Retinol dehydrogenase 10 reduction mediated retinol metabolism disorder promotes diabetic cardiomyopathy in male mice

Cardiac endothelial cells and cardiomyocytes alter their communication properties in diabetic mice

OBJECTIVE

We aimed to explore the heterogeneities and communication properties of cardiac CMs and ECs in diabetes.

METHODS

GSE213337 dataset was retrieved from NCBI Gene Expression Omnibus, containing the single-cell RNA sequencing data of hearts from the control and streptozotocin-induced diabetic mice. Cell cluster analysis was performed to identify the cell atlas. Data of CMs and ECs were extracted individually for re-cluster analysis, functional enrichment analysis and trajectory analysis. Cell communication analysis was conducted to explore the altered signals and significant ligand-receptor interactions.

RESULTS

Eleven cell types were identified in the heart tissue. CMs were re-clustered into four subclusters, and cluster 4 was dominant in diabetic condition and enriched in cellular energy metabolism processes. ECs were re-clustered into six subclusters, and clusters 2, 4 and 5 were dominant in the diabetic condition and mainly enriched in cellular energy metabolism and lipid transport processes. The cellular communication network was altered in the diabetic heart. ECs dominated the overall signaling and notably increased the ANGPTL and SEMA4 signals in the diabetic heart. Four significant ligand-receptor pairs implicating the two signals contributed to the communication between ECs and other cell types, including Angptl1-(Itga1 + Itgb1), Angptl4-Cdh5, Angptl4-Sdc3, and Sema4a-(Nrp + Plxna2). The ligand Angptl4 engaged in ECs-CMs communication in a paracrine manner.

CONCLUSION

Single-cell sequencing analysis revealed heterogeneities of ECs and CMs in diabetes, Angptl4-Cdh5 and Angptl4-Sdc3 were involved in the communication between ECs and CMs in diabetes.

Metabolic Coordination Structures Contribute to Diabetic Myocardial Dysfunction

BACKGROUND

Individuals with diabetes are susceptible to cardiac dysfunction and heart failure, potentially resulting in mortality. Metabolic disorders frequently occur in patients with diabetes, and diabetes usually leads to remodeling of heart structure and cardiac dysfunction. However, the contribution and underlying mechanisms of metabolic and structural coupling in diabetic cardiac dysfunction remain elusive.

METHODS

Two mouse models of type 2 diabetes (T2DM) were used to assess alterations in glucose/lipid metabolism and cardiac structure. The potential metabolic-structural coupling molecule ACBP (acyl-coenzyme A-binding protein) was screened from 4 published datasets of T2DM-associated heart disease. In vivo loss-of-function and gain-of-function approaches were used to investigate the role of ACBP in diabetic cardiac dysfunction. The underlying mechanisms of metabolic and structural coupling were investigated by stable-isotope tracing metabolomics, coimmunoprecipitation coupled with mass spectrometry, and chromatin immunoprecipitation sequencing.

RESULTS

Diabetic mouse hearts exhibit enhanced lipid metabolism and impaired ultrastructure with marked cardiac systolic and diastolic dysfunction. Analysis of 4 T2DM public datasets revealed that Acbp was a significant lipid metabolism gene whose expression was upregulated. Consistently, ACBP expression levels were markedly elevated in the hearts of patients with diabetes and diabetic mice. Moreover, we constructed cardiomyocyte-specific Acbp knockout mice that exhibited attenuation of T2DM-induced cardiac remodeling and cardiac dysfunction, including attenuation of cardiac hypertrophy, fibrosis, ultrastructural damage, and enhanced cardiomyocyte contractility and cardiac function. Conversely, cardiac-specific Acbp overexpression via adeno-associated virus type 9, which encodes Acbp under the cTnT (cardiac troponin T) promoter, recapitulated cardiac dysfunction. Mechanistically, cardiac-specific Acbp knockout enhances glucose utilization in diabetic cardiomyocytes, suggesting a potential compensatory mechanism for insufficient ATP levels, highlighting its metabolic role. In addition, combined with mass spectrometry analysis revealed that ACBP binds MyBPC3 (myosin-binding protein C3) in T2DM individuals, which potentially prevents MyBPC3 from assisting the formation of cross-bridge structures between myosin and actin, thereby impairing myocardial contraction. Importantly, chromatin immunoprecipitation sequencing revealed that peroxisome proliferator-activated receptor γ regulates the transcriptional activity of Acbp.

CONCLUSIONS

Our findings demonstrated that ACBP mediates the bidirectional regulation of cardiomyocyte metabolic and structural associations and identified a promising therapeutic target for ameliorating cardiac dysfunction in patients with T2DM.

Cold-Induced DHRS4 Promotes Thermogenesis via Enhanced Fatty Acid β-Oxidation in Porcine Subcutaneous Adipocytes

Adipose tissue exhibits remarkable plasticity in adapting to thermal stress, yet the epigenetic mechanisms coordinating metabolic reprogramming in large mammals-particularly in livestock species lacking classical brown adipose tissue (BAT) such as swine-remain elusive. Using a porcine cold exposure model, we investigated adipose adaptation mechanisms through integrated single-cell RNA sequencing and bulk transcriptomic analyses of subcutaneous adipose tissue (subWAT). We identified a cold-induced thermogenic adipocyte subpopulation, characterized by upregulated DHRS4 expression. Mechanistically, cold exposure induced hypomethylation at the DHRS4 promoter locus, enhancing its expression to potentiate fatty acid β-oxidation, accompanied by thermogenic capacity upregulation. Our findings establish DHRS4 as an epigenetic-metabolic switch governing cold adaptation and a potential target for improving cold resistance in swine production systems.

Integrated cascade antioxidant nanozymes-Cu5.4O@CNDs combat acute liver injury by regulating retinol metabolism

Background: Acute liver failure (ALF) represents a critical medical condition marked by the abrupt onset of hepatocyte damage, commonly induced by etiological factors such as hepatic ischemia/reperfusion injury (HIRI) and drug-induced hepatotoxicity. Across various types of liver injury, oxidative stress, heightened inflammatory responses, and dysregulated hepatic retinol metabolism are pivotal contributors, particularly in the context of excessive reactive oxygen species (ROS). Methods: C-dots were combined with Cu5.4O USNPs to synthesize a cost-effective nanozyme, Cu5.4O@CNDs, which mimics the activity of cascade enzymes. The in vitro evaluation demonstrated the ROS scavenging and anti-inflammatory capacity of Cu5.4O@CNDs. The therapeutic potential of Cu5.4O@CNDs was evaluated in vivo using mouse models of hepatic ischemia/reperfusion injury and LPS/D-GalN induced hepatitis, with transcriptome analysis conducted to clarify the mechanism underlying hepatoprotection. Results: The Cu5.4O@CNDs demonstrated superoxide dismutase (SOD) and catalase (CAT) enzyme activities, as well as hydroxyl radical (·OH) scavenging capabilities, effectively mitigating ROS in vitro. Furthermore, the Cu5.4O@CNDs exhibited remarkable targeting efficacy towards inflammation cells induced by H2O2 and hepatic tissues in murine models of hepatitis, alongside exhibiting favorable biocompatibility in both in vitro and in vivo settings. Moreover, it has been demonstrated that Cu5.4O@CNDs effectively scavenged ROS, thereby enhancing cell survival in vitro. Additionally, Cu5.4O@CNDs exhibited significant therapeutic efficacy in mice models of HIRI and lipopolysaccharide-induced acute lung injury (LPS-ALI). This efficacy was achieved through the modulation of the ROS response and hepatic inflammatory network, as well as the amelioration of disruptions in hepatic retinol metabolism. Conclusions: In summary, this study demonstrates that Cu5.4O@CNDs exhibit significant potential for the treatment of various acute liver injury conditions, suggesting their promise as an intervention strategy for clinical application.

Metabolic Profiling Reveals Diagnostic Biomarkers for Distinguishing Myocarditis From Acute Myocardial Infarction

Background: Distinguishing between myocarditis (MC) and acute myocardial infarction (AMI) in the early stages is crucial due to their similar symptoms yet vastly different treatment protocols. This study seeks to utilize metabolomics techniques to differentiate between MC and AMI. Methods: Plasma samples from 15 patients with MC and 12 patients with AMI were collected. Metabolic profiles of plasma from the two groups of patients were obtained using ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS), identifying metabolites with significant differences. Results: We identified 30 significantly different metabolites in both diseases. In patients with MC, 17 metabolites were upregulated, including 5-hydroxy-L-tryptophan and LysoPC (18:2(9Z,12Z)), while 13 metabolites were downregulated, such as 11-cis-retinol, L-glutamate, and hydroxynicotinic acid. KEGG enrichment analysis revealed that the altered metabolites were enriched in tryptophan metabolism, linoleic acid metabolism, primary bile acid biosynthesis, nitrogen metabolism, and retinol metabolism. Biomarker analysis via receiver-operating characteristic curves highlighted 11-cis-retinol as the predominant biomarker, with an AUC value of 0.917. Conclusions: In conclusion, patients experiencing AMI and MC undergo significant metabolic reprogramming. Metabolites exhibiting abnormal expression in peripheral blood hold diagnostic value for distinguishing between AMI and MC in clinical settings. 11-cis-retinol proved to be the pivotal biomarker for AMI, potentially aiding in the development of a robust predictive model for distinguishing between MC and AMI in clinical settings.

Berberine partially ameliorates cardiolipotoxicity in diabetic cardiomyopathy by modulating SIRT3-mediated lipophagy to remodel lipid droplets homeostasis

BACKGROUND AND PURPOSE

Emerging evidence indicated that the excessive lipid droplets (LDs) accumulation and lipotoxicity play a significant role in the development of diabetic cardiomyopathy (DCM), yet the regulatory mechanisms governing the function of cardiac LDs are still unknown. Lipophagy has been shown to be involved in the maintenance of LDs homeostasis. The objective of this study was to explore the mechanism of lipophagy in cardiomyocytes and investigate whether berberine could mitigate DCM by modulating this pathway.

EXPERIMENTAL APPROACH

Bioinformatics analysis identified disorders of lipid metabolism and autophagy in DCM. To carry out further research, db/db mice were utilized. Furthermore, H9C2 cells treated with palmitic acid were employed as a model to explore the molecular mechanisms involved in myocardial lipotoxicity.

KEY RESULTS

The results showed that lipophagy was impaired in DCM. Mechanistically, sirtuin 3 (SIRT3) was demonstrated to regulate lipophagy in cardiomyocytes. SIRT3 was down-regulated in DCM. Conversely, activation of SIRT3 by the activator nicotinamide riboside (NR) could promote lipophagy to alleviate PA-induced lipotoxicity in H9C2 cells. Moreover, berberine administration markedly mitigated diabetes-induced cardiac dysfunction and hypertrophy in db/db mice, which dependent on SIRT3-mediated lipophagy.

CONCLUSION AND IMPLICATIONS

Collectively, SIRT3 could moderate cardiac lipotoxicity in DCM by promoting lipophagy, suggesting that the regulation of SIRT3-mediated lipophagy may be a promising strategy for treating DCM. The findings indicate that the therapeutic potential of berberine for DCM is associated with lipophagy.

Relationship between retinol metabolism and hepatocellular carcinoma: a comprehensive analysis of Mendelian randomization, prognostic characteristic and experiment

PURPOSE

Retinol metabolism is intricately linked to the occurrence and progression of hepatocellular carcinoma (HCC); however, the precise pathogenic relationship between them remains elusive. The aim of this study was to elucidate the characteristics of retinol metabolism in HCC through Mendelian randomization, prognostic model and experimental validation.

METHODS

We used transcriptomic data related to HCC in TCGA and GEO databases for a variety of machine learning, including differential gene expression analysis, functional enrichment analysis, protein-protein network interaction, ceRNA regulatory network, and single-cell sequencing analysis. Mendelian randomization analysis was used to elucidate the causal analysis of retinol metabolism and the occurrence of HCC. Consensus cluster analysis was performed based on 11 retinol metabolism-related genes, and the prognostic model was constructed by Lasso regression and Cox regression analysis. The expression level of RDH16 gene was detected in cell lines and clinical samples, and finally the function of RDH16 gene and its regulatory relationship with miR- 665 were verified by in vitro cell experiments.

RESULTS

Differentially expressed genes were mainly concentrated in the retinol metabolic pathway. Mendelian randomization analysis showed that decreased retinol metabolic activity was causally associated with the occurrence of HCC. RDH16 gene was significantly lower expressed in HCC, and inhibition of RDH16 gene expression could promote the proliferation, migration and invasion of HCC cells and inhibit cell apoptosis. miR- 665 is an upstream regulator of RDH16 gene, which can inhibit the expression and function of RDH16.

CONCLUSION

The decrease of retinol metabolic activity can promote the occurrence and development of HCC. Targeting retinol metabolic pathway may be a new direction for the treatment of HCC.

Paeoniflorin: a review of its pharmacology, pharmacokinetics and toxicity in diabetes

The escalating global prevalence of diabetes underscores the urgency of addressing its treatment and associated complications. Paeoniflorin, a monoterpenoid glycoside compound, has garnered substantial attention in recent years owing to its potential therapeutic efficacy in diabetes management. Thus, this study aims to systematically overview the pharmacological effects, pharmacokinetics and toxicity of paeoniflorin in diabetes. Plenty of evidences have verified that paeoniflorin improves diabetes and its complication through reducing blood sugar, enhancing insulin sensitivity, regulating gut microbiota and autophagy, restoration of mitochondrial function, regulation of lipid metabolism, anti-inflammation, anti-oxidative stress, inhibition of apoptosis, immune regulation and so on. Paeoniflorin possess the characteristics of rapid absorption, wide distribution, rapid metabolism and renal excretion. Meanwhile, toxicity studies have suggested that paeoniflorin has low acute toxicity, minimal subacute and chronic toxicity, and no genotoxic or mutational toxic effects. In conclusion, this paper systematically elucidates the potential therapeutic application and safety profile of paeoniflorin in diabetes management.

Retinoic acid signaling and metabolism in heart failure

Nearly 70 years after studies first showed that the offspring of vitamin A (retinol, ROL)-deficient rats exhibit structural cardiac defects and over 20 years since the role of vitamin A's potent bioactive metabolite hormone, all-trans retinoic acid (ATRA), was elucidated in embryonic cardiac development, the role of the vitamin A metabolites, or retinoids, in adult heart physiology and heart and vascular disease, remains poorly understood. Studies have shown that low serum levels of retinoic acid correlate with higher all-cause and cardiovascular mortality, though the relationship between circulating retinol and ATRA levels, cardiac tissue ATRA levels, and intracellular cardiac ATRA signaling in the context of heart and vascular disease has only begun to be addressed. We have recently shown that patients with idiopathic dilated cardiomyopathy show a nearly 40% decline of in situ cardiac ATRA levels, despite adequate local stores of retinol. Moreover, we and others have shown that the administration of ATRA forestalls the development of heart failure (HF) in rodent models. In this review, we summarize key facets of retinoid metabolism and signaling and discuss mechanisms by which impaired ATRA signaling contributes to several HF hallmarks including hypertrophy, contractile dysfunction, poor calcium handling, redox imbalance, and fibrosis. We highlight unresolved issues in cardiac ATRA metabolism whose pursuit will help refine therapeutic strategies aimed at restoring ATRA homeostasis.

Exercise in Diabetic Cardiomyopathy: Its Protective Effects and Molecular Mechanism

Diabetic cardiomyopathy (DCM) is one of the cardiovascular complications of diabetes, characterized by the development of ventricular systolic and diastolic dysfunction due to factors such as inflammation, oxidative stress, fibrosis, and disordered glucose metabolism. As a sustainable therapeutic approach, exercise has been reported in numerous studies to regulate blood glucose and improve abnormal energy metabolism through various mechanisms, thereby ameliorating left ventricular diastolic dysfunction and mitigating DCM. This review summarizes the positive impacts of exercise on DCM and explores its underlying molecular mechanisms, providing new insights and paving the way for the development of tailored exercise programs for the prophylaxis and therapy of DCM.

Ferroptosis: mechanism and role in diabetes-related cardiovascular diseases

Cardiovascular diseases represent the principal cause of death and comorbidity among people with diabetes. Ferroptosis, an iron-dependent non-apoptotic regulated cellular death characterized by lipid peroxidation, is involved in the pathogenesis of diabetic cardiovascular diseases. The susceptibility to ferroptosis in diabetic hearts is possibly related to myocardial iron accumulation, abnormal lipid metabolism and excess oxidative stress under hyperglycemia conditions. Accumulating evidence suggests ferroptosis can be the therapeutic target for diabetic cardiovascular diseases. This review summarizes ferroptosis-related mechanisms in the pathogenesis of diabetic cardiovascular diseases and novel therapeutic choices targeting ferroptosis-related pathways. Further study on ferroptosis-mediated cardiac injury can enhance our understanding of the pathophysiology of diabetic cardiovascular diseases and provide more potential therapeutic choices.

Identification of retinol dehydrogenase 10 as a shared biomarker for metabolic dysfunction-associated steatotic liver disease and type 2 diabetes mellitus

Background

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an independent risk factor for type 2 diabetes mellitus (T2DM), and its early identification and intervention offer opportunities for reversing diabetes mellitus.

Methods

In this study, we identified biomarkers for the MASLD dataset (GSE33814, GSE48452) and the T2DM dataset (GSE76895 and GSE89120) by bioinformatics analysis. Next, we constructed weighted gene co-expression network (WGCNA) for disease module analysis to screen out shared genes strongly associated with diseases. We also analyzed the enriched pathways of shared genes using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Next, hub gene validation was performed using the least absolute shrinkage and selection operator (LASSO) and receiver operating characteristic (ROC) curves. Finally, we used RT-qPCR, immunofluorescence, Western blotting and Elisa to validate hub gene expression in MASLD and T2DM mouse models.

Results

This analysis identified 20 genes shared by MASLD and T2DM that were enriched in the bile secretion, phototransduction, cancer, carbohydrate digestion and absorption, cholesterol/glycerol metabolism, and retinol metabolism. The LASSO algorithm and ROC curve identified Retinol Dehydrogenase 10 (RDH10) as the best diagnostic gene for MASLD and T2DM. Immunofluorescence and Western blot showed that RDH10 expression was reduced in the liver and pancreatic islets of MASLD and T2DM model mice. Similarly, serum levels of RDH10 were significantly lower in MASLD and T2DM model mice and humans than in controls.

Conclusion

Our study suggests that RDH10 is a common diagnostic marker for MASLD and T2DM and provides new research directions for the prevention and treatment of MASLD and T2DM.

Retinoic Acid Improves Vascular Endothelial Dysfunction by Inhibiting PI3K/AKT/YAP-mediated Ferroptosis in Diabetes Mellitus

BACKGROUND

Vascular endothelial dysfunction is the initial factor involved in cardiovascular injury in patients with diabetes. Retinoic acid is involved in improving vascular complications with diabetes, but its protective mechanism is still unclear. This study aimed to evaluate the effect and mechanism of All-trans Retinoic Acid (ATRA) on endothelial dysfunction induced by diabetes.

METHODS

In the present study, streptozotocin (STZ)-induced diabetic rats and high glucose (HG)-induced human umbilical vein endothelial cells (HUVECs) were observed, and the effects of ATRA on HG-induced endothelial dysfunction and ferroptosis were evaluated.

RESULTS

ATRA treatment improved impaired vasorelaxation in diabetic aortas in an endothelium-dependent manner, and this effect was accompanied by an increase in the NO concentration and eNOS expression. Ferroptosis, characterized by lipid peroxidation and iron overload induced by HG, was improved by ATRA administration, and a ferroptosis inhibitor (ferrostatin-1, Fer-1) improved endothelial function to a similar extent as ATRA. In addition, the inactivation of phosphoinositol-3-kinase (PI3K)/protein kinases B (AKT) and Yes-associated Protein (YAP) nuclear localization induced by HG were reversed by ATRA administration. Vascular ring relaxation experiments showed that PI3K/AKT activation and YAP inhibition had similar effects on ferroptosis and endothelial function. However, the vasodilative effect of retinoic acid was affected by PI3K/AKT inhibition, and the inhibitory effects of ATRA on ferroptosis and the improvement of endothelial function were dependent on the retinoic acid receptor.

CONCLUSION

ATRA could improve vascular endothelial dysfunction by inhibiting PI3K/AKT/YAP-mediated ferroptosis induced by HG, which provides a new idea for the treatment of vascular lesions in diabetes.

SREBP1 induction mediates long-term statins therapy related myocardial lipid peroxidation and lipid deposition in TIIDM mice

Statins therapy is efficacious in diminishing the risk of major cardiovascular events in diabetic patients. However, our research has uncovered a correlation between the prolonged administration of statins and an elevated risk of myocardial dysfunction in patients with type II diabetes mellitus (TIIDM). Here, we report the induction of sterol regulatory element-binding protein 1 (SREBP1) activation, associated lipid peroxidation, and the consequent diabetic myocardial dysfunction after statin treatment and explored the underlying mechanisms. In db/db mice, we observed that 40 weeks atorvastatin (5 and 10 mg/kg) and rosuvastatin (20 mg/kg) administration exacerbated diabetic myocardial dysfunction by echocardiography and cardiomyocyte contractility assay, increased myocardial inflammation and fibrosis as shown by CD68, IL-1β, Masson's staining and Collagen1A1 immunohistochemistry (IHC) staining, increased respiratory exchange ratio (RER) by metabolic cage system assessment, exacerbated mitochondrial structural pathological changes by transmission electron microscopy (TEM) examination, increased deposition of lipid and glycogen by TEM, Oil-red and periodic acid-schiff stain (PAS) staining, which were corresponded with augmented levels of myocardial SREBP1 protein and lipid peroxidation marked by 4-hydroxynonenal (4-HNE) staining. Comparable myocardial fibrosis was also observed in KK-ay and low-dose streptozotocin (STZ)-induced TIIDM mice. Elevated SREBP1 levels were observed in the heart tissues from diabetic patients, which was positively correlated with their myocardial dysfunction. To elucidate the role of statin induced SREBP1 in lipid peroxidation and lipid deposition and related mechanism, we cultured neonatal mouse primary cardiomyocytes (NMPCs) and treated them with atorvastatin (10 μM, 24 h), tracing with [U-13C]-glucose and evaluating for SREBP1 expression and localization. We found that statin treatment elevated de novo lipogenesis (DNL) and the levels of SREBP1 cleavage-activating protein (SCAP), reduced the interaction of SCAP with insulin-induced gene 1 (Insig1), and enhance SCAP/SREBP1 translocation to the Golgi, which facilitate SREBP1 cleavage leading to its nuclear trans-localization and activation in NMPCs. Ultimately, SREBP1 knockdown or l-carnitine mitigated long-term statins therapy induced lipid peroxidation and myocardial fibrosis in low-dose STZ treated SREBP1+/- mice and l-carnitine treated db/db mice. In conclusion, we demonstrated that statin therapy may augment DNL by activating SREBP1, resulting in myocardial lipid peroxidation and lipid deposition.

Expression, Purification, and Bioinformatic Prediction of Mycobacterium tuberculosis Rv0439c as a Potential NADP+-Retinol Dehydrogenase

Although the genome of Mycobacterium tuberculosis (Mtb) H37Rv, the causative agent of tuberculosis, has been repeatedly annotated and updated, a range of proteins from this human pathogen have unknown functions. Mtb Rv0439c, a member of the short-chain dehydrogenase/reductases superfamily, has yet to be cloned and characterized, and its function remains unclear. In this work, we present for the first time the optimized expression and purification of this enzyme, as well as bioinformatic analysis to unveil its potential coenzyme and substrate. Optimized expression in Escherichia coli yielded soluble Rv0439c, while certain tag fusions resulted in insolubility. Sequence and docking analyses strongly suggested that Rv0439c has a clear preference for NADP+, with Arg53 being a key residue that confers coenzyme specificity. Furthermore, functional prediction using CLEAN and DEEPre servers suggested that this protein is a potential NADP+-retinol dehydrogenase (EC No. 1.1.1.300) in retinol metabolism, and this was supported by a BLASTp search and docking studies. Collectively, our findings provide a solid basis for future functional characterization and structural studies of Rv0439c, which will contribute to enhanced understanding of Mtb biology.

Ferroptosis in diabetic cardiomyopathy: from its mechanisms to therapeutic strategies

Diabetic cardiomyopathy (DCM) is defined as structural and functional cardiac abnormalities in diabetes, and cardiomyocyte death is the terminal event of DCM. Ferroptosis is iron-dependent oxidative cell death. Evidence has indicated that iron overload and ferroptosis play important roles in the pathogenesis of DCM. Mitochondria, an important organelle in iron homeostasis and ROS production, play a crucial role in cardiomyocyte ferroptosis in diabetes. Studies have shown some anti-diabetic medicines, plant extracts, and ferroptosis inhibitors might improve DCM by alleviating ferroptosis. In this review, we systematically reviewed the evidence of ferroptosis in DCM. Anti-ferroptosis might be a promising therapeutic strategy for the treatment of DCM.

Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects

Iron, an essential mineral in the body, is involved in numerous physiological processes, making the maintenance of iron homeostasis crucial for overall health. Both iron overload and deficiency can cause various disorders and human diseases. Ferroptosis, a form of cell death dependent on iron, is characterized by the extensive peroxidation of lipids. Unlike other kinds of classical unprogrammed cell death, ferroptosis is primarily linked to disruptions in iron metabolism, lipid peroxidation, and antioxidant system imbalance. Ferroptosis is regulated through transcription, translation, and post-translational modifications, which affect cellular sensitivity to ferroptosis. Over the past decade or so, numerous diseases have been linked to ferroptosis as part of their etiology, including cancers, metabolic disorders, autoimmune diseases, central nervous system diseases, cardiovascular diseases, and musculoskeletal diseases. Ferroptosis-related proteins have become attractive targets for many major human diseases that are currently incurable, and some ferroptosis regulators have shown therapeutic effects in clinical trials although further validation of their clinical potential is needed. Therefore, in-depth analysis of ferroptosis and its potential molecular mechanisms in human diseases may offer additional strategies for clinical prevention and treatment. In this review, we discuss the physiological significance of iron homeostasis in the body, the potential contribution of ferroptosis to the etiology and development of human diseases, along with the evidence supporting targeting ferroptosis as a therapeutic approach. Importantly, we evaluate recent potential therapeutic targets and promising interventions, providing guidance for future targeted treatment therapies against human diseases.

Cardiomyocyte LGR6 alleviates ferroptosis in diabetic cardiomyopathy via regulating mitochondrial biogenesis

AIMS

The majority of people with diabetes are susceptible to cardiac dysfunction and heart failure, and conventional drug therapy cannot correct the progression of diabetic cardiomyopathy. We assessed the potential role and therapeutic value of LGR6 (G protein-coupled receptor containing leucine-rich repeats 6) in diabetic cardiomyopathy.

METHODS AND RESULTS

Type 2 diabetes models were established using high-fat diet/streptozotocin-induced diabetes in mice. LGR6 knockout mice were generated. Recombinant adeno-associated virus serotype 9 carrying LGR6 under the cardiac troponin T promoter was injected into diabetic mice. Cardiomyocytes incubated with high glucose (HG) were used to imitate diabetic cardiomyopathy in vitro. The molecular mechanism was explored through RNA sequencing and a chromatin immunoprecipitation assay. We found that LGR6 expression was upregulated in diabetic hearts and HL1 cardiomyocytes treated with HG. The LGR6 knockout aggravated, but cardiomyocyte-specific LGR6 overexpression ameliorated, cardiac dysfunction and remodeling in diabetic mice. Mechanistically, in vivo and in vitro experiments revealed that LGR6 deletion aggravated, whereas LGR6 overexpression alleviated, ferroptosis and disrupted mitochondrial biogenesis by regulating STAT3/Pgc1a signaling. STAT3 inhibition and Pgc1a activation abrogated LGR6 knockout-induced mitochondrial dysfunction and ferroptosis in diabetic mice. In addition, LGR6 activation by recombinant RSPO3 treatment ameliorated cardiac dysfunction, ferroptosis and mitochondrial dysfunction in diabetic mice.

CONCLUSIONS

We identified a previously undescribed signaling pathway of the LGR6-STAT3-Pgc1a axis that plays a critical role in ferroptosis and mitochondrial disorders during diabetic cardiomyopathy and provides an option for treatment of diabetic hearts.

Regulatory mechanisms of Capillaria hepatica infection on Brandt's Vole (Lasiopodomys brandtii) population

Parasite infection not only triggers the immune response of the host but also potentially affects the reproductive status, thereby influencing the population size. Therefore, understanding the impact of parasite infection on host immune and reproductive systems has long been an important issue in ecological research. To address this, we conducted field surveys (2021-2023) to investigate Capillaria hepatica infection status in Brandt's vole (Lasiopodomys brandtii) and performed controlled experiments in semi-natural enclosures and indoor laboratories. The results showed a negative correlation between the population size of Brandt's vole and the infection rate. To further explore the regulatory mechanisms, transcriptomic and proteomic analyses were performed on the infected BALB/c mice. The study found that post-infection with Capillaria hepatica, up-regulated genes and proteins in the mice liver were primarily associated with immune functions, while down-regulated genes and proteins were related to metabolic functions such as retinol metabolism. Through validation experiments supplementing retinol to the host infected with Capillaria hepatica, it was found that infection with Capillaria hepatica leads to a decrease in systemic available retinol levels, disrupting the expression of the hypothalamic-pituitary-gonadal (HPG) axis hormones, affecting the expression of CYP17A1, thereby regulating testosterone secretion related to spermatogenesis. This process results in abnormal spermatogenesis in the testes, thereby impacting the reproductive capacity of mice. This suggests that Capillaria hepatica regulates resource allocation in hosts, striking a "trade-off" between reproduction and survival, thereby exerting control over population size. These discoveries are crucial for comprehending the interaction between Capillaria hepatica and hosts, as well as their impacts on host reproduction and immune systems, and provide a scientific basis for controlling the transmission of Capillaria hepatica.

Lysophosphatidylcholine trigger myocardial injury in diabetic cardiomyopathy via the TLR4/ZNF480/AP-1/NF-kB pathway

Background

Diabetic cardiomyopathy (DC), a frequent complication of type 2 diabetes mellitus (T2DM), is mainly associated with severe adverse outcomes. Previous research has highlighted the role of Lysophosphatidylcholine (LPC) in inducing myocardial injury; however, the specific mechanisms through which LPC mediate such injury in DC remain elusive. The existing knowledge gap underscores the need for additional clarification. Consequently, this study aimed to explore the impact and underlying mechanisms of LPC on myocardial injury in DC.

Methods

A total of 55 patients diagnosed with T2DM and 62 healthy controls were involved. A combination of 16s rRNA sequencing, metabolomic analysis, transcriptomic RNA-sequencing (RNA-seq), and whole exome sequencing (WES) was performed on fecal and peripheral blood samples collected from the participants. Following this, correlation analysis was carried out, and the results were further validated through the mouse model of T2DM.

Results

Four LPC variants distinguishing T2DM patients from healthy controls were identified, all of which were upregulated in T2DM patients. Specifically, Lysopc (16:0, 2 N isoform) and LPC (16:0) exhibited a positive correlation with nuclear factor kappa B subunit 2 (NFKB2) and a negative correlation with Zinc finger protein 480 (ZNF480) Furthermore, the expression levels of Toll-like receptor 4 (TLR4), c-Jun, c-Fos, and NFKB2 were upregulated in the peripheral blood of T2DM patients and in the myocardial tissue of T2DM mice, whereas ZNF480 expression level was downregulated. Lastly, myocardial injury was identified in T2DM mice.

Conclusions

The results indicated that LPC could induce myocardial injury in DC through the TLR4/ZNF480/AP-1/NF-kB pathway, providing a precise target for the clinical diagnosis and treatment of DC.

Histone acetyltransferase Kat2a regulates ferroptosis via enhancing Tfrc and Hmox1 expression in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a prevalent myocardial microvascular complication of the myocardium with a complex pathogenesis. Investigating the pathogenesis of DCM can significantly contribute to enhancing its prevention and treatment strategies. Our study revealed an upregulation of lysine acetyltransferase 2 A (Kat2a) expression in DCM, accompanied by a decrease in N6-methyladenosine (m6A) modified Kat2a mRNA levels. Our study revealed an upregulation of lysine acetyltransferase 2 A (Kat2a) expression in DCM, accompanied by a decrease in N6-methyladenosine (m6A) modified Kat2a mRNA levels. Functionally, inhibition of Kat2a effectively ameliorated high glucose-induced cardiomyocyte injury both in vitro and in vivo by suppressing ferroptosis. Mechanistically, Demethylase alkB homolog 5 (Alkbh5) was found to reduce m6A methylation levels on Kat2a mRNA, leading to its upregulation. YTH domain family 2 (Ythdf2) played a crucial role as an m6A reader protein mediating the degradation of Kat2a mRNA. Furthermore, Kat2a promoted ferroptosis by increasing Tfrc and Hmox1 expression via enhancing the enrichment of H3K27ac and H3K9ac on their promoter regions. In conclusion, our findings unveil a novel role for the Kat2a-ferroptosis axis in DCM pathogenesis, providing valuable insights for potential clinical interventions.

Exploring the molecular biology of ischemic cardiomyopathy based on ferroptosis‑related genes

Ischemic cardiomyopathy (ICM) is a serious cardiac disease with a very high mortality rate worldwide, which causes myocardial ischemia and hypoxia as the main damage. Further understanding of the underlying pathological processes of cardiomyocyte injury is key to the development of cardioprotective strategies. Ferroptosis is an iron-dependent form of regulated cell death characterized by the accumulation of lipid hydroperoxides to lethal levels, resulting in oxidative damage to the cell membrane. The current understanding of the role and regulation of ferroptosis in ICM is still limited, especially in the absence of evidence from large-scale transcriptomic data. Through comprehensive bioinformatics analysis of human ICM transcriptome data obtained from the Gene Expression Omnibus database, the present study identified differentially expressed ferroptosis-related genes (DEFRGs) in ICM. Subsequently, their potential biological mechanisms and cross-talk were analyzed, and hub genes were identified by constructing protein-protein interaction networks. Ferroptosis features such as reactive oxygen species generation, changes in ferroptosis marker proteins, iron ion aggregation and lipid oxidation, were identified in the H9c2 anoxic reoxygenation injury model. Finally, the diagnostic ability of Gap junction alpha-1 (GJA1), Solute carrier family 40 member 1 (SLC40A1), Alpha-synuclein (SNCA) were identified through receiver operating characteristic curves and the expression of DEFRGs was verified in an in vitro model. Furthermore, potential drugs (retinoic acid) that could regulate ICM ferroptosis were predicted based on key DEFRGs. The present article presents new insights into the role of ferroptosis in ICM, investigating the regulatory role of ferroptosis in the pathological process of ICM and advocating for ferroptosis as a potential novel therapeutic target for ICM based on evidence from the ICM transcriptome.

Ferroptosis: A New Mechanism in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DC) is a pathophysiologic condition caused by diabetes mellitus (DM) in the absence of coronary artery disease, valvular heart disease, and hypertension that can lead to heart failure (HF), manifesting itself in the early stages with left ventricular hypertrophy and diastolic dysfunction, with marked HF and decreased systolic function in the later stages. There is still a lack of direct evidence to prove the exact existence of DC. Ferroptosis is a novel form of cell death characterized by reactive oxygen species (ROS) accumulation and lipid peroxidation. Several cell and animal studies have shown that ferroptosis is closely related to DC progression. This review systematically summarizes the related pathogenic mechanisms of ferroptosis in DC, including the reduction of cardiac RDH10 induced ferroptosis in DC cardiomyocytes which mediated by retinol metabolism disorders; CD36 overexpression caused lipid deposition and decreased GPX4 expression in DC cardiomyocytes, leading to the development of ferroptosis; Nrf2 mediated iron overload and lipid peroxidation in DC cardiomyocytes and promoted ferroptosis; lncRNA-ZFAS1 as a ceRNA, combined with miR-150-5p to inhibit CCND2 expression in DC cardiomyocytes, thereby triggering ferroptosis.

Upregulation of NF-κB by USP24 aggravates ferroptosis in diabetic cardiomyopathy

BACKGROUND

Recent investigations have proposed a potential causal association between the occurrence of ferroptosis, nuclear factor kappa B (NF-κB) and ubiquitin-specific protease 24 (USP24). Nevertheless, the mechanism of USP24 and NF-κB regulation of ferroptosis in the context of diabetic cardiomyopathy (DCM) remain unclear.

METHODS

In this study, a high-fat diet and a streptozotocin-induced mouse DCM model were established, and high glucose and palmitic acid treatment of H9c2 cells and neonatal mouse primary cardiomyocytes (NMPCs) was used as an in vitro DCM models. Utilizing both the in vivo and in vitro DCM models, we assessed of USP24, NF-κB, and ferroptosis levels, and explored the relationship among them.

RESULTS

In in vivo and in vitro DCM models, increased expression of USP24, NF-κB, phosphorylated NF-κB (p-NF-κB) and fatty acid-CoA ligase 4 (FACL4) were detected, along with accumulated iron, as well as reduced ferritin heavy chain 1 (FTH1), solute carrier family 7 member 11 (SLC7A11) and antioxidant capacity. Knockdown of USP24 resulted in a reduction of NF-κB levels, while knockdown of NF-κB did not lead to a decrease in USP24 expression. Moreover, in H9c2 cells, knockdown of USP24 and NF-κB separately resulted in reduced levels of FACL4, increased levels of SLC7A11 and FTH1, as well as improved antioxidant capacity and cell viability. In shUSP24 knockdown H9c2 cells, administration of phorbol 12-myristate 13-acetate (PMA) activated NF-κB, subsequently reversing the previously observed effect caused by USP24 knockdown.

CONCLUSIONS

These findings show that USP24 upregulates NF-κB to promote ferroptosis in DCM.

Current progress of ferroptosis in cardiovascular diseases

Ferroptosis, a newly recognized form of nonapoptotic regulated cell death, is characterized by iron-dependent lipid peroxidation. Biological processes, such as iron metabolism, lipid peroxidation, and amino acid metabolism, are involved in the process of ferroptosis. However, the related molecular mechanism of ferroptosis has not yet been completely clarified, and specific and sensitive biomarkers for ferroptosis need to be explored. Recently, studies have revealed that ferroptosis probably causes or exacerbates the progress of cardiovascular diseases, and could be the potential therapeutic target for cardiovascular diseases. In this review, we summarize the molecular mechanisms regulating ferroptosis, inducers or inhibitors of ferroptosis, and the current progresses of ferroptosis in cardiovascular diseases. Furthermore, we discuss the emerging challenges and future perspectives, which may provide novel insights into the treatment of cardiovascular diseases.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.

Retinol intake is associated with the risk of chronic kidney disease in individuals with type 2 diabetes mellitus: results from NHANES

The aim of this study was to investigate the potential association between retinol intake and the risk of chronic kidney disease (CKD) in individuals with type 2 diabetes mellitus (T2DM). The study included individuals diagnosed with T2DM between 2009 and 2018 from the NHANES database. Demographic and laboratory test data were collected for these individuals, as well as information on CKD diagnosis. Logistic regression models were utilized to estimate the relationship between different retinol intakes and the risk of CKD in patients with T2DM. A total of 3988 patients were included in the study. The mean prevalence of CKD in the T2DM population in the United States from 2009 to 2018 was 36.98 (0.02)%. Multivariate logistic regression analysis revealed a 26% decrease in the incidence of CKD in individuals with higher retinol intake compared to those with lower retinol intake in T2DM (OR = 0.74; 95% CI 0.56-0.98). Furthermore, an increase in retinol intake per 1-standard deviation (SD) was associated with a 16% decreased risk of the incidence of CKD (OR = 0.84; 95% CI 0.72-0.97). Lower retinol intake is an independent risk factor for the onset of CKD in patients with T2DM, and augmenting moderate quantities of retinol confers potential nephroprotective advantages.