Lipid metabolism reprogramming in cardiac fibrosis

GSTM1 suppresses cardiac fibrosis post-myocardial infarction through inhibiting lipid peroxidation and ferroptosis

BACKGROUND

Cardiac fibrosis following myocardial infarction (MI) drives adverse ventricular remodeling and heart failure, with cardiac fibroblasts (CFs) playing a central role. GSTM1 is an important member of the glutathione S-transferase (GSTs) family, which plays an important role in maintaining cell homeostasis and detoxification. This study investigated the role and mechanism of GSTM1 in post-MI fibrosis.

METHODS

Multi-omics approaches (proteomics/scRNA-seq) identified GSTM1 as a dysregulated target in post-MI fibroblasts. Using a murine coronary ligation model, we assessed GSTM1 dynamics via molecular profiling, such as Western blotting, immunofluorescence, and real-time quantitative polymerase chain reaction. AAV9-mediated cardiac-specific GSTM1 overexpression was achieved through systemic delivery. In vitro studies employed transforming growth factor-β (TGF-β)-stimulated primary fibroblasts with siRNA/plasmid interventions. Mechanistic insights were derived from transcriptomics and lipid peroxidation assays.

RESULTS

The expression of GSTM1 in mouse CFs after MI was significantly down-regulated at both transcriptional and protein levels. In human dilated cardiomyopathy (DCM) patients with severe heart failure, GSTM1 expression was decreased alongside aggravated fibrosis. Overexpression of GSTM1 in post-MI mice improved cardiac function, while significantly reducing infarct size and fibrosis compared with the control group. In vitro models demonstrated that GSTM1 markedly attenuated collagen secretion and activation of fibroblasts, as well as suppressed their proliferation and migration. Further studies revealed that GSTM1 overexpression significantly inhibited the generation of intracellular and mitochondrial reactive oxygen species (ROS) under pathological conditions, suggesting that GSTM1 exerts an antioxidative stress effect in post-infarction fibroblasts. Further investigation of molecular mechanisms indicated that GSTM1 may suppress the initiation and progression of fibrosis by modulating lipid metabolism and ferroptosis-related pathways. Overexpression of GSTM1 significantly reduced lipid peroxidation and free ferrous iron levels in fibroblasts and mitochondria, markedly decreased ferroptosis-related indicators, and alleviated oxidative lipid levels [such as 12-hydroxyeicosapentaenoic acid (HEPE) and 9-, 10-dihydroxy octadecenoic acid (DHOME)] under fibrotic conditions. GSTM1 enhanced the phosphorylation of STAT3, thereby upregulating the downstream expression of glutathione peroxidase 4 (GPX4), reducing ROS production, and mitigating fibroblast activation and phenotypic transformation by inhibiting lipid peroxidation.

CONCLUSIONS

This study identifies GSTM1 as a key inhibitor of fibroblast activation and cardiac fibrosis, highlighting its ability to target ferroptosis through redox regulation. AAV-mediated GSTM1 therapy demonstrates significant therapeutic potential for improving outcomes post-MI.

Hesperidin improves cardiac fibrosis induced by β-adrenergic activation through modulation of gut microbiota

Cardiac fibrosis is a prevalent characteristic of various cardiovascular diseases and poses a significant global health challenge. Recent research has established a robust correlation between gut microbiota and cardiovascular diseases. Hesperidin has been shown to possess cardioprotective properties to some extent. Furthermore, studies suggest that hesperidin may enhance overall health by regulating intestinal flora. However, there is a lack of reports regarding the effects of hesperidin on cardiac fibrosis. This study aimed to investigate the mechanisms by which hesperidin ameliorates cardiac fibrosis through the regulation of gut microbiota and associated metabolites. Cardiac fibrosis was induced in C57BL/6 mice via subcutaneous injection of isoproterenol (5 mg/kg per day) for a duration of 7 days. Echocardiography was used to assess cardiac function, while Masson staining, western blot analysis, and real-time polymerase chain reaction were used to evaluate fibrosis-related indicators. Changes in gut microbiota were analyzed through 16S ribosomal RNA gene sequencing. Our findings indicate that hesperidin significantly mitigates cardiac fibrosis in mice. These beneficial effects are associated with improvements in the dysbiosis of intestinal microbiota observed in fibrotic mouse models. The involvement of gut microbiota in cardiac fibrosis was further corroborated by administering hesperidin therapy to mice depleted of gut microbiota. To our knowledge, this study provides the first evidence that the modulation of gut microbiota by hesperidin contributes to improved outcomes in cardiac fibrosis. The use of traditional Chinese medicine to modulate gut microbiota presents a promising strategy for the treatment of cardiac fibrosis. SIGNIFICANCE STATEMENT: The work is extremely interesting because it acts on a frontier of science that relates the influence of the intestinal microbiota with human physiological systems and associated pathologies. This study provides the first evidence that the modulation of gut microbiota by hesperidin contributes to improved outcomes in cardiac fibrosis.

Inhibition of high glucose-induced cardiac fibroblast activation: an effective treatment for diabetic cardiomyopathy using Chinese herbal medicine

Diabetic cardiomyopathy (DCM) is one of the common diabetic microangiopathy in clinical practice. In the early stage of the disease, there are no obvious clinical symptoms. In the middle and late stages, MF, arrhythmia, and even heart failure may occur, affecting the life and health of patients. MF, as one of the pathological features of DCM at the end stage, is the key factor of poor prognosis leading to ventricular wall stiffness and heart failure, which affects the clinical process and outcome of patients. The development of MF in a high glucose environment involves multiple complex fibrogenic pathways that work together to activate fibroblasts, thereby promoting MF. Indeed, aberrant activation of cardiac fibroblasts (CFs) is a key factor in MF. Therefore, inhibiting the activation of CFs may become a new strategy for the treatment of DCM. Previous studies have shown that Chinese herbal medicine (CHM) has potential in the treatment of DCM. In this review, we first introduced the physiology and function of CFs and discussed the conditions for the pathological activation of CFs in the process of diabetes, and then systematically summarized the effects of CHM on the activation of CFs by controlling the production of advanced glycosylation end products, oxidative stress and inflammation. This review will illustrate the potential of CHM to inhibit the activation of CFs and provide new ideas for the treatment of DCM.

The protective effects of liraglutide in reducing lipid droplets accumulation and myocardial fibrosis in diabetic cardiomyopathy

BACKGROUND

Diabetes is a primary contributor to diabetic cardiomyopathy (DbCM), which is marked by metabolic imbalances such as elevated blood glucose and lipid levels, leading to significant structural and functional alterations in the myocardium. Elevated free fatty acids (FFAs) and hyperglycemia play critical roles in DbCM development, with FFAs inducing insulin resistance in cardiomyocytes and promoting lipid accumulation, resulting in oxidative stress and fibrosis. Current research suggests that glucagon-like peptide-1 (GLP-1) receptor agonists may effectively mitigate DbCM, although an effective treatment for this condition remains elusive, and the precise mechanisms of this protective effect are not fully understood.

METHODS

In this study, we aimed to replicate diabetic glucolipotoxic conditions by treating differentiated H9c2 cells with high glucose and free fatty acids. Additionally, a diabetic cardiomyopathy model was induced in mice through high-fat diets. Both in vitro and in vivo models were used to investigate the protective effects of liraglutide on cardiomyocytes and elucidate its underlying molecular mechanisms.

RESULTS

Our findings indicate that liraglutide significantly reduces lipid droplet (LD) formation and myocardial fibrosis, as evidenced by decreased expression of fibrosis markers, including TGF-β1 and collagen types I and III. Liraglutide also enhanced AMP-activated protein kinase (AMPK) activation, which improved mitochondrial function, increased antioxidant gene expression, enhanced insulin signaling, and reduced oxidative stress.

CONCLUSIONS

These results demonstrate the potential therapeutic role of liraglutide in managing diabetes-related cardiac complications, offering a comprehensive approach to improving cardiac outcomes in patients with diabetes.

Association between allostatic load and cardiac structural and functional abnormalities in young adults with serious mental disorders

OBJECTIVE

Allostatic load refers to the pathophysiological consequences of uncompensated adaptation to chronic stress. Few studies have investigated the effect of allostatic load on cardiac health in patients with serious mental disorders (SMDs), a population at high risk of cardiac mortality. Herein we evaluated associations between allostatic load and cardiac structure and function in young adults with SMDs.

METHOD

A total of 106 participants aged younger than 45 years underwent echocardiographic study, blood biochemistry examination, and blood cell count analysis. Echocardiographic imaging was conducted in accordance with recommendations of the American Society of Echocardiography and European Association of Cardiovascular Imaging. Allostatic load index was calculated using 15 measures representing cardiovascular, metabolic, and inflammatory or oxidative stress markers.

RESULTS

The SMD group exhibited a significantly higher allostatic load index than did control (Cohen's d = 0.59). Additionally, they exhibited a greater left ventricular relative wall thickness (LVRWT, Cohen's d = 0.39) and a less favorable mitral valve E/A ratio (Cohen's d = 0.31), left ventricular ejection fraction (Cohen's d = 0.51), and global longitudinal strain (Cohen's d = 0.71). After demographic and clinical characteristics were adjusted for, multiple linear regression revealed that allostatic load index was positively associated with LVRWT (β = 0.255) and negatively associated with mitral valve E/A ratio (β = -0.247) in the SMD group.

CONCLUSIONS

This is the first study to suggest that allostatic load may play a critical role in accelerated adverse cardiac remodeling among young patients with SMDs. Future studies should elucidate the underlying mechanisms.

Epigenetic regulation of diverse regulated cell death modalities in cardiovascular disease: Insights into necroptosis, pyroptosis, ferroptosis, and cuproptosis

Cell death constitutes a critical component of the pathophysiology of cardiovascular diseases. A growing array of non-apoptotic forms of regulated cell death (RCD)-such as necroptosis, ferroptosis, pyroptosis, and cuproptosis-has been identified and is intimately linked to various cardiovascular conditions. These forms of RCD are governed by genetically programmed mechanisms within the cell, with epigenetic modifications being a common and crucial regulatory method. Such modifications include DNA methylation, RNA methylation, histone methylation, histone acetylation, and non-coding RNAs. This review recaps the roles of DNA methylation, RNA methylation, histone modifications, and non-coding RNAs in cardiovascular diseases, as well as the mechanisms by which epigenetic modifications regulate key proteins involved in cell death. Furthermore, we systematically catalog the existing epigenetic pharmacological agents targeting novel forms of RCD and their mechanisms of action in cardiovascular diseases. This article aims to underscore the pivotal role of epigenetic modifications in precisely regulating specific pathways of novel RCD in cardiovascular diseases, thus offering potential new therapeutic avenues that may prove more effective and safer than traditional treatments.

Enhanced lipid metabolism reprogramming in CHF rats through IL-6-mediated cardiac glial cell modulation by digilanid C and electroacupuncture stimulation combination

Background

Cardiac lipid metabolism reprogramming is recognized as a critical pathological factor in the progression of chronic heart failure (CHF). The therapeutic potential of digilanid C and electroacupuncture stimulation (ES) in enhancing lipid metabolism and cardiac function has been established. However, the optimal synergistic regulatory strategies of these interventions on cardiac lipid metabolism have yet to be elucidated.

Methods

This study aimed to comprehensively evaluate the impact of a digilanid C-ES combination on cardiac steatosis remodeling in CHF. Assessments were conducted across various dimensions, including myocardial oxygen consumption, mitochondrial function, and lipid metabolism. Additionally, we sought to uncover the underlying neuromolecular mechanisms.

Results

Our findings, at both molecular and morphological levels, indicated that the synergistic application of digilanid C and ES significantly inhibited myocardial fibrosis and steatosis. This combination therapy facilitated the repair of cardiac neuro-vascular uncoupling and induced a reprogramming of lipid metabolism. Notably, the digilanid C-ES combination ameliorated cardiomyocyte apoptosis and enhanced mitochondrial biogenesis in CHF, leading to a restructured energy supply pattern. Cardiac immunofluorescence analyses revealed the aggregation of cardiac glial cells (CGCs) at sites of abnormal neurovascular coupling, a response to cardiac lipid degeneration. This was accompanied by a marked reduction in the abnormally elevated expression of interleukin 6 (IL-6) and glutamatergic signaling, which correlated with the severity of cardiac steatosis and the aberrant activation of CGCs. The combined therapy was found to activate the Janus kinase 1 (JAK1)/signal transducer and activator of transcription 3 (STAT3) pathway, effectively attenuated lipid accumulation and over-recruitment of CGCs and deprivation of glutamatergic nerves.

Conclusion

These findings underscore the potential of digilanid C and ES combination therapy as a novel approach to modulate the complex interplay between neurovascular dynamics and metabolic dysregulation in CHF.

Emodin nanocapsules inhibit acute pancreatitis by regulating lipid metabolic reprogramming in macrophage polarization

BACKGROUND

Emodin is a chemical compound found in traditional Chinese herbs. It possesses anti-inflammatory and many other pharmacological effects. Our previous study showed that emodin significantly alleviates the inflammation effect of severe acute pancreatitis (SAP). However, its poor solubility, high toxicity and limited pancreas retention time hinder its clinical application.

PURPOSE

We aimed to prepare emodin nanocapsules with improved bioavailability to achieve the controlled release of emodin by targeting macrophages. Further, the mechanism of mannose-conjugated chitosan-coated lipid nanocapsules loaded with emodin (M-CS-E-LNC) in the treatment of SAP was explored.

METHODS

M-CS-E-LNC were prepared by the phase inversion method with slight modification. The expression of inflammation mediators and the anti-inflammation efficacy of M-CS-E-LNC were examined by ELISA, IHC and IF in macrophage cells and LPS-induced SAP mice. IVIS spectrum imaging and HPLC were applied to explore the controlled release of M-CS-E-LNC in the pancreas. LC-MS/MS was performed for lipidomics analysis of macrophages. Moreover, a vector-based short hairpin RNA (shRNA) method was used to silence CTP1 gene expression in macrophage cells.

RESULTS

The levels of inflammatory mediators in macrophages were markedly decreased after treatment with M-CS-E-LNC. The same anti-inflammation effects were detected in SAP mouse through the analysis of serum levels of amylase, TNF-α and IL-6. Importantly, M-CS-E-LNC allowed the emodin to selectively accumulate at pancreas and gastrointestinal tissues, thus exhibiting a targeted release. Mechanistically, the M-CS-E-LNC treatment group showed up-regulated expression of the carnitine palmitoyltransferase 1 (CPT1) protein which promoted intracellular long-chain fatty acid transport, thereby promoting the M2 phenotype polarization of macrophages.

CONCLUSION

M-CS-E-LNC exhibited significantly improved bioavailability and water solubility, which translated to greater therapeutic effects on macrophage polarization. Our findings also demonstrate, for the first time, that CPT1 may be a new therapeutic target for SAP treatment.

3D-MPEA: A Graph Attention Model-Guided Computational Approach for Annotating Unknown Metabolites in Interactomics via Mass Spectrometry-Focused Multilayer Molecular Networking

The spectral matching strategy of MS2 fragment spectrograms serves as a ubiquitous method for compound characterization within the matrix. Nevertheless, challenges arise due to the deficiency of distinctions in spectra across instruments caused by coelution peak-derived fragments and incompleteness of the current spectral reference database, leading to dilemma of multidimensional omics annotation. The graph attention model embedded with long short-term memory was proposed as an optimized approach involving integrating similar MS2 spectra into molecular networks according to the isotopic ion peak cluster spacing features to collapse diverse ion species and expand the spectral reference library, which efficiently evaluated the substance capture capacity to 123.1% than classic substance perception tactics. The versatility and utility of the established annotation procedure were showcased in a study on the stimulation of pork mediated by 2,2-bis(4-hydroxyphenyl)propane and enabled the global metabolite annotation from knowns to unknowns at metabolite-lipid-protein level. On the spectra for which in silico extended spectral library search provided a group truth, 83.5-117.1% accuracy surpassed 1.2-14.3% precision after manual validation. β-Ala-His dipeptidase was first evidenced as the critical node related to the transformation of α-helical (36.57 to 35.74%) to random coil (41.53 to 42.36%) mediated by 2,2-bis(4-hydroxyphenyl)propane, ultimately triggering an augment of catalytic performance, inducing a series of oxidative stress, and further intervening in the availability of animal-derived substrates. The integration of ionic fragment feature networks and long short-term memory models allows the effective annotation of recurrent unknowns in organisms and the deciphering of unacquainted matter in multiomics.

Cardiac fibrogenesis: an immuno-metabolic perspective

Cardiac fibrosis is a major and complex pathophysiological process that ultimately culminates in cardiac dysfunction and heart failure. This phenomenon includes not only the replacement of the damaged tissue by a fibrotic scar produced by activated fibroblasts/myofibroblasts but also a spatiotemporal alteration of the structural, biochemical, and biomechanical parameters in the ventricular wall, eliciting a reactive remodeling process. Though mechanical stress, post-infarct homeostatic imbalances, and neurohormonal activation are classically attributed to cardiac fibrosis, emerging evidence that supports the roles of immune system modulation, inflammation, and metabolic dysregulation in the initiation and progression of cardiac fibrogenesis has been reported. Adaptive changes, immune cell phenoconversions, and metabolic shifts in the cardiac nonmyocyte population provide initial protection, but persistent altered metabolic demand eventually contributes to adverse remodeling of the heart. Altered energy metabolism, mitochondrial dysfunction, various immune cells, immune mediators, and cross-talks between the immune cells and cardiomyocytes play crucial roles in orchestrating the transdifferentiation of fibroblasts and ensuing fibrotic remodeling of the heart. Manipulation of the metabolic plasticity, fibroblast-myofibroblast transition, and modulation of the immune response may hold promise for favorably modulating the fibrotic response following different cardiovascular pathological processes. Although the immunologic and metabolic perspectives of fibrosis in the heart are being reported in the literature, they lack a comprehensive sketch bridging these two arenas and illustrating the synchrony between them. This review aims to provide a comprehensive overview of the intricate relationship between different cardiac immune cells and metabolic pathways as well as summarizes the current understanding of the involvement of immune-metabolic pathways in cardiac fibrosis and attempts to identify some of the previously unaddressed questions that require further investigation. Moreover, the potential therapeutic strategies and emerging pharmacological interventions, including immune and metabolic modulators, that show promise in preventing or attenuating cardiac fibrosis and restoring cardiac function will be discussed.