Mechanisms of UV-induced human lymphocyte apoptosis.

The article reviews the results of the studies of marker parameters (indicators) of various pathways and mechanisms of apoptosis of lymphocytes in donor peripheral blood induced by UV light (240-390 nm) in doses of 151, 1510, and 3020 J/m. The article analyses the processes of DNA fragmentation, distortion of the structural asymmetry of the cell membranes, changes in the degree of DNA damage (single-strand breaks), transcriptional factor р53, cytochrome , Fas receptors (CD95), caspase-3, caspase-8, and caspase-9, reactive oxygen species, and calcium ions in UV modified cells. The study determined that programmed cell death of lymphocytes after UV irradiation with 1510 J/m involves the р53-dependent pathway of the nuclear mechanism, as well as receptor-mediated caspase mechanism, mitochondrial mechanism, and the mechanism associated with the defects in calcium homeostasis.

Modulation of Structural and Functional Properties of Human Lymphocytes by Reactive Oxygen Species.

The effects of ROS on functional properties (cytotoxic activity, antibody-producing activity, TNFα synthesis, and free cytosol calcium level), membrane structure (by expression of some surface markers), and apoptosis of lymphocytic cells were estimated in the peripheral blood of healthy volunteers. O, [Formula: see text], OH, and HO mostly suppressed cytotoxic activity of lymphocytes against Ehrlich ascites carcinoma cells and inhibited IgG synthesis and expression of receptors and surface markers (Fc receptors, CD3, CD19, and CD56). The exposure of lymphocytes to HO (10 M), O, and OH was followed by an increase in the level of a secondary messenger, intracellular calcium, in comparison with non-exposed cells.

[Structural and Functional Modifications of Human Lymphocytes in Dynamics of UV-Induced Development of Their Apoptosis].

The flow-cytometric analysis of condition of human peripheral blood lymphocytes in dynamics of development of the apoptosis induced by exposure to UV-light (240-390 nanometers) at a dose of 1510 J/m2 was carried out. Superficial architectonics and changes of the level of a membrane potential and functional activity of succinatedehydrogenase of mitochondrions are studied. The contribution of extracellular calcium to the processes of lymphocyte cellular death is revealed.

Second messengers cAMP, Ca2+, and NO modulate functional properties of human lymphocytes under conditions of exposure to UV light.

We studied the effect of UV light (240-390 nm) in doses of 75.5-4530 J/m(2) on functional properties and level of intracellular messengers (cAMP, Ca(2+), NO) in lymphocytic cells of the peripheral blood. Correcting effects of UV light in a dose of 151 J/m(2) on cytotoxic activity of lymphocytes against Ehrlich ascetic carcinoma and calcium concentration in lymphocyte cytosol were observed.

[Ways of realizing apoptosis of human lymphocytes induced by UV-light and reactive oxygen species].

Changes of DNA structural condition, the level of membrane Fas-receptor expression, caspase-3 functional activity, concentrations of Ca2+, p53 and cytochrome c proteins of human lymphocytes in dynamics of apoptosis development induced by UV-light (240-390 nm) at doses 151, 1510, 3020 J/m2 and reactive oxygen species (superoxide anion-radical, hydroxyl radicals, hydrogen peroxide, singlet oxygen) have been studied. UV-light and reactive oxygen species have been established to induce fragmentation of lymphocyte DNA after 20 h incubation of the modified cells. It has been shown, that the increase in the expression level of membrane death Fas-receptors is observed during 1-5 h after exposure oflymphocytes to UV-light and ROS compared with intact cells.