Biology subjects

Jia, Y.

Publications and source records attributed to Jia, Y..

10 recordsLinked to original sources

bioRxiv2018

Divergent neuronal DNA methylation patterns across human cortical development: Critical periods and a unique role of CpH methylation

We have characterized the landscape of DNA methylation (DNAm) across the first two decades of human neocortical development in NeuN+ neurons using whole-genome bisulfite sequencing and compared them to non-neurons (primarily glia) and prenatal homogenate cortex. We show that DNAm changes more dramatically during the first five years of postnatal life than during the entire remaining period. We further refined global patterns of increasingly divergent neuronal CpG and CpH methylation (mCpG and mCpH) into six developmental trajectories and found that in contrast to genome-wide patterns, neighboring mCpG and mCpH levels within these regions were highly correlated. We then integrated paired RNA-seq data and identified direct regulation of hundreds of transcripts and their splicing events exclusively by mCpH levels, independently from mCpG levels, across this period. We finally explored the relationship between DNAm patterns and development of brain-related phenotypes and found enriched heritability for many phenotypes within DNAm features we identify.

neuroscience↗

bioRxiv2018

Gut Microbiota in male patients with chronic traumatic complete spinal cord injury

This study examined the diversity and structure of gut microbiota in healthy adults and chronic traumatic complete spinal cord injury (SCI) patients, documented neurogenic bowel management of SCI patients. The V3-V4 region of 16S rRNA gene from DNA of 91 fecal samples of 48 healthy and 43 diseased subjects was amplified and sequenced. There was difference in gut microbiota between healthy adult males and females. Neurogenic bowel dysfunction (NBD) was common in patients with chronic traumatic complete SCI, patients with quadriplegia have longer time to defecate than paraplegic patients, with higher NBD scores and heavier neurogenic bowel symptoms. Gut microbiota dysbiosis existed in SCI patients. The abundance of Veillonellaceae and Prevotellaceae increased while Bacteroidaceae and Bacteroides decreased in SCI group. The abundance of Bacteroidaceae, Bacteroides in quadriplegia group and Acidaminococcaceae, Blautia in paraplegia group were significant high than the health male group. Serum biomarkers GLU, HDL, CR and NBD symptoms defecation time, COURSE had significant correlation with microbial community structure. This study presents a comprehensive landscape of gut microbiota in adult male patients with chronic traumatic complete SCI and documents their neurogenic bowel management. The gut microbiota dysbiosis of SCI patients was correlation with serum biomarkers and NBD symptoms.\n\nIMPORTANCENeurogenic bowel dysfunction is a major physical and psychological problem in patients with spinal cord injury, which can seriously affect the quality life of them. Gut dysbiosis are highly likely to occur in spinal cord injury patients There are few studies on intestinal microecology after spinal cord injury, and the clinical studies are fewer. It is importance to document their neurogenic bowel management and present a landscape of gut microbiota in them. We found the gut microbiota dysbiosis of spinal cord injury patients was correlation with serum biomarkers and neurogenic bowel dysfunction symptoms. These results may have implications in the next study about metagenomics and precision treatment of neurogenic bowel dysfunction in spinal cord injury patients.

neuroscience↗

bioRxiv2018

Transcriptome analysis of Culter alburnus gonad tissues for discovery of sex-related genes

Culter alburnus is an important commercially fish species for freshwater breeding in China, and the females grow faster than the males. However, the molecular genetic mechanism of sex determination in C.alburnus is still poorly characterized. Here, we performed de novo assembly of a transcriptome from adult fish tissues of different gender using short read sequencing technology (Illumina). Our results showed that a total of 364,650 unigenes using Trinity software were obtained, giving rise to an average of 561.92 bp per read. Among them, 70,215 sequences matched known genes, including 5,892 male-biased unigenes and 942 female-biased unigenes. Many sex-related genes and pathways were identified based on annotation information. These results would provide new insights into the genetic mechanism of C.alburnus sex determination and also establish an important foundation for further research on aquaculture breeding.

bioinformatics↗

bioRxiv2018

Cryo-EM structure of the volume-regulated anion channel LRRC8

Maintenance of cell volume against osmotic change is crucial for proper cell functions, such as cell proliferation and migration. The leucine-rich repeat-containing 8 (LRRC8) proteins are anion selective channels, and were recently identified as pore components of the volume-regulated anion channels (VRACs), which extrude anions to decrease the cell volume upon cell-swelling. Here, we present the human LRRC8A structure, determined by a single-particle cryo-electron microscopy analysis. The sea anemone-like structure represents a trimer of dimers assembly, rather than a symmetrical hexameric assembly. The four-spanning transmembrane region has a gap junction channel-like membrane topology, while the LRR region containing 15 leucine-rich repeats forms a long twisted arc. The channel pore is along the central axis and constricted on the extracellular side, where the highly conserved polar and charged residues at the tip of the extracellular helix contribute to the anion and other osmolyte permeability. Comparing the two structural populations facilitated the identification of both compact and relaxed conformations, suggesting that the LRR region is flexible and mobile with rigid-body motions, which might be implicated in structural transitions upon pore opening. Overall, our structure provides a framework for understanding the molecular mechanisms of this unique class of ion channels.

molecular biology↗

bioRxiv2018

The lysine demethylase dKDM2 is non-essential for viability, but regulates circadian rhythms in Drosophila

Post-translational modification of histones, such as histone methylation controlled by specific methyltransferases and demethylases, play critical roles in modulating chromatin dynamics and transcription in eukaryotes. Misregulation of histone methylation can lead to aberrant gene expression, thereby contributing to abnormal development and diseases such as cancer. As such, the mammalian lysine-specific demethylase 2 (KDM2) homologs, KDM2A and KDM2B, are either oncogenic or tumor suppressive, depending on specific pathological contexts. However, the role of KDM2 proteins during development in the whole organisms remains poorly understood. Unlike vertebrates, Drosophila has only one KDM2 homolog (dKDM2), but its functions in vivo remain elusive due to the complexities of the existing mutant alleles. To address this problem, we have generated two dKdm2 null alleles using the CRISPR/Cas9 technique. These dKdm2 homozygous mutants are fully viable and fertile, with no developmental defects observed under laboratory conditions. However, the dKdm2 null mutant adults display defects in circadian rhythms. Most of the dKdm2 mutants become arrhythmic under constant darkness, while the circadian period of the rhythmic mutant flies is approximately one hour shorter than the control. Interestingly, opposite defects are observed when dKDM2 is overexpressed in circadian pacemaker neurons. Taken together, these results demonstrate that dKdm2 is not essential for viability; instead, dKDM2 protein plays important roles in regulating circadian rhythms in Drosophila. Further analyses of the molecular mechanisms of how dKDM2 and its orthologs in vertebrates regulate circadian rhythms will advance our understanding of the epigenetic regulations of circadian clocks.

developmental biology↗

bioRxiv2018

Cullin1 represses systematic inflammasome activation by binding and catalyzing NLRP3 ubiquitination

Activation of the NLRP3 inflammasome is a key process of host immune response, the first line of defense against cellular stresses and pathogen infections. However, excessive inflammasome activation damages the hosts, and thus it must be precisely controlled. The mechanism underlying the repression of systematic inflammasome activation remains largely unknown. This study reveals that CUL1, a key component of the SCF E3 ligase, plays a critical role in regulation of the inflammasome. CUL1 suppresses the inflammasome activation in HEK293T cells, inhibits endogenous NLRP3 in macrophages, and represses inflammatory responses in C57BL/6 mice. Under normal physiological conditions, CUL1 interacts with NLRP3 to disrupt the inflammasome assembly, and catalyzes NLRP3 ubiquitination to repress the inflammasome activation. In response to inflammatory stimuli, CUL1 disassociates from NLRP3 to release the repression of NLRP3 inflammasome activation. This work reveals a distinct mechanism underlying the repression of inflammasome activation under physiological conditions and the induction of inflammasome activation in response to inflammatory stimuli, and thus provides insights into the prevention and treatment of infectious and inflammatory diseases.

immunology↗

bioRxiv2018

Arsenite exposure inhibits histone acetyltransferase p300 for attenuating H3K27ac at enhancers in low-dose exposed mouse embryonic fibroblast cells

Epidemiological investigations have validated the positive relationships between arsenic in drinking water and several cancers, including skin, liver and lung cancers. Besides genotoxicity, arsenic exposure-related pathogenesis of disease is widely considered through epigenetic mechanisms; however, the underlying mechanistic insight remains elusive. Herein we explore the initial epigenetic changes via acute low-dose arsenite exposures of mouse embryonic fibroblast (MEF) cells and Dot1L knockout MEF (Dot1L-/- for abbreviation) cells. Our RNA-seq and Western blot data demonstrated that, in both cell lines, acute low-dose arsenite exposure abolished histone acetyltransferase p300 at the RNA level and subsequent protein level. Consequently, p300-specific main target histone H3K27ac, a marker separating active from poised enhancers, decreased dramatically as validated by both Western blot and ChIP-seq analyses. Concomitantly, H3K4me1 as another well-known marker for enhancers also showed significant decreases, suggesting an underappreciated crosstalk between H3K4me1 and H3K27ac involved in arsenite exposure. Significantly, arsenite exposure-reduced H3K27ac and H3K4me1 inhibit the expression of genes including EP300 itself and Kruppel Like Factor 4(Klf4), a tumor suppressor gene. Collectively, our investigations identify p300 as an internal bridging factor within cells to sense external environmental arsenite exposure to alter chromatin, thereby changing gene transcription for disease pathogenesis.

pharmacology and toxicology↗

bioRxiv2018

Next generation CRISPR/Cas9 transcriptional activation in Drosophila using flySAM

CRISPR/Cas9-based transcriptional activation (CRISPRa) has recently emerged as a powerful and scalable technique for systematic over-expression genetic analysis in Drosophila melanogaster. We present flySAM, a potent new tool for in vivo CRISPRa, which offers a major improvement over existing strategies in terms of effectiveness, scalability, and ease-of-use. flySAM outperforms existing in vivo CRISPRa strategies, and approximates phenotypes obtained using traditional Gal4-UAS over-expression. Further, because flySAM typically only requires a single sgRNA, it dramatically improves scalability. We use flySAM to demonstrate multiplexed CRISPRa, which has not been previously shown in vivo. In addition, we have simplified the experimental usage of flySAM by creating a single vector encoding both the UAS:Cas9-activator and the sgRNA, allowing for inducible CRISPRa in a single genetic cross. flySAM will thus replace previous CRISPRa strategies as the basis of our growing genome-wide transgenic over-expression resource, TRiP-OE.

genetics↗

bioRxiv2018

UBE3A-mediated p18/LAMTOR1 ubiquitination and degradation regulate mTORC1 activity and synaptic plasticity

Accumulating evidence indicates that the lysosomal Ragulator complex is essential for full activation of the mechanistic target of rapamycin complex 1 (mTORC1). Abnormal mTORC1 activation has been implicated in several developmental neurological disorders, including Angelman syndrome (AS), which is caused by maternal deficiency of the ubiquitin E3 ligase UBE3A. Here we report that Ube3a regulates mTORC1 signaling by targeting p18, a subunit of the Ragulator. Ube3a ubiquinates p18, resulting in its proteasomal degradation, and Ube3a deficiency in hippocampus of AS mice results in increased lysosomal localization of p18 and other members of the Ragulator-Rag complex, such as RagA, and increased mTORC1 activity. P18 down-regulation by siRNA or shRNA in hippocampal CA1 neurons of AS mice reduces elevated mTORC1 activity and improves long-term potentiation (LTP) and dendritic spine maturation. Our results indicate that Ube3a-mediated regulation of p18 and subsequent mTORC1 signaling is critical for typical synaptic plasticity and dendritic spine development.

neuroscience↗

bioRxiv2017

Genetic Single Neuron Anatomy reveals fine granularity of cortical interneuron subtypes

Parsing diverse nerve cells into biological types is necessary for understanding neural circuit organization. Morphology is an intuitive criterion for neuronal classification and a proxy of connectivity, but morphological diversity and variability often preclude resolving the granularity of discrete cell groups from population continuum. Combining genetic labeling with high-resolution, large volume light microscopy, we established a platform of genetic single neuron anatomy that resolves, registers and quantifies complete neuron morphologies in the mouse brain. We discovered that cortical axo-axonic cells (AACs), a cardinal GABAergic interneuron type that controls pyramidal neuron (PyN) spiking at axon initial segment, consist of multiple subtypes distinguished by laminar position, dendritic and axonal arborization patterns. Whereas the laminar arrangements of AAC dendrites reflect differential recruitment by input streams, the laminar distribution and local geometry of AAC axons enable differential innervation of PyN ensembles. Therefore, interneuron types likely consist of fine-grained subtypes with distinct input-output connectivity patterns.

neuroscience↗