Leukocyte transmigration requires kinesin-mediated microtubule-dependent membrane trafficking from the lateral border recycling compartment

Abstract

Diapedesis of leukocytes across endothelial cells is a crucial step in both the innate and adaptive immune responses. Surface molecules on leukocytes and endothelial cells critical for diapedesis have been identified, but the mechanisms underlying this process are not understood. Homophilic interaction between platelet/endothelial cell adhesion molecule (PECAM) on leukocytes and PECAM at the endothelial border triggers targeted recycling of membrane from a reticulum localized close to the endothelial cell lateral border. This membrane surrounds the transmigrating leukocyte (Mamdouh, Z., X. Chen, L.M. Pierini, F.R. Maxfield, and W.A. Muller. 2003. Nature. 421:748–753). How this process occurs and whether it is required for diapedesis independent of PECAM are not known. We now report that targeted recycling from this lateral border recycling compartment (LBRC) is required for diapedesis, is mediated by kinesin family molecular motors, and requires normally functioning endothelial microtubules. Selective disruption of microtubules or inhibition of kinesin motor domain blocked targeted recycling and diapedesis of monocytes. Furthermore, targeted recycling of membrane from the LBRC was required for transmigration of lymphocytes, which migrate independently of PECAM. Thus, trafficking of membrane from the LBRC to surround leukocytes may be a general requirement for migration of leukocytes across the endothelial cell border. Furthermore, these data provide the first demonstration of a role for endothelial microtubules and kinesins in promoting diapedesis, and a mechanism to explain targeted recycling.

TRPC6 is the endothelial calcium channel that regulates leukocyte transendothelial migration during the inflammatory response

“…Targeted recycling assays were performed as previously described (Mamdouh et al, 2003(Mamdouh et al, , 2008). In brief, HUVEC monolayers were grown to confluency on hydrated type 1 collagen matrix.…”

“…(Mamdouh et al, 2003(Mamdouh et al, , 2008). To avoid bias in our interpretation, all leukocytes in contact with the endothelium were examined, not just the ones that appeared to be undergoing TEM.…”

Ultrastructural Dynamics of Transendothelial Migration of Lymphocytes Through High Endothelial Venules (HEVs) of the Mucosa Associated Peyer’s Patches

“…However, they disappeared during the engulfment of emigrating lymphocytes, probably due to redirection of them to plasma membrane of active endothelial cell (22,23). Because there is no specific marker for determining the LBRC, we are not sure whether these structures are LBRC.…”

“…Therefore, VVOs and caveolae have been considered as fundamental membrane fusion elements for pore formation during the transcellular migration (21). On the other hand, the unique structural figures called "lateral border recycling compartment-LBRC" were distinct from VVOs (22,23) and could function as a cellular storage for some of adhesion molecules including PECAM, CD99 and JAM-A (24). It has been reported that LBRC is essential for paracellular and transcellular migration of lymphocytes in a microtubule-dependent manner (24).…”

Tight junctions in the testis: new perspectives

“…In this context, it is worth noting that as leucocytes cross the endothelium, they become surrounded by the lateral border recycling compartment (LBRC), an interconnected reticulum of membrane that functions as a 'channel.' This channel is lined with several proteins, namely PECAM (platelet endothelial cell adhesion molecule), CD99 (cluster of differentiation 99) and JAM-A but not VE-cadherin which appeared to be endocytosed (Xiao et al 2005;Gavard & Gutkind 2006), that are needed for leucocytes to cross the endothelium (Mamdouh et al 2003(Mamdouh et al , 2008(Mamdouh et al , 2009. Interestingly, depolymerization of microtubules blocked the accumulation of the LBRC around leucocytes and transmigration (Mamdouh et al 2009).…”