Zebrafish as a model to study autophagy and its role in skeletal development and disease

Abstract

In the last twenty years, research using zebrafish as a model organism has increased immensely. With the many advantages that zebrafish offer such as high fecundity, optical transparency, ex vivo development, and genetic tractability, they are well suited to studying developmental processes and the effect of genetic mutations. More recently, zebrafish models have been used to study autophagy. This important protein degradation pathway is needed for cell and tissue homeostasis in a variety of contexts. Correspondingly, its dysregulation has been implicated in multiple diseases including skeletal disorders. In this review, we explore how zebrafish are being used to study autophagy in the context of skeletal development and disease, and the ways these areas are intersecting to help identify potential therapeutic targets for skeletal disorders.

A homozygous hypomorphicBNIP1variant causes an increase in autophagosomes and reduced autophagic flux and results in a spondylo‐epiphyseal dysplasia

“…The epiphyseal growth plate required for long bone growth is a transient form of cartilage and composed of chondrocytes. Chondrocyte differentiation, function, and survival depend on vital autophagy (Aghajanian & Mohan, 2018; Moss et al, 2020; Shapiro et al, 2014). Mice with a chondrocyte‐specific knockout of Atg5 or Atg7 , both autophagy‐related genes, have stunted growth.…”

Control of the Autophagy Pathway in Osteoarthritis: Key Regulators, Therapeutic Targets and Therapeutic Strategies

“…The CRISPR/Cas9 system in fact not only allows to knock out specific genes and functions, but by using modified versions of the Cas9 enzyme, it becomes possible to originate recombinant proteins that can act as transcriptional activators and repressors, as well as epigenetic modulators [ 71 ], to study in a more precise way the regulation of specific genes [ 72 ]. The possibility to originate new cellular and animal models [ 73 , 74 ] will be very helpful to overcome the limited availability of animal models of the disease. In addition, the availability of different models will make drug screening aimed at identifying new therapies much more efficient, as will the possibility of studying new therapeutic approaches based on gene therapy [ 75 ].…”

In vivo Functional Genomics for Undiagnosed Patients: The Impact of Small GTPases Signaling Dysregulation at Pan-Embryo Developmental Scale

“…Stable line used to follow zebrafish autophagy in vivo (Moss et al, 2020) MitoID RAB and other small GTPases Molecular tool to identify effectors and regulators by in vivo proximity biotinylation approach with mitochondrially localized GTPases (Gillingham et al, 2019) Examples of specific tools used in zebrafish are italicized.…”

“…In addition to standard subcellular markers labeling nuclei and cell membranes, specific organelles and vesicle markers are available in zebrafish (reviewed by Vacaru et al, 2014). Among those, GalT-GFP fish expressing galactose-1-phosphate uridyl transferase (Gerhart et al, 2012) are useful to map trans-Golgi, whereas Lamp2-mCherry can be used to visualize lysosomes (Sasaki et al, 2017), and GFP-Map1Lc3 has been already employed to image disease-associated autophagy in vivo (Moss et al, 2020).…”