The mechanisms of natural products for eye disorders by targeting mitochondrial dysfunction.

The human eye is susceptible to various disorders that affect its structure or function, including glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy (DR). Mitochondrial dysfunction has been identified as a critical factor in the pathogenesis and progression of eye disorders, making it a potential therapeutic target in the clinic. Natural products have been used in traditional medicine for centuries and continue to play a significant role in modern drug development and clinical therapeutics. Recently, there has been a surge in research exploring the efficacy of natural products in treating eye disorders and their underlying physiological mechanisms. This review aims to discuss the involvement of mitochondrial dysfunction in eye disorders and summarize the recent advances in the application of natural products targeting mitochondria. In addition, we describe the future perspective and challenges in the development of mitochondria-targeting natural products.

Targeted inhibition of branched-chain amino acid metabolism drives apoptosis of glioblastoma by facilitating ubiquitin degradation of Mfn2 and oxidative stress.

Glioblastoma is one of the most challenging malignancies with high aggressiveness and invasiveness and its development and progression of glioblastoma highly depends on branched-chain amino acid (BCAA) metabolism. The study aimed to investigate effects of inhibition of BCAA metabolism with cytosolic branched-chain amino acid transaminase (BCATc) Inhibitor 2 on glioblastoma, elucidate its underlying mechanisms, and explore therapeutic potential of targeting BCAA metabolism. The expression of BCATc was upregulated in glioblastoma and BCATc Inhibitor 2 precipitated apoptosis both in vivo and in vitro with the activation of Bax/Bcl2/Caspase-3/Caspase-9 axis. In addition, BCATc Inhibitor 2 promoted K63-linkage ubiquitination of mitofusin 2 (Mfn2), which subsequently caused lysosomal degradation of Mfn2, and then oxidative stress, mitochondrial fission and loss of mitochondrial membrane potential. Furthermore, BCATc Inhibitor 2 treatment resulted in metabolic reprogramming, and significant inhibition of expression of ATP5A, UQCRC2, SDHB and COX II, indicative of suppressed oxidative phosphorylation. Moreover, Mfn2 overexpression or scavenging mitochondria-originated reactive oxygen species (ROS) with mito-TEMPO ameliorated BCATc Inhibitor 2-induced oxidative stress, mitochondrial membrane potential disruption and mitochondrial fission, and abrogated the inhibitory effect of BCATc Inhibitor 2 on glioblastoma cells through PI3K/AKT/mTOR signaling. All of these findings indicate suppression of BCAA metabolism promotes glioblastoma cell apoptosis via disruption of Mfn2-mediated mitochondrial dynamics and inhibition of PI3K/AKT/mTOR pathway, and suggest that BCAA metabolism can be targeted for developing therapeutic agents to treat glioblastoma.

Natural Products in Liver Fibrosis Management: A Five-year Review.

Liver fibrosis, characterized by the overproduction of extracellular matrix proteins within liver tissue, poses a rising global health concern. However, no approved antifibrotic drugs are currently available, highlighting the critical need for understanding the molecular mechanisms of liver fibrosis. This knowledge could not only aid in developing therapies but also enable early intervention, enhance disease prediction, and improve our understanding of the interaction between various underlying conditions and the liver. Notably, natural products used in traditional medicine systems worldwide and demonstrating diverse biochemical and pharmacological activities are increasingly recognized for their potential in treating liver fibrosis. This review aims to comprehensively understand liver fibrosis, emphasizing the molecular mechanisms and advancements in exploring natural products' antifibrotic potential over the past five years. It also acknowledges the challenges in their development and seeks to underscore their potency in enhancing patient prognosis and reducing the global burden of liver disease.

Metformin protects against retinal ischemia/reperfusion injury through AMPK-mediated mitochondrial fusion.

Retinal ischemia/reperfusion (I/R) injury is a common pathological process responsible for cellular damage in glaucoma, diabetic retinopathy and hypertensive retinopathy. Metformin is a biguanide drug that exerts strong effects on multiple diseases. This study aims to evaluate the protective effect of metformin against retinal I/R injury and its underlying mechanism. I/R induced reduction in retina thickness and cell number in ganglion cell layer, and metformin alleviated I/R-induced retinal injury. Both retinal I/R and simulated ischemia/reperfusion (SIR) in R28 cells down-regulated expression of mitochondrial fusion protein Mfn2 and OPA1, which led to mitochondrial fission. Metformin also alleviated damage in R28 cells, and reversed the alteration in Mfn2 and OPA1, mitochondrial fission and mitochondrial membrane potential (MMP) disruption-induced by I/R or SIR as well. Intriguingly, inhibition of AMPK by compound C or siRNA prevented metformin-mediated up-regulation of Mfn2 and OPA1. Compound C and knockdown of Mfn2 or OPA1 dramatically alleviated the protective effect of metformin against intracellular ROS generation, MMP disruption, mitochondrial fission and loss of RGCs in ganglion cell layer induced by SIR or I/R. Moreover, scavenging mitochondrial ROS (mito-ROS) by mito-TEMPO exerted the similar protection against I/R-induced retinal injury or SIR-induced damage in R28 cells as metformin. Our data show for the first time that metformin protects against retinal I/R injury through AMPK-mediated mitochondrial fusion and the decreased mito-ROS generation. These findings might also repurpose metformin as a therapeutic agent for retinal I/R injury.

BCATc inhibitor 2 ameliorated mitochondrial dysfunction and apoptosis in oleic acid-induced non-alcoholic fatty liver disease model.

Nonalcoholic fatty liver disease (NAFLD) is a prevalent hepatic disease in the world. Disorders of branched chain amino acid (BCAA) metabolism is involved in various diseases. In this study, we aim to explore the role of BCAA metabolism in the development of NAFLD and the protective effect of BCATc Inhibitor 2, an inhibitor of cytosolic branched chain amino acid transaminase, against NAFLD as well as its underlying mechanism. It was found that oleic acid induced lipid accumulation and apoptosis in HepG2 and LO2 cells. Supplementation of BCAAs further aggravated oleic acid-induced lipid accumulation and apoptosis. In contrast, treatment of BCATc Inhibitor 2 ameliorated oleic acid-induced lipid accumulation and apoptosis. Molecularly, supplementation of BCAAs or treatment of BCATc Inhibitor 2 up-regulated or down-regulated the expression of SREBP1 and lipogenesis-related genes without affecting lipolysis-related genes. BCATc Inhibitor 2 maintained mitochondrial function by ameliorating oleic acid-induced mitochondrial ROS generation and mitochondrial membrane potential disruption. In addition, BCATc Inhibitor 2 treatment alleviated oleic acid-induced activation of JNK and AKT signaling pathway and Bcl2/Bax/Caspase axis. In conclusion, our results indicate BCAA metabolism is involved in NAFLD and BCATc Inhibitor 2 protects against oleic acid-induced lipid accumulation and apoptosis. These findings suggest that BCATc Inhibitor 2 is a promising candidate drug for the treatment of NAFLD.

Association of the GLI gene with ventricular septal defect after the susceptibility gene being narrowed to 3.56 cM in 12q13.

BACKGROUND: Our previous research has suggested that genes around D12S1056 in 12q13 may confer susceptibility to ventricular septal defect (VSD) in humans. The present study was to define the chromosome region assignment by transmission disequilibrium test (TDT), and to identify the important candidate gene by family-based association study and haplotype analysis. METHODS: Surrounding D12S1056, ten microsatellite markers including D12S329, D12S305, D12S1662, D12S1056, D12S1293, D12S334, D12S102, D12S83, D12S1655 and D12S1691 were chosen, and TDT was performed in 62 nuclear family trios each consisting of an affected child and two healty parents. Subsequently, the GLI gene, a positional candidate gene that maps to the target region, was selected for further analysis. Three single nucleotide polymorphisms (SNPs), G11888C, G11388A, and G11625T, were selected for family-based association study and haplotype analysis. RESULTS: VSD was significantly associated with all selected markers except D12S1691 [72.2 centi morgen (cM)] and D12S1700 (75.76 cM). VSD was also significantly associated with G11888C (chi(2) = 5.918, P = 0.015), G11388A (chi(2) = 8.067, P = 0.005), and G11625T (chi(2) = 11.842, P = 0.001). Haplotype analysis showed a strong linkage disequilibrium between G11888C and G11388A (D' = 0.999), but in significant (chi(2) = 1.035, df = 2, P > 0.05). CONCLUSIONS: The susceptibility gene of VSD was mapped to 3.56 cM in 12q13 by TDT, and the GLI gene, an important candidate in the target region, was associated with VSD.

[Analysis on genetic polymorphism of 14 short tandem repeat loci on chromosome 7p14-15 and 12q13 in Chinese north Hans].

OBJECTIVE: To analyze the genetic polymorphism of 6 short tandem repeat (STR) loci on chromosome 7p14-15 and 8 STR loci on chromosome 12q13 in Chinese north Hans. METHODS: Fluorescence-labeling polymerase chain reaction and capillary electrophoresis were used to analyze the genetic polymorphism of 100 randomly selected individuals from Chinese north Han nationality at 6 STR loci (D7S1808, D7S2250, D7S2251, D7S683, D7S656 and D7S528) on chromosome 7p14-15 and 8 STR loci(D12S1056, D12S1293, D12S83, D12S1655, D12S1662, D12S334, D12S137 and D12S102) on chromosome 12q13. RESULTS: In the Chinese north Han population, 7 alleles and 24 genotypes, 8 alleles and 27 genotypes, 7 alleles and 22 genotypes, 4 alleles and 10 genotypes, 6 alleles and 17 genotypes, 5 alleles and 13 genotypes were observed at D7S1808, D7S2250, D7S2251, D7S683, D7S656 and D7S528. The heterozygosities at the above 6 STR loci were 86%, 88%, 83%, 79%, 85% and 80%, respectively. Five alleles and 15 genotypes, 5 alleles and 15 genotypes, 8 alleles and 29 genotypes, 6 alleles and 17 genotypes, 6 alleles and 17 genotypes, 6 alleles and 19 genotypes, 5 alleles and 13 genotypes, 7 alleles and 24 genotypes were observed at D12S1056, D12S1293, D12S83, D12S1655, D12S1662, D12S334, D12S137 and D12S102. The heterozygosities at the above 8 STR loci were 86%, 84%, 87%, 82%, 84%, 85%, 81% and 89%, respectively. CONCLUSION: The distributions of allele frequencies of 6 STR loci on chromosome 7p14-15 and of 8 STR loci on chromosome 12q13 were consistent with the Hardy-Weinberg equilibrium. The highly genetic polymorphism was observed in Chinese north Han population.