Publications by authors named "Moosa Mohammadi"

107 Publications

Rhenium N-heterocyclic carbene complexes block growth of aggressive cancers by inhibiting FGFR- and SRC-mediated signalling.

J Exp Clin Cancer Res 2020 Dec 7;39(1):276. Epub 2020 Dec 7.

Metabolic Signalling Group, School of Pharmacy & Biomedical Sciences, Curtin University, Perth, WA, 6102, Australia.

Background: Platinum-based anticancer drugs have been at the frontline of cancer therapy for the last 40 years, and are used in more than half of all treatments for different cancer types. However, they are not universally effective, and patients often suffer severe side effects because of their lack of cellular selectivity. There is therefore a compelling need to investigate the anticancer activity of alternative metal complexes. Here we describe the potential anticancer activity of rhenium-based complexes with preclinical efficacy in different types of solid malignancies.

Methods: Kinase profile assay of rhenium complexes. Toxicology studies using zebrafish. Analysis of the growth of pancreatic cancer cell line-derived xenografts generated in zebrafish and in mice upon exposure to rhenium compounds.

Results: We describe rhenium complexes which block cancer proliferation in vitro by inhibiting the signalling cascade induced by FGFR and Src. Initially, we tested the toxicity of rhenium complexes in vivo using a zebrafish model and identified one compound that displays anticancer activity with low toxicity even in the high micromolar range. Notably, the rhenium complex has anticancer activity in very aggressive cancers such as pancreatic ductal adenocarcinoma and neuroblastoma. We demonstrate the potential efficacy of this complex via a significant reduction in cancer growth in mouse xenografts.

Conclusions: Our findings provide a basis for the development of rhenium-based chemotherapy agents with enhanced selectivity and limited side effects compared to standard platinum-based drugs.
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http://dx.doi.org/10.1186/s13046-020-01777-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7720599PMC
December 2020

Curtailing FGF19's mitogenicity by suppressing its receptor dimerization ability.

Proc Natl Acad Sci U S A 2020 11 3;117(46):29025-29034. Epub 2020 Nov 3.

School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035 Zhejiang, China;

As a physiological regulator of bile acid homeostasis, FGF19 is also a potent insulin sensitizer capable of normalizing plasma glucose concentration, improving lipid profile, ameliorating fatty liver disease, and causing weight loss in both diabetic and diet-induced obesity mice. There is therefore a major interest in developing FGF19 as a therapeutic agent for treating type 2 diabetes and cholestatic liver disease. However, the known tumorigenic risk associated with prolonged FGF19 administration is a major hurdle in realizing its clinical potential. Here, we show that nonmitogenic FGF19 variants that retain the full beneficial glucose-lowering and bile acid regulatory activities of WT FGF19 (FGF19) can be engineered by diminishing FGF19's ability to induce dimerization of its cognate FGF receptors (FGFR). As proof of principle, we generated three such variants, each with a partial defect in binding affinity to FGFR (FGF19) and its coreceptors, i.e., βklotho (FGF19) or heparan sulfate (FGF19). Pharmacological assays in WT and mice confirmed that these variants incur a dramatic loss in mitogenic activity, yet are indistinguishable from FGF19 in eliciting glycemic control and regulating bile acid synthesis. This approach provides a robust framework for the development of safer and more efficacious FGF19 analogs.
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http://dx.doi.org/10.1073/pnas.2010984117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7682408PMC
November 2020

Activating Adenosine Monophosphate-Activated Protein Kinase Mediates Fibroblast Growth Factor 1 Protection From Nonalcoholic Fatty Liver Disease in Mice.

Hepatology 2021 Jun;73(6):2206-2222

Departments of Pediatrics, Pharmacology & Toxicology, Pediatric Research Institute, University of Louisville, Louisville, KY, USA.

Background And Aims: Fibroblast growth factor (FGF) 1 demonstrated protection against nonalcoholic fatty liver disease (NAFLD) in type 2 diabetic and obese mice by an uncertain mechanism. This study investigated the therapeutic activity and mechanism of a nonmitogenic FGF1 variant carrying 3 substitutions of heparin-binding sites (FGF1 ) against NAFLD.

Approach And Results: FGF1 administration was effective in 9-month-old diabetic mice carrying a homozygous mutation in the leptin receptor gene (db/db) with NAFLD; liver weight, lipid deposition, and inflammation declined and liver injury decreased. FGF1 reduced oxidative stress by stimulating nuclear translocation of nuclear erythroid 2 p45-related factor 2 (Nrf2) and elevation of antioxidant protein expression. FGF1 also inhibited activity and/or expression of lipogenic genes, coincident with phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and its substrates. Mechanistic studies on palmitate exposed hepatic cells demonstrated that NAFLD-like oxidative damage and lipid accumulation could be reversed by FGF1 . In palmitate-treated hepatic cells, small interfering RNA (siRNA) knockdown of Nrf2 abolished only FGF1 antioxidative actions but not improvement of lipid metabolism. In contrast, AMPK inhibition by pharmacological agent or siRNA abolished FGF1 benefits on both oxidative stress and lipid metabolism that were FGF receptor (FGFR) 4 dependent. Further support of these in vitro findings is that liver-specific AMPK knockout abolished therapeutic effects of FGF1 against high-fat/high-sucrose diet-induced hepatic steatosis. Moreover, FGF1 improved high-fat/high-cholesterol diet-induced steatohepatitis and fibrosis in apolipoprotein E knockout mice.

Conclusions: These findings indicate that FGF1 is effective for preventing and reversing liver steatosis and steatohepatitis and acts by activation of AMPK through hepatocyte FGFR4.
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http://dx.doi.org/10.1002/hep.31568DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8082952PMC
June 2021

Fibroblast growth factor signalling in osteoarthritis and cartilage repair.

Nat Rev Rheumatol 2020 10 17;16(10):547-564. Epub 2020 Aug 17.

Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.

Regulated fibroblast growth factor (FGF) signalling is a prerequisite for the correct development and homeostasis of articular cartilage, as evidenced by the fact that aberrant FGF signalling contributes to the maldevelopment of joints and to the onset and progression of osteoarthritis. Of the four FGF receptors (FGFRs 1-4), FGFR1 and FGFR3 are strongly implicated in osteoarthritis, and FGFR1 antagonists, as well as agonists of FGFR3, have shown therapeutic efficacy in mouse models of spontaneous and surgically induced osteoarthritis. FGF18, a high affinity ligand for FGFR3, is the only FGF-based drug currently in clinical trials for osteoarthritis. This Review covers the latest advances in our understanding of the molecular mechanisms that regulate FGF signalling during normal joint development and in the pathogenesis of osteoarthritis. Strategies for FGF signalling-based treatment of osteoarthritis and for cartilage repair in animal models and clinical trials are also introduced. An improved understanding of FGF signalling from a structural biology perspective, and of its roles in skeletal development and diseases, could unlock new avenues for discovery of modulators of FGF signalling that can slow or stop the progression of osteoarthritis.
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http://dx.doi.org/10.1038/s41584-020-0469-2DOI Listing
October 2020

C-FGF23 peptide alleviates hypoferremia during acute inflammation.

Haematologica 2021 02 1;106(2):391-403. Epub 2021 Feb 1.

NYU College of Dentistry and NYU School of Medicine, New York, USA.

Hypoferremia results as an acute phase response to infection and inflammation aiming to reduce iron availability to pathogens. Activation of toll-like receptors (TLRs), the key sensors of the innate immune system, induces hypoferremia mainly through the rise of the iron hormone hepcidin. Conversely, stimulation of erythropoiesis suppresses hepcidin expression via induction of the erythropoietin-responsive hormone erythroferrone. Iron deficiency stimulates transcription of the osteocyte-secreted protein FGF23. Here we hypothesized that induction of FGF23 in response to TLR4 activation is a potent contributor to hypoferremia and, thus, impairment of its activity may alleviate hypoferremia induced by lipopolysaccharide (LPS), a TLR 4 agonist. We used the C-terminal tail of FGF23 to impair endogenous full-length FGF23 signaling in wild-type mice, and investigated its impact on hypoferremia. Our data show that FGF23 is induced as early as pro-inflammatory cytokines in response to LPS, followed by upregulation of hepcidin and downregulation of erythropoietin (Epo) expression in addition to decreased serum iron and transferrin saturation. Further, LPS-induced hepatic and circulating hepcidin were significantly reduced by FGF23 signaling disruption. Accordingly, iron sequestration in liver and spleen caused by TLR4 activation was completely abrogated by FGF23 signaling inhibition, resulting in alleviation of serum iron and transferrin saturation deficit. Taken together, our studies highlight for the first time that inhibition of FGF23 signaling alleviates LPS-induced acute hypoferremia.
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http://dx.doi.org/10.3324/haematol.2019.237040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7849576PMC
February 2021

FGF6 and FGF9 regulate UCP1 expression independent of brown adipogenesis.

Nat Commun 2020 03 17;11(1):1421. Epub 2020 Mar 17.

Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA.

Uncoupling protein-1 (UCP1) plays a central role in energy dissipation in brown adipose tissue (BAT). Using high-throughput library screening of secreted peptides, we identify two fibroblast growth factors (FGF), FGF6 and FGF9, as potent inducers of UCP1 expression in adipocytes and preadipocytes. Surprisingly, this occurs through a mechanism independent of adipogenesis and involves FGF receptor-3 (FGFR3), prostaglandin-E2 and interaction between estrogen receptor-related alpha, flightless-1 (FLII) and leucine-rich-repeat-(in FLII)-interacting-protein-1 as a regulatory complex for UCP1 transcription. Physiologically, FGF6/9 expression in adipose is upregulated by exercise and cold in mice, and FGF9/FGFR3 expression in human neck fat is significantly associated with UCP1 expression. Loss of FGF9 impairs BAT thermogenesis. In vivo administration of FGF9 increases UCP1 expression and thermogenic capacity. Thus, FGF6 and FGF9 are adipokines that can regulate UCP1 through a transcriptional network that is dissociated from brown adipogenesis, and act to modulate systemic energy metabolism.
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http://dx.doi.org/10.1038/s41467-020-15055-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078224PMC
March 2020

Molecular basis for receptor tyrosine kinase A-loop tyrosine transphosphorylation.

Nat Chem Biol 2020 03 20;16(3):267-277. Epub 2020 Jan 20.

Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.

A long-standing mystery shrouds the mechanism by which catalytically repressed receptor tyrosine kinase domains accomplish transphosphorylation of activation loop (A-loop) tyrosines. Here we show that this reaction proceeds via an asymmetric complex that is thermodynamically disadvantaged because of an electrostatic repulsion between enzyme and substrate kinases. Under physiological conditions, the energetic gain resulting from ligand-induced dimerization of extracellular domains overcomes this opposing clash, stabilizing the A-loop-transphosphorylating dimer. A unique pathogenic fibroblast growth factor receptor gain-of-function mutation promotes formation of the complex responsible for phosphorylation of A-loop tyrosines by eliminating this repulsive force. We show that asymmetric complex formation induces a more phosphorylatable A-loop conformation in the substrate kinase, which in turn promotes the active state of the enzyme kinase. This explains how quantitative differences in the stability of ligand-induced extracellular dimerization promotes formation of the intracellular A-loop-transphosphorylating asymmetric complex to varying extents, thereby modulating intracellular kinase activity and signaling intensity.
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http://dx.doi.org/10.1038/s41589-019-0455-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040854PMC
March 2020

Paracrine-endocrine FGF chimeras as potent therapeutics for metabolic diseases.

EBioMedicine 2019 Oct 17;48:462-477. Epub 2019 Oct 17.

School of Pharmaceutical Sciences & Center for Structural Biology, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China. Electronic address:

Background: The development of a clinically useful fibroblast growth factor 21 (FGF21) hormone has been impeded by its inherent instability and weak FGF receptor (FGFR) binding affinity. There is an urgent need for innovative approaches to overcome these limitations.

Methods: We devised a structure-based chimerisation strategy in which we substituted the thermally labile and low receptor affinity core of FGF21 with an HS binding deficient endocrinised core derived from a stable and high receptor affinity paracrine FGF1 (FGF1). The thermal stability, receptor binding ability, heparan sulfate and βKlotho coreceptor dependency of the chimera were measured using a thermal shift assay, SPR, SEC-MALS and cell-based studies. The half-life, tissue distribution, glucose lowering activity and adipose tissue remodeling were analyzed in normal and diabetic mice and monkeys.

Findings: The melting temperature of the engineered chimera (FGF1-FGF21) increased by ∼22 °C relative to wild-type FGF21 (FGF21), and resulted in a ∼5-fold increase in half-life in vivo. The chimera also acquired an ability to bind the FGFR1c isoform - the principal receptor that mediates the metabolic actions of FGF21 - and consequently was dramatically more effective than FGF21 in correcting hyperglycemia and in ameliorating insulin resistance in db/db mice. Our chimeric FGF21 also exerted a significant beneficial effect on glycemic control in spontaneous diabetic cynomolgus monkeys.

Interpretation: Our study describes a structure-based chimerisation approach that effectively mitigates both the intrinsically weak receptor binding affinities and short half-lives of endocrine FGFs, and advance the development of the FGF21 hormone into a potentially useful drug for Type 2 diabetes.
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http://dx.doi.org/10.1016/j.ebiom.2019.09.052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6838362PMC
October 2019

A G protein-coupled, IP3/protein kinase C pathway controlling the synthesis of phosphaturic hormone FGF23.

JCI Insight 2019 09 5;4(17). Epub 2019 Sep 5.

Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.

Dysregulated actions of bone-derived phosphaturic hormone fibroblast growth factor 23 (FGF23) result in several inherited diseases, such as X-linked hypophosphatemia (XLH), and contribute substantially to the mortality in kidney failure. Mechanisms governing FGF23 production are poorly defined. We herein found that ablation of the Gq/11α-like, extralarge Gα subunit (XLαs), a product of GNAS, exhibits FGF23 deficiency and hyperphosphatemia in early postnatal mice (XLKO). FGF23 elevation in response to parathyroid hormone, a stimulator of FGF23 production via cAMP, was intact in XLKO mice, while skeletal levels of protein kinase C isoforms α and δ (PKCα and PKCδ) were diminished. XLαs ablation in osteocyte-like Ocy454 cells suppressed the levels of FGF23 mRNA, inositol 1,4,5-trisphosphate (IP3), and PKCα/PKCδ proteins. PKC activation in vivo via injecting phorbol myristate acetate (PMA) or by constitutively active Gqα-Q209L in osteocytes and osteoblasts promoted FGF23 production. Molecular studies showed that the PKC activation-induced FGF23 elevation was dependent on MAPK signaling. The baseline PKC activity was elevated in bones of Hyp mice, a model of XLH. XLαs ablation significantly, but modestly, reduced serum FGF23 and elevated serum phosphate in Hyp mice. These findings reveal a potentially hitherto-unknown mechanism of FGF23 synthesis involving a G protein-coupled IP3/PKC pathway, which may be targeted to fine-tune FGF23 levels.
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http://dx.doi.org/10.1172/jci.insight.125007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777913PMC
September 2019

A Conserved Allosteric Pathway in Tyrosine Kinase Regulation.

Structure 2019 08 13;27(8):1308-1315.e3. Epub 2019 Jun 13.

Department of Chemistry, New York University, New York, NY 10003, USA. Electronic address:

An autoinhibitory network of hydrogen bonds located at the kinase hinge (referred to as the "molecular brake") regulates the activity of several receptor tyrosine kinases. The mechanism whereby mutational disengagement of the brake allosterically activates the kinase in human disease is incompletely understood. We used a combination of NMR, bioinformatics, and molecular dynamics simulation to show that mutational disruption of the molecular brake triggers localized conformational perturbations that propagate to the active site. This entails changes in interactions of an isoleucine, one of three hydrophobic residues that lock the phenylalanine of the DFG motif in an inactive conformation. Structural analysis of tyrosine kinases provides evidence that this allosteric control mechanism is shared across the tyrosine kinase family. We also show that highly activating mutations at the brake diminish the enzyme's thermostability, thereby explaining why these mutations cause milder skeletal syndromes compared with less-activating mutations in the activation loop.
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http://dx.doi.org/10.1016/j.str.2019.05.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6687525PMC
August 2019

Structural Biology of the FGF7 Subfamily.

Front Genet 2019 12;10:102. Epub 2019 Feb 12.

Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, United States.

Mammalian fibroblast growth factor (FGF) signaling is intricately regulated via selective binding interactions between 18 FGF ligands and four FGF receptors (FGFR1-4), three of which (FGFR1-3) are expressed as either epithelial ("b") or mesenchymal ("c") splice isoforms. The FGF7 subfamily, consisting of FGF3, FGF7, FGF10, and FGF22, is unique among FGFs in that its members are secreted exclusively by the mesenchyme, and specifically activate the "b" isoforms of FGFR1 (FGFR1b) and FGFR2 (FGFR2b) present in the overlying epithelium. This unidirectional mesenchyme-to-epithelium signaling contributes to the development of essentially all organs, glands, and limbs. Structural analysis has shown that members of the FGF7 subfamily achieve their restricted specificity for FGFR1b/FGFR2b by engaging in specific contacts with two alternatively spliced loop regions in the immunoglobulin-like domain 3 (D3) of these receptors. Weak basal receptor-binding affinity further constrains the FGF7 subfamily's specificity for FGFR1b/2b. In this review, we elaborate on the structural determinants of FGF7 subfamily receptor-binding specificity, and discuss how affinity differences among the four members for the heparin sulfate (HS) co-receptor contribute to their disparate biological activities.
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http://dx.doi.org/10.3389/fgene.2019.00102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6379346PMC
February 2019

Fibroblast Growth Factor Binding Protein 3 (FGFBP3) impacts carbohydrate and lipid metabolism.

Sci Rep 2018 10 29;8(1):15973. Epub 2018 Oct 29.

Lombardi Comprehensive Cancer Center, Department of Oncology, Georgetown University, School of Medicine, Washington, DC, 20007, USA.

Secreted FGF binding proteins (FGFBP) mobilize locally-acting paracrine FGFs from their extracellular storage. Here, we report that FGFBP3 (BP3) modulates fat and glucose metabolism in mouse models of metabolic syndrome. BP3 knockout mice exhibited altered lipid metabolism pathways with reduced hepatic and serum triglycerides. In obese mice the expression of exogenous BP3 reduced hyperglycemia, hepatosteatosis and weight gain, blunted de novo lipogenesis in liver and adipose tissues, increased circulating adiponectin and decreased NEFA. The BP3 protein interacts with endocrine FGFs through its C-terminus and thus enhances their signaling. We propose that BP3 may constitute a new therapeutic to reverse the pathology associated with metabolic syndrome that includes nonalcoholic fatty liver disease and type 2 diabetes mellitus.
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http://dx.doi.org/10.1038/s41598-018-34238-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6206164PMC
October 2018

A threshold model for receptor tyrosine kinase signaling specificity and cell fate determination.

F1000Res 2018 21;7. Epub 2018 Jun 21.

Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.

Upon ligand engagement, the single-pass transmembrane receptor tyrosine kinases (RTKs) dimerize to transmit qualitatively and quantitatively different intracellular signals that alter the transcriptional landscape and thereby determine the cellular response. The molecular mechanisms underlying these fundamental events are not well understood. Considering recent insights into the structural biology of fibroblast growth factor signaling, we propose a threshold model for RTK signaling specificity in which quantitative differences in the strength/longevity of ligand-induced receptor dimers on the cell surface lead to quantitative differences in the phosphorylation of activation loop (A-loop) tyrosines as well as qualitative differences in the phosphorylation of tyrosines mediating substrate recruitment. In this model, quantitative differences on A-loop tyrosine phosphorylation result in gradations in kinase activation, leading to the generation of intracellular signals of varying amplitude/duration. In contrast, qualitative differences in the pattern of tyrosine phosphorylation on the receptor result in the recruitment/activation of distinct substrates/intracellular pathways. Commensurate with both the dynamics of the intracellular signal and the types of intracellular pathways activated, unique transcriptional signatures are established. Our model provides a framework for engineering clinically useful ligands that can tune receptor dimerization stability so as to bias the cellular transcriptome to achieve a desired cellular output.
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http://dx.doi.org/10.12688/f1000research.14143.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6013765PMC
June 2018

Inhibition of fibroblast growth factor 23 (FGF23) signaling rescues renal anemia.

FASEB J 2018 07 26;32(7):3752-3764. Epub 2018 Feb 26.

Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, New York, USA.

Severe anemia and iron deficiency are common complications in chronic kidney disease. The cause of renal anemia is multifactorial and includes decreased erythropoietin (Epo) production, iron deficiency, and inflammation, and it is currently treated with injections of synthetic Epo. However, the use of recombinant Epo has several adverse effects. We previously reported that high fibroblast growth factor 23 (FGF23) levels in mice are associated with decreased red blood cell production, whereas genetic inactivation of Fgf23 results in expansion of the erythroid lineage. The present study is the first to show that high FGF23 levels in a mouse model of renal failure contribute to renal anemia, and inhibiting FGF23 signaling stimulates erythropoiesis and abolishes anemia and iron deficiency. Moreover, we show that inhibition of FGF23 signaling significantly decreases erythroid cell apoptosis and influences the commitment of hematopoietic stem cells toward the erythroid linage. Furthermore, we show that blocking FGF23 signaling attenuates inflammation, resulting in increased serum iron and ferritin levels. Our data clearly demonstrate that elevated FGF23 is a causative factor in the development of renal anemia and iron deficiency, and importantly, blocking FGF23 signaling represents a novel approach to stimulate erythropoiesis and possibly improve survival for millions of chronic kidney disease patients worldwide.-Agoro, R., Montagna, A., Goetz, R., Aligbe, O., Singh, G., Coe, L. M., Mohammadi, M., Rivella, S., Sitara, D. Inhibition of fibroblast growth factor 23 (FGF23) signaling rescues renal anemia.
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http://dx.doi.org/10.1096/fj.201700667RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5998980PMC
July 2018

α-Klotho is a non-enzymatic molecular scaffold for FGF23 hormone signalling.

Nature 2018 01 17;553(7689):461-466. Epub 2018 Jan 17.

Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA.

The ageing suppressor α-klotho binds to the fibroblast growth factor receptor (FGFR). This commits FGFR to respond to FGF23, a key hormone in the regulation of mineral ion and vitamin D homeostasis. The role and mechanism of this co-receptor are unknown. Here we present the atomic structure of a 1:1:1 ternary complex that consists of the shed extracellular domain of α-klotho, the FGFR1c ligand-binding domain, and FGF23. In this complex, α-klotho simultaneously tethers FGFR1c by its D3 domain and FGF23 by its C-terminal tail, thus implementing FGF23-FGFR1c proximity and conferring stability. Dimerization of the stabilized ternary complexes and receptor activation remain dependent on the binding of heparan sulfate, a mandatory cofactor of paracrine FGF signalling. The structure of α-klotho is incompatible with its purported glycosidase activity. Thus, shed α-klotho functions as an on-demand non-enzymatic scaffold protein that promotes FGF23 signalling.
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http://dx.doi.org/10.1038/nature25451DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6007875PMC
January 2018

A novel fibroblast growth factor-1 ligand with reduced heparin binding protects the heart against ischemia-reperfusion injury in the presence of heparin co-administration.

Cardiovasc Res 2017 Nov;113(13):1585-1602

Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.

Aims: Fibroblast growth factor 1 (FGF1), a heparin/heparan sulfate-binding growth factor, is a potent cardioprotective agent against myocardial infarction (MI). The impact of heparin, the standard of care for MI patients entering the emergency room, on cardioprotective effects of FGF1 is unknown, however.

Methods And Results: To address this, a rat model of MI was employed to compare cardioprotective potentials (lower infarct size and improve post-ischemic function) of native FGF1 and an engineered FGF1 (FGF1ΔHBS) with reduced heparin-binding affinity when given at the onset of reperfusion in the absence or presence of heparin. FGF1 and FGF1ΔHBS did not alter heparin's anticoagulant properties. Treatment with heparin alone or native FGF1 significantly reduced infarct size compared to saline (P < 0.05). Surprisingly, treatment with FGF1ΔHBS markedly lowered infarct size compared to FGF1 (P < 0.05). Both native and modified FGF1 restored contractile and relaxation function (P < 0.05 versus saline or heparin). Furthermore, FGF1ΔHBS had greater improvement in cardiac function compared to FGF1 (P < 0.05). Heparin negatively impacted the cardioprotective effects (infarct size, post-ischemic recovery of function) of FGF1 (P < 0.05) but not of FGF1ΔHBS. Heparin also reduced the biodistribution of FGF1, but not FGF1ΔHBS, to the left ventricle. FGF1 and FGF1ΔHBS bound and triggered FGFR1-induced downstream activation of ERK1/2 (P < 0.05); yet, heparin co-treatment decreased FGF1-produced ERK1/2 activation, but not that activated by FGF1ΔHBS.

Conclusion: These findings demonstrate that modification of the heparin-binding region of FGF1 significantly improves the cardioprotective efficacy, even in the presence of heparin, identifying a novel FGF ligand available for therapeutic use in ischemic heart disease.
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http://dx.doi.org/10.1093/cvr/cvx165DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5852627PMC
November 2017

Uncoupling the Mitogenic and Metabolic Functions of FGF1 by Tuning FGF1-FGF Receptor Dimer Stability.

Cell Rep 2017 08;20(7):1717-1728

Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA. Electronic address:

The recent discovery of metabolic roles for fibroblast growth factor 1 (FGF1) in glucose homeostasis has expanded the functions of this classically known mitogen. To dissect the molecular basis for this functional pleiotropy, we engineered an FGF1 partial agonist carrying triple mutations (FGF1) that diminished its ability to induce heparan sulfate (HS)-assisted FGF receptor (FGFR) dimerization and activation. FGF1 exhibited a severely reduced proliferative potential, while preserving the full metabolic activity of wild-type FGF1 in vitro and in vivo. Hence, suboptimal FGFR activation by a weak FGF1-FGFR dimer is sufficient to evoke a metabolic response, whereas full FGFR activation by stable and sustained dimerization is required to elicit a mitogenic response. In addition to providing a physical basis for the diverse activities of FGF1, our findings will impact ongoing drug discoveries targeting FGF1 and related FGFs for the treatment of a variety of human diseases.
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http://dx.doi.org/10.1016/j.celrep.2017.06.063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821125PMC
August 2017

Regulation of Receptor Binding Specificity of FGF9 by an Autoinhibitory Homodimerization.

Structure 2017 09 27;25(9):1325-1336.e3. Epub 2017 Jul 27.

Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA. Electronic address:

The epithelial fibroblast growth factor 9 (FGF9) subfamily specifically binds and activates the mesenchymal "c" splice isoform of FGF receptors 1-3 (FGFR1-3) to regulate organogenesis and tissue homeostasis. The unique N and C termini of FGF9 subfamily ligands mediate a reversible homodimerization that occludes major receptor binding sites within the ligand core region. Here we provide compelling X-ray crystallographic, biophysical, and biochemical data showing that homodimerization controls receptor binding specificity of the FGF9 subfamily by keeping the concentration of active FGF9 monomers at a level, which is sufficient for a normal FGFR "c" isoform binding/signaling, but is insufficient for an illegitimate FGFR "b" isoform binding/signaling. We show that deletion of the N terminus or alanine substitutions in the C terminus of FGF9 skews the delicate ligand equilibrium toward active FGF9 monomers causing off-target binding and activation of FGFR b isoforms. Our study is the first to implicate ligand homodimerization in the regulation of ligand-receptor specificity.
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http://dx.doi.org/10.1016/j.str.2017.06.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5587394PMC
September 2017

, encoding β-Klotho, is mutated in patients with congenital hypogonadotropic hypogonadism.

EMBO Mol Med 2017 10;9(10):1379-1397

Service of Endocrinology, Diabetology & Metabolism, Lausanne University Hospital, Lausanne, Switzerland

Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic form of isolated gonadotropin-releasing hormone (GnRH) deficiency caused by mutations in > 30 genes. Fibroblast growth factor receptor 1 () is the most frequently mutated gene in CHH and is implicated in GnRH neuron development and maintenance. We note that a CHH mutation (p.L342S) decreases signaling of the metabolic regulator FGF21 by impairing the association of FGFR1 with β-Klotho (KLB), the obligate co-receptor for FGF21. We thus hypothesized that the metabolic FGF21/KLB/FGFR1 pathway is involved in CHH Genetic screening of 334 CHH patients identified seven heterozygous loss-of-function mutations in 13 patients (4%). Most patients with mutations (9/13) exhibited metabolic defects. In mice, lack of led to delayed puberty, altered estrous cyclicity, and subfertility due to a hypothalamic defect associated with inability of GnRH neurons to release GnRH in response to FGF21. Peripheral FGF21 administration could indeed reach GnRH neurons through circumventricular organs in the hypothalamus. We conclude that FGF21/KLB/FGFR1 signaling plays an essential role in GnRH biology, potentially linking metabolism with reproduction.
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http://dx.doi.org/10.15252/emmm.201607376DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5623842PMC
October 2017

Fibroblast growth factor 1 ameliorates diabetic nephropathy by an anti-inflammatory mechanism.

Kidney Int 2018 01 24;93(1):95-109. Epub 2017 Jul 24.

School of Pharmaceutical Sciences and Center for Structural Biology, Wenzhou Medical University, Wenzhou, Zhejiang, China. Electronic address:

Inflammation plays a central role in the etiology of diabetic nephropathy, a global health issue. We observed a significant reduction in the renal expression of fibroblast growth factor 1, a known mitogen and insulin sensitizer, in patients with diabetic nephropathy and in mouse models implying that fibroblast growth factor 1 possesses beneficial anti-inflammatory and renoprotective activities in vivo. To test this possibility, we investigated the effects of chronic intraperitoneal administration of fibroblast growth factor 1 into both the streptozotocin-induced type 1 diabetes and db/db type 2 diabetes models. Indeed, recombinant fibroblast growth factor 1 significantly suppressed renal inflammation (i.e., cytokines, macrophage infiltration), glomerular and tubular damage, and renal dysfunction in both type 1 and type 2 diabetes mice. Fibroblast growth factor 1 was able to correct the elevated blood glucose levels in type 2 but not in type 1 diabetic mice, suggesting that the anti-inflammatory effect of fibroblast growth factor 1 was independent of its glucose-lowering activity. The mechanistic study demonstrated that fibroblast growth factor 1-mediated inhibition of the renal inflammation in vivo was accompanied by attenuation of the nuclear factor κB and c-Jun N-terminal kinase signaling pathways, further validated in vitro using cultured glomerular mesangial cells and podocytes. Thus, fibroblast growth factor 1 holds great promise for developing new treatments for diabetic nephropathy through countering inflammatory signaling cascades in injured renal tissue.
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http://dx.doi.org/10.1016/j.kint.2017.05.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5818994PMC
January 2018

Therapeutic Effects of FGF23 c-tail Fc in a Murine Preclinical Model of X-Linked Hypophosphatemia Via the Selective Modulation of Phosphate Reabsorption.

J Bone Miner Res 2017 Oct 25;32(10):2062-2073. Epub 2017 Aug 25.

Center for Therapeutic Innovation, Pfizer, New York, NY, USA.

Fibroblast growth factor 23 (FGF23) is the causative factor of X-linked hypophosphatemia (XLH), a genetic disorder effecting 1:20,000 that is characterized by excessive phosphate excretion, elevated FGF23 levels and a rickets/osteomalacia phenotype. FGF23 inhibits phosphate reabsorption and suppresses 1α,25-dihydroxyvitamin D (1,25D) biosynthesis, analytes that differentially contribute to bone integrity and deleterious soft-tissue mineralization. As inhibition of ligand broadly modulates downstream targets, balancing efficacy and unwanted toxicity is difficult when targeting the FGF23 pathway. We demonstrate that a FGF23 c-tail-Fc fusion molecule selectively modulates the phosphate pathway in vivo by competitive antagonism of FGF23 binding to the FGFR/α klotho receptor complex. Repeated injection of FGF23 c-tail Fc in Hyp mice, a preclinical model of XLH, increases cell surface abundance of kidney NaPi transporters, normalizes phosphate excretion, and significantly improves bone architecture in the absence of soft-tissue mineralization. Repeated injection does not modulate either 1,25D or calcium in a physiologically relevant manner in either a wild-type or disease setting. These data suggest that bone integrity can be improved in models of XLH via the exclusive modulation of phosphate. We posit that the selective modulation of the phosphate pathway will increase the window between efficacy and safety risks, allowing increased efficacy to be achieved in the treatment of this chronic disease. © 2017 American Society for Bone and Mineral Research.
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http://dx.doi.org/10.1002/jbmr.3197DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5816679PMC
October 2017

β-Klotho deficiency protects against obesity through a crosstalk between liver, microbiota, and brown adipose tissue.

JCI Insight 2017 Apr 20;2(8). Epub 2017 Apr 20.

Service of Endocrinology, Diabetology and Metabolism, Lausanne University Hospital; Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.

β-Klotho (encoded by Klb) is the obligate coreceptor mediating FGF21 and FGF15/19 signaling. Klb-/- mice are refractory to beneficial action of pharmacological FGF21 treatment including stimulation of glucose utilization and thermogenesis. Here, we investigated the energy homeostasis in Klb-/- mice on high-fat diet in order to better understand the consequences of abrogating both endogenous FGF15/19 and FGF21 signaling during caloric overload. Surprisingly, Klb-/- mice are resistant to diet-induced obesity (DIO) owing to enhanced energy expenditure and BAT activity. Klb-/- mice exhibited not only an increase but also a shift in bile acid (BA) composition featured by activation of the classical (neutral) BA synthesis pathway at the expense of the alternative (acidic) pathway. High hepatic production of cholic acid (CA) results in a large excess of microbiota-derived deoxycholic acid (DCA). DCA is specifically responsible for activating the TGR5 receptor that stimulates BAT thermogenic activity. In fact, combined gene deletion of Klb and Tgr5 or antibiotic treatment abrogating bacterial conversion of CA into DCA both abolish DIO resistance in Klb-/- mice. These results suggested that DIO resistance in Klb-/- mice is caused by high levels of DCA, signaling through the TGR5 receptor. These data also demonstrated that gut microbiota can regulate host thermogenesis via conversion of primary into secondary BA. Pharmacologic or nutritional approaches to selectively modulate BA composition may be a promising target for treating metabolic disorders.
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http://dx.doi.org/10.1172/jci.insight.91809DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5396514PMC
April 2017

Elucidation of a four-site allosteric network in fibroblast growth factor receptor tyrosine kinases.

Elife 2017 02 6;6. Epub 2017 Feb 6.

Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, United States.

Receptor tyrosine kinase (RTK) signaling is tightly regulated by protein allostery within the intracellular tyrosine kinase domains. Yet the molecular determinants of allosteric connectivity in tyrosine kinase domain are incompletely understood. By means of structural (X-ray and NMR) and functional characterization of pathogenic gain-of-function mutations affecting the FGF receptor (FGFR) tyrosine kinase domain, we elucidated a long-distance allosteric network composed of four interconnected sites termed the 'molecular brake', 'DFG latch', 'A-loop plug', and 'αC tether'. The first three sites repress the kinase from adopting an active conformation, whereas the αC tether promotes the active conformation. The skewed design of this four-site allosteric network imposes tight autoinhibition and accounts for the incomplete mimicry of the activated conformation by pathogenic mutations targeting a single site. Based on the structural similarity shared among RTKs, we propose that this allosteric model for FGFR kinases is applicable to other RTKs.
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http://dx.doi.org/10.7554/eLife.21137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5293489PMC
February 2017

Fibroblast growth factor 21 deficiency exacerbates chronic alcohol-induced hepatic steatosis and injury.

Sci Rep 2016 08 8;6:31026. Epub 2016 Aug 8.

School of Pharmacy and First Affiliate Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China.

Fibroblast growth factor 21 (FGF21) is a hepatokine that regulates glucose and lipid metabolism in the liver. We sought to determine the role of FGF21 in hepatic steatosis in mice exposed to chronic alcohol treatment and to discern underlying mechanisms. Male FGF21 knockout (FGF21 KO) and control (WT) mice were divided into groups that were fed either the Lieber DeCarli diet containing 5% alcohol or an isocaloric (control) diet for 4 weeks. One group of WT mice exposed to alcohol received recombinant human FGF21 (rhFGF21) in the last 5 days. Liver steatosis and inflammation were assessed. Primary mouse hepatocytes and AML-12 cells were incubated with metformin or rhFGF21. Hepatic genes and the products involved in in situ lipogenesis and fatty acid β-oxidation were analyzed. Alcohol exposure increased circulating levels and hepatic expression of FGF21. FGF21 depletion exacerbated alcohol-induced hepatic steatosis and liver injury, which was associated with increased activation of genes involved in lipogenesis mediated by SREBP1c and decreased expression of genes involved in fatty acid β-oxidation mediated by PGC1α. rhFGF21 administration reduced alcohol-induced hepatic steatosis and inflammation in WT mice. These results reveal that alcohol-induced FGF21 expression is a hepatic adaptive response to lipid dysregulation. Targeting FGF21 signaling could be a novel treatment approach for alcoholic steatohepatitis.
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http://dx.doi.org/10.1038/srep31026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4976373PMC
August 2016

Fibulin-1 Binds to Fibroblast Growth Factor 8 with High Affinity: EFFECTS ON EMBRYO SURVIVAL.

J Biol Chem 2016 09 8;291(36):18730-9. Epub 2016 Jul 8.

From the Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425 and

Fibulin-1 (FBLN1) is a member of a growing family of extracellular matrix glycoproteins that includes eight members and is involved in cellular functions such as adhesion, migration, and differentiation. FBLN1 has also been implicated in embryonic heart and valve development and in the formation of neural crest-derived structures, including aortic arch, thymus, and cranial nerves. Fibroblast growth factor 8 (FGF8) is a member of a large family of growth factors, and its functions include neural crest cell (NCC) maintenance, specifically NCC migration as well as patterning of structures formed from NCC such as outflow tract and cranial nerves. In this report, we sought to investigate whether FBLN1 and FGF8 have cooperative roles in vivo given their influence on the development of the same NCC-derived structures. Surface plasmon resonance binding data showed that FBLN1 binds tightly to FGF8 and prevents its enzymatic degradation by ADAM17. Moreover, overexpression of FBLN1 up-regulates FGF8 gene expression, and down-regulation of FBLN1 by siRNA inhibits FGF8 expression. The generation of a double mutant Fbln1 and Fgf8 mice (Fbln1(-/-) and Fgf8(-/-)) showed that haplo-insufficiency (Fbln1(+/-) and Fgf8(+/-)) resulted in increased embryonic mortality compared with single heterozygote crosses. The mortality of the FGF8/Fbln1 double heterozygote embryos occurred between 14.5 and 16.5 days post-coitus. In conclusion, FBLN1/FGF8 interaction plays a role in survival of vertebrate embryos, and reduced levels of both proteins resulted in added mortality in utero The FBLN1/FGF8 interaction may also be involved in the survival of neural crest cell population during development.
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http://dx.doi.org/10.1074/jbc.M115.702761DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009248PMC
September 2016

Two FGF Receptor Kinase Molecules Act in Concert to Recruit and Transphosphorylate Phospholipase Cγ.

Mol Cell 2016 Jan 10;61(1):98-110. Epub 2015 Dec 10.

Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA. Electronic address:

The molecular basis by which receptor tyrosine kinases (RTKs) recruit and phosphorylate Src Homology 2 (SH2) domain-containing substrates has remained elusive. We used X-ray crystallography, NMR spectroscopy, and cell-based assays to demonstrate that recruitment and phosphorylation of Phospholipase Cγ (PLCγ), a prototypical SH2 containing substrate, by FGF receptors (FGFR) entails formation of an allosteric 2:1 FGFR-PLCγ complex. We show that the engagement of pTyr-binding pocket of the cSH2 domain of PLCγ by the phosphorylated tail of an FGFR kinase induces a conformational change at the region past the cSH2 core domain encompassing Tyr-771 and Tyr-783 to facilitate the binding/phosphorylation of these tyrosines by another FGFR kinase in trans. Our data overturn the current paradigm that recruitment and phosphorylation of substrates are carried out by the same RTK monomer in cis and disclose an obligatory role for receptor dimerization in substrate phosphorylation in addition to its canonical role in kinase activation.
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http://dx.doi.org/10.1016/j.molcel.2015.11.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4838190PMC
January 2016

FGF21 mediates alcohol-induced adipose tissue lipolysis by activation of systemic release of catecholamine in mice.

J Lipid Res 2015 Aug 19;56(8):1481-91. Epub 2015 Jun 19.

Departments of Medicine University of Louisville School of Medicine, Louisville, KY Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China.

Alcohol consumption leads to adipose tissue lipoatrophy and mobilization of FFAs, which contributes to hepatic fat accumulation in alcoholic liver disease. This study aimed to investigate the role of fibroblast growth factor (FGF)21, a metabolic regulator, in the regulation of chronic-binge alcohol-induced adipose tissue lipolysis. FGF21 KO mice were subjected to chronic-binge alcohol exposure, and epididymal white adipose tissue lipolysis and liver steatosis were investigated. Alcohol exposure caused adipose intracellular cAMP elevation and activation of lipolytic enzymes, leading to FFA mobilization in both WT and FGF21 KO mice. However, alcohol-induced systemic elevation of catecholamine, which is known to be a major player in adipose lipolysis by binding to the β-adrenergic receptor, was markedly inhibited in KO mice. Supplementation with recombinant human FGF21 to alcohol-exposed FGF21 KO mice resulted in an increase in fat loss in parallel with an increase of circulating norepinephrine concentration. Furthermore, alcohol consumption-induced fatty liver was blunted in the KO mice, indicating an inhibition of fatty acid reverse transport from adipose to the liver in the KO mice. Taken together, our studies demonstrate that FGF21 KO mice are protected from alcohol-induced adipose tissue excess-lipolysis through a mechanism involving systemic catecholamine release.
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http://dx.doi.org/10.1194/jlr.M058610DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4513989PMC
August 2015

Congenital hypogonadotropic hypogonadism with split hand/foot malformation: a clinical entity with a high frequency of FGFR1 mutations.

Genet Med 2015 Aug 13;17(8):651-9. Epub 2014 Nov 13.

1] Harvard Reproductive Endocrine Sciences Center and the Reproductive Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA [2] Department of Endocrinology, Diabetology and Metabolism, Lausanne University Hospital (CHUV), Lausanne, Switzerland [3] Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.

Purpose: Congenital hypogonadotropic hypogonadism (CHH) and split hand/foot malformation (SHFM) are two rare genetic conditions. Here we report a clinical entity comprising the two.

Methods: We identified patients with CHH and SHFM through international collaboration. Probands and available family members underwent phenotyping and screening for FGFR1 mutations. The impact of identified mutations was assessed by sequence- and structure-based predictions and/or functional assays.

Results: We identified eight probands with CHH with (n = 3; Kallmann syndrome) or without anosmia (n = 5) and SHFM, seven of whom (88%) harbor FGFR1 mutations. Of these seven, one individual is homozygous for p.V429E and six individuals are heterozygous for p.G348R, p.G485R, p.Q594*, p.E670A, p.V688L, or p.L712P. All mutations were predicted by in silico analysis to cause loss of function. Probands with FGFR1 mutations have severe gonadotropin-releasing hormone deficiency (absent puberty and/or cryptorchidism and/or micropenis). SHFM in both hands and feet was observed only in the patient with the homozygous p.V429E mutation; V429 maps to the fibroblast growth factor receptor substrate 2α binding domain of FGFR1, and functional studies of the p.V429E mutation demonstrated that it decreased recruitment and phosphorylation of fibroblast growth factor receptor substrate 2α to FGFR1, thereby resulting in reduced mitogen-activated protein kinase signaling.

Conclusion: FGFR1 should be prioritized for genetic testing in patients with CHH and SHFM because the likelihood of a mutation increases from 10% in the general CHH population to 88% in these patients.
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http://dx.doi.org/10.1038/gim.2014.166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4430466PMC
August 2015

Development of covalent inhibitors that can overcome resistance to first-generation FGFR kinase inhibitors.

Proc Natl Acad Sci U S A 2014 Nov 27;111(45):E4869-77. Epub 2014 Oct 27.

Departments of Biological Chemistry and Molecular Pharmacology, Departments of Cancer Biology and

The human FGF receptors (FGFRs) play critical roles in various human cancers, and several FGFR inhibitors are currently under clinical investigation. Resistance usually results from selection for mutant kinases that are impervious to the action of the drug or from up-regulation of compensatory signaling pathways. Preclinical studies have demonstrated that resistance to FGFR inhibitors can be acquired through mutations in the FGFR gatekeeper residue, as clinically observed for FGFR4 in embryonal rhabdomyosarcoma and neuroendocrine breast carcinomas. Here we report on the use of a structure-based drug design to develop two selective, next-generation covalent FGFR inhibitors, the FGFR irreversible inhibitors 2 (FIIN-2) and 3 (FIIN-3). To our knowledge, FIIN-2 and FIIN-3 are the first inhibitors that can potently inhibit the proliferation of cells dependent upon the gatekeeper mutants of FGFR1 or FGFR2, which confer resistance to first-generation clinical FGFR inhibitors such as NVP-BGJ398 and AZD4547. Because of the conformational flexibility of the reactive acrylamide substituent, FIIN-3 has the unprecedented ability to inhibit both the EGF receptor (EGFR) and FGFR covalently by targeting two distinct cysteine residues. We report the cocrystal structure of FGFR4 with FIIN-2, which unexpectedly exhibits a "DFG-out" covalent binding mode. The structural basis for dual FGFR and EGFR targeting by FIIN3 also is illustrated by crystal structures of FIIN-3 bound with FGFR4 V550L and EGFR L858R. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance and provide the first example, to our knowledge, of a kinase inhibitor that covalently targets cysteines located in different positions within the ATP-binding pocket.
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http://dx.doi.org/10.1073/pnas.1403438111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4234547PMC
November 2014
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