Five genes identified as prognostic markers for colorectal cancer through the integration of genome-wide association study and expression quantitative trait loci data.

Background: Colorectal cancer (CRC) is a prominent form of cancer globally, ranking second in terms of prevalence and serving as a leading cause of cancer-related deaths, but the underlying biological interpretation remains largely unknown. Methods: We used the summary data-based Mendelian randomization method to integrate CRC genome-wide association studies (ncase = 7062; ncontrol = 195,745) and expression quantitative trait loci summary data in peripheral whole blood (Consortium for Architecture of Gene Expression: n = 2765; Genotype-Tissue Expression [v8]: n = 755) and colon tissue (colon-transverse: n = 406; colon-sigmoid: n = 373) and identified related genes. Results: Genes ABTB1, CYP21A2, NLRP1, PHKG1 and PIP5K1C have emerged as significant prognostic markers for CRC patient survival. Functional analysis revealed their involvement in cancer cell migration and invasion mechanisms, providing valuable insights for the development of future anti-CRC drugs. Conclusion: We successfully identified five CRC risk genes, providing new insights and research directions for the effective mechanisms of CRC.

[Box: see text].

Design, optimization and application of reformer in a marine natural gas engine: A numerical and experimental study.

In the present study, the models of flow, heat transfer and reforming of 2-D single reforming tube and 3-D reformer core inside the reformer were implemented by CFD. The models were evaluated by comparison of simulations with data derived from a catalytic packed-bed reactor. In addition, a NG engine-reformer experimental system was established. Thereby, the experimental studies on performance of the reformer and engine under different excess air coefficient (λ), exhaust gas recirculation rate (XEGR) and reformed NG supply (CH4/O2, M/O value) were conducted based on IMO Tier III and China II emission standards. The results showed that oxidation and steam reforming reactions of methane were dominant in the process of exhaust gas-methane reforming and had obvious reaction sequence. For the reformer optimization, the design parameters were determined: GHSV = 16,000 h-1 and L/D = 7 for single reforming tube; diffuse angle of 30° and one deflector for reformer core. Besides, for experiments of REGR system, the reformer should operate under the condition of near M/O = 2-2.5 and XEGR = 7.3 % with high λ to achieve an optimal H2 yield and efficient H2 production. Compared with original engine under 50 % load and XEGR = 10.4 %, the brake thermal efficiency of the engine with REGR was increased by the maximum of 0.7 % (λ = 1.31). Noted that the maximum 85.5 % reduction of HC + NOx and the minimum 64.1 % treatment rate of CH4 could be obtained for meeting China II at λ = 1.25. Under different propeller loads, HC + NOx and CO emissions could both satisfy IMO Tier III and China II standards via adjusting the matched strategy of λ and XEGR. To meet fully China II standard, the minimum treatment rate of CH4 by the post-treatment unit needed to reach 79 %, 64 % and 64 % at 25 %, 50 % and 75 % load, respectively.

Gomisin N attenuated cerebral ischemia-reperfusion injury through inhibition of autophagy by activating the PI3K/AKT/mTOR pathway.

BACKGROUND: Ischemic stroke is a major global cause of mortality and permanent disability.  Studies have shown that autophagy is essential to maintain cell homeostasis and inevitably lead to neuronal damage after cerebral ischemia. Gomisin N (GN), lignin isolated from Schisandra chinensis, possesses multiple pharmacological activities. However, there is no research on the potential of GN for neuroprotection in ischemic stroke. PURPOSE: The current work aimed to explore the potential therapeutic possibilities of GN on ischemic stroke and investigate the underlying molecular mechanisms. STUDY DESIGN: The neuroprotective effects of GN on PC12 cells induced by oxygen glucose deprivation/reoxygenation (OGD/R) and mice with middle cerebral artery occlusion/reperfusion (MCAO/R) injury were investigated. METHODS: On day 3 after ischemia, the infarct volume and neurological function were assessed. The level of autophagy was measured in vivo and in vitro using Transmission electron microscopy (TEM) and Monodansylcadaverine (MDC) staining. The interaction between GN and PI3K/AKT/mTOR pathway was investigated by molecular docking. Additionally, the expressions of critical proteins in the PI3K/AKT/mTOR signaling pathway and autophagy markers were determined by western blotting. RESULTS: In compared to the Model group, GN might considerably improve the neurological and locomotor function following a stroke, as well as lower the volume of the cerebral infarct volume and the number of autophagosomes. GN therapy may suppress autophagy by activating the PI3K/Akt/mTOR signaling pathway in the penumbra. In vitro, MDC and TEM results showed that GN treatment obviously suppressed autophagy. Meanwhile, GN downregulated LC3II/LC3I expression ratio while upregulated the p62 expression level. In further studies, GN dramatically boosted the expression ratios of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR proteins in PC12 cells following OGD/R damage. However, the PI3K inhibitor (LY294002) reversed the increase of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR expression ratio induced by GN administration. Also, LY294002 significantly partially attenuated GN induced reduction of autophagy and increase of cell viability compared with GN treatment alone. CONCLUSIONS: Here, we first demonstrate the neuroprotective effects of GN on MCAO mice and OGD/R induced PC12 cells injury. A possible mechanism by which GN prevents ischemic stroke is proposed: GN could restrain autophagy by stimulating the PI3K/AKT/mTOR signaling pathways. More effects and mechanisms of GN on the rehabilitation of ischemic stroke are worthy to be explored in the future.

Mn Pretreatment Improves the Physiological Resistance and Root Exudation of Celosia argentea Linn. to Cadmium Stress.

Phytoextraction using Celosia argentea Linn. by Mn pretreatment can potentially decontaminate Cd-contaminated soils. However, the mechanism that accelerates the Cd bioaccumulation is still unknown. In order to study the effect and mechanism of Mn pretreatment on Cd bioaccumulation in C. argentea, the hydroponic experiments were set to determine the chlorophyll content, antioxidant enzyme activity, malondialdehyde content, and root exudation of C. argentea. The results indicated that after seven days of Mn pretreatment, both the biomass and Cd concentrations in plants increased compared to the control group. One of the mechanisms for this was the improvement in the physiological resistance of C. argentea following pretreatment with Mn. Compared with Cd stress alone, Mn pretreatment increased photosynthesis and reduced membrane lipid peroxidation. Meanwhile, the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were significantly reduced in leaves of C. argentea after Mn pretreatment through the reduction in the production of reactive oxygen species. In addition, Mn promoted the exudation of organic acids in the roots of C. argentea. The contents of citric and malic acids increased by 55.3% and 26.4%, respectively, which may be another important reason for Mn pretreatment increasing Cd bioaccumulation in C. argentea. Therefore, the present work shows that the pretreatment of seedlings with Mn can provide a meaningful strategy to improve the remediation efficiency of Cd-contaminated soils by C. argentea.

Targeting Oxidative Stress in Intracerebral Hemorrhage: Prospects of the Natural Products Approach.

Intracerebral hemorrhage (ICH), the second most common subtype of stroke, remains a significant cause of morbidity and mortality worldwide. The pathological mechanism of ICH is very complex, and it has been demonstrated that oxidative stress (OS) plays an important role in the pathogenesis of ICH. Previous studies have shown that OS is a therapeutic target after ICH, and antioxidants have also achieved some benefits in the treatment of ICH. This review aimed to explore the promise of natural products therapy to target OS in ICH. We searched PubMed using the keywords "oxidative stress in intracerebral hemorrhage" and "natural products in intracerebral hemorrhage". Numerous animal and cell studies on ICH have demonstrated the potent antioxidant properties of natural products, including polyphenols and phenolic compounds, terpenoids, alkaloids, etc. In summary, natural products such as antioxidants offer the possibility of treatment of OS after ICH. However, researchers still have a long way to go to apply these natural products for the treatment of ICH more widely in the clinic.

Erythrocyte Membrane-Enveloped Salvianolic Acid B Nanoparticles Attenuate Cerebral Ischemia-Reperfusion Injury.

Purpose: Ischemic stroke is the second leading cause of death and the third leading cause of disability worldwide. Salvianolic acid B (SAB), a water-soluble phenolic acid derived from the traditional Chinese medicine Salvia miltiorrhiza, exerted protective effects on cerebral ischemia-reperfusion injury. However, the efficacy of SAB is seriously hindered by poor blood brain barrier (BBB) permeability and short biological half-life in plasma. Brain targeted biomimetic nanoparticle delivery systems offer much promise in overcoming these limitations. Methods: A brain targeted biomimetic nanomedicine (RR@SABNPs) was developed, which comprised of SAB loaded bovine serum albumin nanoparticles and functionalized red blood cell membrane (RBCM) with Arg-Gly-Asp (RGD). The characterization parameters, including particle size, zeta potential, morphology, Encapsulation Efficiency (EE), Drug Loading (DL), release behavior, stability, and biocompatibility, were investigated. Moreover, the middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model was used to assess the therapeutic efficacy of RR@SABNPs on ischemic stroke. Finally, the reactive oxygen species (ROS) levels and mitochondrial membrane potential (MMP) were detected by DHE and JC­1 staining in oxygen-glucose deprivation/reperfusion (OGD/R) and H2O2 injured PC12 cells. Results: RR@SABNPs exhibited spheric morphology with core-shell structures and good stability and biocompatibility. Meanwhile, RR@SABNPs can significantly prolong SAB circulation time by overcoming the reticuloendothelial system (RES) and actively targeting ischemic BBB. Moreover, RR@SABNPs had comprehensive protective effects on MCAO/R model mice, manifested as a reduced infarct volume and improved neurological and sensorimotor functions, and significantly scavenged excess ROS and maintained MMP. Conclusion: The designed brain targeted biomimetic nanomedicine RR@SABNPs can significantly prolong the half-time of SAB, deliver SAB into the ischemic brain and exhibit good therapeutic effects on MCAO/R model mice.

Investigation on the potential targets of Astragaloside IV against intracerebral hemorrhage based on network pharmacology and experimental validation.

Intracerebral hemorrhage (ICH) is a life-threatening type of stroke that affects millions of individuals worldwide. Astragaloside IV (AS-IV), the main bioactive ingredient in Radix Astragali, has been linked to a variety of pharmacologic actions, including stroke. However, the effects and potential mechanisms of AS-IV on hematoma absorption after ICH are still unknown. The study aims to identify potential targets and regulation mechanisms of AS-IV on hematoma absorption after ICH. Network pharmacology, molecular docking, pharmacodynamic study, and western blot were used in this study to explore the potential mechanisms. The results showed that AS-IV could improve the hematoma absorption and neurological outcomes in collagenase VII induced rat ICH models. Molecular docking results had shown that PI3K and AKT were the potential targets of AS-IV against ICH. The experimental validation showed that AS-IV could reduce phosphorylation expression of PI3K and AKT, thereby inhibiting the NF-κB and increasing CD36 expression. This study demonstrated that AS-IV could play a critical role on hematoma absorption after ICH by regulating the PI3K/AKT signaling pathway and promoting CD36 phagocytosis, which provided a new thought for the drug development of ICH.

Diosgenin Ameliorates Non-alcoholic Fatty Liver Disease by Modulating the Gut Microbiota and Related Lipid/Amino Acid Metabolism in High Fat Diet-Fed Rats.

Non-alcoholic fatty liver disease (NAFLD) is a metabolic disease closely associated with dietary habits. Diosgenin is abundant in yam, a common food and traditional Chinese medicine. The molecular mechanism of diosgenin on NAFLD has been preliminarily explored. However, the effect of diosgenin on metabolism and gut microbiota in NAFLD has not been reported. This study confirmed that diosgenin could suppress excessive weight gain, reduce serum levels of total cholesterol and triglycerides, and decrease liver fat accumulation in high-fat diet-induced NAFLD rats. Moreover, fecal metabolomics analysis suggested diosgenin improved abnormal lipid and amino acid metabolism. Bile acids, including lithocholic acid and ursodeoxycholic acid 3-sulfate that function as excretion, absorption, and transport of fats, were remarkably regulated by diosgenin. Aromatic amino acid and lysine metabolism was regulated by diosgenin as well. 16S rRNA gene sequencing analysis demonstrated that diosgenin restored gut microbiota disorder, especially Globicatella, Phascolarctobacterium, Pseudochrobactrum, and uncultured_bacterium_f_Prevotellaceae at the genus level. Additionally, these regulated bacterial genera showed significant correlations with lipid and amino acid metabolism-related biomarkers. This study further confirmed the significant effect of diosgenin on NAFLD, and provided a new perspective for the mechanism.

Network Pharmacological Study on Mechanism of the Therapeutic Effect of Modified Duhuo Jisheng Decoction in Osteoporosis.

Background: Modified Duhuo Jisheng Decoction (MDHJSD) is a traditional Chinese medicine prescription for the treatment of osteoporosis (OP), but its mechanism of action has not yet been clarified. This study aims to explore the mechanism of MDHJSD in OP through a combination of network pharmacology analysis and experimental verification. Methods: The active ingredients and corresponding targets of MDHJSD were acquired from the Traditional Chinese Medicine System Pharmacology (TCMSP) database. OP-related targets were acquired from databases, including Genecards, OMIM, Drugbank, CTD, and PGKB. The key compounds, core targets, major biological processes, and signaling pathways of MDHJSD that improve OP were identified by constructing and analysing the relevant networks. The binding affinities between key compounds and core targets were verified using AutoDock Vina software. A rat model of ovariectomized OP was used for the experimental verification. Results: A total of 100 chemical constituents, 277 targets, and 4734 OP-related targets of MDHJSD were obtained. Subsequently, five core components and eight core targets were identified in the analysis. Pathway enrichment analysis revealed that overlapping targets were significantly enriched in the tumour necrosis factor-alpha (TNF-α) signaling pathway, an inflammation signaling pathway, which contained six of the eight core targets, including TNF-α, interleukin 6 (IL-6), transcription factor AP-1, mitogen-activated protein kinase 3, RAC-alpha serine/threonine-protein kinase, and caspase-3 (CASP3). Molecular docking analysis revealed close binding of the six core targets of the TNF signaling pathway to the core components. The results of experimental study show that MDHJSD can protect bone loss, inhibit the inflammatory response, and downregulate the expression levels of TNF-α, IL-6, and CASP3 in ovariectomized rats. Conclusion: The mechanism of MDHJSD in the treatment of OP may be related to the regulation of the inflammatory response in the bone tissue.

Pathways of cadmium fluxes in the root of the hyperaccumulator Celosia argentea Linn.

In order to study the mechanism of cadmium (Cd) uptake by the roots of Celosia argentea Linn. (Amaranthaceae), the effects of various inhibitors, ion channel blockers, and hydroponic conditions on Cd2+ fluxes in the roots were characterized using non-invasive micro-test technology (NMT). The net Cd2+ flux (72.5 pmol∙cm-2∙s-1) in roots that had been pretreated with Mn was significantly higher than that in non-pretreated roots (58.1 pmol∙cm-2∙s-1), indicating that Mn pretreatment enhanced Cd uptake by the roots. This finding may be explained by the fact that the addition of Mn significantly increased the expression of the transporter gene and thus promoted Cd uptake and transport. In addition, Mn pretreatment resulted in an increase in root growth, which may in turn promote root vigor. The uncoupler 2,4-dinitrophenol (DNP) caused a significant reduction in net Cd2+ fluxes in the roots, by 70.5% and 41.4% when exposed to Mn and Cd stress, respectively. In contrast, a P-type ATPase inhibitor (Na3VO4) had only a small effect on net Cd2+ fluxes to the plant roots, indicating that ATP has a relatively minor role in Cd uptake by roots. La3+ (a Ca channel inhibitor) had a more significant inhibitory effect on net Cd2+ fluxes than did TEA (a K channel inhibitor). Therefore, Cd uptake by plant roots may occur mainly through Ca channels rather than K channels. In summary, uptake of Cd by the roots of C. argentea appears to occur via several types of ion channels, and Mn can promote Cd uptake.

The natural (poly)phenols as modulators of microglia polarization via TLR4/NF-κB pathway exert anti-inflammatory activity in ischemic stroke.

Increasing evidences suggest that inflammation plays a key role in the pathogenesis of stroke, a devastating disease second only to cardiac ischemia as a cause of death worldwide. Microglia are the first non-neuronal cells on the scene during the innate immune response to acute ischemic stroke. Microglia respond to acute brain injury by activating and developing classic M1-like (pro-inflammatory) or alternative M2-like (anti-inflammatory) phenotypes. M1 microglia produce pro-inflammatory cytokines to exacerbate neural death, astrocyte apoptosis, and blood brain barrier (BBB) disruption, while M2 microglia play the opposite role. NF-κB, a central regulator of the inflammatory response, was responsible for microglia M1 and M2 polarization. NF-κB p65 and p50 form a heterodimer to initiate a pro-inflammatory cytokine response, which enhances M1 activation and impair M2 response of microglia. TLR4, expressed on the surface of microglia, plays an important role in activating NF-κB, ultimately causing the M1 response of microglia. Therefore, modulation of microglial phenotypes via TLR4/NF-κB signaling pathway may be a promising therapeutic approach for ischemic stroke. Dietary (poly)phenols are present in various foods, which have shown promising protective effects on ischemic stroke. In vivo studies strongly suggest that many (poly)phenols have a pronounced impact on ischemic stroke, as demonstrated by lower neuroinflammation. Thus, this review focuses on the anti-inflammatory properties of dietary (poly)phenols and discusses their effects on the polarization of microglia through modulating TLR4/NF-κB signaling pathway in the ischemic stroke.

Genetic syndromes screening by facial recognition technology: VGG-16 screening model construction and evaluation.

BACKGROUND: Many genetic syndromes (GSs) have distinct facial dysmorphism, and facial gestalts can be used as a diagnostic tool for recognizing a syndrome. Facial recognition technology has advanced in recent years, and the screening of GSs by facial recognition technology has become feasible. This study constructed an automatic facial recognition model for the identification of children with GSs. RESULTS: A total of 456 frontal facial photos were collected from 228 children with GSs and 228 healthy children in Guangdong Provincial People's Hospital from Jun 2016 to Jan 2021. Only one frontal facial image was selected for each participant. The VGG-16 network (named after its proposal lab, Visual Geometry Group from Oxford University) was pretrained by transfer learning methods, and a facial recognition model based on the VGG-16 architecture was constructed. The performance of the VGG-16 model was evaluated by five-fold cross-validation. Comparison of VGG-16 model to five physicians were also performed. The VGG-16 model achieved the highest accuracy of 0.8860 ± 0.0211, specificity of 0.9124 ± 0.0308, recall of 0.8597 ± 0.0190, F1-score of 0.8829 ± 0.0215 and an area under the receiver operating characteristic curve of 0.9443 ± 0.0276 (95% confidence interval: 0.9210-0.9620) for GS screening, which was significantly higher than that achieved by human experts. CONCLUSIONS: This study highlighted the feasibility of facial recognition technology for GSs identification. The VGG-16 recognition model can play a prominent role in GSs screening in clinical practice.

Automated Facial Recognition for Noonan Syndrome Using Novel Deep Convolutional Neural Network With Additive Angular Margin Loss.

BACKGROUND: Noonan syndrome (NS), a genetically heterogeneous disorder, presents with hypertelorism, ptosis, dysplastic pulmonary valve stenosis, hypertrophic cardiomyopathy, and small stature. Early detection and assessment of NS are crucial to formulating an individualized treatment protocol. However, the diagnostic rate of pediatricians and pediatric cardiologists is limited. To overcome this challenge, we propose an automated facial recognition model to identify NS using a novel deep convolutional neural network (DCNN) with a loss function called additive angular margin loss (ArcFace). METHODS: The proposed automated facial recognition models were trained on dataset that included 127 NS patients, 163 healthy children, and 130 children with several other dysmorphic syndromes. The photo dataset contained only one frontal face image from each participant. A novel DCNN framework with ArcFace loss function (DCNN-Arcface model) was constructed. Two traditional machine learning models and a DCNN model with cross-entropy loss function (DCNN-CE model) were also constructed. Transfer learning and data augmentation were applied in the training process. The identification performance of facial recognition models was assessed by five-fold cross-validation. Comparison of the DCNN-Arcface model to two traditional machine learning models, the DCNN-CE model, and six physicians were performed. RESULTS: At distinguishing NS patients from healthy children, the DCNN-Arcface model achieved an accuracy of 0.9201 ± 0.0138 and an area under the receiver operator characteristic curve (AUC) of 0.9797 ± 0.0055. At distinguishing NS patients from children with several other genetic syndromes, it achieved an accuracy of 0.8171 ± 0.0074 and an AUC of 0.9274 ± 0.0062. In both cases, the DCNN-Arcface model outperformed the two traditional machine learning models, the DCNN-CE model, and six physicians. CONCLUSION: This study shows that the proposed DCNN-Arcface model is a promising way to screen NS patients and can improve the NS diagnosis rate.

Automatic Facial Recognition of Williams-Beuren Syndrome Based on Deep Convolutional Neural Networks.

Background: Williams-Beuren syndrome (WBS) is a rare genetic syndrome with a characteristic "elfin" facial gestalt. The "elfin" facial characteristics include a broad forehead, periorbital puffiness, flat nasal bridge, short upturned nose, wide mouth, thick lips, and pointed chin. Recently, deep convolutional neural networks (CNNs) have been successfully applied to facial recognition for diagnosing genetic syndromes. However, there is little research on WBS facial recognition using deep CNNs. Objective: The purpose of this study was to construct an automatic facial recognition model for WBS diagnosis based on deep CNNs. Methods: The study enrolled 104 WBS children, 91 cases with other genetic syndromes, and 145 healthy children. The photo dataset used only one frontal facial photo from each participant. Five face recognition frameworks for WBS were constructed by adopting the VGG-16, VGG-19, ResNet-18, ResNet-34, and MobileNet-V2 architectures, respectively. ImageNet transfer learning was used to avoid over-fitting. The classification performance of the facial recognition models was assessed by five-fold cross validation, and comparison with human experts was performed. Results: The five face recognition frameworks for WBS were constructed. The VGG-19 model achieved the best performance. The accuracy, precision, recall, F1 score, and area under curve (AUC) of the VGG-19 model were 92.7 ± 1.3%, 94.0 ± 5.6%, 81.7 ± 3.6%, 87.2 ± 2.0%, and 89.6 ± 1.3%, respectively. The highest accuracy, precision, recall, F1 score, and AUC of human experts were 82.1, 65.9, 85.6, 74.5, and 83.0%, respectively. The AUCs of each human expert were inferior to the AUCs of the VGG-16 (88.6 ± 3.5%), VGG-19 (89.6 ± 1.3%), ResNet-18 (83.6 ± 8.2%), and ResNet-34 (86.3 ± 4.9%) models. Conclusions: This study highlighted the possibility of using deep CNNs for diagnosing WBS in clinical practice. The facial recognition framework based on VGG-19 could play a prominent role in WBS diagnosis. Transfer learning technology can help to construct facial recognition models of genetic syndromes with small-scale datasets.

Dysregulated cytokine production by dendritic cells modulates B cell responses in the NZM2410 mouse model of lupus.

The breakdown in tolerance of autoreactive B cells in the lupus-prone NZM2410-derived B6.Sle1.Sle2.Sle3 (TC) mice results in the secretion of autoantibodies. TC dendritic cells (DCs) enhance B cell proliferation and antibody secretion in a cytokine-dependent manner. However, the specific cytokine milieu by which TC DCs activate B cells was not known. In this study, we compared TC and C57BL/6 (B6) control for the distribution of DC subsets and for their production of cytokines affecting B cell responses. We show that TC DCs enhanced B cell proliferation through the production of IL-6 and IFN-γ, while antibody secretion was only dependent on IL-6. Pre-disease TC mice showed an expanded PDCA1(+) cells prior to disease onset that was localized to the marginal zone and further expanded with age. The presence of PDCA1(+) cells in the marginal zone correlated with a Type I Interferon (IFN) signature in marginal zone B cells, and this response was higher in TC than B6 mice. In vivo administration of anti-chromatin immune complexes upregulated IL-6 and IFN-γ production by splenic DCs from TC but not B6 mice. The production of BAFF and APRIL was decreased upon TC DC stimulation both in vitro and in vivo, indicating that these B cell survival factors do not play a role in B cell modulation by TC DCs. Finally, TC B cells were defective at downregulating IL-6 expression in response to anti-inflammatory apoptotic cell exposure. Overall, these results show that the TC autoimmune genetic background induces the production of B cell-modulating inflammatory cytokines by DCs, which are regulated by the microenvironment as well as the interplay between DC.

Contributions of B cells to lupus pathogenesis.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies. This review summarizes first the results obtained in the mouse that have revealed how B cell tolerance is breached in SLE. We then review the B cell subsets, in addition to the autoAb producing cells, which contribute to SLE pathogenesis, focusing on marginal zone B cells, B-1 cells and regulatory B cells. Finally, we review the interactions between B cells and other immune cells that have been implicated in SLE, such as dendritic cells, macrophages, neutrophils and T cells.

The granulocyte colony stimulating factor pathway regulates autoantibody production in a murine induced model of systemic lupus erythematosus.

INTRODUCTION: An NZB-derived genetic locus (Sle2c2) that suppresses autoantibody production in a mouse model of induced systemic lupus erythematosus contains a polymorphism in the gene encoding the G-CSF receptor. This study was designed to test the hypothesis that the Sle2c2 suppression is associated with an impaired G-CSF receptor function that can be overcome by exogenous G-CSF. METHODS: Leukocytes from B6.Sle2c2 and B6 congenic mice, which carry a different allele of the G-CSF receptor, were compared for their responses to G-CSF. Autoantibody production was induced with the chronic graft-versus-host-disease (cGVHD) model by adoptive transfer of B6.bm12 splenocytes. Different treatment regimens varying the amount and frequency of G-CSF (Neulasta®) or carrier control were tested on cGVHD outcomes. Autoantibody production, immune cell activation, and reactive oxygen species (ROS) production were compared between the two strains with the various treatments. In addition, the effect of G-CSF treatment was examined on the production autoantibodies in the B6.Sle1.Sle2.Sle3 (B6.TC) spontaneous model of lupus. RESULTS: B6.Sle2c2 and B6 leukocytes responded differently to G-CSF. G-CSF binding by B6.Sle2c2 leukocytes was reduced as compared to B6, which was associated with a reduced expansion in response to in vivo G-CSF treatment. G-CSF in vivo treatment also failed to mobilize bone-marrow B6.Sle2c2 neutrophils as it did for B6 neutrophils. In contrast, the expression of G-CSF responsive genes indicated a higher G-CSF receptor signaling in B6.Sle2c2 cells. G-CSF treatment restored the ability of B6.Sle2c2 mice to produce autoantibodies in a dose-dependent manner upon cGVHD induction, which correlated with restored CD4+ T cells activation, as well as dendritic cell and granulocyte expansion. Steady-state ROS production was higher in B6.Sle2c2 than in B6 mice. cGVHD induction resulted in a larger increase in ROS production in B6 than in B6.Sle2c2 mice, and this difference was eliminated with G-CSF treatment. Finally, a low dose G-CSF treatment accelerated the production of anti-dsDNA IgG in young B6.TC mice. CONCLUSION: The different in vivo and in vitro responses of B6.Sle2c2 leukocytes are consistent with the mutation in the G-CSFR having functional consequences. The elimination of Sle2c2 suppression of autoantibody production by exogenous G-CSF indicates that Sle2c2 corresponds to a loss of function of G-CSF receptor. This result was corroborated by the increased anti-dsDNA IgG production in G-CSF-treated B6.TC mice, which also carry the Sle2c2 locus. Overall, these results suggest that the G-CSF pathway regulates the production of autoantibodies in murine models of lupus.

Animal models of molecular pathology systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organ systems. A hallmark of SLE is the production of antinuclear antibodies against nuclear antigens such as chromatin and DNA. High levels of autoAbs promote the formation of immune complexes which can lead to the development of glomerulonephritis and progress to end-stage renal failure. Although the exact etiology of SLE is unknown, it is thought to be multifactorial in nature. A combination of environmental, hormonal, and a predisposed genetic background lead to the development of this disorder. Here, we review the various mouse models that have been used to study SLE and discuss how their study has led to a better understanding of the genetic and cellular factors involved in the development of systemic autoimmunity and lupus-like clinical symptoms. We also review the mouse studies that have explored the molecular pathways that are altered in this disease and the investigation of their therapeutic potentials.

Murine models of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disorder. The study of diverse mouse models of lupus has provided clues to the etiology of SLE. Spontaneous mouse models of lupus have led to identification of numerous susceptibility loci from which several candidate genes have emerged. Meanwhile, induced models of lupus have provided insight into the role of environmental factors in lupus pathogenesis as well as provided a better understanding of cellular mechanisms involved in the onset and progression of disease. The SLE-like phenotypes present in these models have also served to screen numerous potential SLE therapies. Due to the complex nature of SLE, it is necessary to understand the effect specific targeted therapies have on immune homeostasis. Furthermore, knowledge gained from mouse models will provide novel therapy targets for the treatment of SLE.

Autoreactive marginal zone B cells enter the follicles and interact with CD4+ T cells in lupus-prone mice.

BACKGROUND: Marginal zone B cells have been implicated in the production of autoantibodies in murine models of lupus. It has been suggested that they contribute to lupus immunopathogenesis through their enhanced effector functions and their repertoire that is biased toward autoreactive specificities. In the B6.NZM2410.Sle.Sle2.Sle3 (B6.TC) model of lupus, the majority of marginal zone B cells are located outside the marginal zone and inside the follicles. Genetic alterations of this strain have shown a correlation between autoimmune pathogenesis and the presence of intrafollicular marginal zone B cells. This study was designed first to strengthen our original observations and to determine how the marginal zone B cells from the lupus-prone mice respond to stimulations and interact with T cells. RESULTS: The intrafollicular location of B6.TC MZB cells starts before disease manifestations and puts MZB cells in direct contact with CD4+ T cells. Two different autoreactive B cell receptor (BCR) transgenic models showed that the expression of the Sle susceptibility loci enhances the presence of MZB cells inside the follicles. In vitro, B6.TC MZB cells were better effectors than B6 MZB cells with enhanced proliferation and antibody (Ab) production, including anti-DNA Ab, in response to stimulation with TLR ligands, immune complexes or anti-CD40. Furthermore, B6.TC MZB and CD4+ T cells showed a reciprocally enhanced activation, which indicated that their contacts inside B6.TC follicles have functional consequences that suggest an amplification loop between these two cell types. CONCLUSIONS: These results showed that the NZM2410 susceptibility loci induce MZB cells to locate into the follicles, and that this breach of follicular exclusion occurs early in the development of the autoimmune pathogenesis. The enhanced responses to stimulation and increased effector functions of MZB cells from lupus-prone mice as compare to non-autoimmune MZB cells provide a mechanism by which the failure of MZB cell follicular exclusion contributes to the autoimmune process.