lysosome

[premedrose]

There are 2 groups of lysosomal storage diseases. In Group I, there are 2 diseases, Smith syndrome and Jones syndrome, each of which is lacking a different lysosomal hydrolase, resulting in accumulation of a glycosaminoglycan within lysosomes. There is an isolated cells from patients with Smith syndrome and patients with Jones syndrome. When cells from the 2 syndromes are fused, glycosaminoglycans are now degraded properly.

In addition, surprisingly, when the medium (supernatant = solution outside of the cells) from a culture of Smith cells (“donor”) is added to a culture of Jones cells (“recipient”), the Jones defect is corrected (Jones glycosaminoglycan is now degraded).


-----Questions that I have
I don't understand how cellular fusion (in the first part) corrects the defects in the Smith and Jones cells?
What is the corrective factor (and how does it work) in the medium/supernatant? And how does the corrective factor from the Smith cells get into the Jones cell to correct the defect?

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[TieuBachHo]

I think it's due to a complimentary factor. Each of the diseases "is lacking a different lysosomal hydrolase". Therefore, when they are fused, the lysosomal hydrolases can compliment each others' deficiencies. Thus, "glycosaminoglycans are now degraded properly".

You can reason the same thing for the second question - the corrective factor. The supernatant medium may contain the missing lysosomal hydrolase of the other disease.

 

[RogueUnicorn]

I think it's due to a complimentary factor. Each of the diseases "is lacking a different lysosomal hydrolase". Therefore, when they are fused, the lysosomal hydrolases can compliment each others' deficiencies. Thus, "glycosaminoglycans are now degraded properly".

You can reason the same thing for the second question - the corrective factor. The supernatant medium may contain the missing lysosomal hydrolase of the other disease.

unlikely as it is the extracellular fluid. my guess would be that the "donor" supernatant only contains GAGs (an ECM component) the "receipient" can digest, i.e. missing the one the hydrolase for which is mutated.

edit: however, none of this seems very mcat-like

 

[TieuBachHo]

Thanks Bleargh.

 

[SN2ed]

Closed thread: Unrelated to the MCAT