HIF-1α induced FGF18 alleviates renal ischemia/reperfusion injury via YAP.

Acute kidney injury (AKI) is a devastating clinical condition characterized by an abrupt loss of renal function. The pathophysiology of AKI involves diverse processes and elements, of which survival and regeneration have been established to be significant hallmarks. And early studies have confirmed the fundamental role of FGFs in the regulation of AKI pathology, although the association between FGF18 and AKI still remains elusive. Our study demonstrates a substantial up-regulation of FGF18 in the renal tubules of mice subjected to ischemia. Notably, targeted overexpression of FGF18 effectively mitigates the impairment of kidney function induced by AKI. Mechanistically, FGF18 facilitates cell proliferation and anti-apoptosis in RTECs by enhancing the expression of YAP and facilitating its translocation to the nucleus. Aside from that, we also discovered that the substantial expression of FGF18 under ischemic conditions is HIF-1α dependent. This study aims to uncover the inherent mechanism behind the beneficial effects of FGF18 in attenuating AKI. By doing so, it aims to offer novel insights into the development of therapeutic strategies for AKI.

Fibroblast growth factor signalling regulates the development of tooth root.

Fibroblast growth factor (FGF) signalling plays a crucial role in the morphogenesis of multiple tissues including teeth. While the role of the signal has been studied in tooth crown development, little is known about root development. Of several FGF ligands involved in hard tissue formation, we suggest that FGF18 regulates the development of murine tooth roots. We implanted FGF18-soaked heparin beads into the lower first molar tooth buds at postnatal day 6 (P6), followed by transplantation under the kidney capsule. After 3 weeks, FGF18 significantly facilitated root elongation and periodontal tissue formation compared to the control. In situ hybridisation showed that Fgf18 transcripts were initially localised in the dental pulp along Hertwig's epithelial root sheath at P6 and P10 and subsequently in the dental follicle cells at P14. Fgf receptors were expressed in various dental tissues during these stages. In vitro analysis using the dental pulp stem cells revealed that FGF18 inhibited cell proliferation and decreased expression levels of osteogenic markers, Runx2, Alpl and Sp7. Consistently, after 1 week of kidney capsule transplantation, FGF18 application did not induce the expression of Sp7 and Bsp, but upregulated Periostin in the apical region of dental mesenchyme in the grafted molar. These findings suggest that FGF18 facilitates molar root development by regulating the calcification of periodontal tissues.

FGF18 alleviates sepsis-induced acute lung injury by inhibiting the NF-κB pathway.

BACKGROUND: Acute lung injury (ALI) is a devastating clinical disorder with a high mortality rate, and there is an urgent need for more effective therapies. Fibroblast growth factor 18 (FGF18) has potent anti-inflammatory properties and therefore has become a focus of research for the treatment of lung injury. However, the precise role of FGF18 in the pathological process of ALI and the underlying mechanisms have not been fully elucidated. METHODS: A mouse model of ALI and human umbilical vein endothelial cells (HUVEC) stimulated with lipopolysaccharide (LPS) was established in vivo and in vitro. AAV-FGF18 and FGF18 proteins were used in C57BL/6J mice and HUVEC, respectively. Vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and p65 protein levels were determined by western blotting or immunofluorescent staining. Afterward, related inhibitors were used to explore the potential mechanism by which FGF18 relieves inflammation. RESULTS: In this study, we found that FGF18 was significantly upregulated in LPS-induced ALI mouse lung tissues and LPS-stimulated HUVECs. Furthermore, our studies demonstrated that overexpressing FGF18 in the lung or HUVEC could significantly alleviate LPS-induced lung injury and inhibit vascular leakage. CONCLUSIONS: Mechanically, FGF18 treatment dramatically inhibited the NF-κB signaling pathway both in vivo and in vitro. In conclusion, these results indicate that FGF18 attenuates lung injury, at least partially, via the NF-κB signaling pathway and therefore may be a potential therapeutic target for ALI.

The synergistic mechanism of fibroblast growth factor 18 and integrin ß1 in rat abdominal aortic aneurysm repair.

BACKGROUND: Abdominal aortic aneurysms have a high mortality rate. While surgery is the preferred treatment method, the biological repair of abdominal aortic aneurysms is being increasingly studied. We performed cellular and animal experiments to investigate the simultaneous function and mechanism of fibroblast growth factor 18 and integrin ß1 in the biological repair of abdominal aortic aneurysms. METHODS: Endothelial and smooth muscle cells of rat arteries were used for the cellular experiments. Intracellular integrin ß1 expression was regulated through lentiviral transfection. Interventions with fibroblast growth factor 18 were determined according to the experimental protocol. Several methods were used to detect the expression of elastic fiber component proteins, cell proliferation, and migratory activity of endothelial and smooth muscle cells after different treatments. For animal experiments, abdominal aortic aneurysms were induced in rats by wrapping the abdominal aortae in sterile cotton balls soaked with CaCl2 solution. Fibroblast growth factor 18 was administered through tail vein injections. The local expression of integrin ß1 was regulated through lentiviral injections into the adventitia of the abdominal aortic aneurysms. The abdominal aortae were harvested for pathological examinations and tensile mechanical tests. RESULTS: The expression of integrin ß1 in endothelial and smooth muscle cells could be regulated effectively through lentiviral transfection. Animal and cellular experiments showed that fibroblast growth factor 18 + integrin ß1 could improve the expression of elastic fiber component proteins and enhance the migratory and proliferative activities of smooth muscle and endothelial cells. Moreover, animal experiments showed that fibroblast growth factor 18 + integrin ß1 could enhance the aortic integrity to withstand stretch of aortic aneurysm tissue. CONCLUSION: Fibroblast growth factor 18 + integrin ß1 improved the biological repair of abdominal aortic aneurysms in rats by increasing the expression of elastic proteins, improving the migratory and proliferative abilities of endothelial and smooth muscle cells, and improving aortic remodeling.

FGF18 modulates CTGF mRNA expression in cumulus-oocyte complexes and early bovine embryos: preliminary data.

The Hippo pathway is involved in the proliferation of intrafollicular cells and in early embryonic development, mainly because effectors of this pathway are key transcription regulators of genes such as CTGF and CYR61, which are involved in cell proliferation. Recent studies by our group found that fibroblast growth factor 18 (FGF18) is present in the fallopian tube during early embryonic development, leading to the hypothesis that FGF18 may have a role during embryonic development. Therefore, the aim of the following study was to determine whether FGF18 modulates the expression of Hippo pathway target genes, CTGF and CYR61, during oocyte maturation and early embryonic development. Three experiments were carried out, with in vitro maturation (IVM) of cumulus-oocyte complexes (COCs) and embryo culture. In experiment one, FGF18 (100 ng/ml) induced an increase (P < 0.05) in CTGF gene expression at 12 h post-exposure. In experiment two, FGF18 (100 ng/ml) induced a reduction (P < 0.05) in CTGF expression at 3 h post-exposure. In the third experiment, day 7 embryos exposed to FGF18 during oocyte IVM expressed greater CTGF mRNA abundance, whereas FGF18 exposure during embryo in vitro embryo culture did not alter CTGF expression in comparison with untreated controls. The preliminary data presented here show that FGF18 modulates CTGF expression in critical periods of oocyte nuclear maturation, cumulus expansion and early embryonic development in cattle.

The recombinant human fibroblast growth factor-18 (sprifermin) improves tendon-to-bone healing by promoting chondrogenesis in a rat rotator cuff repair model.

BACKGROUND: Rotator cuff healing is improved by reconstructing the fibrocartilaginous structure of the tendon-to-bone enthesis. Fibroblast growth factor (FGF)-18 (sprifermin) is a well-known growth factor that improves articular cartilage repair via its anabolic effect. This study aimed to investigate the effect of recombinant human FGF-18 (rhFGF-18) on the chondrogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) in vitro and tendon-to-bone healing in a rat model of rotator cuff repair. METHODS: Histological and reverse transcription-quantitative real-time polymerase chain reaction analyses of chondral pellets cultured with different concentrations of rhFGF-18 were performed. Bilateral detachment and repair of the supraspinatus tendon were performed on rats. The rats were administered 0.2 mL of sodium alginate (SA) hydrogel with (rhFGF-18/SA group, n = 12) or without (SA group, n = 12) 20 µg of rhFGF-18 into the repaired side. The simple repair group (n = 12) served as a control. At 4 and 8 weeks after surgery, histological analysis and biomechanical tests were performed. RESULTS: After chondrogenesis induction, compared with the control group, 10 ng/mL of rhFGF-18 increased pellet volume significantly (P = .002), with improved histological staining. It was noted that 10 ng/mL of rhFGF-18 upregulated the mRNA expression (relative ratio to control) of aggrecan (2.59 ± 0.29, P < .001), SRY-box transcription factor 9 (1.88 ± 0.05, P < .001), and type II collagen (1.46 ± 0.18, P = .009). At 4 and 8 weeks after surgery, more fibrocartilage and cartilaginous extracellular matrix was observed in rhFGF-18/SA-treated rats. The semiquantitative data from picrosirius red staining test were 31.1 ± 4.5 vs. 61.2 ± 4.1 at 4 weeks (P < .001) and 61.5 ± 2.8 vs. 80.5 ± 10.5 at 8 weeks (P = .002) (control vs. rhFGF-18/SA). Ultimate failure load (25.42 ± 3.61 N vs. 18.87 ± 2.71 N at 4 weeks and 28.63 ± 5.22 N vs. 22.15 ± 3.11 N at 8 weeks; P = .006 and P = .03, respectively) and stiffness (18.49 ± 1.38 N/mm vs. 14.48 ± 2.01 N/mm at 8 weeks, P = .01) were higher in the rhFGF-18/SA group than in the control group. CONCLUSION: rhFGF-18 promoted chondrogenesis in the hBMSCs in vitro. rhFGF-18/SA improved tendon-to-bone healing in the rats by promoting regeneration of the fibrocartilage enthesis. rhFGF-18 (sprifermin) may be beneficial in improving tendon-to-bone healing after rotator cuff repair.

Fibroblast growth factor 18 regulates steroidogenesis in fetal bovine ovarian tissue in vitro.

In cattle and other species, the fetal ovary is steroidogenically active before follicular development commences, and there is evidence that estradiol and progesterone inhibit follicle formation and activation. Estradiol levels decline sharply around the time of follicle formation. In the present study, we hypothesized that FGF10 and FGF18, which inhibit estradiol secretion from granulosa cells of antral follicles, also regulate fetal ovarian steroid production. Fetuses were collected at local abattoirs, and age determined by crown-rump length measurements. Real-time polymerase chain reaction assays with RNA extracted from whole ovaries revealed that the abundance of CYP19A1 messenger RNA (mRNA) decreased from 60 to 90 days of gestation, which is consistent with the decline in estradiol secretion previously observed. Immunohistochemistry revealed the presence of FGF18 in ovigerous cords in early gestation and in oocytes later in fetal age (≥150 days). The abundance of FGF18 mRNA increased after Day 90 gestation. Addition of recombinant FGF18 to fetal ovarian pieces inhibited estradiol and progesterone secretion in vitro, whereas FGF10 was without effect. Consistent with these results, FGF18 decreased levels of mRNA for CYP19A1 and CYP11A1 in ovarian pieces in vitro. These data suggest that FGF18 may be an intraovarian factor that regulates steroidogenesis in fetal ovaries.

Fibroblast growth factor 18 exerts anti-osteoarthritic effects through PI3K-AKT signaling and mitochondrial fusion and fission.

Osteoarthritis (OA) is a degenerative disease characterized by progressive loss of cartilage, osteophyte formation and subchondral bone sclerosis. Although some animal experiments have reported that fibroblast growth factor 18 (FGF18) attenuates cartilage degradation, the effect of FGF18 on chondrocytes and its underlying mechanism at the cellular level remain largely unknown. In this study, we found that an intra-articular injection of FGF18 attenuates cartilage degradation, increases Collagen II deposition and suppresses matrix metallopeptidase 13 (MMP13) expression in rat post-traumatic osteoarthritis (PTOA). At the cellular level, FGF18 promotes chondrocyte proliferation through PI3K-AKT signaling and migration through PI3K signaling. We found that FGF18 attenuates IL-1ß-induced apoptosis, restores mitochondrial function and reduces Reactive Oxygen Species (ROS) production through PI3K-AKT signaling. Moreover, the mitochondrial fusion and fission of chondrocytes were enhanced by a short duration of treatment (within 24 h) of IL-1ß and suppressed by prolonged treatment (48 h). FGF18 significantly enhances the mitochondrial fusion and fission, restoring mitochondrial function and morphology, and reduces ROS production. We also found that the FGFR1/FGFR3 ratio, which might contribute to the progression of osteoarthritis, was upregulated by IL-1ß and downregulated by FGF18. To the best of our knowledge, our data demonstrated the anti-osteoarthritic effect of FGF18 at the cellular level for the first time and suggested that PI3K-AKT signaling and mitochondrial fusion and fission might play critical roles during the process. Our study proved that FGF18 might be a promising drug for the treatment of early stage osteoarthritis and is worth further study.

Fibrin-Hyaluronic Acid Hydrogel (RegenoGel) with Fibroblast Growth Factor-18 for In Vitro 3D Culture of Human and Bovine Nucleus Pulposus Cells.

We investigated the effects of a fibrin-hyaluronic acid hydrogel (FBG-HA) and fibroblast growth factor 18 (FGF-18) for nucleus pulposus (NP) regeneration. Healthy bovine (n = 4) and human degenerated NP cells (n = 4) were cultured for 14 days in FBG-HA hydrogel with FGF-18 (∆51-mutant or wild-type) in the culture medium. Gene expression, DNA content, and glycosaminoglycan (GAG) synthesis were evaluated on day 7 and 14. Additionally, histology was performed. Human NP cells cultured in FBG-HA hydrogel showed an increase in collagen type II (COL2) and carbonic anhydrase XII (CA12) gene expression after 14 or 7 days of culture, respectively. GAG release into the conditioned medium increased over 14 days. Healthy bovine NP cells showed increased gene expression of ACAN from day 7 to day 14. Wild type FGF-18 up-regulated CA12 gene expression of human NP cells. Histology revealed an increase of proteoglycan deposition upon FGF-18 stimulation in bovine but not in human NP cells. The FBG-HA hydrogel had a positive modulatory effect on human degenerated NP cells. Under the tested conditions, no significant effect of FGF-18 was observed on cell proliferation or GAG synthesis in human NP cells.

Striking a new path in reducing cartilage breakdown: combination of antioxidative therapy and chondroanabolic stimulation after blunt cartilage trauma.

Cartilage injury can trigger crucial pathomechanisms, including excessive cell death and expression of matrix-destructive enzymes, which contribute to the progression of a post-traumatic osteoarthritis (PTOA). With the intent to create a novel treatment strategy for alleviating trauma-induced cartilage damage, we complemented a promising antioxidative approach based on cell and chondroprotective N-acetyl cysteine (NAC) by chondroanabolic stimulation. Overall, three potential pro-anabolic growth factors - IGF-1, BMP7 and FGF18 - were tested comparatively with and without NAC in an ex vivo human cartilage trauma-model. For that purpose, full-thickness cartilage explants were subjected to a defined impact (0.59 J) and subsequently treated with the substances. Efficacy of the therapeutic approaches was evaluated by cell viability, as well as various catabolic and anabolic biomarkers, representing the present matrix turnover. Although monotherapy with NAC, FGF18 or BMP7 significantly prevented trauma-induced cell dead and breakdown of type II collagen, combination of NAC and one of the growth factors did not yield significant benefit as compared to NAC alone. IGF-1, which possessed only moderate cell protective and no chondroprotective qualities after cartilage trauma, even reduced NAC-mediated cell and chondroprotection. Despite significant promotion of type II collagen expression by IGF-1 and BMP7, addition of NAC completely suppressed this chondroanabolic effect. All in all, NAC and BMP7 emerged as best combination. As our findings indicate limited benefits of the simultaneous multidirectional therapy, a sequential application might circumvent adverse interferences, such as suppression of type II collagen biosynthesis, which was found to be reversed 7 days after NAC withdrawal.

A Bionic Thermosensitive Sustainable Delivery System for Reversing the Progression of Osteoarthritis by Remodeling the Joint Homeostasis.

Although the pathogenesis of osteoarthritis (OA) is unclear, inflammatory cytokines are related to its occurrence. However, few studies focused on the therapeutic strategies of regulating joint homeostasis by simultaneously remodeling the anti-inflammatory and immunomodulatory microenvironments. Fibroblast growth factor 18 (FGF18) is the only disease-modifying OA drug (DMOAD) with a potent ability and high efficiency in maintaining the phenotype of chondrocytes within cell culture models. However, its potential role in the immune microenvironment remains unknown. Besides, information on an optimal carrier, whose interface and chondral-biomimetic microenvironment mimic the native articular tissue, is still lacking, which substantially limits the clinical efficacy of FGF18. Herein, to simulate the cartilage matrix, chondroitin sulfate (ChS)-based nanoparticles (NPs) are integrated into poly(D, L-lactide)-poly(ethylene glycol)-poly(D, L-lactide) (PLEL) hydrogels to develop a bionic thermosensitive sustainable delivery system. Electrostatically self-assembled ChS and ε-poly-l-lysine (EPL) NPs are prepared for the bioencapsulation of FGF18. This bionic delivery system suppressed the inflammatory response in interleukin-1ß (IL-1ß)-mediated chondrocytes, promoted macrophage M2 polarization, and inhibited M1 polarization, thereby ameliorating cartilage degeneration and synovitis in OA. Thus, the ChS-based hydrogel system offers a potential strategy to regulate the chondrocyte-macrophage crosstalk, thus re-establishing the anti-inflammatory and immunomodulatory microenvironment for OA therapy.

Circulating FGF18 is decreased in pleural mesothelioma but not correlated with disease prognosis.

BACKGROUND: Pleural mesothelioma (PM) is a relatively rare malignancy with limited treatment options and dismal prognosis. We have previously found elevated FGF18 expression in PM tissue specimens compared with normal mesothelium. The objective of the current study was to further explore the role of FGF18 in PM and evaluate its suitability as a circulating biomarker. METHODS: FGF18 mRNA expression was analyzed by real-time PCR in cell lines and in silico in datasets from the Cancer Genome Atlas (TCGA). Cell lines overexpressing FGF18 were generated by retroviral transduction and cell behavior was investigated by clonogenic growth and transwell assays. Plasma was collected from 40 PM patients, six patients with pleural fibrosis, and 40 healthy controls. Circulating FGF18 was measured by ELISA and correlated to clinicopathological parameters. RESULTS: FGF18 showed high mRNA expression in PM and PM-derived cell lines. PM patients with high FGF18 mRNA expression showed a trend toward longer overall survival (OS) in the TCGA dataset. In PM cells with low endogenous FGF18 expression, forced overexpression of FGF18 resulted in reduced growth but increased migration. Surprisingly, despite the high FGF18 mRNA levels observed in PM, circulating FGF18 protein was significantly lower in PM patients and patients with pleural fibrosis than in healthy controls. No significant association of circulating FGF18 with OS or other disease parameters of PM patients was observed. CONCLUSIONS: FGF18 is not a prognostic biomarker in PM. Its role in PM tumor biology and the clinical significance of decreased plasma FGF18 in PM patients warrant further investigation.

Augmented effect of fibroblast growth factor 18 in bone morphogenetic protein 2-induced calvarial bone healing by activation of CCL2/CCR2 axis on M2 macrophage polarization.

Fibroblast growth factor (FGF) signaling plays essential roles in various biological events. FGF18 is one of the ligands to be associated with osteogenesis, chondrogenesis and bone healing. The mouse critical-sized calvarial defect healing induced by the bone morphogenetic protein 2 (BMP2)-hydrogel is stabilized when FGF18 is added. Here, we aimed to investigate the role of FGF18 in the calvarial bone healing model. We first found that FGF18 + BMP2 hydrogel application to the calvarial bone defect increased the expression of anti-inflammatory markers, including those related to tissue healing M2 macrophage (M2-Mø) prior to mineralized bone formation. The depletion of macrophages with clodronate liposome hindered the FGF18 effect. We then examined how FGF18 induces M2-Mø polarization by using mouse primary bone marrow (BM) cells composed of macrophage precursors and BM stromal cells (BMSCs). In vitro studies demonstrated that FGF18 indirectly induces M2-Mø polarization by affecting BMSCs. Whole transcriptome analysis and neutralizing antibody treatment of BMSC cultured with FGF18 revealed that chemoattractant chemokine (c-c motif) ligand 2 (CCL2) is the major mediator for M2-Mø polarization. Finally, FGF18-augmented activity toward favorable bone healing with BMP2 was diminished in the calvarial defect in Ccr2-deleted mice. Altogether, we suggest a novel role of FGF18 in M2-Mø modulation via stimulation of CCL2 production in calvarial bone healing.

Cucurbitacin promotes hair growth in mice by inhibiting the expression of fibroblast growth factor 18.

Background: The inhibition of fibroblast growth factor 18 (FGF18) promotes the transition of hair follicles (HFs) from the telogen phase to the anagen phase. Cucurbitacin has been shown to have a good effect in promoting hair cell growth. This study explored the potential effect of cucurbitacin on hair growth and its effect on FGF18 expression in mice. Methods: Male C57BL/6J mice were randomly divided into the following two groups: (I) the vehicle group; and (II) the cucurbitacin group. Matrix cream and cucurbitacin cream were applied to the depilated skin on the back of the vehicle group mice and the cucurbitacin group mice, respectively. On days 3, 6, 9, 12, 15, and 18, the hair growth in the depilated dorsal skin of the mice was recorded with a digital camera and a HF detector, and the HF cycle status of the mice was observed by hematoxylin and eosin (H&E) staining. In addition, the level of FGF18 messenger ribonucleic acid (mRNA) in the dorsal skin was measured on days 15 and 18 by quantitative real-time polymerase chain reaction (qRT-PCR), while the level of FGF18 protein was measured by western blot and immunofluorescence staining. Results: The dorsal skin to which the cucurbitacin cream was applied began to darken on day 6 and grew hairs on day 9, which was 3 days earlier than the dorsal skin to which the matrix cream was applied. The H&E staining revealed a transition from the telogen phase to the anagen phase 3 days earlier for the cucurbitacin cream-treated skin than the matrix cream-treated skin. In addition, the skin treated with cucurbitacin cream also showed a significant decrease in FGF18 mRNA as seen by qRT-PCR, and reduced FGF18 protein levels as detected by western blot and immunofluorescence staining compared to the skin treated with matrix cream only. Conclusions: Cucurbitacin significantly reduced the levels of FGF18 mRNA and protein in the dorsal skin of mice to accelerate the HFs to enter the anagen phase earlier, thereby promoting the regeneration of hair. Thus, cucurbitacin can be considered a new and valuable agent for the development of anti-hair loss products.

Lentivirus-mediated transfer of gene encoding fibroblast growth factor-18 inhibits intervertebral disc degeneration.

Fibroblast growth factor 18 (FGF-18) is a well-characterized anabolic growth factor involved in cartilage homeostasis. However, the effect of FGF-18 on intervertebral disc (IVD) degeneration has not been investigated. The present study aimed to investigate the role of FGF-18 in the process of rabbit IVD degeneration. In vitro, primary nucleus pulposus cells (NPs) were cultured and transfected with a lentivirus. Tert-butyl hydroperoxide (TBHP) was used to induce apoptosis in NPs on the second passage, while overexpression of FGF-18 in NPs attenuated TBHP-induced apoptosis. A rabbit annular puncture model was generated to induce IVD degeneration in vivo. The discs were injected with an FGF-18-overexpression lentivirus or a negative control lentivirus. In the sham group, the discs were exposed and not punctured. Disc degeneration was evaluated using H&E staining and a histological grading system. Reverse transcription-quantitative PCR was used to detect the expression of the extracellular matrix-degrading enzymes matrix metalloproteinase-3 (MMP-3) and A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5). Nucleus pulposus apoptosis was detected via western blotting, immunohistochemical methods and TUNEL staining. Histologic examination showed that disc degeneration was attenuated after FGF-18 overexpression treatment. At 8 weeks after surgery, the expression of MMP-3 and ADAMTS-5 in the annular puncture groups was higher compared with in the sham group. FGF-18 treatment inhibited the expression of MMP-3 and ADAMTS-5 at the mRNA level. Western blot assays indicated that the expression level of Bax was significantly reduced in the FGF-18 groups, and that the expression level of Bcl-2 was significantly increased compared with those in the control group. Moreover, immunohistochemical analysis indicated that the FGF-18 group exhibited a lower percentage of cleaved caspase 3-positive NPs. Quantification of the TUNEL staining demonstrated that the FGF-18 group had fewer apoptotic NPs than the control group. These findings indicated that FGF-18 could delay IVD degeneration by inhibiting the apoptosis of NPs and the expression of matrix-degrading enzymes.

Enhanced chondrogenic phenotype of primary bovine articular chondrocytes in Fibrin-Hyaluronan hydrogel by multi-axial mechanical loading and FGF18.

Current treatments for cartilage lesions are often associated with fibrocartilage formation and donor site morbidity. Mechanical and biochemical stimuli play an important role in hyaline cartilage formation. Biocompatible scaffolds capable of transducing mechanical loads and delivering bioactive instructive factors may better support cartilage regeneration. In this study we aimed to test the interplay between mechanical and FGF-18 mediated biochemical signals on the proliferation and differentiation of primary bovine articular chondrocytes embedded in a chondro-conductive Fibrin-Hyaluronan (FB/HA) based hydrogel. Chondrocytes seeded in a Fibrin-HA hydrogel, with or without a chondro-inductive, FGFR3 selective FGF18 variant (FGF-18v) were loaded into a joint-mimicking bioreactor applying controlled, multi-axial movements, simulating the natural movements of articular joints. Samples were evaluated for DNA content, sulphated glycosaminoglycan (sGAG) accumulation, key chondrogenic gene expression markers and histology. Under moderate loading, samples produced particularly significant amounts of sGAG/DNA compared to unloaded controls. Interestingly there was no significant effect of FGF-18v on cartilage gene expression at rest. Following moderate multi-axial loading, FGF-18v upregulated the expression of Aggrecan (ACAN), Cartilage Oligomeric Matrix Protein (COMP), type II collagen (COL2) and Lubricin (PRG4). Moreover, the combination of load and FGF-18v, significantly downregulated Matrix Metalloproteinase-9 (MMP-9) and Matrix Metaloproteinase-13 (MMP-13), two of the most important factors contributing to joint destruction in OA. Biomimetic mechanical signals and FGF-18 may work in concert to support hyaline cartilage regeneration and repair. STATEMENT OF SIGNIFICANCE: Articular cartilage has very limited repair potential and focal cartilage lesions constitute a challenge for current standard clinical procedures. The aim of the present research was to explore novel procedures and constructs, based on biomaterials and biomechanical algorithms that can better mimic joints mechanical and biochemical stimulation to promote regeneration of damaged cartilage. Using a hydrogel-based platform for chondrocyte 3D culture revealed a synergy between mechanical forces and growth factors. Exploring the mechanisms underlying this mechano-biochemical interplay may enhance our understanding of cartilage remodeling and the development of new strategies for cartilage repair and regeneration.

Emerging therapeutic agents in osteoarthritis.

Osteoarthritis (OA) is the most common joint disorder and a leading cause of disability. Current treatments for OA can improve symptoms but do not delay the progression of disease. In the last years, much effort has been devoted to developing new treatments for OA focused on pain control, inflammatory mediators or degradation of articular tissues. Although promising results have been obtained in ex vivo studies and animal models of OA, few of these agents have completed clinical trials. Available clinical data support the interest of nerve growth factor as a target in pain control as well as the disease-modifying potential of inhibitors of Wnt signaling or catabolic enzymes such as aggrecanases and cathepsin K, and anabolic strategies like fibroblast growth factor-18 or cellular therapies. Carefully controlled studies in patients selected according to OA phenotypes and with a long follow-up will help to confirm the relevance of these new approaches as emerging therapeutic treatments in OA.

Roles of FGF8 subfamily in embryogenesis and oral­maxillofacial diseases (Review).

Fibroblast growth factors (FGFs) are diffusible polypeptides released by a variety of cell types. FGF8 subfamily members regulate embryonic development processes through controlling progenitor cell growth and differentiation, and are also functional in adults in tissue repair to maintain tissue homeostasis. FGF8 family members exhibit unique binding affinities with FGF receptors and tissue distribution patterns. Increasing evidence suggests that, by regulating multiple cellular signaling pathways, alterations in the FGF8 subfamily are involved in craniofacial development, odontogenesis, tongue development and salivary gland branching morphogenesis. Aberrant FGF signaling transduction, caused by mutations as well as abnormal expression or isoform splicing, plays an important role in the development of oral diseases. Targeting FGF8 subfamily members provides a new promising strategy for the treatment of oral diseases. The aim of this review was to summarize the aberrant regulations of FGF8 subfamily members and their potential implications in oral­maxillofacial diseases.

Released fibroblast growth factor18 from a collagen membrane induces osteoblastic activity involved with downregulation of miR-133a and miR-135a.

We have developed a unique delivery system of growth factors using collagen membranes (CMs) to induce bone regeneration. We hypothesized that fibroblast growth factor18 (FGF-18), a pleiotropic protein that stimulates proliferation in several tissues, can be a good candidate to use our delivery system for bone regeneration. Cell viability, cell proliferation, alkaline phosphatase activity, mineralization, and marker gene expression of osteoblastic differentiation were evaluated after mouse preosteoblasts were cultured with a CM containing FGF-18, a CM containing platelet-derived growth factor, or a CM alone. Furthermore, expression of microRNA, especially miR-133a and miR-135a involving inhibition of osteogenic factors, was measured in preosteoblasts with CM/FGF-18 or CM alone. A sustained release of FGF-18 from the CM was observed over 21 days. CM/FGF-18 significantly promoted cell proliferation, alkaline phosphatase activity, and mineralization compared to CM alone. Gene expression of type I collagen, runt-related transcription factor 2, osteocalcin, Smad5, and osteopontin was significantly upregulated in CM/FGF-18 compared to CM alone, and similar to CM/platelet-derived growth factor. Additionally, CM/FGF-18 downregulated expression of miR-133a and miR-135a. These results suggested that released FGF-18 from a CM promotes osteoblastic activity involved with downregulation of miR-133a and miR-135a.

Effects and related mechanisms of histone deacetylase inhibitors on the proliferation of choroidal melanoma C918 cell line / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To elucidate the effect of histone deacetylase(HDAC)inhibitor suberoylanilide hydroxamic acid(SAHA)on the proliferation of choroidal melanoma(CM)cell line C918 and to explore the related mechanism.METHODS: Inverted fluorescence microscope was used to observe the effect of different concentrations of SAHA(0.625, 1.25 or 2.5 μmol/L)on the morphology of C918 cell. The cell viability was detected by cholecystokinin octapeptide(CCK-8)assay. Plate clone formation assay and EdU staining were carried out to measure the effect of SAHA on the cell proliferation. Meanwhile, the expressions of cell proliferation-related proteins including c-Myc, CyclinA2 and CDK2, and histone deacetylase 7(HDAC7)and fibroblast growth factor 18(FGF18)were detected by Western blot.RESULTS: Compared with the control group, the cell density was reduced in SAHA. SAHA could also promote cell shrinkage, and the inhibition on cell was in a concentration-dependent manner. CCK-8 assay showed that SAHA treatment decreased cell viability in a dose-dependent manner and the inhibition rate was 80% when SAHA at 2.5 μmol/L. Compared with the control group, Western blot showed that SAHA could suppress the expression of cell proliferation proteins including c-Myc, CyclinA2 and CDK2 in a dose-dependent manner. In addition, 1.25 μmol/L SAHA significantly decreased the numbers of EdU staining positive cells and cell clones. More importantly, SAHA could dose-dependently decrease the expression of HDAC7 and FGF18 compared with control group.CONCLUSION: SAHA could inhibit the proliferation of CM cell line C918 by inhibiting the HDAC7/FGF18 signaling pathway.