Comparative analysis of transcriptional changes in zebrafish

Area of Science:

• * Ophthalmology and Regenerative Medicine
• * Molecular Biology and Genetics
• * Zebrafish as a model organism for retinal research

Background:

• * Adult zebrafish possess a remarkable capacity for retinal regeneration following injury, involving Müller glial cell activation.
• * Mutations in cep290 or bbs2 lead to progressive photoreceptor degeneration and inflammation, but lack a regenerative response.
• * Understanding the molecular basis for the failure of regeneration in these mutants is crucial for developing therapeutic strategies.

Purpose of the Study:

• * To identify transcriptional differences in zebrafish retinas with cep290 or bbs2 mutations during progressive photoreceptor degeneration.
• * To pinpoint shared biological processes and signaling pathways dysregulated in these models of inherited retinal degeneration.
• * To uncover molecular mechanisms that may inhibit Müller glial cell reprogramming and subsequent retinal regeneration.

Main Methods:

• * RNA-sequencing (RNA-seq) transcriptional profiling of cep290-/- and bbs2-/- zebrafish retinas compared to wild-type siblings.
• * Utilized the PANTHER Classification System for analyzing differentially expressed genes (DEGs) and associated biological pathways.
• * Focused on identifying shared DEGs and overrepresented pathways between the two mutant models.

Main Results:

• * Phototransduction genes were downregulated in both cep290 and bbs2 mutants.
• * Genes involved in the negative regulation of proliferation were upregulated, potentially inhibiting Müller glial cell proliferation.
• * A total of 815 DEGs were common to both mutants, enriched in pathways for inflammation, apoptosis, stress response, and PDGF signaling.

Conclusions:

• * Shared transcriptional pathways in cep290 and bbs2 mutants reveal molecular barriers to retinal regeneration.
• * Identifying these pathways provides targets for future interventions aimed at promoting photoreceptor regeneration.
• * This study lays the groundwork for understanding cell death regulation and Müller cell reprogramming inhibition in inherited retinal degeneration.