Caffeine Targets SIRT3 to Enhance SOD2 Activity in Mitochondria

Caffeine upregulates SIRT3 expression to ameliorate astrocytes-mediated HIV-1 Tat neurotoxicity via suppression of EGR1 signaling pathway

Caffeine is one of the most popular consumed psychostimulants that mitigates several neurodegenerative diseases. Nevertheless, the roles and molecular mechanisms of caffeine in HIV-associated neurocognitive disorders (HAND) remain largely unclear. Transactivator of transcription (Tat) is a major contributor to the neuropathogenesis of HAND in the central nervous system. In the present study, we determined that caffeine (100 µM) treatment significantly ameliorated Tat-induced decreased astrocytic viability, oxidative stress, inflammatory response and excessive glutamate and ATP release, thereby protecting neurons from apoptosis. Subsequently, SIRT3 was demonstrated to display neuroprotective effects against Tat during caffeine treatment. In addition, Tat downregulated SIRT3 expression via activation of EGR1 signaling, which was reversed by caffeine treatment in astrocytes. Overexpression of EGR1 entirely abolished the neuroprotective effects of caffeine against Tat. Furthermore, counteracting Tat or caffeine-induced differential expression of SIRT3 abrogated the neuroprotection of caffeine against Tat-triggered astrocytic dysfunction and neuronal apoptosis. Taken together, our study establishes that caffeine ameliorates astrocytes-mediated Tat neurotoxicity by targeting EGR1/SIRT3 signaling pathway. Our findings highlight the beneficial effects of caffeine on Tat-induced astrocytic dysfunction and neuronal death and propose that caffeine might be a novel therapeutic drug for relief of HAND.

Caffeine and neonatal acute kidney injury

Acute kidney injury is one of the most threatening diseases in neonates, with complex pathogenesis and limited treatment options. Caffeine is a commonly used central nervous system stimulant for treating apnea in preterm infants. There is compelling evidence that caffeine may have potential benefits for preventing neonatal acute kidney injury, but comprehensive reports are lacking in this area. Hence, this review aims to provide a summary of clinical data on the potential benefits of caffeine in improving neonatal acute kidney injury. Additionally, it delves into the molecular mechanisms underlying caffeine's effects on acute kidney injury, with a focus on various aspects such as oxidative stress, adenosine receptors, mitochondrial dysfunction, endoplasmic reticulum stress, inflammasome, autophagy, p53, and gut microbiota. The ultimate goal of this review is to provide information for healthcare professionals regarding the link between caffeine and neonatal acute kidney injury and to identify gaps in our current understanding.

Design, Synthesis, and In Vivo Evaluation of Isosteviol Derivatives as New SIRT3 Activators with Highly Potent Cardioprotective Effects

Cardiovascular diseases (CVDs) persist as the predominant cause of mortality, urging the exploration of innovative pharmaceuticals. Mitochondrial dysfunction stands as a pivotal contributor to CVDs development. Sirtuin 3 (SIRT3), a prominent mitochondrial deacetylase known for its crucial role in protecting mitochondria against damage and dysfunction, has emerged as a promising therapeutic target for CVDs treatment. Utilizing isosteviol, a natural ent-beyerene diterpenoid, 24 derivatives were synthesized and evaluated in vivo using a zebrafish model, establishing a deduced structure-activity relationship. Among these, derivative 5v exhibited significant efficacy in doxorubicin-induced cardiomyopathy in zebrafish and murine models. Subsequent investigations revealed that 5v selectively elevated SIRT3 expression, leading to the upregulation of SOD2 and OPA1 expression, effectively preventing mitochondrial dysfunction, mitigating oxidative stress, and preserving cardiomyocyte viability. As a novel structural class of SIRT3 activators with robust therapeutic effects, 5v emerges as a promising candidate for further drug development.

Parkin is a critical player in the effects of caffeine over mitochondrial quality control pathways during skeletal muscle regeneration in mice

AIM

This study aimed to investigate the effects of caffeine on pathways associated with mitochondrial quality control and mitochondrial capacity during skeletal muscle regeneration, focusing on the role of Parkin, a key protein involved in mitophagy.

METHODS

We used in vitro C2C12 myoblast during differentiation with and without caffeine in the medium, and we evaluated several markers of mitochondrial quality control pathways and myotube growth. In vivo experiments, we used C57BL/6J (WT) and Parkintm 1Shn lineage (Parkin-/- ) mice and injured tibial anterior muscle. The mice regenerated TA muscle for 3, 10, and 21 days with or without caffeine ingestion. TA muscle was used to analyze the protein content of several markers of mitochondrial quality pathways, muscle satellite cell differentiation, and protein synthesis. Furthermore, it analyzed mtDNA, mitochondrial respiration, and myofiber growth.

RESULTS

C2C12 differentiation experiments showed that caffeine decreased Parkin content, potentially leading to increased DRP1 and PGC-1α content and altered mitochondrial population, thereby enhancing growth capacity. Using Parkin-/- mice, we found that caffeine intake during the regenerative process induces an increase in AMPKα phosphorylation and PGC-1α and TFAM content, changes that were partly Parkin-dependent. In addition, the absence of Parkin potentiates the ergogenic effect of caffeine by increasing mitochondrial capacity and myotube growth. Those effects are related to increased ATF4 content and activation of protein synthesis pathways, such as increased 4E-BP1 phosphorylation.

CONCLUSION

These findings demonstrate that caffeine ingestion changes mitochondrial quality control during skeletal muscle regeneration, and Parkin is a central player in those mechanisms.

SIRT3 Activation a Promise in Drug Development? New Insights into SIRT3 Biology and Its Implications on the Drug Discovery Process

Sirtuins catalyze deacetylation of lysine residues with a NAD+-dependent mechanism. In mammals, the sirtuin family is composed of seven members, divided into four subclasses that differ in substrate specificity, subcellular localization, regulation, as well as interactions with other proteins, both within and outside the epigenetic field. Recently, much interest has been growing in SIRT3, which is mainly involved in regulating mitochondrial metabolism. Moreover, SIRT3 seems to be protective in diseases such as age-related, neurodegenerative, liver, kidney, heart, and metabolic ones, as well as in cancer. In most cases, activating SIRT3 could be a promising strategy to tackle these health problems. Here, we summarize the main biological functions, substrates, and interactors of SIRT3, as well as several molecules reported in the literature that are able to modulate SIRT3 activity. Among the activators, some derive from natural products, others from library screening, and others from the classical medicinal chemistry approach.

Sirtuin 3-mediated deacetylation of superoxide dismutase 2 ameliorates sodium fluoride-induced mitochondrial dysfunction in porcine oocytes

Fluoride exerts detrimental effects on germ cells and increases the infertility rate in women. Nevertheless, the precise mechanisms behind the developmental abnormalities caused by fluoride in oocytes remain poorly comprehended. The current study, we established mitochondrial damage model in oocytes via 50 μg/mL sodium fluoride (NaF) supplementation. We then examined the effects of honokiol in preventing mitochondrial deficits caused by NaF and investigated the mechanisms through which honokiol protects oocytes. The findings investigated that NaF increased levels of mitochondrial reactive oxygen species (mtROS) and hindered mitochondrial function, as evidenced by the dissipation of mitochondrial membrane potential, abnormal expression of mitochondrial DNA copy numbers, and mtDNA harm in oocytes. mtROS scavenging using Mito-TEMPO alleviated oxidative damage in mitochondria and restored the oocyte developmental competence. Superoxide dismutase 2 (SOD2) acetylation was significantly increased, whereas sirtuin 3 (SIRT3) expression was decreased in NaF-treated oocytes. The addition of honokiol helped in the deacetylation of SOD2 at K122 through SIRT3, resulting in the removal of excessive mtROS and the recovery of mitochondrial function. Therefore, SIRT3/SOD2 pathway aids honokiol in mitigating fluoride-induced mitochondrial dysfunction. Overall, honokiol improved the mitochondrial harm caused by NaF by controlling mtROS and mitochondrial function, with the SIRT3/SOD2 pathway having an important function. These findings suggest honokiol as a potential therapeutic strategy for NaF-induced oocyte development and mitochondrial deficits.

Quantification of skin penetration of caffeine and propylene glycol applied topically in a mixture by tailored multivariate curve resolution-alternating least squares of depth-resolved Raman spectra

The quantitative determination of topically applied substances in the skin is severely limited and represents a challenging task. The porcine skin ex vivo was topically treated with a gel containing caffeine (CF) and propylene glycol (PG), and depth-resolved Raman spectra were recorded with two confocal Raman microscopes. We applied a novel tailored multivariate curve resolution-alternating least squares method to the selected spectral regions (512-604 and 778-1148 cm-1 ) of gel-treated skin and quantitatively determined the concentrations of CF and PG in the stratum corneum (SC). The highest concentration of CF (181 mg/cm3 ) was found at the surface, while PG (384 mg/cm3 ) was found at 10% SC depth, indicating the formation of a reservoir at the superficial SC. The concentrations of CF and PG decreased monotonically and reached the detection limit at ≈60% and ≈80% SC depth, respectively, indicating that neither permeate the SC.

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy

INTRODUCTION

Spinal cord injury (SCI) is a central nervous system injury that is primarily traumatic and manifests as motor, sensory, and autonomic dysfunction below the level of damage. Our previous studies confirmed the ability of zinc to protect mitochondria, protect neurons and promote spinal cord recovery. However, the role of zinc in Parthanatos is unknown.

AIM

We investigated the effects of zinc in Parthanatos from oxidative stress and mitophagy. We elucidated the role of SIRT3 in providing new ideas for treating spinal cord injury.

THE RESULTS

Zinc protected SCI mice by regulating Parthanatos. On the one hand, zinc eliminated ROS directly through SIRT3 deacetylation targeting SOD2 to alleviate Parthanatos. On the other hand, zinc eliminated ROS indirectly through SIRT3-mediated promotion of mitophagy to alleviate Parthanatos.

CONCLUSION

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy.

Sex and age differences in AMPK phosphorylation, mitochondrial homeostasis, and inflammation in hearts from inflammatory cardiomyopathy patients

Linked to exacerbated inflammation, myocarditis is a cardiovascular disease, which may lead to dilated cardiomyopathy. Although sex and age differences in the development of chronic myocarditis have been postulated, underlying cellular mechanisms remain poorly understood. In the current study, we aimed to investigate sex and age differences in mitochondrial homeostasis, inflammation, and cellular senescence. Cardiac tissue samples from younger and older patients with inflammatory dilated cardiomyopathy (DCMI) were used. The expression of Sirt1, phosphorylated AMPK, PGC-1α, Sirt3, acetylated SOD2, catalase, and several mitochondrial genes was analyzed to assess mitochondrial homeostasis. The expression of NF-κB, TLR4, and interleukins was used to examine the inflammatory state in the heart. Finally, several senescence markers and telomere length were investigated. Cardiac AMPK expression and phosphorylation were significantly elevated in male DCMI patients, whereas Sirt1 expression remained unchanged in all groups investigated. AMPK upregulation was accompanied by a preserved expression of all mitochondrial proteins/genes investigated in older male DCMI patients, whereas the expression of TOM40, TIM23, and the mitochondrial oxidative phosphorylation genes was significantly reduced in older female patients. Mitochondrial homeostasis in older male patients was further supported by the reduced acetylation of mitochondrial proteins as indicated by acetylated SOD2. The inflammatory markers NF-κB and TLR4 were downregulated in older male DCMI patients, whereas the expression of IL-18 was increased in older female patients. This was accompanied by progressed senescence in older DCMI hearts. In conclusion, older women experience more dramatic immunometabolic disorders on the cellular level than older men.

Oroxylin A relieves intrauterine adhesion in mice through inhibiting macrophage pyroptosis via SIRT3-SOD2-ROS pathway

Intrauterine adhesion (IUA) is manifested by endometrial fibrosis and inflammation, which seriously affects female reproductive health. Macrophages are mainly inflammatory cells and have been reported to participate in the fibrosis of IUA. Oroxylin A (OA), a kind of flavonoid compounds, was showed to possess the inhibitory effects on inflammation and fibrosis. However, the role of OA in IUA remains unclear. In the present study, we found that OA effectively alleviated the level of inflammation and uterine fibrosis in IUA mice. OA also decreased the macrophage pyroptosis which increased in uteri of IUA mice. Pyroptosis is a programmed cell death accompanied by an inflammatory response. Moreover, OA repressed the mediators of pyroptosis including the expression of NOD-like receptor family pyrin domain containing 3 (NLRP3), caspase-1 and Gasdermin D (GSDMD) and the release of IL-1β, IL-18 and cleaved-caspase-1 in J774A.1 cells induced by LPS/ATP in vitro. Mechanistically, the alleviation of OA on uterine fibrosis is achieved by inhibiting macrophage pyroptosis via SIRT3-SOD2-ROS pathway. Our data indicate that OA may serve as an effective agent for the treatment of the endometrial fibrosis with IUA.

The role of sirtuins in dermal fibroblast function

The sirtuins are a family of seven proteins that perform a variety of dermatological functions and help maintain both the structure and function of the skin. More specifically, the sirtuins have been shown to be altered in multiple dermal cell types including dermal fibroblasts. The functions of dermal fibroblasts are extensive, and include playing a significant role in wound healing as well as helping to maintain the integrity of the skin. As dermal fibroblasts age, they can undergo a state of permanent cell cycle arrest, known as cellular senescence. This senescent process can occur as a result of various stressors, including oxidative stress, ultraviolet radiation -induced stress, and replicative stress. In recent years, there has been a growing interest in both enhancing the cutaneous fibroblast’s ability to facilitate wound healing and altering fibroblast cellular senescence. Thus, in this review, we examine the relationship between sirtuin signaling and dermal fibroblasts to understand how this family of proteins may modulate skin conditions ranging from the wound healing process to photocarcinogenesis associated with fibroblast senescence. Additionally, we offer supporting data from experiments examining the relationship between fibroblast senescence and sirtuin levels in an oxidative stress model indicating that senescent dermal fibroblasts exhibit diminished sirtuin levels. Furthermore, we survey the research on the role of sirtuins in specific dermatological disease states that where dermal fibroblast function has been implicated. Finally, we conclude with outlining potential clinical applications of sirtuins in dermatology. In sum, we find that the literature on the involvement of sirtuins in dermal fibroblasts is limited, with research still in its early stages. Nevertheless, intriguing preliminary findings merit additional investigation into the clinical implications of sirtuins in dermatology.

The Effect of N6-Methyladenosine Regulators and m6A Reader YTHDC1-Mediated N6-Methyladenosine Modification Is Involved in Oxidative Stress in Human Aortic Dissection

Aortic dissection (AD) develops pathological changes in the separation of the true and false aortic lumen, with high lethality. m6A methylation and oxidative stress have also been shown to be involved in the onset of AD. Through bioinformatics methods, three differentially expressed m6A regulators (YTHDC1, YTHDC2, and RBM15) were excavated from the GSE52093 dataset in the Gene Expression Omnibus (GEO) database, and functional enrichment analysis of the differentially expressed genes (DEGs) regulated by m6A regulators was performed. Then, the genes with oxidative stress-related functions among these genes were found. The protein interaction network of the oxidative stress-related genes and the competing endogenous RNA- (ceRNA-) miRNA-mRNA network were constructed. Among them, DHCR24, P4HB, and PDGFRA, which have m6A differences in AD samples, were selected as key genes. We also performed immune infiltration analysis, as well as cell-gene correlation analysis, on samples from the dataset. The results showed that YTHDC1 was positively correlated with macrophage M1 and negatively correlated with macrophage M2. Finally, we extracted AD and healthy aorta RNA and protein from human tissues that were taken from AD patients and patients who received heart transplants, performed quantitative real-time PCR (qRT-PCR) on YTHDC2 and RBM15, and performed qRT-PCR and western blot (WB) detection on YTHDC1 to verify their differences in AD. The mRNA and protein levels of YTHDC1 were consistent with the results of bioinformatics analysis and were downregulated in AD. Immunofluorescence (IF) was used to colocalize YTHDC1 and endothelial cell marker CD31. After knocking down YTHDC1 in human umbilical vein endothelial cells (HUVECs), reactive oxygen species (ROS) levels had a tendency to increase and the expression of peroxide dismutase SOD2 was decreased. This study provides assistance in discovering the role of m6A regulator YTHDC1 in AD. In particular, m6A modification participates in oxidative stress and jointly affects AD.

The Role of Sirtuins in Sarcopenia and Frailty

The population of older individuals is increasing rapidly, but only a small fraction among them is able to experiences a healthy life. Due to lack of physical exercise and oxidative stress, aging leads to sarcopenia and finally end up with frailty. Sarcopenia is a component of the frailty and described as age related degenerative changes in the skeletal muscle mass, strength and quality. Though the loss of muscle strength and mass gradually seem inevitable during aging, it can be partially prevented or overcome by a deeper insight into the pathogenesis. Sirtuin protein leads to longevity across different organisms ranging from worms to mammals. Expression of sirtuin protein increases during physical exercise and thus strengthens muscle mass. Satellite cells leads to muscle repair in a SIRT1 dependent manner. In addition, SIRT1 improves insulin sensitivity and induces autophagy in the aged mice. The current paper discussed the putative role of sirtuins in sarcopenia and frailty. Moreover, it highlighted the pathways by which sirtuins can inhibit ROS production, inflammation and mitochondrial dysfunctions and therefore confers a protective role against frailty and sarcopenia. The critical role of sirtuins in the sarcopenia and frailty pathogenesis can eventually fuel the development of novel interventions by targeting sirtuins.

Caffeine and Its Antioxidant Properties-It Is All about Dose and Source

Caffeine is the most frequently used substance with a central nervous system stimulant effect, but its consumption is most often due to the intake of foods and drinks that contain it (coffee, tea, chocolate, food supplements with plant extracts of Guarana, Mate herba, Cola nuts). Due to its innocuity, caffeine is a safe xanthine alkaloid for human consumption in a wide range of doses, being used for its central nervous stimulating effect, lipolytic and diuresis-enhancing properties, but also as a permitted ergogenic compound in athletes. In addition to the mechanisms that explain the effects of caffeine on the targeted organ, there are many proposed mechanisms by which this substance would have antioxidant effects. As such, its consumption prevents the occurrence/progression of certain neurodegenerative diseases as well as other medical conditions associated with increased levels of reactive oxygen or nitrogen species. However, most studies that have assessed the beneficial effects of caffeine have used pure caffeine. The question, therefore, arises whether the daily intake of caffeine from food or drink has similar benefits, considering that in foods or drinks with a high caffeine content, there are other substances that could interfere with this action, either by potentiating or decreasing its antioxidant capacity. Natural sources of caffeine often combine plant polyphenols (phenol-carboxylic acids, catechins) with known antioxidant effects; however, stimulant drinks and dietary supplements often contain sugars or artificial sweeteners that can significantly reduce the effects of caffeine on oxidative stress. The objective of this review is to clarify the effects of caffeine in modulating oxidative stress and assess these benefits, considering the source and the dose administered.

Trehalose Attenuates Oxidative Stress and Endoplasmic Reticulum Stress-Mediated Apoptosis in IPEC-J2 Cells Subjected to Heat Stress

This study was carried out to investigate the effects of trehalose (Tre) on antioxidant capacity, endoplasmic reticulum stress (ERS) response and apoptosis of heat-stressed intestinal porcine epithelial cells (IPEC-J2). IPEC-J2 cells were cultured at 37 °C until the end of the experiment (control, CON); exposed to heat stress for 2 h (43 °C, HS); or pretreated with 0.1, 1, 5, 10, and 15 mM trehalose at 37 °C for 4 h prior to heat stress exposure for 2 h. The optimum level of trehalose for protecting against HS-induced cell injuries was determined to be 10 mM, as evidenced by the highest cellular viability and lowest malondialdehyde (MDA) content and lactate dehydrogenase (LDH) activity. Based on these, IPEC-J2 cells were divided into three groups: the first group was cultured at 37 °C until the end of the experiment (control, CON); the second group was exposed to heat stress for 2 h (43 °C, HS); the third group was pretreated with 10 mM trehalose for 4 h at 37 °C prior to heat stress exposure for 2 h (Tre + HS). The reactive oxygen species (ROS) content, superoxide dismutase (SOD) activity, mitochondrial membrane potential (MMP) changes, and expressions of the manganese superoxide dismutase (SOD2), ERS and apoptosis-related proteins were determined. Compared to the CON group, HS significantly increased ROS generation (p < 0.01), decreased SOD activity (p < 0.05), and downregulated protein expression of SOD2 (p < 0.01). Compared to the HS group, Tre supplementation reduced ROS levels and increased SOD activity and SOD2 expression to the levels that were comparable to the control (p < 0.05). The HS-induced ERS response was evidenced by the increased protein expressions of glucose-regulated protein 78 (GRP78) (p < 0.01), eukaryotic translation initiation factor 2α (p-eif2α) (p < 0.01), transcription activator 4 (ATF4) (p < 0.01), and the protein expression of C/EBP homologous protein (CHOP) (p < 0.01), which were the four hallmarks of ERS. The Tre + HS group showed lower expressions of GRP78 (p < 0.01), p-eif2α (p < 0.01), ATF4 (p < 0.01), and CHOP (p < 0.01) than that of the HS group. Tre pretreatment attenuated HS-induced mitochondrial apoptosis in IPEC-J2 cells, demonstrated by the increased MMP and decreased proapoptotic proteins active caspase 3, Bax, and cytochrome c (Cyt c). Taken together, trehalose can protect against HS-induced oxidative damage and endoplasmic reticulum stress-mediated apoptosis in IPEC-J2 cells. These data may provide a nutritional strategy for alleviating heat stress in pig production.

The interplay of epilepsy with impaired mitophagy and autophagy linked dementia (MAD): A review of therapeutic approaches

The duration and, age of dementia have been linked to a higher risk of seizures. The exact mechanism that drives epileptogenesis in impaired mitophagy and autophagy linked dementia (MAD) is fully defined after reviewing the Scopus, Publon, and Pubmed databases. The epileptogenesis in patients with Alzheimer's disease dementia (ADD) and Parkinson's disease dementia (PDD) is due to involvement of amyloid plaques (Aβ), phosphorylated tau (pTau), Parkin, NF-kB and NLRP3 inflammasome. Microglia, the prime protective and inflammatory cells in the brain exert crosstalk between mitophagy and inflammation. Several researchers believed that the inflammatory brain cells microglia could be a therapeutic target for the treatment of a MAD associated epilepsy. There are conventional antiepileptic drugs such as gabapentin, lamotrigine, phenytoin sodium, carbamazepine, oxcarbazepine, felbamate, lamotrigine, valproate sodium, and topiramate are prescribed by a psychiatrist to suppress seizure frequency. Also, the conventional drugs generate serious adverse effects and synergises dementia characteristics. The adverse effect of carbamazepine is neurotoxic and also, damages haemopoietic system and respiratory tract. The phenytoin treatment causes cerebellar defect and anemia. Dementia and epilepsy have a complicated relationship, thus targeting mitophagy for cure of epileptic dementia makes sense. Complementary and alternative medicine (CAM) is one of the rising strategies by many patients of the world, not only to suppress seizure frequency but also to mitigate dementia characteristics of patients. Therefore our present review focus on the interplay between epilepsy and MAD and their treatment with CAM approaches.

Role of mitochondria on UV-induced skin damage and molecular mechanisms of active chemical compounds targeting mitochondria

Mitochondria are the principal place of energy metabolism and ROS production, leading to mtDNA being especially sensitive to the impacts of oxidative stress. Our review aims to elucidate and update the mechanisms of mitochondria in UV-induced skin damage. The mitochondrial deteriorative response to UV manifests morphological and functional alterations, including mitochondrial fusion and fission, mitochondrial biogenesis, mitochondrial energy metabolism and mitophagy. Additionally, we conclude the effect and molecular mechanisms of active chemical components to protect skin from UV-induced damage via mitochondrial protection which have been described in the last five years, showing prospective prospects in cosmetics as new therapeutic targets.

Interleukin-13 promotes cellular senescence through inducing mitochondrial dysfunction in IgG4-related sialadenitis

Immunoglobulin G4-related sialadenitis (IgG4-RS) is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood. The aim of this study was to explore the role and mechanism of interleukin-13 (IL-13) in the cellular senescence during the progress of IgG4-RS. We found that the expression of IL-13 and IL-13 receptor α1 (IL-13Rα1) as well as the number of senescent cells were significantly higher in the submandibular glands (SMGs) of IgG4-RS patients. IL-13 directly induced senescence as shown by the elevated activity of senescence-associated β-galactosidase (SA-β-gal), the decreased cell proliferation, and the upregulation of senescence markers (p53 and p16) and senescence-associated secretory phenotype (SASP) factors (IL-1β and IL-6) in SMG-C6 cells. Mechanistically, IL-13 increased the level of phosphorylated signal transducer and activator of transcription 6 (p-STAT6) and mitochondrial-reactive oxygen species (mtROS), while decreased the mitochondrial membrane potential, ATP level, and the expression and activity of superoxide dismutase 2 (SOD2). Notably, the IL-13-induced cellular senescence and mitochondrial dysfunction could be inhibited by pretreatment with either STAT6 inhibitor AS1517499 or mitochondria-targeted ROS scavenger MitoTEMPO. Moreover, IL-13 increased the interaction between p-STAT6 and cAMP-response element binding protein (CREB)-binding protein (CBP) and decreased the transcriptional activity of CREB on SOD2. Taken together, our findings revealed a critical role of IL-13 in the induction of salivary gland epithelial cell senescence through the elevated mitochondrial oxidative stress in a STAT6–CREB–SOD2-dependent pathway in IgG4-RS.

Effects of Coffee on Sirtuin-1, Homocysteine, and Cholesterol of Healthy Adults: Does the Coffee Powder Matter?

Background: Coffee is one of the most popular beverages globally and contains several bioactive compounds that are relevant to human health. Many nutritional strategies modulate sirtuin-1, thereby impacting aging and cardiometabolic health. This study investigated the influence of different blended coffees on serum sirtuin-1, blood lipids, and plasma homocysteine. Methods: An eight-week randomized clinical trial that included 53 healthy adults of both sexes analyzed the effects of daily intake of 450 to 600 mL of pure Arabica or blended (Arabica + Robusta) coffee intake of filtered coffee on blood sirtuin-1, lipids, and homocysteine. Results: Both Arabica and blended coffees similarly increased serum sirtuin-1 concentration, from 0.51 to 0.58 ng/mL (p = 0.004) and from 0.40 to 0.49 ng/mL (p = 0.003), respectively, without changing plasma homocysteine, folic acid, glucose, and CRP. However, the blended coffee intake increased total cholesterol from 4.70 to 5.17 mmol/L (p < 0.001) and LDL-cholesterol from 2.98 to 3.32 mmol/L (p < 0.001), as well as HDL-c from 1.26 to 1.36 mmol/L (p < 0.001). Conclusion: Both coffee powders increased sirtuin-1 expression, but our results suggest that blended coffee had hypercholesterolemic effects which could increase cardiovascular risk. Therefore, preference should be given to Arabica coffee for the best cardiometabolic benefits of coffee.

Emerging roles of Sirtuins in alleviating alcoholic liver Disease: A comprehensive review

Sirtuins (SIRTs), a NAD⁺ family of dependent deacetylases, are involved in the regulation of various human diseases. Recently, accumulating evidence has uncovered number of substrates and crucial roles of SIRTs in the pathogenesis of alcoholic liver disease (ALD). However, systematic reports are still lacking, so this review provides a comprehensive profile of the crucial physiological functions of SIRTs and its role in attenuating ALD, including alcoholic liver steatosis, steatohepatitis, and fibrosis. SIRTs play beneficial roles in energy/lipid metabolism, oxidative stress, inflammatory response, mitochondrial homeostasis, autophagy and necroptosis of ALD via regulating multiple signaling transduction pathways such as AMPK, LKB1, SREBP1, Lipin1, PGC-1α, PPARα/γ, FoxO1/3a, Nrf2/p62, mTOR, TFEB, RIPK1/3, HMGB1, NFATc4, NF-κB, TLR4, NLRP3, P2X7R, MAPK, TGF1β/Smads and Wnt/β-catenin. In addition, the mechanism and clinical application of natural/ synthetic SIRTs agonists in ALD are summarized, which provide a new idea for the treatment of ALD and basic foundation for further studies into target drugs.

The Protective Effects of Mogroside V Against Neuronal Damages by Attenuating Mitochondrial Dysfunction via Upregulating Sirtuin3

Mitochondrial dysfunction and oxidative stress are thought to play a dominant role in the pathogenesis of Parkinson's disease (PD). Mogroside V (MV), extracted from Siraitia grosvenorii, exhibits antioxidant-like activities. The aim of this study was to investigate the function of MV in neuroprotection in PD and to reveal its mechanism of action. To that end, we firstly set up mice models of PD with unilateral striatum injection of 0.25 mg/kg rotenone (Rot) and co-treated with 2.5 mg/kg, 5 mg/kg, and 10 mg/kg MV by gavage. Results showed that Rot-induced motor impairments and dopaminergic neuronal damage were reversed by treatment of 10 mg/kg MV. Then, we established cellular models of PD using Rot-treated SH-SY5Y cells, which were divided into six groups, including control, Rot, and co-enzyme Q10 (CQ10), as well as MV groups, MV25, MV50, and MV100 treated with 25 μM, 50 μM, and 100 μM MV doses, respectively. Results demonstrated that MV effectively attenuates Rot neurotoxicity through a ROS-related intrinsic mitochondrial pathway. MV reduced overproduction of reactive oxygen species (ROS), recovered the mitochondrial membrane potential (MMP), and increased the oxygen consumption rate and adenosine triphosphate (ATP) production in a dose-dependent manner. Hence, treatment with MV led to a reduction in the number of apoptotic cells, as reflected by Annexin-V/propidium iodide co-staining using flow cytometry and TdT-mediated dUTP Nick-End Labeling (TUNEL) assay. In addition, the Sirtuin3 (SIRT3) protein level and activity were decreased upon exposure to Rot both in substantia nigra (SN) of mice and SH-SY5Y cells. SIRT3 impairment hyperacetylated a key mitochondrial antioxidant enzyme, superoxide dismutase 2 (SOD2). MV alleviates SIRT3 and SOD2 molecular changes. However, after successfully inhibiting SIRT3 by its specific inhibitor 3-1H-1, 2, 3-triazol-4-yl pyridine (3TYP), MV was not able to reduce ROS levels, reverse abnormal MMP, or decrease apoptotic cells. Motor impairments and dopaminergic neuronal injury in the SN were alleviated with the oral administration of MV in Rot-treated PD mice, indicating a relationship between protection against defective motility and preservation of dopaminergic neurons. Therefore, we conclude that MV can alleviate Rot-induced neurotoxicity in a PD model, and that SIRT3 may be an important regulator in the protection of MV.

Cardiovascular Inflammaging: Mechanisms and Translational Aspects

Aging is one of the major non-reversible risk factors for several chronic diseases, including cancer, type 2 diabetes, dementia, and cardiovascular diseases (CVD), and it is a key cause of multimorbidity, disability, and frailty (decreased physical activity, fatigue, and weight loss). The underlying cellular mechanisms are complex and consist of multifactorial processes, such as telomere shortening, chronic low-grade inflammation, oxidative stress, mitochondrial dysfunction, accumulation of senescent cells, and reduced autophagy. In this review, we focused on the molecular mechanisms and translational aspects of cardiovascular aging-related inflammation, i.e., inflammaging.

The bibenzyl derivatives of Dendrobium officinale prevent UV-B irradiation induced photoaging via SIRT3

Dendrobium officinale is a valuable medicinal herb that is widely used in traditional Chinese medicine. The chemical constituents of D. officinale have attracted much attention and a large number of compounds have been reported including many bibenzyl derivatives. 13 bibenzyl derivatives from D. officinale were sent for molecular docking, surface plasmon resonance (SPR) assay and after detection of Mn-SOD and SIRT3 activities in or not in HaCaT cells, it was concluded that bibenzyl derivatives did not directly activate Mn-SOD but promoted SIRT3 proteins. In addition, HaCaT cells were irradiated with UV-B to induce an oxidative stress model in vitro to further verify the effect of bibenzyl derivatives. The results show that bibenzyl derivatives could directly bind to SIRT3, enhance the deacetylation and then activate Mn-SOD, so as to protect UV-B induced skin photoaging.

Bitter taste receptors protect against skin aging by inhibiting cellular senescence and enhancing wound healing

BACKGROUND/OBJECTIVES

Bitter taste receptors are taste signaling pathway mediators, and are also expressed and function in extra-gustatory organs. Skin aging affects the quality of life and may lead to medical issues. The purpose of this study was to better understand the anti-skin aging effects of bitter taste receptors in D-galactose (D-gal)-induced aged human keratinocytes, HaCaT cells.

MATERIALS/METHODS

Expressions of bitter taste receptors in HaCaT cells and mouse skin tissues were examined by polymerase chain reaction assay. Bitter taste receptor was overexpressed in HaCaT cells, and D-gal was treated to induce aging. We examined the effects of bitter taste receptors on aging by using β-galactosidase assay, wound healing assay, and Western blot assay.

RESULTS

TAS2R16 and TAS2R10 were expressed in HaCaT cells and were upregulated by D-gal treatment. TAS2R16 exerted protective effects against skin aging by regulating p53 and p21, antioxidant enzymes, the SIRT1/mechanistic target of rapamycin pathway, cell migration, and epithelial-mesenchymal transition markers. TAS2R10 was further examined to confirm a role of TAS2R16 in cellular senescence and wound healing in D-gal-induced aged HaCaT cells.

CONCLUSIONS

Our results suggest a novel potential preventive role of these receptors on skin aging by regulating cellular senescence and wound healing in human keratinocyte, HaCaT.

Putative Candidate Drug Targets for Sarcopenia-Related Traits Identified Through Mendelian Randomization Analysis of the Blood Proteome

Purpose: The increasing prevalence of sarcopenia remains an ongoing challenge to health care systems worldwide. The lack of treatments encouraged the discovery of human proteomes to find potential therapeutic targets. As one of the major components of the human proteome, plasma proteins are functionally connected with various organs of the body to regulate biological processes and mediate overall homeostasis, which makes it crucial in various complex processes such as aging and chronic diseases. By performing a systematic causal analysis of the plasma proteome, we attempt to reveal the etiological mechanism and discover drug targets for sarcopenia. Methods: By using data from four genome-wide association studies for blood proteins and the UK Biobank data for sarcopenia-related traits, we applied two-sample Mendelian randomization (MR) analysis to evaluate 310 plasma proteins as possible causal mediators of sarcopenia-related traits: appendicular lean mass (ALM) and handgrip strength (right and left). Then we performed a two-sample bidirectional Mendelian randomization analysis for the identified putatively causal proteins to assess potential reverse causality that the trait values may influence protein levels. Finally, we performed phenome-wide MR analysis of the identified putatively causal proteins for 784 diseases to test the possible side effects of these proteins on other diseases. Results: Five plasma proteins were identified as putatively causal mediators of sarcopenia-related traits. Specifically, leukocyte immunoglobulin-like receptor subfamily B member 2 (LILRB2), asporin (ASPN), and contactin-2 (CNTN2) had potential causal effects on appendicular lean mass, and ecto-ADP-ribosyltransferase 4 (ART4) and superoxide dismutase 2 (SOD2) had putative causal effects on the handgrip strength, respectively. None of the five putatively causal proteins had a reverse causality relationship with sarcopenia-related traits, and no side effects on other diseases were identified. Conclusion: We identified five plasma proteins that may serve as putatively potential novel drug targets for sarcopenia. Our study attested to the value of two-sample MR analysis in identifying and prioritizing putatively potential therapeutic targets for complex diseases.

Caffeine consumption and schizophrenia: A highlight on adenosine receptor-independent mechanisms

Schizophrenia is a common psychiatric disorder which affects approximately 1% of the population worldwide. However, the complexity of etiology, treatment resistance and side effects induced by current antipsychotics, relapse prevention, and psychosocial rehabilitation are still to be uncovered. Caffeine, as the world's most widely consumed psychoactive drug, plays a crucial role in daily life. Plenty of preclinical and clinical evidence has illustrated that caffeine consumption could have a beneficial effect on schizophrenia. In this review, we firstly summarize the factors associated with the caffeine-induced beneficial effect. Then, a variety of mechanism of actions independent of adenosine receptor signaling will be discussed with an emphasis on the potential contribution of the microbiome-gut-brain axis to provide more possibilities for future therapeutic, prognosis, and social rehabilitation strategy.

Structure-Guided Design of a Small-Molecule Activator of Sirtuin-3 that Modulates Autophagy in Triple Negative Breast Cancer

Sirtuin-3 (SIRT3) is an NAD⁺-dependent protein deacetylase localized primarily in the mitochondria with many links to different types of human cancers. Autophagy, which is a highly conserved lysosomal degradation process in eukaryotic cells, has been recently reported to be positively regulated by SIRT3 in cancer; therefore, activating SIRT3-modulated autophagy may be a promising strategy for drug discovery. In this study, we discovered a small-molecule activator of SIRT3 compound 33c (ADTL-SA1215) with specific SIRT3 deacetylase activity by structure-guided design and high-throughput screening. Subsequently, compound 33c inhibited the proliferation and migration of human breast carcinoma MDA-MB-231 cells by SIRT3-driven autophagy/mitophagy signaling pathways in vitro and in vivo. Collectively, these results demonstrate that pharmacological activation of SIRT3 is a potential therapeutic approach of triple negative breast cancer (TNBC). More importantly, compound 33c may be a first-in-class specific small-molecule activator of SIRT3 that would be utilized for future cancer drug development.

Caffeine as a Factor Influencing the Functioning of the Human Body-Friend or Foe?

Nowadays, caffeine is one of the most commonly consumed substances, which presents in many plants and products. It has both positive and negative effects on the human body, and its activity concerns a variety of systems including the central nervous system, immune system, digestive system, respiratory system, urinary tract, etc. These effects are dependent on quantity, the type of product in which caffeine is contained, and also on the individual differences among people (sex, age, diet etc.). The main aim of this review was to collect, present, and analyze the available information including the latest discoveries on the impact of caffeine on human health and the functioning of human body systems, taking into account the role of caffeine in individual disease entities. We present both the positive and negative sides of caffeine consumption and the healing properties of this purine alkaloid in diseases such as asthma, Parkinson's disease, and others, not forgetting about the negative effects of excess caffeine (e.g., in people with hypertension, children, adolescents, and the elderly). In summary, we can conclude, however, that caffeine has a multi-directional influence on various organs of the human body, and because of its anti-oxidative properties, it was, and still is, an interesting topic for research studies including those aimed at developing new therapeutic strategies.

Mitochondrial proteins in heart failure: The role of deacetylation by SIRT3

Heart failure (HF) is still the leading cause of death worldwide, occurring with a variety of complex mechanisms. However, most intervention for HF do not directly target the pathological mechanisms underlying cell damage in failing cardiomyocytes. Mitochondria are involved in many physiological processes, which is an important guarantee for normal heart function. Mitochondrial dysfunction is considered to be the critical node of the development of HF. Strict modulation of the mitochondrial function can ameliorate the myocardial injury and protect cardiac function. Acetylation plays an important role in mitochondrial protein homeostasis, and SIRT3, the most important deacetylation protein in mitochondria, is involved in the maintenance of mitochondrial function. SIRT3 can delay the progression of HF by improving mitochondrial function. Herein we summarize the interaction between SIRT3 and proteins related to mitochondrial function including oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO), mitochondrial biosynthesis, mitochondrial quality control. In addition, we also sum up the effects of this interaction on HF and the research progress of treatments targeting SIRT3, so as to find potential HF therapeutic for clinical use in the future.

SIRT3-mediated mitochondrial unfolded protein response weakens breast cancer sensitivity to cisplatin

BACKGROUND

Mitochondrial unfolded protein response plays an important role in the occurrence and development of breast cancer. However, the role of mitochondrial unfolded protein response (UPR^mt) in the sensitivity of breast cancer to cisplatin chemotherapy has not yet been cleared.

OBJECTIVES

The purpose of this study is to explore the role of mitochondrial unfolded protein response in breast cancer sensitivity to cisplatin.

METHODS

In this study, qRT-PCR, Western blotting, Immunofluorescence, CCK-8, Colony formation, Transwell assay and TUNEL staining assay were used to confirm the role of UPR^mt in breast cancer cells treated with cisplatin.

RESULTS

Cisplatin increased the levels of UPR^mt including CLPP, HSP60, LONP1 in MCF7 and MDA-MB-231 cells. UPR^mt inducer Nicotinamide ribose (NR) could promote the proliferation and invasion of breast cancer cells treated with cisplatin. Importantly, SIRT3 was discovered to increase UPR^mt in breast cancer cells and silencing of SIRT3 could inhibit the effect of NR in breast cancer.

CONCLUSIONS

UPR^mt regulated by SIRT3 could protect breast cancer cell from cisplatin. Controlling SIRT3-induced UPR may be a potential therapeutic target to increase the sensitivity of breast cancer chemotherapy.

Dexmedetomidine Ameliorates Hippocampus Injury and Cognitive Dysfunction Induced by Hepatic Ischemia/Reperfusion by Activating SIRT3-Mediated Mitophagy and Inhibiting Activation of the NLRP3 Inflammasome in Young Rats

Hepatic ischemia-reperfusion (HIR) has been proven to trigger oxidative stress and pyroptosis in the hippocampus. Sirtuin 3 (SIRT3) is an essential mitochondrial protein deacetylase regulating oxidative stress and mitophagy. Dexmedetomidine (Dex) has been demonstrated to confer neuroprotection in different brain injury models. However, whether the protective effects of Dex following HIR are orchestrated by activation of SIRT3-mediated mitophagy and inhibition of NOD-like receptor protein 3 (NLRP3) inflammasome activation remains unknown. Herein, two-week-old rats were treated with Dex or a selective SIRT3 inhibitor (3-TYP)/autophagy inhibitor (3-MA) and then subjected to HIR. The results revealed that Dex treatment effectively attenuated neuroinflammation and cognitive deficits via upregulating SIRT3 expression and activity. Furthermore, Dex treatment inhibited the activation of NLRP3 inflammasome, while 3-TYP and 3-MA eliminated the protective effects of Dex, suggesting that SIRT3-mediated mitophagy executes the protective effects of Dex. Moreover, 3-TYP treatment downregulated the expression level of SIRT3 downstream proteins: forkhead-box-protein 3α (FOXO3α), superoxide dismutase 2 (SOD2), peroxiredoxin 3 (PRDX3), and cyclophilin D (CYP-D), which were barely influenced by 3-MA treatment. Notably, both 3-TYP and 3-MA were able to offset the antioxidative and antiapoptosis effects of Dex, indicating that SIRT3-mediated mitophagy may be the last step and the major pathway executing the neuroprotective effects of Dex. In conclusion, Dex inhibits HIR-induced NLRP3 inflammasome activation mainly by triggering SIRT3-mediated mitophagy.