An integrated framework identified potent inhibitors targeting IRE1α.

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Inositol-requiring enzyme 1 alpha (IRE1α) is a key sensor in the unfolded protein response (UPR), crucial for endoplasmic reticulum (ER) homeostasis.
• IRE1α signaling dysregulation is linked to various diseases, highlighting the need for therapeutic targets.

Purpose of the Study:

• To identify and characterize flavonoids that modulate IRE1α activity.
• To investigate the potential of amentoflavone and glycitein as inhibitors of IRE1α kinase activity and activators of its RNase function.

Main Methods:

• Computational docking (AutoDock Vina, AutoDock Wizard, iGEMDOCK) to predict flavonoid binding affinities to IRE1α.
• In vitro kinase assays to determine IC50 values for amentoflavone and glycitein.
• Cell-based assays to assess anti-inflammatory effects and modulation of IRE1α-XBP1 signaling.

Main Results:

• Amentoflavone and glycitein demonstrated significant inhibition of IRE1α kinase activity (IC50: 16.4 μM and 23.68 μM, respectively).
• These flavonoids promote XBP1 splicing and IRE1α expression under normal conditions.
• Flavonoid pretreatment attenuated LPS-induced IRE1α-XBP1 signaling and reduced inflammation.

Conclusions:

• Amentoflavone and glycitein show promising modulatory effects on IRE1α, acting as both kinase inhibitors and RNase activators.
• This study is the first to report these dual modulatory properties for these flavonoids.
• Flavonoids represent a potential therapeutic strategy for ER stress and associated inflammatory conditions.