Identifier: TDX:1614
Authors: Roig Bourgine, Bàrbara
Abstract:
Schizophrenia is one of the most common psychoses in the world today. It has a prevalence of 1% in the population and is of unknown etiology. One of the most widely accepted etiopathogenic hypotheses for schizophrenia is neurodevelopmental theory, which postulates that schizophrenia originates from a variety of neurogenetic and gliogenetic disorders during perinatal development. Many studies have reported that schizophrenic patients have alterations in their myelin (white matter of the brain). Axons must be myelinated if signals are to be properly transmitted between neurons. The cells that form the myelin sheaths of the axons in the CNS are the oligodendrocytes.In humans, the myelination process peaks in the perinatal, childhood and adolescence stages. It is during this last stage that the symptoms of schizophrenia become manifest. Several linkage studies indicate that the 6p chromosomal region may contain one or more susceptibility genes for schizophrenia. Our group chose a gene in this region, the gene encoding the discoidin domain receptor 1 (DDR1), as a candidate gene for schizophrenia.DDR1 is known to be a receptor tyrosine kinase which is highly expressed in proliferative areas during murine brain development, and has also been shown to be expressed in human brain. The DDR1 ligand is collagen, which promotes the proliferation and differentiation of the neurophitelial cells in rats. Our group has observed that DDR1 is significantly expressed in the white matter and particularly in oligodendrocytes during pre- and postnatal development in mice. Furthermore, the expression of this receptor follows a spatial-temporal pattern similar to the process of myelination.In this doctoral thesis we have made the first detailed study of the pattern of gene and protein expression of DDR1 in human brain, using specific techniques such as in situ hybridization, immunohistochemistry and quantification of RNAm. We found a positive association of DDR1 with schizophrenia in a case-control association study using markers of the SNP (single nucleotide polymorphism) type.We have also reported for the first time that DDR1 is a myelin protein in the human brain and that of the five different isoforms that are known only isoforms DDR1c and DDR1a are related to the myelin.The following scientific articles have been written as a result of this doctoral thesis:- Roig B, Virgos C, Franco N, Martorell L, Valero J, Costas J, Carracedo A, Labad A, Vilella E. The discoidin domain receptor 1 as a novel susceptibility gene for schizophrenia. Molecular Psychiatry. 2007. doi: 10.1038/sj.mp.4001995. IF: 11.8- Roig B, Franco-Pons N, Martorell L, Tomàs J, Costas J, Vogel WF, Vilella E. Identification of the tyrosine kinase receptor discoidin domain 1 (DDR1) as a novel myelin protein. Submitted to Glia. IF: 4.1- Roig B, Franco-Pons N, Martorell L, Vilella E. Quantitative analysis of DDR1 mRNA expression in normal and schizophrenic brain. Manuscript in preparation.