Design and screening of CPP-additives with a hydrophobic
motif.
(A) Synthesized hydrophobic CPP-additives 1–10 with different hydrophobic motifs. (B) Cell viability as determined
by WST-1 mitochondrial reduction assay after treating HeLa cells with
2.5, 5, or 10 μM hydrophobic CPP-additives 1–10 for 1 h in serum-free FluoroBrite DMEM. Red dotted line indicates
100% viability. (C) Analysis of membrane integrity following CPP-additive
treatment as determined by measuring the release of LDH into the cell
medium. Data presented as mean ± standard error (SE) of three
biological replicates. (D) Rationale of the protein-CPP delivery assay.
Without CPP-additives, NLS-mCherry-R10 I enters cells
via endocytosis, while in the presence of CPP-additives, direct cytosolic
uptake should occur and the NLS-mCherry-R10 I accumulates
on the nucleolus. (E) Confocal microscopy images of cells treated
with NLS-mCherry-R10 I in the presence or absence of
indicated CPP-additives (5 μM) for 1 h in serum-free FluoroBrite
DMEM. (F) Individual nuclear fluorescence intensities of 300 cells
across three biological replicates following cotreatment with NLS-mCherry-R10
and CPP-additive. Red bar corresponds to the median fluorescence intensity
of each treatment. P-values were determined by one-way
analysis of variance (ANOVA) followed by Tukey’s post hoc analysis.
(G) Nucleolar staining in different cell lines treated with I (5 μM) and 2 (5 μM) for 1 h in
serum-free FluoroBrite DMEM. Scale bars: 20 μm.