Recombinant Human FGF-22

Recombinant Human FGF-22 is used in research applications primarily for its roles in synaptic organization, neural development, and tissue regeneration. It is particularly valuable for studies involving neuronal connectivity, synaptic plasticity, and tissue repair mechanisms.

Key scientific reasons to use Recombinant Human FGF-22 include:

• Synaptic Organization and Neural Development: FGF-22 is expressed by postsynaptic (target) cells and acts as an organizer of the presynaptic apparatus. It binds to FGF receptor 2b (FGFR2b) on innervating neurons, promoting synaptic vesicle clustering, neurite branching, and the formation of functional synapses. This makes it a critical tool for investigating synaptogenesis and neural circuit formation in vitro and in vivo.

• Hearing and Sensory Research: In the inner ear, FGF-22 is expressed in inner hair cells and is essential for maintaining ribbon synapse numbers, which are crucial for auditory function. It is used to study mechanisms underlying hearing maintenance and sensory neuron connectivity.

• Tissue Repair and Regeneration: Like other FGFs, FGF-22 is implicated in tissue repair processes, including wound healing and regeneration of damaged tissues. Its application can help elucidate the molecular pathways involved in tissue homeostasis and recovery after injury.

• Modeling Disease and Developmental Disorders: Because FGF-22 signaling is involved in synaptic organization, it is relevant for modeling neurodevelopmental disorders, neurodegeneration, and diseases affecting synaptic function.

• Defined, Reproducible Experimental Conditions: Using recombinant human FGF-22 allows for precise control over concentration and purity, reducing variability compared to tissue extracts and enabling reproducible results in cell culture, organoid, or animal models.

Additional considerations:

• FGF-22 is distinct from other FGFs (such as FGF-2/bFGF) in its specific roles in synaptic and neural tissue organization, making it the preferred choice for studies focused on these processes.
• Recombinant proteins are typically produced to high purity and bioactivity, ensuring minimal contamination and batch-to-batch consistency, which is critical for sensitive biological assays.

In summary, use recombinant human FGF-22 when your research requires a defined factor to study synaptic development, neural connectivity, sensory function, or tissue regeneration, and when experimental reproducibility and specificity are essential.

Recombinant Human FGF-22 can be used as a standard for quantification or calibration in ELISA assays, provided it is of high purity and correctly formulated for this purpose.

For use as an ELISA standard:

• Purity and Formulation: The recombinant FGF-22 should be highly purified and, ideally, supplied with a carrier protein such as BSA to enhance stability and reproducibility in standard curve preparation. Carrier-free formulations are also available if BSA interferes with your assay.
• Reconstitution: Follow the manufacturer’s instructions for reconstitution, typically in PBS with at least 0.1% serum albumin to prevent adsorption and loss of protein activity.
• Standard Curve Preparation: Prepare serial dilutions of the recombinant FGF-22 to generate a standard curve covering the expected concentration range in your samples. Most ELISA kits for FGF-22 recommend standard curves in the range of approximately 15–10,000 pg/mL, depending on assay sensitivity.
• Validation: Ensure that the antibodies used in your ELISA specifically recognize the recombinant FGF-22 and that the standard curve is linear and reproducible within your assay’s dynamic range. It is best practice to confirm that the recombinant standard behaves similarly to endogenous FGF-22 in your sample matrix.

Additional considerations:

• If your ELISA kit is designed for FGF-22, verify that the recombinant standard matches the sequence and post-translational modifications (if any) of the native protein recognized by the kit antibodies.
• For highest accuracy, use the same recombinant FGF-22 protein as the standard that was used to calibrate the commercial ELISA kit, if possible. If using a different source, confirm equivalency by comparing standard curves or performing spike-and-recovery experiments.
• Avoid repeated freeze-thaw cycles of the recombinant standard to maintain protein integrity.

In summary, recombinant human FGF-22 is suitable as an ELISA standard if it is pure, stable, and compatible with your assay antibodies and protocol. Always validate its performance in your specific assay context.

Recombinant Human FGF-22 has been validated in published research primarily for applications related to bioassays involving synaptogenesis, neuronal development, and functional recovery after nervous system injury, as well as for use as a control in immunological assays such as SDS-PAGE.

Key validated applications include:

• Bioassays in neuronal and myotube cultures: FGF-22 has been used to study its role as a presynaptic organizer, promoting synaptic vesicle clustering, synapse formation, and neurite branching in neurons and myotubes. These bioassays typically involve whole cell systems from rat or human sources.

• Functional studies in spinal cord injury models: FGF-22 has been delivered via gene therapy (e.g., rAAV-mediated overexpression) to enhance synaptogenesis, circuit rewiring, and functional recovery following spinal cord injury in animal models. These studies validate its use in both in vitro neuronal cultures and in vivo animal models for neuroregeneration research.

• Immunological assays: Recombinant FGF-22 has been validated as a control protein in SDS-PAGE and is suitable for use in immunological assays to detect or quantify FGF-22 using polyclonal or monoclonal antibodies.

• General research on synapse formation and maturation: FGF-22 is recognized as a mediator of synaptogenesis in the adult nervous system, and recombinant forms are used to study its regulatory effects on synapse formation and maturation.

Summary Table of Validated Applications

Additional Notes:

• Most published research focuses on the nervous system, particularly synaptic development and repair.
• Applications in other systems (e.g., angiogenesis, wound healing) are well-documented for other FGF family members, but not specifically validated for FGF-22 in the provided literature.
• Recombinant FGF-22 is generally supplied for research use only and not for therapeutic or diagnostic applications.

If you require protocols or more detailed application notes for a specific experimental setup, please specify the context (e.g., cell type, animal model, assay type).

To properly reconstitute and prepare Recombinant Human FGF-22 protein for cell culture experiments, follow these best practices based on manufacturer and scientific recommendations:

Reconstitution

1. Centrifuge the vial before opening to ensure all lyophilized powder is at the bottom.
2. Reconstitute the protein in sterile PBS or sterile water to a concentration of 100 µg/mL.
   • Some protocols recommend using sterile PBS containing at least 0.1% human or bovine serum albumin (BSA) to stabilize the protein and prevent adsorption to surfaces.
   • If your protein is carrier-free, adding 0.1% BSA to the reconstitution buffer is advisable for cell culture applications.
3. Gently mix the solution by pipetting up and down or swirling the vial. Do not vortex, as this can denature the protein.
4. Allow the solution to sit at room temperature for at least 20 minutes to ensure complete dissolution.

Dilution for Cell Culture

• After reconstitution, further dilute the stock solution in your cell culture medium or assay buffer.
• For most cell culture applications, prepare working dilutions in buffer containing 0.1% BSA to maintain protein stability and activity.

Storage

• Short-term storage: Store the reconstituted protein at 2–8°C for up to 1 week.
• Long-term storage: Aliquot and store at –20°C to –80°C in a manual defrost freezer. Avoid repeated freeze-thaw cycles to prevent protein degradation.

Additional Tips

• Always refer to the specific product datasheet or Certificate of Analysis (COA) for any unique instructions related to your protein batch.
• For sensitive cell culture experiments, consider testing the activity of the reconstituted protein in a pilot assay.

By following these steps, you will maximize the stability and biological activity of Recombinant Human FGF-22 for your cell culture experiments.