Project description:Calcium is a critical signaling molecule in many cell types including immune cells. The calcium-release activated calcium channels (CRAC) responsible for store-operated calcium entry (SOCE) in immune cells are gated by STIM family members functioning as sensors of Ca2+ store content in the endoplasmic reticulum. We investigated the effect of SOCE blocker BTP2 on human peripheral blood mononuclear cells (PBMC) stimulated with the mitogen phytohemagglutinin (PHA).
Project description:Coordinated mineralization of soft tissue is central to organismal form and function, while dysregulated mineralization underlies several human pathologies. Oral epithelial derived ameloblasts are polarized, secretory cells responsible for generating enamel, the most mineralized substance in the human body. Defects in ameloblast development result in enamel anomalies, including amelogenesis imperfecta. Identifying proteins critical in ameloblast development can provide insight into specific pathologies associated with enamel related disorders or more broadly, mechanisms of mineralization. Previous studies identified a role for MEMO1 in bone mineralization; however, whether MEMO1 functions in the generation of additional mineralized structures remains unknown. Here, we identify a critical role for MEMO1 in enamel mineralization. First, we identified that Memo1 is expressed in ameloblasts and that conditional deletion of Memo1 from ameloblasts results in enamel defects, characterized by a decline in mineral density and tooth integrity. Molecular profiling of ameloblasts and their progenitors in Memo1 oral epithelial mutants revealed a disruption to cytoskeletal associated genes and a reduction in late stage ameloblast markers, relative to controls. Histology revealed that the molecular defects correlated with a disruption of the apical Tome’s process and the basolateral interacting, papillary layer, in Memo1 mutant ameloblasts. Finally, deletion of Memo1 from an oral epithelial ameloblast cell line, followed by cellular and molecular analyses, revealed altered cytoskeletal networks, relative to control cells. Collectively, our findings integrate MEMO1 into an emerging network of molecules important for ameloblast development and provide both in vivo and in vitro systems to further interrogate the relationship of cytoskeletal and amelogenesis-related defects.
Project description:This series of microarray experiments monitored the gene expression profiles for monoclonal cell lines (derived from HEK-293 parental cell culture) with high (H1, H15, H24, H36, H39) or low (L3, L28, L29) levels of store-operated Ca2+ entry (SOCE). For selection of clones, HEK-293 cells were loaded with indo-1 and sorted by FACS on the basis of their cyclopiazonic acid (CPA)-stimulated Ca2+ entry. Monoclonal cell lines were selected from the sorted cells and their levels of SOCE confirmed by monitoring thapsigargin-stimulated Ba2+ entry. Total RNA was extracted from cells immediately after removal from their growth environment. RNA was processed and hybridized to the Affymetrix HG-U133A chip. Two parallel hybridizations were done for each RNA preparation from each monoclonal cell line or from the parental HEK-293 cell culture.
Project description:Abstarct:Mutations in the endoplasmic reticulum (ER) Ca2+ sensor stromal interaction molecule 1 (STIM1) result is a number of disease states including abnormal enamel formation. However, these defects in enamel have remained unclear given a lack of animal models available. We generated Stim1/2K14Cre mice to ablate the activity of STIM1 and its homologue STIM2 in enamel cells. These mice showed impaired Ca2+ entry in enamel cells and although enamel formed, it was severely hypomineralized and mechanically weak. RNA-sequencing of enamel cells provided a global overview of loss of Ca2+ sensor activity. ER stress markers associated with unfolded protein response (UPR) were increased. Cell morphology was altered showing loss of the typical ruffled-border and mislocalized mitochondria. We also identified decreased glutathione system and potentially associated with this, increased ROS and abnormal mitochondria. The Ca2+ extrusion system and enamel gene expression were also altered. These data might represent the first in vivo study linking Stim1/2 ablation with increased UPR function, decreased glutathione metabolism, increased ROS and abnormal mitochondria. Loss of ER Ca2+ sensors Stim1/2 in enamel cells has substantial detrimental effects at the cell and mineral phase level.
Project description:Activated Foxp3+ regulatory T (Treg) cells differentiate into effector Treg (eTreg) cells to maintain peripheral immune homeostasis and tolerance. T cell receptor (TCR)-mediated induction and regulation of store-operated Ca2+ entry (SOCE) is essential for eTreg cell differentiation and function. However, SOCE regulation in Treg cells remains unclear. Here we show that inositol polyphosphate multikinase (IPMK), which generates inositol tetrakisphosphate and inositol pentakisphosphate, is a pivotal regulator of Treg cell differentiation downstream of TCR signaling. IPMK is highly expressed in TCR-stimulated Treg cells and promotes a TCR-induced Treg cell program. IPMK-deficient Treg cells display aberrant T cell activation and impaired differentiation into RORγt+ Treg cells, and tissue-resident Treg cells. Mechanistically, IPMK controls the generation of higher-order inositol phosphates, thereby promoting Ca2+ mobilization and Treg cell effector functions. Our findings identify IPMK as a critical regulator of TCR-mediated Ca2+ influx and highlight the importance of IPMK in Treg cell-mediated immune homeostasis.
Project description:T follicular helper (TFH) cells promote affinity maturation of B cells in germinal centers (GCs), whereas T follicular regulatory (TFR) cells limit GC reaction. Store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels mediated by STIM and ORAI proteins is a fundamental signaling pathway in T lymphocytes. Here we show that SOCE is required for the differentiation and function of both TFH and TFR cells. Conditional deletion of Stim1 and Stim2 genes in T cells or Treg cells results in spontaneous autoantibody production and humoral autoimmunity. Conversely, antibody-mediated immune responses following viral infection critically depend on SOCE in TFH cells. Mechanistically, STIM1 and STIM2 control early TFR and TFH cell differentiation through NFAT-mediated IRF4, BATF and Bcl-6 expression. SOCE plays a dual role in GC response by controlling TFH and TFR cell function, thus enabling protective B cell responses and preventing humoral autoimmunity. RNAseq analyses of WT and Stim1Stim2 DKO follicular T cells and non-follicular T cells; 4-6 mice per cohort in duplicates. Mice were infected for 10 days with LCMV.
Project description:Dental enamel, the hardest tissue in the human body, is derived from dental epithelial cell ameloblast-secreted enamel matrices. Enamel mineralization occurs in a strictly synchronized manner along with ameloblast maturation in association with ion transport and pH balance, and any disruption of these processes results in enamel hypomineralization. G-protein coupled receptors (GPCRs) function as transducers of external signals by activating associated G-proteins and regulate cellular physiology. Tissue-specific GPCRs play important roles in organ development, though their activities in tooth development remains poorly understood. The present results show that the adhesion-GPCR Gpr115 (Adgrf4) is highly and preferentially expressed in mature ameloblasts and plays a crucial role during enamel mineralization. To investigate the in vivo function of Gpr115, knockout (Gpr115-KO) mice were created and found to develop hypo-mineralized enamel, with a larger acidic area due to the dysregulation of ion composition. Transcriptomic analysis also revealed that deletion of Gpr115 disrupted pH homeostasis and ion transport processes in enamel formation. In addition, in vitro analyses using the dental epithelial cell line Cervical Loop-Derived Dental Epithelial (CLDE) cell demonstrated that Gpr115 is indispensable for the expression of carbonic anhydrase 6 (Car6), which has a critical role in enamel mineralization. Furthermore, an acidic condition induced Car6 expression under the regulation of Gpr115 in CLDE cells. Thus, we concluded that Gpr115 plays an important role in enamel mineralization via regulation of Car6 expression in ameloblasts. The present findings indicate a novel function of Gpr115 in ectodermal organ development and clarify the molecular mechanism of enamel formation.
Project description:T follicular helper (TFH) cells promote affinity maturation of B cells in germinal centers (GCs), whereas T follicular regulatory (TFR) cells limit GC reaction. Store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels mediated by STIM and ORAI proteins is a fundamental signaling pathway in T lymphocytes. Here we show that SOCE is required for the differentiation and function of both TFH and TFR cells. Conditional deletion of Stim1 and Stim2 genes in T cells or Treg cells results in spontaneous autoantibody production and humoral autoimmunity. Conversely, antibody-mediated immune responses following viral infection critically depend on SOCE in TFH cells. Mechanistically, STIM1 and STIM2 control early TFR and TFH cell differentiation through NFAT-mediated IRF4, BATF and Bcl-6 expression. SOCE plays a dual role in GC response by controlling TFH and TFR cell function, thus enabling protective B cell responses and preventing humoral autoimmunity.
Project description:This series of microarray experiments monitored the gene expression profiles for monoclonal cell lines (derived from HEK-293 parental cell culture) with high (H1, H15, H24, H36, H39) or low (L3, L28, L29) levels of store-operated Ca2+ entry (SOCE). For selection of clones, HEK-293 cells were loaded with indo-1 and sorted by FACS on the basis of their cyclopiazonic acid (CPA)-stimulated Ca2+ entry. Monoclonal cell lines were selected from the sorted cells and their levels of SOCE confirmed by monitoring thapsigargin-stimulated Ba2+ entry. Total RNA was extracted from cells immediately after removal from their growth environment. RNA was processed and hybridized to the Affymetrix HG-U133A chip. Two parallel hybridizations were done for each RNA preparation from each monoclonal cell line or from the parental HEK-293 cell culture. Keywords: parallel sample