Fig. 3

In the presence of SIP, the levels of N-terminal HTT decrease and mutant HTT aggregates decrease. a SIP decreases the expression of proteins encoded by exon 1 of wt HTT in the cellular HD model. HEK293T cells co-transfected with plasmids that are indicated in the figure: control pEntry and e1HTT-25Q-RFP; wt SIP and e1HTT-25Q-RFP. b SIP decreases the aggregation of proteins encoded by exon 1 mHTT in the cellular HD model. HEK293T cells co-transfected with plasmids that are indicated in the figure: control pEntry and e1HTT-72Q-RFP; wt SIP and e1HTT-72Q-RFP. The left parts of panels a and b were imaged under a fluorescent microscope. Images in the right parts of panels a and b were taken under transmitted light. Scale bar = 1 µM. The size and number of mHTT aggregates (e1HTT-72Q) are presented in panels b’ and b”, respectively. Red color signals of e1HTT-72Q were measured as the number of pixels per aggregate b’ and show the average aggregate size measured for each of the analyzed images. c, d Western blot (WB) analysis of HEK293T cells that co-expressed e1HTT-25Q c or e1HTT-72Q d and wt SIP or control pEntry plasmids. c, d Graphs show densitometric analysis of western blotting bands for the indicated proteins using GAPDH abundance for normalization and presented as fold changes. M, protein marker in kilodaltons (kDa). The results are expressed as mean ± SEM. *p < 0.05, ***p < 0.001. The results were obtained from at least three independent HEK293T culture preparations