Fucoxanthin ameliorated myocardial fibrosis in STZ-induced diabetic rats and cell hypertrophy in HG-induced H9c2 cells by alleviating oxidative stress and restoring mitophagy

α-Mangostin prevents diabetic cardiomyopathy by inhibiting oxidative damage and lipotoxicity through the AKT-FOXO1-CD36 pathway

Introduction

Diabetic cardiomyopathy (DCM), a cardiac complication of diabetes, is the main cause of the high prevalence of heart failure and associated mortality in diabetic patients. Oxidative stress and lipid metabolism disorder-induced myocardial cell damage are part of the pathogenesis of DCM. In this study, we investigated the effects of alpha-mangostin (A-MG), a natural antioxidant extracted from mangosteen peel, on in vitro and in vivo DCM models.

Methods

H9C2 rat cardiomyocytes were treated with high glucose (HG) and palmitic acid (PA) for 24 h to establish an in vitro DCM cell model. Cell viability and cytotoxicity were evaluated after treatment with varying concentrations of A-MG (0.3, 1, 3, 9, or 27 μM) using Cell Counting Kit-8 (CCK8) and lactate dehydrogenase (LDH) assays. Flow cytometry assessment was used to detect apoptosis. Molecular mechanisms were investigated through transcriptome analysis, quantitative PCR (RT-qPCR), and Western blotting. Type 2 diabetic (T2D) mice, induced by feeding a high-fat diet (HFD) combined with low-dose streptozotocin (STZ), received either vehicle, low-dose A-MG (100 mg/kg/d), or high-dose A-MG (200 mg/kg/d) for 6 weeks. Cardiac function was assessed by echocardiography. H&E and Masson's staining were used to evaluate cardiac tissue structure and fibrosis, and Western blotting was used to evaluate myocardial protein expression.

Results

In HG/F-induced H9C2 cells, A-MG (1 and 3 μM) significantly increased cell viability (p < 0.01) and reduced LDH release (p < 0.05). A-MG (3 μM) attenuated lipid accumulation (p < 0.05), normalized mitochondrial membrane potential (p < 0.01), and inhibited reactive oxygen species (ROS) generation (p < 0.05), malondialdehyde (MDA) production (p < 0.01), and apoptosis (p < 0.05). A-MG also inhibited the nuclear translocation of Forkhead box class O1 (FOXO1) (p < 0.05); reduced the expression of CD36 (p < 0.05), PPARα (p < 0.01), and CPT1β (p < 0.05) proteins; enhanced superoxide dismutase (SOD) activity (p < 0.05); and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) (p < 0.01), HO-1 (p < 0.05), and SOD2 (p < 0.05) protein expression levels. Further investigation in HG/F-induced H9C2 cells indicated that A-MG inhibits the uptake of fatty acids (FAs) by regulating the AKT/FOXO1/CD36 signaling pathway, reduces excessive β-oxidation of FAs mediated by PPARα/CPT1β through the inhibition of FOXO1 nuclear translocation, and stimulates the AKT/Nrf2/HO-1 signaling pathway to increase the cellular antioxidant capacity. In diabetic mice, low-dose A-MG treatment increased anti-oxidative stress capacity, decreased myocardial lipid accumulation, reduced fibrosis and cardiomyocyte apoptosis, and improved left ventricular contractile function.

Conclusion

Using both in vitro and in vivo DCM models, our study demonstrates that A-MG reduces lipid accumulation and excessive mitochondrial β-oxidation while enhancing antioxidant capacity. These results suggest that A-MG may be a novel therapeutic option for DCM.

Natural small molecules regulating the mitophagy pathway counteract the pathogenesis of diabetes and chronic complications

Diabetes mellitus (DM) is a chronic metabolic disorder marked by sustained hyperglycemia. These disturbances contribute to extensive damage across various tissues and organs, giving rise to severe complications such as vision loss, kidney failure, amputations, and higher morbidity and mortality rates. Furthermore, DM imposes a substantial economic and emotional burden on patients, families, and healthcare systems. Mitophagy, a selective process that targets the clearance of damaged or dysfunctional mitochondria, is pivotal for sustaining cellular homeostasis through mitochondrial turnover and recycling. Emerging evidence indicates that dysfunctional mitophagy acts as a key pathogenic driver in the pathogenesis of DM and its associated complications. Natural small molecules are particularly attractive in this regard, offering advantages such as low toxicity, favorable pharmacokinetic profiles, excellent biocompatibility, and a broad range of biochemical activities. This review systematically evaluates the mechanistic roles of natural small molecules-including ginsenosides, resveratrol, and berberine-in enhancing mitophagy and restoring mitochondrial homeostasis via activation of core signaling pathways (e.g., PINK1/Parkin, BNIP3/NIX, and FUNDC1). These pathways collectively ameliorate pathological hallmarks of DM, such as oxidative stress, chronic inflammation, and insulin resistance. Furthermore, the integration of nanotechnology with these compounds optimizes their bioavailability and tissue-specific targeting, thereby establishing a transformative therapeutic platform for DM management. Current evidence demonstrates that mitophagy modulation by natural small molecules not only offers novel therapeutic strategies for DM and its chronic complications but also advances the mechanistic foundation for future drug development targeting metabolic disorders.

A comprehensive review on diabetic cardiomyopathy (DCM): histological spectrum, diagnosis, pathogenesis, and management with conventional treatments and natural compounds

Diabetic complications are among the most pressing health issues currently. Cardiovascular problems, particularly diabetic cardiomyopathy (DCM), are responsible for almost 80% of diabetic deaths. Because of the increasing prevalence of diabetes and the increased threat of death from its consequences, researchers are searching for new pharmaceutical targets to delay or cure it. Currently, there are a few medicines available for the treatment of DCM, some of which have serious side effects. To address this issue, researchers are focusing on natural products. Thus, in this review, we discuss the prevalence, incidence, risk factors, histological spectrum, diagnosis, pathogenic pathways of DCM, genetic and epigenetic mechanisms involved in DCM, the current treatments, and the beneficial effects of natural product-based therapeutics. Natural treatments range from single doses to continuous regimens lasting weeks or months. Flavonoids are the largest class of natural compounds reported for the treatment of DCM. Natural regimens may cover the way for new treatment strategies for DCM for being multi-target agents in the treatment of DCM, with the ability to play a variety of functions via distinct signaling pathways.

Important regulatory role of mitophagy in diabetic microvascular complications

Microvascular complications of diabetes pose a significant threat to global health, mainly including diabetic kidney disease (DKD), diabetic retinopathy (DR), diabetic peripheral neuropathy (DPN), and diabetic cardiomyopathy (DCM), which can ultimately lead to kidney failure, blindness, disability, and heart failure. With the increasing prevalence of diabetes, the search for new therapeutic targets for diabetic microvascular complications is imminent. Mitophagy is a widespread and strictly maintained process of self-renewal and energy metabolism that plays an important role in reducing inflammatory responses, inhibiting reactive oxygen species accumulation, and maintaining cellular energy metabolism. Hyperglycemia results in impaired mitophagy, which leads to mitochondrial dysfunction and ultimately exacerbates disease progression. This article summarizes the relevant molecular mechanisms of mitophagy and reviews the current status of research on regulating mitophagy as a potential treatment for diabetic microvascular complications, attempting to give new angles on the treatment of diabetic microvascular complications.

The measurement of microplastics in surface water and their impact on histopathological structures in wading birds of district Lahore

Plastics are globally considered a significant threat, particularly to metropolitan areas, due to the extensive use of plastic products. This research is the first of its kind to document microplastics contamination and its effects on Red wettled lapwing (Vanellus indicus). The concentration of microplastics (MPs) was measured from surface water at different locations including canals and drains, which are the primary sources of MPs pollution in the metropolitan city Lahore, Pakistan. The highest MPs concentration was recorded in the main stream of the Ravi River, with an average concentration of 5,150 ± 7.5 particles/m3. In addition, considering the different shapes of MPs, fibers were found to be most abundant at Site I (Main Stream of River Ravi), with the highest mean concentration of 92.4 ± 0.3 particles/m3, whereas the lowest mean concentration of 29.9 ± 0.1 particles/m3 was observed. In contrast, fragments were predominant at Site II (Shahdara Drain), with the highest and lowest mean concentrations of 42.6 ± 0.3 and 21.7 ± 0.1particles/m3, respectively. Chemical analysis revealed that most fragments, fibers; and beads belonged to the polyethylene class, while sheets were categorized as polypropylene and foam as polystyrene. The large MPs with particle size ranging from 400 μm to 5 mm were most abundant at both locations. Particles smaller than 0.5 mm were the most prevalent (56%) at Site I, while Site II showed the lowest proportions for size ranges 0.5-1 mm (24%), 1-2 mm (16%), 2-3 mm (8%), 3-4 mm (5%), and 4-5 mm (3%). The frequency of occurrence (%FO; prevalence) of plastics in necropsied birds was 89.7%. A total of 120 items were analyzed: 64 fibers, 23 fragments, 10 pieces of foam, 14 pieces of sheet, and 9 beads. Of the total ingested plastic debris analyzed, the largest proportion was comprised of polyethylene, making up 46% of the samples. Birds from Site I (Main Stream of River Ravi) had 100% of their organs containing plastic items compared to those from Site II (Shahdara Drain). Quantitative and qualitative histopathological analyses were performed to examine variations in prevalence percentage, frequency, and histological alteration indices (HAI) as a consequence of MPs exposure on the health of wild species. Tissue samples from the liver and kidneys of the Red-wattled lapwing were analyzed, and comparisons were made to assess the extent of damage and degree of alteration in bird organs. The study evaluated the impacts of ingested MPs, which induced inflammatory and anatomical responses in V. indicus. Significant tissue damage was observed, including considerable inflammatory responses, evident cellular swelling in many renal tubular epithelial cells, and pyknotic nuclei, which were major causes of necrosis and apoptosis. Prevalence percentage and frequency were significantly higher at Site I compared to Site II. The highest prevalence percentages in the liver and kidneys were 90% and 85%, respectively, manifesting as degeneration of hepatocytes and necrosis in renal tubular epithelial cells in response to 0.5-1 mm sized MPs. The lowest prevalence percentage, 5%, was observed as congestion of sinusoids and hyperemia in response to 4-5 mm sized MPs. The frequency and prevalence percentages followed the order: 0.5 mm > 0.5-1 mm > 1-2 mm > 2-3 mm > 3-4 mm > 4-5 mm > 0 mm (0 mm as control).This investigation contributes to the growing documentation of MPs abundance in freshwater ecosystems and provides a baseline for future studies on MPs pollution in the Ravi River.

TAK-242 alleviates diabetic cardiomyopathy via inhibiting pyroptosis and TLR4/CaMKII/NLRP3 pathway

Diabetic cardiomyopathy (DCM) is identified as a progressive disease that may lead to irreparable heart failure. Toll-like receptor (TLR) signaling is believed to be implicated in the pathogenesis of DCM. This study intended to explore the potential impact of Toll-like receptor 4 (TLR4) on DCM in vitro and in vivo. Streptozotocin and HG medium were utilized to induce diabetes in animal and cell models, respectively. Selective TLR4 inhibitor TAK-242 and calcium/calmodulin-dependent protein kinase-II (CaMKII) inhibitor KN-93 were employed to explore the involvement of TLR4/CaMKII in DCM. TLR4 expression was increased in DCM hearts, while inhibition of TLR4 activation by TAK-242 improved cardiac function, attenuated heart hypertrophy, and fibrosis, as well as reduced oxidative stress and proinflammatory cytokine levels in rats, which were confirmed by Doppler echocardiography, hematoxylin and eosin staining, and Masson Trichome staining and specific enzyme-linked immunosorbent assay kits. Besides, the expression of hypertrophy-related molecules and oxidative stress damage were also inhibited by TAK-242. Furthermore, TAK-242 treatment reduced CaMKII phosphorylation accompanied by decreased expression of NOD-like pyrin domain-containing protein 3, gasdermin D (GSDMD), The N-terminal domain of Gasdermin D (GSDMD-N), apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) and Caspase-1 both in vivo and in vitro. Similar positive impacts on HG-induced pyroptosis were also observed with KN-93 treatment, and this was achieved without affecting TLR4 expression. Collectively, our work suggested that TAK-242 demonstrated substantial benefits against DCM both in vivo and in vitro, potentially attributed to the suppression of the TLR4-mediated CaMKII/NLRP3 pathway activity.

Mitophagy in fibrotic diseases: molecular mechanisms and therapeutic applications

Mitophagy is a highly precise process of selective autophagy, primarily aimed at eliminating excess or damaged mitochondria to maintain the stability of both mitochondrial and cellular homeostasis. In recent years, with in-depth research into the association between mitophagy and fibrotic diseases, it has been discovered that this process may interact with crucial cellular biological processes such as oxidative stress, inflammatory responses, cellular dynamics regulation, and energy metabolism, thereby influencing the occurrence and progression of fibrotic diseases. Consequently, modulating mitophagy holds promise as a therapeutic approach for fibrosis. Currently, various methods have been identified to regulate mitophagy to prevent fibrosis, categorized into three types: natural drug therapy, biological therapy, and physical therapy. This review comprehensively summarizes the current understanding of the mechanisms of mitophagy, delves into its biological roles in fibrotic diseases, and introduces mitophagy modulators effective in fibrosis, aiming to provide new targets and theoretical basis for the investigation of fibrosis-related mechanisms and disease prevention.

Integrative transcriptomics and proteomics analysis reveal the protection of Astragaloside IV against myocardial fibrosis by regulating senescence

Myocardial fibrosis (MF) is a pivotal pathological process implicated in various cardiovascular diseases, particularly heart failure. Astragaloside IV (AS-IV), a natural compound derived from Astragalus membranaceus, possesses potent cardioprotective properties. However, the precise molecular mechanisms underlying its anti-MF effects, particularly in relation to senescence, remain elusive. Thus, this study aimed to investigate the therapeutic potential and underlying molecular mechanisms of AS-IV in treating ISO-induced MF in mice, employing transcriptomics, proteomics, in vitro, and in vivo experiments. We assessed the positive effects of AS-IV on ISO-induced MF using HE staining, Masson staining, ELISA, immunohistochemical staining, transthoracic echocardiography, transmission electron microscopy, and DHE fluorescence staining. Additionally, we elucidated the regulatory role of AS-IV in MF through comprehensive transcriptomics and proteomics analyses, complemented by Western blotting and RT-qPCR validation of pertinent molecular pathways. Our findings demonstrated that AS-IV treatment markedly attenuated ISO-induced myocardial injury and oxidative stress, concomitantly inhibiting the release of SASPs. Furthermore, integrated transcriptomics and proteomics analyses revealed that the anti-MF mechanism of AS-IV was associated with regulating cellular senescence and the p53 signaling pathway. These results highlight AS-IV exerts its anti-MF effects not only by inhibiting oxidative stress but also by modulating senescence through the p53 signaling pathway.

Fucoxanthin alleviates lipopolysaccharide-induced intestinal barrier injury in mice

The aim of this study was to evaluate the preventive role and underlying mechanisms of fucoxanthin (Fx) on lipopolysaccharide (LPS)-induced intestinal barrier injury in mice. Our results demonstrated that the oral administration of Fx (50 and 200 mg per kg body weight per day) for consecutive 7 days significantly alleviated the severity of LPS-induced intestinal barrier injury in mice, as evidenced by attenuating body weight loss, improving intestinal permeability, and ameliorating intestinal morphological damage such as reduction in the ratio of the villus length to the crypt depth (V/C), intestinal epithelium distortion, goblet cell depletion, and low mucin 2 (MUC2) expression. Fx also significantly mitigated LPS-induced excessive apoptosis of intestinal epithelial cells (IECs) and curbed the decrease of tight junction proteins including claudin-1, occludin, and zonula occludens-1 in the ileum and colon. Additionally, Fx effectively alleviated LPS-induced extensive infiltration of macrophages and neutrophils into the intestinal mucosa, the overproduction of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin 1beta (IL-1β) and IL-6, and gasdermin D (GSDMD)-mediated pyroptosis of IECs. The underlying mechanisms might be associated with inhibiting the activation of nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs) and nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome signaling pathways. Moreover, Fx also notably restrained intestinal reactive oxygen species (ROS), malondialdehyde and protein carbonylation levels in LPS-treated mice, and it might be mediated by activating the nuclear factor-erythroid 2 related factor 2 (Nrf2) signaling pathway. Overall, these findings indicated that Fx might be developed as a potential effective dietary supplement to prevent intestinal barrier injury.

Targeting autophagy in diabetic cardiomyopathy: From molecular mechanisms to pharmacotherapy

Diabetic cardiomyopathy (DCM) is a cardiac microvascular complication caused by metabolic disorders. It is characterized by myocardial remodeling and dysfunction. The pathogenesis of DCM is associated with abnormal cellular metabolism and organelle accumulation. Autophagy is thought to play a key role in the diabetic heart, and a growing body of research suggests that modulating autophagy may be a potential therapeutic strategy for DCM. Here, we have summarized the major signaling pathways involved in the regulation of autophagy in DCM, including Adenosine 5'-monophosphate-activated protein kinase (AMPK), mechanistic target of rapamycin (mTOR), Forkhead box subfamily O proteins (FOXOs), Sirtuins (SIRTs), and PTEN-inducible kinase 1 (PINK1)/Parkin. Given the significant role of autophagy in DCM, we further identified natural products and chemical drugs as regulators of autophagy in the treatment of DCM. This review may help to better understand the autophagy mechanism of drugs for DCM and promote their clinical application.

Traditional Chinese medicine and mitophagy: A novel approach for cardiovascular disease management

BACKGROUND

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, imposing an enormous economic burden on individuals and human society. Laboratory studies have identified several drugs that target mitophagy for the prevention and treatment of CVD. Only a few of these drugs have been successful in clinical trials, and most studies have been limited to animal and cellular models. Furthermore, conventional drugs used to treat CVD, such as antiplatelet agents, statins, and diuretics, often result in adverse effects on patients' cardiovascular, metabolic, and respiratory systems. In contrast, traditional Chinese medicine (TCM) has gained significant attention for its unique theoretical basis and clinical efficacy in treating CVD.

PURPOSE

This paper systematically summarizes all the herbal compounds, extracts, and active monomers used to target mitophagy for the treatment of CVD in the last five years. It provides valuable information for researchers in the field of basic cardiovascular research, pharmacologists, and clinicians developing herbal medicines with fewer side effects, as well as a useful reference for future mitophagy research.

METHODS

The search terms "cardiovascular disease," "mitophagy," "herbal preparations," "active monomers," and "cardiac disease pathogenesis" in combination with "natural products" and "diseases" were used to search for studies published in the past five years until January 2024.

RESULTS

Studies have shown that mitophagy plays a significant role in the progression and development of CVD, such as atherosclerosis (AS), heart failure (HF), myocardial infarction (MI), myocardial ischemia/reperfusion injury (MI/RI), cardiac hypertrophy, cardiomyopathy, and arrhythmia. Herbal compound preparations, crude extracts, and active monomers have shown potential as effective treatments for these conditions. These substances protect cardiomyocytes by inducing mitophagy, scavenging damaged mitochondria, and maintaining mitochondrial homeostasis. They display notable efficacy in combating CVD.

CONCLUSION

TCM (including herbal compound preparations, extracts, and active monomers) can treat CVD through various pharmacological mechanisms and signaling pathways by inducing mitophagy. They represent a hotspot for future cardiovascular basic research and a promising candidate for the development of future cardiovascular drugs with fewer side effects and better therapeutic efficacy.

Molecular Mechanisms of Fucoxanthin in Alleviating Lipid Deposition in Metabolic Associated Fatty Liver Disease

Metabolic-associated fatty liver disease (MAFLD) is witnessing a global surge; however, it still lacks effective pharmacological interventions. Fucoxanthin, a natural bioactive metabolite derived from marine brown algae, exhibits promising pharmacological functions, particularly in ameliorating metabolic disorders. However, the mechanisms underlying its therapeutic efficacy in addressing MAFLD remain elusive. Our present findings indicated that fucoxanthin significantly alleviated palmitic acid (PA)-induced hepatic lipid deposition in vitro and obesity-induced hepatic steatosis in ob/ob mice. Moreover, at both the protein and transcriptional levels, fucoxanthin effectively increased the expression of PPARα and CPT1 (involved in fatty acid oxidation) and suppressed FASN and SREBP1c (associated with lipogenesis) in both PA-induced HepG2 cells and hepatic tissues in ob/ob mice. This modulation was accompanied by the activation of AMPK. The capacity of fucoxanthin to improve hepatic lipid deposition was significantly attenuated when utilizing the AMPK inhibitor or siRNA-mediated AMPK silencing. Mechanistically, fucoxanthin activates AMPK, subsequently regulating the KEAP1/Nrf2/ARE signaling pathway to exert antioxidative effects and stimulating the PGC1α/NRF1 axis to enhance mitochondrial biogenesis. These collective actions contribute to fucoxanthin's amelioration of hepatic steatosis induced by metabolic perturbations. These findings offer valuable insights into the prospective utilization of fucoxanthin as a therapeutic strategy for managing MAFLD.

Human umbilical cord-derived mesenchymal stromal cells improve myocardial fibrosis and restore miRNA-133a expression in diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is a serious health-threatening complication of diabetes mellitus characterized by myocardial fibrosis and abnormal cardiac function. Human umbilical cord mesenchymal stromal cells (hUC-MSCs) are a potential therapeutic tool for DCM and myocardial fibrosis via mechanisms such as the regulation of microRNA (miRNA) expression and inflammation. It remains unclear, however, whether hUC-MSC therapy has beneficial effects on cardiac function following different durations of diabetes and which mechanistic aspects of DCM are modulated by hUC-MSC administration at different stages of its development. This study aimed to investigate the therapeutic effects of intravenous administration of hUC-MSCs on DCM following different durations of hyperglycemia in an experimental male model of diabetes and to determine the effects on expression of candidate miRNAs, target mRNA and inflammatory mediators.

METHODS

A male mouse model of diabetes was induced by multiple low-dose streptozotocin injections. The effects on severity of DCM of intravenous injections of hUC-MSCs and saline two weeks previously were compared at 10 and 18 weeks after diabetes induction. At both time-points, biochemical assays, echocardiography, histopathology, polymerase chain reaction (PCR), immunohistochemistry and enzyme-linked immunosorbent assays (ELISA) were used to analyze blood glucose, body weight, cardiac structure and function, degree of myocardial fibrosis and expression of fibrosis-related mRNA, miRNA and inflammatory mediators.

RESULTS

Saline-treated diabetic male mice had impaired cardiac function and increased cardiac fibrosis after 10 and 18 weeks of diabetes. At both time-points, cardiac dysfunction and fibrosis were improved in hUC-MSC-treated mice. Pro-fibrotic indicators (α-SMA, collagen I, collagen III, Smad3, Smad4) were reduced and anti-fibrotic mediators (FGF-1, miRNA-133a) were increased in hearts of diabetic animals receiving hUC-MSCs compared to saline. Increased blood levels of pro-inflammatory cytokines (IL-6, TNF, IL-1β) and increased cardiac expression of IL-6 were also observed in saline-treated mice and were reduced by hUC-MSCs at both time-points, but to a lesser degree at 18 weeks.

CONCLUSION

Intravenous injection of hUC-MSCs ameliorated key functional and structural features of DCM in male mice with diabetes of shorter and longer duration. Mechanistically, these effects were associated with restoration of intra-myocardial expression of miRNA-133a and its target mRNA COL1AI as well as suppression of systemic and localized inflammatory mediators.

Targeting autophagy with natural products as a potential therapeutic approach for diabetic microangiopathy

As the quality of life improves, the incidence of diabetes mellitus and its microvascular complications (DMC) continues to increase, posing a threat to people's health and wellbeing. Given the limitations of existing treatment, there is an urgent need for novel approaches to prevent and treat DMC. Autophagy, a pivotal mechanism governing metabolic regulation in organisms, facilitates the removal of dysfunctional proteins and organelles, thereby sustaining cellular homeostasis and energy generation. Anomalous states in pancreatic β-cells, podocytes, Müller cells, cardiomyocytes, and Schwann cells in DMC are closely linked to autophagic dysregulation. Natural products have the property of being multi-targeted and can affect autophagy and hence DMC progression in terms of nutrient perception, oxidative stress, endoplasmic reticulum stress, inflammation, and apoptosis. This review consolidates recent advancements in understanding DMC pathogenesis via autophagy and proposes novel perspectives on treating DMC by either stimulating or inhibiting autophagy using natural products.

PDE12 disrupts mitochondrial oxidative phosphorylation and mediates mitochondrial dysfunction to induce oral mucosal epithelial barrier damage in oral submucous fibrosis

Oral submucous fibrosis (OSF) is a chronic oral mucosal disease. The pathological changes of OSF include epithelial damage and subepithelial matrix fibrosis. This study aimed to reveal the epithelial injury mechanism of OSF. A histopathological method was used to analyze oral mucosal tissue from OSF patients and OSF rats. The expression of PDE12 in the oral epithelium was analyzed by immunohistochemistry. The epithelial-mesenchymal transition (EMT) and tight junction proteins in arecoline-treated HOKs were explored by western blotting. Epithelial leakage was assessed by transepithelial electrical resistance and lucifer yellow permeability. The expression of PDE12 and the mitochondrial morphology, mitochondrial permeability transition pore opening, mitochondrial membrane potential, and mitochondrial reactive oxygen species (mtROS) were evaluated in arecoline-induced HOKs. Oxidative phosphorylation (OXPHOS) complexes and ATP content were also explored in HOKs. The results showed significant overexpression of PDE12 in oral mucosal tissue from OSF patients and rats. PDE12 was also overexpressed and aggregated in mitochondria in arecoline-induced HOKs, resulting in dysfunction of OXPHOS and impaired mitochondrial function. An EMT, disruption of tight junctions with epithelial leakage, and extracellular matrix remodeling were also observed. PDE12 overexpression induced by PDE12 plasmid transfection enhanced the mtROS level and interfered with occludin protein localization in HOKs. Interestingly, knockdown of PDE12 clearly ameliorated arecoline-induced mitochondrial dysfunction and epithelial barrier dysfunction in HOKs. Therefore, we concluded that overexpression of PDE12 impaired mitochondrial OXPHOS and mitochondrial function and subsequently impaired epithelial barrier function, ultimately leading to OSF. We suggest that PDE12 may be a new potential target against OSF.

(-)-Epicatechin and colonic metabolite 2,3-dihydroxybenzoic acid, alone or in combination with metformin, protect cardiomyocytes from high glucose/high palmitic acid-induced damage by regulating redox status, apoptosis and autophagy

(-)-Epicatechin (EC) and a main colonic phenolic acid derived from flavonoid intake, 2,3-dihydroxybenzoic acid (DHBA), display antioxidant and antidiabetic activities. Diabetic cardiomyopathy (DCM) is one of the main causes of mortality in patients with diabetes, lacking a suitable treatment. Hyperglycaemia and dyslipidaemia are mainly responsible for oxidative stress and altered apoptosis and autophagy in cardiomyocytes during DCM. In this context, phenolic compounds could be suitable candidates for alleviating DCM, but have scarcely been investigated or their use in combination with antidiabetic drugs. This study evaluates the effects of EC, DHBA and antidiabetic drug metformin (MET), alone or all combined (MIX), on redox status, autophagy and apoptosis in H9c2 cardiomyocytes challenged with high concentrations of glucose (HG) and palmitic acid (PA). Under HG + PA conditions, EC, DHBA, MET and MIX equally improved redox status, reduced apoptosis induction and ameliorated autophagy inhibition. Mechanistically, all treatments alleviated HG + PA-induced oxidative stress by reinforcing antioxidant defences (∼40% increase in glutathione, ∼30% diminution in GPx activity and ∼15% increase in SOD activity) and reducing ROS generation (∼20%), protein oxidation (∼35%) and JNK phosphorylation (∼200%). Additionally, all treatments mitigated HG + PA-induced apoptosis and activated autophagy by decreasing Bax (∼15-25%), caspase-3 (∼20-40%) and p62 (∼20-40%), and increasing Bcl-2, beclin-1 and LC3-II/LC3-I (∼40-60%, ∼15-20%, and ∼25-30%, respectively). JNK inhibition improved protective changes to redox status, apoptosis and autophagy that were observed in EC-, DHBA- and MIX-mediated protection. Despite no additive or synergistic effects being detected when phenolic compounds and MET were combined, these results provide the first evidence for the benefits of EC and DHBA, comparable to those of MET alone, to ameliorate cardiomyocyte damage, that involve an improvement in antioxidant competence, autophagy and apoptosis, these effects being mediated at least by targeting JNK.

Fucoxanthin alleviated myocardial ischemia and reperfusion injury through inhibition of ferroptosis via the NRF2 signaling pathway

Background: Myocardial ischemia and reperfusion injury (MIRI) is a severe complication of revascularization therapy in patients with myocardial infarction. Therefore, there is an urgent requirement to find more therapeutic solutions for MIRI. Recently, ferroptosis, which is characterized by lipid peroxidation, was considered a critical contributor to MIRI. Fucoxanthin (FX), a natural antioxidant carotenoid, which is abundant in brown seaweed, exerts protective effects under various pathological conditions. However, whether FX alleviates MIRI is unclear. This study aims to clarify the effects of FX on MIRI. Methods: Mice with left anterior descending artery ligation and reperfusion were used as in vivo models. Neonatal rat cardiomyocytes (NRCs) induced with hypoxia and reperfusion were used as in vitro models. TTC-Evans blue staining was performed to validate the infarction size. Transmission electron microscopy was employed to detect mitochondrial injury in cardiomyocytes. In addition, 4 weeks after MIRI, echocardiography was performed to measure cardiac function; fluorescent probes and western blots were used to detect ferroptosis. Results: TTC-Evans blue staining showed that FX reduced the infarction size induced by MIRI. Transmission electron microscopy showed that FX ameliorated the MIRI-induced myofibril loss and mitochondrion shrinkage. Furthermore, FX improved LVEF and LVFS and inhibited myocardial hypertrophy and fibrosis after 4 weeks in mice with MIRI. In the in vitro study, calcein AM/PI staining and TUNEL staining showed that FX reduced cell death caused by hypoxia and reperfusion treatment. DCFH-DA and MitoSOX probes indicated that FX inhibited cellular and mitochondrial reactive oxygen species (ROS). Moreover, C11-BODIPY 581/591 staining, ferro-orange staining, MDA assay, Fe2+ assay, 4-hydroxynonenal enzyme-linked immunosorbent assay, and western blot were performed and the results revealed that FX ameliorated ferroptosis in vitro and in vivo, as indicated by inhibiting lipid ROS and Fe2+ release, as well as by modulating ferroptosis hallmark FTH, TFRC, and GPX4 expression. Additionally, the protective effects of FX were eliminated by the NRF2 inhibitor brusatol, as observed from western blotting, C11-BODIPY 581/591 staining, and calcein AM/PI staining, indicating that FX exerted cardio-protective effects on MIRI through the NRF2 pathway. Conclusion: Our study showed that FX alleviated MIRI through the inhibition of ferroptosis via the NRF2 signaling pathway.

Fucoxanthin inhibits cardiac fibroblast transdifferentiation by alleviating oxidative stress through downregulation of BRD4

Myocardial fibrosis can lead to ischemic damage of the myocardium, which can be life-threatening in severe cases. Cardiac fibroblast (CF) transdifferentiation is an important process in myocardial fibrosis. Fucoxanthin (FX) plays a key role in ameliorating myocardial fibrosis; however, its mechanism of action is not fully understood. This study investigated the role of FX in the angiotensin II (Ang II)-induced transdifferentiation of CFs and its potential mechanisms of action. We found that FX inhibited Ang II-induced transdifferentiation of CFs. Simultaneously, FX downregulated bromodomain-containing protein 4 (BRD4) expression in CFs and increased nuclear expression of nuclear factorerythroid 2-related factor 2 (Nrf2). FX reverses AngII-induced inhibition of the Keap1/Nrf2/HO-1 pathway and elevates the level of reactive oxygen species (ROS). FX failed to reverse Ang II-induced changes in fibrosis-associated proteins and ROS levels after Nrf2 silencing. BRD4 silencing reversed the inhibitory effect of Ang II on the Keap1/Nrf2/HO-1 antioxidant signalling pathway. In conclusion, we demonstrated that FX inhibited Ang II-induced transdifferentiation of CFs and that this effect may be related to the activation of the Keap1/Nrf2/HO-1 pathway by reducing BRD4 expression and, ultimately, oxidative stress.

Qidan Tiaozhi capsule attenuates metabolic syndrome via activating AMPK/PINK1-Parkin-mediated mitophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Qidan Tiaozhi capsule (QD), a traditional Chinese medicine, has been used to treat metabolic syndrome for over a decade. However, the mechanism of QD in the treatment of metabolic syndrome is still unknown.

AIM OF THE STUDY

Growing studies demonstrate that impaired mitophagy is one of the important causes of metabolic syndrome. Thus, this research aims to investigate the mechanism of mitophagy in the QD treatment of metabolic syndrome.

MATERIALS AND METHODS

Network pharmacology and molecular docking were used to probe the mechanism of QD treatment of metabolic syndrome. In an oleic acid-induced cell model, glucose consumption and uptake capacity, triglyceride (TG), total cholesterol (TC), malonaldehyde (MDA), superoxide dismutase (SOD) and ROS levels, and mitochondrial membrane potential (MMP) were examined. mRFP-GFP-LC3 adenovirus and GFP-LC3 lentivirus were used to examine the effect of QD on mitophagy. The IRS2-PI3K and AMPK/PINK1-Parkin signal pathways were also determined. What's more, the PINK1 gene was silenced to verify the above findings. In a high-fat diet-fed mouse model, body weight, organ indexes, OGTT, ITT, HOMA-IR, insulin sensitivity, serum MDA, SOD, TC, TG, LDL-C and HDL-C, hepatic TC, TG, LDL-C and HDL-C levels, hepatic steatosis, and IRS2-PI3K and AMPK/PINK1-Parkin signal pathways were investigated.

RESULTS

Results from network pharmacology and molecular docking suggested that QD might suppress oxidative stress to improve metabolic syndrome. In an oleic acid-induced cell model, compared with the model group, enhanced glucose consumption and uptake ability, inhibited intracellular lipid accumulation, TC, TG, MDA and ROS levels, and increased SOD level and MMP were found in QD groups. And mitophagy levels, IRS2-PI3K and AMPK/PINK1-Parkin signal pathways were promoted. Interestingly, PINK1 silencing reversed the therapeutic action of QD on oleic acid-induced cells. In high-fat diet-fed mice, inhibited body weight, abdominal fat indexes, liver indexes, HOMA-IR, serum and hepatic TC, TG and LDL-C, serum MDA and hepatic steatosis, and increased insulin sensitivity, serum and hepatic HDL-C, serum SOD, and activated IRS2-PI3K and AMPK/PINK1-Parkin signal pathways were found in QD groups.

CONCLUSION

QD activates AMPK/PINK1-Parkin-mediated mitophagy to suppress oxidative stress to treat metabolic syndrome.

The Role of Fucoxanthin in Non-Alcoholic Fatty Liver Disease

Chronic liver disease (CLD) has emerged as a leading cause of human deaths. It caused 1.32 million deaths in 2017, which affected men more than women by a two-to-one ratio. There are various causes of CLD, including obesity, excessive alcohol consumption, and viral infection. Among them, non-alcoholic fatty liver disease (NAFLD), one of obesity-induced liver diseases, is the major cause, representing the cause of more than 50% of cases. Fucoxanthin, a carotenoid mainly found in brown seaweed, exhibits various biological activities against NAFLD. Its role in NAFLD appears in several mechanisms, such as inducing thermogenesis in mitochondrial homeostasis, altering lipid metabolism, and promoting anti-inflammatory and anti-oxidant activities. The corresponding altered signaling pathways are the β3-adorenarine receptor (β3Ad), proliferator-activated receptor gamma coactivator (PGC-1), adenosine monophosphate-activated protein kinase (AMPK), peroxisome proliferator-activated receptor (PPAR), sterol regulatory element binding protein (SREBP), nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), protein kinase B (AKT), SMAD2/3, and P13K/Akt pathways. Fucoxanthin also exhibits anti-fibrogenic activity that prevents non-alcoholic steatohepatitis (NASH) development.

The protection of luteolin against diabetic cardiomyopathy in rats is related to reversing JNK-suppressed autophagy

Increasing evidence has shown that impaired autophagy dramatically causes myocardial hypertrophy and fibrosis in the diabetic heart, ultimately leading to diabetic cardiomyopathy (DCM). Luteolin has been reported to effectively attenuate diabetic cardiovascular injury by inhibiting oxidative stress and alleviate sepsis-induced myocardial injury by enhancing autophagy. However, whether luteolin can reduce DCM through activating autophagy and the underlying mechanism remain unclear. Here, reversing the c-Jun N-terminal kinase (JNK)-suppressed autophagy pathway by which luteolin attenuates DCM was explored. Male Sprague-Dawley rats were injected with streptozotocin to induce diabetes. After 6 weeks of diabetes, rats were treated with luteolin (50, 100 and 200 mg kg-1, i.g.) for 4 weeks. Histological and functional alterations in the diabetic heart were determined using HE staining, Masson staining and echocardiography. The expressions of myocardial miR-221, JNK, and c-Jun and autophagic vesicles in diabetes were evaluated by quantitative PCR, Western blotting and electron microscopy. Luteolin significantly improved cardiac function and attenuated myocardial disorganization and fibrosis in the diabetic rat accompanying the dose-dependent down-regulation of JNK, c-Jun, miR-221 and p62, increase of LC3-II/I and autophagic vesicles, and decrease of mitochondrial swelling in the diabetic heart. These data suggest that the protection of luteolin against DCM, at least, is related to suppressing JNK/c-Jun-regulated miR-221 and the subsequent blockage of autophagy.

Microplastics Exacerbate Cadmium-Induced Kidney Injury by Enhancing Oxidative Stress, Autophagy, Apoptosis, and Fibrosis

Cadmium (Cd) is a potential pathogenic factor in the urinary system that is associated with various kidney diseases. Microplastics (MPs), comprising of plastic particles less than 5 mm in diameter, are a major carrier of contaminants. We applied 10 mg/L particle 5 μm MPs and 50 mg/L CdCl2 in water for three months in vivo assay to assess the damaging effects of MPs and Cd exposure on the kidney. In vivo tests showed that MPs exacerbated Cd-induced kidney injury. In addition, the involvement of oxidative stress, autophagy, apoptosis, and fibrosis in the damaging effects of MPs and Cd on mouse kidneys were investigated. The results showed that MPs aggravated Cd-induced kidney injury by enhancing oxidative stress, autophagy, apoptosis, and fibrosis. These findings provide new insights into the toxic effects of MPs on the mouse kidney.