FoxG1 antagonizes neocortical stem cell progression to astrogenesis

Neocortical astrogenesis follows neuronogenesis and precedes oligogenesis. Among key factors dictating its temporal articulation, there are progression rates of pallial stem cells (SCs) towards astroglial lineages as well as activation rates of astrocyte differentiation programs in response to extrinsic gliogenic cues. In this study, we showed that high Foxg1 SC expression antagonizes astrocyte generation, while stimulating SC self-renewal and committing SCs to neuronogenesis. We found that mechanisms underlying this activity are mainly cell autonomous and highly pleiotropic. They include a concerted downregulation of 4 key effectors channeling neural SCs to astroglial fates, as well as defective activation of core molecular machineries implementing astroglial differentiation programs. Next, we found that SC Foxg1 levels specifically decline during the neuronogenic-to-gliogenic transition, pointing to a pivotal Foxg1 role in temporal modulation of astrogenesis. Finally, we showed that Foxg1 inhibits astrogenesis from human neocortical precursors, suggesting that this is an evolutionarily ancient trait

Impact of methylmercury and other heavy metals exposure on neurocognitive function in children of 7 years old: study protocol of the follow-up

BACKGROUND: The extent to which prenatal low-level mercury (Hg) exposure through maternal fish intake and heavy metals exposure affect children neurodevelopment is controversial and may appear in long term. In 2007 a prospective cohort, the Northern Adriatic Cohort II (NAC-II), was established to investigate the association between prenatal Hg exposure from maternal fish consumption and child neurodevelopment. 900 pregnant women were enrolled. 632 and 470 children underwent neurodevelopmental evaluation, respectively, at 18 and 40 months of age. The NAC-II cohort is a part of the Mediterranean cohort in "Public health impact of long-term, low-level, mixed element exposure in susceptible population strata" project.METHODS: This protocol describes the follow-up assessment of the effects of prenatal low level Hg and other heavy metals exposure on the developing nervous system of the children born within the NAC-II and reached the age of 7 years. Child diet components are estimated through a Diet Diary. Child hair and urine are collected for determination of Hg level. In addition, levels of other potentially neurotoxic metals, namely Manganese, Cadmium, Lead, Arsenic and Selenium are also measured in the same matrices.DiscussionThis protocol extends to the first years of schooling age the evaluation of the neurotoxicant effect of Mercury and of the other heavy metals on children's neurodevelopment, adjusting for the potential confounders such as the lifestyles and the social economic status of children's families. Longitudinal analysis of neurodevelopment, assessed in different ages (18, 40 months and 7 years), are performed

Carbamazepine-induced thrombocytopenic purpura in a child: Insights from a genomic analysis

To the Editor, Carbamazepine is an effective anticonvulsant and has a relatively low incidence of adverse effects, although it occasionally causes hema- tologic disorders. We herein describe a patient with carbamazepine- induced thrombocytopenic purpura that was investigated by pharma- cological, immunological and genomic assays

Neuronal dysfunction associated with cholesterol deregulation

Cholesterol metabolism is crucial for cells and, in particular, its biosynthesis in the central nervous system occurs in situ, and its deregulation involves morphological changes that cause functional variations and trigger programmed cell death. The pathogenesis of rare diseases, such as Mevalonate Kinase Deficiency or Smith–Lemli–Opitz Syndrome, arises due to enzymatic defects in the cholesterol metabolic pathways, resulting in a shortage of downstream products. The most severe clinical manifestations of these diseases appear as neurological defects. Expanding the knowledge of this biological mechanism will be useful for identifying potential targets and preventing neuronal damage. Several studies have demonstrated that deregulation of the cholesterol pathway induces mitochondrial dysfunction as the result of respiratory chain damage. We set out to determine whether mitochondrial damage may be prevented by using protective mitochondria-targeted compounds, such as MitoQ, in a neuronal cell line treated with a statin to induce a biochemical block of the cholesterol pathway. Evidence from the literature suggests that mitochondria play a crucial role in the apoptotic mechanism secondary to blocking the cholesterol pathway. Our study shows that MitoQ, administered as a preventive agent, could counteract the cell damage induced by statins in the early stages, but its protective role fades over time

Peptide inhibitors of bacterial protein synthesis with broad spectrum and SbmA-independent bactericidal activity against clinical pathogens.

Proline-rich antimicrobial peptides (PrAMPs) are promising lead compounds for developing new antimicrobials, however their narrow spectrum of action is limiting. PrAMPs kill bacteria binding to their ribosomes and inhibiting protein synthesis. In this study, 133 derivatives of the PrAMP Bac7(1-16) were synthesized to identify the crucial residues for ribosome inactivation and antimicrobial activity. Then, five new Bac7(1-16) derivatives were conceived and characterized by antibacterial and membrane permeabilization assays, by X-ray crystallography and molecular dynamics simulations. Some derivatives displayed broad spectrum activity, encompassing Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa and Staphylococcus aureus. Two peptides out of five, acquired a weak membrane-perturbing activity, while maintaining the ability to inhibit protein synthesis. These derivatives became independent of the SbmA transporter, commonly used by native PrAMPs, suggesting that they obtained a novel route to enter bacterial cells. PrAMP-derived compounds could become new-generation antimicrobials to combat the antibiotic-resistant pathogens

Type I interferon-mediated autoinflammation due to DNase II deficiency

Microbial nucleic acid recognition serves as the major stimulus to an antiviral response, implying a requirement to limit the misrepresentation of self nucleic acids as non-self and the induction of autoinflammation. By systematic screening using a panel of interferon-stimulated genes we identify two siblings and a singleton variably demonstrating severe neonatal anemia, membranoproliferative glomerulonephritis, liver fibrosis, deforming arthropathy and increased anti-DNA antibodies. In both families we identify biallelic mutations in DNASE2, associated with a loss of DNase II endonuclease activity. We record increased interferon alpha protein levels using digital ELISA, enhanced interferon signaling by RNA-Seq analysis and constitutive upregulation of phosphorylated STAT1 and STAT3 in patient lymphocytes and monocytes. A hematological disease transcriptomic signature and increased numbers of erythroblasts are recorded in patient peripheral blood, suggesting that interferon might have a particular effect on hematopoiesis. These data define a type I interferonopathy due to DNase II deficiency in humans

Immune properties of mesenchymal stem cells obtained from Wharton's jelly

2007/2008Le cellule stromali mesenchimali multipotenti, oggi meglio conosciute come cellule staminali mesenchimali (MSC) sono state isolate per la prima volta dal midollo osseo di ratti e porcellini d’india da Freidenstein et al. e sono state inizialmente descritte come precursori di fibroblasti per la loro somiglianza morfologica a queste cellule. Una decina di anni dopo le MSC furono isolate anche dal midollo osseo umano. Queste cellule, in vitro, si comportano come cellule staminali: sono capaci di autorinnovarsi e differenziano in cellule tipiche della linea mesenchimale, ma non solo, negli ultimi anni è stata dimostrata anche la loro capacità di differenziare in cellule endoteliali e neuronali. Nel midollo osseo le MSC sono rare: rappresentano solo lo 0.001-0.01% delle cellule nucleate, ma sono poi state identificate anche in molti altri tessuti come quello adiposo e muscolare. Queste cellule vengono isolate sfruttando la loro proprietà di aderire alle superfici plastiche e possono essere facilmente espanse in coltura. Sono caratterizzate da una morfologia eterogenea. Si possono infatti distinguere principalmente due popolazioni: una più piccola simile ai fibroblasti e una con un citoplasma più abbondante di forma quadrata che viene per questo denominata a “fazzoletto”. L’immunofenotipo viene descritto come negativo ai marcatori emopoietici (CD14, CD34 e CD45), endoteliali (CD31), all’HLA di classe II e alle molecole costimolatorie (CD80, CD86), e positivo a CD29, CD44, CD73, CD90, CD105 e HLA di classe I. Le MSC possiedono oltre alla capacità differenziativa un’altra importante proprietà: quella immunomodulatrice. Infatti, in vitro, sono capaci di sopprimere la proliferazione cellulare di linfociti attivati. Per questo motivo queste cellule sono considerate le candidate ideali per il trattamento della Graft Versus Host Disease (GVHD) resistente ai trattamenti steroidei. Sono già utilizzate in trials clinici nonostante ci siano ancora alcuni problemi sperimentali da risolvere. Il primo è ottenere, dopo espansione in vitro, un numero di MSC sufficiente per gli usi terapeutici. A questo scopo sono in studio fonti alternative al midollo osseo, quali il cordone ombelicale e il liquido amniotico. Infatti queste cellule vanno incontro dopo una trentina di raddoppiamenti al fenomeno chiamato senescenza replicativa che rallenta e blocca la loro espansione numerica. L’altro problema è trovare un sostituto al siero fetale bovino, fonte di fattori di crescita per l’espansione cellulare, il cui utilizzo viene messo in discussione per il potenziale rischio di trasmissione di infezioni virali e di prioni dagli animali all’uomo. Scopo di questo lavoro è stato quello di isolare le MSC dalla matrice del cordone ombelicale (gelatina di Wharton) e di studiare l’attività immunosoppressiva delle cellule ottenute. Il cordone ombelicale infatti è facilmente ottenibile e contiene cellule biologicamente più giovani di quelle ottenute dal midollo di donatori adulti; in questo senso dovrebbe essere più semplice la loro espansione in coltura. Inoltre abbiamo usato, in combinazione con il siero fetale bovino (FBS), un pool di liquidi follicolari ovarici (LF), ottenuti contestualmente al prelievo degli ovuli da follicoli ovarici di donne sottoposte a fecondazione assistita. In questo studio sono stati utilizzati solo cordoni ombelicali ottenuti in corso di parto cesareo. La gravidanza deve essere stata portata a termine normalmente e il bambino non deve presentare aneuploidie o altre patologie. La vena e le arterie vengono rimosse con un bisturi e il tessuto rimanente viene sminuzzato fino ad ottenere piccoli frammenti che vengono quindi trasferiti in una piastra da 6 pozzetti con del terreno; dopo circa una decina di giorni le prime cellule cominciano a migrare dal tessuto e ad aderire alla plastica. Vengono quindi staccate con tripsina quando raggiungono la confluenza e seminate nei due diversi terreni: quello addizionato di solo FBS e quello addizionato sia di FBS che di LF. Sulle cellule così ottenute è stata analizzata la curva di crescita dimostrando che è possibile ottenere grandi numeri di MSC (> 1x107) con entrambe le condizioni di coltura. L’immunofenotipo è stato analizzato con la citofluorimetria: le cellule sono caratterizzate da un’elevata espressione del CD29, CD73, e HLA di classe I e da un’espressione più variabile del CD105; mentre sono negative al CD34, CD14 e CD45. Non abbiamo rilevato una differenza significativa tra le due condizioni di coltura fatta eccezione per la presenza di una minor variabilità dei valori per le cellule coltivate in terreno contenente FBS e LF. Le cellule coltivate con entrambe le condizioni di coltura sono capaci di compiere il differenziamento in senso adipogenico quando mantenute in terreni con gli appropriati fattori di crescita. In presenza del liquido follicolare le cellule mostrano un maggior numero di vacuoli. Infine abbiamo valutato le capacità immunomodulanti delle cellule isolate. Le MSC coltivate con entrambi i supplementi hanno mostrato una rilevante capacità antiproliferativa, più evidente per le cellule vive rispetto a quelle sottoposte ad irradiazione. La soppressione richiede il contatto cellulare e, diversamente da quanto suggerito in altri lavori, non sembra mediata dalla produzione di HLA-G. Tra le citochine analizzate l’unica prodotta in quantità elevate dalle MSC è risultata l’IL-6. Resta da valutare se il contatto cellulare sia necessario per l’effettiva soppressione o solo per attivare nelle MSC meccanismi di produzione di mediatori solubili.XXI Cicl

Mevalonate Kinase Deficiency and Squalene Synthase Inhibitor (TAK-475): The Balance to Extinguish the Inflammation

: Mevalonate Kinase Deficiency (MKD) is a rare inborn disease belonging to the family of periodic fever syndromes. The MKD phenotype is characterized by systemic inflammation involving multiple organs, including the nervous system. Current anti-inflammatory approaches to MKD are only partially effective and do not act specifically on neural inflammation. According to the new emerging pharmacology trends, the repositioning of drugs from the indication for which they were originally intended to another one can make mechanistic-based medications easily available to treat rare diseases. According to this perspective, the squalene synthase inhibitor Lapaquistat (TAK-475), originally developed as a cholesterol-lowering drug, might find a new indication in MKD, by modulating the mevalonate cholesterol pathway, increasing the availability of anti-inflammatory isoprenoid intermediates. Using an in vitro model for MKD, we mimicked the blockade of the cholesterol pathway and evaluated the potential anti-inflammatory effect of Lapaquistat. The results obtained showed anti-inflammatory effects of Lapaquistat in association with a low blockade of the metabolic pathway, while this effect did not remain with a tighter blockade. On these bases, Lapaquistat could be configured as an effective treatment for MKD's mild forms, in which the residual enzymatic activity is only reduced and not almost completely absent as in the severe forms

New Mechanisms in Autoinflammatory Diseases

New knowledge on the role of RhoA in the modulation of the pyrin inflammasome opened the way to a better understanding of two apparently unrelated autoinflammatory disorders: Familial Mediterranean Fever (FMF; OMIM#249100) and Mevalonate Kinase Deficiency (MKD; OMIM#260920). RhoA (Ras homolog gene family, member A) is a sensor of innate immunity, which transduces signals after binding of bacterial toxins and other danger signals. Recent data showed that the signaling cascade of RhoA is based on the regulation of cytoskeletal microtubules and regulation of pyrin. RhoA functions as an inhibitor of the pyrin inflammasome. Thus, inhibition of RhoA by bacterial stimuli results in activation of pyrin, while activation of RhoA by drugs such as colchicine results in inhibition of pyrin-mediated inflammation. FMF is due to mutations in the pyrin domain that cause a constitutive activation of pyrin. FMF mutations did not completely prevent pyrin from the inhibitory effect from RhoA. Thus, therapeutic approaches to RhoA signaling may play a role in the treatment of the disease. MKD is caused by mutations in mevalonate kinase and correlate with an impaired prenylation of RhoA, which is reflected on a lack of pyrin inhibition and on autoinflammation. The new knowledge on RhoA establishes an unpredicted connection between these two autoinflammatory disorders

Alendronate, a double-edged sword acting in the mevalonate pathway

Aminobisphosphonate aledronate is a compound commonly used clinically for the treatment of osteoporosis and other bone diseases, as a result of it preventing bone resorption. However, in previous years it has also been used to obtain cellular and animal models of a rare genetic disorder termed Mevalonate Kinase Deficiency (MKD). MKD is caused by mutations affecting the mevalonate kinase enzyme, in the cholesterol pathway and alendronate can be used to biochemically mimic the genetic defect as it inhibits farnesyl pyrophosphate synthase in the same pathway. Despite evidence in favor of the inhibition exerted on the mevalonate pathway, there is at least one clinical case of MKD in which alendronate improved not only skeletal and bone fractures, as expected, but also MKD clinical features. Based on this finding, the present study assessed the anti‑inflammatory properties of this aminobisphosphonate in vitro. No anti‑inflammatory effects of alendronate were observed in the in vitro experiments. Since MKD lacks specific treatments, these results may assist scientists and physicians in making the decision as to the most suitable choice of therapeutic compounds for this neglected disease