CASP-9: A susceptibility locus for multiple sclerosis in Italy V. Andreoli a, ⁎, F. Trecroci a , A. La Russa a , P. Valentino b , F. Condino a , V. Latorre a , R. Nisticò b , D. Pirritano b , F. Del Giudice b , M. Canino b , R. Cittadella a , A. Quattrone a,b a Institute of Neurological Sciences, National Research Council, Pianolago di Mangone, Cosenza, Italy b Institute of Neurology, Campus di Germaneto, University “Magna Graecia”, Catanzaro, Italy abstract article info Article history: Received 10 December 2008 Received in revised form 24 February 2009 Accepted 5 March 2009 Keywords: Multiple sclerosis CASP-9 Polymorphism Association study Genetic susceptibility Caspase-9 is a primary effector CASP that executes programmed cell death, which plays an important role in the development of multiple sclerosis (MS). Polymorphisms in the CASP-9 gene may influence its activity, thereby modulating the susceptibility to MS. To test this hypothesis, we evaluated a SNP in the CASP-9 gene in a set of Italian patients from Southern Italy and healthy control subjects. Our results suggest that the presence of the G/G genotype represents a higher risk factor in our MS population and a differential production of CASP-9 might be a contributory factor in determining the severity of MS. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Multiple sclerosis (MS) is a chronic inflammatory and neurode- generative disease of undetermined aetiology, affecting mainly the white matter of the central nervous system (CNS) and is clinically characterised by progressive disability (Steinman, 1996). In recent years, several data have confirmed the presence of axonal damage in MS and have shown that the disability caused by the disease better correlates with axonal loss than it does with extensive demyelination (Trapp et al., 1998; Noseworthy et al., 2000). Although the initiating event is a matter of debate, epidemiological and genetic findings suggest that MS is an acquired autoimmune and inflammatory disease, triggered by unknown environmental factors in genetically susceptible individuals (Compston and Coles, 2002). These results demonstrate that individuals might be predisposed to MS as a result of the inheritance of many genetic factors of modest contribution that, if revealed, may present important targets for new therapies (Stewart, 1997; Oksenberg et al., 2001). What seems certain is that MS is a disease with heterogeneous pathogenic mechanisms, and several studies support the argument that MS is a primary disease of either axons, neurons or oligodendrocytes and that immune response is secondary to neurodegeneration (Trapp et al., 1998; Bö et al., 2003). Recently, neuronal apoptosis has been described in cortical MS lesions (Peterson et al., 2001) and in experimental autoimmune encephalo- myelitis (EAE), a rat model of MS (Meyer et al., 2001). The apoptotic programme is executed by a family of essential proteases known as caspases (Nicholson and Thornberry, 1997). So far, at least two main caspase-activating cascades have been characterised: the mitochon- dria-mediated caspase-3 activation by caspase-9 (intrinsic pathway) and death-receptor-induced caspase-3 activation by caspase-8 (extrinsic pathway) (Zheng and Flavell, 2000). Particularly, caspase- 9(CASP-9) plays a crucial role in the initiation phase of the intrinsic pathway for apoptosis. In fact, many proapoptotic stimuli engage the apoptotic machinery in the cells by causing the release of cytochrome- c from mitochondria, which then induces oligomerisation of a protein called Apoptotic protease activating factor-1 (Apaf-1) and recruitment of CASP-9 into a large complex known as the apoptosome. Apopto- some then activates the CASP-9 cascade downstream with effector caspases, leading to apoptosis (Srinivasula, 1998; Li et al., 1997). The mechanism is evolutionarily conserved and may play an important role in mediating neuronal death; dysregulation of this normal control mechanism then could be a contributor to various diseases char- acterised by excessive or inadequate cell death. These findings raise the intriguing possibility that genetic variations in the CASP-9 gene could influence susceptibility to the disease. CASP-9, mapped to the short arm of chromosome 1p36 (Hadano et al., 1999) in humans, is composed of nine exons; some polymorphisms have also been described within this gene. However, the potential role of the single nucleotide polymorphism (SNP) of the CASP-9 gene in establishing susceptibility to MS has never been clearly defined. In particular, a SNP in the coding region CASP-9 Ex5 + 32G N A causes a conservative change of a glutamine with an arginine (Q221R) (Hirano et al., 2001) and, thus, may have functional significance. In order to shed light on a Journal of Neuroimmunology 210 (2009) 100–103 ⁎ Corresponding author. Institute of Neurological Sciences, National Research Council, Pianolago di Mangone, 87050, Cosenza, Italy. Tel.: +39 09849801300; fax: +39 0984969306. E-mail address: v.andreoli@isn.cnr.it (V. Andreoli). 0165-5728/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.jneuroim.2009.03.013 Contents lists available at ScienceDirect Journal of Neuroimmunology journal homepage: www.elsevier.com/locate/jneuroim