# Mapping protein dynamics and their origin at biomaterial surfaces in vivo

> **NIH NIH R21** · UNIVERSITY OF COLORADO · 2021 · $167,473

## Abstract

Therapies to repair or regenerate damage to the musculoskeletal system often involve the implantation of
synthetic materials to stabilize tissues or promote regrowth. However, synthetic materials induce a foreign body
response (FBR), which can lead to adverse outcomes. Our ability to design effective therapeutic strategies to
mitigate the FBR is hampered by an incomplete understanding of the molecular mechanisms that trigger the
FBR. The current dogma of the FBR assumes that serum proteins adsorb to biomaterial surfaces and unfold,
leading to irreversible adsorption and creating damage-associated molecular patterns (DAMPs) that initiate
inflammation. Our recent studies suggest that this view is insufficient and instead that proteins interact with
surfaces dynamically and that DAMPs may arise from multiple different sources. To this end, this proposal aims
to test the hypothesis that the adsorption of proteins onto implanted biomaterials is dynamic (turning over
continually and changing in time), and that the FBR is maintained by DAMPs derived from serum and by the
continuous generation of DAMPs that are produced by recruited myeloid cells. Two specific aims were developed
to test this hypothesis. Specific Aim #1 will determine the identity of surface-adsorbed proteins over time
in the FBR using bioorthogonal tagging. This aim will incorporate the methionine (Met) analog
azidohomoalanine to ubiquitously tag newly synthesized proteins at different times during the FBR in wildtype
mice with implants. The tagged and untagged newly synthesized proteins will be quantified and the proteins
identified with LC-MS/MS to determine the transient nature of the surface-adsorbed proteins. Specific Aim #2
will determine the origin of surface-adsorbed proteins and their identity in the FBR using cell-specific
bioorthogonal tagging. This aim will use a recently created mouse line that has a point mutation in methionyl-
tRNA synthetase (MetRS*) that enables cell-specific loading (via Cre drivers) of the Met analog azidonorleucine
into newly synthesized proteins. Albumin-Cre and LysM-Cre drivers will be used to determine the origin of the
adsorbed proteins from serum and myeloid cells, respectively. When combined with LC-MS/MS, the identity of
the adsorbed proteins from each source will also be determined. Each aim will investigate silicone as a model
implant, having a surface chemistry that is either hydrophobic (native surface) or hydrophilic (plasma-treated),
to study the role of hydrophobicity on the dynamics of surface-adsorbed proteins. In addition, a subset of proteins
from the LC-MS/MS results will be tested for their ability to activate macrophages in vitro and act as DAMPs. In
summary, this exploratory project will utilize recently developed in vivo protein labeling techniques to answer
fundamental questions about the events that trigger the FBR. Through this understanding, this project will
generate new hypotheses and inform the rational design of biomate...

## Key facts

- **NIH application ID:** 10206869
- **Project number:** 1R21AR079154-01
- **Recipient organization:** UNIVERSITY OF COLORADO
- **Principal Investigator:** Stephanie J Bryant
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $167,473
- **Award type:** 1
- **Project period:** 2021-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10206869

## Citation

> US National Institutes of Health, RePORTER application 10206869, Mapping protein dynamics and their origin at biomaterial surfaces in vivo (1R21AR079154-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10206869. Licensed CC0.

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