Cells communication following the implantation

When cells touch the stent, there are a lot of physical and chemical reactions happen. Immediately after a tissue engineering scaffold is implanted into an organism or comes into contact with cell culture environments, protein adsorption to its surface occurs and which mediates the cell adhesion, and also provides signals to the cell through the cell adhesion receptors, mainly integrins. (Chang & Wang, 2011) For communication, two the most important factors are cell signalling molecular and cell receptors. So we are going to discuss about cell signalling molecular firstly. Signal transduction, in fact can be imagined in our brains, like a soldier brings information to come to command centre, and the receptor is the guard of centre for defending, receptor transmit the information to cell and give responses. All processes indicate in the below figure 4. And during the process 2, the transmission inside cells of a molecules chain is known as intracellular signal transduction pathways.

Figure 4. The process of cell signalling. (Signal transduction pathway | cell signaling (article) 2022) PS. Signalling molecules are often called ligands.

Signalling molecules are various, mainly are proteins but also include some non-protein molecules like amino acids, nucleotides, phospholipids and so on, different types of molecules may have very different effects and lifespan.

The other one, the receptor, obviously receives the signal. However, not any receptor can receive signals, and the cell must have the correct receptor for the signals.

There are 3 main receptors types:

Ion-channel-coupled receptors: ions enter into inside through plasma membrane as signal molecule.

G-protein-coupled receptors: a signal molecule activates the receptor and following activates receptor, finally lead signalling molecule to a response.

Enzyme-coupled receptor: there is an inactive catalytic domain will be formed with signal molecule then be activated, and there are many others rely on associated enzymes to lead the processes as well.

Figure 5. Three classes of cell-surface receptors. (Signal transduction- the process of converting a signal from outside the cell to a functional change within the cell Scott Wilson Department of Neurobiology.)

Now let’s get to the most important, signalling.

There are 4 ways to signal in multicellular organisms, autocrine, paracrine, endocrine and contact dependent respectively. Figure 6, 7 and 8 given below let us understand easily.

Figure 6. (Cell signaling | biology library | science)

Figure7. (Cell signaling | biology library | science)

Figure8. (Cell signaling | biology library | science)

Autocrine, cells send signals to themselves, the way cells transmit signals within a short distance called paracrine, and neurotransmitter system is a classic example. Neuronal discharges are nerve impulses, electrical impulses that travel via the axon to the synapse in cell and neurotransmitters (ligands) will be released, which is a completely process about the transmission of information, then relatively chemical reactions happen inside cells. For a far distance, endocrine is the main way for signal transmission, signals are released by cells and transmitted within bloodstream to destination, the whole process finished by the circulatory system, and these signals called hormones. Hormones play an important role in human physiology and growth. Human organs that release hormones include the thyroid gland, hypothalamus, pituitary gland, gonad and pancreas. For contact dependent, just for small molecules, large molecules like proteins cannot be transmitted via this way.

Figure 9. (Cell signaling | biology library | science)