Modulating the internalization of cell penetrating peptides into human sperms and dendritic cells

MAYORGA, LS; CEBRIAN, I; BERBERIAN MV

Buenos Aires

Congreso; Reunión Conjunta Sociedades Biociencias; 2017

SAIB

The development of tools that facilitate the cellular uptake of therapeuticmolecules constitutes an active field of research. Cell penetratingpeptides (CPPs) have been introduced as novel biocarriers,since they are able to translocate cell membranes by a mechanismwhich is still poorly understood. Experimental evidence suggeststhat CPPs internalization may occur by physical diffusion across cellmembranes, may involve endocytic processes, or a combination ofboth. In this work, we explore the conditions that optimize the translocationof CPPs into human sperms and dendritic cells (DCs). Wecombine fluorescence microscopy and flow cytometry to analyzethe effect of membrane potential, pH of the extracellular medium,and cell membrane composition, on the internalization of the TATpeptide. Ours results show that DCs internalize TAT via endocyticand diffusive pathways, while only the diffusive mechanism operatesin sperms. Moreover, in both cases the kinetics of TAT translocationdepends on the membrane potential at short times (5 min). Forexample, when cell membranes are hyperpolarized, TAT enters athigher rates, and in more cells (90%), in comparison with a controlsample (50%). In contrast, when the cell membrane is depolarized,we observe a significant decrease, both in translocation rate and inthe number of cells that show TAT in the cytosol (20%). Regardingthe effect of pH, DCs incorporate TAT more quickly and effectively