Local induction of lymphangiogenesis with engineered fibrin-binding VEGF-C promotes wound healing by increasing immune cell trafficking and matrix remodeling

Abstract

Lymphangiogenesis occurs in inflammation and wound healing, yet its functional roles in these processes are not fully understood. Consequently, clinically relevant strategies for therapeutic lymphangiogenesis remain underdeveloped, particularly using growth factors. To achieve controlled, local capillary lymphangiogenesis with protein engineering and determine its effects on fluid clearance, leukocyte trafficking, and wound healing, we developed a fibrin-binding variant of vascular endothelial growth factor C (FB-VEGF-C) that is slowly released upon demand from infiltrating cells. Using a novel wound healing model, we show that implanted fibrin containing FB-VEGF-C, but not free VEGF-C, could stimulate local lymphangiogenesis in a dose-dependent manner. Importantly, the effects of FB-VEGF-C were restricted to lymphatic capillaries, with no apparent changes to blood vessels and downstream collecting vessels. Leukocyte intravasation and trafficking to lymph nodes were increased in hyperplastic lymphatics, while fluid clearance was maintained at physiological levels. In diabetic wounds, FB-VEGF-C-induced lymphangiogenesis increased extracellular matrix deposition and granulation tissue thickening, indicators of improved wound healing. Together, these results indicate that FB-VEGF-C is a promising strategy for inducing lymphangiogenesis locally, and that such lymphangiogenesis can promote wound healing by enhancing leukocyte trafficking without affecting downstream lymphatic collecting vessels.

Extracellular Matrix‐Based Strategies for Immunomodulatory Biomaterials Engineering

“…PAR‐1 has been found to be required for DC trafficking and presentation for T cell activation . Moreover, fibrin can bind vascular endothelial growth factor (VEGF)‐C during wound healing, and this sequestration is required for lymphangiogenesis or the formation of new lymphatic vessels, which is key to maintaining communication between antigen presenting cells and the adaptive immune compartment . Although fibrin also contains adhesion binding sites such as RGD, which were described above to influence B cell maturation, it remains unknown whether fibrin has any direct effects on the adaptive immune compartment.…”

Lymphatic Vessels Enhancing Adaptive Immunity Deteriorates Renal Inflammation and Renal Fibrosis

“…LVs have been found to play a pivotal role in immune-related diseases in the recent two decades. A large amount of literature reports that lymphangiogenesis is often associated with pathological conditions, such as tumor metastasis [42], injury repair [43], and chronic inflammation [44]. Renal lymphangiogenesis is associated with renal fibrosis, inflammation, and transplant rejection.…”

Biomaterials as Tools to Decode Immunity

“…Lymphatic and blood vessels provide a means for the body to transport immune cells, fluids, and signaling molecules across great distances . These lymphatic vessels contain lymphatic endothelial cells (LECs) that regulate immune cell functions by secreting cytokines, expressing ligands that activate immune cells, and displaying molecules that control cellular migration . These interactions allow immune cells to communicate with the ECM and vice versa.…”

“…However, lymphatic development and the impact it has on immune cell trafficking has historically been difficult to study because of the rapid diffusion of soluble proteins following injection into animals, as well as safety concerns associated with repeated injection of lymphatic growth factors such as vascular endothelial growth factor C (VEGF‐C). One new alternative is a 3D culture system in which the growth factors present such as VEGF‐C are bound to hydrogels made of naturally occurring fibrin proteins . When ECM proteins are cleaved by enzymes produced by immune cells during the process of ECM remodeling, VEGF‐C is released over 10–12 days.…”