Increased plasma sestrin2 concentrations in patients with chronic heart failure and predicted the occurrence of major adverse cardiac events: A 36-month follow-up cohort study

N-Acetylcysteine Alleviates Necrotizing Enterocolitis by Depressing SESN2 Expression to Inhibit Ferroptosis in Intestinal Epithelial Cells

Abstract-Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease in neonates, and effective strategies to prevent and treat NEC are still lacking. Studies have shown that N-acetylcysteine (NAC) has protective effects against NEC, however, the specific mechanism underlying its effects on intestinal functions remains unclear. Recently, NAC has been shown to suppress ferroptosis in many diseases, while it is unclear whether the beneficial effects of NAC on NEC are related to ferroptosis. In this study, we revealed that ferroptosis was significantly induced in intestinal samples from infants with NEC. NAC alleviated intestinal inflammation, barrier damage and ferroptosis in multifactorial NEC models in vivo and in vitro. Sestrin2 (SESN2) was identified as an important mediator of NAC-induced ferroptosis resistance in intestinal epithelial cells. Furthermore, SESN2 knockdown inhibited the inflammatory response, alleviated barrier damage and ferroptosis in intestinal epithelial cells and enhanced the protective effects of NAC to a certain extent. Conversely, cells overexpressing SESN2 showed the opposite changes. In summary, our study demonstrated that NAC attenuates NEC progression by decreasing SESN2 expression to inhibit ferroptosis in intestinal epithelial cells, suggesting that NAC might be an effective clinical treatment for NEC.

Significance of serum sestrin2 as a biomarker of severity and functional outcome in acute intracerebral hemorrhage: a prospective observational longitudinal study

BACKGROUND

Sestrin2 is a highly conserved stress-inducible protein with neuroprotective properties. Herein, we investigated the prognostic significance of serum sestrin2 in human intracerebral hemorrhage (ICH).

METHODS

In this prospective observational longitudinal study, we enrolled 126 patients with supratentorial ICH as cases together with 126 healthy individuals as controls. Severity indicators were National Institutes of Health Stroke Scale (NIHSS) and hematoma volume. Prognostic parameters were early neurologic deterioration (END) and post-stroke 6-month poor prognosis [modified Rankin Scale (mRS) scores of 3-6]. Multivariate analysis was performed to assess relations of serum sestrin2 levels to severity and prognosis.

RESULTS

Patients had statistically significantly higher serum sestrin2 levels than controls. Serum sestrin2 levels of patients were independently correlated with NIHSS scores and hematoma volume, as well as were substantially elevated in order of mRS scores from 0 to 6. Serum sestrin2 was identified as an independent predictor of END and poor prognosis. Based on the receiver operating characteristic curve, serum sestrin2 had a similar predictive ability for END and poor prognosis, as compared to NIHSS scores and hematoma volume. Prediction models of END and poor prognosis, in which serum sestrin2, NIHSS scores and hematoma volume were integrated, were visually described via nomogram, were reliable and stable under calibration curve and were of clinical benefit using decision curve analysis. Also, prediction model of poor prognosis showed dramatically higher discriminatory efficiency than any of NIHSS scores, hematoma volume and serum sestrin2.

CONCLUSION

Serum sestrin2 levels, which are obviously increased following acute ICH, are independently related to illness severity and poor clinical outcomes, substantializing serum sestrin2 as a clinically valuable prognostic biomarker of ICH.

Sestrin2 in diabetes and diabetic complications

Diabetes is a global health problem which is accompanied with multi-systemic complications. It is of great significance to elucidate the pathogenesis and to identify novel therapies of diabetes and diabetic complications. Sestrin2, a stress-inducible protein, is primarily involved in cellular responses to various stresses. It plays critical roles in regulating a series of cellular events, such as oxidative stress, mitochondrial function and endoplasmic reticulum stress. Researches investigating the correlations between Sestrin2, diabetes and diabetic complications are increasing in recent years. This review incorporates recent findings, demonstrates the diverse functions and regulating mechanisms of Sestrin2, and discusses the potential roles of Sestrin2 in the pathogenesis of diabetes and diabetic complications, hoping to highlight a promising therapeutic direction.

Sestrin2 protects against hypoxic nerve injury by regulating mitophagy through SESN2/AMPK pathway

Hypoxia induced by high altitude can lead to severe neurological dysfunction. Mitophagy is known to play a crucial role in hypoxic nerve injury. However, the regulatory mechanism of mitophagy during this injury remains unclear. Recent studies have highlighted the role of Sestrin2 (SESN2), an evolutionarily conserved stress-inducible protein against acute hypoxia. Our study demonstrated that hypoxia treatment increased SESN2 expression and activated mitophagy in PC12 cells. Furthermore, the knock-out of Sesn2 gene led to a significant increase in mitochondrial membrane potential and ATP concentrations, which protected the PC12 cells from hypoxic injury. Although the AMPK/mTOR pathway was significantly altered under hypoxia, it does not seem to participate in mitophagy regulation. Instead, our data suggest that the mitophagy receptor FUNDC1 plays a vital role in hypoxia-induced mitophagy. Moreover, SESN2 may function through synergistic regulation with other pathways, such as SESN2/AMPK, to mediate cellular adaptation to hypoxia, including the regulation of mitophagy in neuron cells. Therefore, SESN2 plays a critical role in regulating neural cell response to hypoxia. These findings offer valuable insights into the underlying molecular mechanisms governing the regulation of mitophagy under hypoxia and further highlight the potential of SESN2 as a promising therapeutic target for hypoxic nerve injury.

Muscular Sestrins: Roles in Exercise Physiology and Stress Resistance

Sestrins are a family of stress-inducible proteins that are critical for stress adaptation and the maintenance of metabolic homeostasis. High expression of Sestrins is observed in skeletal and cardiac muscle tissues, suggesting their significance in the physiological homeostasis of these organs. Furthermore, expression of Sestrins is dynamically controlled in the tissues, based on the level of physical activity and the presence or absence of stress insults. Genetic studies in model organisms have shown that muscular Sestrin expression is critical for metabolic homeostasis, exercise adaptation, stress resistance, and repair and may mediate the beneficial effects of some available therapeutics. The current minireview summarizes and discusses recent findings that shed light on the role of Sestrins in regulating muscle physiology and homeostasis.

Utilizing shared frailty with the Cox proportional hazards regression: Post discharge survival analysis of CHF patients

Understanding patients' survival probability as well as the factors affecting it constitute a significant concern for researchers and practitioners, in particular for patients with severe chronic illnesses such as congestive heart failure (CHF). CHF is a clinical syndrome characterized by comorbidities and adverse medical events. Risk stratification to identify patients most likely to die shortly after hospital discharge can improve the quality of care by better allocating organizational resources and personalized interventions. Probability assessment improves clinical decision-making, contributes to personalized care, and saves costs. Although one of the most informative indices is the time to an adverse event for each patient, commonly analyzed using survival analysis methods, these are often challenging to implement due to the complexity of the medical data. Numerous studies have used the Cox proportional hazards (PH) regression method to generate the survival distribution pattern and factors affecting survival. This model, although advantageous for survival analysis, assumes the homogeneity of the hazard ratio across patients and independence of the observations in terms of survival time. These assumptions are often violated in real-world data, especially when the dataset is composed of readmission data for chronically ill patients, since these recurring observations are inherently dependent. This study ran the Cox PH regression on a feature set selected by machine learning algorithms from a rich hospital dataset. The event modeled here was patient mortality within 90 days post-hospital discharge. The sample was composed of medical records of patients hospitalized in the Israeli Sheba Medical Center more than once, with CHF as the primary diagnosis. We modeled the survival of CHF patients using the Cox PH regression with and without the shared frailty correction that addresses the shortcomings of the Cox Model. The results of the two models of the Cox PH regression - with and without the shared frailty correction were compared. The results demonstrate that the shared frailty correction, which was statistically significant in our analysis, improved the performance of the basic Cox PH model. While this is the main contribution, we also show that this model outperforms two commonly used measures (ADHERE and EFFECT) for predicting early mortality of CHF patients. Thus, the results illustrate how applying advanced analytics can outperform traditional methods. An additional contribution is the feature set selected using machine-learning methods that is different from those used in the extant literature.

Serum Sestrin2 Was Lower in Septic Shock Patients with Cardiomyopathy

Background

To determine the clinical significance of variations in serum sestrin2 protein levels in the development of septic cardiomyopathy in septic shock patients.

Methods

The serum sestrin2 concentrations of each sample were determined using ELISA in a total of 67 control persons and 188 patients with septic shock. Furthermore, using transthoracic echocardiography, septic shock patients were split into two groups based on whether or not cardiomyopathy had developed, and the differences in each index between the two groups were analyzed. We looked at the relationship between serum sestrin2 levels, norepinephrine dosage, and NTproBNP levels. The influencing variables for the prediction of septic cardiomyopathy linked with the development of septic cardiomyopathy and clinical prognosis in septic cardiomyopathy were determined using multivariate binary logistic regression.

Results

Assessment of left ventricular systolic function by measurement of LVEF revealed that 61/188 (32.4%) of the 188 patients with septic shock included in the research satisfied the diagnostic criteria for septic cardiomyopathy. (1) Sestrin2 protein levels showed a significant difference between septic shock and healthy controls (p < 0.01). (2) Compared to the group without septic cardiomyopathy, the group with combined septic cardiomyopathy had lower serum sestrin2 protein levels (p < 0.05), lower systolic blood pressure (p < 0.05), and higher plasma NTproBNP levels (p < 0.01) and used greater norepinephrine dosages (p < 0.01). The levels of serum sestrin2 protein revealed a little negative relationship with NTproBNP and norepinephrine dose. However, a binary logistic regression analysis revealed that none of these factors was an independent predictor of septic shock. (3) Age, lactate level, SOFA score, positive bacteremia, and sestrin2 protein were shown to be substantial discrepancies in clinical outcomes in patients with septic cardiomyopathy, becoming variables that impact clinical outcomes. Positive bacteremia (p = 0.031, OR = 5.084), SOFA score (p = 0.021, OR = 1.304), and sestrin2 protein (p =  0.039, OR = 0.897) were revealed to have independent influences in predicting clinical mortality outcome in septic cardiomyopathy using multivariate binary logistic regression.

Conclusion

High serum sestrin2 levels clearly distinguish septic shock patients from healthy controls, whereas low serum sestrin2 levels are related with cardiac dysfunction to some extent but are not an independent influence factor for septic cardiomyopathy. Low serum sestrin2 levels were shown to be useful in predicting clinical outcome in patients with septic cardiomyopathy.

Oxidative Stress-Induced Protein of SESTRIN2 in Cardioprotection Effect

Because of the rich mitochondria and high energy metabolic requirements, excessive oxidative stress generated by ROS is a key pathogenic mechanism in heart disease. SESTRIN2, the well-known antioxidant protein, plays a vital role in diminishing the production and accumulation of ROS, thus sparing cells from oxidative damage. From this new perspective, we first examine SESTRIN2 structure-function relationships; then, we describe how SESTRIN2 expression is regulated under oxidative stress conditions, emphasizing SESTRIN2's antioxidant mechanism via multiple signal transductions; and finally, we discuss SESTRIN2's role in a variety of oxidative stress-related cardiac diseases, including age-related heart disease, diabetic cardiomyopathy, ischemia-reperfusion myocardial injury, septic cardiomyopathy, and chronic cardiac insufficiency. The goal of this review is to identify the SESTRIN2 protein as a potential biomarker and new therapy target for oxidative stress-related cardiac diseases.

Sestrin2 in cancer: a foe or a friend?

Sestrin2 is a conserved antioxidant, metabolism regulator, and downstream of P53. Sestrin2 can suppress oxidative stress and inflammation, thereby preventing the development and progression of cancer. However, Sestrin2 attenuates severe oxidative stress by activating nuclear factor erythroid 2-related factor 2 (Nrf2), thereby enhancing cancer cells survival and chemoresistance. Sestrin2 inhibits endoplasmic reticulum stress and activates autophagy and apoptosis in cancer cells. Attenuation of endoplasmic reticulum stress and augmentation of autophagy hinders cancer development but can either expedite or impede cancer progression under specific conditions. Furthermore, Sestrin2 can vigorously inhibit oncogenic signaling pathways through downregulation of mammalian target of rapamycin complex 1 (mTORC1) and hypoxia-inducible factor 1-alpha (HIF-1α). Conversely, Sestrin2 decreases the cytotoxic activity of T cells and natural killer cells which helps tumor cells immune evasion. Sestrin2 can enhance tumor cells viability in stress conditions such as glucose or glutamine deficiency. Cancer cells can also upregulate Sestrin2 during chemotherapy or radiotherapy to attenuate severe oxidative stress and ER stress, augment autophagy and resist the treatment. Recent studies unveiled that Sestrin2 is involved in the development and progression of several types of human cancer. The effect of Sestrin2 may differ depending on the type of tumor, for instance, several studies revealed that Sestrin2 protects against colorectal cancer, whereas results are controversial regarding lung cancer. Furthermore, Sestrin2 expression correlates with metastasis and survival in several types of human cancer such as colorectal cancer, lung cancer, and hepatocellular carcinoma. Targeted therapy for Sestrin2 or regulation of its expression by new techniques such as non-coding RNAs delivery and vector systems may improve cancer chemotherapy and overcome chemoresistance, metastasis and immune evasion that should be investigated by future trials.

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.

Target Sestrin2 to Rescue the Damaged Organ: Mechanistic Insight into Its Function

Sestrin2 is a stress-inducible metabolic regulator and a conserved antioxidant protein which has been implicated in the pathogenesis of several diseases. Sestrin2 can protect against atherosclerosis, heart failure, hypertension, myocardial infarction, stroke, spinal cord injury neurodegeneration, nonalcoholic fatty liver disease (NAFLD), liver fibrosis, acute kidney injury (AKI), chronic kidney disease (CKD), and pulmonary inflammation. Oxidative stress and cellular damage signals can alter the expression of Sestrin2 to compensate for organ damage. Different stress signals such as those mediated by P53, Nrf2/ARE, HIF-1α, NF-κB, JNK/c-Jun, and TGF-β/Smad signaling pathways can induce Sestrin2 expression. Subsequently, Sestrin2 activates Nrf2 and AMPK. Furthermore, Sestrin2 is a major negative regulator of mTORC1. Sestrin2 indirectly regulates the expression of several genes and reprograms intracellular signaling pathways to attenuate oxidative stress and modulate a large number of cellular events such as protein synthesis, cell energy homeostasis, mitochondrial biogenesis, autophagy, mitophagy, endoplasmic reticulum (ER) stress, apoptosis, fibrogenesis, and lipogenesis. Sestrin2 vigorously enhances M2 macrophage polarization, attenuates inflammation, and prevents cell death. These alterations in molecular and cellular levels improve the clinical presentation of several diseases. This review will shed light on the beneficial effects of Sestrin2 on several diseases with an emphasis on underlying pathophysiological effects.

Sestrin2 in atherosclerosis

Atherosclerosis (AS) is the pathological basis of numerous lethal diseases, such as myocardial infarction, heart failure, and stroke. As we know, almost twenty million people worldwide die of the arterial diseases annually. Sestrin2 is a stress-inducing protein, which serves as a guardian by activating AMPK, inhibiting mTOR, and maintaining redox balance beneath various stress environments. A large number of studies show that Sestrin2 would shield the body from injury by stress. Moreover, it has been demonstrated that Sestrin2 is closely connected with AS. Here, this article reviewed the involvement of Sestrin2 in the pathogenesis of AS from four aspects: cellular mechanism, oxidative stress, inflammation, and lipid metabolism. Current evidence reveals that Sestrin2 is a novel target for the prevention and treatment of AS.

Potential Roles of Sestrin2 in Alzheimer's Disease: Antioxidation, Autophagy Promotion, and Beyond

Alzheimer’s disease (AD) is the most common age-related neurodegenerative disease. It presents with progressive memory loss, worsens cognitive functions to the point of disability, and causes heavy socioeconomic burdens to patients, their families, and society as a whole. The underlying pathogenic mechanisms of AD are complex and may involve excitotoxicity, excessive generation of reactive oxygen species (ROS), aberrant cell cycle reentry, impaired mitochondrial function, and DNA damage. Up to now, there is no effective treatment available for AD, and it is therefore urgent to develop an effective therapeutic regimen for this devastating disease. Sestrin2, belonging to the sestrin family, can counteract oxidative stress, reduce activity of the mammalian/mechanistic target of rapamycin (mTOR), and improve cell survival. It may therefore play a crucial role in neurodegenerative diseases like AD. However, only limited studies of sestrin2 and AD have been conducted up to now. In this article, we discuss current experimental evidence to demonstrate the potential roles of sestrin2 in treating neurodegenerative diseases, focusing specifically on AD. Strategies for augmenting sestrin2 expression may strengthen neurons, adapting them to stressful conditions through counteracting oxidative stress, and may also adjust the autophagy process, these two effects together conferring neuronal resistance in cases of AD.

Sestrin2 and Beclin1 levels in Polycystic Ovary Syndrome

Background

Sestrin2 and beclin1 are two newly found proteins that have essential roles in autophagy. This study attempted to evaluate the plasma concentrations of sestrin2 and beclin1 in women with polycystic ovary syndrome (PCOS) and healthy controls and to explore the clinical value of these proteins as novel biomarkers for PCOS.

Methods

In this case‐control study, plasma levels of sestrin2 and beclin1, fasting blood sugar (FBS), lipid profile, insulin, and androgens were evaluated in 63 women (31 patients and 32 controls). Sestrin2 and beclin1 levels were determined using enzyme‐linked immunosorbent assay (ELISA). Descriptive statistics, correlation coefficients, logistic regression, and ROC curve analyses were used in this study.

Results

Plasma sestrin2 levels of the subjects with PCOS (40.74 [24.39–257.70]) were significantly lower than those of healthy subjects (255.78 [25.46–528.66]; p‐value = 0.040). ROC curve analysis showed that a cutoff value of 420.5 ng/L had an appropriate sensitivity (83.87%) and specificity (46.88%) for discriminating individuals with and without PCOS, with the area under the curve (95% CI) of 0.648 (0.518 to 0.764), p = 0.036. There were no statistically significant differences between the two groups concerning plasma levels of beclin1, biochemical parameters, blood pressure, and anthropometric features.

Conclusion

Our findings highlight the dysregulation of sestrin2 as a marker of autophagy in PCOS and its potential usefulness as a novel biomarker for PCOS. Further research is needed to better understand the role of this protein in the pathophysiology of PCOS and its value as a diagnostic tool for the evaluation of PCOS patients.

Sestrin2 as a gatekeeper of cellular homeostasis: Physiological effects for the regulation of hypoxia-related diseases

Sestrin2 (SESN2) is a conserved stress‐inducible protein (also known as hypoxia‐inducible gene 95 (HI95)) that is induced under hypoxic conditions. SESN2 represses the production of reactive oxygen species (ROS) and provides cytoprotection against various noxious stimuli, including hypoxia, oxidative stress, endoplasmic reticulum (ER) stress and DNA damage. In recent years, the determination of the regulation and signalling mechanisms of SESN2 has increased our understanding of its role in the hypoxic response. SESN2 has well‐documented roles in hypoxia‐related diseases, making it a potential target for diagnosis and treatment. This review discusses the regulatory mechanisms of SESN2 and highlights the significance of SESN2 as a biomarker and therapeutic target in hypoxia‐related diseases, such as cancer, respiratory‐related diseases, cardiovascular diseases and cerebrovascular diseases.

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.

Sestrin2 maintains OXPHOS integrity to modulate cardiac substrate metabolism during ischemia and reperfusion

Sestrin2 (Sesn2) is a stress-inducible protein that declines with aging in the heart. We reported that rescue Sesn2 levels in aged mouse hearts through gene therapy improves the resistance of aged hearts to ischemia and reperfusion (I/R) insults. We hypothesize that Sesn2 as a scaffold protein maintains mitochondrial integrity to protect heart from ischemic injury during I/R. Young C57BL/6 J (3–6 months), aged C57BL/6 J (24–26 months), and young Sesn2 KO (3–6 months, C57BL/6 J background) mice were subjected to in vivo regional ischemia and reperfusion. The left ventricle was collected for transcriptomics, proteomics and metabolomics analysis. The results demonstrated that Sesn2 deficiency leads to aging-like cardiac diastolic dysfunction and intolerance to ischemia reperfusion stress. Seahorse analysis demonstrated that Sesn2 deficiency in aged and young Sesn2 KO versus young hearts lead to impaired mitochondrial respiration rate with defects in Complex I and Complex II activity. The Sesn2 targeted proteomics analysis revealed that Sesn2 plays a critical role in maintaining mitochondrial functional integrity through modulating mitochondria biosynthesis and assembling of oxidative phosphorylation (OXPHOS) complexes. The RNA-Seq data showed that alterations in the expression of mitochondrial compositional and functional genes and substrate metabolism related genes in young Sesn2 KO and aged versus young hearts. Further immunofluorescence and immunoprecipitation analysis demonstrated that Sesn2 is translocated into mitochondria and interacts with OXPHOS components to maintain mitochondrial integrity in response to I/R stress. Biochemical analysis revealed that Sesn2 is associated with citrate cycle components to modulate pyruvate dehydrogenase and isocitrate dehydrogenase activities during I/R stress. Thus, Sesn2 serves as a scaffold protein interacting with OXPHOS components to maintain mitochondrial integrity under I/R stress. Age-related downregulation of cardiac Sesn2 fragilizes mitochondrial functional integrity in response to ischemic stress.

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Ischemia reperfusion stress triggers Sesn2 accumulation in mitochondria.

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Sesn2 interacts with OXPHOS complexes to modulate the adaptive substrate metabolism.

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Age-related Sesn2 maintains mitochondrial functional integrity under stress conditions.

Sestrins in Physiological Stress Responses

Sestrins are a family of proteins that respond to a variety of environmental stresses, including genotoxic, oxidative, and nutritional stresses. Sestrins affect multiple signaling pathways: AMP-activated protein kinase, mammalian target of rapamycin complexes, insulin-AKT, and redox signaling pathways. By regulating these pathways, Sestrins are thought to help adapt to stressful environments and subsequently restore cell and tissue homeostasis. In this review, we describe how Sestrins mediate physiological stress responses in the context of nutritional and chemical stresses (liver), physical movement and exercise (skeletal muscle), and chemical, physical, and inflammatory injuries (heart). These findings also support the idea that Sestrins are a molecular mediator of hormesis, a paradoxical beneficial effect of low- or moderate-level stresses in living organisms.

Sestrin 2 controls the cardiovascular aging process via an integrated network of signaling pathways

As an inevitable biological process, cardiovascular aging is the greatest risk factor for cardiovascular diseases (CVDs). Sestrin 2 (Sesn2), a stress-inducible and age-related protein associated with various stress conditions, plays a pivotal role in slowing this process. It acts as an anti-aging agent, mainly through its antioxidant enzymatic activity and regulation of antioxidant signaling pathways, as well as by activating adenosine monophosphate-activated protein kinase and inhibiting mammalian target of rapamycin complex 1. In this review, we first introduce the biochemical functions of Sesn2 in the cardiovascular aging process, and describe how Sesn2 expression is regulated under various stress conditions. Next, we emphasize the role of Sesn2 signal transduction in a series of age-related CVDs, including hypertension, myocardial ischemia and reperfusion, atherosclerosis, and heart failure, as well as provide potential mechanisms for the association of Sesn2 with CVDs. Finally, we present the potential therapeutic applications of Sesn2-directed therapy and future prospects.

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.

Circulating Sestrin Levels Are Increased in Hypertension Patients

Background

Sestrins (Sesns), a group of oxidative stress-related proteins, have been reported to be involved in various cardiovascular diseases, including aortic dissection and chronic heart failure. This study is aimed at investigating the level of circulating Sesn1, Sesn2, and Sesn3 in hypertension patients.

Methods

Plasma levels of Sesn1, Sesn2, and Sesn3 in 400 hypertensive patients and 100 normotensive subjects were detected using enzyme-linked immunosorbent assay (ELISA) kits. The hypertension patients were divided into groups with grade I (n = 140), grade II (n = 180), and grade III (n = 80) hypertension.

Results

Compared with the normotensive subjects, Sesn1, Sesn2, and Sesn3 levels were increased in patients with hypertension, with a gradual increase between the groups with grade I, grade II, and grade III hypertension. Elevated Sesn1, Sesn2, and Sesn3 levels were positively correlated with both the systolic blood pressure (SBP) and diastolic blood pressure (DBP). Moreover, Sesn1, Sesn2, and Sesn3 levels were elevated in patients with dipper hypertension and further increased in patients with nondipper hypertension. In addition, smokers, as well as patients with higher levels of angiotensin II (Ang II) and carotid atherosclerotic plaque (CAP), exhibited increased Sesn1, Sesn2, and Sesn3 levels when compared with patients without these clinical characteristics. Furthermore, plasma levels of Sesn1, Sesn2, and Sesn3 were negatively correlated with the presence of CAP.

Conclusions

Circulating Sesn levels are increased in patients with hypertension and may be a target for the prevention and treatment of clinical hypertension.

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.

Plasma sestrin2 concentrations and carotid atherosclerosis

BACKGROUND

Sestrin2 is a stress-inducible antioxidant protein that plays a protective role against oxidative stress. However, blood sestrin2 concentrations in subjects with carotid atherosclerosis have not been elucidated.

METHODS

We investigated plasma sestrin2 concentrations in 152 subjects undergoing carotid ultrasonography. Plaque severity was evaluated as plaque score.

RESULTS

Of the 152 subjects, plaque was found in 63 (41%). Plasma sestrin2 concentrations were higher in 63 subjects with plaque than in 89 without plaque (median 14.1 vs. 12.8 ng/ml, P < 0.02). A stepwise increase in sestrin2 concentrations was found depending on plaque score: 12.8 ng/ml in score = 0 (n = 89), 12.7 ng/ml in score = 1 (n = 31), and 15.9 ng/ml in score ≥2 (n = 32)(P < 0.005). Especially, sestrin2 concentrations in subjects with score ≥ 2 were higher than in score = 0 and score = 1 (P < 0.05). Sestrin2 concentrations correlated with plaque score (r = 0.24, P < 0.005). In multivariate analysis, sestrin2 concentration was an independent factor associated with score ≥ 2. Odds ratio for score ≥ 2 was 5.70 (95%CI = 1.99-16.35) for high sestrin2 concentration (>13.0 ng/ml).

CONCLUSION

Plasma sestrin2 concentrations were found to be high in subjects with carotid plaque and to be associated with plaque severity. High plasma sestrin2 concentrations in subjects with carotid plaque may reflect a protective response against the progression of carotid atherosclerosis.

Sestrin2: Its Potential Role and Regulatory Mechanism in Host Immune Response in Diseases

Sestrin2 (SESN2), a highly evolutionarily conserved protein, is critically involved in cellular responses to various stresses. SESN2 has a protective effect on physiological and pathological states mainly via regulating oxidative stress, endoplasmic reticulum stress, autophagy, metabolism, and inflammation. In recent years, breakthrough investigations with regard to the regulation and signaling mechanisms of SESN2 have markedly deepened our understanding of its potential role as well as its significance in host response. However, the functions of SESN2 in the immune system and inflammation remain elusive. It has been documented that many immune cells positively express SESN2 and, in turn, that SESN2 might modulate cellular activities. This review incorporates recent progress and aims to provide novel insight into the protective role and regulatory pathway of SESN2, which acts as a potential biomarker and therapeutic target in the context of various diseases.