Abstract
Purpose :
To examine the differential gene expression and test the possible interplay between Yap/Taz-mediated mechanotransduction and Tgfb-receptor-mediated signaling in keratocytes for corneal stromal development and maintenance in Tgfb receptor signaling-deficiency mouse models.
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Methods :
Alk5-cko, Tbr2-cko, and Smad4-cko mouse strains in which Alk5, Tbr2, and Smad4 genes were conditionally knocked out (cko) in the keratocan (Kera)-positive corneal stromal cells, respectively. Optuvue optical coherence tomography (OCT) system was harnessed to examine the corneal thickness. 10x visium spatial transcriptomics was performed to compare corneal mRNA expression profile comparison was compared between Tbr2-cko and Tbr2 wild-type.
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Results :
Corneal stroma thickness was reduced by 40%-45% in all cko mice as compared with those of the wild-type control littermates. The expression level of Yap/Taz and Cathepsin b was significantly increased in the knockout cornea. The top 30 differential gene expression heatmap and Reactome pathway database analysis based on 10x-genomics visium spatial corneal transcriptomic analysis showed that genes annotated to the ECM synthesis and organization pathways were significantly downregulated in Tbr2-cko as compared with those in Tbr2 wild-type littermate. Representative 10x-genomics visium spatial gene expression on three slides of frozen section showed that Col5a1 and Npnt (Nephronectin) are significantly downregulated in Tbr2-cko as compared with Tbr2 wild-type.
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Conclusions :
Our data suggested that loss-of-function of Alk5, Tbr2, or Smad4 may unravel the genetic-defined mechanism for corneal ectasia. The interplay between Tgf-b signaling and mechanotransduction in keratocytes plays a pivotal role in corneal stromal development and homeostasis. Interruption of these interactions results in profound corneal thinning and ectasia, leading to corneal ectasia formation. Alk5-cko, Tbr2-cko, and Smad4-cko mouse strains serve as potential animal models to elucidate the role of Tgf-b signaling in mediating mechanical stress in keratocytes for corneal biology and pathobiology.
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This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.