Analysis of transgenic zebrafish expressing the Lenz-Majewski syndrome gene PTDSS1 in skeletal cell lineages

High Bone Mass Disorders: New Insights From Connecting the Clinic and the Bench

Monogenic high bone mass (HBM) disorders are characterized by an increased amount of bone in general, or at specific sites in the skeleton. Here, we describe 59 HBM disorders with 50 known disease-causing genes from the literature, and we provide an overview of the signaling pathways and mechanisms involved in the pathogenesis of these disorders. Based on this, we classify the known HBM genes into HBM (sub)groups according to uniform Gene Ontology (GO) terminology. This classification system may aid in hypothesis generation, for both wet lab experimental design and clinical genetic screening strategies. We discuss how functional genomics can shape discovery of novel HBM genes and/or mechanisms in the future, through implementation of omics assessments in existing and future model systems. Finally, we address strategies to improve gene identification in unsolved HBM cases and highlight the importance for cross-laboratory collaborations encompassing multidisciplinary efforts to transfer knowledge generated at the bench to the clinic. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Zebrafish Models for Human Skeletal Disorders

In 2019, the Nosology Committee of the International Skeletal Dysplasia Society provided an updated version of the Nosology and Classification of Genetic Skeletal Disorders. This is a reference list of recognized diseases in humans and their causal genes published to help clinician diagnosis and scientific research advances. Complementary to mammalian models, zebrafish has emerged as an interesting species to evaluate chemical treatments against these human skeletal disorders. Due to its versatility and the low cost of experiments, more than 80 models are currently available. In this article, we review the state-of-art of this “aquarium to bedside” approach describing the models according to the list provided by the Nosology Committee. With this, we intend to stimulate research in the appropriate direction to efficiently meet the actual needs of clinicians under the scope of the Nosology Committee.

Effects of polyethylene microplastics on the microbiome and metabolism in larval zebrafish

Various microplastics (MPs) are found in the environment and organisms. MP residues in organisms can affect health; however, their impacts on metabolism in aquatic organisms remain unclear. In this study, zebrafish embryos were exposed to polyethylene MPs with sizes ranging from 1 to 4 μm at concentrations of 0, 10, 100, and 1000 μg/L for 7 days. Through qPCR technology, the results indicated that zebrafish exposed to polyethylene MPs exhibited significant change in microbes of the phyla Firmicutes, Bacteroidetes, Proteobacteria, and Verrucomicrobia, etc. Moreover, 16S RNA gene sequencing revealed that there was a significant difference in alpha diversity between the control and 1000 μg/L MP-treated groups. At the genus level, the abundance of Aeromonas, Shewanella, Microbacterium, Nevskia and Methyloversatilis have increased remarkably. Conversely, the abundance of Pseudomonas, Ralstonia and Stenotrophomonas were significant reduction after MPs exposure. In addition, the levels of TG (triglyceride), TCHO (total cholesterol), NEFA (nonesterified fatty acid), TBA (total bile acid), GLU (glucose) and pyruvic acid significantly changed in MP-treated larval zebrafish, indicating that their metabolism was disturbed by MPs. Transcriptional levels of glucose and lipid metabolism-related genes showed a decreasing trend. Furthermore, LC/MS-based nontargeted metabolomics analysis demonstrated that a total of 59 phospholipid-related substances exhibited significant changes in larval fish treated with 1000 μg/L MPs. The mRNA levels of phospholipid metabolism-related genes were also obviously changed. Pearson correlation analysis indicated that the abundance of Aeromonas, Shewanella and Chitinibacter bacteria showed a negative correlation with most phospholipids, while Nevskia, Parvibacter and Lysobacter showed a positive correlation with most phospholipids. Based on these results, it is suggested that 1-4 μm PE-MPs could impact the microbiome and metabolism of larval zebrafish. All of these results indicated that the health risk of MPs cannot be ignored.

Zebrafish Models of Human Skeletal Disorders: Embryo and Adult Swimming Together

Danio rerio (zebrafish) is an elective model organism for the study of vertebrate development because of its high degree of homology with human genes and organs, including bone. Zebrafish embryos, because of the optical clarity, small size, and fast development, can be easily used in large-scale mutagenesis experiments to isolate mutants with developmental skeletal defects and in high-throughput screenings to find new chemical compounds for the ability to revert the pathological phenotype. On the other hand, the adult zebrafish represents another powerful resource for pathogenic and therapeutic studies about adult human bone diseases. In fish, some characteristics such as bone turnover, reparation, and remodeling of the adult bone tissue cannot be found at the embryonic stage. Several pathological models have been established in adult zebrafish such as bone injury models, osteoporosis, and genetic diseases such as osteogenesis imperfecta. Given the growing interest for metabolic diseases and their complications, adult zebrafish models of type 2 diabetes and obesity have been recently generated and analyzed for bone complications using scales as model system. Interestingly, an osteoporosis-like phenotype has been found to be associated with metabolic alterations suggesting that bone complications share the same mechanisms in humans and fish. Embryo and adult represent powerful resources in rapid development to study bone physiology and pathology from different points of view.