S1P, Generated by Sphingosine Kinase 1, Negatively Affects Corneal Wound Healing Process by Activating TGF-β/Smad...

Area of Science:

• Ophthalmology
• Cell Biology
• Biochemistry

Background:

• Corneal opacity, a leading cause of blindness, results from abnormal healing of corneal injuries.
• Complex signaling pathways govern corneal healing, and a lack of understanding hinders therapeutic development.
• Sphingosine-1-phosphate (S1P) and transforming growth factor beta (TGFβ) signaling are implicated in tissue fibrosis.

Purpose of the Study:

• To elucidate the interplay between S1P and TGFβ signaling in corneal wound healing and fibrosis.
• To determine the role of sphingosine kinase 1 (SphK1) in modulating these pathways.

Main Methods:

• Corneal alkali burn injury was induced in Sphingosine kinase 1 gene knockout (Sphk1^-/-) mice and wildtype littermates.
• Wound healing, TGFβ signaling intermediates, and profibrotic protein expression were assessed at various days postinjury.
• Exogenous SphK1 inhibition was tested in wildtype mice.

Main Results:

• Sphk1^-/- mice exhibited accelerated corneal epithelial closure compared to wildtype controls.
• Reduced activation of Smad2/3 and altered expression of Smad4 and Smad7 were observed in Sphk1^-/- mice.
• Pharmacological inhibition of SphK1 accelerated wound healing in wildtype mice.

Conclusions:

• S1P signaling positively influences TGFβ pathways, delaying corneal wound healing and promoting fibrosis.
• Inhibition of S1P signaling accelerates corneal wound healing and may prevent fibrosis and scar formation.
• Targeting S1P signaling presents a potential therapeutic strategy for corneal injury recovery.