Metrnl ameliorates diabetic cardiomyopathy via inactivation of cGAS/STING signaling dependent on LKB1/AMPK/ULK1-mediated autophagy

Leptin attenuates diabetic cardiomyopathy-induced cardiac remodeling via regulating cGAS/STING signaling and Opa1-mediated mitochondrial fusion

PURPOSE

This investigation seeks to elucidate the contribution of leptin to the pathogenesis of diabetic cardiomyopathy (DCM).

METHODS

Mice were rendered diabetic through the administration of streptozotocin (STZ). Leptin was delivered via subcutaneously implanted osmotic pumps. Assessments of cardiac performance, hypertrophy, and fibrosis were conducted using echocardiography, Hematoxylin and Eosin (H&E), Wheat Germ Agglutinin (WGA), and Masson trichrome staining. Myocardial apoptosis and oxidative stress were quantified through TUNEL assay and biochemical markers of oxidative stress, including Malondialdehyde (MDA), 4-Hydroxynonenal (4-HNE), and 3-Nitrotyrosine (3NT). Mitochondrial structure was examined using Transmission Electron Microscopy (TEM). Primary neonatal cardiomyocytes were subjected to high glucose (HG) conditions. The fluorescent indicators MitoTracker Green and MitoSOX Red were employed to evaluate mitochondrial morphology and function within the cardiomyocytes.

RESULTS

Mice with diabetes displayed marked cardiac hypertrophy and fibrosis, as indicated by H&E, WGA, and Masson staining. The administration of leptin significantly mitigated the cardiac pathological manifestations in diabetic mice. Leptin increased the expression of Opa1 and enhanced mitochondrial fusion and function in cardiomyocytes exposed to HG. The cGAS/STING signaling pathway may serve as a pivotal intermediary for leptin to facilitate Opa1-driven mitochondrial fusion.

CONCLUSIONS

Leptin appears to safeguard against hyperglycemia-induced mitochondrial oxidative damage and DCM by modulating the cGAS/STING signaling cascade and Opa1-mediated mitochondrial fusion. These results propose that leptin could be a promising agent for promoting mitochondrial fusion and preventing diabetes-associated cardiac pathologies.

Saikosaponin A targets HDAC6 to inhibit Mycobacterium tuberculosis-induced macrophage Pyroptosis via autophagy-mediated NLRP3 inflammasome inactivation

BACKGROUND

Mycobacterium tuberculosis (Mtb) is among the oldest and most resilient human pathogens, remaining a major global public health threat. Its characteristic pathological features include granuloma formation and a systemic inflammatory response, primarily resulting from dysregulated host immune reactions. Therefore, host-directed therapy (HDT) is considered an important complement to conventional anti-TB treatment.

PURPOSE

This study sought to examine the inhibitory effects of Saikosaponin A (SSA), an active compound extracted from Bupleurum, on Mtb-induced macrophage pyroptosis, as well as the underlying molecular mechanisms.

METHODS

The effects of SSA on key molecules involved in pyroptosis and autophagy were examined in an in vitro model of Mtb-infected macrophages using Western blotting, ELISA, co-immunoprecipitation, and immunofluorescence assays. The function of histone deacetylase 6 (HDAC6) in modulating autophagy and pyroptosis in Mtb-infected macrophages was elucidated using gene silencing techniques. The SSA-HDAC6 interaction was validated using drug target identification methods such as molecular docking and site-directed mutagenesis. Furthermore, we established an in vivo model of lipopolysaccharide-induced pulmonary inflammation via intraperitoneal injection to assess whether SSA exerts a protective effect by inhibiting pyroptosis.

RESULTS

In vitro experiments demonstrated that SSA enhanced autophagy to inactivate the NLRP3 inflammasome, thereby inhibiting Mtb-induced pyroptosis. Mechanistically, SSA interacted with HDAC6 and effectively suppressed its enzymatic activity. This interaction enabled SSA to target HDAC6, thereby modulating autophagy via the AMPK/mTOR/ULK1 axis, ultimately attenuating Mtb-induced pyroptosis in macrophages. Furthermore, in vivo experiments revealed that SSA regulated the acetylation of α-tubulin (Lys40), alleviating inflammatory lung injury in mice.

CONCLUSION

SSA targets HDAC6 and exerts an immunomodulatory effect, highlighting its potential as a promising novel host-directed anti-tuberculosis agent.

Independent and synergistic effects of extreme heat and NO2 pollution on diabetic nephropathy in a type II diabetes mouse model

Extreme heat and traffic-related air pollution (TRAP) have been linked to worsening chronic health disorders, however, their combined effects on diabetic nephropathy (DN) are little understood. Type II diabetic mice were exposed to heat (40 °C) and NO2 (5 ppm) separately for 4 h per day over 6 weeks to investigate the synergistic effects on the progression of DN. We found that exposure to high temperature and NO2 elevated blood glucose levels and exacerbated histopathological changes. Additionally, there were increased oxidation indicators (ROS, MDA, 8-OHdG) and decreased antioxidant indicators (CAT, SOD, GSH-PX), along with elevated inflammation markers (TNF-α, IL-1β, IL-6). The expressions of transient receptor potential (TRP) ion channels (TRPV1, TRPV4, TRPA1, TRPM2) were also upregulated. Our findings suggest that simultaneous exposure to high temperature and NO2 impairs metabolic and autophagy pathways. Exposure to both high temperature and NO2 produces a synergistic effect, leading to more severe damage than exposure to either factor individually. This resulted in increased expression of APOA1, P62, and p-mTOR/mTOR while decreasing the expression of p-AMPKα/AMPKα and LC3-II/I. This disruption promoted the progression of DN. In contrast, capsazepine (CZP) reduced TRP expression, inflammatory markers, oxidative stress, metabolic and autophagy disorders, thereby mitigating renal damage and alleviating the progression of diabetic nephropathy. Our study provides some potential strategies for early prevention and effective reduction of DN.

cGAS-STING targeting offers a novel therapeutic paradigm in cardiovascular diseases

Cyclic GMP/AMP (cGAMP) synthase (cGAS), along with the endoplasmic reticulum (ER)-associated stimulator of interferon genes (STING), are crucial elements of the type 1 interferon response. cGAS senses microbial DNA and self-DNA, labeling cGAS-STING as a crucial mechanism in autoimmunity, sterile inflammatory responses, and cellular senescence. However, chronic and aberrant activation of the cGAS/STING axis results in inflammatory and autoimmune diseases. cGAS-STING has emerged as a vital mechanism driving inflammation-related diseases, including cardiovascular diseases (CVDs). Insights into the biology of the cGAS-STING pathway have enabled the discovery of small-molecule agents which have the potential to inhibit the cGAS-STING axis in many human diseases. In this review, we first outline the principal components of the cGAS-STING signaling cascade. From such we discuss recent research that highlights general mechanisms by which cGAS-STING contributes to CVDs. Then, we summarize a list of bioactive small-molecule compounds which modulate the cGAS-STING axis, reviewing their potential clinical applications. Finally, we discuss key limitations of this new proposed therapeutic approach and provide possible techniques to overcome them.These review highlights a novel groundbreaking therapeutic possibilities through targeting cGAS-STING in CVDs.

Cellular crosstalk mediated by Meteorin-like regulating hepatic stellate cell activation during hepatic fibrosis

Liver fibrosis is characterized by an excessive accumulation of extracellular matrix (ECM), primarily produced by activated hepatic stellate cells (HSCs). The activation of HSCs is influenced by paracrine signaling interactions among various liver cell types, but molecular mechanisms remain to be elucidated. Secretory Meteorin-like (Metrnl) can effectively ameliorate fulminant hepatitis. However, little is known about its role in liver fibrosis. In our study, we found that hepatic Metrnl mRNA transcripts and protein expression were significantly downregulated in patients and mouse models of hepatic fibrosis. Hepatocyte-specific and global knockout of Metrnl exacerbated CCl4-induced liver fibrosis. In contrast, the administration recombinant Metrnl or AAV-Metrnl overexpression markedly ameliorated CCl4-induced liver fibrosis in mice, suggesting a protective role for Metrnl. Mechanistically, hepatocyte-derived Metrnl not only influences the activation of HSCs through paracrine signaling but also modulates the release of the fibrogenic cytokine PDGFB via the transcription factor EGR1, thereby regulating PDGFB/PDGFRβ signaling to affect HSC activation. Furthermore, Metrnl absence in hepatocytes and HSCs leads to the downregulation of the E3 ubiquitin ligase HECW2, inhibiting K48-linked ubiquitination of FN and preventing its proteasomal degradation, thus promoting FN secretion from HSCs. These effects contribute to ECM deposition and the activation of HSCs, ultimately exacerbating liver fibrosis. Collectively, our study reveals Metrnl as a novel regulator of liver fibrosis that mediates communication between hepatocytes and HSCs, indicating its potential as a therapeutic target for liver fibrosis. The identification of Metrnl as a critical player in the pathogenesis of hepatic fibrosis underscores the importance of understanding cellular crosstalk in the progression of liver disease.

Inhibition of ULK1 attenuates ferroptosis-mediated cardiac hypertrophy via HMGA2/METTL14/SLC7A11 axis in mice

UNC-51-like kinase 1 (ULK1), a primary serine/threonine kinase, is implicated in diverse pathophysiological processes. Previous findings have linked ULK1-dependent autophagy to cardiac hypertrophy. Our study further explored the functional role and molecular mechanisms of ULK1 in non-autophagic signaling pathways. Notably, ULK1 expression was significantly elevated in both transverse aortic constriction (TAC)-induced hypertrophic mouse hearts and Angiotensin II (Ang II)-treated cardiomyocytes, suggesting an increased sensitivity to hypertrophic stimuli potentially mediated by ULK1-induced ferroptosis in hypertrophic cardiomyocytes. Treatment with the ferroptosis inhibitor ferrostatin-1 (Fer-1) effectively reduced ULK1-induced cardiomyocyte hypertrophy and ferroptosis. Proteomic analysis identified the upregulation of transcription factor high mobility group A2 (HMGA2) as a key mechanism in this ferroptotic process. Elevated HMGA2 levels exacerbated ferroptosis, evidenced by increased cell death, lipid peroxidation, ROS production, and reduced GPX4 expression. Furthermore, HMGA2 was shown to promote cardiomyocyte ferroptosis via binding to methyltransferase-like 14 (METTL14), which in turn enhanced ferroptosis in cardiomyocytes through solute carrier family 7 member 11 (SLC7A11) m6A modification. In vivo, a delivery system using neutrophil membrane (NM)-coated mesoporous silica nanoparticles (MSN) was developed to inhibit cardiac hypertrophy, underscoring the therapeutic potential of targeting ULK1. Overall, this study demonstrates that ULK1 promotes cardiac hypertrophy through HMGA2/METTL14/SLC7A11 axis-mediated cardiomyocyte ferroptosis, suggesting a novel therapeutic approach for cardiac hypertrophy.

Meteorin-β: A Novel Biomarker and Therapeutic Target on Its Way to the Regulation of Human Diseases

The novel secreted protein Meteorin-β (Metrnβ) is a homologous protein of the neurotrophic regulator Meteorin, which is widely expressed in the skin, mucous membranes, and white adipose tissue upon stimulation by a variety of inflammatory mediators, including cytokines and chemokines, while, at the same time Metrnβ may also regulate the expression of these cytokines and chemokines. As a small secreted protein with low tissue specificity, Metrnβ plays vital roles in energy metabolism, insulin sensitivity regulation, neurodevelopment, white fat browning, and inflammatory response. Specifically, Metrnβ may act as an adipokine, myokine, neurotrophic factor, and cytokine, thereby being involved in the pathological and physiological processes of various human diseases, including metabolic, autoimmune and infectious/allergic diseases, and certain types of tumors. This review aims to systematically introduce the current research progress on Metrnβ, including its expression and distribution profiles, biological functions, and immunomodulatory roles in the process of human diseases. Additionally, we also discuss its potential as a biomarker, as well as a therapeutic/preventive agent for human diseases.

Roles of HSP70 in autophagic protection of cardiomyocytes induced by heat acclimation: A review

In conditions of extreme high temperature, the heart is susceptible to injury induced by heat stress, which can manifest as myocardial ischemia and hypoxia, cardiomyocyte apoptosis, oxidative damage, and inflammatory responses. The normal function of cardiomyocytes is contingent upon the maintenance of protein homeostasis, and dysregulation of protein homeostasis is the underlying cause of myocardial structural damage. Autophagy and Heat Shock Protein 70 (Hsp70) play pivotal roles in regulating cellular protein quality and mitigating stress injury. Heat acclimation has been shown to induce Hsp70 expression and provide cardiomyocyte protection. However, the mechanism by which Hsp70 mediates cardiomyocyte autophagy to exert protective effects has not been fully elucidated. The objective of this review is to synthesize the existing literature on the effects of Hsp70 on autophagy during heat exposure, to explore the potential mechanisms by which Hsp70 regulates myocardial autophagy and the molecular pathways it involves, and to provide a theoretical basis for future therapeutic strategies for cardiac diseases.

DNA-RNA hybrids in inflammation: sources, immune response, and therapeutic implications

Cytoplasmic DNA-RNA hybrids are emerging as important immunogenic nucleic acids, that were previously underappreciated. DNA-RNA hybrids, formed during cellular processes like transcription and replication, or by exogenous pathogens, are recognized by pattern recognition receptors (PRRs), including cGAS, DDX41, and TLR9, which trigger immune responses. Post-translational modifications (PTMs) including ubiquitination, phosphorylation, acetylation, and palmitoylation regulate the activity of PRRs and downstream signaling molecules, fine-tuning the immune response. Targeting enzymes involved in DNA-RNA hybrid metabolism and PTMs regulation offers therapeutic potential for inflammatory diseases. Herein, we discuss the sources, immune response, and therapeutic implications of DNA-RNA hybrids in inflammation, highlighting the significance of DNA-RNA hybrids as potential targets for the treatment of inflammation.

Meteorin-like protein (Metrnl): a key exerkine in exercise-mediated cardiovascular health

CONTEXT

Cardiovascular diseases (CVDs) remain a leading global cause of mortality, necessitating non‑pharmacological interventions such as exercise. Meteorin‑like protein (Metrnl), an exercise‑induced myokine and adipokine, has emerged as a critical mediator of exercise‑mediated cardiovascular benefits, though its specific mechanisms and clinical implications remain underexplored.

OBJECTIVE

This review synthesizes current evidence on Metrnl's role as a key exerkine in cardiovascular health, focusing on its exercise‑induced regulatory mechanisms, tissue‑specific effects, and therapeutic potential for CVD management.

METHODS

A comprehensive analysis of preclinical and clinical studies was conducted, encompassing molecular, metabolic, and anti‑inflammatory pathways linked to Metrnl. Literature from PubMed, Scopus, and Web of Science was systematically reviewed to evaluate Metrnl's role in exercise‑mediated cardiovascular adaptations.

RESULTS

Exercise‑induced Metrnl enhances endothelial function, vascular remodeling, and metabolic regulation via AMPK, PPARγ, and KIT receptor signaling. It promotes glucose/lipid metabolism, angiogenesis, and anti‑inflammatory responses, reducing atherosclerotic risks and improving cardiac repair post‑infarction. Clinically, Metrnl levels correlate with CVD severity, acting as a biomarker for risk stratification. Acute exercise elevates Metrnl, while chronic training effects vary by modality and population. Paradoxically, elevated plasma Metrnl in acute cardiac events predicts adverse outcomes, whereas reduced levels in chronic conditions (e.g., diabetes, heart failure) reflect metabolic dysregulation.

DISCUSSION

Metrnl bridges exercise benefits to cardiovascular health through inter‑organ crosstalk, yet discrepancies exist in its chronic exercise‑mediated regulation. Its dual role as a protective mediator and stress‑responsive biomarker underscores context‑dependent interpretations. Unresolved questions include receptor specificity, tissue autonomy, and therapeutic delivery strategies.

CONCLUSION

Metrnl is a pivotal exerkine with promising diagnostic and therapeutic potential for CVDs. Translating its exercise‑mediated benefits into clinical applications requires further human trials to validate mechanisms and optimize interventions. Harnessing Metrnl could revolutionize strategies for CVD prevention and rehabilitation, leveraging exercise's molecular advantages.

Meteorin-like protein plasma levels are associated with worse outcomes in de novo heart failure

BACKGROUND AND AIMS

Meteorin-like protein (Metrnl) has been recently suggested as a new adipokine with protective cardiovascular effects. Its circulating levels in patients seem to be associated with heart failure (HF), although with contradictory results. Our aim was to ascertain whether this adipokine could estimate the prognosis of HF in de novo HF (DNHF) patients.

METHODS

Metrnl plasma levels of 400 patients hospitalized with DNHF (55% of patients with HF with reduced ejection fraction, 17.3% HF with mid-range ejection fraction, 27.8% HF with preserved ejection fraction) were measured by enzyme-linked immunosorbent assay. We performed both sex-pooled and sex-specific analyses. A 12-month follow-up was conducted, during which clinical outcomes such as all-cause mortality, cardiovascular death and re-hospitalization due to HF were collected.

RESULTS

After a 12-month follow up, higher plasma Metrnl levels were associated with an increased risk for all-cause death and cardiovascular death after adjusting by sex, age, LVEF, hypertension, diabetes, ischemic aetiology, chronic renal failure, NT-proBNP and troponin (hazard ratio [HR] = 1.003, 95% confidence interval [CI] = 1.000-1.005; p-value<.05 and HR = 1.004, 95% CI = 1.001-1.007, p-value<.05, respectively). In line with this, DNHF patients with increased levels of circulating Metrnl had a higher number of occurrences of cardiovascular events. Regarding Metrnl associations with parameters implicated in the development and progression of HF, we found that Metrnl circulating levels were positively correlated with age (r = .322, p-value<.0001), NT-proBNP (r = .281, p-value<.0001) and with the renal dysfunction markers urea (r = .322, p-value<.0001) and creatinine (r = .353, p-value<.0001) and higher in women than men (473.7 [385.9-594.0] pg/mL vs. 428.7 [349.1-561.3] pg/mL, p-value<.006). Finally, concerning the subtype of HF, Metrnl plasma levels were higher in HF with preserved ejection fraction.

CONCLUSION

Patients with higher Metrnl levels have a worse prognosis in DNHF. Our results reinforce the association of Metrnl plasma levels with HF progression and outcomes.

Exploring the therapeutic potential of HAPC in COVID-19-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is one of the critical complications of coronavirus disease 2019 (COVID-19), which significantly impacts the survival of patients.

PURPOSE

In this study, we screened COVID-19-related target genes and identified and optimized potential drugs targeting these genes for the treatment of COVID-19.

STUDY DESIGN

In this study, bioinformatic analyses were conducted and subsequently identified and optimized potential drugs targeting these genes for the treatment of COVID-19 were carried out.

METHODS

Firstly, we analyzed the targets gene in patients with COVID-19 using single-cell data analysis. We performed structural modifications on Chicoric acid (CA) and combined it with hyaluronic acid to enhance the targeted activity towards Cluster of differentiation 44 (CD44). Poly (sodium-p styrenesulfonate) (PSS) was used to form a PSS-coated CA+hyaluronic acid nanocomplex (HA-P). Subsequently, Lactobacillus murinus conidia cell wall (CW) was encapsulated to prepare PSS-coated CA + hyaluronic acid + Lactobacillus murinus conidia cell wall (HAPC) nanocomplexes.

RESULTS

The expression of APPL1 expression in macrophage of COVID-19 patients was up-regulation. CA was found to bind to the APPL1 protein and inhibit its ubiquitination. HAPC effectively targeted ALI through the highly efficient interaction between CD44 and Hyaluronic acid (HA). HAPC alleviated the symptoms of ALI and restored epithelial function in mice with ALI. HAPC induced the Adaptor protein containing a pH domain, PTB domain and leucine zipper motif 1 (APPL1)/ liver kinase B1 (LKB1)/ AMP-activated protein kinase (AMPK) pathway by inactivating the NOD - like receptor protein 3 (NLRP3) pathway in ALI. CA interacted with the APPL1 protein and prevented its ubiquitination. HAPC facilitated the interaction between APPL1 and LKB1 to induce the AMPK/NLRP3 pathway. It promoted the formation of LKB1 at GLU-67, ARG-72, ARG-314, ASP-316, and GLN-312 and APPL1 at ARG-106, ASP-115, LYS-124, ASN-119, and GLU-120.

CONCLUSION

Altogether, HAPC nanocomplexes exerted anti-inflammatory effects on ALI by promoting the interaction between APPL1 and LKB1 to induce the AMPK/NLRP3 pathway, and may be one new therapeutic strategie for ALI.

Cardiomyocyte-specific deletion of STING improves cardiac function, glucose homeostasis, and wound healing in diabetic mice

AIMS

The present study aimed to investigate the effects and underling mechanisms of cardiomyocyte-specific STING knockout on cardiac function and wound healing in diabetes.

MATERIALS AND METHODS

In this study, type 2 diabetes was induced in cardiomyocyte-specific STING knockout mice using a combination of a high-fat diet and streptozotocin. Cardiac function and remodeling were assessed by echocardiography and histopathological analysis. Glucose homeostasis was evaluated through insulin sensitivity tests and intraperitoneal glucose tolerance tests. Wound healing was quantified by measuring the wound area in diabetic mice.

KEY FINDINGS

The results demonstrated that STING deletion in cardiomyocytes improved cardiac function in diabetic mice, which was accompanied by enhanced insulin sensitivity and improved glucose tolerance. Furthermore, the deletion of STING partially mitigated mitochondrial dysfunction in the myocardium. STING knockout in cardiomyocytes also facilitated angiogenesis and wound healing in diabetic mice.

SIGNIFICANCE

Our findings suggest that cardiomyocyte-specific STING deletion enhances cardiac function, glucose homeostasis, and wound healing, indicating that targeting STING in the heart may serve as a promising therapeutic strategy for managing diabetes mellitus.

Therapeutic Targeting of Decr1 Ameliorates Cardiomyopathy by Suppressing Mitochondrial Fatty Acid Oxidation in Diabetic Mice

BACKGROUND

A significant increase in mitochondrial fatty acid oxidation (FAO) is now increasingly recognized as one of the metabolic alterations in diabetic cardiomyopathy (DCM). However, the molecular mechanisms underlying mitochondrial FAO impairment in DCM remain to be fully elucidated.

METHODS

A type 2 diabetes (T2D) mouse model was established by a combination of high-fat diet (HFD) and streptozotocin (STZ) injection. Neonatal rat cardiomyocytes were treated with high glucose (HG) and palmitic acid (HP) to simulate diabetic cardiac injury. Gain- and loss-of-function approaches and RNA sequencing were utilized to investigate the role and mechanism of 2,4-dienoyl-CoA reductase 1 (Decr1) in DCM.

RESULTS

By integrating the genomic data available in the Gene Expression Omnibus (GEO) with DCM rodents, we found that the transcriptional level of Decr1 was consistently upregulated in DCM (+255% for diabetic heart, p < 0.0001; +281% for diabetic cells, p < 0.0001). Cardiomyocytes-specific knockdown of Decr1 preserved cardiac function (+41% for EF, p < 0.0001; +24% for FS, p = 0.0052), inhibited cardiac hypertrophy (-34%, p < 0.0001), fibrosis (-69%, p < 0.0001), apoptosis (-56%, p < 0.0001) and oxidative damage (-59%, p < 0.0001) in DCM mice, while cardiomyocytes-specific overexpression of Decr1 aggravated DCM (-28% for EF, p = 0.0347; -17% for FS, p = 0.0014). Deletion of Decr1 prevented high glucose/palmitate (HG/HP)-induced hypertrophy (-22%, p = 0.0006), mitochondrial dysfunction and apoptosis (-74%, p < 0.0001) in cultured cardiomyocytes. Furthermore, RNA sequencing and functional analysis showed that Decr1 interacted with and upregulated pyruvate dehydrogenase kinase 4 (PDK4) in injured cardiomyocytes, and overexpression of PDK4 eliminated the benefits of Decr1 downregulation in DCM (-20% for EF, p = 0.0071; -28% for FS, p = 0.0022). Mechanistically, PDK4 acted as a kinase that induced phosphorylation and mitochondrial translocation of HDAC3. In the mitochondria, HDAC3 mediated the deacetylation of dehydrogenase trifunctional multienzyme complex α subunit (HADHA), contributing to excessive mitochondrial FAO and subsequent cardiac injury. From a screening of 256 natural products, we identified Atranorin and Kurarinone as potential inhibitors of Decr1, both demonstrating protective effects against DCM (Atranorin, +21% for EF, p = 0.0134; +24% for FS, p = 0.0006; Kurarinone, +20% for EF, p = 0.0183; +27% for FS, p = 0.0001).

CONCLUSIONS

Our study delineates a molecular mechanism by which Decr1 potentiated higher mitochondrial lipid oxidation and cardiac damage by enhancing HADHA deacetylation through the PDK4/HDAC3 signalling pathway.

Metrnl ameliorates myocardial ischemia-reperfusion injury by activating AMPK-mediated M2 macrophage polarization

BACKGROUND

Meteorin-like hormone (Metrnl) is prominently expressed in activated M2 macrophages and has demonstrated potential therapeutic effects in a range of cardiovascular diseases by modulating inflammatory responses. Nevertheless, its precise role and the underlying mechanisms in myocardial ischemia/reperfusion injury (MI/RI) are not fully understood. This study examined whether Metrnl can mitigate MI/RI through the AMPK-mediated polarization of M2 macrophages.

METHODS

In vivo, adeno-associated virus 9 containing the F4/80 promoter (AAV9-F4/80) was utilized to overexpress Metrnl in mouse cardiac macrophages before MI/RI surgery. In vitro, mouse bone marrow-derived macrophages (BMDMs) were treated with recombinant protein Metrnl, and the human cardiomyocyte cell line AC16 was subjected to hypoxia/reoxygenation (H/R) after co-culture with the supernatant of these macrophages. Cardiac function was assessed via echocardiography, H&E staining, and Evans blue-TTC staining. Inflammatory infiltration was evaluated by RT-qPCR and ELISA, apoptosis by Western blotting and TUNEL staining, and macrophage polarization by immunofluorescence staining and flow cytometry.

RESULTS

In vivo, Metrnl overexpression in cardiac macrophages significantly attenuated MI/RI, as evidenced by reduced myocardial infarct size, enhancement of cardiac function, diminished inflammatory cell infiltration, and decreased cardiomyocyte apoptosis. Furthermore, Metrnl overexpression promoted M1 to M2 macrophage polarization. In vitro, BMDMs treated with Metrnl shifted towards M2 polarization, characterized by decreased expression of inflammatory cytokines (IL-1β, MCP-1, TNF-α) and increased expression of the anti-inflammatory cytokine IL-10. Additionally, supernatant from Metrnl-treated macrophages protected AC16 cells from apoptosis under H/R conditions, as evidenced by decreased BAX expression and increased BCL-2 expression. However, these effects of Metrnl were inhibited by the AMPK inhibitor Compound C.

CONCLUSIONS

Metrnl alleviates MI/RI by activating AMPK-mediated M2 macrophage polarization to attenuate inflammatory response and cardiomyocyte apoptosis. This study highlights the therapeutic potential of Metrnl in MI/RI, and identifies it as a promising target for the treatment of ischemic heart disease.

Berberine and its derivatives: mechanisms of action in myocardial vascular endothelial injury - a review

Myocardial vascular endothelial injury serves as a crucial inducer of cardiovascular diseases. Mechanisms such as endoplasmic reticulum stress, apoptosis, inflammation, oxidative stress, autophagy, platelet dysfunction, and gut microbiota imbalance are intimately linked to this condition. Berberine and its derivatives have demonstrated potential in modulating these mechanisms. This article reviews the pathogenesis of endothelial injury in myocardial vessels, the pharmacological effects of berberine and its derivatives, particularly their interactions with targets implicated in vascular endothelial injury. Furthermore, it discusses clinical applications, methods to enhance bioavailability, and toxicity concerns, aiming to lay a foundation for the development of BBR as a therapeutic agent for cardiovascular diseases.

Specific muscle targeted delivery of miR-130a loaded lipid nanoparticles: a novel approach to inhibit lipid accumulation in skeletal muscle and obesity

BACKGROUND

Skeletal muscle lipid deposition is a key manifestation of obesity, often accompanied by decreased exercise capacity and muscle atrophy. Skeletal muscle as the largest organ in the body, makes it challenges for designing targeted drug delivery systems. Lipid nanoparticles (LNPs) are widely used as a safe and efficient delivery carrier, there is limited research on LNPs that specifically target skeletal muscle.

RESULTS

A LNP designed with five specific receptor complements on its surface, which specifically targets skeletal muscle in vivo in mice, without off-target effects on other tissues and organs. MiR-130a, a regulator of PPARG, which is a key factor in skeletal muscle lipid deposition, was encapsulated with LNP (LNP@miR-130a). In high-fat diet (HFD) mice, LNP@miR-130a effectively reduced skeletal muscle lipid deposition, increased exercise activity and enhanced muscle mass. Interestingly, the myokines in skeletal muscle have also changed which may leading to reduce the adipose tissue weight and liver lipid deposition in HFD mice.

CONCLUSIONS

These results indicated LNP@miR-130a is a promising inhibitor of skeletal muscle lipid deposition and may help alleviate obesity. This study provides new insights for obesity treatment and lays foundation for the development of targeted skeletal muscle therapeutics.

Creatine promotes osteogenic differentiation of dental pulp stem cells via the AMPK-ULK1-autophagy axis

OBJECTIVE

We aimed to demonstrate the effects of creatine (Cr) on osteogenic differentiation (OD) in HDPSCs.

MATERIALS AND METHODS

HDPSCs were treated with Cr and an inhibitor of Cr transporter. The OD capacity was evaluated by detecting ALP staining and activity, alizarin red staining (ARS), as well as osteogenesis-related protein levels. Transcriptomic sequencing, western blotting, transmission electron microscopy, immunofluorescence staining, and autophagy-related protein marker detection were applied to illustrate the underlying mechanism. Furthermore, the impact of Cr on bone regeneration was investigated in vivo.

RESULTS

We found that 1 mm of Cr effectively enhanced the OD of HDPSCs. The creatine group displayed significantly increased AMPK phosphorylation, overexpressed autophagy-related proteins, enhanced OD, and mineralization capabilities. We also found that ULK1 is the downstream molecule through which AMPK induces cellular autophagy. In vivo results demonstrated that Cr could increase the new bone formation of periodontitis.

CONCLUSION

Our research discovered a new AMPK-ULK1-autophagy pathway through which Cr enhances OD in HDPSCs. Cr enhanced HDPSCs-mediated periodontal tissue regeneration in a periodontitis mouse model, providing a theoretical foundation for the study of bone repair in periodontitis.

Metrnl Ameliorates Ferroptosis in Model of Diabetic Foot Ulcer Through the Inhibition of Mitochondrial Damage via LKB1/AMPK Signaling

Diabetic foot ulcer (DFU) represents a severe complication of diabetes, mainly caused by peripheral vascular occlusion and infection, presenting significant clinical challenges in treatment and potentially resulting in gangrene, amputation, or even fatality. This study aimed to investigate the involvement and underlying mechanisms of Meteorin-like (Metrnl) in the pathogenic process of DFU. Mice underwent diabetes induction by streptozotocin, while human umbilical vein endothelial cells (HUVECs) were exposed to 5.5, 10, 20 or 40 mM glucose. HUVECs were transfected with negative or Metrnl or si-nc or si-Metrnl plasmids via Lipofectamine 2000. The expression of Metrnl was down-regulated in both patients and the murine model of DFU. Elevated glucose levels diminished Metrnl through enhanced Metrnl ubiquitination. The suppression of Metrnl exacerbated foot ulcer in the mouse model of DFU. Metrnl alleviated oxidative stress and ferroptosis in the DFU model by inhibiting mitochondrial damage. Metrnl induced liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK) signaling in the DFU model. LKB1 attenuated the effects of Metrnl on oxidative stress and ferroptosis in the DFU model.  The data cumulatively demonstrate that Metrnl ameliorates ferroptosis in the DFU model by inhibiting mitochondrial damage via LKB1/AMPK signaling, suggesting that targeting Metrnl may emerge as a potential preventive approach against ferroptosis of DFU or other diabetes.

Autophagy in High-Fat Diet and Streptozotocin-Induced Metabolic Cardiomyopathy: Mechanisms and Therapeutic Implications

Metabolic cardiomyopathy, encompassing diabetic and obese cardiomyopathy, is an escalating global health concern, driven by the rising prevalence of metabolic disorders such as insulin resistance, type 1 and type 2 diabetes, and obesity. These conditions induce structural and functional alterations in the heart, including left ventricular dysfunction, fibrosis, and ultimately heart failure, particularly in the presence of coronary artery disease or hypertension. Autophagy, a critical cellular process for maintaining cardiac homeostasis, is frequently disrupted in metabolic cardiomyopathy. This review explores the role of autophagy in the pathogenesis of high-fat diet (HFD) and streptozotocin (STZ)-induced metabolic cardiomyopathy, focusing on non-selective and selective autophagy pathways, including mitophagy, ER-phagy, and ferritinophagy. Key proteins and genes such as PINK1, Parkin, ULK1, AMPK, mTOR, ATG7, ATG5, Beclin-1, and miR-34a are central to the regulation of autophagy in metabolic cardiomyopathy. Dysregulated autophagic flux impairs mitochondrial function, promotes oxidative stress, and drives fibrosis in the heart. Additionally, selective autophagy processes such as lipophagy, regulated by PNPLA8, and ferritinophagy, modulated by NCOA4, play pivotal roles in lipid metabolism and iron homeostasis. Emerging therapeutic strategies targeting autophagy, including plant extracts (e.g., curcumin, dihydromyricetin), endogenous compounds (e.g., sirtuin 3, LC3), and lipid/glucose-lowering drugs, offer promising avenues for mitigating the effects of metabolic cardiomyopathy. Despite recent advances, the precise mechanisms underlying autophagy in this context remain poorly understood. A deeper understanding of autophagy's regulatory networks, particularly involving these critical genes and proteins, may lead to novel therapeutic approaches for treating metabolic cardiomyopathy.

Praeruptorin A screened by a ferrous ion probe inhibited DMT1 and ferroptosis to attenuate Doxorubicin-induced cardiomyopathy

Doxorubicin (DOX)-induced cardiomyopathy (DIC) greatly limits its clinical application of the anticancer drug. Therefore, there is an immediate necessity to undertake intervention studies to minimize DIC, encompassing the screening of regulatory compounds and delving into the underlying regulatory mechanisms. A growing body of research suggests that ferroptosis is an essential process in the development of DIC. Here, we demonstrated that DOX causes elevated iron levels in cardiomyocytes and mouse hearts, and leads to ferroptosis and cardiac insufficiency. Next, we performed high-throughput screening of a library of herbal small molecule compounds for novel compounds that inhibit ferroptosis, using Fe2+ levels as a screening index for DIC prevention and treatment drugs. We found that Praeruptorin A (PA) was able to reduce Fe2+ concentration in cardiomyocytes, inhibit ferroptosis, and alleviate DIC and cardiac dysfunction in mice. Concurrently, PA exhibits a synergistic effect with DOX in suppressing the proliferation of carcinoma of breast MCF-7 cell in nude mice. Mechanistically, we found that PA inhibited the expression of divalent metal transporter protein 1 (DMT1), suppressed Fe2+ overload in cardiomyocytes, and inhibited ferroptosis, thereby alleviating DIC. Our study demonstrated the feasibility of high-throughput screening targeting the Fe2+ concentration, and elucidated the role and mechanism of PA in alleviating DIC, which provides a new possibility.

The Stimulator of Interferon Genes Deficiency Attenuates Diabetic Myopathy Through Inhibiting NLRP3-Mediated Pyroptosis

BACKGROUND

Diabetic myopathy is characterized by the loss of skeletal muscle mass and function. NOD-like receptor family pyrin domain containing 3 (NLRP3)-mediated pyroptosis is a type of proinflammatory cell death, which can exacerbate significant muscle cell loss and adverse remodelling. The stimulator of interferon genes (STING) is an essential molecule involved in the regulation of inflammation and immune responses across various diseases. The regulatory mechanism by which STING affects muscle pyroptosis in diabetic myopathy remains unclear.

METHODS

STING-knockout and wild-type (WT) mice underwent intraperitoneal injection of streptozotocin (STZ). STING small interfering RNA (siRNA) was transfected into fully differentiated C2C12 myotubes prior to glucose treatment. Muscle function tests, body composition analysis, transmission electron microscopy, scanning electron microscopy, western blotting, immunofluorescence, immunohistochemistry, histology, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction were performed. Co-immunoprecipitation assays were employed to investigate the interaction between STING and NLRP3.

RESULTS

STING expression was elevated in the gastrocnemius muscle (GM) tissues of WT diabetic mice. STING-deficient diabetic mice exhibited pronounced hyperglycaemia accompanied by hypoinsulinaemia, with no significant difference compared with WT diabetic mice. However, STING-deficient diabetic mice demonstrated a significantly increased body weight and lean mass. A significant decrease in muscle weight, myofibrillar diameter and area, muscle function, and the expression of genes related to muscle atrophy (MuRF1, Atrogin1) were observed in WT diabetic mice, which was mitigated in STING-deficient diabetic mice. STING deficiency reduced the number of GSDMD-N formed pores and pyroptosis-related components (NLRP3, caspase-1, cle-caspase-1, GSDMD, and GSDMD-N) in the GM tissues and was associated with a reduction in inflammatory chemokines. Similar changes were observed in vitro with glucose-induced myotube atrophy and pyroptosis as seen in vivo. Activation of STING by the agonist diABZI exacerbated muscle atrophy and pyroptosis in C2C12 myotubes. Co-localization of STING and NLRP3 was observed, and the interaction between STING and NLRP3 was enhanced in GM tissues from WT diabetic mice. We also found that STING could activate NLRP3 dependent on its channel activity, which can be attenuated by treated with C53 (an inhibitor of STING's ion-channel function).

CONCLUSIONS

In conclusion, our results indicate that STING-induced activation of the NLRP3 inflammasome leads to pyroptosis, resulting in muscle atrophy and dysfunction. These findings not only elucidate the mechanism of STING-induced pyroptosis but also identify STING as a potential therapeutic target for diabetic myopathy.

Metrnl/C-KIT Axis Attenuates Early Brain Injury Following Subarachnoid Hemorrhage by Inhibiting Neuronal Ferroptosis

BACKGROUND AND PURPOSE

Ferroptosis is a distinct form of cell death characterized by iron-dependent lipid peroxidation and plays a crucial role in the early brain injury (EBI) following subarachnoid hemorrhage (SAH). As a newly discovered endogenous ligand for the C-KIT receptor tyrosine kinase, meteorin-like protein (Metrnl) exerts regulatory functions in oxidative stress and protects against various diseases. However, the specific role of the Metrnl/C-KIT axis in neuronal ferroptosis during EBI following SAH remains to be elucidated.

METHODS

Sprague Dawley rats were used to establish the SAH model through endovascular perforation. r-Metrnl was administered intranasally 1 h after SAH. Metrnl shRNA, C-KIT inhibitor ISCK03, AMPK inhibitor dorsomorphin, and Nrf2 inhibitor ML385 were administered intracerebroventricularly or intraperitoneally before r-Metrnl treatment to explore the underlying mechanisms. Neurobehavioral assessments, immunofluorescence, western blot, ELISA, Fluoro-Jade C staining, transmission electron microscopy, and Nissl staining were conducted to evaluate the effects. Additionally, primary neuron culture with hemoglobin (Hb) stimulation was used for in vitro studies.

RESULTS

Phosphorylated C-KIT and endogenous Metrnl levels were upregulated after SAH. Knockdown of Metrnl aggravated neurobehavioral deficits and neuronal ferroptosis, whereas r-Metrnl treatment showed a protective effect. Mechanistically, r-Metrnl significantly increased the protein levels of SLC7A11, GPX4, FTH, FSP1, and GSH, whereas it decreased the levels of ACSL4, 4HNE, and MDA in the ipsilateral hemisphere 24 h after SAH. Also, r-Metrnl reduced mitochondrial shrinkage, increased mitochondrial crista, and decreased membrane density. However, the beneficial effects of r-Metrnl were partially reversed by ISCK03, dorsomorphin, or ML385 treatment both in vivo and in vitro.

CONCLUSIONS

Our study demonstrated that r-Metrnl reduced neuronal ferroptosis and improved neurological outcomes after SAH by modulating the C-KIT/AMPK/Nrf2 signaling pathway.

Downregulated DKK2 may serve as a molecular mechanism of high-fat diet-induced myocardial injury via Wnt/β-catenin pathway

OBJECTIVE

High-fat diet could induce structural and functional disorders of the heart, but the underlying mechanism remains elusive. This study aimed to explore related mechanism of obesity cardiomyopathy.

METHODS

Obesity model was established by feeding rats with a high-fat diet, and H9c2 cells were stimulated with palmitic acid to mimic high-fat stimulation. Whole transcriptome analysis results showed that the expression of Dickkopf-2 (DKK2) in obesity cardiomyopathy group was significantly lower than that in control group and simple obesity group. Overexpression and knockdown of DKK2 was achieved by infection with lentivirus. Weight, blood glucose, lipids, blood pressure, and insulin, HE staining, Sirius red staining and echocardiography results were analyzed in rats at 8 and 16 weeks after various interventions. qRT-PCR and western blots were used to detect the expression of RNAs and proteins.

RESULTS

High-fat diet-induced obese rats presented with changes in serum lipid, insulin, and increases in myocardial inflammation and fibrosis. Protein and mRNA expression levels of DKK2 were significantly decreased in the obesity cardiomyopathy group compared with the obesity and control group. In vitro, knockdown of DKK2 activated β-catenin/Wnt3a pathway, while overexpress of DKK2 inhibited β-catenin/Wnt3a expression.

CONCLUSION

Activating DKK2 may serve as a novel therapeutic intervention option for obesity cardiomyopathy and obesity-related metabolic disorders, and future studies are needed to validate this hypothesis.

Study on the underlying mechanism of Huachansu Capsule induced cardiotoxicity of normal rat by integrating transcriptomics, metabolomics and network toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Huachansu Capsule (HCSc) is a simple enteric-coated capsule refined from the skin of the dried toad, a traditional medicinal herb. It has been used clinically for many years to treat a variety of malignant tumors with remarkable efficacy. To date, a number of main components of HCSc have been reported to be cardiotoxic, but the specific mechanism of cardiotoxicity is still unknown.

AIM OF THE STUDY

The aim of this study was to elucidate the possible cardiotoxic symptoms caused by high-doses of HCSc and to further reveal the complex mechanisms by which it causes cardiotoxicity.

MATERIALS AND METHODS

UPLC-Q-Exactive Orbitrap MS and network toxicology were used to identify and predict the potential toxic components, related signaling pathways. Then, we used acute and sub-acute toxicity experiments to reveal the apparent phenomenon of HCSc-induced cardiotoxicity. Finally, we combined transcriptomics and metabolomics to elucidate the potential mechanism of action, and verified the putative mechanism by molecular docking, RT-qPCR, and Western blot.

RESULTS

We found 8 toad bufadienolides components may be induced cardiac toxicity HCSc main toxic components. Through toxicity experiments, we found that high dose of HCSc could increase a variety of blood routine indexes, five cardiac enzymes, heart failure indexes (BNP), troponin (cTnI and cTnT), heart rate and the degree of heart tissue damage, while low-dose of HCSc had no such changes. In addition, by molecular docking, found that 8 kinds of main toxic components and cAMP, AMPK, IL1β, mTOR all can be a very good combination, especially in the cAMP. Meanwhile, RT-qPCR and Western blot results showed that HCSc could induce cardiotoxicity by regulating a variety of heart-related differential genes and activating the cAMP signaling pathway.

CONCLUSIONS

In this study, network toxicology, transcriptomics and metabolomics were used to elucidate the complex mechanism of possible cardiotoxicity induced by high-dose HCSc. Animal experiments, molecular docking, Western blot and RT-qPCR experiments were also used to verify the above mechanism. These findings will inform further mechanistic studies and provide theoretical support for its safe clinical application.

N6-methyladenosine modification of SPOP relieves ferroptosis and diabetic cardiomyopathy by enhancing ubiquitination of VDAC3

Understanding the pathogenesis of diabetic cardiomyopathy (DCM), a common microvascular complication affecting the heart, is crucial for identifying new therapeutic targets and intervention strategies for DCM. Our study revealed a significant downregulation in Speckle-type POZ protein (SPOP) expression in DCM, while the overexpression of SPOP improved DCM-induced myocardial dysfunction, injury, fibrosis, hypertrophy, and ferroptosis. Mechanistically, SPOP facilitated the degradation of voltage-dependent anion channel 3 (VDAC3) by enhancing its ubiquitination. M6A demethylase AlkB homolog 5 (ALKBH5) reduced the mRNA stability of SPOP by decreasing m6A modification in its 3'UTR. The m6A reader insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) enhanced the stability of SPOP mRNA through recognition of m6A-modified SPOP 3'UTR. Furthermore, ALKBH5 promoted ferroptosis by inhibiting SPOP-induced VDAC3 degradation, while IGF2BP2 inhibited ferroptosis via activation of SPOP-induced VDAC3 degradation in high glucose-treated neonatal mouse ventricular cardiomyocytes (NMVCs). Overall, our study has unveiled a novel role of SPOP in the pathogenesis of ferroptosis and DCM, thereby significantly advancing our understanding of the involvement of ferroptosis during the progression of DCM. Moreover, this discovery offers promising potential therapeutic interventions targeting DCM.

Metrnl and Cardiomyopathies: From Molecular Mechanisms to Therapeutic Insights

Cardiomyopathies, a diverse group of diseases affecting the heart muscle, continue to pose significant clinical challenges due to their complex aetiologies and limited treatment options targeting underlying genetic and molecular dysregulations. Emerging evidence indicates that Metrnl, a myokine, adipokine and cardiokine, plays a significant role in the pathogenesis of various cardiomyopathies. Therefore, the objective of this review is to examine the role and mechanism of Metrnl in various cardiomyopathies, with the expectation of providing new insights for the treatment of these diseases.

Ferritinophagy mediated by the AMPK/ULK1 pathway is involved in ferroptosis subsequent to ventilator-induced lung injury

Mechanical ventilation (MV) remains a cornerstone of critical care; however, its prolonged application can exacerbate lung injury, leading to ventilator-induced lung injury (VILI). Although previous studies have implicated ferroptosis in the pathogenesis of VILI, the underlying mechanisms remain unclear. This study investigated the roles of ferritinophagy in ferroptosis subsequent to VILI. Using C57BL/6J mice and MLE-12 cells, we established both in vivo and in vitro models of VILI and cyclic stretching (CS)-induced cellular injury. We assessed lung injury and the biomarkers of ferroptosis and ferritinophagy, after appropriate pretreatments. This study demonstrated that high tidal volumes (HTV) for 4 h enhanced the sensitivity to ferroptosis in both models, evidenced by increased intracellular iron levels, lipid peroxidation and cell death, which can be mitigated by ferrostatin-1 treatment. Notably, nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy contributed to ferroptosis in VILI. Inhibition of autophagy with 3-methyladenine or NCOA4 knockdown decreased intracellular Fe2+ levels and inhibited lipid peroxidation, thereby attenuating CS-induced lung injury. Furthermore, it has also been observed that the AMPK/ULK1 axis can trigger ferritinophagy in VILI. Collectively, our study indicated that MV can induce ferroptosis by promoting NCOA4-dependent ferritinophagy, which could be a novel therapeutic target for the prevention and treatment of VILI.

Swimming training attenuates doxorubicin induced cardiomyopathy by targeting the mir-17-3p/KEAP1/NRF2 axis

Doxorubicin (DOX), as a first-line anticancer drug, is widely used in the treatment of various cancers. However, its clinical application is restricted due to its severe cardiac toxicity. Previous studies have indicated exercise training can alleviate the DOX-induced cardiotoxicity (DIC), but the underlying mechanism remains unclear. Our research has discovered, post-exercise, an elevated expression level of mir-17-3p, but in DIC its level decreases. Therefore, we further studied the effect of exercise mir-17-3p axis on DIC. In vivo, we simulated DIC mouse model, followed by an intervention using swimming and adenovirus to inhibit mir-17-3p. We found that inhibition of mir-17-3p can weaken the protection of exercise against DIC, presenting as weakened heart function. Besides, the levels of Malondialdehyde and Fe2+ in the cardiac tissue increased, along with diminished glutathione peroxidase 4 and Solute Carrier Family 7 Member 11 levels, and a decline in the concentration of glutathione, causing an increase in ferroptosis. Moreover, in vitro, we used dual-luciferase assay to confirm that Kelch Like ECH Associated Protein 1 (KEAP1) can be a target gene of mir-17-3p. We used Keap1/NFE2 Like BZIP Transcription Factor 2 (NRF2) inhibitor brusatol and Stimulator of Interferon Response CGAMP Interactor 1 (STING) agonist SR-717 to verify the mir-17-3p/KEAP1 axis can affect the Cyclic GMP-AMP Synthase (CGAS)/STING pathway, leading to further ferroptosis in DIC. This manifested as a reduction in ferroptosis. In summary, our research suggests swimming training enhances the levels of mir-17-3p, thereby activating the KEAP1/NRF2 pathway, and weakening the CGAS/STING pathway, improving ferroptosis in DIC.

Autophagy and lysosomal dysfunction in diabetes and its complications

Autophagy is critical for energy homeostasis and the function of organelles such as endoplasmic reticulum (ER) and mitochondria. Dysregulated autophagy due to aging, environmental factors, or genetic predisposition can be an underlying cause of not only diabetes through β-cell dysfunction and metabolic inflammation, but also diabetic complications such as diabetic kidney diseases (DKDs). Dysfunction of lysosomes, effector organelles of autophagic degradation, due to metabolic stress or nutrients/metabolites accumulating in metabolic diseases is also emerging as a cause or aggravating element in diabetes and its complications. Here, we discuss the etiological role of dysregulated autophagy and lysosomal dysfunction in diabetes and a potential role of autophagy or lysosomal modulation as a new avenue for treatment of diabetes and its complications.

Recent advances associated with cardiometabolic remodeling in diabetes-induced heart failure

Diabetes mellitus (DM) is characterized by chronic hyperglycemia, and despite intensive glycemic control, the risk of heart failure in patients with diabetes remains high. Diabetes-induced heart failure (DHF) presents a unique metabolic challenge, driven by significant alterations in cardiac substrate metabolism, including increased reliance on fatty acid oxidation, reduced glucose utilization, and impaired mitochondrial function. These metabolic alterations lead to oxidative stress, lipotoxicity, and energy deficits, contributing to the progression of heart failure. Emerging research has identified novel mechanisms involved in the metabolic remodeling of diabetic hearts, such as autophagy dysregulation, epigenetic modifications, polyamine regulation, and branched-chain amino acid (BCAA) metabolism. These processes exacerbate mitochondrial dysfunction and metabolic inflexibility, further impairing cardiac function. Therapeutic interventions targeting these pathways-such as enhancing glucose oxidation, modulating fatty acid metabolism, and optimizing ketone body utilization-show promise in restoring metabolic homeostasis and improving cardiac outcomes. This review explores the key molecular mechanisms driving metabolic remodeling in diabetic hearts, highlights advanced methodologies, and presents the latest therapeutic strategies for mitigating the progression of DHF. Understanding these emerging pathways offers new opportunities to develop targeted therapies that address the root metabolic causes of heart failure in diabetes.

Matairesinol blunts adverse cardiac remodeling and heart failure induced by pressure overload by regulating Prdx1 and PI3K/AKT/FOXO1 signaling

BACKGROUND

Pathological cardiac remodeling is a critical process leading to heart failure, characterized primarily by inflammation and apoptosis. Matairesinol (Mat), a key chemical component of Podocarpus macrophyllus resin, exhibits a wide range of pharmacological activities, including anti-hydatid, antioxidant, antitumor, and anti-inflammatory effects.

PURPOSE

This study aims to investigate whether Matairesinol alleviate cardiac hypertrophy and remodeling caused by pressure overload and to elucidate its mechanism of action.

METHODS

An in vitro pressure loading model was established using neonatal rat cardiomyocytes treated with angiotensin Ⅱ, while an in vivo model was created using C57 mice subjected to transverse aortic constriction (TAC). To activate the PI3K/Akt/FoxO1 pathway, Ys-49 was employed. Moreover, small interfering RNA (siRNA) and short hairpin RNA (shRNA) were utilized to silence Prdx1 expression both in vitro and in vivo. Various techniques, including echocardiography, wheat germ agglutinin (WGA) staining, HE staining, PSR staining, and Masson trichrome staining, were used to assess cardiac function, cardiomyocyte cross-sectional area, and fibrosis levels in rats. Apoptosis in myocardial tissue and in vitro was detected by TUNEL assay, while reactive oxygen species (ROS) content in tissues and cells was measured using DHE staining. Furthermore, the affinity of Prdx1 with Mat and PI3K was analyzed using computer-simulated molecular docking. Western blotting and RT-PCR were utilized to evaluate Prdx1 levels and proteins related to apoptosis and oxidative stress, as well as the mRNA levels of cardiac hypertrophy and fibrosis-related indicators.

RESULTS

Mat significantly alleviated cardiac hypertrophy and fibrosis induced by TAC, preserved cardiac function, and markedly reduced cardiomyocyte apoptosis and oxidative damage. In vitro, mat attenuated ang Ⅱ - induced hypertrophy of nrvms and activation of neonatal rat fibroblasts. Notably, activation of the PI3K/Akt/FoxO1 pathway and downregulation of Prdx1 expression were observed in TAC mice; however, these effects were reversed by Mat treatment. Furthermore, Prdx1 knockdown activated the PI3K/Akt/FoxO1 pathway, leading to exacerbation of the disease. Molecular docking indicated that Molecular docking indicated that Mat upregulated Prdx1 expression by binding to it, thereby inhibiting the PI3K/Akt/FoxO1 pathway and protecting the heart by restoring Prdx1 expression levels.

CONCLUSION

Matairesinol alleviates pressure overload-induced cardiac remodeling both in vivo and in vitro by upregulating Prdx1 expression and inhibiting the PI3K/Akt/FoxO1 pathway. This study highlights the therapeutic potential of Matairesinol in the treatment of cardiac hypertrophy and remodeling, providing a promising avenue for future research and clinical application.

Adipokines and their potential impacts on susceptibility to myocardial ischemia/reperfusion injury in diabetes

Coronary artery disease has a high mortality rate and is a striking public health concern, affecting a substantial portion of the global population. On the early onset of myocardial ischemia, thrombolytic therapy and coronary revascularization could promptly restore the bloodstream and nutrient supply to the ischemic tissue, efficiently preserving less severely injured myocardium. However, the abrupt re-establishment of blood flow triggers the significant discharge of previously accumulated oxidative substances and inflammatory cytokines, leading to further harm referred to as ischemia/reperfusion (I/R) injury. Diabetes significantly raises the vulnerability of the heart to I/R injury due to disrupted glucose and lipid processing, impaired insulin sensitivity and metabolic signaling, and increased inflammatory responses. Numerous studies have indicated that adipokines are crucial in the etiology and pathogenesis of obesity, diabetes, hyperlipidemia, hypertension, and coronary artery disease. Adipokines such as adiponectin, adipsin, visfatin, chemerin, omentin, and apelin, which possess protective properties against inflammatory activity and insulin resistance, have been shown to confer myocardial protection in conditions such as atherosclerosis, myocardial hypertrophy, myocardial I/R injury, and diabetic complications. On the other hand, adipokines such as leptin and resistin, known for their pro-inflammatory characteristics, have been linked to elevated cardiac lipid deposition, insulin resistance, and fibrosis. Meteorin-like (metrnl) exhibits opposite effects in various pathological conditions. However, the data on adipokines in myocardial I/R, especially in diabetes, is still incomplete and controversial. This review focuses on recent research regarding the categorization and function of adipokines in the heart muscle, and the identification of different signaling pathways involved in myocardial I/R injury under diabetic conditions, aiming to facilitate the exploration of therapeutic strategies against myocardial I/R injury in diabetes.

Metrnl as a secreted protein: Discovery and cardiovascular research

Secreted proteins have gained more and more attentions, since they can become therapeutic targets, drugs and biomarkers for prevention, diagnosis and treatment of disease and aging. In 2014, Metrnl (also named Meteorin-like, Cometin, Subfatin, Interleukin-39, Interleukin-41, Meteorin-β, and Metrn-β/Metrnβ), as a novel secreted protein released from a certain tissue, was reported by us and others. During the past decade, the number of articles on Metrnl has continued to increase. Different sources of Metrnl have been described with different functions, including Metrnl as an adipokine for insulin sensitization, a cardiokine against cardiac hypertrophy and dysfunction, an endothelium-derived factor against endothelial dysfunction and atherosclerosis, etc. Especially, we show that endothelial Metrnl is a major source for circulating Metrnl levels. Meanwhile, lots of clinical studies have investigated the relationship between blood Metrnl levels and metabolic, inflammatory and cardiovascular diseases. Metrnl appears a protective factor and a promising therapeutic target and/or drug against these diseases, given the relatively consistent conclusion from the preclinical studies. In addition to graphically demonstrating the role of Metrnl in various organs and diseases, this review will mainly describe the discovery of Metrnl, summarize the role of Metrnl in cardiovascular system that is a recently major progress in Metrnl research, and highlight several perspectives for future basic and translational research. Also, we suggest using one name Metrnl instead of other multiple names for the same protein.

NLRX1 and STING alleviate renal ischemia-reperfusion injury by regulating LC3 lipidation during mitophagy

Mitophagy significantly influences renal ischemia/reperfusion (I/R) injury and recovery. NLRX1 is recognized for its regulatory role in governing mitochondrial damage, autophagy, and the expression of pro-inflammatory factors. Despite the acknowledged involvement of NLRX1 in these crucial cellular processes, its specific function in renal I/R injury remains unclear. We detected the expression of NLRX1, the cGAS-STING pathway, and autophagy-related proteins using Western Blot analysis. RT-qPCR was utilized to measure the expression of NLRX1 mRNA and cytokines, and changes in mitochondrial DNA (mtDNA) within the cytoplasm. Immunofluorescence was applied to observe alterations in DNA distribution within the cytoplasm. The EtBr drug, which depletes mtDNA, and the Mdivi-1 mitophagy inhibitor, were used to verify the promotion of mitophagy by NLRX1. The results demonstrated that NLRX1 was downregulated after hypoxic/reoxygenation (H/R) injury, and there was an increase in cytoplasmic DNA. NLRX1 overexpression not only reduced IL-1β and IL-6 levels, but also decreased mtDNA in the cytoplasm. Additionally, NLRX1 further increases mitochondrial LC3 lipidation after H/R injury, and this effect is inhibited by Mdivi-1 drugs. The activation of the cGAS-STING pathway after H/R injury is inhibited by EtBr drugs and NLRX1. Co-immunoprecipitation results showed that NLRX1 could bind to STING. Moreover, inhibiting STING reversed NLRX1-induced mitochondrial LC3 lipidation. Our study reveals that NLRX1 can bind to STING to promote mitophagy and inhibits inflammation caused by mtDNA/cGAS/STING signaling.

Berberine prevents against myocardial injury induced by acute β-adrenergic overactivation in rats

The overactivation of β-adrenergic receptors (β-ARs) can result in acute myocardial ischemic injury, culminating in myocardial necrosis. Berberine (BBR) has exhibited promising potential for prevention and treatment in various heart diseases. However, its specific role in mitigating myocardial injury induced by acute β-AR overactivation remains unexplored. This study aimed to investigate the effects and underlying mechanisms of BBR pretreatment in a rat model of acute β-AR overactivation induced by a single dose of the nonselective β-adrenergic agonist isoprenaline (ISO). Rats were pretreated with saline or BBR (100 mg/kg/day) via gavage for 14 consecutive days, followed by a subcutaneous injection of ISO or saline on the 14th day. The findings indicated that BBR pretreatment significantly attenuated myocardial injury in ISO-stimulated rats, as evidenced by reduced pathological inflammatory infiltration, necrosis, and serum markers of myocardial damage. Additionally, BBR decreased oxidative stress and inflammation in the system and heart. Furthermore, BBR pretreatment enhanced myocardial ATP levels, improved mitochondrial dysfunction through increased Drp1 phosphorylation, and augmented myocardial autophagy. In a CoCl2-induced H9c2 cell hypoxic injury model, BBR pretreatment mitigated cellular injury, apoptosis, and oxidative stress while upregulating Drp1 and autophagy-associated proteins. Mechanistically, BBR pretreatment activated AKT, AMPK, and LKB1 both in vivo and in vitro, implicating the involvement of the AKT and LKB1/AMPK signaling pathways in its cardioprotective effects. Our study demonstrated the protective effects of BBR against myocardial injury induced by acute β-AR overactivation in rats, highlighting the potential of BBR as a preventive agent for myocardial injury associated with β-adrenergic overactivation.

The cGAS-STING/PERK-eIF2α: Individual or Potentially Collaborative Signaling Transduction in Cardiovascular Diseases

Over the past several decades, a canonical pathway called the cyclic GMP-AMP (cGAMP) synthase (cGAS)-stimulator of interferon genes (STING) mediating type I interferon (IFN) release via TANK-binding kinase 1(TBK1) / IFN regulatory factor 3 (IRF3) pathway has been widely investigated and characterized. Unexpectedly, recent studies show that the cGAS-STING noncanonically activates the protein kinase RNA-like ER kinase (PERK)-eukaryotic initiation factor 2α (eIF2α), an essential branch of unfolded protein response (UPR), even before the activation of the TBK1/IRF3 signaling. Additionally, we found that the PERK could regulate the STING signaling besides being modulated by upstream cGAS-STING. However, earlier evidence solely focused on the unidirectional regulation of STING and PERK, lacking their functional crosstalk. Hence, we postulate that there is a complex relationship between the cGAS-STING and PERK-eIF2α pathways and that, through convergent downstream signaling, they may collaboratively contribute to the pathophysiology of cardiovascular diseases (CVDs) via the cGAS-STING/PERK-eIF2α signaling axis. This study provides a novel pathway for the development of CVDs and paves the foundation for potential therapeutic targets for CVDs.

Role of cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes pathway in diabetes and its complications

Diabetes mellitus (DM) is one of the major causes of mortality worldwide, with inflammation being an important factor in its onset and development. This review summarizes the specific mechanisms of the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway in mediating inflammatory responses. Furthermore, it comprehensively presents related research progress and the subsequent involvement of this pathway in the pathogenesis of early-stage DM, diabetic gastroenteropathy, diabetic cardiomyopathy, non-alcoholic fatty liver disease, and other complications. Additionally, the role of cGAS-STING in autonomic dysfunction and intestinal dysregulation, which can lead to digestive complications, has been discussed. Altogether, this study provides a comprehensive analysis of the research advances regarding the cGAS-STING pathway-targeted therapeutic agents and the prospects for their application in the precision treatment of DM.

Regulation of autophagy by protein lipidation

Autophagy is a conserved catabolic recycling pathway that can eliminate cytosolic materials to maintain homeostasis and organelle functions. Many studies over the past few decades have demonstrated that abnormal autophagy is associated with a variety of diseases. Protein lipidation plays an important role in the regulation of autophagy by affecting protein trafficking, localization, stability, interactions and signal transduction. Here, we review recent advances in the understanding of the role of lipidation in autophagy, including S-palmitoylation, N-myristoylation, S-prenylation, glycosylphosphatidylinositol (GPI) anchor modification and cholesterylation. We comprehensively review the enzymes and catalytic mechanisms of lipidation and discuss the relationship between lipidation and autophagy, aiming to deepen the understanding of lipidation and promote the discovery of drug targets for the treatment of autophagy-related diseases.

Cyy-272, an indazole derivative, effectively mitigates obese cardiomyopathy as a JNK inhibitor

Obesity has shown a global epidemic trend. The high-lipid state caused by obesity can maintain the heart in a prolonged low-grade inflammatory state and cause ventricular remodeling, leading to a series of pathologies, such as hypertrophy, fibrosis, and apoptosis, which eventually develop into obese cardiomyopathy. Therefore, prolonged low-grade inflammation plays a crucial role in the progression of obese cardiomyopathy, making inflammation regulation an essential strategy for treating this disease. Cyy-272, an indazole derivative, is an anti-inflammatory compound independently synthesized by our laboratory. Our previous studies revealed that Cyy-272 can exert anti-inflammatory effects by inhibiting the phosphorylation and activation of C-Jun N-terminal kinase (JNK), thereby alleviating lipopolysaccharide (LPS)-induced acute lung injury (ALI). The current study aimed to evaluate the potential of Cyy-272 to mitigate the occurrence and progression of obese cardiomyopathy through the inhibition of the JNK signaling pathway. Our results indicate that the compound Cyy-272 has encouraging therapeutic effects on obesity-induced cardiac injury. It significantly inhibits inflammation in cardiomyocytes and heart tissues induced by high lipid concentrations, further alleviating the resulting hypertrophy, fibrosis, and apoptosis. Mechanistically, the protective effect of Cyy-272 on obese cardiomyopathy can be attributed to its direct inhibition of JNK protein phosphorylation. In conclusion, we identified a novel compound, Cyy-272, capable of alleviating obese cardiomyopathy and confirmed that its effect is achieved through direct inhibition of JNK.

Magnoflorine attenuates Ang II-induced cardiac remodeling via promoting AMPK-regulated autophagy

Background

Heart failure (HF) remains one of the most common events in the progression of hypertension. Magnoflorine (MNF) has been shown beneficial effects on the cardiovascular system. However, the action of MNF on angiotensin (Ang) II-induced cardiac remodeling and its underlying mechanisms have not yet been characterised. Here, we assessed the action of MNF in the development of hypertension-related HF.

Methods

C57BL/6 male mice were subjected to Ang II through a micro-osmotic pump infusion continuously for 4 weeks to induce hypertensive HF. MNF (10 and 20 mg/kg) was administered in the final 2 weeks. Ang II content was measured by enzyme-linked immunosorbent assay (ELISA) kit. Values of ejection fraction (EF) and fractional shortening (FS) were detected using an ultrasound diagnostic instrument. The mRNA levels of hypertrophic and fibrotic genes were determined by real-time quantitative polymerase chain reaction (RT-qPCR). Haematoxylin and eosin (H&E), wheat germ agglutinin (WGA), Masson trichrome, and Sirius Red staining were used to analyse pathologic changes in heart tissues. The expression levels of phosphorylated AMP-activated protein kinase (AMPK), light chain 3 microtubule associated protein II (LC3 II) to LC3 I, and p62 were detected by western blot assay.

Results

MNF significantly improved cardiac dysfunction and the content of creatine kinase-MB without altering blood pressure in Ang II-challenged mice. MNF obviously corrected the phenotypes of cardiac hypertrophy and fibrosis, including the high mRNA levels of atrial natriuretic peptide (Anp), brain natriuretic peptide (Bnp), collagen1a (Col1a1), transforming growth factor beta (Tgfb1), enlarged myocardial areas, and increased positive areas of Masson trichrome and Sirius Red staining. In addition, MNF alleviated oxidative injury, reflected by the upregulation of glutathione and the downregulation of reactive oxygen species and malondialdehyde. The activation of AMPK was elevated accompanied by an increased level of autophagy by MNF in hypertensive heart tissues. The therapeutic action of MNF was confirmed in Ang II-challenged H9c2 cells. Specifically, the AMPK inhibitor could eliminate the autophagy pathway in which MNF is involved.

Conclusions

MNF has benefits in hypertension-induced cardiac remodeling, which was partially associated with the improvement of oxidative stress via the mediation of the AMPK/autophagy axis.

Apigenin Attenuates Transverse Aortic Constriction-Induced Myocardial Hypertrophy: The Key Role of miR-185-5p/SREBP2-Mediated Autophagy

Introduction

Apigenin is a natural flavonoid compound with promising potential for the attenuation of myocardial hypertrophy (MH). The compound can also modulate the expression of miR-185-5p that both promote MH and suppress autophagy. The current attempts to explain the anti-MH effect of apigenin by focusing on changes in miR-185-5p-mediated autophagy.

Methods

Hypertrophic symptoms were induced in rats using transverse aortic constriction (TAC) method and in cardiomyocytes using Ang II and then handled with apigenin. Changes in myocardial function and structure and cell viability and surface area were measured. The role of miR-185-5p in the anti-MH function of apigenin was explored by detecting changes in autophagic processes and miR-185-5p/SREBP2 axis.

Results

TAC surgery induced weight increase, structure destruction, and collagen deposition in hearts of model rats. Ang II suppresses cardiomyocyte viability and increased cell surface area. All these impairments were attenuated by apigenin and were associated with the restored level of autophagy. At the molecular level, the expression of miR-185-5p was up-regulated by TAC, while the expression of SREBP2 was down-regulated, which was reserved by apigenin both in vivo and in vitro. The induction of miR-185-5p in cardiomyocytes could counteracted the protective effects of apigenin.

Discussion

Collectively, the findings outlined in the current study highlighted that apigenin showed anti-MH effects. The effects were related to the inhibition of miR-185-5p and activation of SREBP, which contributed to the increased autophagy.

Autophagy: Are Amino Acid Signals Dependent on the mTORC1 Pathway or Independent?

Autophagy is a kind of "self-eating" phenomenon that is ubiquitous in eukaryotic cells. It mainly manifests in the damaged proteins or organelles in the cell being wrapped and transported by the autophagosome to the lysosome for degradation. Many factors cause autophagy in cells, and the mechanism of nutrient-deficiency-induced autophagy has been a research focus. It has been reported that amino-acid-deficiency-induced cellular autophagy is mainly mediated through the mammalian rapamycin target protein complex 1 (mTORC1) signaling pathway. In addition, some researchers also found that non-mTORC1 signaling pathways also regulate autophagy, and the mechanism of autophagy occurrence induced by the deficiency of different amino acids is not precisely the same. Therefore, this review aims to summarize the process of various amino acids regulating cell autophagy and provide a narrative review on the molecular mechanism of amino acids regulating autophagy.

SIGMAR1 targets AMPK/ULK1 pathway to inhibit SH-SY5Y cell apoptosis by regulating endoplasmic reticulum stress and autophagy

Distal hereditary motor neuropathy (dHMN) is a progressive neurological disease characterized by distal limb muscle weakness and amyotrophy. Sigma 1 receptor (σ1R), a gene product of SIGMAR1, mutations have been reported to induce dHMN, but its mechanism remains unknown. This study aims to explore the effect of C238T and 31_50del mutations in σ1R on neuronal SH-SY5Y cell functions. The SH-SY5Y cells that overexpressed σ1R, C238T mutant σ1R (σ1RC238T) or 31_50del mutant σ1R (σ1R31_50del) were constructed by pEGFPN1 vectors. We used Western blot (WB) and immunofluorescence (IF) staining to detect the expression of σ1R and green fluorescent proteins (GFP). Then, we evaluated the impact of σ1R mutation on apoptosis, autophagy, endoplasmic reticulum stress, and the involvement of the unfolded protein response (UPR) pathway in SH-SY5Y cells. We found that σ1RC238T and σ1R31_50del downregulated σ1R and promoted the apoptosis of SH-SY5Y cells. σ1RC238T and σ1R31_50del increased p-PERK, p-eIF2α, p-JNK, BIP, ATF4, CHOP, ATF6, XBP1, Caspase3, Caspase12 expressions and Ca2+ concentration, whereas decreased ATP content in SH-SY5Y cells. Besides, the expressions of LC3B, Lamp1, ATG7, Beclin-1 and phosphorylation of AMPK and ULK1 were increased, while the p62 level decreased after C238T or 31_50del mutation of σ1R. Additionally, AMPK knockdown abolished the apoptosis mediated by σ1RC238T or σ1R31_50del in SH-SY5Y cells. Our results indicated that C238T or 31_50del mutation in σ1R promoted motor neuron apoptosis through the AMPK/ULK1 pathway in dHMN. This study shed light on a better understanding of the neurons pathological mechanisms mediated by σ1R C238T and σ1R 31-50del in dHMN.

Metrnl: a promising biomarker and therapeutic target for cardiovascular and metabolic diseases

Modern human society is burdened with the pandemic of cardiovascular and metabolic diseases. Metrnl is a widely distributed secreted protein in the body, involved in regulating glucose and lipid metabolism and maintaining cardiovascular system homeostasis. In this review, we present the predictive and therapeutic roles of Metrnl in various cardiovascular and metabolic diseases, including atherosclerosis, ischemic heart disease, cardiac remodeling, heart failure, hypertension, chemotherapy-induced myocardial injury, diabetes mellitus, and obesity.

Implications of endoplasmic reticulum stress and autophagy in aging and cardiovascular diseases

The average lifespan of humans has been increasing, resulting in a rapidly rising percentage of older individuals and high morbidity of aging-associated diseases, especially cardiovascular diseases (CVDs). Diverse intracellular and extracellular factors that interrupt homeostatic functions in the endoplasmic reticulum (ER) induce ER stress. Cells employ a dynamic signaling pathway of unfolded protein response (UPR) to buffer ER stress. Recent studies have demonstrated that ER stress triggers various cellular processes associated with aging and many aging-associated diseases, including CVDs. Autophagy is a conserved process involving lysosomal degradation and recycling of cytoplasmic components, proteins, organelles, and pathogens that invade the cytoplasm. Autophagy is vital for combating the adverse influence of aging on the heart. The present report summarizes recent studies on the mechanism of ER stress and autophagy and their overlap in aging and on CVD pathogenesis in the context of aging. It also discusses possible therapeutic interventions targeting ER stress and autophagy that might delay aging and prevent or treat CVDs.

Hydrangea paniculata coumarins alleviate adriamycin-induced renal lipotoxicity through activating AMPK and inhibiting C/EBPβ

ETHNOPHARMACOLOGICAL RELEVANCE

Throughout Chinese history, Hydrangea paniculata Siebold has been utilized as a traditional medicinal herb to treat a variety of ailments associated to inflammation. In a number of immune-mediated kidney disorders, total coumarins extracted from Hydrangea paniculata (HP) have demonstrated a renal protective effect.

AIM OF THE STUDY

To investigate renal beneficial effect of HP on experimental Adriamycin nephropathy (AN), and further clarify whether reversing lipid metabolism abnormalities by HP contributes to its renoprotective effect and find out the underlying critical pathways.

MATERIALS AND METHODS

After establishment of rat AN model, HP was orally administrated for 6 weeks. Biochemical indicators related to kidney injury were determined. mRNAs sequencing using kidney tissues were performed to clarify the underlying mechanism. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis, western blot, molecular docking, and drug affinity responsive target stability (DARTS) assay was carried out to further explore and confirm pivotal molecular pathways and possible target by which HP and 7-hydroxylcoumarin (7-HC) played their renal protection effect via modulating lipid metabolism.

RESULTS

HP could significantly improve renal function, and restore renal tubular abnormal lipid metabolism and interstitial fibrosis in AN. In vitro study demonstrated that HP and its main metabolite 7-HC could reduce ADR-induced intracellular lipid deposition and fibrosis characteristics in renal tubular cells. Mechanically, HP and 7-HC can activate AMP-activated protein kinase (AMPK) via direct interaction, which contributes to its lipid metabolism modulation effect. Moreover, HP and 7-HC can inhibit fibrosis by inhibiting CCAAT/enhancer binding protein beta (C/EBPβ) expression in renal tubular cells. Normalization of lipid metabolism by HP and 7-HC further provided protection of mitochondrial structure integrity and inhibited the nuclear factor kappa-B (NF-κB) pathway. Long-term toxicity using beagle dogs proved the safety of HP after one-month administration.

CONCLUSION

Coumarin derivates from HP alleviate adriamycin-induced lipotoxicity and fibrosis in kidney through activating AMPK and inhibiting C/EBPβ.

Role of AMPK-regulated autophagy in retinal pigment epithelial cell homeostasis: A review

The retinal pigment epithelium (RPE) is a regularly arranged monolayer of cells in the outermost layer of the retina. It is crucial for transporting nutrients and metabolic substances in the retina and maintaining the retinal barrier. RPE dysfunction causes diseases related to vision loss. Thus, understanding the mechanisms involved in normal RPE function is vital. Adenosine monophosphate-activated protein kinase (AMPK) is an RPE energy sensor regulating various signaling and metabolic pathways to maintain cellular energetic homeostasis. AMPK activation is involved in multiple signaling pathways regulated by autophagy in the RPE, thereby protecting the cells from oxidative stress and slowing RPE degeneration. In this review, we attempt to broaden the understanding of the pathogenesis of RPE dysfunction by focusing on the role and mechanism of AMPK regulation of autophagy in the RPE. The correlation between RPE cellular homeostasis and role of AMPK was determined by analyzing the structure and mechanism of AMPK and its signaling pathway in autophagy. The protective effect of AMPK-regulated autophagy on the RPE for gaining insights into the regulatory pathways of RPE dysfunction has been discussed.

Knockout of C1q/tumor necrosis factor-related protein-9 aggravates cardiac fibrosis in diabetic mice by regulating YAP-mediated autophagy

Introduction

Diabetic cardiomyopathy (DCM) is predominantly distinguished by impairment in ventricular function and myocardial fibrosis. Previous studies revealed the cardioprotective properties of C1q/tumor necrosis factor-related protein 9 (CTRP9). However, whether CTRP9 affects diabetic myocardial fibrosis and its underlying mechanisms remains unclear.

Methods

We developed a type 1 diabetes (T1DM) model in CTRP9-KO mice via streptozotocin (STZ) induction to examine cardiac function, histopathology, fibrosis extent, Yes-associated protein (YAP) expression, and the expression of markers for autophagy such LC3-II and p62. Additionally, we analyzed the direct impact of CTRP9 on high glucose (HG)-induced transdifferentiation, autophagic activity, and YAP protein levels in cardiac fibroblasts.

Results

In diabetic mice, CTRP9 expression was decreased in the heart. The absence of CTRP9 aggravated cardiac dysfunction and fibrosis in mice with diabetes, alongside increased YAP expression and impaired autophagy. In vitro, HG induced the activation of myocardial fibroblasts, which demonstrated elevated cell proliferation, collagen production, and α-smooth muscle actin (α-SMA) expression. CTRP9 countered these adverse effects by restoring autophagy and reducing YAP protein levels in cardiac fibroblasts. Notably, the protective effects of CTRP9 were negated by the inhibition of autophagy with chloroquine (CQ) or by YAP overexpression through plasmid intervention. Notably, the protective effect of CTRP9 was negated by inhibition of autophagy caused by chloroquine (CQ) or plasmid intervention with YAP overexpression.

Discussion

Our findings suggest that CTRP9 can enhance cardiac function and mitigate cardiac remodeling in DCM through the regulation of YAP-mediated autophagy. CTRP9 holds promise as a potential candidate for pharmacotherapy in managing diabetic cardiac fibrosis.

The study of the mechanism of non-coding RNA regulation of programmed cell death in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) represents a distinct myocardial disorder elicited by diabetes mellitus, characterized by aberrations in myocardial function and structural integrity. This pathological condition predominantly manifests in individuals with diabetes who do not have concurrent coronary artery disease or hypertension. An escalating body of scientific evidence substantiates the pivotal role of programmed cell death (PCD)-encompassing apoptosis, autophagy, pyroptosis, ferroptosis, and necroptosis-in the pathogenic progression of DCM, thereby emerging as a prospective therapeutic target. Additionally, numerous non-coding RNAs (ncRNAs) have been empirically verified to modulate the biological processes underlying programmed cell death, consequently influencing the evolution of DCM. This review systematically encapsulates prevalent types of PCD manifest in DCM as well as nascent discoveries regarding the regulatory influence of ncRNAs on programmed cell death in the pathogenesis of DCM, with the aim of furnishing novel insights for the furtherance of research in PCD-associated disorders relevant to DCM.