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P a r t i c i p a n t s :<br />
Luciana Mosca, researcher; Italo Tempera, Alessandra<br />
Masci, post-doc fellows.<br />
C o l l a b o r a t i o n s :<br />
Dipartimento di Farmacologia, Sapienza-Università di Roma (Dr.<br />
Luciano Saso); Université Paris 6 Pierre et Marie Curie, Paris,<br />
France (Prof. Francesco Visioli); <strong>Istituto</strong> di Biologia e Patologia<br />
Molecolari, CNR, Roma (Dr. Gianni Colotti).<br />
Report of activity<br />
In neurodegenerative diseases such as Alzheimer’s<br />
and Parkinson’s disease, injury might be associated<br />
with altered function of misfolded proteins leading<br />
to the formation of aggregated proteins, the<br />
Amyloid beta and the α-synuclein, respectively.<br />
Amyloid beta peptide (Abeta), a 39-42 residue<br />
polypeptide derived from the proteolytic processing<br />
of the Amyloid precursor protein by secretases, is a<br />
major component of senile plaques and is considered<br />
to have a central role in the pathogenesis of<br />
Alzheimer’s disease.<br />
α-Synuclein can assume various conformations from<br />
monomeric to fibrillar, from unfolded in solution to<br />
alpha-helical in the presence of lipid-containing vesicles,<br />
to a beta-pleated sheet or amyloid structure in<br />
the fibrils that compose the Lewy bodies.<br />
It is well known that both Abeta and α -synuclein can<br />
rapidly undergo fibrillization giving rise to aggregated<br />
forms (Uversky, Curr Alzheimer Res. 2008,<br />
5:260) that is associated to the generation of oxygen<br />
free radicals (Smith et al., BBA 2007, 1768:1976).<br />
Oxidative stress is responsible of DNA damage<br />
which, in turn, is a prime activator of the enzyme<br />
poly(ADP-ribose)polymerase (PARP).<br />
PARP-1 is a zinc-binding nuclear enzyme which catalyzes<br />
the covalent addition of the ADP-ribose moiety<br />
of nicotinamide adenine dinucleotide (NAD + ) to<br />
proteins and the subsequent elongation step of the<br />
41<br />
Molecular genetics of eukaryotes - AREA 3<br />
Epigenetic modifications in neurodegenerative diseases<br />
Principal investigator: Maria d’Erme<br />
Professor of Biochemistry<br />
Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”<br />
Tel: (+39) 06 49910923; Fax: (+39) 06 4440062<br />
maria.derme@uniroma1.it<br />
polymer, which is involved in many physiological<br />
processes such as gene expression, maintenance of<br />
genomic stability and cell death. A causal relationship<br />
between PARP and neurodegeneration is<br />
demonstrated by the findings that parkinsonian neurotoxins<br />
and amyloid-beta potently activate PARP in<br />
dopaminergic neurons and hippocampus, respectively.<br />
In addition, poly(ADP-ribosylated) nuclear proteins<br />
were showed in the neurons of Alzheimer's<br />
patient autopsy brain (Love et al., Brain 1999,<br />
122:247). Further evidence of an involvement of<br />
PARP in neuronal death is based on the finding of<br />
Outerio et al. (BBRC 2007, 357:596) showing that<br />
PARP-1 inhibitors significantly counteract neurotoxicity<br />
in experimental models of neurodegenerative<br />
diseases.<br />
The aim of the present research is to elucidate the<br />
contribution of poly(ADP-ribosylation) process in<br />
neurodegeneration. To achieve this objective, the<br />
dopaminergic neuroblastoma cell line SH-SY5Y was<br />
treated: i) with Abeta 25-35 fragment (Abeta 25-35 ), in<br />
the presence or absence of a new PARP inhibitor, the<br />
4-chinazolinonic derivative MC2050. Abeta 25-35 is<br />
able to preserve all the properties of its full-length<br />
counterparts, in particular the neurotoxicity; ii) with<br />
5-S-cysteinyldopamine (CysDA), or 6-hydroxydopamine<br />
(OH-DA). CysDA has been recently indicated<br />
as a putative endogenous parkinsonian neurotoxin<br />
(Spencer et al., J Neurochem. 2002, 81:122;<br />
Mosca et al., J Neuroscience Res. 2008, 86:954) but its<br />
effects in vivo have not been deeply investigated so far.<br />
CysDA is not commercially available and is routinely<br />
synthesized in our laboratory by a slight modification<br />
of the procedure for 5-S-cysteinyldopa described by<br />
Chioccara and Novellino (Synthetic Commun. 1996,<br />
16:967). OH-DA is a well known parkinsonian neurotoxin<br />
and was used as a positive control.<br />
First objective<br />
We assessed the PARP activity both in vitro and in<br />
cells, in the presence or absence of Abeta25-35 frag-