# Defining the Human Articular Chondrocyte Lineage

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2022 · $509,893

## Abstract

Progressive joint degeneration, as occurs in osteoarthritis, is common and current therapies for failing joints
are limited. Attempts to induce repair of damaged articular cartilage in situ have had limited efficacy because
this tissue seems to lack intrinsic regenerative capacity after birth. We hypothesize that understanding how
pluripotent stem cells (PSCs) become articular chondrocytes (ACs) in vitro, and maintain this phenotype in
vivo, will lead to improved strategies for repairing and regenerating cartilage. We will therefore identify genes
and biological mechanisms responsible for enabling human (h)PSCs to become ACs. We will also identify
factors that enable ACs to better resist becoming hypertrophic chondrocytes when challenged in vitro and
implanted in vivo. Using our previously published methods for generating articular cartilage tissues from
hPSCs, we will determine when these cells become fully committed to the AC lineage. We will accomplish this
by inducing articular chondrocyte differentiation for different lengths of time using TGFβ3, and then evaluating
when the cells no longer become hypertrophic after BMP4 exposure in vitro and implantation into
immunodeficient mice in vivo. In order to identify factors that maintain AC identity and enhance AC resilience in
the presence these challenges, we will define the molecular profiles of hPSC-derived chondrocytes before and
after they become ACs using RNA and ATAC sequencing. We will also compare the expression profiles of
chondrogenic progenitors, articular chondrocytes, and growth plate chondrocytes derived from mouse ESC
lines that we have CRISPR/Cas9 edited to express fluorescent proteins under the control of lineage-specific
promoters. From these data, we will identify and prioritize for downstream studies candidate transcription
factors, chromatin modifying enzymes, and signaling pathway components that are involved in AC lineage
commitment. We will then assess the importance of individual candidates using genetic approaches (e.g.,
regulating gene expression using modified Cas9 proteins) and, when possible, pharmacologic approaches
(e.g., pathway agonists and antagonists) in the hPSC/mESC differentiation assays. By understanding how
ACs are induced from hPSCs and how the AC phenotype can be maintained in the presence of external
challenges, we will discover new ways to repair, replace, or regenerate damaged cartilage in patients.

## Key facts

- **NIH application ID:** 10357576
- **Project number:** 5R01AR073821-04
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** April Marie Craft
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $509,893
- **Award type:** 5
- **Project period:** 2019-04-01 → 2024-02-29

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10357576

## Citation

> US National Institutes of Health, RePORTER application 10357576, Defining the Human Articular Chondrocyte Lineage (5R01AR073821-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10357576. Licensed CC0.

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