Polarized localization of subcellular components in peritubular myoid cells

IBAÑEZ J; LUIS A LÓPEZ; FERNANDA MF

CABA

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

SAIC

POLARIZED LOCALIZATION OF SUBCELLULAR COMPONENTS IN PERITUBULAR MYOID CELLSMarra MF, Ibañez JE, Lopez L A. IHEM UNCuyo- CCT-Conicet Mendoza, 5500 Mendoza. In rat testes, peritubular myoid cells (PM cells) form the outer monolayer of the seminiferous tubule (ST). PM cells have characteristics of smooth muscle cells and participate in ST contraction. The study of MP cells has been carried out in crushed TS, so the 3D shape and distribution of cellular components are unknown. The objective of this work was to construct a 3D model of MP cells and determine microfilaments, lipid microdomains and caveolae location using optical planes (OP) (36-40 cross sections of 0.4 μm). To achieve this objective, subcellular structures of the MP cells (alpha-actin filaments, plasma membrane, nucleus, lipid microdomains and caveolae) were identified by immunofluorescence. The OP were processed with Image-J sofware. 3D reconstruction of the OP allowed us to determine that MP cells has an irregular hexagon shape with a cleft in its apical face. Remarkably, MP cell has marked apical-basal polarization. In the apical face, most of actin filaments were distributed longitudinally (LF) (71% ± 0.9) and a few ones transversally (TF) (29% ± 0.9). In the basal face TF were the majority (72% ± 2.2) and LF (28% ± 2.2). In other hands, caveolae (identified with anti-caveolin-1), were located following actin filaments distribution. They are identified as isolated dots arranged in longitudinal lines (LL) or transversal lines (TL). In the apical face most of caveolae are in LL ( n=9) in a number of 58 ± 1.5 dots/line. and in a few TL (n=5) in a number of 25 ± 1.5 dots/field. In the basal face most of caveolae are in TL ( n=10) in a number of 60 ± 2.5 dots/line. and in a few LL (n=6) in a number of 28 ± 1.2 dots/line. Also the lipid microdomains are distributed throughout the cell surface, but show a higher concentration on the basal surface. These results indicate that MP cells are organized in an apical-basal polarity similarly to epithelial cells. The question is ¿Are MP cells in contact with two different environments?