The sirtuin family in health and disease

Water extract of earthworms mitigates kidney injury triggered by oxidative stress via activating intrarenal Sirt1/Nrf2 cascade and ameliorating mitochondrial damage

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemia-reperfusion (IR) injury can result in acute renal failure. Oxidative stress is a major factor in IR-induced cell death in the kidneys. According to traditional Chinese medicine, earthworms (Pheretima aspergillum) can be used to treat various kidney diseases.

AIM OF THE STUDY

The present study was designed to understand the protective effects of the water extract of earthworms (WEE) against oxidative stress on the kidneys and the crucial molecular events associated with its nephroprotective activity.

MATERIALS AND METHODS

Cytotoxicity caused by H2O2 in HEK293, HK2, and primary mouse renal tubular epithelial cells (TECs) was used to investigate the effect of WEE on oxidative stress-induced renal injury in vitro. IR-induced kidney injury was established using rats as an in vivo model. The WEE-mediated protection of the kidneys against oxidative stress was compared with that of glutathione, a common antioxidant used as a positive control.

RESULTS

In HEK293 cells, HK2 cells, and primary mouse TECs, WEE relieved H2O2-induced mitochondrial damage, apoptosis, and ferroptosis. In kidney cells, WEE increased the expression of Sirt1, boosted LKB1 and AMPK phosphorylation, and upregulated nuclear Nrf2. Suppression of Sirt1 and LKB1 knock down abrogated WEE-induced protection against H2O2. WEE ameliorated IR-induced kidney injury and intrarenal inflammation in rats. In rat kidneys, WEE mitigated mitochondrial damage and suppressed IR-induced apoptosis and ferroptosis. Mechanistically, WEE increased Sirt1 expression, enhanced the phosphorylation of LKB1 and AMPK, and increased intranuclear Nrf2 levels in IR kidneys. IR treatment resulted in considerable increase in renal MDA levels and a prominent decrease in antioxidative enzyme activity. These lesions were significantly alleviated by WEE.

CONCLUSIONS

WEE mitigated H2O2-induced cytotoxicity in kidney cells in vitro and improved IR-induced kidney damage in rats. Mechanistically, WEE potentiated the Sirt1/Nrf2 axis and relieved mitochondrial damage in the kidney cells. These events inhibited the apoptosis and ferroptosis induced by oxidative stress. Our findings support the potential application of WEE for the clinical treatment of kidney diseases caused by intrarenal oxidative stress.

Histone deacetylases: Regulation of vascular homeostasis via endothelial cells and vascular smooth muscle cells and the role in vascular pathogenesis

Histone deacetylases (HDACs) are proteases that play a key role in chromosome structural modification and gene expression regulation, and the involvement of HDACs in cancer, the nervous system, and the metabolic and immune system has been well reviewed. Our understanding of the function of HDACs in the vascular system has recently progressed, and a significant variety of HDAC inhibitors have been shown to be effective in the treatment of vascular diseases. However, few reviews have focused on the role of HDACs in the vascular system. In this study, the role of HDACs in the regulation of the vascular system mainly involving endothelial cells and vascular smooth muscle cells was discussed based on recent updates, and the role of HDACs in different vascular pathogenesis was summarized as well. Furthermore, the therapeutic effects and prospects of HDAC inhibitors were also addressed in this review.

Role of oxidative stress in mitochondrial dysfunction and their implications in intervertebral disc degeneration: Mechanisms and therapeutic strategies

Background

Intervertebral disc degeneration (IVDD) is widely recognized as one of the leading causes of low back pain. Intervertebral disc cells are the main components of the intervertebral disc (IVD), and their functions include synthesizing and secreting collagen and proteoglycans to maintain the structural and functional stability of the IVD. In addition, IVD cells are involved in several physiological processes. They help maintain nutrient metabolism balance in the IVD. They also have antioxidant and anti-inflammatory effects. Because of these roles, IVD cells are crucial in IVDD. When IVD cells are subjected to oxidative stress, mitochondria may become damaged, affecting normal cell function and accelerating degenerative changes. Mitochondria are the energy source of the cell and regulate important intracellular processes. As a key site for redox reactions, excessive oxidative stress and reactive oxygen species can damage mitochondria, leading to inflammation, DNA damage, and apoptosis, thus accelerating disc degeneration.

Aim of review

Describes the core knowledge of IVDD and oxidative stress. Comprehensively examines the complex relationship and potential mechanistic pathways between oxidative stress, mitochondrial dysfunction and IVDD. Highlights potential therapeutic targets and frontier therapeutic concepts. Draws researchers' attention and discussion on the future research of all three.

Key scientific concepts of review

Origin, development and consequences of IVDD, molecular mechanisms of oxidative stress acting on mitochondria, mechanisms of oxidative stress damage to IVD cells, therapeutic potential of targeting mitochondria to alleviate oxidative stress in IVDD.

The translational potential of this article

Targeted therapeutic strategies for oxidative stress and mitochondrial dysfunction are particularly critical in the treatment of IVDD. Using antioxidants and specific mitochondrial therapeutic agents can help reduce symptoms and pain. This approach is expected to significantly improve the quality of life for patients. Individualized therapeutic approaches, on the other hand, are based on an in-depth assessment of the patient's degree of oxidative stress and mitochondrial functional status to develop a targeted treatment plan for more precise and effective IVDD management. Additionally, we suggest preventive measures like customized lifestyle changes and medications. These are based on understanding how IVDD develops. The aim is to slow down the disease and reduce the chances of it coming back. Actively promoting clinical trials and evaluating the safety and efficacy of new therapies helps translate cutting-edge treatment concepts into clinical practice. These measures not only improve patient outcomes and quality of life but also reduce the consumption of healthcare resources and the socio-economic burden, thus having a positive impact on the advancement of the IVDD treatment field.

LncRNA LINC01664 promotes cancer resistance through facilitating homologous recombination-mediated DNA repair

The intracellular responses to DNA double-strand breaks (DSB) repair are crucial for genomic stability and play an essential role in cancer resistance. In addition to canonical DSB repair proteins, long non-coding RNAs (lncRNAs) have been found to be involved in this sophisticated network. In the present study, we performed a loss-of-function screen for a customized siRNA Premix Library to identify lncRNAs that participate in homologous recombination (HR) process. Among the candidates, we identified LINC01664 as a novel lncRNA required for HR repair. Furthermore, LINC01664 knockdown significantly increased the sensitivity of cancer cells to DNA damage agents such as ionizing radiation and genotoxic drugs. Mechanistically, LINC01664 interacted with Sirt1 promoter and then activated Sirt1 transcription, which contributed to HR-mediated DNA damage repair. In summary, our findings revealed a new mechanism of LINC01664 in DNA damage repair, providing evidence for a potential therapeutic strategy for eliminating the treatment bottlenecks caused by cancer resistance to chemotherapy and radiotherapy.

SIRT1: A Potential Therapeutic Target for Coronary Heart Disease Combined with Anxiety or Depression

Coronary heart disease (CHD) combined with anxiety or depression is increasingly receiving attention in the clinical field of cardiology, and exploring the comorbidity pathological mechanisms of cardiovascular disease combined with psychological disorders is a hot research topic for scholars in this field. Current research suggests that Silent Information Regulatory Factor 1 (SIRT1) may serve as a potential biomarker for the comorbidity mechanism and treatment of CHD with anxiety or depression. SIRT1 is considered a promising therapeutic target for CHD combined with anxiety or depression, with the ability to regulate inflammatory cytokine levels, alleviate oxidative stress damage, activate multiple signaling pathways, reduce platelet hyperresponsiveness, and exert neuroprotective and cardioprotective effects. In this comprehensive review, we deeply studied the structure, function, and mechanism of SIRT1, and discussed its protective effects in the cardiovascular and nervous system. The latest progress in the mechanism of SIRT1's role in CHD combined with anxiety or depression was emphasized, including its specific mechanisms in regulating inflammatory response, alleviating oxidative stress, and mediating various signaling pathways. In addition, this article also summarizes the therapeutic potential of SIRT1 as a potential biomarker in patients with CHD combined with anxiety or depression.

Mitochondrial Dysfunction-Molecular Mechanisms and Potential Treatment approaches of Hepatocellular Carcinoma

Primary liver cancer (PLC), also known as hepatocellular carcinoma (HCC), is a common type of malignant tumor of the digestive system. Its pathological form has a significant negative impact on the patients' quality of life and ability to work, as well as a significant financial burden on society. Current researches had identified chronic hepatitis B virus infection, aflatoxin B1 exposure, and metabolic dysfunction-associated steatotic liver disease (MASLD) as the main causative factors of HCC. Numerous variables, including inflammatory ones, oxidative stress, apoptosis, autophagy, and others, have been linked to the pathophysiology of HCC. On the other hand, autoimmune regulation, inflammatory response, senescence of the hepatocytes, and mitochondrial dysfunction are all closely related to the pathogenesis of HCC. In fact, a growing number of studies have suggested that mitochondrial dysfunction in hepatocytes may be a key factor in the pathogenesis of HCC. In disorders linked to cancer, mitochondrial dysfunction has gained attention in recent 10 years. As the primary producer of adenosine triphosphate (ATP) in liver cells, mitochondria are essential for preserving cell viability and physiological processes. By influencing multiple pathological processes, including mitochondrial fission/fusion, mitophagy, cellular senescence, and cell death, mitochondrial dysfunction contributes to the development of HCC. We review the molecular mechanisms of HCC-associated mitochondrial dysfunction and discuss new directions for quality control of mitochondrial disorders as a treatment for HCC.

Glycolysis: A multifaceted metabolic pathway and signalling hub

Glycolysis is a highly conserved metabolic pathway responsible for the anaerobic production of adenosine triphosphate (ATP) from the breakdown of glucose molecules. While serving as a primary metabolic pathway in prokaryotes, glycolysis is also utilised by respiring eukaryotic cells, providing pyruvate to fuel oxidative metabolism. Furthermore, glycolysis is the primary source of ATP production in multiple cellular states (e.g. hypoxia) and is particularly important in maintaining bioenergetic homeostasis in the most abundant cell type in the human body, the erythrocyte. Beyond its role in ATP production, glycolysis also functions as a signalling hub, producing several metabolic intermediates which serve roles in both signalling and metabolic processes. These signals emanating from the glycolytic pathway can profoundly impact cell function, phenotype and fate, and have previously been overlooked. In this review, we will discuss the role of the glycolytic pathway as a source of signalling molecules in eukaryotic cells, emphasising the newfound recognition of glycolysis' multifaceted nature and its importance in maintaining cellular homeostasis, beyond its traditional role in ATP synthesis.

Supplemental Oxygen Alters the Pentose Phosphate Pathway in the Developing Mouse Brain Through SIRT Signaling

Oxygen support plays a critical role in the management of preterm infants in neonatal intensive care units. On the other hand, the possible effects of oxygen supplementation on cellular functions, specifically glucose metabolism, have been less understood. PURPOSE: of the study is to investigate whether supplemental oxygen alters glucose metabolism and pentose phosphate pathway (PPP) activity in the brain tissue and its relevance with silent information regulator proteins (SIRT) pathway. For this purpose, newborn C57BL/6 pups were exposed to 90% oxygen from birth until postnatal day 7 (PN7) and metabolites of glysolysis and PPP were investigated through metabolomics analysis. SIRT1, glucose-6-phosphate dehydrogenase (G6PD) and transaldolase (TALDO) proteins were examined immunohistochemically and molecularly in the prefrontal and hippocampus regions of the brain. Later on, SIRT1 inhibition was carried out. Our results indicate that supplemental oxygen causes an increase in PPP metabolites as well as activation of G6PD enzyme in the brain tissue, which is reversed by SIRT1 inhibition. Our study underlines a connection between supplemental oxygen, glucose metabolism, PPP pathway and the SIRT signaling. Understanding these intricate relationships not only deepens our knowledge of cellular physiology but also holds promise for therapeutic interventions for creating neuroprotective strategies in preterm brain.

Pleiotropic Effects of Resveratrol on Aging-Related Cardiovascular Diseases-What Can We Learn from Research in Dogs?

Resveratrol (RES) is a polyphenol with natural anti-inflammatory and antioxidant properties. It is found in abundance in plants, i.e., grapes and mulberry fruit. In addition, synthetic forms of RES exist. Since the discovery of its specific biological properties, RES has emerged as a candidate substance not only with modeling effects on the immune response but also as an important factor in preventing the onset and progression of cardiovascular disease (CVD). Previous research provided strong evidence of the effects of RES on platelets, mitochondria, cardiomyocytes, and vascular endothelial function. In addition, RES positively affects the coagulation system and vasodilatory function and improves blood flow. Not only in humans but also in veterinary medicine, cardiovascular diseases have one of the highest incidence rates. Canine and human species co-evolved and share recent evolutionary selection processes, and interestingly, numerous pathologies of companion dogs have a human counterpart. Knowledge of the impact of RES on the cardiovascular system of dogs is becoming clearer in the literature. Dogs have long been recognized as valuable animal models for the study of various human diseases as they share many physiological and genetic similarities with humans. In this review, we aim to shed light on the pleiotropic effects of resveratrol on cardiovascular health in dogs as a translational model for human cardiovascular diseases.

Sirtuin 1/sirtuin 3 are robust lysine delactylases and sirtuin 1-mediated delactylation regulates glycolysis

Lysine lactylation (Kla), an epigenetic mark triggered by lactate during glycolysis, including the Warburg effect, bridges metabolism and gene regulation. Enzymes such as p300 and HDAC1/3 have been pivotal in deciphering the regulatory dynamics of Kla, though questions about additional regulatory enzymes, their specific Kla substrates, and the underlying functional mechanisms persist. Here, we identify SIRT1 and SIRT3 as key "erasers" of Kla, shedding light on their selective regulation of both histone and non-histone proteins. Proteomic analysis in SIRT1/SIRT3 knockout HepG2 cells reveals distinct substrate specificities toward Kla, highlighting their unique roles in cellular signaling. Notably, we highlight the role of specific Kla modifications, such as those on the M2 splice isoform of pyruvate kinase (PKM2), in modulating metabolic pathways and cell proliferation, thereby expanding Kla's recognized functions beyond epigenetics. Therefore, this study deepens our understanding of Kla's functional mechanisms and broadens its biological significance.

Elucidating the Unconventional Binding Mode of a DNA-Encoded Library Hit Provides a Blueprint for Sirtuin 6 Inhibitor Development

Sirtuin 6 (Sirt6), an NAD+-dependent deacylase, has emerged as a promising target for aging-related diseases and cancer. Advancing the medicinal chemistry of Sirt6 modulators is crucial for the development of chemical probes aimed at unraveling the intricate biological functions of Sirt6 and unlocking its therapeutic potential. A proprietary DNA-encoded library yielded Sirt6 inhibitor 2-Pr, displaying remarkable inhibitory activity and isoform-selectivity, and featuring a chemical structure distinct from reported Sirt6 modulators. In this study, we explore the inhibitory mechanism of 2-Pr, evaluating the impact of chemical modifications and presenting a crystal structure of the Sirt6/ADP-ribose/2-Pr complex. Notably, co-crystal structure analysis reveals an unexpected and unprecedented binding mode of Sirt6, with 2-Pr spanning the acyl channel of the enzyme, extending into the acetyl-lysine binding pocket, and reaching toward the C-site. This unique binding mode guides potential avenues for developing potent and selective Sirt6 inhibitors.

SIRT7 remodels the cytoskeleton via RAC1 to enhance host resistance to Mycobacterium tuberculosis

Phagocytosis of Mycobacterium tuberculosis (Mtb) followed by its integration into the matured lysosome is critical in the host defense against tuberculosis. How Mtb escapes this immune attack remains elusive. In this study, we unveiled a novel regulatory mechanism by which SIRT7 regulates cytoskeletal remodeling by modulating RAC1 activation. We discovered that SIRT7 expression was significantly reduced in CD14+ monocytes of TB patients. Mtb infection diminished SIRT7 expression by macrophages at both the mRNA and protein levels. SIRT7 deficiency impaired actin cytoskeleton-dependent macrophage phagocytosis, LC3II expression, and bactericidal activity. In a murine tuberculosis model, SIRT7 deficiency detrimentally impacted host resistance to Mtb, while Sirt7 overexpression significantly increased the host defense against Mtb, as determined by bacterial burden and inflammatory-histopathological damage in the lung. Mechanistically, we demonstrated that SIRT7 limits Mtb infection by directly interacting with and activating RAC1, through which cytoskeletal remodeling is modulated. Therefore, we concluded that SIRT7, in its role regulating cytoskeletal remodeling through RAC1, is critical for host responses during Mtb infection and proposes a potential target for tuberculosis treatment.IMPORTANCETuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a significant global health issue. Critical to macrophages' defense against Mtb is phagocytosis, governed by the actin cytoskeleton. Previous research has revealed that Mtb manipulates and disrupts the host's actin network, though the specific mechanisms have been elusive. Our study identifies a pivotal role for SIRT7 in this context: Mtb infection leads to reduced SIRT7 expression, which, in turn, diminishes RAC1 activation and consequently impairs actin-dependent phagocytosis. The significance of our research is that SIRT7 directly engages with and activates Rac Family Small GTPase 1 (RAC1), thus promoting effective phagocytosis and the elimination of Mtb. This insight into the dynamic between host and pathogen in TB not only broadens our understanding but also opens new avenues for therapeutic development.

Gut aging: A wane from the normal to repercussion and gerotherapeutic strategies

Globally, age-related diseases represent a significant public health concern among the elderly population. In aging, healthy organs and tissues undergo structural and functional changes that put the aged adults at risk of diseases. Some of the age-related diseases include cancer, atherosclerosis, brain disorders, muscle atrophy (sarcopenia), gastrointestinal (GIT) disorders, etc. In organs, a decline in stem cell function is the starting point of many conditions and is extremely important in GIT disorder development. Many studies have established that aging affects stem cells and their surrounding supportive niche components. Although there is a significant advancement in treating intestinal aging, the rising elderly population coupled with a higher occurrence of chronic gut ailments necessitates more effective therapeutic approaches to preserve gut health. Notable therapeutic strategies such as Western medicine, traditional Chinese medicine, and other health-promotion interventions have been reported in several studies to hold promise in mitigating age-related gut disorders. This review highlights findings across various facets of gut aging with a focus on aging-associated changes of intestinal stem cells and their niche components, thus a deviation from the normal to repercussion, as well as essential therapeutic strategies to mitigate intestinal aging.

Discovery of Novel Thiazole-Based SIRT2 Inhibitors as Anticancer Agents: Molecular Modeling, Chemical Synthesis and Biological Assays

The search and development of effective sirtuin small molecule inhibitors (SIRTIs) continues to draw great attention due to their wide range of pharmacological applications. Based on SIRTs' involvement in different biological pathways, their ligands were investigated for many diseases, such as cancer, neurodegenerative disorders, diabetes, cardiovascular diseases and autoimmune diseases. The elucidation of a substantial number of SIRT2-ligand complexes is steering the identification of novel and more selective modulators. Among them, SIRT2 in the presence of the SirReal2 analog series was the most studied. On this basis, we recently reported structure-based analyses leading to the discovery of thiazole-based compounds acting as SIRT2 inhibitors (T1, SIRT2 IC50 = 17.3 µM). Herein, ligand-based approaches followed by molecular docking simulations allowed us to evaluate in silico a novel small series of thiazoles (3a-3d and 5a, 5d) as putative SIRT2 inhibitors. Results from the computational studies revealed comparable molecular interaction fields (MIFs) and docking positionings of most of these compounds with respect to reference SIRT2Is. Biochemical and biological assays validated this study and pointed to compound 5a (SIRT2 IC50 = 9.0 µM) as the most interesting SIRT2I that was worthy of further development as an anticancer agent.

Targeting sirtuins for cancer therapy: epigenetics modifications and beyond

Sirtuins (SIRTs) are well-known as nicotinic adenine dinucleotide+(NAD+)-dependent histone deacetylases, which are important epigenetic enzymes consisting of seven family members (SIRT1-7). Of note, SIRT1 and SIRT2 are distributed in the nucleus and cytoplasm, while SIRT3, SIRT4 and SIRT5 are localized in the mitochondria. SIRT6 and SIRT7 are distributed in the nucleus. SIRTs catalyze the deacetylation of various substrate proteins, thereby modulating numerous biological processes, including transcription, DNA repair and genome stability, metabolism, and signal transduction. Notably, accumulating evidence has recently underscored the multi-faceted roles of SIRTs in both the suppression and progression of various types of human cancers. Crucially, SIRTs have been emerging as promising therapeutic targets for cancer therapy. Thus, in this review, we not only present an overview of the molecular structure and function of SIRTs, but elucidate their intricate associations with oncogenesis. Additionally, we discuss the current landscape of small-molecule activators and inhibitors targeting SIRTs in the contexts of cancer and further elaborate their combination therapies, especially highlighting their prospective utility for future cancer drug development.

Sirt4 Overexpression Modulates the JAK2/STAT3 and PI3K/AKT/mTOR Axes to Alleviate Sepsis-Induced Acute Lung Injury

BACKGROUND

Sepsis-induced acute lung injury (ALI) is a severe organ dysfunction characterized by lung inflammation and apoptosis. The mechanisms underlying sepsis-induced ALI remain poorly understood. Here, we determined the effects of sirtuin 4 (SIRT4) on sepsis-induced ALI.

METHODS

Lipopolysaccharide (LPS)-induced injury cell and cecal ligation and puncture (CLP) animal models were established. Overexpression vectors and lentiviral transfections were used to upregulate SIRT4 expression. Lung cell apoptosis, inflammation, and the levels of associated factors were evaluated. Changes in the PI3K/AKT/mTOR and JAK2/STAT3 pathways were measured, and their potential involvement was examined using LY294002 (PI3K inhibitor), 740 Y-P (PI3K agonist), AG490 (JAK2 inhibitor), and coumermycin A1 (JAK2 agonist).

RESULTS

Lower SIRT4 expression was observed in LPS-exposed A549 cells and CLP rats. In LPS-induced A549 cells, Sirt4 overexpression enhanced cell viability, resisted apoptosis, restored the expression of apoptosis-associated proteins (HMB1, cleaved CASP3, BAX, and BCL), and reduced the secretion of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α). In CLP rats, Sirt4 overexpression prolonged survival time, alleviated lung histopathological damage, reduced pulmonary edema, mitigated lung infection, decreased lung apoptosis, and lowered serum levels of inflammatory cytokines. Furthermore, Sirt4 overexpression blocked JAK2/STAT3/AKT/mTOR phosphorylation. 740 Y-P and coumermycin A1 reversed the protective effects of Sirt4 overexpression in LPS-treated A549 cells, resulting in decreased cell viability and increased apoptosis. LY294002 and AG490 enhanced the protective effects of Sirt4 overexpression in LPS-treated A549 cells.

CONCLUSION

SIRT4 alleviates sepsis-induced ALI by inhibiting JAK2/STAT3/PI3K/AKT/mTOR signaling. Upregulating SIRT4 expression may serve as an innovative therapeutic approach for lung injury management in sepsis.

Discovery of SIRT1-Activating Hydrogen Sulfide Donating Derivatives for Efficient Resistant of Myocardial Ischemic Injury

Activating SIRT1 or promoting SIRT1 expression are both protective against myocardial ischemia. Combining these approaches would be an effective strategy for treating ischemic heart disease. Herein, we identified lead compounds with SIRT1 activation activity through screening the natural product library, and five series of H2S donating derivatives were designed and synthesized. Among them, compound 17 exerted an effective cardioprotective effect in vitro and in vivo. The addition of H2S scavenger attenuated the protective activity, emphasizing the critical involvement of H2S in the myocardial ischemia process. Interestingly, 17 exhibited stronger direct SIRT1 activative ability and induced higher SIRT1 expression capability compared to the lead. Furthermore, 17 attenuates oxidative stress-induced cardiomyocytes apoptosis by activating the SIRT1-PGC1α signaling pathway. Our study validated the promising potential of activating SIRT1 and promoting SIRT1 expression through H2S to improve cardiomyocytes function, providing novel insights into the protective mechanisms during the progression of ischemic heart disease.

Lidocaine inhibits the lung cancer progression through decreasing the HIST1H2BL levels via SIRT5 mediated succinylation

Lung cancer is a malignant tumor originating from the bronchial mucosa or gland of the lung. Recently, lidocaine, a widely used amide local anesthetic, was demonstrated to inhibit many cancer progression. This research was performed to explore the specific mechanism of lidocaine in the lung cancer progression. The human normal lung epithelial cells (BEAS-2B), and NSCLC cell lines (A549 and H1299) were used and treated with lidocaine in this study. The cell biological behaviors were detected by CCK-8, wound healing and transwell assay. Besides, the mRNA and protein levels of related genes were detected by western blot. The results showed that lidocaine treatment significantly decreased the cell viability and migration of the A549 and H1299 cells. Furthermore, the lidocaine treatment significantly decreased the succinylation and protein levels of HIST1H2BL, which was reversed after SIRT5 knockdown. Additionally, HIST1H2BL knockdown decreased the cell viability and migration of the A549 and H1299 cells, while HIST1H2BL overexpression reversed the effects of lidocaine on the cell viability and migration of the A549 and H1299 cells. In conclusion, lidocaine treatment might inhibited the lung cancer progression through decreasing the SIRT5 mediated succinylation of HIST1H2BL.

The role of Klotho and sirtuins in sleep-related cardiovascular diseases: a review study

The prevalence of sleep disorders has been reported from 1.6% to 56.0%, worldwide. Sleep deprivation causes cardiovascular diseases (CVDs) including atherosclerosis, vascular aging, hypertension, heart dysfunction, reduced heart rate variability, and cardiac arrhythmia. Reduced tissue oxygen causes various CVDs by activating pro-inflammatory factors and increasing oxidative stress. Sleep disorders are more important and prevalent in older people and cause more severe cardiovascular complications. On the other hand, the reduction of Klotho level, an age-dependent protein whose expression decreases with age, is associated with age-related diseases. Sirtuins, class III histone deacetylases, also are among the essential factors in postponing cellular aging and increasing the lifespan of organisms, and they do this by regulating different pathways in the cell. Sirtuins and Klotho play an important role in the pathophysiology of CVDS and both have anti-oxidative stress and anti-inflammatory activity. Studies have shown that the levels of Klotho and sirtuins are altered in sleep disorders. In this article, alterations of Klotho and sirtuins in sleep disorders and in the development of sleep-related CVDs were reviewed and the possible signaling pathways were discussed. The inclusion criteria were studies with keywords of different types of sleep disorders and CVDs, klotho, SIRT1-7, and sirtuins in PubMed, Scopus, Embase، Science Direct، Web of Sciences and Google Scholar by the end of 2023. The studies revealed there is a bidirectional relationship between sleep disorders and the serum and tissue levels of Klotho and sirtuins and sleep related-CVDs.

The role of histone deacetylases in inflammatory respiratory diseases: an update

INTRODUCTION

Histone deacetylases (HDACs) catalyze the removal of acetyl groups from lysine residues of histones and other proteins, generally leading to a closed chromosomal configuration and transcriptional repression. Different HDACs have distinct substrate specificities and functions in different biological processes. Accumulating evidence indicates that HDACs play a key role in the pathogenesis of multiple respiratory diseases.

AREAS COVERED

After an extensive search of the PubMed database, Web of Science and ClinicalTrials.gov, covering the period from 1992 to 2024, this review summarizes recent advances in understanding the role of HDACs in inflammatory respiratory diseases, including allergic rhinitis (AR), chronic rhinosinusitis (CRS), asthma and chronic obstructive pulmonary disease (COPD). We also examine recent progress on the efficacy and potential use of histone deacetylase inhibitors (HDACi) for the treatment of these diseases.

EXPERT OPINION

Available data indicate that HDACs play an important role in the development of common inflammatory respiratory diseases, and HDACi have shown promise as treatments for these diseases. However, the exact roles and underlying mechanisms of specific HDACs in disease pathogenesis require further study. Additional work is necessary to develop novel potent HDACi with high isoform selectivity.

Identification of phytoestrogens as sirtuin inhibitor against breast cancer: Multitargeted approach

Despite progress in diagnosis and treatment strategies, breast cancer remains a primary risk to female health as indicated by second most cancer-deaths globally caused by this cancer. High risk mutation is linked to prognosis of breast cancer. Due to high resistance of breast cancer against current therapies, there is necessity of novel treatment strategies. Sirtuins are signaling proteins belonging to histone deacetylase class III family, known to control several cellular processes. Therefore, targeting sirtuins could be one of the approaches to treat breast cancer. Several plants synthesize phytoestrogens which exhibit structural and physiological similarities to estrogens and have been recognized to possess anticancer activity. In our study, we investigated several phytoestrogens for sirtuin inhibition by conducting molecular docking studies, and in-vitro studies against breast cancer cell lines. In molecular docking studies, we identified coumestrol possessing high binding energy with sirtuin proteins 1-3 as compared to other phytoestrogens. The molecular dynamic studies showed stable interaction of ligand and protein with higher affinity at sirtuin proteins 1-3 binding sites. In cell proliferation assay and colony formation assay using breast cancer cell lines (MCF-7 and MDAMB-231) coumestrol caused significant reduction in cell proliferation and number of colonies formed. Further, the flow cytometric analysis showed that coumestrol induces intracellular reactive oxygen species and the western blot analysis revealed reduction in the level of SIRT-1 expression in breast cancer cell lines. In conclusion, in-silico data and in-vitro studies suggest that the phytoestrogen coumestrol has sirtuin inhibitory activity against breast cancer.

Role of sirtuins in sepsis and sepsis-induced organ dysfunction: A review

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis causes a high mortality rate and current treatment focuses on supportive therapies but lacks specific therapeutic targets. Notably, sirtuins (SIRTs) shows potential clinical application in the treatment of sepsis. It has been demonstrated that SIRTs, the nicotinamide adenine dinucleotide+(NAD+)-dependent deacetylases that regulate key signaling pathways in eukaryotes and prokaryotes, are involved in a variety of biological processes. To date, seven mammalian yeast Sir2 homologs have been identified. SIRTs can regulate inflammation, oxidative stress, apoptosis, autophagy, and other pathways that play important roles in sepsis-induced organ dysfunction. However, the existing studies on SIRTs in sepsis are too scattered, and there is no relevant literature to integrate them. This review innovatively summarizes the different mechanisms of SIRTs in sepsis organ dysfunction according to the different systems, and focuses on SIRT agonists, inhibitors, and targeted drugs that have been proved to be effective in the treatment of sepsis, so as to integrate the clinical research and basic research closely. We searched PubMed for all literature related to SIRTs and sepsis since its inception using the following medical subject headings: sirtuins, SIRTs, and sepsis. Data on the mechanisms of SIRTs in sepsis-induced organ damage and their potential as targets for disease treatment were extracted.

Emerging role of sirtuins in non‑small cell lung cancer (Review)

Non‑small cell lung cancer (NSCLC) is a highly prevalent lung malignancy characterized by insidious onset, rapid progression and advanced stage at the time of diagnosis, making radical surgery impossible. Sirtuin (SIRT) is a histone deacetylase that relies on NAD+ for its function, regulating the aging process through modifications in protein activity and stability. It is intricately linked to various processes, including glycolipid metabolism, inflammation, lifespan regulation, tumor formation and stress response. An increasing number of studies indicate that SIRTs significantly contribute to the progression of NSCLC by regulating pathophysiological processes such as energy metabolism, autophagy and apoptosis in tumor cells through the deacetylation of histones or non‑histone proteins. The present review elaborates on the roles of different SIRTs and their mechanisms in NSCLC, while also summarizing novel therapeutic agents based on SIRTs. It aims to present new ideas and a theoretical basis for NSCLC treatment.

Protective Effects of Berberine on Nonalcoholic Fatty Liver Disease in db/db Mice via AMPK/SIRT1 Pathway Activation

OBJECTIVE

Berberine (BBR) has emerged as a promising therapeutic agent for nonalcoholic fatty liver disease (NAFLD). This study aims to elucidate the underlying molecular mechanisms.

METHODS

In this study, db/db mice were chosen as an animal model for NAFLD. A total of 10 healthy C57BL/6J mice and 30 db/db mice were randomly allocated to one of 4 groups: the normal control (NC) group, the diabetic control (DC) group, the Metformin (MET) therapy group, and the BBR therapy group. The total cholesterol (TC), triacylglycerol (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the serum were measured. The glutathione peroxidase (GSH-Px), glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), interleukin (IL)-1β, tumor necrosis factor (TNF)-α and monocyte chemotactic protein 1 (MCP-1) levels in liver tissue were measured. Hematoxylin and eosin (H&E), acid-Schiff (PAS) and TUNEL stanning was performed for histopathological analysis. Western blotting and immunohistochemistry were conducted to detect the expression levels of key proteins in the AMPK/SIRT1 pathway.

RESULTS

BBR could improve lipid metabolism, attenuate hepatic steatosis and alleviate liver injury significantly. The excessive oxidative stress, high levels of inflammation and abnormal apoptosis in db/db mice were reversed after BBR intervention. BBR clearly changed the expression of AMP-activated protein kinase (AMPK)/Sirtuin 1 (SIRT1), and their downstream proteins.

CONCLUSION

BBR could reverse NAFLD-related liver injury, likely by activating the AMPK/SIRT1 signaling pathway to inhibit oxidative stress, inflammation and apoptosis in hepatic tissue.

Histone Deacetylase Inhibitors for Peripheral T-Cell Lymphomas

Histone deacetylase inhibitors (HDACis) are being recognized as a potentially effective treatment approach for peripheral T-cell lymphomas (PTCLs), a heterogeneous group of aggressive malignancies with an unfavorable prognosis. Recent evidence has shown that HDACis are effective in treating PTCL, especially in cases where the disease has relapsed or is resistant to conventional treatments. Several clinical trials have demonstrated that HDACis, such as romidepsin and belinostat, can elicit long-lasting positive outcomes in individuals with PTCLs, either when used alone or in conjunction with conventional chemotherapy. They exert their anti-tumor effects by regulating gene expression through the inhibition of histone deacetylases, which leads to cell cycle arrest, induction of programmed cell death, and,the transformation of cancerous T cells, as demonstrated by gene expression profile studies. Importantly, besides clinical trials, real-world evidence indicated that the utilization of HDACis presents a significant and beneficial treatment choice for PTCLs. However, although HDACis showed potential effectiveness, they could not cure most patients. Therefore, new combinations with conventional drugs as well as new targeted agents are under investigation.

Genetic Background of Medication-Related Osteonecrosis of the Jaw: Current Evidence and Future Perspectives

Medication-related osteonecrosis of the jaw (MRONJ) is a rare side effect of antiresorptive drugs that significantly hinders the quality of life of affected patients. The disease develops in the presence of a combination of factors. Important pathogenetic factors include inflammation, inhibition of bone remodeling, or genetic predisposition. Since the first description of this rare side effect in 2003, a growing body of data has suggested a possible role for genetic factors in the disease. Several genes have been suggested to play an important role in the pathogenesis of MRONJ such as SIRT1, VEGFA, and CYP2C8. With the development of molecular biology, newer methods such as miRNA and gene expression studies have been introduced in MRONJ, in addition to methods that can examine the base sequence of the DNA. Describing the complex genetic background of MRONJ can help further understand its pathophysiology as well as identify new therapeutic targets to better manage this adverse drug reaction.

Symmetrical 2,7-disubstituted 9H-fluoren-9-one as a novel and promising scaffold for selective targeting of SIRT2

Sirtuin 2 (SIRT2) belongs to the family of silent information regulators (sirtuins), which comprises nicotinamide adenine dinucleotide (NAD+)-dependent protein lysine deacetylases. With a distribution across numerous tissues and organs of the human body, SIRT2 is involved in a wide range of physiological and pathological processes, such as regulating the cell cycle, energy metabolism, DNA repair, and tumorigenesis. Aberrant expression of SIRT2 has been closely associated with particular etiologies of human diseases, positioning SIRT2 as a promising therapeutic target. Herein, we detail the design overview and findings of novel symmetrical 2,7-disubstituted 9H-fluoren-9-one derivatives targeting SIRT2. SG3 displayed the most potent SIRT2-selective inhibitory profile, with an IC50 value of 1.95 μ M $\mu {\rm{M}}$ , and reduced the cell viability of human breast cancer MCF-7 cells accompanied by hyperacetylation of α-tubulin. Finally, molecular docking, molecular dynamics simulations, and binding free energy calculations using molecular mechanics/generalized born surface area method were performed to verify the binding ability of SG3 to SIRT2. Taken together, these results could enhance our understanding of the structural elements necessary for inhibiting SIRT2 and shed light on the mechanism of inhibition.

A preliminary study of sirtuin-1 on angiotensin II-induced senescence and inflammation in abdominal aortic aneurysms

Objective

Recent evidence suggests the involvement of senescence and inflammation in abdominal aortic aneurysm (AAA). Considering the role of sirtuin-1 (SIRT1) in delaying senescence, we aimed to preliminarily investigate the potential mechanism underlying the effects of SIRT1 in senescence and inflammation during AAA.

Material and Methods

A cell AAA model was established using angiotensin II (Ang II) as the inducer, which was applied to treat human aortic vascular smooth muscle cells (HASMCs). The senescence and cell cycle of treated HASMCs were evaluated based on senescence-associated (SA)-b-galactosidase (b-gal) assay and flow cytometry, respectively. The levels of inflammatory cytokines and proteins related to senescence-associated secretory phenotype (SASP), along with nuclear factor-kappa B (NF-kB) and mitogen-activated protein kinases (MAPK) pathways, as well as SIRT1, were gauged. The correlation between SIRT1 and NF-kB and MAPK pathway-related proteins was further estimated.

Results

In Ang II-treated HASMCs, reduced SIRT1 and B-cell lymphoma-2 levels yet increased levels of SASP-related proteins P16 and P21, inflammatory cytokines, as well as Bax and caspases were all visible. In the meantime, Ang II exposure enhanced the number of b-gal-positive HASMCs and promoted cell cycle arrest. SIRT1 was also repressed following Ang II treatment and negatively correlated with NF-kB and MAPK pathway-related proteins (P < 0.05). Furthermore, the overexpression of SIRT1 diminished the levels of SASP-related proteins and reduced the phosphorylation of extracellular regulated kinase 1/2 and P65 in Ang II-treated HASMCs (P < 0.05).

Conclusion

Taken together, our results indicate that SIRT1 overexpression attenuates the inflammatory and senescent responses of HASMCs in the Ang II-induced AAA cell model. This finding suggests that SIRT1 can be a highly promising target for clinical treatment of AAA.

Oral administration of astilbin mitigates acetaminophen-induced acute liver injury in mice by modulating the gut microbiota

Acetaminophen (APAP) overdose-induced acute liver injury (ALI) is characterized by extensive oxidative stress, and the clinical interventions for this adverse effect remain limited. Astilbin is an active compound found in the rhizome of Smilax glabra Roxb. with anti-inflammatory and antioxidant activities. Due to its low oral bioavailability, astilbin can accumulate in the intestine, which provides a basis for the interaction between astilbin and gut microbiota (GM). In the present study we investigated the protective effects of astilbin against APAP-induced ALI by focusing on the interaction between astilbin and GM. Mice were treated with astilbin (50 mg·kg-1·d-1, i.g.) for 7 days. After the last administration of astilbin for 2 h, the mice received APAP (300 mg/kg, i.g.) to induce ALI. We showed that oral administration of astilbin significantly alleviated APAP-induced ALI by altering the composition of GM and enriching beneficial metabolites including hydroxytyrosol (HT). GM depletion using an "antibiotics cocktail" or paraoral administration of astilbin abolished the hepatoprotective effects of astilbin. On the other hand, administration of HT (10 mg/kg, i.g.) caused similar protective effects in APAP-induced ALI mice. Transcriptomic analysis of the liver tissue revealed that HT inhibited reactive oxygen species and inflammation-related signaling in APAP-induced ALI; HT promoted activation of the Nrf2 signaling pathway to combat oxidative stress following APAP challenge in a sirtuin-6-dependent manner. These results highlight that oral astilbin ameliorates APAP-induced ALI by manipulating the GM and metabolites towards a more favorable profile, and provide an alternative therapeutic strategy for alleviating APAP-induced ALI.

Niacin regulates glucose metabolism and osteogenic differentiation via the SIRT2-C/EBPβ-AREG signaling axis

The pathogenesis of osteoporosis is driven by several mechanisms including the imbalance between osteoblastic bone formation and osteoclastic bone resorption. Currently, the role of Niacin (NA), also known as vitamin B3, in the regulation of osteoblastic differentiation is not fully understood. Data from the NHANES database were employed to investigate the association of NA intake with the prevalence of osteoporosis. Alterations in mRNA and protein levels of genes and proteins involved in osteogenic differentiation were evaluated via techniques including qRT-PCR, protein immunoblotting, Alkaline Phosphatase (ALP) activity analysis, ALP staining, and Alizarin Red staining. Changes in the mouse skeletal system were investigated by organizational analysis and Micro-CT. The results indicated that NA promoted osteogenic differentiation. Co-immunoprecipitation and chromatin immunoprecipitation were performed to explore the underlying mechanisms. It was observed that NA promoted AREG expression by deacetylating C/EBPβ via SIRT2, thereby activating the PI3K-AKT signaling pathway. It also enhanced the activity of the pivotal glycolytic enzyme, PFKFB3. This cascade amplified osteoblast glycolysis, facilitating osteoblast differentiation. These findings demonstrate that NA modulates glucose metabolism and influences osteogenic differentiation via the SIRT2-C/EBPβ-AREG pathway, suggesting that NA may be a potential therapeutic agent for the management of osteoporosis, and AREG could be a plausible target.

SIRT7 protects against liver fibrosis by suppressing stellate cell activation via TGF-β/SMAD2/3 pathway

BACKGROUND

SIRT7 is a class III HDACs deacetylase which plays critical roles in various biological processes. Aberrant SIRT7 expression is associated with tumorigenesis and disease progression while role of SIRT7 in hepatic fibrosis remain elusive.

METHODS

SIRT7 expression was examined in fibrotic liver sample via WB and IHC. Myeloid cell-specific knockout (SIRT7MKO) mice were generated by crossing SIRT7flox/flox mice with LysM-Cre mice. Primary hepatic stellate cells (HSCs) was isolated to examine stellate cells activation. SIRT7 and SMAD2/3 interaction were analyzed by immunoprecipitation. SB525334 was used to prevent SMAD2/3 phosphorylation.

RESULTS

SIRT7 expression was decreased during chronic liver disease progression but was increased in liver cancer. IHC staining indicated that SIRT7 was primarily expressed in non-parenchymal cells in both fibrotic and cirrhotic liver. Knockout SIRT7 in myeloid cells resulted in significant elevation of serum ALT and liver fibrosis, but mildly affected hepatic inflammation after CCl4 treatment. We further observed significant elevation of elevation of stellate cell activation and SMAD2/3 activation in SIRT7MKO mice. By using primary HSCs and stellate cell line, we confirmed that SIRT7 interacted with SMAD2/3, induced its deacetylation and was critical in regulation of SMAD2/3 activation and stellate cell activation upon TGF-β stimulation. Pharmacological inhibition of SMAD2/3 reversed the hyperactivation of SIRT7MKO HSCs after TGF-β stimulation, and abolished stellate cell activation and liver fibrosis in SIRT7MKO mice.

CONCLUSION

Our findings revealed previously unidentified role of SIRT7 in regulating HSCs activation via modulating TGF-β/SMAD2/3 signaling pathway. Targeting SIRT7 might offer novel therapeutic option against liver fibrosis.

Elucidating the Role of Sirtuin 3 in Mammalian Oocyte Aging

The field of reproductive biology has made significant progress in recent years, identifying specific molecular players that influence oocyte development and function. Among them, sirtuin 3 (SIRT3) has attracted particular attention for its central role in mediating mitochondrial function and cellular stress responses in oocytes. So far, studies have demonstrated that the knockdown of SIRT3 leads to a decrease in blastocyst formation and an increase in oxidative stress within an embryo, underscoring the importance of SIRT3 in maintaining the cellular redox balance critical for embryonic survival and growth. Furthermore, the literature reveals specific signaling pathways, such as the SIRT3- Glycogen synthase kinase-3 beta (GSK3β) deacetylation pathway, crucial for mitigating oxidative stress-related anomalies in oocyte meiosis, particularly under conditions like maternal diabetes. Overall, the emerging role of SIRT3 in regulating oocyte mitochondrial function and development highlights the critical importance of understanding the intricate connections between cellular metabolism, stress response pathways, and overall reproductive health and function. This knowledge could lead to the development of novel strategies to support oocyte quality and fertility, with far-reaching implications for assisted reproductive technologies and women's healthcare. This commentary aims to provide an overview of the importance of SIRT3 in oocytes by synthesizing results from a multitude of studies. The aim is to elucidate the role of SIRT3 in oocyte development, maturation, and aging and to identify areas where further research is needed.

Metabolic mechanisms orchestrated by Sirtuin family to modulate inflammatory responses

Maintaining metabolic homeostasis is crucial for cellular and organismal health throughout their lifespans. The intricate link between metabolism and inflammation through immunometabolism is pivotal in maintaining overall health and disease progression. The multifactorial nature of metabolic and inflammatory processes makes study of the relationship between them challenging. Homologs of Saccharomyces cerevisiae silent information regulator 2 protein, known as Sirtuins (SIRTs), have been demonstrated to promote longevity in various organisms. As nicotinamide adenine dinucleotide-dependent deacetylases, members of the Sirtuin family (SIRT1-7) regulate energy metabolism and inflammation. In this review, we provide an extensive analysis of SIRTs involved in regulating key metabolic pathways, including glucose, lipid, and amino acid metabolism. Furthermore, we systematically describe how the SIRTs influence inflammatory responses by modulating metabolic pathways, as well as inflammatory cells, mediators, and pathways. Current research findings on the preferential roles of different SIRTs in metabolic disorders and inflammation underscore the potential of SIRTs as viable pharmacological and therapeutic targets. Future research should focus on the development of promising compounds that target SIRTs, with the aim of enhancing their anti-inflammatory activity by influencing metabolic pathways within inflammatory cells.

Crossing epigenetic frontiers: the intersection of novel histone modifications and diseases

Histone post-translational modifications (HPTMs), as one of the core mechanisms of epigenetic regulation, are garnering increasing attention due to their close association with the onset and progression of diseases and their potential as targeted therapeutic agents. Advances in high-throughput molecular tools and the abundance of bioinformatics data have led to the discovery of novel HPTMs which similarly affect gene expression, metabolism, and chromatin structure. Furthermore, a growing body of research has demonstrated that novel histone modifications also play crucial roles in the development and progression of various diseases, including various cancers, cardiovascular diseases, infectious diseases, psychiatric disorders, and reproductive system diseases. This review defines nine novel histone modifications: lactylation, citrullination, crotonylation, succinylation, SUMOylation, propionylation, butyrylation, 2-hydroxyisobutyrylation, and 2-hydroxybutyrylation. It comprehensively introduces the modification processes of these nine novel HPTMs, their roles in transcription, replication, DNA repair and recombination, metabolism, and chromatin structure, as well as their involvement in promoting the occurrence and development of various diseases and their clinical applications as therapeutic targets and potential biomarkers. Moreover, this review provides a detailed overview of novel HPTM inhibitors targeting various targets and their emerging strategies in the treatment of multiple diseases while offering insights into their future development prospects and challenges. Additionally, we briefly introduce novel epigenetic research techniques and their applications in the field of novel HPTM research.

Dietary-timing-induced gut microbiota diurnal oscillations modulate inflammatory rhythms in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune condition characterized by inflammatory activity with distinct rhythmic fluctuations. However, the precise mechanisms governing these inflammatory rhythms remain elusive. Here, we explore the interaction between dietary patterns, gut microbiota diurnal oscillations, and the rhythmicity of RA in both collagen-induced arthritis (CIA) mice and patients with RA and highlight the significance of dietary timing in modulating RA inflammatory rhythms linked to gut microbiota. Specifically, we discovered that Parabacteroides distasonis (P. distasonis) uses β-glucosidase (β-GC) to release glycitein (GLY) from the diet in response to daily nutritional cues, influencing RA inflammatory rhythms dependent on the sirtuin 5-nuclear factor-κB (SIRT5-NF-κB) axis. Notably, we validated the daily fluctuations of P. distasonis-β-GC-GLY in patients with RA through continuous sampling across day-night cycles. These findings underscore the crucial role of dietary timing in RA rhythmicity and propose potential clinical implications for novel therapeutic strategies to alleviate arthritis.

Chitosan/hesperidin nanoparticles formulation: a promising approach against ethanol-induced gastric ulcers via Sirt1/FOXO1/PGC-1α/HO-1 pathway

Hesperidin (Hes) protects different organs from damage by acting as a potent antioxidant and anti-inflammatory. This study aims to evaluate the gastroprotective effects of free hesperidin and its chitosan nanoparticles (HNPs) against ethanol-induced gastric ulcers in rats, hypothesizing that HNPs will enhance bioavailability and therapeutic efficacy due to improved solubility and targeted delivery. HNPs were synthesized via ion gelation and characterized using TEM, SEM, and zeta potential analyses. Key assessments included gastric acidity, histological analysis, and markers of inflammation, oxidative stress, and apoptosis. HNPs significantly decreased gastric acidity, reduced inflammatory and apoptotic markers, and enhanced antioxidant enzyme activities compared to free hesperidin and esomeprazole. Furthermore, Sirt-1, PGC-1α, HO-1, and FOXO1 gene expression were also evaluated. HNPs raised Sirt-1, PGC-1α, HO-1, and downregulated FOXO1, and they suppressed the activities of NF-κB p65, COX-2, IL-1β, CD86, FOXO1 P53, and caspase-3 and increased Sirt-1 activity. HNPs treatment notably restored antioxidant enzyme activity, reduced oxidative stress and inflammatory markers, and improved histological outcomes more effectively than free hesperidin and esomeprazole. These results indicate that chitosan nanoparticles significantly enhance the gastroprotective effects of hesperidin against ethanol-induced gastric ulcers, potentially offering a more effective therapeutic strategy. Further research should explore the clinical applications of HNPs in human subjects.

Pleiotropic Effects of Peroxisome Proliferator-Activated Receptor Alpha and Gamma Agonists on Myocardial Damage: Molecular Mechanisms and Clinical Evidence-A Narrative Review

Cardiovascular diseases remain the leading cause of death in the world, and that is why finding an effective and multi-functional treatment alternative to combat these diseases has become more important. Fibrates and thiazolidinediones, peroxisome proliferator-activated receptors alpha and gamma are the pharmacological therapies used to treat dyslipidemia and type 2 diabetes, respectively. New mechanisms of action of these drugs have been found, demonstrating their pleiotropic effects, which contribute to preserving the heart by reducing or even preventing myocardial damage. Here, we review the mechanisms underlying the cardioprotective effects of PPAR agonists and regulating morphological and physiological heart alterations (metabolic flexibility, mitochondrial damage, apoptosis, structural remodeling, and inflammation). Moreover, clinical evidence regarding the cardioprotective effect of PPAR agonists is also addressed.

Biological Functions and Therapeutic Potential of NAD+ Metabolism in Gynecological Cancers

Nicotinamide adenine dinucleotide (NAD+) is an important cofactor for both metabolic and signaling pathways, with the dysregulation of NAD+ levels acting as a driver for diseases such as neurodegeneration, cancers, and metabolic diseases. NAD+ plays an essential role in regulating the growth and progression of cancers by controlling important cellular processes including metabolism, transcription, and translation. NAD+ regulates several metabolic pathways such as glycolysis, the citric acid (TCA) cycle, oxidative phosphorylation, and fatty acid oxidation by acting as a cofactor for redox reactions. Additionally, NAD+ acts as a cofactor for ADP-ribosyl transferases and sirtuins, as well as regulating cellular ADP-ribosylation and deacetylation levels, respectively. The cleavage of NAD+ by CD38-an NAD+ hydrolase expressed on immune cells-produces the immunosuppressive metabolite adenosine. As a result, metabolizing and maintaining NAD+ levels remain crucial for the function of various cells found in the tumor microenvironment, hence its critical role in tissue homeostasis. The NAD+ levels in cells are maintained by a balance between NAD+ biosynthesis and consumption, with synthesis being controlled by the Preiss-Handler, de novo, and NAD+ salvage pathways. The primary source of NAD+ synthesis in a variety of cell types is directed by the expression of the enzymes central to the three biosynthesis pathways. In this review, we describe the role of NAD+ metabolism and its synthesizing and consuming enzymes' control of cancer cell growth and immune responses in gynecologic cancers. Additionally, we review the ongoing efforts to therapeutically target the enzymes critical for NAD+ homeostasis in gynecologic cancers.

A proteasome-dependent inhibition of SIRT-1 by the resveratrol analogue 4,4'-dihydroxy-trans-stilbene

Background and aim

Resveratrol (RSV), is a stilbene-based compound exerting wide biological properties. Its analogue 4,4'-dihydroxy-trans-stilbene (DHS) has shown improved bioavailability and antiproliferative activity in vitro and in vivo. One of the hypotheses on how resveratrol works is based on SIRT1 activation. Since their strict structural similarities, we have explored a potential interaction between DHS and SIRT1, in comparison with the parental molecule.

Experimental procedure

Timing of incubation and concentrations of DHS have been determined using MTT assay in normal human lung fibroblasts. Untreated, DHS- or RSV-treated cells were harvested and analysed by Western Blotting or RT-PCR, in order to evaluate SIRT1 levels/activity and expression, and by Cellular Thermal shift assay (CETSA) to check potential DHS or RSV-SIRT1 interaction. Transfection experiments have been performed with two SIRT1 mutants, based on the potential binding pockets identified by Molecular Docking analysis.

Results and conclusion

We unexpectedly found that DHS, but not RSV, exerted a time-dependent inhibitory effect on both SIRT1 protein levels and activity, the latter measured as p53 acetylation. At the mRNA level no significant changes were observed, whereas a proteasome-dependent mechanism was highlighted for the reduction of SIRT1 levels by DHS in experiments performed with the proteasome inhibitor MG132. Bioinformatics analysis suggested a higher affinity of RSV in binding all SIRT1 complexes compared to DHS, except comparable results for complex SIRT1-p53. Nevertheless, both CETSA and SIRT1 mutants transfected in cells did not confirm this interaction. In conclusion, DHS reduces SIRT1 protein level, thereby inhibiting its activity through a proteasome-mediated mechanism.

SIRT1: a novel regulator in colorectal cancer

The class-III histone deacetylase SIRT1 is the most extensively investigated sirtuin deacetylase. It is resistant to the broad deacetylase inhibitor trichostatin A and depends on oxidized nicotinamide adenine nucleotide (NAD+). SIRT1 plays a crucial role in the tumorigenesis of numerous types of cancers, including colorectal cancer (CRC). Accumulating evidence indicates that SIRT1 is a therapeutic target for CRC; however, the function and underlying mechanism of SIRT1 in CRC still need to be elucidated. Herein, we provide a detailed and updated review to illustrate that SIRT1 regulates many processes that go awry in CRC cells, such as apoptosis, autophagy, proliferation, migration, invasion, metastasis, oxidative stress, resistance to chemo-radio therapy, immune evasion, and metabolic reprogramming. Moreover, we closely link our review to the clinical practice of CRC treatment, summarizing the mechanisms and prospects of SIRT1 inhibitors in CRC therapy. SIRT1 inhibitors as monotherapy in CRC or in combination with chemotherapy, radiotherapy, and immune therapies are comprehensively discussed. From epigenetic regulation to its potential therapeutic effect, we hope to offer novel insights and a comprehensive understanding of SIRT1's role in CRC.

Nicotine induces senescence in spermatogonia stem cells by disrupting homeostasis between circadian oscillation and rhythmic mitochondrial dynamics via the SIRT6/Bmal1 pathway

Infertility is intricately linked with alterations in circadian rhythms along with physiological decline and stem cell senescence. Yet, the direct involvement of circadian mechanisms in nicotine-induced injury to the testes, especially the senescence of spermatogonia stem cells (SSCs), is not well comprehended. This study revealed that nicotine exposure induced testis injury by triggering SSCs senescence along with the upregulation of senescence marker genes and senescence-associated secretory phenotype components. Moreover, nicotine treatment caused mitochondrial hyper-fusion, increased oxidative stress, and DNA damage. Exposure to nicotine was found to suppress the expression of sirtuin 6 (SIRT6), which accelerated the senescence of spermatogonia stem cells (SSCs). This acceleration led to increased acetylation of brain and muscle ARNT-like protein (Bmal1), consequently reducing the expression of Bmal1 protein. Conversely, the overexpression of Bmal1 alleviated mitochondrial hyper-fusion and senescence phenotypes induced by nicotine. Overall, this study unveiled a novel molecular mechanism behind nicotine-induced disorders in spermatogenesis and highlighted the SIRT6/Bmal1 regulatory pathway as a potential therapeutic target for combating nicotine-associated infertility.

The role of sirtuins in intervertebral disc degeneration: Mechanisms and therapeutic potential

Intervertebral disc degeneration (IDD) is one of the main causes of low back pain, which affects the patients' quality of life and health and imposes a significant socioeconomic burden. Despite great efforts made by researchers to understand the pathogenesis of IDD, effective strategies for preventing and treating this disease remain very limited. Sirtuins are a highly conserved family of (NAD+)-dependent deacetylases in mammals that are involved in a variety of metabolic processes in vivo. In recent years, sirtuins have attracted much attention owing to their regulatory roles in IDD on physiological activities such as inflammation, apoptosis, autophagy, aging, oxidative stress, and mitochondrial function. At the same time, many studies have explored the therapeutic effects of sirtuins-targeting activators or micro-RNA in IDD. This review summarizes the molecular pathways of sirtuins involved in IDD, and summarizes the therapeutic role of activators or micro-RNA targeting Sirtuins in IDD, as well as the current limitations and challenges, with a view to provide possible solutions for the treatment of IDD.

SIRT7 promotes mitochondrial biogenesis to render the adaptive resistance to MAPK inhibition in melanoma

Melanoma, arising from the malignant transformation of melanocytes, stands as the most lethal type of skin cancer. While significant strides have been made in targeted therapy and immunotherapy, substantially enhancing therapeutic efficacy, the prognosis for melanoma patients remains unoptimistic. SIRT7, a nuclear-localized deacetylase, plays a pivotal role in maintaining cellular homeostasis and adapting to external stressors in melanoma, with its activity closely tied to intracellular nicotinamide adenine dinucleotide (NAD+). However, its involvement in adaptive resistance to targeted therapy remains unclear. Herein, we unveil that up-regulated SIRT7 promotes mitochondrial biogenesis to render the adaptive resistance to MAPK inhibition in melanoma. Initially, we observed a significant increase of SIRT7 expression in publicly available datasets following targeted therapy within a short duration. In consistent, we found elevated SIRT7 expression in melanoma cells subjected to BRAF or MEK inhibitors in vitro. The up-regulation of SIRT7 expression was also confirmed in xenograft tumors in mice after targeted therapy in vivo. Furthermore, we proved that SIRT7 deficiency led to decreased cell viability upon prolonged exposure to BRAF or MEK inhibitors, accompanied by an increase in cell apoptosis. Mechanistically, SIRT7 deficiency restrained the upregulation of genes associated with mitochondrial biogenesis and intracellular ATP levels in response to targeted therapy treatment in melanoma cells. Ultimately, we proved that SIRT7 deficieny could sensitize BRAF-mutant melanoma cells to MAPK inhibition targeted therapy in vivo. In conclusion, our findings underscore the role of SIRT7 in fostering adaptive resistance to targeted therapy through the facilitation of mitochondrial biogenesis. Targeting SIRT7 emerges as a promising strategy to overcome MAPK inhibitor adaptive resistance in melanoma.

Oxidative stress and senescence in aging kidneys: the protective role of SIRT1

Aging leads to a gradual decline in kidney function, making the kidneys increasingly vulnerable to various diseases. Oxidative stress, together with cellular senescence, has been established as paramount in promoting the aging process of the kidney. Oxidative stress, defined as an imbalance between ROS formation and antioxidant defense mechanisms, has been implicated in the kidney's cellular injury, inflammation, and premature senescence. Concurrently, the accumulation of SCs in the kidney also exacerbates oxidative stress via the secretion of pro-inflammatory and tissue-damaging factors as the senescence-associated secretory phenotype (SASP). Recently, SIRT1, a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, has been pivotal in combating oxidative stress and cellular senescence in the aging kidney. SIRT1 acts as a potential antioxidant molecule through myriad pathways that influence diverse transcription factors and enzymes essential in maintaining redox homeostasis. SIRT1 promotes longevity and renal health by modulating the acetylation of cell cycle and senescence pathways. This review covers the complex relationship between oxidative stress and cellular senescence in the aging kidney, emphasizing the protective role of SIRT1. See also the graphical abstract(Fig. 1).

Monitoring nucleolar-nucleoplasmic protein shuttling in living cells by high-content microscopy and automated image analysis

The nucleolus has core functions in ribosome biosynthesis, but also acts as a regulatory hub in a plethora of non-canonical processes, including cellular stress. Upon DNA damage, several DNA repair factors shuttle between the nucleolus and the nucleoplasm. Yet, the molecular mechanisms underlying such spatio-temporal protein dynamics remain to be deciphered. Here, we present a novel imaging platform to investigate nucleolar-nucleoplasmic protein shuttling in living cells. For image acquisition, we used a commercially available automated fluorescence microscope and for image analysis, we developed a KNIME workflow with implementation of machine learning-based tools. We validated the method with different nucleolar proteins, i.e., PARP1, TARG1 and APE1, by monitoring their shuttling dynamics upon oxidative stress. As a paradigm, we analyzed PARP1 shuttling upon H2O2 treatment in combination with a range of pharmacological inhibitors in a novel reporter cell line. These experiments revealed that inhibition of SIRT7 results in a loss of nucleolar PARP1 localization. Finally, we unraveled specific differences in PARP1 shuttling dynamics after co-treatment with H2O2 and different clinical PARP inhibitors. Collectively, this work delineates a highly sensitive and versatile bioimaging platform to investigate swift nucleolar-nucleoplasmic protein shuttling in living cells, which can be employed for pharmacological screening and in-depth mechanistic analyses.

Editorial Commentary on the Special Issue "Antioxidant Therapy for Cardiovascular Diseases"-Cutting-Edge Insights into Oxidative Stress and Antioxidant Therapy in Cardiovascular Health

Recent advances in cardiovascular research have increasingly emphasized oxidative stress as a central mechanism in the pathogenesis and progression of cardiovascular diseases [...].

Hypoxic-preconditioned mesenchymal stem cell-derived small extracellular vesicles inhibit neuronal death after spinal cord injury by regulating the SIRT1/Nrf2/HO-1 pathway

Background

Oxidative stress and apoptosis of neurons significantly contribute to the pathophysiological cascade of spinal cord injury (SCI). However, the role of hypoxic-preconditioned mesenchymal stem cell-derived small extracellular vesicles (H-sEVs) in promoting SCI repair remains unclear. Hence, the present study aims to investigate the regulatory effects of H-sEVs on neuronal oxidative stress and apoptotic responses following SCI.

Methods

The administration of H-sEVs of SCI rats was assessed using behavioral evaluations such as Basso-Beattie-Bresnahan (BBB) scores, neuroelectrophysiological monitoring, and Catwalk gait analysis. Indices of oxidative stress (including superoxide dismutase [SOD], total antioxidant capacity [T-AOC], and malondialdehyde [MDA]) were measured. Neuronal survival was evaluated through Nissl staining, while the expression level of sirtuin 1 (SIRT1) was examined using immunohistochemical staining. Additionally, histological evaluation of lesion size was performed using hematoxylin-eosin (HE) staining. Tunel cell apoptosis staining and analysis of apoptosis-associated proteins (B-cell lymphoma-2 [Bcl2] and BCL2-Associated X [Bax]) were conducted through immunofluorescence staining and western blot, respectively. Furthermore, the model of oxidative stress was established using PC12 cells, and apoptosis levels were assessed via flow cytometry and western blot analysis. Importantly, to ascertain the critical role of SIRT1, we performed SIRT1 knockout experiments in PC12 cells using lentivirus transfection, followed by western blot.

Results

Using those behavioral evaluations, we observed significant functional improvement after H-sEVs treatment. Nissl staining revealed that H-sEVs treatment promoted neuronal survival. Moreover, we found that H-sEVs effectively reduced oxidative stress levels after SCI. HE staining demonstrated that H-sEVs could reduce lesion area. Immunohistochemical analysis revealed that H-sEVs enhanced SIRT1 expression. Furthermore, Tunel cell apoptosis staining and western blot analysis of apoptosis-related proteins confirmed the anti-apoptotic effects of H-sEVs. The PC12 cells were used to further substantiate the neuroprotective properties of H-sEVs by significantly inhibiting neuronal death and attenuating oxidative stress. Remarkably, SIRT1 knockout in PC12 cells reversed the antioxidant stress effects induced by H-sEVs treatment. Additionally, we elucidated the involvement of the downstream Nrf2/HO-1 signaling pathway.

Conclusion

Our study provides valuable insights into the effects of H-sEVs on neuronal oxidative stress and apoptosis after SCI. These findings underscore the potential clinical significance of H-sEVs-based therapies for SCI.

Renal Fibrosis: SIRT1 Still of Value

Chronic kidney disease (CKD) is a major global health concern. Renal fibrosis, a prevalent outcome regardless of the initial cause, ultimately leads to end-stage renal disease. Glomerulosclerosis and renal interstitial fibrosis are the primary pathological features. Preventing and slowing renal fibrosis are considered effective strategies for delaying CKD progression. However, effective treatments are lacking. Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase belonging to class III histone deacetylases, is implicated in the physiological regulation and protection of the kidney and is susceptible to a diverse array of pathological influences, as demonstrated in previous studies. Interestingly, controversial conclusions have emerged as research has progressed. This review provides a comprehensive summary of the current understanding and advancements in the field; specifically, the biological roles and mechanisms of SIRT1 in regulating renal fibrosis progression. These include aspects such as lipid metabolism, epithelial-mesenchymal transition, oxidative stress, aging, inflammation, and autophagy. This manuscript explores the potential of SIRT1 as a therapeutic target for renal fibrosis and offers new perspectives on treatment approaches and prognostic assessments.

A Multi-Target Pharmacological Correction of a Lipoyltransferase LIPT1 Gene Mutation in Patient-Derived Cellular Models

Mutations in the lipoyltransferase 1 (LIPT1) gene are rare inborn errors of metabolism leading to a fatal condition characterized by lipoylation defects of the 2-ketoacid dehydrogenase complexes causing early-onset seizures, psychomotor retardation, abnormal muscle tone, severe lactic acidosis, and increased urine lactate, ketoglutarate, and 2-oxoacid levels. In this article, we characterized the disease pathophysiology using fibroblasts and induced neurons derived from a patient bearing a compound heterozygous mutation in LIPT1. A Western blot analysis revealed a reduced expression of LIPT1 and absent expression of lipoylated pyruvate dehydrogenase E2 (PDH E2) and alpha-ketoglutarate dehydrogenase E2 (α-KGDH E2) subunits. Accordingly, activities of PDH and α-KGDH were markedly reduced, associated with cell bioenergetics failure, iron accumulation, and lipid peroxidation. In addition, using a pharmacological screening, we identified a cocktail of antioxidants and mitochondrial boosting agents consisting of pantothenate, nicotinamide, vitamin E, thiamine, biotin, and α-lipoic acid, which is capable of rescuing LIPT1 pathophysiology, increasing the LIPT1 expression and lipoylation of mitochondrial proteins, improving cell bioenergetics, and eliminating iron overload and lipid peroxidation. Furthermore, our data suggest that the beneficial effect of the treatment is mainly mediated by SIRT3 activation. In conclusion, we have identified a promising therapeutic approach for correcting LIPT1 mutations.

Targeting SIRT2 in Aging-Associated Fibrosis Pathophysiology

Aging is a complex biological process that involves multi-level structural and physiological changes. Aging is a major risk factor for many chronic diseases. The accumulation of senescent cells changes the tissue microenvironment and is closely associated with the occurrence and development of tissue and organ fibrosis. Fibrosis is the result of dysregulated tissue repair response in the development of chronic inflammatory diseases. Recent studies have clearly indicated that SIRT2 is involved in regulating the progression of fibrosis, making it a potential target for anti-fibrotic drugs. SIRT2 is a NAD+ dependent histone deacetylase, shuttling between nucleus and cytoplasm, and is highly expressed in liver, kidney and heart, playing an important role in the occurrence and development of aging and fibrosis. Therefore, we summarized the role of SIRT2 in liver, kidney and cardiac fibrosis during aging.