Monocytes From Spontaneously Hypertensive Rats Show Increased Store-Operated and Second Messenger-Operated Calcium Influx Mediated by Transient Receptor Potential Canonical Type 3 Channels

• Published in: American journal of hypertension 2007-10, Vol.20 (10), p.1111-1118
• Main Authors: Liu, Dao Yan, Scholze, Alexandra, Kreutz, Reinhold, Wehland-von-Trebra, Markus, Zidek, Walter, Zhu, Zhi Ming, Tepel, Martin
• Format: Article
• Language: English
• Subjects: Animals; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; calcium; Calcium - metabolism; Cardiology. Vascular system; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Diglycerides - pharmacology; Down-Regulation - drug effects; Down-Regulation - physiology; Enzyme Inhibitors - pharmacology; Experimental diseases; hypertension; Hypertension - genetics; Hypertension - metabolism; Male; Medical sciences; Monocytes; Rats; Rats, Inbred SHR; Rats, Inbred WKY; RNA, Small Interfering - pharmacology; Second Messenger Systems - drug effects; Second Messenger Systems - physiology; Thapsigargin - pharmacology; Transient receptor potential canonical Type 3 channel; TRPC Cation Channels - genetics; TRPC Cation Channels - metabolism
• ISSN: 0895-7061; 1879-1905; 1941-7225
• DOI: 10.1016/j.amjhyper.2007.04.004

We recently showed that increased expression of the transient receptor potential canonical Type 3 (TRPC3) channel is associated with genetic hypertension. It is unknown whether store-operated TRPC3 channels, which are activated after depletion of intracellular stores, or second messenger-operated TRPC3 channels, which are activated by 1-oleoyl-2-acetyl-sn-glycerol, show augmented responses in monocytes in genetic hypertension and support the development of vascular disease. Using the fluorescent-dye technique, we studied store-depleted and thapsigargin-induced, store-operated calcium influx and 1-oleoyl-2-acetyl-sn-glycerol-induced second messenger-operated calcium influx into monocytes from spontaneously hypertensive rats (SHRs) and from normotensive Wistar-Kyoto rats (WKYs). The RNA interference for the downregulation of TRPC3 in monocytes by small, interfering RNA (siRNA) was performed and evaluated using in-cell Western assay. Thapsigargin-induced, store-operated calcium influx was significantly elevated in SHRs and was approximately double that observed in WKYs. In the presence of nimodipine, the thapsigargin-induced, store-operated calcium influx was also significantly higher in SHRs compared with WKYs. After stimulation of monocytes by angiotensin II, calcium influx was significantly elevated in SHRs, and was approximately double that observed in WKYs. The 1-oleoyl-2-acetyl-sn-glycerol-induced, second messenger-operated calcium influx was also significantly elevated in SHRs compared with WKYs. Thapsigargin-induced, store-operated calcium influx was reduced by the inhibitor 2-aminoethoxydiphenyl borane. After TRPC3 knockdown, the thapsigargin-induced, store-operated calcium influx, as well as 1-oleoyl-2-acetyl-sn-glycerol-induced calcium influx, was significantly more reduced in cells from SHRs compared with WKYs. The increased store-operated and second messenger-operated calcium influx through TRPC3 channels in monocytes from SHRs may be responsible for a more aggressive effect in promoting vascular disease in genetic hypertension.