Recombinant Mouse FGF-9

Recombinant mouse FGF-9 offers several compelling advantages for research applications across multiple biological systems and therapeutic contexts.

Cardiovascular Research and Therapeutic Potential

Recombinant FGF-9 demonstrates significant therapeutic promise in cardiac research. Conditional expression of FGF-9 in adult mouse myocardium promotes myocardial vascularization and hypertrophy with enhanced systolic function and markedly reduced heart failure mortality after myocardial infarction. The protein stimulates left ventricular hypertrophy with microvessel expansion, reduces interstitial fibrosis, and attenuates fetal gene expression—all while preserving diastolic function and improving systolic performance. These effects occur through both direct and indirect mechanisms, with FGF-9 stimulating endothelial cells to release prohypertrophic factors that promote cardiomyocyte growth.

Cellular Differentiation Studies

Recombinant FGF-9 serves as a valuable tool for investigating myogenic differentiation pathways. At concentrations as low as 10 ng/mL, FGF-9 effectively inhibits myogenic differentiation in muscle cell models, decreasing expression of key myogenic regulatory genes like MyoG and Mhc while increasing Myostatin expression. This makes it particularly useful for studying the molecular mechanisms controlling muscle cell fate decisions and the regulatory networks governing myogenesis.

Developmental and Tissue-Specific Applications

FGF-9 plays critical roles in multiple developmental processes. The protein is essential for skeletal development, cerebellar formation, lung development, cardiac development, vascular system formation, and digestive tract development. Additionally, FGF-9 participates in palatogenesis by facilitating palatal growth and timely elevation through regulation of cell proliferation and hyaluronic acid accumulation.

Receptor Specificity and Signaling

Recombinant FGF-9 efficiently activates the "c" splice forms of FGFR2 and FGFR3, providing specificity in studying fibroblast growth factor receptor signaling pathways. This receptor selectivity enables targeted investigation of FGF signaling mechanisms in cells expressing these particular receptor isoforms.

Quality and Reproducibility

High-purity recombinant FGF-9 preparations (>95% purity) are available for research use, ensuring reproducible results in bioactivity assays and consistent experimental outcomes across multiple applications.

You can use recombinant mouse FGF-9 as a standard for quantification or calibration in ELISA assays, provided it is compatible with your assay system and matches the native protein recognized by your ELISA antibodies. Recombinant proteins are commonly used as standards in quantitative ELISA protocols, and many commercial ELISA kits for FGF-9 use recombinant mouse FGF-9 as their standard.

Key considerations:

• Source and Purity: The recombinant FGF-9 should be of high purity and preferably from a source with validated biological activity comparable to the native protein.
• Carrier Protein: Some recombinant proteins are supplied with carrier proteins (e.g., BSA) to enhance stability. For ELISA calibration, using a formulation with BSA is often recommended to mimic the sample matrix and reduce adsorption losses.
• Expression System: The expression system (E. coli, yeast, mammalian) can affect post-translational modifications. Most ELISA antibodies recognize linear epitopes, so E. coli-expressed FGF-9 is generally suitable, but confirm that your assay is validated for the recombinant form you intend to use.
• Standard Curve Preparation: Prepare a serial dilution of the recombinant FGF-9 in the same diluent as your samples to generate a standard curve. Ensure the concentration range covers the expected sample values.
• Validation: Confirm that the recombinant standard produces a dose-response curve parallel to that of endogenous FGF-9 in your samples. This ensures accurate quantification.

Best Practices:

• Always check the ELISA kit manual for recommendations regarding standard preparation and compatibility with recombinant proteins.
• If using a custom or in-house ELISA, validate the recombinant FGF-9 standard by comparing its response to that of endogenous FGF-9 in representative samples.
• Use freshly prepared or properly stored aliquots of the recombinant standard to maintain consistency and avoid degradation.

Summary Table: Recombinant Mouse FGF-9 as ELISA Standard

In summary: Recombinant mouse FGF-9 is suitable as a standard for ELISA quantification if it is compatible with your assay and validated for parallelism with native FGF-9. Always follow best practices for standard preparation and assay validation to ensure accurate results.

Recombinant Mouse FGF-9 has been validated in published research for several key applications, primarily in studies of angiogenesis, osteogenesis, bone remodeling, thermogenesis, myogenic differentiation, and tissue regeneration.

Key validated applications include:

• Angiogenesis and Osteogenesis Assays
  Recombinant mouse FGF-9 has been used in bioassays to enhance angiogenesis (formation of new blood vessels) and osteogenesis (bone formation), particularly in models of bone regeneration and tissue repair. Studies show that FGF-9, often in combination with VEGFA, significantly increases bone regeneration and vascularization in mouse models.

• Bone Remodeling and Regeneration
  FGF-9 has been applied to promote bone remodeling and repair in vivo, with effects measured by immunohistochemistry for markers such as PCNA, RUNX-2, and Osteocalcin in mouse tibia defect models.

• Thermogenesis and Metabolic Regulation
  In vivo administration of recombinant mouse FGF-9 increases UCP1 expression and thermogenic capacity in adipose tissue, improving cold tolerance and metabolic activity in mice.

• Myogenic Differentiation and Muscle Biology
  Recombinant FGF-9 has been shown to inhibit myogenic differentiation in C2C12 myoblasts and human skeletal muscle cells, affecting gene expression related to muscle development and intracellular calcium homeostasis. It also stimulates myoblast proliferation.

• Neuronal and Prostate Tissue Growth
  FGF-9 acts as an autocrine/paracrine growth factor supporting the growth and survival of motor neurons and prostate tissue.

• Sex Determination and Gonadal Development
  Mouse models lacking FGF-9 display sex reversal phenotypes, indicating its role in testicular embryogenesis and sex determination.

• Hair Follicle Cycle Regulation
  Recombinant FGF-9 has been used to promote hair follicle growth and accelerate hair cycle transitions in mice, with effects on skin pigmentation and follicle morphology.

• Cell Proliferation and Migration Assays
  FGF-9 has been validated for use in cell proliferation and migration assays, particularly in studies of tissue regeneration and cancer biology.

Experimental formats validated:

• In vivo administration (systemic or local injection in mice)
• In vitro cell culture assays (proliferation, differentiation, migration)
• Immunohistochemistry and molecular marker analysis
• Gene expression studies (RT-qPCR, PCR arrays)

Summary:
Recombinant mouse FGF-9 is a well-validated tool in published research for studying vascular and bone biology, muscle differentiation, metabolic regulation, neuronal and prostate tissue growth, sex determination, hair follicle cycling, and cell proliferation/migration. Its applications span both in vivo and in vitro experimental systems, with robust evidence supporting its biological activity in these contexts.

To reconstitute and prepare Recombinant Mouse FGF-9 protein for cell culture experiments, first centrifuge the vial to collect the lyophilized powder at the bottom, then reconstitute with sterile distilled water to a concentration of 0.1–0.5 mg/mL; avoid vortexing or vigorous pipetting, and for long-term storage, add a carrier protein such as 0.1% BSA, aliquot, and store at -70°C.

Detailed protocol and best practices:

• Centrifugation: Briefly centrifuge the vial before opening to ensure all powder is at the bottom.
• Reconstitution: Add sterile distilled water to achieve a final concentration of 0.1–0.5 mg/mL. For example, to reconstitute 100 μg, add 1 mL for 0.1 mg/mL or 200 μL for 0.5 mg/mL.
• Mixing: Gently pipette the solution down the sides of the vial to dissolve. Do not vortex or pipette vigorously to avoid protein denaturation.
• Carrier protein: For long-term storage or to prevent adsorption and loss of activity, add a stabilizer such as 0.1% BSA, 5% HSA, 10% FBS, or 5% trehalose.
• Aliquoting: Divide the reconstituted protein into small aliquots to minimize freeze-thaw cycles.
• Storage: Store aliquots at -70°C for long-term stability. Avoid repeated freeze-thaw cycles.
• Working solution: For cell culture, dilute the stock solution further in cell culture medium or appropriate buffer immediately before use. The effective working concentration for cell assays is typically in the ng/mL range (e.g., 2.5–10 ng/mL for proliferation assays).
• Handling: Warm the lyophilized powder to room temperature before opening to prevent condensation.

Summary Table: Recombinant Mouse FGF-9 Reconstitution

Additional notes:

• Always consult the specific product datasheet for any unique formulation or buffer requirements, as some preparations may contain stabilizers or require specific pH conditions.
• Avoid using buffers containing surfactants or organic solvents for reconstitution or dilution, as these can denature the protein.

This protocol ensures optimal activity and stability of recombinant FGF-9 for cell culture applications.