Effect of rgs4 overexpression on related protein expression of mglur5-mediated signaling pathway in methamphetamine-dependent rat striatum / 中国药理学通报

Aim To investigate the effect of the regulator of G-protein signaling 4(RGS4) overexpression in rat striatum on the related protein expression of metabolic glutamate receptor 5(mGluR5) signaling pathway and the conditioned place preference(CPP) behavior in rats, by establishing the METH-dependent CPP model. Methods Rats were divided into five groups: Normal, normal saline(NS), METH, Ad5-RGS4-EGFP and Ad5-EGFP group. Normal group was without any administration, while the striatum of the other groups were respectively stereotactic injected with phosphate buffer methamphetamine (METH)-depardent soline (PBS), PBS, overexpressed adenovirus vector Ad5-RGS4-EGFP and negative control adenovirus vector Ad5-EGFP. The CPP behavior of rats in each group was analyzed. The expression of RGS4, mGluR5, Gαq, PLC1 was measured in rat striatum tissue by Western blot. Results The difference of CPP in Ad5-RGS4-EGFP group decreased compared with that in METH group and Ad5-EGFP group(P 0.05). PLCβ1 expression changed with no significant difference. Conclusions RGS4 overexpression in striatum is able to alleviate the CPP behavior in METH-dependent rats, and its mechanism may be associated with the overexpression of RGS4 in METH-dependent rat striatum, which could down-regulate the mGluR5-mediated Gαq and PLCβ1 signaling pathway.

Expression regulation and functional analysis of RGS2 and RGS4 in adipogenic and osteogenic differentiation of human mesenchymal stem cells

BACKGROUND: Understanding the molecular basis underlying the formation of bone-forming osteocytes and lipid-storing adipocytes will help provide insights into the cause of disorders originating in stem/progenitor cells and develop therapeutic treatments for bone- or adipose-related diseases. In this study, the role of RGS2 and RGS4, two members of the regulators of G protein signaling (RGS) family, was investigated during adipogenenic and osteogenenic differentiation of human mesenchymal stem cells (hMSCs). RESULTS: Expression of RGS2 and RGS4 were found to be inversely regulated during adipogenesis induced by dexamethasone (DEX) and 3-isobutyl-methylxanthine, regardless if insulin was present, with RGS2 up-regulated and RGS4 down-regulated in response to adipogenic induction. RGS2 expression was also up-regulated during osteogenesis at a level similar to that induced by treatment of DEX alone, a shared component of adipogenic and osteogenic differentiation inducing media, but significantly lower than the level induced by adipogenic inducing media. RGS4 expression was down-regulated during the first 48 h of osteogenesis but up-regulated afterwards, in both cases at levels similar to that induced by DEX alone. Expression knock-down using small interfering RNA against RGS2 resulted in decreased differentiation efficiency during both adipogenesis and osteogenesis. On the other hand, expression knock-down of RGS4 also resulted in decreased adipogenic differentiation but increased osteogenic differentiation. CONCLUSIONS: RGS2 and RGS4 are differentially regulated during adipogenic and osteogenic differentiation of hMSCs. In addition, both RGS2 and RGS4 play positive roles during adipogenesis but opposing roles during osteogenesis, with RGS2 as a positive regulator and RGS4 as a negative regulator. These results imply that members of RGS proteins may play multifaceted roles during human adipogenesis and osteogenesis to balance or counterbalance each other's function during those processes.

Clinical significance of expression of RGS4 in pediatric nephroblastoma tissue / 天津医药

Objective To investigate the expression levels of regulator of G-protein signaling 4 (RGS4) in pediatric nephroblastoma and pericancerous tissues, and explore the relationship between RGS4 and the occurrence and development of pediatric nephroblastoma. Methods Thirty-seven samples of pediatric nephroblastoma tissues and 8 samples of pericancerous tissues were collected after surgery to detect the expression of RGS4 protein by immunohistochemistry. Another 8 samples of fresh cancer tissues and corresponding pericancerous tissues were collected to detect the mRNA and protein levels of RGS4 by qRT-PCR and Western blot assay, respectively. Results Immunohistochemistry results showed that RGS4 protein was positively expressed both in pediatric nephroblastoma and pericancerous tissues, and its high expression rate was lower in pediatric nephroblastoma than that in pericancerous tissues [(37.83%(14/37) vs. 87.5%(7/8),χ2=4.675, P<0.05]. The expression level of RGS4 mRNA was significantly lower in pediatric nephroblastoma than that in pericancerous tissues (1.064 ± 0.549 vs. 5.374 ± 0.735, t=13.290, n=8, P < 0.01). Western blot results showed that the expression level of RGS4 protein was lower in pediatric nephroblastoma than that of pericancerous tissues (0.301±0.092 vs. 0.779 ± 0.041, t=13.424, n=8, P < 0.01). Conclusion The expression level of RGS4 is down-regulated in pediatric nephroblastoma, which may be related to the occurrence and development of pediatric nephroblastoma.

Expression of RGS4 and D2 receptor signaling pathway in striatum of methamphetamine-dependent CPP rats / 中国临床药理学与治疗学

AIM:To study the expression of signal transduction molecules in the striatum G protein protein 4 (RGS4) and dopamine D2 receptor (D2) in conditioned place preference (CPP) rats treated with methamphetamine (meth).METHODS:METH dependence CPP model was established (1 week and 2 weeks of METH dependence groups),The protein expression of RGS4 and D2,inhibitory G protein alpha-subunit (Gαi),mitogenactivated protein kinase (MAPK) in striatum were determined by Western blotting (WB).The changes of cyclic adenosine monophosphate (cAMP) content in striatum of rats were determined by enzyme linked immunosorbent assay (ELISA).RESULTS:Compared with saline control group,the average time of rats in the methamphetamine-paired chamber for two groups was increased (P ＜ 0.05).Compared with saline control group,RGS4 protein expressions in the two METH dependent groups were reduced (P ＜0.01);compared with 1 week of METH dependence group,that of 2 weeks group was reduced significantly(P ＜ 0.05).D2,Gαi,MAPK protein and cAMP expressions in the two METH dependent groups were increased (P ＜ 0.01);compared with 1 week of METH dependence group,those of 2 weeks were increased significantly (P ＜ 0.05).CONCLUSION:RGS4 and D2 receptor signaling pathways in striatum have changed in METH dependent rats,RGS4 may be involved in the regulation of METH-dependent D2 receptor signaling pathway in METH dependent rats.

Role of Regulators of G-Protein Signaling 4 in Ca2+ Signaling in Mouse Pancreatic Acinar Cells

Regulators of G-protein signaling (RGS) proteins are regulators of Ca2+ signaling that accelerate the GTPase activity of the G-protein alpha-subunit. RGS1, RGS2, RGS4, and RGS16 are expressed in the pancreas, and RGS2 regulates G-protein coupled receptor (GPCR)-induced Ca2+ oscillations. However, the role of RGS4 in Ca2+ signaling in pancreatic acinar cells is unknown. In this study, we investigated the mechanism of GPCR-induced Ca2+ signaling in pancreatic acinar cells derived from RGS4-/- mice. RGS4-/- acinar cells showed an enhanced stimulus intensity response to a muscarinic receptor agonist in pancreatic acinar cells. Moreover, deletion of RGS4 increased the frequency of Ca2+ oscillations. RGS4-/- cells also showed increased expression of sarco/endoplasmic reticulum Ca2+ ATPase type 2. However, there were no significant alterations, such as Ca2+ signaling in treated high dose of agonist and its related amylase secretion activity, in acinar cells from RGS4-/- mice. These results indicate that RGS4 protein regulates Ca2+ signaling in mouse pancreatic acinar cells.