Abnormal Wnt and PI3Kinase signaling in the malformed intestine of lama5 deficient mice.
Laminins are major constituents of basement membranes and are essential for tissue homeostasis. Laminin-511 is highly expressed in the intestine and its absence causes severe malformation of the intestine and embryonic lethality. To understand the mechanistic role of laminin-511 in tissue homeostasis, we used RNA profiling of embryonic intestinal tissue of lama5 knockout mice and identified a lama5 specific gene expression signature. By combining cell culture experiments with mediated knockdown approaches, we provide a mechanistic link between laminin α5 gene deficiency and the physiological phenotype. We show that laminin α5 plays a crucial role in both epithelial and mesenchymal cell behavior by inhibiting Wnt and activating PI3K signaling. We conclude that conflicting signals are elicited in the absence of lama5, which alter cell adhesion, migration as well as epithelial and muscle differentiation. Conversely, adhesion to laminin-511 may serve as a potent regulator of known interconnected PI3K/Akt and Wnt signaling pathways. Thus deregulated adhesion to laminin-511 may be instrumental in diseases such as human pathologies of the gut where laminin-511 is abnormally expressed as it is shown here.
Inserm, U682, Strasbourg, France; Univ de Strasbourg, France.
Léa
L
Ritié
Caroline
C
Spenlé
Joël
J
Lacroute
Anne-Laure
AL
Bolcato-Bellemin
Olivier
O
Lefebvre
Christine
C
Bole-Feysot
Bernard
B
Jost
Annick
A
Klein
Christiane
C
Arnold
Michèle
M
Kedinger
Dominique
D
Bagnard
Gertraud
G
Orend
Patricia
P
Simon-Assmann
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D055786:Gene Knockout Techniques; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D007422:Intestines / Q000166:cytology* / Q000196:embryology; D007797:Laminin / Q000172:deficiency* / Q000235:genetics*; D051379:Mice; D032342:Muscle Cells / Q000166:cytology; D038081:Organogenesis / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics; D051153:Wnt Proteins / Q000378:metabolism*
D015415:Biomarkers; D007797:Laminin; D034741:RNA, Small Interfering; D051153:Wnt Proteins; C097043:laminin alpha5; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt