Endothelial and leukocyte inflammatory signaling pathways

The endothelial and leukocyte inflammatory signaling pathways represent a complex, multi-step cascade essential for the recruitment of immune cells from the bloodstream to sites of tissue injury or infection [3.1.1, 3.2.5]. This process, often termed the leukocyte adhesion cascade, involves sequential interactions: initial tethering and rolling mediated by selectins (E-, P-, and L-selectin), followed by firm adhesion triggered by chemokines and mediated by integrins (such as LFA-1 and VLA-4) binding to immunoglobulin-like cell adhesion molecules (ICAM-1 and VCAM-1) on the activated endothelium [3.2.1, 3.2.3, 3.2.4]. Intracellular signaling within both leukocytes and endothelial cells, involving pathways like NF-kappaB, MAPKs, and Rho GTPases, regulates the expression of these molecules and the subsequent transendothelial migration [3.1.5, 3.2.1, 3.2.4]. Dysregulation of these pathways is a hallmark of chronic inflammatory and autoimmune diseases, including atherosclerosis, multiple sclerosis, and inflammatory bowel disease [3.1.2, 3.2.2]. Consequently, these pathways are major therapeutic targets, with drugs like natalizumab and vedolizumab successfully blocking specific adhesion steps to treat inflammatory conditions [3.1.2, 3.1.3]. However, such interventions carry risks of systemic immunosuppression and serious opportunistic infections, such as progressive multifocal leukoencephalopathy (PML) [3.1.2, 3.1.3].

Other names

Leukocyte-endothelial interactionLeukocyte adhesion cascadeEndothelial activation pathwayTransendothelial migration signalingLeukocyte recruitment cascade

Drugs targeting these pathways primarily function by inhibiting the physical interaction between leukocytes and the vascular endothelium. This is achieved through the blockade of cell adhesion molecules (e.g., ICAM-1, VCAM-1), selectins (e.g., P-selectin), or their corresponding leukocyte integrin receptors (e.g., alpha-4 beta-7, LFA-1). Additionally, some agents modulate the intracellular signaling cascades, such as the NF-kappaB or MAPK pathways, to reduce the expression of pro-inflammatory mediators and adhesion molecules [3.1.1, 3.1.2, 3.1.5].