Adult chondrogenesis and spontaneous cartilage repair in the skate, Leucoraja erinacea

Mammalian articular cartilage is an avascular tissue with poor capacity for spontaneous repair. Here, we show that embryonic development of cartilage in the skate (Leucoraja erinacea) mirrors that of mammals, with developing chondrocytes co-expressing genes encoding the transcription factors Sox5, Sox6 and Sox9. However, in skate, transcriptional features of developing cartilage persist into adulthood, both in peripheral chondrocytes and in cells of the fibrous perichondrium that ensheaths the skeleton. Using pulse-chase label retention experiments and multiplexed in situ hybridization, we identify a population of cycling Sox5/6/9+ perichondral progenitor cells that generate new cartilage during adult growth, and we show that persistence of chondrogenesis in adult skates correlates with ability to spontaneously repair cartilage injuries. Skates therefore offer a unique model for adult chondrogenesis and cartilage repair and may serve as inspiration for novel cell-based therapies for skeletal pathologies, such as osteoarthritis

Adult chondrogenesis and spontaneous cartilage repair in the skate, Leucoraja erinacea

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marconi, A., Hancock-Ronemus, A., & Gillis, J. A. Adult chondrogenesis and spontaneous cartilage repair in the skate, Leucoraja erinacea. Elife, 9, (2020): e53414, doi:10.7554/elife.53414.Mammalian articular cartilage is an avascular tissue with poor capacity for spontaneous repair. Here, we show that embryonic development of cartilage in the skate (Leucoraja erinacea) mirrors that of mammals, with developing chondrocytes co-expressing genes encoding the transcription factors Sox5, Sox6 and Sox9. However, in skate, transcriptional features of developing cartilage persist into adulthood, both in peripheral chondrocytes and in cells of the fibrous perichondrium that ensheaths the skeleton. Using pulse-chase label retention experiments and multiplexed in situ hybridization, we identify a population of cycling Sox5/6/9+ perichondral progenitor cells that generate new cartilage during adult growth, and we show that persistence of chondrogenesis in adult skates correlates with ability to spontaneously repair cartilage injuries. Skates therefore offer a unique model for adult chondrogenesis and cartilage repair and may serve as inspiration for novel cell-based therapies for skeletal pathologies, such as osteoarthritis.The authors acknowledge Dr. Kate Rawlinson, Prof. Brian Hall, Dr. Kate Criswell, Dr. Victoria Sleight, Christine Hirschberger and Jenaid Rees for a collective many years of helpful discussion around the topic of cartilage development and repair, Janice Simmons, Dan Calzarette, Scott Bennett, David Remsen and the staff of the Marine Biological Laboratory Marine Resources Center for expert assistance with animal maintenance and care, and Helen Skelton (Dept. of Pathology, University of Cambridge) and Debbie Sabin (Dept. of Veterinary Medicine, University of Cambridge) for assistance with adult skate tissue processing. This work was funded by the Wellcome Trust (PhD studentship 102175/Z/13/Z to AM), the Royal Society (University Research Fellowships UF130182 and URF/R/191007 and Research Fellows Enhancement Award RGF\EA\180087 to JAG), the Isaac Newton Trust (award 14.23z to JAG) and by a research grant from the Fisheries Society of the British Isles (to JAG)

Histological evaluation of five suture materials in the telson ligament of the American horseshoe crab (Limulus polyphemus)

An ideal suture material supports healing, minimizes inflammation, and decreases the likelihood of secondary infection. While there are published recommendations for suture materials in some invertebrates, there are no published recommendations for Limulus polyphemus or any chelicerate. This study evaluates the histological reaction of horseshoe crabs to five commonly used suture materials: monofilament nylon, silk, poliglecaprone, polydioxanone, and polyglycolic acid. None of the materials were superior with regards to holding nor was there any dehiscence. Nylon evoked the least amount of tissue reaction. This work also provides a histopathological description of the soft membrane at the hinge area between the opisthosoma and telson (telson ligament) and comments on euthanasia with intracardiac eugenol