Identification of Cardiac Expression Pattern of Transient Receptor Potential Vanilloid Type 1 (TRPV1) Receptor using a Transgenic Reporter Mouse Model. (15th October 2020)

• Record Type: Journal Article
• Authors: Hong, Juan; Lisco, Amanda M.; Rudebush, Tara L.; Yu, Li; Gao, Lie; Kitzerow, Oliver; Zucker, Irving H.; Wang, Han-Jun
• Is Part Of: Neuroscience letters. Volume 737(2020)
• Publication Date: 2020-10-15
• Subjects: TRPV1 Transient receptor potential vanilloid type 1 -- RTX reseniferitoxin -- CSAR cardiac sympathetic afferent reflex -- DRG dorsal root ganglia -- CHF chronic heart failure -- NF200 Neurofilament -- TnI Troponin I -- PGP9.5 protein gene product 9.5 -- GFP green fluorescent protein; tdTomato reporter -- Cardiac spinal afferents -- Dorsal root ganglia -- Autonomic nerve system -- Resiniferatoxin; Neurology -- Periodicals; Neurology -- Periodicals; Research -- Periodicals; Neurologie -- Périodiques; Neuroanatomie -- Périodiques; Neuropharmacologie -- Périodiques; Neurophysiologie -- Périodiques; Neurology; Periodicals; Electronic journals; 617.48
• DOI: 10.1016/j.neulet.2020.135320
• Languages: English
• ISSNs: 0304-3940

Abstract

Highlights: The TRPV1cre-tdTomato reporter mouse model was sensitive to detect the TRPV1 cells. The reporter mouse model suggested that TRPV1 channels were not expressed in cardiomyocytes. TRPV1 channels were expressed in cardiac blood vessels and cardiac nerve endings. This study has important implications for studying the TRPV1 channels in heart. Abstract: Transient receptor potential vanilloid type 1 (TRPV1) channels are structurally related, non-selective cation channels that exhibit a high permeability to calcium. Sensory nerve endings expressing TRPV1 channels play a prominent role in regulating the cardiac sympathetic afferent reflex and contribute to cardiac remodeling and dysfunction in chronic heart failure. However, the precise expression of TRPV1 channels in cardiomyocytes vs . non-cardiomyocytes remains debated. Here we utilized a tdTomato-GFP reporter mouse crossed with a mouse line expressing Cre recombinase under the control of the TRPV1 promoter to map the TRPV1 expression pattern in heart. In this model, TRPV1-negative cells express tdTomato protein (red), whereas TRPV1-positive cells express GFP protein (green). As we expected, substantial GFP expression was found in many small and medium diameter dorsal root ganglia neurons in heterozygous TRPV1-Cre +/-, tdTomato flox/flox +/- male mice, suggesting that this heterozygous model is sufficient for labeling TRPV1-positive cells. Furthermore, these results showed that GFP green staining was not detectable in cardiomyocytes. Instead, we found strong GFP green staining in cardiac blood vessels—thought to be arterioles—in the heart. We also observed strong GFP signals on PGP9.5-positive cardiac nerve endings in the epicardium. In summary, this study does not support the concept that TRPV1 channels are strongly expressed in mouse cardiomyocytes. We conclude that TRPV1 channels in mouse heart are mostly expressed on non-cardiomyocyte cells including cardiac nerve endings and vessels. These data have important implications for the modulations of cardiogenic reflexes.