Caerulomycin A (also known as Cerulomycin, CaeA) is a novel bipyridyl compound that induces generation of T cells, enhances TGF-β-Smad3 protein signaling via suppressing interferon-γ-induced STAT1 signaling. It is also a toxin that inhibits growth of Entamoeba. It has antifungal and antibiotic activity, and can be used in autoimmune diseases. Cytokines play a very important role in the regulation of immune homeostasis. Regulatory T cells (Tregs) responsible for the generation of peripheral tolerance are under the tight regulation of the cytokine milieu. It was observed that Caerulomycin A substantially up-regulated the pool of Tregs, as evidenced by an increased frequency of CD4(+) Foxp3(+) cells. In addition, CaeA significantly suppressed the number of Th1 and Th17 cells, as supported by a decreased percentage of CD4(+)/IFN-γ(+) and CD4(+)/IL-17(+) cells, respectively.

Physicochemical Properties

Molecular Formula	C12H11N3O2
Molecular Weight	229.23
Exact Mass	229.085
Elemental Analysis	C, 62.87; H, 4.84; N, 18.33; O, 13.96
CAS #	21802-37-9
Related CAS #	21802-37-9
PubChem CID	135514797
Appearance	White to off-white solid powder
Density	1.23g/cm3
Boiling Point	400.4ºC at 760mmHg
Flash Point	195.9ºC
LogP	1.96
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	3
Heavy Atom Count	17
Complexity	260
Defined Atom Stereocenter Count	0
SMILES	COC1=CC(C2=NC=CC=C2)=NC(/C=N/O)=C1
InChi Key	JCTRJRHLGOKMCF-RIYZIHGNSA-N
InChi Code	InChI=1S/C12H11N3O2/c1-17-10-6-9(8-14-16)15-12(7-10)11-4-2-3-5-13-11/h2-8,16H,1H3/b14-8+
Chemical Name	(E)-4-methoxy-[2,2'-bipyridine]-6-carbaldehyde oxime
Synonyms	Carulomycin A; AC1NTHG8; AC1N-THG8; AC1N THG8 NSC-114341; NSC114341; NSC 114341; HE185727; HE 185727; HE-185727; Caerulomycin A
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Antifungal;TGF-β-Smad3
ln Vitro	Caerulomycin A (CaeA), in inducing the generation of Tregs. It was observed that CaeA substantially up-regulated the pool of Tregs, as evidenced by an increased frequency of CD4(+) Foxp3(+) cells. In addition, CaeA significantly suppressed the number of Th1 and Th17 cells, as supported by a decreased percentage of CD4(+)/IFN-γ(+) and CD4(+)/IL-17(+) cells, respectively. Furthermore, we established the mechanism and observed that CaeA interfered with IFN-γ-induced STAT1 signaling by augmenting SOCS1 expression. An increase in the TGF-β-mediated Smad3 activity was also noted. Furthermore, CaeA rescued Tregs from IFN-γ-induced inhibition. These results were corroborated by blocking Smad3 activity, which abolished the CaeA-facilitated generation of Tregs. In essence, our results indicate a novel role of CaeA in inducing the generation of Tregs. This finding suggests that CaeA has enough potential to be considered as a potent future drug for the treatment of autoimmunity.[1]
Cell Assay	Th1 and Th17 cells were treated with phorbol 12-myristate 13-acetate (40 nm) and ionomycin (1 μm) for 2 h. To block cytokine secretion, brefeldin A (10 μg/ml) was added. Later, and cells were incubated further for 3 h. Tregs, Th1, and Th17 cells were cultured with different concentrations of CaeA (0–0.15 μm). The modulation in the frequency of Tregs, Th1, and Th17 cells was analyzed by flow cytometry.[1] A booster dose of bovine collagen type II in incomplete Freund adjuvant was injected on day 21. Later, CaeA (1 and 10 mg/kg body weight) and 0.5% carboxyl methyl cellulose emulsion in water was administered daily for 50 days, and animals were monitored every day for arthritis symptoms. [1] The IFN-γ-mediated STAT1 response was measured by initially incubating CD4 T cells with CaeA (0–0.31 μm) for 24 h, followed by IFN-γ (200 units/ml) stimulation for 30 min. To evaluate the TGF-β-mediated Smad3 response, CD4 T cells were incubated initially with CaeA (0–0.31 μm) for 24 h, followed by IFN-γ (200 units/ml) treatment for 48 h. Later, cells were pulsed with TGF-β (2 ng/ml) for 1 h. [1] CD4 T cells stimulated with anti-CD3 (2 μg/ml) and CD28 (1 μg/ml) Abs were cultured with CaeA (0–0.31 μm) for 72 h. Later, cells were pelleted and resuspended in JC-1 (5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolylcarbocyanine iodide) medium (2.5 μg/ml). The cultures were incubated at room temperature for 15–20 min in the dark. Later, cells were washed with flow cytometry staining buffer (2% FBS in PBS) and acquired immediately using a flow cytometer (FACSCalibur), and then the analysis was done using FACSDiva software. [1]
References	[1]. Caerulomycin A enhances transforming growth factor-β (TGF-β)-Smad3 protein signaling by suppressing interferon-γ (IFN-γ)-signal transducer and activator of transcription 1 (STAT1) protein signaling to expand regulatory T cells (Tregs). J Biol Chem. 2014 Jun 20;289(25):17515-28.
Additional Infomation	Caerulomycin A is a pyridine alkaloid that is 2,2'-bipyridine substituted by a methoxy group at position 4 and a (E)-(hydroxyimino)methyl group at position 6. Isolated from the marine-derived actinomycete Actinoalloteichus cyanogriseus, it exhibits antineoplastic activity. It has a role as an antineoplastic agent, a marine metabolite and a bacterial metabolite. It is an aldoxime, an aromatic ether, a member of bipyridines and a pyridine alkaloid. It derives from a hydride of a 2,2'-bipyridine. Cerulomycin has been reported in Actinoalloteichus cyanogriseus with data available.

Solubility Data

Solubility (In Vitro)

DMSO : ~150 mg/mL (~654.34 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (10.91 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (10.91 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. 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. Solubility in Formulation 3: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.5 mg/mL (10.91 mM)  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	4.3624 mL	21.8122 mL	43.6243 mL
	5 mM	0.8725 mL	4.3624 mL	8.7249 mL
	10 mM	0.4362 mL	2.1812 mL	4.3624 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.