Dasatinib Attenuates Fibrosis in Keloids by Decreasing Senescent Cell Burden.

Keloids are skin tumours caused by aberrant growth of dermal fibroblasts. Cellular senescence contributes to aging and various pathological conditions, including cancer, atherosclerosis, and fibrotic diseases. However, the effects of cellular senescence and senolytic drugs on keloids remain largely unknown. This study investigated senescent fibroblasts in keloids and assessed the effects of dasatinib on these cells. Tissues acquired from keloid removal surgery were analysed for senescence-associated ß-galactosidase-positive cells, p16 expression, and the effects of dasatinib treatment on keloids. Keloid tissue was xenotransplanted into mice, and the effect of intralesional dasatinib injection on keloid growth was observed. The results showed that the numbers of ß-galactosidase-positive and p16-expressing cells were higher in the keloids compared with in the controls. Dasatinib induced selective clearance of senescent cells and decreased procollagen expression in cultured keloid fibroblasts. In this xenotransplant keloid mouse model, intralesional injection of dasatinib reduced gross keloid tissue weight and the expression of both procollagen and p16. In addition, dasatinib-treated keloid fibroblasts conditioned medium reduced procollagen and p16 expression in cultured keloid fibroblasts. In conclusion, these results suggest that an increased number of senescent fibroblasts may play an important role in the pathogenesis of keloids. Therefore, dasatinib could be an alternative treatment for patients with keloids.

Adiponectin-Based Peptide (ADP355) Inhibits Transforming Growth Factor-ß1-Induced Fibrosis in Keloids.

Keloids, benign cutaneous overgrowths of dermal fibroblasts, are caused by pathologic scarring of wounds during healing. Current surgical and therapeutic modalities are unsatisfactory. Although adiponectin has shown an antifibrotic effect, its large size and insolubility limit its potential use in keloid treatment. We investigated the effect of a smaller and more stable adiponectin-based peptide (ADP355) on transforming growth factor ß1 (TGF-ß1)-induced fibrosis in a primary culture of keloid fibroblasts prepared from clinically obtained keloid samples. Xenograft of keloid tissues on athymic nude mice was used to investigate the effect of intralesional injection of ADP355. ADP355 significantly attenuated the TGF-ß1-induced expression of procollagen type 1 in keloid fibroblasts (p < 0.05). Moreover, it inhibited the TGF-ß1-induced phosphorylation of SMAD3 and ERK, while amplifying the phosphorylation of AMP-activated protein kinase (p < 0.05). Knockdown of adiponectin receptor 1 reversed the attenuation of procollagen expression in ADP355-treated TGF-ß1-induced fibrosis (p < 0.05). ADP355 also significantly reduced the gross weight and procollagen expression of keloid tissues in xenograft mice compared to control animals. These results demonstrate the therapeutic potential of the adiponectin peptide ADP355 for keloids.

Topical treatment with a cathepsin G inhibitor, ß-keto-phosphonic acid, blocks ultraviolet irradiation-induced basement membrane damage in hairless mouse skin.

BACKGROUND: Ultraviolet light (UV) exposure contributes various effects to skin including damage of the basement membrane. Cathepsin G (CTSG) belongs to serine protease family, and its upregulation is involved in wrinkle formation by chronic UV irradiation. However, the effect of CTSG on the basement membrane damage in skin remains unclear. PURPOSE: To investigate the effects of topical treatment with a CTSG inhibitor, ß-keto-phosphonic acid (KPA), on basement membrane damage in chronically UV-irradiated hairless mouse skin. METHODS: The dorsal skin of hairless mice was exposed to UV three times per week for 8 weeks. KPA was applied immediately after each session of UV irradiation. The basement membrane components, CTSG expression, and neutrophil infiltration were analyzed by immunofluorescence staining. The basement membrane structures were visualized by transmission electron microscope. CTSG and MMP-13 protein levels were analyzed by Western blotting. Assessment of wrinkle formation was examined using a skin replica assay. RESULTS: ß-keto-phosphonic acid prevented UV irradiation-induced decrease in type VII collagen, laminin 332, and perlecan at the basement membrane zone and prevented UV-induced breakage of lamina densa and UV-induced shortening of hemidesmosome. KPA prevented UV-induced CTSG and MMP-13 expressions in chronically UV-irradiated hairless mice. Increase in neutrophil infiltration by UV irradiation and UV-induced wrinkle formation was also prevented by KPA. CONCLUSION: Our present study showed the possible involvement of CTSG in UV-induced basement membrane damage in skin through topical treatment with a CTSG inhibitor, KPA. Thus, inhibition of CTSG may be a useful strategy for the prevention of UV-induced basement membrane damage and photoaging.

Gasdermin C is induced by ultraviolet light and contributes to MMP-1 expression via activation of ERK and JNK pathways.

BACKGROUND: Ultraviolet (UV) radiation plays important roles in various skin diseases including premature aging and cancer. UV has been shown to regulate the expressions of many genes including matrix metalloproteinases (MMPs). Gasdermin C (GSDMC) belongs to Gasdermin family and is known to be expressed in the epithelial cells of many tissues including the skin. However, the functions of GSDMC remain poorly understood. OBJECTIVE: We aimed to investigate the role of GSDMC in UV-induced MMP-1, MMP-3, and MMP-9 expressions in human skin keratinocytes. METHODS: Primary human skin keratinocytes and an immortalized human skin keratinocyte cell line (HaCaT cells) were irradiated with UV. Knockdown and overexpression of GSDMC were performed to study the effect of GSDMC. The mRNA and protein levels were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, respectively. RESULTS: We found that GSDMC expression is increased by UV irradiation in human skin keratinocytes. Further studies showed that GSDMC expression is increased at relatively late time points after UV irradiation and that this GSDMC induction plays important roles in the expressions of MMP-1, but not of MMP-3 and MMP-9, and the activations of ERK and JNK induced by UV. In addition, we found that overexpression of GSDMC increases the MMP-1 expression and the activities of ERK and JNK and that GSDMC-induced MMP-1 expression is suppressed by inhibition of ERK or JNK activities. CONCLUSIONS: Our results suggest that GSDMC is increased by UV radiation and contributes to UV-induced MMP-1 expression through the activation of ERK and JNK pathways.

Ultraviolet light-induced gasdermin C expression is mediated via TRPV1/calcium/calcineurin/NFATc1 signaling.

Gasdermin (GSDM)­C is a member of the GSDM gene family and is expressed in the epithelial cells of various tissue types, including skin. GSDMC expression is induced by ultraviolet (UV) irradiation and contributes to UV­induced matrix metalloproteinase 1 expression in human skin keratinocytes. However, how UV irradiation induces GSDMC expression remains unclear. The present study aimed to investigate the role of transient receptor potential cation channel subfamily V member 1 (TRPV1) and a calcium/calcineurin­signaling pathway in UV­induced GSDMC expression in human skin keratinocytes. Suppression of TRPV1 activity by treatment with the TRPV1 antagonists capsazepine and ruthenium red significantly reduced UV­induced GSDMC expression, whereas direct activation of TRPV1 by capsaicin, a TRPV1 agonist, increased GSDMC expression. The results demonstrated that extracellular calcium and calcineurin activity may be necessary for UV­induced GSDMC expression in HaCaT cells. In addition, UV­induced GSDMC expression was either decreased or increased following knockdown or overexpression of nuclear factor of activated T­cells, cytoplasmic 1 (NFATc1), respectively. These data suggested that TRPV1 may serve an important role in the induction of GSDMC expression by UV and that UV­induced GSDMC expression may be mediated via a calcium/calcineurin/NFATc1 pathway.