Parathyroid Hormone-Related Protein (PTHrP) is a versatile, multifunctional protein hormone expressed and secreted by a wide range of tissues throughout the body, including epithelium, mesenchyme, vascular smooth muscle, and the central nervous system. It plays critical roles in both fetal and postnatal life .
Key Biological Functions of PTHrP
PTHrP is essential in several physiological systems:
Vascular & Smooth Muscle Regulation: PTHrP is often secreted by smooth muscle cells (e.g., in the vasculature) in response to stretching. It acts as a powerful vasodilator by promoting the relaxation of vascular smooth muscle, significantly contributing to the cardiovascular system's function. It is also implicated in the contraction of other smooth muscles, such as those in the bladder, uterus, and heart.
Skeletal Development & Bone Health: PTHrP is vital for skeletal development, regulating the proliferation and differentiation within the cranial growth plate. Furthermore, it exhibits potent anabolic effects on bone, showing promise in treating conditions like postmenopausal osteoporosis. It promotes the recruitment of osteogenic cells and prevents the apoptotic death of crucial bone cells (osteoblasts and osteocytes).
Disease Involvement: PTHrP is a key molecular player in several pathological states, most notably
Humoral Hypercalcemia of Malignancy (HHM): PTHrP is a primary causative factor for this paraneoplastic syndrome, leading to elevated calcium levels.
Cancer Cachexia: Independent of hypercalcemia, PTHrP contributes to cachexia, a debilitating condition characterized by reduced food intake, body weight loss, and decreased locomotor activity.
PTHrP Human Recombinant is produced in E. Coli and consists of a single, non-glycosylated polypeptide chain comprising 86 amino acids. The protein has a calculated molecular weight (MW) of 9.9kDa. It is purified to high homogeneity using a series of proprietary chromatographic techniques.
Formulation
The PTHrP protein was lyophilized from a 0.2 µm filtered concentrated solution prepared in 1x Phosphate-Buffered Saline (PBS), pH 7.2 - 7.4.
Reconstitution
Reconstitute the lyophilized PTHrP in sterile 18 MΩ-cm H₂O to a minimum concentration of 100 µg/ml. The solution can then be diluted in other aqueous buffers.
Storage and Stability
- Lyophilized Material: Stable for up to 3 weeks at room temperature; however, we recommend storage below -20°C in a desiccated environment for long-term stability.
-Reconstituted Solution (Short Term): Store at 2°C to 7°C (refrigerator) for 2 to 7 days.
Reconstituted Solution (Long Term): Store below -20°C. For extended stability, add a carrier protein (e.g., 0.1% HSA or BSA) prior to freezing.
Handling Note: Avoid repeated freeze-thaw cycles to maintain activity.
Country of Origin
USA
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Recombinant Human PTHrP (Parathyroid Hormone-related Protein) is used in research applications to study and manipulate processes such as bone formation, osteoclastogenesis, cell differentiation, and tissue regeneration, due to its potent biological effects on skeletal and extraskeletal tissues.
Key reasons to use recombinant human PTHrP in research include:
Bone Regeneration and Osteogenesis: PTHrP promotes osteogenic differentiation and bone formation, making it valuable for studies on osteoporosis, bone defect repair, and skeletal tissue engineering. For example, recombinant PTHrP has been shown to enhance osteoblast proliferation and differentiation, and its local application in bioactive scaffolds accelerates bone repair in osteoporotic models.
Cellular Differentiation and Proliferation: PTHrP regulates chondrocyte and osteoblast differentiation, as well as the proliferation of various cell types, including mesenchymal stem cells and epithelial cells. This makes it a useful tool for developmental biology and regenerative medicine studies.
Macrophage Polarization and Immune Modulation: PTHrP can influence the immune microenvironment by promoting macrophage polarization toward the M2 phenotype, which is associated with tissue repair and anti-inflammatory effects.
Disease Modeling and Therapeutic Research: Recombinant PTHrP is used to model diseases such as osteoporosis, osteoarthritis, and certain cancers, and to test potential therapeutic interventions targeting PTHrP pathways.
Controlled and Reproducible Experiments: Using recombinant protein ensures batch-to-batch consistency, defined activity, and the ability to precisely control dosing and experimental conditions, which is critical for reproducible research outcomes.
Mechanistic Studies: Recombinant PTHrP allows for the dissection of specific signaling pathways (e.g., PTH1R-mediated signaling) and the study of its effects on gene expression, cell signaling, and tissue remodeling.
In summary, recombinant human PTHrP is a versatile tool for investigating bone biology, tissue regeneration, cell signaling, and disease mechanisms, offering precise control and reproducibility in experimental systems.
Yes, recombinant human PTHrP can be used as a standard for quantification or calibration in ELISA assays, provided it is properly characterized and compatible with your assay system.
Several sources confirm that recombinant human PTHrP is commonly supplied as a standard in ELISA kits for generating standard curves. For example:
The product information from Antigenix (result ) explicitly states that the standard provided is 10.0 µg of recombinant human PTHrP, which is reconstituted and used to prepare a standard curve for quantification.
Multiple ELISA kit manuals (e.g., results , , , ) describe the use of recombinant human PTHrP as the standard to construct a standard curve for quantifying PTHrP in samples.
The purity and form of the recombinant protein (e.g., lyophilized, >98% purity by SDS-PAGE and HPLC, as noted in result ) are important for accurate calibration.
Key considerations:
Ensure the recombinant PTHrP standard is compatible with the antibodies used in your ELISA (i.e., it should be recognized by both capture and detection antibodies).
Reconstitute and dilute the standard according to the manufacturer’s instructions or validated protocols.
Always prepare fresh standard dilutions for each assay, as working standards may not be stable over time.
Validate the standard curve in your specific assay matrix to confirm linearity and recovery.
In summary, recombinant human PTHrP is suitable for use as a standard in ELISA assays for quantification or calibration, as long as it is handled and validated appropriately.
Recombinant Human Parathyroid Hormone-Related Protein (PTHrP) has been validated for several key applications in published research, primarily in the fields of bone biology, endocrinology, cancer, and metabolic disease.
Validated Applications:
Osteoporosis and Bone Regeneration Models
Recombinant human PTHrP (both 1-34 and 1-84 fragments) has been used in animal models (e.g., ovariectomized mice) to study its effects on bone formation, bone density, and renal calcium reabsorption. These studies demonstrate that PTHrP enhances bone formation and may be more effective than PTH in certain contexts.
PTHrP has been incorporated into bioactive scaffolds for local delivery to bone defects, showing promotion of osteoblast activity, inhibition of osteoclastogenesis, and facilitation of bone repair in osteoporotic rat models.
Cellular Assays
PTHrP has been used to assess proliferation, differentiation, and polarization of cell lines such as MC3T3-E1 (pre-osteoblasts) and RAW264.7 (macrophages), demonstrating effects on cell growth, viability, and function in vitro.
It has also been applied to human breast cancer cell lines (MCF-7) to evaluate biological activity and cellular responses.
Endocrine and Metabolic Research
Recombinant PTHrP has been used to study its role in glucose metabolism, specifically its ability to induce pancreatic beta cell proliferation and improve glucose-stimulated insulin secretion.
Cancer Biology
PTHrP is frequently studied for its role in cancer progression, particularly in breast and prostate cancer, where it is implicated in tumor growth and bone metastasis. Recombinant PTHrP has been used in vitro to investigate mechanisms of cancer cell signaling and interaction with the bone microenvironment.
Protein Cleavage and Biochemical Characterization
Recombinant human PTHrP has been used in biochemical assays to study its cleavage by enzymes such as prostate-specific antigen (PSA), helping to elucidate post-translational modifications and functional domains.
Most studies use recombinant PTHrP fragments (e.g., 1-34, 1-36, 1-84, 1-141) depending on the specific biological question.
Applications are primarily preclinical and research-focused; clinical use is limited and investigational.
These validated applications demonstrate the versatility of recombinant human PTHrP in bone biology, metabolic research, cancer studies, and protein biochemistry.
To reconstitute and prepare Recombinant Human PTHrP (Parathyroid Hormone-related Protein) for cell culture experiments, follow these best-practice steps:
Centrifuge the vial briefly before opening to ensure all lyophilized material is at the bottom.
Reconstitute the protein in sterile, high-purity water (e.g., 18 MΩ-cm H₂O) or sterile distilled water. The recommended concentration is typically 100 µg/mL to 1 mg/mL.
For improved stability and to minimize adsorption, you may use an aqueous buffer containing 0.1% BSA (bovine serum albumin) as a carrier protein.
Gently mix by pipetting or slow vortexing. Allow the protein to dissolve for 15–30 minutes at room temperature with gentle agitation. If undissolved material remains, continue mixing for up to 2 hours.
Avoid vigorous shaking or foaming, which can denature the protein.
Once fully dissolved, filter sterilize if necessary (0.2 µm filter) to ensure sterility for cell culture use.
Aliquot the reconstituted protein into working volumes to avoid repeated freeze-thaw cycles, which can degrade the protein.
Storage:
Short-term (up to 1 week): 2–8 °C.
Long-term: –20 °C or –70 °C.
For long-term storage, aliquots should contain a carrier protein (e.g., 0.1% BSA) to prevent loss from adsorption and aggregation.
Dilute to final working concentration in cell culture medium immediately before use.
Summary Table: Key Steps for PTHrP Reconstitution
Step
Details
Centrifuge vial
Briefly, before opening
Reconstitution solvent
Sterile water or buffer (optionally with 0.1% BSA)
Concentration
100 µg/mL – 1 mg/mL
Mixing
Gentle pipetting or slow vortexing, 15–30 min at RT
Sterilization (if needed)
0.2 µm filter
Aliquoting
To avoid freeze-thaw cycles
Storage
2–8 °C (short-term), –20 °C/–70 °C (long-term, with carrier protein)
Working dilution
Prepare in cell culture medium just before use
Additional Notes:
Always consult the specific product datasheet for any unique requirements, as formulation and stability can vary between preparations.
Avoid buffers containing surfactants or organic solvents, as these can denature the protein or interfere with cell culture.
If using for sensitive assays, confirm endotoxin levels are suitable for your application (typically <1 EU/µg for cell culture).
These steps will help ensure maximum activity and stability of recombinant PTHrP for cell culture experiments.
References & Citations
1. Strewler, GJ. et al. (2000) New Eng J Med.342: 177 2. Stewart, AF. et al. (1998) Annu Rev Physiol.40: 431 3. Helwig, JJ. et al. (1998) Curr Opin Nephrol Hypertens.7: 27 4. Wealthall, RJ. et al. (2009) J Cell Physiol. 5. Lamberg-Allardt, C. et al. (2009) Steroids74: 277 6. Okabe, H. et al. (2008) Clin Calcium18: 489
Products are for research use only. Not for use in diagnostic or therapeutic procedures.
