OGD/R-induced ferroptosis and pyroptosis in retinal pigment epithelium cells: Role of PLD1 and PLD2 modulation.

This study investigated the role of phospholipase D (PLD) in retinal ischemia-reperfusion (I/R) injury using an oxygen-glucose deprivation/reperfusion (OGD/R) model commonly used in retinal I/R injury research. To create an in vitro cellular I/R model, pharmacological inhibitors and small interfering RNA (siRNA) were used to target PLD1 and PLD2 in retinal pigment epithelial (RPE) cells. Treatment with PLD inhibitors and siRNA reduced reactive oxygen species (ROS) and malondialdehyde (MDA) induced by OGD/R in RPE cells and increased the levels of superoxide dismutase (SOD) and glutathione (GSH), indicating a reduction in oxidative damage and improvement in the antioxidant system. Next, we showed that inhibiting PLD1 or PLD2 reduced intracellular iron levels and lipid peroxidation, which are critical factors in ferroptosis. Additionally, PLD1 and PLD2 modulated the expression of proteins involved in the regulation of ferroptosis, including GPX4, SLC7A11, FTH1, and ACSL4. We also investigated the roles of PLD1 and PLD2 in preventing pyroptosis, another form of programmed cell death associated with inflammation. Our study found that OGD/R significantly increased the production of pro-inflammatory cytokines and activated caspase-1, NLRP3, ASC, cleaved-caspase 1 (C-caspase-1), and GSDMD-N in RPE cells, indicating pyroptosis induction. However, PLD1 and PLD2 inhibition or knockdown significantly inhibited the production of pro-inflammatory cytokines and activation of the NLRP3 inflammasome, Taken together, our findings support the hypothesis that the PLD signaling pathway plays a key role in OGD/R-induced ferroptosis and pyroptosis induction and may be a potential therapeutic target for preventing or treating retinal dysfunction and degeneration.

Adiposity Reduction by Cucumis melo var. gaettongchamoe Extract in High-Fat Diet-Induced Obese Mice.

This study investigated the anti-obesity effects of Cucumis melo var. gaettongchamoe (CG) in mice fed a high-fat diet (HFD). The mice received CG water extract (CGWE) treatment for 8 weeks, and changes in body weight and serum lipid levels were analyzed. The HFD + vehicle group showed a significant increase in body weight compared to the control group, while the HFD + CGWE and HFD + positive (orlistat) groups exhibited reduced body weight. Lipid profile analysis revealed lower levels of total cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein cholesterol in the HFD + CGWE group compared to the HFD + vehicle group. The HFD + vehicle group had increased abdominal fat weight and fat content, whereas both HFD + CGWE groups showed significant reductions in abdominal fat content and adipocyte size. Additionally, CGWE administration downregulated mRNA expression of key proteins involved in neutral lipid metabolism. CGWE also promoted hepatic lipolysis, reducing lipid droplet accumulation in hepatic tissue and altering neutral lipid metabolism protein expression. Furthermore, CGWE treatment reduced inflammatory mediators and suppressed the activation of the mitogen-activated protein kinase pathway in hepatic tissue. In conclusion, CGWE shows promise as a therapeutic intervention for obesity and associated metabolic dysregulation, including alterations in body weight, serum lipid profiles, adipose tissue accumulation, hepatic lipolysis, and the inflammatory response. CGWE may serve as a potential natural anti-obesity agent.

Edible Vitalmelon Fruit Extract Inhibits Adipogenesis and Ameliorates High-Fat Diet-Induced Obesity.

Conventional breeding of wild (Cucumis melo var. makuwa Makino (CM)) and cultivated (Cucumis melo var. reticulatus (CR)) melons is aimed at improving their biological traits. Here, we prepared a nontoxic, bioactive extract of vitalmelon (F1 hybrid) and evaluated its antiadipogenic and antiobesity effects in fully differentiated 3T3-L1 adipocytes and high-fat diet- (HFD-) induced obese C57BL/6 mice. In fully differentiated 3T3-L1 adipocytes, the vitalmelon extract reduced the DMI- (dexamethasone, 3-isobutyl-1-methylxanthine, and insulin-) induced increases in lipid droplet number and intracellular glucose and triglyceride levels. In addition, the extract inhibited 3T3-L1 preadipocyte differentiation by downregulating PPAR-γ and target genes LPL, CD36, HMGCR, and L-FABP. To investigate the inhibitory effects of the vitalmelon extract on lipid metabolism, we measured serum lipid, hormone, and cytokine concentrations; lipolytic activity; lipid accumulation; and adipogenesis in HFD-fed mice treated with the extract. The HFD+vitalmelon-fed mice showed lower blood cholesterol, free fatty acid, sugar, leptin, and insulin concentrations but higher blood adiponectin concentrations than the HFD-fed mice. Moreover, the HFD+vitalmelon-fed mice showed lower abdominal fat levels, smaller fat cells, lower weight, and fewer lipid droplets in the liver tissue than the HFD-fed mice. Therefore, in HFD-fed mice, vitalmelon regulated lipid metabolism through PPAR-γ, highlighting its potential as a promising antiobesity functional food.

Comparative study of the photo­protective and anti­melanogenic properties of gomisin D, J and O.

Skin cancer is the most common human malignancy worldwide and solar ultraviolet (UV) radiation is known to serve an important role in its pathogenesis. Natural candidate compounds with antioxidant, photoprotective and anti­melanogenic effects were investigated against the background of skin photoprotective and anti­melanogenic properties. Gomisin D, J and O are dibenzocyclooctadiene lignans present in Kadsura medicinal plants and possess several pharmacological activities. In this study, the functions and mechanisms underlying the effects of gomisin D, J and O in UVA­and UVB­irradiated keratinocytes and α­melanocyte stimulating hormone (α­MSH)­stimulated melanocytes were explored. Following UVA and UVB irradiation, keratinocytes were treated with gomisin D, J and O, and keratinocyte viability, lactate dehydrogenase (LDH) release, intracellular reactive oxygen species (ROS) production and apoptosis were examined. The results demonstrated that gomisin D and J improved keratinocyte viability and reduced LDH release under UVA and UVB irradiation. Intracellular ROS production induced by UVA and UVB irradiation was suppressed by gomisin D and J. In addition, Annexin V and TUNEL staining analysis indicated that gomisin D and J have significant anti­apoptotic effects on UVA­and UVB­irradiated keratinocytes. After α­MSH stimulation, melanocytes were treated with gomisin D, J and O, and the changes in melanocyte viability, intracellular melanin content, intracellular tyrosinase activity, and mechanisms underlying these changes were examined. Gomisin D markedly inhibited the α­MSH­induced increase in intracellular melanin content and tyrosinase activity. Mechanistically, gomisin D reduced the protein and mRNA expression levels of microphthalmia­associated transcription factor (MITF), tyrosinase, tyrosinase­related protein (TRP)­1 and TRP­2 in α­MSH­stimulated melanocytes. In addition, gomisin D markedly downregulated α­MSH­induced phosphorylation of protein kinase A and cAMP response element binding protein, which are known to be present upstream of the MITF, tyrosinase, TRP­1 and TRP­2 genes. Overall, gomisin D has photoprotective and anti­melanogenic effects; these findings provide a basis for the production of potential brightening and photoprotective agents using natural compounds such as gomisin D.

A Comparative Study on Photo-Protective and Anti-Melanogenic Properties of Different Kadsura coccinea Extracts.

Kadsura coccinea (KC), a beneficial plant for human health, has been used for centuries in China, Thailand, and Korea in folk medicine and food. There is evidence supporting the biological effects of highly bioactive ingredients in KC such as lignans, triterpenoids, flavonoids, phenolic acids, steroids, and amino acids. In this study, we aimed to explore the effects, functions, and mechanisms of the extracts from KC root (KCR), stem (KCS), leaf (KCL), and fruit (KCF) in UVA and UVB-irradiated keratinocytes and α-melanocyte stimulating hormone (α-MSH)-stimulated melanocytes. First, the total polyphenol and flavonoid contents of KCR, KCS, KCL, and KCF and their radical scavenging activities were investigated. These parameters were found to be in the following order: KCL > KCR > KCS > KCF. UVA and UVB-irradiated keratinocytes were treated with KCR, KCS, KCL, and KCF, and keratinocyte viability, LDH release, intracellular ROS production, and apoptosis were examined. Our results demonstrated that KC extracts improved keratinocyte viability and reduced LDH release, intracellular ROS production, and apoptosis in the presence UVA and UVB irradiation. The overall photoprotective activity of the KC extracts was confirmed in the following order: KCL > KCR > KCS > KCF. Moreover, KC extracts significantly decreased the intracellular melanin content and tyrosinase activity in α-MSH-stimulated melanocytes. Mechanistically, KC extracts reduced the protein and mRNA expression levels of tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2) in α-MSH-stimulated melanocytes. In addition, these extracts markedly downregulated myophthalmosis-related transcription factor expression and cAMP-related binding protein phosphorylation, which is upstream of the regulation of Tyrosinase, TRP-1, and TRP-2. The overall anti-melanogenic activity of the KC extracts was established in the following order. KCL > KCR > KCS > KCF. Overall, the KC extracts exert photoprotective and anti-melanogenic effects, providing a basis for developing potential skin-whitening and photoprotective agents.