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Lopes-Cendes, I.

Publications and source records attributed to Lopes-Cendes, I..

10 recordsLinked to original sources

A multimodal single-cell atlas of the adolescent brain reveals gene regulatory networks linking development to disease risk

Adolescence represents a critical window of brain maturation when many neuropsychiatric disorders first emerge, yet the molecular mechanisms driving this developmental period remain incompletely understood. To address this gap, we generated a high-resolution multimodal cell atlas of the developing adolescent brain using paired single-nucleus RNA and ATAC sequencing (snRNA-seq + snATAC-seq) from cortex, hippocampus, and amygdala tissue of six donors aged 6-15 years, profiling 88,658 high-quality nuclei. Integrative analyses identified 36 enhancer-driven gene regulatory networks (eGRNs) with significant age-dependent dynamics in the transition from childhood to adolescence. The majority of adolescence-associated eGRNs were active in oligodendrocytes and their precursors, reflecting active oligodendrogenesis and myelin remodeling during this developmental period. Notably, age-associated cis-regulatory elements were enriched for expression quantitative trait loci (eQTLs) and colocalized with genetic variants linked to both neurodevelopmental and neurodegenerative disorders, suggesting that regulatory networks may be shared across normal adolescent brain development and disease vulnerability. This multimodal cell atlas provides a valuable resource for understanding the human adolescent brain and offers new insights into the molecular origins of neuropsychiatric disorders.

neuroscience↗

Cell type mapping of mild malformations of cortical development with oligodendroglial hyperplasia in epilepsy using single-nucleus multiomics

ObjectiveMild malformations of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE) are brain lesions associated with focal epilepsy and characterized by increased oligodendroglial density, heterotopic neurons, and hypomyelination in the white matter. While previous studies have implicated somatic mutations in the SLC35A2 gene, the cellular and molecular mechanisms underlying MOGHE pathogenesis remain elusive. To address this gap, this study aimed to systematically characterize the cell type composition and molecular alterations of MOGHE lesions at cellular resolution using single-nucleus multiomics profiling. MethodsWe performed single-nucleus multiomics sequencing to obtain paired gene expression and chromatin accessibility profiles of > 31,000 nuclei from gray matter and white matter regions of MOGHE lesions, and compared the results with publicly available neurotypical control datasets. ResultsThe analysis of gray and white matter regions from two MOGHE patients revealed significant cellular composition alterations, including the presence of heterotopic neurons and disease-specific oligodendrocytes populations within the subcortical white matter. MOGHE-specific oligodendrocytes were characterized by the upregulation of synaptic functions and enhanced neuron communication, denoting a possible role in synaptic support and the mediation of glial-neuron interactions in the disease. On the other hand, MOGHE heterotopic neurons were characterized by the upregulation of genes associated with neuronal migration and the Wnt signaling pathway, suggesting a mechanism underlying their atypical localization. SignificanceThis high-resolution cell type mapping of MOGHE lesions in clinical samples unveils neuronal and glial populations affected by the disease, and provides novel insights into the pathophysiological mechanisms of MOGHE. Key PointsO_LIWe provide a multimodal cellular atlas of the human cortical and subcortical regions affected in MOGHE C_LIO_LIMOGHE-associated oligodendrocytes showed upregulation of synaptic functions and enhanced neuron communication C_LIO_LINeuronal migration and Wnt signaling are upregulated in MOGHE heterotopic neurons C_LI

neuroscience↗

EPILEPTOGENESIS INHIBITS THE CIRCADIAN CLOCK AND RESHAPES THE DIURNAL TRANSCRIPTOMIC RHYTHMICITY IN THE MOUSE HIPPOCAMPUS

Epileptogenesis is the process that leads the brain into epileptic activity. Clinical evidence shows that [~]90% of people with epilepsy present rhythmicity in the timing of their seizures presentation. However, whether the circadian clock is a key player during epileptogenesis remains unknown. Here, we triggered epileptogenesis in mice by the intra-amygdala injection of kainic acid and profiled by RNA sequencing their hippocampal diurnal mRNA rhythmicity. We show that epileptogenesis largely reshapes the hippocampal transcriptomic rhythmicity and that the molecular clock machinery is inhibited due to the disruption of the core clock gene Bmal1. We identified relevant dysregulated pathways and their dynamics in epileptogenesis, predicting a key role for microglial-driven neuroinflammation. We predicted the genes that Bmal1 is directly controlling over time. Finally, we sought for translational relevance evidence by performing RNA sequencing in hippocampal samples resected from patients with mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE-HS) and cross-analyzing datasets.

neuroscience↗

Multimodal single-cell sequencing of the human cortex reveals neuronal vulnerability and activated glial cell states in focal cortical dysplasia

Focal Cortical Dysplasia (FCD) is a neurodevelopmental condition characterized by malformations of the cerebral cortex that often cause drug-resistant epilepsy. In this study, we performed multi-omics single-cell profiling to map the chromatin accessibility and transcriptome landscapes of FCD type II, generating a comprehensive multimodal single-cell dataset comprising 61,525 cells from 11 clinical samples of lesions and controls. Our findings revealed profound chromatin, transcriptomic, and cellular alterations affecting neuronal and glial cells in FCD lesions, including the selective loss of upper-layer excitatory neurons, significant expansion of oligodendrocytes and immature astrocytic populations, and a unique neuronal subpopulation harboring dysmorphic neurons. Furthermore, we uncovered activated microglia subsets, particularly in FCD IIb cases. This comprehensive study unveils neuronal and glial cell states driving FCD development and epileptogenicity, enhancing our understanding of FCD and offering new directions for targeted therapy development.

neuroscience↗

Identifying cellular markers of focal cortical dysplasia type II with cell-type deconvolution and single-cell signatures

Focal cortical dysplasia (FCD) is a brain malformation that causes medically refractory epilepsy. FCD is classified into three categories based on structural and cellular abnormalities, with FCD type II being the most common and characterized by disrupted organization of the cortex and abnormal neuronal development. In this study, we employed cell-type deconvolution and single-cell signatures to analyze bulk RNA-seq from multiple transcriptomic studies, aiming to characterize the cellular composition of brain lesions in patients with FCD IIa and IIb subtypes. Our deconvolution analyses revealed specific cellular changes in FCD IIb, including neuronal loss and an increase in reactive astrocytes (astrogliosis) when compared to FCD IIa. Astrogliosis in FCD IIb was further supported by a gene signature analysis and histologically confirmed by glia fibrilla acidic protein (GAP) immunostaining. Overall, our findings demonstrate that FCD II subtypes exhibit differential neuronal and glial compositions, with astrogliosis emerging as a hallmark of FCD IIb. These observations, validated in independent patient cohorts and confirmed using immunohistochemistry, offer novel insights into the involvement of glial cells in FCD type II pathophysiology and may contribute to the development of targeted therapies for this condition.

neuroscience↗

The transcriptome of rat hippocampal subfields

The hippocampus comprises several neuronal populations such as CA1, CA2, CA3, and the dentate gyrus (DG), which present different neuronal origins, morphologies, and molecular mechanisms. Laser capture microdissection (LCM) allows selectively collecting samples from target regions and eliminating unwanted cells to obtain more specific results. LCM of hippocampus neuronal populations coupled with RNA-seq analysis has the potential to allow the exploration of the molecular machinery unique to each of these subfields. Previous RNA-seq investigation has already provided a molecular blueprint of the hippocampus, however, there is no RNA-seq data specific for each of the rat hippocampal regions. Serial tissue sections covering the hippocampus were produced from frozen brains of adult male Wistar rats, and the hippocampal subfields CA1, CA2, CA3, and DG were identified and isolated by LCM. Total RNA was extracted from samples, and cDNA libraries were prepared and run on a HiSeq 2500 platform. Reads were aligned using STAR, and the DESeq2 statistics package was used to estimate gene expression. We found evident segregation of the transcriptomic profile from different regions of the hippocampus and the expression of known, as well as novel, specific marker genes for each region. Gene ontology enrichment analysis of CA1 subfield indicates an enrichment of actin regulation and postsynaptic membrane AMPA receptors genes indispensable for long-term potentiation. CA2 and CA3 transcripts were found associated with the increased metabolic processes. DG expression was enriched for ribosome and spliceosome, both required for protein synthesis and maintenance of cell life. The present findings contribute to a deeper understanding of the differences in the molecular machinery expressed by the rat hippocampal neuronal populations, further exploring underlying mechanisms responsible for each subflied specific functions.

neuroscience↗

Transcriptomic analysis of dorsal and ventral subiculum after induction of acute seizures by electric stimulation of the perforant pathway in rats

Preconditioning is a mechanism in which injuries induced by non-lethal hypoxia or seizures trigger cellular resistance to subsequent events. Norwood et al., in a 2010 study, showed that an 8-hour-long period of electrical stimulation of the perforant pathway in rats is required for the induction of hippocampal sclerosis. However, in order to avoid generalized seizures, status epilepticus (SE), and death, a state of resistance to seizures must be induced in the hippocampus by a preconditioning paradigm consisting of 2 daily 30-minute stimulation periods. Due to the importance of the subiculum in the hippocampal formation, this study aims to investigate differential gene expression patterns in the dorsal and ventral subiculum using RNA-sequencing, after induction of a preconditioning protocol by electrical stimulation of the perforant pathway. The dorsal (dSub) and ventral (vSub) subiculum regions were collected by laser-microdissection 24 hours after preconditioning protocol induction in rats. RNA sequencing was performed in a Hiseq 4000 platform, reads were aligned using the STAR and DESEq2 statistics package was used to estimate gene expression. We identified 1176 differentially expressed genes comparing control to preconditioned subiculum regions, 204 genes were differentially expressed in dSub and 972 in vSub. The gene ontology enrichment analysis showed that the most significant common enrichment pathway considering up-regulated genes in dSub and vSub was Cholesterol Biosynthesis. In contrast, the most significant enrichment pathway considering down-regulated genes in vSub was Axon guidance. Our results indicate that preconditioning induces synaptic reorganization, increased cholesterol metabolism, and astrogliosis in both dSub and vSub. Both regions also presented a decrease in glutamatergic transmission, an increase in complement system activation, and increased in GABAergic transmission. The down-regulation of proapoptotic and axon guidance genes in the ventral subiculum suggests that preconditioning induces a neuroprotective environment in this region.

neuroscience↗

Genetic variability in COVID-19-related genes in the Brazilian population

SARS-CoV-2 employs the angiotensin-converting enzyme 2 (ACE2) receptor and the transmembrane serine protease (TMPRSS2) to infect human lung cells. Previous studies have suggested that different host genetic backgrounds in ACE2 and TMPRSS2 could contribute to differences in the rate of infection or severity of COVID-19. Recent studies also showed that variants in 15 genes related to type I interferon immunity to influenza virus could predispose to life-threatening COVID-19 pneumonia. Additional genes (SLC6A20, LZTFL1, CCR9, FYCO1, CXCR6, XCR1, IL6, CTSL, ABO, and FURIN) and HLA alleles have also been implicated in response to infection with SARS-CoV-2. Currently, Brazil has recorded the third-highest number of COVID-19 patients worldwide. We aim to investigate the genetic variation present in COVID-19-related genes in the Brazilian population. We analysed 27 candidate genes and HLA alleles in 954 admixed Brazilian exomes. We used the information available in two public databases (http://www.bipmed.org and http://abraom.ib.usp.br/), and additional exomes from individuals born in southeast Brazil, the region with the highest number of COVID-19 patients in the country. Variant allele frequencies were compared with the 1000 Genomes Project phase 3 (1KGP) and the gnomAD databases. We found 395 non-synonymous variants; of these, 325 were also found in the 1000 Genome Project phase 3 (1KGP) and/or gnomAD. Six of these variants were previously reported as putatively influencing the rate of infection or clinical prognosis for COVID-19. The remaining 70 variants were identified exclusively in the Brazilian sample, with a mean allele frequency of 0.0025. In silico prediction of the impact in protein function revealed that three of these rare variants were pathogenic. Furthermore, we identified HLA alleles that were previously associated with COVID-19 response at loci DQB1 and DRB1. Our results showed genetic variability common to other populations, but also rare and ultra-rare variants exclusively found in the Brazilian population. These findings could potentially lead to differences in the rate of infection or response to infection by SARS-CoV-2 and should be further investigated in patients with the disease.

genetics↗

Impact of gestational low-protein intake on embryonic kidney microRNA expression and in the nephron progenitor cells of the male offspring fetus

Authors have demonstrated that gestational low-protein (LP) intake offspring showed a lower birth weight, reduced nephrons numbers and renal salt excretion, chronic renal failure, and arterial hypertension development when compared to normal (NP) protein intake group in adult life. The current study was aimed to evaluate the miRNAs and predicted gene expression patterns in the fetal kidney at 17 days of gestational (17-DG) protein-restricted male offspring (LP) in an attempt to elucidate the possible molecular pathways and disorders involved in renal cell proliferation and differentiation during kidney development. By NGS and RT-qPCR were identified, 44 differentially expressed miRNAs, which 19 miRNA were up- and 25 downregulated in LP compared to NP offspring metanephros. Among the top 10 deregulated miRNAs, the study selected 7 miRNAs which its biological targets were related to proliferation, differentiation, and cellular apoptosis processes. As could be seen below, both miRNA-Seq and TaqMan data analysis have shown a consistent change of miRNA expression in LP animals relative to control NP age-matched animals. By immunofluorescence, the LP fetus showed a significant 28% reduction of Six-2 labeled cells when compared to NP offspring associated with a reduced percentage of cell number and c-Myc metanephogenic cap and ureter bud immunostained cells in LP relative to NP offspring. Additionally, the Ki-67 labeled area in CM was 48% lesser in LP compared to NP age-matched fetus. On the other hand, in LP, the CM and UB {beta}-catenin marked area were 154 and 85% raised, respectively. Mtor immunoreactivity was also significantly higher in LP CM (139%) and UB (104%) compared to the NP fetus. In the LP offspring, the TGF{beta}-1 in UBs cells staining increased (about 30%). In contrast, Zeb1 metanephros-stained, located in the CM nuclei cells, enhanced 30% in LP and Zeb2 immunofluorescence, although present in whole metanephros structures, was similar in both experimental groups. In conclusion, the present study demonstrates that the miRNAs, mRNAs, and proteins are modified in LP animals with 17 DGs leading to the reduction of the reciprocal induction between CM and UB, and hence the number of nephrons. These findings will facilitate new functional approaches and further studies to elucidate the regulatory mechanisms involved in the processes of proliferation, differentiation, and apoptosis that occurs during renal development.

developmental biology↗

Genome-wide association study identifies genetic factors that modify age at onset in Machado-Joseph disease

Machado-Joseph disease (MJD/SCA3) is the most common form of dominantly inherited ataxia worldwide. The disorder is caused by an expanded CAG repeat in the ATXN3 gene. Past studies have revealed that the length of the expansion partly explains the disease age at onset (AO) variability of MJD, which is confirmed in this study. Using a total of 786 MJD patients from five different geographical origins, a genome-wide association study (GWAS) was conducted to identify additional AO modifying factors that could explain some of the residual AO variability. We identified nine suggestively associated loci (P < 1 x 10-5). These loci were enriched for genes involved in vesicle transport, olfactory signaling, and synaptic pathways. Furthermore, associations between AO and the TRIM29 and RAG genes suggests that DNA repair mechanisms might be implicated in MJD pathogenesis. Our study demonstrates the existence of several additional genetic factors, along with CAG expansion, that may lead to a better understanding of the genotype-phenotype correlation in MJD.

genetics↗