Role and Therapeutic Potential for Targeting Fibroblast Growth Factor 10/FGFR1 in Relapsed Rheumatoid Arthritis.

OBJECTIVE: Fibroblast-like synoviocytes (FLSs) contribute to inflammation and joint damage in rheumatoid arthritis (RA). However, the regulatory mechanisms of FLSs in relapse and remission of RA remain unknown. Identifying FLS heterogeneity and their underlying pathogenic roles may lead to discovering novel disease-modifying antirheumatic drugs. METHODS: Combining single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics, we sequenced six matched synovial tissue samples from three patients with relapse RA and three patients in remission. We analyzed the differences in the transcriptomes of the FLS subsets between the relapse and remitted phases. We validated several key signaling pathways using quantitative real-time PCR (qPCR) and multiplex immunohistochemistry (mIHC). We further targeted the critical signals in vitro and in vivo using the collagen-induced arthritis (CIA) model in rats. RESULTS: Lining and sublining FLS subsets were identified using scRNA-seq. Differential analyses indicated that the fibroblast growth factor (FGF) pathway was highly activated in the lining FLSs from patients with relapse RA for which mIHC confirmed the increased expression of FGF10. Although the type I interferon pathway was also activated in the lining FLSs, in vitro stimulation experiment suggested that it was independent of the FGF10 pathway. FGF10 knockdown by small interfering RNA in FLSs significantly reduced the expression of receptor activator of NF-κB ligand. Moreover, recombinant FGF10 protein enhanced bone erosion in the primary human-derived pannus cell culture, whereas the FGF receptor (FGFR) 1 inhibitor attenuated this process. Finally, administering an FGFR1 inhibitor displayed a therapeutic effect in a CIA rat model. CONCLUSION: The FGF pathway is a critical signaling pathway in relapse RA. Targeted tissue-specific inhibition of FGF10/FGFR1 may provide new opportunities to treat patients with relapse RA.

FGF10 attenuates allergic airway inflammation in asthma by inhibiting PI3K/AKT/NF-κB pathway.

BACKGROUND: The effect of fibroblast growth factor 10 (Fgf10) against allergic asthma has remained unclear, despite its importance in lung development and homeostasis maintenance. The purpose of this study was to investigate the protective effect and potential mechanism of Fgf10 on asthma. METHOD: House Dust Mite (HDM)-induced asthma mice were administered recombinant Fgf10 intranasally during activation. Flow cytometry and ELISA were performed to determine type of inflammatory cells and type 2 cytokines levels in bronchoalveolar lavage fluid (BALF). Hematoxylin and eosin (H&E) and periodic acid - Schiff (PAS) staining of lung sections were conducted to evaluate histopathological assessment. Transcriptome profiling was analyzed using RNA-seq, followed by bioinformatics and network analyses to investigate the potential mechanisms of Fgf10 in asthma. RT-qPCR was also used to search for and validate differentially expressed genes in human Peripheral Blood Mononuclear Cells (PBMCs). RESULTS: Exogenous administration of Fgf10 alleviated HDM-induced inflammation and mucus secretion in lung tissues of mice. Fgf10 also significantly inhibited the accumulation of eosinophils and type 2 cytokines (IL-4, IL-5, and IL-13) in BALF. The PI3K/AKT/NF-κB pathway may mediate the suppressive impact of Fgf10 on the asthma inflammation. Through RNA-seq analysis, the intersection of 71 differentially expressed genes (DEGs) was found between HDM challenge and Fgf10 treatment. GO and KEGG enrichment analyses indicated a strong correlation between the DEGs and different immune response. Immune infiltration analysis predicted the differential infiltration of five types of immune cells, such as NK cells, dendritic cells, monocytes and M1 macrophages. PPI analysis determined hub genes such as Irf7, Rsad2, Isg15 and Rtp4. Interestingly, above genes were consistently altered in human PBMCs in asthmatic patients. CONCLUSION: Asthma airway inflammation could be attenuated by Fgf10 in this study, suggesting that it could be a potential therapeutic target.

Clinical efficacy of blood derivatives on wound healing: A systematic review and network meta-analysis.

This study aims to evaluate the clinical effects of different blood derivatives on wound healing using network meta-analysis. PubMed, Embase, OVID, Web of Science, SCOPUS and Cochrane Central were searched to obtain studies about blood derivatives on wound healing until October 2023. R 4.2.0 and Stata 15.0 softwares were used for data analysis. Forty-four studies comprising 5164 patients were included. The results of network meta-analysis showed that the healing area from high to low was GF + ORCCB, ORCCB, GF, PRF, Unnas paste dressing, APG, PRP injection, PRP, PRP + thrombin gel, PPP, HPL, CT. The healing time from low to high was PRP + thrombin gel, GF, PRP, PC + K, PC, APG, PRF, CT, Silver sulfadiazine ointment. The number of patients cured from high to low was APG, PRP injection, PRP, Aurix, PRF, Leucopatch, HPL, Antimicrobial Ointment Dressing, CT, 60 µg/cm2 repifermin, 120 µg/cm2 repifermin, AFG, PPP. The order of analgesic effect from high to low was AFG, Aminogam gel, PRF, PRP, Oxidised oil, APG, GF, CT. The order of the number of wound infection cases from low to high is APG, 20 µg/cm2 repifermin, 60 µg/cm2 repifermin, PRP, LeucoPatch, CT, PPP, Antiseptic ointment dressing. Healing area: GF + ORCCB had the best effect; Healing time: PRP + thrombin gel took the shortest time. The number of cured patients and the reduction of wound infection: APG has the best effect. Analgesic effect: AFG has the best effect. More studies with large sample sizes are needed to confirm the above findings.

Distinct effects of Fgf7 and Fgf10 on the terminal differentiation of murine bladder urothelium revealed using an organoid culture system.

BACKGROUND: Dysregulation of the terminal differentiation of bladder urothelium is associated with the pathogenesis of urinary tract disorders. Fibroblast growth factor (Fgf)7 and Fgf10 stimulate urothelial proliferation; however, their roles in cellular differentiation remain unclear. In this study, we used an organoid system to investigate the roles of these Fgfs in regulating bladder urothelium differentiation and identify their distribution patterns in the mouse bladder. METHODS: Adult bladder epithelia (AdBE) isolated from adult mouse bladder tissues (AdBTs) were used to culture adult bladder organoids (AdBOs) in the presence of Fgf7 and Fgf10. The differentiation status of the cells in AdBTs, AdBEs, AdBOs, and neonatal bladder tissues (NeoBTs) was analyzed via quantitative real-time-PCR for the presence of undifferentiated cell markers (Krt5, Trp63, and Krt14) and differentiated cell markers (Krt20, Upk1a, Upk2, and Upk3a). Organoid cell proliferation was assessed by counting cell numbers using the trypan blue method. The effects of Fgf7 and Fgf10 on organoid differentiation were assessed using different doses of Fgfs, and the involvement of peroxisome proliferator-activated receptor γ (PPARγ) signaling in these processes was tested by introducing a PPARγ agonist (Rosiglitazone) and antagonist (T0070907) to the culture. The expression patterns of Fgf7 and Fgf10 were examined via in situ hybridization of AdBTs. RESULTS: AdBOs showed higher expression of undifferentiated cell markers and lower expression of differentiated cell markers than AdBTs, NeoBTs, and AdBEs, indicating the relatively immature state of AdBOs. Differentiation of AdBOs was enhanced by Rosiglitazone and Fgf7, suggesting an interplay of intracellular signals between Fgf7 and PPARγ. Co-addition of T0070907 suppressed Fgf7-mediated differentiation, demonstrating that PPARγ is activated downstream of Fgf7 to promote cellular differentiation into umbrella cells. Furthermore, we found that Fgf7 is predominantly expressed in the umbrella cells of the urothelium, whereas Fgf10 is predominantly expressed in the urothelium and stroma of AdBTs. CONCLUSIONS: We demonstrated that unlike Fgf10, Fgf7 induces cellular differentiation via PPARγ activity and has a unique tissue distribution pattern in the adult bladder. Further studies on the Fgf7-PPARγ signaling axis would provide insights into the differentiation mechanisms toward functional umbrella cells and the pathogenesis of several urinary tract diseases.

Fibroblast growth factor 10 alleviates acute lung injury by inhibiting excessive autophagy via Nrf2.

Acute lung injury (ALI) is associated with an increased incidence of respiratory diseases, which are devastating clinical disorders with high global mortality and morbidity. Evidence confirms that fibroblast growth factors (FGFs) play key roles in mediating ALI. Mice were treated with LPS (lipopolysaccharide: 5 mg/kg, intratracheally) to establish an in vivo ALI model. Human lung epithelial BEAS-2B cells cultured in a corresponding medium with LPS were used to mimic the ALI model in vitro. In this study, we characterized FGF10 pretreatment (5 mg/kg, intratracheally) which improved LPS-induced ALI, including histopathological changes, and reduced pulmonary edema. At the cellular level, FGF10 pretreatment (10 ng/mL) alleviated LPS-induced ALI accompanied by reduced reactive oxygen species (ROS) accumulation and inflammatory responses, such as IL-1ß, IL-6, and IL-10, as well as suppressed excessive autophagy. Additionally, immunoblotting and co-immunoprecipitation showed that FGF10 activated nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway via Nrf2 nuclear translocation by promoting the interaction between p62 and keap1, thereby preventing LPS-induced ALI. Nrf2 knockout significantly reversed these protective effects of FGF10. Together, FGF10 protects against LPS-induced ALI by restraining autophagy via p62-Kelch-like ECH-associated protein 1 (Keap1)-Nrf2 signaling pathway, implying that FGF10 could be a novel therapy for ALI.

Delivery of FGF10 by implantable porous gelatin microspheres for treatment of spinal cord injury.

Porous gelatin microspheres (GMSs) were constructed to enhance the neuroprotective effects of fibroblast growth factor 10 (FGF10) against spinal cord injury (SCI). The GMSs were prepared using a water­in­oil emulsion, followed by cross­linking, washing and drying. The blank GMSs had a mean particle size of 35 µm, with a coarse and porous surface. FGF10 was encapsulated within bulk GMSs via diffusion. To evaluate the effects of the FGF10­GMSs, locomotion tests were performed as a measure of the functional recovery of rats. Hematoxylin and eosin and Nissl staining were used to quantify tissue injury, and Evans blue staining was used to evaluate blood­spinal cord barrier restoration. Western blotting and TUNEL assays were employed to assess apoptotic activity. Immunohistochemical staining of neurofilament antibodies (NF200) was used to evaluate axonal rehabilitation. Compared with the groups intravenously administered FGF10 alone, disruption of the blood­spinal cord barrier and tissue injury were attenuated in the FGF10­GMS group; this group also showed less neuronal apoptosis, as well as enhanced neuronal and axonal rehabilitation. Implantable porous GMSs could serve as carriers for FGF10 in the treatment of SCI.

Fibroblast growth factor 10 delays the progression of osteoarthritis by attenuating synovial fibrosis via inhibition of IL-6/JAK2/STAT3 signaling in vivo and in vitro.

Synovial fibrosis is a driver in the progression of osteoarthritis (OA). Fibroblast growth factor 10 (FGF10) has prominent anti-fibrotic effects in many diseases. Thus, we explored the anti-fibrosis effects of FGF10 in OA synovial tissue. In vitro, fibroblast-like synoviocytes (FLSs) were isolated from OA synovial tissue and stimulated with TGF-ß to establish a cell model of fibrosis. After treatment with FGF10, we assessed the effects on FLS proliferation and migration using CCK-8, EdU, and scratch assays, and collagen production was observed using Sirius Red Stain. The JAK2/STAT3 pathway and expression of fibrotic markers were evaluated through western blotting (WB) and immunofluorescence (IF). In vivo, we treated mice with OA induced by surgical destabilization of the medial meniscus (DMM) with FGF10 and assessed the anti-OA effect using histological and immunohistochemical (IHC) staining of MMP13, and fibrosis was evaluated using HE and Masson's trichrome staining. The expression of IL-6/JAK2/STAT3 pathway components was determined using ELISA, WB, IHC, and IF. In vitro, FGF10 inhibited TGF-ß-induced FLS proliferation and migration, decreased collagen deposition, and improved synovial fibrosis. Moreover, FGF10 mitigated synovial fibrosis and improved the symptoms of OA in DMM-induced OA mice. Overall, FGF10 had promising anti-fibrotic effects on FLSs and improved OA symptoms in mice. The IL-6/STAT3/JAK2 pathway plays key roles in the anti-fibrosis effect of FGF10. This study is the first to demonstrate that FGF10 inhibited synovial fibrosis and attenuated the progression of OA by inhibiting the IL-6/JAK2/STAT3 pathway.

FGF10/FGFR2 Signaling: Therapeutically Targetable Vulnerability in Ligand-responsive Cholangiocarcinoma Cells.

BACKGROUND/AIM: Increasing evidence has revealed FGFR2 as an attractive therapeutic target for cancer including cholangiocarcinoma (CCA). The present study investigated the oncogenic mechanisms by which FGF10 ligand activates FGFR2 in CCA cells and determined whether FGFR inhibitors could suppress FGF10-mediated migration of CCA cells. MATERIALS AND METHODS: Effects of FGF10 on the proliferation, migration, and invasion of KKU-M213A cells were assessed using clonogenic and transwell assays. Protein expression levels of FGFR2 and pro-angiogenic factors were determined via immunoblotting and antibody array analysis. FGFR2 knockdown using a small interfering RNA was used to validate the role of FGF10 in promoting cell migration via FGFR2. The effects of infigratinib (FGFR inhibitor) on cell viability, were determined in KKU-100, KKU-M213A, KKU-452 cells. Moreover, the efficacy of the FGFR inhibitor in suppressing migration via FGF10/FGFR2 stimulation was assessed in KKU-M213A cells. RESULTS: FGF10 significantly increased the expression of phospho-FGFR/FGFR2 and promoted the proliferation, migration, and invasion of KKU-M213A cells. FGF10 increased the expression levels of p-Akt, p-mTOR, VEGF, Slug, and pro-angiogenic proteins related to metastasis. Cell migration mediated by FGF10 was markedly decreased in FGFR2-knockdown cells. Moreover, FGF10/FGFR2 promoted the migration of cells, which was suppressed by the FGFR inhibitor. CONCLUSION: FGF10/FGFR2 activates the Akt/mTOR and VEGF/Slug pathways, which are associated with the stimulation of migration and invasion in CCA. Moreover, the FGF10/FGFR2 signaling was inhibited by an FGFR inhibitor resulting suppression of cell migration, which warrants further studies on their clinical utility for CCA treatment.

Beneficial effects of fibroblast growth factor 10 supplementation during in vitro maturation of buffalo cumulus-oocyte complexes.

Fibroblast growth factor 10 (FGF10) is an important regulator of the mammalian cumulus-oocyte complex that plays a crucial role in oocyte maturation. In this study, we investigated the effects of FGF10 supplementation on the in vitro maturation (IVM) of buffalo oocytes and its related mechanisms. During IVM, the maturation medium was supplemented with a range of concentrations of FGF10 (0, 0.5, 5, and 50 ng/mL) and the resulting effects were corroborated using aceto-orcein staining, TUNEL apoptosis assay, detection of Cdc2/Cdk1 kinase in oocytes, and real-time quantitative PCR. In matured oocytes, the 5 ng/mL-FGF10 treatment resulted in a significantly increased nuclear maturation rate, which increased the activity of maturation-promoting factor (MPF) and enhanced buffalo oocyte maturation. Furthermore, it treatment significantly inhibited the apoptosis of cumulus cells, while simultaneously promoting its proliferation and expansion. This treatment also increased the absorption of glucose in cumulus cells. Thus, our results indicate that adding an appropriate concentration of FGF10 to a maturation medium during IVM can be beneficial to the maturation of buffalo oocytes and improve the potential of embryo development.

Role of FGF10/FGFR2b Signaling in Homeostasis and Regeneration of Adult Lacrimal Gland and Corneal Epithelium Proliferation.

Purpose: Fibroblast growth factor 10 (FGF10) is involved in eye, meibomian, and lacrimal gland (LG) development, but its function in adult eye structures remains unknown. This study aimed to characterize the role of FGF10 in homeostasis and regeneration of adult LG and corneal epithelium proliferation. Methods: Quantitative reverse transcription PCR was used for analysis of FGF10 expression in both early postnatal and adult mouse LG, and RNA sequencing was used to analyze gene expression during LG inflammation. FGF10 was injected into the LG of two mouse models of Sjögren's syndrome and healthy controls. Flow cytometry, BrdU cell proliferation assay, immunostaining, and hematoxylin and eosin staining were used to evaluate the effects of FGF10 injection on inflammation and cell proliferation in vivo. Mouse and human epithelial cell cultures were treated with FGF10 in vitro, and cell viability was assessed using WST-8 and adenosine triphosphate (ATP) quantification assays. Results: The level of Fgf10 mRNA expression was lower in adult LG compared to early postnatal LG and was downregulated in chronic inflammation. FGF10 injection into diseased LGs significantly increased cell proliferation and decreased the number of B cells. Mouse and human corneal epithelial cell cultures treated with FGF10 showed significantly higher cell viability and greater cell proliferation. Conclusions: FGF10 appears to promote regeneration in damaged adult LGs. These findings have therapeutic potential for developing new treatments for dry eye disease targeting the ability of the cornea and LG to regenerate.

FGF10 Therapeutic Administration Promotes Mobilization of Injury-Activated Alveolar Progenitors in a Mouse Fibrosis Model.

Idiopathic pulmonary fibrosis (IPF) is a devastating interstitial lung disease with dire consequences and in urgent need of improved therapies. Compelling evidence indicates that damage or dysfunction of AT2s is of central importance in the development of IPF. We recently identified a novel AT2 subpopulation characterized by low SFTPC expression but that is enriched for PD-L1 in mice. These cells represent quiescent, immature AT2 cells during normal homeostasis and expand upon pneumonectomy (PNX) and were consequently named injury-activated alveolar progenitors (IAAPs). FGF10 is shown to play critical roles in lung development, homeostasis, and injury repair demonstrated in genetically engineered mice. In an effort to bridge the gap between the promising properties of endogenous Fgf10 manipulation and therapeutic reality, we here investigated whether the administration of exogenous recombinant FGF10 protein (rFGF10) can provide preventive and/or therapeutic benefit in a mouse model of bleomycin-induced pulmonary fibrosis with a focus on its impact on IAAP dynamics. C57BL/6 mice and SftpcCreERT2/+; tdTomatoflox/+ mice aged 8-10 weeks old were used in this study. To induce the bleomycin (BLM) model, mice were intratracheally (i.t.) instilled with BLM (2 µg/g body weight). BLM injury was induced after a 7-day washout period following tamoxifen induction. A single i.t. injection of rFGF10 (0.05 µg/g body weight) was given on days 0, 7, 14, and 21 after BLM injury. Then, the effects of rFGF10 on BLM-induced fibrosis in lung tissues were assessed by H&E, IHC, Masson's trichrome staining, hydroxyproline and Western blot assays. Immunofluorescence staining and flow cytometry was used to assess the dynamic behavior of AT2 lineage-labeled SftpcPos (IAAPs and mature AT2) during the course of pulmonary fibrosis. We observed that, depending on the timing of administration, rFGF10 exhibited robust preventive or therapeutic efficacy toward BLM-induced fibrosis based on the evaluation of various pathological parameters. Flow cytometric analysis revealed a dynamic expansion of IAAPs for up to 4 weeks following BLM injury while the number of mature AT2s was drastically reduced. Significantly, rFGF10 administration increased both the peak ratio and the duration of IAAPs expansion relative to EpCAMPos cells. Altogether, our results suggest that the administration of rFGF10 exhibits therapeutic potential for IPF most likely by promoting IAAP proliferation and alveolar repair.

Evaluation of clinical and histological effects of KGF-2 and NGF on corneal wound healing in an experimental alkali burn rabbit model.

Endogenously produced peptide growth factors such as keratinocyte growth factor-2 (KGF-2) and nerve growth factor (NGF) play a key role in the natural corneal wound healing process. However, this self-healing ability of the corneal tissue is often impaired in cases of severe corneal damage, as in corneal alkali injuries. In the present study, we investigated the clinical and histopathological effects of topical recombinant human keratinocyte growth factor-2 and nerve growth factor treatments in a rabbit model of corneal alkali burn. After induction of an alkali burn, 24 rabbits were divided equally into three groups: control group, KGF-2 group, and NGF group. Clinical parameters including epithelial healing, opacification, neovascularization and central corneal thickness were evaluated on the first (D1), seventh (D7) and fourteenth (D14) days after injury. Corneal histology was performed using hematoxylin/eosin (H&E) and Masson's Trichrome stains. Immunohistochemical staining for matrix metalloproteinase-2 (MMP-2), MMP-9 and transforming growth factor-ß (TGF-ß) was performed. On D14, the percentage of epithelial defect and opacity were significantly less in the KGF-2 and NGF groups compared to the control group (p < 0.05). There was no significant difference between the groups in central corneal thickness. In the evaluation of neovascularization on D14, the NGF group was significantly less vascularized than the control group (p = 0.011). Histological examination showed a significant increase in stromal edema and inflammation in the control group compared to both treatment groups (p < 0.05). There was also a significant difference between the NGF and control groups in histological evaluation of epithelial repair and vascularization (p < 0.05). When immunoreactivity of MMP-2, MMP-9 and TGF-ß was examined, there was a significant increase in the control group compared to the NGF group (p < 0.05). Taken together, both NGF and KGF-2 treatments were effective for early re-epithelialization and decrease in inflammation, opacity and neovascularization after corneal alkali burn. The inhibitory effect of NGF treatment on chemical-induced neovascularization was found to be superior to KGF-2 treatment.

Retinoic acid and FGF10 promote the differentiation of pluripotent stem cells into salivary gland placodes.

BACKGROUND: Salivary glands produce saliva that play essential roles in digestion and oral health. Derivation of salivary gland organoids from pluripotent stem cells (PSCs) provides a powerful platform to model the organogenesis processes during development. A few studies attempted to differentiate PSCs into salivary gland organoids. However, none of them could recapitulate the morphogenesis of the embryonic salivary glands, and most of the protocols involved complicated manufacturing processes. METHODS: To generate PSC-derived salivary gland placodes, the mouse embryonic stem cells were first differentiated into oral ectoderm by treatment with BMP4 on day 3. Retinoic acid and bFGF were then applied to the cultures from day 4 to day 6, followed by a 4-day treatment of FGF10. The PSC-derived salivary gland placodes on day 10 were transplanted to kidney capsules to determine the regenerative potential. Quantitative reverse transcriptase-polymerase chain reaction, immunofluorescence, and RNA-sequencing were performed to identify the PSC-derived SG placodes. RESULTS: We showed that step-wise treatment of retinoic acid and FGF10 promoted the differentiation of PSCs into salivary gland placodes, which can recapitulate the early morphogenetic events of their fetal counterparts, including the thickening, invagination, and then formed initial buds. The PSC-derived salivary gland placodes also differentiated into developing duct structures and could develop to striated and excretory ducts when transplanted in vivo. CONCLUSIONS: The present study provided an easy and safe method to generate salivary gland placodes from PSCs, which offered possibilities for studying salivary gland development in vitro and developing new cell therapies.

Fibroblast growth factor 10 protects against UVB-induced skin injury by activating the ERK/YAP signalling pathway.

OBJECTIVES: Ultraviolet light B (UVB) irradiation can induce skin injury and result in keratinocytes proliferation inhibition. However, the molecular understanding of the repair during UVB-induced cell proliferation inhibition remains poorly understood. The purpose of this study was to explore the role and potential mechanism of FGF10 in promoting keratinocytes cell cycle and proliferation after UVB injury. MATERIALS AND METHODS: Expression of FGF10 protein was analysed in skin treated with UVB radiation by immunohistochemistry. The proliferation potential was examined by Immunofluorescence, Western Blot and RT-PCR under UVB radiation, treated with FGF10 protein or overexpression of FGF10 using adeno-associated virus. CCK8 kit was used to further detect cell proliferation ability. RESULTS: We found that FGF10 is highly expressed in skin treated with UVB. Overexpression of FGF10 has a protective effect against UVB-induced skin damage by balancing epidermal thickness and enhancing epidermal keratinocytes proliferation. Importantly, FGF10 is found to alleviate UVB-induced downregulation of YAP activity, then promoting keratinocytes proliferation. Disruption of YAP function, either with the small molecule YAP inhibitor Verteporfin (VP) or YAP small-interfering RNA (siRNA), largely abolishes the protective activity of FGF10 on epidermal keratinocytes proliferation. Meanwhile, disruption of ERK kinase (MEK) activity with U0126 or ERK siRNA hinder the positive influence of FGF10 on UVB-induced skin injury. CONCLUSION: FGF10 promotes epidermal keratinocytes proliferation during UVB-induced skin injury in an ERK/YAP-dependent manner.

Protection of Human Lens Epithelial Cells from Oxidative Stress Damage and Cell Apoptosis by KGF-2 through the Akt/Nrf2/HO-1 Pathway.

Oxidative stress exerts a significant influence on the pathogenesis of various cataracts by inducing degradation and aggregation of lens proteins and apoptosis of lens epithelial cells. Keratinocyte growth factor-2 (KGF-2) exerts a favorable cytoprotective effect against oxidative stress in vivo and in vitro. In this work, we investigated the molecular mechanisms of KGF-2 against hydrogen peroxide- (H2O2-) induced oxidative stress and apoptosis in human lens epithelial cells (HLECs) and rat lenses. KGF-2 pretreatment could reduce H2O2-induced cytotoxicity as well as reactive oxygen species (ROS) accumulation. KGF-2 also increases B-cell lymphoma-2 (Bcl-2), quinine oxidoreductase-1 (NQO-1), superoxide dismutase (SOD2), and catalase (CAT) levels while decreasing the expression level of Bcl2-associated X (Bax) and cleaved caspase-3 in H2O2-stimulated HLECs. LY294002, the phosphatidylinositol-3-kinase (PI3K)/Akt inhibitor, abolished KGF-2's effect to some extent, demonstrating that KGF-2 protected HLECs via the PI3K/Akt pathway. On the other hand, KGF-2 activated the Nrf2/HO-1 pathway by regulating the PI3K/Akt pathway. Silencing nuclear factor erythroid 2-related factor 2 (Nrf2) by targeted-siRNA and inhibiting heme oxygenase-1 (HO-1) through zinc protoporphyrin IX (ZnPP) significantly decreased cytoprotection of KGF-2. Furthermore, as revealed by lens organ culture assays, KGF-2 treatment decreased H2O2-induced lens opacity in a concentration-dependent manner. As demonstrated by these data, KGF-2 resisted H2O2-mediated apoptosis and oxidative stress in HLECs through Nrf2/HO-1 and PI3K/Akt pathways, suggesting a potential protective effect against the formation of cataracts.

FGF10 protects against particulate matter (PM)-induced lung injury via regulation of endoplasmic reticulum stress.

Exposure of the lungs to particulate matter (PM) leads to the development of respiratory disease and involves mechanisms such as oxydative stress, mitochondrial dysfunction and endoplasmic reticulum (ER) stress. However, there are no effective therapies to treat PM-induced lung diseases. Fibroblast growth factor 10 (FGF10) is a multifunctional growth factor mediating mesenchymal-to-epithelial signaling and displaying a significant therapeutic potential following injury. The present research aims to investigate the regulatory mechanism of FGF10 on ER stress in PM-induced lung injury. PM-induced lung injury leads to peribronchial wall thickening and marked infiltration of inflammatory cells which is associated with increased secretion of inflammatory cytokines. The results show that FGF10 treatment attenuates PM-induced lung injury in vivo and reversed ER stress protein GRP78 and CHOP levels. Moreover, comparison of human bronchial epithelial cells cultured with PM and FGF10 vs PM alone shows sustained cell proliferation and restrained secretion of inflammatory cytokines supporting FGF10's protective role. Significantly, both ERK1/2 and PI3K/AKT inhibitors largely abolished the impact of FGF10 on PM-induced ER stress. Taken together, both in vivo and in vitro experiments showed that FGF10, via the activation of ERK1/2 and PI3K/AKT signaling, protects against PM-induced lung injury through the regulation of ER stress. Therefore, FGF10 represents a potential therapy for PM-induced lung injury.

Controlled release of KGF-2 for regulation of wound healing by KGF-2 complexed with "lotus seedpod surface-like" porous microspheres.

Keratinocyte growth factor-2 (KGF-2) can regulate the proliferation and differentiation of keratinocyte, which plays a remarkable role in maintaining normal tissue structure and promoting wound healing. As an effective strategy, KGF-2 solution is widely used in the treatment of wounds in clinical applications. However, KGF-2 in solution cannot achieve sustained release, which results in drug loss and unnecessary waste. Polysaccharide hemostasis microspheres (PHMs) are an ideal drug loading platform due to their special "lotus seedpod surface-like" morphology and structure. Herein, to realize the controllable release of KGF-2, PHMs loaded with KGF-2 (KGF-2@PHMs) were prepared. It was found that the bioavailability of KGF-2 was improved greatly. Most importantly, KGF-2@PHMs can reduce inflammation and accelerate the wound healing process due to the controlled release of KGF-2. KGF-2@PHMs might be a potential alternative strategy for wound healing in future clinical applications.

Multiple roles of FGF10 in the regulation of corneal endothelial wound healing.

Corneal endothelial dysfunction usually induces corneal haze and oedema, which seriously affect visual function. The main therapeutic strategy for this condition is corneal transplantation, but the use of this strategy is limited by the shortage of healthy donor corneas. Compared with corneal transplantation, drug intervention is less invasive and more accessible; thus, finding an effective pharmaceutical alternative for cornea transplantation is critical for the treatment of corneal endothelial dysfunction. In this study, we established a rabbit scratch model to investigate the effect of fibroblast growth factor 10 (FGF10) on corneal endothelial wound healing. Results showed that FGF10 injection accelerated the recovery of corneal transparency and increased the protein expression levels of ZO1, Na+/K+-ATPase and AQP-1. Moreover, FGF10 significantly inhibited the expression levels of endothelial-to-mesenchymal transition proteins and reduced the expression levels of the proinflammatory factors IL-1ß and TNF-α in the anterior chamber aqueous humour. FGF10 also enhanced the Na+/K+-ATPase activity by enhancing mitochondrial function as a result of its direct interaction with its conjugate receptor. Thus, FGF10 could be a new pharmaceutical preparation as treatment for corneal endothelial dysfunction.

Cyclosporin A and FGF signaling support the proliferation/survival of mouse primordial germ cell-like cells in vitro†.

Primordial germ cells (PGCs) are the founding population of the germ cell lineage that undergo a multistep process to generate spermatozoa or oocytes. Establishing an appropriate culture system for PGCs is a key challenge in reproductive biology. By a chemical screening using mouse PGC-like cells (mPGCLCs), which were induced from mouse embryonic stem cells, we reported previously that forskolin and rolipram synergistically enhanced the proliferation/survival of mPGCLCs with an average expansion rate of ~20-fold. In the present study, we evaluated other chemicals or cytokines to see whether they would improve the current mPGCLC culture system. Among the chemicals and cytokines examined, in the presence of forskolin and rolipram, cyclosporin A (CsA) and fibroblast growth factors (FGFs: FGF2 and FGF10) effectively enhanced the expansion of mPGCLCs in vitro (~50-fold on average). During the expansion by CsA or FGFs, mPGCLCs comprehensively erased their DNA methylation to acquire a profile equivalent to that of gonadal germ cells in vivo, while maintaining their highly motile phenotype as well as their transcriptional properties as sexually uncommitted PGCs. Importantly, these mPGCLCs robustly contributed to spermatogenesis and produced fertile offspring. Furthermore, mouse PGCs (mPGCs) cultured with CsA ex vivo showed transcriptomes and DNA methylomes similar to those of cultured mPGCLCs. The improved culture system for mPGCLCs/mPGCs would be instructive for addressing key questions in PGC biology, including the mechanisms for germ cell migration, epigenetic reprogramming, and sex determination of the germline.

Topical Application of Fibroblast Growth Factor 10-PLGA Microsphere Accelerates Wound Healing via Inhibition of ER Stress.

There is a high incidence of acute and chronic skin defects caused by various reasons in clinically practice. The repair and functional reconstruction of skin defects have become a major clinical problem, which needs to be solved urgently. Previous studies have shown that fibroblast growth factor 10 (FGF10) plays a functional role in promoting the proliferation, migration, and differentiation of epithelial cells. However, little is known about the effect of FGF10 on the recovery process after skin damage. In this study, we found that the expression of endogenous FGF10 was increased during wound healing. We prepared FGF10-loaded poly(lactic-co-glycolic acid) (FGF10-PLGA) microspheres, and it could sustain release of FGF10 both in vitro and in vivo, accelerating wound healing. Further analysis revealed that compared with FGF10 alone, FGF10-PLGA microspheres significantly improved granulation formation, collagen synthesis, cell proliferation, and blood vessel density. In the meantime, we found that FGF10-PLGA microspheres inhibited the expression of endoplasmic reticulum (ER) stress markers. Notably, activating ER stress with tunicamycin (TM) reduced therapeutic effects of FGF10-PLGA microspheres in wound healing, whereas inhibition of ER stress with 4-phenyl butyric acid (4-PBA) improved the function of FGF10-PLGA microspheres. Taken together, this study indicates that FGF10-PLGA microspheres accelerate wound healing presumably through modulating ER stress.