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Drake PM, Franz-Odendaal TA. Hydrocortisone treatment as a tool to study conjunctival placode induction. Dev Dyn 2024. [PMID: 39096180 DOI: 10.1002/dvdy.729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 06/27/2024] [Accepted: 07/10/2024] [Indexed: 08/05/2024] Open
Abstract
BACKGROUND Conjunctival placodes are a series of placodes that develop into the conjunctival (scleral) papillae and ultimately induce a series of scleral ossicles in the eyes of many vertebrates. This study establishes a hydrocortisone injection procedure (incl. dosage) that consistently inhibits all conjunctival papillae in the embryonic chicken eye. The effects of this hydrocortisone treatment on apoptosis, vasculature, and placode-related gene expression were assessed. RESULTS Hydrocortisone treatment does not increase apoptotic cell death or have a major effect on the ciliary artery or vascular plexus in the eye. β-catenin and Eda expression levels were not significantly altered following hydrocortisone treatment, despite the absence of conjunctival papillae. Notably, Fgf20 expression was significantly reduced following hydrocortisone treatment, and the distribution of β-catenin was altered. CONCLUSIONS Our study showed that conjunctival papillae induction begins as early as HH27.5 (E5.5). Hydrocortisone treatment reduces Fgf20 expression independently of β-catenin and Eda and may instead affect other members of the Wnt/β-catenin or Eda/Edar pathways, or it may affect the ability of morphogens to diffuse through the extracellular matrix. This study contributes to a growing profile of gene expression data during placode development and enhances our understanding of how some vertebrate eyes develop these fascinating bones.
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Affiliation(s)
- Paige M Drake
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
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Boyda-Andrade S, Silva DN, Raposo AC, Estrela-Lima A, Oriá AP. Morphobiometry of the scleral ossicle rings in Chelonia mydas sea turtles. Vet Ophthalmol 2024; 27:17-29. [PMID: 36872572 DOI: 10.1111/vop.13082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 03/07/2023]
Abstract
OBJECTIVE Scleral ossicle rings of reptiles have endoskeletal functions that are not completely understood. Moreover, descriptive reports on the anatomy of those rings are scarce. We tried to make an anatomical description that could contribute to a better understanding of their functions. ANIMAL STUDIED AND PROCEDURES We quantified, histologically characterized and evaluated the morphobiometry of the scleral ossicles, and measured the aditus orbitae of 25 sea turtle (Chelonia mydas) heads. RESULTS The aditus orbitae represented about one-third of the total head length and the mean area of the internal opening of each ring was up to 8.37% of the aditus orbitae area. The mean internal diameter of the rings (6.32 mm) was characteristic of scotopic species and the most frequent number of ossicles per ring varied between 11 and 12. Two new classifications were proposed for the ossicle types: plus-Verzahnung (+V) and minus-Verzahnung (-V). The bone tissue revealed a lamellar arrangement typical of compact and resistant bones. CONCLUSION The obtained data may be used to support and expand the understanding of functions, animal activity patterns, distinctions between taxa and taphonomic interpretations.
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Affiliation(s)
- Stelamares Boyda-Andrade
- School of Veterinary Medicine, Federal University from the West of Bahia, UFOB, Salvador, Bahia, Brazil
- School of Veterinary Medicine and Zootechny, Federal University of Bahia, UFBA, Salvador, Bahia, Brazil
| | - Danielle Nascimento Silva
- School of Veterinary Medicine and Zootechny, Federal University of Bahia, UFBA, Salvador, Bahia, Brazil
| | - Ana Cláudia Raposo
- School of Veterinary Medicine and Zootechny, Federal University of Bahia, UFBA, Salvador, Bahia, Brazil
| | - Alessandra Estrela-Lima
- School of Veterinary Medicine and Zootechny, Federal University of Bahia, UFBA, Salvador, Bahia, Brazil
| | - Arianne P Oriá
- School of Veterinary Medicine and Zootechny, Federal University of Bahia, UFBA, Salvador, Bahia, Brazil
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Koch A, Kirschbaum F, Moritz T. Ontogeny reveals the origin of Gemminger bones in Mormyridae. J Anat 2023; 243:1024-1030. [PMID: 37491873 PMCID: PMC10641036 DOI: 10.1111/joa.13935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/27/2023] Open
Abstract
Mormyridae are well known and intensively studied for their weak electric organ discharges, which facilitate communication and orientation. The Gemminger bones of Mormyridae are located next to the electrical organ in the caudal peduncle; however, they have not attracted much interest until recently. Therefore, we investigated the diversity of Gemminger bones in mormyrids and studied their ontogenetic development in Mormyrus rume proboscirostris. Gemminger bones are paired, thin, elongated ossifications lying on the dorsal and ventral sides of the caudal peduncle, and usually reach anterior well below the dorsal and anal fin bases. Ontogeny revealed that they are not intermuscular ossifications, as suspected based on the anatomical position of this structure and the systematic position of the mormyrids. Instead, they are membrane ossifications that originate from the fin stays of the dorsal and anal fins.
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Affiliation(s)
- Ann‐Katrin Koch
- Deutsches MeeresmuseumStralsundGermany
- Institute of Biological SciencesUniversity RostockRostockGermany
| | - Frank Kirschbaum
- Faculty of Life ScienceHumboldt‐University zu BerlinBerlinGermany
| | - Timo Moritz
- Deutsches MeeresmuseumStralsundGermany
- Institute of Biological SciencesUniversity RostockRostockGermany
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Franz-Odendaal TA. The elusive scleral cartilages: Comparative anatomy and development in teleosts and avians. Anat Rec (Hoboken) 2023. [PMID: 37943147 DOI: 10.1002/ar.25345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 10/04/2023] [Accepted: 10/16/2023] [Indexed: 11/10/2023]
Abstract
The sclera of all vertebrate eyes is comprised of connective tissue, with some organisms developing cartilage within this tissue. A review of the cartilages that have been described in the vertebrate sclera and their anatomical relationships is discussed together with their potential homology. Incorrect terminology erroneously implies similarity in location, development, morphology, and evolution, which may lead some scientists to assume all cartilages in orbit are the same elements when reading the literature. Therefore, new terminology to distinguish the different types of cartilage associated with the vertebrate eye is proposed. The scleral cartilages that are likely homologous to one another and which are situated in the sclera, should be termed scleral cartilages sensu stricto, while other cartilages in the sclera should be termed ocular cartilages. Some of the cartilages also ossify, and these bones should be distinguished from the scleral ossicles. The plasticity of the scleral tissue layer and its range of morphologies from fibrous to cartilaginous connective tissue across different vertebrate lineages are also described. This review also highlights several gaps in our understanding of the vertebrate scleral cartilages, in particular.
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Teodoro TG, Campos MES, Silva LA, Watanabe TT, Alves CEF, Laufer-Amorim R, Wouters F, Wouters AT. Characterization of nonpathological intrascleral cartilage in the domestic sheep (Ovis aries). PESQUISA VETERINÁRIA BRASILEIRA 2023. [DOI: 10.1590/1678-5150-pvb-7142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
ABSTRACT: Birds, cartilaginous and teleost fish, reptiles, and some amphibians have intrascleral cartilage and/or bone; however, these are rarely reported in therian mammals. This study aimed to investigate and characterize a nonpathological formation of cartilage in the posterior sclera of sheep macroscopically, histologically, and by immunohistochemical exam (IHC). Ninety eyes from 45 domestic sheep were collected, underwent gross examination, fixed in formalin, and embedded in paraffin for the microscopical assessment. Sections with histological shreds of cartilage were selected to perform IHC to confirm the presence of cartilage. Intrascleral cartilage was detected in 60 eyeballs (66.66%) from 37 sheep (82.22%). A slight whitish thickening was grossly seen in the posterior sclera. The histologic exam revealed a few scattered, isolated chondrocytes to larger aggregates of cartilaginous islands in the posterior sclera. Eighteen (30%) of 60 eyeballs revealed marked anti-collagen type II immunolabeling. The development of cartilaginous structures in the eyes is considered rare in mammalian animals. The high occurrence of intrascleral cartilage in the examined sheep eyes suggests that this finding corresponds to an anatomical component of sheep sclera, despite the age, breed, or body condition.
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Mendonça JDS, Hirano LQL, Santos ALQ, de Melo E Silva D, de Castro Pereira C, Costa MS, de Lima PN, Araújo APDC, Malafaia G, Ambrósio IS, de Moura Bife Castilho L, Dos Santos ALR, de Faria AM, de Andrade DV, Vieira LG. The exposure in ovo of embryos belonging to Amazonian turtle species Podocnemis expansa (Testudines) to commercial glyphosate and fipronil formulations impairs their growth and changes their skeletal development. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 842:156709. [PMID: 35718176 DOI: 10.1016/j.scitotenv.2022.156709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/09/2022] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
Pesticides are widely used in agricultural production; moreover, they can have direct and indirect effect on both flora and fauna. Aquatic organisms, among other animals, including reptiles, are mainly susceptible to contamination effects. Accordingly, the aim of the present study is to test the hypothesis that the incubation of Podocnemis expansa eggs in substrate added with glyphosate and fipronil formulations changes their viability, interferes with their growth and induces bone alterations. Eggs collected in natural environment were artificially incubated in sand moistened with water added with glyphosate Atar 48, at concentrations of 65 or 6500 μg/L (groups G1 and G2, respectively), and with fipronil Regent 800 WG at 4 or 400 μg/L (groups F1 and F2, respectively) or, yet, with the combination of 65 μg/L glyphosate and 4 μg/L fipronil, or with 6500 μg/L glyphosate and 400 μg/L fipronil (groups GF1 and GF2, respectively). The level of exposure to the herein assessed pesticides was quantified at the end of the incubation period; it was done by dosing its concentration in eggshells. Eggs exposed to the tested pesticides did not have their viability affected by it; however, all embryos exposed to the tested pesticides showed lowered body mass at hatch, as well as impaired development. In addition, bone malformation in the scleral ossicular ring was observed in individuals in groups F1, F2 and GF1. Pesticides accumulated in eggshells at concentrations related to exposure level. Thus, the recorded results have evidenced some remarkably relevant, and previously unknown, impacts associated with the exposure of a species listed as lower risk/conservation dependent, which spends most of its life in the water, to two widely used pesticides, at a very sensitive stage of its life, namely: egg incubation on land.
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Affiliation(s)
- Juliana Dos Santos Mendonça
- Programa de Pós-Graduação em Ecologia, Evolução e Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Rio Claro, SP, Brazil.
| | - Líria Queiroz Luz Hirano
- Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília (UNB), Brasília, DF, Brazil
| | - André Luiz Quagliatto Santos
- Laboratório de Ensino e Pesquisa em Animais Silvestres, Universidade Federal de Uberlândia (UFU), Uberlândia, MG, Brazil
| | - Daniela de Melo E Silva
- Laboratório de Genética e Mutagênese, Instituto de Ciências Biológicas, Universidade Federal de Goiás (UFG), Goiânia, GO, Brazil
| | - Carolina de Castro Pereira
- Laboratório Multidisciplinar em Morfologia e Ontogenia, Instituto de Ciências Biológicas, Universidade Federal de Goiás (UFG), Goiânia, GO, Brazil
| | - Matheus Santos Costa
- Laboratório Multidisciplinar em Morfologia e Ontogenia, Instituto de Ciências Biológicas, Universidade Federal de Goiás (UFG), Goiânia, GO, Brazil
| | - Phâmella Neres de Lima
- Laboratório Multidisciplinar em Morfologia e Ontogenia, Instituto de Ciências Biológicas, Universidade Federal de Goiás (UFG), Goiânia, GO, Brazil
| | - Amanda Pereira da Costa Araújo
- Laboratório de Toxicologia Amplicada ao Meio Ambiente, Programa de Pós-Graduação em Conservação dos Recursos Naturais do Cerrado, Instituto Federal Goiano - Campus Urutaí, GO, Brazil; Programa de Pós-Graduação em Ciências Ambientais, Universidade Federal de Goiás (UFG), Goiânia, GO, Brazil
| | - Guilherme Malafaia
- Laboratório de Toxicologia Amplicada ao Meio Ambiente, Programa de Pós-Graduação em Conservação dos Recursos Naturais do Cerrado, Instituto Federal Goiano - Campus Urutaí, GO, Brazil; Programa de Pós-Graduação em Biotecnologia e Biodiversidade, Instituição Federal Goiano e Universidade Federal de Goiás, GO, Brazil; Programa de Pós-Graduação em Ecologia, Conservação e Biodiversidade, Universidade Federal de Uberlândia (UFU), Uberlândia, MG, Brazil
| | - Isabela Sayuri Ambrósio
- Instituto de Ciências Exatas e Naturais do Pontal, Universidade Federal de Uberlândia (UFU), Ituiutaba, MG, Brazil
| | - Lais de Moura Bife Castilho
- Instituto de Ciências Exatas e Naturais do Pontal, Universidade Federal de Uberlândia (UFU), Ituiutaba, MG, Brazil
| | | | - Anizio Marcio de Faria
- Instituto de Ciências Exatas e Naturais do Pontal, Universidade Federal de Uberlândia (UFU), Ituiutaba, MG, Brazil
| | - Denis Vieira de Andrade
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Rio Claro, SP, Brazil
| | - Lucélia Gonçalves Vieira
- Laboratório Multidisciplinar em Morfologia e Ontogenia, Instituto de Ciências Biológicas, Universidade Federal de Goiás (UFG), Goiânia, GO, Brazil
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Zinck NW, Franz-Odendaal TA. Quantification and comparison of teleost scleral cartilage development and growth. J Anat 2022; 241:1014-1025. [PMID: 36574601 PMCID: PMC9482698 DOI: 10.1111/joa.13727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 12/31/2022] Open
Abstract
The ocular skeleton is composed of the scleral cartilage and the scleral ossicles. Teleost scleral cartilage is composed of a single layer of chondrocytes embedded in the sclera of the eye. The teleost scleral cartilage ring can vary in depth across teleost families and species, from a narrow ring a few cells wide to a deeper ring that resembles a cup and surrounds the entire sclera. However, very little research has been conducted on the development and morphology of teleost scleral cartilage. Thus, this study aims to characterize the development of the scleral cartilage in the zebrafish and Mexican tetra, with respect to the timing of emergence, depth throughout development, and positioning within the eye. We hypothesized that the scleral cartilage would first emerge in the scleral tissue closely abutting the ora serrata, and that growth would proceed in an anterior-to-posterior direction, resulting in differences in scleral cartilage depth between different fish species. We found that the scleral cartilage ring does not develop uniformly along its circumference, and that its relationship to the ora serrata varies between the rostral and caudal regions. Furthermore, distinct differences in the growth trajectory of the scleral cartilage indicate that the deep scleral cartilage of the Pachón cavefish is the result of both decreased eye size and prolonged cartilage growth. A significant difference in the size of the scleral chondrocytes was also noted. Overall, this study provides the first characterization of early scleral cartilage development in teleost fish and indicates that some aspects of scleral cartilage development and morphology are highly conserved while others are not.
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Affiliation(s)
- Nicholas W Zinck
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Biology, Mount Saint Vincent University, Halifax, Nova Scotia, Canada
| | - Tamara A Franz-Odendaal
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Biology, Mount Saint Vincent University, Halifax, Nova Scotia, Canada
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Yamashita M, Tsuihiji T. The relationship between hard and soft tissue structures of the eye in extant lizards. J Morphol 2022; 283:1182-1199. [PMID: 35833614 PMCID: PMC9545706 DOI: 10.1002/jmor.21495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 11/19/2022]
Abstract
The sizes of the eye structures, such as the lens diameter and the axial length, are important factors for the visual performance and are considered to be related to the mode of life. Although the size of these soft structures cannot be directly observed in fossil taxa, such information may be obtained from measuring size and morphology of the bony scleral ossicle ring, which is present in the eyes of extant saurospids, excluding crocodiles and snakes, and is variously preserved in fossil taxa. However, there have been only a few studies investigating the relationships between the size, the scleral ossicle ring, and soft structures of the eye. We investigated such relationships among the eye structures in extant Squamata, to establish the basis for inferring the size of the soft structures in the eye in fossil squamates. Three‐dimensional morphological data on the eye and head region of 59 lizard species covering most major clades were collected using micro‐computed tomography scanners. Strong correlations were found between the internal and external diameters of the scleral ossicle ring and soft structures. The tight correlations found here will allow reliable estimations of the sizes of soft structures and inferences on the visual performance and mode of life in fossil squamates, based on the diameters of their preserved scleral ossicle rings. Furthermore, the comparison of the allometric relationships between structures in squamates eyes with those in avian eyes suggest the possibility that the similarities of these structures closely reflect the mechanism of accommodation. The sizes of the eye structures are important factors for the visual performance. Strong correlations were found between the scleral ossicle ring and soft structures in extant squamates eyes. These correlations will allow reliable estimations of soft structures and inferences on the visual performance and mode of life in fossil squamates.
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Affiliation(s)
- Momo Yamashita
- Center for Collections, National Museum of Nature and Science, 4-1-1, Amakubo, Tsukuba, Ibaraki, 305-0005, Japan.,Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8567, Japan
| | - Takanobu Tsuihiji
- Department of Geology and Paleontology, National Museum of Nature and Science, 4-1-1, Amakubo, Tsukuba, Ibaraki, 305-0005, Japan.,Department of Earth and Planetary Science, The University of Tokyo, 7-3-1, Hongo, Bunkyoku, Tokyo, 113-0033, Japan
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9
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Kwok S, Pan M, Hazen N, Pan X, Liu J. Mechanical Deformation of Peripapillary Retina in Response to Acute Intraocular Pressure Elevation. J Biomech Eng 2022; 144:1131131. [PMID: 35001106 DOI: 10.1115/1.4053450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Indexed: 11/08/2022]
Abstract
Elevated intraocular pressure (IOP) may cause mechanical injuries to the optic nerve head (ONH) and the peripapillary tissues in glaucoma. Previous studies have reported the mechanical deformation of the ONH and the peripapillary sclera (PPS) at elevated IOP. The deformation of the peripapillary retina (PPR) has not been well-characterized. Here we applied high-frequency ultrasound elastography to map and quantify PPR deformation, and compared PPR, PPS and ONH deformation in the same eye. Whole globe inflation was performed in ten human donor eyes. High-frequency ultrasound scans of the posterior eye were acquired while IOP was raised from 5 to 30 mmHg. A correlation-based ultrasound speckle tracking algorithm was used to compute pressure-induced displacements within the scanned tissue cross-sections. Radial, tangential, and shear strains were calculated for the PPR, PPS, and ONH regions. In PPR, shear was significantly larger in magnitude than radial and tangential strains. Strain maps showed localized high shear and high tangential strains in PPR. In comparison to PPS and ONH, PPR had greater shear and a similar level of tangential strain. Surprisingly, PPR radial compression was minimal and significantly smaller than that in PPS. These results provide new insights into PPR deformation in response of IOP elevation, suggesting that shear rather than compression was likely the primary mode of IOP-induced mechanical insult in PPR. High shear, especially localized high shear, may contribute to the mechanical damage of this tissue in glaucoma.
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Affiliation(s)
- Sunny Kwok
- Department of Biomedical Engineering, Ohio State University, 140 W 19th Ave, Columbus, OH 43210
| | - Manqi Pan
- Department of Biomedical Engineering, Ohio State University, 140 W 19th Ave, Columbus, OH 43210
| | - Nicholas Hazen
- Biophysics Interdisciplinary Group, Ohio State University, 140 W 19th Ave, Columbus, OH 43210
| | - Xueliang Pan
- Department of Biomedical Informatics, Ohio State University, 1800 Cannon Drive, Columbus, OH 43210
| | - Jun Liu
- Department of Biomedical Engineering, Ohio State University, 140 W 19th Ave, Columbus, OH 43210
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Erratum for. J Morphol 2021; 282:1569. [PMID: 34378807 DOI: 10.1002/jmor.21406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hadden PW, Gerneke DA, McGhee CNJ, Zhang J. Skeletal elements of the penguin eye and their functional and phylogenetic implications (Aves: Sphenisciformes: Spheniscidae). J Morphol 2021; 282:874-886. [PMID: 33786885 PMCID: PMC8252517 DOI: 10.1002/jmor.21354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 01/24/2023]
Abstract
Scleral ossicles and other bony elements are present in the eyes of many vertebrates, including birds. In this study, the skeletal elements present in the penguin eye and orbit were imaged using macro photographs and micro-computed tomography (micro-CT), to help elucidate their function and significance. A total of 36 scleral rings and three whole skulls were imaged. King (Aptenodytes patagonicus), Fiordland crested (Eudyptes pachyrhynchus), Snares crested (Eudyptes robustus), royal (Eudyptes schlegeli) and yellow-eyed (Megadyptes antipodes) penguins had between 12 and 14 elements in their scleral ring while the gentoo (Pygoscelis papua) had 14 and 17; little penguins (Eudyptula sp.) consistently had between 10 and 12 elements. All had at least two elements that overlapped, usually totally, each neighbour, and two that were overlapped by each neighbour. The interior structure of all ossicles revealed a lattice-like arrangement of struts typical of cancellous bone, the whole being surrounded by thick cortical bone. The scleral ring of a 10 week gentoo chick was not completely ossified but rather had multiple small holes within it on micro-CT. A large os opticus was present in one king penguin but in another bird of the same age and gender there was no such bone. Much smaller accessory bones were found in the posterior pole of one Snares crested and one little penguin. We conclude that the penguin scleral ring not only maintains the shape of the eye but also provides protection and a site of insertion for rectus muscles. However, the extreme variability in the os opticus suggests that it is not essential to normal function.
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Affiliation(s)
- Peter W Hadden
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Dane A Gerneke
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Charles N J McGhee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Jie Zhang
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Gendron RL, Paradis H, Ahmad R, Kao K, Boyce D, Good WV, Kumar S, Vasquez I, Cao T, Hossain A, Chakraborty S, Valderrama K, Santander J. CD10 + Cells and IgM in Pathogen Response in Lumpfish ( Cyclopterus lumpus) Eye Tissues. Front Immunol 2020; 11:576897. [PMID: 33329544 PMCID: PMC7714965 DOI: 10.3389/fimmu.2020.576897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 10/22/2020] [Indexed: 11/30/2022] Open
Abstract
Lumpfish (Cyclopterus lumpus), a North Atlantic "cleaner" fish, is utilized to biocontrol salmon louse (Lepeophtheirus salmonis) in Atlantic salmon (Salmo salar) farms. Lumpfish require excellent vision to scan for and eat louse on salmon skin. The lumpfish eye immune response to infectious diseases has not been explored. We examined the ocular response to a natural parasite infection in wild lumpfish and to an experimental bacterial infection in cultured lumpfish. Cysts associated with natural myxozoan infection in the ocular scleral cartilage of wild adult lumpfish harbored cells expressing cluster of differentiation 10 (CD10) and immunoglobulin M (IgM). Experimental Vibrio anguillarum infection, which led to exophthalmos and disorganization of the retinal tissues was associated with disruption of normal CD10 expression, CD10+ cellular infiltration and IgM expression. We further describe the lumpfish CD10 orthologue and characterize the lumpfish scleral skeleton in the context of myxozoan scleral cysts. We propose that lumpfish develop an intraocular response to pathogens, exemplified herein by myxozoan and V. anguillarum infection involving novel CD10+ cells and IgM+ cells to contain and mitigate damage to eye structures. This work is the first demonstration of CD10 and IgM expressing cells in a novel ocular immune system component in response to disease in a teleost.
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Affiliation(s)
- Robert L. Gendron
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John’s, NL, Canada
| | - Hélène Paradis
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John’s, NL, Canada
| | - Raahyma Ahmad
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John’s, NL, Canada
| | - Kenneth Kao
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John’s, NL, Canada
| | - Danny Boyce
- Marine Microbial Pathogenesis and Vaccinology Lab, Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
| | - William V. Good
- Smith Kettlewell Eye Research Institute, San Francisco, CA, United States
| | - Surendra Kumar
- Marine Microbial Pathogenesis and Vaccinology Lab, Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
| | - Ignacio Vasquez
- Marine Microbial Pathogenesis and Vaccinology Lab, Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
| | - Trung Cao
- Marine Microbial Pathogenesis and Vaccinology Lab, Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
| | - Ahmed Hossain
- Marine Microbial Pathogenesis and Vaccinology Lab, Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
| | - Setu Chakraborty
- Marine Microbial Pathogenesis and Vaccinology Lab, Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
| | - Katherinne Valderrama
- Marine Microbial Pathogenesis and Vaccinology Lab, Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
| | - Javier Santander
- Marine Microbial Pathogenesis and Vaccinology Lab, Department of Ocean Sciences, Memorial University, St. John’s, NL, Canada
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Comai GE, Tesařová M, Dupé V, Rhinn M, Vallecillo-García P, da Silva F, Feret B, Exelby K, Dollé P, Carlsson L, Pryce B, Spitz F, Stricker S, Zikmund T, Kaiser J, Briscoe J, Schedl A, Ghyselinck NB, Schweitzer R, Tajbakhsh S. Local retinoic acid signaling directs emergence of the extraocular muscle functional unit. PLoS Biol 2020; 18:e3000902. [PMID: 33201874 PMCID: PMC7707851 DOI: 10.1371/journal.pbio.3000902] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 12/01/2020] [Accepted: 10/01/2020] [Indexed: 12/20/2022] Open
Abstract
Coordinated development of muscles, tendons, and their attachment sites ensures emergence of functional musculoskeletal units that are adapted to diverse anatomical demands among different species. How these different tissues are patterned and functionally assembled during embryogenesis is poorly understood. Here, we investigated the morphogenesis of extraocular muscles (EOMs), an evolutionary conserved cranial muscle group that is crucial for the coordinated movement of the eyeballs and for visual acuity. By means of lineage analysis, we redefined the cellular origins of periocular connective tissues interacting with the EOMs, which do not arise exclusively from neural crest mesenchyme as previously thought. Using 3D imaging approaches, we established an integrative blueprint for the EOM functional unit. By doing so, we identified a developmental time window in which individual EOMs emerge from a unique muscle anlage and establish insertions in the sclera, which sets these muscles apart from classical muscle-to-bone type of insertions. Further, we demonstrate that the eyeballs are a source of diffusible all-trans retinoic acid (ATRA) that allow their targeting by the EOMs in a temporal and dose-dependent manner. Using genetically modified mice and inhibitor treatments, we find that endogenous local variations in the concentration of retinoids contribute to the establishment of tendon condensations and attachment sites that precede the initiation of muscle patterning. Collectively, our results highlight how global and site-specific programs are deployed for the assembly of muscle functional units with precise definition of muscle shapes and topographical wiring of their tendon attachments.
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Affiliation(s)
- Glenda Evangelina Comai
- Stem Cells & Development Unit, Institut Pasteur, Paris, France
- CNRS UMR 3738, Institut Pasteur, Paris, France
- * E-mail: (GEC); (ST)
| | - Markéta Tesařová
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - Valérie Dupé
- Université de Rennes, CNRS, IGDR, Rennes, France
| | - Muriel Rhinn
- IGBMC-Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
| | | | - Fabio da Silva
- Université Côte d'Azur, INSERM, CNRS, iBV, Nice, France
- Division of Molecular Embryology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Betty Feret
- IGBMC-Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
| | | | - Pascal Dollé
- IGBMC-Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
| | - Leif Carlsson
- Umeå Center for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Brian Pryce
- Research Division, Shriners Hospital for Children, Portland, United States of America
| | - François Spitz
- Genomics of Animal Development Unit, Institut Pasteur, Paris, France
| | - Sigmar Stricker
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Tomáš Zikmund
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - Jozef Kaiser
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | | | | | - Norbert B. Ghyselinck
- IGBMC-Institut de Génétique et de Biologie Moleculaire et Cellulaire, Illkirch, France
| | - Ronen Schweitzer
- Research Division, Shriners Hospital for Children, Portland, United States of America
| | - Shahragim Tajbakhsh
- Stem Cells & Development Unit, Institut Pasteur, Paris, France
- CNRS UMR 3738, Institut Pasteur, Paris, France
- * E-mail: (GEC); (ST)
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Giffin JL, Franz-Odendaal TA. Quantitative gene expression dynamics of key placode signalling factors in the embryonic chicken scleral ossicle system. Gene Expr Patterns 2020; 38:119131. [PMID: 32755633 DOI: 10.1016/j.gep.2020.119131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/25/2020] [Accepted: 07/29/2020] [Indexed: 10/23/2022]
Abstract
Development of the scleral ossicles, a ring of bony elements within the sclera, is directed by a series of papillae that arise from placodes in the conjunctival epithelium over a 1.5-day induction period in the chicken embryo. The regular spacing of the papillae around the corneal-scleral limbus suggests that their induction may be regulated by a reaction-diffusion mechanism, similar to other epithelial appendages. Some key placode signalling molecules, including β-catenin, are known to be expressed throughout the induction period. However, others have been studied only at certain stages or have not been successfully detected. Here we use qPCR to study the gene expression patterns of the wingless integration (WNT)/β-catenin, bone morphogenetic protein (BMP), ectodysplasin (EDA), fibroblast growth factor (FGF) and hedgehog (HH) signalling families in discrete regions of the eye throughout the complete conjunctival placode and papillae induction period. This comprehensive analysis revealed a variable level of gene expression within specific eye regions, with some genes exhibiting high, moderate or low changes. Most genes exhibited an initial increase in gene expression, followed by a decrease or plateau as development proceeded, suggesting that some genes are important for a brief initial period whilst the sustained elevated expression level of other genes is needed for developmental progression. The timing or magnitude of these changes, and/or the overall gene expression trend differed in the temporal, nasal and/or dorsal eye regions for some, but not all genes, demonstrating that gene expression may vary across different eye regions. Temporal and nasal EDA receptor (EDAR) had the greatest number of strong correlations (r > 0.700) with other genes and β-catenin had the greatest number of moderate correlations (r = 0.400-0.700), while EDA had the greatest range in correlation strengths. Among the strongly correlated genes, two distinct signalling modules were identified, connected by some intermediate genes. The dynamic gene expression patterns of the five signalling pathways studied here from conjunctival placode formation through to papillae development is consistent with other epithelial appendages and confirms the presence of a conserved induction and patterning signalling network. Two unique gene expression patterns and corresponding gene interaction modules suggest functionally distinct roles throughout placode development. Furthermore, spatial differences in gene expression patterns among the temporal, nasal and dorsal regions of the eye may indicate that the expression of certain genes is influenced by mechanical forces exerted throughout development. Therefore, this study identifies key placode signalling factors and their interactions, as well as some potential region-specific features of gene expression in the scleral ossicle system and provides a basis for further exploration of the spatial expression of these genes and the patterning mechanism(s) active throughout conjunctival placode and papillae formation.
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Affiliation(s)
- Jennifer L Giffin
- Department of Biology, Mount Saint Vincent University, 166 Bedford Highway, Halifax, NS, B3M 2J6, Canada.
| | - Tamara A Franz-Odendaal
- Department of Biology, Mount Saint Vincent University, 166 Bedford Highway, Halifax, NS, B3M 2J6, Canada.
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15
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Franz‐Odendaal TA, Krings M. A heterochronic shift in skeletal development in the barn owl (
Tyto furcata
): A description of the ocular skeleton and tubular eye shape formation. Dev Dyn 2019; 248:671-678. [DOI: 10.1002/dvdy.65] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/04/2019] [Accepted: 05/20/2019] [Indexed: 01/08/2023] Open
Affiliation(s)
| | - Markus Krings
- Institute of Biology IIRWTH Aachen University Aachen Germany
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Giffin JL, Gaitor D, Franz-Odendaal TA. The Forgotten Skeletogenic Condensations: A Comparison of Early Skeletal Development Amongst Vertebrates. J Dev Biol 2019; 7:jdb7010004. [PMID: 30717314 PMCID: PMC6473759 DOI: 10.3390/jdb7010004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 01/24/2019] [Accepted: 01/30/2019] [Indexed: 01/13/2023] Open
Abstract
The development of a skeletogenic condensation is perhaps the most critical yet considerably overlooked stage of skeletogenesis. Described in this comprehensive review are the mechanisms that facilitate skeletogenic condensation formation, growth, and maintenance to allow for overt differentiation into a skeletal element. This review discusses the current knowledge of gene regulation and characterization of skeletogenic condensations in the chicken, mouse, zebrafish, and other developmental models. We limited our scope to condensations that give rise to the bones and cartilages of the vertebrate skeleton, with a particular focus on craniofacial and limb bud regions. While many of the skeletogenic processes are similar among vertebrate lineages, differences are apparent in the site and timing of the initial epithelial⁻mesenchymal interactions as well as in whether the condensation has an osteogenic or chondrogenic fate, both within and among species. Further comparative studies are needed to clarify and broaden the existing knowledge of this intricate phenomenon.
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Affiliation(s)
- Jennifer L Giffin
- Department of Biology, Mount Saint Vincent University, 166 Bedford Highway, Halifax, NS B3M 2J6, Canada.
| | - Danielle Gaitor
- Department of Biology, Mount Saint Vincent University, 166 Bedford Highway, Halifax, NS B3M 2J6, Canada.
- Department of Medical Neuroscience, Dalhousie University, 5850 College Street, Halifax, NS B3H 4R2, Canada.
| | - Tamara A Franz-Odendaal
- Department of Biology, Mount Saint Vincent University, 166 Bedford Highway, Halifax, NS B3M 2J6, Canada.
- Department of Medical Neuroscience, Dalhousie University, 5850 College Street, Halifax, NS B3H 4R2, Canada.
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Franz-Odendaal TA. Skeletons of the Eye: An Evolutionary and Developmental Perspective. Anat Rec (Hoboken) 2018; 303:100-109. [PMID: 30548203 DOI: 10.1002/ar.24043] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/27/2018] [Accepted: 05/12/2018] [Indexed: 11/10/2022]
Abstract
The ocular skeleton, composed of the scleral cartilage and scleral ossicles, is present in many vertebrates. The morphology of the scleral cartilage and ossicles varies within different extant reptiles (including birds) and also varies dramatically from the morphology in extant teleosts. This incredible range of diverse morphologies is the result of millions of years of evolution. Both the position of these elements within the eye and the timing of development vary amongst different vertebrates. While the development of both the scleral cartilage and scleral ossicles is somewhat understood in reptiles and in teleosts, the functional advantage of these elements is still debated. Most reptiles have a multi-component scleral ossicle ring composed of a series of flat bone plates and a scleral cartilage cup lining the retina, some sharks have calcified cartilage plates, and some teleosts have two bones while most others only have a ring of scleral cartilage. The data presented shows that different vertebrates have adapted to similar selective pressures in different ways. However, the reason why sarcopterygians have a series of overlapping bones in the sclera remains unclear. A better understanding of the ocular skeletal diversity in Reptilia as well as a better understanding of the mechanisms of vision within different environments (i.e., air vs. water) and that used by secondarily aquatic organisms is needed. This review discusses the observed variation in morphology and development of the ocular skeleton in the context of evolution and highlights our knowledge gaps in these areas. Anat Rec, 2018. © 2018 American Association for Anatomy.
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18
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Kumar S, Franz-Odendaal TA. Analysis of the FGFR spatiotemporal expression pattern within the chicken scleral ossicle system. Gene Expr Patterns 2018; 30:7-13. [DOI: 10.1016/j.gep.2018.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 08/20/2018] [Accepted: 08/21/2018] [Indexed: 12/26/2022]
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19
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Hammer CL, Franz-Odendaal TA. Towards understanding the dose and timing effect of hydrocortisone treatment on the scleral ossicle system within the chicken eye. J Anat 2017; 232:270-282. [PMID: 29210090 DOI: 10.1111/joa.12744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2017] [Indexed: 10/18/2022] Open
Abstract
Previous work, almost four decades ago, showed that hydrocortisone (HC) treatment reduces the number of skeletogenic condensations that give rise to the scleral ossicles in the chicken eye. The scleral ossicles are a ring of overlapping intramembranous bones, the sclerotic ring, and are present in most reptiles, including birds. The scleral condensations that give rise to the scleral ossicles are induced by a series of overlying thickenings (or papillae) of the conjunctival epithelium. Here, we further explore the effects of altering the dosage and timing of HC treatment on the morphology and number of skeletogenic condensations and conjunctival papillae. We show that high doses can completely obliterate the entire sclerotic ring. Significantly, the reduction in papillae number we observed was less extreme than that of the scleral condensations, indicating that additional factors contribute to the observed skeletogenic condensation loss. Via immunohistochemical analyses, we show that HC treatment alters the spatial expression pattern of several extracellular matrix components (tenascin-C, decorin and procollagen I) and also alters the vasculature network within the sclera. This research provides important insights into understanding the role of the scleral tissue components in ossicle development within the vertebrate eye.
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Chevrinais M, Sire JY, Cloutier R. Unravelling the ontogeny of a Devonian early gnathostome, the "acanthodian" Triazeugacanthus affinis (eastern Canada). PeerJ 2017; 5:e3969. [PMID: 29094000 PMCID: PMC5661438 DOI: 10.7717/peerj.3969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/08/2017] [Indexed: 12/01/2022] Open
Abstract
The study of vertebrate ontogenies has the potential to inform us of shared developmental patterns and processes among organisms. However, fossilised ontogenies of early vertebrates are extremely rare during the Palaeozoic Era. A growth series of the Late Devonian “acanthodian” Triazeugacanthus affinis, from the Miguasha Fossil-Fish Lagerstätte, is identified as one of the best known early vertebrate fossilised ontogenies given the exceptional preservation, the large size range, and the abundance of specimens. Morphological, morphometric, histological and chemical data are gathered on a growth series of Triazeugacanthus ranging from 4 to 52 mm in total length. The developmental trajectory of this Devonian “acanthodian” is characteristic of fishes showing a direct development with alternating steps and thresholds. Larvae show no squamation but a progressive appearance of cartilaginous neurocranial and vertebral elements, and appendicular elements, whereas juveniles progress in terms of ossification and squamation. The presence of cartilaginous and bony tissues, discriminated on histological and chemical signatures, shows a progressive mineralisation of neurocranial and vertebral elements. Comparison among different body proportions for larvae, juveniles and adults suggest allometric growth in juveniles. Because of the phylogenetic position of “acanthodians”, Triazeugacanthus ontogeny informs us about deep time developmental conditions in gnathostomes.
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Affiliation(s)
- Marion Chevrinais
- Laboratoire de Paléontologie et Biologie évolutive, Université du Québec à Rimouski, Rimouski, Canada
| | - Jean-Yves Sire
- CNRS-UMR 7138-Evolution Paris-Seine IBPS, Université Pierre et Marie Curie, Paris, France
| | - Richard Cloutier
- Laboratoire de Paléontologie et Biologie évolutive, Université du Québec à Rimouski, Rimouski, Canada
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Jourdeuil K, Franz-Odendaal TA. A wide temporal window for conjunctival papillae development ensures the formation of a complete sclerotic ring. Dev Dyn 2017; 246:381-391. [PMID: 28152584 DOI: 10.1002/dvdy.24489] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 01/12/2017] [Accepted: 01/26/2017] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND The conjunctival papillae are epithelial thickenings of the conjunctiva that are required for the induction of underlying bones (the scleral ossicles). These transient papillae develop and become inductively active over an extended temporal period (HH 30-36, 6.5-10 dpf). While their inductive capacity was discovered in the mid-1900s, little is known about their development. RESULTS Through a series of timed surgical ablations followed by in situ hybridization for Bmp2, we show that the ring of conjunctival papillae is not altered if the conjunctival epithelium is ablated either prior to or shortly after papillae induction (i.e., HH 29-30, 6.5-7 dpf). A conjunctival papilla ablated at or prior to HH 34 (8 dpf), when the complete ring is present, regenerates and quickly becomes inductively active, inducing an underlying scleral condensation with only a slight delay. This regenerative capacity extends until HH 35.5, a full 36 hours beyond the normal timeline of papillae induction. As such, the period of epithelial competency for papilla induction is longer than previously identified. CONCLUSIONS Papilla regeneration is a mechanism that ensures the formation of a complete sclerotic ring and provides another level of redundancy for the induction of a complete sclerotic ring during the normal inductive period. Developmental Dynamics 246:381-391, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Karyn Jourdeuil
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada.,Department of Biology, Mount Saint Vincent University, Halifax, NS, Canada
| | - Tamara Anne Franz-Odendaal
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada.,Department of Biology, Mount Saint Vincent University, Halifax, NS, Canada
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Lyon A, Powers AK, Gross JB, O’Quin KE. Two - three loci control scleral ossicle formation via epistasis in the cavefish Astyanax mexicanus. PLoS One 2017; 12:e0171061. [PMID: 28182695 PMCID: PMC5300192 DOI: 10.1371/journal.pone.0171061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 01/16/2017] [Indexed: 11/28/2022] Open
Abstract
The sclera is the protective outer layer of the eye. In fishes, birds, and reptiles, the sclera may be reinforced with additional bony elements called scleral ossicles. Teleost fish vary in the number and size of scleral ossicles; however, the genetic mechanisms responsible for this variation remain poorly understood. In this study, we examine the inheritance of scleral ossicles in the Mexican tetra, Astyanax mexicanus, which exhibits both a cave morph and a surface fish morph. As these morphs and their hybrids collectively exhibit zero, one, and two scleral ossicles, they represent a microcosm of teleost scleral ossicle diversity. Our previous research in F2 hybrids of cavefish from Pachón cave and surface fish from Texas suggested that three genes likely influence the formation of scleral ossicles in this group through an epistatic threshold model of inheritance, though our sample size was small. In this study, we expand our sample size using additional hybrids of Pachón cavefish and Mexican surface fish to (1) confirm the threshold model of inheritance, (2) refine the number of genes responsible for scleral ossicle formation, and (3) increase our power to detect quantitative trait loci (QTL) for this trait. To answer these three questions, we scored surface fish and cavefish F2 hybrids for the presence of zero, one, or two scleral ossicles. We then analyzed their distribution among the F2 hybrids using a chi-square (χ2) test, and used a genetic linkage map of over 100 microsatellite markers to identify QTL responsible for scleral ossicle number. We found that inheritance of scleral ossicles follows an epistatic threshold model of inheritance controlled by two genes, which contrasts the three-locus model estimated from our previous study. Finally, the combined analysis of hybrids from both crosses identified two strong QTL for scleral ossicle number on linkage groups 4.2 and 21, and a weaker QTL on linkage group 4.1. Scleral ossification remains a complex trait with limited knowledge of its genetic basis. This study provides new insight into the number and location of genes controlling the formation of scleral ossicles in a teleost fish species.
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Affiliation(s)
- Anastasia Lyon
- Biology Program, Centre College, Danville, KY, United States of America
| | - Amanda K. Powers
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States of America
| | - Joshua B. Gross
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States of America
| | - Kelly E. O’Quin
- Biology Program, Centre College, Danville, KY, United States of America
- * E-mail:
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Tusler CA, Good KL, Maggs DJ, Zwingenberger AL, Reilly CM. Gross, histologic, and computed tomographic characterization of nonpathological intrascleral cartilage and bone in the domestic goat (Capra aegagrus hircus). Vet Ophthalmol 2016; 20:214-221. [DOI: 10.1111/vop.12391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Charlotte A. Tusler
- Veterinary Medical Teaching Hospital; School of Veterinary Medicine; University of California; Davis CA 95616 USA
| | - Kathryn L. Good
- Department of Surgical & Radiological Sciences; School of Veterinary Medicine; University of California; Davis CA 95616 USA
| | - David J. Maggs
- Department of Surgical & Radiological Sciences; School of Veterinary Medicine; University of California; Davis CA 95616 USA
| | - Allison L. Zwingenberger
- Department of Surgical & Radiological Sciences; School of Veterinary Medicine; University of California; Davis CA 95616 USA
| | - Christopher M. Reilly
- Department of Pathology, Microbiology & Immunology; School of Veterinary Medicine; University of California; Davis CA 95616 USA
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New Insights in the Ontogeny and Taphonomy of the Devonian Acanthodian Triazeugacanthus affinis From the Miguasha Fossil-Lagerstätte, Eastern Canada. MINERALS 2015. [DOI: 10.3390/min6010001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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25
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Complex Evolutionary and Genetic Patterns Characterize the Loss of Scleral Ossification in the Blind Cavefish Astyanax mexicanus. PLoS One 2015; 10:e0142208. [PMID: 26649887 PMCID: PMC4674125 DOI: 10.1371/journal.pone.0142208] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 10/19/2015] [Indexed: 12/21/2022] Open
Abstract
The sclera is the tough outer covering of the eye that provides structural support and helps maintain intraocular pressure. In some fishes, reptiles, and birds, the sclera is reinforced with an additional ring of hyaline cartilage or bone that forms from scleral ossicles. Currently, the evolutionary and genetic basis of scleral ossification is poorly understood, especially in teleost fishes. We assessed scleral ossification among several groups of the Mexican tetra (Astyanax mexicanus), which exhibit both an eyed and eyeless morph. Although eyed Astyanax surface fish have bony sclera similar to other teleosts, the ossicles of blind Astyanax cavefish generally do not form. We first sampled cavefish from multiple independent populations and used ancestral character state reconstructions to determine how many times scleral ossification has been lost. We then confirmed these results by assessing complementation of scleral ossification among the F1 hybrid progeny of two cavefish populations. Finally, we quantified the number of scleral ossicles present among the F2 hybrid progeny of a cross between surface fish and cavefish, and used this information to identify quantitative trait loci (QTL) responsible for this trait. Our results indicate that the loss of scleral ossification is common-but not ubiquitous-among Astyanax cavefish, and that this trait has been convergently lost at least three times. The presence of wild-type, ossified sclera among the F1 hybrid progeny of a cross between different cavefish populations confirms the convergent evolution of this trait. However, a strongly skewed distribution of scleral ossicles found among surface fish x cavefish F2 hybrids suggests that scleral ossification is a threshold trait with a complex genetic basis. Quantitative genetic mapping identified a single QTL for scleral ossification on Astyanax linkage group 1. We estimate that the threshold for this trait is likely determined by at least three genetic factors which may control the severity and onset of lens degeneration in cavefishes. We conclude that complex evolutionary and genetic patterns underlie the loss of scleral ossification in Astyanax cavefish.
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Xiong Z, Jiang R, Zhang P, Han X, Guo FJ. Transmission of ER stress response by ATF6 promotes endochondral bone growth. J Orthop Surg Res 2015; 10:141. [PMID: 26374329 PMCID: PMC4571128 DOI: 10.1186/s13018-015-0284-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/31/2015] [Indexed: 01/15/2023] Open
Abstract
Background We reported earlier that X-box binding protein1 spliced (XBP1S), a key regulator of the unfolded protein response (UPR), as a bone morphogenetic protein 2 (BMP2)-inducible transcription factor, positively regulates endochondral bone formation by activating granulin-epithelin precursor (GEP) chondrogenic growth factor. Under the stress of misfolded or unfolded proteins in the endoplasmic reticulum (ER), the cells can be protected by the mammalian UPR. However, the influence of activating transcription factor 6 (ATF6), another transcriptional arm of UPR, in BMP2-induced chondrocyte differentiation has not yet been elucidated. In the current study, we investigate and explore the role of ATF6 in endochondral bone formation, focus on associated molecules of hypertrophic chondrocyte differentiation, as well as the molecular events underlying this process. Methods High-cell-density micromass cultures were used to induce ATDC5 and C3H10T1/2 cell differentiation into chondrocytes. Quantitative real-time PCR, immunoblotting analysis, and immunohistochemistry were performed to examine (1) the expression of ATF6, ATF6α, collagen II, collagen X, and matrix metalloproteinase-13 (MMP13) and (2) whether ATF6 stimulates chondrogenesis and whether ATF6 enhances runt-related transcription factor 2 (Runx2)-mediated chondrocyte hypertrophy. Culture of fetal mouse bone explants was to detect whether ATF6 stimulates chondrocyte hypertrophy, mineralization, and endochondral bone growth. Coimmunoprecipitation was employed to determine whether ATF6 associates with Runx2 in chondrocyte differentiation. Results ATF6 is differentially expressed in the course of BMP2-triggered chondrocyte differentiation. Overexpression of ATF6 accelerates chondrocyte differentiation, and the ex vivo studies reveal that ATF6 is a potent stimulator of chondrocyte hypertrophy, mineralization, and endochondral bone growth. Knockdown of ATF6 via a siRNA approach inhibits chondrogenesis. Furthermore, ATF6 associates with Runx2 and enhances Runx2-induced chondrocyte hypertrophy. And, the stimulation effect of ATF6 is reduced during inhibition of Runx2 via a siRNA approach, suggesting that the promoting effect is required for Runx2. Conclusions Our observations demonstrate that ATF6 positively regulates chondrocyte hypertrophy and endochondral bone formation through activating Runx2-mediated hypertrophic chondrocyte differentiation.
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Affiliation(s)
- Zhangyuan Xiong
- Department of Cell Biology and Genetics, Core Facility of Development Biology, Chongqing Medical University, Chongqing, 400016, China
| | - Rong Jiang
- Laboratory of Stem Cells and Tissue Engineering, Chongqing Medical University, Chongqing, China
| | - Peng Zhang
- Department of Cell Biology and Genetics, Core Facility of Development Biology, Chongqing Medical University, Chongqing, 400016, China
| | - Xiaofeng Han
- Department of Cell Biology and Genetics, Core Facility of Development Biology, Chongqing Medical University, Chongqing, 400016, China
| | - Feng-Jin Guo
- Department of Cell Biology and Genetics, Core Facility of Development Biology, Chongqing Medical University, Chongqing, 400016, China.
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Vascular endothelial growth factor signaling affects both angiogenesis and osteogenesis during the development of scleral ossicles. Dev Biol 2015. [PMID: 26210172 DOI: 10.1016/j.ydbio.2015.07.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Intramembranous ossification is a complex multi-step process which relies on extensive interactions among bone cells and surrounding tissues. The embryonic vasculature is essential in regulating endochondral ossification; however, its role during intramembranous ossification remains poorly understood, and in vivo studies are lacking. Previous research from our lab on the development of the intramembranous scleral ossicles has demonstrated an intriguing pattern of vascular development in which the areas of future osteogenesis remain avascular until after bone induction has occurred. Such avascular zones are located directly beneath each of the conjunctival papillae, epithelial structures which provide osteogenic signals to the underlying mesenchyme. Here we provide a high-resolution map of the developing vasculature from the time of ossicle induction to mineralization using a novel technique. We show that vegfa is expressed by the papillae and nearby mesenchymal tissue throughout HH 34-37, when vascular growth is taking place, and is down-regulated thereafter. Localized inhibition of Vegf results in expansion of the avascular zone surrounding the implanted papilla and mispatterning of the scleral ossicles. These results demonstrate that Vegf signaling could provide important insights into the complex relationship between bone and vasculature during intramembranous bone development.
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Sclerotic rings in mosasaurs (Squamata: Mosasauridae): structures and taxonomic diversity. PLoS One 2015; 10:e0117079. [PMID: 25692667 PMCID: PMC4334958 DOI: 10.1371/journal.pone.0117079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 12/19/2014] [Indexed: 11/19/2022] Open
Abstract
Mosasaurs (Squamata: Mosasauridae) were a highly diverse, globally distributed group of aquatic lizards in the Late Cretaceous (98–66 million years ago) that exhibited a high degree of adaptation to life in water. To date, despite their rich fossil record, the anatomy of complete mosasaur sclerotic rings, embedded in the sclera of the eyeball, has not been thoroughly investigated. We here describe and compare sclerotic rings of four mosasaur genera, Tylosaurus, Platecarpus, Clidastes, and Mosasaurus, for the first time. Two specimens of Tylosaurus and Platecarpus share an exact scleral ossicle arrangement, excepting the missing portion in the specimen of Platecarpus. Furthermore, the exact arrangement and the total count of 14 ossicles per ring are shared between Tylosaurus and numerous living terrestrial lizard taxa, pertaining to both Iguania and Scleroglossa. In contrast, two species of Mosasaurus share the identical count of 12 ossicles and the arrangement with each other, while no living lizard taxa share exactly the same arrangement. Such a mosaic distribution of these traits both among squamates globally and among obligatorily aquatic mosasaurs specifically suggests that neither the ossicle count nor their arrangement played major roles in the aquatic adaptation in mosasaur eyes. All the mosasaur sclerotic rings examined consistently exhibit aperture eccentricity and the scleral ossicles with gently convex outer side. Hitherto unknown to any squamate taxa, one specimen of Platecarpus unexpectedly shows a raised, concentric band of roughened surface on the inner surface of the sclerotic ring. It is possible that one or both of these latter features may have related to adaptation towards aquatic vision in mosasaurs, but further quantitative study of extant reptilian clades containing both terrestrial and aquatic taxa is critical and necessary in order to understand possible adaptive significances of such osteological features.
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Jourdeuil KA, Hammer CL, Franz-Odendaal TA. A comparative analysis of chick culturing methods on skeletogenesis. Anat Rec (Hoboken) 2015; 298:810-9. [PMID: 25641825 DOI: 10.1002/ar.23117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 11/23/2014] [Indexed: 01/19/2023]
Abstract
Chick embryos are desirable models for the study of developmental biology. Despite this, there are very few studies that examine the effect of different culturing methods on skeletogenesis, specifically, intramembranous and endochondral bones. This study presents a detailed description of these effects by comparing two different culturing methods: windowed (in the shell) eggs and ex-ovo or shell-less culturing to normal development. Using whole mount bone staining, we determined that there is no significant difference in the length of the ossified region of intramembranous and endochondral bones in control versus window cultured embryos. However, these bones are significantly underossified in shell-less embryos. Shell-less embryos also exhibit abnormalities in endochondral bones. Intramembranous bones, interestingly, are morphologically normal in shell-less embryos. This study provides the first detailed description of ossification in window (in-ovo) and shell-less (ex-ovo) cultured embryos compared with controls (in-ovo). Patterning of the skeleton is unaffected regardless of culturing method. We conclude that studies involving endochondral bones should not utilise shell-less culturing methods. This data has been lacking in the literature and will serve as an important resource for those using cultured chick embryos in the study of skeletogenesis.
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Affiliation(s)
- Karyn A Jourdeuil
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada; Department of Biology, Mount Saint Vincent University, Halifax, NS, Canada
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Chang CT, Franz-Odendaal TA. Perturbing the developing skull: using laser ablation to investigate the robustness of the infraorbital bones in zebrafish (Danio rerio). BMC DEVELOPMENTAL BIOLOGY 2014; 14:44. [PMID: 25516292 PMCID: PMC4282728 DOI: 10.1186/s12861-014-0044-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/10/2014] [Indexed: 01/13/2023]
Abstract
BACKGROUND The development of the craniofacial skeleton from embryonic mesenchyme is a complex process that is not yet completely understood, particularly for intramembranous bones. This study investigates the development of the neural crest derived infraorbital (IO) bones of the zebrafish (Danio rerio) skull. Located under the orbit, the IO bones ossify in a set sequence and are closely associated with the lateral line system. We conducted skeletogenic condensation and neuromast laser ablation experiments followed by shape analyses in order to investigate the relationship between a developing IO bone and the formation of the IO series as well as to investigate the highly debated inductive potential of neuromasts for IO ossification. RESULTS We demonstrate that when skeletogenic condensations recover from laser ablation, the resulting bone differs in shape compared to controls. Interestingly, neighbouring IO bones in the bone series are unaffected. In addition, we show that the amount of canal wall mineralization is significantly decreased following neuromast laser ablation at juvenile and larval stages. CONCLUSIONS These results highlight the developmental robustness of the IO bones and provide direct evidence that canal neuromasts play a role in canal wall development in the head. Furthermore, we provide evidence that the IO bones may be two distinct developmental modules. The mechanisms underlying developmental robustness are rarely investigated and are important to increase our understanding of evolutionary developmental biology of the vertebrate skull.
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Affiliation(s)
- Carolyn T Chang
- Department of Biology, Saint Mary's University, 923 Robie Street, Halifax, Nova Scotia, B3H 3C3, Canada.
| | - Tamara Anne Franz-Odendaal
- Department of Biology, Mount Saint Vincent University, 166 Bedford Highway, Halifax, Nova Scotia, B3M 2J6, Canada.
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Regulation of chondrocyte differentiation by IRE1α depends on its enzymatic activity. Cell Signal 2014; 26:1998-2007. [PMID: 24863879 DOI: 10.1016/j.cellsig.2014.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 05/15/2014] [Indexed: 12/27/2022]
Abstract
Bone morphogenetic protein 2(BMP2) is known to activate unfolded protein response (UPR) signal molecules in chondrogenesis. Inositol-requiring enzyme-1α (IRE1α),as one of three unfolded protein sensors in UPR signaling pathways, can be activated during ER stress. However, the influence on IRE1α in chondrocyte differentiation has not yet been elucidated. Here we present evidence demonstrating that overexpression of IRE1α inhibits chondrocyte differentiation, as revealed by reduced expression of collagen II (ColII), Sox9, collagen X (ColX), matrix metalloproteinase 13 (MMP-13), Indian hedgehog (IHH), Runx2 and enhanced expression of parathyroid hormone-related peptide (PTHrP). Furthermore, IRE1α-mediated inhibition of chondrogenesis depends on its enzymatic activity, since its point mutant lacking enzymatic activity completely loses this activity. The RNase and Kinase domains of IRE1α C-terminal are necessary for its full enzymatic activity and inhibition of chondrocyte differentiation. Mechanism studies demonstrate that granulin-epithelin precursor(GEP), a growth factor known to stimulate chondrogenesis, induced IRE1α expression in chondrogenesis. The expression of IRE1α is depended on GEP signaling, and IRE1α expression is hardly detectable in GEP(-/-) embryos. In addition, IRE1α inhibits GEP-mediated chondrocyte differentiation as a negative regulator. Altered expression of IRE1α in chondrocyte hypertrophy was accompanied by altered levels of IHH and PTHrP. Collectively, IRE1α may be a novel regulator of chondrocyte differentiation by 1) inhibition GEP-mediated chondrocyte differentiation as a negative regulator; 2) promoting IHH/PTHrP signaling.
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Guo FJ, Xiong Z, Han X, Liu C, Liu Y, Jiang R, Zhang P. XBP1S, a BMP2-inducible transcription factor, accelerates endochondral bone growth by activating GEP growth factor. J Cell Mol Med 2014; 18:1157-71. [PMID: 24636354 PMCID: PMC4508155 DOI: 10.1111/jcmm.12261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/24/2014] [Indexed: 01/22/2023] Open
Abstract
We previously reported that transcription factor XBP1S binds to RUNX2 and enhances chondrocyte hypertrophy through acting as a cofactor of RUNX2. Herein, we report that XBP1S is a key downstream molecule of BMP2 and is required for BMP2-mediated chondrocyte differentiation. XBP1S is up-regulated during chondrocyte differentiation and demonstrates the temporal and spatial expression pattern during skeletal development. XBP1S stimulates chondrocyte differentiation from mesenchymal stem cells in vitro and endochondral ossification ex vivo. In addition, XBP1S activates granulin-epithelin precursor (GEP), a growth factor known to stimulate chondrogenesis, and endogenous GEP is required, at least in part, for XBP1S-stimulated chondrocyte hypertrophy, mineralization and endochondral bone formation. Furthermore, XBP1S enhances GEP-stimulated chondrogenesis and endochondral bone formation. Collectively, these findings demonstrate that XBP1S, a BMP2-inducible transcription factor, positively regulates endochondral bone formation by activating GEP chondrogenic growth factor.
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Affiliation(s)
- Feng-Jin Guo
- Department of Cell Biology and Genetics, Core Facility of Development Biology, Chongqing Medical University, Chongqing, China
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McFadden SA, Tse DY, Bowrey HE, Leotta AJ, Lam CS, Wildsoet CF, To CH. Integration of defocus by dual power Fresnel lenses inhibits myopia in the mammalian eye. Invest Ophthalmol Vis Sci 2014; 55:908-17. [PMID: 24398103 DOI: 10.1167/iovs.13-11724] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Eye growth compensates in opposite directions to single vision (SV) negative and positive lenses. We evaluated the response of the guinea pig eye to Fresnel-type lenses incorporating two different powers. METHODS A total of 114 guinea pigs (10 groups with 9-14 in each) wore a lens over one eye and interocular differences in refractive error and ocular dimensions were measured in each of three experiments. First, the effects of three Fresnel designs with various diopter (D) combinations (-5D/0D; +5D/0D or -5D/+5D dual power) were compared to three SV lenses (-5D, +5D, or 0D). Second, the ratio of -5D and +5D power in a Fresnel lens was varied (50:50 compared with 60:40). Third, myopia was induced by 4 days of exposure to a SV -5D lens, which was then exchanged for a Fresnel lens (-5D/+5D) or one of two SV lenses (+5D or -5D) and ocular parameters tracked for a further 3 weeks. RESULTS Dual power lenses induced an intermediate response between that to the two constituent powers (lenses +5D, +5D/0D, 0D, -5D/+5D, -5D/0D and -5D induced +2.1 D, +0.7 D, +0.1 D, -0.3 D, -1.6 D and -5.1 D in mean intraocular differences in refractive error, respectively), and changing the ratio of powers induced responses equal to their weighted average. In already myopic animals, continued treatment with SV negative lenses increased their myopia (from -3.3 D to -4.2 D), while switching to SV positive lenses or -5D/+5D Fresnel lenses reduced their myopia (by 2.9 D and 2.3 D, respectively). CONCLUSIONS The mammalian eye integrates competing defocus to guide its refractive development and eye growth. Fresnel lenses, incorporating positive or plano power with negative power, can slow ocular growth, suggesting that such designs may control myopia progression in humans.
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Affiliation(s)
- Sally A McFadden
- School of Psychology, The University of Newcastle, New South Wales, Australia
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Jabalee J, Hillier S, Franz-Odendaal TA. An investigation of cellular dynamics during the development of intramembranous bones: the scleral ossicles. J Anat 2013; 223:311-20. [PMID: 23930967 PMCID: PMC3791124 DOI: 10.1111/joa.12095] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2013] [Indexed: 12/31/2022] Open
Abstract
The development of intramembranous bone is a dynamic and complex process requiring highly coordinated cellular activities. Although the literature describes the detailed cellular dynamics of early mesoderm-derived endochondral bone, studies regarding neural crest-derived intramembranous bone have failed to keep pace. We analyzed the development of chick scleral ossicles from the onset of osteoid deposition to mineralization at morphological, histological, and ultrastructural levels. We find that the mesenchymal condensations from which ossicles develop change their shape from ellipsoidal to trapezoidal concurrent with an increase in size. Furthermore, the size of an ossicle is dependent upon its time of induction. Our histological analyses of condensation growth reveal cell migration and osteoid secretion as key cellular processes determining condensation size; these processes occur concomitantly to increase both the area and thickness of condensations. We also describe the formation of the zone of overlap between ossicles and conclude that the process is similar to that of cranial suture formation. Finally, transmission electron microscopy of early condensations demonstrates that early osteoblasts secrete collagen parallel to the long axis of the condensation. This study elucidates fundamental mechanisms of intramembranous bone development at the cellular level, furthering our knowledge of this important process among vertebrates.
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Affiliation(s)
- J Jabalee
- Department of Biology, Mount Saint Vincent University, Halifax, NS, Canada
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Expression of CXCL12 and CXCL14 during eye development in chick and mouse. Gene Expr Patterns 2013; 13:303-10. [PMID: 23727298 DOI: 10.1016/j.gep.2013.05.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 05/13/2013] [Indexed: 02/05/2023]
Abstract
Vertebrate eye development is a complex multistep process coordinated by signals from the lens, optic cup and periocular mesenchyme. Although chemokines are increasingly being recognized as key players in cell migration, proliferation, and differentiation during embryonic development, their potential role during eye development has not been examined. In this study, we demonstrate by section in situ hybridization that CXCL12 and CXCL14 are expressed during ocular development. CXCL12 is expressed in the periocular mesenchyme, ocular blood vessels, retina, and eyelid mesenchyme, and its expression pattern is conserved between chick and mouse in most tissues. Expression of CXCL14 is localized in the ocular ectoderm, limbal epithelium, scleral papillae, eyelid mesenchyme, corneal keratocytes, hair follicles, and retina, and it was only conserved in the upper eyelid ectoderm of chick and mouse. The unique and non-overlapping patterns of CXCL12 and CXCL14 expression in ocular tissues suggest that these two chemokines may interact and have important functions in cell proliferation, differentiation and migration during eye development.
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Duench K, Franz-Odendaal TA. BMP and Hedgehog signaling during the development of scleral ossicles. Dev Biol 2012; 365:251-8. [DOI: 10.1016/j.ydbio.2012.02.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 12/20/2022]
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Abstract
PURPOSE To describe the clinical features and histopathology of epibulbar osseous choristoma in a series of patients. METHODS Noncomparative case series with chart review of 8 patients. RESULTS At presentation, the mean age of the patients was 19 years (median, 19 years; range, 0.8-38 years), with 6 women and 2 men (6 Caucasian, 1 Hispanic, and 1 African American). There were no related systemic syndromes, and visual acuity was unaffected in all cases. The choristoma was superotemporal (n = 8, 100%), with epicenter located in the fornix (n = 8, 100%), deep to Tenon fascia (n = 8, 100%), and of yellow (n = 2, 25%), white (n = 2, 25%), or pink (n = 4, 50%) color. The mean basal dimension was 9 mm (median, 10 mm; range, 3.5-14 mm), and mean thickness was 4 mm (median, 4 mm; range, 2-5 mm). Four cases were managed with observation and 4 with surgical excision, revealing tumor base adherent to the episclera (n = 2, 50%) or loose within Tenon fascia (n = 2, 50%). There were no cases to demonstrate intrascleral involvement, growth, or recurrence. CONCLUSIONS Epibulbar osseous choristoma is a congenital lesion of mature bone located superotemporally in the fornix at the level of Tenon fascia or episclera in young patients.
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Palumbo C, Cavani F, Sena P, Benincasa M, Ferretti M. Osteocyte apoptosis and absence of bone remodeling in human auditory ossicles and scleral ossicles of lower vertebrates: a mere coincidence or linked processes? Calcif Tissue Int 2012; 90:211-8. [PMID: 22290503 DOI: 10.1007/s00223-012-9569-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 01/05/2012] [Indexed: 10/14/2022]
Abstract
Considering the pivotal role as bone mechanosensors ascribed to osteocytes in bone adaptation to mechanical strains, the present study analyzed whether a correlation exists between osteocyte apoptosis and bone remodeling in peculiar bones, such as human auditory ossicles and scleral ossicles of lower vertebrates, which have been shown to undergo substantial osteocyte death and trivial or no bone turnover after cessation of growth. The investigation was performed with a morphological approach under LM (by means of an in situ end-labeling technique) and TEM. The results show that a large amount of osteocyte apoptosis takes place in both auditory and scleral ossicles after they reach their final size. Additionally, no morphological signs of bone remodeling were observed. These facts suggest that (1) bone remodeling is not necessarily triggered by osteocyte death, at least in these ossicles, and (2) bone remodeling does not need to mechanically adapt auditory and scleral ossicles since they appear to be continuously submitted to stereotyped stresses and strains; on the contrary, during the resorption phase, bone remodeling might severely impair the mechanical resistance of extremely small bony segments. Thus, osteocyte apoptosis could represent a programmed process devoted to make stable, when needed, bone structure and mechanical resistance.
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Affiliation(s)
- Carla Palumbo
- Dipartimento di Scienze Biomediche, Sezione di Morfologia umana-Istituti Anatomici, Università di Modena e Reggio Emilia, Via del Pozzo 71 (area Policlinico), 41125 Modena, Italy.
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Hall MI, Kirk EC, Kamilar JM, Carrano MT. Comment on "Nocturnality in dinosaurs inferred from scleral ring and orbit morphology". Science 2012. [PMID: 22194558 DOI: 10.1126/science.1208442] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Schmitz and Motani (Reports, 6 May 2011, p. 705) claimed to definitively reconstruct activity patterns of Mesozoic archosaurs using the anatomy of the orbit and scleral ring. However, we find serious flaws in the data, methods, and interpretations of this study. Accordingly, it is not yet possible to reconstruct the activity patterns of most fossil archosaurs with a high degree of confidence.
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Affiliation(s)
- Margaret I Hall
- Department of Physiology, Midwestern University, 19555 North 59th Avenue, Glendale, AZ 85308, USA
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40
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Zeiss CJ, Schwab IR, Murphy CJ, Dubielzig RW. Comparative retinal morphology of the platypus. J Morphol 2011; 272:949-57. [DOI: 10.1002/jmor.10959] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 12/30/2010] [Accepted: 02/26/2011] [Indexed: 01/03/2023]
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Franz-Odendaal TA. The ocular skeleton through the eye of evo-devo. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2011; 316:393-401. [DOI: 10.1002/jez.b.21415] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 02/22/2011] [Accepted: 03/24/2011] [Indexed: 11/06/2022]
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Thompson H, Griffiths JS, Jeffery G, McGonnell IM. The retinal pigment epithelium of the eye regulates the development of scleral cartilage. Dev Biol 2010; 347:40-52. [PMID: 20707994 PMCID: PMC2977850 DOI: 10.1016/j.ydbio.2010.08.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 07/28/2010] [Accepted: 08/03/2010] [Indexed: 01/01/2023]
Abstract
The majority of vertebrate species have a layer of hyaline cartilage within the fibrous sclera giving an extra degree of support to the eyeball. In chicks, this is seen as a cuplike structure throughout the scleral layer. However, the mechanisms that control the development of scleral cartilage are largely unknown. Here we have studied the phases of scleral cartilage development and characterised expression profiles of genes activated during the cartilage differentiation programme. CART1 and SOX9, the earliest markers of pre-committed cartilage, are expressed in the mesenchyme surrounding the optic cup. Later AGGRECAN, a matrix protein expressed during chondrocyte differentiation, is also expressed. The expression of these genes is lost following early removal of the optic cup, suggesting a role for this tissue in inducing scleral cartilage. By grafting young retinal pigment epithelium (RPE) and retina into cranial mesenchyme in vivo, it was found that RPE alone has the ability to induce cartilage formation. There are some exceptions within the vertebrates where scleral cartilage is not present; one such example is the placental mammals. However, we found that the cartilage differentiation pathway is initiated in mice as seen by the expression of Cart1 and Sox9, but expression of the later cartilage marker Aggrecan is weak. Furthermore, cartilage forms in mouse peri-ocular mesenchyme micromass culture. This suggests that the process halts in vivo before full differentiation into cartilage, but that murine scleral mesenchyme has retained the potential to make cartilage in vitro. RA, Wnts and Bmps have been linked to the cartilage development process and are expressed within the developing RPE. We find that RA may have a role in early scleral cartilage development but is not likely to be the main factor involved. These data reveal the course of scleral cartilage formation and highlight the key role that the optic cup plays in this process. The driving element within the optic cup is almost certainly the retinal pigmented epithelium.
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Affiliation(s)
- H Thompson
- Department of Veterinary Basic Science, Royal Veterinary College, London, NW1 0TU, UK
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Feng JQ, Guo FJ, Jiang BC, Zhang Y, Frenkel S, Wang DW, Tang W, Xie Y, Liu CJ. Granulin epithelin precursor: a bone morphogenic protein 2-inducible growth factor that activates Erk1/2 signaling and JunB transcription factor in chondrogenesis. FASEB J 2010; 24:1879-92. [PMID: 20124436 DOI: 10.1096/fj.09-144659] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Granulin epithelin precursor (GEP) has been implicated in development, tissue regeneration, tumorigenesis, and inflammation. Herein we report that GEP stimulates chondrocyte differentiation from mesenchymal stem cells in vitro and endochondral ossification ex vivo, and GEP-knockdown mice display skeleton defects. Similar to bone morphogenic protein (BMP) 2, application of the recombinant GEP accelerates rabbit cartilage repair in vivo. GEP is a key downstream molecule of BMP2, and it is required for BMP2-mediated chondrocyte differentiation. We also show that GEP activates chondrocyte differentiation through Erk1/2 signaling and that JunB transcription factor is one of key downstream molecules of GEP in chondrocyte differentiation. Collectively, these findings reveal a novel critical role of GEP growth factor in chondrocyte differentiation and the molecular events both in vivo and in vitro.
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Affiliation(s)
- Jian Q Feng
- Department of Biomedical Sciences, Baylor College of Dentistry, Texas A&M University System Health Science Center, Dallas, Texas, USA
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Hall MI. The relationship between the lizard eye and associated bony features: a cautionary note for interpreting fossil activity patterns. Anat Rec (Hoboken) 2009; 292:798-812. [PMID: 19462447 DOI: 10.1002/ar.20889] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Activity pattern, the time of day when an animal is active, is associated with ecology. There are two major activity patterns: diurnal (awake during the day in a photopic environment) and nocturnal (awake at night in a scotopic environment). Lizards exhibit characteristic eye shapes associated with activity pattern, with scotopic-adapted lizard eyes optimized for visual sensitivity with large corneal diameters relative to their eye axial lengths, and photopic-adapted lizards optimized for visual acuity, with larger axial lengths of the eye relative to their corneal diameters. This study: (1) quantifies the relationship between the lizard eye and its associated bony anatomy (the orbit, sclerotic ring, and associated skull widths); (2) investigates how activity pattern is reflected in that bony anatomy; and (3) determines if it is possible to reliably interpret activity pattern for a lizard that does not have the soft tissue available for study, specifically, for a fossil. Knowledge of extinct lizards' activity patterns would be useful in making paleoecological interpretations. Here, 96 scotopic- and photopic-adapted lizard species are analyzed in a phylogenetic context. Although there is a close relationship between the lepidosaur eye and associated bony anatomy, based on these data activity pattern cannot be reliably interpreted for bony-only specimens, such as a fossil, possibly because of the limited ossification of the lepidosaur skull. Caution should be exercised when utilizing lizard bony anatomy to interpret light-level adaptation, either for a fossil lizard or as part of an extant phylogenetic bracket to interpret other extinct animals with sclerotic rings, such as dinosaurs.
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Affiliation(s)
- Margaret I Hall
- Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona 85308, USA.
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Chapman G, Tarboush R, Eagles D, Connaughton V. A light and transmission electron microscope study of the distribution and ultrastructural features of peripheral nerve processes in the extra-retinal layers of the zebrafish eye. Tissue Cell 2009; 41:286-98. [DOI: 10.1016/j.tice.2008.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 12/06/2008] [Accepted: 12/24/2008] [Indexed: 12/19/2022]
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ADAMTS-7, a direct target of PTHrP, adversely regulates endochondral bone growth by associating with and inactivating GEP growth factor. Mol Cell Biol 2009; 29:4201-19. [PMID: 19487464 DOI: 10.1128/mcb.00056-09] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
ADAMTS-7, a metalloproteinase that belongs to ADAMTS family, is important for the degradation of cartilage extracellular matrix proteins in arthritis. Herein we report that ADAMTS-7 is upregulated during chondrocyte differentiation and demonstrates the temporal and spatial expression pattern during skeletal development. ADAMTS-7 potently inhibits chondrocyte differentiation and endochondral bone formation, and this inhibition depends on its proteolytic activity. The cysteine-rich domain of ADAMTS-7 is required for its interaction with the extracellular matrix, and the C-terminal four-thrombospondin motifs are necessary for its full proteolytic activity and inhibition of chondrocyte differentiation. ADAMTS-7 is an important target of canonical PTHrP signaling, since (i) PTHrP induces ADAMTS-7, (ii) ADAMTS-7 is downregulated in PTHrP null mutant (PTHrP-/-) growth plate chondrocytes, and (iii) blockage of ADAMTS-7 almost abolishes PTHrP-mediated inhibition of chondrocyte hypertrophy and endochondral bone growth. ADAMTS-7 associates with granulin-epithelin precursor (GEP), an autocrine growth factor that has been implicated in tissue regeneration, tumorigenesis, and inflammation. In addition, ADAMTS-7 acts as a new GEP convertase and neutralizes GEP-stimulated endochondral bone formation. Collectively, these findings demonstrate that ADAMTS-7, a direct target of PTHrP signaling, negatively regulates endochondral bone formation by associating with and inactivating GEP chondrogenic growth factor.
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Lin EA, Kong L, Bai XH, Luan Y, Liu CJ. miR-199a, a bone morphogenic protein 2-responsive MicroRNA, regulates chondrogenesis via direct targeting to Smad1. J Biol Chem 2009; 284:11326-35. [PMID: 19251704 DOI: 10.1074/jbc.m807709200] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
MicroRNAs (miRNA) are short non-coding RNA molecules that regulate a variety of biological processes. The role of miRNAs in BMP2-mediated biological processes is of considerable interest. A comparative miRNA array led to the isolation of several BMP2-responsive miRNAs. Among them, miR-199a(*) is of particular interest, because it was reported to be specifically expressed in the skeletal system. Here we demonstrate that miR-199a(*) is an early responsive target of BMP2: its level was dramatically reduced at 5 h, quickly increased at 24 h and remained higher thereafter in the course of BMP2-triggered chondrogenesis of a micromass culture of pluripotent C3H10T1/2 stem cells. miR-199a(*) significantly inhibited early chondrogenesis, as revealed by the reduced expression of early marker genes for chondrogenesis such as cartilage oligomeric matrix protein (COMP), type II collagen, and Sox9, whereas anti-miR-199a(*) increased the expression of these chondrogenic marker genes. A computer-based prediction algorithm led to the identification of Smad1, a well established downstream molecule of BMP-2 signaling, as a putative target of miR-199a(*). The pattern of Smad1 mRNA expression exhibited the mirror opposite of miR-199a(*) expression following BMP-2 induction. Furthermore, miR-199a(*) demonstrated remarkable inhibition of both endogenous Smad1 as well as a reporter construct bearing the 3-untranslated region of Smad1 mRNA. In addition, mutation of miR-199a(*) binding sites in the 3'-untranslated region of Smad1 mRNA abolished miR-199a(*)-mediated repression of reporter gene activity. Mechanism studies revealed that miR-199a(*) inhibits Smad1/Smad4-mediated transactivation of target genes, and that overexpression of Smad1 completely corrects miR-199a(*)-mediated repression of early chondrogenesis. Taken together, miR-199a(*) is the first BMP2 responsive microRNA found to adversely regulate early chondrocyte differentiation via direct targeting of the Smad1 transcription factor.
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Affiliation(s)
- Edward A Lin
- Department of Orthopaedic Surgery, New York University School of Medicine, New York, New York 10003, USA
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Ehrlich H, Koutsoukos PG, Demadis KD, Pokrovsky OS. Principles of demineralization: Modern strategies for the isolation of organic frameworks. Micron 2008; 39:1062-91. [DOI: 10.1016/j.micron.2008.02.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/08/2008] [Accepted: 02/10/2008] [Indexed: 11/16/2022]
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Franz-Odendaal TA, Hall BK. Skeletal elements within teleost eyes and a discussion of their homology. J Morphol 2006; 267:1326-37. [PMID: 17051547 DOI: 10.1002/jmor.10479] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Scleral ossicles and scleral cartilages form part of the craniofacial skeleton of many vertebrates. Some vertebrates, including all birds and most reptiles, but excluding most mammals, have scleral cartilages as well as scleral ossicles supporting their eyes. The teleost equivalent of these elements has received little attention in the literature. From radiographic and whole-mount analyses of over 400 individuals from 376 teleost species, we conclude that the teleost scleral skeletal elements (ossicles and cartilage) differ significantly from those of reptiles (including birds). Scleral ossicles in teleosts have different developmental origins, different positions within the eyeball, and different relationships with the scleral cartilaginous element than those in reptiles. From whole-mount staining of a growth series of four species of teleost (Danio rerio, Salmo salar, Esox lucius, and Alosa pseudoharengus), we interpret the development of these elements and show that they arise from within an Alcian blue-staining cartilaginous ring that develops around the eye earlier in development. We present possible scenarios on the evolution of these scleral skeletal elements from a common gnathostome ancestor, and consider that teleost scleral skeletal elements may not be homologous to those in reptiles. Our study indicates that homology cannot be assumed for these elements, despite the fact that they share the same name, scleral ossicles.
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