Exosomes derived from bladder epithelial cells infected with uropathogenic Escherichia coli increase the severity of urinary tract infections (UTIs) by impairing macrophage function.

Uropathogenic Escherichia coli (UPEC) is the primary causative agent of urinary tract infections (UTIs) in humans. Moreover, as one of the most common bacterial pathogens, UPEC imposes a substantial burden on healthcare systems worldwide. Epithelial cells and macrophages are two major components of the innate immune system, which play critical roles in defending the bladder against UPEC invasion. Yet, the routes of communication between these cells during UTI pathogenesis are still not fully understood. In the present study, we investigated the role of membrane-bound nanovesicles (exosomes) in the communication between bladder epithelial cells and macrophages during UPEC infection, using an array of techniques such as flow cytometry, miRNA profiling, RNA sequencing, and western blotting. Moreover, our in vitro findings were validated in a mouse model of UPEC-induced cystitis. We found that UPEC infection induced the bladder epithelial MB49 cell line to secrete large numbers of exosomes (MB49-U-Exo), which were efficiently absorbed by macrophages both in vivo and in vitro. Assimilation of MB49-U-Exo induced macrophages to produce proinflammatory cytokines, including tumor necrosis factor (TNF)α. Exposure of macrophages to MB49-U-Exo reduced their phagocytic activity (by downregulating the expression of phagocytosis-related genes) and increased their rate of apoptosis. Mechanistically, we showed that MB49-U-Exo were enriched in miR-18a-5p, which induced TNFα expression in macrophages by targeting PTEN and activating the MAPK/JNK signaling pathway. Moreover, administration of the exosome secretion inhibitor GW4869 or a TNFα-neutralizing antibody alleviated UPEC-mediated tissue damage in mice with UPEC-induced cystitis by reducing the bacterial burden of the bladder and dampening the associated inflammatory response. Collectively, these findings suggest that MB49-U-Exo regulate macrophage function in a way that exacerbates UPEC-mediated tissue impairment. Thus, targeting exosomal -release or TNFα signaling during UPEC infection may represent promising non-antibiotic strategies for treating UTIs.

Construction and validation of a risk assessment model for acute kidney injury in patients with acute pancreatitis in the intensive care unit.

BACKGROUND: To construct and validate a risk assessment model for acute kidney injury (AKI) in patients with acute pancreatitis (AP) in the intensive care unit (ICU). METHODS: A total of 963 patients diagnosed with acute pancreatitis (AP) from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database was included. These patients were randomly divided into training set (N = 674) and validation set (N = 289) at a ratio of 7:3. Clinical characteristics were utilized to establish a nomogram for the prediction of AKI during ICU stay. These variables were selected by the least absolute shrinkage and selection operation (LASSO) regression and included in multivariate logistic regression analysis. Variables with P-values less than 0.05 were included in the final model. A nomogram was constructed based on the final model. The predicted accuracy of the nomogram was assessed by calculating the receiver operating characteristic curve (ROC) and the area under the curve (AUC). Moreover, calibration curves and Hosmer-Lemeshow goodness-of-fit test (HL test) were performed to evaluate model performance. Decision curve analysis (DCA) evaluated the clinical net benefit of the model. RESULTS: A multivariable model that included 6 variables: weight, SOFA score, white blood cell count, albumin, chronic heart failure, and sepsis. The C-index of the nomogram was 0.82, and the area under the receiver operating characteristic curve (AUC) of the training set and validation set were 0.82 (95% confidence interval:0.79-0.86) and 0.76 (95% confidence interval: 0.70-0.82), respectively. Calibration plots showed good consistency between predicted and observed outcomes in both the training and validation sets. DCA confirmed the clinical value of the model and its good impact on actual decision-making. CONCLUSION: We identified risk factors associated with the development of AKI in patients with AP. A risk prediction model for AKI in ICU patients with AP was constructed, and improving the treatment strategy of relevant factors in the model can reduce the risk of AKI in AP patients.

[Development and validation of a prognostic model for patients with sepsis in intensive care unit].

OBJECTIVE: To analyze the risk factors related to the prognosis of patients with sepsis in intensive care unit (ICU), construct a nomogram model, and verify its predictive efficacy. METHODS: A retrospective cohort study was conducted using data from Medical Information Mart for Intensive Care-IV 0.4 [MIMIC-IV (version 2.0)]. The information of 6 500 patients with sepsis who meet the diagnostic criteria of Sepsis-3 were collected, including demography characteristics, complications, laboratory indicators within 24 hours after ICU admission, and final outcome. Using a simple random sampling method, the patients were divided into a training set and a validation set at a ratio of 7 : 3. The restricted cubic spline (RCS) was used to explore whether there was a linear relationship between each variable and the prognosis, and the nonlinear variables were truncated into categorical variables. All variables were screened by LASSO regression and included in multivariate Cox regression analysis to analyze the death risk factors in ICU patients with sepsis, and construct a nomograph. The consistency index, calibration curve and receiver operator characteristic curve (ROC curve) were used to evaluate the prediction efficiency of nomogram model. The decision curve analysis (DCA) was used to validate the clinical value of the model and its impact on actual decision-making. RESULTS: Among 6 500 patients with sepsis, 4 551 were in the training set and 1 949 were in the validation set. The 28-day, 90-day and 1-year mortality in the training set were 27.73% (1 262/4 551), 34.76% (1 582/4 551), and 42.98% (1 956/4 551), respectively, those in the validation set were 27.24% (531/1 949), 33.91% (661/1 949), and 42.23% (823/1 949), respectively. Both in training set and the validation set, compared with the final survival patients, the death patients were older, and had higher sequential organ failure assessment (SOFA) score and simplified acute physiology score II (SAPS II), more comorbidities, less urine output, and more use of vasoactive drugs, kidney replacement therapy, and mechanical ventilation. By RCS analysis, the variables with potential nonlinear correlation with the prognosis risk of septic patients were transformed into categorical variable. The variables screened by LASSO regression were enrolled in the multivariate Cox regression model. The results showed that age [hazard ratio (HR) = 1.021, 95% confidence interval (95%CI) was 1.018-1.024], SOFA score (HR = 1.020, 95%CI was 1.000-1.040), SAPS II score > 44 (HR = 1.480, 95%CI was 1.340-1.634), mean arterial pressure (MAP) ≤ 75 mmHg (1 mmHg ≈ 0.133 kPa; HR = 1.120, 95%CI was 1.026-1.222), respiratory rate (RR; HR = 1.044, 95%CI was 1.034-1.055), cerebrovascular disease (HR = 1.620, 95%CI was 1.443-1.818), malignant tumor (HR = 1.604, 95%CI was 1.447-1.778), severe liver disease (HR = 1.330, 95%CI was 1.157-1.530), use of vasoactive drugs within 24 hours (HR = 1.213, 95%CI was 1.101-1.336), arterial partial pressure of oxygen (PaO2; HR = 0.999, 95%CI was 0.998-1.000), blood lactic acid (Lac; HR = 1.066, 95%CI was 1.053-1.079), blood urea nitrogen (BUN) > 8.9 mmol/L (HR = 1.257, 95%CI was 1.144-1.381), total bilirubin (TBil; HR = 1.023, 95%CI was 1.015-1.031), and prothrombin time (PT) > 14.5 s (HR = 1.232, 95%CI was 1.127-1.347) were associated with the death of ICU patients with sepsis (all P < 0.05). Based on the above factors, a nomogram model was constructed, and the model validation results showed that the consistency index was 0.730. The calibration curve showed a good consistency between the predicted results of the nomogram model and observed results in the training and validation sets. ROC curve analysis showed that the area under the ROC curve (AUC) predicted by the nomogram model in the training set and the validation set for 28-day, 90-day and 1-year death risk was 0.771 (95%CI was 0.756-0.786) and 0.761 (95%CI was 0.738-0.784), 0.777 (95%CI was 0.763-0.791) and 0.765 (95%CI was 0.744-0.787), 0.677 (95%CI was 0.648-0.707) and 0.685 (95%CI was 0.641-0.728), respectively. DCA analysis showed that the nomogram model had significant net benefits in predicting 28-day, 90-day, and 1-year death risk, verifying the clinical value of the model and its good impact on actual decision-making. CONCLUSIONS: The death risk factors related to ICU patients with sepsis include age, SOFA score, SAPS II score > 44, MAP ≤ 75 mmHg, RR, cerebrovascular disease, malignant tumors, severe liver disease, use of vasoactive drugs within 24 hours, PaO2, Lac, BUN, TBil, PT > 14.5 s. The nomogram model constructed based on this can predict the death risk of ICU patients with sepsis.

MiR-3960 inhibits bladder cancer progression via targeting of DEXI.

PURPOSE: MicroRNAs (miRNAs) are dominant cargo in exosomes and act as master regulators of cell function, inhibiting mRNA translation and affecting gene silencing. Some aspects of tissue-specific miRNA transport in bladder cancer (BC) and its role in cancer progression are not fully understood. MATERIALS AND METHODS: A microarray was used to identify miRNAs in mouse bladder carcinoma cell line MB49 exosomes. Real-time reverse transcription polymerase chain reaction was used to examine the expression of miRNAs in BC and healthy donor serum. Western blotting and immunohistochemical staining were used to examine the expression of dexamethasone-induced protein (DEXI) in patients with BC. CRISPR-Cas 9 was used to knock out Dexi in MB49, and flow cytometry was performed to test cell proliferation ability and apoptosis under chemotherapy. Human BC organoid culture, miR-3960 transfection, and 293T-exosome-loaded miR-3960 delivery were used to analyze the effect of miR-3960 on BC progression. RESULTS: The results showed that miR-3960 levels in BC tissue were positively correlated with patient survival time. Dexi was a major target of miR-3960. Dexi knockout inhibited MB49 cell proliferation and promoted cisplatin- and gemcitabine-induced apoptosis. Transfection of miR-3960 mimic inhibited DEXI expression and organoid growth. In parallel, 293T-exosome-loaded miR-3960 delivery and Dexi knockout significantly inhibited subcutaneous growth of MB49 cells in vivo. CONCLUSION: Our results demonstrate the potential role of miR-3960-mediated inhibition of DEXI as a therapeutic strategy against BC.

Inhibition of the glycogen synthase kinase 3ß-hypoxia-inducible factor 1α pathway alleviates NLRP3-mediated pyroptosis induced by high glucose in renal tubular epithelial cells.

NEW FINDINGS: What is the central question of this study? Activation of the glycogen synthase kinase 3 ß (GSK-3ß)-hypoxia-inducible factor 1 α (HIF-1α) pathway results in stimulation of pyroptosis under high glucose, and exerts actions in a number renal diseases: does this pathway have a role in renal tubular epithelial cells? What is the main finding and its importance? Down-regulation of GSK-3ß can inhibit pyroptosis of renal tubular epithelial cells induced by high glucose and this may be related to down-regulation of HIF-1α. This role of the GSK-3ß-HIF-1α pathway has not previously been reported and identifies a potential new therapeutic target in diabetic nephropathy. ABSTRACT: Diabetic nephropathy (DN) is not only one of the main complications of diabetes, but also has a high incidence rate and a high mortality rate. Glycogen synthase kinase 3 ß (GSK-3ß) and hypoxia-inducible factor 1 α (HIF-1α) have been demonstrated to influence DN by regulating pyroptosis. This study aimed to investigate the effect of the GSK-3ß-HIF-1α pathway on pyroptosis of high-glucose (HG)-induced renal tubular cells. Mouse renal proximal tubular epithelial cells (TKPT cells) were induced by HG to simulate DN cell and we transfected TKPT cells with GSK-3ß knockdown lentivirus. Western blot analysis confirmed the transfection effects and detected the expression of GSK-3ß, HIF-1α, Nod-like receptor protein 3 (NLRP3), cleaved-caspase-1, pro-caspase-1, gasdermin D (GSDMD) and GSDMD-N. The expression of GSDMD-N and HIF-1α were also verified by immunofluorescence. The levels of interleukin (IL)-1ß and IL-18 were measured by enzyme linked immunosorbent assay. Flow cytometric analysis determined the apoptosis rate. Results showed that HIF-1α expression was increased in HG-induced TKPT cells, and GSK-3ß knockdown could decrease the levels of NLRP3, cleaved-caspase-1, GSDMD-N and HIF-1α, verified by immunofluorescence. Moreover, GSK-3ß knockdown suppressed the expression of IL-1ß and IL-18, and reduced the apoptosis rate. Lithium chloride (LiCl) interference could cause the same changes as GSK-3ß knockdown for HG-induced TKPT cells, and dimethyloxallyl glycine could reverse the effect of GSK-3ß-knockdown interference. Our studies definitively demonstrate that the GSK-3ß-HIF-1α signalling pathway mediates HG-stimulated pyroptosis in renal tubular epithelial cells and that down-regulation of GSK-3ß inhibited HG-induced pyroptosis by inhibiting the expression of HIF-1α. These findings suggest a new potential target for the treatment of DN.

eRNAs Identify Immune Microenvironment Patterns and Provide a Novel Prognostic Tool in Acute Myeloid Leukemia.

Background: Enhancer RNAs (eRNAs) play an essential role in tumorigenesis as non-coding RNAs transcribed from enhancer regions. However, the landscape of eRNAs in acute myeloid leukemia (AML) and the potential roles of eRNAs in the tumor microenvironment (TME) remain unclear. Method: Gene expression data collected from The Cancer Genome Atlas (TCGA) project were combined with Histone ChIP-seq so as to reveal the comprehensive landscape of eRNAs. Single-sample gene set enrichment analysis algorithm (ssGSEA) and ESTIMATE were employed to enumerate immune cell infiltration and tumor purity. Results: Most prognostic eRNAs were enriched in immune-related pathways. Two distinct immune microenvironment patterns, the immune-active subtype and the immune-resistant subtype, were identified in AML. We further developed an eRNA-derived score (E-score) that could quantify immune microenvironment patterns and predict the response to immune checkpoint inhibitor (ICI) treatment. Finally, we established a prognostic nomogram combining E-score and other clinical features, which showed great discriminative power in both the training set [Harrell's concordance index (C index): 0.714 (0.651-0.777), p < 0.0001] and validation set [C index: 0.684 (0.614-0.755), p < 0.0001]. Calibration of the nomogram was also validated independently. Conclusion: In this study, we systematically understood the roles of eRNAs in regulating TME diversity and complexity. Moreover, our E-score model provided the first predictive model for ICI treatment in AML.

Tumor-derived exosomes drive pre-metastatic niche formation in lung via modulating CCL1+ fibroblast and CCR8+ Treg cell interactions.

BACKGROUND: Since the lung is one of the most common sites for cancer metastasis, it could provide a suitable microenvironment for pre-metastatic niche (PMN) formation to facilitate tumor cell colonization. Regulatory T cells (Tregs) are an immunosuppressive cell type found ubiquitously in tumors and may play a crucial role in PNM formation. In this study, we investigated tumor-derived exosome (TDE)-induced Treg differentiation in the lung PMN as well as the underlying mechanisms. METHODS: TDEs were isolated from the Lewis lung carcinoma cell line (LLC-exo) and their effects on mouse pulmonary fibroblasts was investigated in vitro as well as on lung tumor formation and metastasis in a pre-injected mouse model. Immune cell populations in the lung were analyzed by flow cytometry. Expression of CCL1 and CCR8 was evaluated by immunofluorescence staining, qRT-PCR and Western blot analyses. Cytokine expression was measured using mouse cytokine arrays and ELISA. RESULTS: The number of CD4+ FoxP3+ Tregs was significantly increased in lungs in a LLC-exo pre-injected mouse model. Lung fibroblasts secreted increased amounts of CCL1 after co-culture with LLC-exo, which induced Treg differentiation by activating its specific receptor CCR8, ultimately contributing to the establishment of an immunologically tolerant PMN. Moreover, inhibiting the release of LLC-exo by GW4869, or blocking the CCL1-CCR8 axis using AZ084, suppressed Tregs differentiation and tumor metastasis in the lung. CONCLUSIONS: Collectively, our study provides a novel mechanism by which Tregs are activated to form an immunologically tolerant PMN and demonstrates a critical link among lung fibroblasts, Tregs and metastatic tumor cells.

Inhibiting collagen I production and tumor cell colonization in the lung via miR-29a-3p loading of exosome-/liposome-based nanovesicles.

The lung is one of the most common sites for cancer metastasis. Collagens in the lung provide a permissive microenvironment that supports the colonization and outgrowth of disseminated tumor cells. Therefore, down-regulating the production of collagens may contribute to the inhibition of lung metastasis. It has been suggested that miR-29 exhibits effective anti-fibrotic activity by negatively regulating the expression of collagens. Indeed, our clinical lung tumor data shows that miR-29a-3p expression negatively correlates with collagen I expression in lung tumors and positively correlates with patients' outcomes. However, suitable carriers need to be selected to deliver this therapeutic miRNA to the lungs. In this study, we found that the chemotherapy drug cisplatin facilitated miR-29a-3p accumulation in the exosomes of lung tumor cells, and this type of exosomes exhibited a specific lung-targeting effect and promising collagen down-regulation. To scale up the preparation and simplify the delivery system, we designed a lung-targeting liposomal nanovesicle (by adjusting the molar ratio of DOTAP/cholesterol-miRNAs to 4:1) to carry miR-29a-3p and mimic the exosomes. This liposomal nanovesicle delivery system significantly down-regulated collagen I secretion by lung fibroblasts in vivo, thus alleviating the establishment of a pro-metastatic environment for circulating lung tumor cells.

Lysine Acetylation in the Proteome of Renal Tubular Epithelial Cells in Diabetic Nephropathy.

Diabetic nephropathy is considered one of the most common microvascular complications of diabetes and the pathophysiology involves multiple factors. Progressive diabetic nephropathy is believed to be related to the structure and function of the tubular epithelial cells in the kidney. However, the role of lysine acetylation in lesions of the renal tubular epithelial cells arising from hyperglycemia is poorly understood. Consequently, in this study, we cultured mouse renal tubular epithelial cells in vitro under high glucose conditions and analyzed the acetylation levels of proteins by liquid chromatography-high-resolution mass spectrometry. We identified 48 upregulated proteins and downregulated 86 proteins. In addition, we identified 113 sites with higher acetylation levels and 374 sites with lower acetylation levels. Subcellular localization analysis showed that the majority of the acetylated proteins were located in the mitochondria (43.17%), nucleus (28.57%) and cytoplasm (16.19%). Enrichment analysis indicated that these acetylated proteins are primarily associated with oxidative phosphorylation, the citrate cycle (TCA cycle), metabolic pathways and carbon metabolism. In addition, we used the MCODE plug-in and the cytoHubba plug-in in Cytoscape software to analyze the PPI network and displayed the first four most compact MOCDEs and the top 10 hub genes from the differentially expressed proteins between global and acetylated proteomes. Finally, we extracted 37 conserved motifs from 4915 acetylated peptides. Collectively, this comprehensive analysis of the proteome reveals novel insights into the role of lysine acetylation in tubular epithelial cells and may make a valuable contribution towards the identification of the pathological mechanisms of diabetic nephropathy.

Cancer derived exosomes induce macrophages immunosuppressive polarization to promote bladder cancer progression.

BACKGROUND: Exosomes mediated crosstalk between tumor cells and other stromal cells including tumor associated macrophages plays an essential role in reprogramming tumor microenvironment (TME) to facilitate tumor progression. However, the mechanism of tumor derived exosomes promotes bladder cancer progression have not been defined. METHODS: Exosomes were extracted from bladder cancer cells MB49 conditioned medium by ultracentrifugation. The effects of MB49-derived exosomes on macrophages polarization were analyzed by qPCR, flow cytometry, and Western blot. The immunosuppressive phenotype and function of MB49-derived exosomes stimulated macrophages were verified by tumor xenograft assays and T cell co-culture experiments. Exosomal miRNAs were analyzed by microarray to identify potential targets regulating macrophage polarization. RESULTS: MB49-derived exosomes could be ingested by macrophages, consequently promoting macrophages immunosuppressive polarization. Mechanically, the MB49-derived exosomes induced macrophage M2 polarization was mediated by down-regulation of PTEN and activation of AKT/STAT3/6 signaling. Moreover, hindrance of the generation or secretion of exosomes by GW4869 inhibited macrophages differentiation into immunosuppressive phenotype and function, thereby suppressed tumor growth in a mouse subcutaneous tumor model. CONCLUSION: Our study confirmed the contribution of bladder cancer derived exosomes on the establishment of immunosuppressive TME and provided a potential therapeutic target for bladder cancer treatment. Video Abstract.

Programmed PPAR-α downregulation induces inflammaging by suppressing fatty acid catabolism in monocytes.

Inflammaging is associated with an increased risk of chronic disease. Monocytes are the principal immune cells for the production of inflammatory cytokines and contribute to inflammaging in the elderly. However, the underlying mechanisms remain largely unknown. Here, we found that monocytes from aged individuals contained high levels of lipid droplets (LDs), and this increase was correlated with impaired fatty acid oxidation. Downregulated peroxisome proliferator-activated receptor (PPAR)-α may be responsible for the pro-inflammatory phenotype of monocytes in aged individuals, as it was positively correlated with LD accumulation and increasing TNF-α concentration. Interestingly, interventions that result in PPAR-α upregulation, such as fenofibrate treatment, TNF-α neutralization, or calorie restriction, reversed the effect of aging on monocytes. Thus the downregulation of PPAR-α and LD levels in monocytes represents a novel biomarker for inflammaging. Furthermore, PPAR-α activation in the elderly may also alleviate long-term inflammaging, preventing the development of life-limiting chronic diseases.

Corticosterone Enhances the AMPK-Mediated Immunosuppressive Phenotype of Testicular Macrophages During Uropathogenic Escherichia coli Induced Orchitis.

Testicular macrophages (TM) play a central role in maintaining testicular immune privilege and protecting spermatogenesis. Recent studies showed that their immunosuppressive properties are maintained by corticosterone in the testicular interstitial fluid, but the underlying molecular mechanisms are unknown. In this study, we treated mouse bone marrow-derived macrophages (BMDM) with corticosterone (50 ng/ml) and uncovered AMP-activated protein kinase (AMPK) activation as a critical event in M2 polarization at the phenotypic, metabolic, and cytokine production level. Primary TM exhibited remarkably similar metabolic and phenotypic features to corticosterone-treated BMDM, which were partially reversed by AMPK-inhibition. In a murine model of uropathogenic E. coli-elicited orchitis, intraperitoneal injection with corticosterone (0.1mg/day) increased the percentage of M2 TM in vivo, in a partially AMPK-dependent manner. This study integrates the influence of corticosterone on M2 macrophage metabolic pathways, phenotype, and function, and highlights a promising new avenue for the development of innovative therapeutics for orchitis patients.