Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery.

BACKGROUND: Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother-offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD. RESULTS: The higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup's immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups' microbiota. CONCLUSIONS: Early-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice. Video Abstract.

Country-level fire perimeter datasets (2001-2021).

Fire activity is changing across many areas of the globe. Understanding how social and ecological systems respond to fire is an important topic for the coming century. But many countries do not have accessible fire history data. There are several satellite-based products available as gridded data, but these can be difficult to access and use, and require significant computational resources and time to convert into a usable product for a specific area of interest. We developed an open source software package called Fire Event Delineation for python (FIREDpy) which automatically downloads and processes all of the source files for an area of interest from the MODIS burned area product, and runs a spatiotemporal flooding algorithm that converts those hundreds of grids into a single fire perimeter shapefile. Here we present a collection of fire event perimeter datasets for every country on the globe that we created using the FIREDpy software. We will continue to improve the efficiency and flexibility of the underlying algorithm, and intend to update these datasets annually.

In vivo delivery of plasmid DNA by lipid nanoparticles: the influence of ionizable cationic lipids on organ-selective gene expression.

Ionizable cationic lipids play a critical role in developing new gene therapies for various biomedical applications, including COVID-19 vaccines. However, it remains unclear whether the formulation of lipid nanoparticles (LNPs) using DLin-MC3-DMA, an optimized ionizable lipid clinically used for small interfering RNA (siRNA) therapy, also facilitates high liver-selective transfection of other gene therapies such as plasmid DNA (pDNA). Here we report the first investigation into pDNA transfection efficiency in different mouse organs after intramuscular and intravenous administration of lipid nanoparticles (LNPs) where DLin-MC3-DMA, DLin-KC2-DMA or DODAP are used as the ionizable cationic lipid component of the LNP. We discovered that these three benchmark lipids previously developed for siRNA delivery followed an unexpected characteristic rank order in gene expression efficiency when utilized for pDNA. In particular, DLin-KC2-DMA facilitated higher in vivo pDNA transfection than DLin-MC3-DMA and DODAP, possibly due to its head group pKa and lipid tail structure. Interestingly, LNPs formulated with either DLin-KC2-DMA or DLin-MC3-DMA exhibited significantly higher in vivo protein production in the spleen than in the liver. This work sheds light on the importance of the choice of ionizable cationic lipid and nucleic acid cargo for organ-selective gene expression. The study also provides a new design principle towards the formulation of more effective LNPs for biomedical applications of pDNA, such as gene editing, vaccines and immunotherapies.

Quantifying spatial non-stationarity in the relationship between landscape structure and the provision of ecosystem services: An example in the New Zealand hill country.

Knowing how landscape structure affects the provision of ecosystem services (ES) is an important first step toward better landscape planning. Because landscape structure is often heterogenous across space, modelling the relationship between landscape structure and the provision of ES must account for spatial non-stationarity. This paper examines the relationship between landscape structure and the provision of ES using a hill country and steep-land case farm in New Zealand. Indicators derived from land cover and topographical data such as Largest Patch Index (LPI), Contrast Class Edge (CCE), Edge Density (ED), and Terrain slope (SLOPE) were used to examine the landscape's structure and pattern. Measures of pasture productivity, soil erosion control, and water supply were derived with InVEST tools and spatial analysis in a GIS. Multiscale Geographically Weighted Regression (MGWR) was used to evaluate the relationship between indicators of landscape structure and the provisioning of ES. Other regression models, including Ordinary Least Square (OLS) and Geographically Weighted Regression (GWR), were carried out to evaluate the performance of MGWR. Results showed that landscape patterns significantly affect the supply of all mapped ES, and this varies across the landscape, dependent on the pattern of topographical features and land cover pattern and structure. MWGR outperformed other OLS and GWR in terms of explanatory power of the ES determinants and had a better ability to deal with the presence of spatial autocorrelation. Spatially and quantitatively detailed variations of the relationship between landscape structure and the provision of ES provide a scientific basis to inform the design of sustainable multifunctional landscapes. Information derived from this analysis can be used for spatial planning of farmed landscapes to promote multiple ES which meet multiple sustainable development objectives.

Super-Cationic Peptide Dendrimers-Synthesis and Evaluation as Antimicrobial Agents.

Microbial infections are a major public health concern. Antimicrobial peptides (AMPs) have been demonstrated to be a plausible alternative to the current arsenal of drugs that has become inefficient due to multidrug resistance. Herein we describe a new AMP family, namely the super-cationic peptide dendrimers (SCPDs). Although all members of the series exert some antibacterial activity, we propose that special attention should be given to (KLK)2KLLKLL-NH2 (G1KLK-L2KL2), which shows selectivity for Gram-negative bacteria and virtually no cytotoxicity in HepG2 and HEK293. These results reinforce the validity of the SCPD family as a valuable class of AMP and support G1KLK-L2KL2 as a strong lead candidate for the future development of an antibacterial agent against Gram-negative bacteria.

From influenza to COVID-19: Lipid nanoparticle mRNA vaccines at the frontiers of infectious diseases.

Vaccination represents the best line of defense against infectious diseases and is crucial in curtailing pandemic spread of emerging pathogens to which a population has limited immunity. In recent years, mRNA vaccines have been proposed as the new frontier in vaccination, owing to their facile and rapid development while providing a safer alternative to traditional vaccine technologies such as live or attenuated viruses. Recent breakthroughs in mRNA vaccination have been through formulation with lipid nanoparticles (LNPs), which provide both protection and enhanced delivery of mRNA vaccines in vivo. In this review, current paradigms and state-of-the-art in mRNA-LNP vaccine development are explored through first highlighting advantages posed by mRNA vaccines, establishing LNPs as a biocompatible delivery system, and finally exploring the use of mRNA-LNP vaccines in vivo against infectious disease towards translation to the clinic. Furthermore, we highlight the progress of mRNA-LNP vaccine candidates against COVID-19 currently in clinical trials, with the current status and approval timelines, before discussing their future outlook and challenges that need to be overcome towards establishing mRNA-LNPs as next-generation vaccines. STATEMENT OF SIGNIFICANCE: With the recent success of mRNA vaccines developed by Moderna and BioNTech/Pfizer against COVID-19, mRNA technology and lipid nanoparticles (LNP) have never received more attention. This manuscript timely reviews the most advanced mRNA-LNP vaccines that have just been approved for emergency use and are in clinical trials, with a focus on the remarkable development of several COVID-19 vaccines, faster than any other vaccine in history. We aim to give a comprehensive introduction of mRNA and LNP technology to the field of biomaterials science and increase accessibility to readers with a new interest in mRNA-LNP vaccines. We also highlight current limitations and future outlook of the mRNA vaccine technology that need further efforts of biomaterials scientists to address.

Lipid-Based Nanoparticles in the Clinic and Clinical Trials: From Cancer Nanomedicine to COVID-19 Vaccines.

COVID-19 vaccines have been developed with unprecedented speed which would not have been possible without decades of fundamental research on delivery nanotechnology. Lipid-based nanoparticles have played a pivotal role in the successes of COVID-19 vaccines and many other nanomedicines, such as Doxil® and Onpattro®, and have therefore been considered as the frontrunner in nanoscale drug delivery systems. In this review, we aim to highlight the progress in the development of these lipid nanoparticles for various applications, ranging from cancer nanomedicines to COVID-19 vaccines. The lipid-based nanoparticles discussed in this review are liposomes, niosomes, transfersomes, solid lipid nanoparticles, and nanostructured lipid carriers. We particularly focus on the innovations that have obtained regulatory approval or that are in clinical trials. We also discuss the physicochemical properties required for specific applications, highlight the differences in requirements for the delivery of different cargos, and introduce current challenges that need further development. This review serves as a useful guideline for designing new lipid nanoparticles for both preventative and therapeutic vaccines including immunotherapies.

Digestion of Lipid-Based Formulations Not Only Mediates Changes to Absorption of Poorly Soluble Drugs Due to Differences in Solubilization But Also Reflects Changes to Thermodynamic Activity and Permeability.

The aim of this study was to evaluate the effect of lipid digestion on the permeability and absorption of orally administered saquinavir (SQV), a biopharmaceutics classification system (BCS) class IV drug, in different lipid-based formulations. Three LBFs were prepared: a mixed short- and medium-chain lipid-based formulation (SMCF), a medium-chain lipid-based formulation (MCF), and a long-chain lipid-based formulation (LCF). SQV was loaded into these LBFs at 26.7 mg/g. To evaluate the pharmacokinetics of SQV in vivo, drug-loaded formulations were predispersed in purified water at 3% w/w and orally administered to rats. A low dose (0.8 mg/rat) was employed to limit confounding effects on drug solubilization, and consistent with this design, presolubilization of SQV in the LBFs did not increase in vivo exposure compared to a control suspension formulation. The areas under the plasma concentration-time curve were, however, significantly lower after administration of SQV as MCF and LCF compared to SMCF. To evaluate the key mechanisms underpinning absorption, each LBF containing SQV was digested, and the flux of SQV from the digests across a dialysis membrane was evaluated in in vitro permeation experiments. This study revealed that the absorption profiles were driven by the free concentration of SQV and that this varied due to differences in SQV solubilization in the digestion products generated by LBF digestion. The apparent first-order permeation rate constants of SQV (kapp,total) were estimated by dividing the flux of SQV in the dialysis membrane experiments by the concentration of total SQV on the donor side. kapp,total values strongly correlated with in vivo AUC. The data provide one of the first studies of the effect of digestion products on the free concentration of a drug in the GI fluid and oral absorption. This simple permeation model may be a useful tool for the evaluation of the impact of lipid digestion on apparent drug permeability from lipid-based formulations. These effects should be assessed alongside, and in addition to, the more well-known effects of lipids on enhancing intestinal solubilization of poorly water-soluble drugs.

Interaction with biliary and pancreatic fluids drives supersaturation and drug absorption from lipid-based formulations of low (saquinavir) and high (fenofibrate) permeability poorly soluble drugs.

Drug absorption from lipid-based formulations (LBFs) in the gastrointestinal (GI) tract is the result of a series of processes, including formulation dispersion, interaction with biliary and pancreatic secretions, drug solubilisation and supersaturation, and finally intestinal permeability. Optimal formulation design is dependent on a good understanding of the limitations to, and drivers of, absorption, but for LBFs the complexity of these processes makes data interpretation complex. The current study has re-examined a previous in vitro digestion-in situ perfusion model to increase physiological relevance and has used this model to examine drug absorption from LBFs. The composition of rat bile and jejunal fluid was also characterised to identify in vivo-relevant conditions. Digestion was initiated using rat bile/pancreatic fluid and the formulation and digestive enzymes mixed immediately prior to entry into the jejunum (allowing dilution/digestion to occur at the absorptive site). These conditions were employed to study drug absorption from LBFs of high (fenofibrate, FFB) and low (saquinavir, SQV) permeability compounds. The impact of polymeric precipitation inhibitors (PPIs) was also evaluated. For FFB, supersaturation, initiated by formulation interaction with biliary/pancreatic fluids, appeared to drive absorption and the addition of the PPIs poly(glycidyl methacrylate) (PPGAE) and hydroxypropylmethyl cellulose (HPMC), reduced drug precipitation, increased FFB supersaturation and increased absorption from a Type IV LBF of FFB. For a Type IIIB LBF however, PPIs were ineffective at increasing absorption. The impact of PPIs on the absorption of a less permeable drug, SQV, was similarly evaluated and again drug absorption appeared to be related to the extent of supersaturation, although in this case PPI were unable to promote absorption. For both FFB and SQV, drug absorption patterns obtained with the in vitro digestion-in situ perfusion mode, correlated well with in vitro supersaturation data and in vivo drug exposure data from oral bioavailability studies. The data are consistent with a mode of drug absorption where rapid dilution of LBFs with biliary and pancreatic secretions at the absorptive site in the upper small intestine drives transient supersaturation, that supersaturation is a significant driver of drug absorption for both low and high permeability drugs, and that PPIs delay drug precipitation, enhance supersaturation and promote drug absorption in a drug and formulation specific manner.

The Importance of Poly(ethylene glycol) and Lipid Structure in Targeted Gene Delivery to Lymph Nodes by Lipid Nanoparticles.

Targeted delivery of nucleic acids to lymph nodes is critical for the development of effective vaccines and immunotherapies. However, it remains challenging to achieve selective lymph node delivery. Current gene delivery systems target mainly to the liver and typically exhibit off-target transfection at various tissues. Here we report novel lipid nanoparticles (LNPs) that can deliver plasmid DNA (pDNA) to a draining lymph node, thereby significantly enhancing transfection at this target organ, and substantially reducing gene expression at the intramuscular injection site (muscle). In particular, we discovered that LNPs stabilized by 3% Tween 20, a surfactant with a branched poly(ethylene glycol) (PEG) chain linking to a short lipid tail, achieved highly specific transfection at the lymph node. This was in contrast to conventional LNPs stabilized with a linear PEG chain and two saturated lipid tails (PEG-DSPE) that predominately transfected at the injection site (muscle). Interestingly, replacing Tween 20 with Tween 80, which has a longer unsaturated lipid tail, led to a much lower transfection efficiency. Our work demonstrates the importance of PEGylation in selective organ targeting of nanoparticles, provides new insights into the structure-property relationship of LNPs, and offers a novel, simple, and practical PEGylation technology to prepare the next generation of safe and effective vaccines against viruses or tumours.

Transcription from a gene desert in a melanoma porcine model.

The genetic mechanisms underlying cutaneous melanoma onset and progression need to be further understood to improve patients' care. Several studies have focused on the genetic determinism of melanoma development in the MeLiM pig, a biomedical model of cutaneous melanoma. The objective of this study was to better describe the influence of a particular genomic region on melanoma progression in the MeliM model. Indeed, a large region of the Sus scrofa chromosome 1 has been identified by linkage and association analyses, but the causal mechanisms have remained elusive. To deepen the analysis of this candidate region, a dedicated SNP panel was used to fine map the locus, downsizing the interval to less than 2 Mb, in a genomic region located within a large gene desert. Transcription from this locus was addressed using a tiling array strategy and further validated by RT-PCR in a large panel of tissues. Overall, the gene desert showed an extensive transcriptional landscape, notably dominated by repeated element transcription in tumor and fetal tissues. The transcription of LINE-1 and PERVs has been confirmed in skin and tumor samples from MeLiM pigs. In conclusion, although this study still does not identify a candidate mutation for melanoma occurrence or progression, it highlights a potential role of repeated element transcriptional activity in the MeLiM model.

Genomic diversity, linkage disequilibrium and selection signatures in European local pig breeds assessed with a high density SNP chip.

Genetic characterization of local breeds is essential to preserve their genomic variability, to advance conservation policies and to contribute to their promotion and sustainability. Genomic diversity of twenty European local pig breeds and a small sample of Spanish wild pigs was assessed using high density SNP chips. A total of 992 DNA samples were analyzed with the GeneSeek Genomic Profiler (GGP) 70 K HD porcine genotyping chip. Genotype data was employed to compute genetic diversity, population differentiation and structure, genetic distances, linkage disequilibrium and effective population size. Our results point out several breeds, such as Turopolje, Apulo Calabrese, Casertana, Mora Romagnola and Lithuanian indigenous wattle, having the lowest genetic diversity, supported by low heterozygosity and very small effective population size, demonstrating the need of enhanced conservation strategies. Principal components analysis showed the clustering of the individuals of the same breed, with few breeds being clearly isolated from the rest. Several breeds were partially overlapped, suggesting genetic closeness, which was particularly marked in the case of Iberian and Alentejana breeds. Spanish wild boar was also narrowly related to other western populations, in agreement with recurrent admixture between wild and domestic animals. We also searched across the genome for loci under diversifying selection based on FST outlier tests. Candidate genes that may underlie differences in adaptation to specific environments and productive systems and phenotypic traits were detected in potentially selected genomic regions.

Towards the quantitative characterisation of piglets' robustness to weaning: a modelling approach.

Weaning is a critical transition phase in swine production in which piglets must cope with different stressors that may affect their health. During this period, the prophylactic use of antibiotics is still frequent to limit piglet morbidity, which raises both economic and public health concerns such as the appearance of antimicrobial-resistant microbes. With the interest of developing tools for assisting health and management decisions around weaning, it is key to provide robustness indexes that inform on the animals' capacity to endure the challenges associated with weaning. This work aimed at developing a modelling approach for facilitating the quantification of piglet resilience to weaning. A total of 325 Large White pigs weaned at 28 days of age were monitored and further housed and fed conventionally during the post-weaning period without antibiotic administration. Body weight and diarrhoea scores were recorded before and after weaning, and blood was sampled at weaning and 1 week later for collecting haematological data. A dynamic model was constructed based on the Gompertz-Makeham law to describe live weight trajectories during the first 75 days after weaning, following the rationale that the animal response is partitioned in two time windows (a perturbation and a recovery window). Model calibration was performed for each animal. Our results show that the transition time between the two time windows, as well as the weight trajectories are characteristic for each individual. The model captured the weight dynamics of animals at different degrees of perturbation, with an average coefficient of determination of 0.99, and a concordance correlation coefficient of 0.99. The utility of the model is that it provides biologically meaningful parameters that inform on the amplitude and length of perturbation, and the rate of animal recovery. Our rationale is that the dynamics of weight inform on the capability of the animal to cope with the weaning disturbance. Indeed, there were significant correlations between model parameters and individual diarrhoea scores and haematological traits. Overall, the parameters of our model can be useful for constructing weaning robustness indexes by using exclusively the growth curves. We foresee that this modelling approach will provide a step forward in the quantitative characterisation of robustness.

Farming in a changing environment: Increasing biodiversity on farm for the supply of multiple ecosystem services.

Among natural resources, soils continue to be poorly represented in ecosystem services frameworks and decision-making processes. Similarly, the supply of multiple ecosystem services from agro-ecosystems and trade-offs between services remains under-researched. As a consequence, it is unclear how and to what extent agriculture can deliver on environmental sustainability, whilst maintaining current levels of profitability. One of the main barriers to implementation of environmental management practices is the perception by the farming industry that environmental gains come at a cost and impact negatively on profitability. Therefore, we need to demonstrate that inclusion of all the natural resources on farm in farm system design and management offers flexibility for the farm system and insures improved sustainability and greater resilience. In this study, an ecosystem approach was paired with a new generation farm system optimisation model and the inclusion of natural resources beyond land, especially biodiversity, to explore farm system design, and report on ecosystem services beyond food and fibre from different parts of the farm. The approach was tested on a sheep and beef farm in Waikato, New Zealand to explore the added benefits of replanting fragile parts of the farm landscape for soil and biodiversity enhancement on reduced emissions to air and water, and trade-offs between different services and farm profitability. The approach showed that it is possible to define and include ecological boundaries within which resources can be managed to deliver multiple benefits ranging from increased per hectare profitability to decreased environmental footprints. This is a feature analytical farm system frameworks will require in the future. The research also highlighted the importance of developing our understanding of the relationship between the condition and function of indigenous biodiversity fragments and adjacent pastoral ecosystems and their contribution to economic, environmental, cultural and social outcomes on and beyond the farm.

A Nonionic Polyethylene Oxide (PEO) Surfactant Model: Experimental and Molecular Dynamics Studies of Kolliphor EL.

Polyethoxylated, nonionic surfactants are important constituents of many drug formulations, including lipid-based formulations. In an effort to better understand the behavior of formulation excipients at the molecular level, we have developed molecular dynamics (MD) models for the widely used surfactant Kolliphor EL (KOL), a triricinoleate ester of ethoxylated glycerol. In this work, we have developed models based on a single, representative molecular component modeled with 2 force field variations based on the GROMOS 53A6DBW and 2016H66 force field parameters for polyethoxylate chains. To compare the computational models to experimental measurements, we investigated the phase behavior of KOL using nephelometry, dynamic light scattering, cross-polarized microscopy, small-angle X-ray scattering, and cryogenic transmission electron microscopy. The potential for digestion of KOL was also evaluated using an in vitro digestion experiment. We found that the size and spherical morphology of the KOL colloids at low concentrations was reproduced by the MD models as well as the growing interactions between the aggregates to from rod-like structures at high concentrations. We believe that this model reproduces the phase behavior of KOL relevant to drug absorption and that it can be used in whole formulation simulations to accelerate the formulation development.

In Vitro Antibacterial Activity of Teixobactin Derivatives on Clinically Relevant Bacterial Isolates.

Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) are included on the WHO high priority list of pathogens that require urgent intervention. Hence emphasis needs to be placed on developing novel class of molecules to tackle these pathogens. Teixobactin is a new class of antibiotic that has demonstrated antimicrobial activity against common bacteria. Here we examined the antimicrobial properties of three Teixobactin derivatives against clinically relevant bacterial isolates taken from South African patients. The minimum inhibitory concentration (MIC), the minimal bactericidal concentration (MBC), the effect of serum on MICs and the time-kill kinetics studies of our synthesized Teixobactin derivatives (3, 4, and 5) were ascertained following the CLSI 2017 guidelines and using the broth microdilution method. Haemolysis on red blood cells (RBCs) and cytotoxicity on peripheral blood mononuclear cells (PBMCs) were performed to determine the safety of these compounds. The MICs of 3, 4, and 5 against reference strains were 4-64 µg/ml, 2-64 µg/ml, and 0.5-64 µg/ml, respectively. The MICs observed for MRSA were (3) 32 µg/ml, (4) 2-4 µg/ml and (5) 2-4 µg/ml whilst those for VRE were (3) 8-16 µg/ml, (4) 4 µg/ml and (5) 2-16 µg/ml, respectively. In the presence of 50% human serum, there was no significant effect on the MICs. The compounds did not exhibit any effect on cell viability at their effective concentrations. Teixobactin derivatives (3, 4, and 5) inhibited bacterial growth in drug-resistant bacteria and hence emerge as potential antimicrobial agents. Molecular dynamic simulations suggested that the most dominant binding mode of Lys10-teixobactin (4) to lipid II is through the amide protons of the cycle, which is identical to data described in the literature for the natural teixobactin hence predicting the possibility of a similar mechanism of action.

Immunome differences between porcine ileal and jejunal Peyer's patches revealed by global transcriptome sequencing of gut-associated lymphoid tissues.

The epithelium of the intestinal mucosa and the gut-associated lymphoid tissues (GALT) constitute an essential physical and immunological barrier against pathogens. In order to study the specificities of the GALT transcriptome in pigs, we compared the transcriptome profiles of jejunal and ileal Peyer's patches (PPs), mesenteric lymph nodes (MLNs) and peripheral blood (PB) of four male piglets by RNA-Seq. We identified 1,103 differentially expressed (DE) genes between ileal PPs (IPPs) and jejunal PPs (JPPs), and six times more DE genes between PPs and MLNs. The master regulator genes FOXP3, GATA3, STAT4, TBX21 and RORC were less expressed in IPPs compared to JPPs, whereas the transcription factor BCL6 was found more expressed in IPPs. In comparison between IPPs and JPPs, our analyses revealed predominant differential expression related to the differentiation of T cells into Th1, Th2, Th17 and iTreg in JPPs. Our results were consistent with previous reports regarding a higher T/B cells ratio in JPPs compared to IPPs. We found antisense transcription for respectively 24%, 22% and 14% of the transcripts detected in MLNs, PPs and PB, and significant positive correlations between PB and GALT transcriptomes. Allele-specific expression analyses revealed both shared and tissue-specific cis-genetic control of gene expression.

Polymeric Precipitation Inhibitors Promote Fenofibrate Supersaturation and Enhance Drug Absorption from a Type IV Lipid-Based Formulation.

The ability of lipid-based formulations (LBFs) to increase the solubilization, and prolong the supersaturation, of poorly water-soluble drugs (PWSDs) in the gastrointestinal (GI) fluids has generated significant interest in the past decade. One mechanism to enhance the utility of LBFs is to prolong supersaturation via the addition of polymers that inhibit drug precipitation (polymeric precipitation inhibitors or PPIs) to the formulation. In this work, we have evaluated the performance of a range of PPIs and have identified PPIs that are sufficiently soluble in LBF to allow the construction of single phase formulations. An in vitro model was first employed to assess drug (fenofibrate) solubilization and supersaturation on LBF dispersion and digestion. An in vitro-in situ model was subsequently employed to simultaneously evaluate the impact of PPI enhanced drug supersaturation on drug absorption in rats. The stabilizing effect of the polymers was polymer specific and most pronounced at higher drug loads. Polymers that were soluble in LBF allowed simple processing as single phase formulations, while formulations containing more hydrophilic polymers required polymer suspension in the formulation. The lipid-soluble polymers Eudragit (EU) RL100 and poly(propylene glycol) bis(2-aminopropyl ether) (PPGAE) and the water-soluble polymer hydroxypropylmethyl cellulose (HPMC) E4M were identified as the most effective PPIs in delaying fenofibrate precipitation in vitro. An in vitro model of lipid digestion was subsequently coupled directly to an in situ single pass intestinal perfusion assay to evaluate the influence of PPIs on fenofibrate absorption from LBFs in vivo. This coupled model allowed for real-time evaluation of the impact of supersaturation stabilization on absorptive drug flux and provided better discrimination between the different PPIs and formulations. In the presence of the in situ absorption sink, increased fenofibrate supersaturation resulted in increased drug exposure, and a good correlation was found between the degree of in vitro supersaturation and in vivo drug exposure. An improved in vitro-in vivo correlation was apparent when comparing the same formulation under different supersaturation conditions. These observations directly exemplify the potential utility of PPIs in promoting drug absorption from LBF, via stabilization of supersaturation, and further confirm that relatively brief periods of supersaturation may be sufficient to promote drug absorption, at least for highly permeable drugs such as fenofibrate.

Deciphering the genetic regulation of peripheral blood transcriptome in pigs through expression genome-wide association study and allele-specific expression analysis.

BACKGROUND: Efforts to improve sustainability in livestock production systems have focused on two objectives: investigating the genetic control of immune function as it pertains to robustness and disease resistance, and finding predictive markers for use in breeding programs. In this context, the peripheral blood transcriptome represents an important source of biological information about an individual's health and immunological status, and has been proposed for use as an intermediate phenotype to measure immune capacity. The objective of this work was to study the genetic architecture of variation in gene expression in the blood of healthy young pigs using two approaches: an expression genome-wide association study (eGWAS) and allele-specific expression (ASE) analysis. RESULTS: The blood transcriptomes of 60-day-old Large White pigs were analyzed by expression microarrays for eGWAS (242 animals) and by RNA-Seq for ASE analysis (38 animals). Using eGWAS, the expression levels of 1901 genes were found to be associated with expression quantitative trait loci (eQTLs). We recovered 2839 local and 1752 distant associations (Single Nucleotide Polymorphism or SNP located less or more than 1 Mb from expression probe, respectively). ASE analyses confirmed the extensive cis-regulation of gene transcription in blood, and revealed allelic imbalance in 2286 SNPs, which affected 763 genes. eQTLs and ASE-genes were widely distributed on all chromosomes. By analyzing mutually overlapping eGWAS results, we were able to describe putative regulatory networks, which were further refined using ASE data. At the functional level, genes with genetically controlled expression that were detected by eGWAS and/or ASE analyses were significantly enriched in biological processes related to RNA processing and immune function. Indeed, numerous distant and local regulatory relationships were detected within the major histocompatibility complex region on chromosome 7, revealing ASE for most class I and II genes. CONCLUSIONS: This study represents, to the best of our knowledge, the first genome-wide map of the genetic control of gene expression in porcine peripheral blood. These results represent an interesting resource for the identification of genetic markers and blood biomarkers associated with variations in immunity traits in pigs, as well as any other complex traits for which blood is an appropriate surrogate tissue.