Cell Mechanics Regulate Membrane Tubulation-Driven Trogocytosis in Adherent Cells

Trogocytosis is a widespread and physiologically important process in which one cell ingests fragments of another. It has been observed in diverse biological contexts, such as in Entamoeba histolytica, a human enteric parasite that nibbles host intestinal cells via trogocytosis, thereby invading the tissue and leading to lethal extra-intestinal disease, and in macrophages on interaction with adherent tumor monolayers. Despite its physiological relevance, knowledge of trogocytosis with adherent cells remains elusive. Here, we established a monolayer-based trogocytosis assay and uncovered a distinct membrane-tube-mediated trogocytic mechanism operative in adherent cells. We characterized it into four sequential events: contact, membrane tubulation, stretching, and scission. By targeting the proteic constituents of target cell stiffness, we show that trogocytic output exhibits a non-monotonic dependence on the viscoelastic properties of the target cell, with maximal uptake occurring in an intermediate mechanical regime. Further, we integrated live-cell trogocytosis observations with a viscoelastic model-based theoretical framework to propose a tube-breaking mechanism across distinct mechanical subtypes. Finally, using micropatterning, we demonstrated that target cell shape influences trogocytosis kinetics. This work suggests that trogocytosis is sensitive to the mechanical state of the target cell.