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BACKGROUND: Macrophages are the main inflammatory cells involved in kidney injury and play a significant role in the development of acute kidney injury (AKI) and progression of chronic kidney disease (CKD). Emodin is believed to stabilize macrophage homeostasis under pathological conditions. The objective of this study aimed to explore the underlying mechanisms and effects of Emodin on M1 macrophages. METHODS: Network pharmacology methods were used to predict target proteins associated with renal injury and identify the pathways affected by emodin. RAW264.7 macrophages were induced into M1 polarization using LPS and then treated with emodin at 20, 40, and 80 µM. The effects of emodin on cell viability, cytokines (IL-1ß, IL-6, TNF-α), M1 macrophage markers (F4/80 + CD86+), and the EGFR/MAPK pathway were evaluated. Additionally, we transfected RAW264.7 cells with an EGFR shRNA interference lentivirus to assess its effects on RAW264.7 cells function and MAPK pathway. After RAW264.7 cells were passaged to expanded culture and transfected with EGFR-interfering plasmid, macrophages were induced to polarize towards M1 with LPS and then treated with 80 µM emodin. CKD modeling was performed to test how emodin is regulated during CKD. RESULTS: There are 15 common targets between emodin and kidney injury, of which the EGFR/MAPK pathway is the pathway through which emodin affects macrophage function. Emodin significantly reduced the levels of IL-6, IL-1ß and TNF-α (p < 0.05) and the ratio of M1 macrophage surface markers F4/80 + CD86+ (p < 0.01) in the supernatant of RAW264.7 cells in a dose-dependent manner. Furthermore, the inhibitory effect of emodin on RAW264.7 cells was achieved by interfering with the EGFR/MAPK pathway. Moreover, emodin also affected the mRNA and protein expression of EGFR and Ras, leading to a decrease in the rate of M1 macrophages, thus inhibiting the pro-inflammatory effect of M1 macrophages. The addition of emodin reduced the rate of M1 macrophages in CKD and inhibited the further polarization of M1 macrophages, thus maintaining the pro-inflammatory and anti-inflammatory homeostasis in CKD, and these effects were achieved by emodin through the control of the EGRF/ERK pathway. CONCLUSION: Emodin attenuates M1 macrophage polarization and pro-inflammatory responses via the EGFR/MAPK signalling pathway. And the addition of emodin maintains pro- and anti-inflammatory homeostasis, which is important for maintaining organ function and tissue repair.
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Lesión Renal Aguda , Emodina , Receptores ErbB , Sistema de Señalización de MAP Quinasas , Activación de Macrófagos , Macrófagos , Insuficiencia Renal Crónica , Animales , Ratones , Emodina/farmacología , Receptores ErbB/metabolismo , Receptores ErbB/genética , Células RAW 264.7 , Insuficiencia Renal Crónica/metabolismo , Insuficiencia Renal Crónica/tratamiento farmacológico , Insuficiencia Renal Crónica/genética , Insuficiencia Renal Crónica/patología , Activación de Macrófagos/efectos de los fármacos , Lesión Renal Aguda/genética , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/tratamiento farmacológico , Lesión Renal Aguda/patología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Citocinas/metabolismo , Citocinas/genéticaRESUMEN
BACKGROUND: Membranous nephropathy (MN) is one of the cardinal causes of nephrotic syndrome in adults, but an adequate treatment regimen is lacking. PURPOSE: We assessed the effect of Moshen granule (MSG) on patients with MN and cationic bovine serum albumin (CBSA)-induced rats. We further identified the bioactive components of MSG and revealed the underlying molecular mechanism of its renoprotective effects. METHODS: We determined the effect of MSG on patients with MN and CBSA-induced rats and its components on podocyte injury in zymosan-activated serum (ZAS)-elicited podocytes and revealed their regulatory mechanism on the Wnt/ß-catenin/renin-angiotensin system (RAS) signalling axis. RESULTS: MSG treatment improved renal function and reduced proteinuria in MN patients and significantly reduced proteinuria and preserved the protein expression of podocin, nephrin, podocalyxin and synaptopodin in CBSA-induced MN rats. Mechanistically, MSG treatment significantly inhibited the protein expression of angiotensinogen, angiotensin converting enzyme and angiotensin II type 1 receptor, which was accompanied by inhibition of the protein expression of Wnt1 and ß-catenin and its downstream gene products, including Snail1, Twist, matrix metalloproteinase-7, plasminogen activator inhibitor-1 and fibroblast-specific protein 1, in CBSA-induced MN rats. We further identified 81 compounds, including astragaloside IV (AGS), calycosin, barleriside A and geniposidic acid, that preserve the podocyte-specific protein expression in ZAS-induced podocytes. Among these four compounds, AGS exhibited the strongest inhibitory effects on podocyte protein expression. AGS treatment significantly inhibited the protein expression of RAS components and Wnt1 and ß-catenin and its downstream gene products in ZAS-induced podocytes. In contrast, the inhibitory effect of AGS on podocyte-specific proteins, ß-catenin downstream gene products and RAS components was partially abolished in ZAS-induced podocytes treated with ICG-001 and ß-catenin siRNA. CONCLUSION: This study first demonstrates that AGS mitigates podocyte injury by inhibiting the activation of RAS signalling via the Wnt1/ß-catenin pathway by both pharmacological and genetic methods. Therefore, AGS might be considered a new ß-catenin inhibitor that inhibits the Wnt1/ß-catenin pathway to retard MN in patients.
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Glomerulonefritis Membranosa , Sistema Renina-Angiotensina , Ratas , Animales , beta Catenina/metabolismo , Proteinuria , Vía de Señalización WntRESUMEN
Background: In recent years, the role of gut microbiota and derived metabolites in renal disease has attracted more attention. It has been established that the gut microbiota is a potential target for medical interventions in renal disease including chronic kidney disease (CKD), acute kidney injury (AKI) and renal calculus. Emerging evidence has related dialysis treatment to the microbial composition and function of the intestines, and there are many reports related to HD, but few studies have been related to PD. Previous studies have found that PD patients have intestinal flora disturbances, so we speculate that intestinal flora and its metabolites may be the regulatory factors in long-term therapy of PD. And as far as we know, there have been no studies characterized the gut microbiota in PD patients of different dialysis vintages. Methods: It is a cross-sectional study based on clinical data and biological samples of 72 patients with CAPD, 13 patients with ESRD and 13 healthy volunteers. The intestinal microecological characteristics of CAPD patients were comprehensively evaluated by combining the intestinal microflora structure, enterotoxin and receptor (serum LPS and LBP), intestinal barrier function index (serum D-Lactate), intestinal uremic toxin (serum IS, PCS, TMAO), fecal SCFAs and other multi-dimensional and multi-omics studies. Furthermore, the changes of intestinal microecology in CAPD patients of different dialysis vintages (≥ 3 and < 12 months, ≥ 12 and < 24 months, ≥ 24 and < 60 months, ≥ 60 months) were further explored, and the correlations between intestinal microecology indicators and some clinical indicators were analyzed. Fecal and serum samples were collected from PD patients (PD group, n = 72), ESRD patients (ESRD group, n = 13) and healthy volunteers (Normal group, n = 13). Fecal samples were subjected to microbiome (16S rDNA) and SCFA (GC-MS) analyses. Serum samples were subjected to LPS, LBP, D-lactate, IS, PCS, and TMAO (ELISA) analyses. Results: The diversity and richness of intestinal flora in CAPD patients were lower than those in healthy people and ESRD patients, and the microflora structure was different. Anaerobes of Blautia and facultative anaerobes and aerobic bacteria with Bacilli and Lactobacillales those in Firmicutes are the main intestinal flora in CAPD patients. The abundance of Bacteroidaceae, Bacteroides, Faecalibacterium and other dominant bacteria in the intestinal tract of CAPD patients decreased. Proteobacteria, Enterobacteriaceae and Escherichia-Shigella increased their colonization (LDA > 4). In CAPD patients of different dialysis vintages, there was no significant change in the diversity and richness of microflora, and the microflora structure of PDC group was significantly different from that of PDD, which the abnormal expansion of enterobacter group was more prominent in PDC and the abundance of Bacteroides group was relatively higher in PDD. Intestinal barrier damage, intestinal uremic toxin accumulation and short-chain fatty acid reduction were observed in CAPD patients, such as the serum level of D-Lactate, PCS and TMAO were significantly higher than that in the Normal group (P < 0.05),and the fecal levels of BA and CA were significantly lower (P < 0.05). The intestinal microecological disorder of PDC group, while that of PDD group showed a better trend. Such as the PDC group had a significantly higher serum level of LPS, D-Lactate and TMAO (P < 0.01), and significantly lower serum level of LBP (P < 0.01), and lower fecal levels of AA and BA (P > 0.05) than the PDD group. Conclusion: The intestinal microecology and metabolic system of CAPD patients had changes compared with healthy people and ESRD non-dialysis patients, and there were differences in CAPD patients with different dialysis vintages. PD patients on dialysis for more than 60 months showed a better trend in the intestinal microecology than patients with 24â¼36 months, which suggested that the intestinal microecology of PD patients had a certain ability of self-regulation and remodeling under the management of standardized system and it is necessary to strengthen the monitoring of the intestinal status and the occurrence of related complications in PD patients on dialysis of 24â¼36 months of dialysis vintage. It is initially considered that the mechanism of intestinal microecology is a potential target for intervention in the diagnosis and treatment of CAPD and incorporating intestinal microecosystem monitoring into the long-term management of CAPD patients is a new strategy.
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Objective: To identify potential diagnostic markers of lupus nephritis (LN) based on bioinformatics and machine learning and to explore the significance of immune cell infiltration in this pathology. Methods: Seven LN gene expression datasets were downloaded from the GEO database, and the larger sample size was used as the training group to obtain differential genes (DEGs) between LN and healthy controls, and to perform gene function, disease ontology (DO), and gene set enrichment analyses (GSEA). Two machine learning algorithms, least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE), were applied to identify candidate biomarkers. The diagnostic value of LN diagnostic gene biomarkers was further evaluated in the area under the ROC curve observed in the validation dataset. CIBERSORT was used to analyze 22 immune cell fractions from LN patients and to analyze their correlation with diagnostic markers. Results: Thirty and twenty-one DEGs were screened in kidney tissue and peripheral blood, respectively. Both of which covered macrophages and interferons. The disease enrichment analysis of DEGs in kidney tissues showed that they were mainly involved in immune and renal diseases, and in peripheral blood it was mainly enriched in cardiovascular system, bone marrow, and oral cavity. The machine learning algorithm combined with external dataset validation revealed that C1QA(AUC = 0.741), C1QB(AUC = 0.758), MX1(AUC = 0.865), RORC(AUC = 0.911), CD177(AUC = 0.855), DEFA4(AUC= 0.843)and HERC5(AUC = 0.880) had high diagnostic value and could be used as diagnostic biomarkers of LN. Compared to controls, pathways such as cell adhesion molecule cam, and systemic lupus erythematosus were activated in kidney tissues; cell cycle, cytoplasmic DNA sensing pathways, NOD-like receptor signaling pathways, proteasome, and RIG-1-like receptors were activated in peripheral blood. Immune cell infiltration analysis showed that diagnostic markers in kidney tissue were associated with T cells CD8 and Dendritic cells resting, and in blood were associated with T cells CD4 memory resting, suggesting that CD4 T cells, CD8 T cells and dendritic cells are closely related to the development and progression of LN. Conclusion: C1QA, C1QB, MX1, RORC, CD177, DEFA4 and HERC5 could be used as new candidate molecular markers for LN. It may provide new insights into the diagnosis and molecular treatment of LN in the future.
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Lupus Eritematoso Sistémico , Nefritis Lúpica , Humanos , Nefritis Lúpica/diagnóstico , Nefritis Lúpica/genética , Transcriptoma , Biología Computacional , Aprendizaje AutomáticoRESUMEN
Fibrosis is a pathological manifestation of wound healing that replaces dead/damaged tissue with collagen-rich scar tissue to maintain homeostasis, and complications from fibrosis contribute to nearly half of all deaths in the industrialized world. Ageing is closely associated with a progressive decline in organ function, and the prevalence of tissue fibrosis dramatically increases with age. Despite the heavy clinical and economic burden of organ fibrosis as the population ages, to date, there is a paucity of therapeutic strategies that are specifically designed to slow fibrosis. Aryl hydrocarbon receptor (AhR) is an environment-sensing transcription factor that exacerbates aging phenotypes in different tissues that has been brought back into the spotlight again with economic development since AhR could interact with persistent organic pollutants derived from incomplete waste combustion. In addition, gut microbiota dysbiosis plays a pivotal role in the pathogenesis of numerous diseases, and microbiota-associated tryptophan metabolites are dedicated contributors to fibrogenesis by acting as AhR ligands. Therefore, a better understanding of the effects of tryptophan metabolites on fibrosis modulation through AhR may facilitate the exploitation of new therapeutic avenues for patients with organ fibrosis. In this review, we primarily focus on how tryptophan-derived metabolites are involved in renal fibrosis, idiopathic pulmonary fibrosis, hepatic fibrosis and cardiac fibrosis. Moreover, a series of ongoing clinical trials are highlighted.
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Background: Hirudin has been widely used in the treatment of antifibrosis. Previous studies have shown that hirudin can effectively improve the clinical remission rate of chronic kidney disease. However, the mechanism of its renal protection has not been systematically investigated. Methods: In this study, the reliability of UUO-induced renal interstitial fibrosis was evaluated by histopathological verification. High-throughput transcriptome sequencing was used to elucidate the molecular mechanism of hirudin, differentially expressed mRNAs were identified, and their functions were analyzed by GO analysis and GSEA. In addition, the RNA-seq results were validated by in vitro and vivo experiments. Results: We found 322 identical differential expressed genes (IDEs) in the UUO hirudin-treated group compared with the sham group. Functional enrichment analysis indicated that cellular amino acid metabolic processes were the most obvious enrichment pathways in biological processes. In terms of molecular functional enrichment analysis, IDEs were mainly enriched in coenzyme binding, pyridoxal phosphate binding and other pathways. In addition, microbody is the most obvious pathway for cellular components. A total of 115 signaling pathways were enriched, and AMPK, JAK-STAT, and PI3K-Akt signaling pathways were the important signaling pathways enriched. We found that PI3K, p-Akt, and mTOR expression were significantly reduced by hirudin treatment. In particular, our results showed that hirudin could induce a decrease in the expression of autophagy-related proteins such as P62, LC3, Beclin-1 in TGF-ß1-induced NRK-52E cells. Conclusion: Our results suggest that hirudin may protect the kidney by ameliorating renal autophagy impairment through modulating the PI3K/Akt pathway.
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BACKGROUND: Peritoneal dialysis (PD) is an acknowledged treatment for patients with irreversible kidney failure. The treatment usually causes peritoneal dialysis-related peritonitis (PDRP), a common complication of PD that can lead to inadequate dialysis, gastrointestinal dysfunction, and even death. Recent studies indicated that Fushen Granule (FSG), a Chinese herbal formula, improves the treatment of PD. However, the mechanism of how FSG plays its role in the improvement is still unclear. Gut microbiota has been closely related to the development of various diseases. We carried out a randomized controlled trial to assess whether FSG can modulate the gut microbiota during PDRP treatment. METHODS: Forty-two PDRP patients were recruited into the clinical trial, and they were randomly divided into control(CON), probiotics(PRO) or Fushen granule group(FSG). To check whether FSG improve the PD treatment, we assessed the clinical parameters, including albumin(ALB), hemoglobin(HGB), blood urea nitrogen(BUN) and creatinine(CR). Fecal samples were collected before hospitalization and discharge, and stored at -80°C within 1 hour. And we assessed the microbial population and function by applying the 16S rRNA gene sequencing and functional enrichment analysis. RESULTS: Compared to control group, ALB is improved in both probiotics and FSG groups, while HGB is increased but BUN and CR is reduced in FSG group. Sequencing of 16S rRNA genes revealed that FSG and PRO affected the composition of the microbial community. FSG significantly increased a abundant represented by Bacteroides, Megamonas and Rothia, which was significantly correlated with the improvements in carbohydrate and amino acid metabolism. CONCLUSIONS: This study demonstrates that FSG ameliorates the nutritional status and improves the quality of life by enriching beneficial bacteria associated with metabolism. These results indicate that FSG as alternative medicine is a promising treatment for patients with PDRP.
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Medicamentos Herbarios Chinos/farmacología , Microbioma Gastrointestinal/efectos de los fármacos , Diálisis Peritoneal/efectos adversos , Peritonitis/tratamiento farmacológico , Peritonitis/etiología , Anciano , Nitrógeno de la Urea Sanguínea , Heces/microbiología , Femenino , Microbioma Gastrointestinal/genética , Humanos , Masculino , Persona de Mediana Edad , Calidad de Vida , ARN Ribosómico 16S/análisis , Albúmina Sérica Humana/análisis , Resultado del TratamientoRESUMEN
PURPOSE: Fushen Granule (FSG) is a Chinese medicine prepared by doctors for treating patients with chronic renal failure, which is usually accompanied by gastrointestinal dysfunction. Here, we explore the protective effect of FSG on intestinal barrier injury in chronic renal failure through bioinformatic analysis and experimental verification. METHODS: In this study, information on the components and targets of FSG related to CRF is collected to construct and visualize protein-protein interaction networks and drug-compound-target networks using network pharmacological methods. DAVID is used to conduct gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Then, it is validated by in vitro experiments. In this study, the human intestinal epithelial (T84) cells are used and divided into four groups: control group, model group, FSG low-dose group, and FSG high-dose group. After the experiment, the activity of T84 cells is detected by a MTT assay, and the expressions of tight junction protein ZO-1, claudin-1, nuclear factor erythroid 2-related factor (Nrf2), heme oxygenase-1 (HO-1), malondialdehyde (MDA), and cyclooxygenase-2 (COX-2) are examined by immunofluorescence and/or western blotting. RESULTS: Eighty-six potential chronic renal failure-related targets are identified by FSG; among them, nine core genes are screened. Furthermore, GO enrichment analysis shows that the cancer-related signaling pathway, the PI3K-Akt signaling pathway, the HIF1 signaling pathway, and the TNF signaling pathway may play key roles in the treatment of CRF by FSG. The MTT method showed that FSG is not cytotoxic to uremic toxin-induced injured T84 cells. The results of immunofluorescence and WB indicate that compared with the control group, protein expressions level of ZO-1, claudin-1, and Nrf2 in T84 cells is decreased and protein expressions level of HO-1, MDA, and COX-2 is increased after urinary toxin treatment. Instead, compared with the model group, protein expressions level of ZO-1, claudin-1, and Nrf2 in T84 cells is increased and protein expressions level of HO-1, MDA, and COX-2 is decreased after FSG treatment. CONCLUSION: FSG had a protective effect on urinary toxin-induced intestinal epithelial barrier injury in chronic renal failure, and its mechanism may be related to the upregulation of Nrf2/HO-1 signal transduction and the inhibition of tissue oxidative stress and inflammatory responses. Screening CRF targets and identifying the corresponding FSG components by network pharmacological methods is a practical strategy to explain the mechanism of FSG in improving gastrointestinal dysfunction in CRF.
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For Chronic Kidney Disease (CKD), the study of microRNA as a biomarker has become an exciting area, so we carried out a meta-analysis to investigate the potential diagnostic values of miRNAs in CKD. We searched Pubmed, Cochrane Library, Embase, and Web of science databases to identify relevant publications published from the establishment of the database to April 30, 2021. We included a total of 26 articles containing 56 studies. There were 4,098 patients with CKD and 2,450 patients without CKD. We found that the overall sensitivity and specificity of miRNAs in CKD diagnosis were 0.86 (95% CI: 0.83-0.89) and 0.79 (95% CI: 0.75-0.83), respectively. In addition, we plotted the summary receiver operator characteristic (SROC) curve to assess diagnostic accuracy, with the area under the curve (AUC) of 0.90 (95% CI: 0.87-0.92). Subgroup analysis showed that sensitivity, specificity, and AUC of miRNAs in plasma and serum were 0.84, 0.78, 0.88; and 0.79, 0.76, 0.83, respectively, while miRNAs in urine were 0.89 for sensitivity, 0.82 for specificity, and 0.92 for AUC. Moreover, we found that the panel of microRNAs (miRNAs) could improve the pooled sensitivity (0.88, 0.81, and 0.91 for sensitivity, specificity, and AUC, respectively). We believe that miRNAs have great potential to become an effective diagnostic biomarker for CKD. Panels of miRNA have higher accuracy than single miRNAs. Additionally, miRNAs in both blood and urine have significant accuracy in the diagnosis of CKD; nevertheless, urine is superior.
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BACKGROUND: Considering the adverse reactions and side effects of immunosuppressive and cytotoxic drugs for the treatment of Primary Nephrotic Syndrome (PNS) and the extensive exploration of Chinese herbal injections (CHIs), systematic evaluation of the efficacy of different CHIs in the treatment of PNS is a key imperative. In this study, we performed a network meta-analysis to investigate the efficacy of CHIs in the treatment of PNS. METHODS: A systematic literature review including studies published from the establishment of each database to May 28, 2020, was conducted in PubMed, the Cochrane Library, Embase, Web of Science, the Chinese Biological Medicine Literature Service System (CBM), the China National Knowledge Infrastructure (CNKI) database, the Chinese Scientific Journal Database (VIP), and the Wanfang Database (WF).Two evaluators independently screened the literature, extracted data and the Cochrane Reviewer's Handbook 5.1 method was used to evaluate the quality of included studies. The differences in efficacy of different CHIs were compared and ranked using Stata 16.0 software. Surface under the cumulative ranking curve (SUCRA) probability values were applied to rank the examined treatments. Clustering analysis was performed to compare the effects of CHIs between two different outcomes. RESULTS: A total of 41 eligible randomized controlled trials involving 2879 patients and nine CHIs were included. Nine CHIs were Xiangdan injection (XDI), Huangqi injection (HQI), Shenkang injection (SKI), Danshen injection (DSI), Yinxingdamo injection (YXI), Dengzhanhuasu injection (DZI), Danhong injection (DHI), Shuxuetong injection (SXI), Chuanxiongqin injection (CXI). The results of the network meta-analysis showed that: with Western medical (WM) treatment as a co-intervention, in terms of improving the total clinical effectiveness and serum albumin level, DHI was the most likely to be the best choice for treatment (SUCRA = 82.2%); YXI had the highest probability of being the best option in terms of reducing 24-h urinary protein excretion (SUCRA = 97.8%); in cholesterol-lowering comparisons, the SUCRA value allows for the most likely to be the best treatment is DZI (SUCRA = 84.5%). SXI was the most effective CHIs in terms of lowering serum triglycerides (SUCRA = 85.6%), whereas on the reducing fibrinogen side, the efficacy of CXI was significant (SUCRA = 67.6%). The result cluster analysis indicated that YXI and DHI were the best interventions with respect to total clinical effectiveness, 24-h urinary protein excretion and serum albumin. CONCLUSIONS: CHIs were found to be superior to WM alone in the treatment of PNS and may be beneficial for patients with PNS. WM+YXI and WM+DHI had the potential to be the best CHI with respect to the total clinical effectiveness, 24-h urinary protein excretion and serum albumin. However, more well-designed randomized controlled trials are still warranted.
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Lentiviral Nefs recruit assembly polypeptide complexes and target sorting motifs in cellular receptors to induce their internalization. While Nef-mediated CD4 downmodulation is conserved, the ability to internalize CD3 was lost in HIV-1 and its precursors. Although both functions play key roles in lentiviral replication and pathogenicity, the underlying structural requirements are poorly defined. Here, we determine the structure of SIVmac239 Nef bound to the ExxxLM motif of another Nef molecule at 2.5 Å resolution. This provides a basis for a structural model, where a hydrophobic crevice in simian immunodeficiency virus (SIV) Nef targets a dileucine motif in CD4 and a tyrosine-based motif in CD3. Introducing key residues into this crevice of HIV-1 Nef enables CD3 binding but an additional N-terminal tyrosine motif is required for internalization. Our resolution of the CD4/Nef/AP2 complex and generation of HIV-1 Nefs capable of CD3 downregulation provide insights into sorting motif interactions and target discrimination of Nef.HIV and simian immunodeficiency virus (SIV) Nef proteins both stimulate the clathrin-mediated endocytosis of CD4 but differ in downmodulation of the immune receptor CD3. Here, the authors present the structure of SIV Nef bound to the ExxxLM motif of another Nef molecule, which allows them to propose a model how Nef recognizes these motifs in CD3 and CD4.
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Complejo CD3/metabolismo , Antígenos CD4/metabolismo , Regulación hacia Abajo , Endocitosis , Productos del Gen nef/metabolismo , Secuencias de Aminoácidos , Cristalografía por Rayos X , Productos del Gen nef/química , Células HEK293 , VIH-1/metabolismo , Humanos , Leucocitos Mononucleares/metabolismo , Modelos Moleculares , Proteínas Mutantes/metabolismo , Mutación/genética , Unión Proteica , Receptores de Superficie Celular/metabolismo , Virus de la Inmunodeficiencia de los Simios , Factor de Transcripción AP-2/metabolismoRESUMEN
NF-κB is essential for effective transcription of primate lentiviral genomes and also activates antiviral host genes. Here, we show that the early protein Nef of most primate lentiviruses enhances NF-κB activation. In contrast, the late protein Vpu of HIV-1 and its simian precursors inhibits activation of NF-κB, even in the presence of Nef. Although this effect of Vpu did not correlate with its ability to interact with ß-TrCP, it involved the stabilization of IκB and reduced nuclear translocation of p65. Interestingly, however, Vpu did not affect casein kinase II-mediated phosphorylation of p65. Lack of Vpu was associated with increased NF-κB activation and induction of interferon and interferon-stimulated genes (ISGs) in HIV-1-infected T cells. Thus, HIV-1 and its simian precursors employ Nef to boost NF-κB activation early during the viral life cycle to initiate proviral transcription, while Vpu is used to downmodulate NF-κB-dependent expression of ISGs at later stages.
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Lentivirus de los Primates/metabolismo , FN-kappa B/metabolismo , Proteínas Virales/metabolismo , Animales , Expresión Génica , VIH-1/genética , VIH-1/metabolismo , Quinasa I-kappa B/metabolismo , Proteínas I-kappa B/metabolismo , Inmunidad Innata/fisiología , Lentivirus de los Primates/genética , Proteínas Virales/genéticaRESUMEN
UNLABELLED: The role of the accessory viral Nef protein as a multifunctional manipulator of the host cell that is required for effective replication of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) in vivo is well established. It is unknown, however, whether Nef manipulates all or just specific subsets of CD4(+) T cells, which are the main targets of virus infection and differ substantially in their state of activation and importance for a functional immune system. Here, we analyzed the effect of Nef proteins differing in their T cell receptor (TCR)-CD3 downmodulation function in HIV-infected human lymphoid aggregate cultures and peripheral blood mononuclear cells. We found that Nef efficiently downmodulates TCR-CD3 in naive and memory CD4(+) T cells and protects the latter against apoptosis. In contrast, highly proliferative CD45RA(+) CD45RO(+) CD4(+) T cells were main producers of infectious virus but largely refractory to TCR-CD3 downmodulation. Such T cell subset-specific differences were also observed for Nef-mediated modulation of CD4 but not for enhancement of virion infectivity. Our results indicate that Nef predominantly modulates surface receptors on CD4(+) T cell subsets that are not already fully permissive for viral replication. As a consequence, Nef-mediated downmodulation of TCR-CD3, which distinguishes most primate lentiviruses from HIV type 1 (HIV-1) and its vpu-containing simian precursors, may promote a selective preservation of central memory CD4(+) T cells, which are critical for the maintenance of a functional immune system. IMPORTANCE: The Nef proteins of human and simian immunodeficiency viruses manipulate infected CD4(+) T cells in multiple ways to promote viral replication and immune evasion in vivo. Here, we show that some effects of Nef are subset specific. Downmodulation of CD4 and TCR-CD3 is highly effective in central memory CD4(+) T cells, and the latter Nef function protects this T cell subset against apoptosis. In contrast, highly activated/proliferating CD4(+) T cells are largely refractory to receptor downmodulation but are main producers of infectious HIV-1. Nef-mediated enhancement of virion infectivity, however, was observed in all T cell subsets examined. Our results provide new insights into how primate lentiviruses manipulate their target cells and suggest that the TCR-CD3 downmodulation function of Nef may promote a selective preservation of memory CD4(+) T cells, which are critical for immune function, but has little effect on activated/proliferating CD4(+) T cells, which are the main targets for viral replication.
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Linfocitos T CD4-Positivos/virología , VIH-1/inmunología , Subgrupos de Linfocitos T/virología , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/metabolismo , Animales , Apoptosis , Complejo CD3/análisis , Linfocitos T CD4-Positivos/inmunología , Supervivencia Celular , Humanos , Antígenos Comunes de Leucocito/análisis , Receptores de Antígenos de Linfocitos T/análisis , Subgrupos de Linfocitos T/inmunologíaRESUMEN
Simian immunodeficiency virus (SIVsmm) infection of sooty mangabeys (Cercocebus atys) is characterized by stable CD4(+) T cell counts despite high plasma levels of CCR5-tropic viruses. However, in rare instances, SIVsmm acquires CXCR4 coreceptor tropism and causes severe CD4(+) T cell depletion, albeit without clinical signs of immunodeficiency. Here, we show that CXCR4-tropic SIVsmm strains lost their ability to downmodulate TCR-CD3 by evolving unusual Nef mutations that initially reduced (I132V) and subsequently disrupted (I123L and L146F) interaction with the CD3 ζ chain. This coevolution of Env and Nef function suggests that CD3 downmodulation is advantageous for viral replication in activated CCR5(+) memory T cells, but not in resting naive CXCR4(+) T cells that have not yet undergone TCR-CD3-mediated stimulation. This may explain why HIV-1, which generally lacks the CD3 downmodulation function, commonly switches to CXCR4 usage, whereas this is extremely rare for SIV strains that have retained this Nef activity.
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Complejo CD3/inmunología , Productos del Gen env/inmunología , Productos del Gen nef/inmunología , Complejo Receptor-CD3 del Antígeno de Linfocito T/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Animales , Células Presentadoras de Antígenos/inmunología , Complejo CD3/biosíntesis , Linfocitos T CD4-Positivos/inmunología , Células Cultivadas , Cercocebus/virología , Productos del Gen env/genética , Productos del Gen nef/genética , Infecciones por VIH/genética , Infecciones por VIH/inmunología , VIH-1/genética , VIH-1/inmunología , VIH-2/genética , VIH-2/inmunología , Memoria Inmunológica , Activación de Linfocitos/inmunología , Recuento de Linfocitos , Datos de Secuencia Molecular , Estructura Terciaria de Proteína , Receptores CCR5/inmunología , Receptores CXCR4/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/genética , Virus de la Inmunodeficiencia de los Simios/genética , Virus de la Inmunodeficiencia de los Simios/inmunologíaRESUMEN
BACKGROUND: The presence of a vpx gene distinguishes HIV-2 from HIV-1, the main causative agent of AIDS. Vpx degrades the restriction factor SAMHD1 to boost HIV-2 infection of macrophages and dendritic cells and it has been suggested that the activation of antiviral innate immune responses after Vpx-dependent infection of myeloid cells may explain why most HIV-2-infected individuals efficiently control viral replication and become long-term survivors. However, the role of Vpx-mediated SAMHD1 antagonism in the virological and clinical outcome of HIV-2 infection remained to be investigated. RESULTS: Here, we analyzed the anti-SAMHD1 activity of vpx alleles derived from seven viremic and four long-term aviremic HIV-2-infected individuals. We found that effective Vpx-mediated SAMHD1 degradation and enhancement of myeloid cell infection was preserved in most HIV-2-infected individuals including all seven that failed to control the virus and developed AIDS. The only exception were vpx alleles from an aviremic individual that predicted a M68K change in a highly conserved nuclear localization signal which disrupted the ability of Vpx to counteract SAMHD1. We also found that HIV-2 is less effective than HIV-1 in inducing innate immune activation in dendritic cells. CONCLUSIONS: Effective immune control of viral replication in HIV-2-infected individuals is not associated with increased Vpx-mediated degradation of SAMHD1.
Asunto(s)
VIH-2/inmunología , VIH-2/fisiología , Interacciones Huésped-Patógeno , Proteínas de Unión al GTP Monoméricas/antagonistas & inhibidores , Proteínas de Unión al GTP Monoméricas/inmunología , Proteínas Reguladoras y Accesorias Virales/metabolismo , Replicación Viral , Secuencia de Aminoácidos , Línea Celular , Análisis por Conglomerados , Células Dendríticas/inmunología , Células Dendríticas/virología , Infecciones por VIH/virología , VIH-2/aislamiento & purificación , Humanos , Datos de Secuencia Molecular , Filogenia , Proteolisis , Proteína 1 que Contiene Dominios SAM y HD , Análisis de Secuencia de ADNRESUMEN
The role of the multifunctional accessory Nef protein in the immunopathogenesis of HIV-2 infection is currently poorly understood. Here, we performed comprehensive functional analyses of 50 nef genes from 21 viremic (plasma viral load, >500 copies/ml) and 16 nonviremic (<500) HIV-2-infected individuals. On average, nef alleles from both groups were equally active in modulating CD4, TCR-CD3, CD28, MHC-I, and Ii cell surface expression and in enhancing virion infectivity. Thus, many HIV-2-infected individuals efficiently control the virus in spite of efficient Nef function. However, the potency of nef alleles in downmodulating TCR-CD3 and CD28 to suppress the activation and apoptosis of T cells correlated with high numbers of CD4(+) T cells in viremic patients. No such correlations were observed in HIV-2-infected individuals with undetectable viral load. Further functional analyses showed that the Nef-mediated downmodulation of TCR-CD3 suppressed the induction of Fas, Fas-L, PD-1, and CTLA-4 cell surface expression as well as the secretion of gamma interferon (IFN-γ) by primary CD4(+) T cells. Moreover, we identified a single naturally occurring amino acid variation (I132T) in the core domain of HIV-2 Nef that selectively disrupts its ability to downmodulate TCR-CD3 and results in functional properties highly reminiscent of HIV-1 Nef proteins. Taken together, our data suggest that the efficient Nef-mediated downmodulation of TCR-CD3 and CD28 help viremic HIV-2-infected individuals to maintain normal CD4(+) T cell homeostasis by preventing T cell activation and by suppressing the induction of death receptors that may affect the functionality and survival of both virally infected and uninfected bystander cells.
Asunto(s)
Antígenos CD28/metabolismo , Recuento de Linfocito CD4 , Infecciones por VIH/inmunología , VIH-2/metabolismo , Complejo Receptor-CD3 del Antígeno de Linfocito T/metabolismo , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/metabolismo , Sustitución de Aminoácidos , Apoptosis/genética , Línea Celular , Regulación hacia Abajo/inmunología , Expresión Génica , Orden Génico , Infecciones por VIH/metabolismo , VIH-2/genética , VIH-2/inmunología , Humanos , Leucocitos Mononucleares/metabolismo , Leucocitos Mononucleares/virología , Activación de Linfocitos/genética , Modelos Moleculares , Datos de Secuencia Molecular , Filogenia , Unión Proteica/inmunología , Conformación Proteica , Provirus/genética , Complejo Receptor-CD3 del Antígeno de Linfocito T/química , Receptores de Superficie Celular/metabolismo , Receptores de Muerte Celular/metabolismo , Linfocitos T/inmunología , Viremia/inmunología , Viremia/metabolismo , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/química , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/genéticaRESUMEN
Intracellular persistence of Chlamydia trachomatis has been implicated in the development of chronic infection that can result in pelvic inflammatory disease and tubal sterility. By inhibition of host cell apoptosis, chlamydiae have evolved a strategy to maintain the intracellular environment for replication and persistence. Both antiapoptotic host cell-derived factors and the chlamydial protease-like activity factor (CPAF) are involved in Chlamydia-mediated apoptosis resistance. Here, we show that in HeLa cells infected with gamma interferon (IFN-γ)-induced persistent C. trachomatis serovar D, the expression of CPAF is downregulated, and proapoptotic protease substrates are not cleaved. Persistent infection protected HeLa cells from apoptosis when they were exposed to staurosporine. Small-interfering RNA-mediated inhibition of myeloid cell leukemia 1 (Mcl-1) protein upregulation sensitized persistently infected cells for apoptosis. The inhibitor of apoptosis protein 2 (IAP-2) seems not to be relevant in this context because IAP-2 protein was not induced in response to IFN-γ treatment. Although apoptosis was inhibited, persistent infection caused cell membrane disintegration, as measured by the increased release of cytokeratin 18 from HeLa cells. Moreover, persistently infected cells released significantly increased amounts of high mobility group box 1 (HMGB1) protein which represents a proinflammatory damage-associated pattern molecule. The data of this study suggest that cells infected with persistent C. trachomatis are protected from apoptosis independently of CPAF but may promote chronic inflammation through HMGB1 release.
Asunto(s)
Apoptosis , Chlamydia trachomatis/patogenicidad , Endopeptidasas/metabolismo , Células Epiteliales/microbiología , Proteína HMGB1/metabolismo , Factores de Virulencia/metabolismo , Membrana Celular/fisiología , Supervivencia Celular , Chlamydia trachomatis/enzimología , Perfilación de la Expresión Génica , Regulación Bacteriana de la Expresión Génica , Células HeLa , Humanos , Interferón gamma/inmunología , Queratina-18/metabolismo , Estaurosporina/toxicidadRESUMEN
As intracellular bacteria, chlamydiae block the apoptotic pathways of their host cells. However, the infection of epithelial cells causes the loss of cell membrane integrity and can result in nonapoptotic death. Normally, cells undergoing necrosis release high-mobility group box 1 protein (HMGB1) that acts as an important proinflammatory mediator. Here, we show that in Chlamydia trachomatis-infected HeLa cells HMGB1 is not translocated from the nucleus to the cytosol and not released from injured cells in increased amounts. At 48 h after infection, degradation of HMGB1 was observed. In infected cells, poly(ADP-ribose) polymerase 1 (PARP-1), a DNA repair enzyme that also regulates HMGB1 translocation, was found to be cleaved into fragments that correspond to a necrosis like pattern of PARP-1 degradation. Cell-free cleavage assays and immunoprecipitation using purified proteolytic fractions from infected cells demonstrated that the chlamydial-protease-like activity factor (CPAF) is responsible for the cleavage of both HMGB1 and PARP-1. Proteolytic cleavage of PARP-1 was accompanied by a significant decrease in the enzymatic activity in a time-dependent manner. The loss of PARP-1 function obviously affects the viability of Chlamydia-infected cells because silencing of PARP-1 in uninfected HeLa cells with specific small interfering RNA results in increased cell membrane permeability. Our findings suggest that the Chlamydia-specific protease CPAF interferes with necrotic cell death pathways. By the degradation of HMGB1 and PARP-1, the pathogen may have evolved a strategy to reduce the inflammatory response to membrane-damaged cells in vivo.