Background

This invention was co-developed by researchers at the University of Manitoba in partnership with the University of California, Davis.

SUMMARY:

T cell migration is a crucial element of the immune response and important for maintaining skin homeostasis. Disruption of normal T cell migration contributes to various skin diseases. The migratory response of T cells is dynamically mediated by specific chemotactic signaling during skin inflammation and facilitates T cell homing to different skin layers.

Researchers at the University of Manitoba and University of California, Davis have developed a novel skin-on-chip (SoC) model that replicates key features and responses of human T cells during skin inflammation. The physical structure of the SoC device combines epithelial, dermal, and endothelial components originating from human cell lines and extracellular matrix.

The SoC model mimics the in vivo ratio of different skin layers in normal human skin and enables the creation of dynamic single or co-existing chemical gradients of relevant chemokines to study the dynamic migratory behaviors of T cells. The SoC model provides a novel platform to dissect complex physiological or pathological responses of T cell migration into multiple processes and to investigate the effects of each individual component (e.g., ECM, cell layer, and chemokines) involved in these processes.

Technology Overview

The general purpose of this skin‑on‑chip model (SoC) is to replicate the physiological microenvironment of human skin for investigating the migratory responses of T cells in controlled complex chemical gradients. This microfluidics-based SoC model mimics the in vivo ratio of different skin layers in normal human skin and enables the creation of dynamic single or co-existing gradients of relevant chemokine. The model provides a novel platform to dissect complex physiological or pathological responses of T cell migration into multiple processes and to investigate the effects of each individual component (e.g., ECM, cell layer, and chemokines) involved in these processes.

Skin inflammatory processes trigger T cell trafficking to regional lymph nodes, and this involves down-regulation of the C-C motif chemokine receptor 7 (CCR7)/C-C motif chemokine ligand 21 and 19 (CCL21/19) axis. In contrast, the C-C motif chemokine receptor 6 (CCR6)/C-C motif chemokine ligand 20 (CCL20) system is up-regulated in the dermis and epidermis, and this facilitates T cell homing to the inflammatory site. In psoriatic skin lesions, CCR6/CCL20 signaling facilitates inflammatory processes by promoting the migration and accumulation of T cells at psoriasiform sites. This CCR6-mediated T cell migration can be inhibited by an engineered CCL20 locked dimer (CCL20LD).

Our SoC was specifically designed to investigate the potential immunotherapeutic use of CCL20LD as a drug therapy for CCR6-mediated skin diseases, such as psoriasis (Figure 1).

To date, we have demonstrated that CCL20 (C-C motif chemokine ligand 20)-dependent migration of T cells through a HUVEC cell layer or collagen matrix alone was significantly inhibited in the presence of a uniform background of CCL20 locked dimer (CCL20LD). This suggests the use of CCL20LD as a drug for CCR6-mediated skin diseases and also serves as a demonstration of the capability of our system to serve as an effective and robust drug screening device.

The ability of T cells to migrate from a CCL20 wild-type (CCL20WT) gradient towards a CXCL12 gradient through a human immortalized keratinocyte (HaCaT) cell layer or collagen matrix was significantly reduced in the presence of a uniform sphingosine-1-phosphate (S1P) background. These results demonstrate the importance of S1P for T cell retention in the inflamed tissues. In our SoC model, the _in vivo_skin inflammation was replicated by stimulating HaCaT cells with the inflammatory cytokine TNF-α.

Collectively, our SoC model recreates a dynamic multi-cellular microenvironment that enables tracking and quantification of T cell migration at a single-cell level in response to physiological cutaneous inflammatory mediators and potential drugs.

KEY PUBLICATION:

Ren et al. 2021. Investigations on T cell transmigration in a human skin-on-chip (SoC) model. LAB ON CHIP. DOI:10.1039/d0lc01194k

Benefits

Compared with other existing cell migration approaches, this model has the following innovative features:

1) This SoC model is developed based on a novel microfluidic device that permits four independent experiments to be performed simultaneously, which increases experimental throughput;

2) The unique design of micropillars in the major compartment conducted with hydrophobicity restoration of PDMS enables the precise configuration of cellular components and provides multiple view regions for investigating cell migration at a single-cell level;

3) This SoC model reconstitutes all the key features of human skin, including epithelial, dermal, and endothelial components at the _in vivo_ratios;

4) All of the cellular components in the model originated from human primary cells and cell lines, enabling better prediction of migratory responses;

5) This model enables the generation of dynamic single or co-existing chemical gradients in a standalone manner based on chemical diffusion from one side channel to the other through the ECM, which is stable and can last for at least eight hours;

6) The loaded T cells are attached by one side of the ECM to achieve controlled initial positions relative to the gradient direction, which eliminates variations of cell migration measurements due to different initial cell positions. At the same time, time-lapse microscopy and cell tracking become optional, thus significantly simplifying cell migration analysis; and

7) The SoC model permits on-chip simulation of skin inflammation using inflammatory mediators. Its ability to investigate the role of physiologically relevant chemical fields in mediating cutaneous T cell homing may serve as a novel drug screening platform to identify compounds targeting skin diseases (e.g., psoriasis).

Applications

This invention is a useful research tool for studying skin biology, disorders, and diseases. In addition, it can be used as a powerful drug testing assay for skin disease. Note that this SoC model is not limited to studying T cell transmigration but can also be used to test other immune cell types (e.g. neutrophils (successfully demonstrated)). Furthermore, the core features of this SoC model can be modified to model other systems and to study transmigration of different cell types in context. Potential licensees of this invention include, but are not limited to, microfluidic companies, other biotechnology companies, and pharmaceutical companies.

Opportunity

The University of Manitoba in partnership with the University of California, Davis is actively seeking a licensee to license the patent rights to move this technology to the market.

The University of Manitoba in partnership with the University of California, Davis readily welcomes interactions with any investor or entrepreneur that would like to license the patent rights to create of a start‑up based on this novel technology.