Comparing the effectiveness of TAT and myristoylation of gp91ds on leukocyte superoxide (SO) release

Philadelphia

It is well known that adding myristic acid or transactivating (TAT)carrier peptide to native peptides will facilitate cell membranepermeability required for targeting intracellular substrates. However, it is not known if differences exist in the effectiveness of myristic acid versus TAT conjugated peptides. To test this, we compared the dose-response relationship of myristoylated (Myr-peg linker-C-S-TR-I-R-R-Q-L-NH2oxidase assembly inhibitor (gp91ds), ([H]-R-K-K-R-R-Q-R-R-R- CS-T-R-I-R-R-Q-L-NH2gp91ds with glycine-glycine spacer in between TAT and gp91ds (MW=2566 g/mol) on N-Formyl-L-Methionyl-L-Leucyl-L-Phenylalanine (fMLP) induced leukocyte superoxide (SO) release.Myr-peg-gp91ds NADPH oxidase peptide inhibitor significantly attenuated fMLP-induced leukocyte SO release dose dependently (40±11%; 2 μM; n=13), (53±8%; 5μM; n=13), and (64±8%;10μM; n=11, p<0.01) compared to fMLP (1μM; n= 29; change in absorbance 0.196±0.012 from baseline) or native sequence which inhibited the fMLP response by only 11±4% at the highest dose tested (80μM; n=10). The TAT gp91ds inhibitors (both 80μM; n=13, p<0.05) significantly attenuated fMLP-induced leukocyte SO release by 35±11%, but to a lesser extent than the myr-peg linked inhibitor. These results suggest that myr-peg-gp91ds is more cell permeable and therefore can inhibit fMLP-induced SO release from leukocytes at lower doses compared to TAT gp91ds.; MW=1486 g/mol) and TAT conjugated NADPH ; MW=2452 g/mol) or TAT conjugated.