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result(s) for
"Liu, Yuejia"
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Vagal sensory neurons mediate the Bezold–Jarisch reflex and induce syncope
2023
Visceral sensory pathways mediate homeostatic reflexes, the dysfunction of which leads to many neurological disorders
1
. The Bezold–Jarisch reflex (BJR), first described
2
,
3
in 1867, is a cardioinhibitory reflex that is speculated to be mediated by vagal sensory neurons (VSNs) that also triggers syncope. However, the molecular identity, anatomical organization, physiological characteristics and behavioural influence of cardiac VSNs remain mostly unknown. Here we leveraged single-cell RNA-sequencing data and HYBRiD tissue clearing
4
to show that VSNs that express neuropeptide Y receptor Y2 (NPY2R) predominately connect the heart ventricular wall to the area postrema. Optogenetic activation of NPY2R VSNs elicits the classic triad of BJR responses—hypotension, bradycardia and suppressed respiration—and causes an animal to faint. Photostimulation during high-resolution echocardiography and laser Doppler flowmetry with behavioural observation revealed a range of phenotypes reflected in clinical syncope, including reduced cardiac output, cerebral hypoperfusion, pupil dilation and eye-roll. Large-scale Neuropixels brain recordings and machine-learning-based modelling showed that this manipulation causes the suppression of activity across a large distributed neuronal population that is not explained by changes in spontaneous behavioural movements. Additionally, bidirectional manipulation of the periventricular zone had a push–pull effect, with inhibition leading to longer syncope periods and activation inducing arousal. Finally, ablating NPY2R VSNs specifically abolished the BJR. Combined, these results demonstrate a genetically defined cardiac reflex that recapitulates characteristics of human syncope at physiological, behavioural and neural network levels.
The molecular mechanisms underlying the Bezold–Jarisch reflex and syncope (fainting) involve vagal sensory neurons that express neuropeptide Y receptor Y2, the deletion of which in animal models abolishes the Bezold–Jarisch reflex.
Journal Article
SEPepQuant enhances the detection of possible isoform regulations in shotgun proteomics
2023
Shotgun proteomics is essential for protein identification and quantification in biomedical research, but protein isoform characterization is challenging due to the extensive number of peptides shared across proteins, hindering our understanding of protein isoform regulation and their roles in normal and disease biology. We systematically assess the challenge and opportunities of shotgun proteomics-based protein isoform characterization using in silico and experimental data, and then present SEPepQuant, a graph theory-based approach to maximize isoform characterization. Using published data from one induced pluripotent stem cell study and two human hepatocellular carcinoma studies, we demonstrate the ability of SEPepQuant in addressing the key limitations of existing methods, providing more comprehensive isoform-level characterization, identifying hundreds of isoform-level regulation events, and facilitating streamlined cross-study comparisons. Our analysis provides solid evidence to support a widespread role of protein isoform regulation in normal and disease processes, and SEPepQuant has broad applications to biological and translational research.
Protein isoform quantification in shotgun proteomics is challenging due to the mapping of many peptides to multiple protein isoforms. Here, the authors present a computational method SEPepQuant and demonstrate its utility in revealing protein isoform level regulation in shotgun proteomics.
Journal Article
Quantitative proteomics reveals the protective effects of Yinchenzhufu decoction against cholestatic liver fibrosis in mice by inhibiting the PDGFRβ/PI3K/AKT pathway
2024
Introduction: Yinchenzhufu decoction (YCZFD) is a traditional Chinese medicine formula with hepatoprotective effects. In this study, the protective effects of YCZFD against cholestatic liver fibrosis (CLF) and its underlying mechanisms were evaluated. Methods: A 3, 5-diethoxycarbonyl-1, 4-dihydro-collidine (DDC)-induced cholestatic mouse model was used to investigate the amelioration of YCZFD on CLF. Data-independent acquisition-based mass spectrometry was performed to investigate proteomic changes in the livers of mice in three groups: control, model, and model treated with high-dose YCZFD. The effects of YCZFD on the expression of key proteins were confirmed in mice and cell models. Results: YCZFD significantly decreased the levels of serum biochemical, liver injury, and fibrosis indicators of cholestatic mice. The proteomics indicated that 460 differentially expressed proteins (DEPs) were identified among control, model, and model treated with high-dose YCZFD groups. Enrichment analyses of these DEPs revealed that YCZFD influenced multiple pathways, including PI3K-Akt, focal adhesion, ECM–receptor interaction, glutathione metabolism, and steroid biosynthesis pathways. The expression of platelet derived growth factor receptor beta (PDGFRβ), a receptor associated with the PI3K/AKT and focal adhesion pathways, was upregulated in the livers of cholestatic mice but downregulated by YCZFD. The effects of YCZFD on the expression of key proteins in the PDGFRβ/PI3K/AKT pathway were further confirmed in mice and transforming growth factor-β-induced hepatic stellate cells. We uncovered seven plant metabolites (chlorogenic acid, scoparone, isoliquiritigenin, glycyrrhetinic acid, formononetin, atractylenolide I, and benzoylaconitine) of YCZFD that may regulate PDGFRβ expression. Conclusion: YCZFD substantially protects against DDC-induced CLF mainly through regulating the PDGFRβ/PI3K/AKT signaling pathway.
Journal Article
An enhanced low overhead and stable clustering scheme for crossroads in VANETs
by
Liu, Yuejia
,
Jing, Tao
,
Huo, Yan
in
Ad hoc networks
,
Big Data Analytics for Cyber-Physical Systems
,
Clustering
2016
In this paper, we study the clustering problem for crossroads in Vehicular Ad hoc Networks (VANETs). Considering the load balancing of both the whole network and each cluster based on the multiple metrics, an Enhanced Low Overhead and Stable Clustering (EnLOSC) scheme is presented to ensure the stability and security of clusters and to reduce the communication overhead in this case. The proposed capability metric, designed to find the vehicles with similar direction and better channel quality, is exploited in the processes of formation and maintenance to determine which node is suitable for a cluster head. Based on this, a Cluster Head Electing in Advance Mechanism (CHEAM) is developed in order to fairly select a new head for “isolated” vehicles that may not belong to a cluster. Meanwhile, other metrics are related to the node density and cluster size, which are exploited in the Cluster Merging and Splitting Mechanisms to keep the system load balancing and to improve the communication quality. Furthermore, the proposed Discovery and Elimination Scheme (DES) is designed to tackle the malicious nodes that may hurt the cluster communication. Accordingly, an enhanced cluster maintenance strategy with multi-metrics and a secure scheme is proposed so as to reduce the number of isolated vehicles, keep appropriate loading for each cluster head, and protect the whole link over cluster communication. Numerical results and discussion indicate that the cluster stability, communication overhead, load balance, and security can be significantly enhanced by our proposed scheme.
Journal Article
FBXW7 overexpression suppresses renal cancer cell proliferation and induces apoptosis
by
Liu, Yuejia
,
Lin, Youcheng
,
Fu, Yu
in
Apoptosis - genetics
,
Biomarkers, Tumor - genetics
,
Carcinoma, Renal Cell - genetics
2015
FBXW7 gene (F-box and WD-40 domain protein 7) is also named HCDC4 and is a significant tumor suppressor gene, which can regulate human cell cycle, proliferation and differentiation. In this study, we tend to investigate protein expression and related biological functions of FBXW7 gene. FBXW7 expression level in renal cell carcinoma (RCC) tissues is highly related to its clinical pathologic grade (
P
= 0.0094) and TNM phase (
P
= 0.0080) and is highly lower than in paracancerous normal tissues through immunohistochemistry study. FBXW7 high-expression patients have overall better prognosis than low-expression patients (
P
< 0.001). After transfected with FBXW7 plasmid, the RCC cell lines ACHN and A704 showed a depressed proliferation activity and high proportion of apoptosis through CCK8, colony formation and flow cytometry assay studies. By Western blot analysis, expression of cell proliferation-activating protein c-Myc and c-Jun is downregulated in FBXW7 high-expression RCC compared with negative control. These data suggested that FBXW7 is a significant tumor suppressor gene in RCC.
Journal Article
Pubertal sex hormones control transcriptional trajectories in the medial preoptic area
2021
Pubertal maturation aids development of emotion, cognition, and reproduction. We investigated transcriptional dynamics in the medial preoptic area (MPOA), a hypothalamic center for reproductive behaviors, in male and female mice at single-cell resolution (scRNAseq) during puberty. Defined subsets of neurons expressing Slc32a1 and Esr1 (Vgat+ Esr1+) were the most transcriptionally dynamic compared to other cell types throughout puberty. These cell type specific transcriptional progressions towards adulthood were bidirectionally controlled by the levels of circulating testosterone and estradiol. Selective deletion of Esr1 in Slc32a1-expressing cells in the MPOA prior to puberty arrested transcriptional progression and revealed a sexually dimorphic gene-regulatory network governed by Esr1. Deletion of Esr1 in Vgat+ cells prevented the development of mating behavior in both sexes. These analyses reveal both sexually common and dimorphic transcriptional progressions during puberty as well as their regulatory mechanisms, which have important implications towards understanding adaptative and maladaptive processes governing adolescent brain development. Competing Interest Statement The authors have declared no competing interest.
High-Temperature Antioxidant Screening for Silicone Oil
by
Wang, Hui Zhen
,
Zhang, Jun Qing
,
Zhong, Li
in
Antioxidants
,
Computational fluid dynamics
,
Deterioration
2014
In order to prevent silicone oils from suffering oxidative deterioration and prolong its service life at high-temperature, an effective way is adding an appropriate antioxidant package in the base oil. Antioxidants can not only inhibit oil oxidation that produces acidic substances but also prevent the viscosity of oil from increasing. In this work, 1,3-dioctyl-1,1,3,3-tetraphenyl-disiloxane (OPDS) was used as silicone base oil, and several commercially available antioxidants were screened. Data show that TNPP, phenyl sulfide, 2088, and KY01 were effective at 300 oC, which could be further used as candidates for the antioxidant formulations of silicone base oils used as high temperature lubricants or hydraulic oils.
Journal Article
Possible linkage between winter extreme low temperature events over China and synoptic-scale transient wave activity
Based on NECP/NCAR reanalysis data and daily temperature data of 743 stations in China, possible causes of winter extreme low temperature events are explored from the perspective of the synoptic-scale transient wave (STW) activity. Results suggest that there is a close linkage between STW activity and extreme low temperature events. Firstly, case studies are carried out on the years with the most and least frequent extreme low temperature events. In the winter of 1967, two strong and stable STW trains were maintained over the Eurasian continent, and the strong westerly jet provided a good channel for the propagation of STW. Located in the downstream area of those two STW trains, China was significantly influenced by them and experienced frequent extreme low temperature events. Further analysis suggest that the intensity of the upstream transient wave and the areas where the transient waves reached are completely consistent with the intensity of extreme low temperature and the areas where frequent extreme low temperature event happened, respectively. In contrast, Westerly jet in 2006 was weaker and the path of transient wave propagation was shorter and weaker, resulting in the low frequency of extreme temperature. Secondly, in their long term variations, westerly jet is also consistent with the extreme low temperature frequency. The transient wave path changed before and after the 1980s. Further investigation suggests that transient wave intensities in key areas exhibit in-phase changes with the frequency of extreme low temperature events in the periods of 1959-1979 and 1986-2006. Mean- while, the main features of transient wave activities in high-frequent years and low-frequent years of extreme low temperature events are similar to those of 1967 and 2006, respectively. Results indicate that winter extreme low temperature events in China have a very close relationship with the transient wave activity, implying the propagation and activity of STW are important factors affecting the winter extreme low temperature events in China. This study can also provide a new clue for better under- standing the mechanisms of the extreme temperature events.
Journal Article
Transcriptional and Spatial Resolution of Cell Types in the Mammalian Habenula
by
Liu, Yuejia
,
Basiri, Marcus L
,
Johnston, Nathan L
in
Habenula
,
Hybridization
,
Luteinizing hormone
2019
The habenula complex is appreciated as a critical regulator of motivated and pathological behavioral states via its output to midbrain nuclei. Despite this, transcriptional definition of cell populations that comprise both the medial (MHb) and lateral habenular (LHb) subregions in mammals remain undefined. To resolve this, we performed single-cell transcriptional profiling and highly multiplexed in situ hybridization experiments of the mouse habenula complex in naive mice and those exposed to an acute aversive stimulus. Transcriptionally distinct neuronal cell types identified within the MHb and LHb, were spatially defined, and differentially engaged by aversive stimuli. Cell types identified in mice, also displayed a high degree of transcriptional similarity to those previously described in zebrafish, highlighting the well conserved nature of habenular cell types across the phylum. These data identify key molecular targets within habenula cell types, and provide a critical resource for future studies.
Massively parallel in vivo Perturb-seq reveals cell type-specific transcriptional networks in cortical development
2023
Systematic analysis of gene function across diverse cell types in vivo is hindered by two challenges: obtaining sufficient cells from live tissues and accurately identifying each cell's perturbation in high-throughput single-cell assays. Leveraging AAV's versatile cell type tropism and high labeling capacity, we expanded the resolution and scale of in vivo CRISPR screens: allowing phenotypic analysis at single-cell resolution across a multitude of cell types in the embryonic brain, adult brain, and peripheral nervous system. We undertook extensive tests of 86 AAV serotypes, combined with a transposon system, to substantially amplify labeling and accelerate in vivo gene delivery from weeks to days. Using this platform, we performed an in utero genetic screen as proof-of-principle and identified pleiotropic regulatory networks of Foxg1 in cortical development, including Layer 6 corticothalamic neurons where it tightly controls distinct networks essential for cell fate specification. Notably, our platform can label >6% of cerebral cells, surpassing the current state-of-the-art efficacy at <0.1% (mediated by lentivirus), and achieve analysis of over 30,000 cells in one experiment, thus enabling massively parallel in vivo Perturb-seq. Compatible with various perturbation techniques (CRISPRa/i) and phenotypic measurements (single-cell or spatial multi-omics), our platform presents a flexible, modular approach to interrogate gene function across diverse cell types in vivo, connecting gene variants to their causal functions.Systematic analysis of gene function across diverse cell types in vivo is hindered by two challenges: obtaining sufficient cells from live tissues and accurately identifying each cell's perturbation in high-throughput single-cell assays. Leveraging AAV's versatile cell type tropism and high labeling capacity, we expanded the resolution and scale of in vivo CRISPR screens: allowing phenotypic analysis at single-cell resolution across a multitude of cell types in the embryonic brain, adult brain, and peripheral nervous system. We undertook extensive tests of 86 AAV serotypes, combined with a transposon system, to substantially amplify labeling and accelerate in vivo gene delivery from weeks to days. Using this platform, we performed an in utero genetic screen as proof-of-principle and identified pleiotropic regulatory networks of Foxg1 in cortical development, including Layer 6 corticothalamic neurons where it tightly controls distinct networks essential for cell fate specification. Notably, our platform can label >6% of cerebral cells, surpassing the current state-of-the-art efficacy at <0.1% (mediated by lentivirus), and achieve analysis of over 30,000 cells in one experiment, thus enabling massively parallel in vivo Perturb-seq. Compatible with various perturbation techniques (CRISPRa/i) and phenotypic measurements (single-cell or spatial multi-omics), our platform presents a flexible, modular approach to interrogate gene function across diverse cell types in vivo, connecting gene variants to their causal functions.
Journal Article