Extracellular branched-chain amino acids, especially valine, regulate maturation and function of monocyte-derived dendritic cells

Eiji Kakazu, Noriatsu Kanno, Yoshiyuki Ueno, Tooru Shimosegawa

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65 Citations (Scopus)

Abstract

The functions of dendritic cells (DCs) are impaired in patients with liver cirrhosis. It is well-known that cirrhotic patients show decreased levels of plasma branched-chain amino acids (BCAA). Although amino acids are associated with maintaining the cell structure and function in many organs, limited data are available regarding the role of amino acids including BCAA in the immune system. We aimed to investigate the roles of BCAA in the function of human monocyte-derived DCs (MoDC). CD14-positive monocytes (CD14 +) were isolated from PBMC from healthy volunteers and hepatitis C virus (HCV) cirrhotic patients. In medium deprived of BCAA or valine, monocytes were able to differentiate into immature, but not into mature, DCs and showed weak expression of CD83. The deprivation of leucine or isoleucine did not affect this process. The MoDC allostimulatory capacity was significantly decreased in medium deprived of BCAA or valine (p = 0.017, p = 0.012, Bonferroni's analysis, respectively). Annexin VFITC/propidium iodide staining showed that the DC yield and viability were not significantly different under any medium. Immunoblotting demonstrated that depletion of valine or leucine decreased phospho-S6 kinase expression. Valine increased dose-dependently the allostimulatory capacity and IL-12 production of MoDC from both healthy volunteers and HCV cirrhotic patients. An elevated extracellular concentration of valine could improve the DC function in cirrhotic patients. These data provide a rationale for nutrition therapy that could be beneficial to patients with cirrhosis.

Original languageEnglish
Pages (from-to)7137-7146
Number of pages10
JournalJournal of Immunology
Volume179
Issue number10
DOIs
Publication statusPublished - 2007 Nov 15

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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