Mitohormesis and metabolic health: The interplay between ROS, cAMP and sirtuins

Redox signaling at the crossroads of human health and disease

Redox biology is at the core of life sciences, accompanied by the close correlation of redox processes with biological activities. Redox homeostasis is a prerequisite for human health, in which the physiological levels of nonradical reactive oxygen species (ROS) function as the primary second messengers to modulate physiological redox signaling by orchestrating multiple redox sensors. However, excessive ROS accumulation, termed oxidative stress (OS), leads to biomolecule damage and subsequent occurrence of various diseases such as type 2 diabetes, atherosclerosis, and cancer. Herein, starting with the evolution of redox biology, we reveal the roles of ROS as multifaceted physiological modulators to mediate redox signaling and sustain redox homeostasis. In addition, we also emphasize the detailed OS mechanisms involved in the initiation and development of several important diseases. ROS as a double-edged sword in disease progression suggest two different therapeutic strategies to treat redox-relevant diseases, in which targeting ROS sources and redox-related effectors to manipulate redox homeostasis will largely promote precision medicine. Therefore, a comprehensive understanding of the redox signaling networks under physiological and pathological conditions will facilitate the development of redox medicine and benefit patients with redox-relevant diseases.

UPRmt activation improves pathological alterations in cellular models of mitochondrial diseases

Background

Mitochondrial diseases represent one of the most common groups of genetic diseases. With a prevalence greater than 1 in 5000 adults, such diseases still lack effective treatment. Current therapies are purely palliative and, in most cases, insufficient. Novel approaches to compensate and, if possible, revert mitochondrial dysfunction must be developed.

Results

In this study, we tackled the issue using as a model fibroblasts from a patient bearing a mutation in the GFM1 gene, which is involved in mitochondrial protein synthesis. Mutant GFM1 fibroblasts could not survive in galactose restrictive medium for more than 3 days, making them the perfect screening platform to test several compounds. Tetracycline enabled mutant GFM1 fibroblasts survival under nutritional stress. Here we demonstrate that tetracycline upregulates the mitochondrial Unfolded Protein Response (UPR^mt), a compensatory pathway regulating mitochondrial proteostasis. We additionally report that activation of UPR^mt improves mutant GFM1 cellular bioenergetics and partially restores mitochondrial protein expression.

Conclusions

Overall, we provide compelling evidence to propose the activation of intrinsic cellular compensatory mechanisms as promising therapeutic strategy for mitochondrial diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02331-8.

Mitochondrial Dysfunction in Cardiovascular Diseases: Potential Targets for Treatment

Cardiovascular diseases (CVDs) are serious public health issues and are responsible for nearly one-third of global deaths. Mitochondrial dysfunction is accountable for the development of most CVDs. Mitochondria produce adenosine triphosphate through oxidative phosphorylation and inevitably generate reactive oxygen species (ROS). Excessive ROS causes mitochondrial dysfunction and cell death. Mitochondria can protect against these damages via the regulation of mitochondrial homeostasis. In recent years, mitochondria-targeted therapy for CVDs has attracted increasing attention. Various studies have confirmed that clinical drugs (β-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor-II blockers) against CVDs have mitochondrial protective functions. An increasing number of cardiac mitochondrial targets have shown their cardioprotective effects in experimental and clinical studies. Here, we briefly introduce the mechanisms of mitochondrial dysfunction and summarize the progression of mitochondrial targets against CVDs, which may provide ideas for experimental studies and clinical trials.

Empagliflozin-Enhanced Antioxidant Defense Attenuates Lipotoxicity and Protects Hepatocytes by Promoting FoxO3a- and Nrf2-Mediated Nuclear Translocation via the CAMKK2/AMPK Pathway

Lipotoxicity is an important factor in the development and progression of nonalcoholic steatohepatitis. Excessive accumulation of saturated fatty acids can increase the substrates of the mitochondrial electron transport chain in hepatocytes and cause the generation of reactive oxygen species, resulting in oxidative stress, mitochondrial dysfunction, loss of mitochondrial membrane potential, impaired triphosphate (ATP) production, and fracture and fragmentation of mitochondria, which ultimately leads to hepatocellular inflammatory injuries, apoptosis, and necrosis. In this study, we systematically investigated the effects and molecular mechanisms of empagliflozin on lipotoxicity in palmitic acid-treated LO2 cell lines. We found that empagliflozin protected hepatocytes and inhibited palmitic acid-induced lipotoxicity by reducing oxidative stress, improving mitochondrial functions, and attenuating apoptosis and inflammation responses. The mechanistic study indicated that empagliflozin significantly activated adenosine 5'-monophosphate (AMP)-activated protein kinase alpha (AMPKα) through Calcium/Calmodulin dependent protein kinase kinase beta (CAMKK2) instead of liver kinase B1 (LKB1) or TGF-beta activated kinase (TAK1). The activation of empagliflozin on AMPKα not only promoted FoxO3a phosphorylation and thus forkhead box O 3a (FoxO3a) nuclear translocation, but also promoted Nrf2 nuclear translocation. Furthermore, empagliflozin significantly upregulated the expressions of antioxidant enzymes superoxide dismutase (SOD) and HO-1. In addition, empagliflozin did not attenuate lipid accumulation at all. These results indicated that empagliflozin mitigated lipotoxicity in saturated fatty acid-induced hepatocytes, likely by promoting antioxidant defense instead of attenuating lipid accumulation through enhanced FoxO3a and Nrf2 nuclear translocation dependent on the CAMKK2/AMPKα pathway. The CAMKK2/AMPKα pathway might serve as a promising target in treatment of lipotoxicity in nonalcoholic steatohepatitis.

Elaiophylin Inhibits Tumorigenesis of Human Uveal Melanoma by Suppressing Mitophagy and Inducing Oxidative Stress via Modulating SIRT1/FoxO3a Signaling

Uveal melanoma (UM) is the most common primary intraocular tumor in adults, which is associated with poor prognosis. Up to 50% of UM patients develop metastasis. Therapeutics that have proven effective in cutaneous melanoma have little success in treating UM, possibly due to its low mutational burden. Therefore, new drug therapies are highly desired for UM. Our in vitro studies showed that Elaiophylin, a late-stage autophagy inhibitor, exhibited an outstanding anticancer activity in human UM cell lines and human UM primary cells through suppressing mitophagy, inducing oxidative stress and leading to autophagic cell death. Our mechanistic study revealed that Elaiophylin exerted its effect by down-regulating SIRT1 and thus influencing deacetylation and mitochondrial localization of FoxO3a. In our confirmatory experiments, SRT1720, a SIRT1 specific activator, could attenuate Elaiophylin-induced inhibition of mitophagy and elevation of oxidative stress, and such effects was partly reversed by FoxO3a knockdown. Our further in vivo studies showed that Elaiophylin dramatically inhibited tumor growth in the human UM xenograft mouse model, which was accompanied with a decreased SIRT1 expression. Thus, the current study is the first to demonstrate that Elaiophylin has a potent anti-cancer effect against UM, which activity is possibly mediated through regulating SIRT1-FoxO3a signaling axis. And Elaiophylin may be a new and promising drug candidate to treat human UM.

Targeting aging mechanisms: pharmacological perspectives

Geroprotectors slow down aging and promote healthy longevity in model animals. Although hundreds of compounds have been shown to extend the life of laboratory model organisms, clinical studies on potential geroprotectors are exceedingly rare, especially in healthy elders. This review aims to classify potential geroprotectors based on the mechanisms by which they influence aging. These pharmacological interventions can be classified into the following groups: those that prevent oxidation; proteostasis regulators; suppressors of genomic instability; epigenetic drugs; those that preserve mitochondrial function; inhibitors of aging-associated signaling pathways; hormetins; senolytics/senostatics; anti-inflammatory drugs; antifibrotic agents; neurotrophic factors; factors preventing the impairment of barrier function; immunomodulators; and prebiotics, metabiotics, and enterosorbents.

NaAsO2 decreases GSH synthesis by inhibiting GCLC and induces apoptosis through Hela cell mitochondrial damage, mediating the activation of the NF-κB/miR-21 signaling pathway

BACKGROUND

Cervical cancer is the fourth most common cancer in women worldwide, and arsenic has a certain effect in solid tumor chemotherapy. As the rate-limiting enzyme subunit of GSH synthesis, GCLC may be an important target for arsenic to induce apoptosis through mitochondrial apoptosis pathway to exert anti-tumor effect. NF-κB plays an important role in the occurrence and development of cervical cancer and can regulate the expression of GCLC. miR-21 is a potential biomarker of cervical cancer, which can induce apoptosis through ROS regulated the mitochondrial pathway of cells. However, the role of miR-21 in the mitochondrial pathway of cervical cancer cells induced by NaAsO2 through NF-κB/GCLC and GSH synthesis regulated oxidative stress is rarely reported. Therefore, the purpose of this study was to investigate whether NaAsO2 might induce mitochondrial damage and apoptosis of cervical cancer cells through NF-κB/ miR-21 /GCLC induced oxidative stress, and play the anti-tumor role of arsenic as a potential drug for the treatment of cervical cancer.

METHODS

Hela cells were treated with different concentrations of NaAsO2, D, L-Buthionine-(SR)-sulfoximine (BSO), IκBα inhibitor (BAY 11-7082) and miR-21 Inhibitor. CCK-8 assay, Western Blot, qRT PCR, immunofluorescence, transmission electron microscopy, mitochondrial Membrane Potential Assay Kit with JC-1,2',7'-Dichlorofluorescin diacetate fluorescent probe and Annexin V-FITC were used to measure cell activity, GSH and ROS, mitochondrial morphology and membrane potential (ΔΨm), protein and mRNA expression of GCLC, GCLM, p65, IκBα, p-P65, p-I κBα, Bcl-2, BAX, Caspase3, cleaved-caspase3 and miR-21.

RESULTS

Compared with the control group, with the gradual increasing dose of NaAsO2, cell viability was considerable reduced, and increased rate of apoptosis, intracellular GSH level was decreased significantly, ROS was increased, mitochondrial structure was damaged, mitochondrial membrane potential ΔΨm and Bcl2/BAX lowered, the expression of Caspase3 and cleaved-caspase3 were significantly increased, resulting in mitochondrial apoptosis. When Hela cells were treated with 15, 20, and 25 μmol/L NaAsO2, the mRNA and protein levels of GCLC and GCLM were reduced, the expression of p65 in the nucleus was increased, the expression of p-p65/p65, p-IκBα/IκBα and miR-21 were significantly increased. When BSO increased the inhibitory effect of NaAsO2 on GCLC, Compared with NaAsO2 group, the ΔΨm and protein of Bcl-2/BAX, caspase3 and cleaved-capsase3 were increased. When BAY 11-7082 combined with NaAsO2 co-treated, compared with the NaAsO2 group, the protein and mRNA expression of GCLC was increased, NaAsO2-increased expression level of miR-21 was suppressed, and the ΔΨm and cell viability were higher. In addition, compared with the combination of NaAsO2 and miR-21NC, the protein expression of GCLC was increased, the ΔΨm and cell viability reduction were alleviated by miR-21 Inhibitor combined with NaAsO2.

CONCLUSION

NaAsO2 may lead to ROS accumulation in Hela cells and trigger mitochondrial apoptosis. The mechanism may be related to the activation of NF-κB signaling pathway and the promotion of miR-21 expression which leads to the inhibition of GCLC expression and the significant decrease of intracellular reductive GSH synthesis.

Role of Molecular Hydrogen in Ageing and Ageing-Related Diseases

Ageing is a physiological process of progressive decline in the organism function over time. It affects every organ in the body and is a significant risk for chronic diseases. Molecular hydrogen has therapeutic and preventive effects on various organs. It has antioxidative properties as it directly neutralizes hydroxyl radicals and reduces peroxynitrite level. It also activates Nrf2 and HO-1, which regulate many antioxidant enzymes and proteasomes. Through its antioxidative effect, hydrogen maintains genomic stability, mitigates cellular senescence, and takes part in histone modification, telomere maintenance, and proteostasis. In addition, hydrogen may prevent inflammation and regulate the nutrient-sensing mTOR system, autophagy, apoptosis, and mitochondria, which are all factors related to ageing. Hydrogen can also be used for prevention and treatment of various ageing-related diseases, such as neurodegenerative disorders, cardiovascular disease, pulmonary disease, diabetes, and cancer. This paper reviews the basic research and recent application of hydrogen in order to support hydrogen use in medicine for ageing prevention and ageing-related disease therapy.

Modeling the dynamics of energy imbalance: The free radical theory of aging and frailty revisited

The role of oxidative stress in aging and the newly conceptualized vision of frailty is of great interest for the possibility to define a framework able to explain the several modifications observed in all biological molecules along with age. In this review, the impact of oxidative stress is considered in aging processes as well as in frailty, the geriatric concept of declined capacity to cope with any stressor, leading to a status of reduced ability to maintain the homeostatic balance. Although some pharmacological and behavioral approaches have been proposed, we are still lacking efficacious management able to prevent and avoid frailty. This represents a fundamental challenge for future research in this field.

Shaping of Hepatic Ischemia/Reperfusion Events: The Crucial Role of Mitochondria

Hepatic ischemia reperfusion injury (HIRI) is a major hurdle in many clinical scenarios, including liver resection and transplantation. Various studies and countless surgical events have led to the observation of a strong correlation between HIRI induced by liver transplantation and early allograft-dysfunction development. The detrimental impact of HIRI has driven the pursuit of new ways to alleviate its adverse effects. At the core of HIRI lies mitochondrial dysfunction. Various studies, from both animal models and in clinical settings, have clearly shown that mitochondrial function is severely hampered by HIRI and that its preservation or restoration is a key indicator of successful organ recovery. Several strategies have been thus implemented throughout the years, targeting mitochondrial function. This work briefly discusses some the most utilized approaches, ranging from surgical practices to pharmacological interventions and highlights how novel strategies can be investigated and implemented by intricately discussing the way mitochondrial function is affected by HIRI.

Cadmium exposure reprograms energy metabolism of hematopoietic stem cells to promote myelopoiesis at the expense of lymphopoiesis in mice

Cadmium (Cd) is a highly toxic heavy metal in our living environment. Hematopoietic stem cells (HSC) are ancestors for all blood cells. Therefore understanding the impact of Cd on HSC is significant for public health. The aim of this study was to investigate the impact of Cd²⁺ on energy metabolism of HSC and its involvement in hematopoiesis. Wild-type C57BL/6 mice were treated with 10 ppm of Cd²⁺ via drinking water for 3 months, and thereafter glycolysis and mitochondrial (MT) oxidative phosphorylation (OXPHOS) of HSC in the bone marrow (BM) and their impact on hematopoiesis were evaluated. After Cd²⁺ treatment, HSC had reduced lactate dehydrogenase (LDH) activity and lactate production while having increased pyruvate dehydrogenase (PDH) activity, MT membrane potential, ATP production, oxygen (O₂) consumption and reactive oxygen species (ROS), indicating that Cd²⁺ switched the pattern of energy metabolism from glycolysis to OXPHOS in HSC. Moreover, Cd²⁺ switch of HSC energy metabolism was critically dependent on Wnt5a/Cdc42/calcium (Ca²⁺) signaling triggered by a direct action of Cd²⁺ on HSC. To test the biological significance of Cd²⁺ impact on HSC energy metabolism, HSC were intervened for Ca²⁺, OXPHOS, or ROS in vitro, and thereafter the HSC were transplanted into lethally irradiated recipients to reconstitute the immune system; the transplantation assay indicated that Ca²⁺-dependent MT OXPHOS dominated the skewed myelopoiesis of HSC by Cd²⁺ exposure. Collectively, we revealed that Cd²⁺ exposure activated Wnt5a/Cdc42/Ca²⁺ signaling to reprogram the energy metabolism of HSC to drive myelopoiesis at the expense of lymphopoiesis.

Mitochondriotropic antioxidant based on caffeic acid AntiOxCIN4 activates Nrf2-dependent antioxidant defenses and quality control mechanisms to antagonize oxidative stress-induced cell damage

Mitochondria are key organelles involved in cellular survival, differentiation, and death induction. In this regard, mitochondrial morphology and/or function alterations are involved in stress-induced adaptive pathways, priming mitochondria for mitophagy or apoptosis induction. We have previously shown that the mitochondriotropic antioxidant AntiOxCIN₄ (100 μM; 48 h) presented significant cytoprotective effect without affecting the viability of human hepatoma-derived (HepG2) cells. Moreover, AntiOxCIN₄ (12.5 μM; 72 h) caused a mild increase of reactive oxygen species (ROS) levels without toxicity to primary human skin fibroblasts (PHSF). As Nrf2 is a master regulator of the oxidative stress response inducing antioxidant-encoding gene expression, we hypothesized that AntiOxCIN₄ could increase the resistance of human hepatoma-derived HepG2 to oxidative stress by Nrf2-dependent mechanisms, in a process mediated by mitochondrial ROS (mtROS). Here we showed that after an initial decrease in oxygen consumption paralleled by a moderate increase in superoxide anion levels, AntiOxCIN₄ led to a time-dependent Nrf2 translocation to the nucleus. This was followed later by a 1.5-fold increase in basal respiration and a 1.2-fold increase in extracellular acidification. AntiOxCIN₄ treatment enhanced mitochondrial quality by triggering the clearance of defective organelles by autophagy and/or mitophagy, coupled with increased mitochondrial biogenesis. AntiOxCIN₄ also up-regulated the cellular antioxidant defense system. AntiOxCIN₄ seems to have the ability to maintain hepatocyte redox homeostasis, regulating the electrophilic/nucleophilic tone, and preserve cellular physiological functions. The obtained data open a new avenue to explore the effects of AntiOxCIN₄ in the context of preserving hepatic mitochondrial function in disorders, such as NASH/NAFLD and type II diabetes.

Lifespan prolonging mechanisms and insulin upregulation without fat accumulation in long-lived reproductives of a higher termite

Kings and queens of eusocial termites can live for decades, while queens sustain a nearly maximal fertility. To investigate the molecular mechanisms underlying their long lifespan, we carried out transcriptomics, lipidomics and metabolomics in Macrotermes natalensis on sterile short-lived workers, long-lived kings and five stages spanning twenty years of adult queen maturation. Reproductives share gene expression differences from workers in agreement with a reduction of several aging-related processes, involving upregulation of DNA damage repair and mitochondrial functions. Anti-oxidant gene expression is downregulated, while peroxidability of membranes in queens decreases. Against expectations, we observed an upregulated gene expression in fat bodies of reproductives of several components of the IIS pathway, including an insulin-like peptide, Ilp9. This pattern does not lead to deleterious fat storage in physogastric queens, while simple sugars dominate in their hemolymph and large amounts of resources are allocated towards oogenesis. Our findings support the notion that all processes causing aging need to be addressed simultaneously in order to prevent it.

Redox Homeostasis in Well-differentiated Primary Human Nasal Epithelial Cells

Oxidative stress (OS) in the airway epithelium is associated with inflammation, cell damage, and mitochondrial dysfunction that may initiate or worsen respiratory disease. Redox regulation maintains the equilibrium of pro-oxidant/antioxidant reactions but can be disturbed by environmental exposures. The mechanism(s) underlying the induction and impact of OS on airway epithelium and how these influences on respiratory disease is poorly understood. The aim of this study was to develop a stress response model in primary human nasal epithelial cells (NECs) grown at the air-liquid interface (ALI) into a well-differentiated epithelium and to use this model to investigate the mechanisms underlying OS. Hydrogen peroxide (H₂O₂) was used to induce acute OS and the responses were measured with trans epithelial electrical resistance (TEER), membrane permeability, cell death (LDH release), mitochondrial reactive oxygen species (mtROS) generation, redox status (GSH/GSSG ratio), cellular ATP, and signaling pathways (SIRT1, FOXO3, p53, p21, PINK1, PARKIN, NRF2). Following 25 mM (sensitive) or 50mM (resistant) H₂O₂ exposure, cell integrity decreased (p<0.05), GSH/GSSG ratio reduced (p<0.05), and ATP production declined by 83% (p<0.05) in the sensitive and 55% (p<0.05) in the resistant group; mtROS production increased 3.4-fold (p<0.001). Significant inter-individual differences between healthy humans with regards to susceptibility to OS, and differential activation of various pathways (FOXO3, PARKIN) were observed. These intra-individual differences in susceptibility to OS may be attributed to resistant individuals having more mitochondria or greater mitochondrial function.

Long noncoding RNA Gm44593 attenuates oxidative stress from age-related hearing loss by regulating miR-29b/WNK1

Long noncoding RNA has been reported to play important role in various disease. However, the function of lncRNA in age-related hearing loss still unclear. The aim of our study is to investigate the function and mechanism of lncRNA Gm44593 in AHL. ATP content, JC-1 assay, mitochondrial content, cell death rates and dual-luciferase reporter assay were performed to assess the function of lncRNA Gm44593 in HEI-OC1 cells. The expression of lncRNA Gm44593 was significantly upregulated upon H₂O₂ and starvation treatment. Overexpression of lncRNA Gm44593 manifestly reduced the cell death rates. The ATP content, mtDNA content and mitochondrial membrane potential were alleviated upon overexpression of lncRNA Gm44593. We also proved that miR-29b is the direct target of lncRNA Gm44593. Overexpression of miR-29b completely restored the effect induced by lncRNA Gm44593. In addition, we provided evidences that WNK1 is the direct target of miR-29b. Our research uncovers a potential role of lncRNA Gm44593 in age-related hearing loss. We provide new insights into potential therapeutic targets for the amelioration of age-related hearing loss.

Mangiferin Inhibits PDGF-BB-Induced Proliferation and Migration of Rat Vascular Smooth Muscle Cells and Alleviates Neointimal Formation in Mice through the AMPK/Drp1 Axis

Mangiferin is a naturally occurring xanthone C-glycoside that is widely found in various plants. Previous studies have reported that mangiferin inhibits tumor cell proliferation and migration. Excessive proliferation and migration of vascular smooth muscle cells (SMCs) is associated with neointimal hyperplasia in coronary arteries. However, the role and mechanism of mangiferin action in neointimal hyperplasia is still unknown. In this study, a mouse carotid artery ligation model was established, and primary rat smooth muscle cells were isolated and used for mechanistic assays. We found that mangiferin alleviated neointimal hyperplasia, inhibited proliferation and migration of SMCs, and promoted platelets derive growth factors-BB- (PDGF-BB-) induced contractile phenotype in SMCs. Moreover, mangiferin attenuated neointimal formation by inhibiting mitochondrial fission through the AMPK/Drp1 signaling pathway. These findings suggest that mangiferin has the potential to maintain vascular homeostasis and inhibit neointimal hyperplasia.

Mitonuclear interactions alter sex-specific longevity in a species without sex chromosomes

Impaired mitochondrial function can lead to senescence and the ageing phenotype. Theory predicts degenerative ageing phenotypes and mitochondrial pathologies may occur more frequently in males due to the matrilineal inheritance pattern of mitochondrial DNA observed in most eukaryotes. Here, we estimated the sex-specific longevity for parental and reciprocal F1 hybrid crosses for inbred lines derived from two allopatric Tigriopus californicus populations with over 20% mitochondrial DNA divergence. T. californicus lacks sex chromosomes allowing for more direct testing of mitochondrial function in sex-specific ageing. To better understand the ageing mechanism, we estimated two age-related phenotypes (mtDNA content and 8-hydroxy-20-deoxyguanosine (8-OH-dG) DNA damage) at two time points in the lifespan. Sex differences in lifespan depended on the mitochondrial and nuclear backgrounds, including differences between reciprocal F1 crosses which have different mitochondrial haplotypes on a 50 : 50 nuclear background, with nuclear contributions coming from alternative parents. Young females showed the highest mtDNA content which decreased with age, while DNA damage in males increased with age and exceed that of females 56 days after hatching. The adult sex ratio was male-biased and was attributed to complex mitonuclear interactions. Results thus demonstrate that sex differences in ageing depend on mitonuclear interactions in the absence of sex chromosomes.

Pharmacoinformatics-based investigation of bioactive compounds of Rasam (South Indian recipe) against human cancer

Spice-rich recipes are referred to as "functional foods" because they include a variety of bioactive chemicals that have health-promoting properties, in addition to their nutritional value. Using pharmacoinformatics-based analysis, we explored the relevance of bioactive chemicals found in Rasam (a South Indian cuisine) against oxidative stress-induced human malignancies. The Rasam is composed of twelve main ingredients, each of which contains a variety of bioactive chemicals. Sixty-six bioactive compounds were found from these ingredients, and their structures were downloaded from Pubchem. To find the right target via graph theoretical analysis (mitogen-activated protein kinase 6 (MAPK6)) and decipher their signaling route, a network was built. Sixty-six bioactive compounds were used for in silico molecular docking study against MAPK6 and compared with known MAPK6 inhibitor drug (PD-173955). The top four compounds were chosen for further study based on their docking scores and binding energies. In silico analysis predicted ADMET and physicochemical properties of the selected compounds and were used to assess their drug-likeness. Molecular dynamics (MD) simulation modelling methodology was also used to analyse the effectiveness and safety profile of selected bioactive chemicals based on the docking score, as well as to assess the stability of the MAPK6-ligand complex. Surprisingly, the discovered docking scores against MAPK6 revealed that the selected bioactive chemicals exhibit varying binding ability ranges between - 3.5 and - 10.6 kcal mol-1. MD simulation validated the stability of four chemicals at the MAPK6 binding pockets, including Assafoetidinol A (ASA), Naringin (NAR), Rutin (RUT), and Tomatine (TOM). According to the results obtained, fifty of the sixty-six compounds showed higher binding energy (- 6.1 to - 10.6 kcal mol-1), and four of these compounds may be used as lead compounds to protect cells against oxidative stress-induced human malignancies.

Chenodeoxycholic Acid Has Non-Thermogenic, Mitodynamic Anti-Obesity Effects in an In Vitro CRISPR/Cas9 Model of Bile Acid Receptor TGR5 Knockdown

Bile acids (BA) have shown promising effects in animal models of obesity. However, the said effects are thought to rely on a thermogenic effect, which is questionably present in humans. A previous work has shown that the BA chenodeoxycholic acid (CDCA) can revert obesity and accelerate metabolism in animal and cell culture models. Thus, the aim of this study was to understand if this obesity reduction is indeed thermogenically-dependent. A CRISPR/Cas9 model of TGR5 (BA receptor) knockdown in 3T3-L1 adipocytes was developed to diminish thermogenic effects. Various parameters were assessed, including mitochondrial bioenergetics by Seahorse flux analysis, oxidative stress and membrane potential by fluorometry, intermediary metabolism by NMR, protein content assessment by Western Blot, gene expression by qPCR, and confocal microscopy evaluation of mitophagy. CDCA was still capable, for the most part, of reversing the harmful effects of cellular obesity, elevating mitophagy and leading to the reduction of harmed mitochondria within the cells, boosting mitochondrial activity, and thus energy consumption. In summary, CDCA has a non-thermogenic, obesity reducing capacity that hinges on a healthy mitochondrial population, explaining at least some of these effects and opening avenues of human treatment for metabolic diseases.

Sirtuin 3 (SIRT3) Pathways in Age-Related Cardiovascular and Neurodegenerative Diseases

Age-associated cardiovascular and neurodegenerative diseases lead to high morbidity and mortality around the world. Sirtuins are vital enzymes for metabolic adaptation and provide protective effects against a wide spectrum of pathologies. Among sirtuins, mitochondrial sirtuin 3 (SIRT3) is an essential player in preserving the habitual metabolic profile. SIRT3 activity declines as a result of aging-induced changes in cellular metabolism, leading to increased susceptibility to endothelial dysfunction, hypertension, heart failure and neurodegenerative diseases. Stimulating SIRT3 activity via lifestyle, pharmacological or genetic interventions could protect against a plethora of pathologies and could improve health and lifespan. Thus, understanding how SIRT3 operates and how its protective effects could be amplified, will aid in treating age-associated diseases and ultimately, in enhancing the quality of life in elders.

Resveratrol prevents haloperidol-induced mitochondria dysfunction through the induction of autophagy in SH-SY5Y cells

BACKGROUND

Haloperidol is a commonly used antipsychotic drug and may increase neuronal oxidative stress associated with the side effects, including tardive dyskinesia and neurite withdraw. Autophagy plays a protective role in response to the accumulated reactive oxygen species (ROS) induced mitochondria damage. Resveratrol is an antioxidant compound having neuroprotective effects; however, it is unknown if resveratrol may stimulate autophagy and decrease mitochondria damage induced by haloperidol.

HYPOTHESIS

We hypothesis that resveratrol stimulates the autophagic process and protects mitochondria lesion induced by haloperidol.

METHODS

MitoSOX™ Red Mitochondrial Superoxide Indicator and MitoTracker™ Green FM staining were used to measure the amount of the mitochondria ROS production and mitochondria mass in human SH-SY5Y cells treated with haloperidol and/or resveratrol. Autophagic related dyes and Western blot were applied to study the autophagic process and related protein expression. Besides, tandem monomeric mRFP-GFP-LC3 was used to investigate the fusion of autophagosome and lysosome. Transmission electron microscopy was used to investigate the mitochondrial and autophagic ultrastructures with or without haloperidol and resveratrol treatment.

RESULTS

Haloperidol administration significantly increased mitochondria ROS and mitochondrial mass, indicating the increase of mitochondria dysfunction. Although haloperidol increased the autophagosomes and lysosome formation, the autophagosome-lysosome fusion and degradation were impaired. This was because we found an increased p62 after haloperidol treatment, an indication of autophagy incompletion. Importantly, resveratrol promoted the degradation of p62, upregulated the formation of autophagolysosome, and reversed haloperidol-induced mitochondria damage.

CONCLUSION

These results collectively suggest that resveratrol may be introduced as a protective compound against haloperidol-induced mitochondria impairment and aberrant autophagy.

Redox-Mediated Regulation of Mitochondrial Biogenesis, Dynamics, and Respiratory Chain Assembly in Yeast and Human Cells

Mitochondria are double-membrane organelles that contain their own genome, the mitochondrial DNA (mtDNA), and reminiscent of its endosymbiotic origin. Mitochondria are responsible for cellular respiration via the function of the electron oxidative phosphorylation system (OXPHOS), located in the mitochondrial inner membrane and composed of the four electron transport chain (ETC) enzymes (complexes I-IV), and the ATP synthase (complex V). Even though the mtDNA encodes essential OXPHOS components, the large majority of the structural subunits and additional biogenetical factors (more than seventy proteins) are encoded in the nucleus and translated in the cytoplasm. To incorporate these proteins and the rest of the mitochondrial proteome, mitochondria have evolved varied, and sophisticated import machineries that specifically target proteins to the different compartments defined by the two membranes. The intermembrane space (IMS) contains a high number of cysteine-rich proteins, which are mostly imported via the MIA40 oxidative folding system, dependent on the reduction, and oxidation of key Cys residues. Several of these proteins are structural components or assembly factors necessary for the correct maturation and function of the ETC complexes. Interestingly, many of these proteins are involved in the metalation of the active redox centers of complex IV, the terminal oxidase of the mitochondrial ETC. Due to their function in oxygen reduction, mitochondria are the main generators of reactive oxygen species (ROS), on both sides of the inner membrane, i.e., in the matrix and the IMS. ROS generation is important due to their role as signaling molecules, but an excessive production is detrimental due to unwanted oxidation reactions that impact on the function of different types of biomolecules contained in mitochondria. Therefore, the maintenance of the redox balance in the IMS is essential for mitochondrial function. In this review, we will discuss the role that redox regulation plays in the maintenance of IMS homeostasis as well as how mitochondrial ROS generation may be a key regulatory factor for ETC biogenesis, especially for complex IV.

Base excision repair causes age-dependent accumulation of single-stranded DNA breaks that contribute to Parkinson disease pathology

Aging, genomic stress, and mitochondrial dysfunction are risk factors for neurodegenerative pathologies, such as Parkinson disease (PD). Although genomic instability is associated with aging and mitochondrial impairment, the underlying mechanisms are poorly understood. Here, we show that base excision repair generates genomic stress, promoting age-related neurodegeneration in a Caenorhabditis elegans PD model. A physiological level of NTH-1 DNA glycosylase mediates mitochondrial and nuclear genomic instability, which promote degeneration of dopaminergic neurons in older nematodes. Conversely, NTH-1 deficiency protects against α-synuclein-induced neurotoxicity, maintaining neuronal function with age. This apparent paradox is caused by modulation of mitochondrial transcription in NTH-1-deficient cells, and this modulation activates LMD-3, JNK-1, and SKN-1 and induces mitohormesis. The dependance of neuroprotection on mitochondrial transcription highlights the integration of BER and transcription regulation during physiological aging. Finally, whole-exome sequencing of genomic DNA from patients with idiopathic PD suggests that base excision repair might modulate susceptibility to PD in humans.

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Incomplete base excision repair is a source of genomic stress during aging

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The NTH-1 DNA glycosylase is a key mediator of age-dependent genomic instability

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Compromised NTH-1 activity promotes neuroprotection in PD nematodes

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NTH-1 deficiency triggers LMD-3/JNK-1/SKN-1-dependent mitohormetic response

Determination of Antioxidant Activity by Oxygen Radical Absorbance Capacity (ORAC-FL), Cellular Antioxidant Activity (CAA), Electrochemical and Microbiological Analyses of Silver Nanoparticles Using the Aqueous Leaf Extract of Solanum mammosum L

PURPOSE

The importance of studying polyphenolic compounds as natural antioxidants has encouraged the search for new methods of analysis that are quick and simple. The synthesis of silver nanoparticles (AgNPs) using plant extracts has been presented as an alternative to determine the total polyphenolic content and its antioxidant activity.

METHODS

In this study, aqueous leaf extract of Solanum mammosum, a species of plant endemic to South America, was used to produce AgNPs. The technique of oxygen radical absorption capacity using fluorescein (ORAC-FL) was used to measure antioxidant activity. The oxidation of the 2´,7´-dichlorodihydrofluorescein diacetate (DCFH2-DA) as fluorescent probe was used to measure cellular antioxidant activity (CAA). Electrochemical behavior was also examined using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Total polyphenolic content (TPH) was analyzed using the Folin-Ciocalteu method, and the major polyphenolic compound was analyzed by high performance liquid chromatography with diode array detector (HPLC/DAD). Finally, a microbial analysis was conducted using Escherichia coli and Bacillus sp.

RESULTS

The average size of nanoparticles was 5.2 ± 2.3 nm measured by high-resolution transmission electron microscopy (HR-TEM). The antioxidant activity measured by ORAC-FL in the extract and nanoparticles were 3944 ± 112 and 637.5 ± 14.8 µM ET/g of sample, respectively. Cellular antioxidant activity was 14.7 ± 0.2 for the aqueous extract and 12.5 ± 0.2 for the nanoparticles. The electrochemical index (EI) was 402 μA/V for the extract and 324 μA/V for the nanoparticles. Total polyphenolic content was 826.6 ± 20.9 and 139.7 ± 20.9 mg EGA/100 g of sample. Gallic acid was the main polyphenolic compound present in the leaf extract. Microbiological analysis revealed that although leaf extract was not toxic for Escherichia coli and Bacillus sp., minor toxic activity for AgNPs was detected for both strains.

CONCLUSION

It is concluded that the aqueous extract of the leaves of S. mammosum contains nontoxic antioxidant compounds capable of producing AgNPs. The methods using AgNPs can be used as a fast analytical tool to monitor the presence of water-soluble polyphenolic compounds from plant origin. Analysis and detection of new antioxidants from plant extracts may be potentially applicable in biomedicine.

Effects of Siberian fir terpenes extract Abisil on antioxidant activity, autophagy, transcriptome and proteome of human fibroblasts

Background: Abisil is an extract of Siberian fir terpenes with antimicrobial and wound healing activities. Previous studies revealed that Abisil has geroprotective, anti-tumorigenic, and anti-angiogenic effects. Abisil decreased the expression of cyclin D1, E1, A2, and increased the phosphorylation rate of AMPK.

Objective: In the present study, we analyzed the effect of Abisil on autophagy, the mitochondrial potential of embryonic human lung fibroblasts. We evaluated its antioxidant activity and analyzed the transcriptomic and proteomic effects of Abisil treatment.

Results: Abisil treatment resulted in activation of autophagy, reversal of rotenone-induced elevation of reactive oxygen species (ROS) levels and several-fold decrease of mitochondrial potential. Lower doses of Abisil (25 μg/ml) showed a better oxidative effect than high doses (50 or 125 μg/ml). Estimation of metabolic changes after treatment with 50 μg/ml has not shown any changes in oxygen consumption rate, but extracellular acidification rate decreased significantly. Abisil treatment (5 and 50 μg/ml) of MRC5-SV40 cells induced a strong transcriptomic shift spanning several thousand genes (predominantly, expression decrease). Among down-regulated genes, we noticed an over-representation of genes involved in cell cycle progression, oxidative phosphorylation, and fatty acid biosynthesis. Additionally, we observed predominant downregulation of genes encoding for kinases. Proteome profiling also revealed that the content of hundreds of proteins is altered after Abisil treatment (mainly, decreased). These proteins were involved in cell cycle regulation, intracellular transport, RNA processing, translation, mitochondrial organization.

Conclusions: Abisil demonstrated antioxidant and autophagy stimulating activity. Treatment with Abisil results in the predominant downregulation of genes involved in the cell cycle and oxidative phosphorylation.

Mitochondrial Dysfunction in Vascular Wall Cells and Its Role in Atherosclerosis

Altered mitochondrial function is currently recognized as an important factor in atherosclerosis initiation and progression. Mitochondrial dysfunction can be caused by mitochondrial DNA (mtDNA) mutations, which can be inherited or spontaneously acquired in various organs and tissues, having more or less profound effects depending on the tissue energy status. Arterial wall cells are among the most vulnerable to mitochondrial dysfunction due to their barrier and metabolic functions. In atherosclerosis, mitochondria cause alteration of cellular metabolism and respiration and are known to produce excessive amounts of reactive oxygen species (ROS) resulting in oxidative stress. These processes are involved in vascular disease and chronic inflammation associated with atherosclerosis. Currently, the list of known mtDNA mutations associated with human pathologies is growing, and many of the identified mtDNA variants are being tested as disease markers. Alleviation of oxidative stress and inflammation appears to be promising for atherosclerosis treatment. In this review, we discuss the role of mitochondrial dysfunction in atherosclerosis development, focusing on the key cell types of the arterial wall involved in the pathological processes. Accumulation of mtDNA mutations in isolated arterial wall cells, such as endothelial cells, may contribute to the development of local inflammatory process that helps explaining the focal distribution of atherosclerotic plaques on the arterial wall surface. We also discuss antioxidant and anti-inflammatory approaches that can potentially reduce the impact of mitochondrial dysfunction.

Doxycycline promotes proteasome fitness in the central nervous system

Several studies reported that mitochondrial stress induces cytosolic proteostasis in yeast and C. elegans. Notably, inhibition of mitochondrial translation with doxcycyline decreases the toxicity of β-amyloid aggregates, in a C. elegans. However, how mitochondrial stress activates cytosolic proteostasis remains unclear. Further whether doxycycline has this effect in mammals and in disease relevant tissues also remains unclear. We show here that doxycycline treatment in mice drastically reduces the accumulation of proteins destined for degradation by the proteasome in a CNS region-specific manner. This effect is associated with the activation of the ERα axis of the mitochondrial unfolded protein response (UPR^mt), in both males and females. However, sexually dimorphic mechanisms of proteasome activation were observed. Doxycycline also activates the proteasome in fission yeast, where ERα is not expressed. Rather, the ancient ERα-coactivator Mms19 regulates this response in yeast. Our results suggest that the UPR^mt initiates a conserved mitochondria-to-cytosol stress signal, resulting in proteasome activation, and that this signal has adapted during evolution, in a sex and tissue specific-manner. Therefore, while our results support the use of doxycycline in the prevention of proteopathic diseases, they also indicate that sex is an important variable to consider in the design of future clinical trials using doxycycline.

The Interplay Between Mitochondrial Reactive Oxygen Species, Endoplasmic Reticulum Stress, and Nrf2 Signaling in Cardiometabolic Health

Significance: Mitochondria-derived reactive oxygen species (mtROS) are by-products of normal physiology that may disrupt cellular redox homeostasis on a regular basis. Nonetheless, failure to resolve sustained mitochondrial stress to mitigate high levels of mtROS might contribute to the etiology of numerous pathological conditions, such as obesity, insulin resistance, and cardiovascular disease (CVD). Recent Advances: Notably, recent studies have demonstrated that moderate mitochondrial stress might result in the induction of different stress response pathways that ultimately improve the organism's ability to deal with subsequent stress, a process termed mitohormesis. mtROS have been shown to play a key role in regulating this adaptation. Critical Issue: mtROS regulate the convergence of different signaling pathways that, when disturbed, might impair cardiometabolic health. Conversely, mtROS seem to be required to mediate activation of prosurvival pathways, contributing to improved cardiometabolic fitness. In the present review, we will primarily focus on the role of mtROS in the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway and examine the role of endoplasmic reticulum (ER) stress in coordinating the convergence of ER stress and oxidative stress signaling through activation of Nrf2 and activating transcription factor 4 (ATF4). Future Directions: The mechanisms underlying cardiometabolic protection in response to mitochondrial stress have only started to be investigated. Integrated understanding of how mtROS and ER stress cooperatively promote activation of prosurvival pathways might shed mechanistic insight into the role of mitohormesis in mediating cardiometabolic protection and might inform future therapeutic avenues for the treatment of metabolic diseases contributing to CVD. Antioxid. Redox Signal. 35, 252-269.

Mitochondria and Antibiotics: For Good or for Evil?

The discovery and application of antibiotics in the common clinical practice has undeniably been one of the major medical advances in our times. Their use meant a drastic drop in infectious diseases-related mortality and contributed to prolonging human life expectancy worldwide. Nevertheless, antibiotics are considered by many a double-edged sword. Their extensive use in the past few years has given rise to a global problem: antibiotic resistance. This factor and the increasing evidence that a wide range of antibiotics can damage mammalian mitochondria, have driven a significant sector of the medical and scientific communities to advise against the use of antibiotics for purposes other to treating severe infections. Notwithstanding, a notorious number of recent studies support the use of these drugs to treat very diverse conditions, ranging from cancer to neurodegenerative or mitochondrial diseases. In this context, there is great controversy on whether the risks associated to antibiotics outweigh their promising beneficial features. The aim of this review is to provide insight in the topic, purpose for which the most relevant findings regarding antibiotic therapies have been discussed.

Melatonin Ameliorates the Toxicity Induced by Deoxynivalenol in Murine Ovary Granulosa Cells by Antioxidative and Anti-Inflammatory Effects

Melatonin is an important endogenous hormone that shows antioxidant functions and pleiotropic effects, playing a crucial role in animal reproduction. Ovary granulosa cells (GCs) surround the oocyte, which play an important role in regulating oocytes development. Deoxynivalenol (DON) is a common fusarium mycotoxin contaminant of feedstuff and food, posing a serious threat to human and animal reproductive systems. Herein, murine ovary GCs were studied as a reproduction cell model, aimed to assess the protective effect of melatonin on DON-induced toxicity in murine ovary GCs. The results showed that DON adversely affected the viability and growth of murine ovary GCs and increased the apoptosis rate, while melatonin administration ameliorated these toxic effects. We further reveal that DON exposure increased the intracellular reactive oxygen species level, reduced the mitochondrial membrane potential and ATP, and upregulated Tnfα (tumor necrosis factor α), Il6 (interleukin 6), and Il1β (interleukin 1 β) gene expression. Moreover, DON exposure downregulated reproductive hormone gene expression and significantly increased nuclear factor kappa B (p65) activation and mitogen-activated protein kinase phosphorylation. Melatonin treatment attenuated all these effects, suggesting that melatonin protects GCs from the adverse effects of DON by ameliorating oxidative stress, mitochondrial dysfunction, and inflammation. Overall, these results reveal the mechanisms of DON and melatonin in GCs and provide a theoretical basis for melatonin as a drug to improve mycotoxin contamination.

Targeting Mitochondria in Diabetes

Type 2 diabetes (T2D), one of the most prevalent noncommunicable diseases, is often preceded by insulin resistance (IR), which underlies the inability of tissues to respond to insulin and leads to disturbed metabolic homeostasis. Mitochondria, as a central player in the cellular energy metabolism, are involved in the mechanisms of IR and T2D. Mitochondrial function is affected by insulin resistance in different tissues, among which skeletal muscle and liver have the highest impact on whole-body glucose homeostasis. This review focuses on human studies that assess mitochondrial function in liver, muscle and blood cells in the context of T2D. Furthermore, different interventions targeting mitochondria in IR and T2D are listed, with a selection of studies using respirometry as a measure of mitochondrial function, for better data comparison. Altogether, mitochondrial respiratory capacity appears to be a metabolic indicator since it decreases as the disease progresses but increases after lifestyle (exercise) and pharmacological interventions, together with the improvement in metabolic health. Finally, novel therapeutics developed to target mitochondria have potential for a more integrative therapeutic approach, treating both causative and secondary defects of diabetes.

Coordinated Contribution of NADPH Oxidase- and Mitochondria-Derived Reactive Oxygen Species in Metabolic Syndrome and Its Implication in Renal Dysfunction

Metabolic syndrome (MetS), a complex of interrelated risk factors for cardiovascular disease and diabetes, is comprised of central obesity (increased waist circumference), hyperglycemia, dyslipidemia (high triglyceride blood levels, low high-density lipoprotein blood levels), and increased blood pressure. Oxidative stress, caused by the imbalance between pro-oxidant and endogenous antioxidant systems, is the primary pathological basis of MetS. The major sources of reactive oxygen species (ROS) associated with MetS are nicotinamide-adenine dinucleotide phosphate (NADPH) oxidases and mitochondria. In this review, we summarize the current knowledge regarding the generation of ROS from NADPH oxidases and mitochondria, discuss the NADPH oxidase- and mitochondria-derived ROS signaling and pathophysiological effects, and the interplay between these two major sources of ROS, which leads to chronic inflammation, adipocyte proliferation, insulin resistance, and other metabolic abnormalities. The mechanisms linking MetS and chronic kidney disease are not well known. The role of NADPH oxidases and mitochondria in renal injury in the setting of MetS, particularly the influence of the pyruvate dehydrogenase complex in oxidative stress, inflammation, and subsequent renal injury, is highlighted. Understanding the molecular mechanism(s) underlying MetS may lead to novel therapeutic approaches by targeting the pyruvate dehydrogenase complex in MetS and prevent its sequelae of chronic cardiovascular and renal diseases.

Sestrin2 and mitochondrial quality control: Potential impact in myogenic differentiation

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

Exploiting pyocyanin to treat mitochondrial disease due to respiratory complex III dysfunction

Mitochondrial diseases impair oxidative phosphorylation and ATP production, while effective treatment is still lacking. Defective complex III is associated with a highly variable clinical spectrum. We show that pyocyanin, a bacterial redox cycler, can replace the redox functions of complex III, acting as an electron shunt. Sub-μM pyocyanin was harmless, restored respiration and increased ATP production in fibroblasts from five patients harboring pathogenic mutations in TTC19, BCS1L or LYRM7, involved in assembly/stabilization of complex III. Pyocyanin normalized the mitochondrial membrane potential, and mildly increased ROS production and biogenesis. These in vitro effects were confirmed in both Drosophila^TTC19KO and in Danio rerio^TTC19KD, as administration of low concentrations of pyocyanin significantly ameliorated movement proficiency. Importantly, daily administration of pyocyanin for two months was not toxic in control mice. Our results point to utilization of redox cyclers for therapy of complex III disorders.

Metabolic Interactions and Differences between Coronary Heart Disease and Diabetes Mellitus: A Pilot Study on Biomarker Determination and Pathogenesis

Comprehensive understanding of plasma metabotype of diabetes mellitus (DM), coronary heart disease (CHD), and especially diabetes mellitus with coronary heart disease (CHDDM) is still lacking. In this work, the plasma metabolic differences and links of DM, CHD, and CHDDM patients were investigated by the strategy of comparative metabolomics based on ¹H NMR spectroscopy combined with network analysis for revealing their metabolic differences. A total of 17 metabolites are related to three diseases, among which valine, alanine, leucine, isoleucine, and N-acetyl-glycoprotein are positively correlated with CHD and CHDDM (odds ratios (OR) > 1). The trimethylamine oxide, glycerol, lactose, indoleacetate, and scyllo-inositol are closely related to the development of DM to CHDDM (OR > 1), and indoleactate (OR: 1.06, 95% confidence interval (CI): 1.01-1.12) and lactose (OR: 2.46, 95% CI: 1.67-3.25) are particularly prominent in CHDDM. We identified three multi-biomarkers types that were significantly associated with glycosylated hemoglobin (HbA1C) at baseline. All diseases demonstrated dysregulated glycolysis/gluconeogenesis and amino acid biosynthesis pathway. In addition, enrichment in tryptophan metabolism observed in CHDDM, enrichment in inositol phosphate metabolism observed in DM, and the metabolites related to microbiota metabolism were dysregulated in both DM and CHDDM. The comparative metabolomics strategy of multi-diseases offers a new perspective in disease-specific markers and pathogenic pathways.

Mitochondrial Permeability Transition: A Pore Intertwines Brain Aging and Alzheimer's Disease

Advanced age is the greatest risk factor for aging-related brain disorders including Alzheimer's disease (AD). However, the detailed mechanisms that mechanistically link aging and AD remain elusive. In recent years, a mitochondrial hypothesis of brain aging and AD has been accentuated. Mitochondrial permeability transition pore (mPTP) is a mitochondrial response to intramitochondrial and intracellular stresses. mPTP overactivation has been implicated in mitochondrial dysfunction in aging and AD brains. This review summarizes the up-to-date progress in the study of mPTP in aging and AD and attempts to establish a link between brain aging and AD from a perspective of mPTP-mediated mitochondrial dysfunction.

Glucosamine Displays a Potent Caloric Restriction Mimetic Effect in Senescent Rats by Activating Mitohormosis

Aging is strongly correlated with several noncommunicable disorders such as diabetes, obesity, cardiovascular disease, and neurodegenerative conditions. Glucosamine (2-amino-2-deoxy-d-glucose, GlcN) is a naturally occurring amino sugar and is reported to act as a caloric restriction mimetic (CRM). In young and d-galactose-induced accelerated rat aging models, we tested a persistent oral dietary dose of GlcN and evaluated various aging biomarkers in erythrocytes and plasma. A significant increase in the reactive oxygen species (ROS) was observed in GlcN-treated young and accelerated senescent rat model. Increased value of ferric reducing ability of plasma (FRAP), superoxide dismutase, catalase, and plasma membrane redox system (PMRS) was observed. We suggest that GlcN induces a mitohormetic impact by a transient increase in ROS. Our findings indicate that GlcN may be a successful CRM.

Pleiotropic effects of alpha-ketoglutarate as a potential anti-ageing agent

An intermediate of tricarboxylic acid cycle alpha-ketoglutarate (AKG) is involved in pleiotropic metabolic and regulatory pathways in the cell, including energy production, biosynthesis of certain amino acids, collagen biosynthesis, epigenetic regulation of gene expression, regulation of redox homeostasis, and detoxification of hazardous substances. Recently, AKG supplement was found to extend lifespan and delay the onset of age-associated decline in experimental models such as nematodes, fruit flies, yeasts, and mice. This review summarizes current knowledge on metabolic and regulatory functions of AKG and its potential anti-ageing effects. Impact on epigenetic regulation of ageing via being an obligate substrate of DNA and histone demethylases, direct antioxidant properties, and function as mimetic of caloric restriction and hormesis-induced agent are among proposed mechanisms of AKG geroprotective action. Due to influence on mitochondrial respiration, AKG can stimulate production of reactive oxygen species (ROS) by mitochondria. According to hormesis hypothesis, moderate stimulation of ROS production could have rather beneficial biological effects, than detrimental ones, because of the induction of defensive mechanisms that improve resistance to stressors and age-related diseases and slow down functional senescence. Discrepancies found in different models and limitations of AKG as a geroprotective drug are discussed.

What do over-trained athletes and patients with neurodegenerative diseases have in common? Mitochondrial dysfunction

Under pathological conditions and excessive stress, mitochondria may experience a severe and irreversible loss of function. Both strenuous exhaustive exercise and neurodegenerative disorders appear to share defects in mitochondrial function that may fiercely disrupt the integrity and homeostasis of the organelle, leading to perennial pathological substrates. Here, we overview similarities of mitochondrial dysfunction in two conditions and discuss possible areas of interdisciplinary collaboration and research translation between sports medicine and neurology.

The potential role of sestrin 2 in liver regeneration

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

Impairment of sirtuin 1-mediated DNA repair is involved in bisphenol A-induced aggravation of macrophage inflammation and atherosclerosis

Bisphenol A (BPA), an environmental pollutant, has received considerable attention worldwide for its hazardous effects of promoting atherosclerosis and increasing the risk of cardiovascular diseases (CVDs). However, the mechanisms involved are unclear. We aimed to investigate the mechanisms underlying BPA-aggravated atherosclerosis and potential preventive treatments. Four-week-old male Ldlr^-/- C57BL/6 mice were administered 250 μg/L BPA via drinking water for 30 weeks with or without a Western diet and/or resveratrol (RESV) for 12 weeks. Chronic BPA exposure significantly aggravated atherosclerosis, enhanced the production of inflammatory cytokines but not lipid levels, promoted macrophage infiltration into plaque areas. Moreover, peritoneal macrophages isolated from BPA-exposed mice exhibited a more pro-inflammatory phenotype in response to cholesterol crystal treatment than those from control mice. The comet assay revealed that the DNA repair capacity of BPA-exposed macrophages was impaired, and western blotting showed that sirtuin 1 and Nijmegen breakage syndrome 1 (NBS1) expression was reduced. However, restoring sirtuin 1 by RESV administration significantly blocked the BPA-induced decrease in NBS1 and subsequently attenuated the BPA-induced impairment of DNA repair and apoptosis, as indicated by phosphorylated H2AX expression and staining and PARP expression. Moreover, RESV administration significantly ameliorated BPA-aggravated NOD-like receptor pyrin domain 3 and caspase 1 activation and interleukin-1β production, which were abolished by NBS1 knockdown. Furthermore, RESV administration prevented BPA-induced aggravation of atherosclerosis. Our findings indicate that impairment of sirtuin 1-mediated DNA repair is involved in BPA-induced aggravation of macrophage inflammation and atherosclerosis and that RESV might be a promising preventive and therapeutic agent for BPA-related CVDs.

SIRT3 deficiency increases mitochondrial oxidative stress and promotes migration of retinal pigment epithelial cells

Retinal pigment epithelial cells are closely associated with the pathogenesis of diabetic retinopathy. The mechanism by which diabetes impacts retinal pigment epithelial cell function is of significant interest. Sirtuins are an important class of proteins that primarily possess nicotinamide adenine dinucleotide-dependent deacetylases activity and involved in various cellular physiological and pathological processes. Here, we aimed to examine the role of sirtuins in the induction of diabetes-associated retinal pigment epithelial cell dysfunction. High glucose and platelet-derived growth factor (PDGF) treatment induced epithelial-mesenchymal transition and the migration of retinal pigment epithelial cells, and decreased sirtuin-3 expression. Sirtuin-3 knockdown using siRNA increased epithelial-mesenchymal transition and migration of retinal pigment epithelial cells. In contrast, sirtuin-3 overexpression attenuated the effects caused by high glucose and PDGF on epithelial-mesenchymal transition and migration of retinal pigment epithelial cells, suggesting that sirtuin-3 deficiency contributed to retinal pigment epithelial cell dysfunction induced by high glucose and PDGF. Mechanistically, sirtuin-3 deficiency induced retinal pigment epithelial cell dysfunction by the overproduction of mitochondrial reactive oxygen species. These results suggest that sirtuin-3 deficiency mediates the migration of retinal pigment epithelial cells, at least partially by increasing mitochondrial oxidative stress, and shed light on the importance of sirtuin-3 and mitochondrial reactive oxygen species as potential targets in diabetic retinopathy therapy.

Sirtuins as Important Factors in Pathological States and the Role of Their Molecular Activity Modulators

Sirtuins (SIRTs), enzymes from the family of NAD⁺-dependent histone deacetylases, play an important role in the functioning of the body at the cellular level and participate in many biochemical processes. The multi-directionality of SIRTs encourages scientists to undertake research aimed at understanding the mechanisms of their action and the influence that SIRTs have on the organism. At the same time, new substances are constantly being sought that can modulate the action of SIRTs. Extensive research on the expression of SIRTs in various pathological conditions suggests that regulation of their activity may have positive results in supporting the treatment of certain metabolic, neurodegenerative or cancer diseases or this connected with oxidative stress. Due to such a wide spectrum of activity, SIRTs may also be a prognostic markers of selected pathological conditions and prove helpful in assessing their progression, especially by modulating their activity. The article presents and discusses the activating or inhibiting impact of individual SIRTs modulators. The review also gathered selected currently available information on the expression of SIRTs in individual disease cases as well as the biological role that SIRTs play in the human organism, also in connection with oxidative stress condition, taking into account the progress of knowledge about SIRTs over the years, with particular reference to the latest research results.

Roles of mitochondria in the hallmarks of metastasis

Although mitochondrial contributions to cancer have been recognised for approximately a century, given that mitochondrial DNA (mtDNA) is dwarfed by the size of the nuclear genome (nDNA), nuclear genetics has represented a focal point in cancer biology, often at the expense of mtDNA and mitochondria. However, genomic sequencing and advances in in vivo models underscore the importance of mtDNA and mitochondria in cancer and metastasis. In this review, we explore the roles of mitochondria in the four defined 'hallmarks of metastasis': motility and invasion, microenvironment modulation, plasticity and colonisation. Biochemical processes within the mitochondria of both cancer cells and the stromal cells with which they interact are critical for each metastatic hallmark. We unravel complex dynamics in mitochondrial contributions to cancer, which are context-dependent and capable of either promoting metastasis or being leveraged to prevent it at various points of the metastatic cascade. Ultimately, mitochondrial contributions to cancer and metastasis are rooted in the capacity of these organelles to tune metabolic and genetic responses to dynamic microenvironmental cues.

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

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

Blueberry Consumption Challenges Hepatic Mitochondrial Bioenergetics and Elicits Transcriptomics Reprogramming in Healthy Wistar Rats

An emergent trend of blueberries’ (BB) “prophylactic” consumption, due to their phytochemicals’ richness and well-known health-promoting claims, is widely scaled-up. However, the benefits arising from BB indiscriminate intake remains puzzling based on incongruent preclinical and human data. To provide a more in-depth elucidation and support towards a healthier and safer consumption, we conducted a translation-minded experimental study in healthy Wistar rats that consumed BB in a juice form (25 g/kg body weight (BW)/day; 14 weeks’ protocol). Particular attention was paid to the physiological adaptations succeeding in the gut and liver tissues regarding the acknowledged BB-induced metabolic benefits. Systemically, BB boosted serum antioxidant activity and repressed the circulating levels of 3-hydroxybutyrate (3-HB) ketone bodies and 3-HB/acetoacetate ratio. Moreover, BB elicited increased fecal succinic acid levels without major changes on gut microbiota (GM) composition and gut ultra-structural organization. Remarkably, an accentuated hepatic mitochondrial bioenergetic challenge, ensuing metabolic transcriptomic reprogramming along with a concerted anti-inflammatory pre-conditioning, was clearly detected upon long-term consumption of BB phytochemicals. Altogether, the results disclosed herein portray a quiescent mitochondrial-related metabolomics and hint for a unified adaptive response to this nutritional challenge. The beneficial or noxious consequences arising from this dietary trend should be carefully interpreted and necessarily claims future research.

Mitochondrial Dynamics: Fission and Fusion in Fate Determination of Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are pivotal to tissue homeostasis, repair, and regeneration due to their potential for self-renewal, multilineage differentiation, and immune modulation. Mitochondria are highly dynamic organelles that maintain their morphology via continuous fission and fusion, also known as mitochondrial dynamics. MSCs undergo specific mitochondrial dynamics during proliferation, migration, differentiation, apoptosis, or aging. Emerging evidence suggests that mitochondrial dynamics are key contributors to stem cell fate determination. The coordination of mitochondrial fission and fusion is crucial for cellular function and stress responses, while abnormal fission and/or fusion causes MSC dysfunction. This review focuses on the role of mitochondrial dynamics in MSC commitment under physiological and stress conditions. We highlight mechanistic insights into modulating mitochondrial dynamics and mitochondrial strategies for stem cell-based regenerative medicine. These findings shed light on the contribution of mitochondrial dynamics to MSC fate and MSC-based tissue repair.

Nrf-2 as a therapeutic target in acute kidney injury

Multifaceted cellular pathways exhibit a crucial role in the preservation of homeostasis at the molecular, cellular, and organism levels. One of the most important of these protective cascades is Nuclear factor E2-related factor (Nrf-2) that regulates the expression of several genes responsible for cellular detoxification, antioxidant function, anti-inflammation, drug/xenobiotic transportation, and stress-related factors. A growing body of evidence provides information regarding the protective role of Nrf-2 against a number of kidney diseases. Acute kidney injury (AKI) is a substantial clinical problem that causes a huge social burden. In the kidneys, Nrf-2 exerts a dynamic role in improving the injury triggered by inflammation and oxidative stress. Understanding of the exact molecular mechanisms underlying AKI is vital in order to determine the equilibrium between renal adaptation and malfunction and thus reduce disease progression. This review highlights the role of Nrf-2 targeting against AKI and provides evidence that targeting Nrf-2 to prevail oxidative damage and its consequences might exhibit protective effects in kidney diseases.