Published in Science Advances: Using Superhuman Cells to Determine How Engineered Hydrogels Direct Immune Cell Function

Hydrogels have a wide number of biomedical applications, such as in tissue engineering, wound healing, cancer therapies, and vaccine delivery and can now be engineered to include components that direct immune cell function and therapeutic response. Though promising for the improvement of regenerative medicine and immunotherapies in the future, the way specific immune cells respond to hydrogel immune signals is still poorly understood and remains a challenge for hydrogel development.

Macrophages are known to have a wide range of functions, some of which can aid in tissue repair and revascularization after injury. However, measuring just cell surface markers can result in an incomplete picture of macrophage function. IsoPlexis’ functional phenotyping solution fills this gap by identifying rare subsets of cells that simultaneously secrete multiple cytokines to orchestrate key immune responses. These superhuman cells are predictive of patient response and disease progression in vivo. By uncovering these superhuman cells, researchers can more quickly advance therapeutic development and better understand the impact of engineered hydrogels on macrophage function.

Using Single-Cell and Bulk Proteomics to Analyze Macrophage Functionality

Developing hydrogels that can best direct the immune cell responses could accelerate the success of hydrogel implants and improve wound healing. The authors of a study recently published in Science Advances sought to explore the progression of inflammation following implantation of two different subsets of engineered hydrogels (Arg-Gly-Asp [RGD] and RDG-presenting hydrogels) using single-cell proteomics to analyze macrophage functionality.

The team used both IsoPlexis’ functional proteomics (Mouse Adaptive Immune Panel) to conduct in-depth cytokine profiling of single macrophages exposed to RGD- or RDG-presenting hydrogels (in comparison to each other) as well as to the hydrogels presented with both vascular endothelial growth factor (VEGF; VEGF-loaded) and without VEGF (VEGF-unloaded). Using IsoPlexis’ platforms, the researchers aimed to better characterize the differences in functionality between the two engineered hydrogels in the wound healing process.

The study took place over 14 days, during which the monocytes and macrophages transitioned from pro-inflammatory to pro-healing phenotypes After 7 days, the hydrogels were removed, and the immune cells were isolated for testing, where researchers worked to characterize the functionality of the macrophages after exposure to the hydrogels.

Single-Cell Proteomics Revealed Promising Results

The team found that RGD presentation directs the phenotype of macrophages shifting from a pro-inflammatory state to a more chemoattractive and effector state (pro-healing). In addition, VEGF incorporation into adhesive hydrogels also increased pro-healing macrophage functions. They also found that these healing functions were increased for RGD-presenting hydrogels, whereas regulator and inflammatory cytokines were decreased, suggesting distinct cell function of the immune cell subset when stimulated.

The authors concluded:

“Single-cell proteomics revealed previously unreported adhesion-dependent functional heterogeneity in immune populations defined as relatively homogeneous by traditional surface markers.”1

Thus, IsoPlexis’ platform captured the functional heterogeneity of immune cells that was missed by traditional technologies.

The Single-Cell Proteomics Uncovers Relationship between Macrophage and Superhuman Cells

The results from this study suggest that hydrogels with functional ligands can be used to modulate immune response. IsoPlexis’ unique single-cell and functional secretomic analysis provided unique insight into the diversity of macrophage signaling and demonstrated a relationship between macrophage adhesion and polyfunctionality for the first time.

The ability to characterize individual immune cells allows researchers to take their research one step further, uncovering knowledge not previous known and as a result, advancing curative medicines.



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