TY - JOUR
T1 - The role of caspase activation and mitochondrial depolarisation in cultured human apoptotic eosinophils
AU - Alenzi, Faris Q.
AU - Alenazi, Badi Q.
AU - AL-anazy, Fatma H.
AU - Mubaraki, Abdulla M.
AU - Salem, Mohamed L.
AU - Al-Jabri, Ali A.
AU - Lotfy, Mahmoud
AU - Bamaga, Mohammad S.
AU - AlRabia, Mohammed W.
AU - Wyse, Richard K.H.
N1 - Funding Information:
This work was supported by a grant from the King Abdulaziz City for Science and Technology (KACST) Ref No. (ARP-26-98).
PY - 2010/1
Y1 - 2010/1
N2 - Caspases are key intracellular molecules in the control of apoptosis, but little is known concerning their relative contribution to the cascade of events leading to eosinophil apoptosis. We examined caspase-3, -8, and -9 activities in receptor ligation dependent apoptosis induction in the cultured eosinophils (CE). CE cultured alone for 48 hours exhibited constitutive apoptosis (12% ± 1.2). Significant (P < 0.05) enhancement of eosinophil apoptosis was observed following monoclonal antibody (Mab) treatment with CD45 (40% ± 0.7), CD95 (36% ± 1.6), or CD69 (34% ± 0.2). Caspase activity was analysed using the novel CaspaTagTM technique and flow cytometry. CE ligated with CD45 (Bra55), CD95 (Fas) and CD69 Mab resulted in caspase-3 and -9 activation after 16 hours post-ligation. This trend in caspase-3 and -9 activation continued to increase significantly through to the 20 and 24 hours time points when compared to isotype control. Activated up-stream caspase-8 was detected 16 and 20 hours after treatment with CD45, CD95 and CD69 Mab followed by a trend toward basal levels at 24 hours. Ligation of CD95 was followed by mitochondrial permeabilization, as demonstrated by marked increase in mitochondrial transmembrane potential (Δ Ψm) at all time points. However, ligation with CD45 and CD69 failed to induce a change in Δ Ψm at 16 hours post-treatment compared to isotype control even though there was an alteration in mitochondrial downstream-caspase activity following ligation with these Mab(s) at this time point. At 20 and 24 hours post-ligation, CD45 or CD69 induce significantly altered levels of Δ Ψm. Thus, the intrinsic and extrinsic caspase pathways are involved in controlling receptor ligation-mediated apoptosis induction in human eosinophils, findings that may aid the development of a more targeted, anti inflammatory therapy for asthma.
AB - Caspases are key intracellular molecules in the control of apoptosis, but little is known concerning their relative contribution to the cascade of events leading to eosinophil apoptosis. We examined caspase-3, -8, and -9 activities in receptor ligation dependent apoptosis induction in the cultured eosinophils (CE). CE cultured alone for 48 hours exhibited constitutive apoptosis (12% ± 1.2). Significant (P < 0.05) enhancement of eosinophil apoptosis was observed following monoclonal antibody (Mab) treatment with CD45 (40% ± 0.7), CD95 (36% ± 1.6), or CD69 (34% ± 0.2). Caspase activity was analysed using the novel CaspaTagTM technique and flow cytometry. CE ligated with CD45 (Bra55), CD95 (Fas) and CD69 Mab resulted in caspase-3 and -9 activation after 16 hours post-ligation. This trend in caspase-3 and -9 activation continued to increase significantly through to the 20 and 24 hours time points when compared to isotype control. Activated up-stream caspase-8 was detected 16 and 20 hours after treatment with CD45, CD95 and CD69 Mab followed by a trend toward basal levels at 24 hours. Ligation of CD95 was followed by mitochondrial permeabilization, as demonstrated by marked increase in mitochondrial transmembrane potential (Δ Ψm) at all time points. However, ligation with CD45 and CD69 failed to induce a change in Δ Ψm at 16 hours post-treatment compared to isotype control even though there was an alteration in mitochondrial downstream-caspase activity following ligation with these Mab(s) at this time point. At 20 and 24 hours post-ligation, CD45 or CD69 induce significantly altered levels of Δ Ψm. Thus, the intrinsic and extrinsic caspase pathways are involved in controlling receptor ligation-mediated apoptosis induction in human eosinophils, findings that may aid the development of a more targeted, anti inflammatory therapy for asthma.
KW - Apoptosis
KW - Asthma
KW - Caspases
KW - Eosinophils
KW - Mitochondria
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U2 - 10.1016/j.sjbs.2009.12.005
DO - 10.1016/j.sjbs.2009.12.005
M3 - Article
C2 - 23961055
AN - SCOPUS:75149181266
SN - 1319-562X
VL - 17
SP - 29
EP - 36
JO - Saudi Journal of Biological Sciences
JF - Saudi Journal of Biological Sciences
IS - 1
ER -