Lipids, inflammation and atherosclerosis

In dit promotieonderzoek is zijn de effecten van vetstapeling en ontstekingsreactie tijdens het proces van atherosclerose. We hebben aangetoond dat het ontstekingsremmende eiwit interleukine-9, een stof die door bepaalde immunologische cellen geproduceerd wordt, een remmende werking heeft op het ontstaan van atherosclerose in het algemeen en van vetstapeling in macrofagen in het bijzonder. Aan de andere kant blijkt uit mijn promotieonderzoek dat vetstapeling van macrofagen de gevoeligheid van deze cellen voor ontstekingen beïnvloedt. LPS is in staat om een zeer sterke ontstekingsreactie te stimuleren en om de expressie van verschillende genen die betrokken zijn bij vetstapeling te beïnvloeden. Door gebruik te maken van muizen die geen scavenger receptor BI (SR-BI) tot expressie brengen, hebben we aangetoond dat SR-BI beschermd tegen de door LPS gestimuleerde ontstekingsreactie. Tevens blijkt dat een dieet met een hoog cholesterol gehalte een grote invloed heeft op parenchymcellen in de lever. Voornamelijk FABP5 en vier nieuwe vetzuurbindende eiwitten lijken een belangrijke rol te spelen in de reactie van deze cellen op het dieet. Ook het ontstekingremmende interleukine 10, waarvan bekend is dat het atherosclerose kan remmen en een verlaging van cholesterol in het bloed kan veroorzaken, beïnvloedt vele genen betrokken bij vethuishouding in parenchymcellen van de lever

Scavenger receptor class B type I-mediated uptake of serum cholesterol is essential for optimal adrenal glucocorticoid production

Biopharmaceutic

Microarray analysis indicates an important role for FABP5 and putative novel FABPs on a Western-type diet

Biopharmaceutic

A national survey of managed honey bee 2011-12 winter colony losses in the United States: results from the Bee Informed Partnership

Estimates of winter loss for managed honey bee (Apis mellifera) colonies are an important measure of honey bee health and productivity. We used data from 5,500 US beekeepers (5,244 backyard, 189 sideline and 67 commercial beekeepers) who responded to the April 2012 Bee Informed Partnership Winter Colony Loss Survey and calculated loss as the difference in the number of colonies between October 1, 2011 and April 1, 2012, adjusting for increases and decreases over that period. In the US, the total colony loss was 22.5% for the 2011-12 winter; 45.1% (n = 2,482) of respondents reported no colony loss. Total loss during 2011-12 was substantially lower than loss during 2010-11 (29.9%). Of the 4,484 respondents who kept bees in 2010-11 and 2011-12, 72.0% reported that the loss during 2011-12 was smaller or similar to the loss during 2010-11. There was substantial variation in total loss by state (range 6.2% to 47.7%). The average loss per beekeeping operation was 25.4%, but the average loss was not significantly different by operation type (backyard, sideline, commercial). The average self-reported acceptable loss per respondent was 13.7%; 46.8% (n = 2,259) of respondents experienced winter colony losses in excess of the average acceptable loss. Of beekeepers who reported losing at least one colony during 2011-12, the leading self-identified causes of mortality were weak condition in the fall and queen failure. Respondents who indicated poor wintering conditions, CCD, or pesticides as a leading cause of mortality suffered a higher average loss when compared to beekeepers who did not list these as potential causes.Keywords: Mortality, Colony losses, USA, Honey bee, Overwinter, 2011-1

PPS, a Large Multidomain Protein, Functions with Sex-Lethal to Regulate Alternative Splicing in Drosophila

Alternative splicing controls the expression of many genes, including the Drosophila sex determination gene Sex-lethal (Sxl). Sxl expression is controlled via a negative regulatory mechanism where inclusion of the translation-terminating male exon is blocked in females. Previous studies have shown that the mechanism leading to exon skipping is autoregulatory and requires the SXL protein to antagonize exon inclusion by interacting with core spliceosomal proteins, including the U1 snRNP protein Sans-fille (SNF). In studies begun by screening for proteins that interact with SNF, we identified PPS, a previously uncharacterized protein, as a novel component of the machinery required for Sxl male exon skipping. PPS encodes a large protein with four signature motifs, PHD, BRK, TFS2M, and SPOC, typically found in proteins involved in transcription. We demonstrate that PPS has a direct role in Sxl male exon skipping by showing first that loss of function mutations have phenotypes indicative of Sxl misregulation and second that the PPS protein forms a complex with SXL and the unspliced Sxl RNA. In addition, we mapped the recruitment of PPS, SXL, and SNF along the Sxl gene using chromatin immunoprecipitation (ChIP), which revealed that, like many other splicing factors, these proteins bind their RNA targets while in close proximity to the DNA. Interestingly, while SNF and SXL are specifically recruited to their predicted binding sites, PPS has a distinct pattern of accumulation along the Sxl gene, associating with a region that includes, but is not limited to, the SxlPm promoter. Together, these data indicate that PPS is different from other splicing factors involved in male-exon skipping and suggest, for the first time, a functional link between transcription and SXL–mediated alternative splicing. Loss of zygotic PPS function, however, is lethal to both sexes, indicating that its role may be of broad significance

Species differences in the interaction between LPS and paracetamol, diclofenac and ketoconazole in precision-cut liver slices

Idiosyncratic drug reactions (IDRs) are adverse drug reactions that occur without obvious relation to time or dose and are unpredictable and sporadic. IDRs may arise due to inflammatory episodes concomitant with exposure to the drug that renders the liver more sensitive to injury resulting in increased toxicity. The aim of the study is to investigate the influence of an inflammatory reaction on the toxicity of drugs and species differences therein using human and animal precision- cut liver slices (PCLS). The technology of PCLS is receiving increased attention as a potential in vitro toxicological model because PCLS retain the normal tissue architecture of an intact liver where all cell types are present in their natural environment. Mouse and human PCLS were incubated with paracetamol (APAP), diclofenac (DF) or ketoconazole (KCZ) alone or in the presence of lipopolysaccharide (LPS) to induce an inflammatory reaction. Cell viability (ATP, liver enzyme leakage) and cytokine production were assessed. Both APAP and DF, but not KCZ, were more toxic in mouse than human. LPS had no influence on APAP and DF toxicity in mouse or human when assessed by viability tests. However, APAP and DF decreased the LPS-induced IL-1β production in both species while IL- 6 production was only decreased in mouse PCLS. APAP increased LPS-induced TNF-α production in mouse but strongly reduced it in human PCLS, while in both species TNF-α production was increased by DF alone, but not by APAP alone. In contrast to APAP and DF, KCZ toxicity was increased in the presence of a non-toxic dose of LPS in mouse PCLS, while KCZ did not decrease the LPSinduced IL-1β production. In conclusion, KCZ toxicity is aggravated by LPS and clear species differences were identified in the effect of APAP, DF and KCZ on the inflammatory reactions induce by LPS. The role of cytokines in the effect of LPS on the toxicity of KCZ needs to be further investigated. Based on these results PCLS appear promising as an in vitro translational model to unravel the mechanism behind IDRs and to find biomarkers that can detect them