Umeå University's logo

umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Absence of Desmin in Myofibers of the Zebrafish Extraocular Muscles
Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).ORCID iD: 0000-0003-0885-6586
Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).ORCID iD: 0000-0003-3730-1790
Show others and affiliations
2020 (English)In: Translational Vision Science & Technology, E-ISSN 2164-2591, Vol. 9, no 10, article id 1Article in journal (Refereed) Published
Abstract [en]

Purpose: To study the medial rectus (MR) muscle of zebrafish (Danio rerio) with respect to the pattern of distribution of desmin and its correlation to distinct types of myofibers and motor endplates.

Methods: The MRs of zebrafish were examined using confocal microscopy in whole-mount longitudinal specimens and in cross sections processed for immunohistochemistry with antibodies against desmin, myosin heavy chain isoforms, and innervation markers. Desmin patterns were correlated to major myofiber type and type of innervation. A total of 1382 myofibers in nine MR muscles were analyzed.

Results: Four distinct desmin immunolabeling patterns were found in the zebrafish MRs. Approximately a third of all slow myofibers lacked desmin, representing 8.5% of the total myofiber population. The adult zebrafish MR muscle displayed en grappe, en plaque, and multiterminal en plaque neuromuscular junctions (NMJs) with intricate patterns of desmin immunolabeling.

Conclusions: The MRs of zebrafish showed important similarities with the human extraocular muscles with regard to the pattern of desmin distribution and presence of the major types of NMJs and can be regarded as an adequate model to further study the role of desmin and the implications of heterogeneity in cytoskeletal protein composition.

Translational Relevance: The establishment of a zebrafish model to study the cytoskeleton in muscles that are particularly resistant to muscle disease opens new avenues to understand human myopathies and muscle dystrophies and may provide clues to new therapies.

Place, publisher, year, edition, pages
Association for Research in Vision and Ophthalmology , 2020. Vol. 9, no 10, article id 1
Keywords [en]
extraocular muscles, desmin, neuromuscular junction, myosin heavy chain, zebrafish, multiterminal en plaque endplates
National Category
Ophthalmology
Identifiers
URN: urn:nbn:se:umu:diva-177160DOI: 10.1167/tvst.9.10.1ISI: 000587388500001PubMedID: 32953241Scopus ID: 2-s2.0-85093896190OAI: oai:DiVA.org:umu-177160DiVA, id: diva2:1507782
Available from: 2020-12-08 Created: 2020-12-08 Last updated: 2023-12-18Bibliographically approved
In thesis
1. Genetic studies of zebrafish muscles: clues to protection in muscle disease
Open this publication in new window or tab >>Genetic studies of zebrafish muscles: clues to protection in muscle disease
2023 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Genetiska studier av zebrafiskarnas muskler : ledtrådar om skydd mot muskeldystrofier
Abstract [en]

Muscular dystrophies (MDs) are caused by dysregulation of over 40 proteins but commonly share features of muscle weakness, myofiber death and regeneration, loss of ambulation and premature death. A MD involves a broken link anywhere in the connection from extracellular matrix through the sarcolemma to the sarcomere. Thus, any protein which is a part of this link causes MD if misfolded, dysregulated or absent. In MD, the most common causes of death are cardiac or respiratory failure, when the muscles involved in these processes fail. Although MDs affect 1:3500-5000 births worldwide there are currently no cures available. Extraocular muscles (EOMs) are strikingly not affected by MDs, however, the mechanisms behind this native resistance remain elusive. We have recently shown that the EOMs cytoskeleton differs significantly from that of other muscles and hypothesized that investigation of their cytoskeleton in MD models would provide important clues. Furthermore, we hypothesized that application of the EOMs strategies to trunk muscle tissue would decrease the detrimental impact of MD overall.

The zebrafish model system has recently increased vastly in popularity, and has quickly become a MD model. Due to its compatibility with the CRISPR/Cas9 method, genetic knockout studies can be utilized to generate novel mutant lines tailored to fit various aspects in studies of the zebrafish skeletal muscle. In this thesis I present nine new zebrafish lines which I used to study muscle biology processes, including muscle regeneration and the EOM cytoskeleton. 

Our results clearly demonstrate the need for understanding compensatory mechanisms in biology. Interestingly, pax3 and pax7 were shown to functionally compensate for each other both in appendicular muscle formation and in muscle regeneration, respectively, two processes where these individual genes have great impact in other organisms. This finding would also prove to be important in aiding our understanding of the EOM biology in adaptive strategies towards MDs. Furthermore, our results show that zebrafish EOMs are a good model to study cytoskeletal composition, as they share important features with human EOMs. Utilizing the CRISPR/Cas9 genome editing technique, I developed several knockout models of cytoskeletal proteins (desmin, obscurin, plectin) and studied their importance for the function of the EOMs.  In studies of zebrafish EOMs lacking obscurin, we found that EOMs functionally adapt their myosin composition over time via upregulation of myh7, a cardiac specific myosin. Furthermore, an RNA-sequencing screen on a CRISPR/Cas9 induced desminopathy model (desma; desmb double mutant) identified several protective genes of interest. We show that a four and a half LIM-domain protein (Fhl2) is upregulated in EOMs in several muscular dystrophy models and that fhl2b protects EOMs from excessive myonuclei turnover and hypertrophy. Furthermore, its ectopic expression in trunk muscle can also protect an additional muscle dystrophy model (dmd) from acute early death, improve myofiber function and stabilize neuromuscular junctions. Importantly, this protein was also detected in both human and mouse EOMs, indicating a potentially conserved role in the EOMs across species.

In summary, we identified several novel strategies of adaptation to disease progression in the EOMs. Together, these findings have contributed significantly to a better understanding of the EOMs and suggest new treatment strategies for MD that may have important future clinical applications.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2023. p. 75
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 2275
Keywords
zebrafish, muscle, extraocular muscles, intermediate filaments, bioinformatics, genetics, CRISPR/Cas9
National Category
Ophthalmology Cell and Molecular Biology
Research subject
ophthalmology; cell research
Identifiers
urn:nbn:se:umu:diva-218166 (URN)9789180702362 (ISBN)9789180702379 (ISBN)
Public defence
2024-01-26, Aula Biologica - BIO.E.203, Biologihuset, Umeå, 13:00 (English)
Opponent
Supervisors
Available from: 2023-12-21 Created: 2023-12-18 Last updated: 2023-12-19Bibliographically approved

Open Access in DiVA

fulltext(5456 kB)201 downloads
File information
File name FULLTEXT01.pdfFile size 5456 kBChecksum SHA-512
dcacbfb09a820d3a705a4db052fd2e01e83444abe947313772d21675188f66df251a4b5f1490b206da59a4eadb465fcf39860175be7eeef2617dbfc5ec00a23b
Type fulltextMimetype application/pdf

Other links

Publisher's full textPubMedScopus

Authority records

Dennhag, NilsLiu, Jing-XiaNord, Hannavon Hofsten, JonasDomellöf, Fatima Pedrosa

Search in DiVA

By author/editor
Dennhag, NilsLiu, Jing-XiaNord, Hannavon Hofsten, JonasDomellöf, Fatima Pedrosa
By organisation
Department of Integrative Medical Biology (IMB)Ophthalmology
In the same journal
Translational Vision Science & Technology
Ophthalmology

Search outside of DiVA

GoogleGoogle Scholar
Total: 201 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 371 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf