# Biomechanical influence of ECM remodeling on the developing enthesis

> **NIH NIH R01** · UNIVERSITY OF COLORADO · 2020 · $353,374

## Abstract

PROJECT SUMMARY
 Despite decades of work, there has been little success in engineering scaffolds that can successfully
restore the enthesis, the tissue smoothly transfers muscle-generated force from tendon to bone. This region is
prone to failure from excessive mechanical loading and in many cases the interface cannot be surgically
reestablished due to the complexity and low cellularity of the enthesis. A reason engineered scaffolds lack the
ability to restore the damaged enthesis is that the design predominantly mimics the architecture and
composition of the mature tissue. What is rarely taken into consideration in scaffold design is that tissues
undergo extensive ECM remodeling during development, which plays a significant role in directing cellular
behavior in the formation of the mature tissue. Researchers have been unable to capitalize on these instructive
cues for scaffold design due to the limited knowledge regarding the composition, turnover, organization and
mechanical properties of developing musculoskeletal tissues.
 Our long-term objective is to create scaffolds that can biomechanically direct cells to rebuild damaged
tissues; therefore, it is critical to identify how this is accomplished in vivo. To achieve our objective, we need to
first address the following questions: 1) What are the dynamics of ECM expression over the course of enthesis
formation? 2) How are these components organized in 3D? 3) How does this organization influence the
mechanical environment? 4) How does mechanical loading regulate enthesis assembly?
 To directly quantify ECM protein incorporation into the matrix of developing tendon, enthesis and cartilage,
we will label tissues at various stages of murine development with non-canonical amino acids (ncAAs). The
bioorthogonal handles on the ncAAs enable the identification and localization of newly synthesized proteins
using click chemistry. To see how individual ECM components are spatially distributed with respect to cells in
the developing enthesis, we will use optical clearing methods to visualize murine tissues containing
fluorescently labeled tendon and cartilage progenitors. Using confocal microscopy and 3D image processing
algorithms, we will characterize how morphology at the intracellular, cellular and tissue scale change due to
development and embryonic motility. To test the hypothesis that the stiffness across the enthesis will develop a
steeper gradient upon the onset of embryonic and postnatal motility, we will utilize our novel atomic force
microscopy method that can measure the stiffness of cells and ECM within viable tissues. This hypothesis will
be directly tested by employing the mdg model of muscular dysgenesis, a mouse line in which skeletal muscle
contractility is inhibited during embryogenesis. By correlating the mechanical properties with the compositional
and structural characterization, we expect to identify a set of scaffold parameters that will promote cellular
behaviors necessary for en...

## Key facts

- **NIH application ID:** 10250802
- **Project number:** 7R01AR071359-04
- **Recipient organization:** UNIVERSITY OF COLORADO
- **Principal Investigator:** Sarah Calve
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $353,374
- **Award type:** 7
- **Project period:** 2020-09-01 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10250802

## Citation

> US National Institutes of Health, RePORTER application 10250802, Biomechanical influence of ECM remodeling on the developing enthesis (7R01AR071359-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10250802. Licensed CC0.

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