{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,8]],"date-time":"2025-07-08T11:32:03Z","timestamp":1751974323827},"reference-count":0,"publisher":"American Physiological Society","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Cell Physiology"],"published-print":{"date-parts":[[1990,7,1]]},"abstract":"<jats:p> In the human monocytic line U-937, 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] increases cytosolic free calcium concentration ([Ca2+]i). 1,25-(OH)2D3 also enhances the synthesis of heat-shock proteins (HSPs) when U-937 cells are exposed to elevated temperatures. To establish whether these two effects of 1,25-(OH)2D3 are related, we examined the effects of calcium on the heat-shock (HS) response, as well as the influence of 1,25-(OH)2D3 on this system. The equilibrium dissociation constant (Kd) of the fluorescent probe used to measure [Ca2+]i, fura-2, at 37 and 45 degrees C was found to be 191 and 234 nM, respectively. Exposure of U-937 cells to 45 degrees C did not increase [Ca2+]i under conditions in which active efflux of the dye was prevented by the organic anion transport inhibitor probenecid (1 mM). In cells preincubated in calcium-free medium, with subsequent addition of 4 mM EGTA before HS, or exposed to the calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7), the increase in HSPs synthesis was not affected. Cell viability, assessed by [3H]thymidine uptake, was not different between cells exposed to HS in calcium-containing or calcium-free media. Moreover, the effects of 1,25-(OH)2D3 on the HS response were also observed in a calcium-depleted medium, indicating that the effects of 1,25-(OH)2D3 on HSP synthesis were not mediated by [Ca2+]i. <\/jats:p>","DOI":"10.1152\/ajpcell.1990.259.1.c77","type":"journal-article","created":{"date-parts":[[2017,12,24]],"date-time":"2017-12-24T15:57:30Z","timestamp":1514131050000},"page":"C77-C83","source":"Crossref","is-referenced-by-count":16,"title":["Calcium and the heat-shock response in the human monocytic line U-937"],"prefix":"10.1152","volume":"259","author":[{"given":"S.","family":"Kantengwa","sequence":"first","affiliation":[{"name":"Respiratory Division and Allergy Unit, Geneva University Hospital, Switzerland."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A. M.","family":"Capponi","sequence":"additional","affiliation":[{"name":"Respiratory Division and Allergy Unit, Geneva University Hospital, Switzerland."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J. V.","family":"Bonventre","sequence":"additional","affiliation":[{"name":"Respiratory Division and Allergy Unit, Geneva University Hospital, Switzerland."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"B. S.","family":"Polla","sequence":"additional","affiliation":[{"name":"Respiratory Division and Allergy Unit, Geneva University Hospital, Switzerland."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"24","container-title":["American Journal of Physiology-Cell Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.physiology.org\/doi\/pdf\/10.1152\/ajpcell.1990.259.1.C77","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T19:47:40Z","timestamp":1718653660000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.physiology.org\/doi\/10.1152\/ajpcell.1990.259.1.C77"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1990,7,1]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1990,7,1]]}},"alternative-id":["10.1152\/ajpcell.1990.259.1.C77"],"URL":"https:\/\/doi.org\/10.1152\/ajpcell.1990.259.1.c77","relation":{},"ISSN":["0363-6143","1522-1563"],"issn-type":[{"value":"0363-6143","type":"print"},{"value":"1522-1563","type":"electronic"}],"subject":[],"published":{"date-parts":[[1990,7,1]]}}}