Research

Growth Factor

►an overview

Growth factors are a class of hormone-like signaling molecules secreted by cells, most of them are peptides, which can regulate cell growth and differentiation. There are dozens of peptide growth factors, which can come from many different tissues and target cells.

►Classification
There are many kinds of growth factors, which can be classified into transforming growth factor-beta, nerve growth factor, epidermal growth factor, fibroblast growth factor, vascular endothelial growth factor and so on. Transforming growth factor (TGF) plays an important role in immune regulation. Many cells in vivo can secrete inactive TGF, which can be activated by acid or some enzymes.

►Mode of action
According to the relationship between the cells that produce growth factors and the cells that receive growth factors, the ways of producing growth factors can be summarized as the following three patterns.

1. Endocrinology
Growth factor secreted from the cell and transported through the blood to distant target cells.

2. paracrine
When the growth factor is secreted from the cells, it acts on other adjacent types of cells, and does not act on its own cells because of the lack of corresponding receptors in its own cells.

3. autocrine
Growth factors act on the cells that synthesize and secrete this growth factor. Growth factors are the two main modes of action.

► Mechanism of action
1. membrane receptor
Membrane receptors of some growth factors are transmembrane receptor proteins. Some of them have tyrosine kinase activity in their cells and play the role of growth factors through the receptor tyrosine protein kinase pathway. In addition, membrane receptors of some growth factors play the role of growth factors by producing a second messenger through the cellular messaging system.

2. intracellular receptors
Some growth factor receptors are located in the cells, along the intracellular receptor signaling pathway, activate related genes, promote cell growth.

►Growth factor function
The function of growth factor is mainly to promote cell growth, differentiation, and promote the development of individuals. The same growth factor has different effects on different cells, and one cell can also be regulated by different growth factors. Most of the growth factors have the function of promoting the growth of target cells, a few have the function of negative regulation, and some have the function of both positive and negative regulation.

►growth factors and diseases
1. growth factor and tumor
In addition to the abnormal activation of oncogenes and the abnormal inactivation of tumor suppressor genes, tumorigenesis is also closely related to the high activation of growth factors and their receptors. Overexpression of epidermal growth factor, vascular endothelial growth factor and nerve growth factor can lead to the corresponding tumorigenesis.

2. growth factors and cardiovascular diseases
(1) Essential hypertension is closely related to oncogene. The cytological changes of hypertension are the proliferation of vascular smooth muscle cells and fibroblasts, which increases the peripheral vascular resistance.
(2) A large number of oncogenes are overexpressed in myocardial hypertrophy, and the role of growth factors in myocardial hypertrophy is very important.

cell signal
cytokine
paracrine signal
growth factor

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