Biology subjects

Zhan, X.

Publications and source records attributed to Zhan, X..

At least 73 records · Page 4Linked to original sources

bioRxiv2021

Structural mapping of antibody landscapes to human betacoronavirus spike proteins

Preexisting immunity against seasonal coronaviruses (CoV) represents an important variable in predicting antibody responses and disease severity to Severe Acute Respiratory Syndrome CoV-2 (SARS-2) infections. We used electron microscopy based polyclonal epitope mapping (EMPEM) to characterize the antibody specificities against {beta}-CoV spike proteins in sera from healthy donors (HDs) or SARS-2 convalescent donors (CDs). We observed that most HDs possessed antibodies specific to seasonal human CoVs (HCoVs) OC43 and HKU1 spike proteins while the CDs showed reactivity across all human {beta}-CoVs. Detailed molecular mapping of spike-antibody complexes revealed epitopes that were differentially targeted by antibodies in preexisting and convalescent serum. Our studies provide an antigenic landscape to {beta}-HCoV spikes in the general population serving as a basis for cross-reactive epitope analyses in SARS-2 -infected individuals. One-Sentence summaryWe present the epitope mapping of polyclonal antibodies against beta-coronavirus spike proteins in human sera.

immunology↗

bioRxiv2021

KIRCLE: An Analysis of Variations in KIR Genes in The Cancer Genome Atlas and UK Biobank

BackgroundNatural killer (NK) cells represent a critical component of the innate immune systems response against cancer and viral infections, among other diseases. To distinguish healthy host cells from infected or tumor cells, killer immunoglobulin receptors (KIR) on NK cells bind and recognize Human Leukocyte Antigen (HLA) complexes on their target cells. Just like the HLAs they bind, these KIRs exhibit high allelic diversity in the human population. ResultsIn order to better understand these immunoreceptors, we have developed KIRCLE, a novel method for genotyping individual KIR genes from whole exome sequencing data, and used it to analyze approximately 60,000 patient samples in The Cancer Genome Atlas and UK Biobank. We were able to assess population frequencies for different KIR alleles and demonstrate that, similar to HLA alleles, individuals KIR alleles correlate strongly with their ethnicities. In addition, we observed associations between different KIR alleles and HLA alleles, including HLA-B*53 with KIR3DL2*013 (Fishers Exact FDR = 7.64e-51). Finally, we showcased statistically significant associations between KIR alleles and various clinical correlates, including peptic ulcer disease (Fishers Exact FDR = 0.0429) and age of onset of atopy and various KIR alleles (Mann-Whitney-U FDR = 0.0751). ConclusionsKIR polymorphism and NK cells play a critical role in many diseases, often through their interactions with HLA complexes. Peptic ulcer disease and atopy are just two diseases in which NK cells may play a role beyond their "classical" realm of anti-tumor and anti-viral responses.

bioinformatics↗

bioRxiv2021

Edaravone activates the GDNF/RET neurotrophic signaling pathway and protects mRNA-induced motor neurons from iPS cells.

BackgroundSpinal cord motor neurons (MNs) from human iPS cells (iPSCs) have wide applications in disease modeling and therapeutic development for amyotrophic lateral sclerosis (ALS) and other MN-associated neurodegenerative diseases. We need highly efficient MN differentiation strategies for generating iPSC-derived disease models that closely recapitulate the genetic and phenotypic complexity of ALS. An important application of these models is to understand molecular mechanisms of action of FDA-approved ALS drugs that only show modest clinical efficacy. Novel mechanistic insights will help us design optimal therapeutic strategies together with predictive biomarkers to achieve better efficacy. MethodsWe induce efficient MN differentiation from iPSCs in 4 days using synthetic mRNAs coding two transcription factors (Ngn2 and Olig2) with phosphosite modification. These MNs after extensive characterization were applied in electrophysiological and neurotoxicity assays as well as transcriptomic analysis, to study the neuroprotective effect and molecular mechanisms of edaravone, an FDA-approved drug for ALS, for improving its clinical efficacy. ResultsWe generate highly pure and functional mRNA-induced MNs (miMNs) from normal and ALS iPSCs, as well as embryonic stem cells. Edaravone alleviates H2O2-induced neurotoxicity and electrophysiological dysfunction in miMNs, demonstrating its neuroprotective effect that was also found in the glutamate-induced miMN neurotoxicity model. Guided by the transcriptomic analysis, we show a previously unrecognized effect of edaravone to induce the GDNF receptor RET and the GDNF/RET neurotrophic signaling in vitro and in vivo, suggesting a clinically translatable strategy to activate this key neuroprotective signaling. Notably, edaravone can replace required neurotrophic factors (BDNF and GDNF) to support long-term miMN survival and maturation, further supporting the neurotrophic function of edaravone-activated signaling. Furthermore, we show that edaravone and GDNF combined treatment more effectively protects miMNs from H2O2-induced neurotoxicity than single treatment, suggesting a potential combination strategy for ALS treatment. ConclusionsThis study provides methodology to facilitate iPSC differentiation and disease modeling. Our discoveries will facilitate the development of optimal edaravone-based therapies for ALS and potentially other neurodegenerative diseases. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=145 SRC="FIGDIR/small/443325v2_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@cd0bc9org.highwire.dtl.DTLVardef@1c0c0b6org.highwire.dtl.DTLVardef@1ac0952org.highwire.dtl.DTLVardef@1980f5b_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2021

Role of PARP1 in oligodendrocyte differentiation during developmental myelination and remyelination after myelin damage

The function of poly(ADP-ribosyl) polymerase 1 (PARP1) in myelination and remyelination of the central nervous system (CNS) remain enigmatic. Here we report that PARP1 is an intrinsic driver for oligodendroglial development and myelination. Genetic PARP1 depletion impairs the differentiation of oligodendrocyte progenitor cells (OPCs) into oligodendrocytes and impedes CNS myelination. Mechanistically, PARP1-mediated PARylation activity is not only necessary but also sufficient for OPC differentiation. At the molecular level, we identify the RNA-binding protein Myef2 as a novel PARylated target which we show controls OPC differentiation through PARylation-modulated de-repression of myelin protein expression. Furthermore, PARP1s enzymatic activity is necessary for oligodendrocyte and myelin regeneration after demyelination. Together, our findings suggest that PARP1-mediated PARylation activity may be a potential therapeutic target for promoting OPC differentiation and remyelination in neurological disorders characterized by arrested OPC differentiation and remyelination failure such as multiple sclerosis.

neuroscience↗

bioRxiv2021

Towards a comprehensive delineation of white matter tract-related deformation

Finite element (FE) models of the human head are valuable instruments to explore the mechanobiological pathway from external loading, localized brain response, and resultant injury risks. The injury predictability of these models depends on the use of effective criteria as injury predictors. The FE-derived normal deformation along white matter (WM) fiber tracts (i.e., tract-oriented strain) has recently been suggested as an appropriate predictor for axonal injury. However, the tract-oriented strain only represents a partial depiction of the WM fiber tract deformation. A comprehensive delineation of tract-related deformation may improve the injury predictability of the FE head model by delivering new tract-related criteria as injury predictors. Thus, the present study performed a theoretical strain analysis to comprehensively characterize the WM fiber tract deformation by relating the strain tensor of the WM element to its embedded fiber tract. Three new tract-related strains with exact analytical solutions were proposed, measuring the normal deformation perpendicular to the fiber tracts (i.e., tract-perpendicular strain), and shear deformation along and perpendicular to the fiber tracts (i.e., axial-shear strain and lateral-shear strain, respectively). The injury predictability of these three newly-proposed strain peaks along with the previously-used tract-oriented strain peak and maximum principal strain (MPS) were evaluated by simulating 151 impacts with known outcome (concussion or non-concussion). The results preliminarily showed that four tract-related strain peaks exhibited superior performance than MPS in discriminating concussion and non-concussion cases. This study presents a comprehensive quantification of WM tract-related deformation and advocates the use of orientation-dependent strains as criteria for injury prediction, which may ultimately contribute to an advanced mechanobiological understanding and enhanced computational predictability of brain injury.

bioengineering↗

bioRxiv2020

HiddenVis: a Hidden State Visualization Toolkit to Visualize and Interpret Deep Learning Models for Time Series Data

Accelerometers provide continuous measurements of human movements. Utilizing their data exhibits great potential for monitoring or predicting human health outcomes. In this direction, researchers are active in developing machine-learning algorithms. However, compared to understanding deep learning models, visualizing and interpreting such models is equally important but has been less well-developed. To address these limitations, we constructed an online software tool to visualize the hidden states inferred from the deep learning models and to compare different cohorts based on outcome-associated temporal profiles. We demonstrated the utility of the model using the National Health and Nutrition Examination Survey (NHANES) dataset. Using this tool, we discovered that two time periods of daily activity contribute to significant differences in 5-year mortalities. To disseminate the software to the broader community for the analysis of accelerometer data, we provide the work as open-source code at https://github.com/jyan97/HiddenVis.

bioinformatics↗

bioRxiv2020

Optimization of Spectral Library Size Improves DIA-MS Proteome Coverage

Efficient peptide and protein identification from data-independent acquisition mass spectrometric (DIA-MS) data typically rely on an experiment-specific spectral library with a suitable size. Here, we report a computational strategy for optimizing the spectral library for a specific DIA dataset based on a comprehensive spectral library, which is accomplished by a priori analysis of the DIA dataset. This strategy achieved up to 44.7% increase in peptide identification and 38.1% increase in protein identification in the test dataset of six colorectal tumor samples compared with the comprehensive pan-human library strategy. We further applied this strategy to 389 carcinoma samples from 15 tumor datasets and observed up to 39.2% increase in peptide identification and 19.0% increase in protein identification. In summary, we present a computational strategy for spectral library size optimization to achieve deeper proteome coverage of DIA-MS data.

bioinformatics↗

bioRxiv2020

Mechanism of negative regulation of NF-κB by N4BP1

Many immune responses depend upon activation of NF-{kappa}B, a key transcription factor in the elicitation of a cytokine response. Here we demonstrate that N4BP1 inhibited TLR-dependent activation of NF-{kappa}B by interacting with the NF-{kappa}B signaling essential modulator (NEMO, also known as I{kappa}B kinase {gamma}) to attenuate NEMO-NEMO dimerization or oligomerization. The UBA-like (ubiquitin associated-like) and CUE-like (ubiquitin conjugation to ER degradation) domains in N4BP1 mediated the interaction with the NEMO COZI domain. Both in vitro and in mice, N4bp1 deficiency specifically enhanced TRIF-independent (TLR2, TLR7, or TLR9-mediated), but not TRIF-dependent (TLR3 or TLR4-mediated), NF-{kappa}B activation leading to increased production of proinflammatory cytokines. In response to TLR4 or TLR3 activation, TRIF caused activation of caspase 8, which cleaved N4BP1 distal to residues D424 and D490 and abolished its inhibitory effect. N4bp1-/- mice also exhibited diminished numbers of T cells in the peripheral blood. Our work identifies N4BP1 as an inhibitory checkpoint protein that must be overcome to activate NF-{kappa}B, and a TRIF-initiated caspase 8-dependent mechanism by which this is accomplished.

immunology↗

bioRxiv2020

Neuronal Activity-Induced BRG1 Phosphorylation Regulates Enhancer Activation

Neuronal activity-induced enhancers drive the gene induction in response to stimulation. Here, we demonstrate that BRG1, the core subunit of SWI/SNF-like BAF ATP-dependent chromatin remodeling complexes, regulates neuronal activity-induced enhancers. Upon stimulation, BRG1 is recruited to enhancers in an H3K27Ac-dependent manner. BRG1 regulates enhancer basal activities and inducibility by affecting cohesin binding, enhancer-promoter looping, RNA polymerase II recruitment, and enhancer RNA expression. Furthermore, we identified a serine phosphorylation site in BRG1 that is induced by neuronal activities and is sensitive to CaMKII inhibition. BRG1 phosphorylation affects its interaction with several transcription co-factors, possibly modulating BRG1 mediated transcription outcomes. Using mice with knock-in mutations, we showed that non-phosphorylatable BRG1 fails to efficiently induce activity-dependent genes, whereas phosphomimic BRG1 increases the enhancer activities and inducibility. These mutant mice displayed anxiety-like phenotypes and altered responses to stress. Therefore, our data reveal a mechanism connecting neuronal signaling to enhancer activities through BRG1 phosphorylation.

molecular biology↗

bioRxiv2020

Limits to the cellular control of sequestered cryptophyte prey in the marine ciliate Mesodinium rubrum

The marine ciliate Mesodinium rubrum is famous for its ability to acquire and exploit chloroplasts and other cell organelles from some cryptophyte algal species. We sequenced genomes and transcriptomes of free-swimming Teleaulax amphioxeia, as well as well-fed and starved M. rubrum in order to understand cellular processes upon sequestration under different prey and light conditions. From its prey, the ciliate acquires the ability to photosynthesize as well as the potential to metabolize several essential compounds including lysine, glycan, and vitamins that elucidate its specific prey dependency. M. rubrum does not express photosynthesis related genes itself, but elicits considerable transcriptional control of the acquired cryptophyte organelles. This control is limited as light dependent transcriptional changes found in free-swimming T. amphioxeia got lost after sequestration. We found strong transcriptional rewiring of the cryptophyte nucleus upon sequestration, where 35% of the T. amphioxeia genes were significantly differentially expressed within well-fed M. rubrum. Qualitatively, 68% of all genes expressed within well-fed M. rubrum originated from T. amphioxeia. Quantitatively, these genes contributed up to 48% to the global transcriptome in well-fed M. rubrum and down to 11% in starved M. rubrum. This tertiary endosymbiosis system functions for several weeks, when deprived of prey. After this point in time, the ciliate dies if not supplied with fresh prey cells. M. rubrum represents one evolutionary way of acquiring photosystems from its algal prey, and might represent a step on the evolutionary way towards a permanent tertiary endosymbiosis.

evolutionary biology↗

bioRxiv2020

Growth, metabolism, and morphology of Akkermansia muciniphila grown in different nutrient media

As a kind of potential probiotic, Akkermansia muciniphila abundance in human body is directly causally related to obesity, diabetes, inflammation and abnormal metabolism. In this study, A. muciniphila dynamic cultures using five different media were implemented in an in vitro bionic intestinal reactor for the first time instead of the traditional static culture using brain heart infusion broth (BHI) or BHI + porcine mucin (BPM). The biomass under dynamic culture using BPM reached 1.92 g/L, which improved 44.36% compared with the value under static culture using BPM. The biomass under dynamic culture using human mucin (HM) further increased to the highest level of 2.89 g/L. Under dynamic culture using porcine mucin (PM) and HM, the main metabolites were short-chain fatty acids (acetic acid and butyric acid), while using other media, a considerable amount of branched-chain fatty acids (isobutyric and isovaleric acids) were produced. Under dynamic culture Using HM, the cell diameters reached 999 nm, and the outer membrane protein concentration reached the highest level of 26.26 g/mg. This study provided a preliminary theoretical basis for the development of A. muciniphila as the next generation probiotic.

microbiology↗

bioRxiv2020

Astrocytes express DMT1 and transferrin receptors, which transport iron thus activating Ca2+ signalling: possible role in neuroprotection against iron overload?

ABSTRACTIron is the fundamental element for numerous physiological functions. Reduced ferrous (Fe2+) and oxidized ferric (Fe3+) are the two ionized iron states in the living organisms. In the cell membrane, divalent metal ion transporter 1 (DMT1) is responsible for cellular uptake of Fe2+, whereas transferrin receptors (TFR) carry transferrin (TF)-bound Fe3+. In this study we performed, for the first time, detailed analysis of the action of Fe ions on cytoplasmic free calcium ion concentration ([Ca2+]i) in astrocytes. Using qPCR and immunocytochemistry we identified DMT1 and TFR in astrocytes in primary cultures, in acutely isolated astrocytes and in brain tissue preparations; in situ both DMT1 and TFR are concentrated in astroglial perivascular endfeet. Administration of Fe2+ or Fe3+ in low μM concentrations evoked Ca2+ signals in astrocytes in vitro and in vivo. Iron ions triggered increase in [Ca2+]i by acting through two distinct molecular cascades. Uptake of Fe2+ by DMT1 inhibited astroglial Na+-K+-ATPase (NKA), which led to an elevation in cytoplasmic Na+ concentration (as measured by SBFI probe), thus reversing Na+/Ca2+ exchanger (NCX) thereby generating Ca2+ influx. Uptake of Fe3+ by TF-TFR stimulated phospholipase C to produce inositol 1,4,5-trisphosphate (InsP3), thus trigering InsP3 receptor-mediated Ca2+ release from the endoplasmic reticulum. Iron-induced Ca2+ signals promote astroglial release of arachidonic acid and prostaglandin E2 cytokines by activating cytosolic phospholipase A2 (cPLA2) and NF-κB signalling cascade. In summary, these findings reveal new mechanisms of iron-induced astrocytic signalling operational in conditions of iron overload, in response to which astrocytes actively accumulate excessive iron and activate neuroprotective pathways.Competing Interest StatementThe authors have declared no competing interest.View Full Text

molecular biology↗

bioRxiv2020

Cryo-EM structure of C9ORF72-SMCR8-WDR41 reveals the role as a GAP for Rab8a and Rab11a

A massive intronic hexanucleotide repeat (GGGGCC) expansion in C9ORF72 is a genetic origin of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Recently, C9ORF72, together with SMCR8 and WDR41, has been shown to regulate autophagy and function as Rab GEF. However, the precise function of C9ORF72 remains unclear. Here, we report the cryo-EM structure of the human C9ORF72-SMCR8-WDR41 complex at a resolution of 3.2 [A]. The structure reveals the dimeric assembly of a heterotrimer of C9ORF72-SMCR8-WDR41. Notably, the C-terminal tail of C9ORF72 and the DENN domain of SMCR8 play critical roles in the dimerization of the two protomers of the C9ORF72-SMCR8-WDR41 complex. In the protomer, C9ORF72 and WDR41 are joined by SMCR8 without direct interaction. WDR41 binds to the DENN domain of SMCR8 by the C-terminal helix. Interestingly, the prominent structural feature of C9ORF72-SMCR8 resembles that of the FLNC-FNIP2 complex, the GTPase activating protein (GAP) of RagC/D. Structural comparison and sequence alignment revealed that Arg147 of SMCR8 is conserved and corresponds to the arginine finger of FLCN, and biochemical analysis indicated that the Arg147 of SMCR8 is critical to the stimulatory effect of the C9ORF72-SMCR8 complex on Rab8a and Rab11a. Our study not only illustrates the basis of C9ORF72-SMCR8-WDR41 complex assembly but also reveals the GAP activity of the C9ORF72-SMCR8 complex. Significance StatementC9ORF72, together with SMCR8 and WDR41, has been shown to form a stable complex that participates in the regulation of membrane trafficking. We report the cryo-EM structure of the C9ORF72-SMCR8-WDR41 complex at atomic resolution. Notably, the stoichiometry of the three subunits in the C9ORF72-SMCR8-WDR41 complex is 2:2:2. Interestingly, the C-termini of C9ORF72 and the DENN domain of SMCR8 mediate the dimerization of the two C9ORF72-SMCR8-WDR41 protomers in the complex. Moreover, WDR41 binds to the DENN domain of SMCR8 by the C-terminal helix without direct contact with C9ORF72. Most importantly, the C9ORF72-SMCR8 complex works as a GAP for Rab8a and Rab11a in vitro, and the Arg147 of SMCR8 is the arginine finger.

biochemistry↗

bioRxiv2020

HARMONIES: A Hybrid Approach for Microbiome Networks Inference via Exploiting Sparsity

The human microbiome is a collection of microorganisms. They form complex communities and collectively affect host health. Recently, the advances in next-generation sequencing technology enable the high-throughput profiling of the human microbiome. This calls for a statistical model to construct microbial networks from the microbiome sequencing count data. As microbiome count data are high-dimensional and suffer from uneven sampling depth, over-dispersion, and zero-inflation, these characteristics can bias the network estimation and require specialized analytical tools. Here we propose a general framework, HARMONIES, a Hybrid Approach foR MicrobiOme Network Inferences via Exploiting Sparsity, to infer a sparse microbiome network. HARMONIES first utilizes a zero-inflated negative binomial (ZINB) distribution to model the skewness and excess zeros in the microbiome data, as well as incorporates a stochastic process prior for sample-wise normalization. This approach infers a sparse and stable network by imposing non-trivial regularizations based on the Gaussian graphical model. In comprehensive simulation studies, HARMONIES outperformed four other commonly used methods. When using published microbiome data from a colorectal cancer study, it discovered a novel community with disease-enriched bacteria. In summary, HARMONIES is a novel and useful statistical framework for microbiome network inference, and it is available at https://github.com/shuangj00/HARMONIES.

bioinformatics↗

bioRxiv2020

A deep learning approach for tissue spatial quantification and genomic correlations of histopathological images

Epithelial and stromal tissue are components of the tumor microenvironment and play a major role in tumor initiation and progression. Distinguishing stroma from epithelial tissues is critically important for spatial characterization of the tumor microenvironment. We propose an image analysis pipeline based on a Convolutional Neural Network (CNN) model to classify epithelial and stromal regions in whole-slide images. The CNN model was trained using well-annotated breast cancer tissue microarrays and validated with images from The Cancer Genome Atlas (TCGA) project. Our model achieves a classification accuracy of 91.02%, which outperforms other state-of-the-art methods. Using this model, we generated pixel-level epithelial/stromal tissue maps for 1,000 TCGA breast cancer slide images that are paired with gene expression data. We subsequently estimated the epithelial and stromal ratios and performed correlation analysis to model the relationship between gene expression and tissue ratios. Gene Ontology enrichment analyses of genes that were highly correlated with tissue ratios suggest the same tissue was associated with similar biological processes in different breast cancer subtypes, whereas each subtype had its own idiosyncratic biological processes governing the development of these tissues. Taken all together, our approach can lead to new insights in exploring relationships between image-based phenotypes and their underlying genomic data and biological processes for all types of solid tumors.

bioinformatics↗

bioRxiv2020

Profiling the immune vulnerability landscape of the 2019 Novel Coronavirus

The outbreak of the 2019 Novel Coronavirus (SARS-CoV-2) rapidly spread from Wuhan, China to more than 150 countries, areas, or territories, causing staggering numbers of infections and deaths. In this study, bioinformatics analyses were performed on 5,568 complete genomes of SARS-CoV-2 virus to predict the T cell and B cell immunogenic epitopes of all viral proteins, which formed a systematic immune vulnerability landscape of SARS-CoV-2. The immune vulnerability and genetic variation profiles of SARS-CoV were compared with those of SARS-CoV and MERS-CoV. In addition, a web portal was developed to broadly share the data and results as a resource for the research community. Using this resource, we showed that genetic variations in SARS-CoV-2 are associated with loss of B cell immunogenicity, an increase in CD4+ T cell immunogenicity, and a minimum loss in CD8+ T cell immunogenicity, indicating the existence of a curious correlation between SARS-CoV-2 genetic evolutions and the immunity pressure from the host. Overall, we present an immunological resource for SARS-CoV-2 that could promote both therapeutic/vaccine development and mechanistic research.

bioinformatics↗

bioRxiv2020

On the origin and evolution of RNA editing in metazoans

Extensive adenosine-to-inosine (A-to-I) editing of nuclear-transcribed RNAs is the hallmark of metazoan transcriptional regulation, and is fundamental to numerous biochemical processes. Here we explore the origin and evolution of this regulatory innovation, by quantifying its prevalence in 22 species that represent all major transitions in metazoan evolution. We provide substantial evidence that extensive RNA editing emerged in the common ancestor of extant metazoans. We find the frequency of RNA editing varies across taxa in a manner independent of metazoan complexity. Nevertheless, cis-acting features that guide A-to-I editing are under strong constraint across all metazoans. RNA editing seems to preserve an ancient mechanism for suppressing the more recently evolved repetitive elements, and is generally nonadaptive in protein-coding regions across metazoans, except for Drosophila and cephalopods. Interestingly, RNA editing preferentially target genes involved in neurotransmission, cellular communication and cytoskeleton, and recodes identical amino acid positions in several conserved genes across diverse taxa, emphasizing broad roles of RNA editing in cellular functions during metazoan evolution that have been previously underappreciated.

evolutionary biology↗

bioRxiv2020

Characterization of the Intestinal Absorption of Morroniside from Cornus officinalis Sieb. et Zucc via a Caco-2 Cell Monolayer Model

Morroniside is biologically active polyphenols found in Cornus officinalis Sieb. et Zucc (CO) which exhibits a broad spectrum of pharmacological activities, such as protecting nerves, preventing diabetic liver damageand renal damage. However, little data is available regarding its mechanism ofintestinal absorption. Here, ahuman intestinal epithelial cell model Caco-2 cell in vitro cultured was applied to study on the absorption and transport of morroniside, the effects of time, donor concentration,pH, temperature and inhibitors,the absorption and transport of morroniside were investigated.The bidirectional permeability of morroniside from the apical (AP) to the basolateral (BL) side and in the revese direction was studied. When administrated was setat three tested concentrations (5, 25 and 100M), the P app value in AP-to-BL direction was ranged from 1.59 to 2.66x10 -6 cm/s. Inthe reverse direction, BL-to-AP, the value was ranged from 2.67to 4.10 x10 -6 cm/s.The data indicated that morroniside transport was both pH- and temperature- dependent. The morronisides permeability process affected bytreatment with various inhibitors, such as the multidrug resistance protein inhibitors MK571 and benzbromarone, the breast cancer resistance protein inhibitor apigenin.It can be found that the mechanisms of intestinal absorption of morroniside may involve multiple transport pathways like passive diffusion as well as efflux protein-mediated active transportespecially the multidrug resistance protein2 and breast cancer resistance protein.After CO was added, P app AB increased significantly by about 125.26%, it can therefore be assumed that some ingredients in the crude material promote morronisides absorption in the small intestine.

pharmacology and toxicology↗