Approaches for plasma membrane wounding and assessment of lysosome-mediated repair responses

Abstract

Rapid plasma membrane repair is essential to restore cellular homeostasis and improve cell survival after injury. Several mechanisms for plasma membrane repair have been proposed, including formation of an intracellular vesicle patch, reduction of plasma membrane tension, lesion removal by endocytosis, and/or shedding of the wounded membrane. Under all conditions studied to date, plasma membrane repair is strictly dependent on the entry of calcium into cells, from the extracellular medium. Calcium-dependent exocytosis of lysosomes is an important early step in the plasma membrane repair process, and defects in plasma membrane repair have been observed in cells carrying mutations responsible for serious lysosomal diseases, such as Chediak–Higashi (Huynh, Roth, Ward, Kaplan, & Andrews, 2004) and Niemann–Pick Disease type A (Tam et al., 2010). A functional role for release of the lysosomal enzyme acid sphingomyelinase, which generates ceramide on the cell surface and triggers endocytosis, has been described (Corrotte et al., 2013; Tam et al., 2010). Therefore, procedures for measuring the extent of lysosomal fusion with the plasma membrane of wounded cells are important indicators of the cellular repair response. The importance of carefully selecting the methodology for experimental plasma membrane injury, in order not to adversely impact the membrane repair machinery, is becoming increasingly apparent. Here, we describe physiologically relevant methods to induce different types of cellular wounds, and sensitive assays to measure the ability of cells to secrete lysosomes and reseal their plasma membrane.

Schwann cell dedifferentiation-associated demyelination leads to exocytotic myelin clearance in inflammatory segmental demyelination

“…It was previously shown that SC autophagolysosomes are involved in myelin fragmentation into small clumps during WD (Jang et al, ), which may indicate an essential role of autophagy in membrane remodeling because membrane fusion and repair between the different myelin lamella should be accompanied to complete myelin fragmentation within a SC. It has been shown that lysosomal membranes are able to fuse with the membranes of other organelles including the plasma membrane to regulate exocytosis and membrane repair (Corrotte et al, ; Medina et al, ; Reddy, Caler, & Andrews, ). In addition, recent studies have shown the role of autophagy in these two processes (Feeney et al, ).…”

The conceptual introduction of the “demyelinating Schwann cell” in peripheral demyelinating neuropathies

“…This suggests that SCs could activate the machinery for membrane remodeling during WD. Lysosomes, which play an essential role in plasma membrane remodeling and repair (Corrotte, Castro-Gomes, Koushik, & Andrews, 2015;Reddy, Caler, & Andrews, 2001), may also be involved in this process. Indeed, lysosomal exocytosis, a mechanism of plasma membrane repair, was reported to participate in peripheral nerve repair (Chen et al, 2012).…”

“…Therefore, the expulsion of myelins containing axonal debris to the abaxonal extracellular space can be considered as myelin debris transcytosis (Figure 2). Lysosomes, which play an essential role in plasma membrane remodeling and repair(Corrotte, Castro-Gomes, Koushik, & Andrews, 2015;Reddy, Caler, & Andrews, 2001), may also be involved in this process. Even though the molecular mechanisms of this process are still largely unknown, various membranous structures observed in the cytoplasm of DSCs such as autophagosomes, endosomes, expanded endoplasmic reticulum, multivesicular bodies, and primary lysosomes could be implicated in the transcytotic myelin clearance (Brosius Lutz et al, 2017; Gomez-Sanchez et al, 2015; Holtzman & Novikoff, 1965).Large clumps of myelin that contain the degenerated axon in their centre are also often observed in the extracellular space in the late stage of WD(Beuche & Friede, 1984;Goodrum & Bouldin, 1996;Jang et al, 2017;Ohara, Takahashi, & Ikuta, 1986;Stoll et al, 1989; Figures 2 and 3), and they can be clearly visualized following abrogation of macrophage infiltration as the rejected myelin would be rapidly removed by macrophages(Beuche & Friede, 1984;Goodrum & Bouldin, 1996;Jang et al, 2017; Figure 3).…”

Massive surface membrane expansion without involvement of classical exocytic mechanisms

“…It has long been known that diverse cell types can expand their PM by substantial amounts in response to large elevations of cytoplasmic Ca 2+ (Coorssen et al, 1996;Ninomiya et al, 1996;Kasai et al, 1999;Togo et al, 2003;Kreft et al, 2004;Bretscher, 2008;Cohen et al, 2008;Yaradanakul et al, 2008). This expansion has often been suggested to mediate repair of membrane wounds (Togo et al, 2003;Bradke et al, 2012;Cooper and McNeil, 2015;Corrotte et al, 2015), and an involvement of SNARE-mediated mechanisms seems well established in some cell wounding protocols (Bi et al, 1995). In a companion article (Bricogne, XXXX), we have shown that TMEM16F can initiate large-scale PM expansion in multiple cell types.…”

“…In brief, the PM is continuously modified by discrete membrane fusion and excision events that transfer chemicals to and from the extracellular space and modify the protein content of the PM (Sudhof and Rothman, 2009). Beyond the transport of chemicals and membrane proteins, PM expansion can become essential for cell growth (Tojima et al, 2014), to allow cell swelling (Groulx et al, 2006), to repair PM wounds (Togo et al, 1999;Cooper and McNeil, 2015;Corrotte et al, 2015;Moe et al, 2015), to relax membrane tension caused by chronic stretch, e.g. bladder extension (Lewis and de Moura, 1984), and to execute multiple steps of fertilization in mammals (Gadella and Evans, 2011).…”