Inositol-requiring enzyme 1 (IRE1) is the most highly conserved signaling node of the unfolded protein response (UPR) and represents a potential therapeutic target for a number of diseases associated with endoplasmic reticulum stress. IRE1 activates the XBP-1 transcription factor by site-specific cleavage of two hairpin loops within its mRNA to facilitate its nonconventional splicing and alternative translation. We screened for inhibitors using a construct containing the unique cytosolic kinase and endoribonuclease domains of human IRE1α (hIRE1α-cyto) and a mini-XBP-1 stem-loop RNA as the substrate. One class compounds was salicylaldehyde analogs from the hydrolyzed product of salicylaldimines in the library. Salicylaldehyde analogs were active in inhibiting the site-specific cleavage of several mini-XBP-1 stem-loop RNAs in a dose-dependent manner. Salicyaldehyde analogs were also active in inhibiting yeast Ire1 but had little activity inhibiting RNase L or the unrelated RNases A and T1. Kinetic analysis revealed that one potent salicylaldehyde analog, 3-ethoxy-5,6-dibromosalicylaldehyde, is a non-competitive inhibitor with respect to the XBP-1 RNA substrate. Surface plasmon resonance studies confirmed this compound bound to IRE1 in a specific, reversible and dose-dependent manner. Salicylaldehydes inhibited XBP-1 splicing induced pharmacologically in human cells. These compounds also blocked transcriptional up-regulation of known XBP-1 targets as well as mRNAs targeted for degradation by IRE1. Finally, the salicylaldehyde analog 3-methoxy-6-bromosalicylaldehyde strongly inhibited XBP-1 splicing in an in vivo model of acute endoplasmic reticulum stress. To our knowledge, salicylaldehyde analogs are the first reported specific IRE1 endoribonuclease inhibitors.

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I wish to discuss various topics that are of great importance to my company and the textile coatings industry in the United States I will briefly review hydrophobic and hydrophilic polyurethane coatings in this paper The textile indus try has seen significant changes in the last few years, and imports have eroded our in dustry to a great extent To turn the tide, we have concentrated on high tech textiles and niche markets to survive in the late 1990s and into the 21st century

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