Abstract
Autophagy is a catabolic process responsible for the removal of waste and damaged cellular components by lysosomal degradation. It plays a key role in fundamental cell processes, including ER stress mitigation, control of cell metabolism, and cell differentiation and proliferation, all of which are essential for cartilage cell (chondrocyte) development and survival, and for the formation of cartilage. Correspondingly, autophagy dysregulation has been implicated in several skeletal disorders such as osteoarthritis and osteoporosis. To test the requirement for autophagy during skeletal development in zebrafish, we generated an atg13 CRISPR knockout zebrafish line. This line showed a complete loss of atg13 expression, and restricted autophagic activity in vivo. In the absence of autophagy, chondrocyte maturation was accelerated, with chondrocytes exhibiting signs of premature hypertrophy. Focussing on the jaw element, autophagy disruption affected joint articulation causing restricted mouth opening. This gross behavioural phenotype corresponded with a failure to thrive, and death in homozygote atg13 nulls within 17 days. Taken together, our results are consistent with autophagy contributing to the timely regulation of chondrocyte maturation and for extracellular matrix formation.
| Original language | English |
|---|---|
| Article number | e22002 |
| Pages (from-to) | 1-34 |
| Number of pages | 34 |
| Journal | FASEB Journal |
| Volume | 35 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 28 Oct 2021 |
Bibliographical note
Funding Information:Joanna J. Moss was funded by the Wellcome Trust Dynamic Molecular Cell Biology PhD Programme at the University of Bristol (083474). Martina Wirth and Sharon A. Tooze were supported by The Francis Crick Institute which receives its core funding from Cancer Research UK (FC001187, FC001999), the UK Medical Research Council (FC001187, FC001999) and the Wellcome Trust (FC001187, FC001999). Martina Wirth had been supported by a European Union Marie Curie fellowship IEF‐330396. Chrissy L. Hammond was funded by Versus Arthritis senior fellowship 21937.
Funding Information:
Joanna J. Moss was funded by the Wellcome Trust Dynamic Molecular Cell Biology PhD Programme at the University of Bristol (083474). Martina Wirth and Sharon A. Tooze were supported by The Francis Crick Institute which receives its core funding from Cancer Research UK (FC001187, FC001999), the UK Medical Research Council (FC001187, FC001999) and the Wellcome Trust (FC001187, FC001999). Martina Wirth had been supported by a European Union Marie Curie fellowship IEF-330396. Chrissy L. Hammond was funded by Versus Arthritis senior fellowship 21937. The authors thank Dr Sally Hobson and Dr Chris Neal for their support in processing and imaging the EM data and the staff of the Wolfson Bioimaging Centre for confocal microscope (Leica SP5-II) access and imaging support. The authors also thank Dr Stephen Cross for his help with image analysis and in the development of a modular analysis program. Additionally, the authors also thank Mathew Green and technical staff at the zebrafish aquarium within the University of Bristol's Animal Scientific Unit, as well as the Aquatics BRF staff at the Francis Crick Institute for providing animal husbandry and management.
Publisher Copyright:
© 2021 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.
Keywords
- Atg13
- Zebrafish
- Autophagy
- Chondrocytes
- Joints