Ascorbate in aqueous humor augments nitric oxide production by macrophages.

ABSTRACT: Immunosuppressive molecules within the aqueous humor (AqH) are thought to preserve ocular immune privilege by inhibiting proinflammatory NO production by macrophages (MΦs). Consistent with previous observations, we observed that although MΦs stimulated in the presence of AqH expressed NO synthase 2 (NOS2) protein, nitrite concentrations in culture supernatants, an indirect measure of NO production, did not increase. Interestingly, NOS2 enzymatic activity, as measured by the conversion of L-arginine (L-Arg) into L-citrulline, was augmented in lysates of MΦs stimulated in the presence of AqH. These data suggested that intracellular L-Arg may have been limited by AqH. However, we observed increased mRNA expression of the L-Arg transporter, cationic amino acid transporter 2B, and increased L-A

SUBMITTER: McKenna KC 

PROVIDER: S-EPMC3538947 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature