Fas-, Caspase 8-, and Caspase 3-dependent Signaling Regulates the Activity of the Aminophospholipid Translocase and Phosphatidylserine Externalization in Human Erythrocytes

Abstract

Apoptosis and erythrocyte senescence share the common feature of exposure of phosphatidylserine (PS) in the outer leaflet of the cells. Western analysis showed that mature red cells contain Fas, FasL, Fas-associated death domain (FADD), caspase 8, and caspase 3. Circulating, aged cells showed colocalization of Fas with the raft marker proteins G␣ s and CD59; the existence of Fas-associated FasL, FADD and caspase 8; and caspase 8 and caspase 3 activity. Aged red cells had significantly lower aminophospholipid translocase activity and higher levels of PS externalization in comparison with young cells. In support of our contention that caspases play a functional role in the mature red cell, the oxidatively stressed red cell recapitulated apoptotic events, including translocation of Fas into rafts, formation of a Fas-associated complex, and activation of caspases 8 and 3. These events were independent of calpain but dependent on reactive oxygen species (ROS) as evident from the effects of the ROS scavenger N-acetylcysteine. Caspase activation was associated with loss of aminophospholipid translocase activity and with PS externalization. ROS was not generated by treatment of cells with t-butyl hydroperoxide at 10°C, and Fas did not translocate into rafts. Concomitantly, neither formation of a Fas-associated signaling complex nor caspase activation could be observed, supporting the view that translocation of Fas into rafts was the trigger for the chain of events leading to caspase 3 activation. Our data demonstrate for the first time the novel involvement of Fas/caspase 8/caspase 3-dependent signaling in an enucleated cell leading to PS externalization, a central feature of erythrophagocytosis and erythrocyte biology.

The metabolites of glutamine prevent hydroxyl radical-induced apoptosis through inhibiting mitochondria and calcium ion involved pathways in fish erythrocytes

“…This suggested that • OH-induced PS exposure was caspase-dependent in carp erythrocytes. This is in accordance with the report that oxidative stress induces death receptors (Fas) with subsequent caspase-8 and caspase-3 activation that triggers loss of aminophospholipid translocase activity with subsequent PS externalization in human erythrocytes [92,93]. The caspases-involved PS exposure may be closely associated with intracellular ROS and cytochrome c in fish erythrocyte.…”

Dynamics of lipid raft components during lymphocyte apoptosis: The paradigmatic role of GD3

“…in erythrocytes, a sort of apoptosis has been described that implicates caspase activity [60] and CD95/Fas-mediated triggering. Strikingly, translocation of CD95/Fas into rafts could trigger caspase activation in these cells too [61]. A series of works on raft function has also been carried out by investigating the effects of filipin, MβCD or cholesterol synthesis blockers, such as mevastatin, as raft disruptors and analyzed the resulting alterations of the apoptotic machinery.…”

Loss of phospholipid asymmetry and elevated brain apoptotic protein levels in subjects with amnestic mild cognitive impairment and Alzheimer disease

“…These reactive alkenals have been found to interfere with PtdSer asymmetry via redox dependent flippase (Castegna et al, 2004;Daleke, 2003;Tyurina et al, 2004b). Furthermore, much evidence indicates that oxidative modification of flippase by reactive alkenals and/or apoptotic proteins, resulting in asymmetric collapse (Castegna et al, 2004;Kagan et al, 2002;Mandal et al, 2005;Mohmmad Abdul and Butterfield, 2005;Tyurina et al, 2004a), is greatly elevated in the early apoptotic phenotype of AD models (Herrmann and Devaux, 1990;Kagan et al, 2000).…”

“…Activated caspase-3 immunoreactivity has been detected in both neurons and astrocytes and found elevated in frontotemporal dementia (Su et al, 2000) and AD (Su et al, 2001). PtdSer exposure due to apoptosis has been found to occur downstream of caspase activation in some cell types (Mandal et al, 2002;Martin et al, 1996;Vanags et al, 1996); in non-neuronal cells like human erythrocytes, caspase activation is associated with loss of aminophospholipid translocase activity and subsequent PtdSer externalization (Mandal et al, 2005). Amnestic mild cognitive impairment (MCI) is considered a transition point between normal cognitive aging and dementia or probable AD (Petersen et al, 1999;Winblad et al, 2004).…”