Project description:Myelin sheath is an important structure to maintain normal functions of the nerves in central nervous system. Protein palmitoylation has been established as a sorting determinant for the transport of myelin-forming proteins to the myelin membrane. However, its function in the regulation of oligodendrocyte development remains unknown. Here, we show that an Asp-His-His-Cys (DHHC) motif-containing palmitoyl acyltransferases, DHHC5, is involved in the control of oligodendrocyte development. Loss of Zdhhc5 in oligodendrocytes inhibits myelination and remyelination by a reduction on total myelinating oligodendrocyte population. STAT3 is the primary substrate for DHHC5 palmitoylation in oligodendrocytes. Zdhhc5 ablation reduces STAT3 palmitoylation, and then suppresses STAT3 phosphorylation and activation. As a result of the decreased STAT3 transactivity, the transcription of the myelin-related and anti-apoptosis genes is therefore inhibited, leading to suppressed oligodendrocyte development and myelination. Our findings demonstrate the key role DHHC5 in the control of myelinogenesis.
Project description:Myelin sheath is an important structure to maintain normal functions of the nerves in central nervous system. Protein palmitoylation has been established as a sorting determinant for the transport of myelin-forming proteins to the myelin membrane. However, its function in the regulation of oligodendrocyte development remains unknown. Here, we show that an Asp-His-His-Cys (DHHC) motif-containing palmitoyl acyltransferases, DHHC5, is involved in the control of oligodendrocyte development. Loss of Zdhhc5 in oligodendrocytes inhibits myelination and remyelination by a reduction on total myelinating oligodendrocyte population. STAT3 is the primary substrate for DHHC5 palmitoylation in oligodendrocytes. Zdhhc5 ablation reduces STAT3 palmitoylation, and then suppresses STAT3 phosphorylation and activation. As a result of the decreased STAT3 transactivity, the transcription of the myelin-related and anti-apoptosis genes is therefore inhibited, leading to suppressed oligodendrocyte development and myelination. Our findings demonstrate the key role DHHC5 in the control of myelinogenesis.
Project description:A mutation in the Signal Transducer and Activator of Transcription 3 (STAT3) has been linked to incidence of Autosomal Dominant Hyper Immunoglobulin E Syndrome (AD-HIES), a disease characterized by elevated serum IgE antibody. However, how this genetic mutation leads to the phenotype has not been fully understood. We investigated the specific role of STAT3 in the germinal center (GC) B cells and plasma cells for IgE class switching. Through the use of STAT3 conditional knockout mice in a Th2-type immunization model, we demonstrated that CD2-Cre driven STAT3 cKO mice showed elevated IgE and decreased IgG1 in the serum, and a reduction in GC formation. Within the GC, IgG1+ GC B cells were decreased while IgE+ GC B cells were more prevalent. Additionally, these mice exhibited reduced IgG1 and elevated IgE populations of antibody-producing plasma cells. Subsequent experiments using a CD19-Cre B-cell specific cKO mouse established this effect to be B-cell intrinsic. Transcription factors critical for GC and plasma cell differentiation, including Bcl-6 and Aicda, were shown to function as downstream signals of STAT3 regulation. Further ChIP-seq analysis revealed that many genes including Bcl3 and Crtc2 were among the direct STAT3 regulated targets. Mice with STAT3 deficiency in B cells also demonstrated an increase in lung inflammation when used in an asthma-like disease model. This model suggests a negative role for STAT3 in regulating class switching of the GC B cells from the IgG1 to the IgE producing state, which may serve as a therapeutic target for treatment of AD-HIES and other immune disorders.
Project description:Activation of JAK-STAT3 signaling by leukemia inhibitory factor (LIF) is required for maintaining self-renewal of mouse embryonic stem cells (mESCs). STAT3 perform cell type-specific roles in different cell type, here we revisit the role of STAT3 using mouse female germ stem cell (mFGSCs). We applied CRISPR/Cas9 system to generate Stat3 knockout FGSCs and then observed cell growth inhibition and cell cycle arrest in KO cell line. By combining genome wide ChIP-Seq and RNA-Seq, we identified 5990 STAT3 binding sites and discovered serval genes specific regulated by STAT3 that were involved in stem cell proliferation and female gonad development in FGSCs. In general, we identify key roles of STAT3 for sustains self-renewal and proliferation for FGSCs in this study.