Mutant huntingtin impairs neurodevelopment in human brain organoids through CHCHD2-mediated neurometabolic failure.

Expansion of the glutamine tract (poly-Q) in the protein huntingtin (HTT) causes the neurodegenerative disorder Huntington's disease (HD). Emerging evidence suggests that mutant HTT (mHTT) disrupts brain development. To gain mechanistic insights into the neurodevelopmental impact of human mHTT, we engineered male induced pluripotent stem cells to introduce a biallelic or monoallelic mutant 70Q expansion or to remove the poly-Q tract of HTT. The introduction of a 70Q mutation caused aberrant development of cerebral organoids with loss of neural progenitor organization. The early neurodevelopmental signature of mHTT highlighted the dysregulation of the protein coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2), a transcription factor involved in mitochondrial integrated stress response. CHCHD2 repression was associated with abnormal mitochondrial morpho-dynamics that was reverted upon overexpression of CHCHD2. Removing the poly-Q tract from HTT normalized CHCHD2 levels and corrected key mitochondrial defects. Hence, mHTT-mediated disruption of human neurodevelopment is paralleled by aberrant neurometabolic programming mediated by dysregulation of CHCHD2, which could then serve as an early interventional target for HD.

Novel human neurodevelopmental and neurodegenerative disease associated with IRF2BPL gene variants-mechanisms and therapeutic avenues.

Recently a broad range of phenotypic abnormalities related to the neurodevelopmental and neurodegenerative disorder NEDAMSS (Neurodevelopmental Disorder with Regression, Abnormal Movements, Loss of Speech, and Seizures) have been associated with rare single-nucleotide polymorphisms (SNPs) or insertion and deletion variants (Indel) in the intron-less gene IRF2BPL. Up to now, 34 patients have been identified through whole exome sequencing carrying different heterozygous pathogenic variants spanning the intron-less gene from the first polyglutamine tract at the N-terminus to the C3HC4 RING domain of the C-terminus of the protein. As a result, the phenotypic spectrum of the patients is highly heterogeneous and ranges from abnormal neurocognitive development to severe neurodegenerative courses with developmental and seizure-related encephalopathies. While the treatment of IRF2BPL-related disorders has focused on alleviating the patient's symptoms by symptomatic multidisciplinary management, there has been no prospect of entirely relieving the symptoms of the individual patients. Yet, the recent advancement of CRISPR-Cas9-derived gene editing tools, leading to the generation of base editors (BEs) and prime editors (PEs), provide an encouraging new therapeutic avenue for treating NEDAMSS and other neurodevelopmental and neurodegenerative diseases, which contain SNPs or smaller Indels in post-mitotic cell populations of the central nervous system, due to its ability to generate site-specific DNA sequence modifications without creating double-stranded breaks, and recruiting the non-homologous DNA end joining repair mechanism.

Generation of an induced pluripotent stem cell line from a Huntington's disease patient with a long HTT-PolyQ sequence.

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an abnormal length of CAG repeats in the gene HTT, leading to an elongated poly-glutamine (poly-Q) sequence in huntingtin (HTT). We used non-integrative Sendai virus to reprogram fibroblasts from a patient with juvenile onset HD to induced pluripotent stem cells (iPSCs). Reprogrammed iPSCs expressed pluripotency-associated markers, exhibited a normal karyotype, and following directed differentiation generated cell types belonging to the three germ layers. PCR analysis and sequencing confirmed the HD patient-derived iPSC line had one normal HTT allele and one with elongated CAG repeats, equivalent to ≥180Q.

Genome-engineering technologies for modeling and treatment of cystic fibrosis.

Cystic fibrosis (CF) is an autosomal recessive disease caused by defects in the CF transmembrane conductance regulator (CFTR) protein. Due to the genetic nature of the disease, interventions in the genome can target any underlying alterations and potentially provide permanent disease resolution. The current development of gene-editing tools, such as designer nuclease technology capable of genome correction, holds great promise for both CF and other genetic diseases. In recent years, Cas9-based technologies have enabled the generation of genetically defined human stem cell and disease models based on induced pluripotent stem cells (iPSC). In this article, we outline the potential and possibilities of using CRISPR/Cas9-based gene-editing technology in CF modeling.

Mechanisms of IRF2BPL-related disorders and identification of a potential therapeutic strategy.

The recently discovered neurological disorder NEDAMSS is caused by heterozygous truncations in the transcriptional regulator IRF2BPL. Here, we reprogram patient skin fibroblasts to astrocytes and neurons to study mechanisms of this newly described disease. While full-length IRF2BPL primarily localizes to the nucleus, truncated patient variants sequester the wild-type protein to the cytoplasm and cause aggregation. Moreover, patient astrocytes fail to support neuronal survival in coculture and exhibit aberrant mitochondria and respiratory dysfunction. Treatment with the small molecule copper ATSM (CuATSM) rescues neuronal survival and restores mitochondrial function. Importantly, the in vitro findings are recapitulated in vivo, where co-expression of full-length and truncated IRF2BPL in Drosophila results in cytoplasmic accumulation of full-length IRF2BPL. Moreover, flies harboring heterozygous truncations of the IRF2BPL ortholog (Pits) display progressive motor defects that are ameliorated by CuATSM treatment. Our findings provide insights into mechanisms involved in NEDAMSS and reveal a promising treatment for this severe disorder.

Generation of induced pluripotent stem cells from three individuals with Huntington's disease.

Huntington's disease (HD) is a neurodegenerative disorder caused by abnormal glutamine (Q) expansion in the huntingtin protein due to elongated CAG repeats in the gene HTT. We used non-integrative episomal plasmids to generate induced pluripotent stem cells (iPSCs) from three individuals affected by HD: CH1 (58Q), and two twin brothers CH3 (44Q) and CH4 (44Q). The iPSC lines exhibited one healthy HTT allele and one with elongated CAG repeats, as confirmed by PCR and sequencing. All iPSC lines expressed pluripotency markers, exhibited a normal karyotype, and generated cells of the three germ layers in vitro.

Moderate Effects of School-Based Time Increasing Physical Education Intervention on Physical Fitness and Activity of 7-Year Pupils-A Report from a Follow-Up of a HCSC Study.

We evaluated the effectiveness of a 15-week intervention that increased from three to five lessons of physical education (PE) a week on 7-year-old boys' and girls' physical fitness (PF), physical activity (PA) and sedentary behaviour on week and weekend days. A total of 212 first grade pupils (mean age 6.95 ± 0.43) from two urban schools in Poznan were randomly assigned to the experimental or control groups. The PF was measured with a battery of field tests, while health-related behaviours were assessed with the Healthy Children in Sound Communities questionnaire. There were some interaction effects noticed in the PF scores in the case of a 20-min run for boys (F2,196 = 5.29, p = 0.0058) and for girls (F2,220 = 3.31, p = 0.0382) and the sit-ups test for boys (F2,196 = 1.93, p = 0.1478) and for girls (F2,220 = 3.98, p = 0.0201) and for the sit and reach test in the case of girls (F2,220 = 3.98, p = 0.0201). In terms of outdoor PA levels, there were no major differences between any of the examined groups. Differences were found between girls from the experimental and control groups in the post-test (p = 0.0107) and follow-up (p = 0.0390) during the weekdays, with no differences between the groups of boys. Despite the moderate effects of the extended PE time programme right after the intervention, there were some indications of progress in the follow-up experiments.

Deletion in the Y chromosome of B10.BR-Ydel mice alters transcription from MSYq genes and has moderate effect on DNA methylation.

B10.BR-Ydel male mice with large deletion in the male-specific region of the Y chromosome long arm (MSYq) are very useful experimental model which requires, however, more detailed characterization. In the present study, the influence of the deletion on transcript levels of MSYq genes (Ssty1, Ssty2, Sly, Srsy, Asty, Orly) and homologous to them X-linked genes (Sstx, Slx, Slxl1, Srsx) was assessed. Quantitative PCR analysis showed that in testes of B10.BR-Ydel males activity of Ssty1 is unchanged, but transcription from all other MSYq genes is highly reduced and reaches from 59 % to only 5 % of the control levels. The decrease in expression of MSYq genes is accompanied by the two-fold increase in expression of Slx and Slxl1 genes. This is the first functional characterization of the deletion in B10.BR-Ydel strain. Another aim of the study was to reveal the mechanism through which deleted Y chromosome of B10.BR-Ydel males could alter phenotype of their female progeny, what was documented in our previous works. Epigenetic inheritance hypothesis was tested by microarray analysis of DNA methylation in B10.BR-Ydel and control B10.BR sperm. The assessment revealed moderate differences and allowed concluding that the mutated Y chromosome can influence traits of females from the next generation partially through altering sperm DNA methylation, but probably some additional mechanisms are engaged here. Breeding data indicate that feminization of pre- and neonatal environment in which next generation females develop is one of such additional mechanisms.

Generation of Human iPSC-derived Neural Progenitor Cells (NPCs) as Drug Discovery Model for Neurological and Mitochondrial Disorders.

The high attrition rate in drug development processes calls for additional human-based model systems. However, in the context of brain disorders, sampling live neuronal cells for compound testing is not applicable. The use of human induced pluripotent stem cells (iPSCs) has revolutionized the field of neuronal disease modeling and drug discovery. Thanks to the development of iPSC-based neuronal differentiation protocols, including tridimensional cerebral organoids, it is now possible to molecularly dissect human neuronal development and human brain disease pathogenesis in a dish. These approaches may allow dissecting patient-specific treatment efficacy in a disease-relevant cellular context. For drug discovery approaches, however, a highly reproducible and cost-effective cell model is desirable. Here, we describe a step-by-step process for generating robust and expandable neural progenitor cells (NPCs) from human iPSCs. NPCs generated with this protocol are homogeneous and highly proliferative. These features make NPCs suitable for the development of high-throughput compound screenings for drug discovery. Human iPSC-derived NPCs show a metabolism dependent on mitochondrial activity and can therefore be used also to investigate neurological disorders in which mitochondrial function is affected. The protocol covers all steps necessary for the preparation, culture, and characterization of human iPSC-derived NPCs. Graphic abstract: Schematic of the protocol for the generation of human iPSC-derived NPCs.

Defective metabolic programming impairs early neuronal morphogenesis in neural cultures and an organoid model of Leigh syndrome.

Leigh syndrome (LS) is a severe manifestation of mitochondrial disease in children and is currently incurable. The lack of effective models hampers our understanding of the mechanisms underlying the neuronal pathology of LS. Using patient-derived induced pluripotent stem cells and CRISPR/Cas9 engineering, we developed a human model of LS caused by mutations in the complex IV assembly gene SURF1. Single-cell RNA-sequencing and multi-omics analysis revealed compromised neuronal morphogenesis in mutant neural cultures and brain organoids. The defects emerged at the level of neural progenitor cells (NPCs), which retained a glycolytic proliferative state that failed to instruct neuronal morphogenesis. LS NPCs carrying mutations in the complex I gene NDUFS4 recapitulated morphogenesis defects. SURF1 gene augmentation and PGC1A induction via bezafibrate treatment supported the metabolic programming of LS NPCs, leading to restored neuronal morphogenesis. Our findings provide mechanistic insights and suggest potential interventional strategies for a rare mitochondrial disease.

Are There Any Differences between First Grade Boys and Girls in Physical Fitness, Physical Activity, BMI, and Sedentary Behavior? Results of HCSC Study.

The transition from kindergarten to school is associated with a variety of negative changes. After entry to elementary school physical activity level decreases. Moreover, physical fitness level of children over the past decades have rapidly declined. Children are spending an increasing amount of time in the environments that require constant sitting. We evaluated the differences between boys and girls in physical fitness, frequency of undertaking of different forms of physical activity, prevalence of underweight and overweight, and time spent on sedentary behavior. A total of 212 first grade pupils (mean age 6.95 ± 0.43) from two standard urban schools in Poznan participated in the study. Compared to girls, boys obtained better results in 20-meter run (4.9 s and 5.0 s, p < 0.01), sit-ups (16.8 and 15.3, p < 0.05), six-minute run (829.7 m and 766.4 m, p < 0.001), and standing broad jump (106.8 cm and 99.7 cm, p < 0.01). In the sit-and-reach test girls achieved higher results than boys (17.0 cm and 14.4 cm, p < 0.001). There were no gender differences in prevalence of underweight and overweight. In conclusions, difference between genders should be taken into consideration during designing physical activity programs in the aspects of intensity and forms of physical activities.

Sirtuin 2-mediated deacetylation of cyclin-dependent kinase 9 promotes STAT1 signaling in type I interferon responses.

Type I interferons (IFNs) induce expression of multiple genes that control innate immune responses to invoke both antiviral and antineoplastic activities. Transcription of these interferon-stimulated genes (ISGs) occurs upon activation of the canonical Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathways. Phosphorylation and acetylation are both events crucial to tightly regulate expression of ISGs. Here, using mouse embryonic fibroblasts and an array of biochemical methods including immunoblotting and kinase assays, we show that sirtuin 2 (SIRT2), a member of the NAD-dependent protein deacetylase family, is involved in type I IFN signaling. We found that SIRT2 deacetylates cyclin-dependent kinase 9 (CDK9) in a type I IFN-dependent manner and that the CDK9 deacetylation is essential for STAT1 phosphorylation at Ser-727. We also found that SIRT2 is subsequently required for the transcription of ISGs and for IFN-driven antiproliferative responses in both normal and malignant cells. These findings establish the existence of a previously unreported signaling pathway whose function is essential for the control of JAK-STAT signaling and the regulation of IFN responses. Our findings suggest that targeting sirtuin activities may offer an avenue in the development of therapies for managing immune-related diseases and cancer.

Novel calcineurin A (PPP3CA) variant associated with epilepsy, constitutive enzyme activation and downregulation of protein expression.

PPP3CA encodes calmodulin-binding catalytic subunit of calcineurin, a ubiquitously expressed calcium/calmodulin-regulated protein phosphatase. Recently de novo PPP3CA variants were reported as a cause of disease in 12 subjects presenting with epileptic encephalopathy and dysmorphic features. We describe a boy with similar phenotype and severe early onset epileptic encephalopathy in whom a novel de novo c.1324C>T (p.(Gln442Ter)) PPP3CA variant was found by whole exome sequencing. Western blot experiments in patient's cells (EBV transformed lymphocytes and neuronal cells derived through reprogramming) indicate that despite normal mRNA abundance the protein expression level is strongly reduced both for the mutated and wild-type protein. By in vitro studies with recombinant protein expressed in E. coli we show that c.1324C>T (p.(Gln442Ter)) results in constitutive activation of the enzyme. Our results confirm the role of PPP3CA defects in pathogenesis of a distinct neurodevelopmental disorder including severe epilepsy and dysmorphism and provide further functional clues regarding the pathogenic mechanism.

The CRISPR/Cas9 system sheds new lights on the biology of protozoan parasites.

The CRISPR/Cas9 system, a natural defence system of bacterial organisms, has recently been used to modify genomes of the most important protozoa parasites. Successful genome manipulations with the CRISPR/Cas9 system are changing the present view of genetics in parasitology. The application of this system offers a major chance to overcome the current restriction in culturing, maintaining and analysing protozoan parasites, and allows dynamic analysis of parasite genes functions, leading to a better understanding of pathogenesis. CRISPR/Cas9 system will have a significant influence on the process of developing novel drugs and treatment strategies against protozoa parasites.

Mitochondria and the dynamic control of stem cell homeostasis.

The maintenance of cellular identity requires continuous adaptation to environmental changes. This process is particularly critical for stem cells, which need to preserve their differentiation potential over time. Among the mechanisms responsible for regulating cellular homeostatic responses, mitochondria are emerging as key players. Given their dynamic and multifaceted role in energy metabolism, redox, and calcium balance, as well as cell death, mitochondria appear at the interface between environmental cues and the control of epigenetic identity. In this review, we describe how mitochondria have been implicated in the processes of acquisition and loss of stemness, with a specific focus on pluripotency. Dissecting the biological functions of mitochondria in stem cell homeostasis and differentiation will provide essential knowledge to understand the dynamics of cell fate modulation, and to establish improved stem cell-based medical applications.

Correction: A novel biomass-based support (Starbon) for TiO2 hybrid photocatalysts: a versatile green tool for water purification.

[This corrects the article DOI: 10.1039/C3RA43673J.].

Transcriptome profiling of Staphylococci-infected cow mammary gland parenchyma.

BACKGROUND: Genome-wide gene expression profiling allows for identification of genes involved in the defense response of the host against pathogens. As presented here, transcriptomic analysis and bioinformatics tools were applied in order to identify genes expressed in the mammary gland parenchyma of cows naturally infected with coagulase-positive and coagulase-negative Staphylococci. RESULTS: In cows infected with coagulase-positive Staphylococci, being in 1st or 2nd lactation, 1700 differentially expressed genes (DEGs) were identified. However, examination of the 3rd or 4th lactations revealed 2200 DEGs. Gene ontology functional classification showed the molecular functions of the DEGs overrepresented the activity of cytokines, chemokines, and their receptors. In cows infected with coagulase-negative Staphylococci, in the 1st or 2nd lactations 418 DEGs, while in the 3rd or 4th lactations, 1200 DEGs were identified that involved in molecular functions such as protein, calcium ion and lipid binding, chemokine activity, and protein homodimerization. Gene network analysis showed DEGs associated with inflammation, cell migration, and immune response to infection, development of cells and tissues, and humoral responses to infections caused by both types of Staphylococci. CONCLUSION: A coagulase-positive Staphylococci infection caused a markedly stronger host response than that of coagulase-negative, resulting in vastly increased DEGs. A significant increase in the expression of the FOS, TNF, and genes encoding the major histocompatibility complex proteins (MHC) was observed. It suggests these genes play a key role in the synchronization of the immune response of the cow's parenchyma against mastitis-causing bacteria. Moreover, the following genes that belong to several physiological pathways (KEGG pathways) were selected for further studies as candidate genes of mammary gland immune response for use in Marker Assisted Selection (MAS): chemokine signaling pathway (CCL2, CXCL5, HCK, CCR1), cell adhesion molecules (CAMs) pathway (BOLA-DQA2, BOLA-DQA1, F11R, ITGAL, CD86), antigen processing and presentation pathway (CD8A, PDIA3, LGMN, IFI30, HSPA1A), and NOD-like receptor signaling pathway (TNF, IL8, IL18, NFKBIA).

Gene editing and clonal isolation of human induced pluripotent stem cells using CRISPR/Cas9.

Human induced pluripotent stem cells (hiPSCs) represent an ideal in vitro platform to study human genetics and biology. The recent advent of programmable nucleases makes also the human genome amenable to experimental genetics through either the correction of mutations in patient-derived iPSC lines or the de novo introduction of mutations into otherwise healthy iPSCs. The production of specific and sometimes complex genotypes in multiple cell lines requires efficient and streamlined gene editing technologies. In this article we provide protocols for gene editing in hiPSCs. We presently achieve high rates of gene editing at up to three loci using a modified iCRISPR system. This system includes a doxycycline inducible Cas9 and sgRNA/reporter plasmids for the enrichment of transfected cells by fluorescence-activated cell sorting (FACS). Here we cover the selection of target sites, vector construction, transfection, and isolation and genotyping of modified hiPSC clones.

Concise Review: Induced Pluripotent Stem Cell-Based Drug Discovery for Mitochondrial Disease.

High attrition rates and loss of capital plague the drug discovery process. This is particularly evident for mitochondrial disease that typically involves neurological manifestations and is caused by nuclear or mitochondrial DNA defects. This group of heterogeneous disorders is difficult to target because of the variability of the symptoms among individual patients and the lack of viable modeling systems. The use of induced pluripotent stem cells (iPSCs) might significantly improve the search for effective therapies for mitochondrial disease. iPSCs can be used to generate patient-specific neural cell models in which innovative compounds can be identified or validated. Here we discuss the promises and challenges of iPSC-based drug discovery for mitochondrial disease with a specific focus on neurological conditions. We anticipate that a proper use of the potent iPSC technology will provide critical support for the development of innovative therapies against these untreatable and detrimental disorders. Stem Cells 2017;35:1655-1662.