Proline hydroxylase domain-containing enzymes regulate calcium levels in cardiomyocytes by TRPA1 ion channel

• Published in: Experimental cell research Vol. 407; no. 2; p. 112777
• Main Authors: Liu, Lan, Liu, Xingke, Liu, Mengchang, Xie, Defu, Yan, Hong
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.10.2021
• Subjects: 60 APPLIED LIFE SCIENCES; ANOXIA; Ca2; CALCIUM IONS; CALMODULIN; Cardiomyocytes; FLUORESCENCE; HOMEOSTASIS; HYDROXYLASES; INHIBITION; INOSITOL; METABOLISM; PHOSPHOTRANSFERASES; PROLINE; Proline hydroxylase domain-containing enzymes (PHD); RECEPTORS; RNA; SARCOPLASMIC RETICULUM; Transient receptor potential ankyrin 1(TRPA1); Transient receptor potential ankyrin 1(TRPA1); CaMKII; TRPA1; IP3R; HIF; Ca2; PKA; Cardiomyocytes; AMPK; Proline hydroxylase domain-containing enzymes (PHD); PHD; ODD
• ISSN: 0014-4827; 1090-2422
• DOI: 10.1016/j.yexcr.2021.112777

The proline hydroxylase domain-containing enzymes (PHDs) acts as cellular oxygen sensors, inducing a series of responses to hypoxia, especially during the regulation of metabolism and energy homeostasis. The increase of Ca2+ in cardiomyocytes, induced by the opening of PHD signaling pathway, is the key initiation signal necessary for the PHD-mediated regulation of the energy metabolism pathway, but the underlying molecular mechanism remains incompletely understood. This study used PHD inhibitors (PHIs) and PHD2-specific RNA interference (PHD2shRNA) to inhibit PHD signals in cardiomyocytes to explore whether transient receptor potential ankyrin 1 (TRPA1) is involved in the regulation of calcium ion influx in the PHD activation pathway associated with to AMP-activated protein kinase (AMPK). The Fluo-3AM probe was used to measure changes in free intracellular calcium ion concentrations, and Western blot analysis was used to detect the levels of phosphorylated (P)-AMPK, TRPA1, and P–Ca2+/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) levels. The PHI-mediated inhibition of PHD resulted in an increase in free Ca2+ fluorescence in cardiomyocytes, which activated AMPK, TRPA1, and CaMKⅡ. The TRPA1 inhibitor HC030031, the CaMKII inhibitor KN93, and a ryanodine inhibitor (Ryanodine) were all able to inhibit the PHI-induced increase in intracellular Ca2+ and AMPK activation. Both PHIs and PHD2shRNA were able to effectively activate CaMKII and TRPA1. However, an inositol 1,4,5-triphosphate receptor (IP3R) inhibitor and the protein kinase A (PKA) inhibitor H89 did not significantly inhibit the PHI-induced increase in intracellular Ca2+ and AMPK activation. These results indicated that PHD might activate the CaMKⅡ pathway through the TRPA1 ion channel, inducing the release of calcium from the sarcoplasmic reticulum through ryanodine receptor 2 (RyR2), activating AMPK to initiate the protective effects of hypoxia in cardiomyocytes. •PHD induces calcium release from cardiomyocytes through ryanodine channel.•PHD activates TRPA1 to induce extracellular calcium ions into the cell and further activate the ryanodine channel.•TRPA1 is involved in the regulation of PHD-Ca2+-AMPK signaling pathway.