Biology subjects

Tan, J.

Publications and source records attributed to Tan, J..

At least 163 records · Page 9Linked to original sources

bioRxiv2020

Autocrine IL11 cis-signaling in hepatocytes is an initiating nexus between lipotoxicity and non-alcoholic steatohepatitis

Background and aimsIL11 signaling is important in non-alcoholic steatohepatitis (NASH) but how it contributes to NASH pathologies beyond fibrosis is not known. Here we investigate the role of IL11 signaling in hepatocyte lipotoxicity. MethodsHepatocytes were stimulated with IL6, IL11, HyperIL6, or HyperIL11 alone or in the presence of soluble gp130 (sgp130) or soluble IL11RA (sIL11RA), or loaded with palmitate in the presence of IgG or anti-IL11RA (X209) antibodies or sgp130. Effects were assessed using colorimetric ALT, GSH, or ELISA assays, immunoblots, and flow cytometry. The relative contributions of IL11 cis-versus -trans signaling in vivo was assessed in two preclinical NASH models using a high fat methionine/choline deficient diet or a Western diet with liquid fructose in C57BL6/Ntac mice injected with AAV8-Alb-Cre, AAV8-Alb-sgp130, in mice with hepatocyte-specific deletion of Il11ra (CKO), and in mice with global deletion of Il11ra injected with AAV8-Alb-mIl11ra or AAV8-Alb-sIl11ra. Livers and serum were collected; serum samples were analyzed using biochemistry and liver tissues were analyzed by histology, qPCR, immunobloting, hydroxyproline, and GSH assays. ResultsWe show that lipid-laden hepatocytes secrete IL11, which acts via autocrine cis-signaling to cause lipoapoptosis. IL11 causes lipotoxic hepatocyte death through activation of non-canonical signaling pathways and increased NOX4-derived reactive oxygen species. In two preclinical models, hepatocyte-specific deletion of Il11ra1 protects mice from all aspects of NASH with beneficial effects on body weight. In accordance, restoration of IL11 cis-signaling in hepatocytes only in mice globally deleted for Il11ra1 reconstitutes steatosis and inflammation. Throughout, we found no evidence to support the existence of IL6 or IL11 trans-signaling in the liver. ConclusionWe conclude that autocrine IL11-mediated cell death underlies hepatocyte lipotoxicity and that liver fibrosis and inflammation occur subsequently. These data highlight a new disease mechanism for the transition from compensated fatty liver disease to NASH.

molecular biology↗

bioRxiv2020

PCV2 aggravated SS2 infection directly showed from differentially expressed proteome of PK15 cells.

PCV2 and SS2 were clinically two major pathogens in pigs and they were zoonotic pathogens. There was extensive cellular tropism for both PCV2 and SS2, as well as, PK15 cells was PCV2 infection mainly cell model. It was found that when PCV2 infected PK15 cells before at the MOI=0.1, SS2 could cause more damage to PK15 cells. ITRAQ labeling proteomic technology was used to explore the differentially expressed proteome of PCV2 and SS2 single infection and co-infection in PK15 cells. The results showed that there were total 4736 proteins distinct changed in this infection models for PK15 cells. PCV2 aggravated SS2 infection were showed directly in the big amount of differentially expressed proteins like AGO3, OSBPL1A, ALB, RIC8A, UBL4A, INTS5 and so on. For the KEGG pathway analysis, it indicated that PCV2 mainly induced the proteins lessen though a series of disease pathway like metabolic pathways, huntingtons disease, insulin signaling pathways, long-term depression, etc. to make cell at a state of compensation. PCV2 before infection made the cells was on the chopping block. Contemporary, SS2 induced the proteins of PK15 rapidly changing, including pathways like spliceosome, endoplasmic reticulum, tight junction, actin cytoskeleton and some involved in parasitic infections pathways like ECM-receptor interaction, Leishmaniasis, Toxoplasmosis and so on. Simultaneously, PCV2 and SS2 existed common ground that they influence PK15 cell by some virulence factor interacted with cytomembrane, influenced the function of ribosome and tRNA. The role of SS2 in the co-infection like a cook chopper.

microbiology↗

bioRxiv2020

MiRNAs profiling and degradome sequencing between the CMS-line N816S and its maintainer line Ning5m during anther development in pepper (Capsicum annuum L.)

Utilization of cytoplasmic male sterility (CMS) is significant for agriculture. MiRNAs are a class of endogenously non-coding small RNAs (21-24 nt) that play key roles in the regulation of various growth and developmental processes in plants. The knowledge miRNA-guided CMS regulation is rather limited in pepper. To better understand the miRNAs involvement and regulatory mechanism of CMS, miRNA libraries from anther of CMS-line N816S and its maintainer line Ning5m were generated by miRNAome sequencing in pepper. A total of 76 differentially expressed miRNAs were detected, of which 18 miRNAs were further confirmed by quantitative real-time PCR (qRT-PCR). In addition, miRNA targets were identified by degradome sequencing. The result showed that 1292 targets that were potentially cleaved by 321 miRNAs (250 conserved miRNAs and 71 novel miRNAs). Gene Ontology (GO) and KEGG pathway analysis indicated that 35 differentially expressed miRNAs might play roles in the regulation of CMS sterility, by cleaving 77 target transcripts, such as MYBs, SPLs, and AFRs, of which targeted by miR156, miR167, miRNA858 family. Nineteen miRNA-cleaved targets were selectively examined by qRT-PCR, and the results showed that there were mostly negative correlations between miRNAs and their targets on the expression level. These findings provide a valuable information to understand miRNAs mechanism during anther development and CMS occurrence in pepper.

plant biology↗

bioRxiv2020

Host and infectivity prediction of Wuhan 2019 novel coronavirus using deep learning algorithm

The recent outbreak of pneumonia in Wuhan, China caused by the 2019 Novel Coronavirus (2019-nCoV) emphasizes the importance of detecting novel viruses and predicting their risks of infecting people. In this report, we introduced the VHP (Virus Host Prediction) to predict the potential hosts of viruses using deep learning algorithm. Our prediction suggests that 2019-nCoV has close infectivity with other human coronaviruses, especially the severe acute respiratory syndrome coronavirus (SARS-CoV), Bat SARS-like Coronaviruses and the Middle East respiratory syndrome coronavirus (MERS-CoV). Based on our prediction, compared to the Coronaviruses infecting other vertebrates, bat coronaviruses are assigned with more similar infectivity patterns with 2019-nCoVs. Furthermore, by comparing the infectivity patterns of all viruses hosted on vertebrates, we found mink viruses show a closer infectivity pattern to 2019-nCov. These consequences of infectivity pattern analysis illustrate that bat and mink may be two candidate reservoirs of 2019-nCov.These results warn us to beware of 2019-nCoV and guide us to further explore the properties and reservoir of it. One Sentence SummaryIt is of great value to identify whether a newly discovered virus has the risk of infecting human. Guo et al. proposed a virus host prediction method based on deep learning to detect what kind of host a virus can infect with DNA sequence as input. Applied to the Wuhan 2019 Novel Coronavirus, our prediction demonstrated that several vertebrate-infectious coronaviruses have strong potential to infect human. This method will be helpful in future viral analysis and early prevention and control of viral pathogens.

systems biology↗

bioRxiv2019

Organogenesis and Distribution of the Ocular Lymphatic Vessels in the Anterior Eye: Implication to Glaucoma Surgery Site Selection

Glaucoma surgeries, such as trabeculectomy, are performed to lower the intraocular pressure to reduce the risk of vision loss. The surgeries create a new passage in the eye that reroutes the aqueous humor outflow to the subconjunctival space, where the fluid is presumably absorbed by the conjunctival lymphatics. However, the current knowledge of these ocular surface lymphatics remains limited. Here, we characterized the biology and function of the ocular lymphatics using transgenic lymphatic reporter mice and rats. We found that the limbal and conjunctival lymphatic networks are progressively formed by a primary lymphatic vessel that grows out from the nasal-side medial canthus region at the time of birth. This primary lymphatic vessel immediately branches out and invades the limbus and conjunctiva, and then simultaneously encircles the cornea in a bidirectional manner. As a result, the distribution of the ocular lymphatic is significantly polarized toward the nasal side, and the limbal lymphatics are directly connected to the conjunctival lymphatics. New lymphatic spouts are mainly produced from the nasal-side limbal lymphatics, posing the nasal side of the eye more responsive to fluid drainage and inflammatory stimuli. Consistently, when a fluorescent tracer was injected, fluid clearance was much more efficient in the nasal side than the temporal side of the eyes. In comparison, blood vessels are evenly distributed on the front surface of the eyes. We found that these distinct vascular distribution patterns were also conserved in human eyes. Together, our study demonstrated that the ocular surface lymphatics are more densely present in the nasal side and uncovered the potential clinical benefits in selecting the nasal side as a surgical site for glaucoma surgeries to improve the fluid drainage.

developmental biology↗

bioRxiv2019

Redefining Interleukin 11 as a regeneration-limiting hepatotoxin

Acetaminophen (APAP) overdose is a leading cause of untreatable liver failure. In the mouse model of APAP-induced liver injury (AILI), the administration of recombinant human interleukin 11 (rhIL11) is protective. Here we show that the beneficial effect of rhIL11 in the mouse is due to its unexpected and paradoxical inhibition of endogenous mouse IL11 activity. Contrary to the accepted paradigm IL11 is a potent hepatotoxin across species, which is secreted from damaged hepatocytes to drive an autocrine loop of NOX4 and JNK-dependent apoptosis. Mice with hepatocyte-specific Il11 expression spontaneously develop liver failure whereas those with Il11ra1 deletion are remarkably protected from AILI. Neutralizing anti-IL11R antibodies administered to moribund mice 10 hours following a lethal APAP overdose results in 90% survival that is associated with very large liver regeneration. Our data overturn a misconception, identify a new disease mechanism and suggest IL11 as a therapeutic target for liver regeneration.

physiology↗

bioRxiv2019

Fibroblast-specific IL11 signaling is required for lung fibrosis and inflammation

Tissue injury leads to activation of resident stromal, parenchymal and immune cells to initiate reparative processes that, if unresolved, can lead to fibrosis and organ damage. The directionality of effect between fibrosis and inflammation in the lung has been a point of debate for many years. Here, we tested the hypothesis that Interleukin 11 (IL11) signaling in fibroblasts is of primary importance for pulmonary fibrosis and that this event is upstream of lung inflammation. We generated mice with loxP-flanked Il11ra1 alleles and crossed them to a Col1a2-CreERT strain to enable Il11ra1 deletion in adult fibroblasts (Il11ra1-CKO mice). Lung fibroblasts from Il11ra1-CKO mice were selectively deleted for Il11ra1 and refractory to TGF{beta}1 stimulation. In the mouse model of bleomycin-induced lung fibrosis, Il11ra1-CKO mice had markedly reduced pulmonary fibrosis and lesser lung damage, which was accompanied by diminished ERK activation in the stromal compartment. Bleomycin lung injury in Il11ra1-CKO mice was also associated with diminished STAT3 activation in inflammatory cells, fewer pulmonary immune cell infiltrates and almost complete inhibition of NF-kB activation. These data reveal an essential role for IL11 signaling in fibroblasts for lung fibrosis and show that inflammation in the lung can be secondary to stromal activation.

cell biology↗

bioRxiv2019

Experimental evolution reveals the genetic basis and systems biology of superoxide stress tolerance

Bacterial response to oxidative stress is of fundamental importance. Oxidative stresses are endogenous, such as reactive oxidative species (ROS) production during respiration, or exogenous in industrial biotechnology, due to culture conditions or product toxicity. The immune system inflicts strong ROS stress on invading pathogens. In this study we make use of Adaptive Laboratory Evolution (ALE) to generate two independent lineages of Escherichia coli with increased tolerance to superoxide stress by up to 500% compared to wild type. We found: 1) that the use of ALE reveals the genetic basis for and systems biology of ROS tolerance, 2) that there are only 6 and 7 mutations, respectively, in each lineage, five of which reproducibly occurred in the same genes (iron-sulfur cluster regulator iscR, putative iron-sulfur repair protein ygfZ, pyruvate dehydrogenase subunit E aceE, succinate dehydrogenase sucA, and glutamine tRNA glnX), and 3) that the transcriptome of the strain lineages exhibits two different routes of tolerance: the direct mitigation and repair of ROS damage and the up-regulation of cell motility and swarming genes mediated through phosphate starvation, which has been linked to biofilm formation and aggregation. These two transcriptomic responses can be interpreted as flight and fight phenotypes.\n\nImportanceBacteria encounter oxidative stress from multiple sources. During pathogenic infections, our bodys immune system releases ROS as a form of antimicrobial defense whilst bacteria used in industrial biotechnology are frequently exposed to genetic modifications and culture conditions which induce oxidative stress. In order to get around the bodys defences, pathogens have developed various adaptations to tolerate high levels of ROS, and these adaptive mechanisms are not always well understood. At the same time, there is a need to improve oxidative stress tolerance for industrially relevant strains in order to increase robustness and productivity. In this study we generate two strains of superoxide tolerant Escherichia coli and identify several adaptive mechanisms. These findings can be directly applied to improve production strain fitness in an industrial setting. They also provide insight into potential virulence factors in other pathogens, highlighting potential targets for antimicrobial compounds.

systems biology↗

bioRxiv2019

Heart Rate n-Variability (HRnV) and Its Application to Risk Stratification of Chest Pain Patients in the Emergency Department

BackgroundChest pain is one of the most common complaints among patients presenting to the emergency department (ED). Causes of chest pain can be benign or life threatening, making accurate risk stratification a critical issue in the ED. In addition to the use of established clinical scores, prior studies have attempted to create predictive models with heart rate variability (HRV). In this study, we proposed heart rate n-variability (HRnV), an alternative representation of beat-to-beat variation in electrocardiogram (ECG) and investigated its association with major adverse cardiac events (MACE) for ED patients with chest pain. MethodsWe conducted a retrospective analysis of data collected from the ED of a tertiary hospital in Singapore between September 2010 and July 2015. Patients >20 years old who presented to the ED with chief complaint of chest pain were conveniently recruited. Five to six-minute single-lead ECGs, demographics, medical history, troponin, and other required variables were collected. We developed the HRnV-Calc software to calculate HRnV parameters. The primary outcome was 30-day MACE, which included all-cause death, acute myocardial infarction, and revascularization. Univariable and multivariable logistic regression analyses were conducted to investigate the association between individual risk factors and the outcome. Receiver operating characteristic (ROC) analysis was performed to compare the HRnV model (based on leave-one-out cross-validation) against other clinical scores in predicting 30-day MACE. ResultsA total of 795 patients were included in the analysis, of which 247 (31%) had MACE within 30 days. The MACE group was older and had a higher proportion of male patients. Twenty-one conventional HRV and 115 HRnV parameters were calculated. In univariable analysis, eleven HRV parameters and 48 HRnV parameters were significantly associated with 30-day MACE. The multivariable stepwise logistic regression identified 16 predictors that were strongly associated with the MACE outcome; these predictors consisted of one HRV, seven HRnV parameters, troponin, ST segment changes, and several other factors. The HRnV model outperformed several clinical scores in the ROC analysis. ConclusionsThe novel HRnV representation demonstrated its value of augmenting HRV and traditional risk factors in designing a robust risk stratification tool for patients with chest pain at the ED.

bioengineering↗

bioRxiv2019

Trimester-specific Zika virus infection affects placental responses in women

Zika virus (ZIKV) infection during pregnancy is associated with neurologic birth defects, but the effects on placental development are unclear. Full-term placentas from three women, each infected with ZIKV during specific pregnancy trimesters, were harvested for anatomic, immunologic and transcriptomic analysis. In this study, each woman exhibited a unique immune response, but they collectively diverged from healthy controls with raised IL-1RA, IP-10, EGF and RANTES expression, and neutrophil numbers during the acute infection phase. Although ZIKV NS3 antigens co-localized to placental Hofbauer cells, the placentas showed no anatomical defects. Transcriptomic analysis of samples from the placentas revealed that infection during trimester 1 caused a disparate cellular response centered on differential eIF2 signaling, mitochondrial dysfunction and oxidative phosphorylation. These findings should translate to improve clinical prenatal screening procedures for virus-infected pregnant patients.

immunology↗

bioRxiv2019

Genome-wide Association study of facial morphology identifies novel genetic loci in Han Chinese

Human face is a heritable surface with many complex sensory organs. In recent years, many genetic loci associated with facial features have been reported in different populations, yet there is a lack for the Han Chinese population. We report a genome-wide association analysis of 3D normal human faces in 2659 Han Chinese with two groups of phenotypes, the partial and whole face phenotypes and the distance and angle phenotypes. We found significant signals in five genomic regions with traits related to nose or eyes, including rs970797 in 2q31.1 near HOXD1 and MTX2, rs16897517 in 8q22.2 at intron of VPS13B, rs9995821 in 4q31.3 near DCHS2 and SFRP2, rs12636297 in 3q23 near PISRT1, and rs12948076 in 17q24.3 near SOX9 and CASC17. We visualized changes in facial morphology by comparing the volume of local areas and observed that these nose-related loci were associated with different features of the nose, including nose prominence, nasion height, and nostril shape, suggesting that the nose underlies precise genetic regulation. These results provide a more comprehensive understanding of the relationship between genetic loci and human facial morphology.\n\nAuthor SummaryHuman face as a combination of delicate sensory organs has a strong genetic component, as evidenced by the identical appearance in twins and shared facial features in close relatives. Although facial genetics have been studied in different populations, our knowledge between genetic markers with facial features is still limited. In this paper, we found genetic variants associated with nose and eyes through a large-scale high-resolution 3D facial genetic study on the Han Chinese population. We observed that these nose-related loci were associated with different features of the nose, including nose prominence, nasion height, and nostril shape, which suggests the nose underlies precise genetic regulation. Intriguingly, we noted that genes (DCHS2 and SFRP2) related to one of these loci are differentially expressed in human and chimp cranial neural crest cells, which plays a crucial role in the early formation of facial morphology. The ongoing genetic studies of facial morphology will improve our understanding of human craniofacial development, and provide potential evolution evidence of human facial features.

genetics↗

bioRxiv2019

Differentiation of Urine-Derived Induced Pluripotent Stem Cells to Neuron, Astrocyte and Microvascular Endothelial Cells from a Diabetic Patient

BackgroundComplications of central nervous system (CNS) in type 2 diabetes mellitus (T2DM) often lead to cognitive impairment and seriously affect the quality of life. However, there is no individualized disease model. Urinary epithelial cells (UECs) can be an ideal source for generating human induced pluripotent stem cells (hiPSCs) and progenitors, as they are easily accessible, non-invasive and universally available. Therefore, we intended to differentiate urine-derived hiPSCs into neuron (N), astrocyte (A) and microvascular endothelial cells (E) from a T2DM patient for future study its pathogenesis and precision medical treatment.\n\nMethods and ResultshiPSCs was successfully induced from UECs using integration free Sendai virus technology in a totally noninvasive manner. It had a normal karyotype (46, XY) and were proved to be pluripotent by immunofluorescence staining, alkaline phosphatase staining, karyotyping, teratoma experiments and methylated analysis. N, A and E were successfully induced and displayed typical morphological characteristics.\n\nConclusionsThis study indicates that N, A, E can be generated from urine-derived hiPSCs. Then we intend to create a new disease model in vitro to simulate the cerebral microenvironment of DM which will provide new methods for further investigate the disease-specific mechanisms.

cell biology↗

bioRxiv2019

iRhom2 serves as a facilitator in obesity by enhancing adipose inflammation and insulin resistance

Chronic inflammation of adipose tissues contributes to obesity-triggered insulin resistance. Unfortunately, the potential molecular mechanisms regarding obesity associated systemic inflammation and metabolic disorder remain complicated. Here we display that inactive rhomboid-like protein 2 (iRhom2) is increased in mice fat with adipose inflammation. After 16 weeks on a high fat diet (HFD), obesity, chronic inflammation in adipose tissues and insulin resistance are markedly mitigated in iRhom2-knockout (iRhom2 KO) mice, but exaggerated in iRhom2-overactivated mice. The adverse impressions of iRhom2 on adipose inflammation and associated pathologies are determined in db/db mice. Also, we further exhibit that in response to HFD, iRhom2 KO mice and mice with deletion only in myeloid cells showed less severe adipose inflammation and insulin resistance than the control groups. Conversely, transplantation of bone marrow cells from normal mice to iRhom2 KO mice unleashed the severity of systemic inflammation and metabolic dysfunction after HFD ingestion. In conclusion, we identify iRhom2 as a key regulator that promotes obesity-associated metabolic disorder. Loss of iRhom2 from macrophages in adipose tissues inhibited the inflammation and insulin resistance. iRhom2 might be a therapeutic target for obesity-induced metabolic dysfunction.\n\nSignificanceIncreased inactive rhomboid-like protein 2 signaling has recently been shown to trigger inflammation-associated activation of innate immune responses. Herein we investigate that this signal also plays a crucial role in obesity-triggered adipose tissue inflammation infiltration and metabolic disorder, beyond the well-known assignment in innate immune supervision. Also, we have reported the iRhom2 as a key promoter in regulating metabolic function, which enhances obesity-stimulated inflammation and systemic insulin resistance by up regulation of macrophages pro-inflammatory activation. Our current study indicates that targeting the iRhom2 signaling in adipose tissues could possibly be an efficient strategy to mitigating obesity-associated systemic inflammation and metabolic dysfunction.

pathology↗

bioRxiv2019

Identification of 67 pleiotropic genes for seven autoimmune diseases using multivariate statistical analysis

Although genome-wide association studies (GWAS) have a dramatic impact on susceptibility locus discovery, this univariate approach has limitation in detecting complex genotype-phenotype correlations. It is essential to identify shared genetic risk factors acting through common biological mechanisms of autoimmune diseases with a multivariate analysis. In this study, the GWAS summary statistics including 41,274 single nucleotide polymorphisms (SNPs) located in 11,516 gene regions was analyzed to identify shared variants of seven autoimmune diseases using metaCCA method. Gene-based association analysis was used to refine the pleiotropic genes. In addition, GO term enrichment analysis and protein-protein interaction network analysis were applied to explore the potential biological function of the identified genes. After metaCCA analysis, 4,962 SNPs (P<1.21x10-6) and 1,044 pleotropic genes (P<4.34x10-6) were identified. By screening the results of gene-based p-values, we identified the existence of 27 confirmed pleiotropic genes and highlighted 40 novel pleiotropic genes which achieved significance threshold in metaCCA analysis and were also associated with at least one autoimmune disease in the VEGAS2 analysis. The metaCCA method could identify novel variants associated with complex diseases incorporating different GWAS datasets. Our analysis may provide insights for some common therapeutic approaches of autoimmune diseases based on the pleiotropic genes and common mechanisms identified. Author summaryAlthough previous researches have clearly indicated varying degrees of overlapping genetic sensitivities in autoimmune diseases, it has proven GWAS only explain small percent of heritability. Here, we take advantage of recent technical and methodological advances to identify pleiotropic genes that act on common biological mechanisms and the overlapping pathophysiological pathways of autoimmune diseases. After selection using multivariate analysis and verification using gene-based analyses, we successfully identified a total of 67 pleiotropic genes and performed the functional term enrichment analysis. In particularly, 27 genes were identified to be pleiotropic in previous different types of studies, which were validated by our present study. Forty significant genes (16 genes were associated with one disease earlier, and 24 were novel) might be the novel pleiotropic candidate genes for seven autoimmune diseases. The improved detection not only yielded the shared genetic components but also provided better understanding for exploring the potential common biological pathogenesis of these major autoimmune diseases.

genetics↗

bioRxiv2018

Motion-in-depth perception and prey capture in the praying mantis

Perceiving motion-in-depth is essential to detecting approaching or receding objects, predators and prey. This can be achieved using several cues, including binocular stereoscopic cues such as changing disparity and interocular velocity differences and monocular cues such as looming. While these have been studied in detail in humans, only looming responses have been well characterized in insects and we know nothing about the role that stereo cues play and how they might interact with looming cues. We used our 3D insect cinema in a series of experiments to investigate the role of the stereo cues mentioned above, as well as looming, in the perception of motion-in-depth during predatory strikes by the praying mantis. Our results show that motion-in-depth does increase the probability of mantis strikes but only for the classic looming stimulus, an expanding luminance edge. Approach indicated by radial motion of a texture or expansion of a motion-defined edge, or by stereoscopic cues, all failed to elicit increased striking. We conclude that mantises use stereopsis to detect depth but not motion-in-depth, which is detected via looming.\n\nSummary StatementBoth stereoscopic visual cues and changing luminance cues can enable detection of approaching objects. We show that mantises use looming rather than stereo cues to detect motion-in-depth.

animal behavior and cognition↗

bioRxiv2018

IL-11 neutralising therapies target hepatic stellate cell-induced liver inflammation and fibrosis in NASH

The transformation of hepatic stellate cells (HSCs) into myofibroblasts is the defining pathobiology in non-alcoholic steatohepatitis (NASH). Here we show that key NASH factors induce IL-11, which drives an autocrine and ERK-dependent activation loop to initiate and maintain HSC-to-myofibroblast transformation, causing liver fibrosis. IL-11 is upregulated in NASH and Il11ra1-deleted mice are strongly protected from liver fibrosis, inflammation and steatosis in murine NASH. Therapeutic inhibition of IL11RA or IL-11 with novel neutralizing antibodies robustly inhibits NASH pathology in preclinical models and reverses established liver fibrosis by promoting HSC senescence and favourable matrix remodelling. When given early in NASH, IL-11 inhibition prevents liver inflammation and steatosis, reverses severe hepatocyte damage and reduces hepatic immune cells and TGF{beta}1 levels. Our findings show an unappreciated and central role for IL-11 in HSCs and prioritise IL-11 signalling as a new therapeutic target in NASH while revealing an unexpected pro-inflammatory function for IL-11 in stromal immunity.

molecular biology↗

bioRxiv2018

Bacterial T6SS Effector EvpP Inhibits Neutrophil Recruitment via Jnk-Caspy Inflammasome Signaling In vivo

The type VI secretion system (T6SS) comprises dynamic complex bacterial contractile nanomachines and is used by many bacteria to inhibit or kill other prokaryotic or eukaryotic cells. Previous studies have revealed that T6SS is constitutively active in response to various stimuli, or fires effectors into host cells during infection. It has been proposed that the T6SS effector EvpP in Edwardsiella piscicida can inhibit NLRP3 inflammasome activation via the Ca2+-dependent JNK pathways. Here, we developed an in vivo infection model by microinjecting bacteria into the tail vein muscle of 3-day-post-fertilized zebrafish larvae, and found that both macrophages and neutrophils are essential for bacterial clearance. Further study revealed that EvpP plays a critical role in promoting the pathogenesis of E. piscicida via inhibiting the phosphorylation of Jnk signaling to reduce the expression of cxcl8a, mmp13 and IL-1{beta} in vivo. Subsequently, by utilizing Tg (mpo:eGFP+/+) zebrafish larvae for E. piscicida infection, we found that the EvpP-inhibited Jnk-caspy inflammasome signaling axis significantly suppressed the recruitment of neutrophils to infection sites, and the caspy- or IL-1{beta}-MO knockdown larvae were more susceptible to infection and failed to restrict bacterial colonization in vivo.\n\nIMPORTANCEInnate immunity is regulated by phagocytic cells and is critical for host control of bacterial infection. In many bacteria, T6SSs can affect bacterial virulence in certain environments, but little is known about the mechanisms underlying T6SS regulation of innate immune responses during infection in vivo. Here, we investigated the role of an E. piscicida T6SS effector EvpP in manipulating the reaction of neutrophils in vivo. We show that EvpP inhibits the activation of Jnk-caspy inflammasome pathway in zebrafish larvae, and reveal that macrophages are essential for neutrophil recruitment in vivo. This interaction improves our understanding about the complex and contextual role of a bacterial T6SS effector in modulating the action of myeloid cells during infection, and offers new insights into the warfare between bacterial weapons and host immunological surveillance.

microbiology↗

bioRxiv2018

Translational control of cardiac fibrosis

Abstract BackgroundFibrosis is a common pathology in many cardiac disorders and is driven by the activation of resident fibroblasts. The global post-transcriptional mechanisms underlying fibroblast-to-myofibroblast conversion in the heart have not been explored.\n\nMethodsGenome-wide changes of RNA transcription and translation during human cardiac fibroblast activation were monitored with RNA sequencing and ribosome profiling. We then used miRNA-and RNA-binding protein-based analyses to identify translational regulators of fibrogenic genes. To reveal post-transcriptional mechanisms in the human fibrotic heart, we then integrated our findings with cardiac ribosome occupancy levels of 30 dilated cardiomyopathy patients.\n\nResultsWe generated nucleotide-resolution translatome data during the TGF{beta}1-driven cellular transition of human cardiac fibroblasts to myofibroblasts. This identified dynamic changes of RNA transcription and translation at several time points during the fibrotic response, revealing transient and early-responder genes. Remarkably, about one-third of all changes in gene expression in activated fibroblasts are subject to translational regulation and dynamic variation in ribosome occupancy affects protein abundance independent of RNA levels. Targets of RNA-binding proteins were strongly enriched in post-transcriptionally regulated genes, suggesting genes such as MBNL2 can act as translational activators or repressors. Ribosome occupancy in the hearts of patients with dilated cardiomyopathy suggested an extensive post-transcriptional regulatory network underlying cardiac fibrosis. Key network hubs include RNA-binding proteins such as PUM2 and QKI that work in concert to regulate the translation of target transcripts in human diseased hearts.\n\nConclusionsWe reveal widespread translational effects of TGF{beta}1 and define novel post-transcriptional events that control the fibroblast-to-myofibroblast transition. Regulatory networks that affect ribosome occupancy in fibroblasts are paralleled in human heart disease. Our findings show the central importance of translational control in fibrosis and highlight novel pathogenic mechanisms in heart failure.

genomics↗