Human lymphocytes transcribe the cystic fibrosis transmembrane conductance regulator gene and exhibit CF-defective cAMP-regulated chloride current

J Biol Chem. 1992 Feb 15;267(5):3242-8.

Abstract

Cystic fibrosis (CF) is the most common lethal genetic disease among Caucasians, primarily affecting epithelial tissues of the lung and gut. Mutations in a single gene, the cystic fibrosis transmembrane conductance regulator (CFTR), are responsible for this disease. Whether a physiological defect exists in the immune system of CF patients has remained controversial. A chloride ion transport defect has been described in human CF-derived lymphocytes; however, it has not been possible to detect CFTR mRNA in lymphocytes. We report here that normal human B-lymphoblasts display whole cell Cl- conductances induced by calcium-mediated pathways, volume regulation, and cAMP which are equivalent to currents described in epithelial cells. B-lymphoblasts from CF-affected humans demonstrated defective Cl- conductance regulation by cAMP but preserved regulation by calcium-mediated and volume regulation mechanisms. CFTR involvement in cAMP regulation of Cl- conductance in lymphocytes is further supported by our demonstration of the presence of appropriately spliced CFTR mRNA segments in human B and T lymphocytes as detected by an optimized reverse-transcription and polymerase chain reaction approach. The identity of the amplified products was confirmed by hybridization to CFTR-specific probes and DNA sequencing. Furthermore, the 3'-end of the gene was found in a T cell cDNA library. We conclude that CFTR mRNA is expressed in lymphocytes, consistent with the cAMP regulation of chloride transport present in normal lymphocytes but defective in CF-derived lymphocytes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Blotting, Southern
  • Cell Line
  • Chloride Channels
  • Chlorides / metabolism
  • Cyclic AMP / pharmacology
  • Cyclic AMP / physiology*
  • Cystic Fibrosis / genetics*
  • Cystic Fibrosis / physiopathology
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • DNA / genetics
  • DNA / isolation & purification
  • Electrophysiology
  • Gene Library
  • Humans
  • Ion Channels / physiology
  • Kinetics
  • Lymphocytes / physiology*
  • Membrane Proteins / genetics*
  • Membrane Proteins / physiology*
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides
  • Polymerase Chain Reaction / methods
  • RNA, Messenger / genetics
  • Transcription, Genetic*

Substances

  • CFTR protein, human
  • Chloride Channels
  • Chlorides
  • Ion Channels
  • Membrane Proteins
  • Oligodeoxyribonucleotides
  • RNA, Messenger
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • DNA
  • Cyclic AMP