Sirtuins as regulators of metabolism and healthspan. Nat Rev Mol Cell Biol. 2012;13:225-238. [PMID: 22395773 DOI: 10.1038/nrm3293]

Design and synthetic approaches to thalidomide based small molecule degraders

Thalidomide has been used as a repurposed drug for treating multiple myeloma since 1997. Several novel anticancer drugs containing thalidomide active moiety has been discovered since then. Many thalidomide drug candidates with tuned linker size have been instrumental in inhibiting histone deacetylase, kinase, transcription factors etc. and facilitate selective degradation of E3 ligase and other enzymes. Here we are focused on small molecule degraders that are being tailored with tweaking synthetic architectures around thalidomide chemical motif towards the development of promising drug candidates. Interesting biomedical applications of thalidomide-based degraders with recent developments including pharmacokinetic profiles, protein stability, activity studies, degradation assays, and antitumor response are elucidated.

DBC1 promotes intervertebral disc degeneration by activating NF-κB pathway and inhibiting SIRT1 activity

AIMS

Intervertebral disc degeneration (IVDD) is a leading contributor to spinal degenerative diseases; however, its pathogenesis remains only partially elucidated. Recent studies have highlighted that the diminished activity of SIRT1 and the aberrant activation of the NF-κB signaling pathway are critical pathogenic factors in IVDD. DBC1 has been identified as a regulator of SIRT1 activity and the NF-κB signaling pathway. This study aimed to investigate the role of DBC1 in IVDD.

MATERIALS AND METHODS

The expression levels of DBC1 in the nucleus pulposus of aging rats were quantified. Both overexpression and knockdown of DBC1 were utilized to explore their effects on the extracellular matrix (ECM) of the nucleus pulposus. Furthermore, the influence of DBC1 on cellular senescence, apoptosis, and ECM regulation in nucleus pulposus cells was assessed using Western blot (WB), cellular fluorescence assays, and histological staining techniques.

KEY FINDINGS

Our results demonstrate that DBC1 expression is significantly upregulated in IVDD. Moreover, DBC1 appears to contribute to IVDD by promoting apoptosis, senescence, and ECM degradation in nucleus pulposus cells. Mechanistic investigations revealed that DBC1 activates the NF-κB signaling pathway while suppressing SIRT1 expression in nucleus pulposus cells, suggesting that these two mechanisms underlie its effects on IVDD.

SIGNIFICANCE

In summary, this study provides evidence that DBC1 may play a pivotal role in the pathogenesis of IVDD by inhibiting SIRT1 activity and activating the NF-κB signaling pathway. Consequently, targeting DBC1 suppression could represent a promising therapeutic strategy for managing IVDD.

Metabolic Alterations in HSCs during Aging and Leukemogenesis

Aging is a multifaceted process associated with a functional decline in cellular function over time, affecting all lifeforms. During the aging process, metabolism, a fundamental hallmark of life (1), is profoundly altered. In the context of hematopoiesis, the proper function of hematopoietic stem cells, at the apex of the blood system, is tightly linked to their energy metabolism, which in turn shapes hematopoietic output. Here, we review the latest developments in our understanding of the metabolic states and changes in aged hematopoietic stem cells, molecular players and pathways involved in aged hematopoietic stem cell metabolism, the consequences of perturbed metabolism on clonal hematopoiesis and leukemogenesis, and pharmacologic/genetic strategies to reverse or rejuvenate altered metabolic phenotypes.

The role of sirtuins in the regulation of reactive oxygen species in myocardial ischemia/reperfusion injury

Myocardial ischemia/reperfusion (I/R) injury has high morbidity and mortality rates, posing a significant burden on society. There is an urgent need to understand its pathogenesis and develop effective treatments. Reactive oxygen species (ROS) are crucial for the development of myocardial I/R injury, and inhibiting ROS overproduction is one of the most critical ways to delay myocardial I/R injury. Sirtuins are a group of nicotinic adenine dinucleotide ( +)-dependent histone deacetylases whose members can regulate ROS by modulating various biological processes. Numerous studies have shown that Sirtuins play an essential role in the progression of myocardial I/R injury by regulating ROS. This study focuses on the relationship between myocardial I/R injury and ROS, Sirtuins and ROS, discusses the role of Sirtuins in regulating ROS in myocardial I/R, and summarizes the therapeutic modalities aimed at targeting Sirtuins to modulate ROS in myocardial I/R injury, thereby guiding future research endeavors.

Transporters in vitamin uptake and cellular metabolism: impacts on health and disease

Vitamins are vital nutrients essential for metabolism, functioning as coenzymes, antioxidants, and regulators of gene expression. Their absorption and metabolism rely on specialized transport proteins that ensure bioavailability and cellular utilization. Water-soluble vitamins, including B-complex and vitamin C, are transported by solute carrier (SLC) family proteins and ATP-binding cassette (ABC) transporters for efficient uptake and cellular distribution. Fat-soluble vitamins (A, D, E, and K) rely on lipid-mediated pathways through proteins like scavenger receptor class B type I (SR-BI), CD36, and Niemann-Pick C1-like 1 (NPC1L1), integrating their absorption with lipid metabolism. Defective vitamin transporters are associated with diverse metabolic disorders, including neurological, hematological, and mitochondrial diseases. Advances in structural and functional studies of vitamin transporters highlight their tissue-specific roles and regulatory mechanisms, shedding light on their impact on health and disease. This review emphasizes the significance of vitamin transporters and their potential as therapeutic targets for deficiencies and related chronic conditions.

Protein Ubiquitination Modification in Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a chronic, progressive fibrotic interstitial lung disease characterized by a high incidence and mortality rate, which encompasses features, such as diffuse alveolar inflammation, invasive fibroblast activation, and uncontrolled extracellular matrix (ECM) deposition. Beyond the local pathological processes, PF can be better understood in light of interorgan communication networks that are involved in its progression. Notably, pulmonary inflammation can affect cardiovascular, renal, hepatic, and neural functions, highlighting the importance of understanding these systemic interactions. Posttranslational modifications play a crucial role in regulating protein function, localization, stability, and activity. Specifically, protein ubiquitination modifications are involved in PF induced by various stimuli, involving a range of ubiquitin-modifying enzymes and substrates. In this review, we provide an overview of how E3 ubiquitin ligases and deubiquitinating enzymes (DUBs) modulate PF through several signaling pathways, such as TGF-β, Wnt, metabolic activity, aging, ferroptosis, endoplasmic reticulum stress, and inflammatory responses. This perspective includes the role of ubiquitin-proteasome systems in interorgan communication, affecting the progression of PF and related systemic conditions. Additionally, we also summarize the currently available therapeutic compounds targeting protein ubiquitination-related enzymes or ubiquitination substrates for the treatment of PF. Understanding the interplay between ubiquitination and interorgan communication may pave the way for novel therapeutic strategies.

Genome-wide identification and expression analysis of the SIRT gene family in Nile tilapia (Oreochromis niloticus)

The sirtuin (SIRT) family is a nicotine adenine dinucleotide (NAD+)-dependent class III histone deacetylase, which is widely involved in numerous physiological processes of organisms, such as metabolism, reproduction, and immunity. Here, based on the genomics database, comprehensive analysis of the SIRT gene in Nile tilapia (Oreochromis niloticus) was analyzed using bioinformatics methods and quantitative real-time PCR. The nine SIRT genes of O. niloticus (OnSIRT) were distributed on eight chromosomes. The OnSIRTs contain distinct sequences from 3 exons in OnSIRT4 to 16 exons in OnSIRT2, however, they share conserved domains and protein motifs. Phylogenetic analysis shows that the OnSIRTs belong to four subfamilies and are highly conserved in teleosts, and evolution is characterized primarily by purification selection. The OnSIRT genes showed diversified expression patterns in fourteen tissues of O. niloticus. OnSIRT2, OnSIRT3, OnSIRT3.2, OnSIRT6, and OnSIRT7 are mainly expressed in the gonads, especially in the ovary. OnSIRT1 and OnSIRT4 are mainly expressed in the kidney. OnSIRT5a is mainly expressed in the stomach, however, OnSIRT5b is mainly expressed in the liver and spleen. The results of this study provide a basis information for further exploration of the function and molecular mechanism of the SIRT gene family in teleosts.

Structural basis for sirtuin 2 activity and modulation: current state and opportunities

Sirtuin 2 (SIRT2) is a ubiquitously expressed cellular enzyme that deacylates protein lysine residues using NAD+ as a cofactor. SIRT2-mediated post-translational modifications on a plethora of protein targets position the enzyme to exert a wide-ranging regulatory role in many physiological and pathological processes. More than 39 SIRT2 crystal structures in complex with substrates, products, mimetics of substrates and products, and modulators, have been reported. The Rossmann fold of the catalytic core presents inducible acyl and cofactor binding cavities that accommodate acyl chains of diverse lengths. These structures have provided information for the design of mechanism- and substrate-based inhibitors. Indeed, a specific SIRT2 selectivity pocket has been described and can be targeted by different chemotypes. Despite the determination of many crystal structures, numerous open questions remain, especially relating to the development of small molecule modulators, full or partial activation or inhibition, and relating these effects to different therapeutic applications. Additional questions include understanding the role of the disordered termini, and the role of potential quaternary states (monomer, dimer, and trimer). Deeper insight into these issues may facilitate the development of SIRT2 selective modulators that can be tailored to different pathological scenarios, such as viral infections and cancers, in which either activation or inhibition of SIRT2 may be of therapeutic benefit. This review covers the following topics: (1) primary to quaternary and catalytic structural biology; (2) structural insights into molecular modulation of SIRT2 (inhibition and selectivity by mechanism-based inhibitors, substrate-mimicking inhibitors, C pocket-binding inhibitors, and selectivity pocket binding inhibitors, including insights to activation; and (3) the impact of structural variations (mutations, post-translational modifications, polymorphs, protein interactions). Despite considerable progress, key knowledge gaps remain regarding the design of optimized SIRT2 modulators. Addressing these uncertainties, particularly within the realms of full/partial activation/inhibition, off-target effects, and tailoring modulators to specific pathologies, will require further investigation into the roles of the SIRT2 disordered termini, quaternary states, and post-translational modifications. Ultimately, unraveling these intricacies holds the key to unlocking the therapeutic potential of SIRT2 modulation.

Synergistic Impact of Aerobic Exercise and Resveratrol on White Adipose Tissue Browning in Obese Rats: Mechanistic Exploration and Biological Insights

Obesity, marked by excessive white adipose tissue (WAT) accumulation, worsens metabolic disorders, and inducing WAT browning is a promising therapy. This study examined the synergistic effects of moderate-intensity aerobic training and resveratrol (RES) on WAT browning and its underlying mechanisms in obese male rats. Methods: Male Sprague Dawley rats were divided into a normal diet control group (n = 8) and a high-fat-diet modeling group (n = 32), with the rats in the latter group being further divided randomly in groups of eight into a high-fat group; a high-fat, exercise group; a high-fat, RES group; and a high-fat, exercise-combined-with-RES group. The rats in the exercise intervention groups underwent moderate-intensity aerobic treadmill exercise for one hour daily, six days a week, while those in the RES groups received a 50 mg/kg/d RES solution via gavage before exercise, once daily, six days a week. Both interventions lasted eight weeks. Results: The combined intervention synergistically suppressed weight gain and visceral fat accumulation. WAT browning was enhanced, evidenced by upregulated UCP1 and CIDEA expression. Mitochondrial biogenesis was activated via the SIRT1-PGC-1α-NRF-1-TFAM pathway, accompanied by elevated mitochondrial enzyme activity and improved lipid mobilization (reduced serum free fatty acids and triglycerides). Conclusions: The combination of aerobic exercise and RES promotes WAT browning and lipolysis by enhancing mitochondrial biogenesis and stimulating mitochondrial thermogenesis through the modulation of the SIRT1-PGC-1α-NRF-1-TFAM pathway.

SIRT5-mediated desuccinylation of the porcine deltacoronavirus M protein drives pexophagy to enhance viral proliferation

Porcine deltacoronavirus (PDCoV) is an emerging enteropathogenic coronavirus capable of infecting various animal species, including humans. In this study, we explored the roles of sirtuins (SIRTs), a conserved family of protein deacylases and mono-adenosine diphosphate-ribosyltransferases, in PDCoV replication. Surprisingly, we found that SIRT5-a unique member of SIRTs with distinct desuccinylation, demalonylation, and deglutarylation activities-is a proviral factor essential for PDCoV replication; its catalytic activities are crucial in this process. Mechanistically, SIRT5 interacts with and desuccinylates the PDCoV membrane (M) protein. This modification activates the ataxia-telangiectasia mutated (ATM) pathway, facilitates ubiquitination of peroxisomal biogenesis protein 5 (PEX5), and recruits sequestosome 1 (SQSTM1/p62) to initiate selective peroxisomal autophagy (pexophagy). The pexophagy process disrupts peroxisomal function, elevates reactive oxygen species (ROS) levels, and suppresses type I and III interferon production, thereby enhancing viral replication. We also identified lysine 207 (K207) as the primary succinylation site of the M protein. Mutations mimicking the desuccinylated or succinylated states of K207 substantially influence viral replication and the ability to induce pexophagy. These findings reveal a novel role for SIRT5 in regulating pexophagy during viral infection and suggest a therapeutic target for efforts to combat coronavirus infections.

Down-regulating HDAC2-LTA4H pathway ameliorates renal ischemia-reperfusion injury

BACKGROUND

The activation of histone deacetylase 2 (HDAC2) is the main pathogenesis of acute kidney injury (AKI), one of the leading causes of end-stage kidney disease. However, the regulatory role of HDAC2 upregulation on inflammation in AKI is still unclear.

RESULTS

In this study, we found that treatment with HDAC2 inhibitor BRD6688 could mitigate the degree of mesangial sclerosis, interstitial infiltration and tubular atrophy, reduce the concentration of blood urea nitrogen (BUN) and serum creatinine (Scr), improve the proliferation, anti-apoptotic, anti-oxidative stress and angiogenesis effects of renal cells. Our results mainly indicated that renal HDAC2 activity was increased by casein kinase 2 (CK2) in renal ischemia reperfusion (I/R) models, and HDAC2 genetic ablation in HREpiC cells suppressed the leukotriene B4 (LTB4) production. Renal leukotriene A4 hydrolase (LTA4H) activity was increased in AKI mice in a HDAC2-dependent manner. LTB4 could induce monocytes to differentiate into M1 macrophages, while BRD6688 could suppress this effect and force the M1 macrophages polarize to M2 macrophages.

CONCLUSION

Inhibition of HDAC2 activities by BRD6688 could suppress the progression of renal I/R injury through the regulation of LTA4H and macrophage polarization.

Role of SIRT3 in the regulation of Gadd45α expression and DNA repair in β-cells

In previous studies, we have shown that growth arrest and DNA damage (Gadd) 45α is required for the repair of nitric oxide-mediated DNA damage in β-cells. Gadd45α expression is stimulated by nitric oxide and requires forkhead box protein (Fox) O1 and NAD+-dependent deacetylase activity. Based on inhibitor studies, we attributed this activity to Sirtuin (SIRT)1; however, the inhibitors used in this previous study also attenuate the deacetylase activity of SIRT2, 3, and 6. We now provide experimental evidence that SIRT1 is dispensable for β-cell expression of Gadd45α and that the mitochondrial localized isoform SIRT3, is required for DNA repair in β-cells. We show that siRNA knockdown of Sirt3 attenuates nitric oxide-stimulated Gadd45α mRNA accumulation in both wildtype and Sirt1-/- INS 832/13 cells as well as isolated rat islets and that SIRT3 inhibition increases FoxO1 acetylation and attenuates DNA repair in response to nitric oxide. While SIRT3 is predominantly localized to mitochondria, a small fraction is localized in the nucleus of insulin-containing cells and functions to participate in the regulation of FoxO1-dependent, nitric oxide-stimulated DNA repair.

Mitochondrial quality control: A promising target of traditional Chinese medicine in the treatment of cardiovascular disease

Cardiovascular disease remains the leading cause of death globally, and drugs for new targets are urgently needed. Mitochondria are the primary sources of cellular energy, play crucial roles in regulating cellular homeostasis, and are tightly associated with pathological processes in cardiovascular disease. In response to physiological signals and external stimuli in cardiovascular disease, mitochondrial quality control, which mainly includes mitophagy, mitochondrial dynamics, and mitochondrial biogenesis, is initiated to meet cellular requirements and maintain cellular homeostasis. Traditional Chinese Medicine (TCM) has been shown to have pharmacological effects on alleviating cardiac injury in various cardiovascular diseases, including myocardial ischemia/reperfusion, myocardial infarction, and heart failure, by regulating mitochondrial quality control. Recently, several molecular mechanisms of TCM in the treatment of cardiovascular disease have been elucidated. However, mitochondrial quality control by TCM for treating cardiovascular disease has not been investigated. In this review, we aim to decipher the pharmacological effects and molecular mechanisms of TCM in regulating mitochondrial quality in various cardiovascular diseases. We also present our perspectives regarding future research in this field.

Nicotinic acid riboside maintains NAD+ homeostasis and ameliorates aging-associated NAD+ decline

Liver-derived circulating nicotinamide from nicotinamide adenine dinucleotide (NAD+) catabolism primarily feeds systemic organs for NAD+ synthesis. We surprisingly found that, despite blunted hepatic NAD+ and nicotinamide production in liver-specific nicotinamide nucleotide adenylyltransferase 1 (NMNAT1) deletion mice (liver-specific knockout [LKO]), circulating nicotinamide and extra-hepatic organs' NAD+ are unaffected. Metabolomics reveals a massive accumulation of a novel molecule in the LKO liver, which we identify as nicotinic acid riboside (NaR). We further demonstrate cytosolic 5'-nucleotidase II (NT5C2) as the NaR-producing enzyme. The liver releases NaR to the bloodstream, and kidneys take up NaR to synthesize NAD+ through nicotinamide riboside kinase 1 (NRK1) and replenish circulating nicotinamide. Serum NaR levels decline with aging, whereas oral NaR supplementation in aged mice boosts serum nicotinamide and multi-organ NAD+, including kidneys, and reduces kidney inflammation and albuminuria. Thus, the liver-kidney axis maintains systemic NAD+ homeostasis via circulating NaR, and NaR supplement ameliorates aging-associated NAD+ decline and kidney dysfunction.

Mitonuclear Communication in Stem Cell Function

Mitochondria perform multiple functions within the cell, including the production of ATP and a great deal of metabolic intermediates, while also contributing to the cellular stress response. The majority of mitochondrial proteins are encoded by nuclear genomes, highlighting the importance of mitonuclear communication for sustaining mitochondrial homeostasis and functional. As a crucial part of the intracellular signalling network, mitochondria can impact stem cell fate determinations. Considering the essential function of stem cells in tissue maintenance, regeneration and aging, it is important to understand how mitochondria influence stem cell fate. This review explores the significant roles of mitonuclear communication and mitochondrial proteostasis, highlighting their influence on stem cells. We also examine how mitonuclear interactions contribute to cellular homeostasis, stem cell therapies, and the potential for extending lifespan.

NAD+ boosting increases atherosclerotic plaques and inflammation in Apoe knockout mice

BACKGROUND AND AIMS

NAD+ (nicotinamide adenine dinucleotide) is a cosubstrate of the sirtuins (SIRT) that are activated upon caloric restriction. Supplementing NAD+ precursors such as nicotinamide riboside (NR) has been reported to extend life span and combat metabolic syndrome through pan-sirtuin activation in mice. Notably, sirtuins compete with poly (ADP-ribose) polymerase (PARP)1 and CD38 for NAD+. Supplementing NAD+ precursors did not improve cardiovascular outcome in the AIM-HIGH trial. Recently, the terminal NAD+ metabolite 4PY (N1-methyl-4-pyridone-3-carboxamide) was reported to increase inflammation and to be associated with cardiovascular risk. We aimed to investigate whether NR provides atheroprotection.

METHODS

8-week-old male apolipoprotein E (Apoe) knockout mice were fed for 12 weeks a high-cholesterol diet supplemented with three NR doses: NR-, NR+, and NR++. RAW264.7 mouse macrophages and bone marrow macrophages were stimulated with oxLDL and NR.

RESULTS

NR++ enhanced plaque lesions in aortic sinus sections and increased plasma levels of TNFα, IL-6, and LDL-cholesterol. Liver and plasma NAD+ concentrations remained unchanged, but the downstream metabolite 4PY increased. In liver lysates, SIRT1 and lipoprotein receptors were decreased and CD38 increased in NR++; cleaved PARP1 and total PARylation decreased upon NR supplementation. In oxLDL-treated macrophages, high NR levels increased CD38 and CD86 expression.

CONCLUSIONS

High-dose NR supplementation in mice did not decrease but increase both aortic plaque lesions and systemic inflammation. These effects may be mediated by increased CD38 expression in macrophages, with NAD+ metabolism shifted from sirtuins towards CD38 and PARP1 pathways. Caution should be applied with presumed NAD+ boosters in patients with atherosclerosis.

Oxidant-Based Cytotoxic Agents During Aging: From Disturbed Energy Metabolism to Chronic Inflammation and Disease Progression

In humans, aging is an inevitable consequence of diminished growth processes after reaching maturity. The high order of biomolecules in cells and tissues is continuously disturbed by numerous physical and chemical destructive impacts. Host-derived oxidant-based cytotoxic agents (reactive species, transition free metal ions, and free heme) contribute considerably to this damage. These agents are under the control of immediately acting antagonizing principles, which are important to ensure cell and tissue homeostasis. In this review, I apply the concept of host-derived cytotoxic agents and their interplay with antagonizing principles to the aging process. During aging, energy metabolism and the supply of tissues with dioxygen and nutrients are increasingly disturbed. In addition, a chronic inflammatory state develops, a condition known as inflammaging. The balance between oxidant-based cytotoxic agents and protective mechanisms is analyzed depending on age-based physiological alterations in ATP production. Disturbances in this balance are associated with the development of age-related diseases and comorbidities. An enhanced production of reactive species from dysfunctional mitochondria, alterations in cellular redox homeostasis, and adaptations to hypoxia are highlighted. Examples of how disturbances between oxidant-based cytotoxic agents and antagonizing principles contribute to the pathogenesis of diseases in persons of advanced age are given.

Phytoestrogens and Sirtuin Activation for Renal Protection: A Review of Potential Therapeutic Strategies

Significant health and socio-economic challenges are posed by renal diseases, leading to millions of deaths annually. The costs associated with treating and caring for patients with renal diseases are considerable. Current therapies rely on synthetic drugs that often come with side effects. However, phytoestrogens, natural compounds, are emerging as promising renal protective agents. They offer a relatively safe, effective, and cost-efficient alternative to existing therapies. Phytoestrogens, being structurally similar to 17-β-estradiol, bind to estrogen receptors and produce both beneficial and, in some cases, harmful health effects. The activation of sirtuins has shown promise in mitigating fibrosis and inflammation in renal tissues. Specifically, SIRT1, which is a crucial regulator of metabolic activities, plays a role in protecting against nephrotoxicity, reducing albuminuria, safeguarding podocytes, and lowering reactive oxygen species in diabetic glomerular injury. Numerous studies have highlighted the ability of phytoestrogens to activate sirtuins, strengthen antioxidant defense, and promote mitochondrial biogenesis, playing a vital role in renal protection during kidney injury. These findings support further investigation into the potential role of phytoestrogens in renal protection. This manuscript reviews the potential of phytoestrogens such as resveratrol, genistein, coumestrol, daidzein, and formononetin in regulating sirtuin activity, particularly SIRT1, and thereby providing renal protection. Understanding these mechanisms is crucial for designing effective treatment strategies using naturally occurring phytochemicals against renal diseases.

Design, synthesis, and biological evaluation of novel artemisinin-based HDAC inhibitors with antitumor and antimalarial activities

In addition to the clinical applications as antimalarial agents, artemisinin and its derivatives have demonstrated significant potential in antitumor drug discovery. To enhance antitumor activity, a novel series of artemisinin-containing histone deacetylase (HDAC) inhibitors was designed using a hybrid strategy that fused the artemisinin moiety with HDAC inhibitory functionality. A triazole ring was incorporated into the linker region to improve water solubility. Among these derivatives, compound Hj-9 exhibited broad spectrum and especially potent antitumor activity against acute myelogenous leukemia cells MV4-11 (IC50 = 0.38 μM). Mechanism studies revealed that Hj-9 effectively arrests the cancer cell cycle at the G0/G1 phase and exhibits significant antiangiogenic activity. Further investigation demonstrated that Hj-9 induces cell autophagy, apoptosis, and mitochondrial membrane potential changes. Enzyme inhibitory activities against HDAC isoforms indicated that Hj-9 broadly inhibits multiple HDAC subtypes, especially showing particularly good inhibition of HDAC6. Furthermore, the antimalarial evaluation revealed derivatives Hj-1, Hj-2 and Hj-9 showed good antimalarial activity.

Effects of Aging on Glucose and Lipid Metabolism in Mice

Aging is accompanied by multiple molecular changes that contribute to aging associated pathologies, such as accumulation of cellular damage and mitochondrial dysfunction. Tissue metabolism can also change with age, in part, because mitochondria are central to cellular metabolism. Moreover, the cofactor NAD+, which is reported to decline across multiple tissues during aging, plays a central role in metabolic pathways such as glycolysis, the tricarboxylic acid cycle, and the oxidative synthesis of nucleotides, amino acids, and lipids. To further characterize how tissue metabolism changes with age, we intravenously infused [U-13C]-glucose into young and old C57BL/6J, WSB/EiJ, and diversity outbred mice to trace glucose fate into downstream metabolites within plasma, liver, gastrocnemius muscle, and brain tissues. We found that glucose incorporation into central carbon and amino acid metabolism was robust during healthy aging across these different strains of mice. We also observed that levels of NAD+, NADH, and the NAD+/NADH ratio were unchanged in these tissues with healthy aging. However, aging tissues, particularly brain, exhibited evidence of upregulated fatty acid and sphingolipid metabolism reactions that regenerate NAD+ from NADH. These data suggest that NAD+-generating lipid metabolism reactions may help to maintain the NAD+/NADH ratio during healthy aging.

Fine Particulate Matter (PM2.5) and the Blood-Testis Barrier: An in Vivo and in Vitro Mechanistic Study

BACKGROUND

Fine particulate matter [particulate matter (PM) with aerodynamic diameter of ≤ 2.5 μ m (PM 2.5 )] is considered a major component of ambient PM. Exposure to PM 2.5 was shown to be associated with male reproductive system injury. Ferroptosis is regarded as an iron-dependent programmed cell death that is associated with the pathological process. It has been reported that SIRT1 has protective effects on the male reproductive system. However, the underlying mechanisms of exposure to PM 2.5 -induced testicular injury are still unexplored.

OBJECTIVES

In this study, we investigated the relationship between ferroptosis and male reproductive injury after exposure to PM 2.5 and the role of SIRT1/HIF-1 α signaling pathway in this process.

METHODS

We established a PM 2.5 exposure model in vivo and in vitro using Sertoli cell Sirt1 conditional knockout C57BL/6 (cKO) mice testes and primary Sertoli cells. Hematoxylin and eosin (H&E) staining were conducted to examine the histology of the mice testes. Sperm parameters and biotin tracer assay were conducted to evaluate the effects of exposure to PM 2.5 on the mice testes. Related markers and genes related to the blood-testis barrier (BTB) and ferroptosis were measured by quantitative real-time polymerase chain reaction (qPCR), western blot, and immunofluorescence assay. siRNA transfection was used to evaluate the potential mechanism.

RESULTS

Significant pathological damage and lower sperm quality were detected in mice testes exposed to PM 2.5 . We found that exposure to PM 2.5 damaged the BTB and inhibited the expression level of the BTB-related proteins (including Connexin 43, Occludin, Claudin 11, N-Cadherin and ZO-1). According to the enrichment analysis results, ferroptosis and HIF-1 α signaling pathway were significantly enriched in mice testes and primary Sertoli cells exposed to PM 2.5 . Subsequent experiments were conducted to verify the results of the enrichment analysis and revealed differences in the expression levels of HIF-1 α , ferroptosis-related genes (including GPX4, SLC7A11, ACSL4, and HO-1) and ferroptosis-related markers [including malondialdehyde (MDA), glutathione (GSH), and Fe 2 + ], associated with lower expression of SIRT1 after exposure to PM 2.5 . These results suggest that PM 2.5 exposure may be associated with ferroptosis and HIF-1 α signaling pathway in male reproductive dysfunction.

CONCLUSIONS

Taken together, in vivo and in vitro experiments verified that PM 2.5 exposure in mice may lead to testicular dysfunction through new pathways. https://doi.org/10.1289/EHP14447.

Sirtuins and Resveratrol in Cardiorenal Diseases: A Narrative Review of Mechanisms and Therapeutic Potential

Aging is a very complex process, and it has been linked with Sirtuins. Sirtuin enzymes are a family of deacetylases that are related to caloric restriction and aging by modulating energy metabolism, genomic stability, and stress resistance. Up to now, seven sirtuins have been recognized. This narrative review aimed to analyze the literature produced between January 2005 and March 2025 to evaluate the role of sirtuins in chronic kidney disease and, as heart and kidney diseases are strictly interrelated, to explore their role in heart diseases and cardio-renal cross-talk. A reciprocal relationship between CKD and aging seems to exist since CKD may contribute to premature biological aging of different organ systems. SIRTs are involved in the pathophysiology of renal diseases; their activation can delay the progression of several renal diseases. Notably, an increasing number of studies linked SIRTs with different CVDs. SIRTs affect the production of mitochondrial reactive oxygen species (ROS) by modulating mitochondrial function. The imbalance of SIRT levels may increase the vulnerability to CVDs. SIRTs are involved in the pathophysiological mechanisms of HFpEF (heart failure with preserved ejection fraction) through different signaling pathways. Fibrosis is the linkage mechanism between the heart and kidney in the development of cardio-renal diseases. Current studies on sirtuins, resveratrol, and cardiorenal disease highlight their potential therapeutic benefits in regulating blood pressure, kidney function, lipid profiles, and inflammation, making them a promising area of investigation for improving cardiovascular and renal health outcomes. However, significant gaps remain. The limited availability of highly selective and potent sirtuin modulators hampers their clinical translation, as most existing compounds exhibit poor bioavailability and suboptimal pharmacokinetic properties.

Crosstalk between metabolism and epigenetics during macrophage polarization

Macrophage polarization is a dynamic process driven by a complex interplay of cytokine signaling, metabolism, and epigenetic modifications mediated by pathogens. Upon encountering specific environmental cues, monocytes differentiate into macrophages, adopting either a pro-inflammatory (M1) or anti-inflammatory (M2) phenotype, depending on the cytokines present. M1 macrophages are induced by interferon-gamma (IFN-γ) and are characterized by their reliance on glycolysis and their role in host defense. In contrast, M2 macrophages, stimulated by interleukin-4 (IL-4) and interleukin-13 (IL-13), favor oxidative phosphorylation and participate in tissue repair and anti-inflammatory responses. Metabolism is tightly linked to epigenetic regulation, because key metabolic intermediates such as acetyl-coenzyme A (CoA), α-ketoglutarate (α-KG), S-adenosylmethionine (SAM), and nicotinamide adenine dinucleotide (NAD+) serve as cofactors for chromatin-modifying enzymes, which in turn, directly influences histone acetylation, methylation, RNA/DNA methylation, and protein arginine methylation. These epigenetic modifications control gene expression by regulating chromatin accessibility, thereby modulating macrophage function and polarization. Histone acetylation generally promotes a more open chromatin structure conducive to gene activation, while histone methylation can either activate or repress gene expression depending on the specific residue and its methylation state. Crosstalk between histone modifications, such as acetylation and methylation, further fine-tunes macrophage phenotypes by regulating transcriptional networks in response to metabolic cues. While arginine methylation primarily functions in epigenetics by regulating gene expression through protein modifications, the degradation of methylated proteins releases arginine derivatives like asymmetric dimethylarginine (ADMA), which contribute directly to arginine metabolism-a key factor in macrophage polarization. This review explores the intricate relationships between metabolism and epigenetic regulation during macrophage polarization. A better understanding of this crosstalk will likely generate novel therapeutic insights for manipulating macrophage phenotypes during infections like tuberculosis and inflammatory diseases such as diabetes.

SIRT7 Is a Lysine Deacylase with a Preference for Depropionylation and Demyristoylation

Sirtuins are nicotinamide adenine dinucleotide (NAD+)-dependent deacylases that remove acyl groups from lysine residues on target proteins, releasing nicotinamide. SIRT7 is associated with aging and a number of age-related diseases, but the enzymatic properties of SIRT7 are largely unknown. In the present study, we investigated the biochemical activity of SIRT7 by performing a series of in vitro kinetic studies in the presence of different acyl substrates. The binding affinity of SIRT7 for NAD+ was dependent on the acyl substrate, and SIRT7 showed a preference for depropionylation and demyristoylation. Nicotinamide, the end-product of the sirtuin reaction, inhibits the activity of SIRT1-6. We also found that the sensitivity of SIRT7 to nicotinamide inhibition also depended on the chain length of the acylated peptides and that nicotinamide was a poor inhibitor of SIRT7 with non-acetylated substrates. These findings may provide insights into the development of novel SIRT7 modulators for the treatment of age-related diseases.

Impact of Resveratrol Supplementation on Human Sirtuin 1: A Grading of Recommendations Assessment, Development and Evaluation-Assessed Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Resveratrol, a natural polyphenol compound, possesses anti-aging, antitumor, and vascular protective properties. These attributes are believed to stem from its influence on Sirtuin 1 (Sirt1), a member of the human Sirtuin family and a nicotinamide adenine dinucleotide-dependent histone deacetylase.

OBJECTIVE

The aim of this study was to quantitatively investigate the impact of resveratrol supplementation on Sirt1 levels in adults by conducting a systematic review and meta-analysis of randomized controlled trials (RCTs) involving resveratrol supplementation.

METHODS

This Grading of Recommendations Assessment, Development and Evaluation-assessed systematic review involved a comprehensive search of PubMed, Embase, MEDLINE, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar databases using related keywords and was conducted from March 14, 2024, to April 15, 2024, to identify all RCTs investigating resveratrol's effects on Sirt1. Effect sizes were quantified as mean differences (MDs) or standardized mean differences (SMDs), with standard deviations of outcomes. An overall effect estimate was derived using a random-effects model when 2 or more studies reported similar outcomes. Statistical heterogeneity was assessed through the calculation of I2 statistics. In addition, a dose-response analysis was performed to assess potential dose-response relationships. Risk of bias was assessed using the Cochrane risk-of-bias tool for RCTs (RoB 2). Publication bias was evaluated using Begg's test and a meta-regression using the year of publication as a moderator.

RESULTS

Eleven RCTs examining the effects of resveratrol on Sirt1 gene expression (4 RCTs), protein expression (5 RCTs), and serum levels (3 RCTs) were included in the meta-analysis. The results showed no significant impact of resveratrol on Sirt1 gene expression (SMD = 0.05; 95% CI -0.24 to 0.344; P = .73), protein expression (SMD = 0.3; 95% CI -0.15 to 0.77; P = .18), or serum levels (MD = -0.04; 95% CI -0.235 to 0.16; P = .7). However, subgroup analyses suggested a significant increase in Sirt1 gene expression in studies with an intervention duration of <12 weeks and evaluating blood tissue. Furthermore, the impact of resveratrol on Sirt1 appeared to be influenced by the dosage regimen, with a significant effect for intervention duration.

CONCLUSIONS

Study results indicate that resveratrol supplementation does not significantly influence human Sirt1 based on the overall meta-analysis. However, the dose-response analysis suggests that the effect of resveratrol on Sirt1 depends on the dosage regimen.

Role of Protein Lysine Acetylation in the Pathogenesis and Treatment of Obesity and Metabolic Syndrome

PURPOSE OF REVIEW

This review aimed to highlight the known role of histone deacetylases (HDACs) and lysine acetyltransferases (KATs) in individuals with obesity, better understand the role of HDACs and KATs enzymes in obesity and related metabolic disorders.

RECENT FINDINGS

Numerous cellular activities, including DNA replication, DNA repair, cell cycle regulation, RNA splicing, signal transmission, metabolic function, protein stability, transportation, and transcriptional regulation, are influenced by lysine acetylation. Protein lysine acetylation serves several purposes, which not only contribute to the development of metabolic disorders linked to obesity but also hold promise for therapeutic approaches. The current study demonstrates that HDACs and KATs control lysine acetylation. This review details the advancements made in the study of obesity, related metabolic diseases, and protein lysine acetylation. It contributes to our understanding of the function and mechanism of protein lysine acetylation in obesity and MS and offers a fresh method for treating these diseases.

Chlorogenic acid attenuates pyrrolizidine alkaloid-induced liver injury through modulation of the SIRT1/FXR signaling pathway

BACKGROUND

Pyrrolizidine alkaloids (PAs), recognized globally for their hepatotoxic properties, significantly contribute to liver damage through an imbalance in bile acid homeostasis. Addressing this imbalance is crucial for therapeutic interventions in PA-related liver injuries. Chlorogenic acid (Cga), a phenolic compound derived from medicinal plants, has demonstrated hepato-protective effects across a spectrum of liver disorders. The specific influence and underlying mechanisms by which Cga mitigates PA-induced liver damage have not been clearly defined.

MATERIALS AND METHODS

To explore the protective effects of Cga against acute PA toxicity, a murine model was established. The influence of Cga on bile acid metabolism was confirmed through a variety of molecular biology techniques. These included RNA sequencing, western blotting, and immunoprecipitation, along with quantitative analyses of bile acid concentrations.

RESULTS

Our findings indicate that Cga enhances sirtuin 1 (SIRT1) activation and increases farnesoid X receptor (FXR) signaling, which are crucial for maintaining bile acid balance in PA-induced hepatic injury. When mice subjected to PA-induced hepatic injury were treated with SIRT1 inhibitors alongside Cga, the hepatoprotective effects of Cga were significantly reduced. In Fxr-KO mice, the ability of Cga to mitigate liver damage induced by PAs was substantially reduced, which underscores the role of the SIRT1/FXR signaling axis in mediating the protective effects of Cga.

CONCLUSION

Our research suggests that Cga can serve as an effective treatment for PA-mediated hepatotoxicity. It appears that influencing the SIRT1/FXR signaling pathway might provide an innovative pharmacological approach to address liver damage caused by PAs.

Phosphorylation of an RNA-Binding Protein Rck/Me31b by Hippo Is Essential for Adipose Tissue Aging

The metazoan lifespan is determined in part by a complex signaling network that regulates energy metabolism and stress responses. Key signaling hubs in this network include insulin/IGF-1, AMPK, mTOR, and sirtuins. The Hippo/Mammalian Ste20-like Kinase1 (MST1) pathway has been reported to maintain lifespan in Caenorhabditis elegans, but its role has not been studied in higher metazoans. In this study, we report that overexpression of Hpo, the MST1 homolog in Drosophila melanogaster, decreased lifespan with concomitant changes in lipid metabolism and aging-associated gene expression, while RNAi Hpo depletion increased lifespan. These effects were mediated primarily by Hpo-induced transcriptional activation of the RNA-binding protein maternal expression at 31B (Me31b)/RCK, resulting in stabilization of mRNA-encoding a lipolytic hormone, Akh. In mouse adipocytes, Hpo/Mst1 mediated adipocyte differentiation, phosphorylation of RNA-binding proteins such as Rck, decapping MRNA 2 (Dcp2), enhancer Of MRNA decapping 3 (Edc3), nucleolin (NCL), and glucagon mRNA stability by interacting with Rck. Decreased lifespan in Hpo-overexpressing Drosophila lines required expression of Me31b, but not DCP2, which was potentially mediated by recovering expression of lipid metabolic genes and formation of lipid droplets. Taken together, our findings suggest that Hpo/Mst1 plays a conserved role in longevity by regulating adipogenesis and fatty acid metabolism.

Research on the mechanism of resistance exercise in promoting glucose metabolic shift to regulate muscle satellite cell proliferation in type 2 diabetic rats

Skeletal muscle atrophy is a common complication in patients with type 2 diabetes (T2D) and is associated with dysfunction of muscle satellite cells. The activation and proliferation of muscle satellite cells involve a switch in glucose metabolism, which is regulated by driving the acetylation of histones to control the expression of related genes. Studies have confirmed that resistance exercise can improve insulin resistance and activate muscle satellite cells, but the specific molecular mechanisms are not yet clear. This study aims to investigate whether resistance exercise can promote the proliferation of muscle satellite cells and improve muscle atrophy in type 2 diabetic rats by enhancing glucose metabolism in skeletal muscles. A T2D rat model was induced by combining a high-fat diet with streptozotocin injection. After 8 weeks of resistance exercise, the activity of key enzymes (Pyruvate Kinase, Phosphofructokinase, Pyruvate Dehydrogenase) in glucose metabolism in the skeletal muscles of T2D rats significantly increased, the expression of Sirtuin 1 (Sirt1) and Nicotin -amide Phosphoribosyltransferase (Nampt) in the skeletal muscles of the rats decreased, and the expression of acetylation of lysine 16 on histone H4 (H4K16ac) significantly increased, indicating an elevated level of the H4K16ac. The expression of paired box 7 (Pax7) and myogenic differentiation (MyoD) was significantly upregulated, indicating that exercise promoted the proliferation of muscle satellite cells. These results suggest that resistance exercise may promote glucose metabolism in skeletal muscles of T2D rats by regulating the activity of key enzymes in sugar metabolism, further regulating Sirt1-mediated histone H4K16ac, thereby promoting the proliferation of muscle satellite cells and improving muscle atrophy.

Lactate improves postoperative cognitive function through attenuating oxidative stress and neuroinflammation in aged mice via activating the SIRT1 pathway

Postoperative cognitive dysfunction (POCD) is a recognized clinical phenomenon characterized by cognitive impairment in patients following anesthesia and surgery, especially in the elderly. However, the pathogenesis of POCD remains unclear. In the last decades, lactate's neuroprotective properties have been increasingly mentioned. The study tested the hypothesis that lactate may attenuate the cognitive impairment induced by anesthesia and surgery in aged mice through SIRT1-dependent antioxidant and anti-inflammatory effects. We used 18-month-old C57BL/6 mice to establish the POCD animal model by exploratory laparotomy with isoflurane anesthesia. For the interventional study, mice were administered lactate, with or without the potent and selective SIRT1 inhibitor EX-527. Behavioral tests including open field (OF), Y maze and fear conditioning (FC) tests were performed from 4 to 7 days after anesthesia and surgery. Immunofluorescence staining and Western blot were employed to assess oxidative damage, activation of microglia and astrocytes, levels of proinflammatory cytokines, and the expression of plasticity-related proteins. Lactate treatment can ameliorate oxidative stress, neuroinflammation, and the decreased levels of plasticity-related proteins induced by anesthesia and surgery, ultimately improving cognitive impairment in aged mice. However, co-treatment with lactate and EX-527 diminished the beneficial effects. Our study indicates that the mechanisms underlying neuroprotective properties of lactate might be related to its antioxidant and anti-inflammatory effects, and improvement of hippocampal synaptic plasticity through activation of SIRT1 pathway.

Evaluating the effects of zinc oxide nanoparticles on a sentinel aquatic invertebrate species: Transcriptomic analysis and potential implications for ecosystem health

The widespread use of zinc oxide nanoparticles (ZnO NPs) in various products raises significant ecological concerns due to their potential toxic effects in aquatic environments. This study employed the Asian green mussel (Perna viridis) as a model to explore the molecular and ecological risks of ZnO NP exposure using transcriptomics. Mussels exposed to ZnO NPs (5, 10, and 15 mg/L) for 28 days showed significant gene expression changes in gill tissues, affecting immune response, calcium homeostasis, and cellular stress. Disrupted pathways such as FOXO, Wnt, and TGFβ reveal complex toxicity mechanisms. These findings provide crucial insights into the environmental impact of nanoparticle pollution, emphasizing the need for stringent regulations. Furthermore, the shared molecular pathways suggest that similar mechanisms may occur in humans, highlighting potential health risks associated with nanoparticle exposure.

Islet-derived exosomal miR-204 accelerates insulin resistance in skeletal muscle by suppressing sirtuin 1: An in vivo study in a mouse model of high-fat diet-induced obesity

AIMS

The interaction between pancreatic islets and skeletal muscle plays a pivotal role in the development of insulin resistance. The present study aimed to elucidate the impact of non-hormonal molecules from islets on the insulin sensitivity of skeletal muscle cells.

MATERIALS AND METHODS

We developed a mouse model of obesity through a high-fat diet, assessing glucose tolerance and conducting miRNA sequencing on skeletal muscle samples. An in vitro model was established by treating cells with palmitic acid, and exosomes in the supernatant were characterized using scanning electron microscopy and CD63 expression analysis. Intracellular miR-204-5p levels were quantified by RT-PCR.

RESULTS

Our in vivo model demonstrated a robust correlation between miR-204-5p level alterations and obesity-induced insulin resistance. Elevated fatty acid levels were observed to increase miR-204-5p in both skeletal muscle and islets. In cellular studies, palmitic acid increased miR-204-5p in MIN-6 islet β-cells but not in C2C12 skeletal muscle cells. Exosomes containing miR-204-5p, secreted by palmitic acid-treated MIN6 cells, were identified through morphological examination, immunoblotting for the exosomal marker CD63, and intraexosomal miR-204-5p level measurement. C2C12 cells were shown to uptake islet-derived miR-204-5p exosomes, as evidenced by the uptake of Exo-Red labeled exosomes. TargetScan analysis identified a highly conserved binding site for miR-204-5p in the 3' UTR of Sirt mRNA. Functional studies indicated that miR-204-5p overexpression reduced glucose consumption and uptake in C2C12 cells, decreased Sirt expression, and impaired insulin signaling, as evidenced by reduced Akt phosphorylation and membrane Glut4 levels.

CONCLUSIONS

Our findings reveal that miR-204-5p contributes to the development of insulin resistance in obesity and acts as a signaling molecule in the crosstalk between pancreatic islets and skeletal muscle.

In silico approach reveals N-(5-phenoxythiophen-2-yl)-2-(arylthio)acetamides as promising selective SIRT2 inhibitors: the case of structural optimization of virtual screening-derived hits

Epigenetic modifications play an essential role in tumor suppression and promotion. Among the diverse range of epigenetic regulators, SIRT2, a member of NAD+-dependent protein deacetylates, has emerged as a crucial regulator of cellular processes, including cell cycle progression, DNA repair, and metabolism, impacting tumor growth and survival. In the present work, a series of N-(5-phenoxythiophen-2-yl)-2-(arylthio)acetamide derivatives were identified following a structural optimization of previously reported virtual screening hits, accompanied by enhanced SIRT2 inhibitory potency. Among the compounds, ST44 and ST45 selectively inhibited SIRT2 with IC50 values of 6.50 and 7.24 μM, respectively. The predicted binding modes of the two compounds revealed the success of the optimization run. Moreover, ST44 displayed antiproliferative effects on the MCF-7 human breast cancer cell line. Further, the contribution of SIRT2 inhibition in this effect of ST44 was supported by western blotting, affording an increased α-tubulin acetylation. Furthermore, molecular dynamics (MD) simulations and binding free energy calculations using molecular mechanics/generalized born surface area (MM-GBSA) method evaluated the accuracy of predicted binding poses and ligand affinities. The results revealed that ST44 exhibited a remarkable level of stability, with minimal deviations from its initial docking conformation. These findings represented a significant improvement over the virtual screening hits and may contribute substantially to our knowledge for further selective SIRT2 drug discovery.Communicated by Ramaswamy H. Sarma.

Sirtuins as therapeutic targets in diabetes

INTRODUCTION

Sirtuins (SIRTs) are NAD+-dependent deacetylases that mediate post-translational modifications of proteins. Seven members of the SIRT family have been identified in mammals. Importantly, SIRTs interact with numerous metabolic and inflammatory pathways. Thus, researchers have investigated their role in metabolic and inflammatory disorders.

AREAS COVERED

In this review, we comprehensively discuss the involvement of SIRTs in the processes of pancreatic β-cell dysfunction, glucose tolerance, insulin secretion, lipid metabolism, and adipocyte functions. In addition, we describe the current evidence regarding modulation of the expression and activity of SIRTs in diabetes, diabetic complications, and obesity.

EXPERT OPINION

The development of specific SIRT activators and inhibitors that exhibit high selectivity toward specific SIRT isoforms remains a major challenge. This involves the need to elucidate the physiological pathways involving SIRTs, as well as their important role in the development of metabolic disorders. Molecular modeling techniques will be helpful to develop new compounds that modulate the activity of SIRTs, which may contribute to the preparation of new drugs that selectively target specific SIRTs. SIRTs hold promise as potential targets in metabolic disease, but there is much to learn about specific modulators and the final answers will await clinical trials.

Role of sirtuin 1 in depression‑induced coronary heart disease: Molecular pathways and therapeutic potential (Review)

Depression and coronary heart disease (CHD) are two interconnected diseases that profoundly impact global health. Depression is both a complex psychiatric disorder and an established risk factor for CHD. Sirtuin 1 (SIRT1) is an enzyme that requires the cofactor nicotinamide adenine dinucleotide (NAD+) to perform its deacetylation function, and its involvement is crucial in reducing cardiovascular risks that are associated with depression. SIRT1 exerts its cardioprotective effects via modulating oxidative stress, inflammation and metabolic processes, all of which are central to the pathogenesis of CHD in individuals with depression. Through influencing these pathways, SIRT1 helps to reduce endothelial dysfunction, prevent the formation of atherosclerotic plaques and stabilize existing plaques, thereby decreasing the overall risk of CHD. The present review underscores the important role of SIRT1 in serving as a therapeutic intervention molecule for tackling cardiovascular complications stemming from depression. Furthermore, it highlights the need for further studies to clarify how SIRT1 influences both depression and CHD at the molecular level. The ultimate goal of this research will be to translate these findings into practical clinical intervention strategies.

Multiple omics analysis reveals the regulation of SIRT4 on lipid deposition and metabolism during the differentiation of bovine preadipocytes

The differentiation and lipid metabolism of preadipocytes are crucial processes in IMF deposition. Studies have demonstrated that SIRT4 plays essential roles in energy metabolism and redox homeostasis, with its expression being coordinately regulated by multiple transcription factors associated with energy and lipid metabolism. In this study, the findings of multiple omics analysis reveal that SIRT4 significantly up-regulates the expression of genes involved in adipogenesis and enhances the differentiation and lipid deposition of bovine preadipocytes. Furthermore, SIRT4 profoundly influences the expression pattern of metabolites by increasing the abundance of substances involved in lipid synthesis while decreasing those that promote lipid oxidative decomposition. Additionally, SIRT4 broadly up-regulates the expression levels of various lipid classes, including glycerolipids, glycerophospholipids, sphingolipids, and sterol lipids. These findings not only provide a theoretical basis for molecular breeding and genetic improvement in beef cattle, but also offer potential therapeutic approaches for energy homeostasis disorders and obesity.

Caloric Restriction Attenuated Nerve Damages Mediated Through SIRT-1-a Study Using Nerve Crush Injury Model in Rats

Activation of Sirtuin 1 (SIRT-1) is vital for axonogenesis and nerve regeneration. Caloric restriction (CR) has health benefits and protects against neurodegenerative disorders, largely through SIRT-1 regulation. This study investigates how diet control impacts peripheral nerve injury, focusing on SIRT-1 expression. We prepared nerve tissue cultures for a pharmacological analysis of SIRT-1's effects on nerve degeneration. After two weeks of 70% caloric restriction, we crushed the left sciatic nerve of Sprague-Dawley rats with a vessel clamp. We then administered SIRT-1 agonists or antagonists intraperitoneally. Nerve explant cultures showed increased SIRT-1 expression with SRT-1720, which was reduced by EX527, indicating enhanced regeneration. In the animal study, diet control led to notable SIRT-1 expression in plasma. This expression increased with SIRT-1 agonists and decreased with antagonists. SIRT-1 levels in paw skin were strongly correlated with PGP 9.5 and collagen deposition, while nerve fiber size and regeneration markers (S-100 and NF) also correlated with SIRT-1 expression. Inflammatory markers showed an inverse relationship with SIRT-1. TNF-α and NGF in the dorsal root ganglion responded reciprocally to SIRT-1 expression. Increased acetylcholine receptors and desmin in denervated muscle were parallel to SIRT-1 levels, with similar trends observed in muscle weight and diameter. Neurobehavioral and electrophysiological results aligned with these measurements. Caloric restriction has a preventative effect on nerve damage, mainly through SIRT-1 modulation. From a health perspective, promoting caloric restriction is important for mitigating nerve injury severity.

Energy metabolism in health and diseases

Energy metabolism is indispensable for sustaining physiological functions in living organisms and assumes a pivotal role across physiological and pathological conditions. This review provides an extensive overview of advancements in energy metabolism research, elucidating critical pathways such as glycolysis, oxidative phosphorylation, fatty acid metabolism, and amino acid metabolism, along with their intricate regulatory mechanisms. The homeostatic balance of these processes is crucial; however, in pathological states such as neurodegenerative diseases, autoimmune disorders, and cancer, extensive metabolic reprogramming occurs, resulting in impaired glucose metabolism and mitochondrial dysfunction, which accelerate disease progression. Recent investigations into key regulatory pathways, including mechanistic target of rapamycin, sirtuins, and adenosine monophosphate-activated protein kinase, have considerably deepened our understanding of metabolic dysregulation and opened new avenues for therapeutic innovation. Emerging technologies, such as fluorescent probes, nano-biomaterials, and metabolomic analyses, promise substantial improvements in diagnostic precision. This review critically examines recent advancements and ongoing challenges in metabolism research, emphasizing its potential for precision diagnostics and personalized therapeutic interventions. Future studies should prioritize unraveling the regulatory mechanisms of energy metabolism and the dynamics of intercellular energy interactions. Integrating cutting-edge gene-editing technologies and multi-omics approaches, the development of multi-target pharmaceuticals in synergy with existing therapies such as immunotherapy and dietary interventions could enhance therapeutic efficacy. Personalized metabolic analysis is indispensable for crafting tailored treatment protocols, ultimately providing more accurate medical solutions for patients. This review aims to deepen the understanding and improve the application of energy metabolism to drive innovative diagnostic and therapeutic strategies.

The promise of mitochondria in the treatment of glioblastoma: a brief review

Glioblastoma (GBM) is a prevalent and refractory type of brain tumor. Over the past two decades, there have been minimal advancements in GBM therapy. The current standard treatment involves surgical excision followed by radiation and chemotherapy. Compared to other tumors, GBM is more challenging to treat due to the presence of glioma stem-like cells (GSCs) and the blood-brain barrier, resulting in an extremely low survival rate. Mitochondria play a critical role in tumor respiration, metabolism, and multiple signaling pathways involved in tumor formation, progression, and cell apoptosis. Consequently, mitochondria represent promising targets for developing novel anticancer agents, including those targeting oxidative phosphorylation, reactive oxygen species (ROS), mitochondrial transfer, and mitophagy. This review outlines the mitochondrial-related therapeutic targets in GBM, highlighting the potential of mitochondria as a target for GBM treatment.

Metabolic reprogramming in the spinal cord drives the transition to pain chronicity

Acute injuries can progress into painful states that endure long after healing. The mechanism underlying this transition remains unclear, but metabolic adaptations to the bioenergy demands imposed by injury are plausible contributors. Here we show that peripheral injury activates AKT/mTORC1 in afferent segments of the mouse spinal cord, redirecting local core metabolism toward biomass production while simultaneously suppressing autophagy-mediated biomass reclamation. This metabolic shift supports neuroplasticity, but creates a resource bottleneck that depletes critical spinal cord nutrients. Preventing this depletion with a modified diet normalizes biomass generation and autophagy and halts the transition to chronic pain. This effect, observed across multiple pain models, requires activation of the nutrient sensors, sirtuin-1 and AMPK, as well as restoration of autophagy. The findings identify metabolic reprogramming as a key driver of the progression to pain chronicity and point to nutritional and pharmacological interventions that could prevent this progression after surgery or other physical traumas.

Sirtuin1 in Spinal Cord Injury: Regulatory Mechanisms, Microenvironment Remodeling and Therapeutic Potential

BACKGROUND

Spinal cord injury (SCI) is a complex central nervous system disorder characterized by multifaceted pathological processes, including inflammation, oxidative stress, programmed cell death, autophagy, and mitochondrial dysfunction. Sirtuin 1 (Sirt1), a critical NAD+-dependent deacetylase, has emerged as a promising therapeutic target for SCI repair due to its potential to protect neurons, regulate glial and vascular cells, and optimize the injury microenvironment. However, the regulatory roles of Sirt1 in SCI are complex and challenging, as its effects vary depending on activation timing, expression levels, and cell types.

METHODS

A systematic literature review was conducted using PubMed, Scopus, and Web of Science to identify studies investigating Sirt1 in SCI. Relevant publications were analyzed to synthesize current evidence on Sirt1's mechanisms, therapeutic effects, and challenges in SCI repair.

RESULTS

Sirt1 exerts broad regulatory effects across diverse pathological processes and cell types post-SCI. It promotes neuronal survival and axonal regeneration, modulates astrocytes and microglia to resolve inflammation, supports oligodendrocyte-mediated myelination, and enhances vascular endothelial function. Proper Sirt1 activation may mitigate secondary injury, whereas excessive or prolonged activation could impair inflammatory resolution or disrupt cellular homeostasis. This review highlights Sirt1 activation as potential therapies, but challenges include optimizing spatiotemporal activation and addressing dual roles in different cell types.

CONCLUSION

Targeting Sirt1 represents a viable strategy for SCI repair, given its multifaceted regulation of neuroprotection, immunomodulation, and tissue remodeling. However, translating these findings into therapies requires resolving critical issues such as cell type-specific delivery, precise activation timing, and dosage control. This review provides a theoretical foundation and practical insights for advancing Sirt1-based treatments for SCI.

Epigenetic Cross-Talk Between Sirt1 and Dnmt1 Promotes Axonal Regeneration After Spinal Cord Injury in Zebrafish

Though spinal cord injury (SCI) causes irreversible sensory and motor impairments in human, adult zebrafish retain the potent regenerative capacity by injury-induced proliferation of central nervous system (CNS)-resident progenitor cells to develop new functional neurons at the lesion site. The hallmark of SCI in zebrafish lies in a series of changes in the epigenetic landscape, specifically DNA methylation and histone modifications. Decoding the post-SCI epigenetic modifications is therefore critical for the development of therapeutic remedies that boost SCI recovery process. Here, we have studied on Sirtuin1 (Sirt1), a non-classical histone deacetylase that potentially plays a critical role in neural progenitor cells (NPC) proliferation and axonal regrowth following SCI in zebrafish. We investigated the role of Sirt1 in NPC proliferation and axonal regrowth in response to injury in the regenerating spinal cord and found that Sirt1 is involved in the induction of NPC proliferation along with glial bridging during spinal cord regeneration. We also demonstrate that Sirt1 plays a pivotal role in regulating the HIPPO pathway through deacetylation-mediated inactivation of Dnmt1 and subsequent hypomethylation of yap1 promoter, leading to the induction of ctgfa expression, which drives the NPC proliferation and axonal regrowth to complete the regenerative process. In conclusion, our study reveals a novel cross-talk between two important epigenetic effectors, Sirt1 and Dnmt1, in the context of spinal cord regeneration, establishing a previously undisclosed relation between Sirt1 and Yap1 which provides a deeper understanding of the underlying mechanisms governing injury-induced NPC proliferation and axonal regrowth. Therefore, we have identified Sirt1 as a novel, major epigenetic regulator of spinal cord regeneration by modulating the HIPPO pathway in zebrafish.

The Chemopreventive Effect of Ginsenoside Compound K Is Regulated by PARP-1 Hyperactivation, Which Is Promoted by p62-Dependent SIRT6 Degradation

BACKGROUND AND AIMS

Ginsenoside compound K (CK), a saponin metabolite of ginseng, exerts anticancer effects; however, its molecular mechanisms of action in lung cancer remain unclear. We investigated the involvement of silent information regulator 6 (SIRT6) and poly (ADP-ribose) polymerase 1 (PARP-1) in the anticancer effects of CK in lung cancer.

METHODS AND RESULTS

CK induced PARP-1 activation-mediated parthanatos via sequestosome-1/p62-mediated SIRT6 degradation and inhibited the proliferation of H460 cells. Although CK reduced procaspase-8 levels, no significant apoptotic cleavage of procaspase-3 or PARP-1 was observed. Furthermore, CK upregulated p27, p21, phospho-p53, and gamma-H2AX levels. CK increased LC3-II levels in a p62-independent manner, but p62 was upregulated by autophagy inhibition, indicating that p62 is involved in CK-induced autophagy. CK-treated cells showed typical features of parthanatos, including PARP-1 hyperactivation, intracellular redistribution of poly ADP-ribose and pro-apoptotic factors, and chromatin fragmentation. SIRT6 was degraded in a CK concentration- and time-dependent manner. SIRT6 protein was upregulated by PARP-1 inhibition, nicotinamide adenine dinucleotide (NAD)+ supplementation, antioxidants, and p62 knockdown, but was decreased by autophagy blockade. PARP-1 activation was negatively correlated with SIRT6 levels, indicating that SIRT6 and PARP-1 activation play complementary roles in CK-induced growth inhibition. Immunofluorescence staining, fractionation studies, and immunoprecipitation were used to confirm the colocalization and interaction between p62 and SIRT6.

CONCLUSIONS

PARP-1 activation is promoted by p62-mediated SIRT6 degradation, which plays an important role in CK-induced growth inhibition. Therefore, SIRT6 is a potential biomarker for the chemopreventive effect of CK in lung cancer cells, but further studies on SIRT6 are needed for the clinical application of CK.

ADSCs-derived exosomes suppress macrophage ferroptosis via the SIRT1/NRF2 signaling axis to alleviate acute lung injury in sepsis

Acute lung injury being one of the earliest and most severe complications during sepsis and macrophages play a key role in this process. To investigate the regulatory effects and potential mechanisms of adipose mesenchymal stem cell derived-exosomes (ADSC-exo) on macrophages and septic mice, ADSCs-exo was administrated to both LPS-induced macrophage and cecal ligation and puncture (CLP) induced sepsis mice. ADSCs-exo was confirmed to inhibit M1 polarization of macrophages and to reduce excessive inflammation. The use of ADSCs-exo in CLP mice and in LPS-induced macrophages relieved oxidative stress, cellular damage, and acute lung injury. During this process, ADSCs-exo increased the nuclear translocation of Nrf2, significantly upregulating the activation of the antioxidant pathway Nrf2/HO-1. Concurrently, they enhanced the expression of SIRT1 in macrophages. Further SIRT1 interference experiments demonstrated that ADSCs-exo mitigated macrophage inflammatory responses and LPS-induced ferroptosis by upregulating SIRT1. In the LPS-induced macrophage model, after SIRT1 was interfered with, ADSCs-exo failed to upregulate the Nrf2/HO-1 signaling pathway, leading to enhanced ferroptosis. Finally, in a CLP sepsis mouse model with myeloid-specific SIRT1 knockout, ADSCs-exo was observed to reduce lung tissue injury, oxidative stress damage, and ferroptosis. Still, these beneficial effects were reversed due to the myeloid-specific knockout of SIRT1, while co-administration of a ferroptosis inhibitor rescued this situation, alleviating lung injury and significantly reducing tissue levels of oxidative stress. In conclusion, this study elucidated a novel potential therapeutic mechanism wherein ADSCs-exo upregulates the levels of SIRT1 in macrophages through a non-delivery approach.

Sir2 and Fun30 regulate ribosomal DNA replication timing via MCM helicase positioning and nucleosome occupancy

The association between late replication timing and low transcription rates in eukaryotic heterochromatin is well known, yet the specific mechanisms underlying this link remain uncertain. In Saccharomyces cerevisiae, the histone deacetylase Sir2 is required for both transcriptional silencing and late replication at the repetitive ribosomal DNA (rDNA) arrays. We have previously reported that in the absence of SIR2, a de-repressed RNA PolII repositions MCM replicative helicases from their loading site at the ribosomal origin, where they abut well-positioned, high-occupancy nucleosomes, to an adjacent region with lower nucleosome occupancy. By developing a method that can distinguish activation of closely spaced MCM complexes, here we show that the displaced MCMs at rDNA origins have increased firing propensity compared to the nondisplaced MCMs. Furthermore, we found that both activation of the repositioned MCMs and low occupancy of the adjacent nucleosomes critically depend on the chromatin remodeling activity of FUN30. Our study elucidates the mechanism by which Sir2 delays replication timing, and it demonstrates, for the first time, that activation of a specific replication origin in vivo relies on the nucleosome context shaped by a single chromatin remodeler.

Effects of Astragaloside IV and Formononetin on Oxidative Stress and Mitochondrial Biogenesis in Hepatocytes

Over-accumulation of reactive oxygen species (ROS) causes hepatocyte dysfunction and apoptosis that might lead to the progression of liver damage. Sirtuin-3 (SIRT3), the main NAD+-dependent deacetylase located in mitochondria, has a critical role in regulation of mitochondrial function and ROS production as well as in the mitochondrial antioxidant mechanism. This study explores the roles of astragaloside IV (AST-IV) and formononetin (FMR) in connection with SIRT3 for potential antioxidative effects. It was shown that the condition of combined pre- and post-treatment with AST-IV or FMR at all concentrations statistically increased and rescued cell proliferation. ROS levels were not affected by pre-or post-treatment individually with AST-IV or pre-treatment with FMR; however, post-treatment with FMR resulted in significant increases in ROS in all groups. Significant decreases in ROS levels were seen when pre- and post-treatment with AST-IV were combined at 5 and 10 μM, or FMR at 5 and 20 μM. In the condition of combined pre- and post-treatment with 10 μM AST-IV, there was a significant increase in SOD activity, and the transcriptional levels of Sod2, Cat, and GPX1 in all treatment groups, which is indicative of reactive oxygen species detoxification. Furthermore, AST-IV and FMR activated PGC-1α and AMPK as well as SIRT3 expression in AML12 hepatocytes exposed to t-BHP-induced oxidative stress, especially at high concentrations of FMR. This study presents a novel mechanism whereby AST-IV and FMR yield an antioxidant effect through induction of SIRT3 protein expression and activation of an antioxidant mechanism as well as mitochondrial biogenesis and mitochondrial content and potential. The findings suggest these agents can be used as SIRT3 modulators in treating oxidative-injury hepatocytes.

Epigenetic Control of Redox Pathways in Cancer Progression

Significance: Growing evidence indicates the importance of redox reactions homeostasis, mediated predominantly by reactive oxygen species (ROS) in influencing the development, differentiation, progression, metastasis, programmed cell death, tumor microenvironment, and therapeutic resistance of cancer. Therefore, reviewing the ROS-linked epigenetic changes in cancer is fundamental to understanding the progression and prevention of cancer. Recent Advances: We review in depth the molecular mechanisms involved in ROS-mediated epigenetic changes that lead to alteration of gene expression by altering DNA, modifying histones, and remodeling chromatin and noncoding RNA. Critical Issues: In cancerous cells, alterations of the gene-expression regulatory elements could be generated by the virtue of imbalance in tumor microenvironment. Various oxidizing agents and mitochondrial electron transport chain are the major pathways that generate ROS. ROS plays a key role in carcinogenesis by activating pro-inflammatory signaling pathways and DNA damage. This loss of ROS-mediated epigenetic regulation of the signaling pathways may promote tumorigenesis. We address all such aspects in this review. Future Directions: Developments in this growing field of epigenetics are expected to contribute to further our understanding of human health and diseases such as cancer and to test the clinical applications of redox-based therapy. Recent studies of the cancer-epigenetic landscape have revealed pervasive deregulation of the epigenetic factors in cancer. Thus, the study of interaction between ROS and epigenetic factors in cancer holds a great promise in the development of effective and targeted treatment modalities. Antioxid. Redox Signal. 00, 000-000.

Enhancing porcine oocyte quality and embryo development through natural antioxidants

During fetal development, primordial oocytes maintain their developmental potential through a ROS-minimizing metabolic mechanism. Maturation increases ROS levels, causing stress and damage, which are countered by in vivo antioxidants. In vitro maturation (IVM) worsens this due to fewer antioxidant presence and medium factors. To address this, we evaluated the effects of incorporating various natural antioxidants in the porcine oocyte IVM media. Our findings revealed that 10 μM Dendrobine (DEN), 1 μM Polydatin (PD), 20 μM Limonin (LIM), and 25 μM Nobiletin (NOB) significantly improved the first polar body extrusion rates (p < 0.05), reduced ROS, and increased GSH levels. Individual addition of 100 μg/mL Lycium barbarum polysaccharides (LBP), 0.1 μM Kaempferol (KAE), 250 μM Salidroside (SAL), 10 μM Curcumin (CUR), DEN, PD, LIM, and NOB to the porcine IVM system showed that KAE, LIM, NOB, and LBP treatments yielded the most favorable results. At the gene level, LIM, LBP, and NOB were found to upregulate the expression levels of GPX1, SIRT1, and TFAM, while downregulating Caspase3 and increasing the BCL2/BAX ratio. The inclusion of LIM, NOB, and LBP, either alone or in combination, into the IVM media effectively alleviated oxidative stress in porcine oocytes, decreased cell apoptosis, preserved mitochondrial membrane potential, and enhanced the blastocyst rate. These results offer valuable insights for optimizing the porcine oocyte IVM culture system.

Molecular dynamics of chemotactic signalling orchestrates dental pulp stem cell fibrosis during aging

Aging often triggers dental pulp fibrosis, resulting in clinical repercussions such as increased susceptibility to dental infections, compromised tooth vitality, and reduced responsiveness to dental interventions. Despite its prevalence, the precise molecular mechanisms underlying this condition remains unclear. Leveraging single-cell transcriptome analysis from both our own and publicly available datasets, we identified Ccrl2+ macrophages as particularly vulnerable during the early stages of aging. Notably, dental pulp progenitors with high expression of RARRES2, a unique ligand for CCRL2, facilitate the selective recruitment of a specific macrophage population to the stem cell niches. This process culminates in the formation of the ligand-receptor complex that engages CMKLR1, a receptor broadly expressed across macrophage populations. This interaction drives macrophage activation and expansion through the RARRES2/CCRL2/CMKLR1 axis. Through rigorous experimental validation, we demonstrated that macrophage activation and expansion within stem cell niches lead to increased secretion of proinflammatory factors, promoting dental pulp fibrosis during aging. Our findings uncover the intricate molecular dynamics of dental pulp aging, emphasizing immune microenvironment interactions. This study provides a novel perspective on potential therapeutic strategies for age-related pulp diseases by targeting macrophages and modulating the immune microenvironment.

Blast-Overpressure Induced Modulation of PARP-SIRT-NRF2 Axis in Stress Signaling of Astrocytes and Microglia

BACKGROUND

The pathomechanism of blast traumatic brain injury (TBI) and blunt TBI is different. In blast injury, evidence indicates that a single blast exposure can often manifest long-term neurological impairments. However, its pathomechanism is still elusive, and treatments have been symptomatic. Poly adenosine diphosphate (ADP) ribose polymerase-1 (PARP1) is implicated in the parthanatos and secondary neuroinflammation. Animal studies indicate the over-activation of PARP1 as a significant downstream event underlying the neurological sequelae of several traumatic and neurodegenerative disorders, irrespective of the mode of cell death. PARP over-activation forms ADP polymers on several nuclear proteins, known as trans-PARylation, by consuming nicotinamide adenine dinucleotide (NAD+) and ATP. As NAD+ is a substrate for sirtuins, ithas also been implicated in the oxidative stress underlying TBI pathology.

HYPOTHESIS

We recently established the implication of PARP1 following blast overpressure (BOP) and its differential response on astrocytes and microglial cells. We found that the inhibition of PARP is proven beneficial by attenuating oxidative stress. In this study, we hypothesized the involvement of the PARP1-SIRT-NRF2 axis following induced blast-induced PARP over-activation in glial cells for the manifestation of oxidative stress in BOP insults.

OBJECTIVE

The objective is to determine the downstream modulation of the PARP-SIRT-NRF2 axis and changes in ATP levels following blast exposure in astrocytes and microglia cell lines.

RESULTS

As a result of NAD+ being a common substrate for PARP1 and Sirtuins, we found the decreased expression of SIRT1, SIRT3, and NRF2, a central transcriptional regulator for the expression of antioxidant genes. We found that ATP levels were elevated post-BOP from both glycolysis and oxidative phosphorylation (OXPHOS), an increase of ATP by glycolysis more significant than OXPHOS source, indicating the proinflammation post-BOP.

CONCLUSION

This result shows that blast-induced PARP1 over-activation impacts the deacetylation activity of sirtuins and consequently impacts the regulation of antioxidant levels in astrocytes and microglia.