Pyridone 6

Biological Activity

Pyridone 6 displays potent inhibitory activity against JAK1 (IC50 = 15 nM for murine JAK1), JAK2 (IC50 = 1 nM), JAK3 (Ki = 5 nM), and Tyk2 (IC50 = 1 nM). JAK1 (Janus kinase 1), JAK2 and JAK3 belong to the family of non-receptor janus tyrosine kinases, which regulate a spectrum of cellular functions downstream of activated cytokine receptors in the lympho-hematopoietic system. Immunological stimuli, such as interferons and cytokines, induce recruitment of STAT transcription factors to cytokine receptor-associated JAK1, JAK2 and JAK3. Pyridone 6 inhibited osteoclast differentiation in mouse bone marrow macrophage (BMM) cultures stimulated by the receptor activator of nuclear factor-kappaB (NF-kappaB) ligand (RANKL) and co-cultures of bone marrow cells and osteoblasts. Pyridone 6 suppressed the expression of c-Fos and nuclear factor of activated T cells (NFAT) c1 in BMMs. It also inhibited the bone resorptive activity of mature osteoclasts that was accompanied by disruption of actin rings. Pyridone 6 also suppressed I-kappaB degradation and extracellular signal-regulated kinase (ERK) in mature osteoclasts, suggesting that these are the key molecules that pyridone 6 targets in the inhibition of osteoclast function.

Conversion of different model animals based on BSA (Value based on data from FDA Draft Guidelines)

Species	Mouse	Rat	Rabbit	Guinea pig	Hamster	Dog
Weight (kg)	0.02	0.15	1.8	0.4	0.08	10
Body Surface Area (m2)	0.007	0.025	0.15	0.05	0.02	0.5
Km factor	3	6	12	8	5	20

Animal A (mg/kg) = Animal B (mg/kg) multiplied by	Animal B Km
	Animal A Km

For example, to modify the dose of resveratrol used for a mouse (22.4 mg/kg) to a dose based on the BSA for a rat, multiply 22.4 mg/kg by the K_m factor for a mouse and then divide by the K_m factor for a rat. This calculation results in a rat equivalent dose for resveratrol of 11.2 mg/kg.

Chemical Information

References

Pyridone 6, a pan-JAK inhibitor, ameliorates allergic skin inflammation of NC/Nga mice via suppression of Th2 and enhancement of Th17.
Nakagawa R, et al. J Immunol. 2011 Nov 1;187(9):4611-20. PMID: 21957150.

Effects of a Janus kinase inhibitor, pyridone 6, on airway responses in a murine model of asthma.
Matsunaga Y, et al. Biochem Biophys Res Commun. 2011 Jan 7;404(1):261-7. PMID: 21111712.

Structural and thermodynamic characterization of the TYK2 and JAK3 kinase domains in complex with CP-690550 and CMP-6.
Chrencik JE, et al. J Mol Biol. 2010 Jul 16;400(3):413-33. PMID: 20478313.