ABSTRACT
Oral epithelia protect against constant challenges by bacteria, viruses, toxins and injury while also contributing to the formation of ectodermal appendages such as teeth, salivary glands and lingual papillae. Despite increasing evidence that differentiation pathway genes are frequently mutated in oral cancers, comparatively little is known about the mechanisms that regulate normal oral epithelial development. Here, we characterize oral epithelial stratification and describe multiple distinct functions for the mitotic spindle orientation gene LGN (Gpsm2) in promoting differentiation and tissue patterning in the mouse oral cavity. Similar to its function in epidermis, apically localized LGN directs perpendicular divisions that promote stratification of the palatal, buccogingival and ventral tongue epithelia. Surprisingly, however, in dorsal tongue LGN is predominantly localized basally, circumferentially or bilaterally and promotes planar divisions. Loss of LGN disrupts the organization and morphogenesis of filiform papillae but appears to be dispensable for embryonic hair follicle development. Thus, LGN has crucial tissue-specific functions in patterning surface ectoderm and its appendages by controlling division orientation.
Subject(s)
Carrier Proteins/metabolism , Epithelium/metabolism , Hair Follicle/embryology , Hair Follicle/metabolism , Animals , Carrier Proteins/genetics , Cell Cycle Proteins , Cell Differentiation/genetics , Cell Differentiation/physiology , Immunohistochemistry , Mice , Microscopy, Electron, Scanning , Morphogenesis/genetics , Morphogenesis/physiology , Signal Transduction/genetics , Signal Transduction/physiology , Taste Buds/embryology , Taste Buds/metabolism , Tongue/embryology , Tongue/metabolismABSTRACT
GATA-3 controls T helper type 2 (TH2) differentiation. However, whether GATA-3 regulates the function of mature T cells beyond TH2 determination remains poorly understood. We found that signaling via the T cell antigen receptor (TCR) and cytokine stimulation promoted GATA-3 expression in CD8(+) T cells, which controlled cell proliferation. Although GATA-3-deficient CD8(+) T cells were generated, their peripheral maintenance was impaired, with lower expression of the receptor for interleukin 7 (IL-7R). GATA-3-deficient T cells had defective responses to viral infection and alloantigen. The proto-oncoprotein c-Myc was a critical target of GATA-3 in promoting T cell proliferation. Our study thus demonstrates an essential role for GATA-3 in controlling the maintenance and proliferation of T cells and provides insight into immunoregulation.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , GATA3 Transcription Factor/immunology , Lymphocyte Activation/immunology , Proto-Oncogene Proteins c-myc/immunology , Receptors, Antigen, T-Cell/immunology , Receptors, Interleukin-7/immunology , Animals , Cell Proliferation , Chromatin Immunoprecipitation , Flow Cytometry , Graft vs Host Disease/immunology , Lymphocytic choriomeningitis virus/immunology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , RNA/chemistry , RNA/genetics , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Establishing a small animal model that accurately recapitulates hepatotropic pathogens, including hepatitis C virus (HCV) infection and immunopathogenesis, is essential for the study of hepatitis virus-induced liver disease and for therapeutics development. This protocol describes our recently developed humanized mouse model for studying HCV and other hepatotropic infections, human immune response and hepatitis and liver fibrosis. The first 5-h stage is the isolation of human liver progenitor and hematopoietic stem cells from fetal liver. Next, AFC8 immunodeficient mice are transplanted with the isolated progenitor/stem cells. This generally takes 2 h. The transplanted mice are then treated for a month with the mouse liver apoptosis-inducing AFC8 dimerizer and left for an additional 2-month period to permit human liver and immune cell growth as well as system reconstitution and development before inoculation with HCV clinical isolates. HCV infection, human immune response and liver disease are observed with high incidence from approximately 2 months after inoculation.
