This study aimed to investigate the role of fatty acid synthase (FASN) in the epithelial-mesenchymal transition (EMT) of breast cancer cells. MCF-7 cells and MCF-7 cells overexpressing mitogen-activat Show more
This study aimed to investigate the role of fatty acid synthase (FASN) in the epithelial-mesenchymal transition (EMT) of breast cancer cells. MCF-7 cells and MCF-7 cells overexpressing mitogen-activated protein kinase 5 (MCF-7-MEK5) were used in this study. MCF-7-MEK5 cells showed stable EMT characterized by increased vimentin and decreased E-cadherin expression. An In vivo animal model was established using the orthotopic injection of MCF-7 or MCF-7-MEK5 cells. Real-time quantitative PCR and western blotting were used to detect the expression levels of FASN and its downstream proteins liver fatty acid-binding protein (L-FABP) and VEGF/VEGFR-2 in both in vitro and in vivo models (nude mouse tumor tissues). In MCF-7-MEK5 cells, significantly increased expression of FASN was associated with increased levels of L-FABP and VEGF/VEGFR-2. Cerulenin inhibited MCF-7-MEK5 cell migration and EMT, and reduced FASN expression and down-stream proteins L-FABP, VEGF, and VEGFR-2. MCF-7-MEK5 cells showed higher sensitivity to Cerulenin than MCF-7 cells. Immunofluorescence revealed an increase of co-localization of FASN with VEGF on the cell membrane and with L-FABP within MCF-7-MEK5 cells. Immunohistochemistry further showed that increased percentage of FASN-positive cells in the tumor tissue was associated with increased percentages of L-FABP- and VEGF-positive cells and the Cerulenin treatment could reverse the effect. Altogether, our results suggest that FASN is essential to EMT possibly through regulating L-FABP, VEGF and VEGFR-2. This study provides a theoretical basis and potential strategy for effective suppression of malignant cells with EMT. Show less
A better understanding of the molecular mechanisms that regulate adipose tissue-derived stromal cell (ADSC) differentiation could provide new insight into some adipose-tissue-related disease. The diff Show more
A better understanding of the molecular mechanisms that regulate adipose tissue-derived stromal cell (ADSC) differentiation could provide new insight into some adipose-tissue-related disease. The differentiation of ADSCs into adipocytes is a complex physiological process that includes clonal expansion, growth arrest, and terminal differentiation. Here the role of microRNA-143 (miR-143) during ADSC adipogenic differentiation was systematically investigated. We found that miR-143 expression was transiently decreased after adipogenic induction while increased from day 3 and peaked on day 7 after induction. We show for the first time that the role of miR-143 is not consistent in the differentiation process. The regulatory role depends on the differentiation stage that miR-143 acts on. When miR-143 is overexpressed during the clonal expansion stage, the adipogenic differentiation of ADSCs is inhibited, whereas the overexpression of miR-143 during the growth arrest stage or terminal differentiation stage promotes differentiation. Further we firstly demonstrate that miR-143 plays the modulational role by directly repressing MAP2K5, a key member of the MAPKK family in the MAPK signaling pathway. These findings suggest that miR-143 plays an important role in adipose tissue formation, with special implications for some metabolic disease in which the amount and/or function of adipose tissue is altered. Show less
Recent genome-wide association studies have shown associations between multiple genetic variants and primary restless legs syndrome (RLS). Their roles in end stage renal disease (ESRD) related seconda Show more
Recent genome-wide association studies have shown associations between multiple genetic variants and primary restless legs syndrome (RLS). Their roles in end stage renal disease (ESRD) related secondary RLS are not clear and studies in Asian populations are scarce. The association between candidate genetic variants and uremic RLS was investigated in a large cohort of Taiwanese dialysis patients. Sixteen RLS-related genetic variants at six loci, including MEIS1, BTBD9, MAP2K5/SKOR1, PTPRD, TOX3/BC034767 and the intergenic region of chromosome 2p14, in a total of 993 ESRD patients (259 subjects with and 734 subjects without RLS) were genotyped using TaqMan genotyping assays. Multivariate logistic regression analysis was used to test for associations between the genotypes and RLS in ESRD. Power calculations were completed using the CATs Genetic Power Calculator with settings of a multiplicative genetic model. A modest association between the PTPRD variant rs4626664 and uremic RLS (odds ratio 1.52, 95% CI 1.03-2.23, P = 0.03) and a trend that TOX3/BC034767 variant rs3104767 may associate with the occurrence of RLS were observed in our dialysis population (odds ratio 1.74, 95% CI 0.97-3.11, P = 0.06). No associations between other genetic variants and risk and severity of RLS were observed in our ESRD cohort. The genetic variants of primary RLS candidate genes did not play a major role in our uremic RLS populations. The ethnic difference and heterogeneous etiologies underlying renal failure may partly explain the minor genetic contribution to uremic RLS in our populations. Further studies for other ethnicities will be of worth. Show less
To investigate whether alpha-lipoic acid (ALA) could attenuate the insulin resistance and metabolic disorders in high fat diet-fed mice. Male mice were fed a high fat diet (HFD) plus ALA (100 and 200 Show more
To investigate whether alpha-lipoic acid (ALA) could attenuate the insulin resistance and metabolic disorders in high fat diet-fed mice. Male mice were fed a high fat diet (HFD) plus ALA (100 and 200 mg·kg(-1)·d(-1)) or HFD plus a positive control drug metformin (300 mg·kg(-1)·d(-1)) for 24 weeks. During the treatments, the relevant physiological and metabolic parameters of the mice were measured. After the mice were euthanized, blood samples and livers were collected. The expression of proteins and genes related to glucose metabolism in livers were analyzed by immunoblotting and real time-PCR. HFD induced non-alcoholic fatty liver disease (NAFLD) and abnormal physiological and metabolic parameters in the mice, which were dose-dependently attenuated by ALA. ALA also significantly reduced HFD-induced hyperglycemia and insulin resistance in HFD-fed mice. Furthermore, ALA significantly upregulated the glycolytic enzymes GCK, HK-1 and PK, and the glycogen synthesis enzyme GS, and downregulated the gluconeogenic enzymes PEPCK and G6Pase, thus decreased glucose production, and promoted glycogen synthesis and glucose utilization in livers. Moreover, ALA markedly increased PKB/Akt and GSK3β phosphorylation, and nuclear carbohydrate response element binding protein (ChREBP) expression in livers. Metformin produced similar effects as ALA in HFD-fed mice. ALA is able to sustain glucose homeostasis and prevent the development of NAFLD in HFD-fed mice. Show less
Diabetic patients have increased levels of advanced glycation end products (AGEs) and the role of AGEs in regulating cancer cell proliferation is unclear. Here, we found that treating colorectal and l Show more
Diabetic patients have increased levels of advanced glycation end products (AGEs) and the role of AGEs in regulating cancer cell proliferation is unclear. Here, we found that treating colorectal and liver cancer cells with AGEs promoted cell proliferation. AGEs stimulated both the expression and activation of a key transcription factor called carbohydrate responsive element binding protein (ChREBP) which had been shown to promote glycolytic and anabolic activity as well as proliferation of colorectal and liver cancer cells. Using siRNAs or the antagonistic antibody for the receptor for advanced glycation end-products (RAGE) blocked AGEs-induced ChREBP expression or cell proliferation in cancer cells. Suppressing ChREBP expression severely impaired AGEs-induced cancer cell proliferation. Taken together, these results demonstrate that AGEs-RAGE signaling enhances cancer cell proliferation in which AGEs-mediated ChREBP induction plays an important role. These findings may provide new explanation for increased cancer progression in diabetic patients. Show less
This study aimed to detect the association between the MLX interacting protein-like (MLXIPL), BUD13 homolog (BUD13) and zinc finger protein 259 (ZNF259) single nucleotide polymorphisms (SNPs) and seru Show more
This study aimed to detect the association between the MLX interacting protein-like (MLXIPL), BUD13 homolog (BUD13) and zinc finger protein 259 (ZNF259) single nucleotide polymorphisms (SNPs) and serum lipid levels in the Chinese Mulao and Han populations. Genotyping of 9 SNPs was performed in 825 Mulao and 781 Han participants. The genotype and allele frequencies of ZNF259 rs2075290 and rs964184, and BUD13 rs10790162 SNPs were different between the Mulao and Han populations (P < 0.001). The SNPs of ZNF259 rs2075290 and BUD13 rs10790162 were associated with serum total cholesterol levels; ZNF259 rs2075290 and rs964184, BUD13 rs10790162, and MLXIPL rs3812316 and rs13235543 were associated with triglyceride (TG); and MLXIPL rs35332062 was associated with apolipoprotein (Apo) A1 in the Mulaos (P < 0.006-0.001). However, in the Hans, the SNPs of ZNF259 rs2075290 and BUD13 rs10790162 were associated with serum TG levels; ZNF259 rs2075290 was associated with low-density lipoprotein cholesterol and the ApoA1/ApoB ratio (P < 0.006-0.001). Significant linkage disequilibria were noted among ZNF259 rs2075290 and rs964184 and BUD13 rs10790162, and between MLXIPL rs3812316 and rs13235543 (r(2) > 0.05, P < 0.001). The haplotypes of A-C-G-A-C (rs2075290A-rs964184C-rs10790162G-rs17119975A-rs11556024C) and C-C-C-C (rs799161C-rs35332062C-rs3812316C-rs13235543C) accounted for over half of the % haplotype of each ethnic group. Show less
Xue-Lei Wang, Xiao-Fei Wen, Rong-Bing Li+4 more · 2014 · Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine · Springer · added 2026-04-24
Androgen receptor (AR), a member of nuclear hormone receptor, plays an essential role in the initiation and progression of prostate cancer (PCa). In the present study, by way of immunoprecipitation fo Show more
Androgen receptor (AR), a member of nuclear hormone receptor, plays an essential role in the initiation and progression of prostate cancer (PCa). In the present study, by way of immunoprecipitation followed by mass spectrometry (IP/MS) system, we found that carbohydrate-responsive element-binding protein (Chrebp), a glucose sensor in normal and cancer cells, interacted with AR in LNCaP cells. The interaction was further confirmed by coimmunoprecipitation analysis. Besides, Chrebp is required for the optimal transcriptional activity of AR in promoting the transcription of the prostate-specific antigen (PSA) promoter and messenger RNA (mRNA) expression. Consistently, knockdown of Chrebp using small interfering RNA (siRNA) in LNCaP cells reduced endogenous PSA levels. Together, our study demonstrates that Chrebp interacts with AR and regulates its transcriptional activity. Show less
Dyslipidemia is strongly associated with raised plasma glucose levels and insulin resistance (IR), and genome-wide association studies have identified 95 loci that explain a substantial proportion of Show more
Dyslipidemia is strongly associated with raised plasma glucose levels and insulin resistance (IR), and genome-wide association studies have identified 95 loci that explain a substantial proportion of the variance in blood lipids. However, the loci's effects on glucose-related traits are largely unknown. We have studied these lipid loci and tested their association collectively and individually with fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), and IR in two independent cohorts: 10,995 subjects from LifeLines Cohort Study and 2,438 subjects from Prevention of Renal and Vascular Endstage Disease (PREVEND) study. In contrast to the positive relationship between dyslipidemia and glucose traits, the genetic predisposition to dyslipidemia showed a pleiotropic lowering effect on glucose traits. Specifically, the genetic risk score related to higher triglyceride level was correlated with lower levels of FPG (P = 9.6 × 10(-10) and P = 0.03 in LifeLines and PREVEND, respectively), HbA1c (P = 4.2 × 10(-7) in LifeLines), and HOMA of estimated IR (P = 6.2 × 10(-4) in PREVEND), after adjusting for blood lipid levels. At the single nucleotide polymorphism level, 15 lipid loci showed a pleiotropic association with glucose traits (P < 0.01), of which eight (CETP, MLXIPL, PLTP, GCKR, APOB, APOE-C1-C2, CYP7A1, and TIMD4) had opposite allelic directions of effect on dyslipidemia and glucose levels. Our findings suggest a complex genetic regulation and metabolic interplay between lipids and glucose. Show less
Cancer cells exhibit increased uptake of glucose and glutamine, and rewire the metabolic flux toward anabolic pathways important for cell growth and proliferation. Understanding how this altered metab Show more
Cancer cells exhibit increased uptake of glucose and glutamine, and rewire the metabolic flux toward anabolic pathways important for cell growth and proliferation. Understanding how this altered metabolism is regulated has recently emerged as an intense research focus in cancer biology. O-linked β-N-acetylglucosamine (O-GlcNAc) is a reversible posttranslational modification of serine and/or threonine residues of nuclear and cytosolic proteins. O-GlcNAcylation has been identified in numerous proteins that are involved in many important cellular functions, including transcription, translation, signal transduction, and stress responses. More recently, increasing evidence indicates that O-GlcNAcylation plays important roles in regulating cancer metabolic reprogramming by modifying key transcription factors, metabolic enzymes and major oncogenic signaling pathways. Thus, O-GlcNAcylation emerges as a novel regulatory mechanism linking altered metabolism to cancer pathogenesis. Show less
Hypertrophic cardiomyopathy (HCM) is a primary disorder characterised by asymmetric thickening of septum and left ventricular wall, with a prevalence of 0.2% in the general population. To describe a n Show more
Hypertrophic cardiomyopathy (HCM) is a primary disorder characterised by asymmetric thickening of septum and left ventricular wall, with a prevalence of 0.2% in the general population. To describe a novel mitochondrial DNA mutation and its association with the pathogenesis of HCM. All maternal members of a Chinese family with maternally transmitted HCM exhibited variable severity and age at onset, and were implanted permanent pacemakers due to complete atrioventricular block (AVB). Nuclear gene screening (MYH7, MYBPC3, TNNT2 and TNNI3) was performed, and no potential pathogenic mutation was identified. Mitochondrial DNA sequencing analysis identified a novel homoplasmic 16S rRNA 2336T>C mutation. This mutation was exclusively present in maternal members and absent in non-maternal members. Conservation index by comparison to 16 other vertebrates was 94.1%. This mutation disturbs the 2336U-A2438 base pair in the stem-loop structure of 16S rRNA domain III, which is involved in the assembly of mitochondrial ribosome. Oxygen consumption rate of the lymphoblastoid cells carrying 2336T>C mutation had decreased by 37% compared with controls. A reduction in mitochondrial ATP synthesis and an increase in reactive oxidative species production were also observed. Electron microscopic analysis indicated elongated mitochondria and abnormal mitochondrial cristae shape in mutant cells. It is suggested that the 2336T>C mutation is one of pathogenic mutations of HCM. This is the first report of mitochondrial 16S rRNA 2336T>C mutation and an association with maternally inherited HCM combined with AVB. Our findings provide a new insight into the pathogenesis of HCM. Show less
Zekuan Lu, Xiao-Nan Ma, Hai-Man Zhang+6 more · 2014 · The Journal of biological chemistry · American Society for Biochemistry and Molecular Biology · added 2026-04-24
Class XIX myosin (Myo19) is a vertebrate-specific unconventional myosin, responsible for the transport of mitochondria. To characterize biochemical properties of Myo19, we prepared recombinant mouse M Show more
Class XIX myosin (Myo19) is a vertebrate-specific unconventional myosin, responsible for the transport of mitochondria. To characterize biochemical properties of Myo19, we prepared recombinant mouse Myo19-truncated constructs containing the motor domain and the IQ motifs using the baculovirus/Sf9 expression system. We identified regulatory light chain (RLC) of smooth muscle/non-muscle myosin-2 as the light chain of Myo19. The actin-activated ATPase activity and the actin-gliding velocity of Myo19-truncated constructs were about one-third and one-sixth as those of myosin-5a, respectively. The apparent affinity of Myo19 to actin was about the same as that of myosin-5a. The RLCs bound to Myo19 could be phosphorylated by myosin light chain kinase, but this phosphorylation had little effect on the actin-activated ATPase activity and the actin-gliding activity of Myo19-truncated constructs. Using dual fluorescence-labeled actin filaments, we determined that Myo19 is a plus-end-directed molecular motor. We found that, similar to that of the high-duty ratio myosin, such as myosin-5a, ADP release rate was comparable with the maximal actin-activated ATPase activity of Myo19, indicating that ADP release is a rate-limiting step for the ATPase cycle of acto-Myo19. ADP strongly inhibited the actin-activated ATPase activity and actin-gliding activity of Myo19-truncated constructs. Based on the above results, we concluded that Myo19 is a high-duty ratio molecular motor moving to the plus-end of the actin filament. Show less
Liver X receptor α (LXRα) plays an important role in the cholesterol metabolism process, and LXRα activation can reduce atherosclerosis. In the present study, using an LXRα-GAL4 luciferase reporter sc Show more
Liver X receptor α (LXRα) plays an important role in the cholesterol metabolism process, and LXRα activation can reduce atherosclerosis. In the present study, using an LXRα-GAL4 luciferase reporter screening, we discovered IMB-170, a structural analog of quinazolinone, which showed potent LXRα agonistic activity. IMB-170 significantly activated LXRα, with an EC50 value of 0.27μM. Interestingly, IMB-170 not only increased the expression of ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1), which are related to the reverse cholesterol transport (RCT) process, but also influenced the expression levels of other genes involved in the cholesterol metabolism pathway in many cell lines. Moreover, IMB-170 significantly reduced cellular lipid accumulation and increased cholesterol efflux from RAW264.7 and THP-1 macrophages. Interestingly, compared with TO901317, IMB-170 only slightly increased protein expression levels of lipogenesis-related genes in HepG2 cells, indicating that IMB-170 may have a lower lipogenesis side effect in vivo. These results suggest that IMB-170 showed the selective agonistic activity for LXRα. Moreover, compared with full LXR-agonists, IMB-170 possesses a differential ability to recruit coregulators. This suggests that IMB-170 has distinct interactions with the active sites in the LXRα ligand-binding domain. In summary, IMB-170 is a novel partial LXRα agonist without the classical lipogenesis side effects, which could be used as a potential anti-atherosclerotic leading compound in the future. Show less
To investigate whether RNA interference (RNAi) of LXRα gene in donor rats with fatty liver improves liver graft function after transplantation. Fifty donor SD rats were fed a high-fat diet and 56% alc Show more
To investigate whether RNA interference (RNAi) of LXRα gene in donor rats with fatty liver improves liver graft function after transplantation. Fifty 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. Lentivirus-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. LXRα-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. Show less
The nuclear receptor liver X receptor (LXR) plays an important role in the metabolism and homeostasis of cholesterol, lipids, bile acids, and steroid hormones. In this study, we uncovered a function o Show more
The nuclear receptor liver X receptor (LXR) plays an important role in the metabolism and homeostasis of cholesterol, lipids, bile acids, and steroid hormones. In this study, we uncovered a function of LXRα (NR1H3) in regulating the human hydroxysteroid sulfotransferase SULT2A1, a phase II conjugating enzyme known to sulfonate bile acids, hydroxysteroid dehydroepiandrosterone, and related androgens. We showed that activation of LXR induced the expression of SULT2A1 at mRNA, protein, and enzymatic levels. A combination of promoter reporter gene and chromatin immunoprecipitation assays showed that LXRα transactivated the SULT2A1 gene promoter through its specific binding to the -500- to -258-base pair region of the SULT2A1 gene promoter. LXR small interfering RNA knockdown experiments suggested that LXRα, but not LXRβ, played a dominant role in regulating SULT2A1. In primary human hepatocytes, we found a positive correlation between the expression of SULT2A1 and LXRα, which further supported the regulation of SULT2A1 by LXRα. In summary, our results established human SULT2A1 as a novel LXRα target gene. The expression of LXRα is a potential predictor for the expression of SULT2A1 in human liver. Show less
In nonruminants, the alternative splicing of peroxisome proliferator-activated receptor γ (PPARG) generates PPARG1 and PPARG2 isoforms. Although transcriptional control differences between isoforms ha Show more
In nonruminants, the alternative splicing of peroxisome proliferator-activated receptor γ (PPARG) generates PPARG1 and PPARG2 isoforms. Although transcriptional control differences between isoforms have been reported in human adipose tissue, their roles in ruminant mammary cells are not well known. To assess which of these isoforms is more closely associated with the regulation of mammary lipogenic pathways, their tissue distribution was analyzed and the expression of key genes regulating lipogenic gene networks was measured after overexpression of the 2 isoforms in goat mammary epithelial cells (GMEC). The expression of PPARG2 was markedly greater in adipose tissue, whereas PPARG1 is the main isoform in goat mammary tissue (ratio of PPARG1:PPARG2 was close to 37:1). As was reported in previous work, PPARG1 upregulated the transcription regulators SREBF1 and PPARG and the lipogenic genes FASN, ACACA, and SCD. Along with a tendency for greater expression of AGPAT6, DGAT1, and PLIN2, these data suggest that PPARG1 is the isoform controlling lipogenesis in mammary cells. Addition of the PPARG ligand rosiglitazone (ROSI) to GMEC overexpressing both isoforms upregulated the expression of LPL and CD36, which help control uptake of long-chain fatty acids into mammary cells. Other responses to ROSI addition to GMEC overexpressing PPARG1 and PPARG2 included upregulation of AGPAT6, DGAT1, INSIG1, SREBF1, and NR1H3. Although the data suggest that both PPARG1 and PPARG2 could affect mammary lipogenesis via control of gene expression when stimulated (e.g., by ROSI), the fact that PPARG1 is more abundant in mammary tissue and that its overexpression alone upregulated key lipogenic gene networks suggest that it is the more important isoform in goat mammary cells. Show less
Liver X receptors (LXRs) have been recognized as a promising therapeutic target for atherosclerosis; however, their role in insulin sensitivity is controversial. Adiponectin plays a unique role in mai Show more
Liver X receptors (LXRs) have been recognized as a promising therapeutic target for atherosclerosis; however, their role in insulin sensitivity is controversial. Adiponectin plays a unique role in maintaining insulin sensitivity. Currently, no systematic experiments elucidating the role of LXR activation in insulin function based on adiponectin signaling have been reported. Here, we investigated the role of LXR activation in insulin resistance based on adiponectin signaling, and possible mechanisms. C57BL/6 mice maintained on a regular chow received the LXR agonist, T0901317 (30 mg/kg.d) for 3 weeks by intraperitoneal injection, and differentiated 3T3-L1 adipocytes were treated with T0901317 or GW3965. T0901317 treatment induced significant insulin resistance in C57BL/6 mice. It decreased adiponectin gene transcription in epididymal fat, as well as serum adiponectin levels. Activity of AMPK, a key mediator of adiponectin signaling, was also decreased, resulting in decreased Glut-4 membrane translocation in epididymal fat. In contrast, adiponectin activity was not changed in the liver of T0901317 treated mice. In vitro, both T0901317 and GW3965 decreased adiponectin expression in adipocytes in a dose-dependent manner, an effect which was diminished by LXRα silencing. ChIP-qPCR studies demonstrated that T0901317 decreased the binding of PPARγ to the PPAR-responsive element (PPRE) of the adiponectin promoter in a dose-dependent manner. Furthermore, T0901317 exerted an antagonistic effect on the expression of adiponectin in adipocytes co-treated with 3 µM Pioglitazone. In luciferase reporter gene assays, T0901317 dose-dependently inhibited PPRE-Luc activity in HEK293 cells co-transfected with LXRα and PPARγ. These results suggest that LXR activation induces insulin resistance with decreased adiponectin signaling in epididymal fat, probably due to negative regulation of PPARγ signaling. These findings indicate that the potential of LXR activation as a therapeutic target for atherosclerosis may be limited by the possibility of exacerbating insulin resistance-related disease. Show less
Dietary phytosterols have been successfully used for lowering cholesterol levels, which correlates with the fact that some phytosterols are able to act as liver X receptor (LXR) agonists. Sargassum fu Show more
Dietary phytosterols have been successfully used for lowering cholesterol levels, which correlates with the fact that some phytosterols are able to act as liver X receptor (LXR) agonists. Sargassum fusiforme is an edible marine seaweed well-known for its antiatherosclerotic function in traditional Chinese medicine. In this study, seven phytosterols including fucosterol (1), saringosterol (2), 24-hydroperoxy-24-vinyl-cholesterol (3), 29-hydroperoxy-stigmasta-5,24(28)-dien-3β-ol (4), 24-methylene-cholesterol (5), 24-keto-cholesterol (6), and 5α,8α-epidioxyergosta-6,22-dien-3β-ol (7) were purified and evaluated for their actions on LXR-mediated transcription using a reporter assay. Among these phytosterols, 2 was the most potent compound in stimulating the transcriptional activities of LXRα by (3.81±0.15)-fold and LXRβ by (14.40±1.10)-fold, respectively. Two epimers of 2, 24(S)-saringosterol (2a) and 24(R)-saringosterol (2b), were subsequently separated by semipreparative high-performance liquid chromatography. Interestingly, 2a was more potent than 2b in LXRβ-mediated transactivation ((3.50±0.17)-fold vs (1.63±0.12)-fold) compared with control. Consistently, 2a induced higher expression levels of LXR target genes including key players in reverse cholesterol transport in six cell lines. These data along with molecular modeling suggested that 2a acts as a selective LXRβ agonist and is a potent natural cholesterol-lowering agent. This study also demonstrated that phytosterols in S. fusiforme contributed to the well-known antiatherosclerotic function. Show less
Vascular endothelial injury is a major cause of many cardiovascular diseases. The proliferation and migration of endothelial progenitor cells (EPCs) play a pivotal role in endothelial regeneration and Show more
Vascular endothelial injury is a major cause of many cardiovascular diseases. The proliferation and migration of endothelial progenitor cells (EPCs) play a pivotal role in endothelial regeneration and repair after vascular injury. Recently, liver X receptor (LXR) activation has been suggested as a potential target for novel therapeutic interventions in the treatment of cardiovascular disease. However, the effects of LXR activation on endothelial regeneration and repair, as well as EPC function, have not been investigated. In the present study, we demonstrate that LXRs, including LXRα and LXRβ, are expressed and functional in rat bone marrow-derived EPCs. Treatment with an LXR agonist, TO901317 (TO) or GW3965 (GW), significantly increased the proliferation and migration of EPCs, as well as Akt and eNOS phosphorylation in EPCs. Moreover, LXR agonist treatment enhanced the expression and secretion of vascular endothelial growth factor in EPCs. LXR agonists accelerated re-endothelialization in injured mouse carotid arteries in vivo. These data confirm that LXR activation may improve EPC function and endothelial regeneration and repair after vascular injury by activating the PI3K/Akt/eNOS pathway. We conclude that LXRs may be attractive targets for drug development in the treatment of cardiovascular diseases associated with vascular injury. Show less
Liver X receptors (LXRs)-mediated signals in acanthoic acid (AA) ameliorating liver fibrosis were examined in carbon tetrachloride (CCl4)-induced mice and TGF-β stimulated hepatic stellate cells (HSCs Show more
Liver X receptors (LXRs)-mediated signals in acanthoic acid (AA) ameliorating liver fibrosis were examined in carbon tetrachloride (CCl4)-induced mice and TGF-β stimulated hepatic stellate cells (HSCs). AA was isolated from the root of Acanthopanax koreanum Nakai (Araliaceae). CCl4-treated mice were intraperitoneally injected with 10% CCl4 in olive oil (2 mL/kg for 8 weeks). In AA treated groups, mice were intragastrically administrated with AA (20 mg/kg or 50 mg/kg) 3 times per week for 8 weeks. Administration of AA reduced serum aminotransferase and tissue necrosis factor-α (TNF-α) levels evoked by CCl4, and the reverse of liver damage was further confirmed by histopathological staining. Administration of AA reduced the expression of fibrosis markers and regulated the ratio of MMP-13/TIMP-1, further reversed the development of liver fibrosis. TGF-β (5 ng/ml) was added to activate HSC-T6 cells for 2 h, and then treated with AA (1, 3, or 10 μmol/l) for 24 h before analysis. Cells were collected and proteins were extracted to detect the expressions of LXRs. AA could inhibit the expression of α-SMA stimulated by TGF-β and increase the expression of LXRβ. In vivo and in vitro experiments, AA could modulate liver fibrosis induced by CCl4-treatment via activation of LXRα and LXRβ, while inhibit HSCs activation only via activation of LXRβ. Acanthoic acid might ameliorate liver fibrosis induced by CCl4 via LXRs signals. Show less
Transcriptional coregulators are important components of nuclear receptor (NR) signaling machinery and provide additional mechanisms for modulation of NR activity. Expression of a mutated nuclear core Show more
Transcriptional coregulators are important components of nuclear receptor (NR) signaling machinery and provide additional mechanisms for modulation of NR activity. Expression of a mutated nuclear corepressor 1 (NCoR1) that lacks 2 NR interacting domains (NCoRΔID) in the liver leads to elevated expression of genes regulated by thyroid hormone receptor (TR) and liver X receptor (LXR), both of which control hepatic cholesterol metabolism. Here, we demonstrate that expression of NCoRΔID in mouse liver improves dietary cholesterol tolerance in an LXRα-independent manner. NCoRΔID-associated cholesterol tolerance was primarily due to diminished intestinal cholesterol absorption as the result of changes in the composition and hydrophobicity of the bile salt pool. Alterations of the bile salt pool were mediated by increased expression of genes encoding the bile acid metabolism enzymes CYP27A1 and CYP3A11 as well as canalicular bile salt pump ABCB11. We have determined that these genes are regulated by thyroid hormone and that TRβ1 is recruited to their regulatory regions. Together, these data indicate that interactions between NCoR1 and TR control a specific pathway involved in regulation of cholesterol metabolism and clearance. Show less
To investigate whether a synthetic LXR agonist TO901317 (TO90) ameliorates ocular inflammation in a mouse model of experimental autoimmune uveitis (EAU) and to explore its underlying mechanism. EAU wa Show more
To investigate whether a synthetic LXR agonist TO901317 (TO90) ameliorates ocular inflammation in a mouse model of experimental autoimmune uveitis (EAU) and to explore its underlying mechanism. EAU was induced with subcutaneous injection of IRBP161-180 peptide (SGIPYIISYLHPGNTILHVD) in B10.RIII mice. TO90 (50 mg/kg/d) or vehicle was administrated orally for successive 16 days or 8 days as prevention or effector phase, respectively. The severity of EAU was evaluated with clinical and histological scores. The levels of LXRs, NF-κB subunit p65, and an LXR target gene ABCA1 in the retina were detected with real-time PCR and Western blotting. The expressions of proinflammatory genes, including TNF-α, IL-1β, IL-6, MCP-1, IFN-γ, and IL-17, were detected by real-time PCR. IRBP-specific lymphocyte proliferation was detected by MTT. Intracellular IFN-γ and IL-17 in CD4(+) T cells were measured by flow cytometry. We found both LXRα and LXRβ were expressed in mouse retina. After administering TO90 orally to B10.RIII mice, the expression of LXRα but not LXRβ was upregulated in the naïve mice. Compared with naïve mice, LXRα expression was increased in vehicle and TO90-treated EAU mice, but the LXRβ expression was unchanged. The protein level of ABCA1 was enhanced in TO90-treated naïve and EAU mice but was unchanged in vehicle-treated EAU mice, suggesting activation of LXRα by TO90 is ligand dependent. TO90-mediated activation of LXRα improved the clinical and morphological scores in EAU mice. Meanwhile, activation of LXRα decreased the expressions of proinflammatory cytokines, including TNF-α, IL-1β, IL-6, MCP-1, IFN-γ, and IL-17 in the retina. TO90 treatment inhibited IRBP-specific immune responses. The proportions of Th1 and Th17 expressing IFN-γ and IL-17 were reduced in TO90-treated EAU mice in both prevention and effector phases. Furthermore, TO90 significantly downregulated the expressions of an NF-κB subunit p65 at the protein and mRNA levels. TO90 activates LXRα and potently attenuates ocular inflammation in EAU. Alleviation of ocular inflammation could partially result from inhibition of the NF-κB signaling pathway. TO90 reduces IFN-γ and IL-17 expression in both prevention and treatment scenarios. Our data suggest that the LXR agonist may become a novel class of therapeutic agent for autoimmune uveitis. Show less
The objective of this study was to determine the effects of pentraxin3 (PTX3) on human oxidized low density lipoprotein (oxLDL) uptake and cholesterol efflux from human macrophage foam cells, which ma Show more
The objective of this study was to determine the effects of pentraxin3 (PTX3) on human oxidized low density lipoprotein (oxLDL) uptake and cholesterol efflux from human macrophage foam cells, which may play a critical role in atherogenesis. The effects of PTX3 on oxLDL uptake and cholesterol efflux were determined after transfection of human THP-1 macrophages with pSG5hPTX3 or PTX3siRNA plasmids. To evaluate the role of specific signaling pathways, human THP-1 cells were pre-treated with inhibitors of the extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), phosphatidylinositide 3-kinases (PI3-K), and p38 mitogen-activated protein kinase (MAPK) pathways (PD98059, LY294002, and SB203580, respectively), and then exposed to oxLDL for the uptake assay or oxLDL and [(3)H]-cholesterol and apolipoprotein A-I (apoA-I) for the cholesterol efflux assay. PTX3 overexpression not only promoted oxLDL uptake but also significantly reduced cholesterol efflux to apoA-I; it also significantly decreased the expression of peroxisome proliferator-activated receptor-γ (PPARγ), liver X receptor alpha (LXRα) and ATP-binding membrane cassette transporter A-1 (ABCA1), which was increased with PTX3 silencing. Furthermore, PTX3 significantly increased p-ERK1/2 levels in THP-1-derived foam cells, and inhibition of ERK1/2 by PD98059 significantly reduced the oxLDL uptake and promoted the cholesterol efflux induced by PTX3 overexpression. Here, we demonstrate that PTX3 affects lipid accumulation in human macrophages, increasing oxLDL uptake and inhibiting cholesterol efflux. That is the underlying possible mechanisms of PTX3 contribution to the progression of atherosclerosis. Show less
Apolipoprotein M (apoM), as a novel apolipoprotein which is mainly expressed in liver and kidney tissues, is associated with development and progression of atherosclerosis and diabetes. Our group have Show more
Apolipoprotein M (apoM), as a novel apolipoprotein which is mainly expressed in liver and kidney tissues, is associated with development and progression of atherosclerosis and diabetes. Our group have recently shown that Dihydrocapsaicin(DHC)can significantly decrease atherosclerotic plaque formation in apoE-/- mice. However, the effect and possible mechanism of DHC on apoM expression remain unclear. HepG2 cells were treated with 0 μM, 25 μM, 50 μM and 100 μM DHC for 24 h or were treated with 100 μM DHC for 0, 6, 12, and 24 h, respectively. The mRNA levels and protein levels were measured by real-time quantitative PCR and western blot analysis, respectively. We found that DHC markedly decreased expression of apoM at both mRNA and protein level in HepG2 cells in a dose-dependent and time-dependent manner. Expression of Foxa2 was decreased while expression of LXRα was increased by DHC treatment in HepG2 cells. In addittion, overexpression of Foxa2 markedly compensated the inhibition effect induced by DHC on apoM expression. LXRα small interfering RNA significantly abolished the inhibition effect which induced by DHC on apoM expression. The liver of C57BL/6 mice treated with DHC had significantly lower expression of apoM. Furthermore, the liver had lower expression of Foxa2 while had higher expression of LXRα. DHC could down-regulate apoM expression through inhibiting Foxa2 expression and enhancing LXRα expression in HepG2 cells. Show less
To explore the relationship between the liver X receptor α gene (LXRα) rsl2221497 polymorphism and the susceptibility of coronary heart disease (CHD) and serum lipids and glucose levels. The single fl Show more
To explore the relationship between the liver X receptor α gene (LXRα) rsl2221497 polymorphism and the susceptibility of coronary heart disease (CHD) and serum lipids and glucose levels. The single fluorescently labeled probes technique was used to detect the genotype of rsl2221497 in LXRα gene in 240 CHD patients and 250 healthy control subjects. The difference of genotype distribution between the two groups was analyzed using of Chi-square test. The serum lipids and glucose levels between the different genotypes were also compared. The risk of CHD in carriers with (AA + GA) genotype was 1.76 times as that in the GG genotype carriers (OR = 1.76, 95% CI: 1.18-2.87, P <0.05), and the risk of CHD in carriers with A allele increased 0.88 times compared to that in G allele carriers (OR = 1.88, 95% CI:1.21-3.43, P <0.01). Logistic regression analysis showed that after adjusting for other confounding factors, A allele was an independent risk for CHD. However, there were no differences in serum lipids and glucose levels between each genotype. The rsl2221497 polymorphism in LXRα gene was associated with susceptibility of CHD in Han population. Show less
LXR (liver X receptor) is a ligand-activated transcription factor and plays an important role in regulation of lipid homoeostasis and inflammation. Several studies indicate that LXR inhibits IFN-γ (in Show more
LXR (liver X receptor) is a ligand-activated transcription factor and plays an important role in regulation of lipid homoeostasis and inflammation. Several studies indicate that LXR inhibits IFN-γ (interferon γ)-induced biological responses; however, the influence of LXR on IFN-γ expression has not been fully elucidated. In the present study, we investigated the effects of LXR activation on IFN-γ expression at different levels. At the molecular level, we surprisingly observed that LXR ligand (T0901317) induced macrophage and T-cell IFN-γ protein expression which was associated with increased mRNA and secreted protein levels in culture medium. In contrast, selective inhibition of LXRα and/or LXRβ expression by siRNA reduced IFN-γ expression. Promoter analysis defined the multiple LXREs (LXR-responsive elements) in the proximal region of the IFN-γ promoter. EMSAs and ChIP indicated that LXR activation enhanced the binding of LXR protein to these LXREs. In vivo, T0901317 increased wild-type mouse serum IFN-γ levels and IFN-γ expression in the lung and lymph nodes. Functionally, we observed that administration of T0901317 to wild-type mice increased rates of survival and being tumour-free, and inhibited tumour growth when the animals were inoculated with LLC1 carcinoma. In contrast, these protective effects were substantially attenuated in IFN-γ-knockout (IFN-γ-/-) mice, suggesting that the induction of IFN-γ production plays a critical role in T0901317-inhibited tumour growth. Taken together, the results of the present study show that IFN-γ is another molecular target of LXR activation, and it suggests a new mechanism by which LXR inhibits tumour growth. Show less
Liver X receptor α (LXRα) plays an important role in reverse cholesterol transport (RCT), and activation of LXRα could reduce atherosclerosis. In the present study, we developed a screening method to Show more
Liver X receptor α (LXRα) plays an important role in reverse cholesterol transport (RCT), and activation of LXRα could reduce atherosclerosis. In the present study, we developed a screening method to identify new potential LXRα agonists using an LXRα-GAL4 chimera reporter assay. A novel analogue of N,N-disubstituted 2,8-diazaspiro[4.5]decane, IMB-151, was identified as an LXRα agonist by using this method. IMB-151 showed a significant activation effect on LXRα, with an EC50 value of 1.47 µM. IMB-151 also increased the expression of ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) in RAW264.7 macrophages. The upregulating effects of IMB-151 on ABCA1 and ABCG1 markedly decreased when coincubated with geranylgeranyl pyrophosphate (GGPP) ammonium salt or LXRα small interfering RNA (siRNA). Our data indicated that the upregulation of ABCA1 and ABCG1 by IMB-151 depended on activation of LXRα. Moreover, IMB-151 significantly reduced cellular lipid accumulation and increased cholesterol efflux in RAW264.7 macrophages. Interestingly, IMB-151 slightly increased sterol response element binding protein 1c (SREBP-1c) protein expression levels in HepG2 cells compared with TO901317, and this indicated that IMB-151 might have less lipogenesis side effect in vivo. These results suggested that IMB-151 was identified as a selective agonist for LXRα by using a screening method and could be used as a potential antiatherosclerotic lead compound in the future. Show less
To evaluate the preventive and therapeutic effects of Lactobacilluscasei Zhang on impaired glucose tolerance (IGT) by using fructose-induced hyperinsulinemia rats. Rats were fed 25 % fructose solution Show more
To evaluate the preventive and therapeutic effects of Lactobacilluscasei Zhang on impaired glucose tolerance (IGT) by using fructose-induced hyperinsulinemia rats. Rats were fed 25 % fructose solution for hyperinsulinemia with L.casei Zhang for prevention or therapy. Serum levels of insulin, glucagon-like peptide-2 (GLP-2), osteocalcin, malondialdehyde (MDA), total intestinal bile acids and hepatic glycogen contents were determined by assay kits. The major bacteria from feces and liver expression of adiponectin receptor 2 (AdipoR2), liver X receptor-α (LXR-α), peroxisome proliferator-activated receptor gamma (PPAR-γ) and vitamin K epoxide reductase complex subunit 1 mRNA were assessed by RT-PCR. Pancreas injury was evaluated by histological analysis. Lactobacilluscasei Zhang significantly increased numbers of Lactobacillus and Bifidobacterium and decreased Clostridium in the intestine (p < 0.01). Meanwhile, liver glycogen contents were significantly decreased (p < 0.05). In preventive group, accompanied by significantly lower insulin and GLP-2 levels (p < 0.05), L.casei Zhang prevented rats from an increase in oral glucose tolerance area under curve (AUC) which was significant in hyperinsulinemia group (p < 0.05). In therapeutic group, L.casei Zhang administration possessed improved glucose tolerance (p < 0.05), which were associated with increased osteocalcin level (p < 0.01), improved intestinal bile acids secretion (p = 0.060), decreased serum MDA levels (p < 0.05) and upregulation of LXR-α, PPAR-γ and AdipoR2 gene expression, as well as an increase in Bacteroides fragilis (p < 0.05). Lactobacilluscasei Zhang administration exert both preventive and ameliorative effect on oral glucose tolerance AUC in IGT rats but may be via different mechanisms. L.casei Zhang could prevent rats from increased AUC through GLP-2 lowering, while the ameliorative effect in high-fructose-fed post-adolescent rats may be via B. fragilis enriched vitamin K2-dependent osteocalcin mechanism in which AdipoR2, LXR-α and PPAR-γ signaling were involved. Show less
Youjun Li, Zhiyi Wei, Yan Yan+3 more · 2014 · Proceedings of the National Academy of Sciences of the United States of America · National Academy of Sciences · added 2026-04-24
The Crumbs (Crb) complex, formed by Crb, PALS1, and PATJ, is evolutionarily conserved in metazoans and acts as a master cell-growth and -polarity regulator at the apical membranes in polarized epithel Show more
The Crumbs (Crb) complex, formed by Crb, PALS1, and PATJ, is evolutionarily conserved in metazoans and acts as a master cell-growth and -polarity regulator at the apical membranes in polarized epithelia. Crb intracellular functions, including its direct binding to PALS1, are mediated by Crb's highly conserved 37-residue cytoplasmic tail. However, the mechanistic basis governing the highly specific Crb-PALS1 complex formation is unclear, as reported interaction between the Crb tail (Crb-CT) and PALS1 PSD-95/DLG/ZO-1 (PDZ) domain is weak and promiscuous. Here we have discovered that the PDZ-Src homolgy 3 (SH3)-Guanylate kinase (GK) tandem of PALS1 binds to Crb-CT with a dissociation constant of 70 nM, which is ∼ 100-fold stronger than the PALS1 PDZ-Crb-CT interaction. The crystal structure of the PALS1 PDZ-SH3-GK-Crb-CT complex reveals that PDZ-SH3-GK forms a structural supramodule with all three domains contributing to the tight binding to Crb. Mutations disrupting the tertiary interactions of the PDZ-SH3-GK supramodule weaken the PALS1-Crb interaction and compromise PALS1-mediated polarity establishment in Madin-Darby canine kidney (MDCK) cysts. We further show that specific target binding of other members of membrane-associated guanylate kinases (MAGUKs) (e.g., CASK binding to neurexin) also requires the presence of their PDZ-SH3-GK tandems. Show less
Autophagy is a multistep process that involves the degradation and digestion of intracellular components by the lysosome. It has been proved that many core autophagy-related molecules participate in t Show more
Autophagy is a multistep process that involves the degradation and digestion of intracellular components by the lysosome. It has been proved that many core autophagy-related molecules participate in this event. However, new component proteins that regulate autophagy are still being discovered. At present, we report PHF23 (PHD finger protein 23) with a PHD-like zinc finger domain that can negatively regulate autophagy. Data from experiments indicated that the overexpression of PHF23 impaired autophagy, as characterized by decreased levels of LC3B-II and weakened degradation of endogenous and exogenous autophagic substrates. Conversely, knockdown of PHF23 resulted in opposite effects. Molecular mechanism studies suggested that PHF23 interacts with LRSAM1, which is an E3 ligase key for ubiquitin-dependent autophagy against invading bacteria. PHF23 promotes the ubiquitination and proteasome degradation of LRSAM1. We also show that the PHD finger of PHF23 is a functional domain needed for the interaction with LRSAM1. Altogether, our results indicate that PHF23 is a negative regulator associated in autophagy via the LRSAM1 signaling pathway. The physical and functional connection between the PHF23 and LRSAM1 needs further investigation. Show less
WASH (Wiskott-Aldrich syndrome protein (WASP) and SCAR homolog) was identified to function in endosomal sorting via Arp2/3 activation. We previously demonstrated that WASH is a new interactor of BECN1 Show more
WASH (Wiskott-Aldrich syndrome protein (WASP) and SCAR homolog) was identified to function in endosomal sorting via Arp2/3 activation. We previously demonstrated that WASH is a new interactor of BECN1 and present in the BECN1-PIK3C3 complex with AMBRA1. The AMBRA1-DDB1-CUL4A complex is an E3 ligase for K63-linked ubiquitination of BECN1, which is required for starvation-induced autophagy. WASH suppresses autophagy by inhibition of BECN1 ubiquitination. However, how AMBRA1 is regulated during autophagy remains elusive. Here, we found that RNF2 associates with AMBRA1 to act as an E3 ligase to ubiquitinate AMBRA1 via K48 linkage. RNF2 mediates ubiquitination of AMBRA1 at lysine 45. Notably, RNF2 deficiency enhances autophagy induction. Upon autophagy induction, RNF2 potentiates AMBRA1 degradation with the help of WASH. WASH deficiency impairs the association of RNF2 with AMBRA1 to impede AMBRA1 degradation. Our findings reveal another novel layer of regulation of autophagy through WASH recruitment of RNF2 for AMBRA1 degradation leading to downregulation of autophagy. Show less