The endogenous cellular levels of UPR markers Glucose-Regulated Protein 78 (GRP78) and Activating Transcription Factor-4 (ATF-4) were evaluated in presence and absence of these osmolytes after inducing UPR with tunicamycin. As a prelude to this, IC50 values of these osmolytes were determined by using cell viability assays like MTT and Trypan Blue exclusion assay.
We found that these osmolytes in a dose-dependent manner increased the rate of restoration of homeostasis as was evident by the decreased endogenous levels of GRP78 and ATF-4.
These natural osmolytes can thus be useful in therapeutic intervention to mitigate the pathophysiological state resulting from ER-stress.