Salidroside protects cardiac function in mice with diabetic cardiomyopathy via activation of mitochondrial biogenesis and SIRT3

Tinglu Yixin granule inhibited fibroblast-myofibroblast transdifferentiation to ameliorate myocardial fibrosis in diabetic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Myocardial fibrosis is one of the pathological characteristics of advanced diabetic cardiomyopathy (DCM) and serves as the strong evidence of poor prognosis. Among them, the transdifferentiation of cardiac fibroblasts (CFs) may play a crucial role in the development of myocardial fibrosis in DCM. Tinglu Yixin granule (TLYXG) has been clinically used for many years and can significantly improve cardiac function of patients with DCM. However, the effect of TLYXG on myocardial fibrosis in DCM remains unknown, and the underlying mechanisms of its efficacy have yet to be fully understood.

AIM OF THE STUDY

This study aimed to investigate the impact and underlying mechanism of TLYXG on myocardial fibrosis in diabetes mice.

MATERIALS AND METHODS

The bioactive compounds in TLYXG were identified using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). The potential mechanism of TLYXG in treating DCM was predicted using network pharmacology combined with molecular docking and protein-protein docking. The mice model of type 2 diabetes were established by intraperitoneal injection of streptozotocin (STZ) and the high-fat diet (HFD). Indicators of pancreatic islet function, lipids, oxidative stress, and inflammatory factors were tested using kits. Cardiac function was assessed in diabetic mice using echocardiography. Histologic staining was performed to evaluate myocardial hypertrophy and fibrosis. Mechanistically, the hypothesis was tested through rescue experiments. The expression levels of transient receptor potential channel 6 (TRPC6), transforming growth factor-β1 (TGF-β1), collagen I (COL-I) and alpha-smooth muscle actin (α-SMA), along with the mRNA and phosphorylation levels of SMAD family member 3 (Smad3) and protein 38 mitogen-activated protein kinase (p38 MAPK), were assessed using quantitative RT-qPCR, Western blot, immunohistochemistry, and immunofluorescence. Neonatal lactating mice were used to extract primary CFs for vitro experiments. Scratch and transwell assays were conducted to assess CFs migration and invasion abilities. Western blot and immunofluorescence were used to evaluate the expression levels of CFs transdifferentiation markers COL-I and α-SMA.

RESULTS

A total of 168 active ingredients were detected in TLYXG based on UPLC-MS and databases. Network pharmacology indicated that TLYXG could improve DCM through inflammatory mediator regulation of TRP channels, TGF-beta signaling pathway, and MAPK signaling pathway. ELISA results showed that TLYXG could ameliorate metabolic levels, inflammation, and oxidative stress in diabetic mice. Echocardiography suggested that TLYXG improved cardiac systolic and diastolic dysfunction in diabetic mice. Histological analysis revealed that TLYXG alleviated myocardial fibrosis in diabetes mice. Additionally, molecular docking analysis indicated strong binding activity between the main active ingredients of TLYXG and TRPC6 of the TRP family. At the molecular level, TLYXG reduced the mRNA and protein expression levels of TRPC6 and TGF-β1 and inhibited the mRNA and phosphorylation levels of Smad3 and p38 MAPK. Furthermore, TLYXG inhibited CFs migration and invasion, and reduced the expression levels of the CFs transdifferentiation markers COL-I and α-SMA.

CONCLUSION

TLYXG inhibited the proliferation, migration, invasion and transdifferentiation of CFs by suppressing TGF-β1/Smad3/p38 MAPK signaling through down-regulation of TRPC6, thereby ameliorating myocardial fibrosis in diabetes mice.

Ferroptosis: Latest evidence and perspectives on plant-derived natural active compounds mitigating doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is a chemotherapy drug widely used in clinical settings, acting as a first-line treatment for various malignant tumors. However, its use is greatly limited by the cardiotoxicity it induces, including doxorubicin-induced cardiomyopathy (DIC). The mechanisms behind DIC are not fully understood, but its potential biological mechanisms are thought to include oxidative stress, inflammation, energy metabolism disorders, mitochondrial damage, autophagy, apoptosis, and ferroptosis. Recent studies have shown that cardiac injury induced by DOX is closely related to ferroptosis. Due to their high efficacy, availability, and low side effects, natural medicine treatments hold strong clinical potential. Currently, natural medicines have been shown to mitigate DOX-induced ferroptosis and ease DIC through various functions such as antioxidation, iron ion homeostasis correction, lipid metabolism regulation, and mitochondrial function improvement. Therefore, this review summarizes the mechanisms of ferroptosis in DIC and the regulation by natural plant products, with the expectation of providing a reference for future research and development of inhibitors targeting ferroptosis in DIC. This review explores the mechanisms of ferroptosis in doxorubicin-induced cardiomyopathy (DIC) and summarizes how natural plant products can alleviate DIC by inhibiting ferroptosis through reducing oxidative stress, correcting iron ion homeostasis, regulating lipid metabolism, and improving mitochondrial function.

Salidroside treatment decreases the susceptibility of atrial fibrillation in diabetic mice by reducing mTOR-STAT3-MCP-1 signaling and atrial inflammation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinic, and type 2 diabetes mellitus (T2DM) is an independent risk factor for AF. Salidroside (Sal), the active ingredient of the Rhodiola rosea, has hypoglycemic, anti-inflammatory, anti-fibrotic and anti-arrhythmic effects. The aim of this study is to investigate the effects and underlying molecular mechanisms of Sal on T2DM associated atrial inflammation and the pathogenesis of AF. In the in vivo study, T2DM mice model was established by high-fat diet and intraperitoneal injection of streptozotocin (STZ). Sal (25 mg/kg/d, 50 mg/kg/d, and 100 mg/kg/d) was administered orally for 4 weeks. T2DM caused atrial electrical and structural remodeling and significantly increased the susceptibility of AF. Meanwhile, mTOR-STAT3-MCP-1 signaling and inflammatory markers were also significantly enhanced in diabetic atria. However, Sal dose-dependently ameliorated cardiac dysfunction, mitigated atrial structural and electrical remodeling, and reduced atrial inflammation. Moreover, Sal-treated group exhibited remarkably down-regulated activity of mTOR-STAT3-MCP-1 pathway, and decreased atrial monocyte/macrophage infiltration. In palmitic acid (PA)-challenged HL-1 cells, Sal attenuated cytotoxicity, downregulated the expressions of TNF-α, IL-6, MCP-1, and inhibited the activation of mTOR-STAT3 signaling. However, co-treatment with MHY1485 (a mTOR agonist) reversed these effects. Taken together, the present study demonstrates that Sal treatment decreases the susceptibility of AF in diabetic mice by reducing mTOR-STAT3-MCP-1 signaling and atrial monocyte/macrophage infiltration. Sal treatment may represent a novel preventive therapy for cardiac arrhythmia and atrial fibrillation in diabetic patients.

The Cardiovascular Protective Function of Natural Compounds Through AMPK/SIRT1/PGC-1α Signaling Pathway

Cardiovascular disease (CVD) poses a major risk to human health and exert a heavy burden on individuals, society, and healthcare systems. Therefore, it is critical to identify CVD's underlying mechanism(s) and target them using effective agents. Natural compounds have shown promise as antioxidants with cardioprotective functions against CVD injuries due to their antioxidative solid capacity and high safety profile. Several CVDs, such as heart failure, ischemia/reperfusion, atherosclerosis, and cardiomyopathies, are closely linked to mitochondrial dysfunction. It is well established that activating the AMPK/SIRT1/PGC-1α pathway during CVD promotes mitochondrial function. Therefore, targeting the AMPK/SIRT1/PGC-1α pathway provides a foundation for novel therapeutic strategies to combat CVD. A key goal of our search was to find natural compounds that target this biological pathway and have beneficial effects on CVD.

Cardiomyocyte LGR6 alleviates ferroptosis in diabetic cardiomyopathy via regulating mitochondrial biogenesis

AIMS

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

METHODS AND RESULTS

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

CONCLUSIONS

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

α-Arbutin ameliorates UVA-induced photoaging through regulation of the SIRT3/PGC-1α pathway

Owing to its tyrosinase inhibitory activity, α-arbutin has been added to several skin care products as a skin-lightening agent. However, the protective effect of α-arbutin against ultraviolet A (UVA)-induced photoaging has not been well investigated. The present study was designed to investigate the photoprotective effect and mechanism of α-arbutin against UVA-induced photoaging. In vitro experiments, HaCaT cells were treated with UVA at a dose of 3 J/cm2 to evaluate the anti-photoaging effect of α-arbutin. α-Arbutin was found to exhibit a strong antioxidant effect by increasing glutathione (GSH) level and inhibiting reactive oxygen species (ROS) production. Meanwhile, α-arbutin markedly improved the expression of sirtuin 3 (SIRT3) and peroxisome proliferator-activated receptor γ coactivator 1 α (PGC-1α) proteins, initiating downstream signaling to increase mitochondrial membrane potential and mediate mitochondrial biogenesis, and improve mitochondrial structure significantly. In vivo analysis, the mice with shaved back hair were irradiated with a cumulative UVA dose of 10 J/cm2 and a cumulative ultraviolet B (UVB) dose of 0.63 J/cm2. The animal experiments demonstrated that α-arbutin increased the expression of SIRT3 and PGC-1α proteins in the back skin of mice, thereby reducing UV-induced skin damage. In conclusion, α-arbutin protects HaCaT cells and mice from UVA damage by regulating SIRT3/PGC-1α signaling pathway.

Farrerol Alleviates Diabetic Cardiomyopathy by Regulating AMPK-Mediated Cardiac Lipid Metabolic Pathways in Type 2 Diabetic Rats

Diabetic cardiomyopathy (DCM) is a prevalent complication of diabetes mellitus characterized by cardiac dysfunction and myocardial remodeling. Farrerol (FA), an active ingredient in Rhododendron with various pharmacological activities, has an unclear specific role in DCM. Therefore, this study aims to investigate the effects of FA on DCM rats and elucidate its mechanism. The type 2 diabetes mellitus (T2DM) model was induced in adult male Sprague-Dawley rats by administering a high-fat diet for 8 weeks along with STZ injection. Subsequent to successful modeling, FA and the positive drug Dapagliflozin (Dapa) were orally administered via gavage for an additional 8-week period. After administration, the rats' body weight, fasting blood glucose, fasting insulin, and blood lipid profiles were quantified. Cardiac function was assessed through evaluation of cardiac function parameters, histopathological examination and measurement of myocardial enzyme markers were conducted to assess myocardial injury and fibrosis, Oil red O staining was utilized to evaluate myocardial lipid accumulation, wheat germ agglutinin (WGA) staining was used for assessing cardiomyocyte hypertrophy, and Western blot analysis was used to detect the proteins expression level of AMP-activated protein kinase (AMPK) pathway. The rat cardiomyocyte H9c2 were induced with palmitic acid to establish an in vitro cell model of myocardial lipid toxicity. Subsequently, the cells were subjected to treatment with FA and AMPK inhibitor Compound C, followed by assessment of lipid formation and expression levels of proteins related to the AMPK signaling pathway. The findings demonstrated that both FA and Dapa exhibited efficacy in ameliorating diabetic symptoms, cardiac dysfunction, myocardial fibrosis, cardiomyocyte hypertrophy, and lipid accumulation in T2DM rats. Additionally, they were found to enhance AMPK phosphorylation and PPARα expression while down-regulating CD36. Similarly, FA was observed to inhibit lipid formation in H9c2 and activate the AMPK signaling pathway. However, the improved effect of FA on lipotoxic cardiomyocytes induced by palmitic acid was partially reversed by Compound C. Therefore, the activation of the AMPK signaling pathway by FA may enhance cardiac lipid metabolism, thereby improving cardiac dysfunction and myocardial fibrosis in DCM rats.

Diabetes cardiomyopathy: targeted regulation of mitochondrial dysfunction and therapeutic potential of plant secondary metabolites

Diabetic cardiomyopathy (DCM) is a specific heart condition in diabetic patients, which is a major cause of heart failure and significantly affects quality of life. DCM is manifested as abnormal cardiac structure and function in the absence of ischaemic or hypertensive heart disease in individuals with diabetes. Although the development of DCM involves multiple pathological mechanisms, mitochondrial dysfunction is considered to play a crucial role. The regulatory mechanisms of mitochondrial dysfunction mainly include mitochondrial dynamics, oxidative stress, calcium handling, uncoupling, biogenesis, mitophagy, and insulin signaling. Targeting mitochondrial function in the treatment of DCM has attracted increasing attention. Studies have shown that plant secondary metabolites contribute to improving mitochondrial function and alleviating the development of DCM. This review outlines the role of mitochondrial dysfunction in the pathogenesis of DCM and discusses the regulatory mechanism for mitochondrial dysfunction. In addition, it also summarizes treatment strategies based on plant secondary metabolites. These strategies targeting the treatment of mitochondrial dysfunction may help prevent and treat DCM.

Macrod1 suppresses diabetic cardiomyopathy via regulating PARP1-NAD+-SIRT3 pathway

Diabetic cardiomyopathy (DCM), one of the most serious long-term consequences of diabetes, is closely associated with oxidative stress, inflammation and apoptosis in the heart. MACRO domain containing 1 (Macrod1) is an ADP-ribosylhydrolase 1 that is highly enriched in mitochondria, participating in the pathogenesis of cardiovascular diseases. In this study, we investigated the role of Macrod1 in DCM. A mice model was established by feeding a high-fat diet (HFD) and intraperitoneal injection of streptozotocin (STZ). We showed that Macrod1 expression levels were significantly downregulated in cardiac tissue of DCM mice. Reduced expression of Macrod1 was also observed in neonatal rat cardiomyocytes (NRCMs) treated with palmitic acid (PA, 400 μM) in vitro. Knockout of Macrod1 in DCM mice not only worsened glycemic control, but also aggravated cardiac remodeling, mitochondrial dysfunction, NAD+ consumption and oxidative stress, whereas cardiac-specific overexpression of Macrod1 partially reversed these pathological processes. In PA-treated NRCMs, overexpression of Macrod1 significantly inhibited PARP1 expression and restored NAD+ levels, activating SIRT3 to resist oxidative stress. Supplementation with the NAD+ precursor Niacin (50 μM) alleviated oxidative stress in PA-stimulated cardiomyocytes. We revealed that Macrod1 reduced NAD+ consumption by inhibiting PARP1 expression, thereby activating SIRT3 and anti-oxidative stress signaling. This study identifies Macrod1 as a novel target for DCM treatment. Targeting the PARP1-NAD+-SIRT3 axis may open a novel avenue to development of new intervention strategies in DCM. Schematic illustration of macrod1 ameliorating diabetic cardiomyopathy oxidative stress via PARP1-NAD+-SIRT3 axis.

The potential of therapeutic strategies targeting mitochondrial biogenesis for the treatment of insulin resistance and type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a persistent metabolic disorder marked by deficiencies in insulin secretion and/or function, affecting various tissues and organs and leading to numerous complications. Mitochondrial biogenesis, the process by which cells generate new mitochondria utilizing existing ones plays a crucial role in energy homeostasis, glucose metabolism, and lipid handling. Recent evidence suggests that promoting mitochondrial biogenesis can alleviate insulin resistance in the liver, adipose tissue, and skeletal muscle while improving pancreatic β-cell function. Moreover, enhanced mitochondrial biogenesis has been shown to ameliorate T2DM symptoms and may contribute to therapeutic effects for the treatment of diabetic nephropathy, cardiomyopathy, retinopathy, and neuropathy. This review summarizes the intricate connection between mitochondrial biogenesis and T2DM, highlighting the potential of novel therapeutic strategies targeting mitochondrial biogenesis for T2DM treatment and its associated complications. It also discusses several natural products that exhibit beneficial effects on T2DM by promoting mitochondrial biogenesis.

A review on SIRT3 and its natural small molecule activators as a potential Preventive and therapeutic target

Sirtuins (SIRTs) were originally characterized by yeast Sir2 as a lifespan regulator that is conserved in all three structural domains of bacteria, archaea and eukaryotes and belong to histone deacetylases consisting of seven members (SIRT1-SIRT7). Surprisingly, SIRTs have been shown to play important regulatory roles in almost all cellular functions, including mitochondrial biogenesis, oxidative stress, inflammation, cell growth, energy metabolism, neural function, and stress resistance. Among the SIRT members, sirtuin 3 (SIRT3) is one of the most important deacetylases that regulates the mitochondrial acetylation and plays a role in pathological processes, such as metabolism, DNA repair, oxidative stress, apoptosis and ferroptosis. Therefore, SIRT3 is considered as a potential target for the treatment of a variety of pathological diseases, including metabolic diseases, neurodegenerative diseases, age-related diseases and others. Furthermore, the isolation, screening, and development of SIRT3 signaling agonists, especially from natural products, have become a widely investigated objective. This paper describes the structure of SIRT3 protein, discusses the pathological process of SIRT3-mediated acetylation modification, and reviews the role of SIRT3 in diseases, SIRT3 activators and its related disease studies.

SIRT3 regulates mitochondrial function: A promising star target for cardiovascular disease therapy

Dysregulation of mitochondrial homeostasis is common to all types of cardiovascular diseases. SIRT3 regulates apoptosis and autophagy, material and energy metabolism, mitochondrial oxidative stress, inflammation, and fibrosis. As an important mediator and node in the network of mechanisms, SIRT3 is essential to many activities. This review explains how SIRT3 regulates mitochondrial homeostasis and the tricarboxylic acid cycle to treat common cardiovascular diseases. A novel description of the impact of lifestyle factors on SIRT3 expression from the angles of nutrition, exercise, and temperature is provided.

Targeting mitochondrial quality control for diabetic cardiomyopathy: Therapeutic potential of hypoglycemic drugs

Diabetic cardiomyopathy is a chronic cardiovascular complication caused by diabetes that is characterized by changes in myocardial structure and function, ultimately leading to heart failure and even death. Mitochondria serve as the provider of energy to cardiomyocytes, and mitochondrial dysfunction plays a central role in the development of diabetic cardiomyopathy. In response to a series of pathological changes caused by mitochondrial dysfunction, the mitochondrial quality control system is activated. The mitochondrial quality control system (including mitochondrial biogenesis, fusion and fission, and mitophagy) is core to maintaining the normal structure of mitochondria and performing their normal physiological functions. However, mitochondrial quality control is abnormal in diabetic cardiomyopathy, resulting in insufficient mitochondrial fusion and excessive fission within the cardiomyocyte, and fragmented mitochondria are not phagocytosed in a timely manner, accumulating within the cardiomyocyte resulting in cardiomyocyte injury. Currently, there is no specific therapy or prevention for diabetic cardiomyopathy, and glycemic control remains the mainstay. In this review, we first elucidate the pathogenesis of diabetic cardiomyopathy and explore the link between pathological mitochondrial quality control and the development of diabetic cardiomyopathy. Then, we summarize how clinically used hypoglycemic agents (including sodium-glucose cotransport protein 2 inhibitions, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, thiazolidinediones, metformin, and α-glucosidase inhibitors) exert cardioprotective effects to treat and prevent diabetic cardiomyopathy by targeting the mitochondrial quality control system. In addition, the mechanisms of complementary alternative therapies, such as active ingredients of traditional Chinese medicine, exercise, and lifestyle, targeting mitochondrial quality control for the treatment of diabetic cardiomyopathy are also added, which lays the foundation for the excavation of new diabetic cardioprotective drugs.

Chinese herbal medicine and active ingredients for diabetic cardiomyopathy: molecular mechanisms regulating endoplasmic reticulum stress

Background: Diabetic cardiomyopathy (DCM) is one of the serious microvascular complications of diabetes mellitus. It is often associated with clinical manifestations such as arrhythmias and heart failure, and significantly reduces the quality of life and years of survival of patients. Endoplasmic reticulum stress (ERS) is the removal of unfolded and misfolded proteins and is an important mechanism for the maintenance of cellular homeostasis. ERS plays an important role in the pathogenesis of DCM by causing cardiomyocyte apoptosis, insulin resistance, calcium imbalance, myocardial hypertrophy and fibrosis. Targeting ERS is a new direction in the treatment of DCM. A large number of studies have shown that Chinese herbal medicine and active ingredients can significantly improve the clinical outcome of DCM patients through intervention in ERS and effects on myocardial structure and function, which has become one of the hot research directions. Purpose: The aim of this review is to elucidate and summarize the roles and mechanisms of Chinese herbal medicine and active ingredients that have the potential to modulate endoplasmic reticulum stress, thereby contributing to better management of DCM. Methods: Databases such as PubMed, Web of Science, China National Knowledge Internet, and Wanfang Data Knowledge Service Platform were used to search, analyze, and collect literature, in order to review the mechanisms by which phytochemicals inhibit the progression of DCM by targeting the ERS and its key signaling pathways. Keywords used included "diabetic cardiomyopathy" and "endoplasmic reticulum stress." Results: This review found that Chinese herbs and their active ingredients can regulate ERS through IRE1, ATF6, and PERK pathways to reduce cardiomyocyte apoptosis, ameliorate myocardial fibrosis, and attenuate myocardial hypertrophy for the treatment of DCM. Conclusion: A comprehensive source of information on potential ERS inhibitors is provided in this review. The analysis of the literature suggests that Chinese herbal medicine and its active ingredients can be used as potential drug candidates for the treatment of DCM. In short, we cannot ignore the role of traditional Chinese medicine in regulating ERS and treating DCM, and look forward to more research and new drugs to come.

The role of mitochondria in myocardial damage caused by energy metabolism disorders: From mechanisms to therapeutics

Myocardial damage is the most serious pathological consequence of cardiovascular diseases and an important reason for their high mortality. In recent years, because of the high prevalence of systemic energy metabolism disorders (e.g., obesity, diabetes mellitus, and metabolic syndrome), complications of myocardial damage caused by these disorders have attracted widespread attention. Energy metabolism disorders are independent of traditional injury-related risk factors, such as ischemia, hypoxia, trauma, and infection. An imbalance of myocardial metabolic flexibility and myocardial energy depletion are usually the initial changes of myocardial injury caused by energy metabolism disorders, and abnormal morphology and functional destruction of the mitochondria are their important features. Specifically, mitochondria are the centers of energy metabolism, and recent evidence has shown that decreased mitochondrial function, caused by an imbalance in mitochondrial quality control, may play a key role in myocardial injury caused by energy metabolism disorders. Under chronic energy stress, mitochondria undergo pathological fission, while mitophagy, mitochondrial fusion, and biogenesis are inhibited, and mitochondrial protein balance and transfer are disturbed, resulting in the accumulation of nonfunctional and damaged mitochondria. Consequently, damaged mitochondria lead to myocardial energy depletion and the accumulation of large amounts of reactive oxygen species, further aggravating the imbalance in mitochondrial quality control and forming a vicious cycle. In addition, impaired mitochondria coordinate calcium homeostasis imbalance, and epigenetic alterations participate in the pathogenesis of myocardial damage. These pathological changes induce rapid progression of myocardial damage, eventually leading to heart failure or sudden cardiac death. To intervene more specifically in the myocardial damage caused by metabolic disorders, we need to understand the specific role of mitochondria in this context in detail. Accordingly, promising therapeutic strategies have been proposed. We also summarize the existing therapeutic strategies to provide a reference for clinical treatment and developing new therapies.

Salidroside alleviates diet-induced obesity and insulin resistance by activating Nrf2/ARE pathway and enhancing the thermogenesis of adipose tissues

Recent reports suggest that salidroside protects cardiomyocytes from oxidative injury and stimulates glucose uptake by skeletal muscle cells. Despite these findings, the therapeutic potential of salidroside in the treatment of obesity and insulin resistance remains uncertain and requires further investigation. In the present study, the treatment effect of salidroside on the onset and development of the obese phenotype and insulin resistance as well as the underlying mechanisms was investigated using long-term high-fat diet-induced obese mice supplemented with salidroside. We used biochemical kits to determine serum biochemical parameters (including triacylglycerol, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting glucose, and insulin). The results show that salidroside-supplemented animals showed better glucose tolerance and insulin sensitivity, decreased blood lipids, and weight gain (p < .05). Protein expression of p-Nrf2 and Nrf2 was analyzed by western blotting, and the mRNA levels of thermogenic-related genes (Ucp1, Pgc1a, Prdm16, and Cidea) were detected by quantitative RT-PCR. The results show an improvement in lipid peroxidation and Nrf2/ARE signaling, as well as an increased expression of the Ucp1, Pgc1a, Prdm16, and Cidea (p < .05). Our evidence suggests that salidroside alleviates diet-induced obesity and insulin resistance potentially by activating Nrf2/ARE pathway and enhancing the thermogenesis of adipose tissues. This induction represents a potential technique for the management of comorbidities related to obesity and its prevention.

The Chinese herbal medicine Fufang Zhenzhu Tiaozhi ameliorates diabetic cardiomyopathy by regulating cardiac abnormal lipid metabolism and mitochondrial dynamics in diabetic mice

Diabetic cardiomyopathy (DCM) is an important complication leading to the death of patients with diabetes, but there is no effective strategy for clinical treatments. Fufang Zhenzhu Tiaozhi (FTZ) is a patent medicine that is a traditional Chinese medicine compound preparation with comprehensive effects for the prevention and treatment of glycolipid metabolic diseases under the guidance of "modulating liver, starting pivot and cleaning turbidity". FTZ was proposed by Professor Guo Jiao and is used for the clinical treatment of hyperlipidemia. This study was designed to explore the regulatory mechanisms of FTZ on heart lipid metabolism dysfunction and mitochondrial dynamics disorder in mice with DCM, and it provides a theoretical basis for the myocardial protective effect of FTZ in diabetes. In this study, we demonstrated that FTZ protected heart function in DCM mice and downregulated the overexpression of free fatty acids (FFAs) uptake-related proteins cluster of differentiation 36 (CD36), fatty acid binding protein 3 (FABP3) and carnitine palmitoyl transferase 1 (CPT1). Moreover, FTZ treatment showed a regulatory effect on mitochondrial dynamics by inhibiting mitochondrial fission and promoting mitochondrial fusion. We also identified in vitro that FTZ could restore lipid metabolism-related proteins, mitochondrial dynamics-related proteins and mitochondrial energy metabolism in PA-treated cardiomyocytes. Our study indicated that FTZ improves the cardiac function of diabetic mice by attenuating the increase in fasting blood glucose levels, inhibiting the decrease in body weight, alleviating disordered lipid metabolism, and restoring mitochondrial dynamics and myocardial apoptosis in diabetic mouse hearts.

The lncRNA HOTAIR attenuates pyroptosis of diabetic cardiomyocytes by recruiting FUS to regulate SIRT3 expression

Diabetic cardiomyopathy (DCM) is a serious cardiovascular complication of diabetes that severely affects the quality of life of diabetic patients. Long noncoding RNAs (lncRNAs) play important roles in the pathogenesis of DCM. However, the role of the lncRNA homeobox transcript antisense RNA (HOTAIR) in the progression of DCM remains unclear. The present study aimed to investigate the role of HOTAIR in high glucose (HG)-induced pyroptosis in cardiomyocytes. The expression of the lncRNA HOTAIR, FUS, and SIRT3 in H9C2 cardiomyocytes was detected by RT-qPCR. Western blotting was used to evaluate the expression of FUS and SIRT3 as well as that of pyroptosis- and inflammation-related proteins. RT-qPCR and ELISA were used to determine the expression and secretion of IL-1β and IL-18. RNA pulldown and RIP experiments were used to validate the binding relationship among HOTAIR, FUS, and SIRT3. Flow cytometry was performed to detect pyroptosis. HG induced pyroptosis and elevated the expression of proteins associated with pyroptosis and inflammation (NLRP3, GSDMD-N, cleaved caspase-1, IL-1β, and IL-18) in cardiomyocytes. HOTAIR and SIRT3 levels were decreased in HG-exposed H9C2 cells. Additionally, overexpression of HOTAIR inhibited the HG-induced pyroptosis and inflammatory response in cardiomyocytes. HOTAIR upregulated SIRT3 expression in H9C2 cells by targeting FUS. Moreover, SIRT3 upregulation suppressed HG-mediated pyroptosis of cardiomyocytes. Notably, SIRT3 depletion reversed the inhibitory effect of HOTAIR on HG-triggered pyroptosis in cardiomyocytes. Our research indicates that HOTAIR alleviates pyroptosis in diabetic cardiomyocytes through the FUS/SIRT3 axis, providing a potential marker for the diagnosis and treatment of DCM.

A Promising Strategy to Treat Neurodegenerative Diseases by SIRT3 Activation

SIRT3, the primary mitochondrial deacetylase, regulates the functions of mitochondrial proteins including metabolic enzymes and respiratory chain components. Although SIRT3's functions in peripheral tissues are well established, the significance of its downregulation in neurodegenerative diseases is beginning to emerge. SIRT3 plays a key role in brain energy metabolism and provides substrate flexibility to neurons. It also facilitates metabolic coupling between fuel substrate-producing tissues and fuel-consuming tissues. SIRT3 mediates the health benefits of lifestyle-based modifications such as calorie restriction and exercise. SIRT3 deficiency is associated with metabolic syndrome (MetS), a precondition for diseases including obesity, diabetes, and cardiovascular disease. The pure form of Alzheimer's disease (AD) is rare, and it has been reported to coexist with these diseases in aging populations. SIRT3 downregulation leads to mitochondrial dysfunction, neuroinflammation, and inflammation, potentially triggering factors of AD pathogenesis. Recent studies have also suggested that SIRT3 may act through multiple pathways to reduce plaque formation in the AD brain. In this review, we give an overview of SIRT3's roles in brain physiology and pathology and discuss several activators of SIRT3 that can be considered potential therapeutic agents for the treatment of dementia.

Targeting ferroptosis as a promising therapeutic strategy to treat cardiomyopathy

Cardiomyopathies are a clinically heterogeneous group of cardiac diseases characterized by heart muscle damage, resulting in myocardium disorders, diminished cardiac function, heart failure, and even sudden cardiac death. The molecular mechanisms underlying the damage to cardiomyocytes remain unclear. Emerging studies have demonstrated that ferroptosis, an iron-dependent non-apoptotic regulated form of cell death characterized by iron dyshomeostasis and lipid peroxidation, contributes to the development of ischemic cardiomyopathy, diabetic cardiomyopathy, doxorubicin-induced cardiomyopathy, and septic cardiomyopathy. Numerous compounds have exerted potential therapeutic effects on cardiomyopathies by inhibiting ferroptosis. In this review, we summarize the core mechanism by which ferroptosis leads to the development of these cardiomyopathies. We emphasize the emerging types of therapeutic compounds that can inhibit ferroptosis and delineate their beneficial effects in treating cardiomyopathies. This review suggests that inhibiting ferroptosis pharmacologically may be a potential therapeutic strategy for cardiomyopathy treatment.

Salidroside Ameliorates Ultraviolet-Induced Keratinocyte Injury by Inducing SIRT1-Dependent Autophagy

Introduction

Methods

Results

Discussion

The Role of Mitochondrial Biogenesis Dysfunction in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is described as abnormalities of myocardial structure and function in diabetic patients without other well-established cardiovascular factors. Although multiple pathological mechanisms involving in this unique myocardial disorder, mitochondrial dysfunction may play an important role in its development of DCM. Recently, considerable progresses have suggested that mitochondrial biogenesis is a tightly controlled process initiating mitochondrial generation and maintaining mitochondrial function, appears to be associated with DCM. Nonetheless, an outlook on the mechanisms and clinical relevance of dysfunction in mitochondrial biogenesis among patients with DCM is not completely understood. In this review, hence, we will summarize the role of mitochondrial biogenesis dysfunction in the development of DCM, especially the molecular underlying mechanism concerning the signaling pathways beyond the stimulation and inhibition of mitochondrial biogenesis. Additionally, the evaluations and potential therapeutic strategies regarding mitochondrial biogenesis dysfunction in DCM is also presented.

Emerging Roles of SIRT3 in Cardiac Metabolism

The heart is a highly metabolically active organ that predominantly utilizes fatty acids as an energy substrate. The heart also derives some part of its energy by oxidation of other substrates, including glucose, lactose, amino acids and ketones. The critical feature of cardiac pathology is metabolic remodeling and loss of metabolic flexibility. Sirtuin 3 (SIRT3) is one of the seven mammalian sirtuins (SIRT1 to SIRT7), with NAD⁺ dependent deacetylase activity. SIRT3 is expressed in high levels in healthy hearts but downregulated in the aged or diseased hearts. Experimental evidence shows that increasing SIRT3 levels or activity can ameliorate several cardiac pathologies. The primary deacetylation targets of SIRT3 are mitochondrial proteins, most of which are involved in energy metabolism. Thus, SIRT3 improves cardiac health by modulating cardiac energetics. In this review, we discuss the essential role of SIRT3 in regulating cardiac metabolism in the context of physiology and pathology. Specifically, we summarize the recent advancements that emphasize the critical role of SIRT3 as a master regulator of cardiac metabolism. We also present a comprehensive view of all known activators of SIRT3, and elaborate on their therapeutic potential to ameliorate energetic abnormalities in various cardiac pathologies.

Rhodiola rosea: A Therapeutic Candidate on Cardiovascular Diseases

Cardiovascular diseases, also known as circulatory diseases, are diseases of the heart and blood vessels, and its etiology is hyperlipidemia, thick blood, atherosclerosis, and hypertension. Due to its high prevalence, disability, and mortality, it seriously threatens human health. According to reports, the incidence of cardiovascular disease is still on the rise. Rhodiola rosea is a kind of traditional Chinese medicine, which has the effects of antimyocardial ischemia-reperfusion injury, lowering blood fat, antithrombosis, and antiarrhythmia. Rhodiola rosea has various chemical components, and different chemical elements have the same pharmacological effects and medicinal values for various cardiovascular diseases. This article reviews the research on the pharmacological effects of Rhodiola rosea on cardiovascular diseases and provides references for the clinical treatment of cardiovascular diseases.

Krill Oil Inhibits NLRP3 Inflammasome Activation in the Prevention of the Pathological Injuries of Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is a common complication of diabetes mellitus (DM), resulting in high mortality. Myocardial fibrosis, cardiomyocyte apoptosis and inflammatory cell infiltration are hallmarks of DCM, leading to cardiac dysfunction. To date, few effective approaches have been developed for the intervention of DCM. In the present study, we investigate the effect of krill oil (KO) on the prevention of DCM using a mouse model of DM induced by streptozotocin and a high-fat diet. The diabetic mice developed pathological features, including cardiac fibrosis, apoptosis and inflammatory cell infiltration, the effects of which were remarkably prevented by KO. Mechanistically, KO reversed the DM-induced cardiac expression of profibrotic and proinflammatory genes and attenuated DM-enhanced cardiac oxidative stress. Notably, KO exhibited a potent inhibitory effect on NLR family pyrin domain containing 3 (NLRP3) inflammasome that plays an important role in DCM. Further investigation showed that KO significantly upregulated the expression of Sirtuin 3 (SIRT3) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), which are negative regulators of NLRP3. The present study reports for the first time the preventive effect of KO on the pathological injuries of DCM, providing SIRT3, PGC-1α and NLRP3 as molecular targets of KO. This work suggests that KO supplementation may be a viable approach in clinical prevention of DCM.

Salidroside Affects Gut Microbiota Structure in db/db Mice by Affecting Insulin, Blood Glucose and Body Weight

PURPOSE

The purpose of this study was to investigate the regulatory effect of salidroside on the intestinal flora of mice with type 2 diabetes (T2DM) and its protective effect in the body.

PATIENTS AND METHODS

We acclimated 8-week-old mice for 7 days, divided them into 4 groups, and continued dosing for 8 weeks. We recorded weekly blood glucose levels and body weight for each mouse. After the completion of the feeding cycle, the 16S rRNA of the intestinal flora in the mice was sequenced, and the insulin and C-peptide levels in each group of mice were measured. Four samples were taken from each group for liver and kidney section staining.

RESULTS

Our results showed that gut microbiota diversity and function were significantly different between the diabetic mice and healthy mice and that insulin levels, body weight, and blood glucose levels could significantly influence gut microbiota changes at the genus level. The gut microbiota diversity and function of db/db mice were also altered after salidroside administration. Salidroside could attenuate inflammatory damage, lipid accumulation and inflammatory changes in the diabetic liver, as well as diabetic kidney damage. Candidatus arthromitus and Odoribacter are important species of the microbiota during diabetes and may serve as potential therapeutic targets.

CONCLUSION

Our investigation of the associated pathological conditions and fecal microbiota in db/db mice provides new insights into the pathogenesis of T2DM and provides implications for the diagnosis and treatment of T2DM.

Mitochondrial proteins in heart failure: The role of deacetylation by SIRT3

Heart failure (HF) is still the leading cause of death worldwide, occurring with a variety of complex mechanisms. However, most intervention for HF do not directly target the pathological mechanisms underlying cell damage in failing cardiomyocytes. Mitochondria are involved in many physiological processes, which is an important guarantee for normal heart function. Mitochondrial dysfunction is considered to be the critical node of the development of HF. Strict modulation of the mitochondrial function can ameliorate the myocardial injury and protect cardiac function. Acetylation plays an important role in mitochondrial protein homeostasis, and SIRT3, the most important deacetylation protein in mitochondria, is involved in the maintenance of mitochondrial function. SIRT3 can delay the progression of HF by improving mitochondrial function. Herein we summarize the interaction between SIRT3 and proteins related to mitochondrial function including oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO), mitochondrial biosynthesis, mitochondrial quality control. In addition, we also sum up the effects of this interaction on HF and the research progress of treatments targeting SIRT3, so as to find potential HF therapeutic for clinical use in the future.