Suppression of immunoglobulin E-mediated allergic responses by regulator of G protein signaling 13.

Mast cells elicit allergic responses through degranulation and release of proinflammatory mediators after antigen crosslinking of the immunoglobulin E receptor FcepsilonRI. Proteins of the 'regulator of G protein signaling' (RGS) family negatively control signaling mediated by G protein-coupled receptors through GTPase-accelerating protein activity. Here we show that RGS13 inhibited allergic responses by physically interacting with the regulatory p85alpha subunit of phosphatidylinositol-3-OH kinase in mast cells and disrupting its association with an FcepsilonRI-activated scaffolding complex. Rgs13-/- mice had enhanced immunoglobulin E-mediated mast cell degranulation and anaphylaxis. Thus, RGS13 inhibits the assembly of immune receptor-induced signalosomes in mast cells. Abnormal RGS13 expression or function may contribute to disorders of amplified mast cell activity, such as idiopathic anaphylaxis.

Tyrosine phosphorylation switching of a G protein.

Heterotrimeric G protein complexes are molecular switches relaying extracellular signals sensed by G protein-coupled receptors (GPCRs) to downstream targets in the cytoplasm, which effect cellular responses. In the plant heterotrimeric GTPase cycle, GTP hydrolysis, rather than nucleotide exchange, is the rate-limiting reaction and is accelerated by a receptor-like regulator of G signaling (RGS) protein. We hypothesized that posttranslational modification of the Gα subunit in the G protein complex regulates the RGS-dependent GTPase cycle. Our structural analyses identified an invariant phosphorylated tyrosine residue (Tyr166 in the Arabidopsis Gα subunit AtGPA1) located in the intramolecular domain interface where nucleotide binding and hydrolysis occur. We also identified a receptor-like kinase that phosphorylates AtGPA1 in a Tyr166-dependent manner. Discrete molecular dynamics simulations predicted that phosphorylated Tyr166 forms a salt bridge in this interface and potentially affects the RGS protein-accelerated GTPase cycle. Using a Tyr166 phosphomimetic substitution, we found that the cognate RGS protein binds more tightly to the GDP-bound Gα substrate, consequently reducing its ability to accelerate GTPase activity. In conclusion, we propose that phosphorylation of Tyr166 in AtGPA1 changes the binding pattern with AtRGS1 and thereby attenuates the steady-state rate of the GTPase cycle. We coin this newly identified mechanism "substrate phosphoswitching."

Diagnosing the RGS11 Lung Cancer Biomarker: The Integration of Competitive Immunoassay and Isothermal Nucleic Acid Exponential Amplification Reaction.

Lung cancer is the primary cause of cancer-associated mortality worldwide, which makes the identification of reliable lung cancer biomarkers a pressing need for early diagnosis and prognosis. RGS11, which is a regulator of G-protein signaling and also a lung cancer biomarker, plays an important role in cancer-related metastasis. However, trace levels of RGS11 (in the range of pg/mL) in serum samples make it difficult to quantify using currently available enzyme-linked immunosorbent assay (ELISA) kits and, therefore, this hinders progress in the discovery of new approaches for treating lung cancer. The aim of this study is to develop a rapid, sensitive, and reliable platform for the detection of RGS11 lung cancer biomarker based on a suspension immunoassay coupled with an isothermal exponential amplification strategy. Our study was initiated by the functionalization of magnetic beads with anti-RGS11 antibodies (Ab-MB) by EDC (1-ethyl-3-(3-(dimethylamino)propyl)-carbodiimide)/NHS ( N-hydroxysulfosuccinimide) activation. Ab-MB served as a sensing probe for the competitive immunorecognitions between known concentrations of His-tag RGS11 and unknown concentrations of target RGS11 in serum. The reporter anti-His antibodies, which were modified with primers that induced an isothermal exponential amplification reaction, were subsequently introduced to the reaction mixture that resulted in the formation of immunosandwich complexes. The exponentially amplified DNA duplex that was intercalated with SYBR Green was designated as a signal reporter for the assessment of RGS11 in an inversely proportional relationship. The sensing platform was excellent for the determination of RGS11 with an exceptional detection limit of 148 fg/mL and a linear dynamic range of 0.1-10 pg/mL using a minimal sample volume (20 µL) and with a reaction time of 1.5 h. In addition, we challenged the sensing platform with RGS11-spiked samples (in 2× diluted serum), and an acceptable recovery rate (>90%) was observed. Finally, 24 clinical samples acquired from patients with advanced lung cancer (C), inflammation (I), and heart failure (H) were analyzed by this newly developed sensing platform and a commercial ELISA kit for validation. This sensing platform has potential in biomedical applications for clinically diagnosing liquid biopsy samples for patients with lung cancer. Moreover, the universal design of our proposed system is easily adapted to detect any other protein if a His-tag recombinant protein is available.

Dynamic G protein alpha signaling in Arabidopsis innate immunity.

Heterotrimeric G proteins composed of Gα, Gß and Gγ subunits are evolutionarily conserved signaling modules involved in diverse biological processes in plants and animals. The role and action of Gα remain largely enigmatic in plant innate immunity. We have recently demonstrated that Arabidopsis Gα (GPA1) is a key component of a new immune signaling pathway activated by bacteria-secreted proteases. Here we show that GPA1 is also involved in the signaling network of Arabidopsis in response to the bacterial flagellin epitope flg22. Specifically, GPA1 plays a pivotal role in an immune pathway involving the flg22 receptor FLS2, co-receptor BAK1, Regulator of G Signaling 1 (RGS1), and Arabidopsis Gß (AGB1), in which flg22 elicits GPA1/AGB1 dissociation from the FLS2/BAK1/RGS1 receptor complex. Consequently, we observed flg22-induced degradation of FLS2, BAK1 and RGS1 but not GPA1 or AGB1. We also found that GPA1 constitutively interacts with the NADPH oxidase RbohD to potentiate flg22-induced ROS burst independently of the central cytoplasmic kinase BIK1. Taken together, our work sheds multiple novel insights into the functions and regulatory mechanisms of GPA1 in Arabidopsis innate immunity.

Normal Thymocyte Egress, T Cell Trafficking, and CD4+ T Cell Homeostasis Require Interactions between RGS Proteins and Gαi2.

Adaptive immunity depends on mature thymocytes leaving the thymus to enter the bloodstream and the trafficking of T cells through lymphoid organs. Both of these require heterotrimeric Gαi protein signaling, whose intensity and duration are controlled by the regulator of G protein signaling (RGS) proteins. In this study, we show that RGS protein/Gαi2 interactions are essential for normal thymocyte egress, T cell trafficking, and homeostasis. Mature thymocytes with a Gαi2 mutation that disables RGS protein binding accumulated in the perivascular channels of thymic corticomedullary venules. Severe reductions in peripheral naive CD4+ T cells and regulatory T cells occurred. The mutant CD4+ T cells adhered poorly to high endothelial venules and exhibited defects in lymph node entrance and egress. The kinetics of chemokine receptor signaling were disturbed, including chemokine- induced integrin activation. Despite the thymic and lymph node egress defects, sphingosine-1-phosphate signaling was not obviously perturbed. This study reveals how RGS proteins modulate Gαi2 signaling to facilitate thymocyte egress and T cell trafficking.

RGS4 Overexpression in Lung Attenuates Airway Hyperresponsiveness in Mice.

A cardinal feature of asthma is airway hyperresponsiveness (AHR) to spasmogens, many of which activate G protein-coupled receptors (GPCRs) on airway smooth muscle (ASM) cells. Asthma subtypes associated with allergy are characterized by eosinophilic inflammation in the lung due to the type 2 immune response to allergens and proinflammatory mediators that promote AHR. The degree to which intrinsic abnormalities of ASM contribute to this phenotype remains unknown. The regulators of G protein signaling (RGS) proteins are a large group of intracellular proteins that inhibit GPCR signaling pathways. RGS2- and RGS5-deficient mice develop AHR spontaneously. Although RGS4 is upregulated in ASM from patients with severe asthma, the effects of increased RGS4 expression on AHR in vivo are unknown. Here, we examined the impact of forced RGS4 overexpression in lung on AHR using transgenic (Tg) mice. Tg RGS4 was expressed in bronchial epithelium and ASM in vivo, and protein expression in lung was increased at least 4-fold in Tg mice compared with wild-type (WT) mice. Lung slices from Tg mice contracted less in response to the m3 muscarinic receptor agonist methacholine compared with the WT, although airway resistance in live, unchallenged mice of both strains was similar. Tg mice were partially protected against AHR induced by fungal allergen challenge due to weakened contraction signaling in ASM and reduced type 2 cytokine (IL-5 and IL-13) levels in Tg mice compared with the WT. These results provide support for the hypothesis that increasing RGS4 expression and/or function could be a viable therapeutic strategy for asthma.

Marked induction of the helix-loop-helix protein Id3 promotes the gammadelta T cell fate and renders their functional maturation Notch independent.

alphabeta and gammadelta T cells arise from a common thymocyte progenitor during development in the thymus. Emerging evidence suggests that the pre-T cell receptor (pre-TCR) and gammadelta T cell receptor (gammadeltaTCR) play instructional roles in specifying the alphabeta and gammadelta T-lineage fates, respectively. Nevertheless, the signaling pathways differentially engaged to specify fate and promote the development of these lineages remain poorly understood. Here, we show that differential activation of the extracellular signal-related kinase (ERK)-early growth response gene (Egr)-inhibitor of DNA binding 3 (Id3) pathway plays a defining role in this process. In particular, Id3 expression served to regulate adoption of the gammadelta fate. Moreover, Id3 was both necessary and sufficient to enable gammadelta-lineage cells to differentiate independently of Notch signaling and become competent IFNgamma-producing effectors. Taken together, these findings identify Id3 as a central player that controls both adoption of the gammadelta fate and its maturation in the thymus.

An essential role for RGS protein/Gαi2 interactions in B lymphocyte-directed cell migration and trafficking.

Chemokines engage B lymphocyte surface receptors, triggering heterotrimeric G protein Gαi subunit guanine nucleotide exchange. RGS proteins limit the duration that Gαi subunits remain GTP bound, and the loss of an individual RGS protein typically enhances chemokine receptor signaling. In this study, we show that B cells carrying a Gαi2 (G184S/G184S) mutation that disables all RGS protein/Gαi2 interactions exhibit an unexpectedly severe reduction in chemokine receptor signaling. The Gαi2 (G184S/G184S) B cells have markedly elevated basal calcium levels, but poor chemokine-induced increases, enhanced nonspecific migration, but extremely poor chemotaxis. In striking contrast, the Gαi2 (G184S/G184S) B cells exhibited enhanced sensitivity to sphingosine 1-phosphate (S1P). S1P elicited heightened intracellular calcium responses and enhanced S1P-triggered cell migration. Mice with the Gαi2 (G184S/G184S) mutation displayed excessive numbers of germinal center-like structures; abnormal serum Ig profiles; and aberrant B lymphocyte trafficking. These findings establish an essential role for RGS proteins in B cell chemoattractant signaling and for the proper position of B lymphocytes in lymphoid organs.

Identification of novel immune phenotypes for allergic and nonallergic childhood asthma.

BACKGROUND: Childhood asthma is classified into allergic asthma (AA) and nonallergic asthma (NA), yet both are treated identically, with only partial success. OBJECTIVE: We sought to identify novel immune phenotypes for childhood AA and NA. METHODS: The Clinical Asthma Research Association cohort study includes 275 steroid-naive 4- to 15-year-old German children (healthy control subjects [HCs], patients with AA, and patients with NA). In PBMCs both quantitative and functional analysis of regulatory T (Treg) and TH17 cells (flow cytometry/Treg cell suppression) before/after anti-CD3/CD28, lipid A, and peptidoglycan stimulation were performed. Cytokines and gene expression, as assessed by using Luminex or transcriptomics/quantitative real-time RT-PCR, were analyzed by means of regression analysis. Linear discriminant analysis was applied to discriminate between phenotypes. RESULTS: The 3 phenotypes were immunologically well discriminated by means of microarray and protein analysis with linear discriminant analysis. Patients with AA were characterized by increased Treg cells compared with those in HCs but not those in patients with NA. Treg cells from patients with AA, but not patients with NA, significantly suppressed IL-5, IL-13, and IFN-γ secretion. Patients with AA had decreased expression of chloride intracellular channel 4 (CLIC4) and tuberous sclerosis 1 (TSC1), important innate immunity regulators. Patients with NA were characterized by increased proinflammatory IL-1ß levels, neutrophil counts, and IL-17-shifted immunity. In parallel, expressions of anti-inflammatory IL37, proline-serine-threonine phosphatase-interacting protein 2 (PSTPIP2), and the neutrophil-associated genes CD93, triggering receptor expressed on myeloid cells 1 (TREM1), and regulator of G-protein signaling 13 (RGS13) were increased in patients with NA. A shared TH2 immunity was present in both asthma phenotypes. CONCLUSION: Novel immune-regulatory mechanisms in childhood asthma identified increased Treg cells in patients with AA compared with those in HCs but not those in NA and decreased innate immunity genes for patients with AA, the first potentially indicating a counterregulatory mechanism to suppress cytokines yet not sufficient to control allergic inflammation. Very distinctly, patients with NA showed an IL-17-shifted proinflammatory immunity, promoting neutrophil inflammation and less functional Treg cells. Identification of these unique pathways provides a profound basis for future strategies for individualized prediction of asthma development, disease course, and prevention.

RGS16 restricts the pro-inflammatory response of monocytes.

Immune cells express powerful and harmful effectors that require tight regulation. Heterotrimeric G proteins are critical mediators in translating extracellular signals into cell responses, which need a fine-tuned regulation for the control of cell activation. Regulator of G-protein signalling 16 (RGS16) has been identified as a key factor of G protein-mediated activation in lymphocytes, modulating inflammatory and survival responses of various cell types. However, data about the expression of this regulatory protein in monocytes are scarce, and it has remained unclear whether activation and migration of these cells are regulated by RGS16. In this study, the impact of RGS16 on the production of inflammatory cytokines by activated human monocytes was investigated in vitro using the human promonocytic cell line THP-1 as a model. Gain and loss of function experiments showed that RGS16 overexpression reduces the expression of pro-inflammatory cytokines IL-1ß, IL-6, IL-8 and TNFα, while RGS16 knockdown by RNAi upregulates IL-1ß, IL-6 and TNFα but not IL-8. RGS16 knockdown was also shown to enhance Pam3-mediated induction of the anti-inflammatory cytokine IL-10. Our results indicate that RGS16 restricts the activation-induced pro-inflammatory profile in myeloid cells.

Loss of regulator of G protein signaling 5 promotes airway hyperresponsiveness in the absence of allergic inflammation.

BACKGROUND: Although eosinophilic inflammation typifies allergic asthma, it is not a prerequisite for airway hyperresponsiveness (AHR), suggesting that underlying abnormalities in structural cells, such as airway smooth muscle (ASM), contribute to the asthmatic diathesis. Dysregulation of procontractile G protein-coupled receptor (GPCR) signaling in ASM could mediate enhanced contractility. OBJECTIVE: We explored the role of a regulator of procontractile GPCR signaling, regulator of G protein signaling 5 (RGS5), in unprovoked and allergen-induced AHR. METHODS: We evaluated GPCR-evoked Ca(2+) signaling, precision-cut lung slice (PCLS) contraction, and lung inflammation in naive and Aspergillus fumigatus-challenged wild-type and Rgs5(-/-) mice. We analyzed lung resistance and dynamic compliance in live anesthetized mice using invasive plethysmography. RESULTS: Loss of RGS5 promoted constitutive AHR because of enhanced GPCR-induced Ca(2+) mobilization in ASM. PCLSs from naive Rgs5(-/-) mice contracted maximally at baseline independently of allergen challenge. RGS5 deficiency had little effect on the parameters of allergic inflammation, including cell counts in bronchoalveolar lavage fluid, mucin production, ASM mass, and subepithelial collagen deposition. Unexpectedly, induced IL-13 and IL-33 levels were much lower in challenged lungs from Rgs5(-/-) mice relative to those seen in wild-type mice. CONCLUSION: Loss of RGS5 confers spontaneous AHR in mice in the absence of allergic inflammation. Because it is selectively expressed in ASM within the lung and does not promote inflammation, RGS5 might be a therapeutic target for asthma.

Regulator of G-protein signaling 18 integrates activating and inhibitory signaling in platelets.

Regulator of G-protein signaling 18 (RGS18) is a GTPase-activating protein for the G-α-q and G-α-i subunits of heterotrimeric G-proteins that turns off signaling by G-protein coupled receptors. RGS18 is highly expressed in platelets. In the present study, we show that the 14-3-3γ protein binds to phosphorylated serines 49 and 218 of RGS18. Platelet activation by thrombin, thromboxane A2, or ADP stimulates the association of 14-3-3 and RGS18, probably by increasing the phosphorylation of serine 49. In contrast, treatment of platelets with prostacyclin and nitric oxide, which trigger inhibitory cyclic nucleotide signaling involving cyclic AMP-dependent protein kinase A (PKA) and cyclic GMP-dependent protein kinase I (PKGI), induces the phosphorylation of serine 216 of RGS18 and the detachment of 14-3-3. Serine 216 phosphorylation is able to block 14-3-3 binding to RGS18 even in the presence of thrombin, thromboxane A2, or ADP. 14-3-3-deficient RGS18 is more active compared with 14-3-3-bound RGS18, leading to a more pronounced inhibition of thrombin-induced release of calcium ions from intracellular stores. Therefore, PKA- and PKGI-mediated detachment of 14-3-3 activates RGS18 to block Gq-dependent calcium signaling. These findings indicate cross-talk between platelet activation and inhibition pathways at the level of RGS18 and Gq.

RGS16 attenuates pulmonary Th2/Th17 inflammatory responses.

The regulators of G protein signaling (RGS) protein superfamily negatively controls G protein-coupled receptor signal transduction pathways. RGS16 is enriched in activated/effector T lymphocytes. In this paper, we show that RGS16 constrains pulmonary inflammation by regulating chemokine-induced T cell trafficking in response to challenge with Schistosoma mansoni. Naive Rgs16(-/-) mice were "primed" for inflammation by accumulation of CCR10(+) T cells in the lung. Upon pathogen exposure, these mice developed more robust granulomatous lung fibrosis than wild-type counterparts. Distinct Th2 or putative Th17 subsets expressing CCR4 or CCR10 accumulated more rapidly in Rgs16(-/-) lungs following challenge and produced proinflammatory cytokines IL-13 and IL-17B. CCR4(+)Rgs16(-/-) Th2 cells migrated excessively to CCL17 and localized aberrantly in challenged lungs. T lymphocytes were partially excluded from lung granulomas in Rgs16(-/-) mice, instead forming peribronchial/perivascular aggregates. Thus, RGS16-mediated confinement of T cells to Schistosome granulomas mitigates widespread cytokine-mediated pulmonary inflammation.

Anti-RGS8 paraneoplastic cerebellar ataxia is preferentially associated with a particular subtype of Hodgkin's lymphoma.

Ataxia with anti-regulator of G-protein signaling 8 autoantibodies (RGS8-Abs) is an autoimmune disease recently described in four patients. The present study aimed to identify other patients with RGS8-Abs, describe their clinical features, including the link between RGS8-related autoimmune cerebellar ataxia (ACA) and cancer. Patients with RGS8-Abs were identified retrospectively in the biological collections of the French Reference Center for Paraneoplastic Neurological Syndrome and the University of California San Francisco Center for Encephalitis and Meningitis. Clinical data were collected, and cerebrospinal fluid, serum, and tumor pathological samples were retrieved to characterize the autoantibodies and the associated malignancies. Only three patients with RGS8-Abs were identified. All of them presented with a pure cerebellar ataxia of mild to severe course, unresponsive to current immunotherapy regimens for ACA. Two patients presented with a Hodgkin lymphoma of the rare specific subtype called nodular lymphocyte-predominant Hodgkin lymphoma, with very mild extension. Autoantibodies detected in all patients enriched the same epitope on the RGS8 protein, which is an intracellular protein physiologically expressed in Purkinje cells but also ectopically expressed specifically in lymphoma cells of patients with RGS8-related ACA. The present results and those of the four cases previously described suggest that RGS8-Abs define a new paraneoplastic neurological syndrome of extreme rarity found mostly in middle-aged males that associates pure cerebellar ataxia and a particular lymphoma specifically expressing the RGS8 antigen. As in other paraneoplastic ACA with intracellular antigen, the disease course is severe, and patients tend to exhibit a poor response to immune therapy.

R4 regulators of G protein signaling (RGS) identify an ancient MHC-linked synteny group.

Regulators of G protein signaling (RGS) are key regulators of G protein signaling. RGS proteins of the R4 RGS group are composed of a mere RGS domain and are mainly involved in immune response modulation. In both human and mouse, most genes encoding the R4 RGS proteins are located in the same region of chromosome 1. We show here that the RGS1/RGS16 neighborhood constitutes a synteny group well conserved across tetrapods and closely linked to the MHC paralogon of chromosome 1. Genes located in the RGS1/RGS16 region have paralogs close to the MHC on chromosome 6 or close to the other MHC paralogons. In amphioxus, a cephalochordate, these genes possess orthologs that are located in the same scaffolds as a number of markers defining the proto-MHC in this species (Abi-Rached et al., Nat Genet 31:100-115, 2002). We therefore propose that the RGS1/RGS16 region provides useful markers to investigate the origins and the evolution of the MHC. In addition, we show that some genes of the region appear to have immune functions not only in human, but also in Xenopus.

Cutting Edge: Regulator of G protein signaling-1 selectively regulates gut T cell trafficking and colitic potential.

The RGS1 gene is associated with celiac disease, multiple sclerosis, and type I diabetes, which are all T cell-mediated pathologies, yet there is no reported analysis of regulator of G protein signaling (RGS)1 biology in human T cells. This study shows that RGS1 expression is substantially higher in T cells from human gut versus peripheral blood and that this can be exaggerated in intestinal inflammation. Elevated RGS1 levels profoundly reduce T cell migration to lymphoid-homing chemokines, whereas RGS1 depletion selectively enhances such chemotaxis in gut T cells and impairs their colitogenic potential. These findings provide a revised framework in which to view the linkage of RGS1 to inflammatory disease.

Regulator of G protein signaling 2 is a key modulator of airway hyperresponsiveness.

BACKGROUND: Drugs targeting individual G protein-coupled receptors are used as asthma therapies, but this strategy is limited because of G protein-coupled receptor signal redundancy. Regulator of G protein signaling 2 (RGS2), an intracellular selective inhibitor of multiple bronchoconstrictor receptors, may play a central role in the pathophysiology and treatment of asthma. OBJECTIVE: We defined functions and mechanisms of RGS2 in regulating airway hyperresponsiveness (AHR), the pathophysiologic hallmark of asthma. METHODS: Real-time PCR and Western blot were used to determine changes in RGS2 expression in ovalbumin-sensitized/-challenged mice. We also used immunohistochemistry and real-time PCR to compare RGS2 expression between human asthmatic and control subjects. The AHR of RGS2 knockout mice was assessed by using invasive tracheostomy and unrestrained plethysmography. Effects of loss of RGS2 on mouse airway smooth muscle (ASM) remodeling, contraction, intracellular Ca(2+), and mitogenic signaling were determined in vivo and in vitro. RESULTS: RGS2 was highly expressed in human and murine bronchial epithelium and ASM and was markedly downregulated in lungs of ovalbumin-sensitized/-challenged mice. Lung tissues and blood monocytes from asthma patients expressed significantly lower RGS2 protein (lung) and mRNA (monocytes) than from nonasthma subjects. The extent of reduction of RGS2 on human monocytes correlated with increased AHR. RGS2 knockout caused spontaneous AHR in mice. Loss of RGS2 augmented Ca(2+) mobilization and contraction of ASM cells. Loss of RGS2 also increased ASM mass and stimulated ASM cell growth via extracellular signal-regulated kinase and phosphatidylinositol 3-kinase pathways. CONCLUSION: We identified RGS2 as a potent modulator of AHR and a potential novel therapeutic target for asthma.

Rgs16 promotes antitumor CD8+ T cell exhaustion.

T cells become functionally exhausted in tumors, limiting T cell-based immunotherapies. Although several transcription factors regulating the exhausted T (Tex) cell differentiation are known, comparatively little is known about the regulators of Tex cell survival. Here, we reported that the regulator of G protein signaling 16 (Rgs-16) suppressed Tex cell survival in tumors. By performing lineage tracing using reporter mice in which mCherry marked Rgs16-expressing cells, we identified that Rgs16+CD8+ tumor-infiltrating lymphocytes (TILs) were terminally differentiated, expressed low levels of T cell factor 1 (Tcf1), and underwent apoptosis as early as 6 days after the onset of Rgs16 expression. Rgs16 deficiency inhibited CD8+ T cell apoptosis and promoted antitumor effector functions of CD8+ T cells. Furthermore, Rgs16 deficiency synergized with programmed cell death protein 1 (PD-1) blockade to enhance antitumor CD8+ T cell responses. Proteomics revealed that Rgs16 interacted with the scaffold protein IQGAP1, suppressed the recruitment of Ras and B-Raf, and inhibited Erk1 activation. Rgs16 deficiency enhanced antitumor CD8+ TIL survival in an Erk1-dependent manner. Loss of function of Erk1 decreased antitumor functions of Rgs16-deficient CD8+ T cells. RGS16 mRNA expression levels in CD8+ TILs of patients with melanoma negatively correlated with genes associated with T cell stemness, such as SELL, TCF7, and IL7R, and predicted low responses to PD-1 blockade. This study uncovers Rgs16 as an inhibitor of Tex cell survival in tumors and has implications for improving T cell-based immunotherapies.

Fatty acid metabolism is related to the immune microenvironment changes of gastric cancer and RGS2 is a new tumor biomarker.

Background: Alterations in lipid metabolism promote tumor progression. However, the role of lipid metabolism in the occurrence and development of gastric cancer have not been fully clarified. Method: Here, genes that are related to fatty acid metabolism and differentially-expressed between normal and gastric cancer tissues were identified in the TCGA-STAD cohort. The intersection of identified differentially-expressed genes with Geneset was determined to obtain 78 fatty acid metabolism-related genes. The ConsensusClusterPlus R package was used to perform differentially-expressed genes, which yielded divided two gastric cancer subtypes termed cluster 1 and cluster 2. Results: Patients in cluster 2 was found to display poorer prognosis than patients in cluster 1. Using machine learning method to select 8 differentially expressed genes among subtypes to construct fatty acid prognostic risk score model (FARS), which was found to display good prognostic efficacy. We also identified that certain anticancer drugs, such as bortezomib, elesclomol, GW843682X, and nilotinib, showed significant sensitivity in the high FARS score group. RGS2 was selected as the core gene upon an analysis of the gastric cancer single-cell, and Western blotting and immunofluorescence staining results revealed high level of expression of this gene in gastric cancer cells. The results of immunohistochemical staining showed that a large amount of RGS2 was deposited in the stroma in gastric cancer. A pan-cancer analysis also revealed a significant association of RGS2 with TMB, TIDE, and CD8+ T-cell infiltration in other cancer types as well. RGS2 may thus be studied further as a new target for immunotherapy in future studies on gastric cancer. Conclusion: In summary, the FARS model developed here enhances our understanding of lipid metabolism in the TME in gastric cancer, and provides a theoretical basis for predicting tumor prognosis and clinical treatment.

Inhibiting RGS1 attenuates secondary inflammation response and tissue degradation via the TLR/TRIF/NF-κB pathway in macrophage post spinal cord injury.

Macrophage-dominated inflammation by the activation of Toll-like receptor (TLR) pathway leads to neurological disruption after spinal cord injury (SCI). Regulator of G-protein signaling 1 (RGS1) is reported to be a regulator in inflammation. The present study thus purposes to identify the unknown role of RGS1 mediating TLR on inflammation post SCI. A mouse model of traumatic SCI was established by a mechanical trauma at T10. The mice underwent SCI and a macrophage line activated by lipopolysaccharide (LPS) were treated with shRNA-RGS1 to elucidate the role of RGS1 in inflammatory progression. The inflammatory factors were measured, and the degree of histology and function protection were determined. The expression levels of RGS1, myeloid differentiation primary response protein 88 (Myd88), (TIR-domain-containing adaptor inducing interferon-ß (TRIF), p38, metalloproteinase (MMP)-2, and MMP-9 were determined. RGS1 was robustly increased both in LPS-activated macrophage and SCI mice. The TLR signaling pathway-induced inflammation was suppressed by RGS1 knockdown. shRNA-mediated silence of RGS1 was exhibited a prominent decrease in TNF-α, IL-1ß and IL-6 via TLR/TRIF/ nuclear factor kappa-B (NF-κB) axis. Depletion of RGS1 also inhibited MMP-induced tissue degradation via MAPK-p38 pathway in SCI mice. Moreover, suppression of RGS1 improved spinal cord histology and function recovery. These findings suggest that RGS1 regulates inflammation and tissue disruption via TLR/TRIF/NF-κB signaling pathway in mice with SCI, thereby explaining a novel target that regulates macrophage inflammation post SCI.