RESUMO
The original version of this Article omitted the author Margarita Parada-kusz from the Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA.
RESUMO
Retinoic acid (RA), a dietary vitamin A metabolite, is crucial in maintaining intestinal homeostasis. RA acts on intestinal leukocytes to modulate their lineage commitment and function. Although the role of RA has been characterized in immune cells, whether intestinal epithelial cells (IECs) rely on RA signaling to exert their immune-regulatory function has not been examined. Here we demonstrate that lack of RA receptor α (RARα) signaling in IECs results in deregulated epithelial lineage specification, leading to increased numbers of goblet cells and Paneth cells. Mechanistically, lack of RARα resulted in increased KLF4+ goblet cell precursors in the distal bowel, whereas RA treatment inhibited klf4 expression and goblet cell differentiation in zebrafish. These changes in secretory cells are associated with increased Reg3g, reduced luminal bacterial detection, and an underdeveloped intestinal immune system, as evidenced by an almost complete absence of lymphoid follicles and gut resident mononuclear phagocytes. This underdeveloped intestinal immune system shows a decreased ability to clear infection with Citrobacter rodentium. Collectively, our findings indicate that epithelial cell-intrinsic RARα signaling is critical to the global development of the intestinal immune system.
Assuntos
Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Células Caliciformes/fisiologia , Mucosa Intestinal/fisiologia , Sistema Fagocitário Mononuclear , Receptor alfa de Ácido Retinoico/metabolismo , Tretinoína/metabolismo , Animais , Diferenciação Celular , Células Cultivadas , Homeostase , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Associadas a Pancreatite/genética , Proteínas Associadas a Pancreatite/metabolismo , Receptor alfa de Ácido Retinoico/genética , Transdução de Sinais , Peixe-ZebraRESUMO
Crohn's disease is a chronic disease characterized by oxidant-induced tissue injury and increased intestinal permeability. A consequence of oxidative damage is the accumulation of DNA strand breaks and activation of poly(ADP-ribose) polymerase (PARP), which subsequently catalyzes ADP-ribosylation of target proteins. In this study, we assessed the role of PARP in the colitis seen in interleukin (IL)-10 gene-deficient mice. IL-10 gene-deficient mice demonstrated significant alterations in colonic cellular energy status in conjunction with increased permeability, proinflammatory cytokine release, and nitrosative stress. After 14 days of treatment with the PARP inhibitor 3-aminobenzamide, IL-10 gene-deficient mice demonstrated normalized colonic permeability; reduced tumor necrosis factor-alpha and interferon-gamma secretion, inducible nitric oxide synthase expression, and nitrotyrosine levels; and significantly attenuated inflammation. Time course studies demonstrated that 3-aminobenzamide rapidly altered cellular metabolic activity and decreased cellular lactate levels. This was associated with normalization of colonic permeability and followed by a downregulation of proinflammatory cytokine release. Our data demonstrate that inhibition of PARP activity results in a marked improvement of colonic inflammatory disease and a normalization of cellular metabolic function and intestinal permeability.
