Mj. Champagne et al., Protection against necrosis but not apoptosis by heat-stress proteins in vascular smooth muscle cells evidence for distinct modes of cell death, HYPERTENSIO, 33(3), 1999, pp. 906-913
Citations number
41
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
We have reported previously that cultured vascular smooth muscle cells (VSM
C) isolated from spontaneously hypertensive rats (SHR) show higher prolifer
ation and cell death than normotensive controls. In addition to protecting
cells against death, heat stress proteins (HSPs) appear to play a role in c
ell proliferation. This investigation examines the involvement of HSP72 and
HSP27 in altered SHR VSMC proliferation and death. We have performed detai
led discriminatory analysis to characterize which type of VSMC death is ind
uced by heat stress (HS) and serum deprivation, Serum deprivation induced a
poptosis (caspase-3 cleavage and DNA laddering) and secondary necrosis, the
2 processes being a continuum of each other. Ln contrast, acute HS (46 deg
rees C, 30 minutes), which inhibited BN.lx and SHR VSMC proliferation by 2-
fold, increased necrosis (by 5-fold and 2-fold, respectively) but not apopt
osis. HSP72 and HSP27 expression evoked in VSMC by mild HS (44 degrees C, 1
5 minutes) 6 hours before acute HS prevented the inhibition of proliferatio
n and induction of necrosis with no effect on serum deprivation-induced or
staurosporine-induced apoptosis. This induced expression of HSP72 and HSP27
did not eliminate the higher basal proliferation, apoptosis, and necrosis
of SHR VSMC compared with BN.lx VSMC, suggesting that these HSPs are not in
volved in altered SHR VSMC proliferation and death. Also, although apoptosi
s and necrosis may he a continuum, in VSMC the 2 processes may be distingui
shed by HS, in which only necrosis is prevented by prior HSP accumulation T
his observation may be of use in designing strategies for cellular protecti
on.