GPCR inhibitors are highly prevalent in modern therapeutics. However, interference with complex GPCR regulatory mechanisms leads to both therapeutic efficacy and adverse effects. Recently, the sphingo Show more
GPCR inhibitors are highly prevalent in modern therapeutics. However, interference with complex GPCR regulatory mechanisms leads to both therapeutic efficacy and adverse effects. Recently, the sphingosine-1-phosphate (S1P) receptor inhibitor FTY720 (also known as Fingolimod), which induces lymphopenia and prevents neuroinflammation, was adopted as a disease-modifying therapeutic in multiple sclerosis. Although highly efficacious, dose-dependent increases in adverse events have tempered its utility. We show here that FTY720P induces phosphorylation of the C-terminal domain of S1P receptor 1 (S1P₁) at multiple sites, resulting in GPCR internalization, polyubiquitinylation, and degradation. We also identified the ubiquitin E3 ligase WWP2 in the GPCR complex and demonstrated its requirement in FTY720-induced receptor degradation. GPCR degradation was not essential for the induction of lymphopenia, but was critical for pulmonary vascular leak in vivo. Prevention of receptor phosphorylation, internalization, and degradation inhibited vascular leak, which suggests that discrete mechanisms of S1P receptor regulation are responsible for the efficacy and adverse events associated with this class of therapeutics. Show less
A-kinase (PKA) anchoring proteins (AKAPs) are essential for targeting type II PKA to specific locales in the cell to control function. In the present study, AKAP5 (formerly AKAP150) and AKAP6 were ide Show more
A-kinase (PKA) anchoring proteins (AKAPs) are essential for targeting type II PKA to specific locales in the cell to control function. In the present study, AKAP5 (formerly AKAP150) and AKAP6 were identified in mouse parotid acini by type II PKA regulatory subunit (RII) overlay assay and Western blot analysis of mouse parotid cellular fractions, and the role of AKAP5 in mouse parotid acinar cell secretion was determined. Mice were euthanized with CO(2). Immunofluorescence staining of acinar cells localized AKAP5 to the basolateral membrane, whereas AKAP6 was associated with the perinuclear region. In functional studies, amylase secretion from acinar cells of AKAP5 mutant [knockout (KO)] mice treated with the beta-adrenergic agonist, isoproterenol, was reduced overall by 30-40% compared with wild-type (WT) mice. In contrast, amylase secretion in response to the adenylyl cyclase (AC) activator, forskolin, and the cAMP-dependent protein kinase (PKA) activator, N(6)-phenyl-cAMP, was not statistically different in acini from WT and AKAP5 KO mice. Treatment of acini with isoproterenol mimicked the effect of the Epac activator, 8-(4-methoxyphenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (8-pMeOPT-2'-O-Me-cAMP), in stimulating Rap1. However, in contrast to isoproterenol, treatment of acini with 8-pMeOPT-2'-O-Me-cAMP resulted in stimulation of amylase secretion from both AKAP5 KO and WT acinar cells. As a scaffolding protein, AKAP5 was found to coimmunoprecipitate with AC6, but not AC8. Data suggest that isoproterenol-stimulated amylase secretion occurs via both an AKAP5/AC6/PKA complex and a PKA-independent, Epac pathway in mouse parotid acini. Show less
Apolipoprotein A-V (apo A-V) exerts a potent triglyceride (TG)-lowering effect through enhanced intravascular TG-hydrolysis with increased uptake of TG-derived free fatty acids into muscle and adipose Show more
Apolipoprotein A-V (apo A-V) exerts a potent triglyceride (TG)-lowering effect through enhanced intravascular TG-hydrolysis with increased uptake of TG-derived free fatty acids into muscle and adipose tissue. Genetic variants in the APOA5 gene were strongly associated with plasma TG concentrations. The aim of this study was to examine whether APOA5 genetic variation was associated with obesity. We genotyped the missense c.553 G>T polymorphism (p.G185C) in the APOA5 gene in 1,085 Chinese (333 obese subjects and 752 nonobese controls). We analyzed the association between the c.553 G>T polymorphism and obesity and related metabolic phenotypes. The T allele at the c.553 G>T polymorphism was associated with higher plasma TG concentrations. Each additional T allele was associated with an increased TG concentration of 53.5 mg/dl (95% confidence interval (CI) 29.6-76.0, P < 0.0001). However, the T allele was associated lower risk of obesity (odds ratio (OR), 0.48; 95% CI 0.32-0.73, P = 0.0004). Each additional copy of the T allele was associated with a BMI decrease of 0.73 kg/m(2) (95% CI 0.26-1.16, P = 0.002), equivalent to 2.11 kg in a person 1.7 m tall. We may then conclude that the TG-raising APOA5 genetic variant was associated with a decrease in BMI and reduced risk of obesity in the Chinese population. Show less
Insulin resistance results in dysregulated hepatic gluconeogenesis that contributes to obesity-related hyperglycemia and progression of type 2 diabetes mellitus (T2DM). Recent studies show that MAPK p Show more
Insulin resistance results in dysregulated hepatic gluconeogenesis that contributes to obesity-related hyperglycemia and progression of type 2 diabetes mellitus (T2DM). Recent studies show that MAPK phosphatase-3 (MKP-3) promotes gluconeogenic gene transcription in hepatoma cells, but little is known about the physiological role of MKP-3 in vivo. Here, we have shown that expression of MKP-3 is markedly increased in the liver of diet-induced obese mice. Consistent with this, adenovirus-mediated MKP-3 overexpression in lean mice promoted gluconeogenesis and increased fasting blood glucose levels. Conversely, shRNA knockdown of MKP-3 in both lean and obese mice resulted in decreased fasting blood glucose levels. In vitro experiments identified forkhead box O1 (FOXO1) as a substrate for MKP-3. MKP-3-mediated dephosphorylation of FOXO1 at Ser256 promoted its nuclear translocation and subsequent recruitment to the promoters of key gluconeogenic genes. In addition, we showed that PPARγ coactivator-1α (PGC-1α) acted downstream of FOXO1 to mediate MKP-3-induced gluconeogenesis. These data indicate that MKP-3 is an important regulator of hepatic gluconeogenesis in vivo and suggest that inhibition of MKP-3 activity may provide new therapies for T2DM. Show less
Most methods used for gene expression analysis are based on dye-labeling, which requires costly instruments. Recently a dye-free gene expression analysis method-SRPP (Sequence-tagged reverse-transcrip Show more
Most methods used for gene expression analysis are based on dye-labeling, which requires costly instruments. Recently a dye-free gene expression analysis method-SRPP (Sequence-tagged reverse-transcription polymerase chain reaction coupled with pyrosequencing) was developed to compare relative gene expression levels in different tissues, but the throughput of the SRPP assay is very limited due to the use of a photomultiplier tube (PMT)-based pyrosequencer for the detection. To increase the throughput of the SRPP assay, an inexpensive photodiode (PD) array-based bioluminescence analyzer (termed as "PD-based pyrosequencer") was coupled to SRPP; however the low sensitivity of PD limited the wide application of SRPP. To enable SRPP analyzing low abundance genes in clinical samples, sequence-tagged gene-specific primers instead of sequence-tagged poly (T)(n) primers were used for reverse-transcription, and the SRPP sensitivity was thus improved more than 10 times. This improvement compensates the sensitivity loss due to the use of PD in a pyrosequencer. The accurate determination of the expression levels of ten prognostic marker genes (AL080059, MMP9, EXT1, ORC6L, AF052162, C9orf30, FBXO31, IGFBP5, ESM1, and RUNDC1) differing between normal tissues and tumor tissues of breast cancer patients demonstrated that SRPP using gene-specific RT primers coupled with the PD array-based bioluminescence analyzer is reliable, inexpensive, and sensitive in gene expression analysis. Show less
Cardiac hypertrophy is a common response to hemodynamic stress in the heart and can progress to heart failure. To investigate whether the transcription factor cardiovascular basic helix-loop-helix fac Show more
Cardiac hypertrophy is a common response to hemodynamic stress in the heart and can progress to heart failure. To investigate whether the transcription factor cardiovascular basic helix-loop-helix factor 1/hairy/enhancer of split related with YRPW motif 2 (CHF1/Hey2) influences the development of cardiac hypertrophy and progression to heart failure under conditions of pressure overload, we performed aortic constriction on 12-wk-old male wild-type (WT) and heterozygous (HET) mice globally underexpressing CHF1/Hey2. After aortic banding, WT and HET mice showed increased cardiac hypertrophy as measured by gravimetric analysis, as expected. CHF1/Hey2 HET mice, however, demonstrated a greater increase in the ventricular weight-to-body weight ratio compared with WT mice (P < 0.05). Echocardiographic measurements showed a significantly decreased ejection fraction compared with WT mice (P < 0.05). Histological examination of Masson trichrome-stained heart tissue demonstrated extensive fibrosis in HET mice compared with WT mice. TUNEL staining demonstrated increased apoptosis in HET hearts (P < 0.05). Exposure of cultured neonatal myocytes from WT and HET mice to H(2)O(2) and tunicamycin, known inducers of apoptosis that work through different mechanisms, demonstrated significantly increased apoptosis in HET cells compared with WT cells (P < 0.05). Expression of Bid, a downstream activator of the mitochondrial death pathway, was expressed in HET hearts at increased levels after aortic banding. Expression of GATA4, a transcriptional activator of cardiac hypertrophy, was also increased in HET hearts, as was phosphorylation of GATA4 at Ser(105). Our findings demonstrate that CHF1/Hey2 expression levels influence hypertrophy and the progression to heart failure in response to pressure overload through modulation of apoptosis and GATA4 activity. Show less
The antagonism of LINGO-1, a CNS-specific negative regulator of neuronal survival, was shown to promote short-term survival of retinal ganglion cell (RGC) in an ocular hypertension model. LINGO-1 anta Show more
The antagonism of LINGO-1, a CNS-specific negative regulator of neuronal survival, was shown to promote short-term survival of retinal ganglion cell (RGC) in an ocular hypertension model. LINGO-1 antagonists, combined with brain-derived neurotrophic factor (BDNF), can increase the length of neuron survival through an unclear molecular mechanism. To determine the relationship between LINGO-1 and BDNF/TrkB receptor in neuronal protection, we show here that LINGO-1 forms a receptor complex with TrkB and negatively regulates its activation in the retina after ocular hypertension injury. LINGO-1 antagonist antibody 1A7 or soluble LINGO-1 (LINGO-1-Fc) treatment upregulates phospho-TrkB phosphorylation and leads to RGC survival after high intraocular pressure injury. This neuronal protective effect was blocked by anti-BDNF antibody. LINGO-1 antagonism therefore promotes RGC survival by regulating the BDNF and TrkB signaling pathway after ocular hypertension. Show less
Upregulation of endothelin 1 (ET-1) causing blood flow alteration and increased extracellular matrix production are characteristic features of diabetic angiopathy. Several glucose-induced signaling me Show more
Upregulation of endothelin 1 (ET-1) causing blood flow alteration and increased extracellular matrix production are characteristic features of diabetic angiopathy. Several glucose-induced signaling mechanisms cause ET-1 upregulation in diabetic angiopathy. Extracellular signal-regulated kinase 5 (ERK5) is a member of the MAPK family, which plays a key role in cardiovascular development. ERK kinase (MEK) 5 is the specific MEK for ERK5 activation. In this study we examined the role of glucose-induced ERK5 signaling in mediating ET-1 expression in diabetic angiopathy. We investigated retinas from 1-month STZ-induced diabetic rats and human macro- and microvascular endothelial cells to study ERK5-dependent ET-1 alterations. Glucose (25 mmol/L) caused significant upregulation of ET-1 mRNA and downregulation of ERK5 and Kruppel-like factor 2 (KLF2) after 24 h treatment in the endothelial cells. Simultaneously, phospho-ERK5 proteins were reduced. Activation of ERK5 by constitutively active MEK5 (caMEK5) upregulated KLF2 and suppressed ET-1 expression in both cell lines, whereas ERK5 siRNA transfection resulted in decreased ERK5 and KLF2 and increased ET-1 mRNA expression. In addition, caMEK5 prevented glucose-induced upregulation of ET-1. Furthermore, 1 month of diabetes caused a significant increase in retinal ET-1 mRNA and decrease in ERK5 mRNA expression. These data indicate that ERK5 signaling regulates glucose-induced ET-1 expression in diabetes. The ERK5/ET-1 pathway may provide a potential novel target for the treatment of diabetic angiopathy. Show less
For patients with diabetes, insulin resistance and hyperglycemia both contribute to increased serum triglyceride in the form of very low-density lipoprotein (VLDL). Our objective was to define the ins Show more
For patients with diabetes, insulin resistance and hyperglycemia both contribute to increased serum triglyceride in the form of very low-density lipoprotein (VLDL). Our objective was to define the insulin conditions in which hyperglycemia promotes increased serum VLDL in vivo. We performed hyperglycemic-hyperinsulinemic clamp studies and hyperglycemic-hypoinsulinemic clamp studies in rats, with metabolic tracers for glucose flux and de novo fatty acid synthesis. When blood glucose was clamped at hyperglycemia (17 mm) for 2 h under hyperinsulinemic conditions (4 mU/kg . min), serum VLDL levels were not increased compared with baseline. We speculated that hyperinsulinemia minimized glucose-mediated VLDL changes and performed hyperglycemic-hypoinsulinemic clamp studies in which insulin was clamped near fasting levels with somatostatin (17 mm blood glucose, 0.25 mU/kg . min insulin). Under low-insulin conditions, serum VLDL levels were increased 4.7-fold after hyperglycemia, and forkhead box O1 (FoxO1) was not excluded from the nucleus of liver cells. We tested the extent that impaired inactivation of FoxO1 by insulin was sufficient for glucose to promote increased serum VLDL. We found that, when the ability of insulin to inactivate FoxO1 is blocked after adenoviral delivery of constitutively active FoxO1, glucose increased serum VLDL triglyceride when given both by ip glucose tolerance testing (3.5-fold increase) and by a hyperglycemic clamp (4.6-fold). Under both experimental conditions in which insulin signaling to FoxO1 was impaired, we found increased activation of carbohydrate response element binding protein. These data suggest that glucose more potently promotes increased serum VLDL when insulin action is impaired, with either low insulin levels or disrupted downstream signaling to the transcription factor FoxO1. Show less
We have previously shown that mouse atherosclerosis regression involves monocyte-derived (CD68+) cell emigration from plaques and is dependent on the chemokine receptor CCR7. Concurrent with regressio Show more
We have previously shown that mouse atherosclerosis regression involves monocyte-derived (CD68+) cell emigration from plaques and is dependent on the chemokine receptor CCR7. Concurrent with regression, mRNA levels of the gene encoding LXRalpha are increased in plaque CD68+ cells, suggestive of a functional relationship between LXR and CCR7. To extend these results, atherosclerotic Apoe-/- mice sufficient or deficient in CCR7 were treated with an LXR agonist, resulting in a CCR7-dependent decrease in plaque CD68+ cells. To test the requirement for LXR for CCR7-dependent regression, we transplanted aortic arches from atherosclerotic Apoe-/- mice, or from Apoe-/- mice with BM deficiency of LXRalpha or LXRbeta, into WT recipients. Plaques from both LXRalpha and LXRbeta-deficient Apoe-/- mice exhibited impaired regression. In addition, the CD68+ cells displayed reduced emigration and CCR7 expression. Using an immature DC line, we found that LXR agonist treatment increased Ccr7 mRNA levels. This increase was blunted when LXRalpha and LXRbeta levels were reduced by siRNAs. Moreover, LXR agonist treatment of primary human immature DCs resulted in functionally significant upregulation of CCR7. We conclude that LXR is required for maximal effects on plaque CD68+ cell expression of CCR7 and monocyte-derived cell egress during atherosclerosis regression in mice. Show less
Kenichi Matsushita, Fulvio Morello, Yaojiong Wu+4 more · 2010 · The Journal of biological chemistry · American Society for Biochemistry and Molecular Biology · added 2026-04-24
Renin is a key enzyme for cardiovascular and renal homeostasis and is produced by highly specialized endocrine cells in the kidney, known as juxtaglomerular (JG) cells. The nature and origin of these Show more
Renin is a key enzyme for cardiovascular and renal homeostasis and is produced by highly specialized endocrine cells in the kidney, known as juxtaglomerular (JG) cells. The nature and origin of these cells remain as mysteries. Previously, we have shown that the nuclear hormone receptor liver X receptor-alpha (LXRalpha) is a major transcriptional regulator of the expression of renin, c-myc, and other genes involved with growth/differentiation. In this study we test the hypothesis that LXRalpha plays an important role not only in renin expression but also in renin-containing cell differentiation, specifically from the mesenchymal stem cell (MSC), which may be the origin of the JG cell. Indeed, our data demonstrated that LXRalpha activation by its ligands or cAMP stimulated renin gene expression in both murine and human MSCs. Furthermore, sustained cAMP stimulation of murine MSCs overexpressing LXRalpha led to their differentiation into JG-like cells expressing renin and alpha-smooth muscle actin. These MSC-derived JG-like cells contained renin in secretory granules and released active renin in response to cAMP. In conclusion, the activation of LXRalpha stimulates renin expression and induces MSCs differentiation into renin-secreting, JG-like cells. Our results suggest that the MSC may be the origin of the juxtaglomerular cell and provide insight into novel understanding of pathophysiology of the renin-angiotensin system. Show less
Cell polarity proteins regulate tight junction formation and directional migration in epithelial cells. To date, the mechanism by which these polarity proteins assemble at the leading edge of migratin Show more
Cell polarity proteins regulate tight junction formation and directional migration in epithelial cells. To date, the mechanism by which these polarity proteins assemble at the leading edge of migrating epithelial cells remains unclear. We report that occludin, a transmembrane protein, is localized at the leading edge of migrating cells and regulates directional cell migration. During migration, occludin knockdown disrupted accumulation of aPKC-Par3 and PATJ at the leading edge, and led to a disorganized microtubule network and defective reorientation of the microtubule organization center (MTOC). Phosphorylation of occludin at tyrosine 473 residue allowed recruitment of p85 alpha to the leading edge via association with its C-terminal SH2 domain. Loss of occludin attenuated activation of PI3K, leading to disorganization of the actin cytoskeleton and reduced cell protrusions. Our data indicate that occludin is required for the leading-edge localization of polarity proteins aPKC-Par3 and PATJ and promotes cell protrusion by regulating membrane-localized activation of PI3K. Show less
Ying Gao, Ke Wu, Yi Xu+9 more · 2009 · Journal of Huazhong University of Science and Technology. Medical sciences = Hua zhong ke ji da xue xue bao. Yi xue Ying De wen ban = Huazhong keji daxue xuebao. Yixue Yingdewen ban · Springer · added 2026-04-24
To identify acute renal allograft rejection biomarkers in human serum, two-dimensional differential in-gel electrophoresis (2-D DIGE) and reversed phase high-performance liquid chromatography (RP-HPLC Show more
To identify acute renal allograft rejection biomarkers in human serum, two-dimensional differential in-gel electrophoresis (2-D DIGE) and reversed phase high-performance liquid chromatography (RP-HPLC) followed by electrospray ionization mass spectrometry (ESI-MS) were used. Serum samples from renal allograft patients and normal volunteers were divided into three groups: acute rejection (AR), stable renal function (SRF) and normal volunteer (N). Serum samples were firstly processed using Multiple Affinity Removal Column to selectively remove the highest abundance proteins. Differentially expressed proteins were analyzed using 2-D DIGE. These differential protein spots were excised, digested by trypsin, and identified by RP-HPLC-ESI/MS. Twenty-two differentially expressed proteins were identified in serum from AR group. These proteins included complement C9 precursor, apolipoprotein A-IV precursor, vitamin D-binding protein precursor, beta-2-glycoprotein 1 precursor, etc. Vitamin D-binding protein, one of these proteins, was confirmed by ELISA in the independent set of serum samples. In conclusion, the differentially expressed proteins as serum biomarker candidates may provide the basis of acute rejection noninvasive diagnosis. Confirmed vitamin D-binding protein may be one of serum biomarkers of acute rejection. Furthermore, it may provide great insights into understanding the mechanisms and potential treatment strategy of acute rejection. Show less
Sui-Yuan Chang, Wei-Shin Ko, Jau-Tsuen Kao+13 more · 2009 · Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · added 2026-04-24
We investigated the relationship between hypertriglyceridemia and the single-nucleotide polymorphisms (SNPs) on APOA5 in human immunodeficiency virus (HIV)-infected patients receiving highly active an Show more
We investigated the relationship between hypertriglyceridemia and the single-nucleotide polymorphisms (SNPs) on APOA5 in human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) in Taiwan. Receipt of protease inhibitor-based HAART, high baseline triglyceride levels, and carriage of APOA5 SNP3 or c.553G>T variants or APOA5 SNP1T/SNP2G/SNP3C/c.553T haplotype were statistically significantly associated with development of extreme hypertriglyceridemia (triglyceride level, >500 mg/dL). Show less
Two groups of Chinese hypertriacylglycerolemic subjects were recruited and randomized to medium- and long-chain triacylglycerols (MLCT) oil or long-chain triacylglycerols (LCT) oil. Two subgroups were Show more
Two groups of Chinese hypertriacylglycerolemic subjects were recruited and randomized to medium- and long-chain triacylglycerols (MLCT) oil or long-chain triacylglycerols (LCT) oil. Two subgroups were divided by age at less or more 60 years in both groups. Both oils were consumed at 25-30 g daily for 8 weeks. Anthropometry, blood biochemicals, and computed tomography (CT) scanning were done at the initial and final times. In subjects of age less than 60 years on MLCT, the body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-hip ratio (WHR), body fat, total fat area, and subcutaneous fat area were significantly lower than those of the initial values, and the change values in these indicators and visceral fat area lowered significantly as compared with those on LCT. The levels of apoB, apoA2, apoC2, and apoC3 decreased significantly, and the change in values in the levels of triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), apoA1, apoB, apoA2, apoC2, apoC3 were significantly lower on MLCT of age under 60 years as compared with those on LCT. Show less
CK2 is a regulatory kinase implicated in embryonic development and in cancer. Among the CK2 substrates is beta-catenin, a protein with dual function in Wnt signaling and cell adhesion. Previously, we Show more
CK2 is a regulatory kinase implicated in embryonic development and in cancer. Among the CK2 substrates is beta-catenin, a protein with dual function in Wnt signaling and cell adhesion. Previously, we reported that CK2 activity is required for beta-catenin stability and we identified threonine (T) 393 as a major CK2 phosphorylation site in beta-catenin. However, it is not known whether phosphorylation at T393 increases beta-catenin stability and if so, what is the mechanism. In this study we investigate the molecular mechanism of beta-catenin stabilization through phosphorylation at T393. We found that pseudophosphorylation of beta-catenin at T393 resulted in a stable activated form of beta-catenin with decreased affinity for Axin in vitro. This phosphomimetic mutant also displayed decreased regulation by Axin in vivo in a bioassay in Xenopus laevis embryos. In contrast, the binding of T393 pseudophosphorylated beta-catenin to E-cadherin was unaffected. Further analysis showed that pseudophosphorylation at T393 did not prevent beta-catenin phosphorylation by GSK3beta. Interestingly, we found that in the presence of pseudophophorylated beta-catenin and another activated form of beta-catenin, the recruitment of GSK3beta to Axin is enhanced. These findings indicate that phosphorylation of T393 by CK2 may affect the stability of beta-catenin through decreased binding to Axin. In addition, the increased recruitment of GSK3beta to the destruction complex in the presence of activated beta-catenin mutants could be a feedback mechanism to suppress overactive Wnt signaling. Show less
Juvenile neuronal ceroid lipofuscinosis (JNCL) is one type of the neuronal ceroid lipofuscinosis (NCLs), which is a group of pediatric neurodegenerative disorders. The symptoms of JNCL are retinal deg Show more
Juvenile neuronal ceroid lipofuscinosis (JNCL) is one type of the neuronal ceroid lipofuscinosis (NCLs), which is a group of pediatric neurodegenerative disorders. The symptoms of JNCL are retinal degeneration (rd), seizures, cognitive, and motor decline. The pathogenesis, summarized in this review, include apoptosis, autophagy, dysfunction in the structure associated with plasmalemma, oxidative stress and disruption of nitric oxide signaling, dysfunction of the mitochondrial and lysosome, unbalanced intracellular pH, and other relative mechanisms. Among them, only apoptosis and autophagy are well known. In apoptosis, the defects in CLN3 result in ceramide accumulation and upstream of mitochondrial membrane per-meabilization, which eventually induce caspase-dependent and caspase-independent cell death. Autophagy exists but is disrupted because the immaturity of autophagic vacuoles leads to the failure of autophagy circulation. Understanding of the pathogenesis, especially the pathways of cell death in JNCL, is helpful to explore the mechanism of neurodegenerative dis-orders, such as JNCL. Show less
Glaucoma is a progressive neuropathy characterized by loss of vision as a result of retinal ganglion cell (RGC) death. There are no effective neuroprotectants to treat this disorder. Brain-derived neu Show more
Glaucoma is a progressive neuropathy characterized by loss of vision as a result of retinal ganglion cell (RGC) death. There are no effective neuroprotectants to treat this disorder. Brain-derived neurotrophic factor (BDNF) is well known to transiently delay RGC death in ocular hypertensive eyes. The CNS-specific leucine-rich repeat protein LINGO-1 contributes to the negative regulation to some trophic pathways. We thereby examined whether BDNF combined with LINGO-1 antagonists can promote long-term RGC survival after ocular hypertension. In this study, intraocular pressure was elevated in adult rats using an argon laser to photocoagulate the episcleral and limbal veins. BDNF alone shows slight neuroprotection to RGCs after a long-term progress of 4 weeks following the induction of ocular hypertension. However, combination of BDNF and LINGO-1-Fc prevents RGC death in the same condition. We further identified that (1) LINGO-1 was co-expressed with BDNF receptor, TrkB in the RGCs, and (2) BDNF combined with LINGO-1-Fc activated more TrkB in the injured retina compared to BDNF alone. These results indicate that the combination of BDNF with LINGO-1 antagonist can provide long-term protection for RGCs in a chronic ocular hypertension model. TrkB may be the predominant mediator of this neuroprotection. Show less
Repair of demyelinated axons in diseases such as multiple sclerosis requires activation of the myelination program in existing or newly recruited oligodendrocyte precursor cells (OPCs). The control of Show more
Repair of demyelinated axons in diseases such as multiple sclerosis requires activation of the myelination program in existing or newly recruited oligodendrocyte precursor cells (OPCs). The control of OPC differentiation and initiation of myelination during repair is poorly understood. In this study, we test the ability of anti-LINGO-1 reagents to promote myelination in vitro and remyelination in the rodent adult central nervous system in vivo. The effects of LINGO-1 antagonists on the differentiation of OPCs and the promotion of myelination has been assayed using a combination of coculture and slice culture preparations. Using three different animal models of demyelination and remyelination, we morphologically and functionally assessed the effects of LINGO-1 antagonists on OPC differentiation and myelin repair. The data indicate that in vitro treatment with antagonists of LINGO-1 promote OPC differentiation and myelination, whereas in vivo remyelination is accelerated in lysophosphatidylcholine- or cuprizone-induced demyelination. This remyelination is associated with enhanced OPC differentiation and functional recovery of conduction velocities in demyelinated axons. Our studies demonstrate that LINGO-1 antagonism promotes OPC differentiation and remyelination, and suggest LINGO-1 functions as an inhibitor of OPC differentiation to retard central nervous system remyelination. Show less
Advances in genomics and proteomics have generated the needs for the efficient identification of key residues for structure and function of target proteins. Here we report the utilization of a new res Show more
Advances in genomics and proteomics have generated the needs for the efficient identification of key residues for structure and function of target proteins. Here we report the utilization of a new residue-screening approach, which combines a mammalian high-throughput transient expression system with a PCR-based expression cassette, for the study of the post-translational modification. Applying this approach results in a quick identification of essential N-glycosylation sites of a heavily glycosylated neuroglycoprotein Lingo-1, which are sufficient for the support of its surface expression. These key N-glycosylated sites uniquely locate on the concave surface of the elongated arc-shape structure of the leucine-rich repeat domain. The swift residue-screening approach may provide a new strategy for structural and functional analysis. Show less
Ming Huo, Hui-ling Zang, Dong-juan Zhang+7 more · 2009 · Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences · added 2026-04-24
To study the role of the carbohydrate response element binding protein (ChREBP) in excessive lipid deposition in the liver of db/db mouse. The deposition of neutral lipids in the liver was evaluated b Show more
To study the role of the carbohydrate response element binding protein (ChREBP) in excessive lipid deposition in the liver of db/db mouse. The deposition of neutral lipids in the liver was evaluated by Oil Red O staining. Immunohistochemical assay was utilized to determine the localization of ChREBP protein expression in mouse liver. The expressions of ChREBP and its target genes including acetyl-coenzyme A carboxylase 1 (Acc-1), fatty acid synthase (Fas), glycerol-3-phosphate acyltransferase (Gpat) were analyzed by Real-time PCR and Western blot. Significant lipid droplet deposition was detected in the livers of db/db mice. ChREBP was diffusely expressed in heptocytes with relative higher expression levels around portal and central veins. ChREBP was predominantly located in the cytosol in non-diabetic db/m mice, but was translocated to the nucleus in db/db mice. Nuclear ChREBP protein levels were 8.2-fold higher in db/db mice than in db/m mice(P<0.01). In contrast, another lipogenic transcription factor, sterol regulatory element binding protein-1(SREBP-1), remained unchanged. Consistent with increased nuclear ChREBP levels, expressions of ChREBP target genes involved in lipogenesis including Acc-1, Fas and Gpat were upregulated by 2-fold(P<0.05),1.7-fold (P<0.05) and 4.2-fold(P<0.05), respectively, in db/db mice. The db/db mouse exhibits significantly higher liver ChREBP activity, which may be associated with the development of hepatic steatosis frequently occurring in type 2 diabetes. Targeting ChREBP might represent a new intervention strategy for fatty liver. Show less
Jie Chen, Rui-Dan Zheng, Chen-Run Xu+1 more · 2009 · Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology · added 2026-04-24
Preparing rat model of non-alcoholic fatty liver disease by fat-rich diet to observe the expression and the role of LXR-alpha in rat nonalcoholic fatty liver disease. Thirty-six SD rats were randonmiz Show more
Preparing rat model of non-alcoholic fatty liver disease by fat-rich diet to observe the expression and the role of LXR-alpha in rat nonalcoholic fatty liver disease. Thirty-six SD rats were randonmized into basic diet-control group and high-fat diet group. Each of the two groups was subdivided into 3 subgroups (4, 8, 12 weeks). Changes in animal weight, liver exponent and the level of TG and TC in serum and liver were observed dynamically. Meanwhile,the expression of hepatocyte LXR-alpha and SREBP-1c were assayed by Reverse transcript-polymerase chain reaction at 4, 8, 12 weeks. The level of steatosis was observed under light microscope after haematoxylon-eosin (HE) staening. Compared with control group, body weight, liver exponent, TG and Tc in serum and liver were increased dynamically in model groups. Compared with control group, the mRNA of LXR-a and SREBP-1c were obviously increased dynamically in model groups (P < 0.05) . The increase of LXR-alpha and SREBP-1c in liver may be concered with energy disorder and closely associated with the activity of inflammation and the severity of the liver damage in NAFLD rats. Show less
The mechanism by which niacin increases plasma levels of high-density lipoprotein cholesterol (HDL-C) is not clearly understood yet. Adipocytes contain the largest pool of free cholesterol in the body Show more
The mechanism by which niacin increases plasma levels of high-density lipoprotein cholesterol (HDL-C) is not clearly understood yet. Adipocytes contain the largest pool of free cholesterol in the body and might play a significant role in cholesterol metabolism. Despite preferential accumulation in adipose tissue, it is not clear whether the actions of niacin on cholesterol efflux from adipocytes contribute to its HDL-raising effect. Fully differentiated 3T3-L1 adipocytes were incubated in the medium containing various concentrations of niacin (0-1.0 mmol/l) for 24 h. Reverse transcription polymerase chain reaction was used to evaluate peroxisome proliferator-activated receptor-gamma (PPARgamma), LXRalpha and ABCA1 mRNA expression in adipocytes. Cholesterol efflux rate was determined by measuring the release of radioactivity from (3)H-cholesterolprelabeled cells into medium containing apolipoprotein A-I (ApoA-I). Niacin dose-dependently stimulated PPARgamma, LXRalpha and ABCA1 mRNA expression and promoted ApoA-I-induced cholesterol efflux in adipocytes. Treatment of PPARgamma-selective antagonist GW9662 significantly abolished the niacin-induced increase in LXRalpha and ABCA1 mRNA expression and cholesterol efflux to ApoA-I. Niacin may promote cholesterol efflux from adipocytes to ApoA-I via activation of the PPARgamma-LXRalpha-ABCA1 pathway. To some extent, this effect might help to explain the possible mechanism by which niacin increases plasma HDL-C levels. Show less
Nuclear factor-kappaB (NF-kappaB) plays a critical role in cell growth and inflammation during the progression of cardiac hypertrophy and heart failure. Several members of nuclear receptor superfamily Show more
Nuclear factor-kappaB (NF-kappaB) plays a critical role in cell growth and inflammation during the progression of cardiac hypertrophy and heart failure. Several members of nuclear receptor superfamily, including liver X receptors (LXRalpha and LXRbeta), have been shown to suppress inflammatory responses, but little is known about their effects in cardiomyocytes. We investigated LXR expression patterns in pressure overload-induced hypertrophic hearts and the hypertrophic growth of the LXRalpha-deficient hearts from mice (C57/B6) in response to pressure overload. The underlying mechanisms were also explored using cultured myocytes. We found that cardiac expression of LXRalpha was upregulated in pressure overload-induced left ventricular hypertrophy in mice. Transverse aorta coarctation-induced left ventricular hypertrophy was exacerbated in LXRalpha-null mice relative to control mice. A synthetic LXR ligand, T1317, suppressed cardiomyocyte hypertrophy in response to angiotensin II and lipopolysaccharide treatments. In addition, LXR activation suppressed NF-kappaB signalling and the expression of associated inflammatory factors. Overexpression of constitutively active LXRalpha and beta in cultured myocytes suppressed NF-kappaB activity. LXRs are negative regulators of cardiac growth and inflammation via suppressing NF-kappaB signalling in cardiomyocytes. This should provide new insights into novel therapeutic targets for treating cardiac hypertrophy and heart failure. Show less
Ming You, Daolong Wang, Pengyuan Liu+39 more · 2009 · Clinical cancer research : an official journal of the American Association for Cancer Research · added 2026-04-24
We have previously mapped a major susceptibility locus influencing familial lung cancer risk to chromosome 6q23-25. However, the causal gene at this locus remains undetermined. In this study, we furth Show more
We have previously mapped a major susceptibility locus influencing familial lung cancer risk to chromosome 6q23-25. However, the causal gene at this locus remains undetermined. In this study, we further refined this locus to identify a single candidate gene, by fine mapping using microsatellite markers and association studies using high-density single nucleotide polymorphisms (SNP). Six multigenerational families with five or more affected members were chosen for fine-mapping the 6q linkage region using microsatellite markers. For association mapping, we genotyped 24 6q-linked cases and 72 unrelated noncancer controls from the Genetic Epidemiology of Lung Cancer Consortium resources using the Affymetrix 500K chipset. Significant associations were validated in two independent familial lung cancer populations: 226 familial lung cases and 313 controls from the Genetic Epidemiology of Lung Cancer Consortium, and 154 familial cases and 325 controls from Mayo Clinic. Each familial case was chosen from one high-risk lung cancer family that has three or more affected members. A region-wide scan across 6q23-25 found significant association between lung cancer susceptibility and three single nucleotide polymorphisms in the first intron of the RGS17 gene. This association was further confirmed in two independent familial lung cancer populations. By quantitative real-time PCR analysis of matched tumor and normal human tissues, we found that RGS17 transcript accumulation is highly and consistently increased in sporadic lung cancers. Human lung tumor cell proliferation and tumorigenesis in nude mice are inhibited upon knockdown of RGS17 levels. RGS17 is a major candidate for the familial lung cancer susceptibility locus on chromosome 6q23-25. Show less
Osteonecrosis of the femoral head (ONFH) is a skeletal disorder characterized by ischemic deterioration, bone marrow edema and eventually femoral head collapse. The systemic regulation of ONFH in adul Show more
Osteonecrosis of the femoral head (ONFH) is a skeletal disorder characterized by ischemic deterioration, bone marrow edema and eventually femoral head collapse. The systemic regulation of ONFH in adult patients has not been examined. Serum proteomic is an innovative tool that potentially detects simultaneous expressions of serum proteins in pathological contexts. We compared the serum proteome profiles of 11 adult patients with ONFH (3 females and 8 males) and 11 healthy volunteers (3 females and 8 males). The proteins in the aliquots of sera were subjected to isoelectric focusing, two-dimensional gel electrophoresis and silver staining. The protein spots were matched and quantified using an imaging analysis system. The differentially expressed protein spots were subjected to in-gel trypsin digestion. The peptide mass fingerprints were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF) and a bioinformation search. We found that ONFH patients showed significantly higher abundances of kininogen 1 variant, complement factor C3 precursor, and complement factor H and lower levels of antithrombin III chain B, apolipoprotein A--IV precursor, and gelsolin isoform alpha precursor. These proteins of interest were reported to modulate thrombotic/fibrinolytic reactions, oxidative stress, vessel injury, tissue necrosis or cell apoptosis in several tissue types under pathological contexts. Taken together, the occurrence of ONFH was associated with various serum protein expressions. Our high--throughput serum proteomic findings indicated that multiple pathological reactions presumably occurred in ONFH. Show less
The -1131T>C polymorphism in the apolipoprotein gene A5 (APOA5) was found to be associated with increased levels of plasma triglyceride and decreased levels of high-density lipoprotein cholesterol (HD Show more
The -1131T>C polymorphism in the apolipoprotein gene A5 (APOA5) was found to be associated with increased levels of plasma triglyceride and decreased levels of high-density lipoprotein cholesterol (HDL-C), which are characteristic dyslipidemic components of metabolic syndrome. This study aimed to identify a link between this polymorphism and the risk of metabolic syndrome. The sample population comprised 615 unrelated subjects, 18.7% of whom had metabolic syndrome. Genotypes were determined via polymerase chain reaction, restriction mapping with MseI, and gel electrophoresis. A significantly higher level of triglycerides and a lower level of HDL-C were noted in carriers of the -1131C allele than in the non-carriers (p<0.001 and p=0.044, respectively). The frequency of the -1131C allele in the metabolic syndrome-affected subjects was significantly higher than that of the group of unaffected subjects (37.4% vs. 27.7%, p=0.004). Even after adjusting for age, gender, smoking, regular exercise, and waist-to-hip ratio, the APOA5 -1131C allele carriers remained significantly associated with an increased risk of metabolic syndrome (OR=1.77, 95% CI, 1.13-2.77; p=0.012). These results indicate that the association of APOA5 -1131T>C polymorphism with dyslipidemia can also contribute to an increased susceptibility to metabolic syndrome in the Chinese, as a result of its effect on triglyceride metabolism. Show less
Seven single nucleotide polymorphisms (SNPs) were identified by PCR-SSCP and sequencing in the chicken apoA5 gene in F2 chickens from an experimental cross of White Plymouth Rock x Silkies. One SNP(C- Show more
Seven single nucleotide polymorphisms (SNPs) were identified by PCR-SSCP and sequencing in the chicken apoA5 gene in F2 chickens from an experimental cross of White Plymouth Rock x Silkies. One SNP(C-169T) located on the 5'-regulatory region, another two in the second exon were transitions of C to T (600) and T to C (635). Four SNPs in the third exon were found, which were C841G, C914T, C1142G, C1394T. The association of the polymorphisms with carcass traits was investigated. The most significant results were yielded from primer apoA3F/R: the abdominal fat weight of CC chickens were significantly higher than that of AA, AB, AC, BB and BC chickens (P<0.05); AC chickens had lower liver weight than that of AA, AB, BB, BC and CC (P<0.05); BC chickens had lower heart weight than that of BB (P<0.05). Show less
Apolipoprotein A5 gene (APOA5) has been shown to modulate plasma triglyceride concentrations. We investigated 2 distinct APOA1/C3/A5 haplotypes roles for hypertriglyceridemia. We recruited 308 cases o Show more
Apolipoprotein A5 gene (APOA5) has been shown to modulate plasma triglyceride concentrations. We investigated 2 distinct APOA1/C3/A5 haplotypes roles for hypertriglyceridemia. We recruited 308 cases of hypertriglyceridemia and 281 normal controls from a hospital. Twelve single nucleotide polymorphisms (SNPs) across the APOA1/C3/A5 gene region were genotyped. One haplotype containing the minor alleles of the APOA5 (-1131T>C, c.553G>T) and APOA1 (-3013C>T,-75G>A) was more prevalent in cases than in controls (11.3% vs. 1.1%, respectively) and was statistically significantly associated with high triglycerides (adjusted odds ratio: 12.83, 95% confidence interval [CI]: 5.1-32.4, P<0.001). Another haplotype that was associated with hypertriglyceridemia (adjusted odds ratio 2.13, 95% CI, 1.37-3.29, P=0.001). Participants carrying both minor alleles of APOA5-1131CC and c.553TT had a 116% higher triglyceride concentration compared with those carrying common allele. The APOA1/C3/A5 haplotype represents an important locus for predicting risk of hypertriglyceridemia among Taiwanese. Show less
Intermittent administration of PTH stimulates bone formation, but the precise mechanisms responsible for PTH responses in osteoblasts are only incompletely understood. Here we show that binding of PTH Show more
Intermittent administration of PTH stimulates bone formation, but the precise mechanisms responsible for PTH responses in osteoblasts are only incompletely understood. Here we show that binding of PTH to its receptor PTH1R induced association of LRP6, a coreceptor of Wnt, with PTH1R. The formation of the ternary complex containing PTH, PTH1R, and LRP6 promoted rapid phosphorylation of LRP6, which resulted in the recruitment of axin to LRP6, and stabilization of beta-catenin. Activation of PKA is essential for PTH-induced beta-catenin stabilization, but not for Wnt signaling. In vivo studies confirmed that PTH treatment led to phosphorylation of LRP6 and an increase in amount of beta-catenin in osteoblasts with a concurrent increase in bone formation in rat. Thus, LRP6 coreceptor is a key element of the PTH signaling that regulates osteoblast activity. Show less