1-alpha,25-Dihydroxyvitamin D3 regulates inducible nitric oxide synthase messenger RNA expression and nitric oxide release in macrophage-like RAW 264.7 cells.

Abstract

The expression of inducible nitric oxide synthase (iNOS) expression and release of nitric oxide (NO) from macrophages are markedly increased in granulomatous infections. Activation of macrophages 1alpha-hydroxylase results in an increase of 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)]. However, the significance of this increased production is not completely understood. In this study, we analyzed 1,25(OH)(2)D(3) and NO production in patients with tuberculosis infection and hypercalcemia and used lipopolysaccharide (LPS) to stimulate RAW 264.7 cells in an attempt to assess iNOS expression and gaseous NO production regulated by 1,25(OH)(2)D(3). Peroxynitrite (OONO(-)) production and lactate dehydrogenase activity were also examined. Without additional stimulation, peripheral-blood mononuclear cells (PBMCs) from patients with tuberculosis converted more 25-hydroxyvitamin D(3) to 1,25(OH)(2)D(3) than did those from normal controls. These PBMCs released less NO than did those from control subjects, at baseline and in the stimulated state. We found that 1,25(OH)(2)D(3) dose-dependently inhibited iNOS messenger RNA expression of the LPS-stimulated RAW 264.7 cells and also significantly reduced the gaseous NO release and OONO(-) production. Paralleling the 1,25(OH)(2)D(3)-induced inhibition of NO release were reductions in OONO(-) and LDH production. In conclusion, 1,25(OH)(2)D(3) inhibited iNOS expression and reduced NO production by LPS-stimulated macrophages in the range of physiological doses. Inhibition of the NO surge was coupled with a reduction in OONO(-) and LDH production. Increased 1,25(OH)(2)D(3) production and decreased release of NO from the PBMCs of patients with tuberculosis and hypercalcemia were also noted. We propose that 1,25(OH)(2)D(3) production by macrophages may protect themselves against oxidative injuries caused by the NO burst. In the case of tuberculosis infection, increased 1,25(OH)(2)D(3) synthesis may further contribute to the development of an unwanted phenomenon-hypercalcemia.

• Authors: Jer-Ming Chang, Mei-Chuan Kuo, Hung-Tien Kuo, Shang-Jyh Hwang, Jer-Chia Tsai, Hung-Chun Chen, Yung-Hsiung Lai
• Journal: The Journal of laboratory and clinical medicine (J Lab Clin Med) Vol. 143 Issue 1 Pg. 14-22 (Jan 2004) ISSN: 0022-2143 [Print] United States
• PMID: 14749681 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Lipopolysaccharides
• RNA, Messenger
• Peroxynitrous Acid
• Nitric Oxide
• L-Lactate Dehydrogenase
• NOS2 protein, human
• Nitric Oxide Synthase
• Nitric Oxide Synthase Type II
• Nos2 protein, mouse
• Calcitriol

Topics

• Animals
• Calcitriol (metabolism, pharmacology)
• Cell Line
• Dose-Response Relationship, Drug
• Humans
• L-Lactate Dehydrogenase (metabolism)
• Leukocytes, Mononuclear (drug effects, metabolism)
• Lipopolysaccharides (pharmacology)
• Macrophage Activation (drug effects)
• Macrophages (drug effects, metabolism)
• Male
• Mice
• Nitric Oxide (metabolism)
• Nitric Oxide Synthase (genetics)
• Nitric Oxide Synthase Type II
• Peroxynitrous Acid (metabolism)
• RNA, Messenger (metabolism)
• Reverse Transcriptase Polymerase Chain Reaction