Abstract
Transient receptor potential channel canonical 5 (TRPC5) is a non-selective ion channel; ion influx through TRPC5 causes activation of downstream signaling pathways. In addition, TRPC5 has been identified as having a potential role in pathological processes, particularly in diseases caused by cellular cation homeostasis dysregulation, such as bronchial asthma or pulmonary hypertension. However, the expression and distribution of TRPC5 in the human lung remain unclear. To date, TRPC5 has only been detected in a few cell types in the human lung, such as airway, pulmonary venous and arterial smooth muscle cells. The present study therefore aimed to investigate the protein expression of TRPC5 in the human lung and to evaluate its histological distribution. Human lung samples were obtained from six preserved body donors. After processing, both hematoxylin & eosin staining, as well as immunohistochemistry were performed. Microscopic analysis revealed medium to strong immunostaining signals in all lung structures examined, including the pleura, pulmonary arteries and veins, bronchioles, alveolar septa, type 1 and 2 pneumocytes, as well as alveolar macrophages. Current research suggests that TRPC5 may be involved in various pathological processes in the human lung and some pharmacological compounds have already been identified that affect the function of TRPC5. Therefore, TRPC5 may present a novel drug target for therapeutic intervention in various lung diseases. The results of the present study indicate that the TRPC5 protein is expressed in all examined histological structures of the human lung. These findings suggest that TRPC5 may be more important for physiological cell function and pathophysiological cell dysfunction in the lung than is currently known. Further research is needed to explore the role and therapeutic target potential of TRPC5 in the human lung.