Akap1 deficiency exacerbates diabetic cardiomyopathy in mice by NDUFS1-mediated mitochondrial dysfunction and apoptosis

Molecular Alterations in Core Subunits of Mitochondrial Complex I and Their Relation to Parkinson's Disease

Among the myriad of neurodegenerative diseases, mitochondrial dysfunction represents a nexus regarding their pathogenic processes, in which Parkinson's disease (PD) is notable for inherent vulnerability of the dopaminergic pathway to energy deficits and oxidative stress. Underlying this dysfunction, the occurrence of defects in complex I (CI) derived from molecular alterations in its subunits has been described in the literature. However, the mechanistic understanding of the processes mediating the occurrence of mitochondrial dysfunction mediated by CI deficiency in PD remains uncertain and subject to some inconsistencies. Therefore, this review analyzed existing evidence that may explain the relationship between molecular alterations in the core subunits of CI, recognized for their direct contribution to its enzymatic performance, and the pathogenesis of PD. As a result, we discussed 47 genetic variants in the 14 core subunits of CI, which, despite some discordant results, were predominantly associated with varying degrees of deficiency in complex enzymatic activity, as well as defects in supercomplex biogenesis and CI itself. Finally, we hypothesized about the relationship of the described alterations with the pathogenesis of PD and offered some suggestions that may aid in the design of future studies aimed at elucidating the relationship between such alterations and PD.

The role of the farnesoid X receptor in diabetes and its complications

Diabetes is a metabolic disease in which tissues and organs are exposed to a hyperglycemic environment for a prolonged period. Long-term hyperglycemia can cause dysfunction of multiple organs and tissues in the body, leading to diabetic complications such as diabetic cardiomyopathy and diabetic nephropathy. Diabetes and its complications have become one of the key issues that seriously threaten the health of people worldwide. Farnesoid X receptor (FXR), as a metabolic regulator, has multiple functions in regulating insulin synthesis and secretion, insulin resistance, lipid metabolism, oxidative stress, inflammatory response, and fibrosis. It plays a key role in alleviating diabetes and its complications. In this review, we discuss the latest findings of FXR related to diabetes and its complications, focusing on its role in diabetes, diabetic nephropathy, diabetic cardiomyopathy, and diabetic liver injury. The aim is to better understand the role of FXR in diabetes and its complications and to provide new perspectives on the treatment of diabetes and its complications.

AKAP1-STABILIZED TIMP-4 ATTENUATES ANG-II-INDUCED OXIDATIVE STRESS AND INFLAMMATION IN VASCULAR SMOOTH MUSCLE CELLS BY INACTIVATING THE NF-ΚB SIGNALING

ABSTRACT

Background: Oxidative stress and inflammation are key factors contributing to the complex pathogenesis of abdominal aortic aneurysm (AAA). Tissue inhibitor of metalloproteinases-4 (TIMP-4) expression is reduced in AAA patients. In this study, we investigated the impact of TIMP-4 on the phenotype alterations induced by angiotensin II (Ang-II) in human vascular smooth muscle cells (VSMCs). Methods: The expression profiling of TIMP-4 and A-kinase anchoring protein (AKAP1) in AAA samples was analyzed using the GSE7084 and GSE140947 datasets. Levels of TIMP-4 and AKAP1 in Ang-II-exposed VSMCs and AAA tissues and serum samples were detected. RNA immunoprecipitation (RIP) experiment and mRNA stability analysis were used to examine the interaction between AKAP1 and TIMP-4 mRNA. The impact of the AKAP1/TIMP-4 cascade on Ang-II-induced VSMC phenotype alterations was determined by evaluating cell viability, apoptosis, oxidative stress, and inflammation. Results: TIMP-4 and AKAP1 levels were decreased in Ang-II-exposed VSMCs. Increased TIMP-4 expression protected VSMCs against Ang-II-evoked growth impairment in vitro . Moreover, TIMP-4 upregulation diminished Ang-II-evoked oxidative stress and inflammation in VSMCs. Mechanistically, RNA binding protein (RBP) AKAP1 stabilized TIMP-4 mRNA to elevate TIMP-4 expression. TIMP-4 reduction partially abrogated AKAP1-driven suppression on oxidative stress, inflammation, matrix metalloproteinase (MMP9) expression, and nuclear factor kappa B (NF-κB) pathway activation in Ang-II-exposed VSMCs. Additionally, TIMP-4 and AKAP1 levels were downregulated in AAA patients in their AAA tissues and serum samples. TIMP-4 and AKAP1 had good diagnostic values for AAA with high area under the ROC curve. Conclusion: Our study provides evidence for the role of the AKAP1/TIMP-4/NF-κB pathway in Ang-II-induced VSMC inflammation and oxidative stress.

l-Arginine: A multifaceted regulator of diabetic cardiomyopathy

In diabetes mellitus, dysregulated glucose and lipid metabolism lead to diabetic cardiomyopathy (DCM) by imparting pathological myocardial remodeling and cellular injury. Accelerated glycation, oxidative stress, and activated inflammatory pathways culminate in cardiac fibrosis and hypertrophy in DCM. The regulatory effects of l-Arginine (L-Arg) have been elucidated in the pathological changes of DCM, including myocardial fibrosis, hypertrophy, and apoptosis, by inhibiting glycation and oxidative stress-induced inflammation. Disturbed L-Arg metabolism and decreased intracellular L-Arg pool are correlated with the progression of DCM; therefore, L-Arg supplementation has been prescribed for various cardiovascular dysfunctions. This review expands the therapeutic potential of L-Arg supplementation in DCM by elucidating its molecular mechanism of action and exploring potential clinical outcomes.

Sotorasib-impaired degradation of NEU1 contributes to cardiac injury by inhibiting AKT signaling

Sotorasib, the inaugural targeted inhibitor sanctioned for the management of patients afflicted with locally advanced or metastatic non-small cell lung cancer presenting the KRAS G12C mutation, has encountered clinical application constraints due to its potential for cardiac injury as evidenced by safety trials. This investigation has elucidated that the heightened expression of neuraminidase-1 (NEU1) constitutes the principal etiology of cardiac damage induced by sotorasib. Mechanistically, sotorasib treatment inhibited the ubiquitinated degradation of NEU1, leading to its elevated expression, which induced downstream AKT signaling pathway inhibition and mitochondrial dysfunction leading to cardiomyocyte apoptosis. Meanwhile, in vivo and in vitro studies showed that D-pantothenic acid (D-PAC) alleviated sotorasib-induced cardiac damage by promoting NEU1 degradation. In conclusion, this study revealed that NEU1 is a key protein in sotorasib cardiotoxicity and that reducing the level of this protein is a critical strategy for the clinical treatment of sotorasib-induced cardiac injury. Schematic representation of a mechanism.

Perillaldehyde targeting PARP1 to inhibit TRPM2-CaMKII/CaN signal transduction in diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DC) is a serious complication of diabetes, characterized by myocardial fibrosis, hypertrophy, oxidative stress, and inflammation. Perillaldehyde (PAE), a natural monoterpene, has shown potential in mitigating cardiac damage.

PURPOSE

This study aims to elucidate the molecular mechanism of the protective effect of PAE on the DC and the interaction between DC pathogenesis.

METHODS

Network pharmacology and molecular docking were used to identify PARP1 as a core target for PAE in DC. Animal experiments involved intervening DC mice with PAE and assessing cardiac function, oxidative stress, and apoptosis. In vitro, high glucose-induced H9c2 cells were used to validate PAE's effects on cell viability and protein expression.

RESULTS

The results showed that PAE improved the general condition of DC mice, reduced cardiac injury and cardiac insufficiency, decreased myocardial mitochondrial damage, and reduced apoptosis. In addition, PAE upregulated the expression of Bcl-2, downregulated Bax protein expression, inhibited Caspase-3 activity, and inhibited the expression of PARP1, TRPM2, CaN, and CaMKII proteins in DC mice and high glucose-induced H9c2 cells.

CONCLUSION

Mechanically, this study clarified that PAE's inhibition of the PARP1-TRPM2-CaMKII/CaN pathway reduces calcium-activated mitochondrial damage, apoptosis, and oxidative stress in diabetic cardiomyopathy. This discovery provides an innovative therapeutic strategy for DC and an experimental foundation for PAE's drug development, with significant practical implications.

A-kinase anchoring protein 1: an independent predictor of coronary artery disease

INTRODUCTION

Coronary artery disease (CAD) is the leading cause of death worldwide. A-kinase anchoring protein 1 (AKAP1), thought to regulate the function and structure of mitochondria, is enriched in the heart, where it plays a protective role. However, data on the serum AKAP1 concentration levels in patients with CAD are currently lacking. To address this, the serum levels of AKAP1 in patients with CAD were quantified and their predictive ability for CAD was evaluated in this study.

METHODS

A total of 255 patients referred for coronary angiography were included in this study and classified into two groups (CAD and non-CAD group). A comparative analysis of clinical data and serum AKAP1 concentration levels was performed between the two groups. The patients were then divided into quartiles according to AKAP1 levels. A multivariate logistic regression model was used to assess the independent association of AKAP1 with CAD.

RESULTS

The CAD group showed a lower AKAP1 concentration than the non-CAD group (P < 0.01). The AKAP1 level was correlated with a history of CAD (P < 0.001). The receiver operator characteristic (ROC) curve analysis showed a low ability of AKAP1 in predicting CAD (area under the ROC curve = 0.649). Finally, in the multivariate logistic regression model with the highest quartile as the reference, the lowest quartile of AKAP1 remained significantly associated with an increased risk for CAD (odds ratio (OR) = 5.677, 95% confidence interval [CI] 1.704 to 18.912, P = 0.005).

CONCLUSIONS

Our results confirmed that serum AKAP1 levels are inversely associated with CAD and may therefore be used as a marker for CAD prediction. But additional studies are needed to confirm and further elucidate our results.

Identifying disulfidptosis-related biomarkers in epilepsy based on integrated bioinformatics and experimental analyses

One of the underlying mechanisms of epilepsy (EP), a brain disease characterized by recurrent seizures, is considered to be cell death. Disulfidptosis, a proposed novel cell death mechanism, is thought to play a part in the pathogenesis of epilepsy, but the exact role is unclear. The gene expression omnibus series (GSE) 33000 and GSE63808 datasets were used to search for differentially expressed disulfidptosis-related molecules (DE-DRMs). A correlation between the DE-DRMs was discovered. Individuals with epilepsy were then used to investigate molecular clusters based on the expression of DE-DRMs. Following that, the best machine learning model which is validated by GSE143272 dataset and predictor molecules were identified. The correlation between predictive molecules and clinical traits was determined. Based on the in vitro and in vivo seizures models, experimental analyses were applied to verify the DE-DRMs expressions and the correlation between them. Nine molecules were identified as DE-DRMs: glycogen synthase 1 (GYS1), solute carrier family 3 member 2 (SLC3A2), solute carrier family 7 member 11 (SLC7A11), NADH:ubiquinone oxidoreductase core subunit S1 (NDUFS1), 3-oxoacyl-ACP synthase, mitochondrial (OXSM), leucine rich pentatricopeptide repeat containing (LRPPRC), NADH:ubiquinone oxidoreductase subunit A11 (NDUFA11), NUBP iron‑sulfur cluster assembly factor, mitochondrial (NUBPL), and NCK associated protein 1 (NCKAP1). NDUFS1 interacted with NDUFA11, NUBPL, and LRPPRC, while SLC3A2 interacted with SLC7A11. The optimal machine learning model was revealed to be the random forest (RF) model. G protein guanine nucleotide-binding protein alpha subunit q (GNAQ) was linked to sodium valproate resistance. The experimental analyses suggested an upregulated SLC7A11 expression, an increased number of formed SLC3A2 and SLC7A11 complexes, and a decreased number of formed NDUFS1 and NDUFA11 complexes. This study provides previously undocumented evidence of the relationship between disulfidptosis and EP. In addition to suggesting that SLC7A11 may be a specific DRM for EP, this research demonstrates the alterations in two disulfidptosis-related protein complexes: SLC7A11-SLC3A2 and NDUFS1-NDUFA11.

Mitochondrial complex-1 as a therapeutic target for cardiac diseases

Mitochondrial dysfunction is critical for the development and progression of cardiovascular diseases (CVDs). Complex-1 (CI) is an essential component of the mitochondrial electron transport chain that participates in oxidative phosphorylation and energy production. CI is the largest multisubunit complex (~ 1 Mda) and comprises 45 protein subunits encoded by seven mt-DNA genes and 38 nuclear genes. These subunits function as the enzyme nicotinamide adenine dinucleotide  hydrogen (NADH): ubiquinone oxidoreductase. CI dysregulation has been implicated in various CVDs, including heart failure, ischemic heart disease, pressure overload, hypertrophy, and cardiomyopathy. Several studies demonstrated that impaired CI function contributes to increased oxidative stress, altered calcium homeostasis, and mitochondrial DNA damage in cardiac cells, leading to cardiomyocyte dysfunction and apoptosis. CI dysfunction has been associated with endothelial dysfunction, inflammation, and vascular remodeling, critical processes in developing atherosclerosis and hypertension. Although CI is crucial in physiological and pathological conditions, no potential therapeutics targeting CI are available to treat CVDs. We believe that a lack of understanding of CI's precise mechanisms and contributions to CVDs limits the development of therapeutic strategies. In this review, we comprehensively analyze the role of CI in cardiovascular health and disease to shed light on its potential therapeutic target role in CVDs.

ERK1/2 Inhibition Alleviates Diabetic Cardiomyopathy by Suppressing Fatty Acid Metabolism

BACKGROUND

Diabetes mellitus is associated with morphological and functional impairment of the heart primarily due to lipid toxicity caused by increased fatty acid metabolism. Extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) have been implicated in the metabolism of fatty acids in the liver and skeletal muscles. However, their role in the heart in diabetes remains unclear. In this study, we tested our hypothesis that pharmacological inhibition of ERK1/2 alleviates cardiac remodeling in diabetic mice through a reduction in fatty acid metabolism.

METHODS

ERK1/2 phosphorylation in diabetes was determined both in vitro and in vivo. H9C2 cells were subjected to high glucose, high palmitic acid, or both high glucose and palmitic acid. db/db and streptozotocin (STZ)-induced diabetic mice were analyzed for ERK1/2 phosphorylation levels as well as the effects of U0126 treatment on cardiac remodeling. Administration of STZ and U0126 in mice was performed via intraperitoneal injection. Blood glucose levels in mice were measured using a glucometer. Mouse heart total RNAs were purified for reverse transcription. Real-time polymerase chain reaction (PCR) analysis of the messenger ribonucleic acid (mRNA) expression was performed for hypertrophy (ANF, BNP, and βMHC), fibrosis (Col3α1), and fatty acid metabolism genes (PPARα, CPT1A, and FACS). Interstitial fibrosis of the myocardium was analyzed using Masson's trichrome staining of the paraffin-embedded tissues.

RESULTS

ERK1/2 phosphorylation was significantly increased in diabetic conditions. Inhibition of ERK1/2 by U0126 in both streptozotocin-induced diabetic mice and db/db mice resulted in a significant reduction in the expression of genes associated with hypertrophy and fibrosis. In contrast, elevated phosphorylation of ERK1/2 in Dusp6/8 knockout (DKO) mice resulted in fibrosis. Mechanistically, ERK1/2 activation enhanced the expression of fatty acid metabolism genes PPARα, CPT1A, and FACS in the heart, which was reversed by U0126 treatment.

CONCLUSION

ERK1/2 are potential therapeutic targets for diabetic cardiomyopathy by modulating fatty acid metabolism in the heart.

Aberrant STING activation promotes macrophage senescence by suppressing autophagy in vascular aging from diabetes

Diabetic vascular aging is driven by macrophage senescence, which propagates senescence-associated secretory phenotypes (SASP), exacerbating vascular dysfunction. This study utilized a type 2 diabetes mellitus (T2DM) mouse model induced by streptozotocin injection and a high-fat diet to investigate the role of STING in macrophage senescence. Vascular aging markers and senescent macrophages were assessed in vivo, while in vitro, high glucose treatment induced macrophage senescence, enhancing senescence in co-cultured vascular smooth muscle cells. Mechanistic studies revealed that STING activation inhibits autophagy by phosphorylating ULK1 at S757, accelerating senescence. Pharmacological modulation showed that the STING inhibitor H-151 alleviates, while the agonist DMXAA enhances, senescence. These findings highlight the STING-autophagy axis as a critical driver of macrophage senescence, offering insights into the molecular mechanisms of diabetic vascular aging and identifying potential therapeutic targets to mitigate vascular complications in diabetes.

NDUFA11 may be the disulfidptosis-related biomarker of ischemic stroke based on integrated bioinformatics, clinical samples, and experimental analyses

Background

Programmed cell death plays an important role in neuronal injury and death after ischemic stroke (IS), leading to cellular glucose deficiency. Glucose deficiency can cause abnormal accumulation of cytotoxic disulfides, resulting in disulfidptosis. Ferroptosis, apoptosis, necroptosis, and autophagy inhibitors cannot inhibit this novel programmed cell death mechanism. Nevertheless, the potential mechanisms of disulfidptosis in IS remain unclear.

Methods

The GSE16561 dataset was used to screen for differentially expressed disulfidptosis-related biomarkers (DE-DRBs). A correlation between the DE-DRBs was detected. The optimal machine-learning (ML) model and predictor molecules were determined. The GSE58294 dataset was used to verify the accuracy of the optimal ML model. The DE-DRB expression was detected in the blood of patients with IS. Based on IS models, experimental analyses were performed to verify DE-DRB expression and the correlation between DE-DRBs.

Results

Leucine-rich pentatricopeptide repeat-containing (LRPPRC) and NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 11 (NDUFA11) were identified as DE-DRBs. The NADH: ubiquinone oxidoreductase core subunit S1 (NDUFS1) interacted with NDUFA11 and LRPPRC. The support vector machine (SVM) model was identified as the optimal ML model. The NDUFA11 expression level in the blood of patients with IS was 20.9% compared to that in normal controls. NDUFA11 expression was downregulated in the in vitro/in vivo models of IS. The number of formed complexes of NDUFS1 and NDUFA11 decreased in the in vitro/in vivo models of IS.

Conclusion

This research suggests that NDUFA11 is a specific DRB for IS and demonstrates alterations in the disulfidptosis-related protein complexes NDUFS1-NDUFA11.

NDUFS3 alleviates oxidative stress and ferroptosis in sepsis induced acute kidney injury through AMPK pathway

In recent years, ferroptosis has been found to play an important role in various acute kidney injury (AKI). However, relatively little research has been conducted on sepsis-induced acute kidney injury (SI-AKI). As an important trigger of ferroptosis, how mitochondrial damage plays a regulatory role in SI-AKI is still unclear. To explore the potential relationship between mitochondria and ferroptosis, we established a SI-AKI rat model by intraperitoneal injection of lipopolysaccharide (LPS). Transcriptome sequencing was used to detect changes in gene transcription levels in the control group, LPS 3 h group, LPS 6 h group and LPS 12 h group. The severity of kidney injury was determined based on serum creatinine (CRE), blood urea nitrogen (BUN), tissue HE staining, TUNEL staining and inflammatory factor levels. Cytoscape software was utilized to screen several mitochondria-related HUB genes, and NADH dehydrogenase [ubiquinone] ferrithionein 3 (NDUFS3) was selected for subsequent validation due to its novelty and feasibility. qRT-PCR, Western blot was employed to evaluate the expression of NDUFS3 in kidney tissues. GO enrichment analysis revealed that up-regulated genes in the LPS 12 h group were enriched in several cell death terms while down-regulated genes were enriched in lipid metabolic process and oxidation-reduction progress terms. Furthermore, Western blot, IHC, MDA, GSH and iron content levels were used to assess ferroptosis in the kidney tissue of the SI-AKI rats, dihydroethidium (DHE) assay and ATP kit were used to assess mitochondrial ROS levels and mitochondrial function. To further validate the function of NDUFS3, we constructed overexpression rats using hydrodynamic method by tail vein injection of pc DNA3.1-NDUFS3 overexpression plasmid. we utilized LPS to stimulate HK-2 cells and establish an in vitro model. We then overexpressed NDUFS3 using pcDNA 3.1. The overexpression of NDUFS3 was found to inhibit LPS-induced ferroptosis and mitochondrial damage in HK-2 cells, as evidenced by Western blot, MDA, GSH, divalent iron, ROS levels, Mitosox red, ATP content and transmission electron microscopy. Finally, the use of Compound C to inhibit AMPK in HK-2 cells demonstrated that NDUFS3 plays a protective role through the AMPK pathway. Therefore, our study supports the emerging role of NDUFS3 in SI-AKI, providing new potential mitochondria-related targets for the treatment of SI-AKI.

Targeted Delivery and ROS-Responsive Release of Lutein Nanoassemblies Inhibit Myocardial Ischemia-Reperfusion Injury by Improving Mitochondrial Function

Purpose

Myocardial ischemia-reperfusion injury (MI/RI) is associated with increased oxidative damage and mitochondrial dysfunction, resulting in an elevated risk of mortality. MI/RI may be alleviated by protecting cardiomyocytes from oxidative stress. Lutein, which belongs to a class of carotenoids, has proven to be effective in cardiovascular disease treatment due to its remarkable antioxidant properties, but its application is limited due to its poor stability and low bioavailability in vivo.

Methods

In this study, a delivery system was developed based on distearoyl phosphatidyl ethanolamine (DSPE)-thiol-ketone (TK)-PEG2K (polyethylene glycol 2000) (abbreviated as DTP) and PCM-SH (CWLSEAGPVVTVRALRGTGSW) to deliver lutein (abbreviated as lutein@DTPP) to damaged myocardium. First, lutein, lutein@DTP, or lutein@DTPP were injected through the tail vein once a day for 3 days and then MI/RI model rats were established by exposing rats to ischemia for 45 min and reperfusion for 6 h. We employed a range of experimental techniques including qRT-PCR, Western blotting, transmission electron microscopy, immunohistochemistry, immunofluorescence, flow cytometry, immunoprecipitation, molecular docking, and molecular dynamics simulations.

Results

Lutein@DTPP exhibited good myocardial targeting and ROS-responsive release. Our data suggested that lutein@DTPP effectively suppresses ferroptosis in cardiomyocytes. Mechanistically, we observed an upregulation of mouse double minute-2 (MDM2) in the hearts of MI/RI models and cardiomyocytes exposed to hypoxia/reoxygenation (H/R) conditions. In addition, NADH-ubiquinone oxidoreductase 75 kDa Fe-S protein 1 (NDUFS1) translocation from the cytosol to the mitochondria was inhibited by MDM2 upregulation. Notably, no significant variation in the total NDUFS1 expression was observed in H/R-exposed cardiomyocytes following treatment with siMDM2. Further study indicated that lutein facilitates the translocation of NDUFS1 from the cytosol to mitochondria by directly binding and sequestering MDM2, thereby improving mitochondrial function and inhibiting ferroptosis.

Conclusion

Lutein@DTPP promoted the mitochondrial translocation of NDUFS1 to restore mitochondrial function and inhibited the ferroptosis of cardiomyocytes by directly binding and sequestering MDM2.

Dexmedetomidine regulates exosomal miR-29b-3p from macrophages and alleviates septic myocardial injury by promoting autophagy in cardiomyocytes via targeting glycogen synthase kinase 3β

Background

Our previous research suggested that dexmedetomidine (Dex) promotes autophagy in cardiomyocytes, thus safeguarding them against apoptosis during sepsis. However, the underlying mechanisms of Dex-regulated autophagy have remained elusive. This study aimed to explore the role of exosomes and how they participate in Dex-induced cardioprotection in sepsis. The underlying microRNA (miRNA) mechanisms and possible therapeutic targets for septic myocardial injury were identified.

Methods

We first collected plasma exosomes from rats with sepsis induced by caecal ligation and puncture (CLP) with or without Dex treatment, and then incubated them with H9c2 cells to observe the effect on cardiomyocytes. Subsequently, the differential expression of miRNAs in plasma exosomes from each group of rats was identified through miRNA sequencing. miR-29b-3p expression in circulating exosomes of septic or non-septic patients, as well as in lipopolysaccharide-induced macrophages after Dex treatment, was analysed by quantitative real-time polymerase chain reaction (qRT-PCR). The autophagy level of cardiomyocytes after macrophage-derived exosome treatment was assessed by an exosome tracing assay, western blotting, and an autophagic flux assay. Specific miRNA mimics and inhibitors or small interfering RNAs were used to predict and evaluate the function of candidate miRNA and its target genes by qRT-PCR, annexin V/propyl iodide staining, autophagy flux analysis, and western blotting.

Results

We found that plasma-derived exosomes from Dex-treated rats promoted cardiomyocyte autophagy and exerted antiapoptotic effects. Additionally, they exhibited a high expression of miRNA, including miR-29b-3p. Conversely, a significant decrease in miR-29b-3p was observed in circulating exosomes from CLP rats, as well as in plasma exosomes from sepsis patients. Furthermore, Dex upregulated the lipopolysaccharide-induced decrease in miR-29b-3p expression in macrophage-derived exosomes. Exosomal miR-29b-3p from macrophages is thought to be transferred to cardiomyocytes, thus leading to the promotion of autophagy in cardiomyocytes. Database predictions, luciferase reporter assays, and small interfering RNA intervention confirmed that glycogen synthase kinase 3β (GSK-3β) is a target of miR-29b-3p. miR-29b-3p promotes cardiomyocyte autophagy by inhibiting GSK-3β expression and activation.

Conclusions

These findings demonstrate that Dex attenuates sepsis-associated myocardial injury by modulating exosome-mediated macrophage-cardiomyocyte crosstalk and that the miR-29b-3p/GSK-3β signaling pathway represents a hopeful target for the treatment of septic myocardial injury.

miR-199a-5p aggravates renal ischemia-reperfusion and transplant injury by targeting AKAP1 to disrupt mitochondrial dynamics

Renal ischemia-reperfusion injury (IRI) is a complex pathophysiological process and a major cause of delayed graft function (DGF) after transplantation. MicroRNA (miRNA) has important roles in the pathogenesis of IRI and may represent promising therapeutic targets for mitigating renal IRI. miRNA sequencing was performed to profile microRNA expression in mouse kidneys after cold storage and transplantation (CST). Lentivirus incorporating a miR-199a-5p modulator was injected into mouse kidney in situ before syngenetic transplantation and unilateral IRI to determine the effect of miR-199a-5p in vivo. miR-199a-5p mimic or inhibitor was transfected cultured tubular cells before ATP depletion recovery treatment to examine the role of miR-199a-5p in vitro. Sequencing data and microarray showed upregulation of miR-199a-5p in mice CST and human DGF samples. Lentivirus incorporating a miR-199a-5p mimic aggravated renal IRI, and protective effects were obtained with a miR-199a-5p inhibitor. Treatment with the miR-199a-5p inhibitor ameliorated graft function loss, tubular injury, and immune response after CST. In vitro experiments revealed exacerbation of mitochondria dysfunction upon ATP depletion and repletion model in the presence of the miR-199a-5p mimic, whereas dysfunction was attenuated when the miR-199a-5p inhibitor was applied. miR-199a-5p was shown to target A-kinase anchoring protein 1 (AKAP1) by double luciferase assay and miR-199a-5p activation reduced dynamin-related protein 1 (Drp1)-s637 phosphorylation and mitochondrial length. Overexpression of AKAP1 preserved Drp1-s637 phosphorylation and reduced mitochondrial fission. miR-199a-5p activation reduced AKAP1 expression, promoted Drp1-s637 dephosphorylation, aggravated the disruption of mitochondrial dynamics, and contributed to renal IRI.NEW & NOTEWORTHY This study identifies miR-199a-5p as a key regulator in renal ischemia-reperfusion injury through microRNA sequencing in mouse models and human delayed graft function. miR-199a-5p worsens renal IRI by aggravating graft dysfunction, tubular injury, and immune response, while its inhibition shows protective effects. miR-199a-5p downregulates A-kinase anchoring protein 1 (AKAP1), reducing dynamin-related protein 1 (Drp1)-s637 phosphorylation, increasing mitochondrial fission, and causing dysfunction. Targeting the miR-199a-5p/AKAP1/Drp1 axis offers therapeutic potential for renal IRI, as AKAP1 overexpression preserves mitochondrial integrity by maintaining Drp1-s637 phosphorylation.

Ibrutinib Promotes Atrial Fibrillation by Disrupting A-Kinase Anchoring Protein 1-Mediated Mitochondrial Quality Surveillance in Cardiomyocytes

Background: Ibrutinib, a potent Bruton's tyrosine kinase inhibitor with marked efficacy against hematological malignancies, is associated with the heightened risk of atrial fibrillation (AF). Although ibrutinib-induced AF is linked to enhanced oxidative stress, the underlying mechanisms remain unclear. Objective: This research aimed to explore the molecular mechanism and regulatory target in ibrutinib-induced AF. Methods: We performed in vivo electrophysiology studies using ibrutinib-treated mice, and then employed proteomic and single-cell transcriptomic analyses to identify the underlying targets and mechanisms. The effects of A-kinase anchoring protein 1 (AKAP1) depletion on mitochondrial quality surveillance (MQS) were evaluated using both in vivo and ex vivo AKAP1 overexpression models. Results: Atrial AKAP1 expression was significantly reduced in ibrutinib-treated mice, leading to inducible AF, atrial fibrosis, and mitochondrial fragmentation. These pathological changes were effectively mitigated in an overexpression model of ibrutinib-treated mice injected with an adeno-associated virus carrying Akap1. In ibrutinib-treated atrial myocytes, AKAP1 down-regulation promoted dynamin-related protein 1 (DRP1) translocation into mitochondria by facilitating DRP1 dephosphorylation at Ser637, thereby mediating excessive mitochondrial fission. Impaired MQS was also suggested by defective mitochondrial respiration, mitochondrial metabolic reprogramming, and suppressed mitochondrial biogenesis, accompanied by excessive oxidative stress and inflammatory activation. The ibrutinib-mediated MQS disturbance can be markedly improved with the inducible expression of the AKAP1 lentiviral system. Conclusions: Our findings emphasize the key role of AKAP1-mediated MQS disruption in ibrutinib-induced AF, which explains the previously observed reactive oxygen species overproduction. Hence, AKAP1 activation can be employed to prevent and treat ibrutinib-induced AF.

Sleep restriction exacerbates cardiac dysfunction in diabetic mice by causing cardiomyocyte death and fibrosis through mitochondrial damage

Diabetic cardiomyopathy (DCM) is a cardiovascular complication of diabetes mellitus with a poor prognosis and is the leading cause of death in diabetic patients. Sleep deficiency is not only recognized as an important risk factor for the development of type 2 DM, but is also associated with increased morbidity and mortality of cardiovascular disease. The underlying role and mechanisms of sleep restriction (SR) in DCM are far from clear. The KK/Upj-Ay mouse model of T2 DM was used as a study subject, and the small animal ultrasound imaging system was used to detect the function of the heart; immunopathological staining was used to clarify the histo-structural pathological alterations of the heart; and TUNEL staining, qPCR, transmission electron microscopy (TEM), and ELISA kits were used to detect apoptosis, oxidative stress, inflammation, and mitochondrial damage, and related molecular alterations. SR led to a significant increase in mortality, cardiac hypertrophy, necrosis, glycogen deposition and fibrosis further deteriorated in DM KK mice. SR increased cardiomyocyte death in KK mice through the Bax/Bcl2 pathway. In addition to this, SR not only exacerbated the inflammatory response, but also aggravated mitochondrial damage and promoted oxidative stress in KK mice through the PRDM16-PGC-1α pathway. Overall, SR exacerbates structural alterations and dysfunction through inflammation, oxidative stress, and apoptosis in DM KK mice, increasing the risk of death. Clinicians and diabetic patients are prompted to pay attention to sleep habits to avoid accelerating the transition of DCM to heart failure and inducing death due to poor sleep habits.

LIM kinase 2 activates cardiac fibroblasts and exacerbates postinfarction left ventricular remodeling via crosstalk between the canonical and non-canonical Wnt pathways

Ischemic heart failure rates rise despite decreased acute myocardial infarction (MI) mortality. Excessive myofibroblast activation post-MI leads to adverse remodeling. LIM kinases (LIMK1 and LIMK2) regulate cytoskeleton homeostasis and are pro-fibrotic markers in atrial fibrillation. However, their roles and mechanisms in postinfarction fibrosis and ventricular remodeling remain unclear. This study found that the expression of LIMKs elevated in the border zone (BZ) in mice MI models. LIMK1/2 double knockout (DKO) restrained pathological remodeling and reduced mortality by suppressing myofibroblast activation. By using adeno-associated virus (AAV) with a periostin promoter to overexpress LIMK1 or LIMK2, this study found that myofibroblast-specific LIMK2 overexpression diminished these effects in DKO mice, while LIMK1 did not. LIMK2 kinase activity was critical for myofibroblast proliferation by using AAV overexpressing mutant LIMK2 lack of kinase activity. According to phosphoproteome analysis, functional rescue experiments, co-immunoprecipitation, and protein-protein docking, LIMK2 led to the phosphorylation of β-catenin at Ser 552. LIMK2 nuclear translocation also played a role in myofibroblast proliferation after MI with the help of AAV overexpressing mutant LIMK2 without nuclear location signal. Chromatin immunoprecipitation sequencing identified that LIMK2 bound to Lrp6 promoter region in TGF-β treated cardiac fibroblasts, positively regulating Wnt signaling via Wnt receptor internalization. This study demonstrated that LIMK2 promoted myofibroblast proliferation and adverse cardiac remodeling after MI, by enhancing phospho-β-catenin (Ser552) and Lrp6 signaling. This suggested that LIMK2 could be a target for the treatment of postinfarction injury.

PGRMC1 promotes NSCLC stemness phenotypes by disrupting TRIM56-mediated ubiquitination of AHR

Cancer stem cells (CSCs) are responsible for tumor chemoresistance, and the aryl hydrocarbon receptor (AHR) is indispensable for maintaining CSC characteristics. Here, we aimed to investigate how the interaction between progesterone receptor membrane component 1 (PGRMC1) and AHR contributes to the maintenance of CSC phenotypes in non-small cell lung cancer (NSCLC). Clinical data and tissue microarray analyses indicated that patients with elevated PGRMC1 expression had poorer prognoses. Moreover, PGRMC1 overexpression enhanced CSC phenotypes and chemotherapy resistance in vitro and in vivo by modulating AHR ubiquitination. We then determined the specific interaction sites between PGRMC1 and AHR. Mass spectrometry screening identified tripartite motif containing 56 (TRIM56) as the E3 ligase targeting AHR. Notably, PGRMC1 overexpression inhibited the interaction between TRIM56 and AHR. Overall, our study revealed a regulatory mechanism that involves PGRMC1, AHR, and TRIM56, providing insights for developing CSC-targeting strategies in NSCLC treatment.

Role of gasotransmitters in necroptosis

Gasotransmitters are endogenous gaseous signaling molecules that can freely pass through cell membranes and transmit signals between cells, playing multiple roles in cell signal transduction. Due to extensive and ongoing research in this field, we have successfully identified many gasotransmitters so far, among which nitric oxide, carbon monoxide, and hydrogen sulfide are best studied. Gasotransmitters are implicated in various diseases related to necroptosis, such as cardiovascular diseases, inflammation, ischemia-reperfusion, infectious diseases, and neurological diseases. However, the mechanisms of their effects on necroptosis are not fully understood. This review focuses on endogenous gasotransmitter synthesis and metabolism and discusses their roles in necroptosis, aiming to offer new insights for the therapeutic approaches to necroptosis-associated diseases.

Transcriptome analysis of porcine oocytes during postovulatory aging

Decreased oocyte quality is a significant contributor to the decline in female fertility that accompanies aging in mammals. Oocytes rely on mRNA stores to support their survival and integrity during the protracted period of transcriptional dormancy as they await ovulation. However, the changes in mRNA levels and interactions that occur during porcine oocyte maturation and aging remain unclear. In this study, the mRNA expression profiles of porcine oocytes during the GV, MII, and aging (24 h after the MII stage) stages were explored by transcriptome sequencing to identify the key genes and pathways that affect oocyte maturation and postovulatory aging. The results showed that 10,929 genes were coexpressed in porcine oocytes during the GV stage, MII stage, and aging stage. In addition, 3037 genes were expressed only in the GV stage, 535 genes were expressed only in the MII stage, and 120 genes were expressed only in the aging stage. The correlation index between the GV and MII stages (0.535) was markedly lower than that between the MII and aging stages (0.942). A total of 3237 genes, which included 1408 upregulated and 1829 downregulated genes, were differentially expressed during porcine oocyte postovulatory aging (aging stage vs. MII stage). Key functional genes, including ATP2A1, ATP2A3, ATP2B2, NDUFS1, NDUFA2, NDUFAF3, SREBF1, CYP11A1, CYP3A29, GPx4, CCP110, STMN1, SPC25, Sirt2, SYCP3, Fascin1/2, PFN1, Cofilin, Tmod3, FLNA, LRKK2, CHEK1/2, DDB1/2, DDIT4L, and TONSL, and key molecular pathways, such as the calcium signaling pathway, MAPK signaling pathway, TGF-β signaling pathway, PI3K/Akt signaling pathway, FoxO signaling pathway, gap junctions, and thermogenesis, were found in abundance during porcine postovulatory aging. These genes are mainly involved in the regulation of many biological processes, such as oxidative stress, calcium homeostasis, mitochondrial function, and lipid peroxidation, during porcine oocyte postovulatory aging. These results contribute to a more in-depth understanding of the biological changes, key regulatory genes and related biological pathways that are involved in oocyte aging and provide a theoretical basis for improving the efficiency of porcine embryo production in vitro and in vivo.

Patchouli alcohol alleviates metabolic dysfunction-associated steatohepatitis via inhibiting mitochondria-associated endoplasmic reticulum membrane disruption-induced hepatic steatosis and inflammation in rats

Metabolic dysfunction-associated steatohepatitis (MASH) is a severe metabolic dysfunction-associated steatotic liver disease (MASLD) characterized by abnormal hepatic steatosis and inflammation. Previous studies have shown that Patchouli alcohol (PA), the primary component of Pogostemonis Herba, can alleviate digestive system diseases. However, its protection against MASH remains unclear. This study explored the protective effects and underlying mechanism of PA against high-fat diet-induced MASH in rats. Results showed that PA considerably reduced body weight, epididymal fat, and liver index and attenuated liver histological injury in MASH rats. PA alleviated hepatic injury by inhibiting steatosis and inflammation. These effects are associated with the improvement of SREBP-1c- and PPARα-mediated lipid metabolism and inhibition of the STING-signaling pathway-mediated inflammatory response. Moreover, PA-inhibited hepatic endoplasmic reticulum (ER) stress and mitochondrial dysfunction, reducing SREBP-1c and STING expressions and enhance PPARα expression. PA treatment had the strongest effect on the regulation of mitogen fusion protein 2 (Mfn2) in inhibiting mitochondrial dysfunction. Mfn2 is an important structural protein for binding ERs and mitochondria to form mitochondria-associated ER membranes (MAMs). MASH-mediated disruption of MAMs was inhibited after PA treatment-induced Mfn2 activation. Therefore, the pharmacological effect of PA on MASH is mainly attributed to the inhibition of MAM disruption-induced hepatic steatosis and inflammation. The findings of this study may have implications for MASH treatment that do not neglect the role of Mfn2-mediated MAMs.

Macrophage-derived extracellular vesicles represent a promising endogenous iron-chelating therapy for iron overload and cardiac injury in myocardial infarction

BACKGROUND

Cardiac iron overload and ferroptosis greatly contribute to the poor prognosis of myocardial infarction (MI). Iron chelator is one of the most promising strategies for scavenging excessive iron and alleviating cardiac dysfunction post MI. However, various side effects of existing chemical iron chelators restrict their clinical application, which calls for a more viable and safer approach to protect against iron injury in ischemic hearts.

RESULTS

In this study, we isolated macrophage-derived extracellular vesicles (EVs) and identified macrophage-derived EVs as a novel endogenous biological chelator for iron. The administration of macrophage-derived EVs effectively reduced iron overload in hypoxia-treated cardiomyocytes and hearts post MI. Moreover, the oxidative stress and ferroptosis induced by excessive iron were considerably suppressed by application of macrophage-derived EVs. Mechanistically, transferrin receptor (TfR), which was inherited from macrophage to the surface of EVs, endowed EVs with the ability to bind to transferrin and remove excess protein-bound iron. EVs with TfR deficiency exhibited a loss of function in preventing MI-induced iron overload and protecting the heart from MI injury. Furthermore, the iron-chelating EVs were ultimately captured and processed by macrophages in the liver.

CONCLUSIONS

These results highlight the potential of macrophage-derived EVs as a powerful endogenous candidate for iron chelation therapy, offering a novel and promising therapeutic approach to protect against iron overload-induced injury in MI and other cardiovascular diseases.

Inhibition of N-acetylglucosaminyltransferase V alleviates diabetic cardiomyopathy in mice by attenuating cardiac hypertrophy and fibrosis

BACKGROUND

The pathogenesis of diabetic cardiomyopathy is closely linked to abnormal glycosylation modifications. N-acetylglucosaminyltransferase V (GnT-V), which catalyzes the production of N-linked -1-6 branching of oligosaccharides, is involved in several pathophysiological mechanisms of many disorders, including cardiac hypertrophy and heart failure. However, the mechanism by which GnT-V regulates cardiac hypertrophy in diabetic cardiomyopathy is currently poorly understood. In this study, we investigated the role of GnT-V on myocardial hypertrophy in diabetic cardiomyopathy and elucidated the underlying mechanisms.

MATERIAL AND METHODS

Streptozotocin (STZ) was intraperitoneally injected into mice to induce diabetic cardiomyopathy. An adeno-associated virus (AAV) carrying negative control small hairpin RNA (shNC) or GnT-V-specifc small hairpin RNA (shGnT-V) was used to manipulate GnT-V expression. In our study, forty male C57BL/6J mice were randomly divided into four groups (10 mice per group): control mice with AAV-shNC, diabetic cardiomyopathy mice with AAV-shNC, control mice with AAV-shGnT-V, and diabetic cardiomyopathy mice with AAV-shGnT-V. In addition, H9C2 cells and primary neonatal cardiac fibroblasts treated with high glucose were used as a cell model of diabetes. Analysis of cardiac hypertrophy and fibrosis, as well as functional studies, were used to investigate the underlying molecular pathways.

RESULTS

AAV-mediated GnT-V silencing dramatically improved cardiac function and alleviated myocardial hypertrophy and fibrosis in diabetic mice. In vitro experiments demonstrated that GnT-V was elevated in cardiomyocytes and induced cardiomyocyte hypertrophy in response to high glucose stimulation. GnT-V knockdown significantly reduced the expression of the integrinβ1 signaling pathway, as evidenced by decreased downstream ERK1/2 activity, which inhibited cardiomyocyte hypertrophy accompanied by reduced ANP, BNP, and β-MHC expression. Furthermore, knocking down GnT-V expression lowered the TGF-β1-Smads signaling pathway, which reduced the expression of α-SMA, collagen I, and collagen III.

CONCLUSIONS

Overall, our research indicated that GnT-V may be a useful therapeutic target to treat diabetic cardiomyopathy, primarily in the inhibition of myocardial hypertrophy and fibrosis.

AKAP1 alleviates VSMC phenotypic modulation and neointima formation by inhibiting Drp1-dependent mitochondrial fission

The roles and mechanisms of A-kinase anchoring protein 1 (AKAP1) in vascular smooth muscle cell (VSMC) phenotypic modulation and neointima formation are currently unknown. AKAP1 is a mitochondrial PKA-anchored protein and maintains mitochondrial homeostasis. This study aimed to investigate how AKAP1/PKA signaling plays a protective role in inhibiting VSMC phenotypic transformation and neointima formation by regulating mitochondrial fission. The results showed that both PDGF-BB treatment and balloon injury reduced the transcription, expression, and mitochondrial anchoring of AKAP1. In vitro, the overexpression of AKAP1 significantly inhibited PDGF-BB mediated VSMC proliferation and migration, whereas AKAP1 knockdown further aggravated VSMC phenotypic transformation. Additionally, in the balloon injury model in vivo, AKAP1 overexpression reduced neointima formation, the muscle fiber area ratio, and rat VSMC proliferation and migration. Furthermore, PDGF-BB and balloon injury inhibited Drp1 phosphorylation at Ser637 and promoted Drp1 activity and mitochondrial midzone fission; AKAP1 overexpression reversed these effects. AKAP1 overexpression also inhibited the distribution of mitochondria at the plasma membrane and the reduction of PKARIIβ expression induced by PDGF-BB, as evidenced by an increase in mitochondria-plasma membrane distance as well as PKARIIβ protein levels. Moreover, the PKA agonist promoted Drp1 phosphorylation (Ser637) and inhibited PDGF-BB-mediated mitochondrial fission, cell proliferation, and migration. The PKA antagonist reversed the increase in Drp1 phosphorylation (Ser637) and the decline in mitochondrial midzone fission and VSMC phenotypic transformation caused by AKAP1 overexpression. The results of this study reveal that AKAP1 protects VSMCs against phenotypic modulation by improving Drp1 phosphorylation at Ser637 through PKA and inhibiting mitochondrial fission, thereby preventing neointima formation.

MARK4 aggravates cardiac dysfunction in mice with STZ-induced diabetic cardiomyopathy by regulating ACSL4-mediated myocardial lipid metabolism

Diabetic cardiomyopathy is a specific type of cardiomyopathy. In DCM, glucose uptake and utilization are impaired due to insulin deficiency or resistance, and the heart relies more heavily on fatty acid oxidation for energy, resulting in myocardial lipid toxicity-related injury. MARK4 is a member of the AMPK-related kinase family, and improves ischaemic heart failure through microtubule detyrosination. However, the role of MARK4 in cardiac regulation of metabolism is unclear. In this study, after successful establishment of a diabetic cardiomyopathy model induced by streptozotocin and a high-fat diet, MARK4 expression was found to be significantly increased in STZ-induced DCM mice. After AAV9-shMARK4 was administered through the tail vein, decreased expression of MARK4 alleviated diabetic myocardial damage, reduced oxidative stress and apoptosis, and facilitated cardiomyocyte mitochondrial fusion, and promoted myocardial lipid oxidation metabolism. In addition, through the RNA-seq analysis of differentially expressed genes, we found that MARK4 deficiency promoted lipid decomposition and oxidative metabolism by downregulating the expression of ACSL4, thus reducing myocardial lipid accumulation in the STZ-induced DCM model.

Novel insight into the role of A-kinase anchoring proteins (AKAPs) in ischemic stroke and therapeutic potentials

Ischemic stroke, a devastating disease associated with high mortality and disability worldwide, has emerged as an urgent public health issue. A-kinase anchoring proteins (AKAPs) are a group of signal-organizing molecules that compartmentalize and anchor a wide range of receptors and effector proteins and have a major role in stabilizing mitochondrial function and promoting neurodevelopmental development in the central nervous system (CNS). Growing evidence suggests that dysregulation of AKAPs expression and activity is closely associated with oxidative stress, ion disorder, mitochondrial dysfunction, and blood-brain barrier (BBB) impairment in ischemic stroke. However, the underlying mechanisms remain inadequately understood. This review provides a comprehensive overview of the composition and structure of A-kinase anchoring protein (AKAP) family members, emphasizing their physiological functions in the CNS. We explored in depth the molecular and cellular mechanisms of AKAP complexes in the pathological progression and risk factors of ischemic stroke, including hypertension, hyperglycemia, lipid metabolism disorders, and atrial fibrillation. Herein, we highlight the potential of AKAP complexes as a pharmacological target against ischemic stroke in the hope of inspiring translational research and innovative clinical approaches.

Quercetin Ameliorates Myocardial Injury in Diabetic Rats by Regulating Autophagy and Apoptosis through AMPK/mTOR Signaling Pathway

A high-glucose environment is involved in the progression of diabetes mellitus (DM). This study aims to explore the regulatory effects of quercetin (QUE) on autophagy and apoptosis after myocardial injury in rats with DM. The type 2 DM rat models were constructed using low-dose streptozotocin (STZ) treatment combined with a high-carbohydrate (HC) diet in vivo. Compared with the control group, the body weight was decreased, whereas blood pressure, blood glucose, and the LVW/BW ratio were increased in the diabetic group. The results showed that the myocardial fibers were disordered in the diabetic group. Moreover, we found that the myocardial collagen fibers, PAS-positive cells, and apoptosis were increased, whereas the mitochondrial structure was destroyed and autophagic vacuoles were significantly reduced in the diabetic group compared with the control group. The expression levels of autophagy-related proteins LC3 and Beclin1 were decreased, whereas the expression levels of P62, Caspae-3, and Bax/Bcl-2 were increased in the diabetic group in vitro and in vivo. Moreover, QUE treatment alleviated the cellular oxidative stress reaction under high-glucose environments. The results of immunoprecipitation (IP) showed that the autophagy protein Beclin1 was bound to Bcl-2, and the binding capacity increased in the HG group, whereas it decreased after QUE treatment, suggesting that QUE inhibited the binding capacity between Beclin1 and Bcl-2, thus leading to the preservation of Beclin1-induced autophagy. In addition, the blood pressure, blood glucose, and cardiac function of rats were improved following QUE treatment. In conclusion, QUE suppressed diabetic myocardial injury and ameliorated cardiac function by regulating myocardial autophagy and inhibition of apoptosis in diabetes through the AMPK/mTOR signaling pathway.

CAV3 alleviates diabetic cardiomyopathy via inhibiting NDUFA10-mediated mitochondrial dysfunction

BACKGROUND

The progression of diabetic cardiomyopathy (DCM) is noticeably influenced by mitochondrial dysfunction. Variants of caveolin 3 (CAV3) play important roles in cardiovascular diseases. However, the potential roles of CAV3 in mitochondrial function in DCM and the related mechanisms have not yet been elucidated.

METHODS

Cardiomyocytes were cultured under high-glucose and high-fat (HGHF) conditions in vitro, and db/db mice were employed as a diabetes model in vivo. To investigate the role of CAV3 in DCM and to elucidate the molecular mechanisms underlying its involvement in mitochondrial function, we conducted Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis and functional experiments.

RESULTS

Our findings demonstrated significant downregulation of CAV3 in the cardiac tissue of db/db mice, which was found to be associated with cardiomyocyte apoptosis in DCM. Importantly, cardiac-specific overexpression of CAV3 effectively inhibited the progression of DCM, as it protected against cardiac dysfunction and cardiac remodeling associated by alleviating cardiomyocyte mitochondrial dysfunction. Furthermore, mass spectrometry analysis and immunoprecipitation assays indicated that CAV3 interacted with NDUFA10, a subunit of mitochondrial complex I. CAV3 overexpression reduced the degradation of lysosomal pathway in NDUFA10, restored the activity of mitochondrial complex I and improved mitochondrial function. Finally, our study demonstrated that CAV3 overexpression restored mitochondrial function and subsequently alleviated DCM partially through NDUFA10.

CONCLUSIONS

The current study provides evidence that CAV3 expression is significantly downregulated in DCM. Upregulation of CAV3 interacts with NDUFA10, inhibits the degradation of lysosomal pathway in NDUFA10, a subunit of mitochondrial complex I, restores the activity of mitochondrial complex I, ameliorates mitochondrial dysfunction, and thereby protects against DCM. These findings indicate that targeting CAV3 may be a promising approach for the treatment of DCM.

Curcumin simultaneously improves mitochondrial dynamics and myocardial cell bioenergy after sepsis via the SIRT1-DRP1/PGC-1α pathway

Septic cardiomyopathy (SCM) is associated with an imbalance in mitochondrial quality and high mortality rates, with no effective treatment developed to date. Curcumin provides antioxidant, anti-inflammatory, cardiovascular, and mitochondrial protection. However, curcumin has not been confirmed to improve cardiac dysfunction in sepsis. We hypothesized that curcumin can reduce abnormal inflammatory responses by improving mitochondrial function as a novel mechanism to improve SCM. To explore this hypothesis, we used an in vivo male C57BL/6 mouse sepsis model and an in vitro model of lipopolysaccharide-stimulated HL-1 cells. The effects of curcumin on sepsis-induced cardiac dysfunction, inflammatory responses, and mitochondrial quality of cardiac cells were observed using quantitative polymerase chain reaction, western blotting, echocardiography, and transmission electron microscopy. Curcumin activated sirtuin 1 (SIRT1); increased expression of the mitochondrial biogenesis-related genes Pgc1α, Tfam, and Nrf2; reduced dynamin-related protein 1 translocation from the cytoplasm to mitochondria; and restored the mitochondrial morphology and function in cardiac cells. Accordingly, curcumin protected heart function after septic shock and alleviated the effects of SCM. SIRT1 knockdown reversed the protective effects of curcumin on mitochondria. Therefore, curcumin promotes mitochondrial biogenesis and inhibits mitochondrial fragmentation by activating SIRT1, thereby improving the mitochondrial quality and reducing oxidative stress in cardiomyocytes and sepsis-induced cardiac dysfunction. These findings provide new evidence supporting the use of curcumin to treat SCM.

Mitochondria-associated endoplasmic reticulum membrane (MAM): a dark horse for diabetic cardiomyopathy treatment

Diabetic cardiomyopathy (DCM), an important complication of diabetes mellitus (DM), is one of the most serious chronic heart diseases and has become a major cause of heart failure worldwide. At present, the pathogenesis of DCM is unclear, and there is still a lack of effective therapeutics. Previous studies have shown that the homeostasis of mitochondria and the endoplasmic reticulum (ER) play a core role in maintaining cardiovascular function, and structural and functional abnormalities in these organelles seriously impact the occurrence and development of various cardiovascular diseases, including DCM. The interplay between mitochondria and the ER is mediated by the mitochondria-associated ER membrane (MAM), which participates in regulating energy metabolism, calcium homeostasis, mitochondrial dynamics, autophagy, ER stress, inflammation, and other cellular processes. Recent studies have proven that MAM is closely related to the initiation and progression of DCM. In this study, we aim to summarize the recent research progress on MAM, elaborate on the key role of MAM in DCM, and discuss the potential of MAM as an important therapeutic target for DCM, thereby providing a theoretical reference for basic and clinical studies of DCM treatment.

Lipid overload-induced RTN3 activation leads to cardiac dysfunction by promoting lipid droplet biogenesis

Lipid droplet (LD) accumulation is a notable feature of obesity-induced cardiomyopathy, while underlying mechanism remains poorly understood. Here we show that mice fed with high-fat diet (HFD) exhibited significantly increase in cardiac LD and RTN3 expression, accompanied by cardiac function impairment. Multiple loss- and gain-of function experiments indicate that RTN3 is critical to HFD-induced cardiac LD accumulation. Mechanistically, RTN3 directly bonds with fatty acid binding protein 5 (FABP5) to facilitate the directed transport of fatty acids to endoplasmic reticulum, thereby promoting LD biogenesis in a diacylglycerol acyltransferase 2 dependent way. Moreover, lipid overload-induced RTN3 upregulation is due to increased expression of CCAAT/enhancer binding protein α (C/EBPα), which positively regulates RTN3 transcription by binding to its promoter region. Notably, above findings were verified in the myocardium of obese patients. Our findings suggest that manipulating LD biogenesis by modulating RTN3 may be a potential strategy for treating cardiac dysfunction in obese patients.

Fufang Zhenzhu Tiaozhi (FTZ) capsule ameliorates diabetes-accelerated atherosclerosis via suppressing YTHDF2-mediated m6A modification of SIRT3 mRNA

ETHNOPHARMACOLOGICAL RELEVANCE

Fufang Zhenzhu TiaoZhi (FTZ), a Chinese medicinal decoction, has continuously been used to treat metabolic syndrome. Atherosclerosis is the main pathological basis of cardiovascular disease. The N6 methyladenosine (m6A) modification is a highly dynamic and reversible process involving a variety of important biological processes.

AIM OF THE STUDY

Here, we investigated the therapeutic effects and mechanism of FTZ in diabetes-accelerated atherosclerosis.

MATERIALS AND METHODS

Doppler ultrasonography was used to examine the carotid intima-media thickness and plaque area in diabetic atherosclerosis patients. HFD mice were injected with streptozotocin to induce diabetes. HE and Oil red O staining were used to assess the effect of FTZ on lipid deposition. HUVECs were induced with HG/ox-LDL as a model of diabetic atherosclerosis. Furthermore, application of m6A methylation level kit, qRT-PCR, Western blot, tunel staining, reactive oxygen species staining and mPTP staining were performed to analyze the detailed mechanism.

RESULTS

Clinical trials of FTZ have shown obvious effect of lowering blood glucose and blood lipids. These effects were reversed after FTZ intervention. Compared with the control, lipid deposition decreased significantly after FTZ administration. FTZ reduced endothelial cell apoptosis. At the same time, we found that FTZ reversed the increase of methylation reader YTHDF2 caused by ox-LDL treatment. Subsequently, we discovered that YTHDF2 degraded SIRT3 mRNA, leading to endothelial cell apoptosis and oxidative stress.

CONCLUSION

FTZ attenuated diabetes-accelerated atherosclerosis by decreasing blood glucose and serum lipids levels, and increased endothelial cell antioxidant capacity, inhibited endothelial cell apoptosis via inhibiting YTHDF2-mediated m6A modification of SIRT3 mRNA, which reduced mRNA degradation.

Targeting the programmed cell death (PCD) signaling mechanism with natural substances for the treatment of diabetic cardiomyopathy (DCM)

Diabetic cardiomyopathy (DCM) is one of the severe complications of diabetes, characterized by structural and functional abnormalities in the hearts of diabetic patients without hypertension, coronary heart disease, or valvular heart disease. DCM can progress to heart failure, which is a significant cause of death in diabetic patients, but currently, there is no effective treatment available. Programmed cell death (PCD) is a genetically regulated form of cell death that includes apoptosis, autophagy, necroptosis, ferroptosis, and pyroptosis. PCD is essential for tissue homeostasis and normal development of the body. DCM is a complex condition, and abnormalities in the cascade of PCD signaling have been observed in its pathological process, suggesting that targeting PCD could be a potential therapeutic strategy. Studies have shown that natural substances can effectively modulate PCD to intervene in the treatment of DCM, and their use is safe. This review explores the role of different forms of PCD in the pathogenesis of DCM and summarizes the research progress in targeting PCD with natural substances to treat DCM. It can serve as a basis for further research and drug development to provide new treatment strategies for DCM patients.

Fiber-reinforced gelatin/β-cyclodextrin hydrogels loaded with platelet-rich plasma-derived exosomes for diabetic wound healing

Diabetic complications with high-glucose status (HGS) cause the dysregulated autophagy and excessive apoptosis of multiple-type cells, leading to the difficulty in wound self-healing. Herein, we firstly developed fiber-reinforced gelatin (GEL)/β-cyclodextrin (β-CD) therapeutic hydrogels by the modification of platelet-rich plasma exosomes (PRP-EXOs). The GEL fibers that were uniformly dispersed within the GEL/β-CD hydrogels remarkably enhanced the compression strengths and viscoelasticity. The PRP-EXOs were encapsulated in the hydrogels via the covalent crosslinking between the PRP-EXOs and genipin. The diabetic rat models demonstrated that the GEL/β-CD hydrogels and PRP-EXOs cooperatively promoted diabetic wound healing. On the one hand, the GEL/β-CD hydrogels provided the biocompatible microenvironments and active components for cell adhesion, proliferation and skin tissue regeneration. On the other hand, the PRP-EXOs in the therapeutic hydrogels significantly activated the autophagy and inhibited the apoptosis of human umbilical vein endothelial cells (HUVECs) and human skin fibroblasts (HSFs). The activation of autophagy and inhibition of apoptosis in HUVECs and HSFs induced the blood vessel creation, collagen formation and re-epithelialization. Taken together, this work proved that the incorporation of PRP-EXOs in a wound dressing was an effective strategy to regulate autophagy and apoptosis, and provide a novel therapeutic platform for diabetic wound healing.

Celastrol attenuates streptozotocin-induced diabetic cardiomyopathy in mice by inhibiting the ACE / Ang II / AGTR1 signaling pathway

BACKGROUND

Heart failure is closely correlated with diabetic cardiomyopathy (DCM) and can lead to mortality. Celastrol has long been utilized for the treatment of immune and inflammatory disorders. However, whether celastrol would exert protective effects on DCM has not been determined. This work aimed to explore the protective actions of celastrol on DCM and unravel the underlying mechanisms involved.

METHODS

A DCM model was constructed in mice by intraperitoneal administration of streptozotocin. ELISA and echocardiography were performed to examine myocardial injury markers and cardiac function, respectively. Morphological changes and fibrosis were assessed using H&E staining and Masson's staining. Inflammatory cytokines and fibrotic markers were detected by ELISA and RT-PCR. Endothelial nitric oxide synthase, apoptosis, and reactive oxygen species were detected by microscopic staining. Network pharmacology approaches, molecular docking analysis, ELISA, and Western blot were used for mechanism studies.

RESULTS

Celastrol alleviated diabetes-induced cardiac injury and remodeling. Celastrol also suppressed diabetes-induced production of inflammatory cytokines and reactive oxygen species, as well as cardiomyocyte apoptosis. The cardioprotective effects of celastrol were associated with its inhibition on the angiotensin-converting enzyme / angiotensin II / angiotensin II receptor type 1 signaling pathway.

CONCLUSION

Celastrol exhibits significant potential as an effective cardioprotective drug for DCM treatment. The underlying mechanisms can be attributed to the blockage of celastrol on the angiotensin-converting enzyme signaling pathway.

MFN2 deficiency promotes cardiac response to hypobaric hypoxia by reprogramming cardiomyocyte metabolism

AIM

Under hypobaric hypoxia (HH), the heart triggers various defense mechanisms including metabolic remodeling against lack of oxygen. Mitofusin 2 (MFN2), located at the mitochondrial outer membrane, is closely involved in the regulation of mitochondrial fusion and cell metabolism. To date, however, the role of MFN2 in cardiac response to HH has not been explored.

METHODS

Loss- and gain-of-function approaches were used to investigate the role of MFN2 in cardiac response to HH. In vitro, the function of MFN2 in the contraction of primary neonatal rat cardiomyocytes under hypoxia was examined. Non-targeted metabolomics and mitochondrial respiration analyses, as well as functional experiments were performed to explore underlying molecular mechanisms.

RESULTS

Our data demonstrated that, following 4 weeks of HH, cardiac-specific MFN2 knockout (MFN2 cKO) mice exhibited significantly better cardiac function than control mice. Moreover, restoring the expression of MFN2 clearly inhibited the cardiac response to HH in MFN2 cKO mice. Importantly, MFN2 knockout significantly improved cardiac metabolic reprogramming during HH, resulting in reduced capacity for fatty acid oxidation (FAO) and oxidative phosphorylation, and increased glycolysis and ATP production. In vitro data showed that down-regulation of MFN2 promoted cardiomyocyte contractility under hypoxia. Interestingly, increased FAO through palmitate treatment decreased contractility of cardiomyocyte with MFN2 knockdown under hypoxia. Furthermore, treatment with mdivi-1, an inhibitor of mitochondrial fission, disrupted HH-induced metabolic reprogramming and subsequently promoted cardiac dysfunction in MFN2-knockout hearts.

CONCLUSION

Our findings provide the first evidence that down-regulation of MFN2 preserves cardiac function in chronic HH by promoting cardiac metabolic reprogramming.

Endothelial MICU1 alleviates diabetic cardiomyopathy by attenuating nitrative stress-mediated cardiac microvascular injury

BACKGROUND

Myocardial microvascular injury is the key event in early diabetic heart disease. The injury of myocardial microvascular endothelial cells (CMECs) is the main cause and trigger of myocardial microvascular disease. Mitochondrial calcium homeostasis plays an important role in maintaining the normal function, survival and death of endothelial cells. Considering that mitochondrial calcium uptake 1 (MICU1) is a key molecule in mitochondrial calcium regulation, this study aimed to investigate the role of MICU1 in CMECs and explore its underlying mechanisms.

METHODS

To examine the role of endothelial MICU1 in diabetic cardiomyopathy (DCM), we used endothelial-specific MICU1ecKO mice to establish a diabetic mouse model and evaluate the cardiac function. In addition, MICU1 overexpression was conducted by injecting adeno-associated virus 9 carrying MICU1 (AAV9-MICU1). Transcriptome sequencing technology was used to explore underlying molecular mechanisms.

RESULTS

Here, we found that MICU1 expression is decreased in CMECs of diabetic mice. Moreover, we demonstrated that endothelial cell MICU1 knockout exacerbated the levels of cardiac hypertrophy and interstitial myocardial fibrosis and led to a further reduction in left ventricular function in diabetic mice. Notably, we found that AAV9-MICU1 specifically upregulated the expression of MICU1 in CMECs of diabetic mice, which inhibited nitrification stress, inflammatory reaction, and apoptosis of the CMECs, ameliorated myocardial hypertrophy and fibrosis, and promoted cardiac function. Further mechanistic analysis suggested that MICU1 deficiency result in excessive mitochondrial calcium uptake and homeostasis imbalance which caused nitrification stress-induced endothelial damage and inflammation that disrupted myocardial microvascular endothelial barrier function and ultimately promoted DCM progression.

CONCLUSIONS

Our findings demonstrate that MICU1 expression was downregulated in the CMECs of diabetic mice. Overexpression of endothelial MICU1 reduced nitrification stress induced apoptosis and inflammation by inhibiting mitochondrial calcium uptake, which improved myocardial microvascular function and inhibited DCM progression. Our findings suggest that endothelial MICU1 is a molecular intervention target for the potential treatment of DCM.

CD226 deficiency attenuates cardiac early pathological remodeling and dysfunction via decreasing inflammatory macrophage proportion and macrophage glycolysis in STZ-induced diabetic mice

Diabetic cardiomyopathy (DCM) is one of the main complications in type I diabetic patients. Activated macrophage is critical for directing the process of inflammation during the development of DCM. The present study focused on the roles of CD226 on macrophage function during the DCM progression. It has been found that the number of cardiac macrophages in the hearts of streptozocin (STZ)-induced diabetes mice was significantly increased compared with that in non-diabetes mice, and the expression level of CD226 on cardiac macrophages in STZ-induced diabetes mice was higher than that in non-diabetes mice. CD226 deficiency attenuated the diabetes-induced cardiac dysfunction and decreased the proportion of CD86+ F4/80+ macrophages in the diabetic hearts. Notably, adoptive transfer of Cd226-/- - bone marrow derived macrophages (BMDMs) alleviated diabetes-induced cardiac dysfunction, which may be due to the attenuated migration capacity of Cd226-/- -BMDM under high glucose stimulation. Furthermore, CD226 deficiency decreased the macrophage glycolysis accompanying by the downregulated hexokinase 2 (HK2) and lactate dehydrogenase A (LDH-A) expression. Taken together, these findings revealed the pathogenic roles of CD226 played in the process of DCM and provided a basis for the treatment of DCM.

Diabetic cardiomyopathy: Early diagnostic biomarkers, pathogenetic mechanisms, and therapeutic interventions

Diabetic cardiomyopathy (DCM) mainly refers to myocardial metabolic dysfunction caused by high glucose, and hyperglycemia is an independent risk factor for cardiac function in the absence of coronary atherosclerosis and hypertension. DCM, which is a severe complication of diabetes, has become the leading cause of heart failure in diabetic patients. The initial symptoms are inconspicuous, and patients gradually exhibit left ventricular dysfunction and eventually develop total heart failure, which brings a great challenge to the early diagnosis of DCM. To date, the underlying pathological mechanisms of DCM are complicated and have not been fully elucidated. Although there are therapeutic strategies available for DCM, the treatment is mainly focused on controlling blood glucose and blood lipids, and there is a lack of effective drugs targeting myocardial injury. Thus, a large percentage of patients with DCM inevitably develop heart failure. Given the neglected initial symptoms, the intricate cellular and molecular mechanisms, and the lack of available drugs, it is necessary to explore early diagnostic biomarkers, further understand the signaling pathways involved in the pathogenesis of DCM, summarize the current therapeutic strategies, and develop new targeted interventions.

PRDM16 exerts critical role in myocardial metabolism and energetics in type 2 diabetes induced cardiomyopathy

BACKGROUND

The prevalence of type 2 diabetes mellitus (T2DM) has increased over the past decades. Diabetic cardiomyopathy (DCM) is the leading cause of death in T2DM patients, however, the mechanism underlying DCM remains largely unknown. Here, we aimed to investigate the role of cardiac PR-domain containing 16 (PRDM16) in T2DM.

METHODS

We modeled mice with cardiac-specific deletion of Prdm16 by crossing the floxed Prdm16 mouse model with the cardiomyocyte-specific Cre transgenic mouse. The mice were continuously fed a chow diet or high-fat diet combining with streptozotocin (STZ) for 24 weeks to establish a T2DM model. DB/DB and adequate control mice were given a single intravenous injection of adeno-associated virus 9 (AAV9) carrying cardiac troponin T (cTnT) promoter-driven small hairpin RNA targeting PRDM16 (AAV9-cTnT-shPRDM16) from the retro-orbital venous plexus to knockout Prdm16 in the myocardium. There were at least 12 mice in each group. Mitochondrial morphology and function were detected using transmission electron microscopy, western blot determining the protein level of mitochondrial respiratory chain complex, mitotracker staining and Seahorse XF Cell Mito Stress Test Kit. Untargeted metabolomics analysis and RNA-seq analysis were performed to determine the molecular and metabolic changes associated with Prdm16 deficiency. BODIPY and TUNEL staining were used to detect lipid uptake and apoptosis. Co-immunoprecipitation and ChIP assays were conducted to examine the potential underlying mechanism.

RESULTS

Prdm16 cardiac-specific deficiency accelerated cardiomyopathy and worsened cardiac dysfunction in mice with T2DM, aggravating mitochondrial dysfunction and apoptosis both in vivo and in vitro, while PRDM16 overexpression the deterioration. Prdm16 deficiency also caused cardiac lipid accumulation resulting in metabolic and molecular alterations in T2DM mouse models. Co-IP and luciferase assays confirmed that PRDM16 targeted and regulated the transcriptional activity, expression and interaction of PPAR-α and PGC-1α, while the overexpression of PPAR-α and PGC-1α reversed Prdm16 deficiency-induced cellular dysfunction in T2DM model. Moreover, PRDM16 regulated PPAR-α and PGC-1α and affected mitochondrial function by mainly depending on epigenetic regulation of H3K4me3.

CONCLUSIONS

These findings suggest that PRDM16 exerted its protective role in myocardial lipid metabolism and mitochondrial function in T2DM in a histone lysine methyltransferase activity-dependent manner by regulating PPAR-α and PGC-1α.

Zuogui-Jiangtang-Yishen decoction prevents diabetic kidney disease: Intervene pyroptosis induced by trimethylamine n-oxide through the mROS-NLRP3 axis

BACKGROUND

Nowadays, diabetic kidney disease (DKD) has become one of the most threatening to the end-stage renal diseases, and the early prevention of DKD is inevitable for Diabetes Mellitus (DM) patients.

AIMS

Pyroptosis, a programmed cell death that mediates renal inflammation induced early renal injury. The trimethylamine n-oxide (TMAO) was also an independent risk factor for renal injury. Here, the associations between TMAO-induced pyroptosis and pathogenesis of DKD were studied, and the potential mechanism of Zuogui-Jiangtang-Yishen (ZGJTYS) decoction to prevent DKD was further investigated.

METHOD

Using Goto-Kakizaki (GK) rats to establish the early DKD models. The 16S-ribosomal RNA (16S rRNA) sequencing, fecal fermentation and UPLC-MS targeted metabolism techniques were combined to explore the changes of gut-derived TMAO level under the background of DKD and the effects of ZGJTYS. The proximal convoluted tubule epithelium of human renal cortex (HK-2) cells was adopted to explore the influence of pyroptosis regulated by TMAO.

RESULTS

It was demonstrated that ZGJTYS could prevent the progression of DKD by regulating glucolipid metabolism disorder, improving renal function and delaying renal pathological changes. In addition, we illustrated that gut-derived TMAO could promote DKD by activating the mROS-NLRP3 axis to induce pyroptosis. Furthermore, besides interfering with the generation of TMAO through gut microbiota, ZGJTYS inhibited TMAO-induced pyroptosis with a high-glucose environment and the underlying mechanism was related to the regulation of mROS-NLRP3 axis.

CONCLUSION

Our results suggested that ZGJTYS inhibited the activation of pyroptosis by gut-derived TMAO via the mROS-NLRP3 axis to prevent DKD.

Mitochondrial Dysfunction in Cardiac Diseases and Therapeutic Strategies

Mitochondria are the main site of intracellular synthesis of ATP, which provides energy for various physiological activities of the cell. Cardiomyocytes have a high density of mitochondria and mitochondrial damage is present in a variety of cardiovascular diseases. In this paper, we describe mitochondrial damage in mitochondrial cardiomyopathy, congenital heart disease, coronary heart disease, myocardial ischemia-reperfusion injury, heart failure, and drug-induced cardiotoxicity, in the context of the key roles of mitochondria in cardiac development and homeostasis. Finally, we discuss the main current therapeutic strategies aimed at alleviating mitochondrial impairment-related cardiac dysfunction, including pharmacological strategies, gene therapy, mitochondrial replacement therapy, and mitochondrial transplantation. It is hoped that this will provide new ideas for the treatment of cardiovascular diseases.

Grpel2 maintains cardiomyocyte survival in diabetic cardiomyopathy through DLST-mediated mitochondrial dysfunction: a proof-of-concept study

BACKGROUND

Diabetic cardiomyopathy (DCM) has been considered as a major threat to health in individuals with diabetes. GrpE-like 2 (Grpel2), a nucleotide exchange factor, has been shown to regulate mitochondrial import process to maintain mitochondrial homeostasis. However, the effect and mechanism of Grpel2 in DCM remain unknown.

METHODS

The streptozotocin (STZ)-induced DCM mice model and high glucose (HG)-treated cardiomyocytes were established. Overexpression of cardiac-specific Grpel2 was performed by intramyocardial injection of adeno-associated virus serotype 9 (AAV9). Bioinformatics analysis, co-immunoprecipitation (co-IP), transcriptomics profiling and functional experiments were used to explore molecular mechanism of Grpel2 in DCM.

RESULTS

Here, we found that Grpel2 was decreased in DCM induced by STZ. Overexpression of cardiac-specific Grpel2 alleviated cardiac dysfunction and structural remodeling in DCM. In both diabetic hearts and HG-treated cardiomyocytes, Grpel2 overexpression attenuated apoptosis and mitochondrial dysfunction, including decreased mitochondrial ROS production, increased mitochondrial respiratory capacities and increased mitochondrial membrane potential. Mechanistically, Grpel2 interacted with dihydrolipoyl succinyltransferase (DLST), which positively mediated the import process of DLST into mitochondria under HG conditions. Furthermore, the protective effects of Grpel2 overexpression on mitochondrial function and cell survival were blocked by siRNA knockdown of DLST. Moreover, Nr2f6 bond to the Grpel2 promoter region and positively regulated its transcription.

CONCLUSION

Our study provides for the first time evidence that Grpel2 overexpression exerts a protective effect against mitochondrial dysfunction and apoptosis in DCM by maintaining the import of DLST into mitochondria. These findings suggest that targeting Grpel2 might be a promising therapeutic strategy for the treatment of patients with DCM.

Phosphoproteomics Profiling Defines a Target Landscape of the Basophilic Protein Kinases AKT, S6K, and RSK in Skeletal Myotubes

Phosphorylation-dependent signal transduction plays an important role in regulating the functions and fate of skeletal muscle cells. Central players in the phospho-signaling network are the protein kinases AKT, S6K, and RSK as part of the PI3K-AKT-mTOR-S6K and RAF-MEK-ERK-RSK pathways. However, despite their functional importance, knowledge about their specific targets is incomplete because these kinases share the same basophilic substrate motif RxRxxp[ST]. To address this, we performed a multifaceted quantitative phosphoproteomics study of skeletal myotubes following kinase inhibition. Our data corroborate a cross talk between AKT and RAF, a negative feedback loop of RSK on ERK, and a putative connection between RSK and PI3K signaling. Altogether, we report a kinase target landscape containing 49 so far unknown target sites. AKT, S6K, and RSK phosphorylate numerous proteins involved in muscle development, integrity, and functions, and signaling converges on factors that are central for the skeletal muscle cytoskeleton. Whereas AKT controls insulin signaling and impinges on GTPase signaling, nuclear signaling is characteristic for RSK. Our data further support a role of RSK in glucose metabolism. Shared targets have functions in RNA maturation, stability, and translation, which suggests that these basophilic kinases establish an intricate signaling network to orchestrate and regulate processes involved in translation.

Proteomic profiling reveals dysregulated mitochondrial complex subunits responsible for myocardial toxicity induced by SiNPs

The relationship between environmental exposure to silica nanoparticles (SiNPs) and adverse cardiac outcomes has received more attention. Our recent work has revealed a size-dependent impact of the intratracheal instilled SiNPs on cardiac health of ApoE^-/- mice using nanoscale SiNPs-60 and submicro-sized SiNPs-300, but the underlying mechanism of action still remains unclear. Hence, we identified proteins and protein networks perturbed by SiNPs in myocardial tissues of ApoE^-/- mice by using LC-MS/MS-based quantitative proteomics. A set of 435 differentially expressed proteins (DEPs) were screened in response to SiNPs, which mainly enriched in the mitochondria and functioned in cell metabolism, biosynthesis and signal transduction. KEGG analysis showed that DEPs were significantly associated with oxidative phosphorylation and cardiomyopathy. The protein-protein interaction (PPI) network revealed 9 DEPs (e.g., Ndufs1, Ndufv1, Cox4i1) as potential biomarkers of SiNPs-induced myocardial toxicity. Of note, all the 9 candidate proteins were subunits of mitochondria respiratory chain complex, and their expressions were dependent on particle size, which were remarkably down-regulated by SiNPs-60 but not by SiNPs-300. More importantly, the correlation analysis verified the 9 dysregulated mitochondria complex protein subunits strongly correlated to the biochemical and functional indexes of cardiac injury in response to SiNPs. In conclusion, our study firstly provided significant proteomic insights into the potential molecular mechanisms underlying SiNPs-elicited cardiotoxicity, with the dysregulated mitochondrial complex subunits as core regulatory molecules. Overall, our study would provide the scientific basis for the molecular actions and mechanisms of toxicity induced by SiNPs.

Ferroptosis: roles and molecular mechanisms in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a serious complication of type 1 and type 2 diabetes, which leads to the aggravation of myocardial fibrosis, disorders involving systolic and diastolic functions, and increased mortality of patients with diabetes through mechanisms such as glycolipid toxicity, inflammatory response, and oxidative stress. Ferroptosis is a form of iron-dependent regulatory cell death that is attributed to the accumulation of lipid peroxides and an imbalance in redox regulation. Increased production of lipid reactive oxygen species (ROS) during ferroptosis promotes oxidative stress and damages myocardial cells, leading to myocardial systolic and diastolic dysfunction. Overproduction of ROS is an important bridge between ferroptosis and DCM, and ferroptosis inhibitors may provide new targets for the treatment of patients with DCM.

Emerging Roles of NDUFS8 Located in Mitochondrial Complex I in Different Diseases

NADH:ubiquinone oxidoreductase core subunit S8 (NDUFS8) is an essential core subunit and component of the iron-sulfur (FeS) fragment of mitochondrial complex I directly involved in the electron transfer process and energy metabolism. Pathogenic variants of the NDUFS8 are relevant to infantile-onset and severe diseases, including Leigh syndrome, cancer, and diabetes mellitus. With over 1000 nuclear genes potentially causing a mitochondrial disorder, the current diagnostic approach requires targeted molecular analysis, guided by a combination of clinical and biochemical features. Currently, there are only several studies on pathogenic variants of the NDUFS8 in Leigh syndrome, and a lack of literature on its precise mechanism in cancer and diabetes mellitus exists. Therefore, NDUFS8-related diseases should be extensively explored and precisely diagnosed at the molecular level with the application of next-generation sequencing technologies. A more distinct comprehension will be needed to shed light on NDUFS8 and its related diseases for further research. In this review, a comprehensive summary of the current knowledge about NDUFS8 structural function, its pathogenic mutations in Leigh syndrome, as well as its underlying roles in cancer and diabetes mellitus is provided, offering potential pathogenesis, progress, and therapeutic target of different diseases. We also put forward some problems and solutions for the following investigations.