Aberrant Fibroblast Growth Factor Signaling Research Articles

Correction: Nucleolin loss of function leads to aberrant Fibroblast Growth Factor signaling and craniofacial anomalies

There were errors in Development (2022) 149, dev200349 (doi:10.1242/dev.200349).In the Materials and Methods section, the bmp2 primer sequences were listed incorrectly. The corrected text is shown below.Corrected:The following primers were used:…bmp2 forward, 5′-AGCTTCCACCATGATGAATCTACA-3′, and reverse, 5′-TCAGGTTGAAGAGGAACCGC-3′…Original:The following primers were used:…bmp2 forward, 5′-TCCATCACGAAGAAGCCGTGG-3′, and reverse, 5′-TGAGAAACTCGTCACTGGGGA-3′…The authors apologise for these errors and any inconvenience they may have caused. They do not impact the results or conclusions of this article.Both the online full-text and PDF versions of the paper have been corrected.

Nucleolin loss of function leads to aberrant Fibroblast Growth Factor signaling and craniofacial anomalies.

ABSTRACTRibosomal RNA (rRNA) transcription and ribosome biogenesis are global processes required for growth and proliferation of all cells, yet perturbation of these processes in vertebrates leads to tissue-specific defects termed ribosomopathies. Mutations in rRNA transcription and processing proteins often lead to craniofacial anomalies; however, the cellular and molecular reasons for these defects are poorly understood. Therefore, we examined the function of the most abundant nucleolar phosphoprotein, Nucleolin (Ncl), in vertebrate development. ncl mutant (ncl−/−) zebrafish present with craniofacial anomalies such as mandibulofacial hypoplasia. We observed that ncl−/− mutants exhibited decreased rRNA synthesis and p53-dependent apoptosis, consistent with a role in ribosome biogenesis. However, we found that Nucleolin also performs functions not associated with ribosome biogenesis. We discovered that the half-life of fgf8a mRNA was reduced in ncl−/− mutants, which perturbed Fgf signaling, resulting in misregulated Sox9a-mediated chondrogenesis and Runx2-mediated osteogenesis. Consistent with this model, exogenous FGF8 treatment significantly rescued the cranioskeletal phenotype in ncl−/− zebrafish, suggesting that Nucleolin regulates osteochondroprogenitor differentiation. Our work has therefore uncovered tissue-specific functions for Nucleolin in rRNA transcription and post-transcriptional regulation of growth factor signaling during embryonic craniofacial development.

Nanodiamonds as traps for fibroblast growth factors: Parameters influencing the interaction

Fibroblast growth factors (FGFs) deliver external cell communication signals, to regulate mammalian development, metabolism and homeostasis. Blocking the FGF interactions with their receptors at the cell membrane is one of the promising strategies for treatment of diseases related to dysregulated FGF signaling, such as cancer, metabolic syndromes, and developmental disorders. Recently, detonation nanodiamonds (NDs) with positive ζ-potential were identified as highly effective and selective FGF binders, sequestering FGF molecules and preventing their interaction with receptors under physiological conditions, thus potentially eliminating the effect of FGF overexpression. Here, we investigated the influence of ND origin (detonation vs. high-pressure high-temperature), surface modification, size and separation/purification steps on the sequestration ability and binding affinity of FGF2, a representative member of the FGF family. We measured FTIR and Raman spectra of the NDs, assessed their colloidal behavior and ζ-potential, and correlated their properties with FGF2 interaction levels. Using Western blot and ELISA, we quantified the strength of the interaction between detonation NDs and FGF2. All NDs with positive ζ-potential sequestered FGF2 at its physiologically relevant concentrations. Hydrogenated detonation NDs showed the highest binding capacity. Using Langmuir model, we estimated the apparent dissociation constant between FGF2 and detonation ND with positive ζ-potential to be in the nanomolar range in full fetal bovine serum. Because such tight interaction between a protein and a solid nanoparticle occurred in ∼105-fold molar excess of serum proteins, we believe that NDs can potentially be used in vivo as selective FGF traps to regulate disorders caused by aberrant FGF signaling.

Fibroblast growth factor receptor influences primary cilium length through an interaction with intestinal cell kinase

Vertebrate primary cilium is a Hedgehog signaling center but the extent of its involvement in other signaling systems is less well understood. This report delineates a mechanism by which fibroblast growth factor (FGF) controls primary cilia. Employing proteomic approaches to characterize proteins associated with the FGF-receptor, FGFR3, we identified the serine/threonine kinase intestinal cell kinase (ICK) as an FGFR interactor. ICK is involved in ciliogenesis and participates in control of ciliary length. FGF signaling partially abolished ICK's kinase activity, through FGFR-mediated ICK phosphorylation at conserved residue Tyr15, which interfered with optimal ATP binding. Activation of the FGF signaling pathway affected both primary cilia length and function in a manner consistent with cilia effects caused by inhibition of ICK activity. Moreover, knockdown and knockout of ICK rescued the FGF-mediated effect on cilia. We provide conclusive evidence that FGF signaling controls cilia via interaction with ICK.

Roles of FGF8 subfamily in embryogenesis and oral‑maxillofacial 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 oral‑maxillofacial diseases.

Mutation profiling of FGFR genes in solid tumors using comprehensive NGS panel.

e24241Background: Fibroblast growth factor (FGFR) signaling pathway is evolutionary conserved, and aberrant FGFR signaling is involved in the pathogenesis of cancer. A number of agents targeting th...

Green-Light-Induced Inactivation of Receptor Signaling Using Cobalamin-Binding Domains.

Optogenetics and photopharmacology provide spatiotemporally precise control over protein interactions and protein function in cells and animals. Optogenetic methods that are sensitive to green light and can be used to break protein complexes are not broadly available but would enable multichromatic experiments with previously inaccessible biological targets. Herein, we repurposed cobalamin (vitamin B12) binding domains of bacterial CarH transcription factors for green‐light‐induced receptor dissociation. In cultured cells, we observed oligomerization‐induced cell signaling for the fibroblast growth factor receptor 1 fused to cobalamin‐binding domains in the dark that was rapidly eliminated upon illumination. In zebrafish embryos expressing fusion receptors, green light endowed control over aberrant fibroblast growth factor signaling during development. Green‐light‐induced domain dissociation and light‐inactivated receptors will critically expand the optogenetic toolbox for control of biological processes.

Hyperactivated FRS2α-mediated signaling in prostate cancer cells promotes tumor angiogenesis and predicts poor clinical outcome of patients

Metastasis of tumors requires angiogenesis, which is comprised of multiple biological processes that are regulated by angiogenic factors. The fibroblast growth factor (FGF) is a potent angiogenic factor and aberrant FGF signaling is a common property of tumors. Yet, how the aberration in cancer cells contributes to angiogenesis in the tumor is not well understood. Most studies of its angiogenic signaling mechanisms have been in endothelial cells. FGF receptor substrate 2α (FRS2α) is an FGF receptor-associated protein required for activation of downstream signaling molecules that include those in the mitogen-activated protein and AKT kinase pathways. Herein, we demonstrated that overactivation and hyperactivity of FRS2α, as well as overexpression of cJUN and HIF1α, were positively correlated with vessel density and progression of human prostate cancer (PCa) toward malignancy. We also demonstrate that FGF upregulated the production of vascular endothelial growth factor A mainly by increasing expression of cJUN and HIF1α. This then promoted recruitment of endothelial cells and vessel formation for the tumor. Tumor angiogenesis in mouse PCa tissues was compromised by tissue-specific ablation of Frs2α in prostate epithelial cells. Depletion of Frs2α expression in human PCa cells and in a preclinical xenograft model, MDA PCa 118b, also significantly suppressed tumor angiogenesis accompanied with decreased tumor growth in the bone. The results underscore the angiogenic role of FRS2α-mediated signaling in tumor epithelial cells in angiogenesis. They provide a rationale for treating PCa with inhibitors of FGF signaling. They also demonstrate the potential of overexpressed FRS2α as a biomarker for PCa diagnosis, prognosis and response to therapies.

Fibroblast growth factor and canonical WNT/β-catenin signaling cooperate in suppression of chondrocyte differentiation in experimental models of FGFR signaling in cartilage

Aberrant fibroblast growth factor (FGF) signaling disturbs chondrocyte differentiation in skeletal dysplasia, but the mechanisms underlying this process remain unclear. Recently, FGF was found to activate canonical WNT/β-catenin pathway in chondrocytes via Erk MAP kinase-mediated phosphorylation of WNT co-receptor Lrp6. Here, we explore the cellular consequences of such a signaling interaction. WNT enhanced the FGF-mediated suppression of chondrocyte differentiation in mouse limb bud micromass and limb organ cultures, leading to inhibition of cartilage nodule formation in micromass cultures, and suppression of growth in cultured limbs. Simultaneous activation of the FGF and WNT/β-catenin pathways resulted in loss of chondrocyte extracellular matrix, expression of genes typical for mineralized tissues and alteration of cellular shape. WNT enhanced the FGF-mediated downregulation of chondrocyte proteoglycan and collagen extracellular matrix via inhibition of matrix synthesis and induction of proteinases involved in matrix degradation. Expression of genes regulating RhoA GTPase pathway was induced by FGF in cooperation with WNT, and inhibition of the RhoA signaling rescued the FGF/WNT-mediated changes in chondrocyte cellular shape. Our results suggest that aberrant FGF signaling cooperates with WNT/β-catenin in suppression of chondrocyte differentiation.

Fibroblast growth factor family as a potential target in the treatment of hepatocellular carcinoma.

Hepatocellular cancer (HCC) is currently the third leading cause of cancer death worldwide. The prognosis of patients diagnosed with late-stage disease is dismal due to high resistance to conventional systemic therapies. The introduction of sorafenib, despite its limited efficacy, as the standard systemic therapy for advanced HCC has paved a way for targeted molecular therapies for HCC. Fibroblast growth factor (FGF) signaling plays an important role in the developing embryo and the adult. The FGF signaling pathway is often hijacked by cancer cells, including HCC. Several alterations in FGF signaling correlate with poor outcome in HCC patients, suggesting that this family of signaling molecules plays an important role in the development of HCC. Multikinase inhibitors targeting FGF signaling are currently under investigation in clinical trials. This review discusses the current understanding of the biological and clinical implications of aberrant FGF signaling in the prognosis, diagnosis, and treatment of HCC.

Abstract 17730: Aberrant Endothelial FGF Signaling Due to Disruption of MicroRNAs 424/503 in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease characterized by the vascular remodeling of the pulmonary arterioles, including formation of plexiform and concentric lesions comprised of proliferative endothelial cells. We recently found that disruption of the G protein-coupled receptor signaling axis comprised of the ligand apelin and the receptor APJ leads to significant worsening of hypoxia induced pulmonary hypertension (PH) in mice, and found that the pathway is also perturbed in clinical PAH. To characterize novel downstream endothelial targets which may be utilized by apelin-APJ signaling to protect against the vascular remodeling processes in PAH, we carried out a microRNA (miRNA) array analysis of pulmonary artery endothelial cells (PAECs) subjected to knockdown of apelin, APJ, or both. We identified two miRNAs (miR-424 and miR-503) that are highly expressed in PAECs, but are significantly downregulated in the context of apelin/APJ knockdown. Remarkably, we found marked decrease in levels of miR-424 and miR-503 in the experimental monocrotaline (MCT) rat model of PH, as well as in PAECs isolated from a subset of patients with clinically diagnosed PAH. Our in vitro functional studies demonstrated that both miR-424 and miR-503 exert anti-proliferative, anti-angiogenic effects, via a mechanism that targets two key components of the fibroblast growth factor (FGF) signaling pathway, namely FGF2 and FGFR1. Consequently, we found marked increase in protein levels of FGF2 and FGFR1 in PAECs from PAH patients, as well as lungs of rats with MCT induced PH. Lastly, we found that restoration of miR-424/503 expression in the MCT induced model of PH by intranasal lentiviral delivery can significantly decrease FGF2 and FGFR1 expression and ameliorate the severity of the disease as demonstrated by decreased right ventricular systolic pressure (38 vs. 24.3 mmHg, p<0.001, n=5-8/group) and RV/LV+septum weight ratio (0.52 vs. 0.43, p<0.05). We conclude that miR-424/503 play a critical role in maintaining pulmonary vascular homeostasis, and that disruption of their expression serves a critical contribution to the aberrant endothelial proliferation that is a hallmark of PAH.

Immunolocalization of fibroblast growth factor receptors 1 and 2 in mouse palate development.

Recent evidence has implicated mutations of fibroblast growth factor receptors (FGF-R) in the pathogenesis of craniosynostotic syndromes. Cleft palate can be a component of such syndromes. The expression of FGF-R1 and FGF-R2 has been delineated in normally developing cranium, where they seem to regulate cellular differentiation and proliferation, respectively. The specific role of fibroblast growth factor signaling in mammalian palate development is unclear. The authors investigated the patterns of expression of FGF-R1 and FGF-R2 throughout mouse palatal development in the embryo. Time-dated CD-1 mouse heads (n = 135) were harvested at embryonic ages 12.5, 13.5, 14.5, 15.5, and 16.5 days (term gestation = 19.5 days), fixed in paraformaldehyde, embedded in paraffin, and sectioned. In addition, paired palatal shelves (n = 30) were isolated by means of microdissection from embryonic day--13.5 embryos, grown on Millipore filters in serum-free medium in vitro for 24, 48, 72, or 96 hours and processed for histological analysis. Immunohistochemical analysis for FGF-R1 and FGF-R2 was performed on the in vivo and in vitro specimens. FGF-R1 and FGF-R2 were found to be specifically expressed in the epithelium of the developing palatal shelves from the time of their outgrowth from the maxillary processes through completion of fusion in vivo and in vitro. Expression of both receptors was particularly strong during the phases of medial epithelial-medial epithelial contact between the individual shelves, through the formation of the medial epithelial seam, to the ultimate dissolution of the seam. Such a pattern of expression seems to implicate fibroblast growth factor signaling in the regulation of the critical phase of fusion of the bilateral shelves. The expression of both FGF-R1 and FGF-R2 in the lateral palatal mesenchyme, where such secondary structures as tooth primordia and bone begin to appear, also suggests a role for fibroblast growth factor signaling in the induction of ongoing differentiation and maturation of the palate after fusion. These data suggest that fibroblast growth factor signaling may play a role in the epithelial-mesenchymal interactions that dictate fusion and maturation of the developing palate. Furthermore, the data are consistent with the correlation of cleft palate formation with aberrant fibroblast growth factor signaling.