Completion of the swine genome will simplify the production of swine as a large animal biomedical model

Generation and transcriptomic characterization of MIR137 knockout miniature pig model for neurodevelopmental disorders

BACKGROUND

Neurodevelopmental disorders (NDD), such as autism spectrum disorders (ASD) and intellectual disorders (ID), are highly debilitating childhood psychiatric conditions. Genetic factors are recognized as playing a major role in NDD, with a multitude of genes and genomic regions implicated. While the functional validation of NDD-associated genes has predominantly been carried out using mouse models, the significant differences in brain structure and gene function between mice and humans have limited the effectiveness of mouse models in exploring the underlying mechanisms of NDD. Therefore, it is important to establish alternative animal models that are more evolutionarily aligned with humans.

RESULTS

In this study, we employed CRISPR/Cas9 and somatic cell nuclear transplantation technologies to successfully generate a knockout miniature pig model of the MIR137 gene, which encodes the neuropsychiatric disorder-associated microRNA miR-137. The homozygous knockout of MIR137 (MIR137-/-) effectively suppressed the expression of mature miR-137 and led to the birth of stillborn or short-lived piglets. Transcriptomic analysis revealed significant changes in genes associated with neurodevelopment and synaptic signaling in the brains of MIR137-/- miniature pig, mirroring findings from human ASD transcriptomic data. In comparison to miR-137-deficient mouse and human induced pluripotent stem cell (hiPSC)-derived neuron models, the miniature pig model exhibited more consistent changes in critical neuronal genes relevant to humans following the loss of miR-137. Furthermore, a comparative analysis identified differentially expressed genes associated with ASD and ID risk genes in both miniature pig and hiPSC-derived neurons. Notably, human-specific miR-137 targets, such as CAMK2A, known to be linked to cognitive impairments and NDD, exhibited dysregulation in MIR137-/- miniature pigs. These findings suggest that the loss of miR-137 in miniature pigs affects genes crucial for neurodevelopment, potentially contributing to the development of NDD.

CONCLUSIONS

Our study highlights the impact of miR-137 loss on critical genes involved in neurodevelopment and related disorders in MIR137-/- miniature pigs. It establishes the miniature pig model as a valuable tool for investigating neurodevelopmental disorders, providing valuable insights for potential applications in human research.

Retinal transplant immunology and advancements

Several gaps and barriers remain for transplanting stem cells into the eye to treat ocular disease, especially diseases of the retina. While the eye has historically been considered immune privileged, recent thinking has identified the immune system as both a barrier and an opportunity for eye stem cell transplantation. Recent approaches leveraging scaffolds or cloaking have been considered in other tissues beyond immune suppression. This perspective paper outlines approaches for transplantation and proposes opportunities to overcome barriers of the immune system in stem cell transplantation in the eye.

Microbiota-sensitive drug delivery systems based on natural polysaccharides for colon targeting

Colon targeting is an ongoing challenge, particularly for the oral administration of biological drugs or local treatment of inflammatory bowel disease (IBD). In both cases, drugs are known to be sensitive to the harsh conditions of the upper gastrointestinal tract (GIT) and, thus, must be protected. Here, we provide an overview of recently developed colonic site-specific drug delivery systems based on microbiota sensitivity of natural polysaccharides. Polysaccharides act as a substrate for enzymes secreted by the microbiota located in the distal part of GIT. The dosage form is adapted to the pathophysiology of the patient and, thus, a combination of bacteria-sensitive and time-controlled release or pH-dependent systems can be used for delivery.

Association Analysis of PRKAA2 and MSMB Polymorphisms and Growth Traits of Xiangsu Hybrid Pigs

In this study, Xiangsu hybrid pig growth traits were evaluated via PRKAA2 and MSMB as candidate genes. Sanger sequencing revealed three mutation sites in PRKAA2, namely, g.42101G>T, g.60146A>T, and g.61455G>A, and all these sites were intronic mutations. Moreover, six mutation sites were identified in MSMB: intronic g.4374G>T, exonic g.4564T>C, exonic g.6378G>A, exonic g.6386C>T, intronic g.8643G>A, and intronic g.8857A>G. Association analysis revealed that g.42101G>T, g.60146A>T, g.61455G>A, g.4374G>T, g.4564T>C, g.6378G>A, g.6386C>T, g.8643G>A, and g.8857A>G showed different relationship patterns among body weight, body length, body height, chest circumference, abdominal circumference, tube circumference, and chest depth. Real-time polymerase chain reaction results revealed that the expression of PRKAA2 was highest in the longissimus dorsi muscle, followed by that in the heart, kidney, liver, lung, and spleen. The expression of MSMB was highest in the spleen, followed by that in the liver, kidney, lung, heart, and longissimus dorsi muscle. These results suggest that PRKAA2 and MSMB can be used in marker-assisted selection to improve growth related traits in Xiangsu hybrid pigs, providing new candidate genes for Pig molecular breeding.

Role of Mucin 2 Glycoprotein and L-Fucose in Interaction of Immunity and Microbiome within the Experimental Model of Inflammatory Bowel Disease

Many factors underlie the development of inflammatory bowel disease (IBD) in humans. In particular, imbalance of microbiota and thinning of the mucosal layer in the large intestine play a huge role. Pathogenic microorganisms also exacerbate the course of diseases. In this research the role of mucin 2 deficiency in the formation of intestinal microflora in the experimental model using the Muc2 gene knockout mice in the presence of Helicobacter spp. was investigated. Also, restorative and anti-inflammatory effect of the dietary L-fucose in the Muc2^-/- mice on microflora and immunity was evaluated. For this purpose, bacterial diversity in feces was studied in the animals before and after antibiotic therapy and role of the dietary L-fucose in their recovery was assessed. To determine the effect of bacterial imbalance and fucose on the immune system, mRNA levels of the genes encoding pro-inflammatory cytokines (Tnf, Il1a, Il1b, Il6) and transcription factors of T cells (Foxp3 - Treg, Rorc - Th17, Tbx21 - Th1) were determined in the colon tissue of the Muc2^-/- mice. Significant elimination of bacteria due to antibiotic therapy caused decrease of the fucose levels in the intestine and facilitated reduction of the regulatory T cell transcription factor (Foxp3). When the dietary L-fucose was added to antibiotics, the level of bacterial DNA of Bacteroides spp. in the feces of the Muc2^-/- mice was partially restored. T regulatory cells are involved in the regulation of inflammation in the Muc2^-/- mice. Antibiotics reduced the number of regulatory T cell but did not decrease the inflammatory response to infection. Fucose, as a component of mucin 2, helped to maintain the level of Bacteroides spp. during antibiotic therapy of the Muc2^-/- mice and restored biochemical parameters, but did not affect the inflammatory response.

Porcine Models of the Intestinal Microbiota: The Translational Key to Understanding How Gut Commensals Contribute to Gastrointestinal Disease

In the United States, gastrointestinal disorders account for in excess of $130 billion in healthcare expenditures and 22 million hospitalizations annually. Many of these disorders, including necrotizing enterocolitis of infants, obesity, diarrhea, and inflammatory bowel disease, are associated with disturbances in the gastrointestinal microbial composition and metabolic activity. To further elucidate the pathogenesis of these disease syndromes as well as uncover novel therapies and preventative measures, gastrointestinal researchers should consider the pig as a powerful, translational model of the gastrointestinal microbiota. This is because pigs and humans share striking similarities in their intestinal microbiota as well as gastrointestinal anatomy and physiology. The introduction of gnotobiotic pigs, particularly human-microbial associated pigs, has already amplified our understanding of many gastrointestinal diseases that have detrimental effects on human health worldwide. Continued utilization of these models will undoubtedly inform translational advancements in future gastrointestinal research and potential therapeutics.

Protective Effects of Natural Polysaccharides on Intestinal Barrier Injury: A Review

Owing to their minimal side effects and effective protection from oxidative stress, inflammation, and malignant growth, natural polysaccharides (NPs) are a potential adjuvant therapy for several diseases caused by intestinal barrier injury (IBI). More studies are accumulating on the protective effects of NPs with respect to IBI, but the underlying mechanisms remain unclear. Thus, this review aims to represent current studies that investigate the protective effects of NPs on IBI by directly maintaining intestinal epithelial barrier integrity (inhibiting oxidative stress, regulating inflammatory cytokine expression, and increasing tight junction protein expression) and indirectly regulating intestinal immunity and microbiota. Furthermore, the mechanisms underlying IBI development are briefly introduced, and the structure-activity relationships of polysaccharides with intestinal barrier protection effects are discussed. Potential developments and challenges associated with NPs exhibiting protective effects against IBI have also been highlighted to guide the application of NPs in the treatment of intestinal diseases caused by IBI.

Hepatic galectin-3 is associated with lipid droplet area in non-alcoholic steatohepatitis in a new swine model

Non-alcoholic fatty liver disease (NAFLD) is currently a growing epidemic disease that can lead to cirrhosis and hepatic cancer when it evolves into non-alcoholic steatohepatitis (NASH), a gap not well understood. To characterize this disease, pigs, considered to be one of the most similar to human experimental animal models, were used. To date, all swine-based settings have been carried out using rare predisposed breeds or long-term experiments. Herein, we fully describe a new experimental swine model for initial and reversible NASH using cross-bred animals fed on a high saturated fat, fructose, cholesterol, cholate, choline and methionine-deficient diet. To gain insight into the hepatic transcriptome that undergoes steatosis and steatohepatitis, we used RNA sequencing. This process significantly up-regulated 976 and down-regulated 209 genes mainly involved in cellular processes. Gene expression changes of 22 selected transcripts were verified by RT-qPCR. Lipid droplet area was positively associated with CD68, GPNMB, LGALS3, SLC51B and SPP1, and negatively with SQLE expressions. When these genes were tested in a second experiment of NASH reversion, LGALS3, SLC51B and SPP1 significantly decreased their expression. However, only LGALS3 was associated with lipid droplet areas. Our results suggest a role for LGALS3 in the transition of NAFLD to NASH.

Genome-wide single nucleotide polymorphism array and whole-genome sequencing reveal the inbreeding progression of Banna minipig inbred line

Inbred pigs are promising animal models for biomedical research and xenotransplantation. Established in 1980, the Banna minipig inbred (BMI) line originated from a sow and its own male offspring. It was selected from a small backcountry minority Lahu village, where records show that no other pig breed has ever been introduced. During the inbreeding process, we perfomed extreme inbreeding over 23 consecutive generations using full-sibling or parent-offspring mating. In order to investigate the inbreeding effects in BMI pigs across generations over the past 40 years, in this study we conducted a genome-wide SNP genotyping of the last 10 generations, representing generations 14-23. In total, we genotyped 57,746 SNPs, corresponding to an average decrease in heterozygosity rate of 0.0078 per generation. Furthermore, we were only able to identify 18,216 polymorphic loci with a MAF larger than 0.05, which is substantially lower than the values in previous reports on other pig breeds. In addition, we sequenced the genome of the first pig in the twenty-third generation (inbreeding coefficient 99.28%) to an average coverage of 12.4× to evaluate at the genome level the impact of advanced inbreeding. ROH analysis indicates that BMI pigs have longer ROHs than Wuzhishan and Duroc pigs. Those long ROH regions in BMI pigs are enriched for distinct functions compared with the highly polymorphic regions. Our study reveals a genome-wide allele diversity loss during the progress of inbreeding in BMI pigs and characterizes ROH and polymorphic regions as a result of inbreeding. Overall, our results indicate the successful establishment of the BMI line, which paves the way for further in-depth studies.

Porcine pancreatic ductal epithelial cells transformed with KRASG12D and SV40T are tumorigenic

We describe our initial studies in the development of an orthotopic, genetically defined, large animal model of pancreatic cancer. Primary pancreatic epithelial cells were isolated from pancreatic duct of domestic pigs. A transformed cell line was generated from these primary cells with oncogenic KRAS and SV40T. The transformed cell lines outperformed the primary and SV40T immortalized cells in terms of proliferation, population doubling time, soft agar growth, transwell migration and invasion. The transformed cell line grew tumors when injected subcutaneously in nude mice, forming glandular structures and staining for epithelial markers. Future work will include implantation studies of these tumorigenic porcine pancreatic cell lines into the pancreas of allogeneic and autologous pigs. The resultant large animal model of pancreatic cancer could be utilized for preclinical research on diagnostic, interventional, and therapeutic technologies.

A porcine brain-wide RNA editing landscape

Adenosine-to-inosine (A-to-I) RNA editing, catalyzed by ADAR enzymes, is an essential post-transcriptional modification. Although hundreds of thousands of RNA editing sites have been reported in mammals, brain-wide analysis of the RNA editing in the mammalian brain remains rare. Here, a genome-wide RNA-editing investigation is performed in 119 samples, representing 30 anatomically defined subregions in the pig brain. We identify a total of 682,037 A-to-I RNA editing sites of which 97% are not identified before. Within the pig brain, cerebellum and olfactory bulb are regions with most edited transcripts. The editing level of sites residing in protein-coding regions are similar across brain regions, whereas region-distinct editing is observed in repetitive sequences. Highly edited conserved recoding events in pig and human brain are found in neurotransmitter receptors, demonstrating the evolutionary importance of RNA editing in neurotransmission functions. Although potential data biases caused by age, sex or health status are not considered, this study provides a rich resource to better understand the evolutionary importance of post-transcriptional RNA editing.

Role of astaxanthin as an efficient antioxidant on the in vitro maturation and vitrification of porcine oocytes

As one of the most powerful natural antioxidants, astaxanthin (Ax) has begun to be applied to the field of reproductive biology. Here we used porcine oocyte as a model to explore how Ax improves the oocyte potential during in vitro maturation (IVM), and we also investigated the cytoprotective effects of Ax on the vitrified oocytes. Ax supplementation (final concentration of 2.5 μM) was subjected for immature oocytes during vitrification and subsequent IVM; fresh oocytes were also matured in vitro in the presence or absence of 2.5 μM Ax. Our results showed that Ax significantly increased the survival rate of vitrified oocytes, and promoted the blastocyst yield of both fresh and vitrified oocytes after parthenogenetic activation and somatic cell nuclear transfer. The oocytes treated with Ax displayed significantly lower reactive oxygen species generation and higher glutathione level. Vitrification of oocytes had no impact on caspase-3, cathepsin B and autophagic activities; Ax significantly decreased the cathepsin B activity in both fresh and vitrified oocytes. Moreover, the relative fluorescence intensity of lysosomes was significantly increased in vitrified oocytes, which was recovered by Ax treatment. The mitochondrial activity did not differ between fresh and vitrified oocytes, and was significantly enhanced in Ax-treated oocytes. Furthermore, Ax significantly restored the decreased expression of BMP15, ZAR1, POU5F1, GPX4 and LAMP2 genes in vitrified oocytes. Both fresh and vitrified oocytes treated with Ax showed significantly higher mRNA levels of GDF9, POU5F1, SOD2, NRF2 and ATG5. Taken together, this study provides new perspectives in understanding the mechanisms by which Ax improves the developmental competence of both fresh and vitrified porcine oocytes.

Flufenoxuron disturbs early pregnancy in pigs via induction of cell death with ER-mitochondrial dysfunction

The use of pesticides can result in unintended side effects, such as environmental pollution and animal diseases; in serious cases, it may cause abortion. Flufenoxuron is an inhibitor of chitin synthesis that is used widely as a pesticide on farmland. It is difficult to break down and therefore accumulates in the body, and has also been detected in breast milk. Moreover, the effects of flufenoxuron in pregnancy remain elusive. Therefore, we investigated the effects of flufenoxuron on early pregnancy. Our results suggested that flufenoxuron inhibits cell development and cell cycle progression in porcine trophectoderm (pTr) cell and porcine endometrial luminal epithelial (pLE) cell lines through the repression of signal transduction pathways. Flufenoxuron induced programmed cell death through DNA fragmentation and apoptotic signals. In addition, flufenoxuron induced ROS production, ER stress, and mitochondrial malfunction; consequently, the cytosolic and mitochondrial calcium levels were increased. Expression of proteins on the ER-mitochondrial axis was increased by flufenoxuron. Cell migration was decreased by flufenoxuron treatment between pLE and pTr cells. In addition, the expression of pregnancy-related genes was decreased flufenoxuron. Collectively, our results indicated that flufenoxuron may be harmful to livestock and women in the early stages of pregnancy.

Tissue-based biosensor for monitoring the antioxidant effect of orally administered drugs in the intestine

For a better understanding of the effect of drugs and their interaction with cells and tissues, there is a need for in vitro and ex vivo model systems which enables studying these events. There are several in vitro methods available to evaluate the antioxidant activity; however, these methods do not factor in the complex in vivo physiology. Here we present an intestinal tissue modified oxygen electrode, used for the detection of the antioxidant effect of orally administered drugs in the presence of H₂O₂. Antioxidants are essential in the defense against oxidative stress, more specifically against reactive oxygen species such as H₂O_2. Due to the presence of native catalase in the intestine, with the tissue-based biosensor we were able to detect H₂O₂ in the range between 50 and 500 µM. The reproducibility of the sensor based on the calculated relative standard deviations was 15 ± 6%. We found that the O₂ production by catalase from H₂O₂ was reduced in the presence of a well-known antioxidant, quinol. This indirectly detected antioxidant activity was also observed in the case of orally administered drugs with a reported anti-inflammatory effect such as mesalazine and paracetamol, while no antioxidant activity was recorded with aspirin and metformin.

Human small intestinal organotypic culture model for drug permeation, inflammation, and toxicity assays

The gastrointestinal tract (GIT), in particular, the small intestine, plays a significant role in food digestion, fluid and electrolyte transport, drug absorption and metabolism, and nutrient uptake. As the longest portion of the GIT, the small intestine also plays a vital role in protecting the host against pathogenic or opportunistic microbial invasion. However, establishing polarized intestinal tissue models in vitro that reflect the architecture and physiology of the gut has been a challenge for decades and the lack of translational models that predict human responses has impeded research in the drug absorption, metabolism, and drug-induced gastrointestinal toxicity space. Often, animals fail to recapitulate human physiology and do not predict human outcomes. Also, certain human pathogens are species specific and do not infect other hosts. Concerns such as variability of results, a low throughput format, and ethical considerations further complicate the use of animals for predicting the safety and efficacy xenobiotics in humans. These limitations necessitate the development of in vitro 3D human intestinal tissue models that recapitulate in vivo–like microenvironment and provide more physiologically relevant cellular responses so that they can better predict the safety and efficacy of pharmaceuticals and toxicants. Over the past decade, much progress has been made in the development of in vitro intestinal models (organoids and 3D-organotypic tissues) using either inducible pluripotent or adult stem cells. Among the models, the MatTek’s intestinal tissue model (EpiIntestinal™ Ashland, MA) has been used extensively by the pharmaceutical industry to study drug permeation, metabolism, drug-induced GI toxicity, pathogen infections, inflammation, wound healing, and as a predictive model for a clinical adverse outcome (diarrhea) to pharmaceutical drugs. In this paper, our review will focus on the potential of in vitro small intestinal tissues as preclinical research tool and as alternative to the use of animals.

A decade of experience with genetically tailored pig models for diabetes and metabolic research

The global prevalence of diabetes mellitus and other metabolic diseases is rapidly increasing. Animal models play pivotal roles in unravelling disease mechanisms and developing and testing therapeutic strategies. Rodents are the most widely used animal models but may have limitations in their resemblance to human disease mechanisms and phenotypes. Findings in rodent models are consequently often difficult to extrapolate to human clinical trials. To overcome this ‘translational gap’, we and other groups are developing porcine disease models. Pigs share many anatomical and physiological traits with humans and thus hold great promise as translational animal models. Importantly, the toolbox for genetic engineering of pigs is rapidly expanding. Human disease mechanisms and targets can therefore be reproduced in pigs on a molecular level, resulting in precise and predictive porcine (PPP) models. In this short review, we summarize our work on the development of genetically (pre)diabetic pig models and how they have been used to study disease mechanisms and test therapeutic strategies. This includes the generation of reporter pigs for studying beta-cell maturation and physiology. Furthermore, genetically engineered pigs are promising donors of pancreatic islets for xenotransplantation. In summary, genetically tailored pig models have become an important link in the chain of translational diabetes and metabolic research.

Postnatal differentiation and regional histological variations in the ductus epididymidis of the Congjiang Xiang pig

The Congjiang Xiang pig is a rare Chinese miniature breed whose epididymal histologic features through the postnatal development are poorly understood. To clarify the histomorphological differences between each region of epididymis during postnatal development, 24 male Congjiang Xiang pigs aged from neonatal (15 d), peri-puberty (30 d), puberty (60 d) to adult (180 d) stages, were examined. Postnatal differentiation of the different regions (I-V) of the epididymis started from birth and continued until maturity that showed regional variations. Developmental progression was disto-proximal. At the neonatal stage, Wolffian duct differentiation starts in the distal region, then ascends to the middle region which forms regions V, IV and III, respectively. A simple lined cuboidal in the epidydimal epithelial, which gradually differentiated into a pseudostratified columnar with stereocilia from neonatal to post-pubertal. After puberty cell rearrangement occurred in the epithelium, differentiation accelerated, and spermatozoon seen in the lumen, especially the lumen of region II. In region III, both halo and apical cells were frequently observed. At the post-pubertal stage, clear cells were frequently observed in Region IV-V, and the epididymal duct was markedly increased in size and fully packed with spermatozoa. The information presented in this study will be helpful for future evaluations of Congjiang Xiang pig fertility. After puberty cell rearrangement occurred in the epithelium, differentiation accelerated, and spermatozoon seen in the lumen, especially the lumen of region II. In region III, both halo and apical cells were frequently observed. At the post-pubertal stage, clear cells were frequently observed in Region IV-V, and the epididymal duct was markedly increased in size and fully packed with spermatozoa. The information presented in this study will be helpful for future evaluations of Congjiang Xiang pig fertility.

Validating indicators of CNS disorders in a swine model of neurological disease

Genetically modified swine disease models are becoming increasingly important for studying molecular, physiological and pathological characteristics of human disorders. Given the limited history of these model systems, there remains a great need for proven molecular reagents in swine tissue. Here, to provide a resource for neurological models of disease, we validated antibodies by immunohistochemistry for use in examining central nervous system (CNS) markers in a recently developed miniswine model of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant tumor predisposition disorder stemming from mutations in NF1, a gene that encodes the Ras-GTPase activating protein neurofibromin. Patients classically present with benign neurofibromas throughout their bodies and can also present with neurological associated symptoms such as chronic pain, cognitive impairment, and behavioral abnormalities. As validated antibodies for immunohistochemistry applications are particularly difficult to find for swine models of neurological disease, we present immunostaining validation of antibodies implicated in glial inflammation (CD68), oligodendrocyte development (NG2, O4 and Olig2), and neuron differentiation and neurotransmission (doublecortin, GAD67, and tyrosine hydroxylase) by examining cellular localization and brain region specificity. Additionally, we confirm the utility of anti-GFAP, anti-Iba1, and anti-MBP antibodies, previously validated in swine, by testing their immunoreactivity across multiple brain regions in mutant NF1 samples. These immunostaining protocols for CNS markers provide a useful resource to the scientific community, furthering the utility of genetically modified miniswine for translational and clinical applications.

Function of CCL5 in maternal-fetal interface of pig during early pregnancy

Chemokines refer to chemoattractant cytokines, which have crucial functions in inflammation and immune responses in multiple cellular processes. In the present study, we described the potential role of porcine CCL5 in embryo implantation and fetal-maternal environment during early pregnancy. We first carried out phylogenetic analysis of porcine CCL5, and analyzed the cell specific localization of CCL5 and its receptor CCR3 in a kinetic approach within porcine estrous cycles and early gestation stage. In addition, CCL5 stimulated porcine uterine luminal epithelial (pLE) and porcine trophectoderm (pTr) cell proliferations, and cell cycle progressions via AKT and MAPK intracellular signaling tractions. Furthermore, CCL5 attenuated tunicamycin-induced endoplasmic reticulum (ER) stress signaling, and lipopolysaccharides-triggered inflammatory responses in pLE and pTr cells. Taken together, our study showed that CCL5 is involved in the placental development or promotes the placental development.

Models of the Gut for Analyzing the Impact of Food and Drugs

Models of the human gastrointestinal tract (GIT) can be powerful tools for examining the biological interactions of food products and pharmaceuticals. This can be done under normal healthy conditions or using models of disease-many of which have no curative therapy. This report outlines the field of gastrointestinal modeling, with a particular focus on the intestine. Traditional in vivo animal models are compared to a range of in vitro models. In vitro systems are elaborated over time, recently culminating with microfluidic intestines-on-chips (IsOC) and 3D bioengineered models. Macroscale models are also reviewed for their important contribution in the microbiota studies. Lastly, it is discussed how in silico approaches may have utility in predicting and interpreting experimental data. The various advantages and limitations of the different systems are contrasted. It is posited that only through complementary use of these models will salient research questions be able to be addressed.

OSBPL2-disrupted pigs recapitulate dual features of human hearing loss and hypercholesterolaemia

Oxysterol binding protein like 2 (OSBPL2), an important regulator in cellular lipid metabolism and transport, was identified as a novel deafness-causal gene in our previous work. To resemble the phenotypic features of OSBPL2 mutation in animal models and elucidate the potential genotype-phenotype associations, the OSBPL2-disrupted Bama miniature (BM) pig model was constructed using CRISPR/Cas9-mediated gene editing, somatic cell nuclear transfer (SCNT) and embryo transplantation approaches, and then subjected to phenotypic characterization of auditory function and serum lipid profiles. The OSBPL2-disrupted pigs displayed progressive hearing loss (HL) with degeneration/apoptosis of cochlea hair cells (HCs) and morphological abnormalities in HC stereocilia, as well as hypercholesterolaemia. High-fat diet (HFD) feeding aggravated the development of HL and led to more severe hypercholesterolaemia. The dual phenotypes of progressive HL and hypercholesterolaemia resembled in OSBPL2-disrupted pigs confirmed the implication of OSBPL2 mutation in nonsydromic hearing loss (NSHL) and contributed to the potential linkage between auditory dysfunction and dyslipidaemia/hypercholesterolaemia.

Breed, Diet, and Interaction Effects on Adipose Tissue Transcriptome in Iberian and Duroc Pigs Fed Different Energy Sources

In this study, we analyzed the effects of breed, diet energy source, and their interaction on adipose tissue transcriptome in growing Iberian and Duroc pigs. The study comprised 29 Iberian and 19 Duroc males, which were kept under identical management conditions except the nutritional treatment. Two isoenergetic diets were used with 6% high oleic sunflower oil (HO) or carbohydrates (CH) as energy sources. All animals were slaughtered after 47 days of treatment at an average live weight of 51.2 kg. Twelve animals from each breed (six fed each diet) were employed for ham subcutaneous adipose tissue RNA-Seq analysis. The data analysis was performed using two different bioinformatic pipelines. We detected 837 and 1456 differentially expressed genes (DEGs) according to breed, depending on the pipeline. Due to the strong effect of breed on transcriptome, the effect of the diet was separately evaluated in the two breeds. We identified 207 and 57 DEGs depending on diet in Iberian and Duroc pigs, respectively. A joint analysis of both effects allowed the detection of some breed–diet interactions on transcriptome, which were inferred from RNA-Seq and quantitative PCR data. The functional analysis showed the enrichment of functions related to growth and tissue development, inflammatory response, immune cell trafficking, and carbohydrate and lipid metabolism, and allowed the identification of potential regulators. The results indicate different effects of diet on adipose tissue gene expression between breeds, affecting relevant biological pathways.

El biomodelo porcino en la investigación médica traslacional: del biomodelo al humano en trasplante pulmonar

Introducción. La anatomía humana y porcina son comparables. En consecuencia, el biomodelo porcino tiene el potencial de ser implementado para entrenar al profesional quirúrgico en áreas como el trasplante de órganos sólidos.Objetivo. Describir los procedimientos y hallazgos obtenidos mediante experimentos de medicina respiratoria traslacional con biomodelos porcinos realizados en un laboratorio de experimentación animal, y hacer una revisión comparativa entre el pulmón humano y el porcino.Materiales y métodos. El experimento se llevó a cabo en nueve cerdos de raza híbrida en un laboratorio de cirugía experimental. Se estudiaron la anatomía y la histología de las vías respiratorias mediante fibrobroncoscopia, biopsia bronquial y lavado broncoalveolar. El lavado broncoalveolar se estudió con citología en base líquida y se evaluó con las coloraciones de Papanicolau y hematoxilina y eosina. Se utilizaron técnicas de patología molecular, como inmunohistoquímica, citometría de flujo y microscopía electrónica. Los cerdos se sometieron a neumonectomía izquierda con posterior implante del injerto en otro cerdo experimental.Resultados. Los estudios histopatológicos y moleculares evidenciaron un predominio de macrófagos alveolares (98 %) y linfocitos T (2 %) en el lavado broncoalveolar porcino. En los estudios del parénquima pulmonar porcino se encontró tejido linfoide hiperplásico asociado a las paredes bronquiales. La microscopía electrónica evidenció linfocitos T dentro del epitelio y el diámetro de las cilias porcinas fue similar al de las humanas.Conclusiones. El biomodelo porcino es viable en la investigación traslacional para el entendimiento de la anatomía del sistema respiratorio y el entrenamiento en trasplante pulmonar. La implementación de este modelo experimental podría fortalecer los grupos que planean implementar un programa institucional de trasplante pulmonar en humanos.

Whole-Tooth Regeneration by Allogeneic Cell Reassociation in Pig Jawbone

IMPACT STATEMENT

The methods developed in this study to manipulate pig tooth germ cells in vitro and in vivo provide a reference for studying whole-tooth regeneration and tooth development in large animals. Of importance, compared with conventional ectopic tooth regeneration, conducted in the omentum, subcutaneous tissues, or kidney capsule (among other locations) with low with immune reactivity in rodent models, this study achieved orthotopic regeneration and development of whole teeth in a large mammal, representing a large stride toward the realization of tooth regenerative therapy for humans with missing teeth.

Porcine Models of Pancreatic Cancer

Pancreatic cancer is the fourth most common cause of cancer-related deaths in both men and women. The 5-year survival rate for metastatic pancreatic cancer is only 8%. There remains a need for improved early diagnosis and therapy for pancreatic cancer. Murine models are the current standard for preclinical study of pancreatic cancer. However, mice may not accurately reflect human biology because of a variety of differences between the two species. Remarkably, only 5-8% of anti-cancer drugs that have emerged from preclinical studies and entered clinical studies have ultimately been approved for clinical use. The cause of this poor approval rate is multi-factorial, but may in part be due to use of murine models that have limited accuracy with respect to human disease. Murine models also have limited utility in the development of diagnostic or interventional technology that require a human-sized model. So, at present, there remains a need for improved animal models of pancreatic cancer. The rationale for a porcine model of pancreatic cancer is (i) to enable development of diagnostic/therapeutic devices for which murine models have limited utility; and (ii) to have a highly predictive preclinical model in which anti-cancer therapies can be tested and optimized prior to a clinical trial. Recently, pancreatic tumors were induced in transgenic Oncopigs and porcine pancreatic ductal cells were transformed that contain oncogenic KRAS and p53-null mutations. Both techniques to induce pancreatic tumors in pigs are undergoing further refinement and expansion. The Oncopig currently is commercially available, and it is conceivable that other porcine models of pancreatic cancer may be available for general use in the near future.

Improvement of in vitro and early in utero porcine clone development after somatic donor cells are cultured under hypoxia

Genetically engineered pigs serve as excellent biomedical and agricultural models. To date, the most reliable way to generate genetically engineered pigs is via somatic cell nuclear transfer (SCNT), however, the efficiency of cloning in pigs is low (1-3%). Somatic cells such as fibroblasts frequently used in nuclear transfer utilize the tricarboxylic acid cycle and mitochondrial oxidative phosphorylation for efficient energy production. The metabolism of somatic cells contrasts with cells within the early embryo, which predominately use glycolysis. We hypothesized that fibroblast cells could become blastomere-like if mitochondrial oxidative phosphorylation was inhibited by hypoxia and that this would result in improved in vitro embryonic development after SCNT. In a previous study, we demonstrated that fibroblasts cultured under hypoxic conditions had changes in gene expression consistent with increased glycolytic/gluconeogenic metabolism. The goal of this pilot study was to determine if subsequent in vitro embryo development is impacted by cloning porcine embryonic fibroblasts cultured in hypoxia. Here we demonstrate that in vitro measures such as early cleavage, blastocyst development, and blastocyst cell number are improved (4.4%, 5.5%, and 17.6 cells, respectively) when donor cells are cultured in hypoxia before nuclear transfer. Survival probability was increased in clones from hypoxic cultured donors compared to controls (8.5 vs. 4.0 ± 0.2). These results suggest that the clones from donor cells cultured in hypoxia are more developmentally competent and this may be due to improved nuclear reprogramming during somatic cell nuclear transfer.

Tracking diphyodont development in miniature pigs in vitro and in vivo

Abnormalities of tooth number in humans, such as agenesis and supernumerary tooth formation, are closely related to diphyodont development. There is an increasing demand to understand the molecular and cellular mechanisms behind diphyodont development through the use of large animal models, since they are the most similar to the mechanism of human tooth development. However, attempting to study diphyodont development in large animals remains challenging due to large tooth size, prolonged growth stage and embryo manipulation. Here, we characterized the expression of possible genes for diphyodont development and odontogenesis of an organoid bud from single cells of tooth germs in vitro using Wzhishan pig strain (WZSP). Following this, we used a method of ectopic transplantation of tooth germs at cap stage to dynamically track diphyodont development of tooth germs in mouse subrenal capsules to overcome the restrictions in pig embryos. The results showed that pig tooth germ at cap stage could restore diphyodont development and maintain efficient long-term survival and growth in mouse subrenal capsules, which is suitable for future manipulation of large mammalian tooth development. Our pilot study provided an alternative for studying diphyodont development in large mammals, which will further promote the use of pig as a diphyodont model similar to humans for craniofacial development study.

Summary: Little is known about diphyodont development in large animals. Our pilot trial characterized this gene expression and developed an alternative method to track diphyodont development in pigs.

Dietary Factors in Prevention of Pediatric Escherichia coli Infection: A Model Using Domestic Piglets

Enterotoxigenic Escherichia coli (ETEC) is the major etiological agent causing acute watery diarrhea that is most frequently seen in young children in lower-income countries. The duration of diarrheal symptom may be shortened by antibiotic treatment, but ETEC is relative refractory to common antibiotics. Burgeoning evidence suggests bioactive components that naturally occur in human milk (e.g., lysozyme and oligosaccharides) and plants (e.g., nondigestible carbohydrates and phytochemicals) contain antimicrobial functions are promising preventive measures to control ETEC infection. Although the exact protective mechanisms may vary for each compound and are still not completely understood, they generally act to (1) competitively inhibit the binding of pathogenic bacteria and toxins to gut epithelium; (2) directly kill pathogens; and (3) stimulate and/or enhance host mucosal and systemic immune defense against pathogenic microorganisms. An appropriate ETEC-challenge animal model is critical to evaluate the effect and unveil the mechanism of bioactive compounds in prevention of enteric infection. Despite wide application in biomedical research, rodents do not usually manifest typical clinical signs of enteric infections. The remarkable differences in digestive physiology, immune response, and gut microbiota between rodents and human beings necessitate the use of alternative animal models. Pigs are closely related to humans in terms of genomes, physiology, anatomy of gastrointestinal tracts, digestive enzymes, components of immune system, and gut microbiota. Like human infants and young children, nursing and nursery piglets are more susceptible to ETEC infection and reproduce the clinical signs as observed in humans. Hence, the ETEC-challenge piglet represents a valuable translational model to study pathogenesis and evaluate dietary factors (e.g., milk bioactive compounds, nondigestible carbohydrates, and phytochemicals) as preventive measures for ETEC infection in pediatrics.

The first comprehensive description of the expression profile of genes involved in differential body growth and the immune system of the Jeju Native Pig and miniature pig

Sus scrofa provides a major source of animal protein for humans as well as being an excellent biomedical model. This study was carried out to understand, in detail, the genetic and functional variants of Jeju Native Pigs and miniature pigs through differential expression profiling of the genes controlling their immune response, growth performance, and meat quality. The Illumina HiSeq 2000 platform was used for generating 1.3 billion 90 bp paired-end reads, which were mapped to the S. scrofa genome using TopHat2. A total of 2481 and 2768 genes were differentially expressed with 8-log changes in muscle and liver samples, respectively. Five hundred forty-eight genes in muscle and 642 genes in liver samples had BLAST matches within the non-redundant database. GO process and pathway analyses showed enhanced biological processes related to the extracellular structural organization and skeletal muscle cell differentiation in muscle tissue, whereas the liver tissue shares functions related to the inflammatory response. Herein, we identify inflammatory regulatory genes in miniature pigs and growth response genes in Jeju Native Pigs, information which can provide a stronger base for the selection of breeding stock and facilitate further in vitro and in vivo studies for therapeutic purposes.

The evolutionary dynamics of microRNAs in domestic mammals

MiRNAs are crucial regulators of gene expression found across both the plant and animal kingdoms. While the number of annotated miRNAs deposited in miRBase has greatly increased in recent years, few studies provided comparative analyses across sets of related species, or investigated the role of miRNAs in the evolution of gene regulation. We generated small RNA libraries across 5 mammalian species (cow, dog, horse, pig and rabbit) from 4 different tissues (brain, heart, kidney and testis). We identified 1676 miRBase and 413 novel miRNAs by manually curating the set of computational predictions obtained from miRCat and miRDeep2. Our dataset spanning five species has enabled us to investigate the molecular mechanisms and selective pressures driving the evolution of miRNAs in mammals. We highlight the important contributions of intronic sequences (366 orthogroups), duplication events (135 orthogroups) and repetitive elements (37 orthogroups) in the emergence of new miRNA loci. We use this framework to estimate the patterns of gains and losses across the phylogeny, and observe high levels of miRNA turnover. Additionally, the identification of lineage-specific losses enables the characterisation of the selective constraints acting on the associated target sites. Compared to the miRBase subset, novel miRNAs tend to be more tissue specific. 20 percent of novel orthogroups are restricted to the brain, and their target repertoires appear to be enriched for neuron activity and differentiation processes. These findings may reflect an important role for young miRNAs in the evolution of brain expression plasticity. Many seed sequences appear to be specific to either the cow or the dog. Analyses on the associated targets highlight the presence of several genes under artificial positive selection, suggesting an involvement of these miRNAs in the domestication process. Altogether, we provide an overview on the evolutionary mechanisms responsible for miRNA turnover in 5 domestic species, and their possible contribution to the evolution of gene regulation.

Downregulation of Aquaporins (AQP1 and AQP5) and Na,K-ATPase in Porcine Reproductive and Respiratory Syndrome Virus-Infected Pig Lungs

Aquaporins (AQPs) and Na,K-ATPase control water transport across the air space-capillary barrier in the distal lung and play an important role in the formation and resolution of lung edema. Porcine reproductive and respiratory syndrome virus (PRRSV) infection usually causes pulmonary inflammation and edema in the infected pig lungs. To investigate the possibility that PRRSV infection may cause altered expression of AQPs and Na,K-ATPase messenger RNA (mRNA) levels and protein expression of AQP1, AQP5, and Na,K-ATPase in the PRRSV-infected pig lungs were detected. Quantitative real-time PCR (qRT-PCR) analysis showed markedly decreased mRNA levels of AQP1 and AQP5 and Na,K-ATPase in the PRRSV-infected pig lungs compared to those of uninfected pig lungs. Western blot studies also revealed significantly reduced levels of AQP1, AQP5, and Na,K-ATPase proteins in the PRRSV-infected pig lungs. In addition, immunohistochemical (IHC) analysis showed decreased protein expression of AQP1 and AQP5 in the endothelial cells of the capillaries and venules and secretory cells of terminal bronchiole and the alveolar type I cells, respectively. The expression of Na,K-ATPase in the basolateral membrane of alveolar type II cells presented great reduction in the PRRSV-infected pig lungs. To further understand the reduction of these proteins, the ubiquitination of AQP1 and Na,K-ATPase was examined in uninfected and PRRSV-infected pig lungs. The results showed that there is no difference of ubiquitination for these proteins. Thus, our results suggest that PRRSV infection may induce downregulation of these proteins and cause impairment of edema resolution by failed water clearance in the infected pig lungs.

Fast and reliable dissection of porcine parathyroid glands - A protocol for molecular and histological analyses

As calcium and phosphorus are of vital importance for life, physiological activity of the parathyroid glands (PTGs) is crucial to maintain mineral homeostasis and bone mineralization. However, PTG-specific molecular routes in response to environmental factors and intrinsic hormonal responses are not yet fully understood. Since nutrient requirements, pathophysiology and functional genomics of pigs are similar to those of humans, pigs might be a suitable model to study the holistic gene expression and physiological aspects of the parathyroid gland, which could be used in both animal sciences and biomedical research. However, due to their small size and hidden location, the dissection of the PTGs, particularly in pigs, is difficult. Therefore, a protocol for untrained dissectors has been established that allows a fast and reliable identification of the PTGs in domestic pigs. Based on their localization within the cranial thymus near the carotid bifurcation, sampling was verified by histological staining and mRNA expression pattern. Analyses revealed the prominence of parathyroid hormone (PTH)-producing chief cells. Moreover, the copy numbers of PTH differed substantially between the PTGs and their surrounding thymus tissue, as PTH was expressed virtually exclusively in the PTGs. The developed protocol will substantially facilitate a fast and reliable dissection of porcine PTGs which is essential for studies characterizing the molecular mechanisms of parathyroid glands, e.g. when applying new feeding strategies in pigs.

Ergot Alkaloids at Doses Close to EU Regulatory Limits Induce Alterations of the Liver and Intestine

An increase in the occurrence of ergot alkaloids (EAs) contamination has been observed in North America and Europe in recent years. These toxins are well known for their effects on the circulatory and nervous systems. The aim of this study was to investigate the effect of EAs on the liver and on the intestine using the pig both as a target species and as a non-rodent model for human. Three groups of 24 weaned piglets were exposed for 28 days to control feed or feed contaminated with 1.2 or 2.5 g of sclerotia/kg, i.e., at doses close to EU regulatory limits. Contaminated diets significantly reduced feed intake and consequently growth performance. In the liver, alteration of the tissue, including development of inflammatory infiltrates, vacuolization, apoptosis and necrosis of hepatocytes as well as presence of enlarged hepatocytes (megalocytes) were observed. In the jejunum, EAs reduced villi height and increased damage to the epithelium, reduced the number of mucus-producing cells and upregulated mRNA coding for different tight junction proteins such as claudins 3 and 4. In conclusion, in term of animal health, our data indicate that feed contaminated at the regulatory limits induces lesions in liver and intestine suggesting that this limit should be lowered for pigs. In term of human health, we establish a lowest observed adverse effect level (LOAEL) of 100 μg/kg body weight (bw) per day, lower than the benchmark dose limit (BMDL) retained by European Food Safety Authority (EFSA) to set the tolerable daily intake, suggesting also that regulatory limit should be revised.

Pharmacologic treatment of donor cells induced to have a Warburg effect-like metabolism does not alter embryonic development in vitro or survival during early gestation when used in somatic cell nuclear transfer in pigs

Somatic cell nuclear transfer is a valuable technique for the generation of genetically engineered animals, however, the efficiency of cloning in mammalian species is low (1-3%). Differentiated somatic cells commonly used in nuclear transfer utilize the tricarboxylic acid cycle and cellular respiration for energy production. Comparatively the metabolism of somatic cells contrasts that of the cells within the early embryos which predominately use glycolysis. Early embryos (prior to implantation) are evidenced to exhibit characteristics of a Warburg Effect (WE)-like metabolism. We hypothesized that pharmacologically driven fibroblast cells can become more blastomere-like and result in improved in vitro embryonic development after SCNT. The goals were to determine if subsequent in vitro embryo development is impacted by (1) cloning pharmacologically treated donor cells pushed to have a WE-like metabolism or (2) culturing non-treated donor clones with pharmaceuticals used to push a WE-like metabolism. Additionally, we investigated early gestational survival of the donor-treated clone embryos. Here we demonstrate that in vitro development of clones is not hindered by pharmacologically treating either the donor cells or the embryos themselves with CPI, PS48, or the combination of these drugs. Furthermore, these experiments demonstrate that early embryos (or at least in vitro produced embryos) have a low proportion of mitochondria which have high membrane potential and treatment with these pharmaceuticals does not further alter the mitochondrial function in early embryos. Lastly, we show that survival in early gestation was not different between clones from pharmacologically induced WE-like donor cells and controls.

Endothelial dysfunction occurs independently of adipose tissue inflammation and insulin resistance in ovariectomized Yucatan miniature-swine

In rodents, experimentally-induced ovarian hormone deficiency increases adiposity and adipose tissue (AT) inflammation, which is thought to contribute to insulin resistance and increased cardiovascular disease risk. However, whether this occurs in a translationally-relevant large animal model remains unknown. Herein, we tested the hypothesis that ovariectomy would promote visceral and perivascular AT (PVAT) inflammation, as well as subsequent insulin resistance and peripheral vascular dysfunction in female swine. At sexual maturity (7 months of age), female Yucatan mini-swine either remained intact (control, n = 9) or were ovariectomized (OVX, n = 7). All pigs were fed standard chow (15-20 g/kg), and were euthanized 6 months post-surgery. Uterine mass and plasma estradiol levels were decreased by ∼10-fold and 2-fold, respectively, in OVX compared to control pigs. Body mass, glucose homeostasis, and markers of insulin resistance were not different between control and OVX pigs; however, OVX animals exhibited greater plasma triglycerides and triglyceride:HDL ratio. Ovariectomy enhanced visceral adipocyte expansion, although this was not accompanied by brachial artery PVAT adipocyte expansion, AT inflammation in either depot, or increased systemic inflammation assessed by plasma C-reactive protein concentrations. Despite the lack of AT inflammation and insulin resistance, OVX pigs exhibited depressed brachial artery endothelial-dependent vasorelaxation, which was rescued with blockade of endothelin receptor A. Together, these findings indicate that in female Yucatan mini-swine, increased AT inflammation and insulin resistance are not required for loss of ovarian hormones to induce endothelial dysfunction.

Interactions between human microbiome, diet, enteric viruses and immune system: Novel insights from gnotobiotic pig research

Studies over the past few decades demonstrated that gnotobiotic (Gn) pigs provide an unprecedented translational model to study human intestinal health and diseases. Due to the high degree of anatomical, physiological, metabolic, immunological, and developmental similarity, the domestic pig closely mimics the human intestinal microenvironment. Also, Gn piglets can be efficiently transplanted with human microbiota from infants, children and adults with resultant microbial profiles remarkably similar to the original human samples, a feat consistently not achievable in rodent models. Finally, Gn and human microbiota-associated (HMA) piglets are susceptible to human enteric viral pathogens (including human rotavirus, HRV) and can be fed authentic human diets, which further increases the translational potential of these models. In this review, we will focus on recent studies that evaluated the pathophysiology of protein malnutrition and the associated dysbiosis and immunological dysfunction in neonatal HMA piglets. Additionally, we will discuss studies of potential dietary interventions that moderate the effects of malnutrition and dysbiosis on antiviral immunity and HRV vaccines in HMA pigs. Such studies provide novel models and novel mechanistic insights critical for development of drug interventions.

Genome-wide profiling of Sus scrofa circular RNAs across nine organs and three developmental stages

The spatio-temporal expression patterns of Circular RNA (circRNA) across organs and developmental stages are critical for its function and evolution analysis. However, they remain largely unclear in mammals. Here, we comprehensively analysed circRNAs in nine organs and three skeletal muscles of Guizhou miniature pig (S. scrofa), a widely used biomedical model animal. We identified 5,934 circRNAs and analysed their molecular properties, sequence conservation, spatio-temporal expression pattern, potential function, and interaction with miRNAs. S. scrofa circRNAs show modest sequence conservation with human and mouse circRNAs, are flanked by long introns, exhibit low abundance, and are expressed dynamically in a spatio-temporally specific manner. S. scrofa circRNAs show the greatest abundance and complexity in the testis. Notably, 31% of circRNAs harbour well-conserved canonical miRNA seed matches, suggesting that some circRNAs act as miRNAs sponges. We identified 149 circRNAs potentially associated with muscle growth and found that their host genes were significantly involved in muscle development, contraction, chromatin modification, cation homeostasis, and ATP hydrolysis-coupled proton transport; moreover, this set of genes was markedly enriched in genes involved in tight junctions and the calcium signalling pathway. Finally, we constructed the first public S. scrofa circRNA database, allowing researchers to query comprehensive annotation, expression, and regulatory networks of circRNAs.

Genome-wide DNA methylation and transcriptome analyses reveal genes involved in immune responses of pig peripheral blood mononuclear cells to poly I:C

DNA methylation changes play essential roles in regulating the activities of genes involved in immune responses. Understanding of variable DNA methylation linked to immune responses may contribute to identifying biologically promising epigenetic markers for pathogenesis of diseases. Here, we generated genome-wide DNA methylation and transcriptomic profiles of six pairs of polyinosinic-polycytidylic acid-treated pig peripheral blood mononuclear cell (PBMC) samples and corresponding controls using methylated DNA immunoprecipitation sequencing and RNA sequencing. Comparative methylome analyses identified 5,827 differentially methylated regions and 615 genes showing differential expression between the two groups. Integrative analyses revealed inverse associations between DNA methylation around transcriptional start site and gene expression levels. Furthermore, 70 differentially methylated and expressed genes were identified such as TNFRSF9, IDO1 and EBI3. Functional annotation revealed the enriched categories including positive regulation of immune system process and regulation of leukocyte activation. These findings demonstrated DNA methylation changes occurring in immune responses of PBMCs to poly I:C stimulation and a subset of genes potentially regulated by DNA methylation in the immune responses. The PBMC DNA methylome provides an epigenetic overview of this physiological system in response to viral infection, and we expect it to constitute a valuable resource for future epigenetic epidemiology studies in pigs.

Swine models, genomic tools and services to enhance our understanding of human health and diseases

The pig is becoming increasingly important as a biomedical model. Given the similarities between pigs and humans, a greater understanding of the underlying biology of human health and diseases may come from the pig rather than from classical rodent models. With an increasing need for swine models, it is essential that the genomic tools, models and services be readily available to the scientific community. Many of these are available through the National Swine Resource and Research Center (NSRRC), a facility funded by the US National Institutes of Health at the University of Missouri. The goal of the NSRRC is to provide high-quality biomedical swine models to the scientific community.

Microbiome and NAFLD: potential influence of aerobic fitness and lifestyle modification

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease with prevalence rates that are on the rise in the US and worldwide. NAFLD encompasses a spectrum of liver pathologies including simple steatosis to nonalcoholic steatohepatitis (NASH) with inflammation and fibrosis. The gut microbiome has emerged as a potential therapeutic target in combating metabolic diseases including obesity, Type 2 diabetes, and NAFLD/NASH. Diet-induced obesity/Western style diet feeding causes severe microbial dysbiosis initiating a microbiome signature that promotes metabolite production that directly impacts hepatic metabolism. Changes in lifestyle (i.e., diet, exercise, and aerobic fitness) improve NAFLD outcomes and can significantly influence the microbiome. However, directly linking lifestyle-induced remodeling of the microbiome to NAFLD pathogenesis is not well understood. Understanding the reshaping of the microbiome and the metabolites produced and their subsequent actions on hepatic metabolism are vital in understanding the gut-liver axis. In this review, we 1) discuss microbiome-derived metabolites that significantly contribute to the gut-liver axis and are directly linked to NAFLD/NASH and 2) present evidence on lifestyle modifications reshaping the microbiome and the potential therapeutic aspects in combating the disease.

Hydrogel derived from decellularized porcine adipose tissue as a promising biomaterial for soft tissue augmentation

Decellularized extracellular matrix (ECM) scaffolds from human adipose tissue, characterized by impressive adipogenic induction ability, are promising for soft tissue augmentation. However, scaffolds from autologous human adipose tissue are limited by the availability of tissue resources and the time necessary for scaffold fabrication. The objective of the current study was to investigate the adipogenic properties of hydrogels of decellularized porcine adipose tissue (HDPA). HDPA induced the adipogenic differentiation of human adipose-derived stem cells (ADSCs) in vitro, with significantly increased expression of adipogenic genes. Subcutaneous injection of HDPA in immunocompetent mice induced host-derived adipogenesis without cell seeding, and adipogenesis was significantly enhanced with ADSCs seeding. The newly formed adipocytes were frequently located on the basal side in the non-seeding group, but this trend was not observed in the ADSCs seeding group. Our results indicated that, similar to human adipose tissue, the ECM scaffold derived from porcine adipose tissue could provide an adipogenic microenvironment for adipose tissue regeneration and is a promising biomaterial for soft tissue augmentation. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1756-1764, 2017.

Transcriptome analysis of coding and long non-coding RNAs highlights the regulatory network of cascade initiation of permanent molars in miniature pigs

Background

In diphyodont mammals, the additional molars (permanent molars) bud off from the posterior-free end of the primary dental lamina compared with successional teeth (replacement teeth) budding off from the secondary dental lamina. The diphyodont miniature pig has proved to be a valuable model for studying human molar morphogenesis. The additional molars show a sequential initiation pattern related to the specific tooth development stage of additional molars in miniature pigs during the morphogenesis of additional molars. However, the molecular mechanisms of the regulatory network of mRNAs and long non-coding RNAs during sequential formation of additional molars remain poorly characterized in diphyodont mammals. Here, we performed RNA-seq and microarray on miniature pigs at three key molar developmental stages to examine their differential gene expression profiles and potential regulatory networks during additional molar morphogenesis.

Results

We have profiled the differential transcript expression and functional networks during morphogenesis of additional molars in miniature pigs. We also have identified the coding and long non-coding transcripts using Coding-Non-Coding Index (CNCI) and annotated transcripts through mapping to the porcine, Wuzhishan miniature pig, mice, cow and human genomes. Many new unannotated genes plus 450 putative long intergenic non-coding RNAs (lincRNAs) were identified. Detailed regulatory network analyses reveal that WNT and TGF-β pathways are critical in regulating sequential morphogenesis of additional molars.

Conclusions

This is the first study to comprehensively analyze the spatiotemporal dynamics of coding and long non-coding transcripts during morphogenesis of additional molars in diphyodont mammals. The miniature pig serves as a large model animal to elucidate the relationship between morphogenesis and transcript level during the cascade initiation of additional molars. Our data provide fundamental knowledge and a basis for understanding the molecular mechanisms governing cascade initiation of additional molars, but also provide an important resource for developmental biology research.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3546-4) contains supplementary material, which is available to authorized users.

Effects of Culture Dimensions on Maintenance of Porcine Inner Cell Mass-Derived Cell Self-Renewal

Despite the fact that porcine embryonic stem cells (ESCs) are a practical study tool, in vitro long-term maintenance of these cells is difficult in a two-dimensional (2D) microenvironment using cellular niche or extracellular matrix proteins. However, a three-dimensional (3D) microenvironment, similar to that enclosing the inner cell mass of the blastocyst, may improve in vitro maintenance of self-renewal. Accordingly, as a first step toward constructing a 3D microenvironment optimized to maintain porcine ESC self-renewal, we investigated different culture dimensions for porcine ICM-derived cells to enhance the maintenance of self-renewal. Porcine ICM-derived cells were cultured in agarose-based 3D hydrogel with self-renewal-friendly mechanics and in 2D culture plates with or without feeder cells. Subsequently, the effects of the 3D microenvironment on maintenance of self-renewal were identified by analyzing colony formation and morphology, alkaline phosphatase (AP) activity, and transcriptional and translational regulation of self-renewal-related genes. The 3D microenvironment using a 1.5% (w/v) agarose-based 3D hydrogel resulted in significantly more colonies with stereoscopic morphology, significantly improved AP activity, and increased protein expression of self-renewal-related genes compared to those in the 2D microenvironment. These results demonstrate that self-renewal of porcine ICM-derived cells can be maintained more effectively in a 3D microenvironment than in a 2D microenvironment. These results will help develop novel culture systems for ICM-derived cells derived from diverse species, which will contribute to stimulating basic and applicable studies related to ESCs.

Miniature Swine for Preclinical Modeling of Complexities of Human Disease for Translational Scientific Discovery and Accelerated Development of Therapies and Medical Devices

Noncommunicable diseases, including cardiovascular disease, diabetes, chronic respiratory disease, and cancer, are the leading cause of death in the world. The cost, both monetary and time, of developing therapies to prevent, treat, or manage these diseases has become unsustainable. A contributing factor is inefficient and ineffective preclinical research, in which the animal models utilized do not replicate the complex physiology that influences disease. An ideal preclinical animal model is one that responds similarly to intrinsic and extrinsic influences, providing high translatability and concordance of preclinical findings to humans. The overwhelming genetic, anatomical, physiological, and pathophysiological similarities to humans make miniature swine an ideal model for preclinical studies of human disease. Additionally, recent development of precision gene-editing tools for creation of novel genetic swine models allows the modeling of highly complex pathophysiology and comorbidities. As such, the utilization of swine models in early research allows for the evaluation of novel drug and technology efficacy while encouraging redesign and refinement before committing to clinical testing. This review highlights the appropriateness of the miniature swine for modeling complex physiologic systems, presenting it as a highly translational preclinical platform to validate efficacy and safety of therapies and devices.

Large animal models of cardiovascular disease

The human cardiovascular system is a complex arrangement of specialized structures with distinct functions. The molecular landscape, including the genome, transcriptome and proteome, is pivotal to the biological complexity of both normal and abnormal mammalian processes. Despite our advancing knowledge and understanding of cardiovascular disease (CVD) through the principal use of rodent models, this continues to be an increasing issue in today's world. For instance, as the ageing population increases, so does the incidence of heart valve dysfunction. This may be because of changes in molecular composition and structure of the extracellular matrix, or from the pathological process of vascular calcification in which bone-formation related factors cause ectopic mineralization. However, significant differences between mice and men exist in terms of cardiovascular anatomy, physiology and pathology. In contrast, large animal models can show considerably greater similarity to humans. Furthermore, precise and efficient genome editing techniques enable the generation of tailored models for translational research. These novel systems provide a huge potential for large animal models to investigate the regulatory factors and molecular pathways that contribute to CVD in vivo. In turn, this will help bridge the gap between basic science and clinical applications by facilitating the refinement of therapies for cardiovascular disease.

Stimulatory Effects of Coumestrol on Embryonic and Fetal Development Through AKT and ERK1/2 MAPK Signal Transduction

Successful establishment of pregnancy is required for fetal-maternal interactions regulating implantation, embryonic development and placentation. A uterine environment with insufficient growth factors and nutrients increases the incidence of intrauterine growth restriction (IUGR) leading to an impaired uterine environment. In the present study, we demonstrated the effects of the phytoestrogen coumestrol on conceptus development in the pig that is regarded as an excellent biomedical animal model for research on IUGR. Results of this study indicated that coumestrol induced migration of porcine trophectoderm (pTr) cells in a concentration-dependent manner. In response to coumestrol, the phosphorylation of AKT, P70S6K, S6, ERK1/2 MAPK, and P90RSK proteins were activated in pTr cells and ERK1/2 MAPK and P90RSK phosphorylation was prolonged for a longer period than for the other proteins. To identify the signal transduction pathway induced by coumestrol, pharmacological inhibitors U0126 (an ERK1/2 inhibitor) and LY294002 (a PI3K inhibitor) were used to pretreat pTr cells. The results showed that coumestrol-induced phosphorylation of ERK1/2 MAPK and P90RSK was blocked by U0126. In addition, the increased phosphorylation in response to coumestrol was completely inhibited following pre-treatment incubation of pTr cells in the presence of LY294002 and U0126. Furthermore, these two inhibitors suppressed the ability of coumestrol to induce migration of pTr cells. Collectively, these findings suggest that coumestrol affects embryonic development through activation of the PI3K/AKT and ERK1/2 MAPK cell signal transduction pathways and improvement in the uterine environment through coumestrol supplementation may provide beneficial effects of enhancing embryonic and fetal survival and development. J. Cell. Physiol. 231: 2733-2740, 2016. © 2016 Wiley Periodicals, Inc.

Comparison of Immunomodulation Properties of Porcine Mesenchymal Stromal/Stem Cells Derived from the Bone Marrow, Adipose Tissue, and Dermal Skin Tissue

Mesenchymal stromal/stem cells (MSCs) demonstrate immunomodulation capacity that has been implicated in the reduction of graft-versus-host disease. Accordingly, we herein investigated the capacity of MSCs derived from several tissue sources to modulate both proinflammatory (interferon [IFN] γ and tumor necrosis factor [TNF] α) and immunosuppressive cytokines (transforming growth factor [TGF] β and interleukin [IL] 10) employing xenogeneic human MSC-mixed lymphocyte reaction (MLR) test. Bone marrow-derived MSCs showed higher self-renewal capacity with relatively slow proliferation rate in contrast to adipose-derived MSCs which displayed higher proliferation rate. Except for the lipoprotein gene, there were no marked changes in osteogenesis- and adipogenesis-related genes following in vitro differentiation; however, the histological marker analysis revealed that adipose MSCs could be differentiated into both adipose and bone tissue. TGFβ and IL10 were detected in adipose MSCs and bone marrow MSCs, respectively. However, skin-derived MSCs expressed both IFNγ and IL10, which may render them sensitive to immunomodulation. The xenogeneic human MLR test revealed that MSCs had a partial immunomodulation capacity, as proliferation of activated and resting peripheral blood mononuclear cells was not affected, but this did not differ among MSC sources. MSCs were not tumorigenic when introduced into immunodeficient mice. We concluded that the characteristics of MSCs are tissue source-dependent and their in vivo application requires more in-depth investigation regarding their precise immunomodulation capacities.

Genetic engineering of mammals

Historically, genetic engineering for mammalian reproductive questions has been accomplished primarily in the mouse. However, all the genetic manipulations that can be done in the mouse can now be accomplished in most domesticated mammals. Random integration of transgenes, homologous recombination and gene editing are now routine for several mammalian species. For livestock, queries related to fertility can be asked directly for the species in question, without a need for a mouse model. For human clinical concerns, the most appropriate model should be selected based on physiology, anatomy, or even size. The mouse will continue to be a useful genetically engineered model. However, other species are now amenable to the full range of genetic manipulations and should be considered as possible models for human conditions when appropriate.

Animal models to study acute and chronic intestinal inflammation in mammals

Acute and chronic inflammatory diseases of the intestine impart a significant and negative impact on the health and well-being of human and non-human mammalian animals. Understanding the underlying mechanisms of inflammatory disease is mandatory to develop effective treatment and prevention strategies. As inflammatory disease etiologies are multifactorial, the use of appropriate animal models and associated metrics of disease are essential. In this regard, animal models used alone or in combination to study acute and chronic inflammatory disease of the mammalian intestine paired with commonly used inflammation-inducing agents are reviewed. This includes both chemical and biological incitants of inflammation, and both non-mammalian (i.e. nematodes, insects, and fish) and mammalian (i.e. rodents, rabbits, pigs, ruminants, dogs, and non-human primates) models of intestinal inflammation including germ-free, gnotobiotic, as well as surgical, and genetically modified animals. Importantly, chemical and biological incitants induce inflammation via a multitude of mechanisms, and intestinal inflammation and injury can vary greatly according to the incitant and animal model used, allowing studies to ascertain both long-term and short-term effects of inflammation. Thus, researchers and clinicians should be aware of the relative strengths and limitations of the various animal models used to study acute and chronic inflammatory diseases of the mammalian intestine, and the scope and relevance of outcomes achievable based on this knowledge. The ability to induce inflammation to mimic common human diseases is an important factor of a successful animal model, however other mechanisms of disease such as the amount of infective agent to induce disease, invasion mechanisms, and the effect various physiologic changes can have on inducing damage are also important features. In many cases, the use of multiple animal models in combination with both chemical and biological incitants is necessary to answer the specific question being addressed regarding intestinal disease. Some incitants can induce acute responses in certain animal models while others can be used to induce chronic responses; this review aims to illustrate the strengths and weaknesses in each animal model and to guide the choice of an appropriate acute or chronic incitant to facilitate intestinal disease.