Inhibition of TRPA1-like alleviated unfolded protein response and apoptosis by regulating cytoplasmic Ca2+ in Yesso scallop Patinopecten yessoensis under high temperature stress

Transient receptor potential ankyrin subtype 1 (TRPA1) is a nonselective cation channel protein typically forms ion channels that regulate intracellular calcium homeostasis, and can be induced by temperature and various chemicals. In the present study, the involvement of Py TRPA1-like in regulating unfolded protein response (UPR) and apoptosis in Yesso Scallop Patinopecten yessoen sis under high temperature stress was investigated. The mRNA transcripts of Py TRPA1-like were detected in haemocytes and all the examined tissues with the highest expression level in mantle. After TRPA1 activator (allyl-isothiocyanate, AITC) and high temperature (25°C) treatment, the expression level of Py TRPA1-like mRNA and the Ca 2+ content in haemocytes increased significantly ( p < 0.05) at 3 h, and then recovered to the normal level at 12 h, and the expression level of Py GRP78, Py IRE1, Py ATF6β, Py PERK and Py Caspase-3 mRNA in haemocytes, and Caspase-3 activity and apoptosis rate were also significantly upregulated ( p < 0.05). After TRPA1 antagonist (HC-030031) and high temperature (25°C) treatment, the intracellular Ca 2+ content, the transcripts of Py GRP78, Py IRE1 and Py Caspase-3 in haemocytes, as well as the Caspase-3 activity and apoptosis rate decreased significantly compared to the control group ( p < 0.05), while the Ca 2+ distribution in haemocytes showed no difference with that in control group. These results collectively suggest that Py TRPA1-like plays important roles in regulating UPR and apoptosis by mediating calcium influx under high temperature stress in scallop P. yessoensis .