Endocytic Pathway in Mouse Cardiac Cells.

Abstract

ABSTRACT. Primary cultures of heart muscle cells provide powerful tools for cardiac cell biological research that permits both physiological and biochemical approaches. In the present study we analyzed the endocytosis of cardiac cells and presented morphological characterization of the endocytic machinery using markers, which enabled us to follow the fluid-phase, receptor-mediated endocytosis and the internalization of large particles. Our results demonstrated the route of the internalized cargo to early endosomes followed or not by its discharge in the late compartments. We also confirmed the ability of cardiac muscle cells to ingest large particles such as the mannosylated ligand zymosan A, and even internalize whole eukaryotic cells such as the protozoan parasite Trypanosoma cruzi. Since endocytosis is involved in many important cellular functions, the present work contributes to the knowledge of possible additional roles played by cardiac muscle cells besides their well known ability to act as physically energetic cells in the body, constantly contracting without tiring.

RGD-containing Peptides Activate S6K1 through β3 Integrin in Adult Cardiac Muscle Cells

“…Although endocytosis is a phenomenon of almost all mammalian cells (reviewed in Ref. 51), there have been only a few reports in cardiomyocytes: fluid phase endocytosis of solutes (52), phagocytosis of yeast cells (53) and Trypanosoma cruzi (54), and clathrin-mediated endocytosis of the fluorescent marker lucifer yellow (55). In addition, there has been no report on integrin-mediated endocytosis in adult cardiomyocytes despite a few reports in other cell types: endocytosis of synthetic peptide with RGD motifs by M21 melanoma cells (39) and uptake of ECM protein-bound microbeads by retinal pigment epithelial cells that implicates integrin ␣ 5 ␤ 1 in ECM remodeling (28).…”

Endocytosis in proliferating, quiescent and terminally differentiated cells

“…Skeletal muscle fibers form large flat AP2 and clathrin lattices (Vassilopoulos et al, 2014;Liu et al, 2018), which, together with actin and α-actinin, control sarcomere maintenance, but are also endocytically active. Cardiomyocytes display active endocytosis of transferrin and integrins by means of CME, and of dextran by means of macropinocytosis (Ottesen et al, 2015;Soeiro et al, 2002;Swildens et al, 2010). They also actively internalize β1-adrenergic receptor (Morisco et al, 2008), which mostly enters cells through FEME in proliferating cells (Boucrot et al, 2015).…”

The role of endocytic pathways in cellular uptake of plasma non-transferrin iron

“…[33][34][35][36][37] The proposed mechanism explains how NTBI species bound to plasma components gain access to particular cells, but does not exclude others which comprise some plasma NTBI forms transportable by resident membrane transporters or channels. Endocytic uptake of NTBI, which is demonstrated primarily in macrophages, also operates, though to a lesser extent, in other cells such as cardiomyoblasts and cardiomyocytes ( Figure 4, Online Supplementary Figures S1-S4) and insulinoma cells (Glickstein and Cabantchik, unpublished observations, 2011).The relative contribution of NTBI endocytosis to iron accumulation in the above organs will depend on both their endocytic/pinocytic activities and on the levels of NTBI in plasma that undergoes significant modifications in chronic iron overload.…”