Question

Your professor has asked you to determine the tissue specificity of a growth factor you have identified called optimusprime. Based on previous research, you know that when skin epithelial cells are treated with optimusprime, they become mesenchymal in nature. You applied optimusprime to intestinal epithelial cells and epithelial cells from the lung in culture. For some reason, optimusprime was effective in lung cells but not in intestinal cells. Your professor is convinced that you must have done something wrong because in every cell type she has tried so far, optimusprime was effective.

What are the characteristics you observe in both treated intestinal cells and lung cells?

What is one protein you could measure in your cultures to determine if optimusprime was effective? What is the function of this protein?

Provide an explanation of why optimusprime did not work in intestinal epithelial cells.

Answer 1

ANSWER 1

In the intestine, the epithelial cells are not transformed into mesenchymal cells. This indicates that the attachment between the basement membrane and the epithelial cell is maintained and intact. The cells are columnar having cilia and nucleus. The nucleus is positioned towards the basement membrane.

In the lungs, the epithelial cells are transformed into the mesenchymal cells after treatment with optimusprime. This indicates that the junction between basement membrane and epithelial cells is broken and the cells become elongated and wide with centrally placed nucleus.

ANSWER 2

Basically after expression of the mechanism of conversion of the epithelial cells to the mesenchymal cells certain transcriptional factors and growth factors will be seen.

Basically, the cells changes their polarity after treatment with optimusprime. This leads to decrease in the expression of E-cadherin which acts as cell adhesion molecules keeping the cell layer intact. Vimentin is type of structural protein that is mostly localized in mesenchymal cells and during this transition, this protein can be found in excess as its function is associated with modifying the cytoskeleton by means of microtubules. This marker expression can be checked for evaluating expression of OPTIMUSPRIME.

Another protein is the Cadherin-2 also called as N-cadherin helping in forming new cell-cell junctions by means of cell adhesion.

ANSWER 3

The function of vimentin has already been stated above and the expression rises in a step wise manner. The growth factor optimusprime interacts with E-cadherins to lower their expression levels thereby elevating the levels of metalloproteinases or follow wnt signalling pathway.

In intestinal cells the main reason for failure might be the interaction of the factor optimusprime with the cells in terms of inhibiting their E-cadherin activity thereby continuing with maintaining cell integrity. So, the levels do not decrease and the protein still maintains cell adehsion. The main effect can be seen in terms of changes in interaction between the columnar epithelia associated basal surface and the basement membrane which undergoes chemical modification by means of changes in junctions between them to disposition and delocalize the epithelial cells followed by further signalling leading to expression of other components like Vimentin, etc. Another marker used is E-cadherin whose levels can be used to check the expression of optimusprime when the activity is not progressing or promoting further cascade reaction.