HS-stimulated bioenergetics in chicken erythrocytes and the underlying mechanism.

The production of HS and its effect on bioenergetics in mammalian cells may be evolutionarily preserved. Erythrocytes of birds, but not those of mammals, have a nucleus and mitochondria. In the present study, we report the endogenous production of HS in chicken erythrocytes, which was mainly catalyzed by 3-mercaptopyruvate sulfur transferase (MST). ATP content of erythrocytes was increased by MST-generated endogenous HS under normoxic, but not hypoxic, conditions. NaHS, a HS salt, increased ATP content under normoxic, but not hypoxic, conditions. ATP contents in the absence or presence of NaHS were eliminated by different inhibitors for mitochondrial electron transport chain in chicken erythrocytes. Succinate and glutamine, but not glucose, increased ATP content. NaHS treatment similarly increased ATP content in the presence of glucose, glutamine, or succinate, respectively. Furthermore, the expression and activity of sulfide:quinone oxidoreductase were enhanced by NaHS. The structural integrity of chicken erythrocytes was largely maintained during 2-wk NaHS treatment in vitro, whereas most of the erythrocytes without NaHS treatment were lysed. In conclusion, HS may regulate cellular bioenergetics as well as cell survival of chicken erythrocytes, in which the functionality of the electron transport chain is involved. HS may have different regulatory roles and mechanisms in bioenergetics of mammalian and bird cells.