AMPK Activation Alleviates Myocardial Ischemia-Reperfusion Injury by Regulating Drp1-Mediated Mitochondrial Dynamics

Irisin attenuates cardiac injury and improves prognosis in rats with hemorrhagic shock by maintaining mitochondrial homeostasis via the AMPK/Drp1 pathway

Objective

Hemorrhagic shock (HS) is a critical clinical condition in which cardiac dysfunction and failure are leading causes of mortality. Mitochondrial dysfunction is central to the pathogenesis of cardiac dysfunction in HS. Irisin has been shown to improve mitochondrial function and protect against ischemia-reperfusion injury (IRI), but its specific effects on myocardial injury in HS are unknown. This study investigates irisin's therapeutic potential in a rat model of HS.

Methods

For in vivo studies, a rat HS model was established via controlled blood withdrawal and Animals were allocated to four groups: Sham, HS, HS + Vehicle (HS + Veh), and HS + Irisin. Physiological responses were evaluated through temporal sampling at 1, 3, and 6 h post-HS. For in vitro studies, H9c2 cardiomyocytes were exposed to oxygen-glucose deprivation to establish a hypoxic model. Cells were categorized into six groups: normoxia (N), normoxia + AMPK inhibitor compound C (N + Cc), hypoxia (H), hypoxia + Cc (H + Cc), hypoxia + irisin (H + Irisin), and hypoxia + Cc + irisin (H + Cc + Irisin). Cellular functional outcomes were analyzed following 3-h hypoxia exposure.

Results

HS significantly reduced serum irisin levels. Exogenous irisin administration enhanced survival rates, stabilized mean arterial pressure (MAP), lowered lactate (LAC) levels, improved cardiac structure and function, and reduced myocardial injury biomarkers in HS rats. Mechanistically, irisin activated AMP-activated protein kinase (AMPK) and Sirtuin 1(SIRT1), to suppress the expression of dynamin-related protein 1 (Drp1) and fission protein 1 (Fis1), while upregulating mitofusin 1 (Mfn1). This modulation of mitochondrial dynamics preserved cardiomyocyte mitochondrial membrane potential (MMP), ATP production, and structural integrity. Hypoxic H9c2 cardiomyocytes exhibited consistent results. To confirm AMPK/Drp1-dependent mechanisms, Cc was administered to inhibit irisin-induced AMPK activation. Cc abolished irisin's suppression of Drp1/Fis1 and its Mfn1 upregulation. Furthermore, Cc eliminated irisin-mediated protection in both H9c2 cardiomyocytes and mitochondria.

Conclusion

Our study demonstrates that irisin ameliorates cardiac function and enhances early prognosis in HS. These cardioprotective effects are achieved through attenuation of myocardial damage and SIRT1/AMPK/Drp1 pathway-dependent restoration of mitochondrial homeostasis.

Different types of cell death and their interactions in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury is a multifaceted process observed in patients with coronary artery disease when blood flow is restored to the heart tissue following ischemia-induced damage. Cardiomyocyte cell death, particularly through apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, is pivotal in myocardial I/R injury. Preventing cell death during the process of I/R is vital for improving ischemic cardiomyopathy. These multiple forms of cell death can occur simultaneously, interact with each other, and contribute to the complexity of myocardial I/R injury. In this review, we aim to provide a comprehensive summary of the key molecular mechanisms and regulatory patterns involved in these five types of cell death in myocardial I/R injury. We will also discuss the crosstalk and intricate interactions among these mechanisms, highlighting the interplay between different types of cell death. Furthermore, we will explore specific molecules or targets that participate in different cell death pathways and elucidate their mechanisms of action. It is important to note that manipulating the molecules or targets involved in distinct cell death processes may have a significant impact on reducing myocardial I/R injury. By enhancing researchers' understanding of the mechanisms and interactions among different types of cell death in myocardial I/R injury, this review aims to pave the way for the development of novel interventions for cardio-protection in patients affected by myocardial I/R injury.

GPR40-full agonist AM1638 alleviates palmitate-induced oxidative damage in H9c2 cells via an AMPK-dependent pathway

G protein-coupled receptor 40 (GPR40) is gaining recognition as a potential therapeutic target for several metabolic disturbances, such as hyperglycemia and excessive inflammation. GPR40 is expressed in various tissues, including the heart; however, its specific roles in cardiomyocytes remain unknown. The objective of the present study was to investigate whether treatment with AM1638, a GPR40-full agonist, reduces palmitate-mediated cell damage in H9c2 rat cardiomyocytes. AM1638 treatment increased the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and expression levels of the antioxidant molecules heme oxygenase-1 (HO-1) and nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase-1 (NQO1). Palmitate-mediated superoxide production and levels of 4-hydroxynonenal, a biomarker of oxidative stress, decreased after treatment with AM1638. Notably, palmitate-mediated disruption of mitochondrial membrane potential, lower levels of mitochondrial complex protein, and failure of adenosine triphosphate production were all recovered by treatment with AM1638. Moreover, AM1638 blocked palmitate-mediated caspase-3 cleavage and nuclear fragmentation, thereby improving cell viability. However, these AM1638-mediated beneficial effects were abrogated by treatment with Compound C, an AMPK inhibitor. These results demonstrate that AM1638, a GPR40-full agonist, ameliorates palmitate-mediated oxidative stress in H9c2 cells in an AMPK-dependent manner. [BMB Reports 2025; 58(3): 133-139].

Cardioprotective strategies in myocardial ischemia-reperfusion injury: Implications for improving clinical translation

Ischemic heart disease is the most common cause of death and disability globally which is caused by reduced or complete cessation of blood flow to a portion of the myocardium. One of its clinical manifestations is myocardial infarction, which is commonly treated by restoring of blood flow through reperfusion therapies. However, serious ischemia-reperfusion injury (IRI) can occur, significantly undermining clinical outcomes, for which there is currently no effective therapy. This review revisits several potential pharmacological IRI intervention strategies that have entered preclinical or clinical research phases. Here, we discuss what we have learned through translational failures over the years, and propose possible ways to enhance translation efficiency.

Mitochondria and myocardial ischemia/reperfusion injury: Effects of Chinese herbal medicine and the underlying mechanisms

Ischemic heart disease (IHD) is associated with high morbidity and mortality rates. Reperfusion therapy is the best treatment option for this condition. However, reperfusion can aggravate myocardial damage through a phenomenon known as myocardial ischemia/reperfusion (I/R) injury, which has recently gained the attention of researchers. Several studies have shown that Chinese herbal medicines and their natural monomeric components exert therapeutic effects against I/R injury. This review outlines the current knowledge on the pathological mechanisms through which mitochondria participate in I/R injury, focusing on the issues related to energy metabolism, mitochondrial quality control disorders, oxidative stress, and calcium. The mechanisms by which mitochondria mediate cell death have also been discussed. To develop a resource for the prevention and management of clinical myocardial I/R damage, we compiled the most recent research on the effects of Chinese herbal remedies and their monomer components.

Notoginsenoside R1 Attenuates H/R Injury in H9c2 Cells by Maintaining Mitochondrial Homeostasis

Mitochondrial homeostasis is crucial for maintaining cellular energy production and preventing oxidative stress, which is essential for overall cellular function and longevity. Mitochondrial damage and dysfunction often occur concomitantly in myocardial ischemia-reperfusion injury (MIRI). Notoginsenoside R1 (NGR1), a unique saponin from the traditional Chinese medicine Panax notoginseng, has been shown to alleviate MIRI in previous studies, though its precise mechanism remains unclear. This study aimed to elucidate the mechanisms of NGR1 in maintaining mitochondrial homeostasis in hypoxia/reoxygenation (H/R) H9c2 cells. The results showed that NGR1 pretreatment effectively increased cell survival rates post-H/R, reduced lactate dehydrogenase (LDH) leakage, and mitigated cell damage. Further investigation into mitochondria revealed that NGR1 alleviated mitochondrial structural damage, improved mitochondrial membrane permeability transition pore (mPTP) persistence, and prevented mitochondrial membrane potential (Δψm) depolarization. Additionally, NGR1 pretreatment enhanced ATP levels, increased the activity of mitochondrial respiratory chain complexes I-V after H/R, and reduced excessive mitochondrial reactive oxygen species (mitoROS) production, thereby protecting mitochondrial function. Further analysis indicated that NGR1 upregulated the expression of mitochondrial biogenesis-related proteins (PGC-1α, Nrf1, Nrf2) and mitochondrial fusion proteins (Opa1, Mfn1, Mfn2), while downregulating mitochondrial fission proteins (Fis1, Drp1) and reducing mitochondrial autophagy (mitophagy) levels, as well as the expression of mitophagy-related proteins (Pink1, Parkin, BNIP3) post-H/R. Therefore, this study showed that NGR1 can maintain mitochondrial homeostasis by regulating mitophagy, mitochondrial fission-fusion dynamics, and mitochondrial biogenesis, thereby alleviating H9c2 cell H/R injury and protecting cardiomyocytes.

Construction of AMPK-related circRNA network in mouse myocardial ischemia-reperfusion injury model

OBJECTIVE

To screen Myocardial ischemia-reperfusion Injury in mice. adenosine monophate-activatedprotein kinase (AMPK) -related differentially expressed circularRNA (circRNA) in MIRI model, Ampk-related circRNA network was drawn to provide possible ideas for the prevention and treatment of MIRI.

METHODS

The mouse MIRI model was constructed by ligation of the left anterior descending artery. After the model was successfully established, the related indicators of cardiac function were detected, and high-throughput sequencing was performed on the myocardial tissue of the mice.

RESULTS

MIRI model was successfully constructed, and two AMPK related differentially expressed loops (novel_circ_043550 and novel_circ_035243) were screened out. A circRNA-miRNA-mRNA network consisting of 2 circRNA, 28 microRNA(miRNA) and 229 messengerRNA (mRNA) was constructed.

CONCLUSIONS

This study reveals the differential expression of several AMPK-related circRNAs in MIRI in mice, and the AMPK-related circRNA regulatory network is constructed, suggesting that AMPK-related circRNA may have potential clinical application prospects as a potential molecular marker and therapeutic target for MIRI.

Crosstalk between mitochondrial homeostasis and AMPK pathway mediate the receptor-mediated cardioprotective effects of estradiol in ovariectomized female rats

Estrogen (E2) deficiency is a risk factor for cardiovascular disease (CVD), however, the exact mechanism for the E2 protective effect on CVD remains unclear. This study aimed to investigate the estrogen receptor (ER) and non-receptor mediated effects of E2 treatment on the cardiac expression of adenosine monophosphate-dependent protein kinase (AMPK), autophagic, mitophagy and mitochondrial homeostasis-regulating genes in ovariectomized (OVX) rats. Female rats were divided into two main groups; sham and bilaterally OVX rats, then each group was subdivided into four subgroups according to treatment; untreated, subcutaneously treated with E2 (30 μg/kg), or Fulvestrant (F) (5 mg/Kg), or a combination of both drugs for 28 days. The OVX rats or F-treated sham rats showed dyslipidemia, and marked disturbances in parameters of AMPK signaling, autophagy, mitophagy, mitochondrial fission, fusion and biogenesis. E2 administration to OVX or F-treated sham rats has corrected the disturbed lipid and cardiac profiles, increased AMPK, and restored the balance of cardiac autophagy, mitophagy, and mitochondrial dynamics and homeostasis. Most of these effects in OVX rats were blocked by the ER antagonist (F). Estrogen treatment has cardioprotective effects in OVX females through modulating cardiac mitochondrial homeostasis, mitophagy and autophagy and restoring the AMPK signaling pathway. As witnessed by Fulvestrant, these effects suggest the main role of ER-mediated signaling in regulating mitophagy and plasma and cardiac lipids along with the existence of a post-translational control mechanism or the involvement of estrogenic non-receptor pathway controlling the postmenopausal cardiac mitochondrial energy production machinery that needs further investigation.

NUAK: never underestimate a kinase

NUAK1 and NUAK2 belong to a family of kinases related to the catalytic α-subunits of the AMP-activated protein kinase (AMPK) complexes. Despite canonical activation by the tumour suppressor kinase LKB1, both NUAKs exhibit a spectrum of activities that favour tumour development and progression. Here, we review similarities in structure and function of the NUAKs, their regulation at gene, transcript and protein level, and discuss their phosphorylation of specific downstream targets in the context of the signal transduction pathways and biological activities regulated by each or both NUAKs.

Pretreatment with growth differentiation factor 15 augments cardioprotection by mesenchymal stem cells in myocardial infarction by improving their survival

BACKGROUND

The clinical application of mesenchymal stem cells (MSCs) in myocardial infarction (MI) is severely hampered by their poor survival. Pretreatment is a key strategy that has been adopted to promote their therapeutic efficacy. This study aimed to investigate the benefit of growth differentiation factor 15-pretreated MSCs (GDF15-MSCs) in enhancing cardiac repair following MI and to determine the underlying mechanisms.

METHODS

MSCs with or without GDF15 pretreatment were exposed to serum deprivation and hypoxia (SD/H) challenge. Apoptosis of MSCs was assessed by TUNEL staining. The conditioned media (CM) of MSCs and GDF15-MSCs was collected by centrifugation. MSCs and GDF15-MSCs were transplanted into the peri-infarct region in a mouse model of MI. Cardiac function, fibrosis and MSC survival were examined 4 weeks after MSC transplantation.

RESULTS

Pretreatment with GDF15 greatly reduced SD/H-induced apoptosis of MSCs via inhibition of reactive oxygen species (ROS) generation by attenuating mitochondrial fission. Mechanistically, GDF15 pretreatment ameliorated mitochondrial fission of MSCs under SD/H challenge by activating the AMPK pathway. These effects were partially abrogated by AMPK inhibitor. Pretreatment with GDF15 also promoted paracrine effects of MSCs in vitro, evidenced by improving tube formation of HUVECs, and inhibited the apoptosis of cardiomyocytes induced by SD/H. At 4 weeks after transplantation, compared with MSCs, GDF15 pretreatment strongly promoted the survival of MSCs in the ischemic heart with consequent enhanced cardiac function, reduced cardiac fibrosis and increased angiogenesis.

CONCLUSIONS

Our study showed that pretreatment with GDF15 promoted the cardioprotective effects of MSCs in MI via regulation of pro-survival signaling and paracrine actions. GDF15 pretreatment is an effective approach to enhance the therapeutic efficacy of MSCs in ischemic heart disease.

Unlocking mitochondrial dysfunction-associated senescence (MiDAS) with NAD+ - A Boolean model of mitochondrial dynamics and cell cycle control

The steady accumulation of senescent cells with aging creates tissue environments that aid cancer evolution. Aging cell states are highly heterogeneous. 'Deep senescent' cells rely on healthy mitochondria to fuel a strong proinflammatory secretome, including cytokines, growth and transforming signals. Yet, the physiological triggers of senescence such as reactive oxygen species (ROS) can also trigger mitochondrial dysfunction, and sufficient energy deficit to alter their secretome and cause chronic oxidative stress - a state termed Mitochondrial Dysfunction-Associated Senescence (MiDAS). Here, we offer a mechanistic hypothesis for the molecular processes leading to MiDAS, along with testable predictions. To do this we have built a Boolean regulatory network model that qualitatively captures key aspects of mitochondrial dynamics during cell cycle progression (hyper-fusion at the G1/S boundary, fission in mitosis), apoptosis (fission and dysfunction) and glucose starvation (reversible hyper-fusion), as well as MiDAS in response to SIRT3 knockdown or oxidative stress. Our model reaffirms the protective role of NAD+ and external pyruvate. We offer testable predictions about the growth factor- and glucose-dependence of MiDAS and its reversibility at different stages of reactive oxygen species (ROS)-induced senescence. Our model provides mechanistic insights into the distinct stages of DNA-damage induced senescence, the relationship between senescence and epithelial-to-mesenchymal transition in cancer and offers a foundation for building multiscale models of tissue aging.

Doxorubicin-related cardiotoxicity: review of fundamental pathways of cardiovascular system injury

Over the years, advancements in the field of oncology have made remarkable strides in enhancing the efficacy of medical care for patients with cancer. These modernizations have resulted in prolonged survival and improved the quality of life for these patients. However, this progress has also been accompanied by escalation in mortality rates associated with anthracycline chemotherapy. Anthracyclines, which are known for their potent antitumor properties, are notorious for their substantial cardiotoxic potential. Remarkably, even after 6 decades of research, a conclusive solution to protect the cardiovascular system against doxorubicin-induced damage has not yet been established. A comprehensive understanding of the pathophysiological processes driving cardiotoxicity combined with targeted research is crucial for developing innovative cardioprotective strategies. This review seeks to explain the mechanisms responsible for structural and functional alterations in doxorubicin-induced cardiomyopathy.

Mitochondria-Associated Organelle Crosstalk in Myocardial Ischemia/Reperfusion Injury

Organelle damage is a significant contributor to myocardial ischemia/reperfusion (I/R) injury. This damage often leads to disruption of endoplasmic reticulum protein regulatory programs and dysfunction of mitochondrial energy metabolism. Mitochondria and endoplasmic reticulum are seamlessly connected through the mitochondrial-associated endoplasmic reticulum membrane (MAM), which serves as a crucial site for the exchange of organelles and metabolites. However, there is a lack of reports regarding the communication of information and metabolites between mitochondria and related organelles, which is a crucial factor in triggering myocardial I/R damage. To address this research gap, this review described the role of crosstalk between mitochondria and the correlative organelles such as endoplasmic reticulum, lysosomal and nuclei involved in reperfusion injury of the heart. In summary, this review aims to provide a comprehensive understanding of the crosstalk between organelles in myocardial I/R injury, with the ultimate goal of facilitating the development of targeted therapies based on this knowledge.

Nimbolide protects against diabetic cardiomyopathy by regulating endoplasmic reticulum stress and mitochondrial function via the Akt/mTOR pathway

Nimbolide has been demonstrated to possess protective properties against gestational diabetes mellitus and diabetic retinopathy. However, the role and molecular mechanism of nimbolide in diabetic cardiomyopathy (DCM) remain unknown. Diabetes was induced in rats via a single injection of streptozotocin (STZ) and then the diabetic rats were administered nimbolide (5 mg/kg and 20 mg/kg) or dimethyl sulfoxide daily for 12 weeks. H9c2 cardiomyocytes were exposed to high glucose (25 mM glucose) to mimic DCM in vitro. The protective effects of nimbolide against DCM were evaluated in vivo and in vitro. The potential molecular mechanism of nimbolide in DCM was further explored. We found that nimbolide dose-dependently decreased blood glucose and improved body weight of diabetic rats. Additionally, nimbolide dose-dependently improved cardiac function, alleviated myocardial injury/fibrosis, and inhibited endoplasmic reticulum (ER) stress and apoptosis in diabetic rats. Moreover, nimbolide dose-dependently improved mitochondrial function and activated the Akt/mTOR signaling. We consistently demonstrated the cardioprotective effects of nimbolide in an in vitro model of DCM. The involvement of ER stress and mitochondrial pathways were further confirmed by using inhibitors of ER stress and mitochondrial division. By applying a specific Akt inhibitor SC66, the cardioprotective effects of nimbolide were partially blocked. Our study indicated that nimbolide alleviated DCM by activating Akt/mTOR pathway. Nimbolide may be a novel therapeutic agent for DCM treatment.

Modulating mitochondrial dynamics ameliorates left ventricular dysfunction by suppressing diverse cell death pathways after diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) triggers a detrimental shift in mitochondrial dynamics, characterized by increased fission and decreased fusion, contributing to cardiomyocyte apoptosis and cardiac dysfunction. This study investigated the impact of modulating mitochondrial dynamics on DCM outcomes and underlying mechanisms in a mouse model. DCM induction led to upregulation of fission genes (Drp1, Mff, Fis1) and downregulation of fusion genes (Mfn1, Mfn2, Opa1). Inhibiting fission with Mdivi-1 or promoting fusion with Ginsenoside Rg1 preserved cardiac function, as evidenced by improved left ventricular ejection fraction (LVEF), fractional shortening (FS), and E/A ratio. Both treatments also reduced infarct size and attenuated cardiomyocyte apoptosis, indicated by decreased caspase-3 activity. Mechanistically, Mdivi-1 enhanced mitochondrial function by improving mitochondrial membrane potential, reducing reactive oxygen species (ROS) production, and increasing ATP generation. Ginsenoside Rg1 also preserved mitochondrial integrity and function under hypoxic conditions in HL-1 cardiomyocytes. These findings suggest that restoring the balance of mitochondrial dynamics through pharmacological interventions targeting either fission or fusion may offer a promising therapeutic strategy for mitigating MI-induced cardiac injury and improving patient outcomes.

Activation AMPK in Hypothalamic Paraventricular Nucleus Improves Renovascular Hypertension Through ERK1/2-NF-κB Pathway

Hypertension is a globally prevalent disease, but the pathogenesis remains largely unclear. AMP-activated protein kinase (AMPK) is a nutrition-sensitive signal of cellular energy metabolism, which has a certain influence on the development of hypertension. Previously, we found a down-regulation of the phosphorylated (p-) form of AMPK, and the up-regulation of the angiotensin II type 1 receptor (AT1-R) and that of p-ERK1/2 in the hypothalamic paraventricular nucleus (PVN) of hypertensive rats. However, the exact mechanism underlying the relationship between AMPK and AT1-R in the PVN during hypertension remains unclear. Thus, we hypothesized that AMPK modulates AT1-R through the ERK1/2-NF-κB pathway in the PVN, thereby inhibiting sympathetic nerve activity and improving hypertension. To examine this hypothesis, we employed a renovascular hypertensive animal model developed via two-kidney, one-clip (2K1C) and sham-operated (SHAM). Artificial cerebrospinal fluid (aCSF), used as vehicle, or 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide (AICAR, an AMPK activator, 60 μg/day) was microinjected bilaterally in the PVN of these rats for 4 weeks. In 2K1C rats, there an increase in systolic blood pressure (SBP) and circulating norepinephrine (NE). Also, the hypertensive rats had lowered expression of p-AMPK and p-AMPK/AMPK, elevated expression of p-ERK1/2, p-ERK1/2/ERK1/2 and AT1-R, increased NF-κB p65 activity in the PVN compared with the levels of these biomarkers in SHAM rats. Four weeks of bilateral PVN injection of AMPK activator AICAR, attenuated the NE level and SBP, increased the expression of p-AMPK and p-AMPK/AMPK, lessened the NF-κB p65 activity, decreased the expression of p-ERK1/2, p-ERK1/2/ERK1/2 and AT1-R in the PVN of 2K1C rats. Data from this study imply that the activation of AMPK within the PVN suppressed AT1-R expression through inhibiting the ERK1/2-NF-κB pathway, decreased the activity of the sympathetic nervous system, improved hypertension.

BMSC‑derived exosome‑mediated miR‑25‑3p delivery protects against myocardial ischemia/reperfusion injury by constraining M1‑like macrophage polarization

Myocardial ischemia/reperfusion injury (MIRI) is a significant challenge in the management of myocardial ischemic disease. Extensive evidence suggests that the macrophage‑mediated inflammatory response may play a vital role in MIRI. Mesenchymal stem cells and, in particular, exosomes derived from these cells, may be key mediators of myocardial injury and repair. However, whether exosomes protect the heart by regulating the polarization of macrophages and the exact mechanisms involved are poorly understood. The present study aimed to determine whether exosomes secreted by bone marrow mesenchymal stem cells (BMSC‑Exo) harboring miR‑25‑3p can alter the phenotype of macrophages by affecting the JAK2/STAT3 signaling pathway, which reduces the inflammatory response and protects against MIRI. An in vivo MIRI model was established in rats by ligating the anterior descending region of the left coronary artery for 30 min followed by reperfusion for 120 min, and BMSC‑Exo carrying miR‑25‑3p (BMSC‑Exo‑25‑3p) were administered through tail vein injection. A hypoxia‑reoxygenation model of H9C2 cells was established, and the cells were cocultured with BMSC‑Exo‑25‑3p in vitro. The results of the present study demonstrated that BMSC‑Exo or BMSC‑Exo‑25‑3p could be taken up by cardiomyocytes in vivo and H9C2 cells in vitro. BMSC‑Exo‑25‑3p demonstrated powerful cardioprotective effects by decreasing the cardiac infarct size, reducing the incidence of malignant arrhythmias and attenuating myocardial enzyme activity, as indicated by lactate dehydrogenase and creatine kinase levels. It induced M1‑like macrophage polarization after myocardial ischemia/reperfusion (I/R), as evidenced by the increase in iNOS expression through immunofluorescence staining and upregulation of proinflammatory cytokines through RT‑qPCR, such as interleukin‑1β (IL‑1β) and interleukin‑6 (IL‑6). As hypothesized, BMSC‑Exo‑25‑3p inhibited M1‑like macrophage polarization and proinflammatory cytokine expression while promoting M2‑like macrophage polarization. Mechanistically, the JAK2/STAT3 signaling pathway was activated after I/R in vivo and in LPS‑stimulated macrophages in vitro, and BMSC‑Exo‑25‑3p pretreatment inhibited this activation. The results of the present study indicate that the attenuation of MIRI by BMSC‑Exo‑25‑3p may be related to JAK2/STAT3 signaling pathway inactivation and subsequent inhibition of M1‑like macrophage polarization.

Peptide PDRPS6 attenuates myocardial ischemia injury by improving mitochondrial function

Mitochondrial dynamics play a crucial role in myocardial ischemia-reperfusion (I/R) injury, where an imbalance between fusion and fission processes occurs. However, effective measures to regulate mitochondrial dynamics in this context are currently lacking. Peptide derived from the 40 S ribosomal protein S6 (PDRPS6), a peptide identified via peptidomics, is associated with hypoxic stress. This study aimed to investigate the function and mechanism of action of PDRPS6 in I/R injury. In vivo, PDRPS6 ameliorated myocardial tissue injury and cardiomyocyte apoptosis and decreased cardiac function induced by I/R injury in rats. PDRPS6 supplementation significantly reduced apoptosis in vitro. Mechanistically, PDRPS6 improved mitochondrial function by decreasing reactive oxygen species (ROS) levels, maintaining mitochondrial membrane potential (MMP), and inhibiting mitochondrial fission. Pull-down assay analyses revealed that phosphoglycerate mutase 5 (PGAM5) may be the target of PDRPS6, which can lead to the dephosphorylation of dynamin-related protein1 (Drp1) at ser616 site. Overexpression of PGAM5 partially eliminated the effect of PDRPS6 on improving mitochondrial function. These findings suggest that PDRPS6 supplementation is a novel method for treating myocardial injuries caused by I/R.

MELATONIN ATTENUATES RENAL ISCHEMIA-REPERFUSION INJURY BY REGULATING MITOCHONDRIAL DYNAMICS AND AUTOPHAGY THROUGH AMPK/DRP1

ABSTRACT

Ischemia-reperfusion injury (IRI) often stems from an imbalance between mitochondrial dynamics and autophagy. Melatonin mitigates IRI by regulating mitochondrial dynamics. However, the precise molecular mechanism underlying the role of melatonin in reducing IRI through modulating mitochondrial dynamics remains elusive. The objective of this study was to investigate whether pretreatment with melatonin before IRI confers protective effects by modulating mitochondrial dynamics and mitophagy. Melatonin pretreatment was administered to HK-2 cells and live rats before subjecting them to hypoxia-reoxygenation or IRI, respectively. Cells and rat kidney models were evaluated for markers of oxidative stress, autophagy, mitochondrial dynamics, and the expression of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and phospho-AMPKα (P-AMPK). After renal IRI, increased mitochondrial fission and autophagy were observed, accompanied by exacerbated cellular oxidative stress injury and aggravated mitochondrial dysfunction. Nevertheless, melatonin pretreatment inhibited mitochondrial fission, promoted mitochondrial fusion, and attenuated autophagy levels. This intervention was correlated with a notable reduction in oxidative stress injury and remarkable restoration of mitochondrial functionality. Ischemia-reperfusion injury led to a decline in P-AMPK levels, whereas melatonin pretreatment increased the level of P-AMPK levels. Silencing AMPK with small interfering RNA exacerbated mitochondrial damage, and in this context, melatonin pretreatment did not alleviate mitochondrial fission or autophagy levels but resulted in sustained oxidative stress damage. Collectively, these findings indicate that melatonin pretreatment shields the kidneys from IRI by mitigating excessive mitochondrial fission, moderating autophagy levels, and preserving appropriate mitochondrial fission, all in an AMPK-dependent manner.

Novel roles of κ-opioid receptor in myocardial ischemia-reperfusion injury

Acute heart attack is the primary cause of cardiovascular-related death worldwide. A common treatment is reperfusion of ischemic tissue, which can cause irreversible damage to the myocardium. The number of mitochondria in cardiomyocytes is large, which generate adenosine triphosphate (ATP) to sustain proper cardiac contractile function, and mitochondrial dysfunction plays a crucial role in cell death during myocardial ischemia-reperfusion, leading to an increasing number of studies investigating the impact of mitochondria on ischemia-reperfusion injury. The disarray of mitochondrial dynamics, excessive Ca2+ accumulation, activation of mitochondrial permeable transition pores, swelling of mitochondria, ultimately the death of cardiomyocyte are the consequences of ischemia-reperfusion injury. κ-opioid receptors can alleviate mitochondrial dysfunction, regulate mitochondrial dynamics, mitigate myocardial ischemia-reperfusion injury, exert protective effects on myocardium. The mechanism of κ-OR activation during myocardial ischemia-reperfusion to regulate mitochondrial dynamics and reduce myocardial ischemia-reperfusion injury will be discussed, so as to provide theoretical basis for the protection of ischemic myocardium.

WTAP-mediated m6A modification of lncRNA Snhg1 improves myocardial ischemia-reperfusion injury via miR-361-5p/OPA1-dependent mitochondrial fusion

BACKGROUND

Myocardial ischemia-reperfusion injury (MIRI) is caused by reperfusion after ischemic heart disease. LncRNA Snhg1 regulates the progression of various diseases. N6-methyladenosine (m6A) is the frequent RNA modification and plays a critical role in MIRI. However, it is unclear whether lncRNA Snhg1 regulates MIRI progression and whether the lncRNA Snhg1 was modified by m6A methylation.

METHODS

Mouse cardiomyocytes HL-1 cells were utilized to construct the hypoxia/reoxygenation (H/R) injury model. HL-1 cell viability was evaluated utilizing CCK-8 method. Cell apoptosis, mitochondrial reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were quantitated utilizing flow cytometry. RNA immunoprecipitation and dual-luciferase reporter assays were applied to measure the m6A methylation and the interactions between lncRNA Snhg1 and targeted miRNA or target miRNAs and its target gene. The I/R mouse model was constructed with adenovirus expressing lncRNA Snhg1. HE and TUNEL staining were used to evaluate myocardial tissue damage and apoptosis.

RESULTS

LncRNA Snhg1 was down-regulated after H/R injury, and overexpressed lncRNA Snhg1 suppressed H/R-stimulated cell apoptosis, mitochondrial ROS level and polarization. Besides, lncRNA Snhg1 could target miR-361-5p, and miR-361-5p targeted OPA1. Overexpressed lncRNA Snhg1 suppressed H/R-stimulated cell apoptosis, mitochondrial ROS level and polarization though the miR-361-5p/OPA1 axis. Furthermore, WTAP induced lncRNA Snhg1 m6A modification in H/R-stimulated HL-1 cells. Moreover, enforced lncRNA Snhg1 repressed I/R-stimulated myocardial tissue damage and apoptosis and regulated the miR-361-5p and OPA1 levels.

CONCLUSION

WTAP-mediated m6A modification of lncRNA Snhg1 regulated MIRI progression through modulating myocardial apoptosis, mitochondrial ROS production, and mitochondrial polarization via miR-361-5p/OPA1 axis, providing the evidence for lncRNA as the prospective target for alleviating MIRI progression.

Unlocking Mitochondrial Dysfunction-Associated Senescence (MiDAS) with NAD + - a Boolean Model of Mitochondrial Dynamics and Cell Cycle Control

The steady accumulation of senescent cells with aging creates tissue environments that aid cancer evolution. Aging cell states are highly heterogeneous. 'Deep senescent' cells rely on healthy mitochondria to fuel a strong proinflammatory secretome, including cytokines, growth and transforming signals. Yet, the physiological triggers of senescence such as the reactive oxygen species (ROS) can also trigger mitochondrial dysfunction, and sufficient energy deficit to alter their secretome and cause chronic oxidative stress - a state termed Mitochondrial Dysfunction-Associated Senescence (MiDAS). Here, we offer a mechanistic hypothesis for the molecular processes leading to MiDAS, along with testable predictions. To do this we have built a Boolean regulatory network model that qualitatively captures key aspects of mitochondrial dynamics during cell cycle progression (hyper-fusion at the G1/S boundary, fission in mitosis), apoptosis (fission and dysfunction) and glucose starvation (reversible hyper-fusion), as well as MiDAS in response to SIRT3 knockdown or oxidative stress. Our model reaffirms the protective role of NAD + and external pyruvate. We offer testable predictions about the growth factor- and glucose-dependence of MiDAS and its reversibility at different stages of reactive oxygen species (ROS)-induced senescence. Our model provides mechanistic insights into the distinct stages of DNA-damage induced senescence, the relationship between senescence and epithelial-to-mesenchymal transition in cancer and offers a foundation for building multiscale models of tissue aging.

Highlights

Boolean regulatory network model reproduces mitochondrial dynamics during cell cycle progression, apoptosis, and glucose starvation. Model offers a mechanistic explanation for the positive feedback loop that locks in Mitochondrial Dysfunction-Associated Senescence (MiDAS), involving autophagy-resistant, hyperfused, dysfunctional mitochondria. Model reproduces ROS-mediated mitochondrial dysfunction and suggests that MiDAS is part of the early phase of damage-induced senescence. Model predicts that cancer-driving mutations that bypass the G1/S checkpoint generally increase the incidence of MiDAS, except for p53 loss.

Dapagliflozin Suppresses Isoprenaline-Induced Cardiac Hypertrophy Through Inhibition of Mitochondrial Fission

ABSTRACT

Dapagliflozin (DAPA) is a novel oral hypoglycemic agent, and there is increasing evidence that DAPA has a protective effect against cardiovascular disease. The study aimed to investigate how DAPA inhibits cardiac hypertrophy and explore its potential mechanisms. By continuously infusing isoprenaline (ISO) for 2 weeks using a subcutaneous osmotic pump, a cardiac hypertrophic model was established in male C57BL/6 mice. On day 14 after surgery, echocardiography showed that left ventricle mass (LV mass), interventricular septum, left ventricle posterior wall diastole, and left ventricular posterior wall systole were significantly increased, and ejection fraction was decreased compared with control mice. Masson and Wheat Germ Agglutinin staining indicated enhanced myocardial fibrosis and cell morphology compared with control mice. Importantly, these effects were inhibited by DAPA treatment in ISO-induced mice. In H9c2 cells and neonatal rat cardiomyocytes, we found that mitochondrial fragmentation and mitochondrial oxidative stress were significantly augmented in the ISO-induced group. However, DAPA rescued the cardiac hypertrophy in ISO-induced H9c2 cells and neonatal rat cardiomyocytes. Mechanistically, we found that DAPA restored the PIM1 activity in ISO-induced H9c2 cells and subsequent increase in dynamin-associated protein 1 (Drp1) phosphorylation at S616 and decrease in Drp1 phosphorylation at S637 in ISO-induced cells. We found that DAPA mitigated ISO-induced cardiac hypertrophy by suppressing Drp1-mediated mitochondrial fission in a PIM1-dependent fashion.

Tangeretin attenuates acute lung injury in septic mice by inhibiting ROS-mediated NLRP3 inflammasome activation via regulating PLK1/AMPK/DRP1 signaling axis

OBJECTIVE

NLRP3 inflammasome-mediated pyroptosis of macrophage acts essential roles in the progression of sepsis-induced acute lung injury (ALI). Tangeretin (TAN), enriched in citrus fruit peel, presents anti-oxidative and anti-inflammatory effects. Here, we aimed to explore the potentially protective effect of TAN on sepsis-induced ALI, and the underlying mechanism of TAN in regulating NLRP3 inflammasome.

MATERIAL AND METHODS

The effect of TAN on sepsis-induced ALI and NLRP3 inflammasome-mediated pyroptosis of macrophage were examined in vivo and in vitro using a LPS-treated mice model and LPS-induced murine macrophages, respectively. The mechanism of TAN regulating the activation of NLRP3 inflammasome in sepsis-induced ALI was investigated with HE staining, Masson staining, immunofluorescent staining, ELISA, molecular docking, transmission electron microscope detection, qRT-PCR, and western blot.

RESULTS

TAN could evidently attenuate sepsis-induced ALI in mice, evidenced by reducing pulmonary edema, pulmonary congestion and lung interstitial fibrosis, and inhibiting macrophage infiltration in the lung tissue. Besides, TAN significantly suppressed inflammatory cytokine IL-1β and IL-18 expression in the serum or bronchoalveolar lavage fluid (BALF) samples of mice with LPS-induced ALI, and inhibited NLRP3 inflammasome-mediated pyroptosis of macrophages. Furthermore, we found TAN inhibited ROS production, preserved mitochondrial morphology, and alleviated excessive mitochondrial fission in LPS-induced ALI in mice. Through bioinformatic analysis and molecular docking, Polo-like kinase 1 (PLK1) was identified as a potential target of TAN for treating sepsis-induced ALI. Moreover, TAN significantly inhibited the reduction of PLK1 expression, AMP-activated protein kinase (AMPK) phosphorylation, and Dynamin related protein 1 (Drp1) phosphorylation (S637) in LPS-induced ALI in mice. In addition, Volasertib, a specific inhibitor of PLK1, abolished the protective effects of TAN against NLRP3 inflammasome-mediated pyroptosis of macrophage and lung injury in the cell and mice septic models.

CONCLUSION

TAN attenuates sepsis-induced ALI by inhibiting ROS-mediated NLRP3 inflammasome activation via regulating PLK1/AMPK/DRP1 signaling axis, and TAN is a potentially therapeutic candidate against ALI through inhibiting pyroptosis.

Pharmacological Activation of AMPK Prevents Drp1-mediated Mitochondrial Fission and Alleviates Hepatic Steatosis In vitro

BACKGROUND

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide. Adenosine monophosphate-activated protein kinase (AMPK) activation is beneficial for NAFLD treatment. Recent studies show the excessive fission of mitochondria during NAFLD progression, so targeting mitochondria dynamics may be a possible target for NAFLD. Still, little is known about whether AMPK regulates mitochondrial dynamics in hepar.

OBJECTIVE

This study investigated whether AMPK activation alleviates hepatic steatosis by regulating mitochondrial dynamics mediated by GTPase dynamin-related protein 1 (Drp1).

METHODS

Human hepatocyte line L-02 cells were cultured and subjected to palmitic acid (PA) treatment for 24 h to establish a hepatic steatosis model in vitro, which was pre-treated with different tool drugs. Hepatocyte function, hepatocyte lipid content, mitochondrial reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) were examined. The expression levels of genes and proteins associated with mitochondrial dynamics were assessed using reverse transcription-quantitative PCR and western blotting.

RESULTS

The results indicated that 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR), an AMPK activator, improved hepatocyte function, as demonstrated by decreased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity (P<0.05 or P<0.01). In addition, AICAR decreased total cholesterol (TC) and triglyceride (TG) content and lipid deposition in hepatocytes (P<0.01); decreased ROS production; improved MMP (P<0.01); reduced fission-1 (Fis1) and mitochondrial fission factor (Mff) mRNA expression; and downregulated p-Drp1 (Ser 616) protein expression. In contrast, AICAR increased mitochondrial fusion factor mitofusin-1 (Mfn1) and mitofusin-2 (Mfn2) mRNA expression and upregulated p-Drp1 (Ser 637) protein expression. Mdivi-1, a Drp-1 inhibitor, was used to confirm whether mitochondrial dynamics regulated by Drp1-mediated the role of AICAR. Similar to AICAR, Mdivi-1 improved hepatocyte function and MMP significantly, decreased ROS production and lipid deposition, downregulated Fis1 and Mff mRNA expression, downregulated p-Drp1 (Ser 616) protein expression, and enhanced Mfn1 and Mfn2 mRNA and p-Drp1 (Ser 637) protein expression. However, Compound C, an AMPKspecific inhibitor, had less impact on the protective effect of Mdivi-1.

CONCLUSION

The results demonstrated that AMPK activation has a protective effect on hepatic steatosis in vitro, largely dependent on the inhibition of Drp1-mediated mitochondrial fission.

Sestrin2 levels in patients with anxiety and depression myocardial infarction was up-regulated and suppressed inflammation and ferroptosis by LKB1-mediated AMPK activation

Although great progress has been made in the diagnosis and treatment of acute myocardial infarction (AMI) in recent years, its morbidity and mortality are still relatively high. In this study, we explain that the function of Sestrin2 gene in Anxiety and Depression Myocardial infarction and its possible mechanism. 26 patients with Anxiety and Depression Myocardial infarction (ADMI) and 26 normal volunteers were collected from our hospital. All mice anaesthetized using 50 mg/kg of pentobarbital sodium and the left anterior descending arteries (LAD) were ligated to induce myocardial infarction. H9c2 cells were stimulated with 5% oxygen (O2) and 5% carbon dioxide (CO2) and 90% N2 for 24 h. The serum expression of Sestrin2 in patients with ADMI was up-regulated. Sestrin2 gene up-regulation reduced collagen I/II and KEAP1 mRNA expressions, and increased GPX4 and Nrf2 mRNA expressions in vitro model of AMI. Down-regulation of Sestrin2 increased collagen I/II and KEAP1 mRNA expressions, and decreased GPX4 and Nrf2 mRNA expressions in vitro model of AMI. These data confirmed that Sestrin2 reduced inflammation and ferroptosis in model of ADMI by LKB1-mediated AMPK activation. This infers that Sestrin2 is potential target to be used in the treatment of premature AMI.

Targeting mitochondrial shape: at the heart of cardioprotection

There remains an unmet need to identify novel therapeutic strategies capable of protecting the myocardium against the detrimental effects of acute ischemia-reperfusion injury (IRI), to reduce myocardial infarct (MI) size and prevent the onset of heart failure (HF) following acute myocardial infarction (AMI). In this regard, perturbations in mitochondrial morphology with an imbalance in mitochondrial fusion and fission can disrupt mitochondrial metabolism, calcium homeostasis, and reactive oxygen species production, factors which are all known to be critical determinants of cardiomyocyte death following acute myocardial IRI. As such, therapeutic approaches directed at preserving the morphology and functionality of mitochondria may provide an important strategy for cardioprotection. In this article, we provide an overview of the alterations in mitochondrial morphology which occur in response to acute myocardial IRI, and highlight the emerging therapeutic strategies for targeting mitochondrial shape to preserve mitochondrial function which have the future therapeutic potential to improve health outcomes in patients presenting with AMI.

Diallyl trisulfide improves spinal cord ischemia-reperfusion injury damage by activating AMPK to stabilize mitochondrial function

BACKGROUND

Spinal cord ischemia-reperfusion injury (SCII) is a catastrophic event, which can cause paraplegia in severe cases. In the reperfusion stage, oxidative stress was up-regulated, which aggravated the injury and apoptosis of neurons. As the main active ingredient of garlic, diallyl trisulfide (DATS) displays strong antioxidant capacity. However, it is unknown whether DATS can protect the neurons of SCII.

MATERIALS AND METHODS

In this study, the descending aorta at the distal end of the left subclavian artery was ligated and perfused again after 14 min. Samples including blood and spinal cord (L2-L5) were taken 24 h later for morphological and biochemical examination.

RESULTS

After SCII, the rats showed motor dysfunction, increase apoptosis, malondialdehyde content, mitochondrial biogenesis and dynamic balance disorder. After the application of DATS, the adenosine monophosphate activated protein kinase (AMPK) was activated, the mitochondrial damage was improved, the oxidative stress was weakened, and the neuronal damage was recovered to some extent. However, the addition of compound C significantly weakened the protective effect of DATS.

CONCLUSION

Oxidative stress caused by mitochondrial damage was one of the important mechanisms of neuronal damage in SCII. DATS could activate AMPK, stabilize mitochondrial biogenesis and dynamic balance, and reduce neuronal damage caused by oxidative stress.

Preventing mitochondrial reverse electron transport as a strategy for cardioprotection

In the context of myocardial infarction, the burst of superoxide generated by reverse electron transport (RET) at complex I in mitochondria is a crucial trigger for damage during ischaemia/reperfusion (I/R) injury. Here we outline the necessary conditions for superoxide production by RET at complex I and how it can occur during reperfusion. In addition, we explore various pathways that are implicated in generating the conditions for RET to occur and suggest potential therapeutic strategies to target RET, aiming to achieve cardioprotection.

Unveiling the potential of mitochondrial dynamics as a therapeutic strategy for acute kidney injury

Acute Kidney Injury (AKI), a critical clinical syndrome, has been strongly linked to mitochondrial malfunction. Mitochondria, vital cellular organelles, play a key role in regulating cellular energy metabolism and ensuring cell survival. Impaired mitochondrial function in AKI leads to decreased energy generation, elevated oxidative stress, and the initiation of inflammatory cascades, resulting in renal tissue damage and functional impairment. Therefore, mitochondria have gained significant research attention as a potential therapeutic target for AKI. Mitochondrial dynamics, which encompass the adaptive shifts of mitochondria within cellular environments, exert significant influence on mitochondrial function. Modulating these dynamics, such as promoting mitochondrial fusion and inhibiting mitochondrial division, offers opportunities to mitigate renal injury in AKI. Consequently, elucidating the mechanisms underlying mitochondrial dynamics has gained considerable importance, providing valuable insights into mitochondrial regulation and facilitating the development of innovative therapeutic approaches for AKI. This comprehensive review aims to highlight the latest advancements in mitochondrial dynamics research, provide an exhaustive analysis of existing studies investigating the relationship between mitochondrial dynamics and acute injury, and shed light on their implications for AKI. The ultimate goal is to advance the development of more effective therapeutic interventions for managing AKI.

Schisanhenol Attenuates OxLDL-Induced Endothelial Dysfunction via an AMPK-Dependent Mechanism

Atherosclerotic cardiovascular diseases, commonly known as the formation of fibrofatty lesions in the artery wall, are the leading causes of death globally. Oxidized low-density lipoprotein (oxLDL) is one of the major components of atherosclerotic plaques. It is evident that dietary supplementation containing sources of antioxidants can prevent atherogenic diseases. Schisanhenol (SAL), a dibenzocyclooctene lignin, has been shown to attenuate oxLDL-induced apoptosis and the generation of reactive oxygen species (ROS) in endothelial cells. However, the underlying molecular mechanisms are still largely unknown. In this study, human umbilical vein endothelial cells (HUVECs) were pre-treated with SAL and oxLDL. Our results showed that adenosine monophosphate-activated protein kinase (AMPK) phosphorylation was enhanced in cells pre-treated with SAL in time-dependent and dose-dependent manners. Subsequently, oxLDL-induced AMPK dephosphorylation and protein kinase C (PKC) phosphorylation were significantly reversed in the presence of SAL. In addition, SAL treatment led to an inhibiting effect on the oxLDL-induced membrane assembly of NADPH oxidase subunits, and a similar effect was observed in ROS generation. This effect was further confirmed using knockdown AMPK with small interfering RNA (siRNA) and pharmaceutical reagents, such as the AMPK activator (AICAR), PKC inhibitor (Gö 6983), and ROS inhibitor (DPI). Furthermore, the oxLDL-induced intracellular calcium rise and the potential collapse of the mitochondrial membrane reduced the Bcl-2/Bax ratio, and released cytochrome c from the mitochondria, leading to the subsequent activation of caspase-3 in HUVECs, which were also markedly suppressed by SAL pretreatment. The results mentioned above may provide additional insights into the possible molecular mechanisms underlying the cardiovascular protective effects of SAL.

Cadmium exposure caused cardiotoxicity in common carps (Cyprinus carpio L.): miR-9-5p, oxidative stress, energetic impairment, mitochondrial division/fusion imbalance, inflammation, and autophagy

Cadmium (Cd), a toxic heavy metal pollutant, is a threat to human and eatable fish health. Common carps are widely cultivated and eaten by humans. However, there are no reports about Cd-damaged common carp hearts. Our experiment attempted to investigate the cardiotoxicity of Cd to common carps by establishing a common carp Cd exposure model. Our results showed that Cd injured hearts. Moreover, Cd treatment induced autophagy via miR-9-5p/Sirt1/mTOR/ULK1 pathway. Cd exposure caused oxidant/antioxidant imbalance and oxidative stress; and led to energetic impairment. Energetic impairment partook in oxidative stress-mediated autophagy through AMPK/mTOR/ULK1 pathway. Furthermore, Cd caused mitochondrial division/fusion imbalance and resulted in inflammatory injury via NF-κB-COX-2-PTGEs and NF-κB-COX-2-TNF-α pathways. Oxidative stress mediated mitochondrial division/fusion imbalance, further induced inflammation and autophagy via OPA1/NF-κB-COX-2-TNF-α-Beclin1 and OPA1/NF-κB-COX-2-TNF-α/P62 pathways under Cd treatment. Taken together, miR-9-5p, oxidative stress, energetic impairment, mitochondrial division/fusion imbalance, inflammation, and autophagy participated in the mechanism of Cd-cardiotoxicity to common carps. Our study revealed harmful effect of Cd on hearts, and provided new information for researches of environmental pollutant toxicity.

The role of Mitochondrial Fission Proteins in Mitochondrial Dynamics in Kidney Disease

Mitochondria have many forms and can change their shape through fusion and fission of the outer and inner membranes, called "mitochondrial dynamics". Mitochondrial outer membrane proteins, such as mitochondrial fission protein 1 (FIS1), mitochondrial fission factor (MFF), mitochondrial 98 dynamics proteins of 49 kDa (MiD49), and mitochondrial dynamics proteins of 51 kDa (MiD51), can aggregate at the outer mitochondrial membrane and thus attract Dynamin-related protein 1 (DRP1) from the cytoplasm to the outer mitochondrial membrane, where DRP1 can perform a scissor-like function to cut a complete mitochondrion into two separate mitochondria. Other organelles can promote mitochondrial fission alongside mitochondria. FIS1 plays an important role in mitochondrial-lysosomal contacts, differentiating itself from other mitochondrial-fission-associated proteins. The contact between the two can also induce asymmetric mitochondrial fission. The kidney is a mitochondria-rich organ, requiring large amounts of mitochondria to produce energy for blood circulation and waste elimination. Pathological increases in mitochondrial fission can lead to kidney damage that can be ameliorated by suppressing their excessive fission. This article reviews the current knowledge on the key role of mitochondrial-fission-associated proteins in the pathogenesis of kidney injury and the role of their various post-translational modifications in activation or degradation of fission-associated proteins and targeted drug therapy.