Morley P, Whitfield J F
Cell Signals Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario.
J Cell Physiol. 1993 Aug;156(2):219-25. doi: 10.1002/jcp.1041560202.
Dimethyl sulfoxide (DMSO) initiates a coordinated differentiation program in various cell types but the mechanism(s) by which DMSO does this is not understood. In this study, the effect of DMSO on intracellular calcium ion concentration ([Ca2+]i) was determined in primary cultures of chicken ovarian granulosa cells from the two largest preovulatory follicles of laying hens, and in three cell lines: undifferentiated P19 embryonal carcinoma cells, 3T3-L1 fibroblasts, and Friend murine erythroleukemia (MEL) cells. [Ca2+]i was measured in cells loaded with the Ca(2+)-specific fluoroprobe Fura-2. There was an immediate (i.e., within 5 sec), transient, two to sixfold increase in [Ca2+]i after exposing all cell types to 1% DMSO. DMSO was effective between 0.2 and 1%. The prompt DMSO-induced [Ca2+]i spike in all of the cell types was not prevented by incubating the cells in Ca(2+)-free medium containing 2 mM EGTA or by pretreating them with the Ca(2+)-channel blockers methoxyverapamil (D600; 100 microM), nifedipine (20 microM), or cobalt (5 mM). However, when granulosa cells, 3T3-L1 cells, or MEL cells were pretreated with lanthanum (La3+; 1 mM), which blocks both Ca2+ channels and membrane Ca2+ pumps, there was a sustained increase in [Ca2+]i in response to 1% DMSO. By contrast, pretreating P19 cells with La3+ (1 mM) did not prolong the DMSO-triggered [Ca2+]i transient. In all cases, the DMSO-induced [Ca2+]i surge was unaffected by pretreating the cells with the inhibitors of inositol phospholipid hydrolysis, neomycin (1.5 mM) or U-73, 122 (2.5 microM). These results suggest that DMSO almost instantaneously triggers the release of Ca2+ from intracellular stores through a common mechanism in cells in primary cultures and in cells of a variety of established lines, but this release is not mediated through phosphoinositide breakdown. This large, DMSO-induced Ca2+ spike may play a role in the induction of cell differentiation by DMSO.
二甲基亚砜（DMSO）可在多种细胞类型中启动协调的分化程序，但其作用机制尚不清楚。在本研究中，测定了DMSO对来自产蛋母鸡两个最大排卵前卵泡的鸡卵巢颗粒细胞原代培养物以及三种细胞系（未分化的P19胚胎癌细胞、3T3-L1成纤维细胞和弗氏小鼠红白血病（MEL）细胞）细胞内钙离子浓度（[Ca2+]i）的影响。使用Ca(2+)特异性荧光探针Fura-2加载细胞来测量[Ca2+]i。将所有细胞类型暴露于1% DMSO后，[Ca2+]i立即（即5秒内）出现短暂的两到六倍增加。DMSO在0.2%至1%之间有效。在含有2 mM EGTA的无钙培养基中孵育细胞，或用钙通道阻滞剂甲氧基维拉帕米（D600；100 microM）、硝苯地平（20 microM）或钴（5 mM）预处理细胞，均不能阻止所有细胞类型中DMSO诱导的[Ca2+]i快速升高。然而，当颗粒细胞、3T3-L1细胞或MEL细胞用镧（La3+；1 mM）预处理时，镧可阻断Ca2+通道和膜钙泵，此时对1% DMSO的反应中[Ca2+]i持续升高。相比之下，用La3+（1 mM）预处理P19细胞并不能延长DMSO触发的[Ca2+]i瞬变。在所有情况下，用肌醇磷脂水解抑制剂新霉素（1.5 mM）或U-73122（2.5 microM）预处理细胞，均不影响DMSO诱导的[Ca2+]i激增。这些结果表明，DMSO几乎能通过一种共同机制在原代培养细胞和各种已建立细胞系的细胞中瞬间触发细胞内储存钙的释放，但这种释放不是通过磷酸肌醇分解介导的。这种由DMSO诱导的大幅[Ca2+]i升高可能在DMSO诱导的细胞分化中起作用。
