title: Loss of integrin alpha9beta1 results in defects in proliferation, causing poor re-epithelialization during cutaneous wound healing.
abstract: The wound microenvironment comprises constituents, such as the extracellular matrix (ECM), that regulate with temporal and spatial precision, the migratory, proliferative, and contractility of wound cells. Prompt closure of the wound is an early and critical phase of healing and beta1 integrins are important in this process. We previously reported a marked increase in integrin alpha9beta1 expression in epidermal keratinocytes in cutaneous and corneal wounds. However, the functional role of keratinocyte alpha9beta1 during re-epithelialization is unknown and analysis has been precluded by the lethal phenotype of integrin alpha9beta1 knockout mice. We now report that in conditional integrin alpha9 knockout (K14-alpha9 null) mice, normal proliferation occurs in epidermal keratinocytes and corneal basal cells. Normal epidermal keratinocyte morphology is also retained. However, corneal basal cell morphology and epithelial thickness are altered, suggesting that loss of integrin alpha9beta1 results in abnormal corneal differentiation. In cutaneous wounds, the number of proliferating epidermal keratinocytes is significantly reduced in K14-alpha9 null mice compared with alpha9(fl/-) mice, but not in Cre (control) mice. The decreased keratinocyte proliferation observed in K14-alpha9 null mice negatively impacts healing, resulting in a thinner migrating epithelium, demonstrating that alpha9beta1 is crucial for efficient and proper re-epithelialization during cutaneous wound healing.
authors.affiliation: Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York 12208, USA.
authors.forename: Purva
authors.initials: P
authors.lastname: Singh
authors.forename: Chun
authors.initials: C
authors.lastname: Chen
authors.forename: Sonali
authors.initials: S
authors.lastname: Pal-Ghosh
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Stepp
authors.forename: Dean
authors.initials: D
authors.lastname: Sheppard
authors.forename: Livingston
authors.initials: L
authors.lastname: Van De Water
mesh_terms: D000483:Alleles; D000818:Animals; D049109:Cell Proliferation; D004848:Epithelium / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D016023:Integrins / Q000235:genetics* / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008954:Models, Biological; D008957:Models, Genetic; D012867:Skin / Q000378:metabolism*; D014945:Wound Healing
chemical_list: D005353:Fibronectins; D016023:Integrins; C113256:integrin alpha 9 beta 1