Cytokine Profiling and Stat3 Phosphorylation in Epithelial–Mesenchymal Interactions between Keloid Keratinocytes and Fibroblasts

Abstract

We previously reported an increase in signal transducer and activator of transcription 3 (Stat3) activation in keloid fibroblasts, which contributes to collagen production, cell proliferation, and migration. We further investigated the effect of epithelial-mesenchymal interaction on Stat3 in normal and keloid fibroblasts in noncoculture and coculture conditions. pY705 Stat3 was higher in keloid fibroblasts compared to normal fibroblasts in noncoculture. However, a more drastic decrease in pY705 Stat3 was observed in keloid fibroblasts compared to normal fibroblasts when cocultured with their respective keratinocytes over 5 days. To explore this paracrine effect, we examined the secretion of cytokines by cytokine arrays. Altered cytokine production was detected in keloid fibroblasts and keratinocytes, either in noncoculture or coculture conditions. IL-6, IL-8, monocyte chemoattractant protein-1, tissue inhibitor of metalloproteinases (TIMPs)-1, and TIMP-2 were major cytokines detected. Angiogenin, oncostatin M (OSM), vascular endothelial cell growth factor, IGF-binding protein-1, osteoprotegerin, and transforming growth factor-beta2 were present in keloid keratinocyte-fibroblast coculture, but absent in normal keratinocyte-fibroblast coculture. Only IL-6 and OSM stimulated strong pY705 Stat3 and cell proliferation in both normal and keloid fibroblasts. Other cytokines increased proliferation of keloid fibroblasts, but not normal fibroblasts, suggesting an altered state in keloid fibroblasts. Multiple cytokines likely contribute to keloid pathogenesis and a combinatorial neutralizing antibody/cytokine therapy may be effective in ameliorating keloid scars.

Fluorofenidone protects against renal fibrosis by inhibiting STAT3 tyrosine phosphorylation

“…And it has been reported to mediate various cellular functions, including gene activation, cell differentiation, cell survival, and proliferation [18][19][20]. Notably, a number of growth factors and cytokines such as TGF-b1 [21], IFN-c [22], and IL-6 [23][24][25], oncostatin M (OSM) [26], high glucose (HG) [27], and Ang II [28] have been found to trigger this pathway, and then induce expression of multiple genes, including profibrotic [29] and pro-inflammatory genes [30]. Evidence derived from numerous clinical and animal models studies is emerging for the involvement of JAK/STAT cascade in renal disease.…”

Chemokines in Wound Healing and as Potential Therapeutic Targets for Reducing Cutaneous Scarring

“…154 Fibroblasts from keloid scars have been shown to have increased levels of CXCL8 compared with normal human fibroblasts. 10 This highlights a possible role for CXCL8 in leukocyte recruitment and activation in keloid scars.…”

“…Chemokines play a prominent role in normal wound healing, but altered expression is observed in keloid and hypertrophic scars as well as chronic wounds. [10][11][12] Consequently iatrogenic manipulation of specific chemokine signaling pathways could offer an alternative means to reduce wound fibrosis, chronic wound development, and the incidence of pathological scarring. 13 Complexities of chemokine physiology have delayed development of effective scar-reducing agents.…”

Comparative genomic hybridisation analysis of keloid tissue in Caucasians suggests possible involvement of HLA-DRB5 in disease pathogenesis

“…A strong immunogenetic component has previously been suggested in KD pathogenesis [7,19,35]. The presence of immune cells inWltrating the KD lesions have been previously described, and altered expression in several major cytokines involved in immune responses also suggest the involvement of immunity in KD pathogenesis [7,14,20]. In addition to the positive association with HLA-DRB1*15, KD has also been positively associated with HLA class I alleles (HLA-A*01, HLA-A*03, HLA-A*25, B*07, and HLA-Cw*0802), HLA-DQA1*0104, HLA-DQB1 alleles (HLA-DQB1*0501 and HLA-DQB1*0503) and 3 twolocus haplotypes (HLA-B*07-HLA-DQB1*0501, HLA-B*07-HLA-DRB1*15, HLA-DQB1*0503-HLA-DRB1*15) in Chinese Han individuals [21,22,24].…”