Faulty neuronal determination and cell polarization are reverted by modulating HD early phenotypes.

Increasing evidence suggests that early neurodevelopmental defects in Huntington's disease (HD) patients could contribute to the later adult neurodegenerative phenotype. Here, by using HD-derived induced pluripotent stem cell lines, we report that early telencephalic induction and late neural identity are affected in cortical and striatal populations. We show that a large CAG expansion causes complete failure of the neuro-ectodermal acquisition, while cells carrying shorter CAGs repeats show gross abnormalities in neural rosette formation as well as disrupted cytoarchitecture in cortical organoids. Gene-expression analysis showed that control organoid overlapped with mature human fetal cortical areas, while HD organoids correlated with the immature ventricular zone/subventricular zone. We also report that defects in neuroectoderm and rosette formation could be rescued by molecular and pharmacological approaches leading to a recovery of striatal identity. These results show that mutant huntingtin precludes normal neuronal fate acquisition and highlights a possible connection between mutant huntingtin and abnormal neural development in HD.

Adipose tissue microbiota in humans: an open issue.

BACKGROUND: A specific 'adipose tissue' microbiota has been recently identified in mice and hypothesized in humans. The purpose of this study was to verify the presence of microbiota of human whole adipose tissue and isolated adipocytes by combining culture-dependent and independent methods. METHODS: Standard microbiological cultural techniques and 16S ribosomal RNA (16S rRNA) gene sequencing (Illumina technology) on DNA and RNA were employed to study (a) whole abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from 14 obese and five normal-weight subjects and (b) mature adipocytes isolated from SAT and VAT after collagenase digestion or mechanical separation. To optimize the 16S rRNA gene detection, we used different DNA extraction methods (lysis with proteinase K, proteinase K+lysozyme and microbeads) and amplification procedures (semi-quantitative standard PCR and real-time quantitative PCR). RESULTS: Microbiological cultures were negative in all analyzed samples. In enzymatically isolated adipocytes, 90% of the sequenced bacterial DNA belonged to Clostridium histolyticum, the bacterium from which the collagenase enzyme was isolated. Bacterial 16S rRNA gene was not detected from DNA and RNA of whole SAT and VAT, as well as of mechanically isolated mature adipocytes, even after blocking with a specific primer the nonspecific amplification of human mitochondrial 12S rRNA. CONCLUSIONS: Our results do not support the presence of a human adipose tissue microbiota. In addition, they emphasized the technical problems encountered when applying metagenomic studies to human tissues with very low or absent bacterial load.

Disruption of astrocyte-neuron cholesterol cross talk affects neuronal function in Huntington's disease.

In the adult brain, neurons require local cholesterol production, which is supplied by astrocytes through apoE-containing lipoproteins. In Huntington's disease (HD), such cholesterol biosynthesis in the brain is severely reduced. Here we show that this defect, occurring in astrocytes, is detrimental for HD neurons. Astrocytes bearing the huntingtin protein containing increasing CAG repeats secreted less apoE-lipoprotein-bound cholesterol in the medium. Conditioned media from HD astrocytes and lipoprotein-depleted conditioned media from wild-type (wt) astrocytes were equally detrimental in a neurite outgrowth assay and did not support synaptic activity in HD neurons, compared with conditions of cholesterol supplementation or conditioned media from wt astrocytes. Molecular perturbation of cholesterol biosynthesis and efflux in astrocytes caused similarly altered astrocyte-neuron cross talk, whereas enhancement of glial SREBP2 and ABCA1 function reversed the aspects of neuronal dysfunction in HD. These findings indicate that astrocyte-mediated cholesterol homeostasis could be a potential therapeutic target to ameliorate neuronal dysfunction in HD.

Cancer stem cells and the tumor microenvironment: soloists or choral singers.

The idea of cancer stem cell (CSC) has recently moved to the forefront of cancer research. There is still a lack of a widespread consensus on their description and definition. ,The increasing literature on CSCs has compelled researchers worldwide to rewrite the natural history of cancer including those cells as principal players as well as to revise their views on tumor formation and progression. CSCs are tumor cell components that can initiate a new tumor after an apparent therapeutic eradication. A functional definition of cancer stem cell or cancer initiating cell is that of a cell which, when transplanted in a mouse model, can give rise to a tumor recapitulating the original one or even a phenotypically diverse tumor related to the tumor of origin. Since the characteristic asymmetric division of stem cells is somewhat anomalous in cancer, it might be advisable to refer to them as "stemloids". Stemness in cancer is not as much as an identity but rather a status. There is increasing evidence of the importance of the tumor and the host micro-environment in conditioning the stem cell status itself. The cancer stem cell micro-environment may be the key in the development of therapeutic strategies. We must think in terms of targeting "standard" tumor cells, cancer stem cells, and also their niche and tumor micro-environment. Here we discuss some features of cancer stem cells, and the role of the micro-environment, envisaging a choral view of cancer stem cell development and-or latency, towards development of specific therapeutic approaches. Here we propose models of replication and quiescence and the modulation by cells, genes and miRNAs. We also summarize in a table surface makers useful for the identification and isolation of CSCs.

The cerebellar network: from structure to function and dynamics.

Since the discoveries of Camillo Golgi and Ramón y Cajal, the precise cellular organization of the cerebellum has inspired major computational theories, which have then influenced the scientific thought not only on the cerebellar function but also on the brain as a whole. However, six major issues revealing a discrepancy between morphologically inspired hypothesis and function have emerged. (1) The cerebellar granular layer does not simply operate a simple combinatorial decorrelation of the inputs but performs more complex non-linear spatio-temporal transformations and is endowed with synaptic plasticity. (2) Transmission along the ascending axon and parallel fibers does not lead to beam formation but rather to vertical columns of activation. (3) The olivo-cerebellar loop could perform complex timing operations rather than error detection and teaching. (4) Purkinje cell firing dynamics are much more complex than for a linear integrator and include pacemaking, burst-pause discharges, and bistable states in response to mossy and climbing fiber synaptic inputs. (5) Long-term synaptic plasticity is far more complex than traditional parallel fiber LTD and involves also other cerebellar synapses. (6) Oscillation and resonance could set up coherent cycles of activity designing a functional geometry that goes far beyond pre-wired anatomical circuits. These observations clearly show that structure is not sufficient to explain function and that a precise knowledge on dynamics is critical to understand how the cerebellar circuit operates.

Relation between macrophage and T helper-2 lymphocyte functions in human neoplasms: neopterin, interleukin-10 and interleukin-6 blood levels in early or advanced solid tumors.

At present, it is known that there are two main mechanisms responsible for cancer-related immunosuppression, mediated by macrophages and by TH2 lymphocytes. The relation existing between macrophage- and TH2-mediated immunosuppression still remains to be understood. The present study was performed in an attempt to establish which is the correlation existing in cancer patients between IL-10 and neopterin levels, which reflect TH2- and macrophage-mediated suppressive events, respectively. The study included 40 solid tumor patients and 60 healthy subjects as controls. Serum concentrations of neopterin and IL-10 were measured by the RIA method and by an immuno-enzymetric assay, respectively. Because of its possible production both by TH2 and macrophages, serum levels of IL-6 were also determined. Neopterin, IL-10 IL-6 mean concentrations were significantly higher in cancer patients than in controls. Mean values of both neopterin and IL-6 were significantly higher in metastatic patients than in those with locally limited disease. IL-10 mean levels were also significantly higher in patients with metastatic disease. IL-6 levels were significantly correlated with those of neopterin, whereas no correlation was found between neopterin and IL-10 values. This preliminary study would suggest that macrophage- and TH2-mediated immunosuppression may occur independently in solid tumors, and that it becomes more evident with disease progression.