Age and Vitamin D Receptor (VDR) Expression and Functionality in Peripheral Blood Mononuclear Cells (PBMC)

Abstract

ObjectiveCharacterize PBMC VDR expression and functionality by age and serum 25(OH) D.Methods40 adults ≥ 50 yrs provided pre‐influenza vaccination blood for PBMC isolation in fall 2009. Serum 25(OH) D was measured by liquid chromatography/mass spectrometry. Gene expression of VDR, 1α‐hydroxylase (1αOHase), cathelicidin, triggering receptor expressed on myeloid cells 1 (TREM1), retinoic acid‐inducible gene 1 (RIG1), and interferon β (IFNβ) was measured by quantitative reverse transcription polymerase chain reaction in unstimulated and lipopolysaccharide (LPS) or vitamin D‐treated PBMC.ResultsMean ± SD serum 25(OH) D was 30 ± 4 ng/mL and not associated with age. Unstimulated mRNA expression of VDR, 1αOHase, TREM1, and RIG1 did not differ by age. IFNβ mRNA expression was higher in subjects ≥ 80 vs. <70 yrs (p<0.05). LPS stimulation upregulated expression of VDR (p<0.01) and 1αOHase (p<0.05). 25(OH) D and 1, 25(OH)2 D added in vitro upregulated TREM1 and cathelicidin. Serum 25(OH) D was inversely associated with unstimulated (r = −0.31) and LPS‐stimulated (r = −0.41) TREM1 expression, and LPS‐stimulated VDR expression (r = −0.33), adjusting for age, self‐rated health, and functional status.ConclusionAge had no consistent association with expression or functionality of the VDR or 1αOHase genes. 25(OH) D levels were inversely associated with TREM1 and LPS‐stimulated VDR expression. This project has been funded by CDC grants 5 U18 IP000183–02 and 1 U18 IP000184–01.