The proposal aims to examine the neutrophil response in terms of neutrophil extracellular trap (NET) formation (process known as NETosis) to three-dimensional regeneration templates with varying yet controlled architecture and composition. Templates will be fabricated by air- impedance electrospinning such that the resulting architectures vary in fiber diameter, pore size, and composition to create diverse microenvironments to allow examination of the role of each variable in regulating the NET formation and subsequent cellular interactions and responses to this preconditioning event. The overriding hypothesis is that an electrospun template architecture and composition will modulate the degree of NETosis such that this neutrophil preconditioning event would promote/enhance regeneration and reduce implant failure (i.e. acute thrombosis and enhanced inflammation/tissue destruction). More specifically, Aim 1 will define the role of template architecture and composition in modulating template-interacting neutrophil NETosis, and determine the subsequent in vitro role of this preconditioning event.
Aim 2 will then determine the in vivo template invoked degree of neutrophil NETosis and thus test whether the in vitro results are correlative as well as the outcomes associated with the degree of NETosis-template preconditioning in a rat subcutaneous model. It is anticipated that increasing template fiber diameters/pore sizes and particular compositions will invoke a minimal degree of NETosis, leading to recruited neutrophil and macrophage phenotypes that secrete cytokines and MMPs that favor tissue regeneration. The ultimate goal is to be able to define a template architecture and composition that is capable of supporting an innate immunity cell line-instructed and enhanced regeneration upon implantation as initiated and/or directed by the template-interacting, microenvironment neutrophils to replace or repair damaged or diseased tissues and organs.
This project is designed to examine the function of the neutrophils, an abundant and immediately responding immune cell to an implant, in response to interacting with an acellular tissue regeneration templates fabricated to promote growth of new tissues or organs. More specifically, the study is focused on a newly discovered neutrophil function in which the cellular DNA is extruded to form fibers that aid in trapping and killing bacteria but may also function to treat or precondition the template surface for further immune cells to interact and respond with yet unknown consequences. Thus, this study will define the neutrophil response to template architecture and composition as well as the other immune cell responses to the DNA fibers presented in hopes that the templates can be designed and tailored to promote and enhance the regeneration, as set into motion by the initial neutrophil response, of new tissues and organs critically needed by large populations due to trauma and disease conditions.
