S-nitrosothiol transport via PEPT2 mediates biological effects of nitric oxide gas exposure in macrophages.

Published

Journal Article

The pharmacological effects of nitric oxide (NO) administered as a gas are dependent on the conversion to S-nitrosocysteine, and as such are largely mediated by the L-type amino-acid transporters (LATs) in several cell types. The dipeptide transporter PEPT2 has been proposed as a second route for S-nitrosothiol (SNO) transport, but this has never been demonstrated. Because NO governs important immune functions in alveolar macrophages, we exposed rat alveolar macrophages (primary and NR8383 cells) to NO gas at the air-liquid interface ± LPS stimulation in the presence of PEPT2 substrate Cys-Gly (or the LAT substrate L-Cys) ± transporter competitors. We found that SNO uptake and NO-dependent actions, such as the activation of soluble guanylyl cyclase (sGC), the augmentation of sGC-dependent filamentous actin (F-actin) polymerization, phagocytosis, and the inhibition of NF-κB activation, were significantly augmented by the addition of Cys-Gly in a manner dependent on PEPT2 transport. We found parallel (and greater) effects that were dependent on LAT transport. The contribution of cystine/cysteine shuttling via system x cystine transporter (xCT) to SNO uptake was relatively minor. The observed effects were unaffected by NO synthase inhibition. The NO gas treatment of alveolar macrophages increased SNO uptake, the activation of sGC, F-actin polymerization, and phagocytosis, and inhibited NF-κB activation, in a manner dependent on SNO transport via PEPT2, as well as via LAT.

Full Text

Cited Authors

  • Brahmajothi, MV; Sun, NZ; Auten, RL

Published Date

  • February 2013

Published In

Volume / Issue

  • 48 / 2

Start / End Page

  • 230 - 239

PubMed ID

  • 23239496

Pubmed Central ID

  • 23239496

Electronic International Standard Serial Number (EISSN)

  • 1535-4989

International Standard Serial Number (ISSN)

  • 1044-1549

Digital Object Identifier (DOI)

  • 10.1165/rcmb.2012-0305oc

Language

  • eng