Hiraku Suga1, Makoto Sugaya2, Hideki Fujita1, Yoshihide Asano1, Yayoi Tada1, Takafumi Kadono1, Shinichi Sato3. 1. Department of Dermatology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. 2. Department of Dermatology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. Electronic address: sugayam-der@h.u-tokyo.ac.jp. 3. Department of Dermatology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. Electronic address: satos-der@h.u-tokyo.ac.jp.
Abstract
BACKGROUND: Toll-like receptors (TLRs) have a crucial role in early host defense against invading pathogens. Recent studies suggest that TLRs play important roles in non-infections inflammation and tissue repair and regeneration. OBJECTIVE: To determine the roles of TLR2 and TLR4 in mouse wound healing using TLR2-deficient (TLR2(-/-)), TLR4-deficient (TLR4(-/-)), and TLR2/TLR4-deficient (TLR2/4(-/-)) mice. METHODS: Open wounds made in TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice were examined clinically and histologically. Cytokine expression in the wounded skin was also investigated. TGF-β production from macrophages stimulated by hyaluronan, a ligand for TLR2 and TLR4, was evaluated by real-time PCR. RESULTS: Wound areas in TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice were larger than wild-type mice both at days 3 and 7 after wounding, accompanied by decreased numbers of infiltrating macrophages in the dermis and decreased TGF-β and CCL5 mRNA expression in the wounded skin. Immunohistochemistry showed decreased numbers of macrophages expressing TGF-β and reduced CCL5 expression by keratinocytes in the wounded skin from TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice compared to wild-type mice. Moreover, TGF-β production from macrophages induced by hyaluronan stimulation in vitro was significantly decreased in the absence of TLRs, especially TLR4. Interestingly, macrophages and wounded skin from TLR2(-/-) mice showed decreased TLR4 mRNA expression compared to wild-type mice, suggesting that the effect of TLR2 deficiency was at least partially dependent on decrease in TLR4. Topical application of TGF-β and CCL5 significantly improved wound healing in TLR-deficient mice. CONCLUSION: TLR4, rather than TLR2, regulates wound healing through TGF-β and CCL5 expression.
BACKGROUND: Toll-like receptors (TLRs) have a crucial role in early host defense against invading pathogens. Recent studies suggest that TLRs play important roles in non-infections inflammation and tissue repair and regeneration. OBJECTIVE: To determine the roles of TLR2 and TLR4 in mouse wound healing using TLR2-deficient (TLR2(-/-)), TLR4-deficient (TLR4(-/-)), and TLR2/TLR4-deficient (TLR2/4(-/-)) mice. METHODS: Open wounds made in TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice were examined clinically and histologically. Cytokine expression in the wounded skin was also investigated. TGF-β production from macrophages stimulated by hyaluronan, a ligand for TLR2 and TLR4, was evaluated by real-time PCR. RESULTS: Wound areas in TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice were larger than wild-type mice both at days 3 and 7 after wounding, accompanied by decreased numbers of infiltrating macrophages in the dermis and decreased TGF-β and CCL5 mRNA expression in the wounded skin. Immunohistochemistry showed decreased numbers of macrophages expressing TGF-β and reduced CCL5 expression by keratinocytes in the wounded skin from TLR2(-/-), TLR4(-/-), and TLR2/4(-/-) mice compared to wild-type mice. Moreover, TGF-β production from macrophages induced by hyaluronan stimulation in vitro was significantly decreased in the absence of TLRs, especially TLR4. Interestingly, macrophages and wounded skin from TLR2(-/-) mice showed decreased TLR4 mRNA expression compared to wild-type mice, suggesting that the effect of TLR2 deficiency was at least partially dependent on decrease in TLR4. Topical application of TGF-β and CCL5 significantly improved wound healing in TLR-deficient mice. CONCLUSION:TLR4, rather than TLR2, regulates wound healing through TGF-β and CCL5 expression.
Authors: Frank M Davis; Aaron denDekker; Andrew Kimball; Amrita D Joshi; Mahmoud El Azzouny; Sonya J Wolf; Andrea T Obi; Jay Lipinski; Johann E Gudjonsson; Xianying Xing; Olesya Plazyo; Christopher Audu; William J Melvin; Kanakadurga Singer; Peter K Henke; Bethany B Moore; Charles Burant; Steven L Kunkel; Katherine A Gallagher Journal: J Immunol Date: 2020-03-23 Impact factor: 5.422
Authors: Frank M Davis; Andrew Kimball; Aaron denDekker; Amrita D Joshi; Anna E Boniakowski; Dylan Nysz; Ronald M Allen; Andrea Obi; Kanakadurga Singer; Peter K Henke; Bethany B Moore; Steven L Kunkel; Katherine A Gallagher Journal: J Immunol Date: 2019-02-01 Impact factor: 5.422