TITLE:
Cooperative apoptosis of coelomocytes of the holothurian Eupentacta fraudatrix and its modulation by dexamethasone
AUTHORS:
Olga A. Zaika, Lyudmila S. Dolmatova
KEYWORDS:
Phagocytes; Morula Cells; Cell Cooperation; Dexamethasone; Apoptosis; Cytokines
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.4 No.9,
September
3,
2013
ABSTRACT: The
capacities of phagocytes of subpopulation P1 (F) and morula cells (MC) of holothurian Eupentacta fraudatrix to modulate apoptosis of
each other as well as cytokine-dependent mechanisms and hormonal regulation of these cells’s interaction were studied.
The 18-h treatment of F with supernatants, obtained after centrifugation
of MC preincubated for 3 h with phosphate buffered saline (PSB) at the
temperature of 22℃(SMC3) resulted in a
significant growth of apoptosis level. A 30-min incubation of F with
supernatants of MC, preincubated for 24 h (SMC24), on the contrary, reduced the apoptosis level and increased the level of interleukine-1α (IL-1α)-like substances,
and 24-h incubation did not influence apoptosis and reduced level of
IL-1α-like substances. Thus, proapoptotic effects of MC’s supernatants in F inversely depended on time of their
preincubation with PSB and directly on time of incubation with F. Additionally,
this effect was opposite to variations in the level of IL-1α-like substances. The level of apoptosis declined after 30 min of
incubation but elevated after 24 h at the inverse treatment of MC with
supernatant, obtained after preincubation of F during 24 h (SF24). The level
of IL-1α-like substances dropped
after 30 min and insignificantly decreased after 24 h. Hence, SF24 proapoptotic
effect directly depended on time of incubation with MC and did not correspond
to variations in the level of IL-1α-like substances. 100 μM dexamethasone
stimulated apoptosis in F and MC in an inverse time-dependent manner during
24-h preincubation, and supernatants of cell suspensions obtained after such
preincubations, stimulated apoptosis and reduced the IL-1α-like substances level in target cells at both types of
interaction. IL-1α-like substances
aresupposed to be mediators for MC’s effects in F, but
not for F’s action on MC. In holothurians, steroid hormones apparently may
participate in the regulation of the immune response and cell cooperation.