Fibroblast growth factor 10 protects against particulate matter-induced lung injury by inhibiting oxidative stress-mediated pyroptosis via the PI3K/Akt/Nrf2 signaling pathway.

Particulate matter (PM) is a major environmental contaminant that causes and worsens respiratory diseases. Fibroblast growth factor 10 (FGF10), a paracrine fibroblast growth factor that specifically stimulates repair and regeneration after injury, has been shown to protect against PM-induced lung injury. However, the underlying mechanisms are still unclear. In this study, the protective effects of FGF10 were investigated using a PM-induced lung injury mouse model in vivo and BEAS-2B cells in vitro. According to the findings, FGF10 treatment alleviated PM-induced oxidative damage and pyroptosis in vivo and in vitro. Mechanistically, FGF10 activated antioxidative Nrf2 signaling. Inhibition of PI3K signaling with LY294002 or Nrf2 signaling with ML385 revealed that FGF10-mediated lung protection was mediated by the PI3K/Akt/Nrf2 pathway. These results collectively indicate that FGF10 inhibits oxidative stress-mediated pyroptosis via the PI3K/Akt/Nrf2 pathway, suggesting a possible therapy for PM-induced lung injury.

Fibroblast Growth Factor-10 (FGF-10) Mobilizes Lung-resident Mesenchymal Stem Cells and Protects Against Acute Lung Injury.

FGF-10 can prevent or reduce lung specific inflammation due to traumatic or infectious lung injury. However, the exact mechanisms are poorly characterized. Additionally, the effect of FGF-10 on lung-resident mesenchymal stem cells (LR-MSCs) has not been studied. To better characterize the effect of FGF-10 on LR-MSCs, FGF-10 was intratracheally delivered into the lungs of rats. Three days after instillation, bronchoalveolar lavage was performed and plastic-adherent cells were cultured, characterized and then delivered therapeutically to rats after LPS intratracheal instillation. Immunophenotyping analysis of FGF-10 mobilized and cultured cells revealed expression of the MSC markers CD29, CD73, CD90, and CD105, and the absence of the hematopoietic lineage markers CD34 and CD45. Multipotency of these cells was demonstrated by their capacity to differentiate into osteocytes, adipocytes, and chondrocytes. Delivery of LR-MSCs into the lungs after LPS injury reduced the inflammatory response as evidenced by decreased wet-to-dry ratio, reduced neutrophil and leukocyte recruitment and decreased inflammatory cytokines compared to control rats. Lastly, direct delivery of FGF-10 in the lungs of rats led to an increase of LR-MSCs in the treated lungs, suggesting that the protective effect of FGF-10 might be mediated, in part, by the mobilization of LR-MSCs in lungs.

Effect of FGF10 monoclonal antibody on psoriasis-like model in guinea pigs.

OBJECTIVE: To investigate the therapeutical effect of topical application of FGF10 monoclonal antibody on the guinea pig model with psoriasis. METHODS: Blank group, model group, hydrocortisone butyrate treatment group and high-dose (0.188 mg/ml), middle-dose (0.094 mg/ml) and low-dose (0.063 mg/ml) FGF10 antibody group were set, respectively. After two-week treatment, pathological changes of psoriasis-like models were observed by HE staining, and the difference in VEGF and PCNA expression levels among different groups was observed by immunohistochemical staining. RESULTS: All the test indicators of each treatment group were lower than those of the model group, and there was a significant difference (P<0.05). The inflammatory cell count of the high-dose FGF10 antibody group was not statistically different from those of the blank group (t=0.77, P=0.443), and the counts of the rest treatment groups were significantly higher than those of the blank group and the high-dose FGF10 antibody group (P<0.05). The epidermal thickness of each FGF10 antibody treatment group was significantly higher than that of hydrocortisone butyrate treatment group (P<0.05), while no statistical difference was found in the epidermal thickness among the FGF10 antibody treatment groups (P>0.05). FGF10 monoclonal antibodies can reduce the PCNA and VEGF expression in psoriasis-like model of guinea pig's ear. CONCLUSION: FGF10 monoclonal antibodies can affect keratinocyte proliferation and division and can also significantly inhibit the inflammatory response in the psoriasis model. Meanwhile, FGF10 monoclonal antibodies can produce a therapeutic effect on psoriatic lesions by inhibiting the abnormal epidermis cell proliferation and neovascularization of the dermis in the psoriasis model.

Topical application of a new monoclonal antibody against fibroblast growth factor 10 (FGF 10) mitigates propranolol-induced psoriasis-like lesions in guinea pigs.

OBJECTIVES: Psoriasis is a chronic inflammatory skin disease characterized by excessive proliferation of keratinocytes. Fibroblast growth factor 10 (FGF10) acts as a growth factor for keratinocyte proliferation. The aim of this study is to investigate whether FGF10 blockage, a new monoclonal antibody against FGF10 we generated, could mitigate topical propranolol-induced psoriasis-like lesions in guinea pigs. MATERIALS AND METHODS: The monoclonal anti-FGF10 was generated by a routine method and purified by affinity chromatography. The effect of FGF10 and anti-FGF10 on human keratinocyte HaCaT cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The back of the ears of individual guinea pigs was topically exposed to 5% propranolol emulsion to induce psoriasis-like lesions and randomly treated topically with phosphate buffered saline (PBS), hydrocortisone butyrate, or different doses of anti-FGF10. The pathologic changes and the degrees of inflammation in the auricular areas of individual animals were examined histologically. RESULTS: Characterization revealed that anti-FGF10 had a purity of 90% and a titer of 1:12800. We found that FGF10 stimulated HaCaT cell proliferation while treatment with different doses of anti-FGF10 inhibited FGF10-induced cell proliferation in a dose-dependent manner (100, 200 ng/ml, p < 0.05 vs. control; 400, 800, 1600 ng/ml, p < 0.01 vs. control). Compared to PBS-treated psoriatic animals, treatment with anti-FGF10, like hydrocortisone butyrate, greatly inhibited the severity of psoriasis-like lesions by reducing the Baker's scores, the thickness of epidermis, and the numbers of monocyte infiltrates in the dermis of animals. CONCLUSIONS: The newly generated anti-FGF10 monoclonal antibody inhibited the proliferation of human keratinocytes in vitro and mitigated inflammation and pathogenic changes in propranolol-induced psoriasis-like lesions in animals. Therefore, these findings may provide a proof of principle that blockage of FGF-10 may inhibit psoriasis-related inflammation.

Interactions between NF-κB and SP3 connect inflammatory signaling with reduced FGF-10 expression.

Inflammation inhibits normal lung morphogenesis in preterm infants. Soluble inflammatory mediators present in the lungs of patients developing bronchopulmonary dysplasia disrupt expression of multiple genes critical for development. However, the mechanisms linking innate immune signaling and developmental programs are not clear. NF-κB activation inhibits expression of the critical morphogen FGF-10. Here, we show that interactions between the RELA subunit of NF-κB and SP3 suppress SP1-mediated FGF-10 expression. SP3 co-expression reduced SP1-mediated Fgf-10 promoter activity, suggesting antagonistic interactions between SP1 and SP3. Chromatin immunoprecipitation of LPS-treated primary mouse fetal lung mesenchymal cells detected increased interactions between SP3, RELA, and the Fgf-10 promoter. Expression of a constitutively active IκB kinase ß mutant not only decreased Fgf-10 promoter activity but also increased RELA-SP3 nuclear interactions. Expression of a dominant-negative IκB, which blocks NF-κB nuclear translocation, prevented inhibition of FGF-10 by SP3. The inhibitory functions of SP3 required sequences located in the N-terminal region of the protein. These data suggested that inhibition of FGF-10 by inflammatory signaling involves the NF-κB-dependent interactions between RELA, SP3, and the Fgf-10 promoter. NF-κB activation may therefore lead to reduced gene expression by recruiting inhibitory factors to specific gene promoters following exposure to inflammatory stimuli.

Chemical modification of recombinant human keratinocyte growth factor 2 with polyethylene glycol improves biostability and reduces animal immunogenicity.

Recombinant human keratinocyte growth factor 2 (rhKGF-2) is a member of fibroblast growth factor protein family currently being investigated for its promising significant effects in treating epithelial damage. Molecular modification with polyethylene glycol (PEGylation) is an effective approach to improve protein biostability and decrease protein immunogenic activity. In this study, we modified rhKGF-2 through PEGylation at N-terminal residue using 20 kDa PEG-phenyl-isothiocyanate (PIT-PEG20K). PEGylated rhKGF-2 is then purified to near homogeneity by Sephadex G-25 gel filtration followed by a Heparin Sepharose TM CL-6B affinity chromatography. This PEGylated rhKGF-2 retained about 60% of mitogenic activity compared to the non-modified rhKGF-2. Its relative thermal stability at normal physiological temperature and structural stability were significantly enhanced. Moreover, the immunogenicity of PEGylated rhKGF-2 in mice is significant decreased compared to non-modified rhKGF-2. These results suggest that PEGylation of rhKGF-2 could be a more effective approach to the pharmacological and therapeutic application of rhKGF-2.