Down-regulation of CD53 expression in Epinephelus coioides under LPS, poly (I:C), and cytokine stimulation

Area of Science:

• Immunology
• Marine Biology
• Molecular Biology

Background:

• Tetraspanins are cell surface proteins crucial for various cellular functions, including immune cell activation.
• While well-studied in mammals, tetraspanin roles in teleosts (bony fishes) remain largely unexplored.
• CD53 is a key member of the tetraspanin superfamily with diverse biological functions.

Purpose of the Study:

• To characterize the CD53 gene and protein in orange-spotted grouper (Epinephelus coioices).
• To investigate the expression patterns of grouper CD53 in different tissues and cell types.
• To determine the effect of immune stimulation on CD53 expression in grouper.

Main Methods:

• Obtained and analyzed the open reading frame of grouper CD53 cDNA.
• Utilized quantitative real-time PCR (qPCR) to assess mRNA abundance.
• Employed immunochemistry and immunofluorescence to detect protein expression.
• Administered various immune stimulators (LPS, Poly (I:C), Vibrio, IL-6, CCL4) to fish.

Main Results:

• Grouper CD53 shares structural similarity with human CD53 despite low amino acid identity (38%).
• CD53 mRNA is highly expressed in immune organs like kidneys, spleen, thymus, gills, and blood.
• CD53 protein is primarily localized in leukocytes across various tissues.
• Expression of CD53 (mRNA and protein) was significantly downregulated following treatment with immune stimulators.

Conclusions:

• Grouper CD53 is a conserved molecule with significant expression in immune tissues and leukocytes.
• CD53 expression is modulated by immune challenges, indicating its potential role in fish immune responses.
• The findings suggest CD53 is involved in pathogen invasion and inflammatory reactions in teleosts.