Albanese J, Dainiak N
Department of Medicine, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada.
Stem Cells. 1997;15 Suppl 2:49-57. doi: 10.1002/stem.5530150709.
Whereas nonsolar ultraviolet C radiation primarily affects nuclei (i.e., where it is absorbed by nucleic acids) of eukaryotic cells, ultraviolet radiation of long (320-380 nm) wavelengths (ultraviolet A) and intermediate (290-320 nm) wavelengths (ultraviolet B) primarily affects lipid membranes. We have previously demonstrated that ultraviolet B irradiation alters the surface architecture of human B cells and impairs expression of an erythroid growth factor on their surface and on extracellular vesicles. Here, we examined the effects of ultraviolet B irradiation on the capacity of Chinese hamster ovary cells to undergo the process of exfoliation, and on the capacity of Chinese hamster ovary cells transfected with flt3/flk2 cDNA to express the cytokine flt3/flk2. Our results indicate that the rate of release of shed vesicles from untransfected Chinese hamster ovary cells is decreased after one to two h, at a time when there is electron microscopic evidence for retention of vesicles at the cell surface. These changes at the cell surface precede all other apparent morphological changes (including DNA condensation in the nucleus, swelling of the mitochondria and appearance of apoptotic bodies). Furthermore, plasma membranes and shed extracellular vesicles from ultraviolet B irradiated Chinese hamster ovary cells that have been transfected with flt3/flk2 cDNA fail to express the protein.
非太阳紫外线C辐射主要影响真核细胞的细胞核（即其被核酸吸收的部位），而长波长（320 - 380纳米）的紫外线（紫外线A）和中波长（290 - 320纳米）的紫外线（紫外线B）主要影响脂质膜。我们之前已经证明，紫外线B照射会改变人B细胞的表面结构，并损害其表面和细胞外囊泡上促红细胞生成因子的表达。在此，我们研究了紫外线B照射对中国仓鼠卵巢细胞脱落过程的能力，以及对转染了flt3/flk2 cDNA的中国仓鼠卵巢细胞表达细胞因子flt3/flk2的能力的影响。我们的结果表明，在一到两小时后，未转染的中国仓鼠卵巢细胞释放脱落囊泡的速率降低，此时有电子显微镜证据表明囊泡滞留在细胞表面。细胞表面的这些变化先于所有其他明显的形态学变化（包括细胞核中的DNA凝聚、线粒体肿胀和凋亡小体的出现）。此外，转染了flt3/flk2 cDNA的经紫外线B照射的中国仓鼠卵巢细胞的质膜和脱落的细胞外囊泡未能表达该蛋白质。
