title: Loss of tumor necrosis factor alpha potentiates transforming growth factor beta-mediated pathogenic tissue response during wound healing.
abstract: Animal cornea is an avascular transparent tissue that is suitable for research on wound healing-related scarring and neovascularization. Here we show that loss of tumor necrosis factor alpha (TNFalpha) potentiates the undesirable, pathogenic response of wound healing in an alkali-burned cornea in mice. Excessive invasion of macrophages and subsequent formation of a vascularized scar tissue were much more marked in TNFalpha-null knockout (KO) mice than in wild-type mice. Such an unfavorable outcome in KO mice was abolished by Smad7 gene introduction, indicating the involvement of transforming growth factor beta or activin/Smad signaling. Bone marrow transplantation from wild-type mice normalized healing of the KO mice, suggesting the involvement of bone marrow-derived inflammatory cells in this phenomenon. Co-culture experiments showed that loss of TNFalpha in macrophages, but not in fibroblasts, augmented the fibroblast activation as determined by detection of alpha-smooth muscle actin, the hallmark of myofibroblast generation, mRNA expression of collagen Ialpha2 and connective tissue growth factor, and detection of collagen protein. TNFalpha in macrophages may be required to suppress undesirable excessive inflammation and scarring, both of which are promoted by transforming growth factor beta, and for restoration of tissue architecture in a healing alkali-burned cornea in mice.
authors.affiliation: Department of Ophthalmology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-0012, Japan. shizuya@wakayama-med.ac.jp.
authors.forename: Shizuya
authors.initials: S
authors.lastname: Saika
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ikeda
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamanaka
authors.forename: Kathleen C
authors.initials: KC
authors.lastname: Flanders
authors.forename: Yuka
authors.initials: Y
authors.lastname: Okada
authors.forename: Takeshi
authors.initials: T
authors.lastname: Miyamoto
authors.forename: Ai
authors.initials: A
authors.lastname: Kitano
authors.forename: Akira
authors.initials: A
authors.lastname: Ooshima
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakajima
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Ohnishi
authors.forename: Winston W-Y
authors.initials: WW
authors.lastname: Kao
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D003315:Cornea / Q000378:metabolism / Q000473:pathology*; D005347:Fibroblasts / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D051906:Smad7 Protein / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D014945:Wound Healing
chemical_list: D051906:Smad7 Protein; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha