The integrin alpha4beta7 forms a complex with cell-surface CD4 and defines a T-cell subset that is highly susceptible to infection by HIV-1.
Ontology highlight
ABSTRACT:
SUBMITTER: Cicala C
PROVIDER: S-EPMC2780317 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:The alpha4beta7 integrin promotes homing of T cells to intestinal sites. The alpha4 integrin subunit that pairs with beta7 integrin can also pair with beta1 integrin. In this paper, we show that the preferential pairing of beta1 integrin with alpha4 integrin regulates the expression of alpha4beta7 on T cells. In the absence of beta1 integrin, naive mouse CD4 T cells have increased alpha4beta7 expression, resulting in increased adhesion to mucosal addressin cell adhesion molecule-1 and enhanced homing to Peyer's patches (PP). In a reciprocal manner, overexpression of beta1 integrin causes the loss of alpha4beta7 expression and decreased homing to PP. A similar upregulation of beta1 integrin and suppression of alpha4beta7 expression occurs rapidly after CD4 T cell activation. beta1 integrin thus dominates beta7 integrin for alpha4 integrin pairing, thereby controlling the abundance of unpaired alpha4 integrin. Increasing the abundance of alpha4 integrin relative to beta1 integrin is critical to retinoic acid-mediated expression of alpha4beta7 integrin during T cell activation. In the absence of beta1 integrin, endogenous Ag-specific CD4 T cells uniformly express high levels of alpha4beta7 after Listeria monocytogenes infection. The resulting beta1-deficient early memory T cells have decreased localization to the bone marrow and enhanced localization to PP after infection. Thus, the preferential association of beta1 integrin with alpha4 integrin suppresses alpha4beta7 integrin expression and regulates the localization of memory CD4 T cells.
| S-EPMC2824783 | biostudies-literature
Project description:Memory T cells exhibit considerable diversity that determines their ability to be protective. Here, we examine whether changes in T cell heterogeneity contribute to the age-associated failure of immune memory. By screening for age-dependent T cell-surface markers, we identify CD4 and CD8 memory T cell subsets that are unrelated to previously defined subsets of central and effector memory cells. Memory T cells expressing the ecto-5'-nucleotidase CD73 constitute a functionally distinct subset of memory T cells that declines with age. They resemble long-lived, polyfunctional memory cells but are also poised to display effector functions and to develop into cells resembling tissue-resident memory T cells (TRMs). Upstream regulators of differential chromatin accessibility and transcriptomes include transcription factors that facilitate CD73 expression and regulate TRM differentiation. CD73 is not just a surrogate marker of these regulatory networks but is directly involved in T cell survival.
| S-EPMC8612175 | biostudies-literature
Project description:A common method used both in vitro and in vivo, to identify Tregs in CD4+ T cells is through the characterization of surface marker CD25. Although CD25 expression is well correlated with regulatory activity in vitro, CD4+CD25+ T cells are not the only regulatory CD4+ T cells in vivo. Studies suggest that in many situations, CD4+CD25M-bM-^@M-^S T cells are as effective as CD4+CD25+ T cells in controlling T cell mediated disease. Therefore, CD25 is not a uniquely specific cell surface marker for the identification of Tregs. CD49f is an M-NM-16-integrin subunit which dimerizes with either the M-NM-2 1 or M-NM-2 4 subunit to form receptors for various laminin isoforms. We found that CD4+ T cells from NOD mice express CD49f, and old non-diabetic NOD mice had an increase of CD4+CD49f+ T cells in the spleen and peripheral lymph node when compared to both young and diabetic mice. This study was conducted to further characterize CD4+CD49f+ Treg cell subpopulation in NOD mice. It was found that CD4+CD49f+T cells possess suppressive ability and only one third of CD4+CD49f+ T cells expressing CD25. Based on the expression of CD49f and CD25, CD4+ T cells was divided into four populations , CD25+CD49f+ ,CD25+CD49f- ,CD25-CD49f+ but CD25-CD49f- are of suppressive ability, and we further found that Foxp3 expression was highly correlated with the suppressive ability of these three Treg populations. In conclusion our data indicate that CD49f marks a CD4+ CD25+ Treg subset with more potent suppression activity and identifies a CD25-CD4+ T cell population with suppression function in a Foxp3+ expression dependent manner. We divided CD4+ T cells into four populations: CD25+CD49f+, CD25+CD49f-, CD25-CD49f+, CD25-CD49f-; Microarray technology was used to determine gene expression differences among these four groups.
2012-05-09 | E-GEOD-30503 | biostudies-arrayexpress
Project description:Recurrence of gastrointestinal adenocarcinomas after surgery and chemotherapy may be attributed, in part, to the presence of a small population of tumor-initiating cancer stem cells (CSC). The expression of galectin-3 (Gal3), a multifunctional oncolectin, has been associated with biological behaviors associated with CSC. We examined the ability of Gal3 to characterize the CSC phenotype, and to identify a clinically important gastrointestinal cancer CSC population. Human colorectal and pancreatic cancer cell lines were sorted to identify subpopulations expressing commonly used CSC markers, and Gal3-positive CSC subpopulations. The association of Gal3 with the stem cell properties and alterations of these phenotypes by manipulation of Gal3 expression was examined. Gastrointestinal cancer cell lines contain both Gal3-positive and Gal3-negative subpopulations. Gal3-positive CSCs are characterized by high ALDH activity, enhanced self-renewal ability in vitro (sphere formation) and tumor forming ability in vivo, and resistance to chemotherapeutic agents and death-receptor-mediated apoptosis compared to Gal3-negative CSCs. Silencing Gal3 modifies this behavior. Cell surface Gal3 expression identifies a subset of CSCs in gastrointestinal cancers with high levels of stem cell characteristics, including chemoresistance. This may provide a platform for developing treatment strategies that target CSC.
| S-EPMC5108324 | biostudies-literature
Project description:Integrin ?(4)?(7) mediates rolling and firm adhesion of leucocytes, two of the critical steps in leukocyte migration and tissue specific homing. Affinity of ?(4)?(7) for ligand is dynamically regulated by three interlinked metal ion-binding sites in ?(7)-subunit I domain. In this study, we found that Phe185 (F185), a highly conserved aromatic residue in ?(7)-subunit, links the specificity-determining loop and the synergistic metal ion-binding site (SyMBS) through cation-? interaction. Mutations of F185 that disrupted the SyMBS cation-F185 interaction led to deficient firm cell adhesion mediated by high affinity ?(4)?(7), and only slightly affected rolling adhesion mediated by low affinity ?(4)?(7). Disruption of SyMBS cation-F185 interaction induced partial extension of integrin ectodomain and separation of cytoplasmic tails, and impaired ?(4)?(7)-mediated bidirectional signaling. In addition, loss of SyMBS cation-F185 interaction increased paxillin expression and promoted paxillin-integrin binding, leading to deficient cell spreading. Furthermore, integrin ?(4)?(7)-mediated cell migration was decreased by the abolishment of SyMBS cation-F185 interaction. Thus, these findings reveal a cation-? interaction playing vital roles in the regulation of integrin affinity, signaling, and biological functions.
| S-EPMC3003088 | biostudies-literature
Project description:HIV-1 persists in cellular reservoirs despite effective antiretroviral therapy (ART). CD4+ T cells are the well-known reservoir, but there is growing evidence that myeloid cells, including circulating monocytes, are also a clinically relevant reservoir. However, it is unclear what are preferentially infected monocyte subsets in vivo. Here, we show that a monocyte fraction expressing the stem cell marker CD34 is more susceptible to HIV-1 infection than the CD34-negative major subset. In ART-untreated viremic patients, CD34+ fraction increased in the percentage in total monocytes, and harbored more proviral DNA than the major subset. Consistent with this, when compared to the major subset, CD34+ fraction expressed HIV-1 receptors (CD4 and CCR5) at higher levels and HIV-1 restriction factors (MX2 and SAMHD1) at lower levels. Interestingly, proviral DNA was detected in CD34+ fraction of ART-treated virologically suppressed patients. CD34+ monocytes were also present in lymph nodes, and expressed CD4 and CCR5 at higher levels than the major subset, as observed for peripheral blood. Moreover, CD34+ monocytes present in peripheral blood and lymph nodes highly expressed CCR7 and sphingosine-1-phosphate receptor 1 (S1PR1), critical regulators of in vivo cellular trafficking. Our findings suggest that circulating CD34+ monocytes are infected with residual HIV-1 after migrating into tissues including lymph nodes and return to circulation, which explains the detection of proviral DNA in the cells even after long-term ART.
2024-01-01 | GSE229346 | GEO
Project description:A common method used both in vitro and in vivo, to identify Tregs in CD4+ T cells is through the characterization of surface marker CD25. Although CD25 expression is well correlated with regulatory activity in vitro, CD4+CD25+ T cells are not the only regulatory CD4+ T cells in vivo. Studies suggest that in many situations, CD4+CD25– T cells are as effective as CD4+CD25+ T cells in controlling T cell mediated disease. Therefore, CD25 is not a uniquely specific cell surface marker for the identification of Tregs. CD49f is an α6-integrin subunit which dimerizes with either the β 1 or β 4 subunit to form receptors for various laminin isoforms. We found that CD4+ T cells from NOD mice express CD49f, and old non-diabetic NOD mice had an increase of CD4+CD49f+ T cells in the spleen and peripheral lymph node when compared to both young and diabetic mice. This study was conducted to further characterize CD4+CD49f+ Treg cell subpopulation in NOD mice. It was found that CD4+CD49f+T cells possess suppressive ability and only one third of CD4+CD49f+ T cells expressing CD25. Based on the expression of CD49f and CD25, CD4+ T cells was divided into four populations , CD25+CD49f+ ,CD25+CD49f- ,CD25-CD49f+ but CD25-CD49f- are of suppressive ability, and we further found that Foxp3 expression was highly correlated with the suppressive ability of these three Treg populations. In conclusion our data indicate that CD49f marks a CD4+ CD25+ Treg subset with more potent suppression activity and identifies a CD25-CD4+ T cell population with suppression function in a Foxp3+ expression dependent manner.
2012-05-10 | GSE30503 | GEO
Project description:CLRs on DCs play important roles in immunity and are expressed selectively on certain DC subsets. Murine DCAL2 (myeloid inhibitory C-type lectin/Clec12a) is a type-II CLR with an ITIM. Using a mouse DCAL2-specific mAb, we found that DCAL2 is expressed at relatively high levels on APCs and that DCAL2 expression can be used to divide CD8α- DCs into DCAL2+DCIR2- and DCAL2-DCIR2+ subpopulations. CD8α-DCAL2+ DC, CD8α-DCIR2+ DC, and CD8α+DCAL2+ DC subsets each express different levels of TLRs and respond to unique classes of TLR ligands by producing distinct sets of cytokines. Whereas CD8α-DCAL2+ DCs robustly produce cytokines, including IL-12, in response to CpG, CD8α-DCIR2+ DCs produce only TNF-α and IL-10 in modest amounts when stimulated with zymosan. However, CD8α-DCIR2+DCs, unlike the other DC subsets, strongly up-regulate OX40L when stimulated with bacterial flagellin. As predicted from their cytokine expression, CD8α-DCAL2+ DCs efficiently induced Th1 responses in the presence of CpG in vitro and in vivo, whereas CD8α-DCIR2+ DCs induced Th2 cells in response to flagellin. Thus, CD8α-DCAL2+ DCs comprise a distinct CD8α- DC subset capable of supporting Th1 responses. DCAL2 is a useful marker to identify a Th1-inducing CD8α- DC population.
| S-EPMC3289397 | biostudies-literature
Project description:Genome-wide expression profiling studies have identified four core molecular subgroups of medulloblastoma: WNT, SHH, Group 3 and Group 4. Molecular markers are necessary for accurate risk stratification in the non-WNT subgroups due to the underlying heterogeneity in genetic alterations and overall survival. MiR-204 expression was evaluated in molecularly classified 260 medulloblastomas from an Indian cohort and in 763 medulloblastomas from the MAGIC cohort, SickKids, Canada. Low expression of miR-204 in the Group 3 / Group 4 tumors identify a highly aggressive subset of tumors having poor overall survival, in the two independent cohorts of medulloblastomas. Downregulation of miR-204 expression correlates with poor survival within the Group 4 as well indicating it as a valuable risk-stratification marker in the subgroup. Restoration of miR-204 expression in multiple medulloblastoma cell lines was found to inhibit their anchorage-independent growth, invasion potential and tumorigenicity. IGF2R was identified as a novel target of miR-204. MiR-204 expression resulted in downregulation of both M6PR and IGF2R that transport lysosomal proteases from the Golgi apparatus to the lysosomes. Consistent with this finding, miR-204 expression resulted in reduction in the levels of the lysosomal proteases in medulloblastoma cells. MiR-204 expression also resulted in inhibition of autophagy that is known to be dependent on the lysosomal degradation pathway and LC3B, a known miR-204 target. Treatment with HDAC inhibitors resulted in upregulation of miR-204 expression in medulloblastoma cells, suggesting therapeutic role for these inhibitors in the treatment of medulloblastomas. In summary, miR-204 is not only a valuable risk stratification marker in the combined cohort of Group 3 / Group 4 medulloblastomas as well as in the Group 4 itself, that has paucity of good prognostication markers, but also has therapeutic potential as indicated by its tumor suppressive effect on medulloblastoma cells.
| S-EPMC6448261 | biostudies-literature
Project description:Selective activity of a specific set of enhancers defines tissue-specific gene transcription. The pioneer factor FOXA1 has been shown to induce functional enhancer competency through chromatin openings. We have previously found that FOXA1 is recruited to thousands of regions across the genome of a given cell type. Here, we monitored the chromatin structure at FOXA1 binding sites on a chromosome-wide scale using formaldehyde assisted isolation of regulatory elements (FAIRE). Surprisingly, we find that a significant fraction of FOXA1-bound sites have a relatively closed chromatin conformation linked to a shift of the epigenetic signature toward repressive histone marks. Importantly, these sites are not correlated with gene expression in a given cell type suggesting that FOXA1 is required, but not sufficient, for the functional activity of bound enhancers. Interestingly, we find that a significant proportion of the inactive FOXA1-bound regulatory sites in one cell type are actually functional in another cellular context. We found that at least half of the FOXA1 binding sites from a given cell type are shared with another cell lineage. Mechanisms that restrict the activity of shared FOXA1-bound enhancers likely play a significant role in defining the cell-type-specific functions of FOXA1.
| S-EPMC2661808 | biostudies-literature