Upregulation of FGF9 and NOVA1 in cancer-associated fibroblasts promotes cell proliferation, invasion and migration of triple negative breast cancer.

Cancer-associated fibroblasts (CAFs) play a pivotal role in cancer progression. This study aimed to explore the roles of CAFs-derived Fibroblast growth factor 9 (FGF9) and Neuro-oncological ventral antigen 1 (NOVA1) in triple negative breast cancer (TNBC) progression. MDA-MB-231 and BT-549 cells were cocultured with CAF conditioned-medium (CAF-CM) or normal fibroblasts conditioned-medium (NF-CM). MTT, EdU, colony formation, wound healing, transwell migration, and invasion assays were employed to determine cell proliferation, migration and invasion, respectively. Western blot and RT-qPCR were carried out to examine the protein and mRNA expression of FGF9 and NOVA1. Xenograft tumor experiments were conducted to evaluate the effects of CAFs, FGF9, and NOVA1 on tumor growth in vivo. Our results showed that CAFs significantly promoted the proliferation, invasion, and migration of TNBC cells. FGF9 and NOVA1 were significantly upregulated in TNBC CAFs, tissues and cells. CAF-CM also could increase the expression of FGF9 and NOVA1 in TNBC cells. Knockdown of FGF9 or NOVA1 could hamper cell proliferation, invasion, migration, and EMT of TNBC cells. Moreover, CAFs with FGF9/NOVA1 knockdown also could inhibit TNBC progression. Besides, CAFs significantly accelerated tumor growth in vivo, which was blocked by FGF9/NOVA1 knockdown in nude mice. In conclusion, our results indicated the tumor-promoting role of CAFs in TNBC progression. FGF9 and NOVA1 upregulation in CAFs induced cell proliferation, migration and invasion in vitro, and facilitated tumor growth in vivo in TNBC development.

Regulatory Effects of FGF9 on Dermal Papilla Cell Proliferation in Small-Tailed Han Sheep.

Fibroblast growth factor 9 (FGF9) is crucial for the growth and development of hair follicles (HFs); however, its role in sheep wool growth is unknown. Here, we clarified the role of FGF9 in HF growth in the small-tailed Han sheep by quantifying FGF9 expression in skin tissue sections collected at different periods. Moreover, we evaluated the effects of FGF9 protein supplementation on hair shaft growth in vitro and FGF9 knockdown on cultured dermal papilla cells (DPCs). The relationship between FGF9 and the Wnt/ß-catenin signaling pathway was examined, and the underlying mechanisms of FGF9-mediated DPC proliferation were investigated. The results show that FGF9 expression varies throughout the HF cycle and participates in wool growth. The proliferation rate and cell cycle of FGF9-treated DPCs substantially increase compared to that of the control group, and the mRNA and protein expression of CTNNB1, a Wnt/ß-catenin signaling pathway marker gene, is considerably lower than that in the control group. The opposite occurs in FGF9-knockdown DPCs. Moreover, other signaling pathways are enriched in the FGF9-treated group. In conclusion, FGF9 accelerates the proliferation and cell cycle of DPCs and may regulate HF growth and development through the Wnt/ß-catenin signaling pathway.

Inhibition of miR-182-5p Targets FGF9 to Alleviate Osteoarthritis.

Background: The pathogenesis of osteoarthritis (OA) is complex and there is no specific drug for treatment. The aim of this study was to identify the molecular targets of OA therapy, focusing on the expression and biological functions of miR-182-5p and its target genes in OA. Methods: miR-182-5p and fibroblast growth factor 9 (FGF9) were overexpressed or knocked down in IL-1ß-induced chondrocytes. An OA knee model was performed by surgically destroying the medial meniscus. The gene expression of miR-182-5p and FGF9 was calculated. The protein FGF9 was tested by western blotting. Cell counting kit-8 (CCK8), plate cloning assay, and flow cytometry were conducted to evaluate cell proliferation and apoptosis. The expression of inflammatory factors, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and interleukin (IL)-8, was evaluated using enzyme-linked immunosorbent assay (ELISA). Dual-luciferase reporter assays validated the targeting relationship between miR-182-5p and FGF9. Hematoxylin-eosin (HE) and safranin O-fast Green (S-O) staining were utilized to access cartilage damage. Ki67 expression in cartilage was detected using immunohistochemistry (IHC). TdT-mediated dUTP nick-end labeling (TUNEL) assays were used to calculate the apoptosis rate of cartilage. Results: The expression of miR-182-5p was upregulated, and FGF9 was downregulated in the IL-1ß-induced chondrocytes. OA chondrocytes proliferation ability in the miR-182-5p mimics group was decreased, and the apoptosis rate and inflammatory factor were increased. Transfection with miR-182-5p inhibitor increased the proliferative ability and decreased the apoptosis rate in the IL-1ß-induced chondrocytes. Transfection with miR-182-5p inhibitor reversed IL-1ß-induced inflammatory factor release in chondrocytes. Targeted binding sites existed between miR-182-5p and FGF9. After overexpression of FGF9, the miR-182-5p effect on OA chondrocytes was reversed. The hyaline cartilage thickness and proteoglycan content decreased in OA rats, and this was reversed by miR-182-5p inhibitor treatment. Conclusions: miR-182-5p expression levels were increased in OA chondrocytes and regulated chondrocyte proliferation, apoptosis, and inflammation by targeting FGF9. miR-182-5p is a potential gene for OA treatment.

FGF4 and FGF9 have synergistic effects on odontoblast differentiation.

The purpose of this study was to investigate whether fibroblast growth factor 4 (FGF4) and FGF9 are active in dentin differentiation. Dentin matrix protein 1 (Dmp1) -2A-Cre transgenic mice, which express the Cre-recombinase in Dmp1-expressing cells, were crossed with CAG-tdTomato mice as reporter mouse. The cell proliferation and tdTomato expressions were observed. The mesenchymal cell separated from neonatal molar tooth germ were cultured with or without FGF4, FGF9, and with or without their inhibitors ferulic acid and infigratinib (BGJ398) for 21 days. Their phenotypes were evaluated by cell count, flow cytometry, and real-time PCR. Immunohistochemistry for FGFR1, 2, and 3 expression and the expression of DMP1 were performed. FGF4 treatment of mesenchymal cells obtained promoted the expression of all odontoblast markers. FGF9 failed to enhance dentin sialophosphoprotein (Dspp) expression levels. Runt-related transcription factor 2 (Runx2) was upregulated until day 14 but was downregulated on day 21. Compared to Dmp1-negative cells, Dmp1-positive cells expressed higher levels of all odontoblast markers, except for Runx2. Simultaneous treatment with FGF4 and FGF9 had a synergistic effect on odontoblast differentiation, suggesting that they may play a role in odontoblast maturation.

Targeted deletion of Fgf9 in tendon disrupts mineralization of the developing enthesis.

The enthesis is a transitional tissue between tendon and bone that matures postnatally. The development and maturation of the enthesis involve cellular processes likened to an arrested growth plate. In this study, we explored the role of fibroblast growth factor 9 (Fgf9), a known regulator of chondrogenesis and vascularization during bone development, on the structure and function of the postnatal enthesis. First, we confirmed spatial expression of Fgf9 in the tendon and enthesis using in situ hybridization. We then used Cre-lox recombinase to conditionally knockout Fgf9 in mouse tendon and enthesis (Scx-Cre) and characterized enthesis morphology as well as mechanical properties in Fgf9ScxCre and wild-type (WT) entheses. Fgf9ScxCre mice had smaller calcaneal and humeral apophyses, thinner cortical bone at the attachment, increased cellularity, and reduced failure load in mature entheses compared to WT littermates. During postnatal development, we found reduced chondrocyte hypertrophy and disrupted type X collagen (Col X) in Fgf9ScxCre entheses. These findings support that tendon-derived Fgf9 is important for functional development of the enthesis, including its postnatal mineralization. Our findings suggest the potential role of FGF signaling during enthesis development.

Application of an in silico approach identifies a genetic locus within ITGB2, and its interactions with HSPG2 and FGF9, to be associated with anterior cruciate ligament rupture risk.

We developed a Biomedical Knowledge Graph model that is phenotype and biological function-aware through integrating knowledge from multiple domains in a Neo4j, graph database. All known human genes were assessed through the model to identify potential new risk genes for anterior cruciate ligament (ACL) ruptures and Achilles tendinopathy (AT). Genes were prioritised and explored in a case-control study comparing participants with ACL ruptures (ACL-R), including a sub-group with non-contact mechanism injuries (ACL-NON), to uninjured control individuals (CON). After gene filtering, 3376 genes, including 411 genes identified through previous whole exome sequencing, were found to be potentially linked to AT and ACL ruptures. Four variants were prioritised: HSPG2:rs2291826A/G, HSPG2:rs2291827G/A, ITGB2:rs2230528C/T and FGF9:rs2274296C/T. The rs2230528 CC genotype was over-represented in the CON group compared to ACL-R (p < 0.001) and ACL-NON (p < 0.001) and the TT genotype and T allele were over-represented in the ACL-R group and ACL-NON compared to CON (p < 0.001) group. Several significant differences in distributions were noted for the gene-gene interactions: (HSPG2:rs2291826, rs2291827 and ITGB2:rs2230528) and (ITGB2:rs2230528 and FGF9:rs2297429). This study substantiates the efficiency of using a prior knowledge-driven in silico approach to identify candidate genes linked to tendon and ACL injuries. Our biomedical knowledge graph identified and, with further testing, highlighted novel associations of the ITGB2 gene which has not been explored in a genetic case control association study, with ACL rupture risk. We thus recommend a multistep approach including bioinformatics in conjunction with next generation sequencing technology to improve the discovery potential of genomics technologies in musculoskeletal soft tissue injuries.HighlightsA biomedical knowledge graph was modelled for musculoskeletal soft tissue injuries to efficiently identify candidate genes for genetic susceptibility analyses.The biomedical knowledge graph and sequencing data identified potential biologically relevant variants to explore susceptibility to common tendon and ligament injuries. Specifically genetic variants within the ITGB2 and FGF9 genes were associated with ACL risk.Novel allele combinations (HSPG2-ITGB2 and ITGB2-FGF9) showcase the potential effect of ITGB2 in influencing risk of ACL rupture.

FGF9 variant in 46,XY DSD patient suggests a role for dimerization in sex determination.

46,XY gonadal dysgenesis (GD) is a Disorder/Difference of Sex Development (DSD) that can present with phenotypes ranging from ambiguous genitalia to complete male-to-female sex reversal. Around 50% of 46,XY DSD cases receive a molecular diagnosis. In mice, Fibroblast growth factor 9 (FGF9) is an important component of the male sex-determining pathway. Two FGF9 variants reported to date disrupt testis development in mice, but not in humans. Here, we describe a female patient with 46,XY GD harbouring the rare FGF9 variant (missense mutation), NM_002010.2:c.583G > A;p.(Asp195Asn) (D195N). By biochemical and cell-based approaches, the D195N variant disrupts FGF9 protein homodimerisation and FGF9-heparin-binding, and reduces both Sertoli cell proliferation and Wnt4 repression. XY Fgf9D195N/D195N foetal mice show a transient disruption of testicular cord development, while XY Fgf9D195N/- foetal mice show partial male-to-female gonadal sex reversal. In the general population, the D195N variant occurs at an allele frequency of 2.4 × 10-5 , suggesting an oligogenic basis for the patient's DSD. Exome analysis of the patient reveals several known and novel variants in genes expressed in human foetal Sertoli cells at the time of sex determination. Taken together, our results indicate that disruption of FGF9 homodimerization impairs testis determination in mice and, potentially, also in humans in combination with other variants.

FGF9 Promotes Expression of HAS2 in Palatal Elevation via the Wnt/ß-Catenin/TCF7L2 Pathway.

BACKGROUND: Fgf9 mutation was found in cleft palate patients. Our previous study indicated that Fgf9 promotes timely elevation of palate by regulating hyaluronic acid (HA) accumulation at embryonic day 13.5 (E13.5). HA is synthesized by hyaluronic acid synthases (HAS) isoforms 1, 2, or 3. However, how FGF9 regulates HA in palatogenesis is still unclear. METHODS: Using Ddx4-Cre mice, we generated the Fgf9-/- mouse model (with exon 2 deletion). Immunohistochemistry was used to detect the location and expression of HAS2 in WT and the Fgf9-/- palate at E13.5. We also predicted the association between Fgf9 and Has2 within the developing palate by performing a bioinformatics analysis. The expression of ß-catenin, HAS2, and TCF7L2 were verified by Western blotting after knockout of Fgf9. Rescue experiments were performed by ELISA in vitro. RESULTS: Fgf9-/- mice exhibited 100% penetrance of the cleft palate. A knockout of Fgf9 confirmed that HAS2 and TCF7L2 expression was positively correlated with FGF9. TCF7L2 binds to the Has2 promoter, exhibiting the high specificity predicted by JASPAR. Additionally, increased HA expression by BML-284, TCF-dependent agonist, was blocked in Fgf9-/- palate because of the significant decline in TCF7L2 expression. CONCLUSIONS: FGF9 promotes HAS2 expression via Wnt/ß-catenin/TCF7L2 pathway with TCF7L2 activating transcription of Has2 in the palate.

Loss of Raptor induces Sertoli cells into an undifferentiated state in mice.

In mammals, testis development is triggered by the expression of the sex-determining Y-chromosome gene SRY to commit the Sertoli cell (SC) fate at gonadal sex determination in the fetus. Several genes have been identified to be required to promote the testis pathway following SRY activation (i.e., SRY box 9 (SOX9)) in an embryo; however, it largely remains unknown about the genes and the mechanisms involved in stabilizing the testis pathway after birth and throughout adulthood. Herein, we report postnatal males with SC-specific deletion of Raptor demonstrated the absence of SC unique identity and adversely acquired granulosa cell-like characteristics, along with loss of tubular architecture and scattered distribution of SCs and germ cells. Subsequent genome-wide analysis by RNA sequencing revealed a profound decrease in the transcripts of testis genes (i.e., Sox9, Sox8, and anti-Mullerian hormone (Amh)) and, conversely, an increase in ovary genes (i.e., LIM/Homeobox gene 9 (Lhx9), Forkhead box L2 (Foxl2) and Follistatin (Fst)); these changes were further confirmed by immunofluorescence and quantitative reverse-transcription polymerase chain reaction. Importantly, co-immunofluorescence demonstrated that Raptor deficiency induced SCs dedifferentiation into a progenitor state; the Raptor-mutant gonads showed some ovarian somatic cell features, accompanied by enhanced female steroidogenesis and elevated estrogen levels, yet the zona pellucida 3 (ZP3)-positive terminally feminized oocytes were not observed. In vitro experiments with primary SCs suggested that Raptor is likely involved in the fibroblast growth factor 9 (FGF9)-induced formation of cell junctions among SCs. Our results established that Raptor is required to maintain SC identity, stabilize the male pathway, and promote testis development.

Novel FGF9 variant contributes to multiple synostoses syndrome 3.

Multiple synostoses syndromes (SYNS) are autosomal dominant syndromes characterized by multiple joint fusions commonly involving the carpal-tarsal, interphalangeal, humeroradial, and cervical spine joints. They display genetic heterogeneity with pathogenic variants reported in four separate genes (NOG, GDF5, FGF9, and GDF6) defining four different SYNS forms. FGF9 variants have been reported in SYNS3, a SYNS with multiple synostoses, normal cognition, normal hearing, and craniosynostosis. Here, we report a novel FGF9 c.569G > C p.(Arg190Thr) variant identified by whole-exome sequencing in a patient with multiple bony abnormalities. The patient initially presented with elbow instability and decreased range of motion. Imaging revealed bilateral radial head deformities, carpal-tarsal fusions, brachydactyly, and osteoarthritis of the sacroiliac joints. In silico protein modeling of the identified FGF9 variant predicts decreased stability of ligand-receptor binding supporting the pathogenicity of this finding. This finding expands the repertoire of FGF9 variants and phenotypic information reported for SYNS3 and suggest that genotype phenotype correlations due to localization seem less likely and more so due to the consequence of the pathogenic variant on the receptor. This is useful in the counseling in families as more de novo variants emerge.

Downregulated exosome-associated gene FGF9 as a novel diagnostic and prognostic target for ovarian cancer and its underlying roles in immune regulation.

Exosome has been demonstrated to be secreted from cells and seized by targeted cells. Exosome could transmit signals and exert biological functions in cancer progression. Nevertheless, the underlying mechanisms of exosome in ovarian cancer (OC) have not been fully explored. In this study, we wanted to explore whether Fibroblast growth factor 9 (FGF9), as an exosome-associated gene, was importantly essential in OC progression and prognosis. Firstly, comprehensive bioinformatics platforms were applied to find that FGF9 expression was lower in OC tissues compared to normal ovarian tissues. Meanwhile, downregulated FGF9 displayed favorable prognostic values in OC patients. The gene enrichment of biological functions indicated that abnormally expressed FGF9 could be involved in the OC-related immune signatures, such as immunoinhibitors and chemokine receptors. Taken together, these findings could provide a novel insight into the significance of FGF9 in OC progress and supply a new destination of FGF9-related immunotherapy in clinical treatment.

CircTYW1 serves as a sponge for microRNA-380 in accelerating neurological recovery following spinal cord injury via regulating FGF9.

As one of the most severe kinds of neurological damage, spinal cord injury (SCI) contributes to persistent motor dysfunction and involves a large repertoire of gene alterations. The participation of circular RNAs (circRNAs) in neurological recovery following SCI needs to be clarified. In the current work, we attempted to assess the function of hsa_circRNA_0003962/circTYW1 and its underlying mechanism in SCI. By accessing the GEO repository, the expression of circTYW1, microRNA-380 (miR-380), and FGF9 in SCI and sham-operated rats was evaluated. PC12 cells after oxygen-glucose deprivation (OGD) treatment were prepared to mimic the SCI model. circTYW1 and FGF9 were poorly expressed, whereas miR-380 was highly expressed in the spinal cord tissues of SCI rats. circTYW1 promoted neurological recovery in SCI rats and inhibited apoptosis in spinal cord tissues. In PC12 cells exposed to OGD, circTYW1 suppressed PC12 cell apoptosis; however, miR-380 overexpression reversed the protective effect of circTYW1 on PC12 cells. Also, circTYW1 promoted FGF9 expression through competitively binding to miR-380, which activated the ERK1/2 signaling. In summary, our results demonstrated that declines in circTYW1 prevented SCI rats from neurological recovery by regulating the miR-380/FGF9/ERK1/2 axis, which might provide new understanding for SCI treatment.

Deletion of Fibroblast growth factor 9 globally and in skeletal muscle results in enlarged tuberosities at sites of deltoid tendon attachments.

BACKGROUND: The growth of most bony tuberosities, like the deltoid tuberosity (DT), rely on the transmission of muscle forces at the tendon-bone attachment during skeletal growth. Tuberosities distribute muscle forces and provide mechanical leverage at attachment sites for joint stability and mobility. The genetic factors that regulate tuberosity growth remain largely unknown. In mouse embryos with global deletion of fibroblast growth factor 9 (Fgf9), the DT size is notably enlarged. In this study, we explored the tissue-specific regulation of DT size using both global and targeted deletion of Fgf9. RESULTS: We showed that cell hypertrophy and mineralization dynamics of the DT, as well as transcriptional signatures from skeletal muscle but not bone, were influenced by the global loss of Fgf9. Loss of Fgf9 during embryonic growth led to increased chondrocyte hypertrophy and reduced cell proliferation at the DT attachment site. This endured hypertrophy and limited proliferation may explain the abnormal mineralization patterns and locally dysregulated expression of markers of endochondral development in Fgf9null attachments. We then showed that targeted deletion of Fgf9 in skeletal muscle leads to postnatal enlargement of the DT. CONCLUSION: Taken together, we discovered that Fgf9 may play an influential role in muscle-bone cross-talk during embryonic and postnatal development.

IL-8, MSPa, MIF, FGF-9, ANG-2 and AgRP collection were identified for the diagnosis of colorectal cancer based on the support vector machine model.

Colorectal cancer (CRC) is one of the most common cancer, and the early detection of CRC is essential to improve the survival rate of patients. To identify diagnostic markers for colorectal cancer (CRC) by screening differentially expressed proteins (DEPs) in CRC. The DEPs were initially obtained from 12 CRC samples and 12 healthy control samples, and verification analysis was performed in another 34 CRC samples and 34 normal controls. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment with DEPs was analyzed by the R package clusterProfiler (Version 3.2.11), and the DEP-associated protein-protein interaction (PPI) network was created from the STRING database. Additionally, Support Vector Machine (SVM) model prediction and survival analyses were conducted on the key DEPs. Preliminary screening and functional analysis showed that the DEPs mainly overrepresented in pathways such as cytokine-cytokine receptor interaction, chemokine signaling pathway, Rap1, Ras, and MAPK signaling pathways. The key DEPs, including AgRP, ANG-2, Dtk, EOT3, FGF-4, FGF-9, HCC-4, IL-16, IL-8, MIF, MSPa, TECK, TPO, TRAIL R3, and VEGF-D, were used to construct a custom chip. The drug-gene interaction network suggested that TPO was a key drug target. ROC curve showed the SVM diagnostic model with the DEPs IL-8, MSPa, MIF, FGF-9, ANG-2, and AgRP had better diagnostic performance with an AUC of 0.933. Survival analysis showed the expression of FGF9, TPO, TRAIL R3, Dtk, TECK and FGF4 were associated with prognosis. This study revealed the important serum proteins in the pathogenesis of CRC, which might serve as useful and noninvasive predictors for the diagnosis of CRC.

Deletion of FGF9 in GABAergic neurons causes epilepsy.

Fibroblast growth factor 9 (FGF9) has long been assumed to modulate multiple biological processes, yet very little is known about the impact of FGF9 on neurodevelopment. Herein, we found that loss of Fgf9 in olig1 progenitor cells induced epilepsy in mice, with pathological changes in the cortex. Then depleting Fgf9 in different neural populations revealed that epilepsy was associated with GABAergic neurons. Fgf9 CKO in GABAergic neuron (CKOVGAT) mice exhibited not only the most severe seizures, but also the most severe growth retardation and highest mortality. Fgf9 deletion in CKOVGAT mice caused neuronal apoptosis and decreased GABA expression, leading to a GABA/Glu imbalance and epilepsy. The adenylate cyclase/cyclic AMP and ERK signaling pathways were activated in this process. Recombinant FGF9 proteoliposomes could significantly decrease the number of seizures. Furthermore, the decrease of FGF9 was commonly observed in serum of epileptic patients, especially those with focal seizures. Thus, FGF9 plays essential roles in GABAergic neuron survival and epilepsy pathology, which could serve as a new target for the treatment of epilepsy.

Effect of lentivirus-mediated miR-182 targeting FGF9 on hallux valgus.

The pathogenesis of hallux valgus is not clearly understood. However, genetics research about hallux valgus is rare. Therefore, the present study aimed to explore the pathogeny of hallux valgus from the perspective of genetics. Human samples were collected from normal bone tissue and hallux valgus region bone tissue. The bone samples were studied using real time-PCR, western blot and immunohistochemical. Lentivirus-mediated miR-182 transfected osteoblasts and tested the expression of FGF9 mRNA with real time-PCR. To test alkaline phosphatase activity, number of calcium nodules and proliferation of osteoblast with enzymatic activity analysis, calcium nodules stained and MTT assay. We found that (1) FGF9 expressed in hallux valgus region bone tissue was significantly higher than normal bone tissue. (2) miR-182 expression levels in hallux valgus region bone tissue were notably lower than those of normal bone tissue. (3) miR-182 could negatively regulate the expression of FGF9 in osteoblasts. (4) FGF9 may enhance osteoblasts proliferation. We have demonstrated that miR-182 promotes the formation of bone by targeting FGF9, implicating an essential role of miR-182 in the etiology of hallux valgus. Moreover, miR-182 might potentially be a therapeutic target for hallux valgus treatment.

Expression of fibroblast growth factor 9 and its receptors in the dentate gyrus of hippocampus in poststroke depression rats.

Studies have found that fibroblast growth factor 9 (FGF9) might have a negative effect in the psychiatric diseases, such as depression or anxiety, but its potential role in the pathophysiology of poststroke depression (PSD) remains uncertain. Here, we set out to investigate the expression changes of FGF9 and its receptors in PSD rats. Middle cerebral artery occlusion (MCAO) combined with chronic unpredictable mild stress was used to establish the PSD rat model. Then, the rats were randomly divided into four groups: control (sham-operation), MCAO, PSD and treated (fluoxetine injection by intraperitoneal). Weight measurement, sucrose preference test, open-field test and forced swim test were performed to evaluate the behavioral changes, and then Western blot and real-time quantitative PCR were used to detect the expression level of FGF9, fibroblast growth factor receptor 1 (FGFR1) and receptor 3 (FGFR3) in the dentate gyrus of rat hippocampus. We found that FGF9 protein and mRNA expression increased significantly in the MCAO and PSD groups; FGFR3 protein and mRNA expression decreased significantly in the MCAO and PSD groups; FGFR1 protein and mRNA expression decreased significantly in the PSD group, but increased in the treated group. Furthermore, the changes mentioned above were reversed obviously by fluoxetine. These results indicated that upregulated FGF9 expression and downregulated FGFR1 and FGFR3 expression may be involved in the pathogenesis of PSD, and the FGF9/FGFR signaling pathway may be considered as an attractive target for further study.

A novel heterozygous variant in FGF9 associated with previously unreported features of multiple synostosis syndrome 3.

Human multiple synostoses syndrome 3 is an autosomal dominant disorder caused by pathogenic variants in FGF9. Only two variants have been described in FGF9 in humans so far, and one in mice. Here we report a novel missense variant c.566C > G, p.(Pro189Arg) in FGF9. Functional studies showed this variant impairs FGF9 homodimerization, but not FGFR3c binding. We also review the findings of cases reported previously and report on additional features not described previously.

Carnosic acid alleviates depression-like behaviors on chronic mild stressed mice via PPAR-γ-dependent regulation of ADPN/FGF9 pathway.

RATIONALE: The pathway of adiponectin (ADPN)/fibroblast growth factor 9 (FGF9) was recently thought as a key role in the development of depression. ADPN is crucially regulated by peroxisome proliferator-activated receptor-gamma (PPAR-γ). Natural material carnosic acid (CA) has been applied for therapeutics of mental disorders. OBJECTIVES: To evaluate the antidepressive effect of CA in stress-treated mice and define whether its effects is involved in the regulation of ADPN/FGF9 pathway. METHODS: In vivo study, the levels of ADPN and FGF9 in both serum and hippocampus tissues, the expressions of ADPN receptor 2 (AdipoR2) in hippocampus and PPAR-γ in abdominal adipose, as well as the pathological changes of hippocampus were determined in 28-day period of chronic unpredictable mild stress (CUMS)-induced depression model of male ICR (Institute of Cancer Research) mice or adipo-/- mice. In vitro study, the level of ADPN and the mRNA expressions of both ADPN and PPAR-γ were determined in mouse 3T3-L1 preadipocytes. RESULTS: In vivo study, treatment with CA (50 or 100 mg/kg per day) for 21 days markedly suppressed depressive-like behaviors, the elevating levels of FGF9 and decreasing levels of ADPN in both serum and hippocampus tissues, the downregulating protein and mRNA expressions of AdipoR2 in hippocampus and PPAR-γ in abdominal adipose, as well as the pathological injury of hippocampus induced by CUMS in male ICR mice. The antidepressive effects of CA were markedly attenuated in male CUMS-treated adipo-/- mice. In vitro study, incubation with CA (3-30 µmol/L) for 24 h could concentration-dependently upregulate the mRNA expressions of both PPAR-γ and ADPN as well as increase the level of ADPN. The experiments using PPAR-γ-specific inhibitor GW9662 and transient transfection with mutated PPAR-γ-binding site promotor constructs showed that the activation of PPAR-γ mediated CA-induced ADPN expression in adipocytes. CONCLUSIONS: CA could significantly improve stress-induced depressive disorder, which may be related to regulating the dysfunction of ADPN-FGF9 pathway via activating PPAR-γ in adipocytes.

Identification of the third FGF9 variant in a girl with multiple synostosis-comparison of the genotype:phenotype of FGF9 variants in humans and mice.

Multiple synostosis syndrome (SYNS) is a heterogeneous group of genetic disorders mainly characterized by multiple joint synostosis due to variants in either NOG, GDF5, FGF9 or GDF6. To date, only two FGF9 variants have been associated with SYNS, characterized with hand and feet joint synostosis and fusion of the elbow and vertebral lumbar joints. Craniosynostosis was also observed in one family. Here, we report the clinical and radiological description of a young girl with a third heterozygous FGF9 variant, NM_002010.2:c.427A>T;p.(Asn143Tyr), which interestingly, is located at the same amino acid as the well characterized spontaneous Eks mouse variant. We also compare the genotype: phenotypes observed between humans and mice with SYNS.