MODULATING THE INTERNALIZATION OF CELL PENETRATING PEPTIDES INTO HUMAN SPERMS AND DENDRITIC CELLS

M. VICTORIA BERBERIAN; IGNACIO CEBRIAN; LUIS S. MAYORGA

Buenos Aires

Congreso; Reunion conjunta de sociedades de biociencias; 2017

MODULATING THE INTERNALIZATION OF CELL PENETRATING PEPTIDES INTO HUMAN SPERMS AND DENDRITIC CELLSThe development of tools that facilitate the cellular uptake of therapeutic molecules constitutes an active field of research. Cell penetrating peptides (CPPs) have been introduced as novel biocarriers, since they are able to translocate cell membranes by a mechanism which is still poorly understood. Experimental evidence suggests that CPPs internalization may occur by physical diffusion across cell membranes, may involve endocytic processes, or a combination of both. In this work, we explore the conditions that optimize the translocation of CPPs into human sperms and dendritic cells (DCs). We combine fluorescence microscopy and flow cytometry to analyze the effect of membrane potential, pH of the extracellular medium, and cell membrane composition, on the internalization of the TAT peptide. Ours results show that DCs internalize TAT via endocytic and diffusive pathways, while only the diffusive mechanism operates in sperms. Moreover, in both cases the kinetics of TAT translocation depends on the membrane potential at short times (5 min). For example, when cell membranes are hyperpolarized, TAT enters at higher rates, and in more cells (90%), in comparison with a control sample (50%). In contrast, when the cell membrane is depolarized, we observe a significant decrease, both in translocation rate and in the number of cells that show TAT in the cytosol (20%). Regarding the effect of pH, DCs incorporate TAT more quickly and effectively at alkaline pHs, whereas the translocation in sperms is unaffected by changes in pH. In conclusion, we have demonstrated that TAT translocates the cell membrane of sperms and DCs after co-incubation for a few minutes, and that the translocation efficiency can be modulated by varying some simple experimental parameters.Keywords: cell penetranting peptides, sperms, dendritic cells, cell membranes.