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MECHANISMS RESPONSIBLE FOR BETA-AMYLOID-DEPENDENT REDUCTION OF ERYTHROCYTE DEFORMABILITY Francesco Misiti University of Cassino and Southern Lazio Cassino (Italy). Conflict of Interest. Francesco Misiti Has no real or apparent conflicts of interest to report. Erythrocytes and Alzheimer. - PowerPoint PPT Presentation
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MECHANISMS RESPONSIBLE FOR BETA-AMYLOID-DEPENDENT
REDUCTION OF ERYTHROCYTE DEFORMABILITY
Francesco MisitiUniversity of Cassino and Southern Lazio
Cassino (Italy)
Conflict of Interest
• Francesco Misiti
• Has no real or apparent conflicts of interest to report
o A are associated with cerebral blood vessels
o A are transferred to blood
o A are produced by platelets
o Blood cells are exposed to A(1-42) and (1-40)
o Erythrocytes interact with A(1-42)
o A alters erythrocyte shape and deformability
o A impairs oxygen delivery to brain
Erythrocytes and Alzheimer
ControlAmyloid
Effects of Aβ on erythrocyte morphology
Membrane AChE activity as a marker of membrane integrity
* P < 0.05 vs. control
Objective
o Nitric Oxide: a regulatory factor of erythrocyte mechanical properties
o Nitric Oxide synthase (eNOS) is expressed in erythrocyteso PKC andCaspase 3responsible for regulation on eNOS
function o Pentose Phosphate Pathway (PPP): responsible for
erythrocyte antioxidant defense
Clarify the role played by Nitric Oxide synthase (eNOS) signaling pathway in the A-dependent alteration of erythrocyte morphology
Western blot analysis showing the conformational species of A
Piacentini et al. J Neurochem (2008)
Western blot analysis showing the conformational species of A
Piacentini et al. J Neurochem (2008)
Control
Amyloid
Immuno-histochemical staining of erythrocyte activated nitric oxide synthase (eNOS)
* P< 0.05 vs. control;
Time course of the effects of Aβ on nitrite and nitrate levels in erythrocytes
suspensions
* P < 0.05 vs. control; # P < 0.05 vs. Aβ at 24 hours.
* P < 0.05 vs. control; # P < 0.05 vs. Aβ at 24 hours.
Time course of the effects of Aβ on nitrite and nitrate levels in erythrocytes
suspensions
AChE inhibitors abrogate the effects of Aβ on nitrite and nitrate levels in
erythrocytes suspensions
* P < 0.05 vs. control; # P < 0.05 vs. Aβ at 24 hours.
cytosol
membrane
Ctr A + PMA
(80 kDa) PKC
(80 kDa) PKC
+ PMA
amyloid
control
PKC activation by A
cytosol
membrane
Ctr A + PMA
(80 kDa) PKC
(80 kDa) PKC
+ PMA
amyloid
control
PKC activation by A
Clementi et al. Int J Biochem Cell Biol. 39: 727-735 (2007)
Caspase 3 activation by Aactivity
Ctr A
Misiti et al. Biochem Cell Biol.86: 1-8 (2008)
--32kDa
--20 kDa
Caspase 3 activation by AWB
Misiti et al. Biochem Cell Biol.86: 1-8 (2008) Mandal et al. JBC 278: 52551-52558 (2003)
Band 3 degradation by Caspase 3
Ctr A A
Ctr A
--32kDa
--20 kDa
Reduction in antioxidant defense (Pentose Phosphate Pathway)
Clementi et al. Int. J. Biochem Cell Biol., 36(10):2066-76 (2004)
Ctr A
** P < 0.05 vs. A at 24 hours
Misiti et al. Biochem Cell Biol.86: 1-8 (2008)
A dependent reduced stimulus for endogenous NO synthesis in the vasculature
Ctr A
Conclusions
A/erythrocyte interaction induces :
o an imbalance in the antioxidant defense (PPP flux reduction)
o Caspase 3 activationo PKCactivation o eNOS down-regulationo NO levels reduction
Conclusions
A/erythrocyte interaction induces :
o an imbalance in the antioxidant defense (PPP flux reduction)
o Caspase 3 activationo PKCactivation o eNOS down-regulationo NO levels reduction
Acknowledgements
University of Cassino and Southern Lazio- Cassino
Cristiana Carelli Alinovi
Catholic University-School of Medicine- Rome
Bruno Giardina
Research National Council (CNR)-ICRM & ISM
Beatrice SampaoleseMarco Girasole
:
UNIVERSITY OF CASSINO AND SOUTHERN LAZIO