Growth Factors
Background of Growth Factors
Growth factors are a class of organic substances that are essential for regulating the normal growth and metabolism of microorganisms but cannot be synthesized de novo from simple carbon and nitrogen sources. They are multi-effect polypeptide substances that regulate cell growth and other functions by specifically and with high affinity binding to cell membrane receptors. They exist in platelets and various adult and embryonic tissues as well as most cultured cells, exhibiting a certain degree of specificity for different cell types. Typically, the growth of cultured cells requires the coordinated effects of multiple growth factors in a defined sequence. Tumor cells have the characteristic of autonomously growing independently of growth factors.
What is The Growth Factor?
Growth factors are a class of multi-effect polypeptide substances that regulate cell growth and other functions by specifically and with high affinity binding to cell membrane receptors. They are cytokines secreted by various cells and act on specific target cells to regulate cellular processes such as cell proliferation, extracellular matrix synthesis and tissue differentiation.
Growth factors control cell growth and metabolism by binding to receptors on the target cell surface and activating intracellular signaling pathways. They are produced locally and function in an autocrine or paracrine manner. Many different growth factors have been identified that exert their effects on certain cell types involved in tissues development, injury repair, and other physiological and pathological conditions. Growth factors play crucial roles in diverse biological functions through receptor-mediated intracellular signals.
Classification of Growth Factors
Table 1. Classification of Growth Factors
| Group |
|---|
| Group | Gene | Group | Gene |
|---|---|---|---|
| Bone morphogenetic proteins (BMPs) | BMP1 | Ephrins | Ephrin A1 |
| BMP2 | Ephrin A2 | ||
| BMP3 | Ephrin A3 | ||
| BMP4 | Ephrin A4 | ||
| BMP5 | Ephrin A5 | ||
| BMP6 | Ephrin B1 | ||
| BMP7 | Ephrin B2 | ||
| BMP8a | Ephrin B3 | ||
| BMP8b | Insulin-like growth factors | Insulin-like growth factor-1 (IGF-1) | |
| BMP10 | Insulin-like growth factor-2 (IGF-2) | ||
| BMP11/GDF11 | Interleukins | IL1a | |
| BMP15 | IL1b | ||
| Ciliary neurotrophic factor family | Ciliary neurotrophic factor/CNTG | IL2 | |
| Leukemia inhibitory factor /LIF | IL3 | ||
| Interleukin-6 | IL4 | ||
| Colony-stimulating factors | Macrophage colony-stimulating factor (M-CSF) | IL5 | |
| Granulocyte colony-stimulating factor (G-CSF) | IL6 | ||
| Granulocyte macrophage colony-stimulating factor (GM-CSF) | IL7 | ||
| GDNF family of ligands | Glial cell line-derived neurotrophic factor (GDNF) | Neuregulins | Neuregulin 1 (NRG1) |
| Neurturin | Neuregulin 2 (NRG2) | ||
| Persephin | Neuregulin 3 (NRG3) | ||
| Artemin | Neuregulin 4 (NRG4) |
Growth factors are widely present in various tissues of the body, including mature tissues and embryonic tissues, and regulate the proliferation and differentiation of various cells through autocrine and/or paracrine mechanisms. There are many types of growth factors, such as platelet-derived growth factors, epidermal growth factor family, fibroblast growth factors, insulin-like growth factors, nerve growth factors (NGF, Cat.No: NGF-573H), interleukin family growth factors (IL-1, Cat.No: IL1B-1167C), erythropoietin (EPO, Cat.No: EPO-578R), colony stimulating factors (CSF, Cat.No: CSF1-565H), etc. Since growth factors are secreted by normal cells, they have neither drug toxicity nor immunogenicity. Therefore, in studying their physiological mechanisms of action, some have been tested in clinical treatment. For example, interleukin-2 has been used to treat cancers, with significant effects on renal cancer and melanoma. It has also been used as an immunomodulator and in diseases related to autoimmunity. Interleukin-3 is used to treat bone marrow failure and thrombocytopenia.
Epidermal Growth Factor (EGF)
EGF has multiple biological activities. It can trigger a series of biochemical activities within cells and strongly promotes cell proliferation and enhances cell activity. It stimulates epithelial and epidermal cells and promotes epidermal growth and keratinization. It promotes metabolism, accelerates the synthesis of hyaluronic acid and glycoproteins, and promotes wound healing of skin and mucous membranes. It has wide applications in treating burns, scalds, surgical wounds, mechanical injuries, skin ulcers, laser beauty, etc. to protect skin and mucous membranes from or reduce mechanical and chemical damage.
Fibroblast Growth Factor (FGF)
FGF is ubiquitous in mammals and is a heparin-binding mitogenic protein that induces proliferation and differentiation of various cell types and has important functions in the nervous system.
Keratinocyte Growth Factor-2 (KGF-2)
KGF is an alkaline protein growth factor secreted by subcutaneous tissue cells in the human body, composed of 40 amino acids and with a molecular weight of approximately 24 kDa. KGF-2 promotes proliferation of keratinocytes in the upper layer, stimulates regeneration, differentiation and migration of epidermal cells around injured tissues, and accelerates wound healing.
Vascular Endothelial Growth Factor (VEGF)
VEGF is a highly specific mitogen of vascular endothelial cells, located on the surface of vascular endothelial cells. It is an angiogenic regulatory factor that promotes endothelial cell proliferation, promotes blood vessel formation, and increases vascular permeability.
Bone morphogenetic proteins (BMPs)
Bone morphogenetic proteins (BMPs) are a group of growth factors also known as cytokines and as metabologens. Originally discovered by their ability to induce the formation of bone and cartilage, BMPs are now considered to constitute a group of pivotal morphogenetic signals, orchestrating tissue architecture throughout the body. The important functioning of BMP signals in physiology is emphasized by the multitude of roles for dysregulated BMP signaling in pathological processes.
Interleukins
Interleukins are a group of cytokines (secreted proteins and signal molecules) that were first seen to be expressed by white blood cells (leukocytes). They are responsible for communication between cells during inflammatory responses and throughout an immune response. They help the immune system regulate the production of other cells and antibodies to fight off infections or diseases. Currently, there are about 40 different types of interleukins identified.
What are the Applications of Growth Factors?
Growth factors are biologically active proteins or polypeptide substances that have wide regulatory effects on the growth and development of organisms within biological systems. In general, they are capable of specifically binding to cell membrane receptors and have effects in regulating cell growth and development. They play important regulatory roles in immune functions, hematopoiesis regulation, tumorigenesis, inflammation and infection, wound healing, angiogenesis, cell differentiation, cell apoptosis, morphogenesis, embryogenesis and other aspects of the human body.
By binding to cell surface receptors, growth factors initiate intracellular signal transduction pathways and regulate a variety of cellular processes including proliferation, differentiation and survival. They function through autocrine or paracrine modes of action. Growth factors maintain tissue homeostasis and precisely coordinate complex programs of cell behavior during development, wound repair, and other physiological phenomena. Their regulatory effects are crucial for normal growth, development and function of living organisms.
- Wound Healing: Growth factors are often used to enhance the healing process of wounds. They can accelerate the process by stimulating cell proliferation and differentiation.
- Tissue Engineering: Growth factors have a significant role in tissue engineering and regenerative medicine. They are used to create new tissues that can replace injured or diseased body parts.
- Treatment of Various Diseases: Growth factors can be used in the treatment of different types of diseases such as cancer, anemia, and macular degeneration. They are used to stimulate the growth of specific types of cells in these diseases.
- Bone and Cartilage Repair: Growth factors like bone morphogenic proteins (BMPs) and transforming growth factor beta (TGF-β) play a vital role in bone and cartilage repair. They promote the formation of new bone and cartilage tissues.
- Skin Care Products: Several skincare products contain growth factors. They can help to rejuvenate the skin by stimulating the production of collagen and elastin, which are responsible for maintaining the skin's elasticity and firmness.
- Hair Loss Treatment: Some hair loss treatments use growth factors to stimulate the growth of hair follicles.
- Stem Cell Research: Growth factors are used to control the differentiation and proliferation of stem cells in research settings.
- Enhance Athletic Performance: While controversial and often against regulations, some athletes have used growth factors in an attempt to enhance physical performance, speed up recovery time after injuries, or increase muscle mass.
- Dental Treatments: Growth factors are also applied in dental treatments to enhance the healing process after tooth extractions, surgery, or to treat periodontal disease.
- Nerve Regeneration: Certain growth factors promote nerve regeneration in patients with nerve damage or neurological conditions.
Case Study
Case 1: Reihlen, P., Blobel, M., Weiß, P., et al. Introduction of a PEGylated EPO conjugate as internal standard for EPO analysis in doping controls. Drug Testing and Analysis. https://doi.org/10.1002/dta.3211
Immunopurification of doping control samples is a mandatory necessity in erythropoietin (EPO) analysis during a confirmation procedure; moreover, it has become common practice to also immunopurify samples for the initial testing procedure. The presented data demonstrate that a 12-kDa PEG residue attached to human EPO represents a particularly useful construct to serve as ISTD for erythropoietin-receptor agonist (ERA) analysis. The conjugate is applicable to both urine and blood testing using the commonly employed purification techniques, supporting and improving result interpretations especially concerning specimens where the natural abundance of human EPO is low.
Fig1. (a) Immunoblot after sodium N-lauroylsarcosinate (“sarcosyl”) polyacrylamide gel electrophoresis (SAR-PAGE) of urine samples spiked with different Recombinant erythropoietin-polyethylene glycol (rEPO-PEG) conjugates. rEPO was conjugated with PEGs of varying molecular mass via aldehyde (Ald) or N-hydroxysuccinimide ester (NHS) linkage: 5-kDa Ald (1), 10-kDa Ald (2), 20-kDa Ald (3), ESA-Mix CERA-NESP-Dynepo (4), ESA-Mix EPO Fc-NESP-Dynepo (5), 5-kDa NHS (6), 10-kDa NHS (7), and 20-kDa NHS (8). (b) Immunoblot after SAR-PAGE of different directly applied rEPO-PEG conjugates. ESA-Mix EPO Fc-NESP-Dynepo (1), ESA-Mix CERA-NESP-Dynepo (2), 12-kDa NHS (3), 40-kDa Ald (4), and 60-kDa Ald (5)
Case 2: Patel, J. J., Modes, J. E., Flanagan, C. L., et al. (2015). Dual Delivery of EPO and BMP2 from a Novel Modular Poly-ɛ-Caprolactone Construct to Increase the Bone Formation in Prefabricated Bone Flaps. Tissue Engineering. Part C, Methods, 21(9), 889-897. https://doi.org/10.1089/ten.tec.2014.0643
Poly-ɛ-caprolactone (PCL) is a biocompatible polymer that has mechanical properties suitable for bone tissue engineering; however, it must be integrated with biologics to stimulate bone formation. Bone morphogenetic protein-2 (BMP2) delivered from PCL produces bone when implanted subcutaneously, and erythropoietin (EPO) works synergistically with BMP2. In this study, EPO and BMP2 are adsorbed separately on two 3D-printed PCL scaffold modules that are assembled for codelivery on a single scaffold structure. BMP2 and EPO scaffolds had more ingrowth (1.4%±0.6%) in the outer module when compared with BMP2 (0.8%±0.3%) at 4 weeks. Dual delivery produced more dense cellular marrow, while BMP2 had more fatty marrow. Dual EPO and BMP2 delivery is a potential method to regenerate bone faster for prefabricated flaps.
Fig1. Modular scaffold assembly. BMP2 was adsorbed onto the inner scaffold module and EPO was adsorbed onto the outer scaffold module. The two scaffolds were then assembled. BMP2, bone morphogenetic protein-2; EPO, erythropoietin.
Case 3: Playne R, Jones K, Connor B. Generation of dopamine neuronal-like cells from induced neural precursors derived from adult human cells by non-viral expression of lineage factors. J Stem Cells Regen Med. 2018 May 30;14(1):34-44. doi: 10.46582/jsrm.1401005. PMID: 30018471; PMCID: PMC6043657.
Reprogramming technology holds great promise for the study and treatment of Parkinson's disease (PD) as patient-specific ventral midbrain dopamine (vmDA) neurons can be generated. This should facilitate the investigation of early changes occurring during PD pathogenesis, permitting the identification of new drug targets and providing a platform for drug screening.
Previous reports have indicated that induced neural precursors (iNPs) derived from adult human fibroblasts by lineage factor-mediated direct reprogramming can give rise to dopamine neurons expressing tyrosine hydroxylase (TH+). Using normal adult human fibroblasts, the present study aimed to extend these findings and determine the capacity of iNPs for generating vmDA neurons, with the aim of utilising this technology for the future study of PD.
Fig1. Expression of dopaminergic markers in cultures differentiated with Patterning and Maturation media. Arrowheads indicate cells with positive staining.
FAQs
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Q: What’s the Differences between Growth Factors and Cytokines?
A: Growth factors and cytokines are both types of signaling molecules used by the body to communicate between cells. Growth factor is sometimes used interchangeably among scientists with the term cytokine. They often have similar functions, but there are several differences:
Specificity: Growth factors generally have a more specific target audience than cytokines. Their main function is to promote the growth, differentiation, and survival of specific cell types, primarily in the context of tissue growth and repair. On the other hand, cytokines have broader targets and actions. They can act on many different types of cells and have diverse functions, including inflammation, immune responses, cell proliferation and differentiation.
Origin: Growth factors can be produced by most types of cells, but are primarily produced by platelets and endothelial cells. Cytokines, on the other hand, are mostly produced by cells of the immune system, such as T cells, macrophages, and dendritic cells.
Function: Growth factors mainly stimulate cell growth, proliferation and differentiation, thus playing a crucial role in angiogenesis, wound healing, and the maintenance of cellular homeostasis. Cytokines are typically associated with inflammation and immune responses. They can stimulate cell growth and differentiation, but they can also inhibit these processes.
Structure: Cytokines and growth factors can also differ in their structure. For instance, cytokines are generally smaller and less complex than growth factors. -
Q: Are all the growth factor products listed in the table?
A: No, the table has collected some products that have been sorted and summarized so far. There may be some products that have not been included, and we will continue to supplement them.
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Q: How could I do if I don't find the product I need in the list?
A: If you don’t find you desired protein in the product list, you could search the protein in the search bar on the top of the website. If you still don’t find the product, or you have a special requirements for the protein, just inquiry us directly.
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Q: What applications can the purchased protein be used for?
A: The specific situation of each protein product is different. Please judge according to the product datasheet or inquiry us directly.
