A novel form of cellular communication among thymic epithelial cells: intercellular calcium wave propagation

Abstract

We here describe intercellular calcium waves as a novel form of cellular communication among thymic epithelial cells. We first characterized the mechanical induction of intercellular calcium waves in different thymic epithelial cell preparations: cortical 1-4C18 and medullary 3-10 thymic epithelial cell lines and primary cultures of thymic "nurse" cells. All thymic epithelial preparations responded with intercellular calcium wave propagation after mechanical stimulation. In general, the propagation efficacy of intercellular calcium waves in these cells was high, reaching 80-100% of the cells within a given confocal microscopic field, with a mean velocity of 6-10 microm/s and mean amplitude of 1.4- to 1.7-fold the basal calcium level. As evaluated by heptanol and suramin treatment, our results suggest the participation of both gap junctions and P2 receptors in the propagation of intercellular calcium waves in thymic nurse cells and the more prominent participation of gap junctions in thymic epithelial cell lines. Finally, in cocultures, the transmission of intercellular calcium wave was not observed between the mechanically stimulated thymic epithelial cell and adherent thymocytes, suggesting that intercellular calcium wave propagation is limited to thymic epithelial cells and does not affect the neighboring thymocytes. In conclusion, these data describe for the first time intercellular calcium waves in thymic epithelial cells and the participation of both gap junctions and P2 receptors in their propagation.

Modulatory effects of cAMP and PKC activation on gap junctional intercellular communication among thymic epithelial cells

“…Confirming previous results from our Laboratory [39,61,62] flow cytometry experiments revealed that after 6 hours of co-culture more than 65% of the initial single positive DiIc 18 (3) + TEC acquired calcein (Figure 1B). To ascertain that gap junctions mediated this dye transfer we treated the cells for 6 hrs with 100 μM of 18-β-glycyrrhetinic acid (GRA), a gap junction inhibitor.…”

Intercellular Ca2+Waves: Mechanisms and Function

“…Subsequently, ICWs have been found to be initiated by a variety of stimuli in a diversity of cell types, including glial cells (246,312,361), neurons (56, 153), various epithelial (171,249) and endothelial (47,129,382) cells, smooth muscle cells (151, 407), cardiomyocytes (352), hepatocytes (122), osteocytes (178), chondrocytes (189), kidney cells (276,402), mammary gland cells (104), mast cells (255), pancreatic acinar cells (409), and keratinocytes (188). FIGURE 1 illustrates typical examples of ICWs in glial and endothelial cells.…”

Gap junction-mediated antigen transport in immune responses

“…Several studies have indicated the involvement of gap junctions in the communication between cells of the immune system [17][18][19][20][21][22][23][24]. Indirect evidence for the importance of gap junctions in immunity comes from the observation that viruses -such as herpes simplex virus (HSV) and human papillomavirus (HPV) -actively influence gap junction communication [25][26][27][28].…”