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Human mesenchymal stem9d0u/ e1j0.e hzspw e;:k4l;bcv vjex cells (Mq x t*a0c 0ojcz io tcn-e*g36l4mkdo.o3xv,4SCs) are found in a variety of tissues, such as the bone marrow and adipose tissue. Due to their multipotency, MCSs can differvqoo44kn-0*g c303*cdoj ex. i ltc6 t,maoxzentiate into a number of different types of cell.
Recent studies have suggested that changes in metabolism are vitally important during the process of cell differentiation. In one such study, scientists investigated the changes which occur to the mitochondria in MSCs during the process of differentiation into adipogenic cells, which are cells of the adipose tissue, an important energy storage site in the body.
To begin the investigation, scientists had to stimulate the differentiation of MSCs into adipogenic cells. Differentiation of MSCs was confirmed with the use of both Oil Red O staining and RT-PCR, which demonstrated the relative expression of adiponectin mRNA, which is a key indicator of adipogenic differentiation.
1. 1.Calculate how many times greater the expression of adiponectin is in adipogenic cells after 21 days, compared to 7 days.
2.Predict the relative expression of adiponectin mRNA after 14 days. `
In their next experiment, scientists stained mitochondria in undifferentiated MSCs and differentiated adipogenic cells after 7 days, using MitoTracker Green stains, and then using flow cytometry, recorded fluorescence as a measure of mitochondrial mass.
2. 1.Suggest why there is an increase in mitochondrial mass in adipogenic cells after 7 days compared to MSCs.
2.Calculate, as a percentage, the increase in mean fluorescent intensity in adipogenic cells after 7 days compared to MSCs. %
In their penultimate experiment, scientists measured the TOM20 protein levels of the outer mitochondrial membrane.
3.Compare and contrast the results obtained from the measurement of mitochondrial mass using flow cytometry and protein levels.
In their final experiment, scientists measured the mitochondrial oxygen consumption rate and lactate production in both MSCs and adipogenic cells.
4. 1.Outline the effect of differentiation on the rate of oxygen consumption and lactate production.
2.Suggest a reason for the change in oxygen consumption rate in adipogenic cells from day 1 to 7.
3.Explain, with reference to respiration, the change in lactate production in adipogenic cells.
5.Explain how the results obtained from these experiments on mitochondria can be used to understand metabolic changes during differentiation.
6.Using all the data provided, evaluate the hypothesis that the rate of respiration increases during cell differentiation
