Down-regulation of the non-neuronal acetylcholine synthesis and release machinery in acute allergic airway inflammation of rat and mouse

Life Sci. 2007 May 30;80(24-25):2263-9. doi: 10.1016/j.lfs.2007.01.026. Epub 2007 Jan 23.

Abstract

Acetylcholine (ACh), derived both from nerve fibres and from non-neuronal sources such as epithelial cells, is a major regulator of airway function. There is evidence that dysfunction of the neuronal cholinergic system is involved in the pathogenesis of asthma. Here, we asked whether the pulmonary non-neuronal ACh-synthesis and release machinery is altered in a rat and a mouse model of allergic airway disease. Animals were sensitized against ovalbumin, challenged by allergen inhalation, and sacrificed 24 or 48 h later. Targets of investigation were the high-affinity choline transporter-1 (CHT1), that mediates cellular uptake of choline, the ACh-synthesizing enzyme choline acetyltransferase (ChAT), the vesicular ACh transporter (VAChT), and the polyspecific organic cation transporters (OCT1-3), which are able to translocate choline and ACh across the plasma membrane. With cell-type specific distribution patterns, immunohistochemistry identified these proteins in airway epithelial cells and alveolar macrophages. Real-time RT-PCR revealed significant decreases in ChAT-, CHT1-, VAChT-, OCT-mRNA in the lung of sensitized and allergen challenged animals. These data were supported by immunohistochemistry, demonstrating reduced labeling intensity of airway epithelial cells. ChAT-, CHT1-, VAChT-, and OCT1-mRNA were also significantly reduced in cells recovered by bronchoalveolar lavage from sensitized and challenged rats. In conclusion, the pulmonary non-neuronal cholinergic system is down-regulated in acute allergic airway inflammation. In view of the role of ACh in maintenance of cell-cell-contacts, stimulation of fluid-secretion and of ciliary beat frequency, this down-regulation may contribute to epithelial shedding and ciliated cell dysfunction that occur in this pathological condition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / biosynthesis*
  • Acetylcholine / metabolism
  • Allergens / immunology
  • Animals
  • Blotting, Western
  • Cation Transport Proteins / genetics
  • Cation Transport Proteins / metabolism
  • Choline O-Acetyltransferase / genetics
  • Choline O-Acetyltransferase / metabolism
  • Down-Regulation
  • Epithelial Cells / metabolism
  • Female
  • Inflammation / genetics
  • Inflammation / immunology
  • Inflammation / metabolism*
  • Lung / immunology
  • Lung / metabolism*
  • Lung / pathology
  • Macrophages, Alveolar / metabolism
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Neurons / metabolism
  • Organic Cation Transporter 1 / genetics
  • Organic Cation Transporter 1 / metabolism
  • Ovalbumin / immunology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Inbred BN
  • Respiratory Hypersensitivity / genetics
  • Respiratory Hypersensitivity / immunology
  • Respiratory Hypersensitivity / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Vesicular Acetylcholine Transport Proteins / genetics
  • Vesicular Acetylcholine Transport Proteins / metabolism

Substances

  • Allergens
  • CHT1 protein, mouse
  • CHT1 protein, rat
  • Cation Transport Proteins
  • Membrane Transport Proteins
  • Organic Cation Transporter 1
  • RNA, Messenger
  • Vesicular Acetylcholine Transport Proteins
  • Ovalbumin
  • Choline O-Acetyltransferase
  • Acetylcholine