Publications

Cytokines interleukin (IL) 12 and 23 play critical roles in linking innate and adaptive immune responses. They are members of heterodimeric cytokines, sharing a subunit p40. Although IL12/23 p40 is mainly induced in macrophages and dendritic cells (DCs) after stimulation with microbial Toll-like receptor ligands, methods to monitor the cells that produce IL12/23 p40 in vivo are limited. Recently, the mouse model to track p40-expressing cells with fluorescent reporter, yellow fluorescent protein, has been developed. Macrophages and DCs from these mice faithfully reported p40 induction using the fluorescent marker. Here we took advantage of these reporter mice to screen bio-compounds for p40-inducing activity. After screening hundreds of compounds, we found several extracts inducing IL12/23 p40 gene expression. Treatment of DCs with these extracts induced the expression of MHC class II and co-stimulatory molecules, which implies that these might be useful as adjuvants. Next, the in vivo target immune cells of candidate compounds were examined. The reporter system can be useful to identify cells producing IL12 or IL23 in vivo as well as in vitro. Thus, our cytokine reporter system proved to be a valuable reagent for screening for immunostimulatory molecules and identification of target cells in vivo.

Matrix metalloproteinase-2 (MMP-2) plays an essential role in angiogenesis and arteriogenesis, two processes critical to restoration of tissue perfusion after ischemia. MMP-2 expression is increased in tissue ischemia, but the responsible mechanisms remain unknown. We studied the transcriptional activation of the MMP-2 gene in a model of hindlimb ischemia by using various MMP-2-lacZ reporter mice and chromatin immunoprecipitation. MMP-2 activity and mRNA were increased after hindlimb ischemia. Mice with targeted deletion of MMP-2 had impaired restoration of perfusion and a high incidence of limb gangrene, indicating that MMP-2 plays a critical role in ischemia-induced revascularization. Ischemia induced the expression and binding of c-Fos, c-Jun, JunB, FosB, and Fra2 to a noncanonical activating protein-1 (AP-1) site present in the MMP-2 promoter and decreased binding of the transcriptional repressor JunD. Ischemia also activated the expression and binding of p53 to an adjacent enhancer site (RE-1) and increased expression and binding of nuclear factor of activated T-cells-c2 to consensus sequences within the first intron. Deletion of either the 5' AP-1/RE-1 region of the promoter or substitution of the first intron abolished ischemia-induced MMP-2 transcription in vivo. Thus, AP-1 transcription factors and intronic activation by nuclear factor of activated T-cells-c2 act in concert to drive ischemia-induced MMP-2 transcription. These findings define a critical role for MMP-2 in ischemia-induced revascularization and identify both previously uncharacterized regulatory elements within the MMP-2 gene and the cognate transcription factors required for MMP-2 activation in vivo after tissue ischemia.

Atorvastatin (ATV) is primarily metabolized by CYP3A in the liver to form two active hydroxy metabolites. Therefore, the sequential transport system governed by hepatic uptake and efflux transporters is important for the drug disposition and metabolism. Here, we assessed the interaction of ATV with hepatic uptake transporter organic anion transporting polypeptide (Oatp) and efflux transporter multidrug resistance associated protein 2 (MRP2/Mrp2) in vitro and ex situ using the isolated perfused rat liver (IPRL). Rifampicin (RIF) was chosen as an inhibitor for Oatp in both uptake and IPRL studies. Its inhibitory effects on MRP2 and metabolism were also tested using MRP2-overexpressing cells and rat microsomes, respectively. Our results indicate that RIF effectively inhibits the Oatp-mediated uptake of ATV and its metabolites. Inhibition on MRP2-mediated efflux of ATV was also observed at a high RIF concentration. Compared with ATV alone in the IPRL, the area under the curve(s) (AUC) of ATV was significantly increased by RIF, whereas the AUC of both metabolites were also increased in a concentration-dependent manner. However, the extent of metabolism was significantly reduced, as reflected by the reduced amounts of metabolites detected in RIF-treated livers. In conclusion, inhibition of Oatp-mediated uptake seems to be the major determinant for interaction between ATV and RIF. Metabolites of ATV were subject to Oatp-mediated uptake as well, suggesting that they undergo a similar disposition pathway as the parent drug. These data emphasize the relevance of uptake transporter as being one of the major players in hepatic drug elimination, even for substrates that undergo metabolism.

Latinos are the largest minority population in the United States. Although usually classified as a single ethnic group by researchers, Latinos are heterogeneous from cultural, socioeconomic, and genetic perspectives. From a cultural and social perspective, Latinos represent a wide variety of national origins and ethnic and cultural groups, with a full spectrum of social class. From a genetic perspective, Latinos are descended from indigenous American, European, and African populations. We review the historical events that led to the formation of contemporary Latino populations and use results from recent genetic and clinical studies to illustrate the unique opportunity Latino groups offer for studying the interaction between racial, genetic, and environmental contributions to disease occurrence and drug response.