetes

OBJECTIVES

This study was conducted to study the expression of both microRNA-29a and microRNA-122, and serum levels of sestrin-2, interleukin-6 (IL-6), and other inflammatory markers among obese children with/and without diabetes mellitus.

METHODS

One hundred obese children with diabetes in addition to 100 age- and sex-matched obese children without diabetes, and 100 age- and sex-matched apparently healthy children were included in the study. Expressions of both microRNA-29a and microRNA-122, and serum levels of sestrin-2, IL-6, tumor necrosis factor-α (TNF-α), and high sensitive-CRP (hsCRP) were measured for all included study populations.

RESULTS

Study results showed that the expressions of both microRNA-29a and microRNA-122, serum levels of IL-6, TNF-α, and hsCRP were significantly higher among obese children with diabetes in comparison to both obese children without diabetes and healthy children. In contrast, serum sestrin level was significantly low among obese children with diabetes in comparison to the other study populations. Expressions of both microRNA-29a and microRNA-122 were correlated with waist circumference, BMI, total cholesterol, triglycerides, LDL-cholesterol, HbA1c, c-peptide, glucose, insulin, homeostatic model assessment-insulin resistance (HOMA-IR), IL-6, hsCRP, and TNF-α among obese children with diabetes. However, serum sestrin-2 level was correlated inversely with these parameters. Higher expressions of both microRNA-29a and microRNA-122 among obese children either with or without diabetes mellitus (DM) can suggest their roles in the development of obesity among children.

CONCLUSIONS

The study results can hypothesize that down-regulation of these micro-RNAs may solve this health problem with its sequelae, a hypothesis that needs more studies.

Sestrin 2 protects human lens epithelial cells from oxidative stress and apoptosis induced by hydrogen peroxide by regulating the mTOR/Nrf2 pathway

OBJECTIVE

We aimed to explore the effect and potential mechanism of Sestrin 2 (SESN2) in human lens epithelial cells (HLECs).

METHODS

To mimic the oxidative stress environment, SAR01/04 cells were treated with 200 μM hydrogen peroxide (H2O2) for 24 h. Cell viability and apoptosis were checked by cell counting kit-8 and flow cytometry. Western blot was taken to check the protein changes of SESN2, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X (Bax), mechanistic target of rapamycin (mTOR), phosphorylated (p)-mTOR, ribosomal protein S6 kinase B1 (p70S6K), p-p70S6K, and nuclear factor erythroid 2-related factor 2 (Nrf2). Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and reactive oxygen species (ROS) were detected via the corresponding reagent kit. The levels of interleukin (IL)-1β, IL-18, and tumor necrosis factor (TNF)-α were measured using enzyme-linked immunosorbent assay.

RESULTS

SESN2 was down-regulated in cataract lens tissue and up-regulated in SAR01/04 cells treated with H2O2. Under treatment of H2O2, up-regulation of SESN2 improved cell viability, enhanced the activity of SOD and CAT, inhibited cell apoptosis, and reduced the levels of MDA, ROS, IL-1β, IL-18, and TNF-α, while down-regulation of SESN2 caused the contrary effects. Further bioinformatics analysis suggested that SESN2 regulated the mTOR signaling pathway. Treatment of H2O2 inhibited p-mTOR and p-p70S6K protein expression, while overexpression of SESN2 increased p-mTOR and p-p70S6K protein expression in the H2O2 group and down-regulation of SESN2 further decreased p-mTOR and p-p70S6K protein expression in the H2O2 group. Additionally, H2O2 increased Nrf2 protein expression, and overexpression of SESN2 further increased Nrf2 protein expression in the H2O2 group. Importantly, rapamycin (an inhibitor of mTOR signaling pathway) and knockdown of Nrf2 reversed the promotive effects of SESN2 on cell viability and the inhibitive effects of SESN2 on cell apoptosis, oxidative stress, and inflammatory reaction.

CONCLUSION

SESN2 protected HLECs damage induced by H2O2, which was related to the activation of mTOR/Nrf2 pathway.

MicroRNA-34a-5p promotes the progression of osteoarthritis secondary to developmental dysplasia of the hip by restraining SESN2-induced autophagy

Osteoarthritis (OA), a late-stage complication of developmental dysplasia of the hip (DDH), is a key factor leading to further degeneration of joint function. Studies have shown that Sestrin2 (SESN2) is a positive regulator in protecting articular cartilage from degradation. However, the regulatory effects of SESN2 on DDH-OA and its upstream regulators remain obscure. Here, we first identified that the expression of SESN2 significantly decreased in the cartilage of DDH-OA samples, with an expression trend negatively correlated with OA severity. Using RNA sequencing, we identified that the upregulation of miR-34a-5p may be an important factor for the decrease in SESN2 expression. Further exploring the regulation mechanism of miR-34a-5p/SESN2 is of great significance for understanding the mechanism of DDH occurrence and development. Mechanistically, we showed that miR-34a-5p could significantly inhibit the expression of SESN2, thereby promoting the activity of the mTOR signaling pathway. We also found that miR-34a-5p significantly inhibited SESN2-induced autophagy, thereby suppressing the proliferation and migration of chondrocytes. We further validated that knocking down miR-34a-5p in vivo resulted in a significant increase in SESN2 expression and autophagy activity in DDH-OA cartilage. Our study suggests that miR-34a-5p is a negative regulator of DDH-OA, and may provide a new target for the prevention of DDH-OA.

Resistance exercise alleviates the prefrontal lobe injury and dysfunction by activating SESN2/AMPK/PGC-1α signaling pathway and inhibiting oxidative stress and inflammation in mice with myocardial infarction

OBJECTIVES

Myocardial infarction (MI) induces inflammatory response and oxidative stress in the brain, which would be one of the causes of cardiac dysfunction. Exercise training is viewed as a feasible strategy to improve cardiac function of the infarcted heart. The aim of this study was to investigate whether exercise training could alleviate MI-induced prefrontal lobe injury via activating Sestrin2 (SESN2) signaling and inhibiting oxidative stress and inflammation.

METHODS

Male C57BL/6 mice were divided into five groups: control group (CON), aerobic exercise group (AE), resistance exercise group (RE), whole-body vibration group (WBV) and electrical stimulation group (ES); and three groups: sham-operated group (S), sedentary MI group (MI) and MI with resistance exercise group (MRE). After four weeks of training, sensorimotor function, spatial learning, long-term and spatial memory, and cardiac function were detected. Then, mice were euthanized, and the prefrontal areas were separated for HE, Nissl, SESN2, microtubule-associated protein 2 (MAP2), neuron-specific nucleoprotein (NeuN), and TUNEL staining. Activation of SESN2/adenosine monophosphate-activated protein kinase (AMPK)/peroxisome proliferator activated receptor γ coactivator-1α (PGC-1α) signaling pathway and expression of proteins related to oxidative stress, inflammation and apoptosis in the prefrontal lobe were detected by western blotting.

RESULTS

Different types of exercise training all activated the SESN2/AMPK/PGC-1α signaling pathway, and the effect of RE is the best. RE improved sensorimotor, learning, and memory impairments, increased the expressions of antioxidant, anti-inflammatory and anti-apoptotic proteins, reduced oxidative stress, inflammation and apoptosis, ultimately alleviated the prefrontal lobe injury and dysfunction in mice with MI.

CONCLUSION

RE alleviates MI-indued prefrontal lobe injury and dysfunction by inhibiting the levels of oxidative stress, inflammation and apoptosis, partially via activating SESN2/AMPK/PGC-1α signaling pathway.

Metformin Caused Radiosensitivity of Breast Cancer Cells through the Expression Modulation of miR-21-5p/SESN1axis

OBJECTIVE

In this research we evaluated molecular mechanism of effect of metformin in radio sensitivity of breast cancer cells.

METHODS

This research was done in cellular and molecular research center of Qazvin university of Medical science in 1399 to 1401. Studied samples were two breast cancer cell lines (MCF-7 and MDA-MB-231) they are derived from primary and secondary tumors resected from a single patient. We exposed them to cumulative 50 Gy radiation and constructed radio resistant cell lines. Then resistant cell lines were treated with 50µm of metformin. Our studied groups were resistant cells treated and un treated with metformin. Then, the expression rate of miR-21-5p and SESN1 gene in resistant and control cells was checked by Quantitative Real-time PCR(qRTPCR). After the cell lines were treated with different concentrations of metformin at different intervals, the rate of cell proliferation and cell death was checked by CCK-8 assay and flow cytometry. The Western blot method was also used to confirm the expression of some genes.

RESULTS

Our results showed that the expression of miR-21-5p was upregulated in radiation-resistant cancer cells (1.8±0.65) (P<0.0001) MCF-7 cell line and (1.6±0.42)(P<0.001) MBA-MD-231 cell line, while the expression of SESN1 was down regulated (0.46±0.12) (P<0.0001) MCF-7 cell line and (0.42±0.22) (P<0.001) MBA-MD-231 cell line. Metformin enhanced the radio sensitivity of breast cancer cells in a dose and time-dependent manner. Also, metformin treatment decreased the expression of miR-21-5p (0.47±0.32) (P<0.0001) MCF-7 Cell line and (0.45±0.21)(P<0.001) MBA-MD-231 cell line and increased the expression of SESN1 (1.65±0.72)(P<0.0001)MCF-7 cell line and (1.73±0.52)(P<0.0001) MBA-MD-231 cell line. The function of metformin was reversed by miR-21-5p inhibitors or the transfection of SESN1 overexpressing plasmids.

CONCLUSION

In conclusion, based on this research results, metformin enhanced the radio sensitivity of breast cancer cells via modulating  the expression of miR-21-5p and SESN1.

chi-miR-130b-3p regulates the ZEA-induced oxidative stress damage through the KEAP1/NRF2 signaling pathway by targeting SESN2 in goat GCs

As a dominant mycotoxin, zearalenone (ZEA) has attracted extensive attention due to its estrogen-like effect and oxidative stress damage in cells. In order to find a way to relieve cell oxidative stress damage caused by ZEA, we treated goat granulosa cells (GCs) with ZEA and did a whole transcriptome sequencing. The results showed that the expression level of Sesterin2 (SESN2) was promoted extremely significantly in the ZEA group (p < .01). In addition, our research demonstrated that SESN2 could regulate oxidative stress level in GCs through Recombinant Kelch Like ECH Associated Protein 1 (KEAP1)/Nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway. The overexpression of SESN2 could reduce the oxidative damage, whereas knockdown of SESN2 would aggravate the oxidative damage caused by ZEA. What's more, microRNA (miRNA) chi-miR-130b-3p can bind to SESN2 3'-untranslated region (3'UTR) to regulate the expression of SESN2. The mimics/inhibition of chi-miR-130b-3p would have an effect on oxidative damage triggered by ZEA in GCs as well. In summary, these results elucidate a new pathway by which chi-miR-130b-3p affects the KEAP1/NRF2 pathway in GCs by modulating SESN2 expression in response to ZEA-induced oxidative stress damage.

Disturbed hemodynamics and oxidative stress interaction in endothelial dysfunction and AAA progression: Focus on Nrf2 pathway

Hemodynamic shear stress is one of the major factors that are involved in the pathogenesis of many cardiovascular diseases including atherosclerosis and abdominal aortic aneurysm (AAA), through its modulatory effect on the endothelial cell's redox homeostasis and mechanosensitive gene expression. Among important mechanisms, oxidative stress, endoplasmic reticulum stress activation, and the subsequent endothelial dysfunction are attributed to disturbed blood flow and low shear stress in the vascular curvature and bifurcations which are considered atheroprone regions and aneurysm occurrence spots. Many pathways were shown to be involved in AAA progression. Of particular interest from recent findings is, the (Nrf2)/Keap-1 pathway, where Nrf2 is a transcription factor that has antioxidant properties and is strongly associated with several CVDs, yet, the exact mechanism by which Nrf2 alleviates CVDs still to be elucidated. Nrf2 expression is closely affected by shear stress and was shown to participate in AAA. In the current review paper, we discussed the link between disturbed hemodynamics and its effect on Nrf2 as a mechanosensitive gene and its role in the development of endothelial dysfunction which is linked to the progression of AAA.

An update on the bridging factors connecting autophagy and Nrf2 antioxidant pathway

Macroautophagy/autophagy is a lysosome-dependent catabolic pathway for the degradation of intracellular proteins and organelles. Autophagy dysfunction is related to many diseases, including lysosomal storage diseases, cancer, neurodegenerative diseases, cardiomyopathy, and chronic metabolic diseases, in which increased reactive oxygen species (ROS) levels are also observed. ROS can randomly oxidize proteins, lipids, and DNA, causing oxidative stress and damage. Cells have developed various antioxidant pathways to reduce excessive ROS and maintain redox homeostasis. Treatment targeting only one aspect of diseases with autophagy dysfunction and oxidative stress shows very limited effects. Herein, identifying the bridging factors that can regulate both autophagy and antioxidant pathways is beneficial for dual-target therapies. This review intends to provide insights into the current identified bridging factors that connect autophagy and Nrf2 antioxidant pathway, as well as their tight interconnection with each other. These factors could be potential dual-purpose targets for the treatment of diseases implicated in both autophagy dysfunction and oxidative stress.

Glycyrrhizic Acid Protects Glomerular Podocytes Induced by High Glucose by Modulating SNARK/AMPK Signaling Pathway

OBJECTIVE

Diabetic nephropathy is one of the most important microvascular complications of diabetes, which mainly refers to glomerular capillary sclerosis. Podocytes are an important part of glomerular capillaries. Previous clinical and basic studies have shown that fibrosis is the main factor of diabetic nephropathy. This study aimed to assess the protective mechanism of glycyrrhizic acid (GA) on glomerular podocytes induced by high glucose as we hypothesized that GA may have antifibrotic and anti-inflammatory effects on podocytes through regulation of the adenosine 5'-monophosphate-activated protein kinase (AMPK)/sucrose nonfermenting AMPK-related kinase (SNARK) signaling pathway.

METHODS

SNARK siRNA was used to transfect podocytes. Real-time quantitative polymerase chain reaction and immunofluorescence staining assays were used for molecular and pathological analysis. The expression levels of key pathway proteins (including TGF-β1, α-SMA, SITR1, AMPKα, LKB1, PGC-1α, NF-κB, IL-6, and TNF-α) were verified by Western blotting. The expression of inflammatory factors in podocytes was detected by ELISA.

RESULTS

We demonstrated that GA decreased the expression of podocyte fibrosis signaling pathway-related factors by upregulating the AMPK pathway and its related factors. However, after transfection of podocytes with SNARK siRNA, there was an increased expression of fibrosis-related factors and inflammation-related factors.

CONCLUSION

GA can protect podocytes and alleviate fibrosis and inflammation induced by high glucose, which is related to the AMPK signaling pathway. Meanwhile, knockdown of SNARK protein can inhibit the AMPK signaling pathway, aggravate fibrosis, and increase inflammation.

Atherosclerotic and Cardio-Metabolic Diseases: From Molecular Basis to Therapeutic Advances

Cardiovascular diseases (CVDs) still remain the major cause of death worldwide; however, CVD-related mortality has been reduced due to lifestyle modification interventions, as well as novel pharmacological therapies and advances in cardiovascular surgery [...].

Sestrin2-mediated disassembly of stress granules dampens aerobic glycolysis to overcome glucose starvation

Sestrins are a small gene family of pleiotropic factors whose actions promote cell adaptation to a range of stress conditions. In this report we disclose the selective role of Sestrin2 (SESN2) in dampening aerobic glycolysis to adapt to limiting glucose conditions. Removal of glucose from hepatocellular carcinoma (HCC) cells inhibits glycolysis associated with the downregulation of the rate-limiting glycolytic enzyme hexokinase 2 (HK2). Moreover, the accompanying upregulation of SESN2 through an NRF2/ATF4-dependent mechanism plays a direct role in HK2 regulation by destabilizing HK2 mRNA. We show SESN2 competes with insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3) for binding with the 3'-UTR region of HK2 mRNA. Interactions between IGF2BP3 and HK2 mRNA result in their coalescence into stress granules via liquid-liquid phase separation (LLPS), a process which serves to stabilize HK2 mRNA. Conversely, the enhanced expression and cytoplasmic localization of SESN2 under glucose deprivation conditions favors the downregulation of HK2 levels via decreases in the half-life of HK2 mRNA. The resulting dampening of glucose uptake and glycolytic flux inhibits cell proliferation and protect cells from glucose starvation-induced apoptotic cell death. Collectively, our findings reveal an intrinsic survival mechanism allowing cancer cells to overcome chronic glucose shortages, also providing new mechanistic insights into SESN2 as an RNA-binding protein with a role in reprogramming of cancer cell metabolism.

An update on the molecular mechanism and pharmacological interventions for Ischemia-reperfusion injury by regulating AMPK/mTOR signaling pathway in autophagy

AMP-activated protein kinase (5'-adenosine monophosphate-activated protein kinase, AMPK)/mammalian target of rapamycin (mTOR) is an important signaling pathway maintaining normal cell function and homeostasis in vivo. The AMPK/mTOR pathway regulates cellular proliferation, autophagy, and apoptosis. Ischemia-reperfusion injury (IRI) is secondary damage that frequently occurs clinically in various disease processes and treatments, and the exacerbated injury during tissue reperfusion increases disease-associated morbidity and mortality. IRI arises from multiple complex pathological mechanisms, among which cell autophagy is a focus of recent research and a new therapeutic target. The activation of AMPK/mTOR signaling in IRI can modulate cellular metabolism and regulate cell proliferation and immune cell differentiation by adjusting gene transcription and protein synthesis. Thus, the AMPK/mTOR signaling pathway has been intensively investigated in studies focused on IRI prevention and treatment. In recent years, AMPK/mTOR pathway-mediated autophagy has been found to play a crucial role in IRI treatment. This article aims to elaborate the action mechanisms of AMPK/mTOR signaling pathway activation in IRI and summarize the progress of AMPK/mTOR-mediated autophagy research in the field of IRI therapy.

Sestrin2 contributes to BRAF inhibitor resistance via reducing redox vulnerability of melanoma cells

BACKGROUND

Treatment resistance often occurs with BRAF inhibitor (BRAFi) therapy for melanoma, bringing in a great challenge to the treatment of melanoma patients harboring mutant BRAF gene. Recent studies revealed redox vulnerability constitutes a novel opportunity to overcome BRAFi resistance. Previously we found Sestrin2 provided protection to metastatic melanoma cells by detoxifying reactive oxygen species (ROS) induced by anoikis, but its defensive role against redox stimuli elicited by BRAFi was unclear.

OBJECTIVE

In-depth explored the role of Sestrin2 in BRAFi-resistant melanoma.

METHODS

Vemurafenib-resistant melanoma cells were established using 451Lu and UACC62 cell lines carrying BRAF^V600E mutation. Mechanistic studies were subsequently performed by transfection of lentiviral vectors encoding an shRNA against SESN2 or embedded with the coding sequences of SESN2 cDNA.

RESULTS

Elevated Sestrin2 expression was found in vemurafenib-resistance melanoma cells. Further mechanistic studies revealed that BRAFi-resistant melanoma cells employ Sestrin2 to adapt to higher oxidative stress under vemurafenib exposure. It was also demonstrated that mTOR signaling was significantly activated following Sestrin2 knockdown. Given the known promoting role of active mTOR signaling in melanoma proliferation and survival, the effects of mTOR blocker and Sestrin2 ablation on BRAFi-resistant melanoma cells were further tested, and the combination was found to result in enhanced inhibition of melanoma cell growth.

CONCLUSIONS

Our findings demonstrated the contribution of Sestrin2 to the development of BRAFi resistance and the fact that the combination of mTOR blocker assisted Sestrein2 ablation in eliminating BRAFi resistance of melanoma. Therefore, mTOR and Sestrin2 may be novel combinatorial therapeutic targets to overcome BRAFi resistance of melanoma.

Empagliflozin activates Sestrin2-mediated AMPK/mTOR pathway and ameliorates lipid accumulation in obesity-related nonalcoholic fatty liver disease

Empagliflozin (EMPA) therapy has led to improvements in patients with non-alcoholic fatty liver disease (NAFLD). Sestrin2 is a stress-inducible protein that controls the AMPK-mTOR pathway and inhibits oxidative damage in cells. This study investigated the functional implications of EMPA on the multifactorial pathogenesis of NAFLD and potential underlying molecular mechanisms of pathogenesis. An in vitro model of NAFLD was established by treating HepG2 cells with palmitic acid (PA); an in vivo model of NAFLD was generated by feeding C57BL/6 mice a high-fat diet. Investigations of morphology and lipid deposition in liver tissue were performed. Expression patterns of Sestrin2 and genes related to lipogenesis and inflammation were assessed by reverse transcription polymerase chain reaction. Protein levels of Sestrin2 and AMPK/mTOR pathway components were detected by Western blotting. NAFLD liver tissues and PA-stimulated HepG2 cells exhibited excessive lipid production and triglyceride secretion, along with upregulation of Sestrin2 and increased expression of lipogenesis-related genes. EMPA treatment reversed liver damage by upregulating Sestrin2 and activating the AMPK-mTOR pathway. Knockdown of Sestrin2 effectively increased lipogenesis and enhanced the mRNA expression levels of lipogenic and pro-inflammatory genes in PA-stimulated HepG2 cells; EMPA treatment did not affect these changes. Furthermore, Sestrin2 knockdown inhibited AMPK-mTOR signaling pathway activity. The upregulation of Sestrin2 after treatment with EMPA protects against lipid deposition-related metabolic disorders; it also inhibits lipogenesis and inflammation through activation of the AMPK-mTOR signaling pathway. These results suggest that Sestrin2 can be targeted by EMPA therapy to alleviate lipogenesis and inflammation in obesity-related NAFLD.

Targeting on Nrf2/Sesn2 Signaling to Rescue Cardiac Dysfunction during High-Fat Diet-Induced Obesity

Obesity is of concern to the population because it is known to cause inflammation and oxidative stress throughout the body, leading to patient predisposition for health conditions such as diabetes, hypertension, and some cancers. However, some proteins that are activated in times of oxidative stress may provide cytoprotective properties. In this study, we aim to gain further understanding of the interconnection between Nrf2 and Sesn2 during obesity-related stress and how this relationship can play a role in cardio-protection. Cardiomyocyte-specific Sesn2 knockout (cSesn2^-/-) and Sesn2 overexpressed (tTa-tet-Sesn2) mice and their wildtype littermates (Sesn2^flox/flox and tet-Sesn2, respectively) were assigned to either a normal chow (NC) or a high-fat (HF) diet to induce obesity. After 16 weeks of dietary intervention, heart function was evaluated via echocardiography and cardiac tissue was collected for analysis. Immunoblotting, histology, and ROS staining were completed. Human heart samples were obtained via the LifeLink Foundation and were also subjected to analysis. Overall, these results indicated that the overexpression of Sesn2 appears to have cardio-protective effects on the obese heart through the reduction of ROS and fibrosis present in the tissues and in cardiac function. These results were consistent for both mouse and human heart samples. In human samples, there was an increase in Sesn2 and Nrf2 expression in the obese patients' LV tissue. However, there was no observable pattern of Sesn2/Nrf2 expression in mouse LV tissue samples. Further investigation into the link between the Sesn2/Nrf2 pathway and obesity-related oxidative stress is needed.

ER stress induces myocardial dysfunction and cardiac autophagy in Sestrin2 knockout mice

OBJECTIVES

Sestrin2 is an essential regulator of the cellular adaptive response against various stresses. The endoplasmic reticulum (ER) is critical in maintaining normal cardiac function by controlling intracellular Ca²⁺ accumulation, as well as protein folding and processing. Autophagy contributes to stress-associated heart dysfunction. AMP-activated protein kinase (AMPK) is important in energy homeostasis in cardiomyocytes. However, the function of Sestrin2 (Sesn2) in ER stress-induced autophagy that induces myocardial dysfunction has not been clarified. In this study, mice and cardiac tissues were treated with tunicamycin (TN), an inducer of ER stress. We then explored the roles of Sesn2 and the AMPK pathway associated with autophagy in ER stress-induced myocardial dysfunction in mice.

METHODS

Echocardiography, contractile function analysis, intracellular Ca²⁺ status, and immunoblot analysis of AMPK pathway were performed, ER stress and autophagy markers were examined.

RESULTS

The study revealed that ER stress caused significant heart dysfunction and cardiotoxicity in the mouse heart and cardiomyocytes. Biochemical analysis indicated enhanced cardiac autophagy mediated by ER stress and AMPK/mTOR activation. Sesn2 knockout exacerbated ER stress-related myocardial dysfunction due to the failed response of cardiac autophagy and AMPK/mTOR pathway activation. Further, pharmacological inhibition of AMPK or autophagy worsened TN-induced cardiac dysfunction.

CONCLUSION

Taken together, loss of the Sesn2 protein exacerbates ER stress-induced cardiac dysfunction through the AMPK/mTOR signaling cascade and loss of autophagy response.

SESN1 attenuates the Ox‑LDL‑induced inflammation, apoptosis and endothelial‑mesenchymal transition of human umbilical vein endothelial cells by regulating AMPK/SIRT1/LOX1 signaling

Endothelial cells are an important component of the heart and vasculature and form a crucial link between the cardiovascular system and the immune system. Sestrin 1 (SESN1) has an important role in atherosclerosis by inhibiting NOD-like receptor family pyrin domain containing 3 inflammasome activation. However, whether SESN1 is involved in human umbilical vein endothelial cell (HUVEC) injury caused by atherosclerosis has remained to be elucidated. The present study aimed to investigate the functions of SESN1 in the inflammatory response, apoptosis and endothelial-mesenchymal transition (EndMT) of HUVECs following stimulation with oxidized low-density lipoprotein (Ox-LDL). SESN1 expression at the mRNA and protein levels was detected using reverse transcription-quantitative PCR (RT-qPCR) and western blot analysis. Following SESN1 overexpression in Ox-LDL-stimulated HUVECs, cell viability was determined using a Cell Counting Kit-8 assay. Terminal deoxynucleotidyl transferase-mediated nick-end labeling staining was employed to detect cell apoptosis and western blot analysis was used to determine the levels of apoptosis-related proteins. RT-qPCR, ELISA and western blot were utilized to determine the levels of inflammatory factors. Immunofluorescence staining, RT-qPCR and western blot analysis were employed to assess the EndMT of Ox-LDL-stimulated HUVECs. The results revealed that SESN1 exhibited a low expression in HUVECs following Ox-LDL stimulation. SESN1 overexpression suppressed inflammation, apoptosis and EndMT in Ox-LDL-induced HUVECs. In addition, SESN1 stimulated adenosine monophosphate-activated protein kinase catalytic subunit α1/sirtuin 1 signaling to suppress Ox-LDL receptor-1 expression. An AMPK and SIRT1 inhibitor reversed the effects of SESN1 overexpression on the inflammatory response, apoptosis and EndMT of HUVECs exposed to Ox-LDL. Taken together, the present study demonstrated that SENS1 exerts a suppressive effect on Ox-LDL-induced inflammation, apoptosis and EndMT of HUVECs, suggesting that SENS1 may be used as a novel biomarker for endothelial injury-related disorders.

Inhibition of Sestrin2 overexpression in diabetic cardiomyopathy ameliorates cardiac injury via restoration of mitochondrial function

Mitochondrial dysfunction-induced apoptosis plays a crucial role in the progression of diabetic cardiomyopathy (DCM). Sestrin2 is an important oxidative stress response protein and is involved in the maintenance of mitochondrial function, especially under stress. The aim of the present study was to investigate the role of Sestrin2 in DCM and to explore the underlying mechanisms. H9c2 cardiomyocytes were induced with high glucose (HG) medium (33 mmol/l glucose) for an in vitro DCM model. C57BL/6 mice were induced for the in vivo DCM model by intraperitoneal streptozotocin injection. H9c2 cardiomyocytes were exposed to HG and infected with lentiviruses to express Sestrin2 short hairpin RNA (shRNA). The study found that cell viability and mitochondrial function were impaired while cell apoptosis and oxidative stress were increased in DCM. Sestrin2 was significantly upregulated in myocardial tissues of DCM mice and H9c2 cardiomyocytes in HG conditions. Downregulation of Sestrin2 increased cell viability, decreased cell apoptosis, and attenuated oxidative stress in H9c2 cells exposed to HG. Moreover, HG-induced mitochondrial injury was alleviated by Sestrin2 silencing. In conclusion, our finding indicated that the inhibition of enhanced Sestrin2 expression ameliorates cardiac injury in DCM, which might be largely attributed to the restoration of mitochondrial function.

The functions and roles of sestrins in regulating human diseases

Sestrins (Sesns), highly conserved stress-inducible metabolic proteins, are known to protect organisms against various noxious stimuli including DNA damage, oxidative stress, starvation, endoplasmic reticulum (ER) stress, and hypoxia. Sesns regulate metabolism mainly through activation of the key energy sensor AMP-dependent protein kinase (AMPK) and inhibition of mammalian target of rapamycin complex 1 (mTORC1). Sesns also play pivotal roles in autophagy activation and apoptosis inhibition in normal cells, while conversely promoting apoptosis in cancer cells. The functions of Sesns in diseases such as metabolic disorders, neurodegenerative diseases, cardiovascular diseases, and cancer have been broadly investigated in the past decades. However, there is a limited number of reviews that have summarized the functions of Sesns in the pathophysiological processes of human diseases, especially musculoskeletal system diseases. One aim of this review is to discuss the biological functions of Sesns in the pathophysiological process and phenotype of diseases. More significantly, we include some new evidence about the musculoskeletal system. Another purpose is to explore whether Sesns could be potential biomarkers or targets in the future diagnostic and therapeutic process.

Prolactin and Its Altered Action in Alzheimer's Disease and Parkinson's Disease

BACKGROUND

Prolactin (PRL) is one of the most diverse pituitary hormones and is known to modulate normal neuronal function and neurodegenerative conditions. Many studies have described the influence that PRL has on the central nervous system and addressed its contribution to neurodegeneration, but little is known about the mechanisms responsible for the effects of PRL on neurodegenerative disorders, especially on Alzheimer's disease (AD) and Parkinson's disease (PD).

SUMMARY

We review and summarize the existing literature and current understanding of the roles of PRL on various PRL aspects of AD and PD.

KEY MESSAGES

In general, PRL is viewed as a promising molecule for the treatment of AD and PD. Modulation of PRL functions and targeting of immune mechanisms are needed to devise preventive or therapeutic strategies.

Association between serum Sestrin2 level and diabetic peripheral neuropathy in type 2 diabetic patients

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a chronic and serious microvascular complication of diabetes linked to redox imbalance. Sestrin2, a novel inducible stress protein, participates in glucose metabolic regulation and redox homeostasis. However, the association between serum Sestrin2 and DPN is unknown.

AIM

To explore the association between serum Sestrin2 and DPN in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 96 T2DM patients and 39 healthy volunteers, matched by age and sex, participated in this cross-sectional study. Clinical features and metabolic indices were identified. Serum Sestrin2 was measured by ELISA. The association between Sestrin2 and DPN was studied. Correlation and logistic regression analyses were used to evaluate the associations of different metabolic indices with Sestrin2 and DPN.

RESULTS

The 96 patients with T2DM were divided into DPN (n = 47) and patients without DPN (n = 49). Serum Sestrin2 was significantly lower in healthy volunteers than in all T2DM patients combined [9.10 (5.41-13.53) ng/mL vs 12.75 (7.44-23.80) ng/mL, P < 0.01]. T2DM patients without DPN also had significantly higher levels of Sestrin2 than healthy volunteers [14.58 (7.93-26.62) ng/mL vs 9.10 (5.41-13.53) ng/mL, P < 0.01]. However, T2DM patients with DPN had lower circulating Sestrin2 levels compared to T2DM patients without DPN [9.86 (6.72-21.71) ng/mL vs 14.58 (7.93-26.62) ng/mL, respectively, P < 0.01]. Bivariate correlation analysis revealed that serum Sestrin2 was positively correlated with body mass index (r = 0.672, P = 0.000), hemoglobin A1c (HbA1c) (r = 0.292, P = 0.000), serum creatinine (r = 0.206, P = 0.016), triglycerides (r = 0.731, P = 0.000), and fasting glucose (r = 0.202, P = 0.040), and negatively associated with estimated glomerular filtration rate (r = -0.230, P = 0.007). After adjustment for sex, age, HbA1c, and diabetes duration, multiple regression analysis revealed that Sestrin2 was independently correlated with body mass index and triglyceride levels (P = 0.000). Logistic regression analyses indicated that Sestrin2, diabetes duration, and high-density lipoprotein were strongly associated with DPN (odds ratio = 0.855, 1.411, and 0.041, respectively).

CONCLUSION

Our results show Sestrin2 is decreased in T2DM patients with DNP. As lower Sestrin2 is independently associated with DPN, Sestrin2 may contribute to progression of DPN in T2DM patients.

Knockout of AMPKα2 Blocked the Protection of Sestrin2 Overexpression Against Cardiac Hypertrophy Induced by Pressure Overload

Objectives: Sestrin2 (Sesn2) has been demonstrated to be a cysteine sulfinyl reductase and protects cells from multiple stress insults, including hypoxia, endoplasmic reticulum stress, and oxidative stress. However, the roles and mechanisms of Sesn2 in pressure overload-induced mouse cardiac hypertrophy have not been clearly clarified. This study intended to investigate whether sestrin2 (Sesn2) overexpression could prevent pressure overload-induced cardiac hypertrophy via an AMPKα2 dependent pathway through conditional knockout of AMPKα2.

Methods and results: Sesn2 expression was significantly increased in mice hearts at 2 and 4 weeks after aortic banding (AB) surgery, but decreased to 60–70% of the baseline at 8 weeks. Sesn2 overexpression (at 3, 6, and 9 folds) showed little cardiac genetic toxicity in transgenic mice. Cardiac dysfunctions induced by pressure overload were attenuated by cardiomyocyte-specific Sesn2 overexpression when measured by echocardiography and hemodynamic analysis. Results of HE and PSR staining showed that Sesn2 overexpression significantly alleviated cardiac hypertrophy and fibrosis in mice hearts induced by pressure overload. Meanwhile, adenovirus-mediated-Sesn2 overexpression markedly suppressed angiotensin II-induced neonatal rat cardiomyocyte hypertrophy in vitro. Mechanistically, Sesn2 overexpression increased AMPKα2 phosphorylation but inhibited mTORC1 phosphorylation. The cardiac protections of Sesn2 overexpression were also via regulating oxidative stress by enhancing Nrf2/HO-1 signaling, restoring SOD activity, and suppressing NADPH activity. Particularly, we first proved the vital role of AMPKα2 in the regulation of Sesn2 with AMPKα2 knockout (AMPKα2-/-) mice and Sesn2 transgenic mice crossed with AMPKα2-/-, since Sesn2 overexpression failed to improve cardiac function, inhibit cardiac hypertrophy and fibrosis, and attenuate oxidative stress after AMPKα2 knockout.

Conclusion: This study uniquely revealed that Sesn2 overexpression showed little genetic toxicity in mice hearts and inhibited mTORC1 activation and oxidative stress to protect against pressure overload-induced cardiac hypertrophy in an AMPKα2 dependent pathway. Thus, interventions through promoting Sesn2 expression might be a potential strategy for treating pathological cardiac hypertrophy and heart failure.

Sestrin2 suppression aggravates oxidative stress and apoptosis in endothelial cells subjected to pharmacologically induced endoplasmic reticulum stress

Endoplasmic reticulum (ER) stress is an inflammatory response that contributes to endothelial cell dysfunction, a hallmark of cardiovascular diseases, in close interplay with oxidative stress. Recently, Sestrin2 (SESN2) emerged as a novel stress-inducible protein protecting cells from oxidative stress. We investigated here, for the first time, the impact of SESN2 suppression on oxidative stress and cell survival in human endothelial cells subjected to pharmacologically (thapsigargin)-induced ER stress and studied the underlying cellular pathways. We found that SESN2 silencing, though did not specifically induce ER stress, it aggravated the effects of thapsigargin-induced ER stress on oxidative stress and cell survival. This was associated with a dysregulation of Nrf-2, AMPK and mTORC1 signaling pathways. Furthermore, SESN2 silencing aggravated, in an additive manner, apoptosis caused by thapsigargin. Importantly, SESN2 silencing, unlike thapsigargin, caused a dramatic decrease in protein expression and phosphorylation of Akt, a critical pro-survival hub and component of the AMPK/Akt/mTORC1 axis. Our findings suggest that patients with conditions characterized by ER stress activation, such as diabetes, may be at higher risk for cardiovascular complications if their endogenous ability to stimulate and/or maintain expression levels of SESN2 is disturbed or impaired. Therefore, identifying novel or repurposing existing pharmacotherapies to enhance and/or maintain SESN2 expression levels would be beneficial in these conditions.

Investigation of the levels of circulating miR-29a, miR-122, sestrin 2 and inflammatory markers in obese children with/without type 2 diabetes: a case control study

AIM

The present work investigated serum levels of miR-29a, miR-122 and sestrin2 in obese children with/without type-2-diabetes mellitus (T2DM), and their correlations with inflammatory, metabolic and anthropometric parameters.

METHODS

The study included 298 children, divided into: G1 (control, n = 136), G2 (obese without diabetes, n = 90) and G3 (obese with T2DM, n = 72). Metabolic and anthropometric parameters, miR-29a, miR-122 relative expressions, and sestrin2, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) levels were measured by their specific methods. The data was processed and analyzed by SPSS V.26 using the corresponding tests. After testing the variables' normality, Kruskal-Wallis one-way-ANOVA, Spearman correlations coefficient were used.

RESULTS

Significant higher serum miR-29a, miR-122, IL-6, hsCRP and TNF-α and lower sestrin2 levels were found in G2 and G3 than G1 and in G3 than G2 (p= > 0.001 for all). Especially in G3, miR-29a and miR-122 levels correlated positively while sestrin2 levels correlated negatively with waist circumference and BMI percentiles, serum levels of LDL-cholesterol, triacylglycerol, total cholesterol, HbA1c%, glucose, insulin, c-peptide, homeostatic model assessment-insulin resistance (HOMA-IR), IL-6, hsCRP and TNF-α.

CONCLUSION

The change in the serum miR-29a, miR-122 and sestrin2 levels in obese children with/without T2DM may suggest a possible role of these biomarkers in the pathogenesis of childhood obesity and their accompanied complications e.g. inflammations and T2DM. Also, further studies are required to test drugs that antagonize the action miR-29a and miR-122 or upregulate sestrin2 in the management of these cases.

Sestrin2 in hypoxia and hypoxia-related diseases

Objectives: Sestrin2 is a stress-inducible protein and play an important role in adapting stress states of cells. This article reviewed the role of Sestrin2 in hypoxia and hypoxia-related diseases to provide new perspectives for future research and new therapeutic targets for hypoxia-related diseases.

Methods: A review was conducted through an electronic search of PubMed and Medline databases. Keywords included Sestrin2, ROS, hypoxia, and hypoxia-related disease. Articles from 2008 to 2021 were mostly included and older ones were not excluded.

Results: Sestrin2 is upregulated under various stress conditions, especially hypoxia. Under hypoxic condition, Sestrin2 plays a protective role by reducing the generation of ROS through various pathways, such as adenosine monophosphatea-ctivated protein kinase (AMPK) / mammalian target of rapamycin (mTOR) pathway and nuclear factor-E2-related factor2 (Nrf2) pathway. In addition, Sestrin2 is involved in various hypoxia-related diseases, such as cerebral hypoxic disease, myocardial hypoxic disease, hypoxia-related respiratory disease, and diabetes.

Discussion: Sestrin2 is involved in various hypoxia-related diseases and maybe a therapeutic target. Furthermore, most studies focus on cerebral and myocardial ischemia reperfusion. More researches on hypoxia-related respiratory diseases, kidney injury, and diabetes are needed in future.

Sestrins as modulators of aging processes and diseases related to age

Sestrins are highly conserved proteins that regulate cell growth, metabolism, survival and proliferation under oxidative stress, genotoxic stress, hypoxia or endoplasmic reticulum stress. Sestrins affect cell signaling by inhibiting the production of reactive oxygen species, activating the AMP-activated protein kinase (AMPK), inhibiting the mTOR pathway and acting as a positive regulator of autophagy. Therefore, their protective role against cancer, metabolic disorders, cardiovascular diseases and neurodegeneration is increasingly being postulated. The article describes the mechanisms of action of sestrins and their meaning in aging and age-related diseases. The latest studies indicating their physiological significance and role in key signaling pathways controlling the cell metabolism and survival under stress conditions were also discussed.

Sestrin2 and mitochondrial quality control: Potential impact in myogenic differentiation

Mitochondria are highly dynamic organelles capable of adapting their network, morphology, and function, playing a role in oxidative phosphorylation and many cellular processes in most cell types. Skeletal muscle is a very plastic tissue, subjected to many morphological changes following diverse stimuli, such as during myogenic differentiation and regenerative myogenesis. For some time now, mitochondria have been reported to be involved in myogenesis by promoting a bioenergetic remodeling and assisting myoblasts in surviving the process. However, not much is known about the interplay between mitochondrial quality control and myogenic differentiation. Sestrin2 (SESN2) is a well described regulator of autophagy and antioxidant responses and has been gaining attention due to its role in aging-associated pathologies and redox signaling promoted by reactive oxygen species (ROS) in many tissues. Current evidence involving SESN2-associated pathways suggest that it can act as a potential regulator of mitochondrial quality control following induction by ROS under stress conditions, such as during myogenesis. Yet, there are no studies directly assessing SESN2 involvement in myogenic differentiation. This review provides novel insights pertaining the involvement of SESN2 in myogenic differentiation by analyzing the interactions between ROS and mitochondrial remodeling.

Sestrin2 is an endogenous antioxidant that improves contractile function in the heart during exposure to ischemia and reperfusion stress

Sestrin2 (Sesn2) is a stress-inducible protein that plays a critical role in the response to ischemic stress. We recently recognized that Sesn2 may protect the heart against ischemic insults by reducing the generation of reactive oxygen species (ROS). After 45 min of ischemia followed by 24 h of reperfusion, myocardial infarcts were significantly larger in Sesn2 KO hearts than in wild-type hearts. Isolated cardiomyocytes from wild-type hearts treated with hypoxia and reoxygenation (H/R) stress showed significantly greater Sesn2 levels, compared with normoxic hearts (p < 0.05). Intriguingly, the administration of adeno-associated virus 9-Sesn2 into Sesn2 knockout (KO) hearts rescued Sesn2 protein levels and significantly improved the cardiac function of Sesn2 KO mice exposed to ischemia and reperfusion. The rescued levels of Sesn2 in Sesn2 KO hearts significantly ameliorated ROS generation and the activation of ROS-related stress signaling pathways during ischemia and reperfusion. Moreover, the rescued Sesn2 levels in Sesn2 KO cardiomyocytes improved the maximal velocity of cardiomyocyte shortening by H/R stress. Rescued Sesn2 levels also improved peak height, peak shortening amplitude, and maximal velocity of the re-lengthening of Sesn2 KO cardiomyocytes subjected to H/R. Finally, the rescued Sesn2 levels significantly augmented intracellular calcium levels and reduced the mean time constant of transient calcium decay in Sesn2 KO cardiomyocytes exposed to H/R. Overall, these findings indicated that Sesn2 can act as an endogenous antioxidant to maintain intracellular redox homeostasis under ischemic stress conditions.

The potential role of sestrin 2 in liver regeneration

Liver regeneration is a remarkably complex phenomenon conserved across all vertebrates, enabling the restoration of lost liver mass in a matter of days. Unfortunately, extensive damage to the liver may compromise this process, often leading to the death of affected individuals. Ischemia/reperfusion injury (IRI) is a common source of damage preceding regeneration, often present during liver transplantation, resection, trauma, or hemorrhagic shock. Increased oxidative stress and mitochondrial dysfunction are key hallmarks of IRI, which can jeopardize the liver's ability to regenerate. Therefore, a better understanding of both liver regeneration and IRI is of important clinical significance. In the current review, we discuss the potential role of sestrin 2 (SESN2), a novel anti-aging protein, in liver regeneration and ischemia/reperfusion preceding regeneration. We highlight its beneficial role in protecting cells from mitochondrial dysfunction and oxidative stress as key aspects of its involvement in liver regeneration. Additionally, we describe how its ability to promote the expression of Nrf2 bears significant importance in this context. Finally, we focus on a potential novel link between SESN2, mitohormesis and ischemic preconditioning, which could explain some of the protective effects of preconditioning.

Sestrin 2, a potential star of antioxidant stress in cardiovascular diseases

Physiological reactive oxygen species (ROS) play an important role in cellular signal transduction. However, excessive ROS is an important pathological mechanism in most cardiovascular diseases (CVDs), such as myocardial aging, cardiomyopathy, ischemia/reperfusion injury (e.g., myocardial infarction) and heart failure. Programmed cell death, hypertrophy and fibrosis may be due to oxidative stress. Sestrin 2 (Sesn2), a stress-inducible protein associated with various stress conditions, is a potential antioxidant. Sesn2 can suppress the process of heart damage caused by oxidative stress, promote cell survival and play a key role in a variety of CVDs. This review discusses the effect of Sesn2 on the redox signal, mainly via participation in the signaling pathway of nuclear factor erythroid 2-related factor 2, activation of adenosine monophosphate-activated protein kinase and inhibition of mammalian target of rapamycin complex 1. It also discusses the effect of Sesn2's antioxidant activity on different CVDs. We speculate that Sesn2 plays an important role in CVDs by stimulating the process of antioxidation and promoting the adaptation of cells to stress conditions and/or the environment, opening a new avenue for related therapeutic strategies.

The Protective Role of Sestrin2 in Atherosclerotic and Cardiac Diseases

Atherosclerotic disease, such as coronary artery disease (CAD), is known to be a chronic inflammatory disease, as well as an age-related disease. Excessive oxidative stress produced by reactive oxygen species (ROS) contributes to the pathogenesis of atherosclerosis. Sestrin2 is an anti-oxidant protein that is induced by various stresses such as hypoxia, DNA damage, and oxidative stress. Sestrin2 is also suggested to be associated with aging. Sestrin2 is expressed and secreted mainly by macrophages, endothelial cells, and cardiomyocytes. Sestrin2 plays an important role in suppressing the production and accumulation of ROS, thus protecting cells from oxidative damage. Since sestrin2 is reported to have anti-oxidant and anti-inflammatory properties, it may play a protective role against the progression of atherosclerosis and may be a potential therapeutic target for the amelioration of atherosclerosis. Regarding the association between blood sestrin2 levels and atherosclerotic disease, the blood sestrin2 levels in patients with CAD or carotid atherosclerosis were reported to be high. High blood sestrin2 levels in patients with such atherosclerotic disease may reflect a compensatory response to increased oxidative stress and may help protect against the progression of atherosclerosis. This review describes the protective role of sestrin2 against the progression of atherosclerotic and cardiac diseases.

Role of Inflammation in Vascular Disease-Related Perivascular Adipose Tissue Dysfunction

Perivascular adipose tissue (PVAT) is the connective tissue around most blood vessels throughout the body. It provides mechanical support and maintains vascular homeostasis in a paracrine/endocrine manner. Under physiological conditions, PVAT has anti-inflammatory effects, improves free fatty acid metabolism, and regulates vasodilation. In pathological conditions, PVAT is dysfunctional, secretes many anti-vasodilator factors, and participates in vascular inflammation through various cells and mediators; thus, it causes dysfunction involving vascular smooth muscle cells and endothelial cells. Inflammation is an important pathophysiological event in many vascular diseases, such as vascular aging, atherosclerosis, and hypertension. Therefore, the pro-inflammatory crosstalk between PVAT and blood vessels may comprise a novel therapeutic target for the prevention and treatment of vascular diseases. In this review, we summarize findings concerning PVAT function and inflammation in different pathophysiological backgrounds, focusing on the secretory functions of PVAT and the crosstalk between PVAT and vascular inflammation in terms of vascular aging, atherosclerosis, hypertension, diabetes mellitus, and other diseases. We also discuss anti-inflammatory treatment for potential vascular diseases involving PVAT.

Sestrin2 as a Potential Target for Regulating Metabolic-Related Diseases

Sestrin2 is a highly conserved protein that can be induced under a variety of stress conditions, including DNA damage, oxidative stress, endoplasmic reticulum (ER) stress, and metabolic stress. Numerous studies have shown that the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) signaling pathway has a crucial role in the regulation of metabolism. Sestrin2 regulates metabolism via a number of pathways, including activation of AMPK, inhibition of the mTOR complex 1 (mTORC1), activation of mTOR complex 2 (mTORC2), inhibition of ER stress, and promotion of autophagy. Therefore, modulation of Sestrin2 activity may provide a potential therapeutic target for the prevention of metabolic diseases such as insulin resistance, diabetes, obesity, non-alcoholic fatty liver disease, and myocardial ischemia/reperfusion injury. In this review, we examined the regulatory relationship between Sestrin2 and the AMPK/mTOR signaling pathway and the effects of Sestrin2 on energy metabolism.

Sestrin2 protects against traumatic brain injury by reinforcing the activation of Nrf2 signaling

Sestrin2 (SESN2) is stress-inducible protein that confers cytoprotective effects against various noxious stimuli. Accumulating evidence has documented that SESN2 has potent anti-apoptosis and anti-oxidative stress functions. However, whether it provides neuroprotection in traumatic brain injury (TBI) models remains unexplored. The purpose of this study was to explore the regulatory effect of SESN2 on TBI using in vivo and in vitro models. We found that TBI resulted in a marked induction of SESN2 in the cerebral cortex tissues of mice. SESN2 overexpression in the brain by in vivo gene transfer significantly decreased neurological deficit, brain edema, and neuronal apoptosis of mice with TBI. Moreover, the overexpression of SESN2 significantly decreased the oxidative stress induced by TBI in mice. In vitro studies of TBI demonstrated that SESN2 overexpression decreased apoptosis and oxidative stress in scratch-injured cortical neurons. Notably, SESN2 overexpression increased the nuclear levels of nuclear factor-erythroid 2-related factor 2 (Nrf2) and enhanced the activation of Nrf2 antioxidant signaling in in vivo and in vitro models of TBI. In addition, the inhibition of Nrf2 significantly abolished SESN2-mediated neuroprotective effects in vivo and in vitro. In conclusion, these results of our work demonstrate that SESN2 protects against TBI by enhancing the activation of Nrf2 antioxidant signaling.

Regulatory mechanisms of Sesn2 and its role in multi-organ diseases

Sestrin2 (Sesn2) is a powerful anti-oxidant that can prevent acute and chronic diseases. The role of Sesn2 has been thoroughly reviewed in liver, nervous system, and immune system diseases. However, there is a limited number of reviews that have summarized the effects of Sesn2 in heart and vascular diseases, and very less literature-based information is available on involvement of Sesn2 in renal and respiratory pathologies. This review summarizes the latest research on Sesn2 in multi-organ stress responses, with a particular focus on the protective role of Sesn2 in cardiovascular, respiratory, and renal diseases, emphasizing the potential therapeutic benefit of targeting Sesn2 in stress-related diseases.

SESTRINs: Emerging Dynamic Stress-Sensors in Metabolic and Environmental Health

Proper timely management of various external and internal stresses is critical for metabolic and redox homeostasis in mammals. In particular, dysregulation of mechanistic target of rapamycin complex (mTORC) triggered from metabolic stress and accumulation of reactive oxygen species (ROS) generated from environmental and genotoxic stress are well-known culprits leading to chronic metabolic disease conditions in humans. Sestrins are one of the metabolic and environmental stress-responsive groups of proteins, which solely have the ability to regulate both mTORC activity and ROS levels in cells, tissues and organs. While Sestrins are originally reported as one of several p53 target genes, recent studies have further delineated the roles of this group of stress-sensing proteins in the regulation of insulin sensitivity, glucose and fat metabolism, and redox-function in metabolic disease and aging. In this review, we discuss recent studies that investigated and manipulated Sestrins-mediated stress signaling pathways in metabolic and environmental health. Sestrins as an emerging dynamic group of stress-sensor proteins are drawing a spotlight as a preventive or therapeutic mechanism in both metabolic stress-associated pathologies and aging processes at the same time.

Protective response of Sestrin under stressful conditions in aging

The aging at cellular level manifests itself in the form of uncontrolled formation of ROS, chronic inflammation, and increased susceptibility to cellular stress. Aging is often regarded as a risk factor for several diseases due to several age-associated pathological changes in cells. Sestrin (Sesn) is an important molecule for controlling normal cellular physiology and play a significant role in the progression of certain age-associated cellular pathologies. This review deals with the structure, function, regulation, signaling network, and the potential role of Sesn in age-associated cellular pathophysiology. The cellular response mediated by Sesn under stressful conditions and rescue mechanism is discussed. It would be interesting to find out the precise physiological role of Sesn in the regulation of cellular aging. The anti-aging activity of Sesn may benefit to prevent various age-associated diseases and have clinical utility in diagnostic and therapeutic intervention.

Substrate metabolism regulated by Sestrin2-mTORC1 alleviates pressure overload-induced cardiac hypertrophy in aged heart

Sestrin2 (Sesn2) is a stress sensor for the mammalian target of rapamycin complex 1 (mTORC1) pathway. Aging impairs cardiac mTORC1 activation, thereby sensitizing the heart to hypertrophy. C57BL/6 J young wild-type (young WT; 4-6 months), aged WT (24-26 months), and young Sestrin2 knockout mice (Y-Sesn2 KO; 4-6 months) underwent transverse aortic constriction (TAC) for pressure overload. Cardiac expression of Sesn2 decreased with age. At 4 weeks after TAC, aged WT and Y-Sesn2 KO exhibited larger hearts and impaired cardiac function, compared with young WT mice. Augmented phosphorylation of mTOR and downstream effectors; damaged mitochondria and elevated redox markers, as well as and impaired glucose and fatty acid oxidation were observed in aged WT and Y-Sesn2 KO hearts. A pressure overload-induced interaction between Sesn2 and GTPase-activating protein activity toward Rags 2 (GATOR2), which positively regulates mTORC1, was impaired in aged WT hearts. Adeno-associated virus 9-Sesn2 treatment rescued Sesn2 expression, attenuated mTORC1 activation, and increased pressure overload tolerance in aged WT and Y-Sesn2 KO hearts. These results indicated that cardiac Sesn2 acts as a pressure overload sensor for mTORC1. Furthermore, Sesn2 deficiency may cause increased sensitivity to hypertrophy in elderly individuals.

Association between Plasma Sestrin2 Levels and the Presence and Severity of Coronary Artery Disease

Aims

Atherosclerotic disease, such as coronary artery disease (CAD), is recognized to be associated with inflammation and oxidative stress. We investigated the association between CAD and plasma levels of sestrin2 which is one of the stress-inducible antioxidant proteins.

Methods

We measured plasma sestrin2 levels in 304 patients undergoing elective coronary angiography. The severity of CAD was represented as the numbers of >50% stenotic coronary vessels and segments and the severity score.

Results

CAD was found in 175 patients, of whom 73 had 1-vessel (1-VD), 59 had 2-vessel (2-VD), and 43 had 3-vessel disease (3-VD). Plasma sestrin2 levels were significantly higher in 175 patients with CAD than in 129 without CAD (median 16.4 vs. 14.2 ng/mL, P < 0.05). A stepwise increase in sestrin2 levels was found depending on the number of >50% stenotic coronary vessels: 14.2 in CAD(-), 15.4 in 1-VD, 17.3 in 2-VD, and 17.7 ng/mL in3-VD (P < 0.05). High sestrin2 level (>16.0 ng/mL) was present in 38% of patients with CAD(-), 47% of 1-VD, 66% of 2-VD, and 53% of 3-VD (P < 0.005). Sestrin2 levels significantly, but weakly, correlated with the number of >50% stenotic segments and the severity score (rs = 0.12 and rs = 0.13, P < 0.05). In the multivariate analysis, sestrin2 levels were a significant factor associated with CAD independent of atherosclerotic risk factors. The odds ratio for CAD was 1.79 (95%CI = 1.09-2.95) for high sestrin2 level of >16.0 ng/mL (P < 0.025).

Conclusions

Plasma sestrin2 levels in patients with CAD were found to be high and to be associated with the severity of CAD. High sestrin2 levels in patients with CAD may reflect a protective response against the progression of CAD.

Impact of age on N-methyl-N-nitrosourea induced microsatellite instability in young and old C57BL/6J mice

Age is an important factor in the evaluation of chemical toxicology. Chemical carcinogenic compounds can induce genomic mutations. However, few studies have been conducted on the association between genomic mutation frequency, such as microsatellite instability (MSI), and the age of mice treated with a nitrosourea mutagen. In the current work, we treated young (6 weeks) and old (10 months) mice with N-methyl-N-nitrosourea (MNU) for 4 months; the MSI frequency was then measured using polymerase chain reaction (PCR) and short tandem repeat (STR) scanning. The percentage of animals with MSI in the old group was significantly higher than that in the young group (100% and 75%). The frequency of MSI events was significantly different between the two groups as well (15.8% for old and 9.4% for young). The ratio of MSI loci displayed no obvious difference between the two groups. In addition, a few loci, including D15Mit5 and D8Mit14 exhibited the highest frequency of MSI events. Since specific loci showed increased MSI in the present study and a higher frequency in previous studies, these loci could be regarded as "hot spot". These results suggested that old mice would be more susceptible to this mutagen, and prone to accrue MSI. The hot spot microsatellite loci are potentially useful markers for genomic instability analysis.

Sestrin2 as a potential therapeutic target for cardiovascular diseases

Sestrin2 is a cysteine sulfinyl reductase that plays crucial roles in regulation of antioxidant actions. Sestrin2 provides cytoprotection against multiple stress conditions, including hypoxia, endoplasmic reticulum (ER) stress and oxidative stress. Recent research reveals that upregulation of Sestrin2 is induced by various transcription factors such as p53 and activator protein 1 (AP-1), which further promotes AMP-activated protein kinase (AMPK) activation and inhibits mammalian target of rapamycin protein kinase (mTOR) signaling. Sestrin2 triggers autophagy activity to reduce cellular reactive oxygen species (ROS) levels by promoting nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) activation and Kelch-like ECH-associated protein 1 (Keap1) degradation, which plays a pivotal role in homeostasis of metabolic regulation. Under hypoxia and ER stress conditions, elevated Sestrin2 expression maintains cellular homeostasis through regulation of antioxidant genes. Sestrin2 is responsible for diminishing cellular ROS accumulation through autophagy via AMPK activation, which displays cardioprotection effect in cardiovascular diseases. In this review, we summarize the recent understanding of molecular structure, biological roles and biochemical functions of Sestrin2, and discuss the roles and mechanisms of Sestrin2 in autophagy, hypoxia and ER stress. Understanding the precise functions and exact mechanism of Sestrin2 in cellular homeostasis will provide the evidence for future experimental research and aid in the development of novel therapeutic strategies for cardiovascular diseases.