1. Expression of transient receptor potential C6 channels in human lung macrophages
- Author
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Parmjit Bahra, Christopher T. Poll, Louise E. Donnelly, Mariana Oana Popa, Onn Min Kon, Gabor Jarai, Andrew G. Nicholson, Su Li, John Westwick, Richard Russell, Tricia Finney-Hayward, Peter J. Barnes, and Martin Gosling
- Subjects
Pulmonary and Respiratory Medicine ,Adult ,Male ,Patch-Clamp Techniques ,Adipose tissue macrophages ,Clinical Biochemistry ,Macrophage-activating factor ,Blotting, Western ,TRPM Cation Channels ,TRPV Cation Channels ,Inflammation ,Biology ,Monocytes ,TRPC6 ,Transient receptor potential channel ,Pulmonary Disease, Chronic Obstructive ,TRPC3 ,Macrophages, Alveolar ,medicine ,TRPC6 Cation Channel ,Macrophage ,Humans ,Interleukin 8 ,RNA, Messenger ,Molecular Biology ,TRPC Cation Channels ,Microscopy, Confocal ,Reverse Transcriptase Polymerase Chain Reaction ,Cell Biology ,Middle Aged ,Flow Cytometry ,Cell biology ,Electrophysiology ,Case-Control Studies ,Immunology ,Female ,medicine.symptom - Abstract
Chronic obstructive pulmonary disease (COPD) is associated with pulmonary inflammation with increased numbers of macrophages located in the parenchyma. These macrophages have the capacity to mediate the underlying pathophysiology of COPD; therefore, a better understanding of their function in chronic inflammation associated with this disease is vital. Ion channels regulate many cellular functions; however, their role in macrophages is unclear. This study examined the expression and function of transient receptor potential (TRP) channels in human macrophages. Human alveolar macrophages and lung tissue macrophages expressed increased mRNA and protein for TRPC6 when compared with monocytes and monocyte-derived macrophages. Moreover, TRPC6 mRNA expression was significantly elevated in alveolar macrophages from patients with COPD compared with control subjects. There were no differences in mRNA for TRPC3 or TRPC7. Although mRNA for TRPM2 and TRPV1 was detected in these cells, protein expression could not be determined. Fractionation of lung-derived macrophages demonstrated that TRPC6 protein was more highly expressed by smaller macrophages compared with larger macrophages. Using whole-cell patch clamp electrophysiology, TRPC6-like currents were measured in both macrophage subpopulations with appropriate biophysical and basic pharmacological profiles. These currents were active under basal conditions in the small macrophages. These data suggest that TRPC6-like channels are functional on human lung macrophages, and may be associated with COPD.
- Published
- 2009