Browsing by Author "Liang, Jie"
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Item Open Access Dendritic cells in the intestine: sensing of microbiota and inducing of inflammatory bowel disease(2017) Liang, JieDendritic cells (DCs) are potent antigen presenting cells (APC) that sense microbes and induce T cell activation and functional differentiation. The APC function of DCs is upregulated by the signaling pathway downstream of the microbial sensing receptor, a process well studied during pathogen infection and immunization. Multiple lines of evidence suggested that DCs in the intestine lamina propria (LP-DCs) frequently interact with the innocuous microbiota, and through these interactions LP-DCs support intestinal immune homeostasis. However, DC responses to microbiota, if not regulated, can give rise to inflammatory T cells and trigger inflammatory bowel disease (IBD). The DC subsets, DC functions and signaling pathways that induce inflammatory T cells remain incompletely characterized. Here, we demonstrated that mice lacking signaling attenuator A20 (A20cko mice) in DCs develop spontaneous small intestine inflammation that is dependent of microbiota, DCs and T cells. LP-DCs induce inflammatory T cells and that the signals perceived and APC functions are unique for three distinct LP-DC subsets. Thus, while CD103+CD11b- DCs exclusively upregulate their ability to instruct IFNγ+ T cells, CD103+CD11b+ DCs exclusively upregulate their ability to instruct IL-17+ T cells. Of note, APC functions of both DC subsets are upregulated in a MyD88-independent fashion. In contrast, CD103-CD11b+ DCs instruct both IFNγ+ and IL-17+ T cells, and only the IL-17-inducing APC functions require MyD88. In disease pathogenesis, both CD103-CD11b+ and CD103+CD11b+ DCs expand pathologic Th17 cells.
Although MyD88 pathways are potent inducer of intestinal inflammation in the colitis of IL-10 knockout mice and upon transferring of naïve T cells into Rag-deficient hosts, MyD88 pathways are not required for the inflammation of small intestine in A20cko mice. Among the MyD88-independent signaling pathways that could mediate host interaction with microbiota, Dectin-1 pathway is of particular interest because both the receptor Dectin-1 and the downstream signaling molecule CARD9 are IBD-associated genes. Additionally, the defect in either molecule influences the severity of the intestinal inflammation in mouse. We established that the production of inflammatory cytokines downstream of the Dectin-1 pathway is restricted by A20. Mechanistically, A20 inhibits TRAF6 ubiquitination downstream of the Dectin-1 pathway, thereby controlling NFκB and Jnk activation. Although we showed that CD103-CD11b+ and CD103+CD11b+ DCs express Dectin-1 and CARD9, the Dectin-1 pathway is not required for the upregulation of DC function and expansion of inflammatory T cells in the intestine of A20cko mice. Thus, our studies have unveiled a critical role of MyD88-independent pathways in mediating the interaction of the microbiota and LP-DCs. MyD88-independent pathway is capable of driving functional maturation of LP-DCs, pathological expansion of CD4 T cells, and the inflammatory disease in the small intestine.
Item Open Access Inflammatory Th1 and Th17 in the Intestine Are Each Driven by Functionally Specialized Dendritic Cells with Distinct Requirements for MyD88.(Cell Rep, 2016-10-25) Liang, Jie; Huang, Hsin-I; Benzatti, Fernanda P; Karlsson, Amelia B; Zhang, Junyi J; Youssef, Nourhan; Ma, Averil; Hale, Laura P; Hammer, Gianna ENormal dynamics between microbiota and dendritic cells (DCs) support modest numbers of T cells, yet these do not cause inflammation. The DCs that induce inflammatory T cells and the signals that drive this process remain unclear. Here, we demonstrate that small intestine DCs lacking the signaling attenuator A20 induce inflammatory T cells and that the signals perceived and antigen-presenting cell (APC) functions are unique for different DC subsets. Thus, although CD103(+)CD11b(-) DCs exclusively instruct IFNγ(+) T cells, CD103(+)CD11b(+) DCs exclusively instruct IL-17(+) T cells. Surprisingly, APC functions of both DC subsets are upregulated in a MyD88-independent fashion. In contrast, CD103(-)CD11b(+) DCs instruct both IFNγ(+) and IL-17(+) T cells, and only the IL-17-inducing APC functions require MyD88. In disease pathogenesis, both CD103(-)CD11b(+) and CD103(+)CD11b(+) DCs expand pathologic Th17 cells. Thus, in disease pathogenesis, specific DCs instruct specific inflammatory T cells.Item Open Access MicroRNA-29 is an essential regulator of brain maturation through regulation of CH methylation.(Cell reports, 2021-04) Swahari, Vijay; Nakamura, Ayumi; Hollville, Emilie; Stroud, Hume; Simon, Jeremy M; Ptacek, Travis S; Beck, Matthew V; Flowers, Cornelius; Guo, Jiami; Plestant, Charlotte; Liang, Jie; Kurtz, C Lisa; Kanke, Matt; Hammond, Scott M; He, You-Wen; Anton, ES; Sethupathy, Praveen; Moy, Sheryl S; Greenberg, Michael E; Deshmukh, MohanishAlthough embryonic brain development and neurodegeneration have received considerable attention, the events that govern postnatal brain maturation are less understood. Here, we identify the miR-29 family to be strikingly induced during the late stages of brain maturation. Brain maturation is associated with a transient, postnatal period of de novo non-CG (CH) DNA methylation mediated by DNMT3A. We examine whether an important function of miR-29 during brain maturation is to restrict the period of CH methylation via its targeting of Dnmt3a. Deletion of miR-29 in the brain, or knockin mutations preventing miR-29 to specifically target Dnmt3a, result in increased DNMT3A expression, higher CH methylation, and repression of genes associated with neuronal activity and neuropsychiatric disorders. These mouse models also develop neurological deficits and premature lethality. Our results identify an essential role for miR-29 in restricting CH methylation in the brain and illustrate the importance of CH methylation regulation for normal brain maturation.