Overexpression of the dSPARC gene impairs wound healing in the Drosophila melanogaster model

F. PRADA; A. CHERNOMORETZ; C. ALVAREZ; A. LLERA; P. WAPPNER; E. MARTIN BLANCO; O. PODHAJCER

Chicago, Illinois, USA

Congreso; 50th Annual Drosophila Research Conference 50th Annual Drosophila Research Conference; 2009

  Wound healing is a natural process orchestrated by many different cell types and molecules.Nevertheless, the precise role of most of the components has been difficult to establish. As aresult of a global gene expression study to identify phylogenetically conserved genes involved inwound healing, the gene SPARC was shown to be a relevant participant in all of our consortiumstudied models, that included two mice strains, humanized skin, human organotypic cultures andDrosophila imaginal disc cultures. SPARC, an ECM component involved in cell-shape change,adhesion, proliferation, migration and differentiation, was seen down-regulated during thenormal healing process in all models. For this reason, we decided to engineer a transgenic fly tooverexpress SPARC in Drosophila (dSPARC) as an impaired healing model. dSPARC gain offunction in ectoderm and in the whole embryo affected dramatically the dorsal closure,producing a phenotype very similar to that observed with JNK mutants. Moreover, dSPARCoverexpression showed homophilic cell adhesion anomalies, diminishing levels of focal contactsand inhibition of cytoskeleton rearrangement all over the dorsal closure leading edge. Analysis ofthe full transcriptome of whole embryos overexpressing dSPARC resulted in a group of 26differentially expressed genes. Ontologic analysis showed the following biological functionsoverrepresented: membrane trafficking, PI3K pathway, cytoskeleton remodelling, lipidhomeostasis and immune response. We have validated the use of dSPARC gain of function as amodel of impaired healing and moreover, our data confirmed the importance of a geneimplicated in adhesion and cell shape changes in the physiology of dorsal closure movement.