Effects of nicotine on microRNA-124 expression in bile duct ligation-induced liver fibrosis in rats

BACKGROUND

Nicotine, the main compound of smoking may exert its effects by changing the expression of microRNAs (miRNAs). This study was conducted to further investigate the molecular mechanisms of miRNA-dependent effects of nicotine in an animal model of liver fibrosis.

METHODS

The bile duct ligation (BDL) approach was used to create a model of liver fibrosis. Twenty-four male Wistar rats were used in the study. The effects of nicotine administration on miRNA-124 expression, as well as alpha-smooth muscle actin (liver fibrosis marker) and chemokine ligand 2 (an inflammatory chemokine), were investigated using RT-qPCR. In addition, the mRNA and protein expression of signal transducer and activator of transcription 3 (STAT-3; as a potential target for miRNA-124) were investigated by RT-qPCR and immunofluorescence, respectively. Liver enzyme activity levels were measured using a colorimetric assay. In addition, the effects of nicotine on the process of liver fibrosis were investigated with histological studies.

RESULTS

The development of liver fibrosis in BDL rats and nicotine administration led to a decrease in miRNA-124 expression. The decrease in the expression is accompanied by the increase in the expression of fibrotic and proinflammatory genes. Also, an increase in STAT-3 mRNA and protein expression was observed in the fibrotic rats that received nicotine. In addition, the significant increase in bilirubin and liver enzymes in fibrotic rats worsens with nicotine administration. The results of histological studies also confirm these results.

CONCLUSION

Considering that miRNA-124 is an anti-inflammatory miRNA, it can be concluded that the decrease in its expression due to nicotine exposure leads to an increase in inflammatory processes and subsequently to an increase in liver fibrosis.

Hepatoprotection of capsaicin in alcoholic and non-alcoholic fatty liver diseases

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are common causes of chronic liver disease that share the range of steatosis, steatohepatitis, fibrosis, cirrhosis, and finally, hepatocellular carcinoma. They are identified by the dysregulation of disease-specific signalling pathways and unique microRNAs. Capsaicin is an active ingredient of chilli pepper that acts as an agonist of transient receptor potential vanilloid subfamily 1. It seems that the protective role of capsaicin against NAFLD and ALD is linked to its anti-steatotic, antioxidant, anti-inflammatory, and anti-fibrotic effects. Capsaicin-induced inhibiting metabolic syndrome and gut dysbiosis and increasing bile acids production are also involved in its anti-NAFLD role. This review summarises the different molecular mechanisms underlying the protective role of capsaicin against NAFLD and ALD. More experimental studies are needed to clarify the effects of capsaicin on the expression of genes involved in hepatic lipid metabolism and hepatocytes apoptosis in NAFLD and ALD.

trans-Chalcone inhibits transforming growth factor-β1 and connective tissue growth factor-dependent collagen expression in the heart of high-fat diet-fed rats

Objective: Non-alcoholic fatty liver disease (NAFLD) is one of the main risk factors for cardiovascular mortality and morbidity. This study, for the first time, explored the effects of trans-chalcone on cardiac expressions of myocardial fibrosis-related genes, including transforming growth factor -β1 (TGF-β1), connective tissue growth factor (CTGF/CCN2), and collagen type I.Materials and methods: Twenty-eight rats were randomly divided into four groups: control, received 10% tween 80; chalcone, received trans-chalcone; HFD, received high-fat diet (HFD) and 10% tween 80; HFD + chalcone, received HFD and trans-chalcone, by once-daily gavage for 6 weeks. Finally, cardiac expression levels of TGF-β1, CTGF, and collagen type I were determined.Results: HFD feeding increased mRNA levels of collagen type I, TGF-β1, and CTGF in the heart of rats. However, trans-chalcone inhibited HFD-induced changes.Conclusions: trans-Chalcone can act as a cardioprotective compound by inhibiting TGF-β1 and CTGF-dependent stimulation of collagen type I synthesis in the heart of HFD-fed rats.

Effect of ghrelin on hypoxia-related cardiac angiogenesis: involvement of miR-210 signalling pathway

OBJECTIVE

Hypoxia is the main stimulus for angiogenesis. Hypoxia-inducible factor (HIF)-1α, vascular endothelial growth factor (VEGF), and miR-210 are involved in the hypoxia-induced angiogenesis. This study examined the effects of hypoxia and/or ghrelin on miR-210, HIF-1α, and VEGF levels in the heart of rats.

METHODS

Wistar rats were randomly divided into 4 groups (n = 6): control; ghrelin, received daily intraperitoneal injections of ghrelin; hypoxia, was exposed to hypoxic condition; hypoxia + ghrelin, was exposed to hypoxic condition and received intraperitoneal injections of ghrelin, for 2 weeks. Myocardial angiogenesis, the expression level of miR-210, and protein levels of HIF-1α and VEGF were assayed in the heart samples.

RESULTS

Hypoxia increased myocardial angiogenesis and cardiac levels of miR-210, HIF-1α, and VEGF. However, ghrelin inhibited these hypoxia-induced changes. Interestingly, ghrelin had no significant effect on miR-210, HIF-1α, and VEGF levels in normoxic condition.

CONCLUSION

Ghrelin may be useful as an anti-angiogenic factor.

Protective Role of Trans-chalcone against the Progression from Simple Steatosis to Non-alcoholic Steatohepatitis: Regulation of miR-122, 21, 34a, and 451

Purpose: Non-alcoholic steatohepatitis (NASH) is an inflammatory disorder and an aggressive form of fatty liver disease. Certain microRNAs, including miR-122, 21, 34a, and 451, are involved in the transition from steatosis to NASH. This study examined how trans-chalcone (the core of chalcone derivatives) affects NAFLD progression by regulating miRNAs.

Methods: Male rats were divided into three groups (n = 7/group) as follows: control, rats were gavaged with 10% tween 80 (for two weeks); NASH, rats were gavaged with a high-fat liquid diet (HFD; for six weeks) and 10% tween 80 (for two weeks); NASH + Chal, rats were gavaged with the HFD (for six weeks) and trans-chalcone (for two weeks). Hepatic expression levels of miR-122, 21, 34a, and 451 were determined.

Results: trans-Chalcone reversed histological abnormalities, reduced liver injury markers, and attenuated insulin resistance in HFD-fed rats. In the liver, HFD-induced NASH increased the expression level of miR-34a and decreased expression levels of miR-122, 21, and 451. However, trans-chalcone inhibited HFD-induced changes in expression levels of these miRNAs.

Conclusion: trans-Chalcone could inhibit the transition from steatosis to NASH through the modulation of miR-122, 21, 34a, and 451 expression levels in the liver.

trans-Chalcone inhibits high-fat diet-induced disturbances in FXR/SREBP-1c/FAS and FXR/Smad-3 pathways in the kidney of rats

High-fat diet (HFD) intake is linked to chronic kidney disease. Farnesoid X receptor (FXR) controls the renal lipid metabolism and fibrosis. The purpose of the current study was to evaluate the possible impacts of trans-chalcone on HFD-induced changes in renal lipid metabolism and Smad-3 expression through the regulation of FXR expression. To this aim, 28 rats were randomly divided into control, chalcone, HFD, and HFD + chalcone groups. At the end of treatments, renal FXR, sterol regulatory element-binding protein (SREBP)-1c, fatty acid synthase (FAS), Smad-3, and neutrophil gelatinase-associated lipocalin (NGAL) expression levels were assayed. Moreover, insulin sensitivity check index (QUICKI) was calculated. trans-Chalcone significantly inhibited HFD-induced reduction of insulin sensitivity. Moreover, HFD decreased the FXR expression, and trans-chalcone reversed this change. trans-Chalcone also inhibited HFD-induced increases in expression levels of SREBP-1c, FAS, Smad-3, and NGAL. Therefore, trans-chalcone, as a renoprotective agent, inhibits HFD-induced disturbances in FXR/SREBP-1c/FAS and FXR/Smad-3 pathways. PRACTICAL APPLICATIONS: Non-alcoholic fatty liver disease and metabolic syndrome, two health concerns with increasing prevalence, are known as important risk factors for chronic kidney disease. The current study indicated the preventive effect of trans-chalcone administration on HFD-induced disturbances in renal FXR/SREBP-1c/FAS and FXR/Smad-3 pathways. According to these results, trans-chalcone can be regarded as a renoprotective functional food component that can protect individuals with metabolic syndrome against chronic renal disease.

Protective Effect of Trans-chalcone Against High-Fat Diet-Induced Pulmonary Inflammation Is Associated with Changes in miR-146a And pro-Inflammatory Cytokines Expression in Male Rats

High-fat diet (HFD) increases the risk of non-communicable inflammatory diseases including pulmonary disorders. Trans-chalcone is a chalcone with antioxidant and anti-inflammatory effects. This study aimed to explore the effect of this natural compound and molecular mechanism of its effect on HFD-induced pulmonary inflammation. Twenty-eight male Wistar rats were randomly divided into four main groups (n = 7 per each group): control, receiving 10% tween 80; Chal, receiving trans-chalcone, HFD, receiving a high-fat emulsion and 10% tween 80; HFD + Chal, receiving a high-fat emulsion and trans-chalcone. After 6 weeks, the lungs were dissected, and the expression levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and miR-146a were determined using real-time PCR. Moreover, histological analysis was done by hematoxylin and eosin staining. Significant elevations in TNF-α, IL-1β, IL-6, and miR-146a expression levels (P < 0.001) were observed within the lungs of HFD-fed rats compared with the control. However, oral administration of trans-chalcone reduced TNF-α, IL-1β, IL-6 (P < 0.001), and miR-146a (P < 0.05) expression levels and also improved HFD-induced histological abnormalities. These findings indicate that trans-chalcone ameliorates lung inflammatory response and structural alterations. It seems that this beneficial effect is associated with the down-regulation of pro-inflammatory cytokines and miR-146a.

Preventive effect of trans-chalcone on non-alcoholic steatohepatitis: Improvement of hepatic lipid metabolism

Non-alcoholic steatohepatitis (NASH) is an inflammatory and progressive form of non-alcoholic fatty liver disease. However, there are no FDA-approved drugs for this condition. Lipids accumulated in NASH have a direct role in the progression of this disease. Therefore, this study for the first time explored the preventive effect of trans-chalcone on NASH through the modulation of sterol regulatory element binding protein (SREBP)-1c, SREBP-2, hepatic fatty acid synthesis (FAS) enzyme, proliferator-activated receptor (PPAR)-α, and PPAR-γ2 levels, which are involved in hepatic lipid metabolism. In this study, male rats were randomly divided into three groups (n = 7): Control, received 10% tween 80; NASH, received 10% tween 80 and 10 ml/kg high-fat emulsion (high-fat diet, HFD); and NASH + TC, received 20 mg/kg trans-chalcone and 10 ml/kg HFD. All treatments were performed by once-daily oral gavage for 6 weeks. Liver and blood samples were collected and serum levels of alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglyceride, total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol, as well as hepatic levels of SREBP-1c, SREBP-2, FAS, PPAR-α, and PPAR-γ2, were measured. Moreover, hematoxylin and eosin stained tissues were used for histological analysis. In this study, treatment of HFD-fed rats with trans-chalcone significantly reduced abnormalities in liver histology, serum levels of liver injury markers, liver index, and hepatic levels of SREBP-1c, SREBP-2, FAS, and PPAR-γ2. Furthermore, trans-chalcone significantly increased hepatic PPARα levels in these rats. Therefore, it seems that trans-chalcone protects the liver of HFD-fed rats against NASH development through reduction of SREBP-1c/ FAS- and PPAR-γ2-related lipogenesis, attenuation of SREBP-2-related cholesterol synthesis, and elevation of PPARα-related fatty acid oxidation.

trans-Chalcone prevents insulin resistance and hepatic inflammation and also promotes hepatic cholesterol efflux in high-fat diet-fed rats: modulation of miR-34a-, miR-451-, and miR-33a-related pathways

Insulin resistance and inflammation are strongly linked to non-alcoholic fatty liver disease (NAFLD) as a feature of the metabolic syndrome. Furthermore, the role of dysregulation of miR-34a, miR-451, and miR-33a in pathogenesis and progression of NAFLD has been identified. trans-Chalcone is a simple chalcone with anti-diabetic and anti-inflammatory activities. However, to the best of our knowledge, miRNA-dependent mechanisms of these protective effects under pathologic conditions are not understood. Thus, this study, for the first time, aimed to evaluate the effects of trans-Chalcone on miR-34a, miR-451, and miR-33a signaling pathways in the liver of high-fat (HF) emulsion-fed rats. To this aim, twenty-one rats were randomly and equally divided into three groups: control, which was gavaged with 10% tween 80; HF, which was gavaged with HF emulsion and 10% tween 80; and HF + trans-Chalcone (HF + TC), which was gavaged with HF emulsion and trans-Chalcone. Then, circulating levels of glucose and insulin were measured and used for the calculation of HOMA-IR. Hepatic expression levels of miR-34a, miR-451, miR-33a, SIRT1, and ABCA1 and also protein levels of ABCA1 and IL-8 were assayed. In this study, trans-chalcone increased hepatic cholesterol efflux and prevented insulin resistance and liver inflammation in HF emulsion-fed rats. These protective effects were modulated through the down-regulation of miR-34a and its associated elevation of SIRT1, the up-regulation of miR-451 which was associated with a reduction in IL-8, and the inhibition of miR-33a which was related to the elevation of ABCA1 in the liver of HF emulsion-fed rats. Therefore, trans-Chalcone exerts its beneficial effects by targeting hepatic miR-34a-, miR-451-, and miR-33a-related pathways.

Effect of trans-chalcone on hepatic IL-8 through the regulation of miR-451 in male rats

OBJECTIVE

Trans-chalcone is a chalcone with hepatoprotective and anti-inflammatory effects. However, the mechanism of these positive effects, especially on miR-451 as an inflammatory regulator, is poorly understood. In this regard, this microRNA (miRNA) acts by inhibition of hepatic interleukin-8 (IL-8) production in the liver which is one of the main proinflammatory cytokines. Th is study for the first time examined the effect of trans-chalcone on miR-451/IL-8 pathway.

METHODS

In present study, 21 male rats were randomly divided into 3 groups (n=7 per each group): control which received solvent (NS), groups 2 (N2T) and 3 (N6T), which received transchalcone for 2 and 6 weeks, respectively. Hepatic level of miR-451 was measured by qRT-PCR. Serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as well as hepatic level of IL-8 protein were measured.

RESULTS

Trans-chalcone decreased hepatic level of IL-8 protein and serum level of ALT aft er 2 weeks of treatment without significant change in hepatic miR-451. Moreover, it increased hepatic level of miR-451 and reduced hepatic IL-8 as well as AST and ALT aft er 6 weeks.

CONCLUSION

Based on the results of present study, miR-451/IL-8 pathway is a possible mechanism for hepatoprotective action of trans-chalcone in long-term.