4μ8C (IRE1 Inhibitor III) is a small-molecule inhibitor of IRE1α[1]. Additionally impedes Xbp1 mRNA splicing in a dose-responsive manner when added to the culture media of ER-stressed cells. This inhibitor's binding to IRE1 is characterized by a slow dissociation rate, although removal of the inhibitor allows for a quick resumption of Xbp1 splicing in the cells[1]. The mechanism by which 4μ8C operates, especially in preventing the splicing of XBP1 mRNA under ER stress conditions, such as those induced by mutant proinsulin production, provides insight into its potential application in managing ER stress-related cellular dysfunctions[2]. Treatment with 4μ8C significantly reduces IL-4 production by CD4+ T cells under Th0 conditions, as evidenced by decreased IL-4 levels in culture supernatants and a lower percentage of IL-4 positive cells. The production of IL-5 and IL-13 is also notably diminished following 4μ8C administration[3].
体内研究
Intraperitoneal injection of 4μ8c (IRE1 Inhibitor III), at a dosage of 10 mg/kg/day for an additional four weeks, results in a marked decrease (45.2%) in the atherosclerotic lesion area in en face aorta samples, demonstrating 4μ8c's capacity to effectively impede plaque formation in mice[4].
Oral administration of 4μ8C at doses of 10, 50, or 100 mg/kg efficiently curtails passive cutaneous anaphylaxis (PCA) in mice, with an effective dose 50 (ED50) of 25.1 mg/kg[5].
Additionally, 4μ8C counteracts the ER stress-induced depletion of several recognized RIDD targets, showcasing an EC50 roughly equivalent to that for the inhibition of XBP1 target gene activation, approximately 4 μM[1].
体外研究
4μ8C (IRE1 Inhibitor III) is a small-molecule inhibitor of IRE1α[1].
Additionally impedes Xbp1 mRNA splicing in a dose-responsive manner when added to the culture media of ER-stressed cells. This inhibitor's binding to IRE1 is characterized by a slow dissociation rate, although removal of the inhibitor allows for a quick resumption of Xbp1 splicing in the cells[1].
The mechanism by which 4μ8C operates, especially in preventing the splicing of XBP1 mRNA under ER stress conditions, such as those induced by mutant proinsulin production, provides insight into its potential application in managing ER stress-related cellular dysfunctions[2].
Treatment with 4μ8C significantly reduces IL-4 production by CD4+ T cells under Th0 conditions, as evidenced by decreased IL-4 levels in culture supernatants and a lower percentage of IL-4 positive cells. The production of IL-5 and IL-13 is also notably diminished following 4μ8C administration[3].
4μ8C 细胞实验
Cell Line
Concentration
Treated Time
Description
References
FL-DCs
50 µM
5 h
Inhibition of IRE1α endonuclease activity, reducing the production of IL-12p40
Front Immunol. 2019 Jan 4;9:3050.
FL-DCs
20 µM
2 h
Inhibition of IRE1α endonuclease activity, reducing the production of pro-inflammatory cytokines IL-6, TNF-α, and IL-10
Front Immunol. 2019 Jan 4;9:3050.
Primary rat β-cells
25 µM
24 h
4μ8C inhibited the IRE1-JNK signaling pathway, reducing DP5 expression and thereby decreasing palmitate-induced β-cell apoptosis.
Diabetes. 2012 Nov;61(11):2763-75.
INS-1E cells
25 µM
16 h
4μ8C effectively blocked IRE1, significantly reducing JNK phosphorylation and DP5 expression, thereby partially protecting β-cells from palmitate-induced apoptosis.
Diabetes. 2012 Nov;61(11):2763-75.
U2OS cells
30 μM
Inhibits IRE1 RNAse activity but does not affect TBEV infectivity
Nat Commun. 2019 Aug 29;10(1):3889.
Bone marrow-derived macrophages (BMDMs)
100 μM
1 h
To evaluate the effect of IRE1 RNase inhibitor 4μ8C on LCWE-induced NLRP3 inflammasome activation and IL-1β secretion. Results showed that 4μ8C treatment decreased IL-1β and Casp-1 secretion.
JCI Insight. 2022 Mar 22;7(6):e157203.
16HBE cells
30 μM
Inhibits IRE1-mediated XBP1 mRNA splicing
PLoS Pathog. 2015 Jun 17;11(6):e1004946.
K562 cells
32 μM
20 h
Inhibiting the IRE1 signaling pathway protected cells from palmitate-mediated lipotoxicity
Mol Cell. 2019 Apr 4;74(1):32-44.e8.
3T3-L1 adipocytes
30 or 60 μM
1 h
Inhibited IRE1 RNase activity but did not reduce lipolysis
J Biol Chem. 2021 Jan-Jun;296:100440.
4μ8C 动物实验
Species
Animal Model
Administration
Dosage
Frequency
Description
References
Mice
LCWE-induced Kawasaki disease vasculitis model
Intraperitoneal injection
10 mg/kg
Once daily, starting 2 days before LCWE injection until day 7 after LCWE injection
To evaluate the effect of IRE1 RNase inhibitor 4μ8C on LCWE-induced cardiovascular lesions. Results showed that 4μ8C treatment reduced heart inflammation and the development of abdominal aorta dilations, and decreased Casp-1 activity.
JCI Insight. 2022 Mar 22;7(6):e157203.
Mice
High-fat diet-induced metabolic abnormalities model
Intraperitoneal injection
10 mg/kg
Once daily for one week
Inhibit IRE1 activity and restore SIRT1 expression and metabolic functions
Inhibition of XBP-1s expression in human Jeko cells after 24 hrs by immunoblotting analysis, IC50=1.57 μM
24749861
human Mino cells
Function assay
24 h
Inhibition of XBP-1s expression in human Mino cells after 24 hrs by immunoblotting analysis, IC50=1.62 μM
24749861
SF21 cells
Function assay
30 mins
Inhibition of human recombinant puritin-His-tagged IRE-1 RNase expressed in SF21 cells using XBP-1 RNA stem loop as substrate incubated for 30 mins prior to substrate addition measured after 2 hrs by FRET-suppression assay, IC50=0.206 μM
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