Honokiol attenuates high glucose-induced peripheral neuropathy via inhibiting ferroptosis and activating AMPK/SIRT1/PGC-1α pathway in Schwann cells

Advances of traditional Chinese medicine preclinical mechanisms and clinical studies on diabetic peripheral neuropathy

CONTEXT

Diabetic peripheral neuropathy (DPN) results in an enormous burden and reduces the quality of life for patients. Considering there is no specific drug for the management of DPN, traditional Chinese medicine (TCM) has increasingly drawn attention of clinicians and researchers around the world due to its characteristics of multiple targets, active components, and exemplary safety.

OBJECTIVE

To summarize the current status of TCM in the treatment of DPN and provide directions for novel drug development, the clinical effects and potential mechanisms of TCM used in treating DPN were comprehensively reviewed.

METHODS

Existing evidence on TCM interventions for DPN was screened from databases such as PubMed, the Cochrane Neuromuscular Disease Group Specialized Register (CENTRAL), and the Chinese National Knowledge Infrastructure Database (CNKI). The focus was on summarizing and analyzing representative preclinical and clinical TCM studies published before 2023.

RESULTS

This review identified the ameliorative effects of about 22 single herbal extracts, more than 30 herbal compound prescriptions, and four Chinese patent medicines on DPN in preclinical and clinical research. The latest advances in the mechanism highlight that TCM exerts its beneficial effects on DPN by inhibiting inflammation, oxidative stress and apoptosis, endoplasmic reticulum stress and improving mitochondrial function.

CONCLUSIONS

TCM has shown the power latent capacity in treating DPN. It is proposed that more large-scale and multi-center randomized controlled clinical trials and fundamental experiments should be conducted to further verify these findings.

Unraveling the mechanisms underlying diabetic cataracts: insights from Mendelian randomization analysis

BACKGROUND

Diabetic cataract (DC) is a major cause of blindness, with its pathogenesis involving oxidative stress and ferroptosis, according to recent studies.

METHODS

We performed a Mendelian Randomization (MR) study using GWAS data to select SNPs and assess the causal link between diabetes and cataracts. DC datasets were analyzed for differential gene expression, WGCNA, and protein-protein interactions to identify key oxidative stress and ferroptosis genes. An SVM-RFE algorithm developed a diagnostic model, and ImmuCellAI analyzed immune infiltration patterns.

RESULTS

MR analysis confirmed diabetes as a cataract risk factor and identified core genes related to oxidative stress and ferroptosis in DC. Four key genes (Hspa5/Nfe2l2/Atf3/Stat3) linked to both processes were discovered. Immune infiltration analysis revealed an imbalance associated with these genes.

CONCLUSIONS

A functional interaction between oxidative stress and ferroptosis genes in DC is suggested, with a 4-gene model, indicating their potential as a 'bridge' in DC pathogenesis.

Gastrodin alleviates diabetic peripheral neuropathy by regulating energy homeostasis via activating AMPK and inhibiting MMP9

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a serious complication of diabetes that lacks effective treatment. Gastrodin, the primary bioactive compound derived from Rhizoma Gastrodiae, has a long history in treating epilepsy and various central nervous system disorders. However, its effect on DPN remains uncertain.

PURPOSE

This study aims to explore the therapeutic potential and underlying mechanisms of gastrodin in the treatment of DPN.

METHOD

DPN model rats were induced with streptozotocin (STZ) injection and divided into four groups receiving either gastrodin at two doses (30 and 60 mg kg-1 per day), α-lipoic acid (positive drug, 60 mg kg-1 per day), or placebo. Healthy rats were administrated with placebo. The administrations began eight weeks post-STZ injection and continued for six weeks. Following a comprehensive evaluation of the neuroprotective effects, a systematic pharmacology-based approach was subsequently employed to investigate the underlying mechanism of gastrodin in vivo and in vitro.

RESULTS

Gastrodin was demonstrated to effectively enhance peripheral nerve function and reduce pathological damages in DPN rats. Furthermore, gastrodin facilitated the expression of remyelination-related proteins and mitigated oxidative stress in DPN rats. Transcriptomic analysis indicated that the modulation of energy metabolism was pivotal in the neuroprotective effect of gastrodin, corroborated by targeted metabolomic analysis using high-performance ion chromatography coupled with mass spectrometry. Using network pharmacology analysis, 12 potential targets of gastrodin were identified. Among these, matrix metallopeptidase 9 (MMP9) was further validated as the primary target through molecular docking and cellular thermal shift assays. Functional Analysis of the potential targets underscored the pivotal role of AMPK signaling, and gastrodin demonstrated the capability to activate AMPK and inhibit MMP9 in vivo. In vitro studies further found that gastrodin enhanced antioxidant capacity and mitochondrial function of high glucose-cultured rat Schwann cells RSC96 in an AMPK-dependent manner. Inhibition of AMPK hindered the decrease of MMP9 induced by gastrodin in vitro.

CONCLUSION

This study revealed the new role of gastrodin in alleviating DPN by restoring the homeostasis of energy metabolism through activating AMPK and inhibiting MMP9. These findings highlight gastrodin's potential as a novel therapeutic candidate against DPN, and underscores an appealing strategy of regulating energy metabolism for DPN therapy.

SIRT3 alleviates mitochondrial dysfunction and senescence in diabetes-associated periodontitis by deacetylating LRPPRC

Diabetes-associated periodontitis (DP) is recognized as an inflammatory disease that can lead to teeth loss. Uncontrolled chronic low-grade inflammation-induced senescence impairs the stemness of human periodontal stem cells (hPDLSCs). Sirtuin 3 (SIRT3), an NAD+-dependent deacetylase, is pivotal in various biological processes and is closely linked to aging and aging-related diseases. This study aims to explore the mechanism of SIRT3-related senescence and osteogenic differentiation of hPDLSCs under DP and explored the novelty therapeutic targets. Our study revealed that SIRT3 expression was markedly inhibited in periodontal ligament stem cells (PDLSCs) stimulated by high glucose and lipopolysaccharide. Both in vitro and in vivo, reduced SIRT3 expression accelerated cell senescence and impaired osteogenic differentiation of hPDLSCs. We demonstrated that SIRT3 binds to and deacetylates leucine-rich pentatricopeptide repeat-containing protein (LRPPRC), thereby modulating senescence. Additionally, we found that LRPPRC regulates senescence by modulating oxidative phosphorylation and oxidative stress. The activation of SIRT3 by honokiol significantly delayed senescence and promoted alveolar bone regeneration in mice after DP. Our findings indicate that the activation of SIRT3 negatively regulates hPDLSCs senescence by deacetylating LRPPRC, suggesting SIRT3 as a promising therapeutic target for DP.

Honokiol protects against diabetic retinal microvascular injury via sirtuin 3-mediated mitochondrial fusion

Introduction

Mitochondrial dysfunction and oxidative stress play important roles in diabetic retinal vascular injuries. Honokiol (HKL) is a small-molecule polyphenol that exhibits antioxidant effects and has a beneficial effect in diabetes. This study aimed to explore the potential ability of HKL to ameliorate vascular injury in diabetic retinopathy (DR) and its possible mechanisms of action.

Methods

The effect of HKL was evaluated in vascular injury in an in vivo type 2 diabetic (db/db) mouse model. In vitro, retinal microvascular endothelial cells were treated with high glucose (HG) to simulate the pathological diabetic environment. Cell viability, expression of apoptosis-related proteins, cellular reactive oxygen species, mitochondrial membrane potential, and morphological changes in the mitochondria were examined.

Results

The diabetic mice exhibited severe retinal vascular damage, including vascular leakage in vivo and capillary endothelial cell apoptosis in vitro. HKL reversed the retinal vascular leakage in the diabetic mice. In vitro, HKL improved retinal capillary endothelial cell viability, decreased apoptosis, and reversed the HG-induced increased cellular oxidative stress and mitochondrial fragmentation. The sirtuin 3 (SIRT3) inhibitor 3-TYP blocked all the in vivo and in vitro protective effects of HKL against diabetic retinal vascular leakage and capillary endothelium and eliminated the decrease in oxidative stress levels and reduction of mitochondrial fragmentation.

Discussion

In conclusion, these findings suggest that HKL inhibits vascular injury in DR, which was likely achieved through SIRT3-mediated mitochondrial fusion. This study provides a potential new strategy for the treatment of DR.

Therapeutic effects of natural compounds against diabetic complications via targeted modulation of ferroptosis

Diabetes mellitus, a chronic metabolic disorder, can result in serious tissue and organ damage due to long-term metabolic dysfunction, leading to various complications. Therefore, exploring the pathogenesis of diabetic complications and developing effective prevention and treatment drugs is crucial. The role of ferroptosis in diabetic complications has emerged as a significant area of research in recent years. Ferroptosis, a recently discovered form of regulated cell death closely linked to iron metabolism imbalance and lipid peroxidation, has garnered increasing attention in studies exploring the potential role of natural products in its regulation. This review provides an overview of the mechanisms underlying ferroptosis, outlines detection methods, and synthesizes information from natural product databases. It also summarizes current research on how natural products may regulate ferroptosis in diabetic complications. Studies have shown that these products can modulate the ferroptosis process by influencing iron ion balance and combating oxidative stress. This highlights the potential of natural products in treating diabetic complications by regulating ferroptosis, offering a new strategy for managing such complications.

The therapeutic potential of traditional Chinese medicine in depression: focused on the modulation of neuroplasticity

Depression, a mood disorder characterized by a persistent low mood and lack of enjoyment, is considered the leading cause of non-fatal health losses worldwide. Neuroplasticity refers to the brain's ability to adapt to external or internal stimuli, resulting in functional and structural changes. This process plays a crucial role in the development of depression. Traditional Chinese Medicine (TCM) shows significant potential as a complementary and alternative therapy for neurological diseases, including depression. However, there has been no systematic summary of the role of neuroplasticity in the pathological development of depression and TCM Interventions currently. This review systematically summarized recent literature on changes in neuroplasticity in depression and analyzed the regulatory mechanisms of active metabolites in TCM and TCM formulas on neuroplasticity in antidepressant treatment. Additionally, this review discussed the limitations of current research and the application prospects of TCM in regulating neuroplasticity in antidepressant research.

Diabetic peripheral neuropathy based on Schwann cell injury: mechanisms of cell death regulation and therapeutic perspectives

Diabetic peripheral neuropathy (DPN) is a complication of diabetes mellitus that lacks specific treatment, its high prevalence and disabling neuropathic pain greatly affects patients' physical and mental health. Schwann cells (SCs) are the major glial cells of the peripheral nervous system, which play an important role in various inflammatory and metabolic neuropathies by providing nutritional support, wrapping axons and promoting repair and regeneration. Increasingly, high glucose (HG) has been found to promote the progression of DPN pathogenesis by targeting SCs death regulation, thus revealing the specific molecular process of programmed cell death (PCD) in which SCs are disrupted is an important link to gain insight into the pathogenesis of DPN. This paper is the first to review the recent progress of HG studies on apoptosis, autophagy, pyroptosis, ferroptosis and necroptosis pathways in SCs, and points out the crosstalk between various PCDs and the related therapeutic perspectives, with the aim of providing new perspectives for a deeper understanding of the mechanisms of DPN and the exploration of effective therapeutic targets.

Recent advances of honokiol：pharmacological activities, manmade derivatives and structure-activity relationship

Honokiol (HNK) is a typical natural biphenyl polyphenol compound. It has been proven to have a wide range of biological activities, including pharmacological effects such as anti-cancer, anti-inflammatory, neuroprotective, and antimicrobial. However, due to the poor stability, water solubility, and bioavailability of HNK, HNK has not been used in clinical treatment. This article reviews the latest research on the pharmacological activity of HNK and summarizes the HNK derivatives designed and improved by several researchers. Reviewing these contents could promote the research process of HNK and guide the design of better HNK derivatives for clinical application in the future.

SIRT3: A potential therapeutic target for liver fibrosis

Sirtuin3 (SIRT3) is a nicotinamide adenine dinucleotide (NAD+)-dependent protein deacetylase located in the mitochondria, which mainly regulates the acetylation of mitochondrial proteins. In addition, SIRT3 is involved in critical biological processes, including oxidative stress, inflammation, DNA damage, and apoptosis, all of which are closely related to the progression of liver disease. Liver fibrosis characterized by the deposition of extracellular matrix is a result of long termed or repeated liver damage, frequently accompanied by damaged hepatocytes, the recruitment of inflammatory cells, and the activation of hepatic stellate cells. Based on the functions and pharmacology of SIRT3, we will review its roles in liver fibrosis from three aspects: First, the main functions and pharmacological effects of SIRT3 were investigated based on its structure. Second, the roles of SIRT3 in major cells in the liver were summarized to reveal its mechanism in developing liver fibrosis. Last, drugs that regulate SIRT3 to prevent and treat liver fibrosis were discussed. In conclusion, exploring the pharmacological effects of SIRT3, especially in the liver, may be a potential strategy for treating liver fibrosis.

Roles of Sirt1 and its modulators in diabetic microangiopathy: A review

Diabetic vascular complications include diabetic macroangiopathy and diabetic microangiopathy. Diabetic microangiopathy is characterised by impaired microvascular endothelial function, basement membrane thickening, and microthrombosis, which may promote renal, ocular, cardiac, and peripheral system damage in diabetic patients. Therefore, new preventive and therapeutic strategies are urgently required. Sirt1, a member of the nicotinamide adenine dinucleotide-dependent histone deacetylase class III family, regulates different organ growth and development, oxidative stress, mitochondrial function, metabolism, inflammation, and aging. Sirt1 is downregulated in vascular injury and microangiopathy. Moreover, its expression and distribution in different organs correlate with age and play critical regulatory roles in oxidative stress and inflammation. This review introduces the background of diabetic microangiopathy and the main functions of Sirt1. Then, the relationship between Sirt1 and different diabetic microangiopathies and the regulatory roles mediated by different cells are described. Finally, we summarize the modulators that target Sirt1 to ameliorate diabetic microangiopathy as an essential preventive and therapeutic measure for diabetic microangiopathy. In conclusion, targeting Sirt1 may be a new therapeutic strategy for diabetic microangiopathy.