Unraveling the impact of ZZZ3 on the mTOR/ribosome pathway in human embryonic stem cells homeostasis.

Embryonic stem cells (ESCs) are defined as stem cells with self-renewing and differentiation capabilities. These unique properties are tightly regulated and controlled by complex genetic and molecular mechanisms, whose understanding is essential for both basic and translational research. A large number of studies have mostly focused on understanding the molecular mechanisms governing pluripotency and differentiation of ESCs, while the regulation of proliferation has received comparably less attention. Here, we investigate the role of ZZZ3 (zinc finger ZZ-type containing 3) in human ESCs homeostasis. We found that knockdown of ZZZ3 negatively impacts ribosome biogenesis, translation, and mTOR signaling, leading to a significant reduction in cell proliferation. This process occurs without affecting pluripotency, suggesting that ZZZ3-depleted ESCs enter a "dormant-like" state and that proliferation and pluripotency can be uncoupled also in human ESCs.

Ascorbic acid mitigates the impact of oxidative stress in a human model of febrile seizure and mesial temporal lobe epilepsy.

Prolonged febrile seizures (FS) in children are linked to the development of temporal lobe epilepsy (MTLE). The association between these two pathologies may be ascribed to the long-term effects that FS exert on neural stem cells, negatively affecting the generation of new neurons. Among the insults associated with FS, oxidative stress is noteworthy. Here, we investigated the consequences of exposure to hydrogen peroxide (H2O2) in an induced pluripotent stem cell-derived neural stem cells (iNSCs) model of a patient affected by FS and MTLE. In our study, we compare the findings from the MTLE patient with those derived from iNSCs of a sibling exhibiting a milder phenotype defined only by FS, as well as a healthy individual. In response to H2O2 treatment, iNSCs derived from MTLE patients demonstrated an elevated production of reactive oxygen species and increased apoptosis, despite the higher expression levels of antioxidant genes and proteins compared to other cell lines analysed. Among the potential causative mechanisms of enhanced vulnerability of MTLE patient iNSCs to oxidative stress, we found that these cells express low levels of the heat shock protein HSPB1 and of the autophagy adaptor SQSTM1/p62. Pre-treatment of diseased iNSCs with the antioxidant molecule ascorbic acid restored HSBP1 and p62 expression and simultaneously reduced the levels of ROS and apoptosis. Our findings suggest the potential for rescuing the impaired oxidative stress response in diseased iNSCs through antioxidant treatment, offering a promising mechanism to prevent FS degeneration in MTLE.

Insights into the Genetic Profile of Two Siblings Affected by Unverricht-Lundborg Disease Using Patient-Derived hiPSCs.

Unverricht-Lundborg disease (ULD), also known as progressive myoclonic epilepsy 1 (EPM1), is a rare autosomal recessive neurodegenerative disorder characterized by a complex symptomatology that includes action- and stimulus-sensitive myoclonus and tonic-clonic seizures. The main cause of the onset and development of ULD is a repeat expansion of a dodecamer sequence localized in the promoter region of the gene encoding cystatin B (CSTB), an inhibitor of lysosomal proteases. Although this is the predominant mutation found in most patients, the physio-pathological mechanisms underlying the disease complexity remain largely unknown. In this work, we used patient-specific iPSCs and their neuronal derivatives to gain insight into the molecular and genetic machinery responsible for the disease in two Italian siblings affected by different phenotypes of ULD. Specifically, fragment length analysis on amplified CSTB promoters found homozygous status for dodecamer expansion in both patients and showed that the number of dodecamer repeats is the same in both. Furthermore, the luciferase reporter assay showed that the CSTB promoter activity was similarly reduced in both lines compared to the control. This information allowed us to draw important conclusions: (1) the phenotypic differences of the patients do not seem to be strictly dependent on the genetic mutation around the CSTB gene, and (2) that some other molecular mechanisms, not yet clearly identified, might be taken into account. In line with the inhibitory role of cystatin B on cathepsins, molecular investigations performed on iPSCs-derived neurons showed an increased expression of lysosomal cathepsins (B, D, and L) and a reduced expression of CSTB protein. Intriguingly, the increase in cathepsin expression does not appear to be correlated with the residual amount of CSTB, suggesting that other mechanisms, in addition to the regulation of cathepsins, could be involved in the pathological complexity of the disease.

Human iPSC Modeling of Genetic Febrile Seizure Reveals Aberrant Molecular and Physiological Features Underlying an Impaired Neuronal Activity.

Mutations in SCN1A gene, encoding the voltage-gated sodium channel (VGSC) NaV1.1, are widely recognized as a leading cause of genetic febrile seizures (FS), due to the decrease in the Na+ current density, mainly affecting the inhibitory neuronal transmission. Here, we generated induced pluripotent stem cells (iPSCs)-derived neurons (idNs) from a patient belonging to a genetically well-characterized Italian family, carrying the c.434T > C mutation in SCN1A gene (hereafter SCN1AM145T). A side-by-side comparison of diseased and healthy idNs revealed an overall maturation delay of SCN1AM145T cells. Membranes isolated from both diseased and control idNs were injected into Xenopus oocytes and both GABA and AMPA currents were successfully recorded. Patch-clamp measurements on idNs revealed depolarized action potential for SCN1AM145T, suggesting a reduced excitability. Expression analyses of VGSCs and chloride co-transporters NKCC1 and KCC2 showed a cellular "dysmaturity" of mutated idNs, strengthened by the high expression of SCN3A, a more fetal-like VGSC isoform, and a high NKCC1/KCC2 ratio, in mutated cells. Overall, we provide strong evidence for an intrinsic cellular immaturity, underscoring the role of mutant NaV1.1 in the development of FS. Furthermore, our data are strengthening previous findings obtained using transfected cells and recordings on human slices, demonstrating that diseased idNs represent a powerful tool for personalized therapy and ex vivo drug screening for human epileptic disorders.

Microfluidics for 3D Cell and Tissue Cultures: Microfabricative and Ethical Aspects Updates.

The necessity to improve in vitro cell screening assays is becoming ever more important. Pharmaceutical companies, research laboratories and hospitals require technologies that help to speed up conventional screening and therapeutic procedures to produce more data in a short time in a realistic and reliable manner. The design of new solutions for test biomaterials and active molecules is one of the urgent problems of preclinical screening and the limited correlation between in vitro and in vivo data remains one of the major issues. The establishment of the most suitable in vitro model provides reduction in times, costs and, last but not least, in the number of animal experiments as recommended by the 3Rs (replace, reduce, refine) ethical guiding principles for testing involving animals. Although two-dimensional (2D) traditional cell screening assays are generally cheap and practical to manage, they have strong limitations, as cells, within the transition from the three-dimensional (3D) in vivo to the 2D in vitro growth conditions, do not properly mimic the real morphologies and physiology of their native tissues. In the study of human pathologies, especially, animal experiments provide data closer to what happens in the target organ or apparatus, but they imply slow and costly procedures and they generally do not fully accomplish the 3Rs recommendations, i.e., the amount of laboratory animals and the stress that they undergo must be minimized. Microfluidic devices seem to offer different advantages in relation to the mentioned issues. This review aims to describe the critical issues connected with the conventional cells culture and screening procedures, showing what happens in the in vivo physiological micro and nano environment also from a physical point of view. During the discussion, some microfluidic tools and their components are described to explain how these devices can circumvent the actual limitations described in the introduction.

Direct Visualization and Identification of Membrane Voltage-Gated Sodium Channels from Human iPSC-Derived Neurons by Multiple Imaging and Light Enhanced Spectroscopy.

In this study, transmission electron microscopy atomic force microscopy, and surface enhanced Raman spectroscopy are combined through a direct imaging approach, to gather structural and chemical information of complex molecular systems such as ion channels in their original plasma membrane. Customized microfabricated sample holder allows to characterize Nav channels embedded in the original plasma membrane extracted from neuronal cells that are derived from healthy human induced pluripotent stem cells. The identification of the channels is accomplished by using two different approaches, one of them widely used in cryo-EM (the particle analysis method) and the other based on a novel Zernike Polynomial expansion of the images bitmap. This approach allows to carry out a whole series of investigations, one complementary to the other, on the same sample, preserving its state as close as possible to the original membrane configuration.

Uncovering the Metabolic and Stress Responses of Human Embryonic Stem Cells to FTH1 Gene Silencing.

Embryonic stem cells (ESCs) are pluripotent cells with indefinite self-renewal ability and differentiation properties. To function properly and maintain genomic stability, ESCs need to be endowed with an efficient repair system as well as effective redox homeostasis. In this study, we investigated different aspects involved in ESCs' response to iron accumulation following stable knockdown of the ferritin heavy chain (FTH1) gene, which encodes for a major iron storage protein with ferroxidase activity. Experimental findings highlight unexpected and, to a certain extent, paradoxical results. If on one hand FTH1 silencing does not correlate with increased ROS production nor with changes in the redox status, strengthening the concept that hESCs are extremely resistant and, to a certain extent, even refractory to intracellular iron imbalance, on the other, the differentiation potential of hESCs seems to be affected and apoptosis is observed. Interestingly, we found that FTH1 silencing is accompanied by a significant activation of the nuclear factor (erythroid-derived-2)-like 2 (Nrf2) signaling pathway and pentose phosphate pathway (PPP), which crosstalk in driving hESCs antioxidant cascade events. These findings shed new light on how hESCs perform under oxidative stress, dissecting the molecular mechanisms through which Nrf2, in combination with PPP, counteracts oxidative injury triggered by FTH1 knockdown.

Generation of human induced pluripotent stem cell lines (UNIMGi003-A and UNIMGi004-A) from two Italian siblings affected by Unverricht-Lundborg disease.

Unverricht-Lundborg disease (ULD) is an inherited form of progressive myoclonus epilepsy caused by mutations in the gene encoding Cystatin B (CSTB), an inhibitor of lysosomal proteases. The most common mutation described in ULD patients is an unstable expansion of a dodecamer sequence located in the CSTB gene promoter. This expansion is causative of the downregulation of CSTB gene expression and, consequently, of its inhibitory activity. Here we report the generation of induced pluripotent stem cell (iPSC) lines from two Italian siblings having a family history of ULD and affected by different clinical and pathological phenotypes of the disease.

Deciphering the Role of Wnt and Rho Signaling Pathway in iPSC-Derived ARVC Cardiomyocytes by In Silico Mathematical Modeling.

Arrhythmogenic Right Ventricular cardiomyopathy (ARVC) is an inherited cardiac muscle disease linked to genetic deficiency in components of the desmosomes. The disease is characterized by progressive fibro-fatty replacement of the right ventricle, which acts as a substrate for arrhythmias and sudden cardiac death. The molecular mechanisms underpinning ARVC are largely unknown. Here we propose a mathematical model for investigating the molecular dynamics underlying heart remodeling and the loss of cardiac myocytes identity during ARVC. Our methodology is based on three computational models: firstly, in the context of the Wnt pathway, we examined two different competition mechanisms between ß-catenin and Plakoglobin (PG) and their role in the expression of adipogenic program. Secondly, we investigated the role of RhoA-ROCK pathway in ARVC pathogenesis, and thirdly we analyzed the interplay between Wnt and RhoA-ROCK pathways in the context of the ARVC phenotype. We conclude with the following remark: both Wnt/ß-catenin and RhoA-ROCK pathways must be inactive for a significant increase of PPARγ expression, suggesting that a crosstalk mechanism might be responsible for mediating ARVC pathogenesis.

Generation of iPSC lines from two patients affected by febrile seizure due to inherited missense mutation in SCN1A gene.

Here, we described the generation of human induced pluripotent stem cell lines (hiPSCs) from fibroblasts isolated by punch biopsies of two siblings carrying inherited mutation (c.434 T > C) in the SCN1A gene, encoding for the neuronal voltage gated sodium channel NaV1.1. The mutation leads to the substitution of a highly conserved methionine with a threonine (M145T) in the protein sequence, leading to infant febrile seizures (FS). The older brother, affected by complex FS, also developed temporal lobe epilepsy (TLE) during adolescence.

Modeling Cardiac Disease Mechanisms Using Induced Pluripotent Stem Cell-Derived Cardiomyocytes: Progress, Promises and Challenges.

Cardiovascular diseases (CVDs) are a class of disorders affecting the heart or blood vessels. Despite progress in clinical research and therapy, CVDs still represent the leading cause of mortality and morbidity worldwide. The hallmarks of cardiac diseases include heart dysfunction and cardiomyocyte death, inflammation, fibrosis, scar tissue, hyperplasia, hypertrophy, and abnormal ventricular remodeling. The loss of cardiomyocytes is an irreversible process that leads to fibrosis and scar formation, which, in turn, induce heart failure with progressive and dramatic consequences. Both genetic and environmental factors pathologically contribute to the development of CVDs, but the precise causes that trigger cardiac diseases and their progression are still largely unknown. The lack of reliable human model systems for such diseases has hampered the unraveling of the underlying molecular mechanisms and cellular processes involved in heart diseases at their initial stage and during their progression. Over the past decade, significant scientific advances in the field of stem cell biology have literally revolutionized the study of human disease in vitro. Remarkably, the possibility to generate disease-relevant cell types from induced pluripotent stem cells (iPSCs) has developed into an unprecedented and powerful opportunity to achieve the long-standing ambition to investigate human diseases at a cellular level, uncovering their molecular mechanisms, and finally to translate bench discoveries into potential new therapeutic strategies. This review provides an update on previous and current research in the field of iPSC-driven cardiovascular disease modeling, with the aim of underlining the potential of stem-cell biology-based approaches in the elucidation of the pathophysiology of these life-threatening diseases.

A Disposable Passive Microfluidic Device for Cell Culturing.

In this work, a disposable passive microfluidic device for cell culturing that does not require any additional/external pressure sources is introduced. By regulating the height of fluidic columns and the aperture and closure of the source wells, the device can provide different media and/or drug flows, thereby allowing different flow patterns with respect to time. The device is made of two Polymethylmethacrylate (PMMA) layers fabricated by micro-milling and solvent assisted bonding and allows us to ensure a flow rate of 18.6 µl/ℎ - 7%/day, due to a decrease of the fluid height while the liquid is driven from the reservoirs into the channels. Simulations and experiments were conducted to characterize flows and diffusion in the culture chamber. Melanoma tumor cells were used to test the device and carry out cell culturing experiments for 48 hours. Moreover, HeLa, Jurkat, A549 and HEK293T cell lines were cultivated successfully inside the microfluidic device for 72 hours.

Similar miRNomic signatures characterize the follicular fluids collected after follicular and luteal phase stimulations in the same ovarian cycle.

PURPOSE: To detect putative differences in the miRNomic profile of follicular fluids collected after follicular-phase-stimulation (FPS-FFs) and paired luteal-phase-stimulation (LPS-FFs) in the same ovarian cycles (DuoStim). METHODS: Exploratory study at a private IVF center and University involving FPS-FFs and paired-LPS-FFs collected from 15 reduced ovarian reserve and advanced maternal age women undergoing DuoStim (n = 30 paired samples). The samples were combined in 6 paired pools (5 samples each) and balanced according to maternal age and number of cumulus-oocyte-complexes. Micro-RNAs were isolated and sequenced. Four miRNAs were then selected for further validation on 6 single pairs of FPS-FFs and LPS-FFs by qPCR. RESULTS: Forty-three miRNAs were detected in both FPS-FFs and paired-LPS-FFs after sequencing and no statistically significant differences were reported. Thirty-three KEGG pathways were identified as regulated from the detected miRNAs. Four miRNAs (miR-146b, miR-191, miR-320a, and miR-483) were selected for qPCR validation since consistently expressed in our samples and possibly involved in the regulation/establishment of a healthy follicular environment. Again, no significant differences were reported between FPS-FFs and paired-LPS-FFs, also when the analysis was corrected for maternal age and number of cumulus-oocyte-complexes in generalized linear models. CONCLUSIONS: These data complement the embryological, chromosomal, and clinical evidence of equivalence between FPS and LPS published to date.

Stem Cells: The Game Changers of Human Cardiac Disease Modelling and Regenerative Medicine.

A comprehensive understanding of the molecular basis and mechanisms underlying cardiac diseases is mandatory for the development of new and effective therapeutic strategies. The lack of appropriate in vitro cell models that faithfully mirror the human disease phenotypes has hampered the understanding of molecular insights responsible of heart injury and disease development. Over the past decade, important scientific advances have revolutionized the field of stem cell biology through the remarkable discovery of reprogramming somatic cells into induced pluripotent stem cells (iPSCs). These advances allowed to achieve the long-standing ambition of modelling human disease in a dish and, more interestingly, paved the way for unprecedented opportunities to translate bench discoveries into new therapies and to come closer to a real and effective stem cell-based medicine. The possibility to generate patient-specific iPSCs, together with the new advances in stem cell differentiation procedures and the availability of novel gene editing approaches and tissue engineering, has proven to be a powerful combination for the generation of phenotypically complex, pluripotent stem cell-based cellular disease models with potential use for early diagnosis, drug screening, and personalized therapy. This review will focus on recent progress and future outcome of iPSCs technology toward a customized medicine and new therapeutic options.

Establishment and characterization of induced pluripotent stem cells (iPSCs) from central nervous system lupus erythematosus.

Involvement of the central nervous system (CNS) is an uncommon feature in systemic lupus erythematosus (SLE), making diagnosis rather difficult and challenging due to the poor specificity of neuropathic symptoms and neurological symptoms. In this work, we used human-induced pluripotent stem cells (hiPSCs) derived from CNS-SLE patient, with the aim to dissect the molecular insights underlying the disease by gene expression analysis and modulation of implicated pathways. CNS-SLE-derived hiPSCs allowed us to provide evidence of Erk and Akt pathways involvement and to identify a novel cohort of potential biomarkers, namely CHCHD2, IDO1, S100A10, EPHA4 and LEFTY1, never reported so far. We further extended the study analysing a panel of oxidative stress-related miRNAs and demonstrated, under normal or stress conditions, a strong dysregulation of several miRNAs in CNS-SLE-derived compared to control hiPSCs. In conclusion, we provide evidence that iPSCs reprogrammed from CNS-SLE patient are a powerful useful tool to investigate the molecular mechanisms underlying the disease and to eventually develop innovative therapeutic approaches.

Comprehensive proteogenomic analysis of human embryonic and induced pluripotent stem cells.

Although the concepts of somatic cell reprogramming and human-induced pluripotent stem cells (hiPSCs) generation have undergone several analyses to validate the usefulness of these cells in research and clinic, it remains still controversial whether the hiPSCs are equivalent to human embryonic stem cells (hESCs), pointing to the need of further characterization for a more comprehensive understanding of pluripotency. Most of the experimental evidence comes from the transcriptome analysis, while a little is available on protein data, and even less is known about the post-translational modifications. Here, we report a combined strategy of mass spectrometry and gene expression profiling for proteogenomic analysis of reprogrammed and embryonic stem cells. The data obtained through this integrated, multi-"omics" approach indicate that a small, but still significant, number of distinct pathways is enriched in reprogrammed versus embryonic stem cells, supporting the view that pluripotency is an extremely complex, multifaceted phenomenon, with peculiarities that are characteristic of each cell type.

Development of 3D PVA scaffolds for cardiac tissue engineering and cell screening applications.

The aim of this study was the design of a 3D scaffold composed of poly(vinyl) alcohol (PVA) for cardiac tissue engineering (CTE) applications. The PVA scaffold was fabricated using a combination of gas foaming and freeze-drying processes that did not need any cross-linking agents. We obtained a biocompatible porous matrix with excellent mechanical properties. We measured the stress-strain curves of the PVA scaffolds and we showed that the elastic behavior is similar to that of the extracellular matrix of muscles. The SEM observations revealed that the scaffolds possess micro pores having diameters ranging from 10 µm to 370 µm that fit to the dimensions of the cells. A further purpose of this study was to test scaffolds ability to support human induced pluripotent stem cells growth and differentiation into cardiomyocytes. As the proliferation tests show, the number of live stem cells on the scaffold after 12 days was increased with respect to the initial number of cells, revealing the cytocompatibility of the substrate. In addition, the differentiated cells on the PVA scaffolds expressed anti-troponin T, a marker specific of the cardiac sarcomere. We demonstrated the ability of the cardiomyocytes to pulse within the scaffolds. In conclusion, the developed scaffold show the potential to be used as a biomaterial for CTE applications.

The receptor protein tyrosine phosphatase PTPRJ negatively modulates the CD98hc oncoprotein in lung cancer cells.

PTPRJ, a receptor protein tyrosine phosphatase strongly downregulated in human cancer, displays tumor suppressor activity by negatively modulating several proteins involved in proliferating signals. Here, through a proteomic-based approach, we identified a list of potential PTPRJ-interacting proteins and among them we focused on CD98hc, a type II glycosylated integral membrane protein encoded by SLC3A2, corresponding to the heavy chain of a heterodimeric transmembrane amino-acid transporter, including LAT1. CD98hc is widely overexpressed in several types of cancers and contributes to the process of tumorigenesis by interfering with cell proliferation, adhesion, and migration. We first validated PTPRJ-CD98hc interaction, then demonstrated that PTPRJ overexpression dramatically reduces CD98hc protein levels in A549 lung cancer cells. In addition, following to the treatment of PTPRJ-transduced cells with MG132, a proteasome inhibitor, CD98hc levels did not decrease compared to controls, indicating that PTPRJ is involved in the regulation of CD98hc proteasomal degradation. Moreover, PTPRJ overexpression combined with CD98hc silencing consistently reduced cell proliferation and triggered apoptosis of lung cancer cells. Interestingly, by interrogating the can Evolve database, we observed an inverse correlation between PTPRJ and SLC3A2 gene expression. Indeed, the non-small cell lung cancers (NSCLCs) of patients showing a short survival rate express the lowest and the highest levels of PTPRJ and SLC3A2, respectively. Therefore, the results reported here contribute to shed lights on PTPRJ signaling in cancer cells: moreover, our findings also support the development of a novel anticancer therapeutic approach by targeting the pathway of PTPRJ that is usually downregulated in highly malignant human neoplasias.

Two sides of the same coin? Unraveling subtle differences between human embryonic and induced pluripotent stem cells by Raman spectroscopy.

BACKGROUND: Human pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells, hold enormous promise for many biomedical applications, such as regenerative medicine, drug testing, and disease modeling. Although induced pluripotent stem cells resemble embryonic stem cells both morphologically and functionally, the extent to which these cell lines are truly equivalent, from a molecular point of view, remains controversial. METHODS: Principal component analysis and K-means cluster analysis of collected Raman spectroscopy data were used for a comparative study of the biochemical fingerprint of human induced pluripotent stem cells and human embryonic stem cells. The Raman spectra analysis results were further validated by conventional biological assays. RESULTS: Raman spectra analysis revealed that the major difference between human embryonic stem cells and induced pluripotent stem cells is due to the nucleic acid content, as shown by the strong positive peaks at 785, 1098, 1334, 1371, 1484, and 1575 cm-1, which is enriched in human induced pluripotent stem cells. CONCLUSIONS: Here, we report a nonbiological approach to discriminate human induced pluripotent stem cells from their native embryonic stem cell counterparts.

A novel splice variant of the protein tyrosine phosphatase PTPRJ that encodes for a soluble protein involved in angiogenesis.

PTPRJ is a receptor protein tyrosine phosphatase with tumor suppressor activity. Very little is known about the role of PTPRJ ectodomain, although recently both physiological and synthetic PTPRJ ligands have been identified. A putative shorter spliced variant, coding for a 539 aa protein corresponding to the extracellular N-terminus of PTPRJ, is reported in several databases but, currently, no further information is available.Here, we confirmed that the PTPRJ short isoform (named sPTPRJ) is a soluble protein secreted into the supernatant of both endothelial and tumor cells. Like PTPRJ, also sPTPRJ undergoes post-translational modifications such as glycosylation, as assessed by sPTPRJ immunoprecipitation. To characterize its functional activity, we performed an endothelial cell tube formation assay and a wound healing assay on HUVEC cells overexpressing sPTPRJ and we found that sPTPRJ has a proangiogenic activity. We also showed that sPTPRJ expression down-regulates endothelial adhesion molecules, that is a hallmark of proangiogenic activity. Moreover, sPTPRJ mRNA levels in human high-grade glioma, one of the most angiogenic tumors, are higher in tumor samples compared to controls. Further studies will be helpful not only to clarify the way sPTPRJ works but also to supply clues to circumvent its activity in cancer therapy.