HMG-CoA reductase inhibitors (statins) activate expression of PPARalpha/PPARgamma and ABCA1 in cultured gallbladder epithelial cells

Pravastatin Reduces Matrix Metalloproteinases Expression and Promotes Cholesterol Efflux in Osteoarthritis Chondrocytes

Background

Chondrocyte metabolic disorder plays an important role in the development of osteoarthritis (OA). The use of statins in the treatment of OA has also been widely studied, but the mechanism is still confusing. The present study aims to investigate the effects of statin on osteoarthritis chondrocytes and its underlying mechanism. Major findings. An untargeted metabolomics study revealed that the treatment of statins significantly changed the metabolites of articular cartilage tissues collected from female osteoarthritis patients, and might be involved in the glycerophospholipid metabolism pathway. In vitro study showed that 5-50 μmol/L of pravastatin exerts no cytotoxicity on human chondrocytes. Besides, 50 μmol/L of pravastatin caused a significant decrease in the expression of matrix metalloproteinase (MMP)-1 and MPP-13, and intracellular cholesterol in interleukin-1β (IL-1β)-induced human chondrocytes. Furthermore, at both mRNA and protein levels, the expression of the proteins related to the cholesterol efflux pathway (liver X receptor and cholesterol efflux regulatory protein) were significantly up-regulated by 50 μmol/L of pravastatin in IL-1β-induced human chondrocytes.

Conclusion

Pravastatin can reduce the expression of MMPs in IL-1β-induced human chondrocytes and protect the chondrocyte matrix. The mechanism may be related to promoting the expression of proteins related to the cholesterol efflux pathway and reducing the level of cellular cholesterol.

Co-Administration of Vitamin E and Atorvastatin Improves Insulin Sensitivity and Peroxisome Proliferator-Activated Receptor-γ Expression in Type 2 Diabetic Patients: A Randomized Double-Blind Clinical Trial

Background

Negative effects of statins on glucose metabolism have been reported. The present study aimed to investigate the effects of co-administration of vitamin E and atorvastatin on glycemic control in hyperlipidemic patients with type 2 diabetes mellitus (T2DM).

Methods

A randomized double-blind clinical trial was conducted at Vali-e-Asr Teaching Hospital (Zanjan, Iran) from July 2017 to March 2018. A total of 30 T2DM female patients were allocated to two groups, namely atorvastatin with placebo (n=15) and atorvastatin with vitamin E (n=15). The patients received daily 20 mg atorvastatin and 400 IU vitamin E or placebo for 12 weeks. Anthropometric and biochemical measures were recorded pre- and post-intervention. Peroxisome proliferator-activated receptor-γ (PPAR-γ) expression was measured in peripheral blood mononuclear cells (PBMCs). Independent sample t test and paired t test were used to analyze between- and within-group variables, respectively. The analysis of covariance (ANCOVA) was used to adjust the effect of baseline variables on the outcomes. P<0.05 was considered statistically significant.

Results

After baseline adjustment, there was a significant improvement in homeostatic model assessment for insulin resistance (HOMA-IR) (P=0.04) and serum insulin (P<0.001) in the atorvastatin with vitamin E group compared to the atorvastatin with the placebo group. In addition, co-administration of vitamin E with atorvastatin significantly upregulated PPAR-γ expression (OR=5.4, P=0.04) in the PBMCs of T2DM patients.

Conclusion

Co-administration of vitamin E and atorvastatin reduced insulin resistance and improved PPAR-γ mRNA expression. Further studies are required to substantiate our findings.

Trial registration number

IRCT 20170918036256N.

Biology of Cholangiocytes: From Bench to Bedside

Cholangiocytes, the lining epithelial cells in bile ducts, are an important subset of liver cells. They are activated by endogenous and exogenous stimuli and are involved in the modification of bile volume and composition. They are also involved in damaging and repairing the liver. Cholangiocytes have many functions including bile production. They are also involved in transport processes that regulate the volume and composition of bile. Cholangiocytes undergo proliferation and cell death under a variety of conditions. Cholangiocytes have functional and morphological heterogenecity. The immunobiology of cholangiocytes is important, particularly for understanding biliary disease. Secretion of different proinflammatory mediators, cytokines, and chemokines suggests the major role that cholangiocytes play in inflammatory reactions. Furthermore, paracrine secretion of growth factors and peptides mediates extensive cross-talk with other liver cells, including hepatocytes, stellate cells, stem cells, subepithelial myofibroblasts, endothelial cells, and inflammatory cells. Cholangiopathy refers to a category of chronic liver diseases whose primary disease target is the cholangiocyte. Cholangiopathy usually results in end-stage liver disease requiring liver transplant. We summarize the biology of cholangiocytes and redefine the concept of cholangiopathy. We also discuss the recent progress that has been made in understanding the pathogenesis of cholangiopathy and how such progress has influenced therapy.

Simvastatin modulates gene expression of key receptors in zebrafish embryos

Nuclear receptors (NR) are involved in the regulation of several metabolic processes and it is well known that these constituents may be modulated by different chemicals classes, including pharmaceuticals that may activate or antagonize NR. In mammals, some pharmaceuticals modulate the transcription of pregnane X receptor, Pxr, peroxisome proliferator activated receptor, Ppars, and aryl hydrocarbon receptor, Ahr, affecting mRNA expression of genes belonging to various regulatory pathways, including lipid metabolism and detoxification mechanisms. The aim of this study was to determine the effects of simvastatin (SIM), an anticholesterolemic drug, on selected NR and AhR mRNA transcription levels during zebrafish early development. Embryos were collected at different development stages (0, 2, 6, 14, 24, 48, and 72 hr post fertilization (hpf)) and mRNA of all target NR was detected at all time points. Embryos (1 and 24 hpf) were exposed to different concentrations of SIM (5 or 50 μg/L) in two differing assays with varying exposure times (2 or 80 hr). The transcription levels of ahr2, raraa, rarab, rarga, pparαa, pparβ1, pparγ, pxr, rxraa, rxrab, rxrbb, rxrga, rxrgb, as well as levels of cholesterol (Chol) were measured after exposure. SIM exerted no marked effect on Chol levels, and depending upon exposure duration mRNA levels of NR and AhR either increased or decreased. After 2 hr SIM treatment in 24 hpf embryos, transcription of ppars, pxr, and ahr was up-regulated, while after 80 hr mRNA levels of pxr and ahr were decreased with no marked changes in ppars. Data demonstrate that SIM produced alterations in gene expression of NR which are involved in varying physiological functions and that may disturb regulation of different physiological processes which might impair fish survival and ecosystems regeneration.

Simvastatin Induces Apoptosis and Suppresses Insulin-Like Growth Factor 1 Receptor in Bile Duct Cancer Cells

Background/Aims

Statins act as antineoplastic agents through the inhibition of cell proliferation. This study sought to demonstrate the effects of statins on extrahepatic bile duct cancer cell apoptosis and to document the changes in protein expression involved in tumor growth and suppression.

Methods

Human extrahepatic bile duct cancer cells were cultured. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed to determine the effect of statins on cell proliferation. Apoptosis was measured by a cell death detection enzyme-linked immunosorbent assay and caspase-3 activity assay, and flow cytometry was used to determine the percentage of cells in each phase of the cell cycle. The protein expression of Bax, Bcl-2, insulin-like growth factor 1 (IGF-1) receptor, extracellular signal-regulated kinase 1/2 (ERK1/2), and Akt was measured by Western blot analysis.

Results

Simvastatin suppressed cell proliferation by inducing G1 phase cell cycle arrest in bile duct cancer cells. Furthermore, it induced apoptosis via caspase-3 activation, downregulated the expression of the Bcl-2 protein, and enhanced the expression of the Bax protein. Moreover, simvastatin suppressed the expression of the IGF-1 receptor and IGF-1-induced ERK/Akt activation.

Conclusions

Simvastatin induces apoptosis in bile duct cancer cells, which suggests that it could be an antineoplastic agent for bile duct cancer.

Simvastatin induces cell cycle arrest and inhibits proliferation of bladder cancer cells via PPARγ signalling pathway

Simvastatin is currently one of the most common drugs for old patients with hyperlipidemia, hypercholesterolemia and atherosclerotic diseases by reducing cholesterol level and anti-lipid properties. Importantly, simvastatin has also been reported to have anti-tumor effect, but the underlying mechanism is largely unknown. We collected several human bladder samples and performed microarray. Data analysis suggested bladder cancer (BCa) was significantly associated with fatty acid/lipid metabolism via PPAR signalling pathway. We observed simvastatin did not trigger BCa cell apoptosis, but reduced cell proliferation in a dose- and time-dependent manner, accompanied by PPARγ-activation. Moreover, flow cytometry analysis indicated that simvastatin induced cell cycle arrest at G0/G1 phase, suggested by downregulation of CDK4/6 and Cyclin D1. Furthermore, simvastatin suppressed BCa cell metastasis by inhibiting EMT and affecting AKT/GSK3β. More importantly, we found that the cell cycle arrest at G0/G1 phase and the alterations of CDK4/6 and Cyclin D1 triggered by simvastatin could be recovered by PPARγ-antagonist (GW9662), whereas the treatment of PPARα-antagonist (GW6471) shown no significant effects on the BCa cells. Taken together, our study for the first time revealed that simvastatin inhibited bladder cancer cell proliferation and induced cell cycle arrest at G1/G0 phase via PPARγ signalling pathway.

Therapeutic Effect of Adipose Derived Stem Cells versus Atorvastatin on Amiodarone Induced Lung Injury in Male Rat

Background and Objectives

Amiodarone (AM), a class 3 antiarrhythmic drug, has been associated with variety of adverse effects, the most serious of which is pulmonary toxicity. Ator (A) is a statin, known for their immunomodulatory and anti-inflammatory activities. Recent studies provide evidence of potential therapeutic effect of statins on lung injury. Adipose derived stem cells (ADSCs) have shown great promise in the repair of various tissues. The present study aimed at investigating and comparing the possible therapeutic effect of A and ADSCs on AM induced lung injury in albino rats.

Methods and Results

34 adult male albino rats were divided into 5 groups: control group (Gp I), A group (Gp II) received 10 mg/kg of A orally 6 days (d)/week (w) for 4 weeks (ws), AM group (Gp III) received 30 mg/kg of AM orally 6 d/w for 4 ws, AM&A group (Gp IV) received AM for 4ws then A for other 4 ws and AM&SCs group (Gp V) received AM for 4 ws then injected with 0.5 ml ADSCs on 2 successive days intravenously (IV). Histological, histochemical, immunohistochemical and morphometric studies were performed. Group III displayed bronchiolitis obliterans, thickened interalveolar septa (IAS) and thickened vascular wall which were proven morphometrically. Increased area% of collagen fibers and apoptotic changes were recorded. All findings regressed on A administration and ADSCs therapy.

Conclusion

Ator proved a definite ameliorating effect on the degenerative, inflammatory, apoptotic and fibrotic changes induced by AM. ADSCs administration denoted more remarkable therapeutic effect compared to A.

Atorvastatin attenuates the paraquat-induced pulmonary inflammation via PPARγ receptors: a new indication for atorvastatin

This study was carried out to highlight the role of PPARγ receptors and atorvastatin's protective effect on paraquat (PQ)-induced inflammation in the lungs. Forty-two male Wistar rats were exposed either against saline as control or PQ (3.5 mg/kg, IP) as test groups for 14 days. The test groups were nominated as: PQ, pioglitazone (PGT, 10 mg/kg, orally), atorvastatin (STN, 10 mg/kg, orally), PGT+STN, PGT+GW9662 (1 mg/kg) and STN+GW9662 (1 mg/kg). PGT and STN significantly (P<0.05) reduced the PQ-elevated myeloperoxidase activity, nitric oxide and malondialdehyde contents of the lungs and IL-6 and TNF-α concentrations in serum. Histopathological studies revealed alveolar edema and hemorrhages along with hyaline exudates in alveoli confirming that PGT and STN reduced the damages. Immunohistochemistry studies showed that the PQ-induced inflammation resulted in a severe recruitment of CD68(+) macrophages, which PGT and STN remarkably diminished them. STN regulated the PQ-up-regulated COX-2 expression. The antagonistic effect of GW9662 as an absolute antagonist of PPARγ receptors on anti-inflammatory effect of STN in the regulation of COX-2 expression was observed. These data provide a molecular proof(s) of the STN-produced protective effects on the PQ-induced pulmonary inflammation, which is antagonized by PPARγ antagonist indicating its anti-inflammatory effects via PPARγ receptors. Moreover, a new indication for atorvastatin is suggested.

Pravastatin activates the expression of farnesoid X receptor and liver X receptor alpha in Hep3B cells

BACKGROUND

Statins are suggested to preserve gallbladder function by suppressing pro-inflammatory cytokines and preventing cholesterol accumulation in gallbladder epithelial cells. They also affect cross-talk among the nuclear hormone receptors that regulate cholesterol-bile acid metabolism in the nuclei of hepatocytes. However, there is controversy over whether or how statins change the expression of peroxisome proliferator-activated receptor (PPAR)alpha, PPARgamma, liver X receptor alpha (LXRalpha), farnesoid X receptor (FXR), ABCG5, ABCG8, and 7alpha-hydroxylase (CYP7A1) which are directly involved in the cholesterol saturation index in bile.

METHODS

Human Hep3B cells were cultured on dishes. MTT assays were performed to determine the appropriate concentrations of reagents to be used. The protein expression of PPARalpha and PPARgamma was measured by Western blotting analysis, and the mRNA expression of LXRalpha, FXR, ABCG5, ABCG8 and CYP7A1 was estimated by RT-PCR.

RESULTS

In cultured Hep3B cells, pravastatin activated PPARalpha and PPARgamma protein expression, induced stronger expression of PPARgamma than that of PPARalpha, increased LXRalpha mRNA expression, activated ABCG5 and ABCG8 mRNA expression mediated by FXR as well as LXRalpha, enhanced FXR mRNA expression, and increased CYP7A1 mRNA expression mediated by the PPARgamma and LXRalpha pathways, together or independently.

CONCLUSION

Our data suggested that pravastatin prevents cholesterol gallstone diseases via the increase of FXR, LXRalpha and CYP7A1 in human hepatocytes.

Antifibrotic effect of atorvastatin on paraquat-induced pulmonary fibrosis: role of PPARγ receptors

This study was carried out to highlight the role of PPARγ in the paraquat (PQ)-induced pulmonary fibrosis. Forty-two male Wistar rats were exposed either against saline as a control group or PQ (3.5mg/kg, i.p.) as test groups. The test groups were nominated as PQ (PQ-exposed non-treated animals), pioglitazone (PGT, 10mg/kg, orally), atorvastatin (STN, 10mg/kg, orally), PGT+STN, PGT+GW9662 (1mg/kg, i.p.) and STN+GW9662 (1mg/kg). Atorvastatin but not PGT was able to reverse significantly (P<0.05) the PQ-increased ratio of lung to body weight. STN was successfully able to recover the PQ-reduced antioxidant potency and the GW9662 administration resulted in antagonizing the protective effect of both PGT and STN. Although both PGT and STN were able to reduce the hydrxoproline content of the lungs, GW9662, however, could reverse only STN-related effect. Histochemical studies revealed that PQ exposure resulted in a remarkable increase of fibroblasts and collagen fibers in the interstitial tissue and around vessels and bronchioles, which was improved by the STN administration. Only STN-received animals showed the down-regulation of the TGF-β1 expression and GW9662 was able to antagonize this down-regulation. Co-administration of PGT and STN could not exert any synergistic protective effect. These data suggest that the PQ-induced pulmonary fibrosis could be more effectively reversed by STN rather than PGT. Moreover, STN-induced protective effects might attribute to the regulation of TGF-β1 expression, which is antagonized by PPARγ antagonist, suggesting that STN may improve the PQ-induced damages via PPARγ.

Atorvastatin up-regulate toxicologically relevant genes in rainbow trout gills

There are large and increasing discharges of statins into the aquatic environment. Statins are cholesterol-lowering pharmaceuticals, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, an enzyme in the cholesterol synthesis pathway. Earlier studies have shown that statins will affect the expression of a range of genes in mammalian tissues and this group of pharmaceuticals has also been shown to affect membrane transporters. Changes in gene expression and ion transport in aquatic organisms may have dramatic consequences for the individual. The aim of the present study was to clarify whether waterborne exposure to a selected statin, atorvastatin, would affect gene expression in rainbow trout (Oncorhynchus mykiss) gill or liver or ion regulation in gills. Juvenile rainbow trout were exposed to two atorvastatin acid and atorvastatin lactone concentrations for 7 days (nominal concentrations 200 ng L(-1) and 10 μg L(-1)). The exposures caused up-regulated gene expression in gill, not liver, and only at the lowest concentration. Genes involved in membrane transport (pgp, mrp1), oxidative stress response (sod, mt), apoptosis (bax) and biotransformation (sult2b) were differentially expressed whereas the expression of genes involved in cholesterol biosynthesis (hmgr, fdps) or peroxisomal proliferation (ppar) were not affected. There were no significant changes in gill Na(+)/K(+) ATPase activity following exposure to atorvastatin. The pattern of differentially expressed genes in rainbow trout gills differ from responses previously observed in mammalian tissues following statin exposure.

Pravastatin activates PPARalpha/PPARgamma expression in the liver and gallbladder epithelium of hamsters

BACKGROUND

Our earlier study with cultured gallbladder epithelial cells demonstrated that statins (HMG-CoA reductase inhibitors) activate the expression of PPARalpha and PPARgamma, consequently blocking the production of pro-inflmmatory cytokines. The present study used hamsters to investigate the effects of pavastatin on PPARalpha/PPARgamma expression in the liver and gallbladder epithelium, and to determine whether pravastatin suppresses cholesterol crystal formation in the gallbladder.

METHODS

A total of 40 Golden Syrian male hamsters (4 weeks old) were randomly assigned to four groups (basal diet control; basal diet+pavastatin; high cholesterol diet; high cholesterol diet+pravastatin). All hamsters were 11 weeks old at the end of the experiment. The liver, gallbladder and bile were harvested. Immunohistochemical staining and Western blotting for PPARalpha and PPARgamma were performed in the liver and gallbladder. A drop of fresh bile was examined for cholesterol crystals under a microscope.

RESULTS

In the gallbladder and liver of the hamsters, pravastatin activated the PPARalpha and PPARgamma expression of gallbladder epithelial cells and hepatocytes, and particularly the response of PPARgamma was much stronger than that of PPARalpha. Pravastatin suppressed the formation of cholesterol gallstones or crystals in the gallbladder.

CONCLUSION

Pravastatin is an effective medication to activate PPARs (especially PPARgamma) in the liver and the gallbladder epithelium of hamsters, and contributes to the prevention of gallstone formation.