Effects of NRF-1 and PGC-1α cooperation on HIF-1α and rat cardiomyocyte apoptosis under hypoxia

Natural products alleviate atrial fibrillation by modulating mitochondrial quality control

BACKGROUND

Atrial fibrillation (AF), one of the most common cardiac arrhythmias, is associated with high mortality rates and significant healthcare burdens. Mitochondrial homeostasis has recently emerged as a critical factor in AF pathogenesis but remains at the experimental stage. Current drug and surgical treatments for AF often involve side effects and require ongoing treatment plan evaluation and adjustment. In contrast, natural products (NPs), which have been utilized in China for over 2,000 years, show remarkable efficacy in treating AF and are receiving growing attention.

PURPOSE

We aimed to investigate the regulatory effects of NPs on mitochondrial quality control (MQC) and their impact on AF occurrence and progression. By constructing a novel NP-mitochondria-AF axis, we propose a framework to translate experimental findings into clinical practice and identify potential therapeutic strategies for AF.

METHODS

Databases such as PubMed, Web of Science, and China National Knowledge Infrastructure were searched (up to October 2024) using the following keywords: "atrial fibrillation," "traditional Chinese medicine," "mitochondrial biogenesis," "mitochondrial dynamics," "mitophagy," "apoptosis," "oxidative stress," "inflammation," and "Ca2+ concentration." NP targets were identified using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, while disease targets were retrieved from Online Mendelian Inheritance in Man, GeneCards, and Therapeutic Target Database. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed using the Metascape database. Protein-protein interactions were analyzed using the STRING database, and core monomers and hub genes were identified using Cytoscape 3.7.2.

RESULTS

We found a strong relationship between mitochondrial homeostasis and AF development. KEGG pathway analysis indicated that commonly used NPs regulate mitochondrial homeostasis, affecting AF progression through various hub genes, including protein kinase B-alpha (AKT1), jun proto-oncogene (JUN), and tumor necrosis factor (TNF). Molecular docking analysis revealed that NP core monomers exhibited binding affinities to hub genes below -5 kcal/mol and to transforming growth factor-β (TGF-β) below -7 kcal/mol.

CONCLUSION

NPs, including traditional Chinese medicine (TCM) compounds, TCM monomers, and traditional Chinese patent medicines, alleviate AF by modulating MQC with minimal side effects and high efficacy. These findings highlight the therapeutic potential of NPs as promising candidates for AF treatment and further underscore the importance of MQC in AF pathogenesis.

Predictive value of HIF-1α for left ventricular remodeling following an anterior ST-segment elevation myocardial infarction

BACKGROUND

Hypoxia-inducible factor-1α (HIF-1α) has an essential role in ventricular remodeling processes involving myocardial fibrosis and hypertrophy, but the clinical significance of HIF-1α levels in the early period after ST-segment elevation myocardial infarction (STEMI) for the prediction of left ventricular remodeling (LVR) has yet to be fully elucidated.

OBJECTIVE

To investigate the predictive value of HIF-1α for LVR after STEMI based on the echocardiographic parameters.

METHODS

In this prospective observational study, plasma samples were collected within 12 hours of onset from 183 patients with a first reperfused anterior ST-segment elevation myocardial infarction (STEMI), and HIF-1α levels were measured using enzyme-linked immunosorbent assay (ELISA). At baseline and 12 months after discharge, all patients underwent repeat echocardiography. The changes of echocardiography parameters from baseline to 12 months were used to reflect the changes of ventricular structure and function. An increase in end-diastolic volume of ≥20 % was defined as LVR.

RESULTS

The levels of HIF-1α were highly correlated with the changes of echocardiography parameters (ΔLVEF, ΔLVEDD, as well as ΔLVEDV). During the follow-up period, patients with higher HIF-1α concentrations had higher incidence of LVR, poorer ventricular function, and a lower MACE-free survival. Multivariate analysis showed the single-point HIF-1α was an independent predictor of LVR (odds ratio[OR]: 4.813; 95 % CI: 1.553 to 14.918; P = 0.006). The HIF-1α levels predicted LVR with an AUC of 0.7905 (95 % CI: 0.7067 to 0.8744; P < 0.0001). The combination of HIF-1α and N-terminal probrain natriuretic peptide (NT-proBNP) yielded a favorable increase in AUC to 0.8121 (95 % CI: 0.7345 to 0.8896; P < 0.0001).

CONCLUSION

These results demonstrate that serum HIF-1α levels can predict LVR after STEMI independently.

NRF-1 promotes FUNDC1-mediated mitophagy as a protective mechanism against hypoxia-induced injury in cardiomyocytes

Hypoxia-induced apoptosis and mitochondrial dysfunction in cardiomyocytes are involved in the mechanisms of heart failure. Our previous studies have confirmed that NRF-1 alleviates hypoxia-induced injury by promoting mitochondrial function and inhibiting apoptosis in cardiomyocytes. However, the mechanism by which NRF-1 attenuates hypoxia-induced injury in cardiomyocytes is still unclear. Mitophagy, a selective autophagy, has recently shown a remarkable correlation with hypoxia-induced cardiomyocyte injury. In this study, we evaluated whether NRF-1 protects cardiomyocytes from hypoxia-induced injury by regulating mitophagy. The findings indicate that hypoxia prevents H9c2 cells from growing, encourages mitochondrial dysfunction, and triggers mitophagy. In addition, promoting mitophagy by rapamycin reduces hypoxia-induced injury in H9c2 cells. Overexpression of NRF-1 in hypoxia-induced H9c2 cells promotes mitophagy and alleviates cell injury, and this effect can be inhibited by 3-MA. Further study found that NRF-1 promotes the expression of FUNDC1 by binding to its promoter region. Knockdown of FUNDC1 in NRF-1 over-expression H9c2 cells inhibited mitophagy and aggravated hypoxia-induced injury. In conclusion, our study suggests that NRF-1 protects against hypoxia-induced injury by regulating FUNDC1-mediated mitophagy in cardiomyocytes.

Transcriptome and chromatin accessibility landscape of ovarian development at different egg-laying stages in taihe black-bone silky fowls

Taihe Black-Bone Silky Fowl (SF) is a famous local breed in China, known for its high nutritional and medicinal value. However, its low egg-laying rate significantly limits its economic benefits. This study aims to explore the ovarian development status, as well as the changes in the transcriptome and chromatin accessibility landscape at different egg-laying stages of SF, in order to reveal the epigenetic regulatory mechanisms underlying ovarian development in laying hens. The results showed that during peak egg-laying, serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and progesterone (P4) in the SF were higher than in the other laying periods. Meanwhile, the serum and ovarian matrix total antioxidant capacity (T-AOC) level decreased with increasing age, whereas the ovarian matrix malondialdehyde (MDA) level showed the opposite trend. Compared to the late laying period, several genes related to ovarian development and reproductive hormone secretion, including TDRD5, CCNO, CYP17A1, BMP15, and STAR, were upregulated during the peak egg-laying period. Additionally, we identified key transcription factors (TF) associated with different egg-laying periods. Specific TF, such as Fli1, Etv2, and AT2G15740, linked to the peak egg-laying period, play significant roles in cell and tissue development. The specific transcription factor Nr5a2, associated with the late laying period, has been shown to inhibit E2 production. Furthermore, genes related to poultry reproductive performance, such as STAR and WNT4, were found to be regulated by specific distal enhancers in open chromatin regions (OCR). In conclusion, this study elucidated the dynamic changes in the transcriptome and chromatin accessibility landscape during ovarian development in SF at different egg-laying stages and highlighted key TF, including Fli1, Etv2, and Nr5a2, as well as essential genes like STAR and WNT4 that regulate ovarian development. These findings provide valuable insights into the regulatory mechanisms influencing egg-laying performance in SF and offer new strategies for improving ovarian follicle development and egg production performance in poultry.

MicroRNA-specific therapeutic targets and biomarkers of apoptosis following myocardial ischemia-reperfusion injury

MicroRNAs are single-stranded non-coding RNAs that participate in post-transcriptional regulation of gene expression, it is involved in the regulation of apoptosis after myocardial ischemia-reperfusion injury. For example, the alteration of mitochondrial structure is facilitated by MicroRNA-1 through the regulation of apoptosis-related proteins, such as Bax and Bcl-2, thereby mitigating cardiomyocyte apoptosis. MicroRNA-21 not only modulates the expression of NF-κB to suppress inflammatory signals but also activates the PI3K/AKT pathway to mitigate ischemia-reperfusion injury. Overexpression of MicroRNA-133 attenuates reactive oxygen species (ROS) production and suppressed the oxidative stress response, thereby mitigating cellular apoptosis. MicroRNA-139 modulates the extrinsic death signal of Fas, while MicroRNA-145 regulates endoplasmic reticulum calcium overload, both of which exert regulatory effects on cardiomyocyte apoptosis. Therefore, the article categorizes the molecular mechanisms based on the three classical pathways and multiple signaling pathways of apoptosis. It summarizes the targets and pathways of MicroRNA therapy for ischemia-reperfusion injury and analyzes future research directions.

The possible protective effect of l-cysteine in a rat model of sciatic nerve ischemia-reperfusion: A possible role for NRF1 and Caspase 3; Biochemical, Histological, and Immunohistochemical study

Organ damage brought on by ischemia is exacerbated by the reperfusion process. L-cysteine is a semi-essential amino acid that acts as a substrate for cystathionine-β-synthase in the central nervous system. The aim of this study was to investigate the possible protective effects of L- cysteine against the structural and biochemical changes that occur in the rat sciatic nerve after ischemia reperfusion (I/R) and to address some of the underlying mechanisms of these effects. Rats were divided into 4 groups: sham, l-cysteine, I/R, and l-cysteine- I/R groups. Specimens of sciatic nerve were processed for biochemical, histological, and immunohistochemical assessment. The results showed in I/R group, a significant increase in malondialdehyde with a significant decrease in both Nuclear respiratory factor-1 (NRF1) and superoxide dismutase levels. Moreover, with histological alteration. There was a significant increase in the mean surface area fraction of anti-caspase immunopositive cells as well as a significantdecrease in mean surface area fraction of anti-CD 34 immunopositive cells. In contrast, the l-cysteine- I/R group showed amelioration of these biochemical, structural, and immunohistochemical changes. To the best of our knowledge, this is the first study showed the protective effects of l-cysteine in sciatic nerve I/R via NRF1and caspase 3 modulation as well as telocyte activation.

Role of ATG7-dependent non-autophagic pathway in angiogenesis

ATG7, one of the core proteins of autophagy, plays an important role in various biological processes, including the regulation of autophagy. While clear that autophagy drives angiogenesis, the role of ATG7 in angiogenesis remains less defined. Several studies have linked ATG7 with angiogenesis, which has long been underappreciated. The knockdown of ATG7 gene in cerebrovascular development leads to angiogenesis defects. In addition, specific knockout of ATG7 in endothelial cells results in abnormal development of neovascularization. Notably, the autophagy pathway is not necessary for ATG7 regulation of angiogenesis, while the ATG7-dependent non-autophagic pathway plays a critical role in the regulation of neovascularization. In order to gain a better understanding of the non-autophagic pathway-mediated biological functions of the autophagy-associated protein ATG7 and to bring attention to this expanding but understudied research area, this article reviews recent developments in the ATG7-dependent non-autophagic pathways regulating angiogenesis.

Fenofibrate alleviates NAFLD by enhancing the PPARα/PGC-1α signaling pathway coupling mitochondrial function

BACKGROUND

To comprehend the influences of fenofibrate on hepatic lipid accumulation and mitochondrial function-related signaling pathways in mice with non-alcoholic fatty liver disease (NAFLD) secondary to high-fat diets together with free fatty acids-influenced HepG2 cells model.

MATERIALS AND METHODS

A random allocation of male 6-week C57BL/6J mice into three groups was done, including controls, model (14 weeks of a high-fat diet), and fenofibrate [similar to the model one with administered 0.04 g/(kg.d) fenofibrate by gavage at 11 weeks for 4 weeks] groups, which contained 10 mice each. This study verified NAFLD pathogenesis via mitochondrial functions in hepatic pathological abnormalities, liver index and weight, body weight, serum biochemical indexes, oxidative stress indicators, mitochondrial function indexes, and related signaling pathways. The effect of fenofibrate intervention was investigated in NAFLD model mice. In vitro, four groups based on HepG2 cells were generated, including controls, the FFA model (1.5 mmol/L FFA incubation for 24 h), LV-PGC-1α intervention (similar to the FFA model one after PPARGC1A lentivirus transfection), and LV control intervention (similar to the FFA model one after negative control lentivirus transfection) groups. The study investigated the mechanism of PGC-1α related to lipid decomposition and mitochondrial biosynthesis by Oil red O staining, colorimetry and western blot.

RESULTS

In vivo experiments, a high-fat diet achieved remarkable changes regarding liver weight, liver index, serum biochemical indicators, oxidative stress indicators, liver pathological changes, mitochondrial function indicators, and body weight of the NAFLD model mice while fenofibrate improved the objective indicators. In the HepG2 cells model, the lipid accumulation increased significantly within the FFA model group, together with aggravated hepatocytic damage and boosted oxidative stress levels. Moreover, FFA induced excessive mitosis into fragmented in mitochondrial morphology, ATP content in cells decreased, mtDNA replication fold decreased, the expression of lipid decomposition protein PPARα reduced, mitochondrial biosynthesis related protein PGC-1α, NRF-1 and TFAM decreased. PGC-1α overexpression inhibited lipid deposition by improving mitochondrial biosynthesis and lipid decomposition.

CONCLUSION

Fenofibrate up-regulated PPARα/PGC-1α signaling pathway, promoted mitochondrial β-oxidation, reduced oxidative stress damage and lipid accumulation of liver. PGC-1α overexpression enhanced mitochondrial biosynthesis and ATP production, and reduced HepG2 intracellular accumulation of lipids and oxidative stress.

The rs17782313 polymorphism near MC4R gene confers a high risk of obesity and hyperglycemia, while PGC1α rs8192678 polymorphism is weakly correlated with glucometabolic disorder: a systematic review and meta-analysis

Background

The relationships of the rs17782313 polymorphism near melanocortin 4 receptor gene (MC4R) and the rs8192678 polymorphism in peroxisome proliferator-activated receptor gamma coactivator 1 alpha gene (PGC1α) with metabolic abnormalities have been explored in many populations around the world, but the findings were not all consistent and sometimes even a bit contradictory.

Methods

Electronic databases including Medline, Scopus, Embase, Web of Science, CNKI and Google Scholar were checked for studies that met the inclusion criteria. Data were carefully extracted from eligible studies. Standardized mean differences (SMDs) were calculated by using a random-effects model to examine the differences in the indexes of obesity, glucometabolic disorder and dyslipidemia between the genotypes of the rs17782313 and rs8192678 polymorphisms. Cochran's Q-statistic test and Begg's test were employed to identify heterogeneity among studies and publication bias, respectively.

Results

Fifty studies (58,716 subjects) and 51 studies (18,660 subjects) were respectively included in the pooled meta-analyses for the rs17782313 and rs8192678 polymorphisms. The C-allele carriers of the rs17782313 polymorphism had a higher average level of body mass index (SMD = 0.21 kg/m2, 95% confidence interval [95% CI] = 0.12 to 0.29 kg/m2, p < 0.001), waist circumference (SMD = 0.14 cm, 95% CI = 0.06 to 0.23 cm, p < 0.001) and blood glucose (SMD = 0.09 mg/dL, 95% CI = 0.02 to 0.16 mg/dL, p = 0.01) than the TT homozygotes. Regarding the rs8192678 polymorphism, no significant associations with the indexes of obesity, glucometabolic disorder and dyslipidemia were detected. However, significant correlations between the rs8192678 polymorphism and multiple glucometabolic indexes were observed in subgroup analyses stratified by sex, age, ethnicity and health status.

Conclusion

The meta-analysis demonstrates that the C allele of the MC4R rs17782313 polymorphism confers a higher risk of obesity and hyperglycemia, and the PGC1α rs8192678 polymorphism is weakly correlated with glucometabolic disorder. These findings may partly explain the relationships between these variants and diabetes as well as cardiovascular disease.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022373543.

Roles of the HIF-1α pathway in the development and progression of keloids

Keloids, a pathological scar that is induced by the consequence of aberrant wound healing, is still a major global health concern for its unsatisfactory treatment outcomes. HIF-1α, a main regulator of hypoxia, mainly acts through some proteins or signaling pathways and plays important roles in a variety of biological processes. Accumulating evidence has shown that HIF-1α played a crucial role in the process of keloid formation. In this review, we attempted to summarize the current knowledge on the association between HIF-1α expression and the development and progression of keloids. Through a comprehensive analysis, the molecular mechanisms underlying HIF-1α in keloids were shown to be correlated to the proliferation of fibroblasts, angiogenesis, and collagen deposits. The affected proteins and the signaling pathways were multiple. For instance, HIF-1α was reported to promote keloids formation by enhancing angiogenesis, fibroblast proliferation, and collagen deposition through the activation of periostin PI3K/Akt, TGF-β/Smad and TLR4/MyD88/NF-κB pathway. However, the specific effects of HIF-1α on keloids keloid illnesses in clinical practice is are entirely unclear, and further studies in clinical trials are still warranted. Therefore, an in-depth understanding of the biological mechanisms of HIF-1α in keloid formation is significant to develop promising therapeutic targets for the treatment of keloids in clinical practice.

The protective effect of resveratrol on largemouth bass (Micropterus salmoides) during out-of-season spawning

In aquaculture production, out-of-season spawning is beneficial to solve the seasonal shortage of fry that are normally produced once annually by species such as largemouth bass (Micropterus salmoides), thereby implementing year-round fry production. Maintaining low temperature over a period of several months can delay largemouth bass ovarian development, but it can cause severe stress to their reproductive function, leading to decreased fertility during out-of-season spawning. Feeding with antioxidants is one of the most effective methods to alleviate the negative effects of low temperature stress. Therefore, the purpose of this study is to: (a) evaluate the changes in oocyte morphology, antioxidant capacity, reproductive hormone-related index, cell apoptosis and autophagy during the out-of-season spawning of largemouth bass, and (b) to investigate the protective effect of the antioxidant resveratrol on this fish during out-of-season spawning from May through August. The study was divided into two groups (three replicates per group, 2000 fish per replicate): control group (Control) (exposure to water temperature of 12-17 °C) and resveratrol supplementation group (Res) (exposure to water temperature of 12-17 °C and fed with 200 mg/kg resveratrol). The results show that: (1) The serum hormones LH and E2 increased first and then remained unchanged, and the ovarian section showed that the ovary remained in stage IV. (2) In the process of off-season reproduction, a large number of follicles experienced follicular atresia, accompanied by endoplasmic reticulum expansion, nuclear chromatin condensation and mitochondrial swelling, which was relieved after feeding resveratrol. (3) Resveratrol decreased the ovarian ROS content and improved the activities of CAT and other antioxidant enzymes in the ovary and liver to some extent. (4) Resveratrol reduced the level of pro-apoptotic (Bax, Caspase3, Caspase8, Caspase9) and autophagy-related components (LC3-B, Beclin-1) while increasing the transcription level of anti-apoptotic (Bcl-2) factors. These findings suggest that resveratrol alleviates some adverse effects of largemouth bass during out-of-season spawning to some extent and provide a model for efficient and high-quality out-of-season spawning.