Anales RANF

P.60 MITOCHONDRIA ARE A KEY TARGET OF AMYLOID β - DEPENDENT DAMAGE IN MOUSE MICROGLIAL CELLS: ROLE OF THE P2X7 RECEPTOR AND PROTECTION BY NIMODIPINE. P. Chiozzi 1 , A.C. Sarti 1 , J.M. Sanz 2 , A.L. Giuliani 1 , E. Adinolfi 1 , V. Vultaggio-Poma 1 , M. Tonegato 1 ,A. Roman 1 , S. Falzoni 1 & F. Di Virgilio 1 . 1 University of Ferrara, Dept. of Morphology, Surgery and Experimental Medicine, Ferrara, Italy 2 University of Ferrara, Dept. of Medical Sciences, Ferrara, Italy The pathogenic mechanism responsible for Amyloid β -dependent (A β ) neurodegeneration is largely obscure despite several studies have evidenced a leading role of A β -stimulated TNF α , IL-1 β or reactive species accumulation in Alzheimer’s disease (AD) brains and the ensuing neuroinflammation. In a previous study we showed that the P2X7 receptor has a key role in A β -dependent microglial activation and injury. We also showed that nimodipine (a L-type calcium blocker permeable across the blood- brain-barrier) is a powerful inhibitor of pro-IL-1 β intracellular accumulation and pro- IL-1 β cleavage and mature IL-1 β release. Moreover in vivo nimodipine significantly reduced IL-1 β accumulation triggered by intra-hippocampal A β inoculation. In the present study we investigate more in depth the pro-inflammatory effect of soluble A β on mouse primary microglia cells ( from P2rx7-wt and P2rx7-deleted mouse), on N13 mouse microglia cell line and on N13 microglial cells selected for the low expression of the P2X7 receptor referred as N13R (ATP Resistant). Our data shows that A β is a powerful stimulus for activation of NF k B, Nalp3 inflammasome protein expression, Casp-1 activation and ROS production. These effects depend on P2X7 expression since they are strongly reduced in microglial cells derived from P2rx7-deleted mouse or N13R. We show that A β exerts toxic effects on mitochondria such as induction of hyperpolarization, cytochrome c release and ATP content reduction. Moreover, in isolated mitochondria, A β exerts an inhibitory effect on ATP-synthase activity. Nimodipine strongly reduced all A β -dependent phlogosis as well as toxic effect on mitochondria but has not protective outcome on isolated mitochondria. Our data underline the key role of P2X7 receptor as permissive factor A β toxicity in mouse microglia and demonstrate that nimodipine administration might be viable therapeutic strategy for AD.