C-178

humand and mouse STING

C-178 includes a region of mmSTING's N-terminal that crosses the membrane domain but is not well understood. Moreover, C-178 impedes this process by blocking STING's palm phospholipidation. Human cells are not substantially impacted by C-178. The gene expression profile of BMDM is not significantly affected by C-178 alone (0-1 μM; 1 hour). Furthermore, it prevents TBK1[1] phosphorylation that is brought on by CMA. In macrophages generated from mouse bone marrow, C-178 (1 μM; 1 hour) decreases Ifnb1 expression triggered by cdG, dsDNA, CMA, and LPS [1]. In mouse embryonic fibroblasts, C-178 (1 μM; 0.5-4 hours) suppresses the production of p-TBK1 and sting protein produced by CMA in a time-dependent manner[1].

Because we noticed improved solubility of C-176 relative to C-178, we chose this compound for in vivo studies. First we verified that the compounds target STING by using an in vivo click-chemistry approach and also assessed the pharmacokinetic profile of C-176 on single-dose intraperitoneal injection. We next evaluated whether C-176 can suppress the induction of type I IFNs triggered by the administration of CMA. Of note, pretreatment with C-176 markedly reduced the CMA-mediated induction of serum levels of type I IFNs and IL-6. Thus, C-176 is effective in mice and—as expected for a covalent inhibitor—the short serum half-life does not limit its in vivo inhibitory capacity. To assess the potential of C-176 to antagonize STING in a model of autoinflammatory disease, we investigated its efficacy in Trex1−/− mice. Trex1−/− mice show signs of severe multi-organ inflammation caused by the persistent activation of the cyclic GMP–AMP synthase–STING pathway and recapitulate certain pathogenic features of Aicardi–Goutières syndrome in humans. Having verified that C-178 suppresses interferon-stimulated genes in cells from Trex1−/− mice, we performed a two-week in vivo efficacy study with C-176. Notably, treatment of Trex1−/− mice with C-176 resulted in a significant reduction in serum levels of type I IFNs and in a strong suppression of inflammatory parameters in the heart. Wild-type mice on a two-week treatment with C-176 showed no evident signs of overt toxicity. We next conducted a three-month trial with C-176 in Trex1−/− mice, which demonstrated marked amelioration of various signs of systemic inflammation. Thus, C-176 attenuates STING-associated autoinflammatory disease in mice [1].

Competition assay[1]
HEK293T cells expressing Flag–STING were incubated with the indicated compounds and after 1 h, C-176-AL was added for 1 h. Cells were collected in PBS and analysed by in-gel analysis of C-176-AL-mediated labelling of STING (see ‘ Gel-based analysis of compound binding to STING’).

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Gel-based analysis of compound binding to STING[1]
HEK293T cells expressing Flag–STING were incubated with C-176-AL, C-175-AZ, iodoacetamide azide (Thermo Fisher) or H-151-AL in serum-free medium, collected in PBS and lysed by repetitive freezing and thawing. Forty-three microlitres of lysed cells was treated with a freshly prepared ‘click reagent’ mixture containing tris(benzyltriazolylmethyl)amine (TBTA) (3 μl per sample, 3 mM in 1:4 DMSO:t-ButOH), tetramethylrhodamine (TAMRA) azide, SiR azide (Spirochrome) or SiR alkyne (Spirochrome) (2 μl per sample, 1.25 mM in DMSO), and freshly prepared CuSO4 (1 μl per sample) and tris-(2-carboxyethyl)phosphine hydrochloride (TCEP) (1 μl per sample) and incubated at room temperature for 30 min. The reaction was quenched by addition of reducing sample buffer. In-gel fluorescence was visualized using Fusion FX (Vilber Lourmat) and analysed by Fusion capt advance acquisition software.

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Crosslinking with disuccinimidyl suberate[1]
HEK293T cells expressing Flag–mmSTING were incubated with or without C-176 (1 μM) for 1 h and treated with DMSO or CMA (250 μg ml−1) for 2 h. Crosslinking was performed in PBS with 1 mM disuccinimidyl suberate (DSS) (Thermo Fisher) freshly prepared in DMSO at room temperature for 1 h.

Western Blot Analysis[1]
Cell Types: Mouse Bone Marrow-Derived Macrophages (BMDMs)
Tested Concentrations: 0 μM; p-TBK1 and Stinging Humidity Fibrogenesis Cellular protein expression occurs over time [1]. 0.125μM; 0.25μM; 0.5μM; 1 μM
Incubation Duration: 1 hour
Experimental Results: Inhibited CMA-induced p-TBK1 expression in a dose-dependent manner.

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RT-PCR[1]
Cell Types: Mouse bone marrow-derived macrophages (BMDM)
Tested Concentrations: 1 μM
Incubation Duration: 1 hour
Experimental Results: Ifnb1 expression was down-regulated in BMDM.

C57BL/6J mice (stock number 000664) were purchased from Jackson Laboratories. TREX1-deficient mice were a gift from T. Lindahl31 and were backcrossed for >10 generations to C57BL/6NJ. Mice were maintained under specific-pathogen-free (SPF) conditions at EPFL. For the pharmacokinetic studies, wild-type mice were injected intraperitoneally with 750 nmol C-176 per mouse in 200 μl corn oil (Sigma). Blood was collected at 30 min, 2 h and 4 h and serum C-176 levels were measured by mass spectrometry (liquid chromatography–high-resolution mass spectrometry). To assess the in vivo inhibitory effect of C-176, wild-type mice (8–12 weeks of age) were injected either with vehicle or C-176. After 1 h or 4 h, CMA was administered at a concentration of 224 mg kg−1. Four hours later, mice were euthanized and the serum was collected to measure CMA-induced cytokine levels. To assess the in vivo inhibitory effect of H-151, wild-type mice were injected intraperitoneally with 750 nmol H-151 per mouse in 200 μl 10% Tween-80 in PBS. After 1 h CMA (112 mg kg−1) was administered, and after 4 h mice were euthanized and the serum was collected. The efficacy study in Trex1−/− mice was conducted as follows: mice (2–5 weeks of age) were injected with 7.5 μl of C-176 or DMSO dissolved in 85 μl corn oil twice per day for 11 consecutive days. Mice were euthanized by anaesthetization in a CO2 chamber followed by cervical dislocation. For toxicology studies, 8-week-old mice were injected daily with 562.5 nmol of C-176 for 2 weeks. At day 14, blood samples were collected in lithium-heparin-coated tubes (Microvette CB 300 Hep-Lithium), and plasma was isolated after centrifugation at 4 °C and then stored at −80 °C. Plasma parameters were measured using DimensionXpand Plus (Siemens Healthcare Diagnostics AG). For the peripheral blood cell profile, 100 μl of blood was collected in EDTA-K-coated tubes (Microvette CB 300 EDTA K2). Complete blood counts were analysed with an ADVIA120 haematology system (Siemens Healthcare Diagnostics AG). For the detection of luciferase activity, Trex1−/−Ifnb1Δβ-luc/Δβ-luc reporter mice32 (aged 4–7 weeks) were injected intraperitoneally daily for 7 days with 750 nmol H-151 or DMSO in 200 μl PBS 0.1% Tween-80. For in vivo imaging, mice were anaesthetized with isofluran and injected intravenously with 15 mg kg−1 XenoLight D-luciferin (Perkin Elmer) in isotonic sodium chloride. Photon flux was quantified two minutes after injection on an In-vivo Xtreme II imaging device (Bruker) with binning set to 8 × 8 pixels and an integration time of 3 min. Animal experiments were approved either by the Service de la Consommation et des Affaires Vétérinaires of the canton of Vaud (Switzerland) or by the Landesdirektion Dresden (Germany) and were performed in accordance with the respective legal regulations [1].

[1]. Haag SM, et al. Targeting STING with covalent small-molecule inhibitors. Nature. 2018 Jul;559(7713):269-273.

C17H10N2O5

322.28

322.059

C, 62.49; H, 5.59; N, 9.72; O, 22.20

329198-87-0

329198-87-0

Light yellow to yellow solid

4.1

101Ų

O=C(C1=CC=C([N+]([O-])=O)O1)NC2=CC=C3C(OC4=CC=CC=C34)=C2

URUVDCCYSJEGQQ-UHFFFAOYSA-N

InChI=1S/C17H10N2O5/c20-17(14-7-8-16(24-14)19(21)22)18-10-5-6-12-11-3-1-2-4-13(11)23-15(12)9-10/h1-9H,(H,18,20)

N-(Dibenzo[b,d]furan-3-yl)-5-nitrofuran-2-carboxamide

C178 C 178 C-178

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~41.67 mg/mL (~129.30 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)