The endogenous signaling molecule S-nitrosoglutathione (GSNO) and other S-nitrosylating agents can cause full maturation of the abnormal gene product ΔF508 cystic fibrosis (CF) transmembrane conductance regulator (CFTR). However, the molecular mechanism of action is not known. Here we show that Hsp70/Hsp90 organizing protein (Hop) is a critical target of GSNO, and its S-nitrosylation results in ΔF508 CFTR maturation and cell surface expression. S-nitrosylation by GSNO inhibited the association of Hop with CFTR in the endoplasmic reticulum. This effect was necessary and sufficient to mediate GSNO-induced cell-surface expression of ΔF508 CFTR. Hop knockdown using siRNA recapitulated the effect of GSNO on ΔF508 CFTR maturation and expression. Moreover, GSNO acted additively with decreased temperature, which promoted mutant CFTR maturation through a Hop-independent mechanism. We conclude that GSNO corrects ΔF508 CFTR trafficking by inhibiting Hop expression, and that combination therapiesusing differing mechanisms of action-may have additive benefits in treating CF.cystic fibrosis transmembrane conductance regulator | S-nitrosoglutathione corrector | treatment

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CD73 is a membrane-bound enzyme catalyzing the final step of the conversion of extracellular ATP to adenosine, which then binds to its receptors and signals via cAMP and non-cAMP-mediated pathways. While CD45RBlow helper T cells from wild-type and CD73 KO mice were both highly enriched in the FoxP3+ regulatory T cell transcription factor, cells from CD73 KO mice produced more IFN-γ and IL-17A and could not inhibit effector T cell proliferation and function in vitro. In vivo CD73 expression by both regulatory (CD45RBlow) and effector (CD45RBhigh) T cells was required for Treg to prevent effector T cell-induced colitis following adoptive transfer into immunodeficient Rag1 KO recipients. The cytokine profile in the intestine was skewed compared to the protective combination of wild-type CD45RBlow and wild-type CD45RBhigh. Donor CD45RBlow recovered from colitic mice had reduced FoxP3 and CD45RBhigh phenotype shifted from Th17 to Th1. If recipients lacked both Rag1 and CD73, wild-type CD45RBlow Th cells did not protect from T cell-induced colitis. CD45RBlow Th cells lost FoxP3, acquired Th1 and Th17 transcription factors, depleted recipient’s innate lymphoid cells and caused disease. Prior adoptive transfer of innate lymphoid cells protected these recipients from disease and maintained FoxP3 expression on cells of the CD45RBlow pool. Thus, CD73 on cells of both adaptive and innate immunity is required for effective regulatory T cell function in intestinal homeostasis.

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