Recombinant Human FGF-8e

Recombinant Human FGF-8e is used in research applications primarily for its critical roles in embryonic development, neural patterning, cell proliferation, and tissue regeneration.

FGF-8e is a member of the fibroblast growth factor family, which is essential for mediating epithelial-mesenchymal transitions, regional patterning of the brain, and organogenesis during embryogenesis. Specifically, FGF-8e has been shown to:

• Regulate regional identity and cellular diversity in neural tissues: FGF-8 signaling directly influences the patterning of forebrain and midbrain regions in human cerebral organoids, modulating gene expression (e.g., FOXG1, NR2F1) and affecting the balance of excitatory and inhibitory neurons.
• Promote cell proliferation, differentiation, and migration: FGF-8e stimulates mitogenic activity, supporting the expansion and self-renewal of neural progenitors and other cell types.
• Support tissue regeneration: Recombinant FGFs, including FGF-8e, are widely used to induce regeneration in damaged tissues such as nerve, bone, cartilage, and muscle, due to their potent biological activity.
• Enable controlled experimental conditions: Recombinant proteins provide high purity and batch-to-batch consistency, which is crucial for reproducible results in bioassays, stem cell differentiation protocols, and developmental biology studies.

FGF-8e isoform-specific features:

• FGF-8e, along with other isoforms, activates specific FGF receptors (FGFR2, FGFR3, FGFR4) with differential biological effects, allowing for targeted studies of receptor-mediated signaling pathways.
• FGF-8e has transforming activity and has been detected in certain human tumors, making it relevant for cancer biology research.

Typical applications include:

• Neural differentiation of human pluripotent stem cells
• Patterning and regionalization studies in organoid models
• Tissue engineering and regenerative medicine
• Cancer biology and developmental signaling pathway analysis

Using recombinant human FGF-8e ensures precise control over experimental variables, enabling detailed mechanistic studies and translational research in developmental biology, neuroscience, and regenerative medicine.

Recombinant Human FGF-8e can be used as a standard for quantification or calibration in ELISA assays, provided it is compatible with your assay's antibody specificity and format.

Key considerations and supporting details:

• Carrier Protein: For use as an ELISA standard, it is generally recommended to use the recombinant protein formulated with a carrier protein such as BSA, as this enhances stability and reproducibility. Carrier-free forms are typically reserved for applications where BSA may interfere, but can also be used if your assay is validated for carrier-free standards.

• Isoform Specificity: FGF-8 exists in multiple isoforms (e.g., FGF-8a, FGF-8b, FGF-8e). Ensure that your ELISA antibodies recognize the FGF-8e isoform specifically, or that the assay is validated for all FGF-8 isoforms. Some commercial ELISA kits are designed to detect total FGF-8 and may not distinguish between isoforms.

• Standard Curve Validation: When using a recombinant protein as a standard, you must validate that the standard curve generated with recombinant FGF-8e is parallel to the curve generated with native FGF-8 in your sample matrix. This ensures accurate quantification and that the recombinant standard behaves similarly to the endogenous protein in your assay conditions.

• Concentration Range: Prepare your standard curve within the detection range of your ELISA kit (e.g., 31.25 pg/mL – 1000 pg/mL for some FGF-8 kits). Reconstitute the recombinant protein according to the manufacturer's instructions (e.g., 500 μg/mL in sterile PBS for some FGF-8e preparations).

• Assay Validation: If your ELISA kit is not specifically validated for recombinant FGF-8e as a standard, you should perform a validation experiment to confirm that the recombinant standard provides accurate and reproducible results in your assay system.

• Scientific Use: Most ELISA kits and recombinant standards are for research use only and not for clinical diagnostics.

Summary of best practices:

• Use recombinant FGF-8e with BSA as a standard unless BSA interferes with your assay.
• Confirm antibody specificity for FGF-8e or validate cross-reactivity.
• Validate the standard curve for parallelism and accuracy.
• Use within the recommended concentration range and storage conditions.

If you follow these guidelines and validate your assay appropriately, recombinant human FGF-8e is suitable as a standard for quantification or calibration in ELISA assays.

Recombinant Human FGF-8e has been validated primarily for use in bioassays involving cell-based functional studies, particularly in the context of embryonic development and neural differentiation. Published research demonstrates its application in:

• Bioassays for developmental biology: FGF-8e has been used to study its role in embryogenesis, including the regulation of epithelial-mesenchymal transitions, gastrulation, and patterning of the midbrain/hindbrain, eye, ear, limbs, and heart.
• Neural differentiation protocols: It has been validated in protocols for the efficient derivation of functional floor plate tissue from human embryonic stem cells, as well as in the generation and characterization of neural rosettes, which represent early neural stem cell stages.
• Tumor biology studies: FGF-8e, along with other isoforms, has been detected in human tumors (such as prostate, breast, and ovarian cancers), and is used in research exploring its transforming and oncogenic potential.

Key published studies validating these applications include:

• Fasano et al., Cell Stem Cell (2010): Used FGF-8e in bioassays to derive floor plate tissue from human embryonic stem cells.
• Elkabetz et al., Genes Dev. (2008): Applied FGF-8e in bioassays to study early neural stem cell stages in human ES cell-derived neural rosettes.

Summary of validated applications:

• Cell-based bioassays (functional studies of growth, differentiation, and patterning)
• Neural induction and differentiation from pluripotent stem cells
• Developmental biology research (embryogenesis, tissue patterning)
• Cancer biology (expression and function in tumors)

No evidence was found in the provided results for use in ELISA, Western blot, or immunohistochemistry; the primary validated application is in cell-based functional assays.

To reconstitute and prepare Recombinant Human FGF-8e protein for cell culture experiments, follow these key steps:

• Centrifuge the vial briefly before opening to ensure all lyophilized protein is at the bottom.
• Reconstitute the protein in a suitable buffer. For FGF-8e, a common protocol is to use sterile PBS (phosphate-buffered saline) to achieve a concentration of 500 μg/mL. If your product datasheet specifies a different buffer (e.g., Tris-HCl or water with 0.1% human serum albumin), follow those instructions.
• Mix gently by pipetting up and down or gentle vortexing. Avoid vigorous agitation to prevent protein denaturation.
• Aliquot the reconstituted protein to avoid repeated freeze-thaw cycles, which can reduce activity.
• Storage after reconstitution:
  • At 2–8 °C for up to 1 month.
  • At –20 °C to –70 °C for up to 3 months.
  • At 4 °C for short-term use (up to 1 week), but avoid repeated freeze-thaw cycles.

Additional recommendations for cell culture use:

• For working solutions, dilute the reconstituted stock in cell culture medium or buffer containing a carrier protein such as 0.1% BSA or recombinant human serum albumin to minimize adsorption and stabilize the protein.
• Filter sterilize if necessary, using a 0.2 μm filter.
• Always consult the product’s Certificate of Analysis or datasheet for isoform-specific instructions, as formulations and recommended buffers may vary.

Summary protocol example for FGF-8e:

1. Briefly centrifuge the vial.
2. Add sterile PBS to achieve 500 μg/mL.
3. Mix gently until fully dissolved.
4. Aliquot and store at –20 °C to –70 °C for long-term, or 2–8 °C for short-term use.
5. Dilute into culture medium with carrier protein just before use.

These steps will help maintain the bioactivity and stability of FGF-8e for reliable cell culture experiments.