Upregulation of neurokinin-1 receptor expression in the lungs of patients with sarcoidosis

J Clin Immunol. 2003 Sep;23(5):425-35. doi: 10.1023/a:1025381803192.

Abstract

Substance P (SP) is a proinflammatory neuropeptide that is secreted by sensory nerves and inflammatory cells. Increased levels of SP are found in sarcoid bronchoalveolar lavage fluid. SP acts by binding to the neurokinin-1 receptor and increases secretion of tumor necrosis factor-alpha in many cell types. We sought to determine neurokinin-1 receptor expression in patients with sarcoidosis compared with normal controls. Neurokinin-1 receptor messenger RNA and protein expression were below the limits of detection by reverse transcriptase-polymerase chain reaction and immunohistochemistry in peripheral blood mononuclear cells of healthy volunteers (n = 9) or patients with stage 1 or 2 pulmonary sarcoidosis (n = 10), but were detected in 1/9 bronchoalveolar lavage cells of controls compared with 8/10 patients with sarcoidosis (p = 0.012) and 2/9 biopsies of controls compared with 9/10 patients with sarcoidosis (p = 0.013). Immunohistochemistry localized upregulated neurokinin-1 receptor expression to bronchial and alveolar epithelial cells, macrophages, lymphocytes, and sarcoid granulomas. The patient in whom neurokinin-1 receptor was not detected was taking corticosteroids. Incubation of the type II alveolar and bronchial epithelial cell lines A549 and SK-LU 1 with dexamethasone downregulated neurokinin-1 receptor expression. Upregulated neurokinin-1 receptor expression in patients with sarcoidosis may potentiate substance P-induced proinflammatory cytokine production in patients with sarcoidosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cells, Cultured
  • Dexamethasone / pharmacology
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Female
  • Humans
  • Immunohistochemistry
  • Lung / drug effects
  • Lung / metabolism*
  • Lung / pathology*
  • Male
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, Neurokinin-1 / genetics*
  • Receptors, Neurokinin-1 / metabolism*
  • Sarcoidosis / genetics*
  • Sarcoidosis / metabolism*
  • Up-Regulation* / drug effects

Substances

  • RNA, Messenger
  • Receptors, Neurokinin-1
  • Dexamethasone