A critical role for IRAK4 kinase activity in Toll-like receptor-mediated innate immunity.

IRAK4 is a member of IL-1 receptor (IL-1R)-associated kinase (IRAK) family and has been shown to play an essential role in Toll-like receptor (TLR)-mediated signaling. We recently generated IRAK4 kinase-inactive knock-in mice to examine the role of kinase activity of IRAK4 in TLR-mediated signaling pathways. The IRAK4 kinase-inactive knock-in mice were completely resistant to lipopolysaccharide (LPS)- and CpG-induced shock, due to impaired TLR-mediated induction of proinflammatory cytokines and chemokines. Although inactivation of IRAK4 kinase activity did not affect the levels of TLR/IL-1R-mediated nuclear factor kappaB activation, a reduction of LPS-, R848-, and IL-1-mediated mRNA stability contributed to the reduced cytokine and chemokine production in bone marrow-derived macrophages from IRAK4 kinase-inactive knock-in mice. Both TLR7- and TLR9-mediated type I interferon production was abolished in plasmacytoid dendritic cells isolated from IRAK4 knock-in mice. In addition, influenza virus-induced production of interferons in plasmacytoid DCs was also dependent on IRAK4 kinase activity. Collectively, our results indicate that IRAK4 kinase activity plays a critical role in TLR-dependent immune responses.

Expression and characterization of a mutant recombinant blood coagulation factor VIII (rFVIII (m)).

In an earlier study, a site directed mutant rFVIII (rFVIII(m), Arg(336) --> Gln(336)) expressed in baculovirus-insect cell (Sf9) system was found to sustain high level activity during incubation at 37 degrees celsius for 24 h while the cofactor activity of normal plasma was declined steadily. In this study, a mutant B-domain deleted rFVIII(m), Arg(336) --> Gln(336) expressed in baculovirus-insect cell (Sf9) system was characterized for its enzymatic and chemical properties. The expressed rFVIII(m) and plasma FVIII (pFVIII) were purified by immunoaffinity column chromatography and identified by Western blot analysis. The partially purified rFVIII(m) exhibited cofactor specific activity of 2.01 x 10(3)units/mg protein. The molecular weight of rFVIII(m) ranged between 40 to 150 kDa with a major band at 150 kDa. Treatment of both rFVIII(m) and pFVIII with thrombin increased their cofactor activity in a similar pattern. Treatment of both the activated rFVIII(m) and native FVIII with APC decreased their cofactor activities, however, the former exhibited a slower decrease than the latter, although no significant difference was present. rFVIII(m) formed a complex with vWF, resulting in a stabilized form, and the lag period of thrombin-mediated activating was extended by vWF association. These results implicated that rFVIII(m) expressed in baculovirus-insect cell system had a comparable capacity as FVIII cofactor activity and might be a good candidate for the FVIII replacement therapy for hemophilia A patients.

Pregnancy in postpartum estrus induces inflammatory milk production and catagen specific pup skin inflammation in interleukin-10 deficient mice.

BACKGROUND: The interleukin 10 deficient mice (IL-10(-/-)) showed high incidence of pup alopecia compared to other strains, and pup alopecia was caused by skin inflammation and was recoverable. Pup alopecia of B6.IL-10(-/-) might be related with maternal factor and interleukin-10 deficient phenotype. OBJECTIVE: The objectives of this study were elucidating of maternal factors for inflammatory milk production and characterization of pup alopecia in IL-10(-/-) mice. METHODS: Incidences of pup alopecia were analyzed with 13 breeding cases. Comparison between control and alopecia pups and its dams, were conducted with histological examination (H&E, TUNEL assay, immunohistochemistry for F4/80, iNOS, CD206, Gr-1, CD4, CD8, CD11c and CD326), fostering test, forced weaning test, qPCR for tyrosine hydroxylase, flow cytometry, IL-10 inhibition test, BMDM stimulation test and LC/MS analysis. RESULTS: Presence of pregnancy in postpartum estrus showed significant correlation with inflammatory milk production and mammary gland involution in B6.IL-10(-/-) mice. There were no different mass in inflammatory milk, but different ionization intensity was detected. Inflammatory milk directly induced hepatocyte steatosis, catagen stage specific hair breaking and alopeicia in pups. Histologically, hypertropy of outer root sheath and macrophage/neutrophil infiltration were typical. CONCLUSION: B6.IL-10(-/-) dam with stress such as PPE could produce untimely mammary gland involution and inflammatory milk production. Interleukin 10 is important for maternal stress regulation and protecting inflammatory milk production, also influence severity of pup skin inflammation and alopecia. Remarkably, inflammatory milk induced hepatocyte steatosis, and it could indicate there is abnormal lipid metabolism. This was first report for catagen specific alopecia in mouse.

The Porcine Aortic Tissue Culture System in vitro for Stem Cell Research.

BACKGROUND AND OBJECTIVES: Due to the shortage of human donors for transplantation, the use of animal organs for xenotransplantation has come into great interest. Xeno-derived vessels and cardiac valves would be possible alternatives for the patient suffering from cardiovascular diseases. Therefore, we established in vitro culture system of a porcine vessel that could be helpful for the research of xenograft and stem cell research. METHODS AND RESULTS: We primarily isolated porcine thoracic aorta, cultured square-shaped pieces up to 17 days and analyzed its morphology and characters. The endothelial cells were primarily isolated from cultured porcine aortic pieces and their morphology, function and character were analyzed in order to confirm them as endothelial cells at day 3, 4, 8, 10 and 17. Even at day 17, the morphology exhibited the intact endothelial layer as well as specifically expressed CD31 and von Willebrand factor. The morphology of primarily isolated cells from cultured tissues was identical as an endothelial cell. By flow cytometry analysis, more than 80% of the isolated cells expressed CD31 and up to 80% took up acetyl low density lipoprotein (ac-LDL) until day 10 of tissue culture period even though it decreased to about 50% at day 17 that means they not only showed typical endothelial cell characters but also functioned properly. CONCLUSIONS: We successfully established and optimized a porcine vascular tissue in vitro culture system that could be a valuable model for in vitro study of xenotransplantation and stem cell research.