Mitochondrial ROS and mitochondria-targeted antioxidants in the aged heart

PARP-2 mediates cardiomyocyte aging and damage induced by doxorubicin through SIRT1 Inhibition

Doxorubicin (DOX) is an anthracycline antibiotic used as an antitumor treatment. However, its clinical application is limited due to severe side effects such as cardiotoxicity. In recent years, numerous studies have demonstrated that cellular aging has become a therapeutic target for DOX-induced cardiomyopathy. However, the underlying mechanism and specific molecular targets of DOX-induced cardiomyocyte aging remain unclear. Poly (ADP-ribose) polymerase (PARP) is a family of protein post-translational modification enzymes in eukaryotic cells, including 18 members. PARP-1, the most well-studied member of this family, has become a potential molecular target for the prevention and treatment of various cardiovascular diseases, such as DOX cardiomyopathy and heart failure. PARP-1 and PARP-2 share 69% homology in the catalytic regions. However, they do not entirely overlap in function. The role of PARP-2 in cardiovascular diseases, especially in DOX-induced cardiomyocyte aging, is less studied. In this study, we found for the first time that down-regulation of PARP-2 can inhibit DOX-induced cellular aging in cardiomyocytes. On the contrary, overexpression of PARP-2 can aggravate DOX-induced cardiomyocyte aging and injury. Further research showed that PARP-2 inhibited the expression and activity of SIRT1, which in turn was involved in the development of DOX-induced cardiomyocyte aging and injury. Our findings provide a preliminary experimental basis for establishing PARP-2 as a new target for preventing and treating DOX cardiomyopathy and related drug development.

Bicyclol Alleviates Streptozotocin-induced Diabetic Cardiomyopathy By Inhibiting Chronic Inflammation And Oxidative Stress

PURPOSE

Diabetic cardiomyopathy (DCM) is a common and severe complication of diabetes. Inflammation and oxidative stress play important roles in DCM development. Bicyclol is a hepatoprotective drug in China that exerts anti-inflammatory effects by inhibiting the MAPK and NF-κB pathways to prevent obesity-induced cardiomyopathy. Our purpose was to explore the effect and mechanism of bicyclol on DCM.

METHODS

A type 1 diabetes mouse model was established using C57BL/6 mice by intraperitoneal injection of STZ. The therapeutic effect of bicyclol was evaluated in both heart tissues of diabetic mice and high concentration of glucose (HG)-stimulated H9c2 cells.

RESULTS

We showed that bicyclol significantly attenuated diabetes-induced cardiac hypertrophy and fibrosis, which is accompanied by the preservation of cardiac function in mice. In addition, bicyclol exhibited anti-inflammatory and anti-oxidative effects both in vitro and in vivo. Furthermore, bicyclol inhibited the hyperglycemia-induced activation of MAPKs and NF-κB pathways, while upregulating the Nrf-2/HO-1 pathway to exhibit protective effects.

CONCLUSION

Our data indicate that bicyclol could be a promising cardioprotective agent in the treatment of DCM.

Enhanced TRPC3 transcription through AT1R/PKA/CREB signaling contributes to mitochondrial dysfunction in renal tubular epithelial cells in D-galactose-induced accelerated aging mice

Aging-associated renal dysfunction promotes the pathogenesis of chronic kidney disease. Mitochondrial dysfunction in renal tubular epithelial cells is a hallmark of senescence and leads to accelerated progression of renal disorders. Dysregulated calcium profiles in mitochondria contribute to aging-associated disorders, but the detailed mechanism of this process is not clear. In this study, modulation of the sirtuin 1/angiotensin II type 1 receptor (Sirt1/AT1R) pathway partially attenuated renal glomerular sclerosis, tubular atrophy, and interstitial fibrosis in D-galactose (D-gal)-induced accelerated aging mice. Moreover, modulation of the Sirt1/AT1R pathway improved mitochondrial dysfunction induced by D-gal treatment. Transient receptor potential channel, subtype C, member 3 (TRPC3) upregulation mediated dysregulated cellular and mitochondrial calcium homeostasis during aging. Furthermore, knockdown or knockout (KO) of Trpc3 in mice ameliorated D-gal-induced mitochondrial reactive oxygen species production, membrane potential deterioration, and energy metabolism disorder. Mechanistically, activation of the AT1R/PKA pathway promoted CREB phosphorylation and nucleation of CRE2 binding to the Trpc3 promoter (-1659 to -1648 bp) to enhance transcription. Trpc3 KO significantly improved the renal disorder and cell senescence in D-gal-induced mice. Taken together, these results indicate that TRPC3 upregulation mediates age-related renal disorder and is associated with mitochondrial calcium overload and dysfunction. TRPC3 is a promising therapeutic target for aging-associated renal disorders.

Mitochondrial Dysfunction: A Roadmap for Understanding and Tackling Cardiovascular Aging

Cardiovascular aging is a progressive remodeling process constituting a variety of cellular and molecular alterations that are closely linked to mitochondrial dysfunction. Therefore, gaining a deeper understanding of the changes in mitochondrial function during cardiovascular aging is crucial for preventing cardiovascular diseases. Cardiac aging is accompanied by fibrosis, cardiomyocyte hypertrophy, metabolic changes, and infiltration of immune cells, collectively contributing to the overall remodeling of the heart. Similarly, during vascular aging, there is a profound remodeling of blood vessel structure. These remodeling present damage to endothelial cells, increased vascular stiffness, impaired formation of new blood vessels (angiogenesis), the development of arteriosclerosis, and chronic vascular inflammation. This review underscores the role of mitochondrial dysfunction in cardiac aging, exploring its impact on fibrosis and myocardial alterations, metabolic remodeling, immune response remodeling, as well as in vascular aging in the heart. Additionally, we emphasize the significance of mitochondria-targeted therapies in preventing cardiovascular diseases in the elderly.

Cardioprotective effect of antioxidant combination therapy: A highlight on MitoQ plus alpha-lipoic acid beneficial impact on myocardial ischemia-reperfusion injury in aged rats

Objective

(s): Considering the poor prognosis of ischemic heart disease and the diminished effectiveness of cardioprotective interventions in the elderly, it becomes necessary to investigate the interaction of aging with protection during myocardial ischemia/reperfusion injury (IRI). This study was conducted to assess the impact of mitoquinone (MitoQ) and alpha-lipoic acid (ALA) preconditioning on cardioprotection following IRI in aged rats.

Methods

Fifty aged male Wistar rats (22-24 months old) were divided into five groups including Sham, IR, and treatment groups receiving ALA and/or MitoQ. Treatment groups were received 100 mg/kg/day ALA by oral gavage and/or 10 mg/kg/day MitoQ by intraperitoneal injection for 14 consecutive days. An in vivo model of myocardial IRI was established through ligation of coronary artery for 30 min and it's reopening for 24 h. The left ventricles were removed at the end of reperfusion to assess oxidative stress indicators, mitochondrial function, and expression of mitochondrial dynamic genes. Myocardial infarct size (IS), hemodynamic parameters, and serum lactate dehydrogenase (LDH) level were also measured.

Results

Combination of MitoQ and ALA reduced oxidative stress, LDH level, and IS in aged hearts subjected to IRI. It also enhanced mitochondrial function and upregulated Mfn1, Mfn2, and Foxo1 and downregulated Drp1 and Fis1 gene expression. Co-administration of MitoQ and ALA partially restored IRI-induced hemodynamic changes to normal state. In all measured parameters, the effect of combined treatment was greater than monotherapies.

Conclusion

The combination therapy of MitoQ and ALA demonstrated considerable therapeutic potential in protecting the aging heart against IRI by improving oxidative stress, mitochondrial function, and dynamics in aged rats.

Isolevuglandins Promote Mitochondrial Dysfunction and Electrophysiologic Abnormalities in Atrial Cardiomyocytes

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, yet the cellular and molecular mechanisms underlying the AF substrate remain unclear. Isolevuglandins (IsoLGs) are highly reactive lipid dicarbonyl products that mediate oxidative stress-related injury. In murine hypertension, the lipid dicarbonyl scavenger 2-hydroxybenzylamine (2-HOBA) reduced IsoLGs and AF susceptibility. We hypothesized that IsoLGs mediate detrimental pathophysiologic effects in atrial cardiomyocytes that promote the AF substrate. Using Seahorse XFp extracellular flux analysis and a luminescence assay, IsoLG exposure suppressed intracellular ATP production in atrial HL-1 cardiomyocytes. IsoLGs caused mitochondrial dysfunction, with reduced mitochondrial membrane potential, increased mitochondrial reactive oxygen species (ROS) with protein carbonylation, and mitochondrial DNA damage. Moreover, they generated cytosolic preamyloid oligomers previously shown to cause similar detrimental effects in atrial cells. In mouse atrial and HL-1 cells, patch clamp experiments demonstrated that IsoLGs rapidly altered action potentials (AP), implying a direct effect independent of oligomer formation by reducing the maximum Phase 0 upstroke slope and shortening AP duration due to ionic current modifications. IsoLG-mediated mitochondrial and electrophysiologic abnormalities were blunted or totally prevented by 2-HOBA. These findings identify IsoLGs as novel mediators of oxidative stress-dependent atrial pathophysiology and support the investigation of dicarbonyl scavengers as a novel therapeutic approach to prevent AF.

Hepatocellular carcinoma cells downregulate NADH:Ubiquinone Oxidoreductase Subunit B3 to maintain reactive oxygen species homeostasis

BACKGROUND

HCC is a leading cause of cancer-related death. The role of reactive oxygen species (ROS) in HCC remains elusive. Since a primary ROS source is the mitochondrial electron transport chain complex Ι and the NADH:ubiquinone Oxidoreductase Subunit B3 (NDUFB3), a complex I subunit, is critical for complex I assembly and regulates the associated ROS production, we hypothesize that some HCCs progress by hijacking NDUFB3 to maintain ROS homeostasis.

METHODS

NDUFB3 in human HCC lines was either knocked down or overexpressed. The cells were then analyzed in vitro for proliferation, migration, invasiveness, colony formation, complex I activity, ROS production, oxygen consumption, apoptosis, and cell cycle. In addition, the in vivo growth of the cells was evaluated in nude mice. Moreover, the role of ROS in the NDUFB3-mediated changes in the HCC lines was determined using cellular and mitochondrion-targeted ROS scavengers.

RESULTS

HCC tissues showed reduced NDUFB3 protein expression compared to adjacent healthy tissues. In addition, NDUFB3 knockdown promoted, while its overexpression suppressed, HCC cells' growth, migration, and invasiveness. Moreover, NDUFB3 knockdown significantly decreased, whereas its overexpression increased complex I activity. Further studies revealed that NDUFB3 overexpression elevated mitochondrial ROS production, causing cell apoptosis, as manifested by the enhanced expressions of proapoptotic molecules and the suppressed expression of the antiapoptotic molecule B cell lymphoma 2. Finally, our data demonstrated that the apoptosis was due to the activation of the c-Jun N-terminal kinase (JNK) signaling pathway and cell cycle arrest at G0/G1 phase.

CONCLUSIONS

Because ROS plays essential roles in many biological processes, such as aging and cancers, our findings suggest that NDFUB3 can be targeted for treating HCC and other human diseases.

Toxic effects and potential mechanisms of zinc pyrithione (ZPT) exposure on sperm and testicular injury in zebrafish

Zinc pyrithione (ZPT) is widely recognized for its beneficial properties as an antifouling, antibacterial, and antifungal agent. Despite its positive industrial contributions, ZPT has been proven to exhibit toxicity towards various ecosystems, particularly affecting marine life. However, there is still a dearth of comprehensive research on ZPT toxicity and its toxicological mechanism in reproductive systems of aquatic organisms. In our study, we conducted a thorough analysis and unveiled a multitude of abnormalities in zebrafish sperm and testicular tissue caused by ZPT exposure, including a dose-dependent diminishing of testosterone levels, various sperm deformities, decreased sperm concentration and motility, and ROS-induced testicular tissue DNA damage. In addition, our study suggested that ZPT-induced testicular damage is associated with heightened oxidative stress, apoptosis, and possible hyperpolarization of the mitochondrial membrane. Through RNA-seq analysis, a total of 409 DEGs associated with ZPT-induced testicular injury were identified, and the hub gene was determined using a protein-protein interaction network (PPI). The genes and pathways uncovered in this study point to potential mechanisms of ZPT exposure on sperm and testicular injury in zebrafish.

Dexmedetomidine Ameliorates Cardiac Ischemia/Reperfusion Injury by Enhancing Autophagy Through Activation of the AMPK/SIRT3 Pathway

Objective

Myocardial ischemia-reperfusion (I/R) injury is a detrimental disease, resulting in high morbidity and mortality globally. In this study, we aimed to investigate the role of Dex in mitigating cardiac I/R injury.

Methods

H9c2 cells were treated with Dex (1 μM) for 24 h followed by oxygen-glucose deprivation/re-oxygenation (OGD/R). ANP and BNP mRNA of H9c2 cells and the LDH release were measured. Apoptosis of H9c2 cells was analyzed by flow cytometry. Mitochondrial membrane potential and superoxide production were detected by JC-1 staining and MitoSOXTM Red, respectively. Cell aerobic respiration was measured using Seahorse analysis. In vivo, mice were injected with Dex (25 μg/kg, i.p., once daily) for 5 days and then subjected to heart I/R. Heart function was analyzed by echocardiography. CK-MB and LDH were measured by Elisa. Infarct size was measured using TTC-Evans blue staining. Mitochondrial ultrastructure was observed using transmission electron microscopy. DHE staining, SOD activity, the content of MDA, and the content of GSH/GSSG of heart were measured to evaluate the oxidative stress. In addition, inflammatory cytokines were measured in vivo and in vitro. Furthermore, AMPK, SIRT3, and autophagy-related protein expression in the heart were detected by Western blot.

Results

Dex reduced the H9c2 cells injury exposed to OGD/R, accompanied by improved mitochondrial function and membrane potential. In vivo, Dex improved heart function, myocardial injury, and the mitochondria ultrastructure following I/R injury. Meanwhile, Dex inhibited myocardial oxidative stress and inflammation in the myocardial I/R. Furthermore, Compound C (an AMPK inhibitor) could inhibit Dex-induced autophagy in the I/R heart and the 3-MA (an autophagy inhibitor) could partially interfere with the effects of Dex on the protection of I/R heart.

Conclusion

Dex suppressed oxidative stress and inflammation by promoting autophagy through activating the AMPK/SIRT3 pathway, thus protecting the heart against the I/R injury.

The role of PI3K/AKT signaling pathway in myocardial ischemia-reperfusion injury

Myocardial ischemia has a high incidence and mortality rate, and reperfusion is currently the standard intervention. However, reperfusion may lead to further myocardial damage, known as myocardial ischemia/reperfusion injury (MIRI). There are currently no effective clinical treatments for MIRI. The PI3K/Akt signaling pathway is involved in cardiovascular health and disease and plays an important role in reducing myocardial infarct size and restoring cardiac function after MIRI. Activation of the PI3K/Akt pathway provides myocardial protection through synergistic upregulation of antioxidant, anti-inflammatory, and autophagy activities and inhibition of mitochondrial dysfunction and cardiomyocyte apoptosis. Many studies have shown that PI3K/Akt has a significant protective effect against MIRI. Here, we reviewed the molecular regulation of PI3K/Akt in MIRI and summarized the molecular mechanism by which PI3K/Akt affects MIRI, the effects of ischemic preconditioning and ischemic postconditioning, and the role of related drugs or activators targeting PI3K/Akt in MIRI, providing novel insights for the formulation of myocardial protection strategies. This review provides evidence of the role of PI3K/Akt activation in MIRI and supports its use as a therapeutic target.

Graduate Student Literature Review: Mitochondrial response to heat stress and its implications on dairy cattle bioenergetics, metabolism, and production

The dairy industry depends upon the cow's successful lactation for economic profitability. Heat stress compromises the economic sustainability of the dairy industry by reducing milk production and increasing the risk of metabolic and pathogenic disease. Heat stress alters metabolic adaptations, such as nutrient mobilization and partitioning, that support the energetic demands of lactation. Metabolically inflexible cows are unable to enlist the necessary homeorhetic shifts that provide the needed nutrients and energy for milk synthesis, thereby impairing lactation performance. Mitochondria provide the energetic foundation that enable a myriad of metabolically demanding processes, such as lactation. Changes in an animal's energy requirements are met at the cellular level through alterations in mitochondrial density and bioenergetic capacity. Mitochondria also act as central stress modulators and coordinate tissues' energetic responses to stress by integrating endocrine signals, through mito-nuclear communication, into the cellular stress response. In vitro heat insults affect mitochondria through a compromise in mitochondrial integrity, which is linked to a decrease in mitochondrial function. However, limited evidence exists linking the in vivo metabolic effects of heat stress with parameters of mitochondrial behavior and function in lactating animals. This review summarizes the literature describing the cellular and subcellular effects of heat stress, with a focus on the effect of heat stress on mitochondrial bioenergetics and cellular dysfunction in livestock. Implications for lactation performance and metabolic health are also discussed.

Understanding the role of hyperglycemia and the molecular mechanism associated with diabetic neuropathy and possible therapeutic strategies

Diabetic neuropathy is a neuro-degenerative disorder that encompasses numerous factors that impact peripheral nerves in the context of diabetes mellitus (DM). Diabetic peripheral neuropathy (DPN) is very prevalent and impacts 50% of diabetic patients. DPN is a length-dependent peripheral nerve lesion that primarily causes distal sensory loss, discomfort, and foot ulceration that may lead to amputation. The pathophysiology is yet to be fully understood, but current literature on the pathophysiology of DPN revolves around understanding various signaling cascades involving the polyol, hexosamine, protein-kinase C, AGE, oxidative stress, and poly (ADP ribose) polymerase pathways. The results of research have suggested that hyperglycemia target Schwann cells and in severe cases, demyelination resulting in central and peripheral sensitization is evident in diabetic patients. Various diagnostic approaches are available, but detection at an early stage remains a challenge. Traditional analgesics and opioids that can be used "as required" have not been the mainstay of treatment thus far. Instead, anticonvulsants and antidepressants that must be taken routinely over time have been the most common treatments. For now, prolonging life and preserving the quality of life are the ultimate goals of diabetes treatment. Furthermore, the rising prevalence of DPN has substantial consequences for occupational therapy because such therapy is necessary for supporting wellness, warding off other chronic-diseases, and avoiding the development of a disability; this is accomplished by engaging in fulfilling activities like yoga, meditation, and physical exercise. Therefore, occupational therapy, along with palliative therapy, may prove to be crucial in halting the onset of neuropathic-symptoms and in lessening those symptoms once they have occurred.

Oxidative stress in intervertebral disc degeneration: Molecular mechanisms, pathogenesis and treatment

Low back pain (LBP) is a leading cause of labour loss and disability worldwide, and it also imposes a severe economic burden on patients and society. Among symptomatic LBP, approximately 40% is caused by intervertebral disc degeneration (IDD). IDD is the pathological basis of many spinal degenerative diseases such as disc herniation and spinal stenosis. Currently, the therapeutic approaches for IDD mainly include conservative treatment and surgical treatment, neither of which can solve the problem from the root by terminating the degenerative process of the intervertebral disc (IVD). Therefore, further exploring the pathogenic mechanisms of IDD and adopting targeted therapeutic strategies is one of the current research hotspots. Among the complex pathophysiological processes and pathogenic mechanisms of IDD, oxidative stress is considered as the main pathogenic factor. The delicate balance between reactive oxygen species (ROS) and antioxidants is essential for maintaining the normal function and survival of IVD cells. Excessive ROS levels can cause damage to macromolecules such as nucleic acids, lipids, and proteins of cells, affect normal cellular activities and functions, and ultimately lead to cell senescence or death. This review discusses the potential role of oxidative stress in IDD to further understand the pathophysiological processes and pathogenic mechanisms of IDD and provides potential therapeutic strategies for the treatment of IDD.

Mechanisms of ferroptosis regulating oxidative stress and energy metabolism in myocardial ischemia-reperfusion injury and a novel perspective of natural plant active ingredients for its treatment

Acute myocardial infarction remains the leading cause of death in humans. Timely restoration of blood perfusion to ischemic myocardium remains the most effective strategy in the treatment of acute myocardial infarction, which can significantly reduce morbidity and mortality. However, after restoration of blood flow and reperfusion, myocardial injury will aggravate and induce apoptosis of cardiomyocytes, a process called myocardial ischemia-reperfusion injury. Studies have shown that the loss and death of cardiomyocytes caused by oxidative stress, iron load, increased lipid peroxidation, inflammation and mitochondrial dysfunction, etc., are involved in myocardial ischemia-reperfusion injury. In recent years, with the in-depth research on the pathology of myocardial ischemia-reperfusion injury, people have gradually realized that there is a new form of cell death in the pathological process of myocardial ischemia-reperfusion injury, namely ferroptosis. A number of studies have found that in the myocardial tissue of patients with acute myocardial infarction, there are pathological changes closely related to ferroptosis, such as iron metabolism disorder, lipid peroxidation, and increased reactive oxygen species free radicals. Natural plant products such as resveratrol, baicalin, cyanidin-3-O-glucoside, naringenin, and astragaloside IV can also exert therapeutic effects by correcting the imbalance of these ferroptosis-related factors and expression levels. Combining with our previous studies, this review summarizes the regulatory mechanism of natural plant products intervening ferroptosis in myocardial ischemia-reperfusion injury in recent years, in order to provide reference information for the development of targeted ferroptosis inhibitor drugs for the treatment of cardiovascular diseases.

The immunoproteasome subunit β2i ameliorates myocardial ischemia/reperfusion injury by regulating Parkin-Mfn1/2-mediated mitochondrial fusion

Mitochondrial dynamics are critical for maintaining mitochondrial morphology and function during cardiac ischemia and reperfusion (I/R). The immunoproteasome complex is an inducible isoform of the proteasome that plays a key role in modulating inflammation and some cardiovascular diseases, but the importance of immunoproteasome catalytic subunit β2i (also known as LMP10 or MECL1) in regulating mitochondrial dynamics and cardiac I/R injury is largely unknown. Here, using β2i-knockout (KO) mice and rAAV9-β2i-injected mice, we discovered that β2i expression and its trypsin-like activity were significantly attenuated in the mouse I/R myocardium and in patients with myocardial infarction (MI). Moreover, β2i-KO mice exhibited greatly enhanced I/R-mediated cardiac dysfunction, infarct size, myocyte apoptosis and oxidative stress accompanied by excessive mitochondrial fission due to Mfn1/2 and Drp1 imbalance. Conversely, cardiac overexpression of β2i in mice injected with recombinant adeno-associated virus 9 (rAAV9)-β2i ameliorated cardiac I/R injury. Mechanistically, I/R injury reduced β2i expression and activity, which increased the expression of the E3 ligase Parkin protein and promoted the degradation of mitofusin 1/2 (Mfn1/2), leading to excessive mitochondrial fission. In conclusion, our data suggest for the first time that β2i exerts a protective role against cardiac I/R injury and that increasing β2i expression may be a new therapeutic option for cardiac ischemic disease in clinical practice. Graphical abstract showing how the immunoproteasome subunit β2i ameliorates myocardial I/R injury by regulating Parkin-Mfn1/2-mediated mitochondrial fusion.

Unravelling the Interplay between Cardiac Metabolism and Heart Regeneration

Ischemic heart disease (IHD) is the leading cause of heart failure (HF) and is a significant cause of morbidity and mortality globally. An ischemic event induces cardiomyocyte death, and the ability for the adult heart to repair itself is challenged by the limited proliferative capacity of resident cardiomyocytes. Intriguingly, changes in metabolic substrate utilisation at birth coincide with the terminal differentiation and reduced proliferation of cardiomyocytes, which argues for a role of cardiac metabolism in heart regeneration. As such, strategies aimed at modulating this metabolism-proliferation axis could, in theory, promote heart regeneration in the setting of IHD. However, the lack of mechanistic understanding of these cellular processes has made it challenging to develop therapeutic modalities that can effectively promote regeneration. Here, we review the role of metabolic substrates and mitochondria in heart regeneration, and discuss potential targets aimed at promoting cardiomyocyte cell cycle re-entry. While advances in cardiovascular therapies have reduced IHD-related deaths, this has resulted in a substantial increase in HF cases. A comprehensive understanding of the interplay between cardiac metabolism and heart regeneration could facilitate the discovery of novel therapeutic targets to repair the damaged heart and reduce risk of HF in patients with IHD.

Mitochondrial quality control in cardiac fibrosis: Epigenetic mechanisms and therapeutic strategies

Cardiac fibrosis (CF) is considered an ultimate common pathway of a wide variety of heart diseases in response to diverse pathological and pathophysiological stimuli. Mitochondria are characterized as isolated organelles with a double-membrane structure, and they primarily contribute to and maintain highly dynamic energy and metabolic networks whose distribution and structure exert potent support for cellular properties and performance. Because the myocardium is a highly oxidative tissue with high energy demands to continuously pump blood, mitochondria are the most abundant organelles within mature cardiomyocytes, accounting for up to one-third of the total cell volume, and play an essential role in maintaining optimal performance of the heart. Mitochondrial quality control (MQC), including mitochondrial fusion, fission, mitophagy, mitochondrial biogenesis, and mitochondrial metabolism and biosynthesis, is crucial machinery that modulates cardiac cells and heart function by maintaining and regulating the morphological structure, function and lifespan of mitochondria. Certain investigations have focused on mitochondrial dynamics, including manipulating and maintaining the dynamic balance of energy demand and nutrient supply, and the resultant findings suggest that changes in mitochondrial morphology and function may contribute to bioenergetic adaptation during cardiac fibrosis and pathological remodeling. In this review, we discuss the function of epigenetic regulation and molecular mechanisms of MQC in the pathogenesis of CF and provide evidence for targeting MQC for CF. Finally, we discuss how these findings can be applied to improve the treatment and prevention of CF.

Rhodiola wallichiana var.cholaensis protects against myocardial ischemia-reperfusion injury by attenuating oxidative stress-mediated apoptosis via enhancing Nrf2 signaling

The present study aimed to explore the cardioprotective effects of Rhodiola wallichiana var.cholaensis (RW) against hypoxia/reoxygenation (H/R)-induced H9c2 cell injury and ischemia/reperfusion (I/R)-induced myocardial injury. Following treatment with RW, H9c2 cells were subjected to 4 h of hypoxia/3 h of reoxygenation. MTT assay, LDH assay, and flow cytometry were employed to detect cell viability and changes of ROS and mitochondrial membrane potential. Moreover, after RW treatment, rats underwent 30 min of ischemia, followed by 120 min of reperfusion. Masson and TUNEL staining were performed to measure myocardial damage and apoptosis, respectively. The changes in the levels of proteins were detected by ELISA and western blot. The results showed that RW attenuated the H/R-induced increase in LDH release and loss of the mitochondrial membrane potential, as well as the apoptosis in H9c2 cells. Meanwhile, RW significantly reduces the ST-segment elevation and improves cardiomyocytes' injury, inhibit the apoptosis induced by I/R in rats. Furthermore, RW could decrease the levels of MDA and increase the levels of SOD, T-AOC. GSH-Px and GSH both in vivo and in vitro. Besides, RW increased the expressions of Nrf2, HO-1, ARE and NQO1, and decreased the expressions of Keap1, activating the Nrf2 signaling pathway. Taken together, these results suggested that RW exerts cardioprotection on H/R injury in H9c2 cells and I/R injury in rats by attenuating oxidative stress-mediated apoptosis via enhancing Nrf2 signaling.

Microalgae Produce Antioxidant Molecules with Potential Preventive Effects on Mitochondrial Functions and Skeletal Muscular Oxidative Stress

In recent years, microalgae have become a source of molecules for a healthy life. Their composition of carbohydrates, peptides, lipids, vitamins and carotenoids makes them a promising new source of antioxidant molecules. Skeletal muscle is a tissue that requires constant remodeling via protein turnover, and its regular functioning consumes energy in the form of adenosine triphosphate (ATP), which is produced by mitochondria. Under conditions of traumatic exercise or muscular diseases, a high production of reactive oxygen species (ROS) at the origin of oxidative stress (OS) will lead to inflammation and muscle atrophy, with life-long consequences. In this review, we describe the potential antioxidant effects of microalgae and their biomolecules on mitochondrial functions and skeletal muscular oxidative stress during exercises or in musculoskeletal diseases, as in sarcopenia, chronic obstructive pulmonary disease (COPD) and Duchenne muscular dystrophy (DMD), through the increase in and regulation of antioxidant pathways and protein synthesis.

Mitochondrial Calcium Uniporter Regulator 1 (MCUR1) Relieves Mitochondrial Damage Induced by Lipopolysaccharide by Mediating Mitochondrial Ca2+ Homeostasis in Bovine Mammary Epithelial Cells

The metabolic stress triggered by negative energy balance after calving induces mitochondrial damage of bovine mammary epithelial cells. Mitochondrial calcium uniporter regulator 1 (MCUR1) is a key protein-coding gene that mediates mitochondrial calcium ion (Ca²⁺) uptake and plays an important role in mediating homeostasis of mitochondria. The aim of the present study was to elucidate the effects of MCUR1-mediated Ca²⁺ homeostasis on mitochondria of bovine mammary epithelial cells in response to an inflammatory challenge with lipopolysaccharide (LPS). Exogenous LPS resulted in upregulation of the MCUR1 mRNA and protein abundance, mitochondrial Ca²⁺ content, and mitochondrial reactive oxygen species (Mito-ROS) content while decreasing mitochondrial membrane potential, causing mitochondrial damage, and increasing the rate of apoptosis. Ryanodine pretreatment attenuated the upregulation of the mitochondrial Ca²⁺ content and Mito-ROS content induced by LPS. Overexpression of MCUR1 increased the mitochondrial Ca²⁺ content and Mito-ROS content, while it decreased mitochondrial membrane potential, damaged mitochondria, and induced cell apoptosis. In addition, knockdown of MCUR1 by small interfering RNA attenuated LPS-induced mitochondrial dysfunction by inhibiting mitochondrial Ca²⁺ uptake. Our results revealed that exogenous LPS induces MCUR1-mediated mitochondrial Ca²⁺ overload in bovine mammary epithelial cells, which leads to mitochondrial injury. Thus, MCUR1-mediated Ca²⁺ homeostasis may be a potential therapeutic target against mitochondrial damage induced by metabolic challenges in bovine mammary epithelial cells.

ROS-induced lipid peroxidation modulates cell death outcome: mechanisms behind apoptosis, autophagy, and ferroptosis

Reactive oxygen species (ROS) mediate lipid peroxidation and produce 4-hydroxynonenal and other related products, which play an important role in the process of cell death, including apoptosis, autophagy, and ferroptosis. Lipid peroxidation of phospholipid bilayers can promote mitochondrial apoptosis, endoplasmic reticulum stress, and other complex molecular signaling pathways to regulate apoptosis. Lipid peroxidation and its products also act at different stages of autophagy, affecting the formation of autophagosomes and the recruitment of downstream proteins. In addition, we discuss the important role of ROS and lipid peroxides in ferroptosis and the regulatory role of nuclear factor erythroid 2-related factor 2 in ferroptosis under a background of oxidation. Finally, from the perspectives of promotion, inhibition, transformation, and common upstream molecules, we summarized the crosstalk among apoptosis, autophagy, and ferroptosis in the context of ROS. Our review discusses the role of ROS and lipid peroxidation in apoptosis, autophagy, and ferroptosis and their possible crosstalk mechanisms, so as to provide new insights and directions for the study of diseases related to pathological cell death. This review also has referential significance for studying the exact mechanism of ferroptosis mediated by lipid peroxidation.

In Vitro Probiotic Properties and In Vivo Anti-Ageing Effects of Lactoplantibacillus plantarum PFA2018AU Strain Isolated from Carrots on Caenorhabditis elegans

Lactic acid bacteria (LAB) share and provide several beneficial effects on human health, such as the release of bioactive metabolites, pathogen competition, and immune stimulation. The two major reservoirs of probiotic microorganisms are the human gastro-intestinal tract and fermented dairy products. However, other sources, such as plant-based foods, represent important alternatives thanks to their large distribution and nutritive value. Here, the probiotic potential of autochthonous Lactiplantibacillus plantarum PFA2018AU, isolated from carrots harvested in Fucino highland, Abruzzo (Italy), was investigated through in vitro and in vivo approaches. The strain was sent to the biobank of Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna in Italy for the purpose of patent procedures under the Budapest Treaty. The isolate showed high survival capability under in vitro simulated gastro-intestinal conditions, antibiotic susceptibility, hydrophobicity, aggregation, and the ability to inhibit the in vitro growth of Salmonella enterica serovar Typhimurium, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus pathogens. Caenorhabditis elegans was used as the in vivo model in order to analyse prolongevity and anti-ageing effects. L. plantarum PFA2018AU significantly colonised the gut of the worms, extended their lifespan, and stimulated their innate immunity. Overall, these results showed that autochthonous LAB from vegetables, such as carrots, have functional features that can be considered novel probiotic candidates.

Cardiotoxicity of chloroquine and hydroxychloroquine through mitochondrial pathway

BACKGROUND

Medical therapies can cause cardiotoxicity. Chloroquine (QC) and hydroxychloroquine (HQC) are drugs used in the treatment of malaria and skin and rheumatic disorders. These drugs were considered to help treatment of coronavirus disease (COVID-19) in 2019. Despite the low cost and availability of QC and HQC, reports indicate that this class of drugs can cause cardiotoxicity. The mechanism of this event is not well known, but evidence shows that QC and HQC can cause cardiotoxicity by affecting mitochondria and lysosomes.

METHODS

Therefore, our study was designed to investigate the effects of QC and HQC on heart mitochondria. In order to achieve this aim, mitochondrial function, reactive oxygen species (ROS) level, mitochondrial membrane disruption, and cytochrome c release in heart mitochondria were evaluated. Statistical significance was determined using the one-way and two-way analysis of variance (ANOVA) followed by post hoc Tukey to evaluate mitochondrial succinate dehydrogenase (SDH) activity and cytochrome c release, and Bonferroni test to evaluate the ROS level, mitochondrial membrane potential (MMP) collapse, and mitochondrial swelling.

RESULTS

Based on ANOVA analysis (one-way), the results of mitochondrial SDH activity showed that the IC₅₀ concentration for CQ is 20 µM and for HCQ is 50 µM. Based on two-way ANOVA analysis, the highest effect of CQ and HCQ on the generation of ROS, collapse in the MMP, and mitochondrial swelling were observed at 40 µM and 100 µM concentrations, respectively (p < 0.05). Also, the highest effect of these two drugs has been observed in 60 min (p < 0.05). The statistical results showed that compared to CQ, HCQ is able to cause the release of cytochrome c from mitochondria in all applied concentrations (p < 0.05).

CONCLUSIONS

The results suggest that QC and HQC can cause cardiotoxicity which can lead to heart disorders through oxidative stress and disfunction of heart mitochondria.

Signaling pathways in vascular function and hypertension: molecular mechanisms and therapeutic interventions

Hypertension is a global public health issue and the leading cause of premature death in humans. Despite more than a century of research, hypertension remains difficult to cure due to its complex mechanisms involving multiple interactive factors and our limited understanding of it. Hypertension is a condition that is named after its clinical features. Vascular function is a factor that affects blood pressure directly, and it is a main strategy for clinically controlling BP to regulate constriction/relaxation function of blood vessels. Vascular elasticity, caliber, and reactivity are all characteristic indicators reflecting vascular function. Blood vessels are composed of three distinct layers, out of which the endothelial cells in intima and the smooth muscle cells in media are the main performers of vascular function. The alterations in signaling pathways in these cells are the key molecular mechanisms underlying vascular dysfunction and hypertension development. In this manuscript, we will comprehensively review the signaling pathways involved in vascular function regulation and hypertension progression, including calcium pathway, NO-NOsGC-cGMP pathway, various vascular remodeling pathways and some important upstream pathways such as renin-angiotensin-aldosterone system, oxidative stress-related signaling pathway, immunity/inflammation pathway, etc. Meanwhile, we will also summarize the treatment methods of hypertension that targets vascular function regulation and discuss the possibility of these signaling pathways being applied to clinical work.

D-chiro-inositol increases antioxidant capacity and longevity of Caenorhabditis elegans via activating Nrf-2/SKN-1 and FOXO/DAF-16

D-chiro-inositol (DCI) is an isomer of inositol, abundant in many foods, such as beans and buckwheat, with insulin-sensitizing, anti-inflammatory, and antioxidant effects. DCI has been used to relieve insulin resistance in diabetes and polycystic ovary syndrome in combination with inositol or D-pinitol. Here, we investigated the effect of DCI on aging and stress resistance in C. elegans. We found that DCI could prolong the lifespan of C. elegans by up to 29.6 %. DCI significantly delayed the onset of neurodegenerative diseases in models of C. elegans. DCI decreased the accumulation of Aβ_1-42, alpha-synuclein, and poly-glutamine, the pathological causes of Alzheimer's, Parkinson's, and Huntington's diseases, respectively. DCI significantly increased the stress resistances against pathogens, oxidants and heat shock. Moreover, D-chiro-inositol reduced the content of ROS and malondialdehyde by increasing the total antioxidant capacity and the activity of superoxide dismutase and catalase. Above effects of DCI requires the transcription factors FOXO/DAF-16 and Nrf-2/SKN-1. DCI also increased the expression of downstream genes regulated by FOXO/DAF-16 and Nrf-2/SKN-1. In conclusion, DCI enhanced the antioxidant capacity and healthy lifespan of C. elegans by activating DAF-16, SKN-1, and HSF-1. Our results showed that DCI could be a promising antiaging agent that is worth further research on the mechanism and health supplemental application of DCI.

Mitochondrial dysfunction in macrophages promotes inflammation and suppresses repair after myocardial infarction

Innate immune cells play important roles in tissue injury and repair following acute myocardial infarction (MI). Although reprogramming of macrophage metabolism has been observed during inflammation and resolution phases, the mechanistic link to macrophage phenotype is not fully understood. In this study, we found that myeloid-specific deletion (mKO) of mitochondrial complex I protein, encoded by Ndufs4, reproduced the proinflammatory metabolic profile in macrophages and exaggerated the response to LPS. Moreover, mKO mice showed increased mortality, poor scar formation, and worsened cardiac function 30 days after MI. We observed a greater inflammatory response in mKO mice on day 1 followed by increased cell death of infiltrating macrophages and blunted transition to the reparative phase during post-MI days 3-7. Efferocytosis was impaired in mKO macrophages, leading to lower expression of antiinflammatory cytokines and tissue repair factors, which suppressed the proliferation and activation of myofibroblasts in the infarcted area. Mitochondria-targeted ROS scavenging rescued these impairments, improved myofibroblast function in vivo, and reduced post-MI mortality in mKO mice. Together these results reveal a critical role of mitochondria in inflammation resolution and tissue repair via modulation of efferocytosis and crosstalk with fibroblasts. These findings have potential significance for post-MI recovery as well as for other inflammatory conditions.

Interaction of Cardiovascular Nonmodifiable Risk Factors, Comorbidities and Comedications With Ischemia/Reperfusion Injury and Cardioprotection by Pharmacological Treatments and Ischemic Conditioning

Preconditioning, postconditioning, and remote conditioning of the myocardium enhance the ability of the heart to withstand a prolonged ischemia/reperfusion insult and the potential to provide novel therapeutic paradigms for cardioprotection. While many signaling pathways leading to endogenous cardioprotection have been elucidated in experimental studies over the past 30 years, no cardioprotective drug is on the market yet for that indication. One likely major reason for this failure to translate cardioprotection into patient benefit is the lack of rigorous and systematic preclinical evaluation of promising cardioprotective therapies prior to their clinical evaluation, since ischemic heart disease in humans is a complex disorder caused by or associated with cardiovascular risk factors and comorbidities. These risk factors and comorbidities induce fundamental alterations in cellular signaling cascades that affect the development of ischemia/reperfusion injury and responses to cardioprotective interventions. Moreover, some of the medications used to treat these comorbidities may impact on cardioprotection by again modifying cellular signaling pathways. The aim of this article is to review the recent evidence that cardiovascular risk factors as well as comorbidities and their medications may modify the response to cardioprotective interventions. We emphasize the critical need for taking into account the presence of cardiovascular risk factors as well as comorbidities and their concomitant medications when designing preclinical studies for the identification and validation of cardioprotective drug targets and clinical studies. This will hopefully maximize the success rate of developing rational approaches to effective cardioprotective therapies for the majority of patients with multiple comorbidities. SIGNIFICANCE STATEMENT: Ischemic heart disease is a major cause of mortality; however, there are still no cardioprotective drugs on the market. Most studies on cardioprotection have been undertaken in animal models of ischemia/reperfusion in the absence of comorbidities; however, ischemic heart disease develops with other systemic disorders (e.g., hypertension, hyperlipidemia, diabetes, atherosclerosis). Here we focus on the preclinical and clinical evidence showing how these comorbidities and their routine medications affect ischemia/reperfusion injury and interfere with cardioprotective strategies.

The Fractal Viewpoint of Tumors and Nanoparticles

Even though the promising therapies against cancer are rapidly improved, the oncology patients population has seen exponential growth, placing cancer in 5th place among the ten deadliest diseases. Efficient drug delivery systems must overcome multiple barriers and maximize drug delivery to the target tumors, simultaneously limiting side effects. Since the first observation of the quantum tunneling phenomenon, many multidisciplinary studies have offered quantum-inspired solutions to optimized tumor mapping and efficient nanodrug design. The property of a wave function to propagate through a potential barrier offer the capability of obtaining 3D surface profiles using imaging of individual atoms on the surface of a material. The application of quantum tunneling on a scanning tunneling microscope offers an exact surface roughness mapping of tumors and pharmaceutical particles. Critical elements to cancer nanotherapeutics apply the fractal theory and calculate the fractal dimension for efficient tumor surface imaging at the atomic level. This review study presents the latest biological approaches to cancer management based on fractal geometry.

Downregulation of Sirt6 by CD38 promotes cell senescence and aging

Decreased nicotinamide adenine dinucleotide (NAD+) levels accompany aging. CD38 is the main cellular NADase. Cyanidin-3-O-glucoside (C3G), a natural inhibitor of CD38, is a well-known drug that extends the human lifespan. We investigated mechanisms of CD38 in cell senescence and C3G in antiaging. Myocardial H9c2 cells were induced to senescence with D-gal. CD38 siRNA, C3G and UBCS039 (a chemical activator of Sirt6) inhibited D-gal-induced senescence by reducing reactive oxygen species, hexokinase 2 and SA-β-galactosidase levels. These activators also stimulated cell proliferation and telomerase reverse transcriptase levels, while OSS-128167 (a chemical inhibitor of Sirt6) and Sirt6 siRNA exacerbated the senescent process. H9c2 cells that underwent D-gal-induced cell senescence increased CD38 expression and decreased Sirt6 expression; CD38 siRNA and C3G decreased CD38 expression and increased Sirt6 expression, respectively; and Sirt6 siRNA stimulated cell senescence in the presence of C3G and CD38 siRNA. In D-gal-induced acute aging mice, CD38 and Sirt6 exhibited increased and decreased expression, respectively, in myocardial tissues, and C3G treatment decreased CD38 expression and increased Sirt6 expression in the tissues. C3G also reduced IL-1β, IL-6, IL-17A, TNF-α levels and restored NAD+ and NK cell levels in the animals. We suggest that CD38 downregulates Sirt6 expression to promote cell senescence and C3G exerts an antiaging effect through CD38-Sirt6 signaling.

Mitochondrial dysfunction and autophagy activation are associated with cardiomyopathy developed by extended methamphetamine self-administration in rats

The recent rise in illicit use of methamphetamine (METH), a highly addictive psychostimulant, is a huge health care burden due to its central and peripheral toxic effects. Mounting clinical studies have noted that METH use in humans is associated with the development of cardiomyopathy; however, preclinical studies and animal models to dissect detailed molecular mechanisms of METH-associated cardiomyopathy development are scarce. The present study utilized a unique very long-access binge and crash procedure of METH self-administration to characterize the sequelae of pathological alterations that occur with METH-associated cardiomyopathy. Rats were allowed to intravenously self-administer METH for 96 h continuous weekly sessions over 8 weeks. Cardiac function, histochemistry, ultrastructure, and biochemical experiments were performed 24 h after the cessation of drug administration. Voluntary METH self-administration induced pathological cardiac remodeling as indicated by cardiomyocyte hypertrophy, myocyte disarray, interstitial and perivascular fibrosis accompanied by compromised cardiac systolic function. Ultrastructural examination and native gel electrophoresis revealed altered mitochondrial morphology and reduced mitochondrial oxidative phosphorylation (OXPHOS) supercomplexes (SCs) stability and assembly in METH exposed hearts. Redox-sensitive assays revealed significantly attenuated mitochondrial respiratory complex activities with a compensatory increase in pyruvate dehydrogenase (PDH) activity reminiscent of metabolic remodeling. Increased autophagy flux and increased mitochondrial antioxidant protein level was observed in METH exposed heart. Treatment with mitoTEMPO reduced the autophagy level indicating the involvement of mitochondrial dysfunction in the adaptive activation of autophagy in METH exposed hearts. Altogether, we have reported a novel METH-associated cardiomyopathy model using voluntary drug seeking behavior. Our studies indicated that METH self-administration profoundly affects mitochondrial ultrastructure, OXPHOS SCs assembly and redox activity accompanied by increased PDH activity that may underlie observed cardiac dysfunction.

Synthesis and characterization of protocatechuic acid grafted carboxymethyl chitosan with oxidized sodium alginate hydrogel through the Schiff's base reaction

Excessive accumulation of free radicals is closely related to the occurrence and development of various neurodegenerative diseases. In this study, a novel protocatechuic acid grafted carboxymethyl chitosan with oxidized sodium alginate (PCA-g-CMCS/OSA) hydrogel was developed to maintain the oxidation-antioxidation balance activities. By optimizing the pH-soluble range (pH > 6.4) of CMCS, PCA was grafted onto CMCS skeleton via EDC/NHS, and then conjugated with aldehyde group of OSA to form Schiff's base hydrogel at physiological temperature. The gelation time can be adjusted rapidly within 1-3 min by controlling the content of OSA. The shaped hydrogel exhibited porous network structure with high porosity (>90 %), swelling ratio (2000-3000 %) and rheological property, which is beneficial to cell growth and proliferation. The conjugates preserved excellent DPPH and ABTS radicals scavenging abilities and adequate biodegradability within 5 weeks. Moreover, with the release of PCA monomer due to degradation of the PCA-g-CMCS/OSA, the hydrogel also exhibited excellent biocompatibility and protective effect on H2O2-induced oxidative damage in PC12 cells. These results suggested that the PCA-g-CMCS/OSA hydrogel would appear to be a more attractive candidate for potential biomedical applications such as antioxidant drug release and tissue engineering implant material.

Functional Regulation of KATP Channels and Mutant Insight Into Clinical Therapeutic Strategies in Cardiovascular Diseases

ATP-sensitive potassium channels (K_ATP channels) play pivotal roles in excitable cells and link cellular metabolism with membrane excitability. The action potential converts electricity into dynamics by ion channel-mediated ion exchange to generate systole, involved in every heartbeat. Activation of the K_ATP channel repolarizes the membrane potential and decreases early afterdepolarization (EAD)-mediated arrhythmias. K_ATP channels in cardiomyocytes have less function under physiological conditions but they open during severe and prolonged anoxia due to a reduced ATP/ADP ratio, lessening cellular excitability and thus preventing action potential generation and cell contraction. Small active molecules activate and enhance the opening of the K_ATP channel, which induces the repolarization of the membrane and decreases the occurrence of malignant arrhythmia. Accumulated evidence indicates that mutation of K_ATP channels deteriorates the regulatory roles in mutation-related diseases. However, patients with mutations in K_ATP channels still have no efficient treatment. Hence, in this study, we describe the role of K_ATP channels and subunits in angiocardiopathy, summarize the mutations of the K_ATP channels and the functional regulation of small active molecules in K_ATP channels, elucidate the potential mechanisms of mutant K_ATP channels and provide insight into clinical therapeutic strategies.

Interplay between Zn2+ Homeostasis and Mitochondrial Functions in Cardiovascular Diseases and Heart Ageing

Zinc plays an important role in cardiomyocytes, where it exists in bound and histochemically reactive labile Zn²⁺ forms. Although Zn²⁺ concentration is under tight control through several Zn²⁺-transporters, its concentration and intracellular distribution may vary during normal cardiac function and pathological conditions, when the protein levels and efficacy of Zn²⁺ transporters can lead to zinc re-distribution among organelles in cardiomyocytes. Such dysregulation of cellular Zn²⁺ homeostasis leads to mitochondrial and ER stresses, and interrupts normal ER/mitochondria cross-talk and mitophagy, which subsequently, result in increased ROS production and dysregulated metabolic function. Besides cardiac structural and functional defects, insufficient Zn²⁺ supply was associated with heart development abnormalities, induction and progression of cardiovascular diseases, resulting in accelerated cardiac ageing. In the present review, we summarize the recently identified connections between cellular and mitochondrial Zn²⁺ homeostasis, ER stress and mitophagy in heart development, excitation–contraction coupling, heart failure and ischemia/reperfusion injury. Additionally, we discuss the role of Zn²⁺ in accelerated heart ageing and ageing-associated rise of mitochondrial ROS and cardiomyocyte dysfunction.

Aging, sex and NLRP3 inflammasome in cardiac ischaemic disease

Experimentally, many strong cardioprotective treatments have been identified in different animal models of acute ischaemia/reperfusion injury (IRI) and coronary artery disease (CAD). However, the translation of these cardioprotective therapies for the benefit of the patients into the clinical scenario has been very disappointing. The reasons for this lack are certainly multiple. Indeed, many confounding factors we must deal in clinical reality, such as aging, sex and inflammatory processes are neglected in many experiments. Due to the pivotal role of aging, sex and inflammation in determining cardiac ischaemic disease, in this review, we take into account age as a modifier of tolerance to IRI in the two sexes, dissecting aging and myocardial reperfusion injury mechanisms and the sex differences in tolerance to IRI. Then we focus on the role of the gut microbiota and the NLRP3 inflammasome in myocardial IRI and on the possibility to consider NLRP3 inflammasome as a potential target in the treatment of CAD in relationship with age and sex. Finally, we consider the cardioprotective mechanisms and cardioprotective treatments during aging in the two sexes.

Myocardial ischemia/reperfusion injury: Mechanisms of injury and implications for management (Review)

Myocardial infarction is one of the primary causes of mortality in patients with coronary heart disease worldwide. Early treatment of acute myocardial infarction restores blood supply of ischemic myocardium and decreases the mortality risk. However, when the interrupted myocardial blood supply is recovered within a certain period of time, it causes more serious damage to the original ischemic myocardium; this is known as myocardial ischemia/reperfusion injury (MIRI). The pathophysiological mechanisms leading to MIRI are associated with oxidative stress, intracellular calcium overload, energy metabolism disorder, apoptosis, endoplasmic reticulum stress, autophagy, pyroptosis, necroptosis and ferroptosis. These interplay with one another and directly or indirectly lead to aggravation of the effect. In the past, apoptosis and autophagy have attracted more attention but necroptosis and ferroptosis also serve key roles. However, the mechanism of MIRI has not been fully elucidated. The present study reviews the mechanisms underlying MIRI. Based on current understanding of the pathophysiological mechanisms of MIRI, the association between cell death-associated signaling pathways were elaborated, providing direction for investigation of novel targets in clinical treatment.

Oxidative Stress Contributes to Cytoskeletal Protein Degradation of Esox lucius through Activation of Mitochondrial Apoptosis during Postmortem Storage

This study investigated the role of oxidative stress in the mitochondrial apoptotic pathways and structural protein degradation of fish during postmortem storage by measuring oxidative stress levels, mitochondrial antioxidant enzyme activity, mitochondrial dysfunction, apoptotic factors, and structural protein degradation (n = 3). The results revealed that reactive oxygen species (ROS) increased gradually within the first 12 h and then decreased (p < 0.05) in mitochondria. Lipid peroxidation was increased, and superoxide dismutase, catalase, and glutathione peroxidase activities were decreased in mitochondria (p < 0.05). Furthermore, oxidative stress induced mitochondrial membrane opening, mitochondrial swelling, as well as the depolarization of mitochondrial potential. This led to an increase in the release of cytochrome c from mitochondria and caspase-3 activation. Ultimately, oxidative stress promoted small protein degradation (troponin-T and desmin) and induced myofibril susceptibility to proteolysis. These observations confirmed that oxidative stress mediated the activation of mitochondrial apoptotic factors-promoted protein degradation, initiating the deterioration of fish muscle through the mitochondrial apoptotic pathway.

Ultrafine black carbon caused mitochondrial oxidative stress, mitochondrial dysfunction and mitophagy in SH-SY5Y cells

Exposure to ambient ultrafine black carbon (uBC, with aerodynamic diameter less than 100 nm) is associated with many neurodegenerative diseases. Oxidative stress is the predominantly reported neurotoxic effects caused by uBC exposure. Mitochondrion is responsible for production of majority of ROS in cells and mitochondrial dysfunction is closely related to adverse nervous outcomes. Mitophagy is an important cellular process to eliminate dysfunctional or damaged mitochondria. However, the mechanisms that modulate mitophagy and mitochondrial dysfunction initiated by uBC remain to be elucidated. The purpose of this study was to investigate how mitochondrial oxidative stress regulated mitochondrial dysfunction and mitophagy in human neuroblastoma cell line (SH-SY5Y) after uBC treatment. RNA interference was further applied to explore the roles of mitophagy in mitochondrial dysfunction. We found uBC triggered cell apoptosis via ROS-mitochondrial apoptotic pathway. The uBC also caused serious mitochondrial damage and respiratory dysfunction, indicated by the abnormalities in mitochondrial division and fusion related proteins, decreased mitochondria number and ATP level. Increased PTEN induced putative kinase 1 (PINK1) and Parkin protein levels and the autolysosome numbers suggested uBC could promote Pink1/Parkin-dependent mitophagy process in SH-SY5Y cells. Mitophagy inhibition could reserve mitochondria number and ATP activity, but not fusion and division related protein levels in SH-SY5Y cells exposed to uBC. Administration of a mitochondria-targeted antioxidant (mitoquinone) significantly eliminated uBC caused apoptosis, mitochondrial dysfunction and mitophagy. Our data suggested mitochondrial oxidative stress regulated uBC induced mitochondrial dysfunction and PINK1/Parkin-dependent mitophagy. PINK1/Parkin-dependent mitophagy probably participated in regulating uBC caused mitochondrial dysfunction but not by controlling mitochondrial fusion and division related proteins. Our results may provide some new insights and evidences to understand the mechanisms of neurotoxicity induced by uBC.

Mechanism of Longevity Extension of Caenorhabditis elegans Induced by Schizophyllum commune Fermented Supernatant With Added Radix Puerariae

Schizophyllum commune (S. commune) fermented supernatant with added Radix Puerariae (SC-RP) showed significant antioxidant activity in our previous work. However, the possible lifespan and healthspan extending the capacity of Caenorhabditis elegans (C. elegans) and the underlying mechanism were not illuminated. In this study, the effect of SC-RP on extending the lifespan and improving stress resistance of C. elegans were examined. Additionally, the underlying lifespan extending molecular mechanisms of SC-RP were explored. Treated with SC-RP at 10 μg/mL, the lifespan of C. elegans increased by 24.89% (P &lt; 0.01). Also, SC-RP prolonged the healthspan of the nematode, including reducing lipofuscin levels, improving mobility and enhancing resistance to oxidative stress and heat shock. Moreover, superoxide dismutase and catalase activities were increased for SC-RP treated C. elegans. Meantime the intracellular levels of thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) were attenuated. Express levels of eight genes including daf-2, daf-16, sod-3, skn-1, gst-4, clk-1, age-1 and mev-1 were analyzed by RT-PCR method for possible C. elegan anti-aging mechanisms of SC-RP. Expression levels of key genes daf-2, gst-4 and sod-3 were up-regulated, while that of daf-16, skn-1, and clk-1 were down-regulated. The results suggest that SC-RP could extend the lifespan and healthspan of C. elegans significantly, and the IIS pathway, SKN-1/Nrf2 pathway and mitochondrial metabolism pathway were primarily considered associated. Thus, SC-RP is a potential component to improve aging and aging-related symptoms as new functional materials.

Protective role of hydrogen sulfide against diabetic cardiomyopathy via alleviating necroptosis

Diabetic cardiomyopathy lacks effective and novel methods. Hydrogen sulfide (H₂S) as the third gasotransmitter plays an important role in the cardiovascular system. Our study was to elucidate the protective effect and possible mechanism of H₂S on diabetic cardiomyopathy from the perspective of necroptosis. Leptin receptor deficiency (db/db) mice and streptozotocin (STZ)-induced diabetic cystathionine-γ-lyase (CSE) knockout (KO) mice were investigated. In addition, cardiomyocytes were stimulated with high glucose. We found that plasma H₂S level, myocardial H₂S production and CSE mRNA expression was impaired in the diabetic mice. CSE deficiency exacerbated diabetic cardiomyopathy, and promoted myocardial oxidative stress, necroptosis and inflammasome in STZ-induced mice. CSE inhibitor dl-propargylglycine (PAG) aggravated cell damage and oxidative stress, deteriorated necroptosis and inflammasome in cardiomyocytes with high glucose stimulation. H₂S donor sodium hydrosulfide (NaHS) improved diabetic cardiomyopathy, attenuated myocardial oxidative stress, necroptosis and the NLR family pyrin domain-containing protein 3 (NLRP3) in db/db mice. NaHS also alleviated cell damage, oxidative stress, necroptosis and inflammasome in cardiomyocytes with high glucose stimulation. In Conclusion, H₂S deficiency aggravated mitochondrial damage, increased reactive oxygen species accumulation, promoted necroptosis, activated NLRP3 inflammasome, and finally exacerbated diabetic cardiomyopathy. Exogenous H₂S supplementation alleviated necroptosis to suppress NLRP3 inflammasome activation and attenuate diabetic cardiomyopathy via mitochondrial dysfunction improvement and oxidative stress inhibition. Our study provides the first evidence and a new mechanism that necroptosis inhibition by a pharmacological manner of H₂S administration protected against diabetic cardiomyopathy. It is beneficial to provide a novel strategy for the prevention and treatment of diabetic cardiomyopathy.

Sirtuin 3: Emerging therapeutic target for cardiovascular diseases

Acetylation is one of the most important methods of modification that lead to a change in the function of proteins. In humans, metabolic enzymes commonly undergo acetylation, which regulates the activities of metabolic enzymes and metabolic pathways. Sirtuin 3 (SIRT3) is a prominent deacetylase that participates in mitochondrial metabolism, redox balance, and mitochondrial dynamics by regulating mitochondrial protein acetylation, thereby protecting mitochondria from damage. Normal mitochondrial function is essential for maintaining the metabolism and function of the heart. Therefore, mitochondrial dysfunction caused by SIRT3 consumption and defects leads to the development of a variety of cardiovascular diseases. A comprehensive understanding of the role of SIRT3 in cardiovascular disease is critical for developing new therapeutic strategies. Herein, we summarize the function of SIRT3 in mitochondria, the complex mechanisms mediating cardiovascular diseases, and the potential value of SIRT3 small-molecule agonists in future clinical treatments.

Multidimensional bioresponses in nematodes contribute to the antagonistic toxic interaction between pentachlorophenol and TiO2 nanoparticles in soil

Interactions between nanomaterials (NMs) and coexisting contaminants are important contributors to their joint biological effects, while the reverse actions of bioresponses in determining the toxic interaction between NMs and contaminants were rarely understood. Here, we investigated the toxic interaction and mechanism between TiO₂ NMs (nTiO₂) and pentachlorophenol (PCP) in soil using the model nematode (Caenorhabditis elegans). PCP (0.5-50 mg/kg) and nTiO₂ (50-5000 mg/kg) co-exposures induced antagonistic effects on the survival, growth, and locomotion of nematodes, and the levels of ultrastructural damage and oxidative stress exhibited consistent alterations. Soil PCP concentrations changed insignificantly after the single or combined exposures, indicating a negligible direct interaction between PCP and nTiO₂ under the soil condition. Transcriptomic analysis revealed that after 50 mg/kg PCP exposure, half of differentially expressed genes were involved in epidermal collagen synthesis, while the PCP-nTiO₂ co-exposure particularly activated genes related to antistress responses and the positive regulation of physiological functions. Further biochemical analysis demonstrated the antagonistic interactions were derived from two aspects: 1) PCP-induced epidermal collagen incrassation lowered the bioaccumulation and toxicity of nTiO₂; 2) nTiO₂-activated glutathione detoxification pathway alleviated PCP-induced toxicity. These findings highlight the key role of bioresponses in determining toxic interactions between NMs and co-contaminants.

The Role of Oxidative Stress in the Aging Heart

Medical advances and the availability of diagnostic tools have considerably increased life expectancy and, consequently, the elderly segment of the world population. As age is a major risk factor in cardiovascular disease (CVD), it is critical to understand the changes in cardiac structure and function during the aging process. The phenotypes and molecular mechanisms of cardiac aging include several factors. An increase in oxidative stress is a major player in cardiac aging. Reactive oxygen species (ROS) production is an important mechanism for maintaining physiological processes; its generation is regulated by a system of antioxidant enzymes. Oxidative stress occurs from an imbalance between ROS production and antioxidant defenses resulting in the accumulation of free radicals. In the heart, ROS activate signaling pathways involved in myocyte hypertrophy, interstitial fibrosis, contractile dysfunction, and inflammation thereby affecting cell structure and function, and contributing to cardiac damage and remodeling. In this manuscript, we review recent published research on cardiac aging. We summarize the aging heart biology, highlighting key molecular pathways and cellular processes that underlie the redox signaling changes during aging. Main ROS sources, antioxidant defenses, and the role of dysfunctional mitochondria in the aging heart are addressed. As metabolism changes contribute to cardiac aging, we also comment on the most prevalent metabolic alterations. This review will help us to understand the mechanisms involved in the heart aging process and will provide a background for attractive molecular targets to prevent age-driven pathology of the heart. A greater understanding of the processes involved in cardiac aging may facilitate our ability to mitigate the escalating burden of CVD in older individuals and promote healthy cardiac aging.

Development of Mitochondria-Targeted Small-Molecule Dyes for Myocardial PET and Fluorescence Bimodal Imaging

Mitochondria-targeting positron emission tomography (PET) and fluorescent dual-modal probes are rarely reported. As one of the most promising lipophilic cations, F16 and its derivatives (F16s) have never been used for myocardial imaging. In this work, 14 F16s are synthesized and evaluated for cardiac imaging. In vitro cell fluorescence imaging revealed that the lead probe 5MEF is precisely localized in the mitochondria of cardiomyocytes. In addition, it shows excellent ex vivo fluorescence imaging quality with the heart-to-muscle and heart-to-liver ratios up to ∼2. Furthermore, the radiofluorinated probe ¹⁸F-5MEF is successfully prepared and shows a high initial heart uptake of 8.66 ± 0.34 % ID/g at 5 min post injection. It displays a high heart imaging performance, a long retention time in the heart, and a low background in the most normal tissues as revealed by PET. To our knowledge, this is the first time novel F16 analogues are designed and developed for myocardial dual-modal imaging.

An Overview of the Beneficial Role of Antioxidants in the Treatment of Nanoparticle-Induced Toxicities

Nanoparticles (NPs) are used in many products and materials for humans such as electronics, in medicine for drug delivery, as biosensors, in biotechnology, and in agriculture, as ingredients in cosmetics and food supplements. Besides that, NPs may display potentially hazardous properties on human health and the environment as a consequence of their abundant use in life nowadays. Hence, there is increased interest of researchers to provide possible therapeutic agents or dietary supplements for the amelioration of NP-induced toxicity. This review summarizes the new findings in the research of the use of antioxidants as supplements for the prevention and alleviation of harmful effects caused by exposure of organisms to NPs. Also, mechanisms involved in the formation of NP-induced oxidative stress and protective mechanisms using different antioxidant substances have also been elaborated. This review also highlights the potential of naturally occurring antioxidants for the enhancement of the antioxidant defense systems in the prevention and mitigation of organism damage caused by NP-induced oxidative stress. Based on the presented results of the most recent studies, it may be concluded that the role of antioxidants in the prevention and treatment of nanoparticle-induced toxicity is unimpeachable. This is particularly important in terms of oxidative stress suppression.

Chlorogenic acid protects human chondrocyte C28/I2 cells from oxidative stress-induced cell death through activation of autophagy

AIMS

The development of osteoarthritis (OA), the most common form of arthritis, is commonly associated with oxidative stress. Indeed, the lack of antioxidant responses largely increases OA incidence. OA is a leading cause of disability in the elderly, which reduces the quality of life and places high socioeconomic burdens on them. Several polyphenolic compounds, including chlorogenic acid (CGA), have shown cytoprotective effects via their antioxidant activity, but the exact mechanism (s) remain elusive. In this study, we demonstrated how CGA protects human chondrocytes against H₂O₂-induced apoptosis.

MATERIALS AND METHODS

The cytoprotective effect by CGA in 500 μM hydrogen peroxide-treated C28/I2 cells was evaluated by cell viability, TUNEL assay, and Western blotting analyses, and autophagy assessment was further performed by AO and MDC staining and tandem mRFP-GFP fluorescence analyses.

KEY FINDINGS

Treatment of CGA to the human chondrocytes under oxidative stress significantly decreased apoptosis markers, such as cleaved caspase 3 and cleaved PARP, and increased anti-apoptotic marker Bcl-xL and the antioxidant response proteins NRF2 and NF-κB. Furthermore, CGA-dependent activation of antioxidant response proteins NRF2 and NF-κB and its protective effects in chondrocytes depended on autophagy. Indeed, CGA treatment and autophagy induction significantly decreased reactive oxygen species (ROS)-induced apoptosis.

SIGNIFICANCE

CGA exhibited the protective effect to human chondrocyte C28/I2 cells against oxidative stress-induced cell death by activating autophagy. These findings indicate that CGA is a potential therapeutic agent for the development of OA drugs.

An Overview of the Beneficial Role of Antioxidants in the Treatment of Nanoparticle-Induced Toxicities

Nanoparticles (NPs) are used in many products and materials for humans such as electronics, in medicine for drug delivery, as biosensors, in biotechnology, and in agriculture, as ingredients in cosmetics and food supplements. Besides that, NPs may display potentially hazardous properties on human health and the environment as a consequence of their abundant use in life nowadays. Hence, there is increased interest of researchers to provide possible therapeutic agents or dietary supplements for the amelioration of NP-induced toxicity. This review summarizes the new findings in the research of the use of antioxidants as supplements for the prevention and alleviation of harmful effects caused by exposure of organisms to NPs. Also, mechanisms involved in the formation of NP-induced oxidative stress and protective mechanisms using different antioxidant substances have also been elaborated. This review also highlights the potential of naturally occurring antioxidants for the enhancement of the antioxidant defense systems in the prevention and mitigation of organism damage caused by NP-induced oxidative stress. Based on the presented results of the most recent studies, it may be concluded that the role of antioxidants in the prevention and treatment of nanoparticle-induced toxicity is unimpeachable. This is particularly important in terms of oxidative stress suppression.

Mitochondrial Dysfunction in Cardiorenal Syndrome 3: Renocardiac Effect of Vitamin C

Cardiorenal syndrome (CRS) is a pathological link between the kidneys and heart, in which an insult in a kidney or heart leads the other organ to incur damage. CRS is classified into five subtypes, and type 3 (CRS3) is characterized by acute kidney injury as a precursor to subsequent cardiovascular changes. Mitochondrial dysfunction and oxidative and nitrosative stress have been reported in the pathophysiology of CRS3. It is known that vitamin C, an antioxidant, has proven protective capacity for cardiac, renal, and vascular endothelial tissues. Therefore, the present study aimed to assess whether vitamin C provides protection to heart and the kidneys in an in vivo CRS3 model. The unilateral renal ischemia and reperfusion (IR) protocol was performed for 60 min in the left kidney of adult mice, with and without vitamin C treatment, immediately after IR or 15 days after IR. Kidneys and hearts were subsequently collected, and the following analyses were conducted: renal morphometric evaluation, serum urea and creatinine levels, high-resolution respirometry, amperometry technique for NO measurement, gene expression of mitochondrial dynamic markers, and NOS. The analyses showed that the left kidney weight was reduced, urea and creatinine levels were increased, mitochondrial oxygen consumption was reduced, NO levels were elevated, and Mfn2 expression was reduced after 15 days of IR compared to the sham group. Oxygen consumption and NO levels in the heart were also reduced. The treatment with vitamin C preserved the left kidney weight, restored renal function, reduced NO levels, decreased iNOS expression, elevated constitutive NOS isoforms, and improved oxygen consumption. In the heart, oxygen consumption and NO levels were improved after vitamin C treatment, whereas the three NOS isoforms were overexpressed. These data indicate that vitamin C provides protection to the kidneys and some beneficial effects to the heart after IR, indicating it may be a preventive approach against cardiorenal insults.

Antioxidant and Mitochondria-Targeted Activity of Caffeoylquinic-Acid-Rich Fractions of Wormwood (Artemisia absinthium L.) and Silver Wormwood (Artemisia ludoviciana Nutt.)

Caffeoylquinic acids are some of the chemophenetically significant specialized metabolites found in plants of the family Asteraceae Dumort., possessing a broad spectrum of biological activities. As they might be potential mitochondria-targeted antioxidants, effective preparation methods—including extraction, isolation, and purification of caffeoylquinic acids from plant sources—are in great demand. The aim of this study was to fractionate the caffeoylquinic acids from cultivated wormwood (Artemisia absinthium L.) and silver wormwood (Artemisia ludoviciana Nutt.) herb acetone extracts and evaluate their phytochemical profiles, antioxidant activity (radical scavenging and reducing activities), effects on kidney mitochondrial functions, and cytochrome-c-reducing properties. The main findings of our study are as follows: (1) Aqueous fractions purified from wormwood and silver wormwood herb acetone extracts are rich in monocaffeoylquinic acids (chlorogenic acid, neochlorogenic acid, 4-O-caffeoylquinic acid), while methanolic fractions purified from wormwood and silver wormwood herb acetone extracts are rich in dicaffeoylquinic acids (4,5-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid). Aqueous fractions purified from wormwood and silver wormwood herb acetone extracts were solely composed of monocaffeoylquinic acids. Methanolic fractions purified from wormwood and silver wormwood herb acetone extracts contained only dicaffeoylquinic acids. (2) Fractions purified from silver wormwood herb acetone extracts stood out as having the greatest content of caffeoylquinic acids. (3) The greatest radical scavenging activity was determined in the dicaffeoylquinic-acid-rich fraction purified from silver wormwood herb acetone extract; the greatest reducing activity was determined in the dicaffeoylquinic-acid-rich fraction purified from wormwood herb acetone extract. (4) The effect of both fractions on mitochondrial functions was dose-dependent; lower concentrations of caffeoylquinic-acid-rich fractions had no effect on mitochondrial functions, whereas higher concentrations of caffeoylquinic-acid-rich fractions reduced the state 3 respiration rate (with the complex-I-dependent substrate glutamate/malate). (5) Both monocaffeoylquinic- and dicaffeoylquinic-acid-rich fractions possessed cytochrome-c-reducing properties; the greatest cytochrome c reduction properties were determined in the dicaffeoylquinic-acid-rich fraction purified from wormwood herb acetone extract. In summary, these findings show that caffeoylquinic acids might be beneficial as promising antioxidant and cytochrome-c-reducing agents for the modulation of mitochondria and treatment of various mitochondrial-pathway-associated pathologies.