Estrogen is thought to contribute to the increased frequency of autoimmune disorders occurring in females, but a molecular basis for its effects on autoimmunity remains to be elucidated. We have shown previously that estrogen leads to the survival and activation of autoreactive cells in the naive repertoire. To identify the molecular pathways involved in B cell tolerance, we sought to identify genes that are differentially regulated by estrogen in mouse B cells. Several genes involved in B cell activation and survival, including cd22, shp-1, bcl-2, and vcam-1, were upregulated by estrogen in B cells. We found that overexpression of CD22 and SHP-1 in B cells decreased B cell receptor signaling. Estrogen receptors α and β are expressed on B cells and are functional, since they can directly upregulate expression of CD22, SHP-1, and Bcl-2. Estrogen treatment protected isolated primary B cells from B cell receptor-mediated apoptosis. These results suggest that estrogen induces a genetic program that alters survival and activation of B cells in a B cell-autonomous fashion and thus skews the naive immune system toward autoreactivity.

Estrogen is thought to contribute to the increased frequency of autoimmune disorders occurring in females, but a molecular basis for its effects on autoimmunity remains to be elucidated. We have shown previously that estrogen leads to the survival and activation of autoreactive cells in the naive repertoire. To identify the molecular pathways involved in B cell tolerance, we sought to identify genes that are differentially regulated by estrogen in mouse B cells. Several genes involved in B cell activation and survival, including cd22, shp-1, bcl-2, and vcam-1, were upregulated by estrogen in B cells. We found that overexpression of CD22 and SHP-1 in B cells decreased B cell receptor signaling. Estrogen receptors α and β are expressed on B cells and are functional, since they can directly upregulate expression of CD22, SHP-1, and Bcl-2. Estrogen treatment protected isolated primary B cells from B cell receptor-mediated apoptosis. These results suggest that estrogen induces a genetic program that alters survival and activation of B cells in a B cell-autonomous fashion and thus skews the naive immune system toward autoreactivity.

BackgroundVitiligo is a common skin disorder, characterized by progressive skin de-pigmentation due to the loss of cutaneous melanocytes. The exact cause of melanocyte loss remains unclear, but a large number of observations have pointed to the important role of cellular immunity in vitiligo pathogenesis.Methodology/Principal FindingsIn this study, we characterized T cell and inflammation-related dermal dendritic cell (DC) subsets in pigmented non-lesional, leading edge and depigmented lesional vitiligo skin. By immunohistochemistry staining, we observed enhanced populations of CD11c+ myeloid dermal DCs and CD207+ Langerhans cells in leading edge vitiligo biopsies. DC-LAMP+ and CD1c+ sub-populations of dermal DCs expanded significantly in leading edge and lesional vitiligo skin. We also detected elevated tissue mRNA levels of IL-17A in leading edge skin biopsies of vitiligo patients, as well as IL-17A positive T cells by immunohistochemistry and immunofluorescence. Langerhans cells with activated inflammasomes were also noted in lesional vitiligo skin, along with increased IL-1ß mRNA, which suggest the potential of Langerhans cells to drive Th17 activation in vitiligo.Conclusions/SignificanceThese studies provided direct tissue evidence that implicates active Th17 cells in vitiligo skin lesions. We characterized new cellular immune elements, in the active margins of vitiligo lesions (e.g. populations of epidermal and dermal dendritic cells subsets), which could potentially drive the inflammatory responses.

Metastases from primary cutaneous squamous cell carcinoma (SCC) account for the majority of the ∼10,000 non-melanoma skin cancer deaths in the United States annually. We studied lymphangiogenesis in human SCC because of the potential link to metastasis. SCC samples were stained for lymphatic endothelial vessel marker LYVE-1 and positive cells were counted and compared with cells in normal skin. Gene set enrichment analysis and reverse transcription (RT)-PCR were performed on SCC, on adjacent non-tumor-bearing skin, and on normal skin to determine the differential expression of lymphangiogenesis-associated genes. Laser capture microdissection (LCM) was performed to isolate tumor cells and tumor-associated inflammatory cells for further gene expression analysis. Immunofluorescence was performed to determine the source of vascular endothelial growth factor-C (VEGF-C) in the tumor microenvironment. We found increased lymphatic density and reorganized lymphatic endothelial vessels in the dermis immediately adjacent to SCC nests. RT-PCR confirmed the presence of VEGF-C in skin immediately adjacent to SCC. LCM confirmed the increased expression of VEGF-C, the SCC inflammatory infiltrate. The presence of CD163(+)/CD68(+)/VEGFC(+) cells and absence of VEGF-C expression by CD3(+) or CD11C(+) cells suggested that VEGF-C is derived from tumor-associated macrophages. Clarification of mechanisms governing SCC-mediated lymphangiogenesis may identify potential targets for therapeutic intervention against aggressive or inoperable disease.

In order to determine the phenotype and function of myeloid DCs from human cutaneous squamous cell carcinoma (SCC), we studied their surface marker expression and allo-stimulatory potential ex vivo. There were abundant CD11c+ myeloid DCs, as well as TNF and inducible nitric oxide synthase (iNOS)-producing DCs (TIP-DCs), in and around SCC tumor nests. Although myeloid DCs from SCC, adjacent non-tumor bearing skin, and normal skin, were phenotypically similar by flow cytometry, and there was a pronounced genomic signature of mature DCs in SCC, they showed different T cell stimulatory potential in an allo-MLR. Myeloid DCs from SCC were less potent stimulators of allogeneic T cell proliferation than DCs from non-tumor bearing skin. Culture with a DC-maturing cytokine cocktail (IL-1β, IL-6, TNF, and PGE2) enhanced stimulatory potential in DCs from non-tumor-bearing skin, while SCC associated DCs remained poor stimulators of T cell proliferation. The microenvironment associated with SCC showed expression of TGFβ, IL-10 and VEGF-A, factors capable of suppressing DC function. These findings indicate that CD11c+/HLA-DRhi DCs from SCC are mature, but are not potent stimulators of T cell proliferation compared with phenotypically similar DCs isolated from non-tumor-bearing skin. Identification of mechanisms responsible for suppression of tumor-associated DCs may provide insight into evasion of immunosurveillance by SCC.

Cryptococcus neoformans releases capsular polysaccharide in the supernatant of liquid cultures and in tissues. Significantly less glucuronoxylomannan (GXM) was released by C. neoformans in the presence of capsule-binding monoclonal antibody (MAb). MAb-mediated inhibition of GXM release may be another mechanism by which humoral immunity can mediate protection against this pathogen.

Estrogen is thought to contribute to the increased frequency of autoimmune disorders occurring in females, but a molecular basis for its effects on autoimmunity remains to be elucidated. We have shown previously that estrogen leads to the survival and activation of autoreactive cells in the naive repertoire. To identify the molecular pathways involved in B cell tolerance, we sought to identify genes that are differentially regulated by estrogen in mouse B cells. Several genes involved in B cell activation and survival, including cd22, shp-1, bcl-2, and vcam-1, were upregulated by estrogen in B cells. We found that overexpression of CD22 and SHP-1 in B cells decreased B cell receptor signaling. Estrogen receptors α and β are expressed on B cells and are functional, since they can directly upregulate expression of CD22, SHP-1, and Bcl-2. Estrogen treatment protected isolated primary B cells from B cell receptor-mediated apoptosis. These results suggest that estrogen induces a genetic program that alters survival and activation of B cells in a B cell-autonomous fashion and thus skews the naive immune system toward autoreactivity.

Breast cancer has the second highest death toll in women worldwide, despite significant progress in early diagnosis and treatments. The main cause of death is metastatic disease. Matrix metalloproteinases (MMPs) are required for the initial steps of metastasis, and have therefore been considered as ideal pharmacological targets for anti-metastatic therapy. However, clinical trials of MMP inhibitors were unsuccessful. These trials were conducted in patients with advanced disease, beyond the stage when these compounds could have been effective. We hypothesized that early treatment with a selective MMP inhibitor between the time of diagnosis and definitive surgery, the so-called “window-of-opportunity,” can inhibit metastasis and thereby improve survival. To investigate our hypothesis we used the 4T1 mouse model of aggressive mammary carcinoma. We treated the animals with SD-7300, an oral inhibitor of MMP-2, -9 and -13, starting after the initial detection of the primary tumor. Seven days later the primary tumors were excised and analyzed for MMP activity, and the SD-7300 treatment was discontinued. After four weeks the animals were sacrificed and their lungs analyzed histologically for number of metastases and metastatic burden (metastases’ area/lung section area). SD-7300 treatment inhibited 70–80% of tumor-associated MMP activity (P = 0.0003), reduced metastasis number and metastatic burden by 50–60% (P = 0.002; P = 0.0082, respectively), and increased survival (92% vs. 66.7%; P = 0.0409), relative to control vehicle. These results show that treatment of early invasive breast cancer with selective MMP inhibitors can lower the risk of recurrence and increase long-term disease-free survival.