The transcriptomic landscape of neurons carrying PSEN1 mutations reveals changes in extracellular matrix components and non-coding gene expression

Alzheimer's disease (AD) is a progressive and irreversible brain disorder, which can occur either sporadically, due to a complex combination of environmental, genetic, and epigenetic factors, or because of rare genetic variants in specific genes (familial AD, or fAD). A key hallmark of AD is the accumulation of amyloid beta (Aβ) and Tau hyperphosphorylated tangles in the brain, but the underlying pathomechanisms and interdependencies remain poorly understood. Here, we identify and characterise gene expression changes related to two fAD mutations (A79V and L150P) in the Presenilin-1 (PSEN1) gene. We do this by comparing the transcriptomes of glutamatergic forebrain neurons derived from fAD-mutant human induced pluripotent stem cells (hiPSCs) and their individual isogenic controls generated via precision CRISPR/Cas9 genome editing. Our analysis of Poly(A) RNA-seq data detects 1111 differentially expressed coding and non-coding genes significantly altered in fAD. Functional characterisation and pathway analysis of these genes reveal profound expression changes in constituents of the extracellular matrix, important to maintain the morphology, structural integrity, and plasticity of neurons, and in genes involved in calcium homeostasis and mitochondrial oxidative stress. Furthermore, by analysing total RNA-seq data we reveal that 30 out of 31 differentially expressed circular RNA genes are significantly upregulated in the fAD lines, and that these may contribute to the observed protein-coding gene expression changes. The results presented in this study contribute to a better understanding of the cellular mechanisms impacted in AD neurons, ultimately leading to neuronal damage and death.

Golgi fragmentation - One of the earliest organelle phenotypes in Alzheimer's disease neurons

Alzheimer's disease (AD) is the most common cause of dementia, with no current cure. Consequently, alternative approaches focusing on early pathological events in specific neuronal populations, besides targeting the well-studied amyloid beta (Aβ) accumulations and Tau tangles, are needed. In this study, we have investigated disease phenotypes specific to glutamatergic forebrain neurons and mapped the timeline of their occurrence, by implementing familial and sporadic human induced pluripotent stem cell models as well as the 5xFAD mouse model. We recapitulated characteristic late AD phenotypes, such as increased Aβ secretion and Tau hyperphosphorylation, as well as previously well documented mitochondrial and synaptic deficits. Intriguingly, we identified Golgi fragmentation as one of the earliest AD phenotypes, indicating potential impairments in protein processing and post-translational modifications. Computational analysis of RNA sequencing data revealed differentially expressed genes involved in glycosylation and glycan patterns, whilst total glycan profiling revealed minor glycosylation differences. This indicates general robustness of glycosylation besides the observed fragmented morphology. Importantly, we identified that genetic variants in Sortilin-related receptor 1 (SORL1) associated with AD could aggravate the Golgi fragmentation and subsequent glycosylation changes. In summary, we identified Golgi fragmentation as one of the earliest disease phenotypes in AD neurons in various in vivo and in vitro complementary disease models, which can be exacerbated via additional risk variants in SORL1.

Production of human entorhinal stellate cell-like cells by forward programming shows an important role of Foxp1 in reprogramming

Stellate cells are principal neurons in the entorhinal cortex that contribute to spatial processing. They also play a role in the context of Alzheimer's disease as they accumulate Amyloid beta early in the disease. Producing human stellate cells from pluripotent stem cells would allow researchers to study early mechanisms of Alzheimer's disease, however, no protocols currently exist for producing such cells. In order to develop novel stem cell protocols, we characterize at high resolution the development of the porcine medial entorhinal cortex by tracing neuronal and glial subtypes from mid-gestation to the adult brain to identify the transcriptomic profile of progenitor and adult stellate cells. Importantly, we could confirm the robustness of our data by extracting developmental factors from the identified intermediate stellate cell cluster and implemented these factors to generate putative intermediate stellate cells from human induced pluripotent stem cells. Six transcription factors identified from the stellate cell cluster including RUNX1T1, SOX5, FOXP1, MEF2C, TCF4, EYA2 were overexpressed using a forward programming approach to produce neurons expressing a unique combination of RELN, SATB2, LEF1 and BCL11B observed in stellate cells. Further analyses of the individual transcription factors led to the discovery that FOXP1 is critical in the reprogramming process and omission of RUNX1T1 and EYA2 enhances neuron conversion. Our findings contribute not only to the profiling of cell types within the developing and adult brain's medial entorhinal cortex but also provides proof-of-concept for using scRNAseq data to produce entorhinal intermediate stellate cells from human pluripotent stem cells in-vitro.

In vitro and in vivo-produced male dairy calves show molecular differences in the hepatic and muscular energy regulation

In cattle, the in vitro production (IVP) of embryos is becoming more relevant than embryos produced in vivo, i.e. after multiple ovulation and embryo transfer (MOET). However, the effects of IVP on the developmental programming of specific organs in the postnatal calves are yet unknown. Previously, we reported an epigenomic and transcriptomic profile of the hypothalamus–pituitary–testicular axis compatible with its earlier activation in IVP calves compared to MOET animals. Here, we studied the hepatic and muscular epigenome and transcriptome of those same male dairy calves (n = 4 per group). Tissue samples from liver and semitendinosus muscle were obtained at 3 months of age, and the extracted gDNA and RNA were sequenced through whole-genome bisulfite sequencing and RNA-sequencing, respectively. Next, bioinformatic analyses determined differentially methylated cytosines or differentially expressed genes [false discovery rate (FDR) < 0.05] for each Omic dataset; and nonparametrically combined genes (NPCG) for both integrated omics (P < 0.05). KEGG pathways enrichment analysis showed that NPCG upregulated in the liver and the muscle of the IVP calves were involved in oxidative phosphorylation and the tricarboxylic acid cycle. In contrast, ribosome and translation were upregulated in the liver but downregulated in the muscle of the IVP calves compared to the MOET calves (FDR < 0.05). A model considering the effect of the methylation levels and the group on the expression of all the genes involved in these pathways confirmed these findings. In conclusion, the multiomics data integration approach indicated an altered hepatic and muscular energy regulation in phenotypically normal IVP calves compared to MOET calves.

Neural Derivates of Canine Induced Pluripotent Stem Cells-Like Cells From a Mild Cognitive Impairment Dog

Domestic dogs are superior models for translational medicine due to greater anatomical and physiological similarities with humans than rodents, including hereditary diseases with human equivalents. Particularly with respect to neurodegenerative medicine, dogs can serve as a natural, more relevant model of human disease compared to transgenic rodents. Herein we report attempts to develop a canine-derived in vitro model for neurodegenerative diseases through the generation of induced pluripotent stem cells from a 14-year, 9-month-old female West Highland white terrier with mild cognitive impairment (MCI). Canine induced pluripotent stem cells-like cells (ciPSCLC) were generated using human OSKM and characterized by positive expression of pluripotency markers. Due to inefficient viral vector silencing we refer to them as ciPSCLCs. Subsequently, the ciPSCLC were subjected to neural induction according to two protocols both yielding canine neural progenitor cells (cNPCs), which expressed typical NPC markers. The cNPCs were cultured in neuron differentiation media for 3 weeks, resulting in the derivation of morphologically impaired neurons as compared to iPSC-derived human counterparts generated in parallel. The apparent differences encountered in this study regarding the neural differentiation potential of ciPSCLC reveals challenges and new perspectives to consider before using the canine model in translational neurological studies.

Astrocytic reactivity triggered by defective autophagy and metabolic failure causes neurotoxicity in frontotemporal dementia type 3

Frontotemporal dementia type 3 (FTD3), caused by a point mutation in the charged multivesicular body protein 2B (CHMP2B), affects mitochondrial ultrastructure and the endolysosomal pathway in neurons. To dissect the astrocyte-specific impact of mutant CHMP2B expression, we generated astrocytes from human induced pluripotent stem cells (hiPSCs) and confirmed our findings in CHMP2B mutant mice. Our data provide mechanistic insights into how defective autophagy causes perturbed mitochondrial dynamics with impaired glycolysis, increased reactive oxygen species, and elongated mitochondrial morphology, indicating increased mitochondrial fusion in FTD3 astrocytes. This shift in astrocyte homeostasis triggers a reactive astrocyte phenotype and increased release of toxic cytokines, which accumulate in nuclear factor kappa b (NF-κB) pathway activation with increased production of CHF, LCN2, and C3 causing neurodegeneration.

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FTD3 iPSC-derived astrocytes display impaired autophagy

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Impaired autophagy affects mitochondria turnover, glucose hypometabolism and TCA cycle

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FTD3 astrocytes contribute to reactive gliosis by increased C3, LCN2, IL6, and IL8

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Reactive astrocyte phenotypes are present in both in vitro and in vivo models

Epigenomic and transcriptomic analyses reveal early activation of the HPG axis in in vitro-produced male dairy calves

In cattle, several calves born after IVP ("in vitro" embryo production) present similar birthweight to those generated after MOET (multiple ovulation and embryo transfer). However, the underlying molecular patterns in organs involved in the developmental process are unknown and could indicate physiological programming. The objectives of this study were: (1) to compare epigenomic and transcriptomic modifications in the hypothalamus, pituitary, gonadal and adrenal organs between 3 months old ovum pick-up-IVP and MOET male calves (n = 4 per group) and (2) to use blood epigenomic data to proxy methylation of the inner organs. Extracted gDNA and RNA were sequenced through whole-genome bisulfite sequencing and RNA sequencing, respectively. Next, bioinformatic analyses determined differentially methylated cytosines (DMC) and differentially expressed genes (DEG) (FDR < 0.05) in IVP versus MOET samples and the KEGG pathways that were overrepresented by genes associated with DMC or DEG (FDR < 0.1). Pathways related to hypothalamus, pituitary, gonadal (HPG) axis activation (GnRH secretion in the hypothalamus, GnRH signaling in the pituitary, and steroidogenesis in the testicle) were enriched in IVP calves. Modeling the effect of the methylation levels and the group on the expression of all the genes involved in these pathways confirmed their upregulation in HPG organs in IVP calves. The application of the DIABLO method allowed the identification of 15 epigenetic and five transcriptomic biomarkers, which were able to predict the embryo origin using the epigenomic data from the blood. In conclusion, the use of an integrated epigenomic-transcriptomic approach suggested an early activation of the HPG axis in male IVP calves compared to MOET counterparts, and the identification of potential biomarkers allowed the use of blood samples to proxy methylation levels of the relevant internal organs.

Identification of bioactive metabolites in human iPSC-derived dopaminergic neurons with PARK2 mutation: Altered mitochondrial and energy metabolism

PARK2 (parkin) mutations cause early-onset Parkinson's disease (PD). Parkin is an ubiquitin E3 ligase that participates in several cellular functions, including mitochondrial homeostasis. However, the specific metabolomic changes caused by parkin depletion remain unknown. Here, we used isogenic human induced pluripotent stem cells (iPSCs) with and without PARK2 knockout (KO) to investigate the effect of parkin loss of function by comparative metabolomics supplemented with ultrastructural and functional analyses. PARK2 KO neurons displayed increased tricarboxylic acid (TCA) cycle activity, perturbed mitochondrial ultrastructure, ATP depletion, and dysregulation of glycolysis and carnitine metabolism. These perturbations were combined with increased oxidative stress and a decreased anti-oxidative response. Key findings for PARK2 KO cells were confirmed using patient-specific iPSC-derived neurons. Overall, our data describe a unique metabolomic profile associated with parkin dysfunction and show that combining metabolomics with an iPSC-derived dopaminergic neuronal model of PD is a valuable approach to obtain novel insight into the disease pathogenesis.

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PARK2 (parkin) mutations cause metabolic dysregulation

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Parkin dysfunction causes increased TCA cycle activity and ATP depletion

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Parkin affects glycolysis and carnitine metabolism

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Parkin-related energy perturbations are combined with increased oxidative stress

Application of multi-omics data integration and machine learning approaches to identify epigenetic and transcriptomic differences between in vitro and in vivo produced bovine embryos

Pregnancy rates for in vitro produced (IVP) embryos are usually lower than for embryos produced in vivo after ovarian superovulation (MOET). This is potentially due to alterations in their trophectoderm (TE), the outermost layer in physical contact with the maternal endometrium. The main objective was to apply a multi-omics data integration approach to identify both temporally differentially expressed and differentially methylated genes (DEG and DMG), between IVP and MOET embryos, that could impact TE function. To start, four and five published transcriptomic and epigenomic datasets, respectively, were processed for data integration. Second, DEG from day 7 to days 13 and 16 and DMG from day 7 to day 17 were determined in the TE from IVP vs. MOET embryos. Third, genes that were both DE and DM were subjected to hierarchical clustering and functional enrichment analysis. Finally, findings were validated through a machine learning approach with two additional datasets from day 15 embryos. There were 1535 DEG and 6360 DMG, with 490 overlapped genes, whose expression profiles at days 13 and 16 resulted in three main clusters. Cluster 1 (188) and Cluster 2 (191) genes were down-regulated at day 13 or day 16, respectively, while Cluster 3 genes (111) were up-regulated at both days, in IVP embryos compared to MOET embryos. The top enriched terms were the KEGG pathway "focal adhesion" in Cluster 1 (FDR = 0.003), and the cellular component: "extracellular exosome" in Cluster 2 (FDR<0.0001), also enriched in Cluster 1 (FDR = 0.04). According to the machine learning approach, genes in Cluster 1 showed a similar expression pattern between IVP and less developed (short) MOET conceptuses; and between MOET and DKK1-treated (advanced) IVP conceptuses. In conclusion, these results suggest that early conceptuses derived from IVP embryos exhibit epigenomic and transcriptomic changes that later affect its elongation and focal adhesion, impairing post-transfer survival.

Development of the Entorhinal Cortex Occurs via Parallel Lamination During Neurogenesis

The entorhinal cortex (EC) is the spatial processing center of the brain and structurally is an interface between the three layered paleocortex and six layered neocortex, known as the periarchicortex. Limited studies indicate peculiarities in the formation of the EC such as early emergence of cells in layers (L) II and late deposition of LIII, as well as divergence in the timing of maturation of cell types in the superficial layers. In this study, we examine developmental events in the entorhinal cortex using an understudied model in neuroanatomy and development, the pig and supplement the research with BrdU labeling in the developing mouse EC. We determine the pig serves as an excellent anatomical model for studying human neurogenesis, given its long gestational length, presence of a moderate sized outer subventricular zone and early cessation of neurogenesis during gestation. Immunohistochemistry identified prominent clusters of OLIG2+ oligoprogenitor-like cells in the superficial layers of the lateral EC (LEC) that are sparser in the medial EC (MEC). These are first detected in the subplate during the early second trimester. MRI analyses reveal an acceleration of EC growth at the end of the second trimester. BrdU labeling of the developing MEC, shows the deeper layers form first and prior to the superficial layers, but the LV/VI emerges in parallel and the LII/III emerges later, but also in parallel. We coin this lamination pattern parallel lamination. The early born Reln+ stellate cells in the superficial layers express the classic LV marker, Bcl11b (Ctip2) and arise from a common progenitor that forms the late deep layer LV neurons. In summary, we characterize the developing EC in a novel animal model and outline in detail the formation of the EC. We further provide insight into how the periarchicortex forms in the brain, which differs remarkably to the inside-out lamination of the neocortex.

78 Effects of invitro production on the epigenome and transcriptome of bovine embryos determined through a multi-omics data integration approach

In cattle, ovarian superovulation followed by invivo embryo collection and transfer (MOET), and the invitro production (IVP) of embryos are used all over the world to improve animal genetics. Application of MOET has resulted in the production of billions of healthy animals during the past 40 years, and IVP has evolved and given rise to significant numbers of calves during the past 10 years. Nevertheless, the use of MOET and IVP can affect the embryo epigenome, and therefore its transcriptome, before and after elongation, as shown by different studies. The integration of publicly available epigenome-transcriptome datasets generated by these studies could lead to a robust characterisation of the impacts of the application of MOET and IVP. The goal of this study was to integrate all publicly available data about MOET and IVP embryos to determine temporally differentially methylated regions (DMRs) and differentially expressed genes (DEGs) from blastocyst to elongation between IVP and MOET embryos. Datasets were downloaded from the Gene Expression Omnibus (GEO) database. Accession numbers were (1) for epigenomics: GSE69173, GSE97517, and GSE101895, plus one provided dataset from O’Doherty et al. (2018 BMC Genomics, 19, 438; https://doi.org/10.1186/s12864-018-4818-3), all hybridized to the EDMA platform GPL18384; (2) for transcriptomics: GSE12327, GSE21030, GSE24596, GSE24936, GSE27817, and GSE40101, all hybridized to the Affymetrix platform GPL2112. Both types of data were analysed with the limma package for R software, and functional enrichment analysis was done with the DAVID database. For DMRs, comparisons between IVP and MOET were made from spherical blastocysts (n=16 per group) on Day 7, to embryos on Day 15, specifically in the trophectoderm (TE) or embryonic disc (ED) regions (n=4 per region and per group). For DEGs, comparisons between IVP and MOET were made from spherical blastocysts (n=9 per group) to elongated blastocysts on Day 13 and embryos undergoing gastrulation on Day 16 (n=6 per group). Considering a P-value &lt;0.05 and fold-change &gt;2, there were 16 672 (TE) and 26 264 (ED) DMRs and 2236 DEGs that temporally differed between IVP and MOET. Most of the identified DMRs were found in intronic regions (around 36%) rather than exonic regions (8%). However, DMRs that were more methylated at IVP compared with MOET contained exons encoding for genes that enriched the Wnt signalling Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway in the ED, and focal adhesion and ECM-receptor interaction KEGG pathways (P&lt;0.05) in the TE. Accordingly, DEGs with lower expression in elongated embryos (Day 13 and Day 16) at IVP as opposed to MOET were mainly associated with these three pathways. In conclusion, this multi-omics analysis demonstrates that even when embryos are produced under different conditions and experiments, the main changes imposed by IVP affected genes involved in embryonic development and adhesion to the endometrium, which could explain the lower survival rates at IVP compared with MOET.

23 Biopsied invitro-produced bovine blastocysts survive vitrification better than slow freezing

Trophectoderm (TE) biopsying for single nucleotide polymorphisms (SNPs) analysis is being implemented as a tool for the selection of elite bovine embryos. This biopsy method renders ample cells for analysis without compromising the inner cell mass (ICM), and the blastocyst recovers quickly after biopsy. To use the SNP data for embryo selection before the transfer, the blastocysts need to be cryopreserved either with vitrification or slow-freezing. In intact invitro-produced (IVP) blastocysts, vitrification has already proven optimal regarding embryo survival and pregnancy rates. This study aimed to investigate which cryopreservation approach is superior regarding blastocyst re-expansion rate as well as ICM, TE, and dead cell numbers after biopsying bovine IVP blastocysts. All IVP media and vitrification kits were from IVF Bioscience, and ethylene glycol with sucrose was from EggTech. Oocytes from slaughterhouse ovaries were used for blastocyst IVP. At Day 7, the blastocysts were pooled and randomised into 3 groups: (1) biopsy-control (BC), (2) biopsy-vitrification (BV), (3) biopsy-slow freeze (BSF). Subsequently, 5 to 10 TE cells were biopsied in BO-transfer medium using a 25-µm (inner diameter) biopsy pipette and flicking against the holding pipette. The BC group was incubated at 6% CO2 and 38.8°C for 5h. After scoring the re-expansion rate, the blastocysts were fixed with 4% paraformaldehyde/sucrose for further analyses. The BV and BSF groups were subjected to cryopreservation/thawing protocols according to the manufacturers’ instructions. Both groups, recovered under the same culture conditions as BC, were subsequently scored for re-expansion rate and finally fixed. For cell counting, the embryos were stained with Hoechst (DNA) and CDX2 (TE), combined with the TUNEL staining. ImageJ software (National Institutes for Health) was used for cell counting. P&lt;0.05 was considered statistically significant and was determined using Fisher’s exact test for blastocyst re-expansion rate and Student’s t-test for cell numbers. The re-expansion rate in BV was 81% (61/75), which was significantly lower than in BC (95%; 225/236; P&lt;0.005). In BSF, the re-expansion rate was 52% (28/54), which was significantly lower than in both BV and BC (both P&lt;0.005). For cell counts, 18, 18, and 14 embryos, pooled from 3 to 4 independent IVP replicates, were analysed in BC, BV, and BSF, respectively. The average numbers of ICM cells in BV and BSF were 36±5 and 37±11, respectively, and neither was statistically different from BC (34±7; P&gt;0.05). The average cell counts for TE cells in BV and BSF were 59±6 and 47±10, respectively, and neither was statistically different from BC (56±8; P&gt;0.05). The average numbers of dead cells in BV and BSF were 8±3 and 9±2, respectively, and neither was statistically different from BC (10±4; P&gt;0.05). In summary, the biopsied bovine IVP blastocysts recovered better after vitrification, and neither of cryopreservation methods had any effect on the numbers of ICM, TE, or dead cells. This project was supported by Innovation Fund Denmark and the Danish Milk Levy Foundation.

Enrichment of retinal ganglion and Müller glia progenitors from retinal organoids derived from human induced pluripotent stem cells - possibilities and current limitations

BACKGROUND

Retinal organoids serve as excellent human-specific disease models for conditions affecting otherwise inaccessible retinal tissue from patients. They permit the isolation of key cell types affected in various eye diseases including retinal ganglion cells (RGCs) and Müller glia.

AIM

To refine human-induced pluripotent stem cells (hiPSCs) differentiated into three-dimensional (3D) retinal organoids to generate sufficient numbers of RGCs and Müller glia progenitors for downstream analyses.

METHODS

In this study we described, evaluated, and refined methods with which to generate Müller glia and RGC progenitors, isolated them via magnetic-activated cell sorting, and assessed their lineage stability after prolonged 2D culture. Putative progenitor populations were characterized via quantitative PCR and immunocytochemistry, and the ultrastructural composition of retinal organoid cells was investigated.

RESULTS

Our study confirms the feasibility of generating marker-characterized Müller glia and RGC progenitors within retinal organoids. Such retinal organoids can be dissociated and the Müller glia and RGC progenitor-like cells isolated via magnetic-activated cell sorting and propagated as monolayers.

CONCLUSION

Enrichment of Müller glia and RGC progenitors from retinal organoids is a feasible method with which to study cell type-specific disease phenotypes and to potentially generate specific retinal populations for cell replacement therapies.

Bovine in-vitro produced embryos: Development of embryo proper and associated membranes from day 26 to 47 of gestation

Based on in-vitro produced (IVP) bovine embryos, embryo proper and embryonic/fetal membranes were studied in 12 pregnancies from day 26 to 47. The embryos/fetuses displayed external as well as internal development of organs and structures according to the expectations from comparable in-vivo studies. However, the embryonic/fetal membranes were shorter than those reported for in-vivo-derived embryos/fetuses on days 26-35 of calculated age, whereas on days 41-47 they were of comparable lengths.

Human induced pluripotent stem cells (BIONi010-C) generate tight cell monolayers with blood-brain barrier traits and functional expression of large neutral amino acid transporter 1 (SLC7A5)

The barrier properties of the brain capillary endothelium, the blood-brain barrier (BBB) restricts uptake of most small and all large molecule drug compounds to the CNS. There is a need for predictive human in vitro models of the BBB to enable studies of brain drug delivery. Here, we investigated whether human induced pluripotent stem cell (hiPSC) line (BIONi010-C) could be differentiated to brain capillary endothelial- like cells (BCEC) and evaluated their potential use in drug delivery studies. BIONi010-C hIPSCs were differentiated according to established protocols. BCEC monolayers displayed transendothelial electrical resistance (TEER) values of 5,829±354 Ω∙cm², a P_app,_mannitol of 1.09±0.15 ∙ 10^-6 cm∙s^-1 and a P_app,diazepam of 85.7 ± 5.9 ∙ 10^-6 cm ∙s^-1. The P_diazepam/P_mannitol ratio of ~80, indicated a large dynamic passive permeability range. Monolayers maintained their integrity after medium exchange. Claudin-5, Occludin, Zonulae Occludens 1 and VE-Cadherin were expressed at the cell-cell contact zones. Efflux transporters were present at the mRNA level, but functional efflux of substrates was not detected. Transferrin-receptor (TFR), Low density lipoprotein receptor-related protein 1 (LRP1) and Basigin receptors were expressed at the mRNA-level. The presence and localization of TFR and LRP1 were verified at the protein level. A wide range of BBB-expressed solute carriers (SLC's) were detected at the mRNA level. The presence and localization of SLC transporters GLUT1 and LAT1 was verified at the protein level. Functional studies revealed transport of the LAT1 substrate [³H]-L-Leucine and the LRP1 substrate angiopep-2. In conclusion, we have demonstrated that BIONi010-C-derived BCEC monolayers exhibited, BBB properties including barrier tightness and integrity, a high dynamic range, expression of some of the BBB receptor and transporter expression, as well as functional transport of LAT1 and LRP1 substrates. This suggests that BIONi010-C-derived BCEC monolayers may be useful for studying the roles of LAT-1 and LRP1 in brain drug delivery.

Characterization of the endometrial transcriptome in early diestrus influencing pregnancy status in dairy cattle after transfer of in vitro-produced embryos

Modifications of the endometrial transcriptome at day 7 of the estrus cycle are crucial to maintain gestation after transfer of in vitro-produced (IVP) embryos, although these changes are still largely unknown. The aim of this study was to identify genes, and their related biological mechanisms, important for pregnancy establishment based on the endometrial transcriptome of recipient lactating dairy cows that become pregnant in the subsequent estrus cycle, upon transfer of IVP embryos. Endometrial biopsies were taken from Holstein Friesian cows on day 6-8 of the estrus cycle followed by embryo transfer in the following cycle. Animals were classified retrospectively as pregnant (PR, n = 8) or nonpregnant (non-PR, n = 11) cows, according to pregnancy status at 26-47 days. Extracted mRNAs from endometrial samples were sequenced with an Illumina platform to determine differentially expressed genes (DEG) between the endometrial transcriptome from PR and non-PR cows. There were 111 DEG (false discovery rate < 0.05), which were mainly related to extracellular matrix interaction, histotroph metabolic composition, prostaglandin synthesis, transforming growth factor-β signaling as well as inflammation and leukocyte activation. Comparison of these DEG with DEG identified in two public external data sets confirmed the more fertile endometrial molecular profile of PR cows. In conclusion, this study provides insights into the key early endometrial mechanisms for pregnancy establishment, after IVP embryo transfer in dairy cows.

Cellular alterations identified in pluripotent stem cell-derived midbrain spheroids generated from a female patient with progressive external ophthalmoplegia and parkinsonism who carries a novel variation (p.Q811R) in the POLG1 gene

Variations in the POLG1 gene encoding the catalytic subunit of the mitochondrial DNA polymerase gamma, have recently been associated with Parkinson's disease (PD), especially in patients diagnosed with progressive external ophthalmoplegia (PEO). However, the majority of the studies reporting this association mainly focused on the genetic identification of the variation in POLG1 in PD patient primary cells, and determination of mitochondrial DNA copy number, providing little information about the cellular alterations existing in patient brain cells, in particular dopaminergic neurons. Therefore, through the use of induced pluripotent stem cells (iPSCs), we assessed cellular alterations in novel p.Q811R POLG1 (POLG1^Q811R) variant midbrain dopaminergic neuron-containing spheroids (MDNS) from a female patient who developed early-onset PD, and compared them to cultures derived from a healthy control of the same gender. Both POLG1 variant and control MDNS contained functional midbrain regionalized TH/FOXA2-positive dopaminergic neurons, capable of releasing dopamine. Western blot analysis identified the presence of high molecular weight oligomeric alpha-synuclein in POLG1^Q811R MDNS compared to control cultures. In order to assess POLG1^Q811R-related cellular alterations within the MDNS, we applied mass-spectrometry based quantitative proteomic analysis. In total, 6749 proteins were identified, with 61 significantly differentially expressed between POLG1^Q811R and control samples. Pro- and anti-inflammatory signaling and pathways involved in energy metabolism were altered. Notably, increased glycolysis in POLG1^Q811R MDNS was suggested by the increase in PFKM and LDHA levels and confirmed using functional analysis of glycolytic rate and oxygen consumption levels. Our results validate the use of iPSCs to assess cellular alterations in relation to PD pathogenesis, in a unique PD patient carrying a novel p.Q811R variation in POLG1, and identify several altered pathways that may be relevant to PD pathogenesis.

Genetic Protection Modifications: Moving Beyond the Binary Distinction Between Therapy and Enhancement for Human Genome Editing

The current debate and policy surrounding the use of genome editing in humans typically relies on a binary distinction between therapy and human enhancement. Here, we argue that this dichotomy fails to take into account perhaps the most significant potential uses of CRISPR-Cas9 genome editing in humans. We argue that genetic treatment of sporadic Alzheimer's disease, breast and ovarian cancer predisposing BRCA1/2 mutations, and the introduction of human immunodeficiency virus resistance in humans should be considered within a new category of genetic protection treatments. We suggest that if this category is not introduced, life-altering research might be unnecessarily limited by current or future policy. Otherwise ad hoc decisions might be made, which introduce a risk of unforeseen moral costs, and might overlook or fail to address some important opportunities.

Alpha7 nicotinic acetylcholine receptors and neural network synaptic transmission in human induced pluripotent stem cell-derived neurons

The α7 nicotinic acetylcholine receptor has been extensively researched as a target for treatment of cognitive impairment in Alzheimer's disease and schizophrenia. Investigation of the α7 receptor is commonly performed in animals but it is critical to increase the biologically relevance of the model systems to fully capture the physiological role of the α7 receptor in humans. For example most humans, in contrast to animals, express the hybrid gene CHRFAM7A, the product of which modulates α7 receptor activity. In the present study, we used human induced pluripotent stem cell (hiPSC) derived neurons to establish a humanized α7 model. We established a cryobank of neural stem cells (NSCs) that could reproducibly be matured into neurons expressing neuronal markers and CHRNA7 and CHRFAM7A. The neurons responded to NMDA, GABA, and acetylcholine and exhibited synchronized spontaneous calcium oscillations. Gene expression studies and application of a range of α7 positive allosteric modulators (PNU-120595, TQS, JNJ-39393406 and AF58801) together with the α7 agonist PNU-282987 during measurement of intracellular calcium levels demonstrated the presence of functional α7 receptors in matured hiPSC-derived neuronal cultures. Pharmacological α7 activation also resulted in intracellular signaling as measured by ERK 1/2 phosphorylation and c-Fos protein expression. Moreover, PNU-120596 increased the frequency of the spontaneous calcium oscillations demonstrating implication of α7 receptors in human synaptic networks activity. Overall, we show that hiPSC derived neurons are an advanced in vitro model for studying human α7 receptor pharmacology and the involvement of this receptor in cellular processes as intracellular signaling and synaptic transmission.

Oocytes, embryos and pluripotent stem cells from a biomedical perspective

The veterinary and animal science professions are rapidly developing and their inherent and historical connection to agriculture is challenged by more biomedical and medical directions of research. While some consider this development as a risk of losing identity, it may also be seen as an opportunity for developing further and more sophisticated competences that may ultimately feed back to veterinary and animal science in a synergistic way. The present review describes how agriculture-related studies on bovine in vitro embryo production through studies of putative bovine and porcine embryonic stem cells led the way to more sophisticated studies of human induced pluripotent stem cells (iPSCs) using e.g. gene editing for modeling of neurodegeneration in man. However, instead of being a blind diversion from veterinary and animal science into medicine, these advanced studies of human iPSC-derived neurons build a set of competences that allowed us, in a more competent way, to focus on novel aspects of more veterinary and agricultural relevance in the form of porcine and canine iPSCs. These types of animal stem cells are of biomedical importance for modeling of iPSC-based therapy in man, but in particular the canine iPSCs are also important for understanding and modeling canine diseases, as e.g. canine cognitive dysfunction, for the benefit and therapy of dogs.

Modelling the neuropathology of lysosomal storage disorders through disease-specific human induced pluripotent stem cells

Mucopolysaccharidosis II (MPS II) is a lysosomal storage disorder (LSD), caused by iduronate 2-sulphatase (IDS) enzyme dysfunction. The neuropathology of the disease is not well understood, although the neural symptoms are currently incurable. MPS II-patient derived iPSC lines were established and differentiated to neuronal lineage. The disease phenotype was confirmed by IDS enzyme and glycosaminoglycan assay. MPS II neuronal precursor cells (NPCs) showed significantly decreased self-renewal capacity, while their cortical neuronal differentiation potential was not affected. Major structural alterations in the ER and Golgi complex, accumulation of storage vacuoles, and increased apoptosis were observed both at protein expression and ultrastructural level in the MPS II neuronal cells, which was more pronounced in GFAP + astrocytes, with increased LAMP2 expression but unchanged in their RAB7 compartment. Based on these finding we hypothesize that lysosomal membrane protein (LMP) carrier vesicles have an initiating role in the formation of storage vacuoles leading to impaired lysosomal function. In conclusion, a novel human MPS II disease model was established for the first time which recapitulates the in vitro neuropathology of the disorder, providing novel information on the disease mechanism which allows better understanding of further lysosomal storage disorders and facilitates drug testing and gene therapy approaches.

Evidence for nucleolar dysfunction in Alzheimer's disease

The nucleolus is a dynamically changing organelle that is central to a number of important cellular functions. Not only is it important for ribosome biogenesis, but it also reacts to stress by instigating a nucleolar stress response and is further involved in regulating the cell cycle. Several studies report nucleolar dysfunction in Alzheimer's disease (AD). Studies have reported a decrease in both total nucleolar volume and transcriptional activity of the nucleolar organizing regions. Ribosomes appear to be targeted by oxidation and reduced protein translation has been reported. In addition, several nucleolar proteins are dysregulated and some of these appear to be implicated in classical AD pathology. Some studies also suggest that the nucleolar stress response may be activated in AD, albeit this latter research is rather limited and requires further investigation. The purpose of this review is to draw the connections of all these studies together and signify that there are clear changes in the nucleolus and the ribosomes in AD. The nucleolus is therefore an organelle that requires more attention than previously given in relation to understanding the biological mechanisms underlying the disease.

Stem cells on regenerative and reproductive science in domestic animals

Stem cells are undifferentiated and self-renewable cells that present new possibilities for both regenerative medicine and the understanding of early mammalian development. Adult multipotent stem cells are already widely used worldwide in human and veterinary medicine, and their therapeutic signalling, particularly with respect to immunomodulation, and their trophic properties have been intensively studied. The derivation of embryonic stem cells (ESCs) from domestic species, however, has been challenging, and the poor results do not reflect the successes obtained in mouse and human experiments. More recently, the generation of induced pluripotent stem cells (iPSCs) via the forced expression of specific transcription factors has been demonstrated in domestic species and has introduced new potentials in regenerative medicine and reproductive science based upon the ability of these cells to differentiate into a variety of cells types in vitro. For example, iPSCs have been differentiated into primordial germ-like cells (PGC-like cells, PGCLs) and functional gametes in mice. The possibility of using iPSCs from domestic species for this purpose would contribute significantly to reproductive technologies, offering unprecedented opportunities to restore fertility, to preserve endangered species and to generate transgenic animals for biomedical applications. Therefore, this review aims to provide an updated overview of adult multipotent stem cells and to discuss new possibilities introduced by the generation of iPSCs in domestic animals, highlighting the possibility of generating gametes in vitro via PGCL induction.

Generation of transgene-free porcine intermediate type induced pluripotent stem cells

Physiologically and anatomically, humans and pigs share many similarities, which make porcine induced pluripotent stem cells (piPSCs) very attractive for modeling human cell therapy as well as for testing safety of iPSC based cell replacement therapies. To date, several integrative and non-integrative strategies have been reported to successfully generate piPSCs, but all resulting piPSCs had integration of transgenes. The use of integrative methods has the disadvantage of potential lack of silencing or inappropriate re-activation of these genes during differentiation, as well as uncertainty regarding disruption of important genomic regions caused by integration. In our study, we performed a non-integrative vector based reprogramming approach using porcine fetal fibroblasts. The resulting four piPSC lines were positive for pluripotency marker and when subjected to in vitro and in vivo differentiation assays, all four lines formed embryoid bodies, capable to differentiate into all three germ layers, and three out of the four cell lines formed teratomas. PCR analysis on genomic and plasmid DNA revealed that the episomal vectors were undetectable in six out of eight subclones derived from one of the piPSC lines (piPSC1) above passage 20. These piPSCs could potentially be ideal cell lines for the generation of porcine in vitro and in vivo models. Furthermore, subsequent analyses of our new transgene independent piPSCs could provide novel insights on the genetic and epigenetic necessities to achieve and maintain piPSCs.

Simulated physiological oocyte maturation has side effects on bovine oocytes and embryos

PURPOSE

Oocyte maturation is a complex process involving nuclear and cytoplasmic modulations, during which oocytes acquire their ability to become fertilized and support embryonic development. The oocyte is apparently "primed" for maturation during its development in the dominant follicle. As bovine oocytes immediately resume meiosis when cultured, it was hypothesized that delaying resumption of meiosis with cyclic nucleotide modulators before in vitro maturation (IVM) would allow the oocytes to acquire improved developmental competence.

METHODS

We tested the Simulated Physiological Oocyte Maturation (SPOM) system that uses forskolin and 3-isobutyl-1-methylxanthine for 2 h prior to IVM against two different systems of conventional IVM (Con-IVM). We evaluated the ultrastructure of matured oocytes and blastocysts and also assessed the expression of 96 genes related to embryo quality in the blastocysts.

RESULTS

In summary, the SPOM system resulted in lower blastocyst rates than both Con-IVM systems (30 ± 9.1 vs. 35 ± 8.7; 29 ± 2.6 vs. 38 ± 2.8). Mature SPOM oocytes had significantly increased volume and number of vesicles, reduced volume and surface density of large smooth endoplasmic reticulum clusters, and lower number of mitochondria than Con-IVM oocytes. SPOM blastocysts showed only subtle differences with parallel undulations of adjacent trophectoderm plasma membranes and peripherally localized ribosomes in cells of the inner cell mass compared with Con-IVM blastocysts. SPOM blastocysts, however, displayed significant downregulation of genes related to embryonic developmental potential when compared to Con-IVM blastocysts.

CONCLUSIONS

Our results show that the use of the current version of the SPOM system may have adverse effects on oocytes and blastocysts calling for optimized protocols for improving oocyte competence.

Mammalian embryo comparison identifies novel pluripotency genes associated with the naïve or primed state

During early mammalian development, transient pools of pluripotent cells emerge that can be immortalised upon stem cell derivation. The pluripotent state, ‘naïve’ or ‘primed’, depends on the embryonic stage and derivation conditions used. Here we analyse the temporal gene expression patterns of mouse, cattle and porcine embryos at stages that harbour different types of pluripotent cells. We document conserved and divergent traits in gene expression, and identify predictor genes shared across the species that are associated with pluripotent states in vivo and in vitro. Amongst these are the pluripotency-linked genes Klf4 and Lin28b. The novel genes discovered include naïve- (Spic, Scpep1 and Gjb5) and primed-associated (Sema6a and Jakmip2) genes as well as naïve to primed transition genes (Dusp6 and Trip6). Both Gjb5 and Dusp6 play a role in pluripotency since their knockdown results in differentiation and downregulation of key pluripotency genes. Our interspecies comparison revealed new insights of pluripotency, pluripotent stem cell identity and a new molecular criterion for distinguishing between pluripotent states in various species, including human.

Summary: Interspecies comparison of mouse, bovine and pig embryos revealed conserved genes which distinguish between naïve and primed pluripotency states, including in human. Some of these genes interfere with the pluripotency network and lead to differentiation.

RNA-Guided Activation of Pluripotency Genes in Human Fibroblasts

Specific activation of endogenous genes can be achieved by programmable artificial transcription factors (ATFs). In this study, we compared two artificial, programmable, clustered regularly interspaced short palindromic repeats (CRISPR)-based, ubiquitous transcription factors: deficient CRISPR-associated protein 9 (dCas9)-VP64 (CRISPRa) alone, or a combination of dCas9-VP64 and MS2-P65-HSF1 [synergistic activation mediator (SAM) system] mediated activation of five pluripotency genes: KLF4 (K), LIN28 (L), MYC (M), OCT4 (O), and SOX2 (S) in human cells (HEK293T, HeLa, HepG2, and primary fibroblasts). Activation potential was monitored using a luciferase reporter system and we found that both CRISPRa and SAM can efficiently activate the proximal promoter of all five genes. We also observed that the guide RNA (gRNA) target sites and number of gRNAs have a major effect on gRNA-guided activation efficiency. Furthermore, increased activation efficiency (>3-folds) could be achieved by the SAM system compared to CRISPRa. In addition, we discovered that only the SAM system could efficiently activate LIN28, OCT4, and SOX2 expression (up to 100-folds compared to coexpression with a scrambled gRNA) in primary human fibroblasts. This SAM-mediated activation of LOS can be stably maintained for over 20 days in fibroblasts cultured in either fibroblasts or stem cell medium. However, when attempting to use the SAM-LOS activation as an approach for induced pluripotent stem cells-reprogramming, no embryonic stem-like colonies could be obtained from these SAM fibroblasts. In conclusion, our study showed that CRISPR/Cas9-based ATFs are potent to activate and maintain transcription of endogenous human pluripotent genes. However, future improvements of the system are still required to improve activation efficiency and cellular reprogramming using ATFs.

124 Cell Count of Bovine In Vitro-Produced Blastocysts After In Vitro Maturation in Glass versus Plastic Vials

Optimal bovine in vitro oocyte maturation (IVM) is a prerequisite for subsequent optimal blastocyst rates. Ovum pick-up (OPU), by which cumulus–oocyte complexes (COC) are collected in vivo, is performed outside a laboratory and often requires IVM to take place during transportation from the farm to the IVF laboratory. Hashem et al. (2017 Reprod. Fertil. Dev. 29, 179) demonstrated that blastocyst rates are affected by type of vial (glass v. plastic), number of COC per vial, and volume of medium per vial. This was achieved by maturing more than 2500 COC from slaughterhouse material under contrasting conditions, followed by standardised IVF and in vitro culture (IVC) and observation of blastocyst rates, morphology (1: poor; 2: good; 3: excellent), and kinetics (1: blastocyst; 2: expanded blastocyst ; 3: hatching/hatched blastocyst). Here we examined differential staining of a subset of expanded blastocysts (XB) from the previous study to assess the influence of vial material, medium volume, and number of COC per vial on total cell count, number and ratio of inner cell mass (ICM), and trophectoderm (TE) cells. In experiment 1 (4 groups), oocytes were matured in different vials without lids in an incubator at 5.5% CO2 in humidified atmospheric air at 38.5°C to assess plastic toxicity. In experiment 2 (6 groups) and experiment 3 (6 groups), the 2 best performing vials-polypropylene cryovials (Sigma-Aldrich, St. Louis, MO, USA) and glass vials (VWR International, Radnor, PA, USA)-containing 50% (Exp. 2) or 95% (Exp. 3) medium volume per vial and 5, 20, or 45 COC per vial were tested. In experiments 2 and 3, the vials were closed and incubated in atmospheric air at 38.5°C. All groups were evaluated for blastocyst rates, kinetics, and morphology. Because kinetics (range 2.01–2.25) and morphology (range 2.15–2.50) were similar in all groups, only XB were collected from each group. These were fixed and stained with CDX2 antibody and Hoechst (Wydooghe et al. 2011 Anal. Biochem. 416, 228-230) and their ICM and TE cells were counted. The cells were counted manually in blinded groups using an inverted fluorescence microscope and 16× magnification. Counts of total, ICM, and TE cells were compared between treatments by a two-way ANOVA analysis. A total of 240 XB from the 16 different vial groups were counted in the 3 experiments, with average total cell counts of 139 (110–211) and ICM cell counts of 44 (28–75). Even though the blastocyst rates differed between some of the groups, the cell counts within the XB did not differ statistically significantly between groups. In fact, the highest cell count was found in the glass vial group with the lowest blastocyst rate (45 COC per vial in 50% medium volume; blastocyst rate 28%, total cells 211, ICM cells 75). We have previously demonstrated that the type of vial, number of COC per vial, and the volume of medium per vial influence the subsequent blastocyst rates. It is concluded, however, that the embryos able to proceed to the blastocyst stages seem to be of the same quality in all groups, assessed by kinetics, morphology, and cell counts within XB.

Systematic in vitro and in vivo characterization of Leukemia-inhibiting factor- and Fibroblast growth factor-derived porcine induced pluripotent stem cells

Derivation and stable maintenance of porcine induced pluripotent stem cells (piPSCs) is challenging. We herein systematically analyzed two piPSC lines, derived by lentiviral transduction and cultured under either leukemia inhibitory factor (LIF) or fibroblast growth factor (FGF) conditions, to shed more light on the underlying biological mechanisms of porcine pluripotency. LIF‐derived piPSCs were more successful than their FGF‐derived counterparts in the generation of in vitro chimeras and in teratoma formation. When LIF piPSCs chimeras were transferred into surrogate sows and allowed to develop, only their prescence within the embryonic membranes could be detected. Whole‐transcriptome analysis of the piPSCs and porcine neonatal fibroblasts showed that they clustered together, but apart from the two pluripotent cell populations of early porcine embryos, indicating incomplete reprogramming. Indeed, bioinformatic analysis of the pluripotency‐related gene network of the LIF‐ versus FGF‐derived piPSCs revealed that ZFP42 (REX1) expression was absent in both piPSC‐like cells, whereas it was expressed in the porcine inner cell mass at Day 7/8. A second striking difference was the expression of ATOH1 in piPSC‐like cells, which was absent in the inner cell mass. Moreover, our gene expression analyses plus correlation analyses of known pluripotency genes identified unique relationships between pluripotency genes in the inner cell mass, which are to some extent, in the piPSC‐like cells. This deficiency in downstream gene activation and divergent gene expression may be underlie the inability to derive germ line‐transmitting piPSCs, and provides unique insight into which genes are necessary to achieve fully reprogrammed piPSCs. 84: 229–245, 2017. © 2016 Wiley Periodicals, Inc.

Neurons derived from sporadic Alzheimer's disease iPSCs reveal elevated TAU hyperphosphorylation, increased amyloid levels, and GSK3B activation

BACKGROUND

Alzheimer's disease (AD) is the most common type of dementia, affecting one in eight adults over 65 years of age. The majority of AD cases are sporadic, with unknown etiology, and only 5% of all patients with AD present the familial monogenic form of the disease. In the present study, our aim was to establish an in vitro cell model based on patient-specific human neurons to study the pathomechanism of sporadic AD.

METHODS

We compared neurons derived from induced pluripotent stem cell (iPSC) lines of patients with early-onset familial Alzheimer's disease (fAD), all caused by mutations in the PSEN1 gene; patients with late-onset sporadic Alzheimer's disease (sAD); and three control individuals without dementia. The iPSC lines were differentiated toward mature cortical neurons, and AD pathological hallmarks were analyzed by RT-qPCR, enzyme-linked immunosorbent assay, and Western blotting methods.

RESULTS

Neurons from patients with fAD and patients with sAD showed increased phosphorylation of TAU protein at all investigated phosphorylation sites. Relative to the control neurons, neurons derived from patients with fAD and patients with sAD exhibited higher levels of extracellular amyloid-β 1-40 (Aβ_1-40) and amyloid-β 1-42 (Aβ_1-42). However, significantly increased Aβ_1-42/Aβ_1-40 ratios, which is one of the pathological markers of fAD, were observed only in samples of patients with fAD. Additionally, we detected increased levels of active glycogen synthase kinase 3 β, a physiological kinase of TAU, in neurons derived from AD iPSCs, as well as significant upregulation of amyloid precursor protein (APP) synthesis and APP carboxy-terminal fragment cleavage. Moreover, elevated sensitivity to oxidative stress, as induced by amyloid oligomers or peroxide, was detected in both fAD- and sAD-derived neurons.

CONCLUSIONS

On the basis of the experiments we performed, we can conclude there is no evident difference except secreted Aβ_1-40 levels in phenotype between fAD and sAD samples. To our knowledge, this is the first study in which the hyperphosphorylation of TAU protein has been compared in fAD and sAD iPSC-derived neurons. Our findings demonstrate that iPSC technology is suitable to model both fAD and sAD and may provide a platform for developing new treatment strategies for these conditions.

Identification of SSEA-1 expressing enhanced reprogramming (SEER) cells in porcine embryonic fibroblasts

Previous research has shown that a subpopulation of cells within cultured human dermal fibroblasts, termed multilineage-differentiating stress enduring (Muse) cells, are preferentially reprogrammed into induced pluripotent stem cells. However, controversy exists over whether these cells are the only cells capable of being reprogrammed from a heterogeneous population of fibroblasts. Similarly, there is little research to suggest such cells may exist in embryonic tissues or other species. To address if such a cell population exists in pigs, we investigated porcine embryonic fibroblast populations (pEFs) and identified heterogeneous expression of several key cell surface markers. Strikingly, we discovered a small population of stage-specific embryonic antigen 1 positive cells (SSEA-1+) in Danish Landrace and Göttingen minipig pEFs, which were absent in the Yucatan pEFs. Furthermore, reprogramming of SSEA-1+ sorted pEFs led to higher reprogramming efficiency. Subsequent transcriptome profiling of the SSEA-1+ vs. the SSEA-1neg cell fraction revealed highly comparable gene signatures. However several genes that were found to be upregulated in the SSEA-1+ cells were similarly expressed in mesenchymal stem cells (MSCs). We therefore termed these cells SSEA-1 Expressing Enhanced Reprogramming (SEER) cells. Interestingly, SEER cells were more effective at differentiating into osteocytes and chondrocytes in vitro. We conclude that SEER cells are more amenable for reprogramming and that the expression of mesenchymal stem cell genes is advantageous in the reprogramming process. This data provides evidence supporting the elite theory and helps to delineate which cell types and specific genes are important for reprogramming in the pig.

Identification of potential biomarkers in donor cows for in vitro embryo production by granulosa cell transcriptomics

The Ovum Pick Up-In vitro Production (OPU-IVP) of embryos is an advanced reproductive technology used in cattle production but the complex biological mechanisms behind IVP outcomes are not fully understood. In this study we sequenced RNA of granulosa cells collected from Holstein cows at oocyte aspiration prior to IVP, to identify candidate genes and biological mechanisms for favourable IVP-related traits in donor cows where IVP was performed separately for each animal. We identified 56 genes significantly associated with IVP scores (BL rate, kinetic and morphology). Among these, BEX2, HEY2, RGN, TNFAIP6 and TXNDC11 were negatively associated while Mx1 and STC1 were positively associated with all IVP scores. Functional analysis highlighted a wide range of biological mechanisms including apoptosis, cell development and proliferation and four key upstream regulators (COX2, IL1, PRL, TRIM24) involved in these mechanisms. We found a range of evidence that good IVP outcome is positively correlated with early follicular atresia. Furthermore we showed that high genetic index bulls can be used in breeding without reducing the IVP performances. These findings can contribute to the development of biomarkers from follicular fluid content and to improving Genomic Selection (GS) methods that utilize functional information in cattle breeding, allowing a widespread large scale application of GS-IVP.

Ultrastructure and mitochondrial numbers in pre- and postpubertal pig oocytes

Prepubertal pig oocytes are associated with lower developmental competence. The aim of this experiment was to conduct an exhaustive survey of oocyte ultrastructure and to use a design-unbiased stereological approach to quantify the numerical density and total number of mitochondria in oocytes with different diameters from pre- and postpubertal pigs. The ultrastructure of smaller prepubertal immature oocytes indicated active cells in close contact with cumulus cells. The postpubertal oocytes were more quiescent cell types. The small prepubertal oocytes had a lower total mitochondrial number, but no differences were observed in mitochondrial densities between groups. Mature postpubertal oocytes adhered to the following characteristics: presence of metaphase II, lack of contact between cumulus cells and oocyte, absence of rough endoplasmic reticulum and Golgi complexes, peripheral location of cortical granules and central localisation of mitochondria, vesicles and lipid droplets. Prepubertal oocytes displayed more variation. The ultrastructure of large pre- and postpubertal oocytes was compatible with higher developmental competence, whereas that of smaller prepubertal oocytes could explain their reduced capacity. The higher number of mitochondria in large pre- and postpubertal oocytes could have an influence on oocyte competence, by increasing the pool of mitochondria available for early embryonic development.

Patient iPSC-Derived Neurons for Disease Modeling of Frontotemporal Dementia with Mutation in CHMP2B

The truncated mutant form of the charged multivesicular body protein 2B (CHMP2B) is causative for frontotemporal dementia linked to chromosome 3 (FTD3). CHMP2B is a constituent of the endosomal sorting complex required for transport (ESCRT) and, when mutated, disrupts endosome-to-lysosome trafficking and substrate degradation. To understand the underlying molecular pathology, FTD3 patient induced pluripotent stem cells (iPSCs) were differentiated into forebrain-type cortical neurons. FTD3 neurons exhibited abnormal endosomes, as previously shown in patients. Moreover, mitochondria of FTD3 neurons displayed defective cristae formation, accompanied by deficiencies in mitochondrial respiration and increased levels of reactive oxygen. In addition, we provide evidence for perturbed iron homeostasis, presenting an in vitro patient-specific model to study the effects of iron accumulation in neurodegenerative diseases. All phenotypes observed in FTD3 neurons were rescued in CRISPR/Cas9-edited isogenic controls. These findings illustrate the relevance of our patient-specific in vitro models and open up possibilities for drug target development.

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FTD3 neurons show abnormalities in endosomes and mitochondria

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Parkinson's and Alzheimer's disease core genes are altered in FTD3 neurons

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Iron homeostasis is perturbed in FTD3 neurons

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Impairments in FTD3 neurons are rescued in CRISPR/Cas9-edited isogenic controls

Androgen Insensitivity Syndrome in a Family of Warmblood Horses Caused by a 25-bp Deletion of the DNA-Binding Domain of the Androgen Receptor Gene

Testicular feminization, an earlier term coined for describing a syndrome resulting from failure of masculinization of target organs by androgen secretions during embryo development, has been well documented not only in humans but also in the domestic horse. The pathology, actually referred to as androgen insensitivity syndrome (AIS), has been proposed to follow an X-linked recessive pattern of inheritance in some horse breeds already investigated. Affected individuals are characterized by a female phenotype but with a stallion genotype of 64,XY SRY+ constitution. We identified a Warmblood horse pedigree segregating AIS, where the molecular analyses of the androgen receptor gene in the family provided evidences that a 25-bp deletion of the DNA-binding domain is causative of this equine syndrome.

141 BOVINE EMBRYO DEVELOPMENT RATES ARE AFFECTED WHEN OOCYTES ARE MATURED IN DIFFERENT VIALS CONTAINING HEPES/BICARBONATE BUFFERED MEDIUM

Laboratory ware for the in vitro-produced embryos is generally made from embryo-tested plastic instead of glass. The quality of the plastic is crucial for the outcome because plastic is often toxic to gametes (Nijs et al. 2009 Fertil. Steril. 92, 527–535). In addition, gas molecules permeate through the plastic at a rate that depends on a variety of factors, such as diffusion coefficient and thickness of the plastic. In an incubator with appropriate concentration of CO2 and vented culture vessels, the gas permeability of the plastic is not important. When oocytes are transported outside a controlled atmosphere, gas permeability, toxicity, and oocyte cumulus cell CO2 metabolism could perturb the outcome. Medium containing bicarbonate buffer increases pH outside of a controlled atmosphere within minutes, whereas medium buffered with HEPES maintains suitable pH for hours. Previously, we tested that gas permeability differs among plastic vials and glass vials with no cumulus-oocyte complexes (COC) by measuring pH after 2, 5, and 24 h at the same temperature. The objective of this study was to compare pH post-maturation, blastocyst development rates on Day 8 post-IVF (Day 0 = IVF) between 2 different 1.2-mL polypropylene cryovials (A: VWR DK, 479-1219; B: Sigma-Aldrich, St. Louis, MO, USA, CLS430289), glass vial (VWR DK, NSCAC4015-96), and 4-well plate (4WP) as control (Thermo Fisher Scientific, Waltham, MA, USA, 144444). A total of 1135 abattoir-derived COC in Exp. 1 and 133 in Exp. 2 were divided equally between the treatments (20–25 COC per vessel). Vials/4WP contained 0.8/0.5 mL of BO-IVM HEPES, a HEPES/bicarbonate medium (IVF Bioscience; BO-HEPES-IVM, UK). Maturation lasted 22 to 24 h at 38.8°C in an incubator with either a humidified atmosphere of 5.5% CO2 in air (Exp. 1) or with no CO2 contact (Exp. 2). In Exp. 1, oocyte vials were matured without a vial lid while in Exp. 2 vial lids were closed. Statistical analysis was performed with chi-square and mean ± SD. In Exp. 1, Day 8 blastocyst rates were evaluated as percentage of inseminated oocytes, with 4WP and glass vials significantly higher than cryovials A or B (38 ± 8.9%, 35 ± 7.5% v. 26 ± 3.2%, 26 ± 3.5%; respectively; P < 0.05). In Exp. 2, pH was measured for the 3 vials immediately post-maturation. Day 8 blastocyst rates were significantly higher in the glass vials as compared with cryovials A and B (pH 7.26, 31%; pH 7.60, 20% and pH 7.72, 22%, respectively; P < 0.05). In conclusion, blastocyst rates are affected by type of vial, as well as different gas permeability among other factors influencing pH. Further studies are necessary to optimize the maturation of the oocytes in HEPES-buffered media.

Generation of induced pluripotent stem cells (iPSCs) stably expressing CRISPR-based synergistic activation mediator (SAM)

Human fibroblasts were engineered to express the CRISPR-based synergistic activation mediator (SAM) complex: dCas9-VP64 and MS2-P65-HSF1. Two induced pluripotent stem cells (iPSCs) clones expressing SAM were established by transducing these fibroblasts with lentivirus expressing OCT4, SOX2, KLF4 and C-MYC. We have validated that the reprogramming cassette is silenced in the SAM iPSC clones. Expression of pluripotency genes (OCT4, SOX2, LIN28A, NANOG, GDF3, SSEA4, and TRA-1-60), differentiation potential to all three germ layers, and normal karyotypes are validated. These SAM-iPSCs provide a novel, useful tool to investigate genetic regulation of stem cell proliferation and differentiation through CRISPR-mediated activation of endogenous genes.

Induced pluripotent stem cells (iPSCs) derived from a symptomatic carrier of a S305I mutation in the microtubule-associated protein tau (MAPT)-gene causing frontotemporal dementia

Frontotemporal dementia with parkinsonism linked to chromosome 17q21.2 (FTDP-17) is an autosomal-dominant neurodegenerative disorder. Mutations in the gene coding the microtubule-associated protein tau (MAPT) can cause FTDP-17 but the underlying mechanisms of the disease are still unknown. Induced pluripotent stem cells (iPSCs) hold great promise to model FTDP-17 as such cells can be differentiated in vitro to the required neuronal cell type. Here, we report the generation of iPSCs from a 44-year-old symptomatic woman carrying a S305I mutation in the MAPT-gene.

Generation of an isogenic, gene-corrected iPSC line from a symptomatic 59-year-old female patient with frontotemporal dementia caused by an R406W mutation in the microtubule associated protein tau (MAPT) gene

Frontotemporal dementia with parkinsonism linked to chromosome 17q21.2 (FTDP-17) is an autosomal-dominant neurodegenerative disorder. Mutations in the MAPT (microtubule-associated protein tau) gene can cause FTDP-17, but the underlying pathomechanisms of the disease are still unknown. Induced pluripotent stem cells (iPSCs) hold great promise to model FTDP-17 as such cells can be differentiated in vitro to the required cell type. Furthermore, gene-editing approaches allow generating isogenic gene-corrected controls that can be used as a very specific control. Here, we report the generation of genetically corrected iPSCs from a 59-year-old female FTD-17 patient carrying an R406W mutation in the MAPT-gene.

Derivation of induced pluripotent stem cells from a familial Alzheimer's disease patient carrying the L282F mutation in presenilin 1

Mutations in presenilin 1 (PSEN1) lead to the most aggressive form of familial Alzheimer's disease (AD). Human induced pluripotent stem cells (hiPSCs) derived from AD patients can be differentiated and used for disease modeling. Here, we derived hiPSC from skin fibroblasts obtained from an AD patient carrying a L282F mutation in PSEN1. We transfected skin fibroblasts with episomal iPSC reprogramming vectors targeting human OCT4, SOX2, L-MYC, KLF4, NANOG, LIN28, and short hairpin RNA against TP53. Our hiPSC line, L282F-hiPSC, displayed typical stem cell characteristics with consistent expression of pluripotency genes and the ability to differentiation into the three germ layers.