Nicotinate-curcumin improves NASH by inhibiting the AKR1B10/ACCα-mediated triglyceride synthesis.

BACKGROUND: Nonalcoholic steatohepatitis (NASH) is a prevalent chronic liver condition. However, the potential therapeutic benefits and underlying mechanism of nicotinate-curcumin (NC) in the treatment of NASH remain uncertain. METHODS: A rat model of NASH induced by a high-fat and high-fructose diet was treated with nicotinate-curcumin (NC, 20, 40 mg·kg- 1), curcumin (Cur, 40 mg·kg- 1) and metformin (Met, 50 mg·kg- 1) for a duration of 4 weeks. The interaction between NASH, Cur and Aldo-Keto reductase family 1 member B10 (AKR1B10) was filter and analyzed using network pharmacology. The interaction of Cur, NC and AKR1B10 was analyzed using molecular docking techniques, and the binding energy of Cur and NC with AKR1B10 was compared. HepG2 cells were induced by Ox-LDL (25 µg·ml- 1, 24 h) in high glucose medium. NC (20µM, 40µM), Cur (40µM) Met (150µM) and epalrestat (Epa, 75µM) were administered individually. The activities of ALT, AST, ALP and the levels of LDL, HDL, TG, TC and FFA in serum were quantified using a chemiluminescence assay. Based on the changes in the above indicators, score according to NAS standards. The activities of Acetyl-CoA and Malonyl-CoA were measured using an ELISA assay. And the expression and cellular localization of AKR1B10 and Acetyl-CoA carboxylase (ACCα) in HepG2 cells were detected by Western blotting and immunofluorescence. RESULTS: The results of the animal experiments demonstrated that NASH rat model induced by a high-fat and high-fructose diet exhibited pronounced dysfunction in liver function and lipid metabolism. Additionally, there was a significant increase in serum levels of FFA and TG, as well as elevated expression of AKR1B10 and ACCα, and heightened activity of Acetyl-CoA and Malonyl-CoA in liver tissue. The administration of NC showed to enhance liver function in rats with NASH, leading to reductions in ALT, AST and ALP levels, and decrease in blood lipid and significant inhibition of FFA and TG synthesis in the liver. Network pharmacological analysis identified AKR1B10 and ACCα as potential targets for NASH treatment. Molecular docking studies revealed that both Cur and NC are capable of binding to AKR1B10, with NC exhibiting a stronger binding energy to AKR1B10. Western blot analysis demonstrated an upregulation in the expression of AKR1B10 and ACCα in the liver tissue of NASH rats, accompanied by elevated Acetyl-CoA and Malonyl-CoA activity, and increased levels of FFA and TG. The results of the HepG2 cell experiments induced by Ox-LDL suggest that NC significantly inhibited the expression and co-localization of AKR1B10 and ACCα, while also reduced levels of TC and LDL-C and increased level of HDL-C. These effects are accompanied by a decrease in the activities of ACCα and Malonyl-CoA, and levels of FFA and TG. Furthermore, the impact of NC appears to be more pronounced compared to Cur. CONCLUSION: NC could effectively treat NASH and improve liver function and lipid metabolism disorder. The mechanism of NC is related to the inhibition of AKR1B10/ACCα pathway and FFA/TG synthesis of liver.

The molecular mechanisms of chemotherapeutic resistance in tumors (Review).

Chemotherapy remains a prevalent treatment for a wide range of tumors; however, the majority of patients undergoing conventional chemotherapy experience varying levels of chemoresistance, ultimately leading to suboptimal outcomes. The present article provided an in­depth review of chemotherapy resistance in tumors, emphasizing the underlying factors contributing to this resistance in tumor cells. It also explored recent advancements in the identification of key molecules and molecular mechanisms within the primary chemoresistant pathways.

A novel model of cholesterol efflux from lipid-loaded cells.

Cholesterol efflux from lipid-loaded cells is a key athero-protective event that counteracts cholesterol uptake. The imbalance between cholesterol efflux and uptake determines the prevention or development of atherosclerosis. Many proteins and factors participate in the cholesterol efflux event. However, there are currently no systematic models of reverse cholesterol transport (RCT) that include most RCT-related factors and events. On the basis of recent research findings from other and our laboratories, we propose a novel model of one center and four systems with coupling transportation and networking regulation. This model represents a common way of cholesterol efflux; however, the systems in the model consist of different proteins/factors in different cells. In this review, we evaluate the novel model in vascular smooth muscle cells (VSMCs) and macrophages, which are the most important original cells of foam cells. This novel model consists of 1) a caveolae transport center, 2) an intracellular trafficking system of the caveolin-1 complex, 3) a transmembrane transport system of the ABC-A1 complex, 4) a transmembrane transport system of the SR-B1 complex, and 5) an extracelluar trafficking system of HDL/Apo-A1. In brief, the caveolin-1 system transports cholesterol from intracellular compartments to caveolae. Subsequently, both ABC-A1 and SR-B1 complex systems transfer cholesterol from caveolae to extracellular HDL/Apo-A1. The four systems are linked by a regulatory network. This model provides a simple and concise way to understand the dynamic process of atherosclerosis.

[Screening of the drug resistance-associated gene in HepG2 cell line transfected with aldose reductase like gene-1 (ARL-1)].

BACKGROUND & OBJECTIVE: Aldose reductase like gene-1 overexpresses in hepatocellular carcinomas; it might be the drug resistance- associated gene to anti-tumor drugs containing carbonyl groups on hepatocellular carcinomas. This study was designed to establish human hepatocellular carcinoma cell line (HepG2) transfected with aldose reductase like gene-1 (ARL-1), then to observe the changes of drug resistance to anti-tumor drugs with carbonyl group and screen the drug resistance-associated genes through cDNA chip. METHODS: PBK/ARL-1 plasmid was transfected to HepG2 cells by liposome to establish HepG2 monoclonal cells with high expression of ARL-1. The HepG2 cells with high expression of ARL-1 were determined by reverse transcription-polymerase chain reaction (RT-PCR),flow cytometric analysis (FCA), and immunohistochemical staining. MTT assay and cell apoptosis analysis were performed to determine the drug resistance ability of the cells to Adriamycin (ADM) and mytomycin (MMC), which contain carbonyl group. 5-fluorouracil (5-FU) that has no carbonyl group was used as control. Then two kinds of cDNA probes were made from HepG2 cells and ARL-HepG2 cells and labeled with Cy3 and Cy5 dyes. The probes were hybridized to the human liver cDNA chip and differentially expressed genes from the two cells were screened. The genes could be involved in drug resistance were confirmed by RT-PCR and Western blot. RESULTS: Compared with HepG2 cells, HepG2 cells transfected with ARL-1 gene have an increase in expression of ARL-1. Drug resistance ability of HepG2 cells transfected with ARL-1 gene to ADM and MMC increased 2.6 and 3.47 folds, respectively (t=6.39, P< 0.05 in ADM group; t=30.06, P< 0.01 in MMC group). Drug resistance to 5-FU had no statistical difference between them (t=0.684,P >0.05 in 5-FU group). 15 genes down-regulated and 9 genes up-regulated after transfected with ARL-1 gene were found by cDNA chip scanned. Some differentially displayed genes such as ubiquitin and MDR confirmed by RT-PCR and Western blot were consistent to the results of cDNA chip. CONCLUSION: The HepG2 cells with high expression of ARL-1 have more drug resistance to anti-tumor drugs with carbonyl group. Up-regulated MDR expression and down-regulated ubiquitin expression may contribute to the drug resistance of HepG2 cells.