The sonic hedgehog signaling pathway is suppressed following PCB₁₂₅₄ exposure during retinal development

Area of Science:

• Environmental toxicology
• Developmental biology
• Neuroscience

Background:

• Polychlorinated biphenyls (PCBs) are environmental pollutants known to cause adverse health effects.
• Retinal development is a complex process susceptible to environmental insults.
• The Sonic hedgehog (Shh) signaling pathway plays a crucial role in embryonic development, including the eye.

Purpose of the Study:

• To investigate the role of the Shh signaling pathway in retinal development following exposure to Polychlorinated biphenyl 1254 (PCB₁₂₅₄).
• To examine the effects of PCB₁₂₅₄ exposure on cell proliferation, apoptosis, and Shh pathway gene/protein expression in retinal models.

Main Methods:

• Utilized zebrafish and RGC-5 retinal cell lines for in vivo and in vitro experiments.
• Assessed cell proliferation and apoptosis levels.
• Quantified mRNA and protein expression of Shh, ptch2, gli1, and gli2 using RT-qPCR, immunofluorescence, and western blotting.

Main Results:

• PCB₁₂₅₄ exposure significantly inhibited proliferation and increased apoptosis in retinal cells.
• Shh mRNA and protein expression were decreased in PCB₁₂₅₄-treated groups.
• Expressions of ptch2 mRNA and protein were upregulated, while gli1 and gli2 mRNA/protein levels were downregulated following PCB₁₂₅₄ exposure.

Conclusions:

• The Shh signaling pathway is implicated in the retinal developmental damage caused by PCB₁₂₅₄ exposure.
• Environmental pollutants like PCBs can contribute to the etiology of eye diseases.
• Findings highlight the vulnerability of developing retinas to toxic environmental agents.