Nε-(carboxymethyl)lysine promotes lipid uptake of macrophage via cluster of differentiation 36 and receptor for advanced glycation end products

BACKGROUND Advanced glycation end products(AGEs)are diabetic metabolic toxic products that cannot be ignored.Nε-(carboxymethyl)lysine(CML),a component of AGEs,could increase macrophage lipid uptake,promote foam cell formation,and thereby accelerate atherosclerosis.The receptor for AGEs(RAGE)and cluster of differentiation 36(CD36)were the receptors of CML.However,it is still unknown whether RAGE and CD36 play key roles in CML-promoted lipid uptake.AIM Our study aimed to explore the role of RAGE and CD36 in CML-induced macrophage lipid uptake.METHODS In this study,we examined the effect of CML on lipid uptake by Raw264.7 macrophages.After adding 10 mmol/L CML,the lipid accumulation in macrophages was confirmed by oil red O staining.Expression changes of CD36 and RAGE were detected with immunoblotting and quantitative real-time polymerase chain reaction.The interaction between CML with CD36 and RAGE was verified by immunoprecipitation.We synthesized a novel N-succinimidyl-4-18Ffluorobenzoate-CML radioactive probe.Radioactive receptor-ligand binding assays were performed to test the binding affinity between CML with CD36 and RAGE.The effects of blocking CD36 or RAGE on CML-promoting lipid uptake were also detected.RESULTS The study revealed that CML significantly promoted lipid uptake by macrophages.Immunoprecipitation and radioactive receptor-ligand binding assays indicated that CML could specifically bind to both CD36 and RAGE.CML had a higher affinity for CD36 than RAGE.ARG82,ASN71,and THR70 were the potential interacting amino acids that CD36 binds to CML Anti-CD36 and anti-RAGE could block the uptake of CML by macrophages.The lipid uptake promotion effect of CML was significantly attenuated after blocking CD36 or RAGE.CONCLUSION Our results suggest that the binding of CML with CD36 and RAGE promotes macrophage lipid uptake.

Transient receptor potential channel A1 involved in calcitonin gene-related peptide release in neurons

Transient receptor potential channel A1 is one of the important transducers of noxious stimuli in the primary afferents, which may contribute to generation of neurogenic inflammation and hyperalgesia. The present study was designed to investigate if activation of transient receptor potential channel A1 may induce calcitonin gene-related peptide release from the primary afferent neurons. We found that application of allyl isothiocyanate, a transient receptor potential channel A1 activator, caused calcitonin gene-related peptide release from the cultured rat dorsal root ganglion neurons. Knock- down of transient receptor potential channel A1 with an antisense oligodeoxynucleotide prevented calcitonin gene-related peptide release by allyl isothiocyanate application in cultured dorsal root ganglion neurons. Thus, we concluded that transient receptor potential channel A1 activation caused calcitonin gene-related peptide release in sensory neurons.

Correlation of calcitonin gene-related peptide and endothelin receptor A with subarachnoid hemorrhage

Numerous studies have demonstrated that endothelin-1 combines with endothelin receptor A, resulting in intense vasoconstriction. Although calcitonin gene-related peptide （CGRP） suppresses endothelin-1, CGRP and endothelin receptor A exhibit direct biological effects on brain tissue. The present study analyzed CGRP and endothelin receptor A expression following subarachnoid hemorrhage in rabbits using immunohistochemistry. CGRP expression was significant at 5 days after model establishment, and endothelin receptor A expression was significant at 3 days after model induction. The perimeter of the basilar artery was measured to determine the amount of cerebral vasospasm. Analytical results revealed a significantly shortened basilar artery perimeter following subarachnoid hemorrhage. Changes in the basilar artery perimeter were negatively associated with endothelin receptor A expression, but positively correlated with CGRP expression in vessels. These results suggest that following subarachnoid hemorrhage, CGRP and endothelin receptor A expressions dynamically changed in brain vessels and tissues, although these changes were not synchronous. Changes in endothelin receptor A expression exhibited a significant effect on the occurrence and development of delayed cerebral vasospasm and delayed neuronal death, while CGRP relaxed vessels and protected nerves.

Controlling N-methyl-D-aspartate receptor subunit 1 with calcitonin gene related peptide after cerebral ischemic injury

BACKGROUND: Activation of N-methyl-D-aspartate receptor (NMDAR) is a key link of exitotoxicity at the phase of cerebral ischemic injury. Because NMDAR is a main way to mediate internal flow of Ca2+ among glutamic acid receptors, over-excitation can cause neuronal apoptosis. Calcitonin gene related peptide has a strongly biological activity. On one hand, it can protect ischemic neurons through inhibiting the expression of NMDAR1 mRNA; on the other hand, it can play the protective effect through down-regulating the expression of NMDAR1 mRNA by exogenous calcitonin gene related peptide. OBJECTIVE: To observe the expression of NMDAR1 and the regulatory effect of calcitonin gene related peptide on the expression of NMDAR1 mRNA and protein in the cerebral cortex of rats with focal cerebral ischemia/reperfusion (I/R). DESIGN: Randomized controlled animal study. SETTING: China Medical University. MATERIALS: A total of 216 healthy male Wistar rats, general grade, weighing 250-280 g, were selected in this study. Twelve rats were randomly selected to regard as control group; meanwhile, other 204 rats were used to establish middle cerebral artery occlusion/reperfusion (MACO) models. The main reagents were detailed as follows: calcitonin gene related peptide (Sigma Company); calcitonin gene related peptide kit (Boster Company); antibody Ⅰ, Ⅱ and antibody β-actin Ⅰ, Ⅱ of NMDAR1 mRNA and chemiluminescence reagent (Santa Cruz Company, USA). METHODS: The experiment was carried out in the Laboratory of Neurobiology of China Medical University from August 2005 to June 2006. ① Right MCAO models of rats were established to cause focal ischemia and scored based on Zea Longa five-grade scale. If the scores were 1, 2 and 3 after wakefulness, the MACO models were established successfully and involved in the experiment. A total of 120 rats with successful modeling were randomly divided into I/R group and administration group with 60 in each group. All rats in the both groups were observed at five time points, including 6, 12, 24, 48 and 72 hours after reperfusion and after 2-hour ischemia, with 12 experimental animals at each time point. Six rats were prepared for detection of hybridization in situ, and the other 6 were used for Western blotting histochemical detection. Rats in the control group were opened their skin to separate common carotid artery and not treated with line and drugs. In addition, rats in the I/R group were treated with 1 mL saline at 2 hours after focal cerebral ischemia, and then, rats in the administration group were treated with 1 mL (1 g/L) calcitonin gene related peptide at 2 hours after focal cerebral ischemia. ② The expression of NMDAR1 mRNA was detected with hybridization in situ at various time points; moreover, the expression of NMDAR1 protein was measured with Western blotting method at various time points. The results were analyzed with Metamoph imaging analytical system. MAIN OUTCOME MEASURES: The expression of NMDAR1 mRNA and its protein in cortical neurons of rats at various time points. RESULTS: A total of 84 rats were excluded because of non-symptoms, exanimation or death; and then, 132 rats were involved in the final analysis. The expression of NMDAR1 mRNA and its protein in cortical neurons of rats in the control group was 0.205±0.001 and 0.184±0.001, respectively; after I/R, expression of NMDAR1 mRNA and its protein was up-regulated, especially, expression of mRNA at 6, 12, 24, 48 and 72 hours was 0.245±0.003, 0.287±0.004, 0.354±0.008, 0.284±0.002 and 0.217±0.006, respectively; moreover, expression of protein at 6, 12, 24, 48 and 72 hours was 0.222±0.003, 0.261±0.028, 0.311±0.004, 0.259±0.013 and 0.210±0.008, respectively. There was significant difference between the two groups (0.205±0.001, P < 0.01). The expression was up-related in the former 24 hours, reached peak at 24 hours, down-regulated, and decreased to the level of control group at 72 hours. Except 72 hours, the expression of NMDAR1 mRNA and its protein was lower in administration group than that in I/R group at other four time points. In addition, the expression of mRNA at 6, 12, 24, 48 and 72 hours was 0.223±0.005, 0.243±0.001, 0.292±0.002, 0.250±0.003 and 0.213±0.003, respectively; moreover, the expression of protein at 6, 12, 24, 48 and 72 hours was 0.216±0.006, 0.245±0.025, 0.276±0.003, 0.241±0.045 and 0.202±0.013, respectively. There was significant difference at various time points (P < 0.05). CONCLUSION: The expressions of NMDAR1 mRNA and its protein of peripheral cortical neurons are up-related in ischemic area after focal cerebral I/R. Meanwhile, exogenous calcitonin gene related peptide can protect cortical neurons through inhibiting expression of NMDAR1 mRNA and its protein after focal cerebral I/R.

MicroRNA-502-3p regulates GABAergic synapse function in hippocampal neurons

Gamma-aminobutyric acid(GABA)ergic neurons,the most abundant inhibitory neurons in the human brain,have been found to be reduced in many neurological disorders,including Alzheimer's disease and Alzheimer's disease-related dementia.Our previous study identified the upregulation of microRNA-502-3p(miR-502-3p)and downregulation of GABA type A receptor subunitα-1 in Alzheimer's disease synapses.This study investigated a new molecular relationship between miR-502-3p and GABAergic synapse function.In vitro studies were perfo rmed using the mouse hippocampal neuronal cell line HT22 and miR-502-3p agomiRs and antagomiRs.In silico analysis identified multiple binding sites of miR-502-3p at GABA type A receptor subunitα-1 mRNA.Luciferase assay confirmed that miR-502-3p targets the GABA type A receptor subunitα-1 gene and suppresses the luciferase activity.Furthermore,quantitative reve rse transcription-polymerase chain reaction,miRNA in situ hybridization,immunoblotting,and immunostaining analysis confirmed that overexpression of miR-502-3p reduced the GABA type A receptor subunitα-1 level,while suppression of miR-502-3p increased the level of GABA type A receptor subunitα-1 protein.Notably,as a result of the overexpression of miR-502-3p,cell viability was found to be reduced,and the population of necrotic cells was found to be increased.The whole cell patch-clamp analysis of human-GABA receptor A-α1/β3/γ2L human embryonic kidney(HEK)recombinant cell line also showed that overexpression of miR-502-3p reduced the GABA current and overall GABA function,suggesting a negative correlation between miR-502-3p levels and GABAergic synapse function.Additionally,the levels of proteins associated with Alzheimer s disease were high with miR-502-3p overexpression and reduced with miR-502-3p suppression.The present study provides insight into the molecular mechanism of regulation of GABAergic synapses by miR-502-3p.We propose that micro-RNA,in particular miR-502-3p,could be a potential therapeutic to rget to modulate GABAergic synapse function in neurological disorders,including Alzheimer's disease and Alzheimer's diseaserelated dementia.

Cyclooxygenase-2 and epithelial growth factor receptor up-regulation during progression of Barrett's esophagus to adenocarcinoma

AIM： To investigate the expression of cyclooxygenase-2 （COX-2） and epithelial growth factor receptor （EGFR） throughout the progression of Barrett＇s esophagus （BE）. METHODS： COX-2 and EGFR protein expressions were detected by using immunohistochemical method. A detailed cytomorphological changes were determined. Areas of COX-2 and EGFR expression were quantified by using computer Imaging System. RESULTS： The expressions of both COX-2 and EGFR increased along with the progression from BE to esophagus adenocarcinoma （EAC）. A positive correlation was found between COX-2 expression and EGFR expression. CONCLUSION： COX-2 and EGFR may be cooperative in the stepwise progression from BE to EAC, thereby leading to carcinogenesis.

Effects of ω-3 fatty acids on toll-like receptor 4 and nuclear factor-κB p56 in lungs of rats with severe acute pancreatitis

AIM To determine the effects of ω-3 fatty acids(ω-3FA) on the toll-like receptor 4(TLR4)/nuclear factor κB p56(NF-κBp56) signal pathway in the lungs of rats with severe acute pancreatitis(SAP).METHODS A total of 56 Sprague-Dawley rats were randomly divided into 4 groups: control group, SAP-saline group, SAP-soybean oil group and SAP-ω-3FA group. SAP was induced by the retrograde infusion of sodium taurocholate into the pancreatic duct. The expression of TLR4 and NF-κBp56 in the lungs was evaluated by immunohistochemistry and Western blot analysis. The levels of inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha in the lungs were measured by enzyme-linked immunosorbent assay. RESULTS The expression of TLR4 and NF-κBp56 in lungs and of inflammatory cytokines in serum significantly increased in the SAP group compared with the control group(P < 0.05), but was significantly decreased in the ω-3FA group compared with the soybean oil group at 12 and 24 h(P < 0.05).CONCLUSION During the initial stage of SAP, ω-3FA can efficiently lower the inflammatory response and reduce lung injury by triggering the TLR4/NF-κBp56 signal pathway.

Alterations in serotonin, transient receptor potential channels and protease-activated receptors in rats with irritable bowel syndrome attenuated by Shugan decoction

AIM:To determine the molecular mechanisms of Shugan decoction(SGD) in the regulation of colonic motility and visceral hyperalgesia(VHL) in irritable bowel syndrome(IBS).METHODS:The chemical compounds contained in SGD were measured by high-performance liquid chromatography.A rat model of IBS was induced by chronic water avoidance stress(WAS).The number of fecal pellets was counted after WAS and the pain pressure threshold was measured by colorectal distension.Morphological changes in colonic mucosa were detected by hematoxylin-eosin staining.The contents of tumor necrosis factor(TNF)-αin colonic tissue and calcitonin-gene-related peptide(CGRP)in serum were measured by ELISA.The protein expression of serotonin[5-hydroxytryptamide(5-HT)],serotonin transporter(SERT),chromogranin A(Cg A)and CGRP incolon tissue was measured by immunohistochemistry.RESULTS:SGD inhibited colonic motility dysfunction and VHL in rats with IBS.Blockers of transient receptor potential(TRP)vanilloid 1(TRPV1)(Ruthenium Red)and TRP ankyrin-1(TRPA1)(HC-030031)and activator of protease-activated receptor(PAR)4 increased the pain pressure threshold,whereas activators of PAR2and TRPV4 decreased the pain pressure threshold in rats with IBS.The effect of SGD on pain pressure threshold in these rats was abolished by activators of TRPV1(capsaicin),TRPV4(RN1747),TRPA1(Polygodial)and PAR2(AC55541).In addition,CGRP levels in serum and colonic tissue were both increased in these rats.TNF-αlevel in colonic tissue was also significantly upregulated.However,the levels of 5-HT,SERT and Cg A in colonic tissue were decreased.All these pathological changes in rats with IBS were attenuated by SGD.CONCLUSION:SGD alleviated VHL and attenuated colon motility in IBS,partly by regulating TRPV1,TRPV4,TRPA1,PAR2,5-HT,Cg A and SERT,and reducing CGRP and TNF-αlevel.

Optogenetics-induced activation of glutamate receptors improves memory function in mice with Alzheimer’s disease

Optogenetics is a combination of optics and genetics technology that can be used to activate or inhibit specific cells in tissues. It has been used to treat Parkinson’s disease, epilepsy and neurological diseases, but rarely Alzheimer’s disease. Adeno-associated virus carrying the CaMK promoter driving the optogenetic channelrhodopsin-2 (CHR2) gene (or without the CHR2 gene, as control) was injected into the bilateral dentate gyri, followed by repeated intrahippocampal injections of soluble low-molecular-weight amyloid-β1–42 peptide (Aβ1–42). Subsequently, the region was stimulated with a 473 nm laser (1–3 ms, 10 Hz, 5 minutes). The novel object recognition test was conducted to test memory function in mice. Immunohistochemical staining was performed to analyze the numbers of NeuN and synapsin Ia/b-positive cells in the hippocampus. Western blot assay was carried out to analyze the expression levels of glial fibrillary acidic protein, NeuN, synapsin Ia/b, metabotropic glutamate receptor-1a (mGluR-1a), mGluR-5, N-methyl-D-aspartate receptor subunit NR1, glutamate receptor 2, interleukin-1β, interleukin-6 and interleukin-10. Optogenetic stimulation improved working and short-term memory in mice with Alzheimer’s disease. This neuroprotective effect was associated with increased expression of NR1, glutamate receptor 2 and mGluR-5 in the hippocampus, and decreased expression of glial fibrillary acidic protein and interleukin-6. Our results show that optogenetics can be used to regulate the neuronal-glial network to ameliorate memory functions in mice with Alzheimer’s disease. The study was approved by the Animal Resources Committee of Jinan University, China (approval No. LL-KT-2011134) on February 28, 2011.

Effect of ω-3 Polyunsaturated Fatty Acid on Toll-like Receptors in Patients with Severe Multiple Trauma

This study examined the effects of ω-3 polyunsaturated fatty acid（ω-3PUFA） on the expression of toll-like receptor 2（TLR2）,toll-like receptor 4（TLR4） and some related inflammatory factors in peripheral blood mononuclear cells（PBMCs） of patients with early-stage severe multiple trauma.Thirty-two patients who were admitted to the Department of Traumatic Surgery,Tongji Hospital（Wuhan,China） between May 2010 and November 2010,and diagnosed as having severe multiple trauma with a injury severity score（ISS） no less than 16,were enrolled in the study and divided into two groups at random（n=16 in each）：ω-3PUFA group and control group in which routine parenteral nutrition supplemented with ω-3PUFA or not was administered to the patients in two groups for consecutive 7 days.Peripheral blood from these patients was collected within 2 h of admission（day 0）,and 1,3,5 and 7 days after the nutritional support.PBMCs were isolated and used for detection of the mRNA and protein expression of TLR2 and TLR4 by using real-time PCR and flow cytometry respectively,the levels of NF-κB by quantum dots-based immunofluorescence assay,the levels of TNF-α,IL-2,IL-6 and COX-2 by ELISA,respectively.The results showed that the mRNA and protein expression of TLR2 and TLR4 in PBMCs was significantly lower in ω-3PUFA group than in control group 5 and 7 days after nutrition support（both P0.05）.The levels of TNF-α,IL-2,IL-6 and COX-2 were found to be substantially decreased in PBMCs in ω-3PUFA group as compared with control group at 5th and 7th day（P0.05 for all）.It was concluded that ω-3PUFA can remarkably decrease the expression of TLR2,TLR4 and some related inflammatory factors in NF-κB signaling pathway in PBMCs of patients with severe multiple trauma,which suggests that ω-3PUFA may suppress the excessive inflammatory response meditated by the TLRs/NF-κB signaling pathway.

Estrogen affects neuropathic pain through upregulating N-methyl-D-aspartate acid receptor 1 expression in the dorsal root ganglion of rats

Estrogen affects the generation and transmission of neuropathic pain,but the specific regulatory mechanism is still unclear.Activation of the N-methyl-D-aspartate acid receptor 1（NMDAR1） plays an important role in the production and maintenance of hyperalgesia and allodynia.The present study was conducted to determine whether a relationship exists between estrogen and NMDAR1 in peripheral nerve pain.A chronic sciatic nerve constriction injury model of chronic neuropathic pain was established in rats.These rats were then subcutaneously injected with 17β-estradiol,the NMDAR1 antagonist D（-）-2-amino-5-phosphonopentanoic acid（AP-5）,or both once daily for 15 days.Compared with injured drug na？ve rats,rats with chronic sciatic nerve injury that were administered estradiol showed a lower paw withdrawal mechanical threshold and a shorter paw withdrawal thermal latency,indicating increased sensitivity to mechanical and thermal pain.Estrogen administration was also associated with increased expression of NMDAR1 immunoreactivity（as assessed by immunohistochemistry） and protein（as determined by western blot assay） in spinal dorsal root ganglia.This 17β-estradiol-induced increase in NMDAR1 expression was blocked by co-administration with AP-5,whereas AP-5 alone did not affect NMDAR1 expression.These results suggest that 17β-estradiol administration significantly reduced mechanical and thermal pain thresholds in rats with chronic constriction of the sciatic nerve,and that the mechanism for this increased sensitivity may be related to the upregulation of NMDAR1 expression in dorsal root ganglia.

Increased Cellular Invasion and Proliferation via Estrogen Receptor after 17-<i>β</i>-Estradiol Treatment in Breast Cancer Cells Using Stable Isotopic Labeling with Amino Acids in Cell Culture (SILAC)

17-β-estradiol (estrogen) is a steroid hormone important to human development;however, high levels of this molecule are associated with increased risk of breast cancer primarily due to estrogen’s ability to bind and activate the estrogen receptor (ER) and initiate gene transcription. Currently, estrogen mechanisms of action are classified as genomic and non-genomic and occur in an ER-dependent and ER-independent manner. In this study, we examine estrogen signaling pathways, by measuring changes in protein expression as a function of time of exposure to estrogen in both ER-positive (MCF-7) and ER-negative (MDA-MB-231) cell lines. Using a robust experimental design utilizing isotopic labeling, two-dimensional LC-MS, and bioinformatics analysis, we report genomic and non-genomic ER regulated estrogen responsive proteins. We find a little over 200 proteins differentially expressed after estrogen treatment. Cell proliferation, transcription, actin filament capping and cell to cell signaling are significantly enriched in the MCF-7 cell line alone. Translational elongation and proteolysis are enriched in both cell lines. Subsets of the proteins presented in this study are for the first time directly associated with estrogen signaling in mammary carcinoma cells. We find that estrogen affected the expression of proteins involved in numerous processes that are related to tumorigenesis such as increased cellular division and invasion in an ER-dependent manner. Moreover, we identified negative regulation of apoptosis as a non-genomic process of estrogen. This study complements gene expression studies and highlights the need for both genomic and proteomic analyses in unraveling the complex mechanisms by which estrogen affects progression of breast cancer.

Effects of autoantibodies against AT1-receptor and angiotensin Ⅱ on refractory hypertension

Objective The study will explore effects of the autoantibodies against AT1 receptor and angiotensin Ⅱ on the refractory hypertension. Methods Seventy-seven patients (46 men and 31 women) with essential hypertension were divided into groups of refractory hypertension (RH) and hypertension (HT) according to the 1999 WHO-ISH Guidelines for the Management of Hypertension. Forty normotensives (22 men) were recruited as controls. The mean age was 54. 3±13 years old in RH group, 53. 5±9 years old in HT group and 51. 2±11. 9 years old in normotensives (NT) group. The mean blood pressure was 154. 2±9. 4/98. 4± 8. 2 mmHg in RH group and 130. 1±7. 6/80. 5±6. 7 mmHg in HT group after combination drug therapy of hypertension for 4 weeks. Blood pressure in NT group was 120. 8±11. 7/76. 4 ± 7. 2 mmHg. The epitope of the 2nd extracellular loops of AT1 receptor was synthesized and used as antigens to screen the autoantibodies by ELISA. Plasma angiotensin (Ang) II were examined by a radioimmunoassay. Results The autoantibodies against AT1 receptor were positive in 18 (46. 15 %) patients with RH, in 4 (10. 5 % ) hypertension and in 3 (7. 5 % ) normotensives, P < 0. 01. Ang Ⅱwas 57. 01±52. 63 pmol/L in patients with RH. Both the autoantibodies positive and the Ang Ⅱ increasing were 4 (10. 3 % ) cases, both normal were 7 (17. 9 % ) cases, the autoantibodies positive or Ang II increasing was all of 14 (35. 9 % ) cases (x2 = 0. 09, P>0. 05) . There was no relationship between the autoantibodies against AT1 receptor and the angiotensin Ⅱ in refractory hypertension. Conclusion The autoantibodies against AT1 receptor and Ang Ⅱ might be two independent factors in developing of refractory hypertension. The findings suggest that AT1 receptor an-tagnist used in the treatment of refractory hypertension might have an important value.

Glycosylation-independent binding to extracellular domains 11-13 of mannose-6-phosphate/insulin-like growth factor-2 receptor mediates the effects of soluble CREG on the phenotypic proliferation of vascular smooth muscle cells

Background The present study aimed to investigate the detailed mode and specific sites for their binding as well as the functional relevance of this binding in the phenotypic proliferation of vascular smooth muscle cells(SMCs). Methods CREG knocked-down SMCs were employed to evaluate the biological activity of wtCREG and mCREG.Expressions of SMC differentiation markers SM myosin heavy chain(SM-MHC),SM-actin,heavy caldesmon and myocardin were determined by Western blotting using specific antibodies. Cellular growth of SMCs was assessed by bromide dewuridine (BrdU) incorporation and cell cycle analysis on fluorescence-activated cell sorting(FACS).A solid-phase binding assay was used to study the binding of CREG to extracellular domains of M6P/IGF2R.The cellular co-localization of the two recombinant CREGs with M6P/IGF2R was detected on SMC surface by immunoprecipitation and immunofluorescence analysis.Results The molecular weight of wtCREG was around 30 kD while that of the mCREG was～25 kD.Treatment of wtCREG with PNGase F reduced its molecular weight from～30 kD to～25 kD,whereas PNGase F treatment had no effect on the molecular weight of mCREG.Both wtCREG and mCREG proteins enhanced SMC differentiation,inhibited BrdU incorporation,and arrested cell cycle progression when added to the culture medium.In CREG knocked-down SMCs,the amount of CREG detected by immunoblotting in M6P/IGF2R immunoprecipitates was significantly reduced when compared to normal cells.Both recombinant CREGs co-immunoprecipitated with M6P/IGF2R, although slightly reduced amount of the mutant CREG was detected in M6P/IGF2R immunoprecipitates.Immunostaining revealed that His-tagged CREGs co-localized with IGF2R on the cell surface in a glycosylation-independent manner.In vitro binding assay showed that CREGs bound to M6P/ IGF2R extracellular domains 7-10 and 11-13 in a glycosylation -dependent and -independent manner,respectively.Further blocking experiments using soluble M6P/IGF2R fragments and M6P/IGF2R neutralizing antibody indicated that the biological activities of recombinant CREGs in SMC growth and the up-regulation of SMC differentiation markers were all abolished by treatment with the M6P/IGF2R neutralizing antibody. However,although the growth inhibitory effect of wtCREG was nearly abolished by D7-10 or D11-13,the effect of mCREG was only reversed by Dll-13,indicating that the binding to domains 11-13 is required for CREG to modulate the proliferation of SMCs.Conclusions These data suggest that solubleCREG proteins can exert their biological function via binding to the extracellular domains 7-10 and 11-13 of cell surface M6P/IGF2R in both a glycosylation-dependent and -independent manner.

LncRNA AFAP1-AS1 exhibits oncogenic characteristics and promotes gemcitabine-resistance of cervical cancer cells through miR-7-5p/EGFR axis

Background:Drug resistance is the main factor contributing to cancer recurrence and poor prognosis.Exploration of drug resistance-related mechanisms and effective therapeutic targets are the aim of molecular targeted therapy.In our study,the role of long non-coding RNA(lncRNA)AFAP1-AS1 in gemcitabine resistance and related mechanisms were explored in cervical cancer cells.Methods:Gemcitabine-resistant cervical cancer cell lines HT-3-Gem and SW756-Gem were constructed using the gemcitabine concentration gradient method.The overall survival rates and recurrence-free survival rates were evaluated by Kaplan-Meier analysis.The interaction was verified through a Dual-luciferase reporter gene assay and a Biotinylated RNA pull-down assay.Cell proliferation ability was assessed through methyl-thiazolyl-tetrazolium(MTT),soft agar,and colony formation experiments.Cell cycle and apoptosis were detected byflow cytometry.Results:Up-regulation of AFAP1-AS1 in cervical cancer predicted a poor prognosis.Besides,patients in the gemcitabine-resistance group had higher levels of AFAP1-AS1 than the gemcitabine-sensitive group.AFAP1-AS1 promoted tumor growth and induced gemcitabine tolerance of cervical cancer cells.In addition,AFAP1-AS1 mediated epidermal growth factor receptor(EGFR)expression by serving as a molecular sponge for microRNA-7a-5p(miR-7-5p).This present study also proved that the knockdown of EGFR or overexpression of miR-7a-5p abolished the accelerative role of AFAP1-AS1 overexpression in cancer progression and gemcitabine tolerance.Conclusions:In general,the AFAP1-AS1/miR-7-5p/EGFR axis was tightly related to the progression and gemcitabine tolerance of cervical cancer,providing potential targets for the management of cervical cancer.

Inhibition of 5-HT_3 Receptors-activated Currents by Cannabinoids in Rat Trigeminal Ganglion Neurons

This study investigated the modulatory effect of synthetic cannabinoids WIN55,212-2 on 5-HT3 receptor-activated currents (I5-HT3) in cultured rat trigeminal ganglion (TG) neurons using whole-cell patch clamp technique. The results showed that: (1) The majority of examined neurons (78.70%) were sensitive to 5-HT (3–300 μmol/L). 5-HT induced inward currents in a concentration-dependent manner and the currents were blocked by ICS 205-930 (1 μmol/L), a selective antagonist of the 5-HT3 receptor; (2) Pre-application of WIN55,212-2 (0.01–1 μmol/L) significantly inhibited I5-HT3 reversibly in concentration-dependent and voltage-independent manners. The concentra-tion-response curve of 5-HT3 receptor was shifted downward by WIN55,212-2 without any change of the threshold value. The EC50 values of two curves were very close (17.5±4.5) mmol/L vs. (15.2±4.5) mmol/L and WIN55,212-2 decreased the maximal amplitude of I5-HT3 by (48.65±4.15)%; (3) Neither AM281, a selective CB1 receptor antagonist, nor AM630, a selective CB2 receptor antagonist reversed the inhibition of I5-HT3 by WIN55,212-2; (4) When WIN55,212-2 was given from 15 to 120 s before 5-HT application, inhibitory effect was gradually increased and the maximal inhibition took place at 90 s, and the inhibition remained at the same level after 90 s. We are led to concluded that-WIN55,212-2 inhibited I5-HT3 significantly and neither CB1 receptor antagonist nor CB2 receptor antagonist could reverse the inhibition of I5-HT3 by WIN55,212-2. Moreover, WIN55,212-2 is not an open channel blocker (OCB) of 5-HT3 receptor. WIN55,212-2 significantly inhibited 5-HT-activated currents in a non-competitive manner. The inhibition of I5-HT3 by WIN55,212-2 is probably new one of peripheral analgesic mechanisms of WIN55,212-2, but the mechanism by which WIN55,212-2 inhibits I5-HT3 warrants further investigation.

(-)-Stepholodine induced enhancement of cardiac muscle contractions mediated by D_1 receptors

Objective To investigate the effect of(-)-Stepholidine(SPD)on enhancing D1 receptor mediated contraction of cardiac muscle in isolated rat heart and to examine whether SPD has a direct effect on the heart dopamine D1 receptors.SPD an active ingredient of the Chinese herb Stephania intermedia,binds to dopamine D1 and D2 like receptors.Biochemical,electrophysiological and behavioural experiments have provided strong evidence that SPD is both a D(1/5)agonist and a D(2/4)antagonist,which could indicate unique antipsychotic properties.Methods Normal adult rat working hearts were isolated by Langendorff technique.Results SPD significantly increased the cardiac muscle contraction in a dose-dependent manner.The selective D1 dopamine receptor antagonist SCH23390(1 μM)blocked the SPD induced heart contraction,however,neither the β-receptor antagonist propranolol(1 μM)nor the α1-receptor antagonist prazosin(1 μM)had any effect on blocking SPD induced heart contractions.Moreover,the L-type Ca2+ channel inhibitor nimodipine(1 μM)completely blocked the effect of SPD on cardiac muscle contraction.Conclusions SPD show the effect on enhancing contraction of isolated rat heart through activating L-type Ca2+ channel mediated by heart D1 receptors.

miR-141-3p Suppresses Expression of Androgen Receptors and Functions as a Tumor Suppressor Gene in Prostate Carcinogenesis

Background: Prostate cancer (PCa) is a leading cause of tumor mortality in Western societies. In China, the PCa mortality rate is increasing yearly. Androgen receptors (ARs) and microRNAs (miRNAs) play central roles in prostate carcinogenesis and progression. Methods: To characterize the underlying molecular mechanisms, we compared the miRNA profiles of early PCa (G ≤ 7), advanced PCa (G > 7) and non-tumor prostate tissues using deep-sequencing. The target genes of differentially expressed miRNAs were predicted by bioinformatics analysis and confirmed by luciferase reporter assays and Western blot (WB) and quantitative reverse transcription-PCR (qRT-PCR) analyses. Finally, we performed in vitro functional studies by inducing or inhibiting miR-141-3p expression using an artificial mimic or inhibitor. Results: A computational search implicated the open reading frame (ORF) of AR mRNA as a potential miR-141-3p target site. The qRT-PCR, WB and luciferase reporter assays revealed a reverse regulatory effect of miR-141-3p on AR. Mutation of the potential miR-141-3p binding site in the AR ORF resulted in a loss of responsiveness to the corresponding miRNA. Moreover, miR-141-3p expression levels were unchanged in early PCas, but were obviously increased in advanced PCas. MiR-141-3p overexpression inhibited RWPE-1 cell proliferation, mobility, and prohibited the entry of cells into the G2-S-M phase;miR-141-3p inhibition had the inverse effects. At the same time, we tested miR-141-3p’s functions in PC-3 and VCaP prostate cancer cell lines. Conclusions: Taken together, our results indicate that miR-141-3p targets AR and its downstream signaling pathways, and functions as a tumor suppressor miR in PCa carcinogenesis by suppressing cell growth and mobility, but the effect is not significant in maglinant PCas. MiR-141-3p is implicated as a novel therapeutic target for early PCa.

5-HT₄Receptor Agonists for the Treatment of Alzheimer’s Dsease

Alzheimer’s disease (AD) is a progressive neurological disorder primarily affecting new memory formation as well as retrieval of previously acquired memories. According to World Health Organization, current global population suffering from cognitive impairment is estimated to 37 million. The number is projected to double in next one and half decade. Half of the population afflicted with dementia is represented by AD patients. Current therapies, which provide marginal symptomatic relief to AD patients, are effective only in half of the patient population. In depth understanding of the molecular mechanism of the disease is urgently required to develop more effective therapies. Therapies in clinical development may either offer symptomatic relief to patients or provide pure disease modifications, thus limiting benefit to patients. 5-HT4 receptor agonists offer an attractive option for the treatment of AD patients. Activation of 5- HT4 receptor under preclinical conditions is demonstrated to improve neurotransmission and enhance the release of acetylcholine resulting in the memory formation. In various cell based and animal models, partial 5-HT4 receptor agonists are demonstrated to promote the release of soluble amyloid precursor protein alpha and block the release of amyloid beta peptide offering suitable candidates as disease modification agents. Remarkably, 5-HT4 receptor agonists are also reported to induce neurogenesis in hippocampus as well as enteric system through the activation of cyclic AMP response element binding protein in rodents. Taken together, 5-HT4 agonists address all major facets of Alzheimer’s disease and may provide therapeutic potential for other neurological disorders.

Effects of (-)-Epigallocatechin gallate on some protein factors involved in the epidermal growth factor receptor signaling pathway

（-）-Epigallocatechin gallate （EGCG）, a major polyphenolic constituent of green tea, can inhibit activity of specific receptor tyrosine kinases （RTKs） and related downstream signal transduction pathways, resulting in the control of unwanted cell proliferation. The epidermal growth factor receptor （EGFR） signaling pathway is one of the most important pathways that regulates growth, survival,proliferation and differentiation in mammalian cells. This review addresses the effects of EGCG on some protein factors involved in the EGFR signaling pathway in a direct or indirect manner. Based on our understanding of the interaction between EGCG and these factors, and based on their structures, EGCG could be used as a lead compound for designing and synthesizing novel drugs with significant biological activity.