Linarin ameliorates dextran sulfate sodium-induced colitis in C57BL/6J mice via the improvement of intestinal barrier, suppression of inflammatory responses and modulation of gut microbiota.

Linarin is a natural flavonoid compound found in Chrysanthemum indicum, Mentha species and other plants with various biological activities. The study aimed to investigate the protective effect of linarin supplementation on dextran sulfate sodium (DSS)-induced colitis in C57BL/6J mice and its potential mechanisms. The results showed that doses of linarin at 25 and 50 mg kg-1 day-1 alleviated the DSS-induced histopathological damage, and improved the mucosal layer and intestinal barrier function. Importantly, Linarin significantly suppressed the levels of myeloperoxidase activity and pro-inflammatory cytokines (IL-6, TNF-α, IFN-γ and IL-1ß) in the colon, and enhanced the mRNA level of anti-inflammatory cytokine (IL-10). Moreover, 50 mg kg-1 day-1 linarin reversed the gut microbiota damaged by DSS, including Alistipes, Rikenella and Clostridia UCG-014_norank. Linarin also partly increased the relative abundance of short-chain fatty acids (SCFAs)-producing bacteria, including Lactobacillus, Roseburia, Parabacteroides and Blautia, and elevated the contents of SCFAs. Collectively, linarin attenuates DSS-induced colitis in mice, suggesting that linarin may be a promising nutritional strategy for reducing inflammatory bowel disease.

Diosgenin Protects Against Kidney Injury and Mitochondrial Apoptosis Induced by 3-MCPD Through the Regulation of ER Stress, Ca2+ Homeostasis, and Bcl2 Expression.

SCOPE: Diosgenin (DIO) is a natural steroid sapogenin presented in various plants. It exerts anti-oxidant, anti-inflammatory and anti-diabetic nephropathy properties. The present study evaluates the intervention effect of DIO on nephrotoxicity induced by food contaminant 3-chloro-1, 2-propanediol (3-MCPD) in vivo and in vitro. METHODS AND RESULTS: Treatment with DIO (15 mg kg-1 d-1 ) in Sprague-Dawley rats for 4-week relieves kidney injury induced by 3-MCPD (30 mg kg-1 d-1 ). In vitro, DIO (2, 6, and 8 µM) alleviates cell injury and apoptosis effectively in human embryonic kidney (HEK293) cells. DIO realizes its protective function via the regulation of endoplasmic reticulum (ER) stress and mitochondrial apoptosis pathway. Blockage of ER stress by 4-phenylbutyric acid (4-PBA), a specific ER stress antagonist, inhibits mitochondrial apoptosis, suggesting a connection between mitochondrial apoptosis and ER stress. Furthermore, the study demonstrates that the maintenance of Ca2+ homeostasis and Bcl2 expression, two main targets of ER stress, contributes to the protection role of DIO on mitochondrial-dependent apoptosis. In addition, DIO relieves the impairment of oxidative phosphorylation. CONCLUSION: This study demonstrates that DIO exerts protective effect against kidney injury, mitochondrial dysfunction, and apoptosis through the inhibition of ER stress and the further maintenance of Ca2+ homeostasis and Bcl2 expression.

Involvement of NADPH oxidase in patulin-induced oxidative damage and cytotoxicity in HEK293 cells.

Patulin (PAT) is a kind of mycotoxins that commonly found in decayed fruits and their products. Our previous studies have shown that PAT induced cell apoptosis and the overproduction of reactive oxygen species (ROS) in human embryonic kidney (HEK293) cells. The present study aimed to further investigate the functional role of NADPH oxidase, one of the main cellular sources of ROS, in PAT-induced apoptosis and oxidative damage in HEK293 cells. We demonstrated that the protein and mRNA expression levels of NADPH oxidase catalytic subunit NOX2 and regulatory subunit p47phox were up-regulated under PAT stress. Inhibiting of NADPH oxidase with the specific antagonist diphenyleneiodonium (DPI) suppressed cytotoxicity and apoptosis induced by PAT as evidenced by the increase of cell viability, the decrease of LDH release and the inhibition of caspase activities. Furthermore, DPI re-established mitochondrial membrane potential (MMP) and enhanced cellular ATP content. Importantly, DPI supplementation elevated endogenous GSH contents as well as the ratio of GSH/GSSG. Meanwhile, the antioxidant-enzyme activities of GPx, GR, CAT and SOD were significantly promoted. Collectively, our results suggested that NADPH oxidase played a critical role in PAT-induced nephrotoxicity, and inhibition of NADPH oxidase by DPI attenuated cell injury and apoptosis via regulation of oxidative damage.

Drp1-mediated mitochondrial fission induced autophagy attenuates cell apoptosis caused by 3-chlorpropane-1,2-diol in HEK293 cells.

3-chlorpropane-1,2-diol (3-MCPD) is a heat-induced food process contaminant that threatens human health. As the primary target organ, the morphological and functional impairment of kidney and the related mechanism such as apoptosis and mitochondrial dysfunction were observed. However, the precise molecular mechanism remains largely unclear. This study aimed to explore the important role of mitochondrial fission and autophagy in the 3-MCPD-caused apoptosis of human embryonic kidney 293 (HEK293) cells. The results showed that blockage of dynamin-related protein-1 (Drp1) by mitochondrial division inhibitor 1 (Mdivi-1, 15 µM) apparently restored 3-MCPD-induced mitochondrial dysfunction, accompanied by prevented the collapse of mitochondrial membrane potential and ATP depletion, and suppressed the occurrence of autophagy. Induction of autophagy occurred following 2.5-10 mM 3-MCPD treatment for 24 h via AMPK mediated mTOR signaling pathway. Meanwhile, enhancement of autophagy by pretreatment with rapamycin (1 nM) alleviated the loss of cell viability and apoptosis induced by 3-MCPD whereas suppression of autophagy by 3-methyladenine (1 mM) further accelerated apoptosis, which was modulated through the mitochondria-dependent apoptotic pathway. Taking together, this study provides novel insights into the 3-MCPD-induced apoptosis in HEK293 cells and reveals that autophagy has potential as an effective intervention strategy for the treatment of 3-MCPD-induced nephrotoxicity.

The renoprotective effect of diosgenin on aristolochic acid I-induced renal injury in rats: impact on apoptosis, mitochondrial dynamics and autophagy.

Aristolochic acid I (AA-I) remains a leading cause of aristolochic acid nephropathy (AAN), however few prevention and treatment strategies exist. In this work, the nephroprotective effect of diosgenin, a steroidal saponin distributed abundantly in several plants, on AA-I-induced renal injury and its underlying mechanism were investigated. Sprague-Dawley rats were intragastrically administered with 30 mg kg-1 d-1 diosgenin two hours before exposure to 10 mg kg-1 d-1 AA-I for consecutive four weeks, and the histological change, the renal and liver function, apoptosis, autophagy and the involved pathways were investigated. The results showed that diosgenin relieved AA-I-induced renal histological damage, including mild edematous disorder of renal tubular arrangement and widening of renal tubular lumen. No obvious changes in the hepatic tissue structure were observed in all treatment groups. Moreover, diosgenin up-regulated the expression of Bcl-2 and down-regulated Bax, and subsequently inhibited AIF expression and the cleaved form of Caspase-3, thereby alleviating apoptosis triggered by AA-I. Diosgenin also mitigated AA-I-induced renal mitochondrial dynamics disorder by increasing the expression of mitochondrial dynamics-related proteins including DRP1 and MFN2. Diosgenin inhibited AA-I-evoked autophagy via ULK1-mediated inhibition of the mTOR pathway. Overall, these results suggest that diosgenin has a protective effect against AA-I-induced renal damage and it may be a potential agent for preventing AA-I-induced AAN.

Protective effects of apigenin against 3-MCPD-induced renal injury in rat.

Apigenin (API) is a kind of important flavonoid present in temperate and tropical fruit and vegetables, especially the celery. It exerts anticancer, anti-bacterial, anti-viral, anti-inflammatory, anti-oxidation properties. In the present study, the mechanism of protective action of apigenin on 3-chloro-1, 2-propanediol (3-MCPD)-induced renal injury was investigated in rat. Sprague-Dawley (SD) rats were divided into five groups: control group (ultrapure water treated), CMC group (sodium carboxymethylcellulose treated), 3-MCPD treatment group (30 mg/kg body weight/day), 3-MCPD plus API co-treatment group (20, 40 mg/kg body weight/day). The results showed that API significantly reduced renal function markers, serum creatinine and urea nitrogen content. Besides, the renal tissue lesion in 3-MCPD treatment group was restored by API to some extent. We indicated that API exerted renoprotective effect by modulating oxidative phosphorylation especially up-regulated the expressions of ATP6 and ATP8, re-establishing mitochondrial membrane potential (MMP), relieving the increase of Bax/Bcl2 ratio, reducing cytochrome c release, thus inhibiting the activation of Caspase 9 and Caspase 3. In conclusion, apigenin possesses excellent protective effect against 3-MCPD-induced renal injury by modulating mitochondria dependent Caspase cascade pathway.

Glutathione Reduction of Patulin-Evoked Cytotoxicity in HEK293 Cells by the Prevention of Oxidative Damage and the Mitochondrial Apoptotic Pathway.

Patulin (PAT) is a mycotoxin frequently detected in moldy fruits and fruit products. This study investigated the protective role of glutathione (GSH), an antioxidant agent, against PAT-induced cytotoxicity and its potential mechanisms in HEK293 cells. The obtained results showed that the addition of GSH significantly increased cell viability and decreased apoptosis induced by PAT. Additionally, GSH decreased intracellular ROS and mitochondrial ROS overproduction, suppressed the decline of the mitochondrial membrane potential, and maintained cellular ATP contents. GSH prevented the impairment of mitochondrial oxidative-phosphorylation system and, especially, enhanced the mRNA and protein levels of electron-transport-chain complex III (UQCRC2) and complex V (ATP5, ATP6 and ATP8). Furthermore, GSH increased endogenous GSH contents; enhanced the antioxidant-enzyme activities of SOD, CAT, GR, and GPx; and modulated oxidative damage. These results suggest that GSH reduces PAT-induced cytotoxicity via inhibition of oxidative damage and the mitochondrial apoptotic pathway in HEK293 cells.