Small molecule splicing modulators that disrupt O-GlcNAc homeostasis

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• O-Linked N-acetylglucosamine (O-GlcNAc) is a crucial post-translational modification regulated by OGT and OGA.
• Dysregulation of O-GlcNAc is implicated in various human diseases, driving therapeutic interest.
• Drug repurposing offers a strategy to identify compounds that modulate O-GlcNAc pathways.

Purpose of the Study:

• To identify clinically relevant compounds that can therapeutically modulate O-GlcNAc homeostasis.
• To investigate the intersection of drug repurposing candidates with O-GlcNAc cycling enzymes.
• To uncover novel mechanisms for disrupting O-GlcNAc homeostasis.

Main Methods:

• Conducted three parallel drug repurposing screens in cells and in vitro targeting O-GlcNAc cycling enzymes.
• Utilized kinase inhibitors GSK690693 and Y-33075 to assess their impact on O-GlcNAc homeostasis.
• Evaluated a panel of splicing modulators for their effects on OGT and OGA expression.

Main Results:

• GSK690693 and Y-33075 were identified as splicing modulators that disrupt O-GlcNAc homeostasis by downregulating OGT and OGA.
• These effects were independent of the inhibitors' known targets (AKT and ROCK) and distinct from direct OGT/OGA inhibitors.
• Additional splicing modulators (OTS964, indisulam, GNF2133) were found to downregulate OGT and OGA with unique splicing profiles.

Conclusions:

• Kinase inhibitors can act as splicing modulators to disrupt O-GlcNAc homeostasis.
• Drug repurposing screens revealed novel chemotypes targeting O-GlcNAc cycling enzymes through splicing modulation.
• These findings provide new therapeutic strategies for diseases associated with O-GlcNAc dysregulation.