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Intracerebral hemorrhages are recognized risk factors for neurodevelopmental disorders and represent early biomarkers for cognitive dysfunction and mental disability, but the pathways leading to their occurrence are not well defined. We report that a single intrauterine exposure of the immunostimulant Poly I:C to pregnant mice at gestational day 9, which models a prenatal viral infection and the consequent maternal immune activation, induces the defective formation of brain vessels and causes intracerebral hemorrhagic events, specifically in male offspring. We demonstrate that maternal immune activation promotes the production of the TGF-β1 active form and the consequent enhancement of pSMAD1-5 in males' brain endothelial cells. TGF-β1, in combination with IL-1β, reduces the endothelial expression of CD146 and claudin-5, alters the endothelium-pericyte interplay resulting in low pericyte coverage, and increases hemorrhagic events in the adult offspring. By showing that exposure to Poly I:C at the beginning of fetal cerebral angiogenesis results in sex-specific alterations of brain vessels, we provide a mechanistic framework for the association between intragravidic infections and anomalies of the neural vasculature, which may contribute to neuropsychiatric disorders.

An in vitro blood-brain barrier (BBB) model must be highly reproducible and imitate as much as possible the properties of the in vivo environment, from both the functional and anatomical point of view. In our latest work, a BBB prototype was implemented through the use of human primary brain cells and then integrated in a microfluidic platform (Lauranzano et al., Adv Biosyst 3:e1800335, 2019). Here we describe, step by step, the setting of a customized bio-mimetic platform, which uses human brain endothelial cells and primary astrocytic cells to allow the study of the complex interactions between the immune system and the brain in healthy and neuroinflammatory conditions. The model can be exploited to investigate the neuroimmune communication at the blood-brain interface and to examine the transmigration of patient-derived lymphocytes in order to envisage cutting-edge strategies to restore barrier integrity and block the immune cell influx into the CNS.

Intragravidic and perinatal infections, acting through either direct viral effect or immune‐mediated responses, are recognized causes of liability for neurodevelopmental disorders in the progeny. The large amounts of epidemiological data and the wealth of information deriving from animal models of gestational infections have contributed to delineate, in the last years, possible underpinning mechanisms for this phenomenon, including defects in neuronal migration, impaired spine and synaptic development, and altered activation of microglia. Recently, dysfunctions of the neurovascular unit and anomalies of the brain vasculature have unexpectedly emerged as potential causes at the origin of behavioral abnormalities and psychiatric disorders consequent to prenatal and perinatal infections. This review aims to discuss the up‐to‐date literature evidence pointing to the neurovascular unit and brain vasculature damages as the etiological mechanisms in neurodevelopmental syndromes. We focus on the inflammatory events consequent to intragravidic viral infections as well as on the direct viral effects as the potential primary triggers. These authors hope that a timely review of the literature will help to envision promising research directions, also relevant for the present and future COVID‐19 longitudinal studies., Intragravidic and perinatal infections are recognized causes of liability for neurodevelopmental disorders in the progeny. This review aims to discuss the up‐to‐date evidence pointing to the neurovascular unit and brain vasculature damages as the etiological mechanisms. We focus on the inflammatory events consequent to intragravidic viral infections as well as on the direct viral effects as the potential primary triggers.

Chloride homeostasis, the main determinant factor for the dynamic tuning of GABAergic inhibition during development, has emerged as a key element altered in a wide variety of brain disorders. Accordingly, developmental disorders such as schizophrenia, Autism Spectrum Disorder, Down syndrome, epilepsy, and tuberous sclerosis complex (TSC) have been associated with alterations in the expression of genes codifying for either of the two cotransporters involved in the excitatory-to-inhibitory GABA switch, KCC2 and NKCC1. These alterations can result from environmental insults, including prenatal stress and maternal separation which share, as common molecular denominator, the elevation of pro-inflammatory cytokines. In this review we report and systemize recent research articles indicating that different perinatal environmental perturbations affect the expression of chloride transporters, delaying the developmental switch of GABA signaling, and that inflammatory cytokines, in particular interleukin 1β, may represent a key causal factor for this phenomenon. Based on literature data, we provide therefore a unifying conceptual framework, linking environmental hits with the excitatory-to-inhibitory GABA switch in the context of brain developmental disorders.

SummaryEarly prenatal inflammatory conditions are thought to represent a risk factor for different neurodevelopmental disorders, with long-term consequences on adult brain connectivity. Here we show that a transient IL-6 elevation, occurring at vulnerable stages of early neurodevelopment, directly impacts brain developmental trajectories through the aberrant enhancement of glutamatergic synapses and overall brain hyper-connectivity. The IL6-mediated boost of excitatory synapse density results from the neuron-autonomous, genomic effect of the transcription factor STAT3 and causally involves the activation of RGS4 gene as a candidate downstream target. The STAT3/RGS4 pathway is also activated in neonatal brains as a consequence of maternal immune activation protocols mimicking a viral infection during pregnancy. By demonstrating that prenatal IL-6 elevations result in aberrant synaptic and brain connectivity through the molecular players identified, we provide a mechanistic framework for the association between prenatal inflammatory events and brain neurodevelopmental disorders.

Early prenatal inflammatory conditions are thought to be a risk factor for different neurodevelopmental disorders. Maternal interleukin-6 (IL-6) elevation during pregnancy causes abnormal behavior in offspring, but whether these defects result from altered synaptic developmental trajectories remains unclear. Here we showed that transient IL-6 elevation via injection into pregnant mice or developing embryos enhanced glutamatergic synapses and led to overall brain hyperconnectivity in offspring into adulthood. IL-6 activated synaptogenesis gene programs in glutamatergic neurons and required the transcription factor STAT3 and expression of the RGS4 gene. The STAT3-RGS4 pathway was also activated in neonatal brains during poly(I:C)-induced maternal immune activation, which mimics viral infection during pregnancy. These findings indicate that IL-6 elevation at early developmental stages is sufficient to exert a long-lasting effect on glutamatergic synaptogenesis and brain connectivity, providing a mechanistic framework for the association between prenatal inflammatory events and brain neurodevelopmental disorders.

Bone marrow Mesenchymal Stem Cells (BM-MSCs), due to their strong protective and anti-inflammatory abilities, have been widely investigated in the context of several diseases for their possible therapeutic role, based on the release of a highly proactive secretome composed of soluble factors and Extracellular Vesicles (EVs). BM-MSC-EVs, in particular, convey many of the beneficial features of parental cells, including direct and indirect &beta, amyloid degrading-activities, immunoregulatory and neurotrophic abilities. Therefore, EVs represent an extremely attractive tool for therapeutic purposes in neurodegenerative diseases, including Alzheimer&rsquo, s disease (AD). We examined the therapeutic potential of BM-MSC-EVs injected intracerebrally into the neocortex of APPswe/PS1dE9 AD mice at 3 and 5 months of age, a time window in which the cognitive behavioral phenotype is not yet detectable or has just started to appear. We demonstrate that BM-MSC-EVs are effective at reducing the A&beta, plaque burden and the amount of dystrophic neurites in both the cortex and hippocampus. The presence of Neprilysin on BM-MSC-EVs, opens the possibility of a direct &beta, amyloid degrading action. Our results indicate a potential role for BM-MSC-EVs already in the early stages of AD, suggesting the possibility of intervening before overt clinical manifestations.

Object Bone marrow mesenchymal stem cells (MSC), due to their strong protective and anti-inflammatory abilities, are widely investigated in the context of several diseases for their possible therapeutic role, based on the release of a highly proactive secretome composed of soluble factors and Extracellular Vesicles (EVs). MSC-EVs, in particular, convey many of the beneficial features of parental cells, including direct and indirect β-amyloid degrading-activities, immunoregulatory and neurotrophic abilities. Therefore EVs represent an extremely attractive tool for therapeutic purposes in neurodegenerative diseases, including Alzheimer’s disease (AD). We examined the therapeutic potential of intracerebrally injected MSC-EVs into the neocortex of APP/PS1 mice at 3 and 5 months of age, a time window in which the cognitive behavioral phenotype is not yet detectable or just starts to appear. Materials Primary cultures of Bone Marrow-derived MSC (up to P12 passage), APPswe/PS1dE9 (APP/PS1) AD mice. Methods MSC were stimulated by serum-deprivation for 3 hrs and supernatant was submitted to differential ultracentrifugation to collect EVs (including exosomes and microvesicles pools), which were characterized by Nanoparticle tracking, cryo-EM, flow cytometry and Western blot analysis. APP/PS1 mice, 3 and 5 months old, were injected intracortically with 4 uL of BM-MSC-derived EV suspension, corresponding to 22.4 ug of total proteins. Brain sections of mice treated or not with EVs were immunohistochemically stained for Abeta1-42 peptide (6-E10 antibody). Smi31 and 32 antibodies recognizing Neurofilaments were used for staining dystrophic neurites around Abeta1-42 plaques stained by Thioflavin-T. Results Intracerebral injection of MSC-EVs into the neocortex of APP/PS1 mice at 3 and 5 months of age reduced Abeta1-42 plaques burden one month later compared to same-age untreated mice. At 3 months, when plaques have just started to form, treatment conferred a preventive significance. In addition, following treatment with MSC-EVs, a reduction in dystrophic neurites could been measured. This decrease resulted significantly different in 6 month-old AD mice. Neprilysin, a metal-membrane endopeptidase able to degrade Abeta1-42, was detected on MSC-derived EV lysates. Discussion We demonstrate that MSC-EVs are effective in reducing the Aβ plaque burden and the amount of dystrophic neurites, in both cortex and hippocampus. The presence of Neprilysin on MSC-EVs opens the possibility of a direct β-amyloid degrading-action as a possible mechanisms of action. Conclusions Our results indicate a potential role for MSC-EVs already at early stages of AD, suggesting the possibility to intervene before overt clinical manifestations.

Background Toll-Like Receptors (TLRs) play a critical role in the innate and adaptive immune system. They are the mammalian orthologs of Drosophila melanogaster protein Toll, which has been proved to have an early morphogenetic role in invertebrate embryogenesis that in the adult switches to an immune function. Aim The aim of this study was to evaluate the expression of TLR4 and TLR7 during dorsal root ganglia (DRG), paravertebral ganglia (PVG), and enteric nervous system (ENS) murine development. Methods Mouse embryos from different stages (i.e. E12 to E18) were processed for immunolocalization analysis on formalin-fixed paraffin-embedded sections, and isolated intestine were processed for whole-mount preparations. Results We observed a differentially regulated expression of TLR4 and TLR7 during embryogenesis and an overall increased expression of both receptors during development. While TLR4 was detectable in neurons of DRG and PVG starting from E14 and only from E18 in the ENS, TLR7 was already expressed in scattered neurons of all the investigated regions at E12. Conclusions TLR4 and TRL7 expression temporal patterns suggest a morphogenetic role for these receptors in the development of neural crest derivatives in mammals.

Inflammation modifies risk and/or severity of a variety of brain diseases through still elusive molecular mechanisms. Here we show that hyperactivation of the interleukin 1 pathway, through either ablation of the interleukin 1 receptor 8 (IL-1R8, also known as SIGIRR or Tir8) or activation of IL-1R, leads to up-regulation of the mTOR pathway and increased levels of the epigenetic regulator MeCP2, bringing to disruption of dendritic spine morphology, synaptic plasticity and plasticity-related gene expression. Genetic correction of MeCP2 levels in IL-1R8 KO neurons rescues the synaptic defects. Pharmacological inhibition of IL-1R activation by Anakinra corrects transcriptional changes, restores MeCP2 levels and spine plasticity and ameliorates cognitive defects in IL-1R8 KO mice. By linking for the first time neuronal MeCP2, a key player in brain development, to immune activation and demonstrating that synaptic defects can be pharmacologically reversed, these data open the possibility for novel treatments of neurological diseases through the immune system modulation., Work in our lab is supported by Cariplo 2012–0560, Ministero della Salute GR-2011–02347377, CARIPLO 2015–0594, to MM and by Cariplo 2015–0952 to RT. RT was previously supported by a Fondazione Umberto Veronesi Fellowship. IC is supported by a Fondazione Giancarla Vollaro Fellowship. JPLA is supported by grant SAF2014-60233-JIN from the Ministerio de Economia y Competitividad (MINECO) co-financed by the European Regional Development Fund (ERDF). AB is supported by grants SAF2014-56197-R, SEV-2013-0317 and PCIN-2015-192-C02-01 from MINECO co-financed by the European Regional Development Fund (ERDF). AM acknolewledges a grant from Fondazione Cariplo (Contract n. 2015- 0564.

Background The association between maternal infection and neurodevelopmental defects in progeny is well established, although the biological mechanisms and the pathogenic trajectories involved have not been defined. Methods Pregnant dams were injected intraperitoneally at gestational day 9 with polyinosinic:polycytidylic acid. Neuronal development was assessed by means of electrophysiological, optical, and biochemical analyses. Results Prenatal exposure to polyinosinic:polycytidylic acid causes an imbalanced expression of the Na+-K+-2Cl− cotransporter 1 and the K+-Cl− cotransporter 2 (KCC2). This results in delayed gamma-aminobutyric acid switch and higher susceptibility to seizures, which endures up to adulthood. Chromatin immunoprecipitation experiments reveal increased binding of the repressor factor RE1-silencing transcription (also known as neuron-restrictive silencer factor) to position 509 of the KCC2 promoter that leads to downregulation of KCC2 transcription in prenatally exposed offspring. Interleukin-1 receptor type I knockout mice, which display braked immune response and no brain cytokine elevation upon maternal immune activation, do not display KCC2/Na+-K+-2Cl− cotransporter 1 imbalance when implanted in a wild-type dam and prenatally exposed. Notably, pretreatment of pregnant dams with magnesium sulfate is sufficient to prevent the early inflammatory state and the delay in excitatory-to-inhibitory switch associated to maternal immune activation. Conclusions We provide evidence that maternal immune activation hits a key neurodevelopmental process, the excitatory-to-inhibitory gamma-aminobutyric acid switch; defects in this switch have been unequivocally linked to diseases such as autism spectrum disorder or epilepsy. These data open the avenue for a safe pharmacological treatment that may prevent the neurodevelopmental defects caused by prenatal immune activation in a specific pregnancy time window.

The neurovascular unit (NVU) is the most important biological barrier between vascular districts and central nervous system (CNS) parenchyma, which maintains brain homeostasis, protects the CNS from pathogens penetration, and mediates neuroimmune communication. T lymphocytes migration across the blood-brain barrier is heavily affected in different brain diseases, representing a major target for novel drug development. In vitro models of NVU could represent a primary tool to investigate the molecular events occurring at this interface. To move toward the establishment of personalized therapies, a patient-related NVU-model is set, incorporating human primary astrocytes integrated into a microfluidic platform. The model is morphologically and functionally characterized, proving to be an advantageous tool to investigate human T lymphocytes transmigration and thus the efficacy of potential novel drugs affecting this process.

Substantial data indicate that amyloid-? (A?), the major component of senile plaques, plays a central role in Alzheimer's Disease and indeed the assembly of naturally occurring amyloid peptides into cytotoxic aggregates is linked to the disease pathogenesis. Although A?42 is a highly aggregating form of A?, the co-occurrence of shorter A? peptides might affect the aggregation potential of the A? pool. In this study we aimed to assess whether the structural behavior of human A?42 peptide inside the brain is influenced by the concomitant presence of N-terminal fragments produced by the proteolytic activity of glial cells. We show that the occurrence of the human C-terminal truncated 1-24 A? fragment impairs A?42 clearance through blood brain barrier and promotes the formation of A?42 aggregates even in the healthy brain. By showing that A?1-24 has seeding properties for aggregate formation in intracranially injected wild type mice, our study provide the proof-of-concept that peptides produced upon A?42 cleavage by activated glial cells may cause phenotypic defects even in the absence of genetic mutations associated with Alzheimer's Disease, possibly contributing to the development of the sporadic form of the pathology.

To analyze the effect of three-dimensional (3D)-arrangement on the expression of epithelial-to-mesenchymal transition markers in pancreatic adenocarcinoma (PDAC) cells.HPAF-II, HPAC, and PL45 PDAC cells were cultured in either 2D-monolayers or 3D-spheroids. Ultrastructure was analyzed by transmission electron microscopy. The expression of E-cadherin, β-catenin, N-cadherin, collagen type I (COL-I), vimentin, α-smooth muscle actin (αSMA), and podoplanin was assayed by confocal microscopy in cells cultured on 12-mm diameter round coverslips and in 3D-spheroids. Gene expression for E-cadherin, Snail, Slug, Twist, Zeb1, and Zeb2 was quantified by real-time PCR. E-cadherin protein level and its electrophoretic pattern were studied by Western blot in cell lysates obtained from cells grown in 2D-monolayers and 3D-spheroids.The E-cadherin/β-catenin complex was expressed in a similar way in plasma membrane cell boundaries in both 2D-monolayers and 3D-spheroids. E-cadherin increased in lysates obtained from 3D-spheroids, while cleavage fragments were more evident in 2D-monolayers. N-cadherin expression was observed in very few PDAC cells grown in 2D-monolayers, but was more evident in 3D-spheroids. Some cells expressing COL-I were observed in 3D-spheroids. Podoplanin, expressed in collectively migrating cells, and αSMA were similarly expressed in both experimental conditions. The concomitant maintenance of the E-cadherin/β-catenin complex at cell boundaries supports the hypothesis of a collective migration for these cells, which is consistent with podoplanin expression.We show that a 3D-cell culture model could provide deeper insight into understanding the biology of PDAC and allow for the detection of marked differences in the phenotype of PDAC cells grown in 3D-spheroids.