Single-cell Profiles and Prognostic Impact of Tumor-Infiltrating Lymphocytes Coexpressing CD39, CD103, and PD-1 in Ovarian Cancer.

PURPOSE: Tumor-infiltrating lymphocytes (TIL) are strongly associated with survival in most cancers; however, the tumor-reactive subset that drives this prognostic effect remains poorly defined. CD39, CD103, and PD-1 have been independently proposed as markers of tumor-reactive CD8+ TIL in various cancers. We evaluated the phenotype, clonality, and prognostic significance of TIL expressing various combinations of these markers in high-grade serous ovarian cancer (HGSC), a malignancy in need of more effective immunotherapeutic approaches. EXPERIMENTAL DESIGN: Expression of CD39, CD103, PD-1, and other immune markers was assessed by high-dimensional flow cytometry, single-cell sequencing, and multiplex immunofluorescence of primary and matched pre/post-chemotherapy HGSC specimens. RESULTS: Coexpression of CD39, CD103, and PD-1 ("triple-positive" phenotype) demarcated subsets of CD8+ TIL and CD4+ regulatory T cells (Treg) with a highly activated/exhausted phenotype. Triple-positive CD8+ TIL exhibited reduced T-cell receptor (TCR) diversity and expressed genes involved in both cytolytic and humoral immunity. Triple-positive Tregs exhibited higher TCR diversity and a tumor-resident phenotype. Triple-positive TIL showed superior prognostic impact relative to TIL expressing other combinations of these markers. TIGIT was uniquely upregulated on triple-positive CD8+ effector cells relative to their CD4+ Treg counterparts. CONCLUSIONS: Coexpression of CD39, CD103, and PD-1 demarcates highly activated CD8+ and CD4+ TIL with inferred roles in cytolytic, humoral, and regulatory immune functions. Triple-positive TIL demonstrate exceptional prognostic significance and express compelling targets for combination immunotherapy, including PD-1, CD39, and TIGIT.

Expression pattern of tissue-resident memory T cells in cutaneous lupus erythematosus.

BACKGROUND: Tissue resident memory T cells (TRMs) persist long-term in peripheral tissues without recirculation, triggering an immediate protective inflammatory state upon the re-recognition of the antigen. Despite evidence incriminating the dysregulation of TRMs in autoimmune diseases, few studies have examined their expression in cutaneous lupus erythematosus (CLE). OBJECTIVES: We aimed to examine whether there are differences among TRM populations in CLE depending on different clinical conditions, such as the CLE subtype or association with systemic lupus erythematosus, and to determine the effect of type I interferon (IFN) on the development of TRMs in CLE. METHODS: CLE disease activity was evaluated using the Cutaneous Lupus Erythematosus Disease Area and Severity Index. The expression of the TRM markers CD69 and CD103 in CLE lesions was evaluated by immunofluorescence. Flow cytometry was performed on peripheral blood mononuclear cells after IFNα treatment. RESULTS: The number of TRMs expressing either CD69 or CD103 was significantly higher in CLE lesions than in control skin; however, it was not significantly different between discoid lupus erythematosus and subacute CLE, or dependent on the presence of concomitant systemic lupus. Lesional severity was not correlated with an increase in TRMs in CLE. IFNα treatment induced a conspicuous increase in CD69 expression in skin-homing T cells, more profoundly in CD4+ T cells than in CD8+ T cells. CONCLUSIONS: Skin TRMs, either CD69 or CD103-positive cells, showed increased levels in the lesional skin of CLE, and IFNα increased the expression of CD69 in T cells.

Integrin α2ß1 plays an important role in the interaction between human articular cartilage-derived chondrocytes and atelocollagen gel.

Although atelocollagen gel is used as a scaffold for culturing human articular cartilage-derived chondrocytes, little is known about cell-gel interactions. In this study, we investigated the mechanism via which atelocollagen gel affects human articular cartilage-derived chondrocytes. Two types of three-dimensional cultures of human articular cartilage-derived chondrocytes (i.e., with and without atelocollagen gel) were compared. While the amount of atelocollagen gel in culture gradually decreased with time, it promoted the expression of matrix metalloproteinases (MMPs) during the early stages of culture. Genome-wide differential gene expression analysis revealed that cell membrane- and extracellular matrix-related genes were highly ranked among up- and down-regulated groups in cells cultured in the presence of atelocollagen gel. Among the integrin family of genes, the expression of integrin subunit alpha 2 and integrin subunit alpha 10 was significantly increased in the presence of atelocollagen gel. Blocking α2ß1 integrin with the specific inhibitor BTT 3033 had a significant effect on cell proliferation, MMP expression, and cell shape, as well as on the response to mechanical stimulation. Taken together, our findings indicate that the α2ß1 integrin pathway plays an important role in the interaction of atelocollagen gel with human articular cartilage-derived chondrocytes and may be a potential therapeutic target for articular cartilage disorders.

The autophagy protein Ambra1 regulates gene expression by supporting novel transcriptional complexes.

Ambra1 is considered an autophagy and trafficking protein with roles in neurogenesis and cancer cell invasion. Here, we report that Ambra1 also localizes to the nucleus of cancer cells, where it has a novel nuclear scaffolding function that controls gene expression. Using biochemical fractionation and proteomics, we found that Ambra1 binds to multiple classes of proteins in the nucleus, including nuclear pore proteins, adaptor proteins such as FAK and Akap8, chromatin-modifying proteins, and transcriptional regulators like Brg1 and Atf2. We identified biologically important genes, such as Angpt1, Tgfb2, Tgfb3, Itga8, and Itgb7, whose transcription is regulated by Ambra1-scaffolded complexes, likely by altering histone modifications and Atf2 activity. Therefore, in addition to its recognized roles in autophagy and trafficking, Ambra1 scaffolds protein complexes at chromatin, regulating transcriptional signaling in the nucleus. This novel function for Ambra1, and the specific genes impacted, may help to explain the wider role of Ambra1 in cancer cell biology.

Integrin α11ß1 is expressed in breast cancer stroma and associates with aggressive tumor phenotypes.

Cancer-associated fibroblasts are essential modifiers of the tumor microenvironment. The collagen-binding integrin α11ß1 has been proposed to be upregulated in a pro-tumorigenic subtype of cancer-associated fibroblasts. Here, we analyzed the expression and clinical relevance of integrin α11ß1 in a large breast cancer series using a novel antibody against the human integrin α11 chain. Several novel monoclonal antibodies against the integrin α11 subunit were tested for use on formalin-fixed paraffin-embedded tissues, and Ab 210F4B6A4 was eventually selected to investigate the immunohistochemical expression in 392 breast cancers using whole sections. mRNA data from METABRIC and co-expression patterns of integrin α11 in relation to αSMA and cytokeratin-14 were also investigated. Integrin α11 was expressed to varying degrees in spindle-shaped cells in the stroma of 99% of invasive breast carcinomas. Integrin α11 co-localized with αSMA in stromal cells, and with αSMA and cytokeratin-14 in breast myoepithelium. High stromal integrin α11 expression (66% of cases) was associated with aggressive breast cancer features such as high histologic grade, increased tumor cell proliferation, ER negativity, HER2 positivity, and triple-negative phenotype, but was not associated with breast cancer specific survival at protein or mRNA levels. In conclusion, high stromal integrin α11 expression was associated with aggressive breast cancer phenotypes.

Forkhead box C1 promotes colorectal cancer metastasis through transactivating ITGA7 and FGFR4 expression.

Metastatic colorectal cancer (CRC) is one of the most common causes of cancer death worldwide; however, the molecular mechanism underlying CRC metastasis remains unknown. Using an integrated approach, we identified forkhead box C1 (FOXC1) as a novel regulator of CRC metastasis. Elevated expression of FOXC1 is significantly correlated with metastasis, recurrence and reduced survival. FOXC1 overexpression promotes CRC invasion and lung metastasis, whereas FOXC1 knockdown has the opposite effect. In addition, FOXC1 directly binds its target genes integrin α7 (ITGA7) and fibroblast growth factor receptor 4 (FGFR4) and activates their expression. Genetic epistasis analysis confirmed that ITGA7 and FGFR4 act downstream of FOXC1. Furthermore, pharmaceutical inhibition of FGFR4 can reverse CRC metastasis mediated by FOXC1 overexpression. These results suggest that FOXC1 is a prognostic biomarker in CRC patients and targeting the FGFR4 signaling pathway may provide a promising strategy for the treatment of FOXC1-driven CRC metastasis.

TCR-pMHC encounter differentially regulates transcriptomes of tissue-resident CD8 T cells.

To investigate the role of TCR-pMHC interaction in regulating lung CD8 tissue-resident T cell (TR ) differentiation, polyclonal responses were compared against NP366-374 /Db and PA224-233 /Db , two immunodominant epitopes that arise during influenza A infection in mice. Memory niches distinct from iBALTs develop within the lamina propria, supporting CD103+ and CD103- CD8 TR generation and intraepithelial translocation. Gene set enrichment analysis (GSEA) and weighted gene co-expression network analysis (WGCNA) identify dominant TCR, adherens junction, RIG-I-like and NOD-like pattern recognition receptor as well as TGF-ß signaling pathways and memory signatures among PA224-233 /Db T cells consistent with T resident memory (TRM ) status. In contrast, NP366-374 /Db T cells exhibit enrichment of effector signatures, upregulating pro-inflammatory mediators even among TRM . While NP366-374 /Db T cells manifest transcripts linked to canonical exhaustion pathways, PA224-233 /Db T cells exploit P2rx7 purinoreceptor attenuation. The NP366-374 /Db CD103+ subset expresses the antimicrobial lactotransferrin whereas PA224-233 /Db CD103+ utilizes pore-forming mpeg-1, with <22% of genes correspondingly upregulated in CD103+ (or CD103- ) subsets of both specificities. Thus, TCR-pMHC interactions among TR and antigen presenting cells in a tissue milieu strongly impact CD8 T cell biology.

Integrin alpha 10, CD44, PTEN, cadherin-11 and lactoferrin expressions are potential biomarkers for selecting patients in need of central nervous system prophylaxis in diffuse large B-cell lymphoma.

Central nervous system (CNS) relapse is a devastating complication that occurs in about 5% of diffuse large B-cell lymphoma (DLBCL) patients. Currently, there are no predictive biological markers. We wanted to study potential biomarkers of CNS tropism that play a role in adhesion, migration and/or in the regulation of inflammatory responses. The expression levels of ITGA10, CD44, PTEN, cadherin-11, CDH12, N-cadherin, P-cadherin, lactoferrin and E-cadherin were studied with IHC and IEM. GEP was performed to see whether found expressional changes are regulated at DNA/RNA level. IHC included 96 samples of primary CNS lymphoma (PCNSL), secondary CNS lymphoma (sCNSL) and systemic DLBCL (sDLBCL). IEM included two PCNSL, one sCNSL, one sDLBCL and one reactive lymph node samples. GEP was performed on two DLBCL samples, one with and one without CNS relapse. CNS disease was associated with enhanced expression of cytoplasmic and membranous ITGA10 and nuclear PTEN (P < 0.0005, P = 0.002, P = 0.024, respectively). sCNSL presented decreased membranous CD44 and nuclear and cytoplasmic cadherin-11 expressions (P = 0.001, P = 0.006, P = 0.048, respectively). In PCNSL lactoferrin expression was upregulated (P < 0.0005). IEM results were mainly supportive of the IHC results. In GEP CD44, cadherin-11, lactoferrin and E-cadherin were under-expressed in CNS disease. Our results are in line with previous studies, where gene expressions in extracellular matrix and adhesion-related pathways are altered in CNS lymphoma. This study gives new information on the DLBCL CNS tropism. If further verified, these markers might become useful in predicting CNS relapses.

Prognostic implications of intratumoral CD103+ tumor-infiltrating lymphocytes in pulmonary squamous cell carcinoma.

CD103 is the αE subunit of αEß7 integrin that is expressed in tissue-resident memory T cells, where it promotes cytotoxic T cell responses against tumors. However, little is known about its expression or clinicopathological implications in non-small cell lung cancer (NSCLC). This study investigated the prognostic implications of CD103+ tumor-infiltrating lymphocytes (TILs) in NSCLC. We established two cohorts: patients with resected NSCLC (n = 132) and patients with pulmonary squamous cell carcinoma (pSCC), a subset of NSCLC (n = 378), to estimate the prognostic significance of CD103+ TILs. The numbers of CD103+ TILs in the intratumoral (i.e., intraepithelial) and stromal regions of NSCLC were estimated using immunohistochemistry and automated image analysis. In the NSCLC cohort, high numbers of intratumoral CD103+ TILs were significantly associated with prolonged disease-free survival (DFS) and overall survival (OS) in patients with pSCC but not in those with pulmonary adenocarcinoma. In the pSCC cohort, a positive correlation was observed between the numbers of intratumoral CD103+ and CD8+ TILs (correlation coefficient = 0.736, P < 0.001). The ratio of intratumoral/stromal CD103+ TILs was higher in pSCC with high compared to low E-cadherin expression (P = 0.021). According to Kaplan-Meier analysis, high intratumoral but not stromal CD103+ TILs were associated with prolonged DFS and OS in patients with resected pSCC (P = 0.021 and 0.002, respectively). Multivariate analysis revealed that a high number of intratumoral CD103+ TILs is an independent predictor of a more favorable DFS (P = 0.021). Thus, a high number of intratumoral CD103+ TILs is a favorable prognostic indicator in patients with pSCC.

Highly Expressed Integrin-α8 Induces Epithelial to Mesenchymal Transition-Like Features in Multiple Myeloma with Early Relapse.

Despite recent groundbreaking advances in multiple myeloma (MM) treatment, most MM patients ultimately experience relapse, and the relapse biology is not entirely understood. To define altered gene expression in MM relapse, gene expression profiles were examined and compared among 16 MM patients grouped by 12 months progression-free survival (PFS) after autologous stem cell transplantation. To maximize the difference between prognostic groups, patients at each end of the PFS spectrum (the four with the shortest PFS and four with the longest PFS) were chosen for additional analyses. We discovered that integrin-α8 (ITGA8) is highly expressed in MM patients with early relapse. The integrin family is well known to be involved in MM progression; however, the role of integrin-α8 is largely unknown. We functionally overexpressed integrin-α8 in MM cell lines, and surprisingly, stemness features including HIF1α, VEGF, OCT4, and Nanog, as well as epithelial mesenchymal transition (EMT)-related phenotypes, including N-cadherin, Slug, Snail and CXCR4, were induced. These, consequently, enhanced migration and invasion abilities, which are crucial to MM pathogenesis. Moreover, the gain of integrin-α8 expression mediated drug resistance against melphalan and bortezomib, which are the main therapeutic agents in MM. The cBioPortal genomic database revealed that ITGA8 have significant tendency to co-occur with PDGFRA and PDGFRB and their mRNA expression were up-regulated in ITGA8 overexpressed MM cells. In summary, integrin-α8, which was up-regulated in MM of early relapse, mediates EMT-like phenotype, enhancing migration and invasion; therefore, it could serve as a potential marker of MM relapse and be a new therapeutic target.

High Expression of Intestinal Homing Receptor CD103 in Adult T-Cell Leukemia/Lymphoma, Similar to 2 Other CD8+ T-Cell Lymphomas.

We investigated the expression of the αEß7 integrin (CD103)-intestinal homing receptor of T-intraepithelial lymphocytes (IELs) in 130 cases of adult T-cell leukemia/lymphoma (ATLL). We detected CD103 lymphoma cells in 55% (31/56) of mainly gastrointestinal (GI)-involved ATLL cases. Among them, lymphoma cells of 18 cases located in other involved organs had similar CD103 expression patterns. Histologically, we found (a) increased reactive IELs in non-neoplastic mucosal layers in 28% (5/18) of surgical and mucosal resection cases, (b) preserved epithelial glands, and (c) numerous small intraepithelial ATLL nests in involved lesions in 36 (69%) and 21 (40%), respectively, of the 52 examined cases. These 3 patterns were common in intestinal type II enteropathy-associated T-cell lymphoma but were rare in intestinal EBV nasal-type/like T/natural killer (NK)-cell lymphoma. We detected CD103 tumor cells in 41% (16/39) of lymph node-involved ATLL, in 31% (11/35) of skin-involved ATLL, in 68% (21/31) of type II CD4 enteropathy-associated T-cell lymphoma cases, in 36% (8/22) of primary gastric T/NK-cell lymphomas, and in 77% (7/9) of CD8 epidermotropic mycosis fungoides. CD103 ATLL prefers involving the GI tract over the skin (P<0.05). CD103 expression in GI-involved and/or total ATLL cases was significantly higher than in other 9 T/NK-cell lymphoma groups (P<0.05 or 0.01). Only ATLL cases were commonly CD103 in CD4 T/NK-cell lymphoma groups (P<0.05 or 0.01). Human T-lymphotropic virus-1-infected CD103 T-IELs and mucosal T cells may be important sources of ATLL.

Expression of α5-integrin, α7-integrin, Ε-cadherin, and N-cadherin in localized prostate cancer.

OBJECTIVE: To explore the correlation between the expression of α5-integrin, α7-integrin, Ε-cadherin, and N-cadherin in prostate cancer (PCa) and its clinicopathological data including tumor grade and clinical stage. METHODS: The expression of α5-integrin, α7-integrin, Ε-cadherin, and N-cadherin was examined in 157 cases of PCa and adjacent normal prostatic tissue by immunohistochemical assay, and the correlation with clinicopathological features was analyzed. RESULTS: Expressions of α5-integrin, α7-integrin, and Ε-cadherin in PCa were lower than those in normal prostatic tissues (P<0.05). N-cadherin expression was higher in cancer prostatic tissue than in normal prostatic tissues (P<0.05). The reduced expression of α5-integrin, α7-integrin, and Ε-cadherin was related to Gleason score, pathological stage, lymph node metastasis, and prostate-specific antigen level, but it was not associated with positive surgical margins and patient age. The increased expression of N-cadherin was related to Gleason score, pathological stage, lymph node metastasis, and prostate-specific antigen level, but not to age and positive surgical margins. The expression of E-cadherin was highly negatively correlated with that of N-cadherin and also positively correlated with that of α5-integrin and α7-integrin. CONCLUSION: The reduced expression of α5-integrin, α7-integrin, and Ε-cadherin and abnormal expression of N-cadherin play an important role in the occurrence and development of PCa. The results indicate that these have potential values in the diagnosis and are predictable indices in the proliferation of PCa.

Impact of Toxoplasma gondii on Dendritic Cell Subset Function in the Intestinal Mucosa.

The function of mucosal dendritic cell (DC) subsets in immunity and inflammation is not well understood. In this study, we define four DC subsets present within the lamina propria and mesenteric lymph node compartments based on expression of CD103 and CD11b. Using IL-12p40 YFP (Yet40) reporter mice, we show that CD103(+)CD11b(-) mucosal DCs are primary in vivo sources of IL-12p40; we also identified CD103(-)CD11b(-) mucosal DCs as a novel population producing this cytokine. Infection was preferentially found in CD11b(+) DCs that were negative for CD103. Lamina propria DCs containing parasites were negative for IL-12p40. Instead, production of the cytokine was strictly a property of noninfected cells. We also show that vitamin A metabolism, as measured by ALDH activity, was preferentially found in CD103(+)CD11b(+) DC and was strongly downregulated in all mucosal DC subsets during infection. Finally, overall apoptosis of lamina propria DC subsets was increased during infection. Combined, these results highlight the ability of intestinal Toxoplasma infection to alter mucosal DC activity at both the whole population level and at the level of individual subsets.

MyD88 Signaling Regulates Steady-State Migration of Intestinal CD103+ Dendritic Cells Independently of TNF-α and the Gut Microbiota.

Intestinal homeostasis and induction of systemic tolerance to fed Ags (i.e., oral tolerance) rely on the steady-state migration of small intestinal lamina propria dendritic cells (DCs) into draining mesenteric lymph nodes (MLN). The majority of these migratory DCs express the α integrin chain CD103, and in this study we demonstrate that the steady-state mobilization of CD103(+) DCs into the MLN is in part governed by the IL-1R family/TLR signaling adaptor molecule MyD88. Similar to mice with complete MyD88 deficiency, specific deletion of MyD88 in DCs resulted in a 50-60% reduction in short-term accumulation of both CD103(+)CD11b(+) and CD103(+)CD11b(-) DCs in the MLN. DC migration was independent of caspase-1, which is responsible for the inflammasome-dependent proteolytic activation of IL-1 cytokine family members, and was not affected by treatment with broad-spectrum antibiotics. Consistent with the latter finding, the proportion and phenotypic composition of DCs were similar in mesenteric lymph from germ-free and conventionally housed mice. Although TNF-α was required for CD103(+) DC migration to the MLN after oral administration of the TLR7 agonist R848, it was not required for the steady-state migration of these cells. Similarly, TLR signaling through the adaptor molecule Toll/IL-1R domain-containing adapter inducing IFN-ß and downstream production of type I IFN were not required for steady-state CD103(+) DC migration. Taken together, our results demonstrate that MyD88 signaling in DCs, independently of the microbiota and TNF-α, is required for optimal steady-state migration of small intestinal lamina propria CD103(+) DCs into the MLN.

Human α7 Integrin Gene (ITGA7) Delivered by Adeno-Associated Virus Extends Survival of Severely Affected Dystrophin/Utrophin-Deficient Mice.

Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene. It is the most common, severe childhood form of muscular dystrophy. We investigated an alternative to dystrophin replacement by overexpressing ITGA7 using adeno-associated virus (AAV) delivery. ITGA7 is a laminin receptor in skeletal muscle that, like the dystrophin-glycoprotein complex, links the extracellular matrix to the internal actin cytoskeleton. ITGA7 is expressed in DMD patients and overexpression does not elicit an immune response to the transgene. We delivered rAAVrh.74.MCK.ITGA7 systemically at 5-7 days of age to the mdx/utrn(-/-) mouse deficient for dystrophin and utrophin, a severe mouse model of DMD. At 8 weeks postinjection, widespread expression of ITGA7 was observed at the sarcolemma of multiple muscle groups following gene transfer. The increased expression of ITGA7 significantly extended longevity and reduced common features of the mdx/utrn(-/-) mouse, including kyphosis. Overexpression of α7 expression protected against loss of force following contraction-induced damage and increased specific force in the diaphragm and EDL muscles 8 weeks after gene transfer. Taken together, these results further support the use of α7 integrin as a potential therapy for DMD.

Cisplatin at sub-toxic levels mediates integrin switch in lung cancer cells.

BACKGROUND: Resistance to chemotherapeutic agents, as well as enhanced metastasis, have been frequently reported in lung cancer. MATERIALS AND METHODS: Cytotoxicity and proliferative effects of cisplatin on H460 lung cancer cells were evaluated by the MTT assay. Migration capacity was evaluated by the wound healing assay. The number of filopodia per cell were detected by rhodamine-phalloidin staining assay. The changes of protein levels of integrins, and migration-related proteins in response to cisplatin at sub-toxic concentrations were determined by western blotting. RESULTS: Herein we demonstrate for the first time that exposure to low concentrations of cisplatin results in increase of cell motility with the alteration of integrin expression. Cisplatin-treated cells exhibited a significant increase in the number of filopodia per cell in correlation with enhanced migration. Migration regulatory proteins, namely activated forms of focal-adhesion kinase (FAK) and ATP-dependent tyrosine kinase (AKT), were found to significantly be up-regulated in cisplatin-treated cells in comparison to those of the non-treated control. Active Rho A-GTP and Rac-GTP were found to be increased in accordance with activation of FAK/AKT signals. Furthermore, we found that such migration enhancement may be in part due to the integrin switch mediated by cisplatin treatment. Cisplatin induced a dramatic alteration in the integrin expression pattern by up-regulating integrin α4, αv, ß1, and ß5 which were previously reported to increase cell motility, while it had no effect on integrin α5, and ß3. CONCLUSION: As the integrin switch is a hallmark of highly aggressive cancer, these findings may provide insights for better understanding of cancer cell adaptation after exposure to cisplatin.

A minor subset of Batf3-dependent antigen-presenting cells in islets of Langerhans is essential for the development of autoimmune diabetes.

Autoimmune diabetes is characterized by inflammatory infiltration; however, the initiating events are poorly understood. We found that the islets of Langerhans in young nonobese diabetic (NOD) mice contained two antigen-presenting cell (APC) populations: a major macrophage and a minor CD103(+) dendritic cell (DC) population. By 4 weeks of age, CD4(+) T cells entered islets coincident with an increase in CD103(+) DCs. In order to examine the role of the CD103(+) DCs in diabetes, we examined Batf3-deficient NOD mice that lacked the CD103(+) DCs in islets and pancreatic lymph nodes. This led to a lack of autoreactive T cells in islets and, importantly, no incidence of diabetes. Additional examination revealed that presentation of major histocompatibility complex (MHC) class I epitopes in the pancreatic lymph nodes was absent with a partial impairment of MHC class II presentation. Altogether, this study reveals that CD103(+) DCs are essential for autoimmune diabetes development.

Leukocyte ß7 integrin targeted by Krüppel-like factors.

Constitutive expression of Krüppel-like factor 3 (KLF3, BKLF) increases marginal zone (MZ) B cell numbers, a phenotype shared with mice lacking KLF2. Ablation of KLF3, known to interact with serum response factor (SRF), or SRF itself, results in fewer MZ B cells. It is unknown how these functional equivalences result. In this study, it is shown that KLF3 acts as transcriptional repressor for the leukocyte-specific integrin ß7 (Itgb7, Ly69) by binding to the ß7 promoter, as revealed by chromatin immunoprecipitation. KLF2 overexpression antagonizes this repression and also binds the ß7 promoter, indicating that these factors may compete for target sequence(s). Whereas ß7 is identified as direct KLF target, its repression by KLF3 is not connected to the MZ B cell increase because ß7-deficient mice have a normal complement of these and the KLF3-driven increase still occurs when ß7 is deleted. Despite this, KLF3 overexpression abolishes lymphocyte homing to Peyer's patches, much like ß7 deficiency does. Furthermore, KLF3 expression alone overcomes the MZ B cell deficiency when SRF is absent. SRF is also dispensable for the KLF3-mediated repression of ß7. Thus, despite the shared phenotype of KLF3 and SRF-deficient mice, cooperation of these factors appears neither relevant for the formation of MZ B cells nor for the regulation of ß7. Finally, a potent negative regulatory feedback loop limiting KLF3 expression is shown in this study, mediated by KLF3 directly repressing its own gene promoter. In summary, KLFs use regulatory circuits to steer lymphocyte maturation and homing and directly control leukocyte integrin expression.

Mesenchymal precursor cells maintain the differentiation and proliferation potentials of breast epithelial cells.

INTRODUCTION: Stromal-epithelial interactions play a fundamental role in tissue homeostasis, controlling cell proliferation and differentiation. Not surprisingly, aberrant stromal-epithelial interactions contribute to malignancies. Studies of the cellular and molecular mechanisms underlying these interactions require ex vivo experimental model systems that recapitulate the complexity of human tissue without compromising the differentiation and proliferation potentials of human primary cells. METHODS: We isolated and characterized human breast epithelial and mesenchymal precursors from reduction mammoplasty tissue and tagged them with lentiviral vectors. We assembled heterotypic co-cultures and compared mesenchymal and epithelial cells to cells in corresponding monocultures by analyzing growth, differentiation potentials, and gene expression profiles. RESULTS: We show that heterotypic culture of non-immortalized human primary breast epithelial and mesenchymal precursors maintains their proliferation and differentiation potentials and constrains their growth. We further describe the gene expression profiles of stromal and epithelial cells in co-cultures and monocultures and show increased expression of the tumor growth factor beta (TGFß) family member inhibin beta A (INHBA) in mesenchymal cells grown as co-cultures compared with monocultures. Notably, overexpression of INHBA in mesenchymal cells increases colony formation potential of epithelial cells, suggesting that it contributes to the dynamic reciprocity between breast mesenchymal and epithelial cells. CONCLUSIONS: The described heterotypic co-culture system will prove useful for further characterization of the molecular mechanisms mediating interactions between human normal or neoplastic breast epithelial cells and the stroma, and will provide a framework to test the relevance of the ever-increasing number of oncogenomic alterations identified in human breast cancer.

Oral infection drives a distinct population of intestinal resident memory CD8(+) T cells with enhanced protective function.

The intestinal mucosa promotes T cell responses that might be beneficial for effective mucosal vaccines. However, intestinal resident memory T (Trm) cell formation and function are poorly understood. We found that oral infection with Listeria monocytogenes induced a robust intestinal CD8 T cell response and blocking effector T cell migration showed that intestinal Trm cells were critical for secondary protection. Intestinal effector CD8 T cells were predominately composed of memory precursor effector cells (MPECs) that rapidly upregulated CD103, which was needed for T cell accumulation in the intestinal epithelium. CD103 expression, rapid MPEC formation, and maintenance in intestinal tissues were dependent on T cell intrinsic transforming growth factor ß signals. Moreover, intestinal Trm cells generated after intranasal or intravenous infection were less robust and phenotypically distinct from Trm cells generated after oral infection, demonstrating the critical contribution of infection route for directing the generation of protective intestinal Trm cells.