Expression Profiling of Autism Candidate Genes during Human Brain Development Implicates Central Immune Signaling Pathways

The Autism Spectrum Disorders (ASD) represent a clinically heterogeneous set of conditions with strong hereditary components. Despite substantial efforts to uncover the genetic basis of ASD, the genomic etiology appears complex and a clear understanding of the molecular mechanisms underlying Autism remains elusive. We hypothesized that focusing gene interaction networks on ASD-implicated genes that are highly expressed in the developing brain may reveal core mechanisms that are otherwise obscured by the genomic heterogeneity of the disorder. Here we report an in silico study of the gene expression profile from ASD-implicated genes in the unaffected developing human brain. By implementing a biologically relevant approach, we identified a subset of highly expressed ASD-candidate genes from which interactome networks were derived. Strikingly, immune signaling through NFκB, Tnf, and Jnk was central to ASD networks at multiple levels of our analysis, and cell-type specific expression suggested glia—in addition to neurons—deserve consideration. This work provides integrated genomic evidence that ASD-implicated genes may converge on central cytokine signaling pathways

Deep RNA Sequencing Reveals Novel Cardiac Transcriptomic Signatures for Physiological and Pathological Hypertrophy

Although both physiological hypertrophy (PHH) and pathological hypertrophy (PAH) of the heart have similar morphological appearances, only PAH leads to fatal heart failure. In the present study, we used RNA sequencing (RNA-Seq) to determine the transcriptomic signatures for both PHH and PAH. Approximately 13–20 million reads were obtained for both models, among which PAH showed more differentially expressed genes (DEGs) (2,041) than PHH (245). The expression of 417 genes was barely detectable in the normal heart but was suddenly activated in PAH. Among them, Foxm1 and Plk1 are of particular interest, since Ingenuity Pathway Analysis (IPA) using DEGs and upstream motif analysis showed that they are essential hub proteins that regulate the expression of downstream proteins associated with PAH. Meanwhile, 52 genes related to collagen, chemokines, and actin showed opposite expression patterns between PHH and PAH. MAZ-binding motifs were enriched in the upstream region of the participating genes. Alternative splicing (AS) of exon variants was also examined using RNA-Seq data for PAH and PHH. We found 317 and 196 exon inclusions and exon exclusions, respectively, for PAH, and 242 and 172 exon inclusions and exclusions, respectively for PHH. The AS pattern was mostly related to gains or losses of domains, changes in activity, and localization of the encoded proteins. The splicing variants of 8 genes (i.e., Fhl1, Rcan1, Ndrg2, Synpo, Ttll1, Cxxc5, Egfl7, and Tmpo) were experimentally confirmed. Multilateral pathway analysis showed that the patterns of quantitative (DEG) and qualitative (AS) changes differ depending on the type of pathway in PAH and PHH. One of the most significant changes in PHH is the severe downregulation of autoimmune pathways accompanied by significant AS. These findings revealed the unique transcriptomic signatures of PAH and PHH and also provided a more comprehensive understanding at both the quantitative and qualitative levels

Concordant Signaling Pathways Produced by Pesticide Exposure in Mice Correspond to Pathways Identified in Human Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disease in which the etiology of 90 percent of the patients is unknown. Pesticide exposure is a major risk factor for PD, and paraquat (PQ), pyridaben (PY) and maneb (MN) are amongst the most widely used pesticides. We studied mRNA expression using transcriptome sequencing (RNA-Seq) in the ventral midbrain (VMB) and striatum (STR) of PQ, PY and paraquat+maneb (MNPQ) treated mice, followed by pathway analysis. We found concordance of signaling pathways between the three pesticide models in both the VMB and STR as well as concordance in these two brain areas. The concordant signaling pathways with relevance to PD pathogenesis were e.g. axonal guidance signaling, Wnt/β-catenin signaling, as well as pathways not previously linked to PD, e.g. basal cell carcinoma, human embryonic stem cell pluripotency and role of macrophages, fibroblasts and endothelial cells in rheumatoid arthritis. Human PD pathways previously identified by expression analysis, concordant with VMB pathways identified in our study were axonal guidance signaling, Wnt/β-catenin signaling, IL-6 signaling, ephrin receptor signaling, TGF-β signaling, PPAR signaling and G-protein coupled receptor signaling. Human PD pathways concordant with the STR pathways in our study were Wnt/β-catenin signaling, axonal guidance signaling and G-protein coupled receptor signaling. Peroxisome proliferator activated receptor delta (Ppard) and G-Protein Coupled Receptors (GPCRs) were common genes in VMB and STR identified by network analysis. In conclusion, the pesticides PQ, PY and MNPQ elicit common signaling pathways in the VMB and STR in mice, which are concordant with known signaling pathways identified in human PD, suggesting that these pathways contribute to the pathogenesis of idiopathic PD. The analysis of these networks and pathways may therefore lead to improved understanding of disease pathogenesis, and potential novel therapeutic targets

An Integrated Strategy to Study Muscle Development and Myofilament Structure in Caenorhabditis elegans

A crucial step in the development of muscle cells in all metazoan animals is the assembly and anchorage of the sarcomere, the essential repeat unit responsible for muscle contraction. In Caenorhabditis elegans, many of the critical proteins involved in this process have been uncovered through mutational screens focusing on uncoordinated movement and embryonic arrest phenotypes. We propose that additional sarcomeric proteins exist for which there is a less severe, or entirely different, mutant phenotype produced in their absence. We have used Serial Analysis of Gene Expression (SAGE) to generate a comprehensive profile of late embryonic muscle gene expression. We generated two replicate long SAGE libraries for sorted embryonic muscle cells, identifying 7,974 protein-coding genes. A refined list of 3,577 genes expressed in muscle cells was compiled from the overlap between our SAGE data and available microarray data. Using the genes in our refined list, we have performed two separate RNA interference (RNAi) screens to identify novel genes that play a role in sarcomere assembly and/or maintenance in either embryonic or adult muscle. To identify muscle defects in embryos, we screened specifically for the Pat embryonic arrest phenotype. To visualize muscle defects in adult animals, we fed dsRNA to worms producing a GFP-tagged myosin protein, thus allowing us to analyze their myofilament organization under gene knockdown conditions using fluorescence microscopy. By eliminating or severely reducing the expression of 3,300 genes using RNAi, we identified 122 genes necessary for proper myofilament organization, 108 of which are genes without a previously characterized role in muscle. Many of the genes affecting sarcomere integrity have human homologs for which little or nothing is known

ICAR: endoscopic skull‐base surgery

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