Vitamin D Modulates Expression of the Airway Smooth Muscle Transcriptome in Fatal Asthma

PLoS One. 2015 Jul 24;10(7):e0134057. doi: 10.1371/journal.pone.0134057. eCollection 2015.

Abstract

Globally, asthma is a chronic inflammatory respiratory disease affecting over 300 million people. Some asthma patients remain poorly controlled by conventional therapies and experience more life-threatening exacerbations. Vitamin D, as an adjunct therapy, may improve disease control in severe asthma patients since vitamin D enhances glucocorticoid responsiveness and mitigates airway smooth muscle (ASM) hyperplasia. We sought to characterize differences in transcriptome responsiveness to vitamin D between fatal asthma- and non-asthma-derived ASM by using RNA-Seq to measure ASM transcript expression in five donors with fatal asthma and ten non-asthma-derived donors at baseline and with vitamin D treatment. Based on a Benjamini-Hochberg corrected p-value <0.05, 838 genes were differentially expressed in fatal asthma vs. non-asthma-derived ASM at baseline, and vitamin D treatment compared to baseline conditions induced differential expression of 711 and 867 genes in fatal asthma- and non-asthma-derived ASM, respectively. Functional gene categories that were highly represented in all groups included extracellular matrix, and responses to steroid hormone stimuli and wounding. Genes differentially expressed by vitamin D also included cytokine and chemokine activity categories. Follow-up qPCR and individual analyte ELISA experiments were conducted for four cytokines (i.e. CCL2, CCL13, CXCL12, IL8) to measure TNFα-induced changes by asthma status and vitamin D treatment. Vitamin D inhibited TNFα-induced IL8 protein secretion levels to a comparable degree in fatal asthma- and non-asthma-derived ASM even though IL8 had significantly higher baseline levels in fatal asthma-derived ASM. Our findings identify vitamin D-specific gene targets and provide transcriptomic data to explore differences in the ASM of fatal asthma- and non-asthma-derived donors.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Asthma / drug therapy
  • Asthma / genetics
  • Asthma / metabolism*
  • Chemokines / genetics
  • Chemokines / metabolism
  • Child
  • Cytokines / genetics
  • Cytokines / metabolism
  • Female
  • Gene Expression Regulation / drug effects
  • Humans
  • Male
  • Middle Aged
  • Muscle, Smooth / drug effects*
  • Muscle, Smooth / metabolism
  • Respiratory System / drug effects*
  • Respiratory System / metabolism
  • Transcriptome / drug effects*
  • Vitamin D / pharmacology*
  • Vitamin D / therapeutic use
  • Young Adult

Substances

  • Chemokines
  • Cytokines
  • Vitamin D

Associated data

  • GEO/GSE58434