Different gene expression profiles in iPSC-derived motor neurons from ALS8 patients with variable clinical courses suggest mitigating pathways for neurodegeneration.

Amyotrophic lateral sclerosis type 8 (ALS8) is an autosomal dominant form of ALS, which is caused by pathogenic variants in the VAPB gene. Here we investigated five ALS8 patients, classified as 'severe' and 'mild' from a gigantic Brazilian kindred, carrying the same VAPB mutation but displaying different clinical courses. Copy number variation and whole exome sequencing analyses in such individuals ruled out previously described genetic modifiers of pathogenicity. After deriving induced pluripotent stem cells (iPSCs) for each patient (N = 5) and controls (N = 3), motor neurons were differentiated, and high-throughput RNA-Seq gene expression measurements were performed. Functional cell death and oxidative metabolism assays were also carried out in patients' iPSC-derived motor neurons. The degree of cell death and mitochondrial oxidative metabolism were similar in iPSC-derived motor neurons from mild patients and controls and were distinct from those of severe patients. Similar findings were obtained when RNA-Seq from such cells was performed. Overall, 43 genes were upregulated and 66 downregulated in the two mild ALS8 patients when compared with severe ALS8 individuals and controls. Interestingly, significantly enriched pathways found among differentially expressed genes, such as protein translation and protein targeting to the endoplasmic reticulum (ER), are known to be associated with neurodegenerative processes. Taken together, the mitigating mechanisms here presented appear to maintain motor neuron survival by keeping translational activity and protein targeting to the ER in such cells. As ALS8 physiopathology has been associated with proteostasis mechanisms in ER-mitochondria contact sites, such differentially expressed genes appear to relate to the bypass of VAPB deficiency.

Inositol monophosphatase 1 (IMPA1) mutation in intellectual disability patients impairs neurogenesis but not gliogenesis.

A homozygous mutation in the inositol monophosphatase 1 (IMPA1) gene was recently identified in nine individuals with severe intellectual disability (ID) and disruptive behavior. These individuals belong to the same family from Northeastern Brazil, which has 28 consanguineous marriages and 59 genotyped family members. IMPA1 is responsible for the generation of free inositol from de novo biosynthesis and recycling from inositol polyphosphates and participates in the phosphatidylinositol signaling pathway. To understand the role of IMPA1 deficiency in ID, we generated induced pluripotent stem cells (iPSCs) from patients and neurotypical controls and differentiated these into hippocampal dentate gyrus-like neurons and astrocytes. IMPA1-deficient neuronal progenitor cells (NPCs) revealed substantial deficits in proliferation and neurogenic potential. At low passage NPCs (P1 to P3), we observed cell cycle arrest, apoptosis, progressive change to a glial morphology and reduction in neuronal differentiation. These observations were validated by rescuing the phenotype with myo-inositol supplemented media during differentiation of patient-derived iPSCs into neurons and by the reduction of neurogenic potential in control NPCs-expressing shIMPA1. Transcriptome analysis showed that NPCs and neurons derived from ID patients have extensive deregulation of gene expression affecting pathways necessary for neurogenesis and upregulation of gliogenic genes. IMPA1 deficiency did not affect cell cycle progression or survival in iPSCs and glial progenitor cells or astrocyte differentiation. Therefore, this study shows that the IMPA1 mutation specifically affects NPC survival and neuronal differentiation.

Safety, Tumor Reduction, and Clinical Impact of Zika Virus Injection in Dogs with Advanced-Stage Brain Tumors.

Malignant brain tumors are among the most aggressive cancers with poor prognosis and no effective treatment. Recently, we reported the oncolytic potential of Zika virus infecting and destroying the human central nervous system (CNS) tumors in vitro and in immunodeficient mice model. However, translating this approach to humans requires pre-clinical trials in another immunocompetent animal model. Here, we analyzed the safety of Brazilian Zika virus (ZIKVBR) intrathecal injections in three dogs bearing spontaneous CNS tumors aiming an anti-tumoral therapy. We further assessed some aspects of the innate immune and inflammatory response that triggers the anti-tumoral response observed during the ZIKVBR administration in vivo and in vitro. For the first time, we showed that there were no negative clinical side effects following ZIKVBR CNS injections in dogs, confirming the safety of the procedure. Furthermore, the intrathecal ZIKVBR injections reduced tumor size in immunocompetent dogs bearing spontaneous intracranial tumors, improved their neurological clinical symptoms significantly, and extended their survival by inducing the destruction specifically of tumor cells, sparing normal neurons, and activating an immune response. These results open new perspectives for upcoming virotherapy using ZIKV to destroy and induce an anti-tumoral immune response in CNS tumors for which there are currently no effective treatments.

Hepatoblastomas exhibit marked NNMT downregulation driven by promoter DNA hypermethylation.

Hepatoblastomas exhibit the lowest mutational burden among pediatric tumors. We previously showed that epigenetic disruption is crucial for hepatoblastoma carcinogenesis. Our data revealed hypermethylation of nicotinamide N-methyltransferase, a highly expressed gene in adipocytes and hepatocytes. The expression pattern and the role of nicotinamide N-methyltransferase in pediatric liver tumors have not yet been explored, and this study aimed to evaluate the effect of nicotinamide N-methyltransferase hypermethylation in hepatoblastomas. We evaluated 45 hepatoblastomas and 26 non-tumoral liver samples. We examined in hepatoblastomas if the observed nicotinamide N-methyltransferase promoter hypermethylation could lead to dysregulation of expression by measuring mRNA and protein levels by real-time quantitative polymerase chain reaction, immunohistochemistry, and Western blot assays. The potential impact of nicotinamide N-methyltransferase changes was evaluated on the metabolic profile by high-resolution magic angle spinning nuclear magnetic resonance spectroscopy. Significant nicotinamide N-methyltransferase downregulation was revealed in hepatoblastomas, with two orders of magnitude lower nicotinamide N-methyltransferase expression in tumor samples and hepatoblastoma cell lines than in hepatocellular carcinoma cell lines. A specific TSS1500 CpG site (cg02094283) of nicotinamide N-methyltransferase was hypermethylated in tumors, with an inverse correlation between its methylation level and nicotinamide N-methyltransferase expression. A marked global reduction of the nicotinamide N-methyltransferase protein was validated in tumors, with strong correlation between gene and protein expression. Of note, higher nicotinamide N-methyltransferase expression was statistically associated with late hepatoblastoma diagnosis, a known clinical variable of worse prognosis. In addition, untargeted metabolomics analysis detected aberrant lipid metabolism in hepatoblastomas. Data presented here showed the first evidence that nicotinamide N-methyltransferase reduction occurs in hepatoblastomas, providing further support that the nicotinamide N-methyltransferase downregulation is a wide phenomenon in liver cancer. Furthermore, this study unraveled the role of DNA methylation in the regulation of nicotinamide N-methyltransferase expression in hepatoblastomas, in addition to evaluate the potential effect of nicotinamide N-methyltransferase reduction in the metabolism of these tumors. These preliminary findings also suggested that nicotinamide N-methyltransferase level may be a potential prognostic biomarker for hepatoblastoma.

10q23.31 microduplication encompassing PTEN decreases mTOR signalling activity and is associated with autosomal dominant primary microcephaly.

BACKGROUND: Hereditary primary microcephaly (MCPH) is mainly characterised by decreased occipitofrontal circumference and variable degree of intellectual disability. MCPH with a dominant pattern of inheritance is a rare condition, so far causally linked to pathogenic variants in the ALFY, DPP6, KIF11 and DYRK1A genes. OBJECTIVE: This study aimed at identifying the causative variant of the autosomal dominant form of MCPH in a Brazilian family with three affected members. METHODS: Following clinical evaluation of two sibs and their mother presenting with autosomal dominant MCPH, array comparative genome hybridisation was performed using genomic DNA from peripheral blood of the family members. Gene and protein expression studies were carried out in cultured skin fibroblasts. RESULTS: A 382 kb microduplication at 10q23.31 was detected, encompassing the entire PTEN, KLLN and ATAD1 genes. PTEN haploinsufficiency has been causally associated with macrocephaly and autism spectrum disorder and, therefore, was considered the most likely candidate gene to be involved in this autosomal dominant form of MCPH. In the patients' fibroblasts, PTEN mRNA and protein were found to be overexpressed, and the phosphorylation patterns of upstream and downstream components of the mammalian target of rapamycin (mTOR) signalling pathway were dysregulated. CONCLUSIONS: Taken together, our results demonstrate that the identified submicroscopic 10q23.31 duplication in a family with MCPH leads to markedly increased expression of PTEN and reduced activity of the mTOR signalling pathway. These results suggest that the most probable pathomechanism underlying the microcephaly phenotype in this family involves downregulation of the mTOR pathway through overexpression of PTEN.

EIF4A3 deficient human iPSCs and mouse models demonstrate neural crest defects that underlie Richieri-Costa-Pereira syndrome.

Biallelic loss-of-function mutations in the RNA-binding protein EIF4A3 cause Richieri-Costa-Pereira syndrome (RCPS), an autosomal recessive condition mainly characterized by craniofacial and limb malformations. However, the pathogenic cellular mechanisms responsible for this syndrome are entirely unknown. Here, we used two complementary approaches, patient-derived induced pluripotent stem cells (iPSCs) and conditional Eif4a3 mouse models, to demonstrate that defective neural crest cell (NCC) development explains RCPS craniofacial abnormalities. RCPS iNCCs have decreased migratory capacity, a distinct phenotype relative to other craniofacial disorders. Eif4a3 haploinsufficient embryos presented altered mandibular process fusion and micrognathia, thus recapitulating the most penetrant phenotypes of the syndrome. These defects were evident in either ubiquitous or NCC-specific Eif4a3 haploinsufficient animals, demonstrating an autonomous requirement of Eif4a3 in NCCs. Notably, RCPS NCC-derived mesenchymal stem-like cells (nMSCs) showed premature bone differentiation, a phenotype paralleled by premature clavicle ossification in Eif4a3 haploinsufficient embryos. Likewise, nMSCs presented compromised in vitro chondrogenesis, and Meckel's cartilage was underdeveloped in vivo. These findings indicate novel and essential requirements of EIF4A3 for NCC migration and osteochondrogenic differentiation during craniofacial development. Altogether, complementary use of iPSCs and mouse models pinpoint unique cellular mechanisms by which EIF4A3 mutation causes RCPS, and provide a paradigm to study craniofacial disorders.

Revascularization of decellularized lung scaffolds: principles and progress.

There is a clear unmet clinical need for novel biotechnology-based therapeutic approaches to lung repair and/or replacement, such as tissue engineering of whole bioengineered lungs. Recent studies have demonstrated the feasibility of decellularizing the whole organ by removal of all its cellular components, thus leaving behind the extracellular matrix as a complex three-dimensional (3D) biomimetic scaffold. Implantation of decellularized lung scaffolds (DLS), which were recellularized with patient-specific lung (progenitor) cells, is deemed the ultimate alternative to lung transplantation. Preclinical studies demonstrated that, upon implantation in rodent models, bioengineered lungs that were recellularized with airway and vascular cells were capable of gas exchange for up to 14 days. However, the long-term applicability of this concept is thwarted in part by the failure of current approaches to reconstruct a physiologically functional, quiescent endothelium lining the entire vascular tree of reseeded lung scaffolds, as inferred from the occurrence of hemorrhage into the airway compartment and thrombosis in the vasculature in vivo. In this review, we explore the idea that successful whole lung bioengineering will critically depend on 1) preserving and/or reestablishing the integrity of the subendothelial basement membrane, especially of the ultrathin respiratory membrane separating airways and capillaries, during and following decellularization and 2) restoring vascular physiological functionality including the barrier function and quiescence of the endothelial lining following reseeding of the vascular compartment. We posit that physiological reconstitution of the pulmonary vascular tree in its entirety will significantly promote the clinical translation of the next generation of bioengineered whole lungs.

iPSC-derived cells for whole liver bioengineering.

Liver bioengineering stands as a prominent alternative to conventional hepatic transplantation. Through liver decellularization and/or bioprinting, researchers can generate acellular scaffolds to overcome immune rejection, genetic manipulation, and ethical concerns that often accompany traditional transplantation methods, in vivo regeneration, and xenotransplantation. Hepatic cell lines derived from induced pluripotent stem cells (iPSCs) can repopulate decellularized and bioprinted scaffolds, producing an increasingly functional organ potentially suitable for autologous use. In this mini-review, we overview recent advancements in vitro hepatocyte differentiation protocols, shedding light on their pivotal role in liver recellularization and bioprinting, thereby offering a novel source for hepatic transplantation. Finally, we identify future directions for liver bioengineering research that may allow the implementation of these systems for diverse applications, including drug screening and liver disease modeling.

Stem Cell Technology in Organ Transplantation: A Novel Method for 3D Bioprinting Functional and Stable Liver Grafts Using Human iPS Cells Derived Cells.

For decades, scientists and physicians aim to generate functional human tissues in the laboratory using stem cells. In this section, we will describe a novel method that combines state-of-the-art stem cell culture with 3D bioprinting to generate potentially transplantable tissue grafts. For this purpose, we will use the liver as a model. The liver is an important metabolic hub and responsible to perform many endocrine and exocrine vital functions. It is estimated that two million deaths/year are associated with liver disease. This illustrates the need for developing new efficient alternatives for liver transplantation. Modern 3D bioprinting technologies in combination with autologous induced pluripotent stem cells (iPS)-derived grafts could represent a relevant tissue engineering approach to treat end-stage liver disease. Here, we described a novel method for 3D bioprinting functional and stable liver grafts using human iPS-derived cells. The novel method described in this section uses the hepatocyte-like cells in a spheroid culture format (i.e., obtained from three-dimensional cell culture), in combination or not with non-parenchymal cells (e.g., mesenchymal and endothelial cells), which generates the final liver graft. This method has proved to sustain epithelial phenotype and to increase the stability and functionality of the constructs for prolonged periods.

A Review of Stem Cell Technology Targeting Hepatocyte Growth as an Alternative to Organ Transplantation.

Currently, the only feasible option for patients with progressive and/or end-stage organ degeneration is to undergo transplantation. Due to the growing unmatched demand of available organ donors and, as a consequence, the continuous growth of patients' waiting lists, the development of new tissue engineering technologies is a relevant need. In this chapter, we will focus on the liver as a model organ to discuss contemporary tissue engineering strategies. Induced pluripotent cells are an attractive alternative to serve as a cell source for tissue engineering applications due to their pluripotency, the potentiality to generate autologous transplantation, and for their high proliferation rate. Among the main liver tissue engineering technologies, 3D bioprinting, hepatic organoids, and decellularization/recellularization of biological matrixes have grown much attention as alternatives to derive functional liver grafts. Thus, this chapter will discuss how recent publications have demonstrated the use of induced pluripotent cells in the development of the aforementioned technologies. Bioprinting is an additive manufacturing biofabrication process where cells are dispersed within a matrix formulation (i.e., bioink) and extruded in a modified 3D-printer. Polymers within bioink can be cross-linked to increase stiffness. Hepatic spheroids showed greater viability and liver function, due to preserved epithelial phenotype over time. Organoid is multi-lineage tissue constructs derived from a stem cell that recapitulates the early stages of organogenesis. The influence of cellular composition of non-parenchymal cells using induced pluripotent-derived cells or primary adult cells for hepatic organoid formation was recently tested. Decellularization is a process where harvested tissues or organs are washed with a detergent-based solution, to lyse and remove all cellular components. The final product is an extracellular scaffold with preserved tissue vasculature and ultra-structure, which can be used for subsequent recellularization with recipient cells. This chapter sheds light on recent works on the use of induced pluripotent-derived cells for liver tissue engineering approaches and on how such technologies could potentially generate therapeutic alternatives for patients on waiting lists for liver transplantation.

Applied Hepatic Bioengineering: Modeling the Human Liver Using Organoid and Liver-on-a-Chip Technologies.

The liver is the most important metabolic hub of endo and xenobiotic compounds. Pre-clinical studies using rodents to evaluate the toxicity of new drugs and cosmetics may produce inconclusive results for predicting clinical outcomes in humans, moreover being banned in the European Union. Human liver modeling using primary hepatocytes presents low reproducibility due to batch-to-batch variability, while iPSC-derived hepatocytes in monolayer cultures (2D) show reduced cellular functionality. Here we review the current status of the two most robust in vitro approaches in improving hepatocyte phenotype and metabolism while mimicking the hepatic physiological microenvironment: organoids and liver-on-chip. Both technologies are reviewed in design and manufacturing techniques, following cellular composition and functionality. Furthermore, drug screening and liver diseases modeling efficiencies are summarized. Finally, organoid and liver-on-chip technologies are compared regarding advantages and limitations, aiming to guide the selection of appropriate models for translational research and the development of such technologies.

Personalized Medicine Using Cutting Edge Technologies for Genetic Epilepsies.

Epilepsy is the most common chronic neurologic disorder in the world, affecting 1-2% of the population. Besides, 30% of epilepsy patients are drug-resistant. Genomic mutations seem to play a key role in its etiology and knowledge of strong effect mutations in protein structures might improve prediction and the development of efficacious drugs to treat epilepsy. Several genetic association studies have been undertaken to examine the effect of a range of candidate genes for resistance. Although, few studies have explored the effect of the mutations into protein structure and biophysics in the epilepsy field. Much work remains to be done, but the plans made for exciting developments will hold therapeutic potential for patients with drug-resistance. In summary, we provide a critical review of the perspectives for the development of individualized medicine for epilepsy based on genetic polymorphisms/mutations in light of core elements such as transcriptomics, structural biology, disease model, pharmacogenomics and pharmacokinetics in a manner to improve the success of trial designs of antiepileptic drugs.

Soluble factors of mesenchimal stem cells (FS-MSC) as a potential tool to reduce inflammation in donor's lungs after hypovolemic shock. / Fatores solúveis de células-tronco mesenquimais (FS-CTM) como uma ferramenta potencial para reduzir a inflamação nos pulmões de doadores após choque hipovolêmico.

OBJECTIVE: The shortage of viable lungs is still a major obstacle for transplantation. Trauma victims who represent potential lung donors commonly present hypovolemic shock leading to pulmonary inflammation and deterioration and rejection after transplantation. Seeking to improve lung graft, new approaches to donor treatment have been tested. This study focuses on treatment with mesenchymal stem cells (MSCs) or soluble factors produced by MSCs (FS-MSC) using a rat model for lung donors after hemorrhagic shock. METHODS: Forty-eight rats were divided into four groups: Sham (n=12), animals without induction of hypovolemic shock; Shock (n=12), animals submitted to hypovolemic shock (mean arterial pressure 40 mmHg); MSC (n=12), animals submitted to hypovolemic shock and treated with MSCs, and FS (n=12), animals submitted to hypovolemic shock and treated with FS-MSC. The animals were subjected to a 50-minute hypovolemic shock (40 mmHg) procedure. The treated animals were monitored for 115 minutes. We performed histopathology of lung tissue and quantification of inflammatory markers (TNF-α, IL-1ß, IL-6, IL-10, iCAM and vCAM) in lung tissue and peripheral blood leukocytes (PBLs). RESULTS: Hemorrhagic shock resulted in higher PBLs and neutrophil infiltrate in the lungs. FS animals had lower neutrophil density comparing with Shock and MSC animals (p<0.001). No differences in the cytokine levels in lung tissue were observed between the groups. CONCLUSIONS: The lungs of rats submitted to hemorrhagic shock and treated with FS-MSC showed reduced inflammation indicated in a decrease in lung neutrophil infiltrate.

OBJETIVO: A escassez de pulmões viáveis ainda é um grande obstáculo para o transplante. As vítimas de trauma, que constituem potenciais doadores de pulmão, comumente apresentam choque hipovolêmico que acarreta inflamação e deterioração pulmonar e rejeição após o transplante. Buscando melhorar o enxerto pulmonar, testaram-se novas abordagens ao tratamento do doador. Este estudo foca o tratamento com células-tronco mesenquimais (CTMs) ou fatores solúveis produzidos pelas CTMs (FS-CTMs), usando um modelo com ratos para doadores de pulmão após choque hemorrágico. MÉTODOS: Quarenta e oito ratos foram divididos em quatro grupos: Controle (n=12), animais sem indução de choque hipovolêmico; Choque (n=12), animais submetidos a choque hipovolêmico (pressão arterial média de 40 mmHg); CTM (n=12), animais submetidos a choque hipovolêmico e tratados com CTMs; e FS (n=12), animais submetidos a choque hipovolêmico e tratados com FS-CTMs. Os animais foram submetidos a um procedimento de choque hipovolêmico (40 mmHg) com 50 minutos de duração. Os animais tratados foram monitorados por 115 minutos. Realizamos análise histopatológica do tecido pulmonar e quantificação dos marcadores inflamatórios (TNF-α, IL-1ß, IL-6, IL-10, iCAM e vCAM) no tecido pulmonar e leucócitos no sangue periférico (LSPs). RESULTADOS: O choque hemorrágico resultou em taxas mais altas de LSPs e infiltrado de neutrófilos nos pulmões. Os animais do grupo FS apresentaram menor densidade de neutrófilos em comparação com os animais dos grupos Choque e CTM (p<0,001). Não foram observadas diferenças entre os grupos quanto aos níveis de citocinas no tecido pulmonar. CONCLUSÃO: Os pulmões dos ratos submetidos a choque hemorrágico e tratados com FS-CTM apresentaram inflamação reduzida indicada por uma diminuição do infiltrado de neutrófilos nos pulmões.

DNA methylation as a key epigenetic player for hepatoblastoma characterization.

BACKGROUND: Hepatoblastoma (HB) is a rare embryonal liver tumor of children. Although intrinsic biological differences between tumors can affect prognosis, few groups have studied these differences. Given the recent increased attention to epigenetic mechanisms in the genesis and progression of these tumors, we aimed to classify HB samples according to the stages of liver development and DNA methylation machinery. BASIC PROCEDURES: We evaluated the expression of 24 genes associated with DNA methylation and stages of hepatocyte differentiation and global DNA methylation. Using bioinformatics tools and expression data, we propose a stratification model for HB. MAIN FINDINGS: Tumors clustered into three groups that presented specific gene expression profiles of the panel of DNA methylation enzymes and hepatocyte differentiation markers. In addition to reinforcing these embryonal tumors' molecular heterogeneity, we propose that a panel of 13 genes can stratify HBs (TET1, TET2, TET3, DNMT1, DNMT3A, UHRF1, ALB, CYP3A4, TDO2, UGT1A1, AFP, HNF4A, and FOXA2). DNA methylation machinery participates in the characterization of HBs, directly reflected in diverse DNA methylation content. The data suggested that a subset of HBs were similar to differentiated livers, with upregulation of mature hepatocyte markers, decreased expression of DNA methylation enzymes, and higher global methylation levels; these findings might predict worse outcomes. CONCLUSIONS: HBs are heterogeneous tumors. Despite using a small cohort of 21 HB samples, our findings reinforce that DNA methylation is a robust biomarker for this tumor type.

Pre-coating decellularized liver with HepG2-conditioned medium improves hepatic recellularization.

Liver transplantation from compatible donors has been the main therapy available for patients with irreversible hepatic injuries. Due to the increasing shortage of organs suitable for transplantation, tissue engineering technologies are important alternatives or surrogate approaches for the future of human organ transplantations. New bioengineering tools have been designed to produce decellularized organs (i.e. scaffolds) which could be recellularized with human cells. Specifically, there is an unmet need for developing reproducible protocols for inducing better cellular spreading in decellularized liver scaffolds. The aim of the present work was to investigate the possibility to improve liver scaffold recellularization by pre-coating decellularized tissue scaffolds with HepG2-conditioned medium (CM). Furthermore, we evaluated the capability of commercial human liver cells (HepG2) to adhere to several types of extracellular matrices (ECM) as well as CM components. Wistar rat livers were decellularized and analyzed by histology, scanning electron microscopy (SEM), immunohistochemistry and residual DNA-content analysis. Human induced pluripotent stem cells (hiPSCs)-derived mesenchymal cells (hiMSCs), and human commercial hepatic (HepG2) and endothelial (HAEC) cells were used for liver scaffold recellularization with or without CM pre-coating. Recellularization occurred for up to 5 weeks. Hepatic tissues and CM were analyzed by proteomic assays. We show that integrity and anatomical organization of the hepatic ECM were maintained after decellularization, and proteomic analysis suggested that pre-coating with CM enriched the decellularized liver ECM. Pre-coating with HepG2-CM highly improved liver recellularization and revealed the positive effects of liver ECM and CM components association.

Recapitulation of Neural Crest Specification and EMT via Induction from Neural Plate Border-like Cells.

Neural crest cells (NCCs) contribute to several tissues during embryonic development. NCC formation depends on activation of tightly regulated molecular programs at the neural plate border (NPB) region, which initiate NCC specification and epithelial-to-mesenchymal transition (EMT). Although several approaches to investigate NCCs have been devised, these early events of NCC formation remain largely unknown in humans, and currently available cellular models have not investigated EMT. Here, we report that the E6 neural induction protocol converts human induced pluripotent stem cells into NPB-like cells (NBCs), from which NCCs can be efficiently derived. NBC-to-NCC induction recapitulates gene expression dynamics associated with NCC specification and EMT, including downregulation of NPB factors and upregulation of NCC specifiers, coupled with other EMT-associated cell-state changes, such as cadherin modulation and activation of TWIST1 and other EMT inducers. This strategy will be useful in future basic or translational research focusing on these early steps of NCC formation.

Differential gene expression elicited by ZIKV infection in trophoblasts from congenital Zika syndrome discordant twins.

Zika virus (ZIKV) causes congenital Zika syndrome (CZS), which is characterized by fetal demise, microcephaly and other abnormalities. ZIKV in the pregnant woman circulation must cross the placental barrier that includes fetal endothelial cells and trophoblasts, in order to reach the fetus. CZS occurs in ~1-40% of cases of pregnant women infected by ZIKV, suggesting that mothers' infection by ZIKV during pregnancy is not deterministic for CZS phenotype in the fetus. Therefore, other susceptibility factors might be involved, including the host genetic background. We have previously shown that in three pairs of dizygotic twins discordant for CZS, neural progenitor cells (NPCs) from the CZS-affected twins presented differential in vitro ZIKV susceptibility compared with NPCs from the non-affected. Here, we analyzed human-induced-pluripotent-stem-cell-derived (hiPSC-derived) trophoblasts from these twins and compared by RNA-Seq the trophoblasts from CZS-affected and non-affected twins. Following in vitro exposure to a Brazilian ZIKV strain (ZIKVBR), trophoblasts from CZS-affected twins were significantly more susceptible to ZIKVBR infection when compared with trophoblasts from the non-affected. Transcriptome profiling revealed no differences in gene expression levels of ZIKV candidate attachment factors, IFN receptors and IFN in the trophoblasts, either before or after ZIKVBR infection. Most importantly, ZIKVBR infection caused, only in the trophoblasts from CZS-affected twins, the downregulation of genes related to extracellular matrix organization and to leukocyte activation, which are important for trophoblast adhesion and immune response activation. In addition, only trophoblasts from non-affected twins secreted significantly increased amounts of chemokines RANTES/CCL5 and IP10 after infection with ZIKVBR. Overall, our results showed that trophoblasts from non-affected twins have the ability to more efficiently activate genes that are known to play important roles in cell adhesion and in triggering the immune response to ZIKV infection in the placenta, and this may contribute to predict protection from ZIKV dissemination into fetuses' tissues.

Long-term single-cell passaging of human iPSC fully supports pluripotency and high-efficient trilineage differentiation capacity.

OBJECTIVES: To establish a straightforward single-cell passaging cultivation method that enables high-quality maintenance of human induced pluripotent stem cells without the appearance of karyotypic abnormalities or loss of pluripotency. METHODS: Cells were kept in culture for over 50 passages, following a structured chronogram of passage and monitoring cell growth by population doubling time calculation and cell confluence. Standard procedures for human induced pluripotent stem cells monitoring as embryonic body formation, karyotyping and pluripotency markers expression were evaluated in order to assess the cellular state in long-term culture. Cells that underwent these tests were then subjected to differentiation into keratinocytes, cardiomyocytes and definitive endoderm to evaluate its differentiation capacity. RESULTS: Human induced pluripotent stem cells clones maintained its pluripotent capability as well as chromosomal integrity and were able to generate derivatives from the three germ layers at high passages by embryoid body formation and high-efficient direct differentiation into keratinocytes, cardiomyocytes and definitive endoderm. CONCLUSIONS: Our findings support the routine of human induced pluripotent stem cells single-cell passaging as a reliable procedure even after long-term cultivation, providing healthy human induced pluripotent stem cells to be used in drug discovery, toxicity, and disease modeling as well as for therapeutic approaches.

Adult and iPS-derived non-parenchymal cells regulate liver organoid development through differential modulation of Wnt and TGF-ß.

BACKGROUND: Liver organoid technology holds great promises to be used in large-scale population-based drug screening and in future regenerative medicine strategies. Recently, some studies reported robust protocols for generating isogenic liver organoids using liver parenchymal and non-parenchymal cells derived from induced pluripotent stem cells (iPS) or using isogenic adult primary non-parenchymal cells. However, the use of whole iPS-derived cells could represent great challenges for a translational perspective. METHODS: Here, we evaluated the influence of isogenic versus heterogenic non-parenchymal cells, using iPS-derived or adult primary cell lines, in the liver organoid development. We tested four groups comprised of all different combinations of non-parenchymal cells for the liver functionality in vitro. Gene expression and protein secretion of important hepatic function markers were evaluated. Additionally, liver development-associated signaling pathways were tested. Finally, organoid label-free proteomic analysis and non-parenchymal cell secretome were performed in all groups at day 12. RESULTS: We show that liver organoids generated using primary mesenchymal stromal cells and iPS-derived endothelial cells expressed and produced significantly more albumin and showed increased expression of CYP1A1, CYP1A2, and TDO2 while presented reduced TGF-ß and Wnt signaling activity. Proteomics analysis revealed that major shifts in protein expression induced by this specific combination of non-parenchymal cells are related to integrin profile and TGF-ß/Wnt signaling activity. CONCLUSION: Aiming the translation of this technology bench-to-bedside, this work highlights the role of important developmental pathways that are modulated by non-parenchymal cells enhancing the liver organoid maturation.

TET Upregulation Leads to 5-Hydroxymethylation Enrichment in Hepatoblastoma.

Hepatoblastoma is an embryonal liver tumor carrying few genetic alterations. We previously disclosed in hepatoblastomas a genome-wide methylation dysfunction, characterized by hypermethylation at specific CpG islands, in addition to a low-level hypomethylation pattern in non-repetitive intergenic sequences, in comparison to non-tumoral liver tissues, shedding light into a crucial role for epigenetic dysregulation in this type of cancer. To explore the underlying mechanisms possibly related to aberrant epigenetic modifications, we evaluated the expression profile of a set of genes engaged in the epigenetic machinery related to DNA methylation (DNMT1, DNMT3A, DNMT3B, DNMT3L, UHRF1, TET1, TET2, and TET3), as well as the 5-hydroxymethylcytosine (5hmC) global level. We observed in hepatoblastomas a general disrupted expression of these genes from the epigenetic machinery, mainly UHRF1, TET1, and TET2 upregulation, in association with an enrichment of 5hmC content. Our findings support a model of active demethylation by TETs in hepatoblastoma, probably during early stages of liver development, which in combination with UHRF1 overexpression would lead to DNA hypomethylation and an increase in overall 5hmC content. Furthermore, our data suggest that decreased 5hmC content might be associated with poor survival rate, highlighting a pivotal role of epigenetics in hepatoblastoma development and progression.