Gap junction connexin43 is a key element in mediating phagocytosis activity in human trabecular meshwork cells

Human trabecular meshwork (TM) cells play pivotal roles in maintaining homeostasis of intraocular pressure via regulation of aqueous humor outflow. These cells are capable of phagocytosis, which is considered to be essential for their regulatory function. In addition, there is a strong expression of the gap junction protein connexin43 (Cx43) in the TM. Here, we investigated functional relationships between phagocytosis activity of TM cells and their expression of Cx43. Phagocytosis was measured by showing the ability of TM cells to engulf inert fluorescent particles consisting of pHrodo. We found that internalized pHrodo was partially co-localized with Cx43 and that the phagocytic activity was dramatically reduced after knockdown of Cx43 using lentiviral Cx43 shRNA. These results suggest that Cx43 is involved in the regulation of phagocytosis by TM cells.