Oligo targeting for profiling drug resistance mutations in the parasitic trypanosomatids.

Trypanosomatids cause the neglected tropical diseases, sleeping sickness, Chagas disease and the leishmaniases. Studies on these lethal parasites would be further facilitated by new and improved genetic technologies. Scalable precision editing methods, for example, could be used to improve our understanding of potential mutations associated with drug resistance, a current priority given that several new anti-trypanosomal drugs, with known targets, are currently in clinical development. We report the development of a simple oligo targeting method for rapid and precise editing of priority drug targets in otherwise wild type trypanosomatids. In Trypanosoma brucei, approx. 50-b single-stranded oligodeoxynucleotides were optimal, multiple base edits could be incorporated, and editing efficiency was substantially increased when mismatch repair was suppressed. Resistance-associated edits were introduced in T. brucei cyclin dependent kinase 12 (CRK12, L482F) or cleavage and polyadenylation specificity factor 3 (N232H), in the Trypanosoma cruzi proteasome ß5 subunit (G208S), or in Leishmania donovani CRK12 (G572D). We further implemented oligo targeting for site saturation mutagenesis, targeting codon G492 in T. brucei CRK12. This approach, combined with amplicon sequencing for codon variant scoring, revealed fourteen resistance conferring G492 edits encoding six distinct amino acids. The outputs confirm on-target drug activity, reveal a variety of resistance-associated mutations, and facilitate rapid assessment of potential impacts on drug efficacy.

Heteromeric HSFA2/HSFA3 complexes drive transcriptional memory after heat stress in Arabidopsis.

Adaptive plasticity in stress responses is a key element of plant survival strategies. For instance, moderate heat stress (HS) primes a plant to acquire thermotolerance, which allows subsequent survival of more severe HS conditions. Acquired thermotolerance is actively maintained over several days (HS memory) and involves the sustained induction of memory-related genes. Here we show that FORGETTER3/ HEAT SHOCK TRANSCRIPTION FACTOR A3 (FGT3/HSFA3) is specifically required for physiological HS memory and maintaining high memory-gene expression during the days following a HS exposure. HSFA3 mediates HS memory by direct transcriptional activation of memory-related genes after return to normal growth temperatures. HSFA3 binds HSFA2, and in vivo both proteins form heteromeric complexes with additional HSFs. Our results indicate that only complexes containing both HSFA2 and HSFA3 efficiently promote transcriptional memory by positively influencing histone H3 lysine 4 (H3K4) hyper-methylation. In summary, our work defines the major HSF complex controlling transcriptional memory and elucidates the in vivo dynamics of HSF complexes during somatic stress memory.

FORGETTER2 protein phosphatase and phospholipase D modulate heat stress memory in Arabidopsis.

Plants can mitigate environmental stress conditions through acclimation. In the case of fluctuating stress conditions such as high temperatures, maintaining a stress memory enables a more efficient response upon recurring stress. In a genetic screen for Arabidopsis thaliana mutants impaired in the memory of heat stress (HS) we have isolated the FORGETTER2 (FGT2) gene, which encodes a type 2C protein phosphatase (PP2C) of the D-clade. Fgt2 mutants acquire thermotolerance normally; however, they are defective in the memory of HS. FGT2 interacts with phospholipase D α2 (PLDα2), which is involved in the metabolism of membrane phospholipids and is also required for HS memory. In summary, we have uncovered a previously unknown component of HS memory and identified the FGT2 protein phosphatase and PLDα2 as crucial players, suggesting that phosphatidic acid-dependent signaling or membrane composition dynamics underlie HS memory.

BRUSHY1/TONSOKU/MGOUN3 is required for heat stress memory.

Plants encounter biotic and abiotic stresses many times during their life cycle and this limits their productivity. Moderate heat stress (HS) primes a plant to survive higher temperatures that are lethal in the naïve state. Once temperature stress subsides, the memory of the priming event is actively retained for several days preparing the plant to better cope with recurring HS. Recently, chromatin regulation at different levels has been implicated in HS memory. Here, we report that the chromatin protein BRUSHY1 (BRU1)/TONSOKU/MGOUN3 plays a role in the HS memory in Arabidopsis thaliana. BRU1 is also involved in transcriptional gene silencing and DNA damage repair. This corresponds with the functions of its mammalian orthologue TONSOKU-LIKE/NFΚBIL2. During HS memory, BRU1 is required to maintain sustained induction of HS memory-associated genes, whereas it is dispensable for the acquisition of thermotolerance. In summary, we report that BRU1 is required for HS memory in A. thaliana, and propose a model where BRU1 mediates the epigenetic inheritance of chromatin states across DNA replication and cell division.

Transcriptomic basis for reinforcement of elm antiherbivore defence mediated by insect egg deposition.

Plant responses to insect egg depositions are known to shape subsequent defensive responses to larvae hatching from the eggs. Elm (Ulmus minor) leaves, on which elm leaf beetles laid their eggs, mount a more efficient defence against larvae hatching from the eggs. However, the molecular mechanisms of this egg-mediated, improved defence are insufficiently understood and have so far only been studied in annual plants. We analysed the dynamics of transcriptomic changes in larval feeding-damaged elm leaves with and without prior egg deposition using de novo assembled RNA-seq data. Compared to egg-free leaves, egg deposition-treated leaves showed earlier and/or faster transcriptional regulations, as well as slightly enhanced differential transcriptional regulation after the onset of larval feeding. These early responding transcripts were overrepresented in gene ontology terms associated with post-translational protein modification, signalling and stress (defence) responses. We found evidence of transcriptional memory in initially egg deposition-induced transcripts whose differential expression was reset prior to larval hatching, but was more rapidly induced again by subsequent larval feeding. This potential memory effect of prior egg deposition, as well as the earlier/faster and enhanced feeding-induced differential regulation of transcripts in egg deposition-treated leaves, may contribute to the egg-mediated reinforcing effect on the elm's defence against larvae. Hence, our study shows that a plant's experience of a stress-indicating environmental cue (here: insect eggs) can push the dynamics of the plant's transcriptomic response to subsequent stress (here: larval feeding). Such experience-mediated acceleration of a stress-induced plant response may result in improved stress resistance.

Gradual and Acute Temperature Rise Induces Crossing Endocrine, Metabolic, and Immunological Pathways in Maraena Whitefish (Coregonus maraena).

The complex and still poorly understood nature of thermoregulation in various fish species complicates the determination of the physiological status on the basis of diagnostic marker genes and indicative molecular pathways. The present study aimed to compare the physiological impacts of both gradual and acute temperature rise from 18 to 24°C on maraena whitefish in aquaculture. Microarray-based transcriptome profiles in the liver, spleen and kidney of heat-stressed maraena whitefish revealed the modulation of a significantly higher number of genes in those groups exposed to gradually rising temperatures compared with the acutely stressed groups, which might reflect early adaptation mechanisms. Moreover, we suggest a common set of 11 differentially expressed genes that indicate thermal stress induced by gradual or acute temperature rise in the three selected tissues. Besides the two pathways regulated in both data sets unfolded protein response and aldosterone signaling in epithelial cells, we identified unique tissue- and stress type-specific pathways reflecting the crossroads between signal transduction, metabolic and immunologic pathways to cope with thermal stress. In addition, comparing lists of differentially regulated genes with meta-analyzed published data sets revealed that "acute temperature rise"-responding genes that encode members of the HSP70, HSP90, and HSP40 families; their functional homologs; co-chaperones and stress-signal transducers are well-conserved across different species, tissues and/or cell types and experimental approaches.

Arabidopsis FORGETTER1 mediates stress-induced chromatin memory through nucleosome remodeling.

Plants as sessile organisms can adapt to environmental stress to mitigate its adverse effects. As part of such adaptation they maintain an active memory of heat stress for several days that promotes a more efficient response to recurring stress. We show that this heat stress memory requires the activity of the FORGETTER1 (FGT1) locus, with fgt1 mutants displaying reduced maintenance of heat-induced gene expression. FGT1 encodes the Arabidopsis thaliana orthologue of Strawberry notch (Sno), and the protein globally associates with the promoter regions of actively expressed genes in a heat-dependent fashion. FGT1 interacts with chromatin remodelers of the SWI/SNF and ISWI families, which also display reduced heat stress memory. Genomic targets of the BRM remodeler overlap significantly with FGT1 targets. Accordingly, nucleosome dynamics at loci with altered maintenance of heat-induced expression are affected in fgt1. Together, our results suggest that by modulating nucleosome occupancy, FGT1 mediates stress-induced chromatin memory.

Transcriptome sequencing of maraena whitefish (Coregonus maraena).

Maraena whitefish (Coregonus maraena, Bloch, 1779) is a high-quality food fish belonging to the family Salmonidae with considerable economic relevance in the Baltic area. Aquaculture of this species is fundamental for its successful conservation and thus sustainable fisheries. Robust fishes obtained from breeding lines build the basis for effective aquaculture. Doubtless, the utilization of transcriptome sequencing and identification of genetic markers contribute to this aim. 454 FLX Titanium Sequencing provided 1.31 million sequence reads representing a first insight into the C. maraena transcriptome. The 454 Newbler Assembly arranged 29,094 contigs with an average length of 798bp. We found a whole series of transcripts highly probably resulting from ancient genome duplication and annotated 2887 different transcripts with an average length of 812bp. Functional annotation obtained a transcript composition predominantly comprising enzyme-coding genes.

Toll-like receptors in maraena whitefish: Evolutionary relationship among salmonid fishes and patterns of response to Aeromonas salmonicida.

Toll-like receptors (TLRs) interact directly with particular pathogenic structures and are thus highly important to innate immunity. The present manuscript characterises a suite of 14 TLRs in maraena whitefish (Coregonus maraena), a salmonid species with increasing importance for aquaculture. Whitefish TLRs were structurally and evolutionary analysed. The results revealed a close relationship with TLRs from salmonid fish species rainbow trout and Atlantic salmon. Profiling the baseline expression of TLR genes in whitefish indicated that mainly members of the TLR11 family were highly expressed across all investigated tissues. A stimulation model with inactivated Aeromonas salmonicida was used to induce inflammation in the peritoneal cavity of whitefish. This bacterial challenge induced the expression of pro-inflammatory cytokine genes and evoked a strong influx of granulated cells of myeloid origin into the peritoneal cavity. As a likely consequence, the abundance of TLR-encoding transcripts increased moderately in peritoneal cells, with the highest levels of transcripts encoding non-mammalian TLR22a and a soluble TLR5 variant. In the course of inflammation, the proportion of granulated cells increased in peripheral blood accompanied by elevated TLR copy numbers in spleen and simultaneously reduced TLR copy numbers in head kidney at day 3 post-stimulation. Altogether, the present study provides in-vivo evidence for relatively modest TLR response patterns, but marked trafficking of myeloid cells as an immunophysiological consequence of A. salmonicida inflammation in whitefish. The present results contribute to improved understanding of the host-pathogen interaction in salmonid fish.

Adverse Husbandry of Maraena Whitefish Directs the Immune System to Increase Mobilization of Myeloid Cells and Proinflammatory Responses.

Adverse life circumstances evoke a common "conserved transcriptional response to adversity" (CTRA) in mammalian leukocytes. To investigate whether this pattern is preserved in lower vertebrates, maraena whitefish (Coregonus maraena) were exposed for 9 days to different stocking densities: ~10 kg/m3 (low density), ~33 kg/m3 (moderate), ~60 kg/m3 (elevated), and ~100 kg/m3 (high). Transcriptome profiling in the liver and kidney of individuals from each group suggested that crowding conditions activate stress-related signaling and effector pathways. Remarkably, about one-quarter of the genes differentially expressed under crowding conditions were involved in the activation of immune pathways such as acute-phase response and interleukin/TNF signaling attended by the simultaneous reduction of antiviral potency. Network analysis confirmed the complex interdigitation of immune- and stress-relevant pathways with interleukin-1 playing a central role. Antibody-based techniques revealed remarkable changes in the blood composition of whitefish and demonstrated the correlation between increasing stocking densities and elevated number of myeloid cells together with the increased phagocytic activity of peripheral blood leukocytes. In line with current studies in mammals, we conclude that crowding stress triggers in whitefish hallmarks of a CTRA, indicating that the stress-induced molecular mechanisms regulating the immune responses not only are conserved within mammals but were established earlier in evolution.

A hit-and-run heat shock factor governs sustained histone methylation and transcriptional stress memory.

In nature, plants often encounter chronic or recurring stressful conditions. Recent results indicate that plants can remember a past exposure to stress to be better prepared for a future stress incident. However, the molecular basis of this is poorly understood. Here, we report the involvement of chromatin modifications in the maintenance of acquired thermotolerance (heat stress [HS] memory). HS memory is associated with the accumulation of histone H3 lysine 4 di- and trimethylation at memory-related loci. This accumulation outlasts their transcriptional activity and marks them as recently transcriptionally active. High accumulation of H3K4 methylation is associated with hyper-induction of gene expression upon a recurring HS. This transcriptional memory and the sustained accumulation of H3K4 methylation depend on HSFA2, a transcription factor that is required for HS memory, but not initial heat responses. Interestingly, HSFA2 associates with memory-related loci transiently during the early stages following HS. In summary, we show that transcriptional memory after HS is associated with sustained H3K4 hyper-methylation and depends on a hit-and-run transcription factor, thus providing a molecular framework for HS memory.

Identification and de novo sequencing of housekeeping genes appropriate for gene expression analyses in farmed maraena whitefish (Coregonus maraena) during crowding stress.

Maraena whitefish (Coregonus maraena; synonym Coregonus lavaretus f. balticus) is a high-quality food fish in the Southern Baltic Sea belonging to the group of salmonid fishes. Coregonus sp. is successfully kept in aquaculture throughout northern Europe (e.g. in Finland, Germany, Russia) and North America. In this regard, the molecular and immunological characterisation of stress response in maraena whitefish contributes to the development of robust and fast-growing maraena whitefish breeding strains for aquaculture. Thus, in the present study, the potential housekeeping genes beta actin (ACTB), elongation factor 1 alpha (EEF1A1), glyceraldehydes-3-phosphate dehydrogenase (GAPDH), ribosomal protein 9 (RPL9), ribosomal protein 32 (RPL32) and ribosomal protein S20 (RPS20) were de novo sequenced and tested concerning their applicability as reference genes in quantitative real-time PCR (qPCR) in maraena whitefish under different stocking densities. For this purpose, tissue samples of liver, kidney, gills, head kidney, skin, adipose tissue, heart and dorsal fin were investigated. qPCR data were analysed with Normfinder tool to determine gene expression stability. DNA sequencing exposed transcribed paralogous EEF1A1A and EEF1A1B genes differing in their putative protein structure. Normfinder analysis revealed RPL9 and RPL32 as most stable, GAPDH and ACTB as least stable genes for qPCR analyses, respectively. This is the first study that provides a subset of seven de novo sequenced housekeeping genes usable as reference genes in studies of stress response in maraena whitefish.

The ABC transporter ABCG1 is required for suberin formation in potato tuber periderm.

The lipid biopolymer suberin plays a major role as a barrier both at plant-environment interfaces and in internal tissues, restricting water and nutrient transport. In potato (Solanum tuberosum), tuber integrity is dependent on suberized periderm. Using microarray analyses, we identified ABCG1, encoding an ABC transporter, as a gene responsive to the pathogen-associated molecular pattern Pep-13. Further analyses revealed that ABCG1 is expressed in roots and tuber periderm, as well as in wounded leaves. Transgenic ABCG1-RNAi potato plants with downregulated expression of ABCG1 display major alterations in both root and tuber morphology, whereas the aerial part of the ABCG1-RNAi plants appear normal. The tuber periderm and root exodermis show reduced suberin staining and disorganized cell layers. Metabolite analyses revealed reduction of esterified suberin components and hyperaccumulation of putative suberin precursors in the tuber periderm of RNA interference plants, suggesting that ABCG1 is required for the export of suberin components.

Arabidopsis miR156 Regulates Tolerance to Recurring Environmental Stress through SPL Transcription Factors.

Plants are sessile organisms that gauge stressful conditions to ensure survival and reproductive success. While plants in nature often encounter chronic or recurring stressful conditions, the strategies to cope with those are poorly understood. Here, we demonstrate the involvement of ARGONAUTE1 and the microRNA pathway in the adaptation to recurring heat stress (HS memory) at the physiological and molecular level. We show that miR156 isoforms are highly induced after HS and are functionally important for HS memory. miR156 promotes sustained expression of HS-responsive genes and is critical only after HS, demonstrating that the effects of modulating miR156 on HS memory do not reflect preexisting developmental alterations. miR156 targets SPL transcription factor genes that are master regulators of developmental transitions. SPL genes are posttranscriptionally downregulated by miR156 after HS, and this is critical for HS memory. Altogether, the miR156-SPL module mediates the response to recurring HS in Arabidopsis thaliana and thus may serve to integrate stress responses with development.

Dietary protein restriction and excess of pregnant German Landrace sows induce changes in hepatic gene expression and promoter methylation of key metabolic genes in the offspring.

Maternal nutrition during gestation has important effects on offspring gene expression mediated by DNA methylation. In order to evaluate the effect of restricted and excess protein intake during gestation, hepatic gene expression and DNA methylation of key metabolic genes NR3C1, PPARα, HMGCR, PGC1α, INSR and CYP2C34 were investigated. Liver samples of German Landrace offspring were collected at Gestational Day 95, at birth, at weaning and from finisher pigs. Gene expression in foetal liver revealed significant differences between the control group (CO) and the low-protein group (LP) in HMGCR (P<.0001), INSR (P=.0003), NR3C1 (P=.020) and PGC1α (P=.003). At birth INSR (P=.032), PPARα (P=.0006) and CYP2C34 (P<.0001) showed significant differences between LP and CO. CYP2C34 was significantly increased in the high-protein group (HP) compared to CO (P=.001). At weaning, INSR was significantly higher expressed in LP than in CO (P=.018). HMGCR showed a significant decrease of transcript amount in HP compared to CO (P=.0006). Furthermore, we studied the question whether gene expression differences between distinct diet groups are a result of differential DNA methylation status. CpG sites in the 5'-flanking region of CYP2C34 showed a significant positive correlation with transcript amount in LP (nt -137: R=0.67, P<.0001; nt -112: R=0.54, P=.003). In NR3C1 methylation, differences in the CpG island were negatively correlated with gene expression data in LP (R=-0.34, P=.032). The mean of methylation of PPARα over CpG sites from nt -220 to -11 was significantly increased in the LP group compared with CO (P=.043). These data suggest an influence of DNA methylation in nutrient-dependent transcriptional regulation of NR3C1, PPARα and CYP2C34.

Maternal dietary protein restriction and excess affects offspring gene expression and methylation of non-SMC subunits of condensin I in liver and skeletal muscle.

Recent evidence indicates that maternal nutrition during pregnancy influences gene expression in offspring through epigenetic alterations. In the present study we evaluated the effect of protein excess and deficiency during porcine pregnancy on offspring hepatic and skeletal muscular expression patterns of key genes of methionine metabolism (DNMT1, DNMT3a, DNMT3b, BHMT, MAT2B and AHCYL1), condensin I subunit genes (NCAPD2, NCAPG and NCAPH), important for chromosome condensation and segregation, global DNA methylation and gene-specific DNA methylation. German Landrace sows were randomly assigned to control (CO), high protein (HP) and low protein (LP) diet groups. Tissue samples of offspring were collected from fetal (dpc95), newborn (dpn1), weanling (dpn28) and finisher pigs (dpn188). Gene expression of DNMT1, DNMT3a and DNMT3b was influenced by both HP and LP diets, indicating an involvement of DNA methylation in fetal programming by maternal protein supply. Moreover, hepatic global methylation was significantly affected by protein restriction at dpc95 (p = 0.004) and by protein excess at dpn188 (p = 0.034). Gene expression in fetal liver was significantly different between CO and LP for NCAPD2 (p = 0.0005), NCAPG (p = 0.0009) and NCAPH (p < 0.0001). In skeletal muscle, LP fetuses had significantly altered gene expression of NCAPD2 (p = 0.020) and NCAPH (p = 0.001), compared with CO. Furthermore, NCAPG was differentially methylated among LP, HP and CO; indeed, a significant positive correlation was detected with transcript amount in fetal pigs (r = 0.47, p = 0.002). These data demonstrate that both restriction and excess dietary protein during pregnancy alters the offspring's epigenetic marks and influences gene expression.

Effect of gestational protein deficiency and excess on hepatic expression of genes related to cell cycle and proliferation in offspring from late gestation to finishing phase in pig.

Maternal diet during gestation is known to affect offspring phenotype induction. In the present study the influence of maternal protein restriction and excess during gestation on offspring candidate gene expression was analysed. German Landrace gilts were fed control, low protein (LP) or high protein (HP) diet throughout gestation (n = 18 per diet group). After birth piglets were cross-fostered and lactated by control diet fed nursing sows. Samples of offspring liver tissue were taken at foetal, newborn, weaning and finishing phase (n = 16, respectively). Transcript amount of selected candidate genes related to cell cycle and cell proliferation was estimated by quantitative real-time PCR. Maternal protein restriction influenced gene expression of candidate genes CCND2, GADD45B, GALK1, GSTP1, MARCKS, MGMT, NEAT1, PSEN1, SNX1 and TRPM7 in liver from foetuses, newborn piglets, weaned and/or finisher pigs. In the offspring of mothers fed a HP diet expression of target genes was affected exclusively in finisher pigs showing increased transcript amount of CCND2, GALK1, MARCKS, SNX1 and TRPM7. The results of the present study clearly show a long-lasting impact of the maternal protein supply during gestation on offspring candidate genes. Remarkably, effects of gestational HP diet became evident in finisher pigs while LP supply already alters genes expression in foetal tissue. Thus it is suggested that LP and HP supply affect the offspring in utero by different physiological mechanisms with the consequence of late effects in case of prenatal protein excess in contrast to early effects in case of protein restriction.

Everolimus in combination with cyclosporin a as pre- and posttransplantation immunosuppressive therapy in nonmyeloablative allogeneic hematopoietic stem cell transplantation.

Everolimus (RAD001) is an mTOR inhibitor that has been successfully used as an immunosuppressant in solid-organ transplantation. Data in allogeneic hematopoietic stem cell transplantation (HSCT) is limited. This study aimed to investigate pharmacokinetics, safety, and efficacy of RAD001 in a canine allogeneic HSCT model. First, pharmacokinetics of RAD001 were performed in healthy dogs in order to determine the appropriate dosing. Doses of 0.25 mg RAD001 twice daily in combination with 15 mg/kg cyclosporin A (CsA) twice daily were identified as appropriate starting doses to achieve the targeted range of RAD001 (3-8 µg/L) when orally administered. Subsequently, 10 dogs were transplanted using 2 Gy total body irradiation (TBI) for conditioning and 0.25 mg RAD001 twice daily plus 15 mg/kg CsA twice daily for pre- and posttransplantation immunosuppression. Seven of the 10 transplanted dogs were maintained at the starting RAD001 dose throughout the study. For the remaining 3 dogs, dose adjustments were necessary. RAD001 accumulation over time did not occur. All dogs initially engrafted. Five dogs eventually rejected the graft (weeks 10, 10, 13, 27, and 56). Two dogs died of pneumonia (weeks 8 and 72) but were chimeric until then. Total cholesterol rose from median 4.1 mmol/L (3.5-5.7 mmol/L) before HSCT to 6.0 mmol/l (5.0-8.5 mmol/l) at day 21 after HSCT, but remained always within normal range. Changes in creatinine and triglyceride values were not observed. Long-term engraftment rates were inferior to sirolimus/CsA and mycophenolate mofetil (MMF)/CsA regimen, respectively. RAD001/CsA caused a more pronounced reduction of platelet counts to median 2 × 10(9)/L (range: 0-21 × 10(9)/L) and longer time to platelet recovery of 21 days (range: 14-24 days) compared with MMF/CsA. CsA c(2h) levels were significantly enhanced in the RAD001/CsA regimen, but c(0h) and area under the curve from 0 to 12 hours (AUC(0-12h)) values did not differ compared with an MMF/CsA immunosuppression. In summary, immunosuppression consisting of RAD001 and CsA is well tolerated but not as efficient as with other established immunosuppressants in a canine nonmyeloablative HSCT regimen. Hence, our study does not support the application of RAD001/CsA as standard practice in this setting.

Upfront denileukin diftitox as in vivo regulatory T-cell depletion in order to enhance vaccination effects in a canine allogeneic hematopoietic stem cell transplantation model.

Denileukin Diftitox (ONTAK(®), DAB(389) IL-2) is a recombinant DNA-derived fusion protein depleting cells that express high-affinity IL-2 receptor. Important cell targets are CD4(+)CD25(+)Foxp3(+) regulatory T cells (T(reg)). Elimination of immunosuppressive T(reg) by Denileukin Diftitox may provide a way to modulate immune tolerance following stem cell transplantation. Here, we combined T(reg) depletion with a vaccination approach to induce donor-specific immune reactions. To investigate this approach we chose the mixed chimerism canine stem cell transplantation model which represents a high state of tolerance between two hematopoietic systems. The aim was therefore to induce a graft versus hematopoiesis effect thereby converting mixed to full donor chimerism. Dog leukocyte antigen identical siblings that had developed a stable mixed chimerism after non-myeloablative stem cell transplantation received a single dose of Denileukin Diftitox (18µg/kg, i.v.) followed by several cell-lysate vaccinations. Host peripheral blood mononuclear cell lysates combined with CpG-ODN, and Montanide(®) ISA 51 were locally applied. In vitro studies demonstrated that canine T(reg) are a target of Denileukin Diftitox. The suppression of T-cell proliferation by T(reg) was abolished by addition of Denileukin Diftitox (10nM). An increase of proliferation of median 300% (range: 200%-425%) was observed. No change in donor chimerism was observed after administration of Denileukin Diftitox and vaccination. This study highlights that application of Denileukin Diftitox resulted in a depletion of T(reg) followed by an increase of immune response in vitro. This effect could not be confirmed in vivo even if the immune system was stimulated by vaccinations.

Somatic cytochrome c (CYCS) gene expression and promoter-specific DNA methylation in a porcine model of prenatal exposure to maternal dietary protein excess and restriction.

There is growing evidence that maternal nutrition during gestation has an important effect on offspring development as well as on their gene expression with long-term effects on the metabolic state. A potential mechanism forming long-lasting gene expression patterns is DNA methylation of cytosine in CpG dinucleotides within the promoter region of distinct genes. There has been special focus on mitochondrial dysfunction by prenatal malnourishment over the recent years. To this end, we investigated the gene expression of somatic cytochrome c (CYCS), an important member of the respiratory chain, in a porcine model of gestational protein over- and undersupply at 94 d post-conception and 1, 28 and 188 d of age, and analysed the association with the DNA methylation status within the CYCS promoter. Gene expression on day 1 post natum showed a significant increase in the low protein (LP) group (P = 0·0005) and a slight increase in the high protein (HP) group (P = 0·079) compared with the control (CO) group in the liver. The mean of the methylation level over forty-seven CpG sites from nucleotide (nt) - 417 to - 10 was significantly decreased in the LP (P = 0·007) and HP (P = 0·009) groups compared with that in the CO group. Excess and restricted protein supply during pregnancy led to hypomethylation of a number of CpG sites in the CYCS promoter, including those representing putative transcription factor-binding sites, associated with elevated expression levels. However, the impact of the low-protein gestation diet is more pronounced, indicating that the offspring could better adapt to excess rather than restricted protein supply.