Recombinant Human FGF-7

Recombinant Human FGF-7 (also known as Keratinocyte Growth Factor, KGF) is widely used in research due to its potent and specific effects on epithelial cell biology, making it valuable for studies in cell proliferation, differentiation, tissue repair, and organ development.

Key reasons to use recombinant human FGF-7 in research applications:

• Selective Mitogen for Epithelial Cells: FGF-7 specifically stimulates the proliferation and migration of epithelial cells, including keratinocytes, without affecting fibroblasts or endothelial cells. This selectivity is crucial for dissecting epithelial-specific signaling pathways and cellular responses.

• Wound Healing and Tissue Repair: FGF-7 is upregulated after epithelial injury and plays a central role in tissue regeneration and repair, making it essential for in vitro wound healing models and studies of epithelial barrier function.

• Developmental Biology: FGF-7 is involved in embryonic development, particularly in branching morphogenesis of organs such as the kidney and lung, and in the formation of the apical ectodermal ridge during limb development.

• Disease Modeling and Therapeutic Research: FGF-7 has been used to model diseases involving epithelial dysfunction, such as chemotherapy-induced mucositis, and to study epithelial protection in organoid and stem cell-derived systems.

• High Biological Activity and Purity: Recombinant forms are produced to be highly pure and biologically active, ensuring reproducible results in functional assays, cell culture, and differentiation protocols.

• Paracrine Signaling Studies: FGF-7 acts as a paracrine effector, allowing investigation of stromal-epithelial interactions and their roles in tissue homeostasis and pathology.

• Animal-Free and Human Cell-Expressed Options: Recombinant FGF-7 can be produced in human cell systems, providing native folding, glycosylation, and higher stability and activity, which are advantageous for translational and clinical research.

Typical applications include:

• Epithelial cell proliferation and differentiation assays
• Wound healing and tissue regeneration models
• Organoid culture and maintenance
• Developmental biology studies (e.g., kidney, lung, limb development)
• Disease modeling (e.g., mucositis, epithelial injury)
• Functional studies of paracrine signaling in epithelial-stromal interactions

In summary, recombinant human FGF-7 is a critical tool for research focused on epithelial biology, tissue engineering, regenerative medicine, and developmental processes due to its specificity, potency, and relevance to both basic and translational science.

Yes, recombinant Human FGF-7 can be used as a standard for quantification or calibration in ELISA assays, provided it is properly prepared and validated for your specific assay system. Recombinant FGF-7 is commonly used as a standard in commercial ELISA kits designed to quantify both natural and recombinant forms of FGF-7 in biological samples.

Key considerations and best practices:

• Standard Preparation: The recombinant FGF-7 should be reconstituted and diluted according to the ELISA kit protocol or your assay’s requirements. Use the recommended buffer (often a protein-based calibrator diluent) to ensure stability and compatibility with the assay.
• Validation: Confirm that the dose-response curve of your recombinant FGF-7 standard is parallel to that of endogenous FGF-7 in your sample matrix. This ensures accurate quantification and comparability between recombinant and natural protein.
• Source and Purity: Use highly purified recombinant FGF-7, ideally expressed in a system that yields a protein similar to the native form (e.g., glycosylation status, folding), as differences may affect antibody recognition and quantification.
• Research Use: Standards and ELISA kits are generally for research use only and not for diagnostic procedures.
• Lot-to-Lot Consistency: Always use fresh standards for each assay and avoid mixing reagents from different lots to minimize variability.

Protocol Example (based on typical ELISA kit instructions):

1. Reconstitute recombinant FGF-7 to a defined concentration (e.g., 20,000 pg/mL) in the recommended buffer.
2. Prepare a serial dilution series to generate a standard curve covering the assay’s dynamic range.
3. Run the ELISA with your samples and standards in parallel.
4. Interpolate sample concentrations from the standard curve.

Summary Table: Recombinant FGF-7 as ELISA Standard

In conclusion, recombinant Human FGF-7 is suitable as a standard for ELISA quantification and calibration, provided you follow best practices for preparation, validation, and assay execution.

Recombinant Human FGF-7 (Keratinocyte Growth Factor, KGF) has been validated in published research for a range of applications primarily involving cell proliferation, differentiation, tissue morphogenesis, epithelial protection, and repair.

Key validated applications include:

• Bioassays: Used to stimulate proliferation of epithelial cells, including keratinocytes and pancreatic progenitor cells, and to assess functional activity in various cell types.
• Cell Culture: Supports growth and differentiation of human pluripotent stem cells, organoids, and epithelial cell lines; commonly used in protocols for tissue engineering and regenerative medicine.
• Functional Assays: Evaluates biological activity such as induction of cell proliferation, migration, and differentiation, especially in epithelial and progenitor cells.
• Wound Healing Studies: Demonstrated to promote epithelial repair and regeneration in vitro and in animal models.
• Organoid and Tissue Development: Facilitates branching morphogenesis and complex tissue formation in organoid models of lung, liver, gastrointestinal tract, and mammary gland.
• Cancer Research: Investigated for its role in tumor cell proliferation, migration, invasion, and modulation of tumor microenvironment, particularly in ovarian and esophageal cancers.
• Stem Cell Differentiation: Used to promote differentiation of pancreatic endocrine progenitor cells into insulin-secreting beta cells and to support ES/iPS cell culture.
• Molecular and Biochemical Assays: Validated for use in ELISA, Western blot, blocking assays, immunohistochemistry, SDS-PAGE, HPLC, and mass spectrometry for protein characterization and quantification.

Representative published research applications:

• Organoid bioassays for lung and corneal epithelial differentiation.
• Large-scale production of islet-like clusters for diabetes research.
• Pancreatic progenitor differentiation studies using human pluripotent stem cells.
• Cancer cell proliferation and migration assays in ovarian cancer models.
• Wound healing and epithelial repair models in vitro and in vivo.

Summary Table of Validated Applications

These applications are supported by multiple peer-reviewed studies and product validation data, confirming the utility of recombinant human FGF-7 in diverse research contexts related to epithelial biology, regenerative medicine, and disease modeling.

Reconstitution Protocol

Pre-reconstitution preparation is critical for optimal protein recovery. Before opening the lyophilized vial, briefly centrifuge it in a microcentrifuge for 20-30 seconds to consolidate any protein that may be adhered to the cap, sides, or bottom of the vial. Allow the lyophilized powder to warm to room temperature before opening to improve solubility.

Reconstitution buffer and concentration depend on your specific application and product formulation. The recommended reconstitution concentration ranges from 0.1 to 1.0 mg/mL in sterile solutions. Common reconstitution buffers include:

• Phosphate-buffered saline (PBS) at pH 7.4, which is the most widely recommended option
• Sterile distilled water, which works for most recombinant proteins
• Tris buffer (5 mM, pH 7.6) for specific formulations

Carrier protein addition is strongly recommended for both reconstitution and storage stability. Add 0.1% human serum albumin (HSA) or bovine serum albumin (BSA) to your reconstitution buffer. This carrier protein significantly improves protein stability and prevents non-specific adsorption to container surfaces.

Mixing technique is essential to avoid protein denaturation. Gently swirl or tap the vial to mix the reconstituted protein—do not vortex or mix vigorously. If solubility issues persist after gentle mixing, allow the reconstituted protein to incubate overnight at 4°C.

Storage and Stability

Short-term storage of reconstituted protein can be maintained at 2-8°C for up to 1 week. This is suitable for immediate experimental use.

Extended storage requires working aliquots containing at least 10 µL of protein solution with carrier protein stored at -20°C to -80°C. Use a manual defrost freezer to minimize temperature fluctuations.

Critical storage consideration: Avoid repeated freeze-thaw cycles, as these significantly compromise protein activity and integrity.

Verification of Reconstitution

After reconstitution, confirm successful protein recovery by running a small aliquot on SDS-PAGE under reducing conditions. A protein band at the expected molecular weight (approximately 20 kDa for FGF-7) should be visible with as little as 10 ng of protein loaded on the gel.

Troubleshooting

If you encounter solubility issues, verify that you are using the recommended buffer specified in your product's certificate of analysis or data sheet, as some formulations may require specific pH conditions. Do not exceed a reconstitution concentration of 1 mg/mL, as this can exacerbate solubility problems.