Mitochondrial pathways to cardiac recovery: TFAM

The mitochondrial LONP1 protease: molecular targets and role in pathophysiology

Lon peptidase 1 (LONP1), a member of the AAA + family, is essential for maintaining mitochondrial function. Recent studies have revealed that LONP1 serves as a multifunctional enzyme, acting not only as a protease but also as a molecular chaperone, interacting with mitochondrial DNA (mtDNA), and playing roles in mitochondrial dynamics, oxidative stress, cellular respiration, and energy metabolism. LONP1 is evolutionarily highly conserved, and mutations or dysfunctions in LONP1 can lead to diseases. There is growing evidence linking LONP1 to various human diseases, such as tumors, neurodegenerative diseases, and heart diseases. This review discusses the discovery, molecular structure, subcellular localization, tissue distribution, and mitochondrial function of LONP1. Furthermore, it summarizes the associations between LONP1 and tumors, neurodegenerative diseases, and heart diseases, exploring its role in different diseases and potential molecular mechanisms. It also analyzes the regulatory effects of related inhibitors and agonists on LONP1. Considering the pleiotropic effects of LONP1, the study of LONP1 is crucial to understanding the relevant pathophysiological processes and developing strategies to modulate and control these related diseases.

Physiological and morphological impact of physical activity and nutritional interventions to offset disuse-induced skeletal muscle atrophy

Skeletal muscle tissue acts as a functional unit for physical movements, energy metabolism, thermogenesis, and metabolic homeostasis. In this literature review, the underlying mechanisms of skeletal muscle atrophy and the prevention strategies, including vigorous training and nutritional modifications are focused. Furthermore, the comparative analysis of multiple interventions is briefly explained. Ageing is an inevitable process often associated with cognitive impairment and physical decline due to muscular atrophy. Skeletal muscle atrophy is characterized by low muscle mass due to multiple underlying factors, i.e., genetic predisposition, ageing, inflammation, and trauma. The structural alterations include myofiber shrinkage, changes in myosin isoforms, decrease in myofiber diameter, and total protein loss. Furthermore, there is an imbalance in protein anabolic and catabolic reactions. This may be due to changes in multiple signal transduction pathways of protein degradation (i.e., caspase, calpain, ubiquitin protein degradation system, autophagy) and protein anabolism via the mTOR pathway. Consequently, certain pathophysiological factors associated with health disparities may reduce mobility and functional capacity to perform ADLs. To tackle this issue, novel strategies linked to physical movement, and dietary intake must be incorporated in life. Exercise poses multiple health benefits, including improved muscle mass and mobility. Diet diversification [particularly protein-rich meals] and the "whole food" approach (based on non-protein nutrients) may enhance intramuscular anabolic signaling and tissue remodeling. However, there is a pressing need to fund large-scale evidence-based trials based on modern machine learning techniques (AI-driven nutrition). Additionally, entrepreneurial platforms for commercialization of consumer-friendly food products must be initiated in future.

Comprehensive ubiquitome analysis reveals persistent mitochondrial remodeling disruptions from doxorubicin-induced cardiotoxicity in aged CD-1 male mice

Doxorubicin (DOX)-associated cardiotoxicity is characterized by long-term manifestations, whose mechanisms remain incompletely understood, and is exacerbated by various risk factors, with age being a prominent contributor. The objective of this study was to assess the enduring cardiac molecular impacts of DOX in old CD-1 male mice, focusing on ubiquitinated proteins. At 19 months of age, DOX group received a cumulative dose of 9.0 mg/kg of DOX, while control animals got saline solution. Animals were sacrificed 2 months after the administration. DOX induced heart structural changes and increased proteolytic activity. Additionally, increased protein ubiquitination was observed in DOX group, despite the decreased content of the E3 ubiquitin-protein ligase Atrogin-1. A search of poly-ubiquitinated proteins, enriched by tandem ubiquitin-binding entities (TUBEs), showed increased poly-ubiquitination of proteins associated with sarcomere organization and mitochondrial metabolism processes by DOX. Increased mitochondrial density inferred by higher citrate synthase activity was found in DOX group. Moreover, decreased biogenesis and auto(mito)phagy occurred in DOX animals, proven by decreased peroxisome proliferator-activated receptor γ coactivator 1 α, Beclin1 and microtubule-associated protein light chain 3 content. These findings indicate a reduction in mitochondrial biogenesis and accumulation of dysfunctional mitochondria in the aged heart, along with elevated levels of poly-ubiquitinated proteins after DOX treatment. Thus, the disruption of mitochondrial remodeling and impaired protein ubiquitination emerge as enduring consequences of DOX-induced cardiotoxicity, persisting for even 2 months after DOX exposure. This underscores the long-lasting impact of DOX, with significant effects continuing beyond the period of administration, which advocates for longer clinical surveillance.

Blocking the mineralocorticoid receptor prevents cardiac and mitochondrial dysfunction through the activation of NOX-4 in female hormone deprivation rats

AIM

Young women exhibit lower rates of cardiovascular disease (CVD) than age-matched men, a protective effect often attributed to estrogen's influence on cardiac and mitochondrial function. The risk of CVD increases in post-menopausal women, likely due to estrogen deficiency and aldosterone's negative effects, including those on mitochondria and other cellular targets. This study aimed to explore the link between estrogen deficiency and mitochondrial dysfunction in cardiac health. We hypothesized that in estrogen-deprived conditions, aldosterone could stimulate NADPH oxidase, leading to mitochondrial dysfunction, and reduced cardiac contractility.

METHODS

Wistar rats were divided into four groups: Sham, Ovariectomy-induced hormone deprivation (Ovx), Ovx with apocynin treatment, and Ovx with spironolactone treatment for 60 days.

RESULTS

Both apocynin and spironolactone countered the adverse effects of hormone deprivation by preserving myocardial contractility, improving cellular responses to calcium and isoproterenol, and normalizing the expression of key mitochondrial proteins. These compounds also attenuated the increase in reactive oxygen species (ROS) and maintained mitochondrial respiration rates.

CONCLUSION

We concluded that estrogen deficiency contributes to cardiac oxidative stress via the NADPH oxidase and mitochondrial pathways. Apocynin and spironolactone offer significant protective effects, opening new avenues for treating cardiac issues related to estrogen deficiency.

Recent development of mitochondrial metabolism and dysfunction in osteoarthritis

Osteoarthritis is a degenerative joint disorder characterized by cartilage degradation, synovial inflammation, and altered subchondral bone structure. Recent insights have identified mitochondrial dysfunction as a pivotal factor in OA pathogenesis, contributing to chondrocyte apoptosis, oxidative stress, and extracellular matrix degradation. Disruptions in mitochondrial dynamics, including impaired biogenesis, mitophagy, and metabolic shifts from oxidative phosphorylation to glycolysis, exacerbate cartilage damage by promoting the production of reactive oxygen species and matrix-degrading enzymes such as ADAMTS and MMPs. This review explores the molecular mechanisms underlying mitochondrial dysfunction in OA, emphasizing its role in cartilage homeostasis and inflammation. Furthermore, it highlights emerging therapeutic strategies targeting mitochondrial pathways, including antioxidants, mitophagy enhancers, and metabolic modulators, as potential interventions to mitigate disease progression, which offer promising avenues for advancing personalized and disease-modifying treatments in OA.

Mechanisms of mitochondrial damage-associated molecular patterns associated with inflammatory response in cardiovascular diseases

Cardiovascular diseases (CVDs) continue to be a substantial global healthcare burden despite considerable progress in therapies. The inflammatory response during the progression of CVD has attracted considerable attention. Mitochondria serve as the principal energy source for the heart. In cardiovascular illnesses, mitochondrial homeostasis is disrupted, accompanied by structural and functional impairments. During mitochondrial stress or injury, mitochondrial damage-associated molecular patterns (mtDAMPs), such as mitochondrial DNA, cardiolipin, N-formyl peptide, and adenosine triphosphate, are released to activate pattern recognition receptors and trigger immunological responses. Inflammatory responses mediated by mtDAMPs substantially contribute to the pathophysiology of cardiovascular illnesses. In this review, we discuss the molecular mechanisms by which different mtDAMPs control the inflammatory response, address the pathological consequences of mtDAMPs in inducing or exacerbating the inflammatory response in CVDs, and summarize potential therapeutic targets in relevant experimental studies. Preventing or reducing mtDAMP release may play a role in CVD progression by alleviating the inflammatory response.

Depressed TFAM promotes acetaminophen-induced hepatotoxicity regulated by DDX3X-PGC1α-NRF2 signaling pathway

BACKGROUND

Acetaminophen (APAP)-induced acute liver injury (AILI) is the most prevalent cause of acute liver failure and mitochondrial dysfunction plays a dominant role in the pathogenesis of AILI. Mitochondrial transcription factor A (TFAM) is an important marker for maintaining mitochondrial functional homeostasis, but its functions in AILI are unclear. This study aimed to investigate the function of TFAM and its regulatory molecular mechanism in the progression of AILI.

METHODS

The roles of TFAM and DEAD (Asp-Glu-Ala-Asp) box polypeptide 3 X-linked (DDX3X) in AILI were determined with TFAM overexpression and DDX3X knockdown, respectively.

RESULTS

TFAM expression was suppressed in AILI patients. TFAM overexpression alleviated liver necrosis and mitochondrial dysfunction. Treatment of the AILI mice model with N-acetylcysteine (NAC), a drug used to treat APAP overdose, resulted in significant TFAM activation. In vivo experiments confirmed that TFAM expression was negatively regulated by DDX3X. Mechanistic studies showed that nuclear respiratory factor 2 (NRF-2), a key regulator of TFAM, was selectively activated after DDX3X knockdown via activated peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1α), in vivo and in vitro.

CONCLUSIONS

This study demonstrates that depressed hepatic TFAM plays a key role in the pathogenesis of AILI, which is regulated by the DDX3X-PGC1α-NRF2 signaling pathway.

Different amyloid β42 preparations induce different cell death pathways in the model of SH-SY5Y neuroblastoma cells

Amyloid β42 (Aβ42) plays a decisive role in the pathology of Alzheimer's disease. The Aβ42 peptide can aggregate into various supramolecular structures, with oligomers being the most toxic form. However, different Aβ species that cause different effects have been described. Many cell death pathways can be activated in connection with Aβ action, including apoptosis, necroptosis, pyroptosis, oxidative stress, ferroptosis, alterations in mitophagy, autophagy, and endo/lysosomal functions. In this study, we used a model of differentiated SH-SY5Y cells and applied two different Aβ42 preparations for 2 and 4 days. Although we found no difference in the shape and size of Aβ species prepared by two different methods (NaOH or NH4OH for Aβ solubilization), we observed strong differences in their effects. Treatment of cells with NaOH-Aβ42 mainly resulted in damage of mitochondrial function and increased production of reactive oxygen species, whereas application of NH4OH-Aβ42 induced necroptosis and first steps of apoptosis, but also caused an increase in protective Hsp27. Moreover, the two Aβ42 preparations differed in the mechanism of interaction with the cells, with the effect of NaOH-Aβ42 being dependent on monosialotetrahexosylganglioside (GM1) content, whereas the effect of NH4OH-Aβ42 was independent of GM1. This suggests that, although both preparations were similar in size, minor differences in secondary/tertiary structure are likely to strongly influence the resulting processes. Our work reveals, at least in part, one of the possible causes of the inconsistency in the data observed in different studies on Aβ-toxicity pathways.

Selenoprotein o as a regulator of macrophage metabolism in selenium deficiency-induced lung inflammation

Selenium (Se) deficiency induces an inflammatory response in the lungs, but the underlying mechanisms are unknown. Selenoprotein O (SelO) is the largest selenoprotein in terms of molecular weight, yet its potential biological functions have yet to be characterized. Our study revealed that Se deficiency leads to an imbalance in the expression of pro-inflammatory "M1" macrophages and anti-inflammatory "M2" macrophages in alveolar macrophages (AMs) and interstitial macrophages (IMs) and contributed to the development of lung inflammation. Through the analysis of differentially expressed selenoproteins, we identified SelO as a potential regulator of the imbalance in pulmonary macrophage polarization caused by Se deficiency. In vitro experiments showed that SelO knockdown enhanced the polarization of M1 macrophages while suppressing that of M2 macrophages. In addition, SelO knockdown reprogrammed macrophage metabolism to glycolysis, disrupting oxidative phosphorylation (OXPHOS). Mechanistically, SelO primarily targets mitochondrial transcription factor A (TFAM), which plays a crucial role in the transcription and replication of mitochondrial DNA (mtDNA) and is essential for mitochondrial biogenesis and energy metabolism. The deficiency of SelO affects TFAM, resulting in its uncontrolled degradation, which compromises mitochondrial function and energy metabolism. In summary, the findings presented here offer significant theoretical insights into the physiological functions of SelO.

Developing a soft micropatterned substrate to enhance maturation of human induced pluripotent stem cell-derived cardiomyocytes

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSCCMs) offer numerous advantages as a biological model, yet their inherent immaturity compared to adult cardiomyocytes poses significant limitations. This study addresses hiPSCCM immaturity by introducing a physiologically relevant micropatterned substrate for long-term culture and maturation. An innovative microfabrication methodology combining laser etching and casting creates a micropatterned polydimethylsiloxane (PDMS) substrate with varying stiffness, from 2 to 50 kPa, mimicking healthy and fibrotic cardiac tissue. Platinum electrodes were integrated into the cell culture chamber enable pacing of cells at various frequencies. Subsequently, cells were transferred to the incubator for time-course analysis, ensuring contamination-free conditions. Cell contractility, cytosolic Ca2+ transient, sarcomere orientation, and nucleus aspect ratio were analyzed in a 2D hiPSCCM monolayer up to 90 days post-replating in relation to substrate micropattern dimensions. Culturing hiPSCCMs for three weeks on a micropatterned PDMS substrate (2.5-5 µm deep, 20 µm center-to-center spacing of grooves, 2-5 kPa stiffness) emerges as optimal for cardiomyocyte alignment, contractility, and cytosolic Ca2+ transient. The study provides insights into substrate stiffness effects on hiPSCCM contractility and Ca2+ transient at immature and mature states. Maximum contractility and fastest Ca2+transient kinetics occur in mature hiPSCCMs cultured for two to four weeks, with the optimum at three weeks, on a soft micropatterned PDMS substrate. MS proteomic analysis further revealed that hiPSCCMs cultured on soft micropatterned substrates exhibit advanced maturation, marked by significant upregulation of key structural, electrophysiological, and metabolic proteins. This new substrate offers a promising platform for disease modeling and therapeutic interventions. STATEMENT OF SIGNIFICANCE: Human induced pluripotent stem cell derived cardiomyocytes (hiPSCCMs) have been transformative to disease-in-a-dish modeling, drug discovery and testing, and autologous regeneration for human hearts and their role will continue to expand dramatically. However, one of the major limitations of hiPSCCMs is that without intervention, the cells are immature and represent those in the fetal heart. We developed protocols for the fabrication of the PDMS matrices that includes variations in its stiffness and micropatterning. Growing our hiPSCCMs on matrices of comparable stiffness to a healthy heart (5 kPa) and grooves of 20 μm, generate heart cells typical of the healthy adult human heart.

Enduring metabolic modulation in the cardiac tissue of elderly CD-1 mice two months post mitoxantrone treatment

Mitoxantrone (MTX) is a therapeutic agent used in the treatment of solid tumors and multiple sclerosis, recognized for its cardiotoxicity, with underlying molecular mechanisms not fully disclosed. The cardiotoxicity is influenced by risk factors, including age. Our study intended to assess the molecular effect of MTX on the cardiac muscle of old male CD-1 mice. Mice aged 19 months received a total cumulative dose of 4.5 mg/kg of MTX (MTX group) or saline solution (CTRL group). Two months post treatment, blood was collected, animals sacrificed, and the heart removed. MTX caused structural cardiac changes, which were accompanied by extracellular matrix remodeling, as indicated by the increased ratio between matrix metallopeptidase 2 and metalloproteinase inhibitor 2. At the metabolic level, decreased glycerol levels were found, together with a trend towards increased content of the electron transfer flavoprotein dehydrogenase. In contrast, lower glycolysis, given by the decreased content of glucose transporter GLUT4 and phosphofructokinase, seemed to occur. The findings suggest higher reliance on fatty acids oxidation, despite no major remodeling occurring at the mitochondrial level. Furthermore, the levels of glutamine and other amino acids (although to a lesser extent) were decreased, which aligns with decreased content of the E3 ubiquitin-protein ligase Atrogin-1, suggesting a decrease in proteolysis. As far as we know, this was the first study made in old mice with a clinically relevant dose of MTX, evaluating its long-term cardiac effects. Even two months after MTX exposure, changes in metabolic fingerprint occurred, highlighting enduring cardiac effects that may require clinical vigilance.

Arsenic induced cardiotoxicity: An approach for molecular markers, epigenetic predictors and targets

Arsenic, a ubiquitous environmental toxicant, has been acknowledged as a significant issue for public health due to its widespread pollution of drinking water and food supplies. The present review aimed to study the toxicity associated with the cardiac system. Prolonged exposure to arsenic has been associated with several harmful health outcomes, especially cardiotoxicity. Arsenic-induced cardiotoxicity encompasses a range of cardiovascular abnormalities, including cardiac arrhythmias, ischemic heart disease, and cardiomyopathy. To tackle this toxicity, understanding the molecular markers, epigenetic predictors, and targets involved in arsenic-induced cardiotoxicity is essential for creating preventative and therapeutic approaches. For preventive measures against this heavy metal poisoning of groundwater, it is crucial to regularly monitor water quality, re-evaluate scientific findings, and educate the public about the possible risks. This review thoroughly summarised what is currently known in this field, highlighting the key molecular markers, epigenetic modifications, and potential therapeutic targets associated with arsenic-induced cardiotoxicity.

The role and intervention of mitochondrial metabolism in osteoarthritis

Osteoarthritis (OA), a prevalent degenerative joint disease, affects a substantial global population. Despite the elusive etiology of OA, recent investigations have implicated mitochondrial dysfunction as a significant factor in disease pathogenesis. Mitochondria, pivotal cellular organelles accountable for energy production, exert essential roles in cellular metabolism. Hence, mitochondrial dysfunction can exert broad-ranging effects on various cellular processes implicated in OA development. This comprehensive review aims to provide an overview of the metabolic alterations occurring in OA and elucidate the diverse mechanisms through which mitochondrial dysfunction can contribute to OA pathogenesis. These mechanisms encompass heightened oxidative stress and inflammation, perturbed chondrocyte metabolism, and compromised autophagy. Furthermore, this review will explore potential interventions targeting mitochondrial metabolism as means to impede or decelerate the progression of OA. In summary, this review offers a comprehensive understanding of the involvement of mitochondrial metabolism in OA and underscores prospective intervention strategies.

Release of damaged mitochondrial DNA: A novel factor in stimulating inflammatory response

Mitochondrial DNA (mtDNA) is a circular double-stranded genome that exists independently of the nucleus. In recent years, research on mtDNA has significantly increased, leading to a gradual increase in understanding of its physiological and pathological characteristics. Reactive oxygen species (ROS) and other factors can damage mtDNA. This damaged mtDNA can escape from the mitochondria to the cytoplasm or extracellular space, subsequently activating immune signaling pathways, such as NLR family pyrin domain protein 3 (NLRP3), and triggering inflammatory responses. Numerous studies have demonstrated the involvement of mtDNA damage and leakage in the pathological mechanisms underlying various diseases including infectious diseases, metabolic inflammation, and immune disorders. Consequently, comprehensive investigation of mtDNA can elucidate the pathological mechanisms underlying numerous diseases. The prevention of mtDNA damage and leakage has emerged as a novel approach to disease treatment, and mtDNA has emerged as a promising target for drug development. This article provides a comprehensive review of the mechanisms underlying mtDNA-induced inflammation, its association with various diseases, and the methods used for its detection.

Mitochondrial dysfunction: A promising therapeutic target for liver diseases

The liver is an important metabolic and detoxification organ and hence demands a large amount of energy, which is mainly produced by the mitochondria. Liver tissues of patients with alcohol-related or non-alcohol-related liver diseases contain ultrastructural mitochondrial lesions, mitochondrial DNA damage, disturbed mitochondrial dynamics, and compromised ATP production. Overproduction of mitochondrial reactive oxygen species induces oxidative damage to mitochondrial proteins and mitochondrial DNA, decreases mitochondrial membrane potential, triggers hepatocyte inflammation, and promotes programmed cell death, all of which impair liver function. Mitochondrial DNA may be a potential novel non-invasive biomarker of the risk of progression to liver cirrhosis and hepatocellular carcinoma in patients infected with the hepatitis B virus. We herein present a review of the mechanisms of mitochondrial dysfunction in the development of acute liver injury and chronic liver diseases, such as hepatocellular carcinoma, viral hepatitis, drug-induced liver injury, alcoholic liver disease, and non-alcoholic fatty liver disease. This review also discusses mitochondrion-centric therapies for treating liver diseases.

Exosomes from umbilical cord mesenchymal stem cells ameliorate intervertebral disc degeneration via repairing mitochondrial dysfunction

Background

Reactive oxygen species (ROS), predominantly generated by mitochondria, play a crucial role in the pathogenesis of intervertebral disc degeneration (IVDD). Reduction of ROS levels may be an effective strategy to delay IVDD. In this study, we assessed whether umbilical cord mesenchymal stem cell-exosomes (UCMSC-exos) can be used to treat IVDD by suppressing ROS production caused by mitochondrial dysfunction.

Materials and methods

Human UCMSC-exos were isolated and identified. Nucleus pulposus cells (NPCs) were stimulated with H2O2 in the presence or absence of exosomes. Then, 4D label free quantitative (4D-LFQ) proteomics were used to analyze the differentially expressed (DE) proteins. Mitochondrial membrane potential (MMP), mitochondrial ROS and protein levels were determined via immunofluorescence staining, flow cytometry and western blotting respectively. Additionally, high-throughput sequencing was performed to identify the DE miRNAs in NPCs. Finally, therapeutic effects of UCMSC-exos were investigated in a puncture-induced IVDD rat model. Degenerative grades of rat IVDs were assessed using magnetic resonance imaging and histochemical staining.

Results

UCMSC-exos effectively improved the viability of NPCs and restored the expression of the extracellular matrix (ECM) proteins, collagen type II alpha-1 (COL2A1) and matrix metalloproteinase-13 induced by H2O2. Additionally, UCMSC-exos not only reduced the total intracellular ROS and mitochondrial superoxide levels, but also increased MMP in pathological NPCs. 4D-LFQ proteomics and western blotting further revealed that UCMSC-exos up-regulated the levels of the mitochondrial protein, mitochondrial transcription factor A (TFAM), in H2O2-induced NPCs. High-throughput sequencing and qRT-PCR uncovered that UCMSC-exos down-regulated the levels of miR-194-5p, a potential negative regulator of TFAM, induced by H2O2. Finally, in vivo results showed that UCMSC-exos injection improved the histopathological structure and enhanced the expression levels of COL2A1 and TFAM in the rat IVDD model.

Conclusions

Our findings suggest that UCMSC-exos promote ECM synthesis, relieve mitochondrial oxidative stress, and attenuate mitochondrial dysfunction in vitro and in vivo, thereby effectively treating IVDD.

The translational potential of this article

This study provides solid experimental data support for the therapeutic effects of UCMSC-exos on IVDD, suggesting that UCMSC-exos will be a promising nanotherapy for IVDD.

Tetramethylpyrazine protects mitochondrial function by up-regulation of TFAM and inhibition of neuronal apoptosis in a rat model of surgical brain injury

Objectives

Mitochondrial dysfunction caused by mitochondrial DNA (mtDNA) damage and mutation is widely accepted as one of the pathological processes of neurodegenerative diseases. As an mtDNA binding protein, mitochondrial transcription factor A (TFAM) maintains the integrity of mtDNA through transcription, replication, nucleoid formation, damage perception, and DNA repair. In recent works, the overexpression of TFAM increased the mtDNA copy count, promoted mitochondrial function, and improved the neurological dysfunction of neurodegenerative diseases. The role of TFAM in neurodegenerative diseases has been well explained. However, the role of TFAM after surgical brain injury (SBI) has not been studied. In this work, we aimed to study the role of TFAM in the brain after SBI and its mechanism of action.

Materials and Methods

One hour after the occurrence of SBI, tetramethylpyrazine (TMP) was injected into the abdominal cavity of rats, and the brain was collected 48 hr later for testing. The evaluation included neurobehavioral function test, brain water content measurement, immunofluorescence, western blot, TUNEL staining, FJC staining, ROS test, and ATP test.

Results

After SBI, the content of TFAM on the ipsilateral side increased and reached a peak at about 48 hr. After intraperitoneal injection of TMP in rats, 48 hr after SBI, the concentration of TFAM, Bcl-2, and adenosine triphosphate (ATP) increased; the content of caspase-3, reactive oxygen species (ROS), and cerebral edema decreased; and the nerve function significantly improved.

Conclusion

TMP inhibited cell apoptosis after SBI in rats by up-regulating TFAM and protecting brain tissues.

The Metabolic Fingerprint of Doxorubicin-Induced Cardiotoxicity in Male CD-1 Mice Fades Away with Time While Autophagy Increases

The cardiotoxicity of doxorubicin (DOX) may manifest at the beginning/during treatment or years after, compromising patients' quality of life. We intended to study the cardiac pathways one week (short-term, control 1 [CTRL1] and DOX1 groups) or five months (long-term, CTRL2 and DOX2 groups) after DOX administration in adult male CD-1 mice. Control groups were given saline, and DOX groups received a 9.0 mg/Kg cumulative dose. In the short-term, DOX decreased the content of AMP-activated protein kinase (AMPK) while the electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) increased compared to CTRL1, suggesting the upregulation of fatty acids oxidation. Moreover, mitofusin1 (Mfn1) content was decreased in DOX1, highlighting decreased mitochondrial fusion. In addition, increased B-cell lymphoma-2 associated X-protein (BAX) content in DOX1 pointed to the upregulation of apoptosis. Conversely, in the long-term, DOX decreased the citrate synthase (CS) activity and the content of Beclin1 and autophagy protein 5 (ATG5) compared to CTRL2, suggesting decreased mitochondrial density and autophagy. Our study demonstrates that molecular mechanisms elicited by DOX are modulated at different extents over time, supporting the differences on clinic cardiotoxic manifestations with time. Moreover, even five months after DOX administration, meaningful heart molecular changes occurred, reinforcing the need for the continuous cardiac monitoring of patients and determination of earlier biomarkers before clinical cardiotoxicity is set.

Adenosine, lidocaine and Mg2+ update: teaching old drugs new tricks

If a trauma (or infection) exceeds the body's evolutionary design limits, a stress response is activated to quickly restore homeostasis. However, when the injury severity score is high, death is often imminent. The goal of this review is to provide an update on the effect of small-volume adenosine, lidocaine and Mg2+ (ALM) therapy on increasing survival and blunting secondary injury after non-compressible hemorrhagic shock and other trauma and infective/endotoxemic states. Two standout features of ALM therapy are: (1) resuscitation occurs at permissive hypotensive blood pressures (MAPs 50-60 mmHg), and (2) the drug confers neuroprotection at these low pressures. The therapy appears to reset the body's baroreflex to produce a high-flow, hypotensive, vasodilatory state with maintained tissue O2 delivery. Whole body ALM protection appears to be afforded by NO synthesis-dependent pathways and shifting central nervous system (CNS) control from sympathetic to parasympathetic dominance, resulting in improved cardiovascular function, reduced immune activation and inflammation, correction of coagulopathy, restoration of endothelial glycocalyx, and reduced energy demand and mitochondrial oxidative stress. Recently, independent studies have shown ALM may also be useful for stroke, muscle trauma, and as an adjunct to Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA). Ongoing studies have further shown ALM may have utility for burn polytrauma, damage control surgery and orthopedic surgery. Lastly, we discuss the clinical applications of ALM fluid therapy for prehospital and military far-forward use for non-compressible hemorrhage and traumatic brain injury (TBI).

Research progress of extracellular vesicles and exosomes derived from mesenchymal stem cells in the treatment of oxidative stress-related diseases

There is growing evidence that mesenchymal stem cell-derived extracellular vesicles and exosomes can significantly improve the curative effect of oxidative stress-related diseases. Mesenchymal stem cell extracellular vesicles and exosomes (MSC-EVs and MSC-Exos) are rich in bioactive molecules and have many biological regulatory functions. In this review, we describe how MSC-EVs and MSC-Exos reduce the related markers of oxidative stress and inflammation in various systemic diseases, and the molecular mechanism of MSC-EVs and MSC-Exos in treating apoptosis and vascular injury induced by oxidative stress. The results of a large number of experimental studies have shown that both local and systemic administration can effectively inhibit the oxidative stress response in diseases and promote the survival and regeneration of damaged parenchymal cells. The mRNA and miRNAs in MSC-EVs and MSC-Exos are the most important bioactive molecules in disease treatment, which can inhibit the apoptosis, necrosis and oxidative stress of lung, heart, kidney, liver, bone, skin and other cells, and promote their survive and regenerate.

Protective effect and mechanism research of Phyllanthus emblica Linn. fruit extract on UV-induced photodamage in keratinocytes

Ultraviolet (UV) irradiation causes acute and chronic cutaneous effects that may result in photodamage and photoaging. Epidermis keratinocytes, as the closest surface of skin, are susceptible to damage from UV rays. Phyllanthus emblica Linn. fruit (PE) extract, as a medicine and food dual-use plant, contains high levels of polyphenols and possesses multiple pharmacological properties. The present study investigated common and different molecular mechanisms and signaling pathway activations of UVA and UVB stimulated cell damage and photoprotective effect of PE extract against UVA and UVB by Methyl Thiazolyl Tetrazolium (MTT) method, Elisa assay, flow cytometry, differentially expressed genes analysis and western blot analysis. The results showed that UVA exposure (10 J/cm2) reduced HaCaT cell viability significantly, increased the apoptosis rate, elevated intracellular reactive oxygen species level and reduced antioxidant enzyme activities. And UVA irradiation could inhibit the ERK/TGF-β/Smad signaling pathway to downregulate collagen I, collagen III and elastin expressions, resulting in the photoaging of skin cells. We also found UVB exposure (30 mJ/cm2) caused HaCaT cell damage, promoted apoptosis, increased ROS production and induced the release of proinflammatory cytokines (IL-1α, IL-6 and PGE2). Further, in HaCaT cells, UVB ray was able to induce the activation of apoptosis markers (cleaved PARP1 and cleaved caspase3) through the MAPK/AP-1 signaling pathway using western blot analysis. Pre-treatment of PE extract prevented the UVA and UVB induced photoaging and injury in HaCaT cells through activation of ERK/TGF-β/Smad pathway and inhibition of MAPK/AP-1 pathway, respectively. Therefore, PE extract has the potential to be used as an oral and topical preparation against skin aging and injury induced by UVA and UVB.

Mitochondrial Dysfunction Associated with mtDNA in Metabolic Syndrome and Obesity

Metabolic syndrome (MetS) is a precursor to the major health diseases associated with high mortality in industrialized countries: cardiovascular disease and diabetes. An important component of the pathogenesis of the metabolic syndrome is mitochondrial dysfunction, which is associated with tissue hypoxia, disruption of mitochondrial integrity, increased production of reactive oxygen species, and a decrease in ATP, leading to a chronic inflammatory state that affects tissues and organ systems. The mitochondrial AAA + protease Lon (Lonp1) has a broad spectrum of activities. In addition to its classical function (degradation of misfolded or damaged proteins), enzymatic activity (proteolysis, chaperone activity, mitochondrial DNA (mtDNA)binding) has been demonstrated. At the same time, the spectrum of Lonp1 activity extends to the regulation of cellular processes inside mitochondria, as well as outside mitochondria (nuclear localization). This mitochondrial protease with enzymatic activity may be a promising molecular target for the development of targeted therapy for MetS and its components. The aim of this review is to elucidate the role of mtDNA in the pathogenesis of metabolic syndrome and its components as a key component of mitochondrial dysfunction and to describe the promising and little-studied AAA + LonP1 protease as a potential target in metabolic disorders.

Neocryptotanshinone ameliorates insufficient energy production in heart failure by targeting retinoid X receptor alpha

Retinoid X receptor alpha (RXRα) is a nuclear transcription factor that extensively regulates energy metabolism in cardiovascular diseases. Identification of targeted RXRα drugs for heart failure (HF) therapy is urgently needed. Neocryptotanshinone (NCTS) is a component derived from Salvia miltiorrhiza Bunge, the effect and mechanism of which for treating HF have not been reported. The goal of this study was to explore the pharmacological effects of NCTS on energy metabolism to protect against HF post-acute myocardial infarction (AMI) via RXRα. We established a left anterior descending artery ligation-induced HF post-AMI model in mice and an oxygen-glucose deprivation-reperfusion-induced H9c2 cell model to investigate the cardioprotective effect of NCTS. Component-target binding techniques, surface plasmon resonance (SPR), microscale thermophoresis (MST) and small interfering RNA (siRNA) transfection were applied to explore the potential mechanism by which NCTS targets RXRα. The results showed that NCTS protects the heart against ischaemic damage, evidenced by improvement of cardiac dysfunction and attenuation of cellular hypoxic injury. Importantly, the SPR and MST results showed that NCTS has a high binding affinity for RXRα. Meanwhile, the critical downstream target genes of RXRα/PPARα, which are involved in fatty acid metabolism, including Cd36 and Cpt1a, were upregulated under NCTS treatment. Moreover, NCTS enhanced TFAM levels, promoted mitochondrial biogenesis and increased myocardial adenosine triphosphate levels by activating RXRα. In conclusion, we confirmed that NCTS improves myocardial energy metabolism, including fatty acid oxidation and mitochondrial biogenesis, by regulating the RXRα/PPARα pathway in mice with HF post-AMI.

Cardiac Molecular Remodeling by Anticancer Drugs: Doxorubicin Affects More Metabolism While Mitoxantrone Impacts More Autophagy in Adult CD-1 Male Mice

Doxorubicin (DOX) and mitoxantrone (MTX) are classical chemotherapeutic agents used in cancer that induce similar clinical cardiotoxic effects, although it is not clear if they share similar underlying molecular mechanisms. We aimed to assess the effects of DOX and MTX on the cardiac remodeling, focusing mainly on metabolism and autophagy. Adult male CD-1 mice received pharmacologically relevant cumulative doses of DOX (18 mg/kg) and MTX (6 mg/kg). Both DOX and MTX disturbed cardiac metabolism, decreasing glycolysis, and increasing the dependency on fatty acids (FA) oxidation, namely, through decreased AMP-activated protein kinase (AMPK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) content and decreased free carnitine (C0) and increased acetylcarnitine (C2) concentration. Additionally, DOX heavily influenced glycolysis, oxidative metabolism, and amino acids turnover by exclusively decreasing phosphofructokinase (PFKM) and electron transfer flavoprotein-ubiquinone oxidoreductase (ETFDH) content, and the concentration of several amino acids. Conversely, both drugs downregulated autophagy given by the decreased content of autophagy protein 5 (ATG5) and microtubule-associated protein light chain 3 (LC3B), with MTX having also an impact on Beclin1. These results emphasize that DOX and MTX modulate cardiac remodeling differently, despite their clinical similarities, which is of paramount importance for future treatments.

Targeting Mitochondrial Metabolism to Save the Failing Heart

Despite considerable progress in treating cardiac disorders, the prevalence of heart failure (HF) keeps growing, making it a global medical and economic burden. HF is characterized by profound metabolic remodeling, which mostly occurs in the mitochondria. Although it is well established that the failing heart is energy-deficient, the role of mitochondria in the pathophysiology of HF extends beyond the energetic aspects. Changes in substrate oxidation, tricarboxylic acid cycle and the respiratory chain have emerged as key players in regulating myocardial energy homeostasis, Ca²⁺ handling, oxidative stress and inflammation. This work aims to highlight metabolic alterations in the mitochondria and their far-reaching effects on the pathophysiology of HF. Based on this knowledge, we will also discuss potential metabolic approaches to improve cardiac function.

Platelet-derived extracellular vesicles ameliorate intervertebral disc degeneration by alleviating mitochondrial dysfunction

Mitochondrial dysfunction causes the production of reactive oxygen species (ROS) and oxidative damage, and oxidative stress and inflammation are considered key factors causing intervertebral disc degeneration (IVDD). Thus, restoring the mitochondrial dysfunction is an attractive strategy for treating IVDD. Platelet-derived extracellular vesicles (PEVs) are nanoparticles that target inflammation. Moreover, the vesicles produced by platelets (PLTs) have considerable anti-inflammatory effects. We investigate the use of PEVs as a therapeutic strategy for IVDD in this study. We extract PEVs and evaluate their properties; test their effects on H2O2-induced oxidative damage of nucleus pulposus (NP) cells; verify the role of PEVs in repairing H2O2-induced cellular mitochondrial dysfunction; and demonstrate the therapeutic effects of PEVs in a rat IVDD model. The results confirm that PEVs can restore impaired mitochondrial function, reduce oxidative stress, and restore cell metabolism by regulating the sirtuin 1 (SIRT1)-peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α)-mitochondrial transcription factor A (TFAM) pathway; in rat models, PEVs retard the progression of IVDD. Our results demonstrate that the injection of PEVs can be a promising strategy for treating patients with IVDD.

Identifying Mitochondrial Transcription Factor A As a Potential Biomarker for the Carcinogenesis and Prognosis of Prostate Cancer

Aims: Mitochondrial functional transformation contributes to the carcinogenesis of the prostate by meeting the metabolic needs of cancer cells. Mitochondrial transcription factor A (TFAM) is a pivotal regulator that maintains homeostasis of mitochondrial function. However, its role in prostate carcinogenesis has not been well elucidated. Materials and Methods: In the present study, we analyzed the expression of TFAM in normal prostate tissue and prostate cancer using public databases; a prostate-tissue chip was used to verify the results. The expression of TFAM in normal cells and in prostate cancer cells was determined by western blotting analysis. We knocked down TFAM in the prostate cancer cell line PC3 using a specific shRNA to explore the potential effects of TFAM in prostatic carcinogenesis. Results: We observed higher expression levels of TFAM in prostate cancer tissue than in normal prostate tissue and tumor adjacent normal tissues. A receiver operating characteristic curve was drawn that demonstrated the diagnostic efficacy of using TFAM expression for prostate cancer prognoses. Elevated levels of TFAM may indicate poorer overall survival in prostate cancer patients. Western blotting assays also showed that relative to the normal prostatic epithelial cell line RWPE-1, prostate cancer cell lines PC3 and DU145 expressed more TFAM protein. Furthermore, knockdown of TFAM inhibited the colony-formation capability of PC3 cells. Conclusion: Collectively, these results suggest that TFAM promotes carcinogenesis of the prostate, and may constitute a marker to be used in the diagnosis and prognosis of prostate cancer.

Alteration of Mitochondrial DNA Copy Number and Increased Expression Levels of Mitochondrial Dynamics-Related Genes in Sjögren's Syndrome

Sjögren's syndrome (SS) is a chronic autoimmune multifactorial disease characterized by inflammation and lymphocytic infiltration of the exocrine glands. Several studies have highlighted the involvement of oxidative stress in this pathology, suggesting that it could induce mitochondrial dysfunctions. Mitochondria could have a role in inflammatory and immune processes. Since the mitochondrial DNA (mtDNA) copy number could change in response to physiological or environmental stimuli, this study aimed to evaluate possible alterations in the mtDNA copy number in SS. We have analyzed the amount of mtDNA in the peripheral blood of 74 SS patients and 61 healthy controls by qPCR. Then, since mitochondrial fusion and fission play a crucial role in maintaining the number of mitochondria, we investigated the expression variability of the genes most commonly involved in mitochondrial dynamics in a subgroup of SS patients and healthy controls. Interestingly, we observed a highly significant decrease in mtDNA copies in the SS patients compared to healthy controls (p = 1.44 × 10^-12). Expression levels of mitochondrial fission factor (MFF), mitofusin-1 (MFN1), and mitochondrial transcription factor A (TFAM) genes were analyzed, showing a statistically significant increase in the expression of MFF (p = 0.003) and TFAM (p = 0.022) in the SS patients compared to healthy controls. These results give further insight into the possible involvement of mitochondrial dysfunctions in SS disease.

Immune dysfunction following severe trauma: A systems failure from the central nervous system to mitochondria

When a traumatic injury exceeds the body's internal tolerances, the innate immune and inflammatory systems are rapidly activated, and if not contained early, increase morbidity and mortality. Early deaths after hospital admission are mostly from central nervous system (CNS) trauma, hemorrhage and circulatory collapse (30%), and later deaths from hyperinflammation, immunosuppression, infection, sepsis, acute respiratory distress, and multiple organ failure (20%). The molecular drivers of secondary injury include damage associated molecular patterns (DAMPs), pathogen associated molecular patterns (PAMPs) and other immune-modifying agents that activate the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic stress response. Despite a number of drugs targeting specific anti-inflammatory and immune pathways showing promise in animal models, the majority have failed to translate. Reasons for failure include difficulty to replicate the heterogeneity of humans, poorly designed trials, inappropriate use of specific pathogen-free (SPF) animals, ignoring sex-specific differences, and the flawed practice of single-nodal targeting. Systems interconnectedness is a major overlooked factor. We argue that if the CNS is protected early after major trauma and control of cardiovascular function is maintained, the endothelial-glycocalyx will be protected, sufficient oxygen will be delivered, mitochondrial energetics will be maintained, inflammation will be resolved and immune dysfunction will be minimized. The current challenge is to develop new systems-based drugs that target the CNS coupling of whole-body function.

Protective effects of silver nanoparticles in isoproterenol-induced myocardial infarction in rats

Background

Silver nanoparticles (AgNPs) are widely used in the medical field, including cardiovascular. However, limited research has investigated the effect of AgNPs on the protection of myocardial infarction (MI).

Objectives

Isoproterenol (Iso)-induced MI and the cardiac protection offered by AgNPs were investigated in the present study. Additionally, we characterized the profile of Ag in the form of nanoparticles.

Methods

Twenty-four male Wistar rats were randomly divided into four groups as follows: normal, Iso, Iso + AgNO3, and Iso + AgNP groups. AgNPs and silver ion (AgNO3) were administered intraperitoneally at 2.5 mg/kg BW for 14 days. Iso induction was performed using two doses of 85 mg/kg BW given subcutaneously on days 13 and 14. Blood and cardiac tissue samples were taken 24 h after the last dose of Iso and checked for Creatine Kinase-MB (CK-MB), lactate dehydrogenase in plasma along with oxidative stress parameters, mitochondria biogenesis markers, and inflammation representative genes in cardiac tissue. Additionally, we analyzed the histopathological features in cardiac tissue.

Results

The silver was confirmed in the form of nanoparticles by its size at intervals of 8.72-37.84 nm. Both AgNO3 and AgNPs showed similar cardioprotective effects, as shown by the decrease in biochemical markers of cardiac toxicity, namely, CK-MB. Additionally, AgNPs group have better efficacy compared with AgNO3 group in ameliorating Iso-mediated oxidative stress production, as evidenced by the significant decrease in malondialdehyde level and increased superoxide dismutase activity (P < 0.0001 and P < 0.01, respectively) in cardiac tissue compared with the Iso group. Mechanistically, AgNPs, but not AgNO3, enhanced the expression levels of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-gamma coactivator 1-alpha in post-MI heart and reduced the protein expression of nuclear factor-kappa B (NF-κB) assessed by western blot analysis. Furthermore, these results were confirmed with the histopathological evaluation of cardiac tissue. Nevertheless, pretreatment with either AgNO3 or AgNPs improved the aspartate aminotransferase level.

Conclusion

These results suggested that AgNPs have more superior cardioprotective effect compared with AgNO3 against Iso-induced MI, at least in part through amelioration of NF-κB expression level induced by oxidative stress overproduction.

Transcriptomic Analysis of Dysregulated Genes of the nDNA-mtDNA Axis in a Mouse Model of Dilated Cardiomyopathy

Background: Mitochondrial dysfunction is implicated in the development of cardiomyopathy and heart failure. Transcription of mitochondrial DNA (mtDNA) encoded genes and subsequent protein synthesis are tightly regulated by nuclear DNA (nDNA) encoded proteins forming the nDNA-mtDNA axis. The scale of abnormalities in this axis in dilated cardiomyopathy (DCM) is unclear. We previously demonstrated, in a mouse DCM model with cardiac Mst1 overexpression, extensive downregulation of mitochondrial genes and mitochondrial dysfunction. Using the pre-acquired transcriptome sequencing database, we studied expression of gene sets of the nDNA-mtDNA axis.

Methods: Using RNA-sequencing data from DCM hearts of mice at early and severe disease stages, transcriptome was performed for dysregulated nDNA-encoded gene sets that govern mtDNA transcription and in situ protein synthesis. To validate gene data, expression of a panel of proteins was determined by immunoblotting.

Results: Relative to littermate controls, DCM hearts showed significant downregulation of all mtDNA encoded mRNAs, as well as mtDNA transcriptional activators. Downregulation was also evident for gene sets of mt-rRNA processing, aminoacyl-tRNA synthases, and mitoribosome subunits for in situ protein synthesis. Multiple downregulated genes belong to mitochondrial protein-importing machinery indicating compromised importing of proteins for mtDNA transcription and translation. Diverse changes were genes of mtRNA-binding proteins that govern maturation and stability of mtDNA-derived RNAs. Expression of mtDNA replicome genes was largely unchanged. These changes were similarly observed in mouse hearts at early and severe stages of DCM.

Conclusion: Transcriptome revealed in our DCM model dysregulation of multiple gene sets of the nDNA-mtDNA axis, that is, expected to interfere with mtDNA transcription and in situ protein synthesis. Dysfunction of the nDNA-mtDNA axis might contribute to mitochondrial dysfunction and ultimately development of DCM.

Curcumin Improves Cardiopulmonary Resuscitation Outcomes by Modulating Mitochondrial Metabolism and Apoptosis in a Rat Model of Cardiac Arrest

Background

Curcumin, a diarylheptanoid chemical compound extracted from curcuma longa, exerts a variety of biological and pharmacological effects in numerous pathological conditions, including ischemia/reperfusion (I/R) injury. In this study, we investigated its role in post-resuscitation myocardial dysfunction in a rat model of cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) by targeting on mitochondrial metabolism and apoptosis.

Methods

Animals were randomized into three groups: sham, control and curcumin, with fifteen rats in each group. Ventricular fibrillation (VF) was induced in the rats of the control and curcumin groups. The rats in the two groups were untreated for 8 min, followed by CPR for 8 min. Placebo (saline) or curcumin was administered by intraperitoneal injection, respectively, 5 min after successful resuscitation. Myocardial function was measured at baseline and post-resuscitation for 6 h consecutively. Ten rats in each group were closely observed for an additional 66 h to analyze the survival status, and the remaining five were sacrificed for the measurement of mitochondrial parameters and cell apoptosis.

Results

Compared with the control group, myocardial function was significantly enhanced in the curcumin group, contributing to a better survival status. Curcumin treatment mitigated the depletion of superoxide dismutase (SOD) and the production of malondialdehyde (MDA). The structural damage of mitochondria was also alleviated, with improved conditions of mPTP and ΔΨm. Curcumin boosted the production of ATP and attenuated myocardial apoptosis. Cytochrome C, caspase-3 and its cleavage were suppressed by curcumin. Proteins closely related to the functional performance of mitochondria, including uncoupling protein 2 (UCP2) and uncoupling protein 3 (UCP3) were downregulated, while mitochondrial transcription factor A (mtTFA) was upregulated.

Conclusion

Curcumin improves the outcomes of CPR via alleviating myocardial dysfunction induced by I/R injury. It exhibits anti-oxidation properties. Moreover, it is capable of ameliorating mitochondrial structure and energy metabolism, as well as inhibiting the mitochondrial apoptosis pathway. UCP2, UCP3, and mtTFA might also be involved in curcumin mediated protective effects on mitochondria.

Exploration of Reduced Mitochondrial Content–Associated Gene Signature and Immunocyte Infiltration in Colon Adenocarcinoma by an Integrated Bioinformatic Analysis

Purpose: Mitochondrial dysfunction refers to cancer immune evasion. A novel 7-gene prognostic signature related to the mitochondrial DNA copy number was utilized to evaluate the immunocyte infiltration in colon cancer according to the risk scores and to predict the survival for colon cancer.

Experimental design: We performed an integrated bioinformatic analysis to analyze transcriptome profiling of the EB-treated mitochondrial DNA–defected NCM460 cell line with differentially expressed genes between tumor and normal tissues of COAD in TCGA. The LASSO analysis was utilized to establish a prognostic signature. ESTIMATE and CIBERSORT validated the differences of immunocyte infiltration between colon cancer patients with high- and low-risk scores.

Results: Our study identified a 7-gene prognostic signature (LRRN2, ANKLE1, GPRASP1, PRAME, TCF7L1, RAB6B, and CALB2). Patients with colon cancer were split into the high- and low-risk group by the risk scores in TCGA (training cohort: HR = 2.50 p &lt; 0.0001) and GSE39582 (validation cohort: HR = 1.43 p &lt; 0.05). ESTIMATE and CIBERSORT revealed diverseness of immune infiltration in the two groups, especially downregulated T-cell infiltration in the patients with high-risk scores. Finally, we validated the colon patients with a low expression of the mitochondrial number biomarker TFAM had less CD3+ and CD8+ T-cell infiltration in clinical specimens.

Conclusion: An mtDNA copy number-related 7-gene prognostic signature was investigated and evaluated, which may help to predict the prognosis of colon cancer patients and to guide clinical immunotherapy via immunocyte infiltration evaluation.

ALM Fluid Therapy Shifts Sympathetic Hyperactivity to Parasympathetic Dominance in the Rat Model of Non-Compressible Hemorrhagic Shock

ABSTRACT

Excessive sympathetic outflow following trauma can lead to cardiac dysfunction, inflammation, coagulopathy, and poor outcomes. We previously reported that buprenorphine analgesia decreased survival after hemorrhagic trauma. Our aim is to examine the underlying mechanisms of mortality in a non-compressible hemorrhage rat model resuscitated with saline or adenosine, lidocaine, magnesium (ALM). Anesthetized adult male Sprague-Dawley rats were randomly assigned to Saline control group or ALM therapy group (both n = 10). Hemorrhage was induced by 50% liver resection. After 15 min, 0.7 mL/kg 3% NaCl ± ALM intravenous bolus was administered, and after 60 min, 0.9% NaCl ± ALM was infused for 4 h (0.5 mL/kg/h) with 72 h monitoring. Animals received 6-12-hourly buprenorphine for analgesia. Hemodynamics, heart rate variability, echocardiography, and adiponectin were measured. Cardiac tissue was analyzed for adrenergic/cholinergic receptor expression, inflammation, and histopathology. Four ALM animals and one Saline control survived to 72 h. Mortality was associated with up to 97% decreases in adrenergic (β-1, α-1A) and cholinergic (M2) receptor expression, cardiac inflammation, myocyte Ca2+ loading, and histopathology, indicating heart ischemia/failure. ALM survivors had higher cardiac output and stroke volume, a 30-fold increase in parasympathetic/sympathetic receptor expression ratio, and higher circulating adiponectin compared to Saline controls. Paradoxically, Saline cardiac adiponectin hormone levels were higher than ALM, with no change in receptor expression, indicating intra-cardiac synthesis. Mortality appears to be a "systems failure" associated with CNS dysregulation of cardiac function. Survival involves an increased parasympathetic dominance to support cardiac pump function with reduced myocardial inflammation. Increased cardiac α-1A adrenergic receptor in ALM survivors may be significant, as this receptor is highly protective during heart dysfunction/failure.

mtDNA in the Pathogenesis of Cardiovascular Diseases

The incidence rate of cardiovascular disease (CVD) has been increasing year by year and has become the main cause for the increase of mortality. Mitochondrial DNA (mtDNA) plays a crucial role in the pathogenesis of CVD, especially in heart failure and ischemic heart diseases. With the deepening of research, more and more evidence showed that mtDNA is related to the occurrence and development of CVD. Current studies mainly focus on how mtDNA copy number, an indirect biomarker of mitochondrial function, contributes to CVD and its underlying mechanisms including mtDNA autophagy, the effect of mtDNA on cardiac inflammation, and related metabolic functions. However, no relevant studies have been conducted yet. In this paper, we combed the current research status of the mechanism related to the influence of mtDNA on the occurrence, development, and prognosis of CVD, so as to find whether these mechanisms have something in common, or is there a correlation between each mechanism for the development of CVD?

Concentrated extract of Prunus mume fruit exerts dual effects in 3T3-L1 adipocytes by inhibiting adipogenesis and inducing beiging/browning

Background

The fruit Prunus mume has beneficial effects in the treatment of obesity and metabolic syndrome. However, its mechanism of action is unclear.

Objective

We assessed the effect of a concentrated water extract of P. mume fruit (CEPM) on adipogenesis and beiging/browning in 3T3-L1 cells.

Methods

The cell viability was determined by MTT assay. Lipid accumulation was assessed with Oil Red O (ORO) staining under different concentrations of CEPM. The effects of CEPM treatment during differentiation on beiging/browning and mitochondrial biogenesis in 3T3-L1 cells were investigated.

Results

CEPM treatment suppressed differentiation and decreased lipid accumulation by downregulating the expression of key adipogenic genes, including PPARγ, C/EBPα, SREBP-1c, FAS, and perilipin A. In contrast, CEPM treatment increased the mitochondrial DNA (mtDNA) content and mRNA levels of mitochondrial biogenesis genes, including NAMPT, Nrf1, Nrf2, and CPT1α, and reduced reactive oxygen species levels. Importantly, CEPM increased the expression of brown/beige hallmark genes (Pgc-1α, Ucp1, Cidea, Cox7α1, Cox8b, Cd137, and Pdk-4), as well as proteins (UCP1, PGC-1α, NRF1, TBX1, and CPT1α). The high-performance liquid chromatography (HPLC) analysis reveals that CEPM contains mumefural, naringin, 5-HMF, citric acid, caffeic acid, and hesperidin.

Conclusion

The first evidence we provided showed that CEPM has a dual role in 3T3-L1 cells inhibiting adipogenesis and promoting beiging/browning, and hence, could be a potential agent in the fight against obesity.

Target Sestrin2 to Rescue the Damaged Organ: Mechanistic Insight into Its Function

Sestrin2 is a stress-inducible metabolic regulator and a conserved antioxidant protein which has been implicated in the pathogenesis of several diseases. Sestrin2 can protect against atherosclerosis, heart failure, hypertension, myocardial infarction, stroke, spinal cord injury neurodegeneration, nonalcoholic fatty liver disease (NAFLD), liver fibrosis, acute kidney injury (AKI), chronic kidney disease (CKD), and pulmonary inflammation. Oxidative stress and cellular damage signals can alter the expression of Sestrin2 to compensate for organ damage. Different stress signals such as those mediated by P53, Nrf2/ARE, HIF-1α, NF-κB, JNK/c-Jun, and TGF-β/Smad signaling pathways can induce Sestrin2 expression. Subsequently, Sestrin2 activates Nrf2 and AMPK. Furthermore, Sestrin2 is a major negative regulator of mTORC1. Sestrin2 indirectly regulates the expression of several genes and reprograms intracellular signaling pathways to attenuate oxidative stress and modulate a large number of cellular events such as protein synthesis, cell energy homeostasis, mitochondrial biogenesis, autophagy, mitophagy, endoplasmic reticulum (ER) stress, apoptosis, fibrogenesis, and lipogenesis. Sestrin2 vigorously enhances M2 macrophage polarization, attenuates inflammation, and prevents cell death. These alterations in molecular and cellular levels improve the clinical presentation of several diseases. This review will shed light on the beneficial effects of Sestrin2 on several diseases with an emphasis on underlying pathophysiological effects.

Mitochondrial TFAM as a Signaling Regulator between Cellular Organelles: A Perspective on Metabolic Diseases

Tissues actively involved in energy metabolism are more likely to face metabolic challenges from bioenergetic substrates and are susceptible to mitochondrial dysfunction, leading to metabolic diseases. The mitochondria receive signals regarding the metabolic states in cells and transmit them to the nucleus or endoplasmic reticulum (ER) using calcium (Ca2+) for appropriate responses. Overflux of Ca2+ in the mitochondria or dysregulation of the signaling to the nucleus and ER could increase the incidence of metabolic diseases including insulin resistance and type 2 diabetes mellitus. Mitochondrial transcription factor A (Tfam) may regulate Ca2+ flux via changing the mitochondrial membrane potential and signals to other organelles such as the nucleus and ER. Since Tfam is involved in metabolic function in the mitochondria, here, we discuss the contribution of Tfam in coordinating mitochondria-ER activities for Ca2+ flux and describe the mechanisms by which Tfam affects mitochondrial Ca2+ flux in response to metabolic challenges.

Major surgery leads to a proinflammatory phenotype: Differential gene expression following a laparotomy

BACKGROUND

The trauma of surgery is a neglected area of research. Our aim was to examine the differential expression of genes of stress, metabolism and inflammation in the major organs of a rat following a laparotomy.

MATERIALS AND METHODS

Anaesthetised Sprague-Dawley rats were randomised into baseline, 6-hr and 3-day groups (n = 6 each), catheterised and laparotomy performed. Animals were sacrificed at each timepoint and tissues collected for gene and protein analysis. Blood stress hormones, cytokines, endothelial injury markers and coagulation were measured.

RESULTS

Stress hormone corticosterone significantly increased and was accompanied by significant increases in inflammatory cytokines, endothelial markers, increased neutrophils (6-hr), higher lactate (3-days), and coagulopathy. In brain, there were significant increases in M1 muscarinic (31-fold) and α-1A-adrenergic (39-fold) receptor expression. Cortical expression of metabolic genes increased ∼3-fold, and IL-1β by 6-fold at 3-days. Cardiac β-1-adrenergic receptor expression increased up to 8.4-fold, and M2 and M1 muscarinic receptors by 2 to 4-fold (6-hr). At 3-days, cardiac mitochondrial gene expression (Tfam, Mtco3) and inflammation (IL-1α, IL-4, IL-6, MIP-1α, MCP-1) were significantly elevated. Haemodynamics remained stable. In liver, there was a dramatic suppression of adrenergic and muscarinic receptor expression (up to 90%) and increased inflammation. Gut also underwent autonomic suppression with 140-fold increase in IL-1β expression (3-days).

CONCLUSIONS

A single laparotomy led to a surgical-induced proinflammatory phenotype involving neuroendocrine stress, cortical excitability, immune activation, metabolic changes and coagulopathy. The pervasive nature of systemic and tissue inflammation was noteworthy. There is an urgent need for new therapies to prevent hyper-inflammation and restore homeostasis following major surgery.

Resveratrol sustains intestinal barrier integrity, improves antioxidant capacity, and alleviates inflammation in the jejunum of ducks exposed to acute heat stress

Resveratrol, a natural antioxidant, anti-inflammatory plant extract, was found to have a protective effect in poultry subjected to heat stress. In this study, we strove to characterize resveratrol on intestinal of duck exposed to acute heat stress and investigate the underlying mechanism. A total of 120 Shan-ma ducks (60 days old) were randomly divided into 2 groups. The control group was fed a basal diet, and the resveratrol group was fed a basal diet supplemented with 400 mg/kg resveratrol. Animals in 2 groups were kept at a temperature of 24°C ± 2°C for 15 d. Then, animals of both groups were placed in an artificial climate room at 39°C. Twelve ducks of each group were sacrificed for sampling at 0, 30, and 60 min, respectively. Results indicated that resveratrol increased the ratio of villus height to crypt depth, increased the number of goblet cells, and reduced the histopathological damage of jejunum caused by acute heat stress. Furthermore, the gene expression of heat shock proteins (HSP60, HSP70, and HSP90) and tight junction proteins (CLDN1 and OCLN) was significantly increased in the resveratrol group compared to that in the control groups. Simultaneously, resveratrol significantly activated the SIRT1-NRF1/NRF2 signaling pathways, improved ATP level of jejunum, and increased SOD and CAT antioxidant enzymes activities. In addition, we found that the NF-κB/NLRP3 inflammasome signaling pathways were repressed under acute heat stress. Meanwhile, supplement resveratrol further inhibited the NLRP3 inflammasome pathway, decreased protein level of NLRP3 and caspase1 p20, reduced the secretion of IL-1β. Taken together, our results indicate that resveratrol against the oxidative damage and inflammation injury in duck jejunum induced by heat stress via active SIRT1 signaling pathways.

Activation of Hippo signaling pathway mediates mitochondria dysfunction and dilated cardiomyopathy in mice

Rationale: Mitochondrial dysfunction facilitates heart failure development forming a therapeutic target, but the mechanism involved remains unclear. We studied whether the Hippo signaling pathway mediates mitochondrial abnormalities that results in onset of dilated cardiomyopathy (DCM). Methods: Mice with DCM due to overexpression of Hippo pathway kinase Mst1 were studied. DCM phenotype was evident in adult animals but contractile dysfunction was identified as an early sign of DCM at 3 weeks postnatal. Electron microscopy, multi-omics and biochemical assays were employed. Results: In 3-week and adult DCM mouse hearts, cardiomyocyte mitochondria exhibited overt structural abnormalities, smaller size and greater number. RNA sequencing revealed comprehensive suppression of nuclear-DNA (nDNA) encoded gene-sets involved in mitochondria turnover and all aspects of metabolism. Changes in cardiotranscriptome were confirmed by lower protein levels of multiple mitochondrial proteins in DCM heart of both ages. Mitochondrial DNA-encoded genes were also downregulated; due apparently to repression of nDNA-encoded transcriptional factors. Lipidomics identified remodeling in cardiolipin acyl-chains, increased acylcarnitine content but lower coenzyme Q10 level. Mitochondrial dysfunction was featured by lower ATP content and elevated levels of lactate, branched-chain amino acids and reactive oxidative species. Mechanistically, inhibitory YAP-phosphorylation was enhanced, which was associated with attenuated binding of transcription factor TEAD1. Numerous suppressed mitochondrial genes were identified as YAP-targets. Conclusion: Hippo signaling activation mediates mitochondrial damage by repressing mitochondrial genes, which causally promotes the development of DCM. The Hippo pathway therefore represents a therapeutic target against mitochondrial dysfunction in cardiomyopathy.

NUPR1: A Critical Regulator of the Antioxidant System

Simple Summary

Nuclear protein 1 (NUPR1) is activated in cellular stress and is expressed at high levels in cancer cells. Much evidence has been gathered supporting its critical role in regulating the antioxidant system. Our review aims to summarize the literature data on the impact of NUPR1 on the oxidative stress response via such a regulatory role and how its inhibition induces reactive oxygen species-mediated cell death, such as ferroptosis.

Abstract

Nuclear protein 1 (NUPR1) is a small intrinsically disordered protein (IDP) activated in response to various types of cellular stress, including endoplasmic reticulum (ER) stress and oxidative stress. Reactive oxygen species (ROS) are mainly produced during mitochondrial oxidative metabolism, and directly impact redox homeostasis and oxidative stress. Ferroptosis is a ROS-dependent programmed cell death driven by an iron-mediated redox reaction. Substantial evidence supports a maintenance role of the stress-inducible protein NUPR1 on cancer cell metabolism that confers chemotherapeutic resistance by upregulating mitochondrial function-associated genes and various antioxidant genes in cancer cells. NUPR1, identified as an antagonist of ferroptosis, plays an important role in redox reactions. This review summarizes the current knowledge on the mechanism behind the observed impact of NUPR1 on mitochondrial function, energy metabolism, iron metabolism, and the antioxidant system. The therapeutic potential of genetic or pharmacological inhibition of NUPR1 in cancer is also discussed. Understanding the role of NUPR1 in the antioxidant system and the mechanisms behind its regulation of ferroptosis may promote the development of more efficacious strategies for cancer therapy.

Matricaria chamomilla (Chamomile) Ameliorates Muscle Atrophy in Mice by Targeting Protein Catalytic Pathways, Myogenesis, and Mitochondrial Dysfunction

Muscle atrophy, or loss of skeletal muscle, is caused by aging, malnutrition, immobility through injury, or diseases such as cancer. Chamomile (Matricaria chamomilla L.) contains various active components, including flavonoids, sesquiterpenes, polyacetylenes, and coumarins, and is used in various herbal medicines in the European Pharmacopoeia. In this study, we investigated the effects of ethanol extract of chamomile [Formula: see text](MC) on muscle wasting and its mechanism of action. Mice with dexamethasone (DEX)-induced muscle atrophy were orally administered MC (100, 200, and 300 mg/kg) for 4 weeks. Micro-computed tomography analysis showed that MC (200 and 300 mg/kg) significantly recovered DEX-induced loss of muscle volume, density, and weight and MC-treated DEX-induced mice also showed increased moving distance and grip strength. MC suppressed the mRNA level of muscle RING finger 1 (MuRF1) while increasing the expression of mitochondrial transcription factor A (TFAM), MyoD, and Myogenin-1. We found 25 peaks in MC samples through HPLC analysis and identified 6 peaks by comparison with a profile of standard compounds: chlorogenic acid (CGA), luteolin-7-O-glucoside (L7G), patulitrin, apigenin-7-O-glucoside (A7G), herniarin, and (E)-tonghaosu. Of these components, the gene expression of MyoD was significantly augmented by patulitrin, herniarin, CGA, and L7G in C2C12 cells, while Myogenin-1 gene expression was increased by A7G, patulitrin, herniarin, CGA, and L7G. Moreover, TFAM gene expression and phosphorylation of AKT were increased by all six ingredients. Based on our results, we suggest MC for use as a supplement or remedy for muscle wasting, including cachexia and sarcopenia.

Critical requirement of SOS1 RAS-GEF function for mitochondrial dynamics, metabolism, and redox homeostasis

SOS1 ablation causes specific defective phenotypes in MEFs including increased levels of intracellular ROS. We showed that the mitochondria-targeted antioxidant MitoTEMPO restores normal endogenous ROS levels, suggesting predominant involvement of mitochondria in generation of this defective SOS1-dependent phenotype. The absence of SOS1 caused specific alterations of mitochondrial shape, mass, and dynamics accompanied by higher percentage of dysfunctional mitochondria and lower rates of electron transport in comparison to WT or SOS2-KO counterparts. SOS1-deficient MEFs also exhibited specific alterations of respiratory complexes and their assembly into mitochondrial supercomplexes and consistently reduced rates of respiration, glycolysis, and ATP production, together with distinctive patterns of substrate preference for oxidative energy metabolism and dependence on glucose for survival. RASless cells showed defective respiratory/metabolic phenotypes reminiscent of those of SOS1-deficient MEFs, suggesting that the mitochondrial defects of these cells are mechanistically linked to the absence of SOS1-GEF activity on cellular RAS targets. Our observations provide a direct mechanistic link between SOS1 and control of cellular oxidative stress and suggest that SOS1-mediated RAS activation is required for correct mitochondrial dynamics and function.

The mitochondrial biogenesis signaling pathway is a potential therapeutic target for myasthenia gravis via energy metabolism (Review)

Myasthenia gravis (MG) is an autoantibody-mediated autoimmune disease that is characterized by muscle weakness and fatigue. Traditional treatments for MG target the neuromuscular junction (NMJ) or the immune system. However, the efficacy of such treatments is limited, and novel therapeutic options for MG are urgently required. In the current review, a new therapeutic strategy is proposed based on the mitochondrial biogenesis and energy metabolism pathway, as stimulating mitochondrial biogenesis and the energy metabolism might alleviate myasthenia gravis. A number of cellular sensors of the energy metabolism were investigated, including AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1). AMPK and SIRT1 are sensors that regulate cellular energy homeostasis and maintain energy metabolism by balancing anabolism and catabolism. Peroxisome proliferator-activated receptor γ coactivator 1α and its downstream transcription factors nuclear respiratory factors 1, nuclear respiratory factors 2, and transcription factor A are key sensors of mitochondrial biogenesis, which can restore mitochondrial DNA and produce new mitochondria. These processes help to control muscle contraction and relieve the symptoms of MG, including muscle weakness caused by dysfunctional NMJ transmission. Therefore, the present review provides evidence for the therapeutic potential of targeting mitochondrial biogenesis for the treatment of MG.

Dihydromyricetin improves mitochondrial outcomes in the liver of alcohol-fed mice via the AMPK/Sirt-1/PGC-1α signaling axis

Alcoholic liver disease (ALD), due to the multifactorial damage associated with alcohol (ethanol) consumption and metabolism, is one of the most prevalent liver diseases in the United States. The liver is the primary site of ethanol metabolism and is subsequently injured due to the production of reactive oxygen species (ROS), acetaldehyde, and metabolic stress. Building evidence suggests that dihydromyricetin (DHM), a bioactive flavonoid isolated from Hovenia dulcis, provides hepatoprotection by enhancing ethanol metabolism in the liver by maintaining hepatocellular bioenergetics, reductions of oxidative stress, and activating lipid oxidation pathways. The present study investigates the utility of DHM on hepatic mitochondrial biogenesis via activation of the AMP-activated protein kinase (AMPK)/Sirtuin (Sirt)-1/PPARG coactivator 1 (PGC)-1α signaling pathway. We utilized a forced drinking ad libitum study that chronically fed 30% ethanol to male C57BL/6J mice over 8 weeks and induced ALD pathology. We found that chronic ethanol feeding resulted in the suppression of AMPK activation and cytoplasmic Sirt-1 and mitochondrial Sirt-3 expression, effects that were reversed with daily DHM administration (5 mg/kg; intraperitoneally [i.p.]). Chronic ethanol feeding also resulted in hepatic hyperacetylation of PGC-1α, which was improved with DHM administration and its mediated increase of Sirt-1 activity. Furthermore, ethanol-fed mice were found to have increased expression of mitochondrial transcription factor A (TFAM), reduced mitochondrial content as assessed by mitochondrial DNA to nuclear DNA ratios, and significantly lower levels of hepatic ATP. In contrast, DHM administration significantly increased TFAM expression, hepatic ATP concentrations, and induced mitochondrial expression of respiratory complex III and V. In total, this work demonstrates a novel mechanism of DHM that improves hepatic bioenergetics, metabolic signaling, and mitochondrial viability, thus adding to the evidence supporting the use of DHM for treatment of ALD and other metabolic disorders.

Transcription of MRPL12 regulated by Nrf2 contributes to the mitochondrial dysfunction in diabetic kidney disease

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Increasing evidences suggested that DKD correlates more closely to mitochondrial dysfunction than to hyperglycemia. Our previous study has reported that mitochondrial ribosomal protein L7/L12 (MRPL12) could positively control the mitochondrial oxidative phosphorylation (OXPHOS) and mtDNA copy number. The present study further investigated the role of MRPL12 in mitochondrial dysfunction of DKD. Using a mass spectrometry-based proteomics and immunohistochemistry, we found that MRPL12 underwent significant decreases in diabetic kidneys. Moreover, decreased expression of MRPL12 was associated with reduced mitochondrial OXPHOS in proximal tubular epithelial cells (PTECs) and overexpression of MRPL12 could alleviated the impairment of OXPHOS induced by long term high glucose. We further explored the upstream mechanism and identified nuclear factor erythroid 2-related factor 2 (Nrf2) as a potential transcription factor for MRPL12. Nrf2 changes consistently with MRPL12 in DKD and correlates with alterations of mitochondrial function, fibrosis and apoptosis of PTECs treated with high glucose challenge. Thus, the role of MRPL12 in the maintenance of mitochondrial function in DKD may be regulated by Nrf2, and provides new potential therapeutic targets for DKD.

Mesenchymal Stem Cell-Derived Extracellular Vesicles Attenuate Mitochondrial Damage and Inflammation by Stabilizing Mitochondrial DNA

Mitochondrial dysfunction is a key feature of injury to numerous tissues and stem cell aging. Although the tissue regenerative role of mesenchymal stem cell (MSC)-derived extracellular vesicles (MSC-EVs) is well known, their specific role in regulating mitochondrial function in target cells remains elusive. Here, we report that MSC-EVs attenuated mtDNA damage and inflammation after acute kidney injury (AKI) and that this effect was at least partially dependent on the mitochondrial transcription factor A (TFAM) pathway. In detail, TFAM and mtDNA were depleted by oxidative stress in MSCs from aged or diabetic donors. Higher levels of TFAM mRNA and mtDNA were detected in normal control (NC) MSC-EVs than in TFAM-knockdown (TFAM-KD) and aged EVs. EV-mediated TFAM mRNA transfer in recipient cells was unaffected by transcriptional inhibition. Accordingly, the application of MSC-EVs restored TFAM protein and TFAM-mtDNA complex (nucleoid) stability, thereby reversing mtDNA deletion and mitochondrial oxidative phosphorylation (OXPHOS) defects in injured renal tubular cells. Loss of TFAM also led to downregulation of multiple anti-inflammatory miRNAs and proteins in MSC-EVs. In vivo, intravenously injected EVs primarily accumulated in the liver, kidney, spleen, and lung. MSC-EVs attenuated renal lesion formation, mitochondrial damage, and inflammation in mice with AKI, whereas EVs from TFAM-KD or aged MSCs resulted in poor therapeutic outcomes. Moreover, TFAM overexpression (TFAM-OE) improved the rescue effect of MSC-EVs on mitochondrial damage and inflammation to some extent. This study suggests that MSC-EVs are promising nanotherapeutics for diseases characterized by mitochondrial damage, and TFAM signaling is essential for maintaining their regenerative capacity.

Inhibition of GPR35 Preserves Mitochondrial Function After Myocardial Infarction by Targeting Calpain 1/2

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Ischemia and anoxia-induced mitochondrial impairment may be a key factor leading to heart injury during myocardial infarction (MI). Calpain 1 and 2 are involved in the MI-induced mitochondria injury. G protein-coupled receptor 35 (GPR35) could be triggered by hypoxia. Whether or not GPR35 regulates calpain 1/2 in the pathogenesis of MI is still unclear. In this study, we determined that MI increases GPR35 expression in myocardial tissue. Suppression of GPR35 protects heart from MI injury in mice through reduction of reactive oxygen species activity and mitochondria-dependent apoptosis. Further studies show that GPR35 regulates calpain 1/2. Suppression of GPR35 reduces the expression and activity of calpain 1/2, and alleviates calpain 1/2-associated mitochondrial injury to preserve cardiac function. Based on these data, we conclude that a functional inhibition of GPR35 downregulates calpain 1/2 and contributes to maintenance of cardiac function under pathologic conditions with mitochondrial disorder. In conclusion, our study showed that the identified regulation by GPR35 of calpain 1/2 has important implications for the pathogenesis of MI. Targeting the action of GPR35 and calpain 1/2 in mitochondria presents a potential therapeutic intervention for MI.

Heat shock protein 22 modulates NRF1/TFAM-dependent mitochondrial biogenesis and DRP1-sparked mitochondrial apoptosis through AMPK-PGC1α signaling pathway to alleviate the early brain injury of subarachnoid hemorrhage in rats

Mitochondrial dysfunction has been widely accepted as a detrimental factor in subarachnoid hemorrhage (SAH)-induced early brain injury (EBI), which is eminently related to poor neurologic function outcome. Previous studies have revealed that enhancement of heat shock protein 22 (hsp22) under conditions of stress is a friendly mediator of mitochondrial homeostasis, oxidative stress and apoptosis, thus accelerating neurological recovery. However, no study has confirmed whether hsp22 attenuates mitochondrial stress and apoptosis in the setting of SAH-induced EBI. Our results indicated that endogenous hsp22, p-AMPK/AMPK, PGC1α, TFAM, Nrf1 and Drp1 were significantly upregulated in cortical neurons in response to SAH, accompanied by neurologic impairment, brain edema, neuronal degeneration, lower level of mtDNA and ATP, mitochondria-cytosol translocation of cytochrome c, oxidative injury and caspase 3-involved mitochondrial apoptosis. However, exogenous hsp22 maintained neurological function, reduced brain edema, improved oxidative stress and mitochondrial apoptosis, these effects were highly dependent on PGC1α-related mitochondrial biogenesis/fission, as evidenced by co-application of PGC1α siRNA. Furthermore, we demonstrated that blockade of AMPK with dorsomorphin also compromised the neuroprotective actions of hsp22, along with the alterations of PGC1α and its associated pathway molecules. These data revealed that hsp22 exerted neuroprotective effects by salvaging mitochondrial function in an AMPK-PGC1α dependent manner, which modulates TFAM/Nrf1-induced mitochondrial biogenesis with positive feedback and DRP1-triggered mitochondrial apoptosis with negative feedback, further reducing oxidative stress and brain injury. Boosting the biogenesis and repressing excessive fission of mitochondria by hsp22 may be an efficient treatment to relieve SAH-elicited EBI.

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Hsp22 is notably upregulated in neurons at 24 h after SAH.

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Hsp22 boosts the NRF1/TFAM-dependent mitochondrial biogenesis.

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Hsp22 represses DRP1-sparked mitochondrial apoptosis.

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AMPK-PGC1α pathway is involved in hsp22-mediated neuroprotection after SAH.

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Modulation of mitochondrial biogenesis and fission may be efficient for treating SAH.