Mitochondrial networking in diabetic left ventricle cardiomyocytes

Green Tea Polyphenols Alleviate Kidney Injury Induced by Di(2-Ethylhexyl) Phthalate in Mice

INTRODUCTION

Di(2-ethylhexyl) phthalate (DEHP) is a common plasticizer. Studies have revealed that DEHP exposure can cause kidney damage. Green tea is among the most popular beverages in China. Green tea polyphenols (GTPs) have been proven to have therapeutic effects on organ damage induced by heavy metal exposure. However, few studies have reported on GTP-relieving DEHP-induced kidney damage.

METHODS

C57BL/6J male mice aged 6-8 weeks were treated with distilled water (control group), 1,500 mg/kg/d DEHP + corn oil (model group), 1,500 mg/kg/d DEHP + corn oil + 70 mg/kg GTP (treatment group), corn oil (oil group), and 70 mg/kg GTP (GTP group) by gavage for 8 weeks, respectively. The renal function of mice and renal tissue histopathology of each group were evaluated. The renal tissues of mice in the model, treatment, and control groups were analyzed using high-throughput sequencing. We calculated the differentially expressed microRNAs (miRNAs) and messenger RNAs (mRNAs) using the limma R package, the CIBERSORT algorithm was used to predict immune infiltration, the starBase database was used to screen the miRNA-mRNA regulatory axis, and immunohistochemical analyses were performed to verify protein expression.

RESULTS

GTP alleviated the deterioration of renal function, renal inflammation and fibrosis, and mitochondrial and endoplasmic reticulum lesions induced by DEHP in mice. Differential immune infiltrations of plasma, dendritic, T, and B cells were noted between the model and treatment groups. We found that three differentially expressed miRNAs (mmu-miR-383-5p, mmu-miR-152-3p, and mmu-miR-144-3p), three differentially expressed mRNAs (Ddit4, Dusp1, and Snx18), and three differentially expressed proteins (Ddit4, Dusp1, and Snx18) played crucial roles in the miRNA-mRNA-protein regulatory axes when GTPs mitigate DEHP-induced kidney damage in mice.

CONCLUSION

GTP can alleviate DEHP-induced kidney damage and regulate immune cell infiltration. We screened four important miRNA-mRNA-protein regulatory axes of GTP, mitigating DEHP-induced kidney damage in mice.

Mitochondrial disorder and treatment of ischemic cardiomyopathy: Potential and advantages of Chinese herbal medicine

Mitochondrial dysfunction is the main cause of damage to the pathological mechanism of ischemic cardiomyopathy. In addition, mitochondrial dysfunction can also affect the homeostasis of cardiomyocytes or endothelial cell dysfunction, leading to a vicious cycle of mitochondrial oxidative stress. And mitochondrial dysfunction is also an important pathological basis for ischemic cardiomyopathy and reperfusion injury after myocardial infarction or end-stage coronary heart disease. Therefore, mitochondria can be used as therapeutic targets against myocardial ischemia injury, and the regulation of mitochondrial morphology, function and structure is a key and important way of targeting mitochondrial quality control therapeutic mechanisms. Mitochondrial quality control includes mechanisms such as mitophagy, mitochondrial dynamics (mitochondrial fusion/fission), mitochondrial biosynthesis, and mitochondrial unfolded protein responses. Among them, the increase of mitochondrial fragmentation caused by mitochondrial pathological fission is the initial factor. The protective mitochondrial fusion can strengthen the interaction and synthesis of paired mitochondria and promote mitochondrial biosynthesis. In ischemia or hypoxia, pathological mitochondrial fission can promote the formation of mitochondrial fragments, fragmented mitochondria can lead to damaged mitochondrial DNA production, which can lead to mitochondrial biosynthesis dysfunction, insufficient mitochondrial ATP production, and mitochondrial ROS. Burst growth or loss of mitochondrial membrane potential. This eventually leads to the accumulation of damaged mitochondria. Then, under the leadership of mitophagy, damaged mitochondria can complete the mitochondrial degradation process through mitophagy, and transport the morphologically and structurally damaged mitochondria to lysosomes for degradation. But once the pathological mitochondrial fission increases, the damaged mitochondria increases, which may activate the pathway of cardiomyocyte death. Although laboratory studies have found that a variety of mitochondrial-targeted drugs can reduce myocardial ischemia and protect cardiomyocytes, there are still few drugs that have successfully passed clinical trials. In this review, we describe the role of MQS in ischemia/hypoxia-induced cardiomyocyte physiopathology and elucidate the relevant mechanisms of mitochondrial dysfunction in ischemic cardiomyopathy. In addition, we also further explained the advantages of natural products in improving mitochondrial dysfunction and protecting myocardial cells from the perspective of pharmacological mechanism, and explained its related mechanisms. Potential targeted therapies that can be used to improve MQS under ischemia/hypoxia are discussed, aiming to accelerate the development of cardioprotective drugs targeting mitochondrial dysfunction.

Molecular Epidemiology of Mitochondrial Cardiomyopathy: A Search Among Mitochondrial and Nuclear Genes

Mitochondrial Cardiomyopathy (MCM) is a common manifestation of multi-organ Mitochondrial Diseases (MDs), occasionally present in non-syndromic cases. Diagnosis of MCM is complex because of wide clinical and genetic heterogeneity and requires medical, laboratory, and neuroimaging investigations. Currently, the molecular screening for MCM is fundamental part of MDs management and allows achieving the definitive diagnosis. In this article, we review the current genetic knowledge associated with MDs, focusing on diagnosis of MCM and MDs showing cardiac involvement. We searched for publications on mitochondrial and nuclear genes involved in MCM, mainly focusing on genetic screening based on targeted gene panels for the molecular diagnosis of the MCM, by using Next Generation Sequencing. Here we report twelve case reports, four case-control studies, eleven retrospective studies, and two prospective studies, for a total of twenty-nine papers concerning the evaluation of cardiac manifestations in mitochondrial diseases. From the analysis of published causal mutations, we identified 130 genes to be associated with mitochondrial heart diseases. A large proportion of these genes (34.3%) encode for key proteins involved in the oxidative phosphorylation system (OXPHOS), either as directly OXPHOS subunits (22.8%), and as OXPHOS assembly factors (11.5%). Mutations in several mitochondrial tRNA genes have been also reported in multi-organ or isolated MCM (15.3%). This review highlights the main disease-genes, identified by extensive genetic analysis, which could be included as target genes in next generation panels for the molecular diagnosis of patients with clinical suspect of mitochondrial cardiomyopathies.

Novel mitochondrion-targeting copper(II) complex induces HK2 malfunction and inhibits glycolysis via Drp1-mediating mitophagy in HCC

[Cu(ttpy-tpp)Br₂ ]Br (abbreviated as CTB) is a novel mitochondrion-targeting copper(II) complex synthesized by our research group, which contains tri-phenyl-phosphonium (TPP) groups as its lipophilic property. In this study, we explored how CTB affects mitochondrial functions and exerts its anti-tumour activity. Multiple functional and molecular analyses including Seahorse XF Bioanalyzer Platform, Western blot, immunofluorescence analysis, co-immunoprecipitation and transmission electron microscopy were used to elucidate the underlying mechanisms. Human hepatoma cells were subcutaneously injected into right armpit of male nude mice for evaluating the effects of CTB in vivo. We discovered that CTB inhibited aerobic glycolysis and cell acidification by impairing the activity of HK2 in hepatoma cells, accompanied by dissociation of HK2 from mitochondria. The modification of HK2 not only led to the complete dissipation of mitochondrial membrane potential (MMP) but also promoted the opening of mitochondrial permeability transition pore (mPTP), contributing to the activation of mitophagy. In addition, CTB co-ordinately promoted dynamin-related protein 1 (Drp1) recruitment in mitochondria to induce mitochondrial fission. Our findings established a previously unrecognized role for copper complex in aerobic glycolysis of tumour cells, revealing the interaction between mitochondrial HK2-mediated mitophagy and Drp1-regulated mitochondrial fission.

Diabetic Pregnancy and Maternal High-Fat Diet Impair Mitochondrial Dynamism in the Developing Fetal Rat Heart by Sex-Specific Mechanisms

Infants born to diabetic or obese mothers are at greater risk of heart disease at birth and throughout life, but prevention is hindered because underlying mechanisms remain poorly understood. Using a rat model, we showed that prenatal exposure to maternal diabetes and a high-fat diet caused diastolic and systolic dysfunction, myocardial lipid accumulation, decreased respiratory capacity, and oxidative stress in newborn offspring hearts. This study aimed to determine whether mitochondrial dynamism played a role. Using confocal live-cell imaging, we examined mitochondrial dynamics in neonatal rat cardiomyocytes (NRCM) from four prenatally exposed groups: controls, diabetes, high-fat diet, and combination exposed. Cardiac expression of dynamism-related genes and proteins were compared, and gender-specific differences were evaluated. Findings show that normal NRCM have highly dynamic mitochondria with a well-balanced number of fusion and fission events. Prenatal exposure to diabetes or a high-fat diet impaired dynamism resulting in shorter, wider mitochondria. Mechanisms of impaired dynamism were gender-specific and protein regulated. Females had higher expression of fusion proteins which may confer a cardioprotective effect. Prenatally exposed male hearts had post-translational modifications known to impair dynamism and influence mitophagy-mediated cell death. This study identifies mitochondrial fusion and fission proteins as targetable, pathogenic regulators of heart health in offspring exposed to excess circulating maternal fuels.