Acute kidney injury (AKI) is a clinical syndrome characterized by a rapid decline in renal function. Renal ischemia-reperfusion injury (RIRI) is one of the main causes of AKI with the underlying mechanism incompletely clarified. The liver X receptors (LXRs), including LXRα and LXRβ, are members of the nuclear receptor superfamily. It has been shown that LXRs play an important role in regulating glucose and lipid metabolism, cholesterol efflux, and inflammation. The purpose of this study was to explore the role and mechanism of LXRs in RIRI. We determined the effects of LXR activation on renal function and histological changes in a mouse RIRI model and a cellular model of hypoxia/reoxygenation (H/R). In vivo results showed that LXRs agonist GW3965 significantly inhibited the increase of serum creatinine and urea nitrogen levels induced by RIRI. Both HE and PAS staining of kidney tissues revealed that GW3965 alleviated the morphological damages caused by RIRI. Immunohistochemical staining showed that GW3965 mitigated 4-HNE and GRP78 levels induced by RIRI. Furthermore, TUNEL assay indicated that GW3965 reduced RIRI-induced renal cell apoptosis. Quantitative real-time PCR (qPCR) analysis revealed that GW3965 attenuated RIRI-induced IL-6 and IL-1β mRNA expression. Compared with wild-type group, LXRα gene deficiency had little effect on RIRI-associated renal functional decline and morphological damages. Additionally, in vitro study demonstrated that GW3965 alleviated H/R-induced decrease of HK-2 human renal proximal tubule cell viability and restored the activity of superoxide dismutase (SOD) after H/R. Western blot results showed that GW3965 mitigated the increase of 4-HNE and GRP78 protein expression levels after H/R; However, knockdown of LXRβ using the small interfering RNA (siRNA) technique reduced cell viability compared to GW3965-treated group. Taken together, the LXRs agonist GW3965 significantly alleviates RIRI in mice possibly by reducing apoptosis, oxidative stress, endoplasmic reticulum stress and inflammation. These results also preliminarily confirm that the renal protective effects of LXRs agonists are dependent on LXRβ.
Animals ; Liver X Receptors/genetics* ; Reperfusion Injury/prevention & control* ; Mice ; Benzoates/pharmacology* ; Benzylamines/pharmacology* ; Male ; Endoplasmic Reticulum Chaperone BiP ; Mice, Inbred C57BL ; Apoptosis ; Acute Kidney Injury/prevention & control* ; Kidney/pathology* ; Humans

OBJECTIVES: The liver X receptors (LXRs) are members of the nuclear hormone receptor superfamily, and LXR-β is an important receptor for cholesterol content in brain cells. LXR-β/retinoic X receptor (RXR-α)/ATP binding cassette transporter A1 (ABCA1) cholesterol transmembrane transport system is closely related to the occurrence and development of Alzheimer's disease (AD). LXR agonist TO901317 can affect the accumulation of β- amyloid protein in the brain tissue of APP/PS1 double transgenic AD mice. However, the molecular mechanism is not clarified in detail. This study aims to evaluate the effects of LXR agonist TO901317 on the cognitive function of AD mice fed with high cholesterol diet, and to explore its possible mechanism from the perspective of cholesterol metabolism. METHODS: Twenty four male 6-month-old APP/PS1 double transgenic AD mice were randomly divided into 4 groups, 6 mice in each group: a control group (fed with normal diet), a cholesterol rich diet (CRD) group, a TO901317 group (fed with CRD combined with TO901317), and a GSK2033 group (fed with CRD combined with TO901317 and LXR antagonist GSK2033). The mice were fed with pellet feed made of high cholesterol feed, mixed with lard, egg yolk powder, and cod liver oil twice a day. TO901317 and GSK2033 were dissolved and diluted to a final concentration at 0.03%. The drugs were given to the mice daily through gastric tube according to their body weight. Meanwhile, the mice in the drug group were fed with high cholesterol diet . After feeding for 3 months, Morris water maze was used to observe the changes of spatial exploration and memory ability of AD mice in each group. The contents of TC, LDL, and HDL in serum of mice in each group were detected by cholesterol enzyme colorimetry, and the differences among the groups were compared. The expression of Aβ₄₂ in the brain of AD mice was detected by ELISA. Western blotting was used to detect the protein levels of LXR-β, RXR-α, ABCA1, and Caveolin-1 in the brain of each group. RESULTS: Morris water maze results showed that the times, distance and the duration of mice crossing the platform in the CRD group were significantly decreased compared with the control group (all P<0.05), while these three figures in TO901317 group were significantly increased compared with the CRD group (all P<0.05). Compared with the TO901317 group, there was a decrease of these figures in the GSK2033 group (all P<0.05). The serum TC and LDL levels in the CRD group were significantly higher than those in the control group, while HDL levels were significantly lower (all P<0.001). The figures of the TC and LDL contents level in the TO901317 group were lower than those in the CRD group, while HDL levels were higher (all P<0.001). Compared with TO901317 group, the contents of the TC and LDL in GSK2033 group were significantly increased, while HDL content was significantly decreased (all P<0.001). ELISA results showed that the production of Aβ₄₂ peptides in the brain of CRD group was the highest while the content in the TO901317 group was significantly decreased (P<0.001), which was the lowest among the groups. The figure in the control group was close to the GSK2033 group. Western blotting results showed that the protein levels of LXR-β, RXR-α, and ABCA1 in the CRD group were significantly decreased compared with the control group, but the protein level of Caveolin-1 was increased (all P<0.01). After TO901317 treatment, the protein levels of LXR-β, RXR-α and ABCA1 were significantly increased, while the protein level of Caveolin-1 was decreased partially (all P<0.001). In the GSK2033 group, the effect of TO901317 on AD mice was partially reversed by GSK2033. Compared to TO901317 group, the protein levels of LXR-β, RXR-α, and ABCA1 showed a decrease trend, while the protein level of Caveolin-1 showed an increase state (all P<0.05). CONCLUSIONS High cholesterol diet leads to severer spatial exploration, learning and memory impairment in transgenic AD mice, while the LXR agonist TO901317 attenuates this effect. The mechanism may be that TO901317 promotes cholesterol efflux by activating LXR-β/RXR-α/ABCA1 transmembrane transport system, reduces the expression of Caveolin-1, improves the composition of lipid raft, and ultimately reduces the production of Aβ₄₂ in the brain.
Male ; Animals ; Mice ; Liver X Receptors/metabolism* ; Mice, Transgenic ; Alzheimer Disease/genetics* ; Caveolin 1/metabolism* ; Hydrocarbons, Fluorinated/pharmacology* ; Cognition ; Amyloid beta-Peptides/metabolism* ; Cholesterol

OBJECTIVE: To examine the expression of liver X receptor-β (LXR-β) in human gastric cancer tissue, and to explore the effect of GW3965, an agonist of LXRs, on proliferation of gastric cancer cell line SGC-7901.
 METHODS: The immunohistochemical assay was used to detect the expression of LXR-β, activating transcription factor 4 (ATF4) in gastric cancer tissues and the corresponding pericarcinoma tissues in 114 patients. Real-time quantitative PCR and Western blot were used to determine mRNA and protein levels of ATF4 and ATP-binding cassette 1 (ABCA1), one of the downstream target genes of LXRs, in SGC-7901 cells with or without GW3965 treatment. Cell counting kit-8 (CCK-8) assay was performed to detect cell proliferation. The expression of ATF4 was silenced by short hairpin RNA (shRNA).
 RESULTS: The expressions of LXR-β and ATF-4 were obviously down-regulated in the gastric cancer tissues than that in the corresponding pericarcinoma tissues (both P<0.05). Compared with the control cells, GW3965 treatment inhibited proliferation of SGC-7901 cells and up-regulated ATF4 and ABCA1 expressions (both P<0.05). Knockdown of ATF4 can reverse the antiproliferative effect of GW3965 on SGC-7901 cells.
 CONCLUSION The expression of LXR-β is decreased in human gastric cancer tissues, and activation of LXRs by GW3965 could inhibit the proliferation of SGC-7901 cells via ATF4.
Activating Transcription Factor 4 ; genetics ; metabolism ; Benzoates ; pharmacology ; Benzylamines ; pharmacology ; Cell Line, Tumor ; drug effects ; Cell Proliferation ; Gene Expression Regulation, Neoplastic ; Gene Silencing ; Humans ; Liver X Receptors ; Orphan Nuclear Receptors ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; Stomach Neoplasms ; pathology ; Up-Regulation

No abstract available.
Antibodies, Monoclonal, Murine-Derived/therapeutic use ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use ; B-Cell-Specific Activator Protein/metabolism ; Bone Marrow/metabolism/*pathology ; Cyclophosphamide/therapeutic use ; Doxorubicin/therapeutic use ; Endoscopy, Digestive System ; Female ; Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor ; Genetic Loci ; Humans ; Liver/metabolism/pathology ; Lymphocytes/cytology/immunology ; Lymphoma, Large B-Cell, Diffuse/complications/*diagnosis/drug therapy ; Lymphoma, T-Cell, Peripheral/complications/*diagnosis/drug therapy ; Middle Aged ; Prednisone/therapeutic use ; Receptors, Antigen, T-Cell, gamma-delta/genetics ; Tomography, X-Ray Computed ; Vincristine/therapeutic use

OBJECTIVETo investigate whether RNA interference (RNAi) of LXRα gene in donor rats with fatty liver improves liver graft function after transplantation.

METHODSFifty donor SD rats were fed a high-fat diet and 56% alcohol to induce macrovesicular steatosis exceeding 60% in the liver. The donor rats were injected via the portal veins with 7 × 10⁷ TU LXRα-RNAi-LV mixture (n=25) or negative control-LV (NC-LV) vector (n=25) 72 h before orthotopic liver transplantation. At 2, 24, and 72 h after the transplantation, the recipient rats were sacrificed to examine liver transaminases, liver graft histology, immunostaining (TUNEL), and protein and mRNA levels of LXRα.

RESULTSLentivirus-LXRα RNAi inhibited LXRα gene expression at both the mRNA and protein levels in the liver graft and reduced the expressions of SREBP-1c and CD36 as compared with the controls, resulting also in reduced fatty acid accumulation in the hepatocytes. The recipient rats receiving RNAi-treated grafts showed more obvious reduction in serum ALT, AST, IL-1β and TNF-α levels, and exhibited milder hepatic pathologies than the control rats after the transplantation. TUNEL assay demonstrated a significant reduction in cell apoptosis in LXRα-RNAi-LV-treated liver grafts, and the rats receiving treated liver grafts had a prolonged mean overall survival time.

CONCLUSIONLXRα-RNAi-LV treatment of the donor rats with fatty liver can significantly down-regulate LXRα gene expression in the liver graft and improve the graft function and recipient rat survival after liver transplantation.

Animals ; Fatty Liver ; genetics ; surgery ; Gene Expression Regulation ; Hepatocytes ; cytology ; Lentivirus ; Liver ; physiology ; Liver Transplantation ; Liver X Receptors ; Orphan Nuclear Receptors ; genetics ; RNA Interference ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley

BACKGROUNDABCA7 is a member of the ABCA subfamily that shows a high degree of homology to ABCA1 and, like ABCA1, mediates cellular cholesterol and phospholipid release by apolipoproteins when transfected in vitro. However, expression of ABCA7 has been shown to be downregulated by increased cellular cholesterol while ABCA1 was upregulated.

METHODSThe underlying mechanism for this effect was examined in ABCA1 or ABCA7-transfected HEC293. Lipid content in the medium and cells was determined by enzymatic assays. Gene expression was quantitated by real time PCR, and protein content was determined by Western blotting.

RESULTSWhile ABCA7 mRNA was decreased by 25-hydroxycholesterol treatment, ABCA1 was apparently increased. Treatment with the synthetic LXR agonist T0901317 (T09) upregulated ABCA1 expression and apoAI-mediated cellular lipid release in ABCA1-transfected HEC293 cells, but ABCA7 expression and cellular lipid release in ABCA7-transfected HEC293 cells showed no obvious changes.

CONCLUSIONThe ABCA7 gene is regulated by sterol in a direction opposite to that of ABCA1.

ATP Binding Cassette Transporter 1 ; analysis ; genetics ; physiology ; ATP-Binding Cassette Transporters ; analysis ; genetics ; physiology ; Amino Acid Sequence ; Apolipoprotein A-I ; physiology ; Gene Expression Regulation ; HEK293 Cells ; Humans ; Hydrocarbons, Fluorinated ; pharmacology ; Hydroxycholesterols ; pharmacology ; Lipid Metabolism ; Liver X Receptors ; Molecular Sequence Data ; Orphan Nuclear Receptors ; agonists ; Sulfonamides ; pharmacology

Adolescent ; Child ; Child, Preschool ; DNA Mutational Analysis ; Diagnosis, Differential ; Humans ; Infant ; Infant, Newborn ; Liver Diseases ; diagnosis ; genetics ; pathology ; Lung Diseases ; diagnosis ; genetics ; pathology ; Magnetic Resonance Imaging ; Mutation ; Polycystic Kidney, Autosomal Dominant ; diagnosis ; genetics ; pathology ; Polycystic Kidney, Autosomal Recessive ; diagnosis ; genetics ; pathology ; Prenatal Diagnosis ; Receptors, Cell Surface ; genetics ; Tomography, X-Ray Computed

AIM: Silybin (SB), a major constituent of the milk thistle, has been used to treat several liver disorders. However, liver diseases were always accompanied by CYP450 dysfunction. This study was designed to explore the relationship between the hepatoprotective effect and CYP3A regulation of SB during thioacetamide (TAA)-induced rat liver injury. METHODS: Serum biochemical analysis and histopathological study were taken to evaluate the hepatoprotectinve effect of SB. α-SMA were detected by immunohistochemical analysis and cytokine release in rat liver was determined by ELISA assay. CYP3A and PXR expression were determined by RT-PCR and Western blot analysis, and CYP3A activity was based on the midazolam 4-hydroxylation reaction. Also, siRNA transfection was induced in HepG2 cells to evaluate the effect of PXR on cytotoxicity and CYP3A4 dysregulation caused by TAA. RESULTS: SB showed powerful hepatoprotective effects, and anti-inflammatory and anti-fibrosis effects, and reversed the loss of CYP3A and PXR in TAA-injured rat liver, and decreased PXR translocation into the cell nucleus. PXR silencing weakened the effect of SB on cytoprotection and CYP3A regulation. CONCLUSIONS PXR was a very important factor of CYP3A regulation and might be the target of SB in TAA-induced liver disease. Also, because of the potential interactions of SB and co-administered medicines, it might be necessary to adjust the dosage in the clinical medication of liver disease.
Animals ; Chemical and Drug Induced Liver Injury ; drug therapy ; enzymology ; Cytochrome P-450 CYP3A ; genetics ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Liver ; drug effects ; enzymology ; metabolism ; Male ; Milk Thistle ; chemistry ; Pregnane X Receptor ; Rats ; Rats, Sprague-Dawley ; Receptors, Steroid ; genetics ; metabolism ; Signal Transduction ; drug effects ; Silybin ; Silymarin ; administration & dosage ; Thioacetamide ; adverse effects

BACKGROUNDThe gradually increasing changes in a human hyperlipidemic diet along with chronic stress might play an important role in the increased numbers of fatty liver. This study investigated the effects of Ilex asprella root decoction on related genes of lipid metabolism in chronic stress in hyperlipidemic fatty liver in rats.

METHODSForty-eight male Wistar rats were randomly divided into four groups: normal control group, model control group, simvastatin group, and Ilex asprella root group. To establish chronic stress and hyperlipidemic fatty liver models in rats, the levels of serum lipids, glucose, liver index, insulin (INS), insulin resistant (IR) index, adiponectin, superoxide dismutase (SOD), glutathione peroxidase (GSH-pX), glutathione (GSH), liver X receptor (LXR), and sterol responsive element binding protein (SREBP)-1c in rats were measured.

RESULTSWhen compared to the normal control group, the levels of serum lipids, glucose, liver index, INS, IR index, and GSH in the model control group significantly increased (P < 0.01). The protein levels of LXRα and SREBP-1c increased (P < 0.05), and the serum adiponectin and the SOD and GSH-pX decreased significantly (P < 0.01). When compared to the model control group, the levels of serum lipids, glucose, liver index, INS, IR index, SOD, and GSH-pX in the simvastatin group and Ilex asprella root group increased in varying degrees (P < 0.01 or 0.05); the serum adiponectin and GSH decreased (P < 0.05), while the protein levels of LXRα and SREBP-1c decreased in varying degrees (P < 0.01 or 0.05). When compared to the simvastatin group, the IR index and protein levels of LXRα in the Ilex asprella root group decreased (P < 0.05), and the serum adiponectin and SOD increased (P < 0.05).

CONCLUSIONThe Ilex asprella root decoction has some protective effects on regulating the related genes of lipid metabolism caused by chronic stress and hyperlipidemic fatty liver in rats.

Animals ; Fatty Liver ; drug therapy ; metabolism ; Hyperlipidemias ; drug therapy ; metabolism ; Ilex ; chemistry ; Lipid Metabolism ; drug effects ; Lipid Peroxidation ; drug effects ; Liver X Receptors ; Male ; Orphan Nuclear Receptors ; genetics ; Plant Extracts ; chemistry ; Plant Roots ; chemistry ; Rats ; Rats, Wistar ; Reverse Transcriptase Polymerase Chain Reaction ; Sterol Regulatory Element Binding Protein 1 ; genetics

OBJECTIVETo investigate the effect of liver X receptor agonist T0901317 on transforming growth factor-β1 (TGF-β1)-induced expression of α-smooth muscle actin (α-SMA) in normal human lung fibroblasts.

METHODSPrimary normal human lung fibroblast isolated from the lung specimens of lung cancer patients by explant culture technique were identified with immunostaining for vimentin and keratin. The cells in passages 4 to 10 were treated with T0901317 and/or TGF-β1, and RT-PCR, Western blotting and immunofluorescence assay were used to detect α-SMA expression in the fibroblasts.

RESULTSLung fibroblast expressed vimentin but not keratin. The results of RT-PCR, Western blotting and immunofluorescence assay all showed that normal human lung fibroblasts constitutively expressed α-SMA under baseline condition, and TGF-β1 at 5 ng/ml induced a significant upregulation of α-SMA both at the mRNA and protein levels. Liver X receptor agonist T0901317 (5 µg/ml) significantly inhibited TGF-β1-induced upregulation of α-SMA expression.

CONCLUSIONLiver X receptor agonist T0901317 can inhibit the upregulation of α-SMA in normal human lung fibroblasts induced by TGF-β1, suggesting the potential value of liver X receptor agonist in the treatment of lung fibrosis.

Actins ; metabolism ; Cells, Cultured ; Female ; Fibroblasts ; drug effects ; metabolism ; Humans ; Hydrocarbons, Fluorinated ; pharmacology ; Liver X Receptors ; Lung ; cytology ; Middle Aged ; Orphan Nuclear Receptors ; agonists ; RNA, Messenger ; genetics ; Sulfonamides ; pharmacology ; Transforming Growth Factor beta1 ; pharmacology