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Shelley B Hooks - One of the best experts on this subject based on the ideXlab platform.
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rgs10 physically and functionally interacts with stim2 and requires store operated calcium entry to regulate pro inflammatory gene expression in microglia
Cellular Signalling, 2021Co-Authors: Menbere Wendimu, Mohammed Alqinyah, Faris Almutairi, Stephen A Vella, Phillip Dean, Roseanne Davilarivera, Shima Rayatpisheh, James A Wohlschlegel, Silvia N J Moreno, Shelley B HooksAbstract:Chronic activation of microglia is a driving factor in the progression of neuroinflammatory diseases, and mechanisms that regulate microglial inflammatory signaling are potential targets for novel therapeutics. Regulator of G protein Signaling 10 is the most abundant RGS protein in microglia, where it suppresses inflammatory gene expression and reduces microglia-mediated neurotoxicity. In particular, microglial RGS10 downregulates the expression of pro-inflammatory mediators including cyclooxygenase 2 (COX-2) following stimulation with lipopolysaccharide (LPS). However, the mechanism by which RGS10 affects inflammatory signaling is unknown and is independent of its canonical G protein targeted mechanism. Here, we sought to identify non-canonical RGS10 interacting partners that mediate its anti-inflammatory mechanism. Through RGS10 co-immunoprecipitation coupled with mass spectrometry, we identified STIM2, an endoplasmic reticulum (ER) localized calcium sensor and a component of the store-operated calcium entry (SOCE) machinery, as a novel RGS10 interacting protein in microglia. Direct immunoprecipitation experiments confirmed RGS10-STIM2 interaction in multiple microglia and macrophage cell lines, as well as in primary cells, with no interaction observed with the homologue STIM1. We further determined that STIM2, Orai channels, and the calcium-dependent phosphatase calcineurin are essential for LPS-induced COX-2 production in microglia, and this pathway is required for the inhibitory effect of RGS10 on COX-2. Additionally, our data demonstrated that RGS10 suppresses SOCE triggered by ER calcium depletion and that ER calcium depletion, which induces SOCE, amplifies pro-inflammatory genes. In addition to COX-2, we also show that RGS10 suppresses the expression of pro-inflammatory cytokines in microglia in response to thrombin and LPS stimulation, and all of these effects require SOCE. Collectively, the physical and functional links between RGS10 and STIM2 suggest a complex regulatory network connecting RGS10, SOCE, and pro-inflammatory gene expression in microglia, with broad implications in the pathogenesis and treatment of chronic neuroinflammation.
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rgs10 regulates the expression of cyclooxygenase 2 and tumor necrosis factor alpha through a g protein independent mechanism
Molecular Pharmacology, 2018Co-Authors: Mohammed Alqinyah, Faris Almutairi, Menbere Wendimu, Shelley B HooksAbstract:The small regulator of G protein signaling protein RGS10 is a key regulator of neuroinflammation and ovarian cancer cell survival; however, the mechanism for RGS10 function in these cells is unknown and has not been linked to specific G protein pathways. RGS10 is highly enriched in microglia, and loss of RGS10 expression in microglia amplifies production of the inflammatory cytokine tumor necrosis factor α (TNFα) and enhances microglia-induced neurotoxicity. RGS10 also regulates cell survival and chemoresistance of ovarian cancer cells. Cyclooxygenase-2 (COX-2)-mediated production of prostaglandins such as prostaglandin E2 (PGE2) is a key factor in both neuroinflammation and cancer chemoresistance, suggesting it may be involved in RGS10 function in both cell types, but a connection between RGS10 and COX-2 has not been reported. To address these questions, we completed a mechanistic study to characterize RGS10 regulation of TNFα and COX-2 and to determine if these effects are mediated through a G protein-dependent mechanism. Our data show for the first time that loss of RGS10 expression significantly elevates stimulated COX-2 expression and PGE2 production in microglia. Furthermore, the elevated inflammatory signaling resulting from RGS10 loss was not affected by Gαi inhibition, and a RGS10 mutant that is unable to bind activated G proteins was as effective as wild type in inhibiting TNFα expression. Similarly, suppression of RGS10 in ovarian cancer cells enhanced TNFα and COX-2 expression, and this effect did not require Gi activity. Together, our data strongly indicate that RGS10 inhibits COX-2 expression by a G protein-independent mechanism to regulate inflammatory signaling in microglia and ovarian cancer cells.
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regulator of g protein signaling 10 rgs10 expression is transcriptionally silenced in activated microglia by histone deacetylase activity
Molecular Pharmacology, 2017Co-Authors: Mohammed Alqinyah, Ercan Cacan, Susanna F Greer, Mourad W. Ali, Nagini Maganti, Ruchi Yadav, Mei Gao, Hanrong Weng, Shelley B HooksAbstract:RGS10 has emerged as a key regulator of proinflammatory cytokine production in microglia, functioning as an important neuroprotective factor. Although RGS10 is normally expressed in microglia at high levels, expression is silenced in vitro following activation of TLR4 receptor. Given the ability of RGS10 to regulate inflammatory signaling, dynamic regulation of RGS10 levels in microglia may be an important mechanism to tune inflammatory responses. The goals of the current study were to confirm that RGS10 is suppressed in an in vivo inflammatory model of microglial activation and to determine the mechanism for activation-dependent silencing of Rgs10 expression in microglia. We demonstrate that endogenous RGS10 is present in spinal cord microglia, and RGS10 protein levels are suppressed in the spinal cord in a nerve injury-induced neuropathic pain mouse model. We show that the histone deacetylase (HDAC) enzyme inhibitor trichostatin A blocks the ability of lipopolysaccharide (LPS) to suppress Rgs10 transcription in BV-2 and primary microglia, demonstrating that HDAC enzymes are required for LPS silencing of Rgs10 Furthermore, we used chromatin immunoprecipitation to demonstrate that H3 histones at the Rgs10 proximal promoter are deacetylated in BV-2 microglia following LPS activation, and HDAC1 association at the Rgs10 promoter is enhanced following LPS stimulation. Finally, we have shown that sphingosine 1-phosphate, an endogenous microglial signaling mediator that inhibits HDAC activity, enhances basal Rgs10 expression in BV-2 microglia, suggesting that Rgs10 expression is dynamically regulated in microglia in response to multiple signals.
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abstract poster biol 1317 releasing the brakes on ovarian cancer cell survival epigenetic suppression of rgs10 in ovarian cancer chemoresistance
Clinical Cancer Research, 2015Co-Authors: Shelley B HooksAbstract:G-protein signaling pathways promote cell survival, which is aberrantly enhanced in chemoresistant ovarian cancer. Regulator of G-protein Signaling (RGS) proteins limit the strength of G-protein signaling, and therefore indirectly control cell survival. We have previously shown that RGS10 suppresses ovarian cancer cell growth and limits survival in the presence of cytotoxic chemotherapeutic drugs. Further, we have shown that RGS10 expression is suppressed in cell models of ovarian cancer chemoresistance, suggesting that ovarian cancer cells silence RGS10 expression to release the brakes on their growth and survival. However, the mechanisms governing RGS10 expression in ovarian cancer cells are poorly understood. In this study, we fully investigate the molecular mechanism of RGS10 suppression in ovarian cancer acquired chemoresistance, revealing key roles for epigenetic regulation by DNA hypermethylation and histone deacetylation. Pharmacological inhibition of DNA methyl-transferases (DNMTs) increases RGS10 expression in chemoresistant ovarian cancer cells, suggesting potential regulation by DNA methylation. Further, bisulfite sequencing analysis identified a region of the RGS10-1 promoter with significantly enhanced DNA methylation in chemoresistant A2780-AD cells relative to parental A2780 cells. More marked differences are observed in histone acetylation of the RGS10-1 promoter. Acetylated histone H3 associates with the RGS10-1 promoter was significantly lower in A2780-AD cells compared to parental cells, with a corresponding increase in histone deacetylase (HDAC) enzyme association. Further, both HDAC1 and DNMT1 exhibit aberrant association with RGS10 promoters in chemoresistant ovarian cancer cells. Knockdown of HDAC1 or DNMT1 expression, and pharmacological inhibition of DNMT or HDAC enzymatic activity, significantly increases RGS10 expression and cisplatin-mediated cell death. Finally, DNMT1 knock down decreases HDAC1 binding to the RGS10 promoter in chemoresistant cells, suggesting HDAC1 recruitment to RGS10 promoters requires DNMT1 activity. Our results suggest that HDAC1 and DNMT1 cooperatively contribute to the suppression of RGS10 during acquired chemoresistance and support inhibition of HDAC1 and DNMT1 as an adjuvant therapeutic approach to overcome ovarian cancer chemoresistance. Citation Format: Shelley Hooks, PhD. Releasing the brakes on ovarian cancer cell survival: epigenetic suppression of RGS10 in ovarian cancer chemoresistance [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-BIOL-1317.
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inhibition of hdac1 and dnmt1 modulate rgs10 expression and decrease ovarian cancer chemoresistance
PLOS ONE, 2014Co-Authors: Ercan Cacan, Nathaniel H Boyd, Susanna F Greer, Shelley B HooksAbstract:RGS10 is an important regulator of cell survival and chemoresistance in ovarian cancer. We recently showed that RGS10 transcript expression is suppressed during acquired chemoresistance in ovarian cancer. The suppression of RGS10 is due to DNA hypermethylation and histone deacetylation, two important mechanisms that contribute to silencing of tumor suppressor genes during cancer progression. Here, we fully investigate the molecular mechanisms of epigenetic silencing of RGS10 expression in chemoresistant A2780-AD ovarian cancer cells. We identify two important epigenetic regulators, HDAC1 and DNMT1, that exhibit aberrant association with RGS10 promoters in chemoresistant ovarian cancer cells. Knockdown of HDAC1 or DNMT1 expression, and pharmacological inhibition of DNMT or HDAC enzymatic activity, significantly increases RGS10 expression and cisplatin-mediated cell death. Finally, DNMT1 knock down also decreases HDAC1 binding to the RGS10 promoter in chemoresistant cells, suggesting HDAC1 recruitment to RGS10 promoters requires DNMT1 activity. Our results suggest that HDAC1 and DNMT1 contribute to the suppression of RGS10 during acquired chemoresistance and support inhibition of HDAC1 and DNMT1 as an adjuvant therapeutic approach to overcome ovarian cancer chemoresistance.
Jacques G Lussier - One of the best experts on this subject based on the ideXlab platform.
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expression and regulation of regulator of g protein signaling protein 2 rgs2 in equine and bovine follicles prior to ovulation molecular characterization of rgs2 transactivation in bovine granulosa cells
Biology of Reproduction, 2014Co-Authors: Khampoun Sayasith, Jean Sirois, Jacques G LussierAbstract:ABSTRACT The luteinizing hormone preovulatory surge stimulates several signal pathways essential for ovulation, and the regulator of G-protein signaling protein-2 (RGS2) is thought to be involved in this process. The objectives of this study were to characterize the regulation of RGS2 transcripts in equine and bovine follicles prior to ovulation and to determine its transcriptional control in bovine granulosa cells. To assess the regulation of equine RGS2 prior to ovulation, RT-PCR was performed using total RNA extracted from equine follicles collected at various times after human chorionic gonadotropin (hCG) injection. Results showed that RGS2 mRNA levels were very low at 0 h but markedly increased 12–39 h post-hCG (P < 0.05). In the bovine species, results revealed that RGS2 mRNA levels were low in small and dominant follicles and in ovulatory follicles obtained at 0 h, but markedly increased in ovulatory follicles 6–24 h post-hCG (P < 0.05). To study the molecular control of RGS2 expression, primary cu...
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expression and regulation of regulator of g protein signaling protein 2 rgs2 in equine and bovine follicles prior to ovulation molecular characterization of rgs2 transactivation in bovine granulosa cells
Biology of Reproduction, 2014Co-Authors: Khampoun Sayasith, Jean Sirois, Jacques G LussierAbstract:The luteinizing hormone preovulatory surge stimulates several signal pathways essential for ovulation, and the regulator of G-protein signaling protein-2 (RGS2) is thought to be involved in this process. The objectives of this study were to characterize the regulation of RGS2 transcripts in equine and bovine follicles prior to ovulation and to determine its transcriptional control in bovine granulosa cells. To assess the regulation of equine RGS2 prior to ovulation, RT-PCR was performed using total RNA extracted from equine follicles collected at various times after human chorionic gonadotropin (hCG) injection. Results showed that RGS2 mRNA levels were very low at 0 h but markedly increased 12-39 h post-hCG (P < 0.05). In the bovine species, results revealed that RGS2 mRNA levels were low in small and dominant follicles and in ovulatory follicles obtained at 0 h, but markedly increased in ovulatory follicles 6-24 h post-hCG (P < 0.05). To study the molecular control of RGS2 expression, primary cultures of bovine granulosa cells were used. Stimulation with forskolin induced an up-regulation of RGS2 mRNA in vitro. Studies using 5'-deletion mutants identified a minimal region containing full-length basal and forskolin-inducible RGS2 promoter activities. Site-directed mutagenesis indicated that these activities were dependent on CRE and ETS1 cis-elements. Electrophoretic mobility shift assays confirmed the involvement of these elements and revealed their interactions with CREB1 and ETS1 proteins. Chromatin immunoprecipitation assays confirmed endogenous interactions of these proteins with the RGS2 promoter in granulosa cells. Forskolin-inducible RGS2 promoter activity and mRNA expression were markedly decreased by PKA and ERK1/2 inhibitors, and treatment with an antagonist of PGR (RU486) and inhibitors of PTGS2 (NS398) and EGFR (PD153035) blocked the forskolin-dependent RGS2 transcript expression, suggesting the importance of RGS2 in ovulation. Collectively, this study reports for the first time the gonadotropin-dependent up-regulation of RGS2 in equine and bovine preovulatory follicles and presents some of the regulatory controls involved in RGS2 gene expression in granulosa cells.
Francis S Willard - One of the best experts on this subject based on the ideXlab platform.
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regulator of g protein signaling 21 rgs21 is an inhibitor of bitter gustatory signaling found in lingual and airway epithelia
Journal of Biological Chemistry, 2012Co-Authors: Staci Cohen, Brian K Buckley, Mickey Kosloff, Alaina L Garland, Dustin E Bosch, Gang Cheng, Harish Radhakrishna, Michael D Brown, Francis S WillardAbstract:Abstract The gustatory system detects tastants and transmits signals to the brain regarding ingested substances and nutrients. Although tastant receptors and taste signaling pathways have been identified, little is known about their regulation. Because bitter, sweet, and umami taste receptors are G protein-coupled receptors (GPCRs), we hypothesized that regulators of G protein signaling (RGS) proteins may be involved. The recent cloning of RGS21 from taste bud cells has implicated this protein in the regulation of taste signaling; however, the exact role of RGS21 has not been precisely defined. Here, we sought to determine the role of RGS21 in tastant responsiveness. Biochemical analyses confirmed in silico predictions that RGS21 acts as a GTPase-accelerating protein (GAP) for multiple G protein α subunits, including adenylyl cyclase-inhibitory (Gαi) subunits and those thought to be involved in tastant signal transduction. Using a combination of in situ hybridization, RT-PCR, immuno-histochemistry and immuno-fluorescence, we demonstrate that RGS21 is not only endogenously expressed in mouse taste buds but also in lung airway epithelial cells, which have previously been shown to express components of the taste signaling cascade. Furthermore, as shown by RT-PCR, the immortalized human airway cell line 16HBE was found to express transcripts for tastant receptors, RGS21, and downstream taste signaling components. Over- and underexpression of RGS21 in 16HBE cells confirmed that RGS21 acts to oppose bitter tastant signaling to cAMP and calcium second messenger changes. Our data collectively suggests that RGS21 modulates bitter taste signal transduction.
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structural determinants of g protein α subunit selectivity by regulator of g protein signaling 2 rgs2
Journal of Biological Chemistry, 2009Co-Authors: Adam J. Kimple, Francis S Willard, Vincent Setola, M Soundararajan, Stephanie Q Hutsell, A K Roos, Daniel J Urban, Brenda Temple, Bryan L Roth, S KnappAbstract:“Regulator of G-protein signaling” (RGS) proteins facilitate the termination of G protein-coupled receptor (GPCR) signaling via their ability to increase the intrinsic GTP hydrolysis rate of Gα subunits (known as GTPase-accelerating protein or “GAP” activity). RGS2 is unique in its in vitro potency and selectivity as a GAP for Gαq subunits. As many vasoconstrictive hormones signal via Gq heterotrimer-coupled receptors, it is perhaps not surprising that RGS2-deficient mice exhibit constitutive hypertension. However, to date the particular structural features within RGS2 determining its selectivity for Gαq over Gαi/o substrates have not been completely characterized. Here, we examine a trio of point mutations to RGS2 that elicits Gαi-directed binding and GAP activities without perturbing its association with Gαq. Using x-ray crystallography, we determined a model of the triple mutant RGS2 in complex with a transition state mimetic form of Gαi at 2.8-A resolution. Structural comparison with unliganded, wild type RGS2 and of other RGS domain/Gα complexes highlighted the roles of these residues in wild type RGS2 that weaken Gαi subunit association. Moreover, these three amino acids are seen to be evolutionarily conserved among organisms with modern cardiovascular systems, suggesting that RGS2 arose from the R4-subfamily of RGS proteins to have specialized activity as a potent and selective Gαq GAP that modulates cardiovascular function.
Mandi M. Murph - One of the best experts on this subject based on the ideXlab platform.
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suppression of the gtpase activating protein rgs10 increases rheb gtp and mtor signaling in ovarian cancer cells
Cancer Letters, 2015Co-Authors: Molly K Altman, Ali A Alshamrani, Wei Jia, Ha T Nguyen, Jada M Fambrough, Sterling K Tran, Mihir Patel, Pooya Hoseinzadeh, Aaron M Beedle, Mandi M. MurphAbstract:The regulator of G protein signaling 10 (RGS10) protein is a GTPase activating protein that accelerates the hydrolysis of GTP and therefore canonically inactivates G proteins, ultimately terminating signaling. Rheb is a small GTPase protein that shuttles between its GDP- and GTP-bound forms to activate mTOR. Since RGS10 suppression augments ovarian cancer cell viability, we sought to elucidate the molecular mechanism. Following RGS10 suppression in serum-free conditions, phosphorylation of mTOR, the eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1), p70S6K and S6 Ribosomal Protein appear. Furthermore, suppressing RGS10 increases activated Rheb, suggesting RGS10 antagonizes mTOR signaling via the small G-protein. The effects of RGS10 suppression are enhanced after stimulating cells with the growth factor, lysophosphatidic acid, and reduced with mTOR inhibitors, temsirolimus and INK-128. Suppression of RGS10 leads to an increase in cell proliferation, even in the presence of etoposide. In summary, the RGS10 suppression increases Rheb-GTP and mTOR signaling in ovarian cancer cells. Our results suggest that RGS10 could serve in a novel, and previously unknown, role by accelerating the hydrolysis of GTP from Rheb in ovarian cancer cells.
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transcriptional suppression dna methylation and histone deacetylation of the regulator of g protein signaling 10 rgs10 gene in ovarian cancer cells
PLOS ONE, 2013Co-Authors: Mourad Wagdy Ali, Mandi M. Murph, Ercan Cacan, Susanna F Greer, Yuying Liu, Jennifer Young Pierce, William T Creasman, Rajgopal Govindarajan, Scott T Eblen, Shelley B HooksAbstract:RGS10 regulates ovarian cancer cell growth and survival, and RGS10 expression is suppressed in cell models of ovarian cancer chemoresistance. However, the mechanisms governing RGS10 expression in ovarian cancer are poorly understood. Here we report RGS10 suppression in primary ovarian cancer and CAOV-3 ovarian cancer cells compared to immortalized ovarian surface epithelial (IOSE) cells, and in A2780-AD chemoresistant cells compared to parental A2780 cells. RGS10-1 and RGS10-2 transcripts are expressed in ovarian cancer cells, but only RGS10-1 is suppressed in A2780-AD and CAOV-3 cells, and the RGS10-1 promoter is uniquely enriched in CpG dinucleotides. Pharmacological inhibition of DNA methyl-transferases (DNMTs) increased RGS10 expression, suggesting potential regulation by DNA methylation. Bisulfite sequencing analysis identified a region of the RGS10-1 promoter with significantly enhanced DNA methylation in chemoresistant A2780-AD cells relative to parental A2780 cells. DNA methylation in CAOV-3 and IOSE cells was similar to A2780 cells. More marked differences were observed in histone acetylation of the RGS10-1 promoter. Acetylated histone H3 associated with the RGS10-1 promoter was significantly lower in A2780-AD cells compared to parental cells, with a corresponding increase in histone deacetylase (HDAC) enzyme association. Similarly, acetylated histone levels at the RGS10-1 promoter were markedly lower in CAOV-3 cells compared to IOSE cells, and HDAC1 binding was doubled in CAOV-3 cells. Finally, we show that pharmacological inhibition of DNMT or HDAC enzymes in chemoresistant A2780-AD cells increases RGS10 expression and enhances cisplatin toxicity. These data suggest that histone de-acetylation and DNA methylation correlate with RGS10 suppression and chemoresistance in ovarian cancer. Markers for loss of RGS10 expression may identify cancer cells with unique response to therapeutics.
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regulators of g protein signaling rgs10 and rgs17 regulate chemoresistance in ovarian cancer cells
Molecular Cancer, 2010Co-Authors: Shelley B Hooks, Phillip Callihan, Molly K Altman, Jillian H Hurst, Mandi M. MurphAbstract:A critical therapeutic challenge in epithelial ovarian carcinoma is the development of chemoresistance among tumor cells following exposure to first line chemotherapeutics. The molecular and genetic changes that drive the development of chemoresistance are unknown, and this lack of mechanistic insight is a major obstacle in preventing and predicting the occurrence of refractory disease. We have recently shown that Regulators of G-protein Signaling (RGS) proteins negatively regulate signaling by lysophosphatidic acid (LPA), a growth factor elevated in malignant ascites fluid that triggers oncogenic growth and survival signaling in ovarian cancer cells. The goal of this study was to determine the role of RGS protein expression in ovarian cancer chemoresistance. In this study, we find that RGS2, RGS5, RGS10 and RGS17 transcripts are expressed at significantly lower levels in cells resistant to chemotherapy compared with parental, chemo-sensitive cells in gene expression datasets of multiple models of chemoresistance. Further, exposure of SKOV-3 cells to cytotoxic chemotherapy causes acute, persistent downregulation of RGS10 and RGS17 transcript expression. Direct inhibition of RGS10 or RGS17 expression using siRNA knock-down significantly reduces chemotherapy-induced cell toxicity. The effects of cisplatin, vincristine, and docetaxel are inhibited following RGS10 and RGS17 knock-down in cell viability assays and phosphatidyl serine externalization assays in SKOV-3 cells and MDR-HeyA8 cells. We further show that AKT activation is higher following RGS10 knock-down and RGS 10 and RGS17 overexpression blocked LPA mediated activation of AKT, suggesting that RGS proteins may blunt AKT survival pathways. Taken together, our data suggest that chemotherapy exposure triggers loss of RGS10 and RGS17 expression in ovarian cancer cells, and that loss of expression contributes to the development of chemoresistance, possibly through amplification of endogenous AKT signals. Our results establish RGS10 and RGS17 as novel regulators of cell survival and chemoresistance in ovarian cancer cells and suggest that their reduced expression may be diagnostic of chemoresistance.
Malu G Tansey - One of the best experts on this subject based on the ideXlab platform.
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age related changes in regulator of g protein signaling rgs 10 expression in peripheral and central immune cells may influence the risk for age related degeneration
Neurobiology of Aging, 2015Co-Authors: George T Kannarkat, Jaekyung Lee, Jaegwon Chung, Chenere P Ramsey, Jianjun Chang, Isadora Porter, Danielle Oliver, Kennie R Shepherd, Malu G TanseyAbstract:Inflammation in the aging brain increases risk for neurodegenerative disease. In humans, the regulator of G-protein signaling-10 (RGS10) locus has been associated with age-related maculopathy. Chronic peripheral administration of lipopolysaccharide in the RGS10-null mice induces nigral dopaminergic (DA) degeneration, suggesting that RGS10 modulates neuroimmune interactions and may influence susceptibility to neurodegeneration. Because age is the strongest risk factor for neurodegenerative disease, we assessed whether RGS10 expression changes with age and whether aged RGS10-null mice have altered immune cell profiles. Loss of RGS10 in aged mice does not alter the regulation of nigral DA neurons but does alter B-cell, monocyte, microglial, and CD4+ T-cell populations and inflammatory cytokine levels in the cerebrospinal fluid. These results suggest that loss of RGS10 is associated with an age-dependent dysregulation of peripheral and central immune cells rather than dysregulation of DA neuron function.
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physiology of rgs10 in neurons and immune cells
Progress in Molecular Biology and Translational Science, 2015Co-Authors: Jaekyung Lee, Malu G TanseyAbstract:Regulator of G protein signaling-10 (RGS10), a GTPase-activating protein (GAP) for Gαi3, Gαq, and Gαz, belongs to the D/R12 subfamily based on the homology within the RGS domain and is one of the smallest RGS proteins, outside the RGS box. Although RGS10 lacks the flanking domains or motifs, RGS10 can be targeted to membrane by palmitoylation which markedly increases its net GAP activity. The cAMP-dependent protein kinase A phosphorylates RGS10 on serine 168 (Ser(168)) which promotes translocation of RGS10 from the cytosol to nucleus. In addition to its GAP function, RGS10 modulates adenylyl cyclase (AC) activity as well as the G protein-gated inwardly rectifying potassium channels. Although the roles of various RGS proteins have been well addressed in previous reviews, the function and mechanism of RGS10 in particular has not been reviewed in-depth. Moreover, recent arrays of studies implicate a role for RGS10 in immune and neuronal cells. RGS10 has been localized to various cell compartments including the cytoplasm and nucleus. In this chapter, we will review its role in neurons and immune cells.
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a novel function of rgs10 in effector t lymphocytes to augment mouse eae ba8p 126
Journal of Immunology, 2014Co-Authors: Jaekyung Lee, Jaegwon Chung, George T Kannarkat, Kareem L Graham, Malu G TanseyAbstract:A broad range of immune-based therapeutic drugs have been available for treatment of various autoimmune diseases but many have had limited success. Therefore, it is critical to identify additional cellular targets that can regulate the pathogenic response of immune cells. We hypothesize that GPCR modulator RGS proteins are important modulators of the immune responses involved in the development of multiple sclerosis (MS). Our hypothesis is based on reports that various SNPs in RGS proteins is highly correlated with the diagnosis of MS. Especially, an in-depth search of the GEO profiles database also revealed higher levels of RGS10 transcripts in MS patients’ PBMCs. Here, we showed RGS10-null mice displayed significantly milder clinical symptoms of EAE with reduced incidence and delayed disease onset. We observed that there were less numbers of CD45+ cells and CD4+ T cells in MOG35-55-immunized RGS10-null mice in the CNS. RGS10-null LN T cells were less proliferatative and produce less IFN-γ and IL-17 cytokines in response to MOG. Our data suggest a critical role for RGS10 in modulating disease by attenuating lymphocyte infiltration and/or peripheral immune responses during EAE. This is the first study ever conducted to elucidate the function of RGS10 in effector lymphocytes in the context of EAE. The identification of RGS10 as a central regulator of the inflammatory processes will open a possibility for developing more specific targeted therapy for the treatment of MS.
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critical role of regulator g protein signaling 10 rgs10 in modulating macrophage m1 m2 activation
PLOS ONE, 2013Co-Authors: Jaekyung Lee, Jaegwon Chung, George T Kannarkat, Malu G TanseyAbstract:Regulator of G protein signaling 10 (RGS10), a GTPase accelerating protein (GAP) for G alpha subunits, is a negative regulator of NF-κB in microglia. Here, we investigated the role of RGS10 in macrophages, a closely related myeloid-derived cell type. Features of classical versus alternative activation were assessed in Rgs10-/- peritoneal and bone marrow-derived macrophages upon LPS or IL-4 treatments, respectively. Our results showed that Rgs10-/- macrophages produced higher levels of pro-inflammatory cytokines including TNF, IL-1β and IL-12p70 in response to LPS treatment and exerted higher cytotoxicity on dopaminergic MN9D neuroblastoma cells. We also found that Rgs10-/- macrophages displayed a blunted M2 phenotype upon IL-4 priming. Specifically, Rgs10-/- macrophages displayed lower YM1 and Fizz1 mRNA levels as measured by QPCR compared to wild type macrophages upon IL-4 treatment and this response was not attributable to differences in IL-4 receptor expression. Importantly, phagocytic activities of Rgs10-/- macrophages were blunted in response to IL-4 priming and/or LPS treatments. However, there was no difference in chemotaxis between Rgs10-/- and WT macrophages. Our data indicate that Rgs10-/- macrophages displayed dysregulated M1 responses along with blunted M2 alternative activation responses, suggesting that RGS10 plays an important role in determining macrophage activation responses.
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rgs10 exerts a neuroprotective role through the pka c amp response element creb pathway in dopaminergic neuron like cells
Journal of Neurochemistry, 2012Co-Authors: Jaekyung Lee, Kirk M Druey, Jaegwon Chung, Malu G TanseyAbstract:Regulator of G-protein signaling-10 (RGS10) is a GTPase activating protein for Gαi/q/z subunits that is highly expressed in the immune system and in a broad range of brain regions including the hippocampus, striatum, dorsal raphe, and ventral midbrain. Previously, we reported that RGS10-null mice display increased vulnerability to chronic systemic inflammation-induced degeneration of nigral dopaminergic (DA) neurons. Given that RGS10 is expressed in DA neurons, we investigated the extent to which RGS10 regulates cell survival under conditions of inflammatory stress. Because of the inherent limitations associated with use of primary DA neurons for biochemical analyses, we employed a well-characterized ventral mesencephalon DA neuroblastoma cell line (MN9D) for our studies. We found that stable over-expression of RGS10 rendered them resistant to TNF-induced cytotoxicity; whereas MN9D cells expressing mutant RGS10-S168A (which is resistant to phosphorylation by protein kinase A at a serine residue that promotes its nuclear translocation) showed similar sensitivity to TNF as the parental MN9D cells. Using biochemical and pharmacologic approaches, we identified protein kinase A and the downstream phospho-cAMP response element-binding signaling pathway (and ruled out ERK 1/2, JNK, and NFkB) as key mediators of the neuroprotective effect of RGS10 against inflammatory stress.