title: Drosophila type IV collagen mutation associates with immune system activation and intestinal dysfunction.
abstract: The basal lamina (BM) contains numerous components with a predominance of type IV collagens. Clinical manifestations associated with mutations of the human COL4A1 gene include perinatal cerebral hemorrhage and porencephaly, hereditary angiopathy, nephropathy, aneurysms and muscle cramps (HANAC), ocular dysgenesis, myopathy, Walker–Warburg syndrome and systemic tissue degeneration. In Drosophila, the phenotype associated with dominant temperature sensitive mutations of col4a1 include severe myopathy resulting from massive degradation of striated muscle fibers, and in the gut, degeneration of circular visceral muscle cells and epithelial cells following detachment from the BM. In order to determine the consequences of altered BMfunctions due to aberrant COL4A1 protein, we have carried out a series of tests using Drosophila DTS-L3 mutants from our allelic series of col4a1 mutations with confirmed degeneration of various cell types and lowest survival rate among the col4a1 mutant lines at restrictive temperature. Results demonstrated epithelial cell degeneration in the gut, shortened gut, enlarged midgut with multiple diverticulae, intestinal dysfunction and shortened life span. Midgut immunohistochemistry analyses confirmed altered expression and distribution of BM components integrin PSI and PSII alpha subunits, laminin gamma 1, and COL4A1 both in larvae and adults. Global gene expression analysis revealed activation of the effector AMP genes of the primary innate immune system including Metchnikowin, Diptericin, Diptericin B, and edin that preceded morphological changes. Attacin::GFP midgut expression pattern further supported these changes. An increase in ROS production and changes in gut bacterial flora were also noted and may have further enhanced an immune response. The phenotypic features of Drosophila col4a1 mutants confirmed an essential role for type IV collagen in maintaining epithelial integrity, gut morphology and intestinal function and suggest that aberrant structure and function of the COL4A1 protein may also be a significant factor in modulating immunity.
authors.affiliation: Department of Genetics, University of Szeged, Középfasor 52, H-6726 Szeged, Hungary.
authors.forename: Márton
authors.initials: M
authors.lastname: Kiss
authors.affiliation: Department of Genetics, University of Szeged, Középfasor 52, H-6726 Szeged, Hungary.
authors.forename: András A
authors.initials: AA
authors.lastname: Kiss
authors.affiliation: Department of Genetics, University of Szeged, Középfasor 52, H-6726 Szeged, Hungary.
authors.forename: Monika
authors.initials: M
authors.lastname: Radics
authors.affiliation: Department of Genetics, University of Szeged, Középfasor 52, H-6726 Szeged, Hungary.
authors.forename: Nikoletta
authors.initials: N
authors.lastname: Popovics
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Szeged, Középfasor 52, H-6726 Szeged, Hungary.
authors.forename: Edit
authors.initials: E
authors.lastname: Hermesz
authors.affiliation: John A. Burns School of Medicine, University of Hawaii, 1960 East West Road, Honolulu, HI 96822, USA.
authors.forename: Katalin
authors.initials: K
authors.lastname: Csiszár
authors.affiliation: Department of Genetics, University of Szeged, Középfasor 52, H-6726 Szeged, Hungary. Electronic address: mink@bio.u-szeged.hu.
authors.forename: Mátyás
authors.initials: M
authors.lastname: Mink
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000378:metabolism; D024141:Collagen Type IV / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004195:Disease Models, Animal; D004330:Drosophila / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000069196:Gastrointestinal Microbiome; D005786:Gene Expression Regulation; D006801:Humans; D007113:Immunity, Innate; D007422:Intestines / Q000473:pathology / Q000503:physiopathology*; D009135:Muscular Diseases / Q000235:genetics* / Q000276:immunology* / Q000401:mortality / Q000503:physiopathology; D009154:Mutation
chemical_list: C000612155:COL4A1 protein, Drosophila; D024141:Collagen Type IV; D029721:Drosophila Proteins
keywords: Drosophila; Gut epithelia; Immunity; Type IV collagen