Effect of tissue source on adult equine multipotent stromal cell pluripotency induction treatment with synthetic mRNA

Autogenous and autologous adult multipotent stromal cells are applied to treat equine musculoskeletal injuries in clinical practice. However, options for autologous therapy in the equine specie are restricted due to the limited biological material obtained or MSCs tissue harvest procedure and because of their unpredictable in vivo behavior. Induced pluripotent stem cells represent an alternative to overcome these limitations. Traditionally, iPSCs are produced by introducing DNA for early embryonic genes into cells with viruses. The method tested in this study, avoids the use of viral vectors and potential for exogenous DNA integration into the cell’s genome by utilizing a lipid delivery vehicle carrying synthetic mRNA coding for the human pluripotency factors OCT4, KLF4 and SOX2. Cells from different tissue have specific epigenetic profiles that determine their phenotype and functionality; hence they might have a distinct susceptibility to induction of pluripotency. This study was designed to test the expansion capacity and potency of equine adult MSCs from adipose tissue, bone marrow, and fibroblast following chemical transfection with synthetic mRNA of human sequences for embryonic genes, OCT4, KLF4 and SOX2. Target gene mRNA and cell protein expression was compared among passage (P) 3 cells from the different tissue sources before and after 7 and 14 days of transduction. Additionally, multilineage capacity and expansion rate were compared in P10 cells. Target protein expression localized to the nucleus was higher in transduced cells at both time points compared to untreated cells based on immunocytochemistry. Based on qRT-PCR, OCT4 and SOX2 expression was significantly higher in transfected cells after 14 days of transduction compared untreated cells (Oct4: ASCs, P=0.030; BMSCs, P=0.005 and fibroblast, P\u3c0.001; Sox-2: ASCs, P=0.012; BMSCs, P=0.001 and fibroblast, P=0.005). Multilineage differentiation was detected in transfected versus untreated cells both at passage 10 by histological staining after differentiation. Expansion rates of transduced and untreated cells were not different with the exception of BMSCs (P\u3c0.05). Based on these results, dedifferentiation of equine MSCs with synthetic mRNA increases in vitro potency and expansion capacity. The ability to induce pluripotency from MSCs obtained from multiple equine tissue sources will significantly increase accessibility to highly characterized stem cells. This will in turn improve the ability to predict cell behavior for customized therapies, becoming an important model for future human applications

THE PARKINSON’S DISEASE ASSOCIATED PINK1-PARKIN PATHWAY IN PATHOLOGY AND DEVELOPMENT

Parkinson’s disease (PD) has an aetiology not completely understood. One of the hypothesis in the field is that many neurodegenerative diseases are influenced by developmental disorders. The underlying concept is that already during brain development some processes are deregulated producing a higher degree of susceptibility for neurodegeneration during aging. Two hereditary early onset forms of PD are caused by recessive mutations in PTEN-induced putative kinase 1 (PINK1) and Parkin genes that regulate mitochondrial function and morphology, quarantining damaged mitochondria before their degradation as well as triggering the process of mitophagy. Our hypothesis is that alterations of the Pink1-Parkin pathway have an impact in mitochondrial physiology tempering the differentiation ability of neuroepithelial stem cells into dopaminergic neurons. For evaluating this hypothesis we reprogramed patients’ fibroblasts carrying PINK1 mutations, as well as from healthy individuals, to human induced pluripotent stem cells. We developed a streamlined technique of gene editing (FACE) by using the CRISPR/Cas9 system combined with a composite of fluorescent proteins in the donor template for biallelic gene targeting. Isogenic controls were generated using this technique that allowed us to analyze the contribution of corrected patients’ mutations in the cellular defects observed. Human iPSCs were differentiated into a neuroepithelial stem cell state (NESC) from where the cells were further differentiated into neurons. We established different algorithms for pattern recognition and applied them for image analysis of different features such as mitochondrial morphology, proliferation capacity, apoptosis and differentiation. Patient’s derived cells presented an impaired differentiation efficiency into dopaminergic neurons as well as an imbalanced cell renewal that can be linked to the mitochondrial differences. Using 3D cultures, such as microfluidics and organoids, we were able to recapitulate this differentiation impairment in a system that mimics better the context of an in vivo environment. We evaluated the energetic capabilities of the NESCs and the firing activity of differentiated neurons, which also showed a dysregulation in patient cells. We introduced a new system for large-scale analysis of the autophagy and mitophagy pathways by the combination of stably integrated Rosella constructs in different patients’ lines and an image analysis script for classification of the different subcellular structures involved in these pathways activities. This revealed that the basal activity as well as the response against stressors of these pathways are altered in cells derived from patients having different mutations causative of PD. We performed a screen of repurposed drugs as well as of novel compounds to evaluate their impact in this altered developmental transition identifying a potential candidate to be further analysed in an in vivo context

Effect of collection-maturation interval time and pregnancy status of donor mares on oocyte developmental competence in horse cloning

The current limitations for obtaining ovaries from slaughterhouses and the low efficiency of in vivo follicular aspiration necessitate a complete understanding of the variables that affect oocyte developmental competence in the equine. For this reason, we assessed the effect on equine oocyte meiotic competence and the subsequent in vitro cloned embryo development of 1) the time interval between ovary collection and the onset of oocyte in vitro maturation (collection-maturation interval time) and 2) the pregnancy status of the donor mares. To define the collection-maturation interval time, collected oocytes were classified according to the slaughtering time and the pregnancy status of the mare. Maturation rate was recorded and some matured oocytes of each group were used to reconstruct zona free cloned embryos. Nuclear maturation rates were lower when the collection-maturation interval time exceeded 10 h as compared to 4 h (32/83 vs. 76/136, respectively; P = 0.0128) and when the donor mare was pregnant as compared to nonpregnant (53/146 vs. 177/329, respectively; P = 0.0004). Low rates of cleaved embryos were observed when the collection-maturation interval time exceeded 10 h as compared to 6 to 10 h (11/27 vs. 33/44, respectively; P = 0.0056), but the pregnancy status of donor mares did not affect cloned equine blastocyst development (3/49 vs. 1/27 for blastocyst rates of nonpregnant and pregnant groups, respectively; P = 1.00). These results indicate that, to apply assisted reproductive technologies in horses, oocytes should be harvested within approximately 10 h after ovary collection. Also, even though ovaries from pregnant mares are a potential source of oocytes, they should be processed at the end of the collection routine due to the lower collection and maturation rate in this group.Fil: Gambini, Andres. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Jarazo, Javier. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; ArgentinaFil: Karlanian, Florencia. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; ArgentinaFil: de Stéfano, Adrian. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; ArgentinaFil: Salamone, Daniel Felipe. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentin

Guidelines for Fluorescent Guided Biallelic HDR Targeting Selection With PiggyBac System Removal for Gene Editing

The development of new and easy-to-use nucleases, such as CRISPR/Cas9, made tools for gene editing widely accessible to the scientific community. Cas9-based gene editing protocols are robust for creating knock-out models, but the generation of single nucleotide transitions or transversions remains challenging. This is mainly due to the low frequency of homology directed repair, which leads to the screening of a high number of clones to identify positive events. Moreover, lack of simultaneous biallelic modifications, frequently results in second-allele indels. For example, while one allele might undergo homology directed repair, the second can undergo non-homologous end joining repair. Here we present a step-wise protocol for biallelic gene editing. It uses two donors carrying a combination of fluorescent reporters alongside homology arms directed to the same genomic region for biallelic targeting. These homology arms carry the desired composite of modifications to be introduced (homozygous or heterozygous changes). Plus, the backbone of the plasmid carries a third fluorescent reporter for negative selection (to discard random integration events). Fluorescent selection of non-random biallelic targeted clones can be performed by microscopy guided picking or cell sorting (FACS). The positive selection module (PSM), carrying the fluorescence reporter and an antibiotic resistance, is flanked by inverted terminal repeats (ITR) that are recognized by transposase. Upon purification of the clones correctly modified, transfection of the excision-only transposase allows the removal of the PSM resulting in the integration of only the desired modifications

SARS-COV-2 INDUCES DOPAMINERGIC NEURON LOSS IN MIDBRAIN ORGANOIDS

peer reviewedObjectives: COVID-19 presents numerous symptoms mostly associated with the respiratory tract. However, recent evidence showed that the SARS-CoV-2 virus affects the nervous system. We evaluated the effect of the infection in midbrain organoids to determine if cells and pathways related to the onset of Parkinson’s disease (PD) are affected. Methods: The effect of the virus after short- and long-term cultures (4 days, and 1 month) postinfection was analyzed. Features measured included the degree of dopaminergic differentiation (TH), neurite fragmentation, and the level of activated astrocytes (GFAP and S100beta). Bulk RNAseq was performed to determine the effects of the infection on gene expression. Results: After infection with SARS-CoV-2, the levels of dopaminergic neurons were significantly reduced in both short and long-term culture. Moreover, neurite fragmentation of TH positive neurons in infected organoids significantly increased respective to controls in long-term cultures. Within the same infected organoid TH/SARS-CoV-2 double positive neurons presented an altered morphology and high degree of neurite fragmentation compared to uninfected TH positive neurons. Activation of astrocytes was significantly reduced after infection in the short-term culture. While the levels of S100beta recovered over time, they still remained lower in infected organoids. In both short- and long-term culture, SARS-CoV-2 colocalized more with certain types of cells showing a marked preference for GFAP positive and TH positive cells when normalized to their respective abundance in the organoid. Gene expression analysis revealed a disruption in gene pathways related to vesicle transport, endosomal and autophagy pathways following infection with SARS-CoV-2. Conclusions: Infection of midbrain organoids with SARS-CoV-2 induced a clear neurodegenerative process of TH positive neurons, while disrupting main pathways known to be involved in Parkinson's disease.R-AGR-0592 - FNR - NCER-PD Phase II Coordination (01/06/2015 - 30/11/2023) - KRÜGER Rejko3. Good health and well-bein

Recent advances in micromanipulation and transgenesis in domestic mammals

Background: Intracytoplasmic sperm injection (ICSI) involves mechanical transfer of a single sperm cell into ooplasm. A new application has been recently found for ICSI, the production of transgenic animals. Since the birth of ‘‘Dolly’’, the first adult somatic cloned mammal, viable offspring has been produced by nuclear transfer in many species including cattle. The present review briefly summarizes our experience with ICSI and somatic cell nuclear transfer mainly to produce transgenic embryos, as well as for the generation of new micromanipulation technique. Review: We have evaluated different factors that affect SCNT and transgenesis including the chemical activator, the transfection event and the effect of recloning. Also, we included a brief description of the ICSI technique, which we used in five different species, examining its potential to produce transgenic embryos. Finally different strategies to produce transgenic animals were analyzed: ICSI- mediated gen transfer (ICSI-MGT), Injection of cumulus cell and ooplasmic vesicle incubated for 5 min with the transgene or injection of the plasmid alone. All of them were very efficient in exogenous DNA expression at embryo stages but resulted in mosaic embryos. We demonstrated that “ICSI-MGT” assisted by chemical activation is the only treatment of sperm mediated gen transfer capable to generated transgenic embryos in ovine. Besides, after ICSI-MGT, it is possible to obtain enhanced green fluorescent protein (EGFP)-expressing embryos in five diferent species: ovine, porcine, feline, bovine and equine. Our studies also established for the first time that short term transgene co-incubation with somatic cells can produce transgene-expressing mammalian SCNT embryos, and also that parthenogenic, eDNA- expressing embryos can be obtained by injection of vesicles or eDNA alone. Moreover, eDNA-expressing embryos can be also obtained by cytoplasmic injection of vesicles in IVF zygotes, simplifying the traditional IVF pronuclear injection technique. We tried a further simplification of the technique in bovine oocytes and zygotes, by intracytoplasmically injecting them with eDNA-liposomes complexes. Approximately 70% of the cleaved embryos and 50% of the blastocysts expressed EGFP, when egfp–liposome was injected 16 h post-fertilization. Different approaches were assayed to reverse the mosaicism including a novel technique of gamete cloning. Our first approach consisted of the production of transgenic IVF embryos by vesicle microinjection to generate transgenic blastomeres to be used as donor cells for cloning. A high efficiency in mosaicism reversal and multiplication of transgenic embryos was attaineded. Other technique assayed was the separation of transgenic blastomeres followed by the aggregation of two-cell fused embryos or by the asynchronous younger blastomere successfully multiplied transgenic embryos, and theoretically reduces mosaicism rates in future offspring [15]. This technology can also be used to multiply embryos from animals with high genetic value. We demonstrated that a sperm and oocyte can be efficiently cloned. Green haploid androgenic blastomeres produced with the injection of a single sperm by egfp ICSI-MGT could be used to fertilized oocytes resulting in several homogeneous expressing embryos. This approach shows great potential because it allows for determination of the sex of the sperm nucleus prior to fertilization. It is also possible to clone previously transfected oocytes followed by the reconstruction of biparental bovine embryos to generate homogeneous transgene-expressing embryos. This review summarizes recent experiments in micromanipulation and gene transfer in domestic animals. The objective is not to exhaustedly describe the research done in this field but to present the promising methods recently developed or evaluated in our lab. Conclusion: Significant advancements have been made in the course of the recent years in micromanipulation and transgenesis techniques. In our lab we have been evaluating ICSI and Nuclear transfer mainly to produce transgenic embryos. We used also transgensis to apply or developed new micromanipulation technique in domestic animals linke sperm and oocyte cloning.Fil: Salamone, Daniel Felipe. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Pque. Centenario. Unidad Ejecutora de Investigaciones En Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones En Producción Animal; ArgentinaFil: Bevacqua, Romina Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Pque. Centenario. Unidad Ejecutora de Investigaciones En Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones En Producción Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Pereyra Bonnet, Federico Alberto. Hospital Italiano; ArgentinaFil: Gambini, Andres. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal. Cátedra de Fisiología Animal; ArgentinaFil: Canel, Natalia Gabriela. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal. Cátedra de Fisiología Animal; ArgentinaFil: Hiriart, María Inés. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal. Cátedra de Fisiología Animal; ArgentinaFil: Vichera, Gabriel Damian. Universidad Nacional de San Martín; ArgentinaFil: Moro, Lucía Natalia. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Jarazo, Javier

Mitochondrial and Clearance Impairment in p.D620N VPS35 Patient-Derived Neurons

Background: VPS35 is part of the retromer complex and is responsible for the trafficking and recycling of proteins implicated in autophagy and lysosomal degradation, but also takes part in the degradation of mitochondrial proteins via mitochondria-derived vesicles. The p.D620N mutation of VPS35 causes an autosomal-dominant form of Parkinson’s disease (PD), clinically representing typical PD. Objective: Most of the studies on p.D620N VPS35 were performed on human tumor cell lines, rodent models overexpressing mutant VPS35, or in patient-derived fibroblasts. Here, based on identified target proteins, we investigated the implication of mutant VPS35 in autophagy, lysosomal degradation, and mitochondrial function in induced pluripotent stem cell-derived neurons from a patient harboring the p.D620N mutation. Methods: We reprogrammed fibroblasts from a PD patient carrying the p.D620N mutation in the VPS35 gene and from two healthy donors in induced pluripotent stem cells. These were subsequently differentiated into neuronal precursor cells to finally generate midbrain dopaminergic neurons. Results: We observed a decreased autophagic flux and lysosomal mass associated with an accumulation of α-synuclein in patient-derived neurons compared to controls. Moreover, patient-derived neurons presented a mitochondrial dysfunction with decreased membrane potential, impaired mitochondrial respiration, and increased production of reactive oxygen species associated with a defect in mitochondrial quality control via mitophagy. Conclusion: We describe for the first time the impact of the p.D620N VPS35 mutation on autophago-lysosome pathway and mitochondrial function in stem cell-derived neurons from an affected p.D620N carrier and define neuronal phenotypes for future pharmacological intervention

Recientes avances en micromanipulación y transgénesis en mamíferos domésticos

Esta revisión describe los trabajos que hemos realizado en el Laboratorio de Biotecnología Animal de la Facultad de Agronomía de la Universidad de Buenos Aires y trabajos hechos en colaboración con una empresa de biotecnología argentina. Los experimentos realizados fueron principalmente en el área de micromanipulación embrionaria y transgénesis animal. Se describen experiencias de transgénesis por transplante nuclear utilizando células genéticamente modificadas incluyendo la reclonacion de animales transgénicos. Luego se presentan resultados en que mediante la inyección intracitoplasmática de espermatozoide (ICSI) permitieron producir embriones trasgénicos en cinco especies domésticas diferentes. Otros trabajos descriptos exploran numerosas alternativas para generar transgénesis por ICSI en bovinos y ovinos. Seguidamente se analizaron varias estrategias para producir animales transgénicos entre ellas la inyección en oocitos o cigotos de células del cúmulos, vesícula ooplásmica ambas previamente incubadas durante 5 minutos con la transgen o la inyección del plásmido solo. Todos estos tratamientos fueron eficientes induciendo la expresión de ADN exógeno en embriones preimplantados. Sin embargo hubo un gran mosaiquismo en la expresión del transgen. Varias estrategias fueron analizadas para revertir el mosaiquismo incluyendo una novedosa técnica de clonación de gametos. Concluimos que múltiples métodos nuevos de micromanipulación y transgénesis están disponibles ahora para ser empleados en las especies domésticas.Academia Nacional de Agronomía y Veterinaria (ANAV

Automated micro uidic cell culture of stem cell derived dopaminergic neurons in Parkinson's disease

AbstractParkinson’s disease is a slowly progressive neurodegenerative disease characterised by dysfunction and death of selectively vulnerable midbrain dopaminergic neurons leading mainly to motor dysfunction, but also other non-motor symptoms. The development of human in vitro cellular models with similar phenotypic characteristics to selectively vulnerable neurons is a major challenge in Parkinson’s disease research. We constructed a fully automated cell culture platform optimised for long-term maintenance and monitoring of induced pluripotent stem cell derived neurons in three dimensional microfluidic cell culture devices. The system can be flexibly adapted to various experimental protocols and features time-lapse imaging microscopy for quality control and electrophysiology monitoring to assess neuronal activity. Using this system, we continuously monitored the differentiation of Parkinson’s disease patient derived human neuroepithelial stem cells into midbrain specific dopaminergic neurons. Calcium imaging confirmed the electrophysiological activity of differentiated neurons and immunostaining confirmed the efficiency of the differentiation protocol. This system is the first example of a fully automated Organ-on-a-Chip culture and enables a versatile array of in vitro experiments for patient-specific disease modelling.</jats:p

Microglia integration into human midbrain organoids leads to increased neuronal maturation and functionality

The human brain is a complex, three-dimensional structure. To better recapitulate brain complexity, recent efforts have focused on the development of human-specific midbrain organoids. Human iPSC-derived midbrain organoids consist of differentiated and functional neurons, which contain active synapses, as well as astrocytes and oligodendrocytes. However, the absence of microglia, with their ability to remodel neuronal networks and phagocytose apoptotic cells and debris, represents a major disadvantage for the current midbrain organoid systems. Additionally, neuroinflammation-related disease modeling is not possible in the absence of microglia. So far, no studies about the effects of human iPSC-derived microglia on midbrain organoid neural cells have been published. Here we describe an approach to derive microglia from human iPSCs and integrate them into iPSC-derived midbrain organoids. Using single nuclear RNA Sequencing, we provide a detailed characterization of microglia in midbrain organoids as well as the influence of their presence on the other cells of the organoids. Furthermore, we describe the effects that microglia have on cell death and oxidative stress-related gene expression. Finally, we show that microglia in midbrain organoids affect synaptic remodeling and increase neuronal excitability. Altogether, we show a more suitable system to further investigate brain development, as well as neurodegenerative diseases and neuroinflammation