Dataset Information

Ultrastructural and molecular analysis of the origin and differentiation of cells mediating brittle star skeletal regeneration.

ABSTRACT:

Background

Regeneration is the ability to re-grow body parts or tissues after trauma, and it is widespread across metazoans. Cells involved in regeneration can arise from a pool of undifferentiated proliferative cells or be recruited from pre-existing differentiated tissues. Both mechanisms have been described in different phyla; however, the cellular and molecular mechanisms employed by different animals to restore lost tissues as well as the source of cells involved in regeneration remain largely unknown. Echinoderms are a clade of deuterostome invertebrates that show striking larval and adult regenerative abilities in all extant classes. Here, we use the brittle star Amphiura filiformis to investigate the origin and differentiation of cells involved in skeletal regeneration using a combination of microscopy techniques and molecular markers.

Results

Our ultrastructural analyses at different regenerative stages identify a population of morphologically undifferentiated cells which appear in close contact with the proliferating epithelium of the regenerating aboral coelomic cavity. These cells express skeletogenic marker genes, such as the transcription factor alx1 and the differentiation genes c-lectin and msp130L, and display a gradient of morphological differentiation from the aboral coelomic cavity towards the epidermis. Cells closer to the epidermis, which are in contact with developing spicules, have the morphology of mature skeletal cells (sclerocytes), and express several skeletogenic transcription factors and differentiation genes. Moreover, as regeneration progresses, sclerocytes show a different combinatorial expression of genes in various skeletal elements.

Conclusions

We hypothesize that sclerocyte precursors originate from the epithelium of the proliferating aboral coelomic cavity. As these cells migrate towards the epidermis, they differentiate and start secreting spicules. Moreover, our study shows that molecular and cellular processes involved in skeletal regeneration resemble those used during skeletal development, hinting at a possible conservation of developmental programmes during adult regeneration. Finally, we highlight that many genes involved in echinoderm skeletogenesis also play a role in vertebrate skeleton formation, suggesting a possible common origin of the deuterostome endoskeleton pathway.

SUBMITTER: Piovani L

PROVIDER: S-EPMC7814545 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Publications

Ultrastructural and molecular analysis of the origin and differentiation of cells mediating brittle star skeletal regeneration.

Piovani Laura L Czarkwiani Anna A Ferrario Cinzia C Sugni Michela M Oliveri Paola P

BMC biology 20210118 1

<h4>Background</h4>Regeneration is the ability to re-grow body parts or tissues after trauma, and it is widespread across metazoans. Cells involved in regeneration can arise from a pool of undifferentiated proliferative cells or be recruited from pre-existing differentiated tissues. Both mechanisms have been described in different phyla; however, the cellular and molecular mechanisms employed by different animals to restore lost tissues as well as the source of cells involved in regeneration rem ...[more]

PMID: 33461552

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Project description:The brittle star Amphiura filiformis, which regenerates its arms post autotomy, is emerging as a useful model for studying the molecular underpinnings of regeneration, aided by the recent availability of some molecular resources. During regeneration a blastema initially is formed distally to the amputation site, and then a rapid rebuild is obtained by adding metameric units, which will eventually differentiate and become fully functional. In this work we first characterize the developmental process of the regenerating arms using two differentiation markers for muscle and skeletal structures - Afi-trop-1 and Afi-?coll. Both genes are not expressed in the blastema and newly added undifferentiated metameric units. Their expression at different regenerating stages shows an early segregation of muscle and skeletal cells during the regenerating process, long before the metameric units become functional. We then studied the expression of a set of genes orthologous of the sea urchin transcription factors involved in the development of skeletal and non-skeletal mesoderm: Afi-ets1/2, Afi-alx1, Afi-tbr, Afi-foxB and Afi-gataC. We found that Afi-ets1/2, Afi-alx1, Afi-foxB and Afi-gataC are all expressed at the blastemal stage. As regeneration progresses those genes are expressed in a similar small undifferentiated domain beneath the distal growth cap, while in more advanced metameric units they become restricted to different skeletal domains. Afi-foxB becomes expressed in non-skeletal structures. This suggests that they might play a combinatorial role only in the early cell specification process and that subsequently they function independently in the differentiation of different structures. Afi-tbr is not present in the adult arm tissue at any stage of regeneration. In situ hybridization results have been confirmed with a new strategy for quantitative PCR (QPCR), using a subdivision of the three stages of regeneration into proximal (differentiated) and distal (undifferentiated) arm segments.

Project description:This study set out to evaluate the wound healing properties of brittle star extracts in vitro and in vivo. Due to the great arm regeneration potential of the brittle star, Ophiocoma cynthiae, the present study aimed to evaluate the wound healing effect of hydroalcoholic extracts of brittle star undergoing arm regeneration in wound healing models. The brittle star samples were collected from Nayband Bay, Bushehr, Iran. After wound induction in the arm of brittle stars, hydroalcoholic extracts relating to different times of arm regeneration were prepared. The GC-MS analysis, in vitro MTT cell viability and cell migration, Western blot, and computational analysis tests were performed. Based on the in vitro findings, two BSEs were chosen for in vivo testing. Macroscopic, histopathological and biochemical evaluations were performed after treatments. The results showed positive proliferative effects of BSEs. Specifically, forty-two compounds were detected in all groups of BSEs using GC-MS analysis, and their biological activities were assessed. The MTT assay showed that the 14 d BSE had a higher proliferative effect on HFF cells than 7 d BSE. The cell migration assay showed that the wound area in 7 d and 14 d BSEs was significantly lower than in the control group. Western blot analysis demonstrated an increase in the expression of proliferation-related proteins. Upon the computational analysis, a strong affinity of some compounds with proteins was observed. The in vivo analysis showed that the evaluation of wound changes and the percentage of wound healing in cell migration assay in the 7 d BSE group was better than in the other groups. Histopathological scores of the 7 d BSE and 14 d BSE groups were significantly higher than in the other groups. In conclusion, the hydroalcoholic extract of O. cynthiae undergoing arm regeneration after 7 and 14 days promoted the wound healing process in the cell and rat skin wound healing model due to their proliferative and migratory biological activity.

Dataset Information

Ultrastructural and molecular analysis of the origin and differentiation of cells mediating brittle star skeletal regeneration.

Background

Results

Conclusions

Publications

Ultrastructural and molecular analysis of the origin and differentiation of cells mediating brittle star skeletal regeneration.

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