Genetic network analysis indicate that individuals affected by neurodevelopmental conditions have genetic variations associated with ophthalmologic alterations: A critical review of literature.

Changes in the nervous system are related to a wide range of mental disorders, which include neurodevelopmental disorders (NDD) that are characterized by early onset mental conditions, such as schizophrenia and autism spectrum disorders and correlated conditions (ASD). Previous studies have shown distinct genetic components associated with diverse schizophrenia and ASD phenotypes, with mostly focused on rescuing neural phenotypes and brain activity, but alterations related to vision are overlooked. Thus, as the vision is composed by the eyes that itself represents a part of the brain, with the retina being formed by neurons and cells originating from the glia, genetic variations affecting the brain can also affect the vision. Here, we performed a critical systematic literature review to screen for all genetic variations in individuals presenting NDD with reported alterations in vision. Using these restricting criteria, we found 20 genes with distinct types of genetic variations, inherited or de novo, that includes SNP, SNV, deletion, insertion, duplication or indel. The variations occurring within protein coding regions have different impact on protein formation, such as missense, nonsense or frameshift. Moreover, a molecular analysis of the 20 genes found revealed that 17 shared a common protein-protein or genetic interaction network. Moreover, gene expression analysis in samples from the brain and other tissues indicates that 18 of the genes found are highly expressed in the brain and retina, indicating their potential role in adult vision phenotype. Finally, we only found 3 genes from our study described in standard public databanks of ophthalmogenetics, suggesting that the other 17 genes could be novel target for vision diseases.

Loss of GTF2I promotes neuronal apoptosis and synaptic reduction in human cellular models of neurodevelopment.

Individuals with Williams syndrome (WS), a neurodevelopmental disorder caused by hemizygous loss of 26-28 genes at 7q11.23, characteristically portray a hypersocial phenotype. Copy-number variations and mutations in one of these genes, GTF2I, are associated with altered sociality and are proposed to underlie hypersociality in WS. However, the contribution of GTF2I to human neurodevelopment remains poorly understood. Here, human cellular models of neurodevelopment, including neural progenitors, neurons, and three-dimensional cortical organoids, are differentiated from CRISPR-Cas9-edited GTF2I-knockout (GTF2I-KO) pluripotent stem cells to investigate the role of GTF2I in human neurodevelopment. GTF2I-KO progenitors exhibit increased proliferation and cell-cycle alterations. Cortical organoids and neurons demonstrate increased cell death and synaptic dysregulation, including synaptic structural dysfunction and decreased electrophysiological activity on a multielectrode array. Our findings suggest that changes in synaptic circuit integrity may be a prominent mediator of the link between alterations in GTF2I and variation in the phenotypic expression of human sociality.

Comment on "Human TKTL1 implies greater neurogenesis in frontal neocortex of modern humans than Neanderthals".

Pinson et al. (1) concluded that the modern human TKTL1 gene is responsible for an increased number of cortical neurons. We show that the "putative Neanderthal variant" of TKTL1 is present in modern human backgrounds. We dispute their argument that this genetic variant is responsible for brain differences in modern humans as opposed to Neanderthals.

IARA: a complete and curated atlas of the biogenesis of spliceosome machinery during RNA splicing.

Splicing is one of the most important post-transcriptional processing systems and is responsible for the generation of transcriptome diversity in all living eukaryotes. Splicing is regulated by the spliceosome machinery, which is responsible for each step of primary RNA processing. However, current molecules and stages involved in RNA splicing are still spread over different studies. Thus, a curated atlas of spliceosome-related molecules and all involved stages during RNA processing can provide all researchers with a reliable resource to better investigate this important mechanism. Here, we present IARA (website access: https://pucpr-bioinformatics.github.io/atlas/), an extensively curated and constantly updated catalog of molecules involved in spliceosome machinery. IARA has a map of the steps involved in the human splicing mechanism, and it allows a detailed overview of the molecules involved throughout the distinct steps of splicing.

Impact of alcohol exposure on neural development and network formation in human cortical organoids.

Prenatal alcohol exposure is the foremost preventable etiology of intellectual disability and leads to a collection of diagnoses known as Fetal Alcohol Spectrum Disorders (FASD). Alcohol (EtOH) impacts diverse neural cell types and activity, but the precise functional pathophysiological effects on the human fetal cerebral cortex are unclear. Here, we used human cortical organoids to study the effects of EtOH on neurogenesis and validated our findings in primary human fetal neurons. EtOH exposure produced temporally dependent cellular effects on proliferation, cell cycle, and apoptosis. In addition, we identified EtOH-induced alterations in post-translational histone modifications and chromatin accessibility, leading to impairment of cAMP and calcium signaling, glutamatergic synaptic development, and astrocytic function. Proteomic spatial profiling of cortical organoids showed region-specific, EtOH-induced alterations linked to changes in cytoskeleton, gliogenesis, and impaired synaptogenesis. Finally, multi-electrode array electrophysiology recordings confirmed the deleterious impact of EtOH on neural network formation and activity in cortical organoids, which was validated in primary human fetal tissues. Our findings demonstrate progress in defining the human molecular and cellular phenotypic signatures of prenatal alcohol exposure on functional neurodevelopment, increasing our knowledge for potential therapeutic interventions targeting FASD symptoms.

SARS-CoV-2 infects human brain organoids causing cell death and loss of synapses that can be rescued by treatment with Sofosbuvir.

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), which was rapidly declared a pandemic by the World Health Organization (WHO). Early clinical symptomatology focused mainly on respiratory illnesses. However, a variety of neurological manifestations in both adults and newborns are now well-documented. To experimentally determine whether SARS-CoV-2 could replicate in and affect human brain cells, we infected iPSC-derived human brain organoids. Here, we show that SARS-CoV-2 can productively replicate and promote death of neural cells, including cortical neurons. This phenotype was accompanied by loss of excitatory synapses in neurons. Notably, we found that the U.S. Food and Drug Administration (FDA)-approved antiviral Sofosbuvir was able to inhibit SARS-CoV-2 replication and rescued these neuronal alterations in infected brain organoids. Given the urgent need for readily available antivirals, these results provide a cellular basis supporting repurposed antivirals as a strategic treatment to alleviate neurocytological defects that may underlie COVID-19- related neurological symptoms.

Response to Comment on "Reintroduction of the archaic variant of NOVA1 in cortical organoids alters neurodevelopment".

Maricic et al. performed an undisclosed in silico­only whole-exome sequencing analysis of our data and found genomic alterations previously undetected in some clones. Some of the predicted alterations, if true, could change the original genotype of the clones. We failed to experimentally validate all but one of these genomic alterations, which did not affect our previous results or data interpretation.

Altered network and rescue of human neurons derived from individuals with early-onset genetic epilepsy.

Early-onset epileptic encephalopathies are severe disorders often associated with specific genetic mutations. In this context, the CDKL5 deficiency disorder (CDD) is a neurodevelopmental condition characterized by early-onset seizures, intellectual delay, and motor dysfunction. Although crucial for proper brain development, the precise targets of CDKL5 and its relation to patients' symptoms are still unknown. Here, induced pluripotent stem cells derived from individuals deficient in CDKL5 protein were used to generate neural cells. Proteomic and phosphoproteomic approaches revealed disruption of several pathways, including microtubule-based processes and cytoskeleton organization. While CDD-derived neural progenitor cells have proliferation defects, neurons showed morphological alterations and compromised glutamatergic synaptogenesis. Moreover, the electrical activity of CDD cortical neurons revealed hyperexcitability during development, leading to an overly synchronized network. Many parameters of this hyperactive network were rescued by lead compounds selected from a human high-throughput drug screening platform. Our results enlighten cellular, molecular, and neural network mechanisms of genetic epilepsy that could ultimately promote novel therapeutic opportunities for patients.

Reintroduction of the archaic variant of NOVA1 in cortical organoids alters neurodevelopment.

The evolutionarily conserved splicing regulator neuro-oncological ventral antigen 1 (NOVA1) plays a key role in neural development and function. NOVA1 also includes a protein-coding difference between the modern human genome and Neanderthal and Denisovan genomes. To investigate the functional importance of an amino acid change in humans, we reintroduced the archaic allele into human induced pluripotent cells using genome editing and then followed their neural development through cortical organoids. This modification promoted slower development and higher surface complexity in cortical organoids with the archaic version of NOVA1 Moreover, levels of synaptic markers and synaptic protein coassociations correlated with altered electrophysiological properties in organoids expressing the archaic variant. Our results suggest that the human-specific substitution in NOVA1, which is exclusive to modern humans since divergence from Neanderthals, may have had functional consequences for our species' evolution.

CitrusKB: a comprehensive knowledge base for transcriptome and interactome of Citrus spp. infected by Xanthomonas citri subsp. citri at different infection stages.

Citrus canker type A is a serious disease caused by Xanthomonas citri subsp. citri (X. citri), which is responsible for severe losses to growers and to the citrus industry worldwide. To date, no canker-resistant citrus genotypes are available, and there is limited information regarding the molecular and genetic mechanisms involved in the early stages of the citrus canker development. Here, we present the CitrusKB knowledge base. This is the first in vivo interactome database for different citrus cultivars, and it was produced to provide a valuable resource of information on citrus and their interaction with the citrus canker bacterium X. citri. CitrusKB provides tools for a user-friendly web interface to let users search and analyse a large amount of information regarding eight citrus cultivars with distinct levels of susceptibility to the disease, with controls and infected plants at different stages of infection by the citrus canker bacterium X. citri. Currently, CitrusKB comprises a reference citrus genome and its transcriptome, expressed transcripts, pseudogenes and predicted genomic variations (SNPs and SSRs). The updating process will continue over time by the incorporation of novel annotations and analysis tools. We expect that CitrusKB may substantially contribute to the field of citrus genomics. CitrusKB is accessible at http://bioinfo.deinfo.uepg.br/citrus. Users can download all the generated raw sequences and generated datasets by this study from the CitrusKB website.

Leaf extracts of Campomanesia xanthocarpa positively regulates atherosclerotic-related protein expression.

Atherosclerosis is caused by a monocyte-mediated inflammatory process that, in turn, is stimulated by cytokines and adhesion molecules. Monocytes are then differentiated into macrophages, leading to the formation of arterial atherosclerotic plaques. Recently, guavirova leaf extracts from Campomanesia xanthocarpa (EG) have shown potential effects on the treatment of plaque formation by reducing cholesterol, LDL levels and serum oxidative stress. We evaluated the effect of EG on the viability of human monocytic and endothelial cell lines at three time points (24, 48 and 72 hours) and whether it can modulate the migration and in vitro expression of CD14, PECAM-1, ICAM-1, HLA-DR and CD105. Cell viability was affected only at higher concentrations and times. We observed decreased ICAM-1 expression in cells treated with 50 µg/ml EG and CD14 expression with IFN-γ and without IFN-γ. CD14 also decreased endothelial cell expression in the presence of IFN-γ and GE. We also found decreased expression of PECAM-1 when treated with EG and IFN-γ. In addition, EG-treated endothelial cells showed higher migration than the control group. Reduced expression of these markers and increased migration may lead to decreased cytokines, which may be contributing to decreased chronic inflammatory response during atherosclerosis and protecting endothelial integrity.

Vertical lossless genomic data compression tools for assembled genomes: A systematic literature review.

The recent decrease in cost and time to sequence and assemble of complete genomes created an increased demand for data storage. As a consequence, several strategies for assembled biological data compression were created. Vertical compression tools implement strategies that take advantage of the high level of similarity between multiple assembled genomic sequences for better compression results. However, current reviews on vertical compression do not compare the execution flow of each tool, which is constituted by phases of preprocessing, transformation, and data encoding. We performed a systematic literature review to identify and compare existing tools for vertical compression of assembled genomic sequences. The review was centered on PubMed and Scopus, in which 45726 distinct papers were considered. Next, 32 papers were selected according to the following criteria: to present a lossless vertical compression tool; to use the information contained in other sequences for the compression; to be able to manipulate genomic sequences in FASTA format; and no need prior knowledge. Although we extracted performance compression results, they were not compared as the tools did not use a standardized evaluation protocol. Thus, we conclude that there's a lack of definition of an evaluation protocol that must be applied by each tool.

The Expression Profile of Dental Pulp-Derived Stromal Cells Supports Their Limited Capacity to Differentiate into Adipogenic Cells.

Mesenchymal stromal cells (MSCs) can self-renew, differentiate into specialised cells and have different embryonic origins-ectodermal for dental pulp-derived MSCs (DPSCs) and mesodermal for adipose tissue-derived MSCs (ADSCs). Data on DPSCs adipogenic differentiation potential and timing vary, and the lack of molecular and genetic information prompted us to gain a better understanding of DPSCs adipogenic differentiation potential and gene expression profile. While DPSCs differentiated readily along osteogenic and chondrogenic pathways, after 21 days in two different types of adipogenic induction media, DPSCs cultures did not contain lipid vacuoles and had low expression levels of the adipogenic genes proliferator-activated receptor gamma (PPARG), lipoprotein lipase (LPL) and CCAAT/enhancer-binding protein alpha (CEBPA). To better understand this limitation in adipogenesis, transcriptome analysis in undifferentiated DPSCs was carried out, with the ADSC transcriptome used as a positive control. In total, 14,871 transcripts were common to DPSCs and ADSCs, some were unique (DPSCs: 471, ADSCs: 1032), and 510 were differentially expressed genes. Detailed analyses of overrepresented transcripts showed that DPSCs express genes that inhibit adipogenic differentiation, revealing the possible mechanism for their limited adipogenesis.

Avoiding the off-target effects of CRISPR/cas9 system is still a challenging accomplishment for genetic transformation.

The recent disclosure of a human embryo subjected to a genetic transformation using the CRISPR/cas9 system give rise to several concerns on ethical questions about its uncontrolled use in humans. Although CRISPR/cas9 has demonstrated its efficiency, this system still lacks the capability to avoid the introduction of undesirable mutations through the target genome. In this Letter, we present several undesirable impacts that CRISPR/cas9 system have in the genetic transformation of the human genome. We briefly discuss, using the very recent literature from distinct high impact journals, the main concerns related to CRISPR/cas9 to deal with off-target effects and how the research community has treated it.

Frequency and association of mitochondrial genetic variants with neurological disorders.

Mitochondria are small cytosolic organelles and the main source of energy production for the cells, especially in the brain. This organelle has its own genome, the mitochondrial DNA (mtDNA), and genetic variants in this molecule can alter the normal energy metabolism in the brain, contributing to the development of a wide assortment of Neurological Disorders (ND), including neurodevelopmental syndromes, neurodegenerative diseases and neuropsychiatric disorders. These ND are comprised by a heterogeneous group of syndromes and diseases that encompass different cognitive phenotypes and behavioral disorders, such as autism, Asperger's syndrome, pervasive developmental disorder, attention deficit hyperactivity disorder, Huntington disease, Leigh Syndrome and bipolar disorder. In this work we carried out a Systematic Literature Review (SLR) to identify and describe the mitochondrial genetic variants associated with the occurrence of ND. Most of genetic variants found in mtDNA were associated with Single Nucleotide Polimorphisms (SNPs), ~79%, with ~15% corresponding to deletions, ~3% to Copy Number Variations (CNVs), ~2% to insertions and another 1% included mtDNA replication problems and genetic rearrangements. We also found that most of the variants were associated with coding regions of mitochondrial proteins but were also found in regulatory transcripts (tRNA and rRNA) and in the D-Loop replication region of the mtDNA. After analysis of mtDNA deletions and CNV, none of them occur in the D-Loop region. This SLR shows that all transcribed mtDNA molecules have mutations correlated with ND. Finally, we describe that all mtDNA variants found were associated with deterioration of cognitive (dementia) and intellectual functions, learning disabilities, developmental delays, and personality and behavior problems.

Author Correction: Blocking Zika virus vertical transmission.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Crosstalk between Hedgehog pathway and energy pathways in human adipose-derived stem cells: A deep sequencing analysis of polysome-associated RNA.

Adult stem cells are considered promising candidates for cellular therapies due to their capacity to differentiate and self-renew. Differentiation leads to changes in the metabolism, structure, and gene expression patterns of cells. Hedgehog is one of the pathways that is involved in the enhancement of osteogenesis and chondrogenesis in adult stem cells, but its mechanisms are poorly understood. In this study, we treated adipose tissue-derived stem cells (ADSC) with two well-characterized drugs, purmorphamine (Hedgehog pathway activator) and cyclopamine (Hedgehog pathway inhibitor), and identified mRNAs associated with polysomes in each treatment group to determine the post transcriptional genetic networks governed by the Hedgehog pathway. Activation of the Hedgehog pathway by purmorphamine results in significant upregulation of mRNAs associated with cellular communication and signal transduction. Furthermore, our experiments show that cyclopamine acts late downregulating GLI1 expression in ADSCs but promotes the upregulation of mRNAs associated with energy pathways and metabolism at early times. Through in silico analysis, we identified some miRNAs, such as miR-355, that could regulate these mRNAs association with polysomes and thereby modulate the Hedgehog pathway. Our results suggest that activation of the Hedgehog pathway by purmorphamine also results in a negative regulation of mRNAs in the protein translation machinery.

Genetic variations on SETD5 underlying autistic conditions.

The prevalence of autism spectrum disorders (ASD) and the number of identified ASD-related genes have increased in recent years. The SETD5 gene encodes a SET-containing-domain 5 protein, a likely reader enzyme. Genetic evidences suggest that SETD5 malfunction contributes to ASD phenotype, such as on intellectual disability (ID) and facial dysmorphism. In this review, we mapped the clinical phenotypes of individuals carrying mutations on the SETD5 gene that are associated with ASD and other chromatinopathies (mutation in epigenetic modifiers that leads to the development of neurodevelopmental disorders such as ASD). After a detailed systematic literature review and analysis of public disease-related databank, we found so far 42 individuals carrying mutations on the SETD5 gene, with 23.8% presenting autistic-like features. Furthermore, most of mutations occurred between positions 9,480,000-9,500,000 bp on chromosome 3 (3p25.3) at the SETD5 gene locus. In all males, mutations in SETD5 presented high penetrance, while in females the clinical phenotype seems more variable with two reported cases showing normal female carriers and not presenting ASD or any ID-like symptoms. At the molecular level, SETD5 interacts with proteins of PAF1C and N-CoR complexes, leading to a possible involvement with chromatin modification pathway, which plays important roles for brain development. Together, we propose that mutations on the SETD5 gene could lead to a new syndromic condition in males, which is linked to 3p25 syndrome, and can leads to ASD-related intellectual disability and facial dysmorphism. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 500-518, 2018.

Blocking Zika virus vertical transmission.

The outbreak of the Zika virus (ZIKV) has been associated with increased incidence of congenital malformations. Although recent efforts have focused on vaccine development, treatments for infected individuals are needed urgently. Sofosbuvir (SOF), an FDA-approved nucleotide analog inhibitor of the Hepatitis C (HCV) RNA-dependent RNA polymerase (RdRp) was recently shown to be protective against ZIKV both in vitro and in vivo. Here, we show that SOF protected human neural progenitor cells (NPC) and 3D neurospheres from ZIKV infection-mediated cell death and importantly restored the antiviral immune response in NPCs. In vivo, SOF treatment post-infection (p.i.) decreased viral burden in an immunodeficient mouse model. Finally, we show for the first time that acute SOF treatment of pregnant dams p.i. was well-tolerated and prevented vertical transmission of the virus to the fetus. Taken together, our data confirmed SOF-mediated sparing of human neural cell types from ZIKV-mediated cell death in vitro and reduced viral burden in vivo in animal models of chronic infection and vertical transmission, strengthening the growing body of evidence for SOF anti-ZIKV activity.

Modeling of TREX1-Dependent Autoimmune Disease using Human Stem Cells Highlights L1 Accumulation as a Source of Neuroinflammation.

Three-prime repair exonuclease 1 (TREX1) is an anti-viral enzyme that cleaves nucleic acids in the cytosol, preventing accumulation and a subsequent type I interferon-associated inflammatory response. Autoimmune diseases, including Aicardi-Goutières syndrome (AGS) and systemic lupus erythematosus, can arise when TREX1 function is compromised. AGS is a neuroinflammatory disorder with severe and persistent intellectual and physical problems. Here we generated a human AGS model that recapitulates disease-relevant phenotypes using pluripotent stem cells lacking TREX1. We observed abundant extrachromosomal DNA in TREX1-deficient neural cells, of which endogenous Long Interspersed Element-1 retrotransposons were a major source. TREX1-deficient neurons also exhibited increased apoptosis and formed three-dimensional cortical organoids of reduced size. TREX1-deficient astrocytes further contributed to the observed neurotoxicity through increased type I interferon secretion. In this model, reverse-transcriptase inhibitors rescued the neurotoxicity of AGS neurons and organoids, highlighting their potential utility in therapeutic regimens for AGS and related disorders.