Biology subjects

Pagani, M.

Publications and source records attributed to Pagani, M..

24 records · Page 2Linked to original sources

bioRxiv2019

Acute and repeated intranasal oxytocin differentially modulate brain-wide functional connectivity

Central release of the neuropeptide oxytocin (OXT) modulates neural substrates involved in socio-affective behavior. This property has prompted research into the use of intranasal OXT administration as an adjunctive therapy for brain conditions characterized by social impairment, such as autism spectrum disorders (ASD). However, the neural circuitry and brain-wide functional networks recruited by intranasal OXT administration remain elusive. Moreover, little is known of the neuroadaptive cascade triggered by long-term administration of this peptide at the network level. To address these questions, we applied fMRI-based circuit mapping in adult mice upon acute and repeated (seven-day) intranasal dosing of OXT. We report that acute and chronic OXT administration elicit comparable fMRI activity as assessed with cerebral blood volume mapping, but entail largely different patterns of brain-wide functional connectivity. Specifically, acute OXT administration focally boosted connectivity within key limbic components of the rodent social brain, whereas repeated dosing led to a prominent and widespread increase in functional connectivity, involving a strong coupling between the amygdala and extended cortical territories. Importantly, this connectional reconfiguration was accompanied by a paradoxical reduction in social interaction and communication in wild-type mice. Our results identify the network substrates engaged by exogenous OXT administration, and show that repeated OXT dosing leads to a substantial reconfiguration of brain-wide connectivity, entailing an aberrant functional coupling between cortico-limbic structures involved in socio-communicative and affective functions. Such divergent patterns of network connectivity might contribute to discrepant clinical findings involving acute or long-term OXT dosing in clinical populations.

neuroscience↗

bioRxiv2018

Longitudinal dissection in brain organoids at single cell resolution uncovers the developmental role of GSK3 in human corticogenesis

The regulation of proliferation and polarity of neural progenitors is crucial for the development of the brain cortex, with modes and timings of cell division intimately related to the stereotypical acquisition of layer-specific neuronal identities. Animal studies have implicated glycogen synthase kinase 3 (GSK3) as a pivotal regulator of both proliferation and polarity, yet the functional relevance of its signaling for the unique features of human corticogenesis remain to be elucidated. Here we harness human cortical brain organoids to probe, at single cell resolution, the longitudinal impact of GSK3 inhibition through multiple developmental stages. Our results indicate that chronic GSK3 inhibition increases the proliferation of neural progenitors and causes massive derangement of cortical tissue architecture. Surprisingly, single cell transcriptome profiling revealed only a discrete impact on early neurogenesis and uncovered the outer radial glia and the astrogenic lineage as the main GSK3-dependent developmental domains. Through this first single cell-level dissection of the GSK3 regulatory network in human corticogenesis, our work uncovers a remarkably specific conduit between the architecture of progenitor niches and lineage specification.

developmental biology↗

bioRxiv2018

Single cell derived organoids capture the self-renewing subpopulations of metastatic ovarian cancer

High Grade Serous Ovarian cancer (HGSOC) is a major unmet need in oncology, due to its precocious dissemination and the lack of meaningful human models for the investigation of disease pathogenesis in a patient-specific manner. To overcome this roadblock, we present a new method to isolate and grow single cells directly from patients ascites, establishing the conditions for propagating them as single-cell derived ovarian cancer organoids (scOCOs). By single cell RNA sequencing (scRNAseq) we define the cellular composition of metastatic ascites and trace its propagation in 2D and 3D culture paradigms, finding that scOCOs retain and amplify key subpopulations from the original patients samples and recapitulate features of the original metastasis that do not emerge from classical 2D culture, including retention of individual patients specificities. By enabling the enrichment of uniquely informative cell subpopulations from HGSOC metastasis and the clonal interrogation of their diversity at the functional and molecular level, this method transforms the prospects of precision oncology for ovarian cancer.

cancer biology↗

bioRxiv2018

Deletion of autism risk gene Shank3 disrupts prefrontal connectivity

Mutations in the synaptic scaffolding protein Shank3 are a major cause of autism, and are associated with prominent intellectual and language deficits. However, the neural mechanisms whereby SHANK3 deficiency affects higher order socio-communicative functions remain unclear. Using high-resolution functional and structural MRI in mice, here we show that loss of Shank3 (Shank3B-/-) results in disrupted local and long-range prefrontal functional connectivity, as well as fronto-striatal decoupling. We document that prefrontal hypo-connectivity is associated with reduced short-range cortical projections density, and reduced gray matter volume. Finally, we show that prefrontal disconnectivity is predictive of social communication deficits, as assessed with ultrasound vocalization recordings. Collectively, our results reveal a critical role of SHANK3 in the development of prefrontal anatomy and function, and suggest that SHANK3 deficiency may predispose to intellectual disability and socio-communicative impairments via dysregulation of higher-order cortical connectivity.

neuroscience↗

bioRxiv2017

Resolving systematic errors in widely-used enhancer activity assays in human cells enables genome-wide functional enhancer characterization

The identification of transcriptional enhancers in the human genome is a prime goal in biology. Enhancers are typically predicted via chromatin marks, yet their function is primarily assessed with plasmid-based reporter assays. Here, we show that two previous observations relating to plasmid-transfection into human cells render such assays unreliable: (1) the function of the bacterial plasmid origin-of-replication (ORI) as a conflicting core-promoter and (2) the activation of a type I interferon (IFN-I) response. These problems cause strongly confounding false-positives and -negatives in luciferase assays and genome-wide STARR-seq screens. We overcome both problems by directly employing the ORI as a core-promoter and by inhibiting two kinases central to IFN-I induction. This corrects luciferase assays and enables genome-wide STARR-seq screens in human cells. Comprehensive enhancer activity profiles in HeLa-S3 cells uncover strong enhancers, IFN-I-induced enhancers, and enhancers endogenously silenced at the chromatin level. Our findings apply to all episomal enhancer activity assays in mammalian cells, and are key to the characterization of human enhancers.

genomics↗

bioRxiv2017

Distinctive Behavioural Anomalies, Structural Brain Phenotypes And Cortical Hyper-Connectivity In Chd8-Deficient Mice

Truncating CHD8 mutations are amongst the highest confidence risk factors for autism spectrum disorders (ASD) identified to date. To investigate how reduced Chd8 gene dosage may disrupt brain development and predispose individuals to ASD, we generated a Chd8 heterozygous mouse model. In line with clinical observations, we found that Chd8 heterozygous mice displayed subtle brain hyperplasia and hypertelorism, coupled with increased postnatal brain weight. Chd8 heterozygous mice displayed anomalous behaviours, but autism-like social deficits, repetitive and restricted behaviours were not present. Only minor gene expression changes were observed in the embryonic neocortex at E12.5, with more pronounced gene expression changes in postnatal cortex at P5. Differentially expressed genes showed highly significant enrichment for known autism candidates. Amongst the down-regulated transcripts, genes involved in cell adhesion and axon guidance were particularly prominent, implicating impaired connectivity as a potential mechanism underlying the ASD phenotype. To probe this further, we performed resting state functional fMRI and found increased synchronised activity in cortico-hippocampal and auditory-parietal networks, hinting at impaired sensory processing. Together, these data show that Chd8 heterozygous mice recapitulate key clinical features found in patients with CHD8 mutations and show a unique combination of behavioural phenotypes, which may be underpinned by a distinctive disruption of brain connectivity and sensory processing.

neuroscience↗