CircC3P1 attenuated pro-inflammatory cytokine production and cell apoptosis in acute lung injury induced by sepsis through modulating miR-21

MiR-21-5p modulates LPS-induced acute injury in alveolar epithelial cells by targeting SLC16A10

Sepsis is a systemic inflammatory response syndrome resulting from the invasion of the human body by bacteria and other pathogenic microorganisms. One of its most prevalent complications is acute lung injury, which places a significant medical burden on numerous countries and regions due to its high morbidity and mortality rates. MicroRNA (miRNA) plays a critical role in the body's inflammatory response and immune regulation. Recent studies have focused on miR-21-5p in the context of acute lung injury, but its role appears to vary in different models of this condition. In the LPS-induced acute injury model of A549 cells, there is differential expression, but the specific mechanism remains unclear. Therefore, our aim is to investigate the changes in the expression of miR-21-5p and SLC16A10 in a type II alveolar epithelial cell injury model induced by LPS and explore the therapeutic effects of their targeted regulation. A549 cells were directly stimulated with 10 µg/ml of LPS to construct a model of LPS-induced cell injury. Cells were collected at different time points and the expression of interleukin 1 beta (IL-1β), tumor necrosis factor-α (TNF-α) and miR-21-5p were measured by RT-qPCR and western blot. Then miR-21-5p mimic transfection was used to up-regulate the expression of miR-21-5p in A549 cells and the expression of IL-1β and TNF-α in each group of cells was measured by RT-qPCR and western blot. The miRDB, TargetScan, miRWalk, Starbase, Tarbase and miR Tarbase databases were used to predict the miR-21-5p target genes and simultaneously, the DisGeNet database was used to search the sepsis-related gene groups. The intersection of the two groups was taken as the core gene. Luciferase reporter assay further verified SLC16A10 as the core gene with miR-21-5p. The expression of miR-21-5p and SLC16A10 were regulated by transfection or inhibitors in A549 cells with or without LPS stimulation. And then the expression of IL-1β and TNF-α in A549 cells was tested by RT-qPCR and western blot in different groups, clarifying the role of miR-21-5p-SLC16A10 axis in LPS-induced inflammatory injury in A549 cells. (1) IL-1β and TNF-α mRNA and protein expression significantly increased at 6, 12, and 24 h after LPS stimulation as well as the miR-21-5p expression compared with the control group (P < 0.05). (2) After overexpression of miR-21-5p in A549 cells, the expression of IL-1β and TNF-α was significantly reduced after LPS stimulation, suggesting that miR-21-5p has a protection against LPS-induced injury. (3) The core gene set, comprising 51 target genes of miR-21-5p intersecting with the 1448 sepsis-related genes, was identified. This set includes SLC16A10, TNPO1, STAT3, PIK3R1, and FASLG. Following a literature review, SLC16A10 was selected as the ultimate target gene. Dual luciferase assay results confirmed that SLC16A10 is indeed a target gene of miR-21-5p. (4) Knocking down SLC16A10 expression by siRNA significantly reduced the expression of IL-1β and TNF-α in A549 cells after LPS treatment (P < 0.05). (5) miR-21-5p inhibitor increased the expression levels of IL-1β and TNF-α in A549 cells after LPS stimulation (P < 0.05). In comparison to cells solely transfected with miR-21-5p inhibitor, co-transfection of miR-21-5p inhibitor and si-SLC6A10 significantly reduced the expression of IL-1β and TNF-α (P < 0.05). MiR-21-5p plays a protective role in LPS-induced acute inflammatory injury of A549 cells. By targeting SLC16A10, it effectively mitigates the inflammatory response in A549 cells induced by LPS. Furthermore, SLC16A10 holds promise as a potential target for the treatment of acute lung injury.

Unwinding circular RNA's role in inflammatory pulmonary diseases

Circular RNAs (circRNAs) have emerged as pivotal regulators of gene expression and cellular processes in various physiological and pathological conditions. In recent years, there has been a growing interest in investigating the role of circRNAs in inflammatory lung diseases, owing to their potential to modulate inflammation-associated pathways and contribute to disease pathogenesis. Inflammatory lung diseases, like asthma, chronic obstructive pulmonary disease (COPD), and COVID-19, pose significant global health challenges. The dysregulation of inflammatory responses demonstrates a pivotal function in advancing these diseases. CircRNAs have been identified as important players in regulating inflammation by functioning as miRNA sponges, engaging with RNA-binding proteins, and participating in intricate ceRNA networks. These interactions enable circRNAs to regulate the manifestation of key inflammatory genes and signaling pathways. Furthermore, emerging evidence suggests that specific circRNAs are differentially expressed in response to inflammatory stimuli and exhibit distinct patterns in various lung diseases. Their involvement in immune cell activation, cytokine production, and tissue remodeling processes underscores their possible capabilities as therapeutic targets and diagnostic biomarkers. Harnessing the knowledge of circRNA-mediated regulation in inflammatory lung diseases could lead to the development of innovative strategies for disease management and intervention. This review summarizes the current understanding of the role of circRNAs in inflammatory lung diseases, focusing on their regulatory mechanisms and functional implications.

MicroRNA-1258 suppresses oxidative stress and inflammation in septic acute lung injury through the Pknox1-regulated TGF-β1/SMAD3 cascade

AIM

The study was to clarify the mechanism of miR-1258 targeting Prep1 (pKnox1) to control Transforming Growth Factor β1 (TGF-β1)/SMAD3 pathway in septic Acute Lung Injury (ALI)-induced oxidative stress and inflammation.

METHODS

BEAS-2B cells and C57BL/6 mice were used to make in vitro and in vivo septic ALI models, respectively. miR-1258 expression was checked by RT-qPCR. After transfection in the in vitro experimental model, inflammation, oxidative stress, viability, and apoptosis were observed through ELISA, MTT, and flow cytometry.

RESULTS

In the in vivo model after miR-1258 overexpression treatment, inflammation, oxidative stress, and lung injury were further investigated. The targeting relationship between miR-1258 and Pknox1 was tested. Low miR-1258 was expressed in septic ALI patients, LPS-treated BEAS-2B cells, and mice. Upregulated miR-1258 prevented inflammation, oxidative stress, and apoptosis but enhanced the viability of LPS-treated BEAS-2B cells. The impact of upregulated miR-1258 on LPS-treated BEAS-2B cells was mitigated by inhibiting Pknox1 expression. MiR-1258 overexpression had the alleviating effects on inflammation, oxidative stress, and lung injury of LPS-injured mice through suppressing Pknox1 expression and TGF-β1/SMAD3 cascade activation.

CONCLUSIONS

The study concludes that miR-1258 suppresses oxidative stress and inflammation in septic ALI through the Pknox1-regulated TGF-β1/SMAD3 cascade.

Functional roles of circular RNAs in lung injury

Lung injury leads to respiratory dysfunction, low quality of life, and even life-threatening conditions. Circular RNAs (circRNAs) are endogenous RNAs produced by selective RNA splicing. Studies have reported their involvement in the progression of lung injury. Understanding the roles of circRNAs in lung injury may aid in elucidating the underlying mechanisms and provide new therapeutic targets. Thus, in this review, we aimed to summarize and discuss the characteristics and biological functions of circRNAs, and their roles in lung injury from existing research, to provide a theoretical basis for the use of circRNAs as a diagnostic and therapeutic target for lung injury.

Circular RNA circVAPA modulates macrophage pyroptosis in sepsis-induced acute lung injury through targeting miR-212-3p/Sirt1/Nrf2/NLRP3 axis

Sepsis-induced acute lung injury (ALI) is an inflammatory condition involving the pyroptosis of macrophages. This study investigated the role of circular RNA hsa_circ_0006990 (circVAPA) in regulating macrophage pyroptosis in ALI and the underlying mechanisms. The expression pattern of circVAPA was examined in the mouse model of ALI and in the LPS-treated RAW264.7 macrophage cell line. Lung tissue damage was evaluated by haematoxylin and eosin staining, immunohistochemistry and a myeloperoxidase activity assay. The molecular mechanisms were investigated by luciferase reporter assay, western blot, RT-qPCR and ELISA. circVAPA was down-regulated in the lung tissues of ALI mice and LPS-induced RAW264.7 cells. circVAPA over-expression alleviated lung tissue injury and dampened LPS-induced pyroptosis and Th17-associated inflammatory responses. miR-212-3p was identified as a target of circVAPA, and miR-212-3p negatively regulated the expression of Sirt1. Sirt1 knockdown largely abolished the effect of circVAPA over-expression on pyroptosis. CircVAPA/miR-212-3p/Sirt1 axis also regulates Nrf2 and NLRP3 expression upon LPS challenge. By targeting miR-212-3p, circVAPA over-expression negatively regulates the expression of Sirt1 and pyroptosis-related factors (Nrf2 and NLRP3), which alleviates the inflammatory damages in sepsis-induced ALI.

Circ_0114428 knockdown inhibits ROCK2 expression to assuage lipopolysaccharide-induced human pulmonary alveolar epithelial cell injury through miR-574-5p

BACKGROUND

Sepsis-induced acute lung injury (ALI) accounts for about 40% of ALI, accompanied by alveolar epithelial injury. The study aimed to reveal the role of circular RNA_0114428 (circ_0114428) in sepsis-induced ALI.

METHODS

Human pulmonary alveolar epithelial cells (HPAEpiCs) were treated with lipopolysaccharide (LPS) to mimic a sepsis-induced ALI cell model. RNA expression of circ_0114428, miR-574-5p and Rho-associated coiled-coil containing protein kinase 2 (ROCK2) was detected by qRT-PCR. Protein expression was checked by Western blotting. Cell viability, proliferation and apoptosis were investigated by cell counting kit-8, 5-Ethynyl-29-deoxyuridine (EdU) and flow cytometry analysis, respectively. The levels of pro-inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). Oxidative stress was analyzed by lipid peroxidation Malondialdehyde (MDA) and Superoxide Dismutase (SOD) activity detection assays. The interplay among circ_0114428, miR-574-5p and ROCK2 was identified by dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation assays.

RESULTS

Circ_0114428 and ROCK2 expression were significantly increased, but miR-574-5p was decreased in blood samples from sepsis patients and LPS-stimulated HPAEpiCs. LPS treatment led to decreased cell viability and proliferation and increased cell apoptosis, inflammation and oxidative stress; however, these effects were relieved after circ_0114428 knockdown. Besides, circ_0114428 acted as a miR-574-5p sponge and regulated LPS-treated HPAEpiC disorders through miR-574-5p. Meanwhile, ROCK2 was identified as a miR-574-5p target, and its silencing protected against LPS-induced cell injury. Importantly, circ_0114428 knockdown inhibited ROCK2 production by interacting with miR-574-5p.

CONCLUSION

Circ_0114428 knockdown protected against LPS-induced HPAEpiC injury through miR-574-5p/ROCK2 axis, providing a novel therapeutic target in sepsis-induced ALI.

CircUBR1 knockdown relieves ventilator-induced lung injury through regulating miR-20a-5p/GGPPS1 pathway

OBJECTIVE

To assess the influences and underlying mechanism of circular RNA UBR1 (circUBR1) in ventilator-induced lung injury (VILI).

METHODS

In mice and mouse alveolar epithelial cells, VILI model was established. CircUBR1 and miR-20a-5p expression was assessed via quantitative real time polymerase chain reaction. Western blot and immunohistochemistry were applied to assess geranylgeranyl diphosphate synthase 1 (GGPPS1) protein expression. In lung tissues, the histopathological changes were utilized using hematoxylin and eosin staining. Cell counting kit-8 assay and flow cytometer were applied to detect cell proliferation and apoptosis. The levels of inflammatory cytokines [interleukin (IL)-1β, IL-18, IL-6, and tumor necrosis factor (TNF)-α] were measured by western blot and enzyme-linked immunosorbent assay.

RESULTS

In lung tissues of VILI mice, circUBR1 and GGPPS1 expression were upregulated, while miR-20a-5p expression was downregulated. In vivo, circUBR1 knockdown alleviated lung injury, inhibited cell apoptosis, and decreased the levels of inflammatory cytokines. In cells treated with cyclic stretch (CS), circUBR1 knockdown promoted cell viability, inhibited cell apoptosis, and reduced inflammatory cytokines. CircUBR1 could sponge miR-20a-5p, and GGPPS1 was the target gene of miR-20a-5p. In addition, in cells treated with CS, downregulation of miR-20a-5p or the overexpression of GGPPS1 reversed the promotive effect of circUBR1 knockdown on cell viability and the inhibitive effect of circUBR1 knockdown on cell apoptosis and inflammation production.

CONCLUSIONS

In VILI, knockdown of circUBR1 attenuated lung injury and inflammation via regulating the miR-20a-5p/GGPPS1 pathway. Our study may provide a potential therapeutic target for treatment of VILI.

CIRC_0002131 CONTRIBUTES TO LPS-INDUCED APOPTOSIS, INFLAMMATION, AND OXIDATIVE INJURY IN HK-2 CELLS VIA INHIBITING THE BINDING BETWEEN MIR-942-5P AND OXSR1

ABSTRACT

Background: Circular RNAs are implicated in the progression of sepsis-associated acute kidney injury (AKI). Circ_0002131 was shown to aggravate cell inflammation and oxidative stress in sepsis-induced AKI. The aim of this study was to investigate the role and underlying mechanism of circ_0002131 in sepsis-induced AKI. Methods: Cell counting Ki-8 assay was used for cell viability detection. Cell apoptosis was measured using flow cytometry. Circ_0002131, microRNA-942-5p (miR-942-5p), and oxidative stress responsive 1 (OXSR1) level analysis was performed through reverse transcription-quantitative polymerase chain reaction assay. The protein levels were examined by western blot. Inflammatory factors were determined using enzyme-linked immunosorbent assay. Oxidative injury was assessed via commercial kits. Target relation was analyzed by dual-luciferase reporter assay and RNA immunoprecipitation assay. Results: HK-2 cell viability was suppressed and apoptosis was enhanced by LPS. Circ_0002131 was highly expressed in LPS-treated HK-2 cells and sepsis-induced AKI patients. LPS-induced apoptosis, inflammation, and oxidative injury of HK-2 cells were attenuated after silence of circ_0002131. Then, miR-942-5p was identified as a target for circ_0002131, and the regulation of circ_0002131 in LPS-induced cell injury was ascribed to reduce miR-942-5p level. In addition, circ_0002131 targeted miR-942-5p to elevate OXSR1 expression. MiR-942-5p prevented LPS-evoked HK-2 cell injury via targeting OXSR1. Conclusion : All results demonstrated that circ_0002131 promoted LPS-mediated HK-2 cell injury via miR-942-5p-mediated upregulation of OXSR1, suggesting that the circ_0002131/miR-942-5p/OXSR1 axis was related to sepsis-induced AKI progression.

INTERFERING HSA_CIRC_0001226 MITIGATES LPS-INDUCED BEAS-2B CELL INJURY BY REGULATING MIR-940/TGFBR2 PATHWAY

ABSTRACT

Background: Sepsis-associated acute lung injury (SA-ALI) is a serious threat to human health. A growing body of evidence suggested that circular RNAs may be involved in ALI progression. The aim of this study was to investigate the effect and mechanism of circ_0001226 on lipopolysaccharide (LPS)-induced BEAS-2B cells. Methods: BEAS-2B cells were stimulated with LPS to establish a SA-ALI cell model. The expression of circ_0001226, miR-940, and transforming growth factor beta receptor II (TGFBR2) were monitored by quantitative real-time polymerase chain reaction. Cell proliferation and apoptosis were evaluated by the Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine assay, and flow cytometry. The levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α were calculated by enzyme-linked immunosorbent assay. Western blot was implemented to test the protein levels of PCNA, Bax, and TGFBR2. Dual-luciferase reporter assay and RNA pull-down assay were adopted to investigate the interaction between circ_0001226 and miR-940, as well as TGFBR2 and miR-940. Results: The levels of circ_0001226 and TGFBR2 were elevated, and miR-940 was decreased in SA-ALI serum specimens and LPS-evoked BEAS-2B cells. Besides that, circ_0001226 interference contributed to cell proliferation and restrained apoptosis and inflammation in LPS-induced BEAS-2B cells. Mechanically, circ_0001226 worked as a molecular sponge of miR-940 to regulate TGFBR2 expression. Conclusion: Circ_0001226 deficiency weakened LPS-mediated proliferation inhibition and inflammatory processes in BEAS-2B cells by binding miR-940 and regulating TGFBR2.

Circ_0001714 knockdown alleviates lipopolysaccharide-induced apoptosis and inflammation in renal tubular epithelial cells via miR-129-5p/TRAF6 axis in septic acute kidney injury

BACKGROUND

Circular RNAs (circRNAs) have been shown to play roles in regulating sepsis. Sepsis is a major cause of acute kidney injury (AKI). Herein, we aimed to investigate the role and mechanism of circ_0001714 in the progression of sepsis-induced AKI.

METHODS

Human HK-2 cells were exposed to lipopolysaccharide (LPS) for functional experiments. Quantitative real-time polymerase chain reaction and western blotting were used for expression analysis. Functional experiments were performed by using MTT assay, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). The binding between miR-129-5p and circ_0001714 or TRAF6 (TNF receptor associated factor 6) was validated using dual-luciferase reporter assay.

RESULTS

Circ_0001714 expression was higher in sepsis-AKI patients. HK-2 cells were exposed to LPS to imitate the injury of renal tubular epithelial cells during sepsis-AKI. LPS dose-dependently up-regulated circ_0001714, moreover, circ_0001714 silencing reversed LPS-evoked apoptosis and inflammation in HK-2 cells. Mechanistically, circ_0001714 sequestered miR-129-5p to up-regulate TRAF6 expression, implying the circ_0001714/miR-129-5p/TRAF6 feedback loop. MiR-129-5p was decreased, while TRAF6 was increased in sepsis-AKI patients and LPS-stimulated HK-2 cells. MiR-129-5p re-expression or TRAF6 silencing protected against LPS-induced HK-2 cell apoptosis and inflammation. Additionally, a series of rescue experiments showed that miR-129-5p inhibition reversed the inhibitory action of circ_0001714 knockdown on LPS-induced HK-2 cell injury. Furthermore, TRAF6 overexpression also attenuated the protective effects of miR-129-5p on HK-2 cells under LPS treatment.

CONCLUSION

Circ_0001714 silencing might alleviate LPS-induced apoptosis and inflammation via targeting miR-129-5p/TRAF6 axis in HK-2 cells.

CIRCTDRD9 CONTRIBUTES TO SEPSIS-INDUCED ACUTE LUNG INJURY BY ENHANCING THE EXPRESSION OF RAB10 VIA DIRECTLY BINDING TO MIR-223-3P

ABSTRACT

Background: The dysregulation of circular RNAs (circRNAs) is involved in various human diseases, including sepsis-induced acute lung injury (ALI). We aimed to investigate the role of circTDRD9 in the development of sepsis-induced ALI. Methods: Cell models of sepsis-induced ALI were established by treating A549 cells with LPS. The expression of circTDRD9, miR-223-3p, and RAB10 mRNA was measured by quantitative real-time PCR (qPCR). The levels of inflammatory factors were measured by ELISA. Oxidative stress-related indicators were monitored by using commercial detection kits. The expression of fibrosis-related proteins was detected by Western blot assay. Cell proliferation was assessed by EdU assay. The predicted binding relationship between miR-223-3p and circTDRD9 or RAB10 was verified by dual-luciferase reporter assay, RIP assay or pull-down assay. Results: CircTDRD9 was highly expressed in LPS-treated A549 cells. CircTDRD9 downregulation prevented LPS-induced inflammation, oxidative stress, cell proliferation inhibition, and cell fibrosis in A549 cells, whereas these effects were reversed by the inhibition of miR-223-3p, a target of circTDRD9. In addition, RAB10 was verified as a target of miR-223-3p, and RAB10 overexpression recovered LPS-induced inflammation, oxidative stress, cell proliferation inhibition, and cell fibrosis in A549 cells that were ameliorated by miR-223-3p restoration. Importantly, circTDRD9 positively regulated RAB10 expression by binding to miR-223-3p. Conclusion: CircTDRD9 overexpression was closely associated with LPS-induced ALI. CircTDRD9 contributed to LPS-induced ALI partly by upregulating RAB10 via binding to miR-223-3p.

ERRα protects against sepsis-induced acute lung injury in rats

BACKGROUND

Sepsis-induced acute lung injury (ALI) is associated with poor survival rates. The identification of potential therapeutic targets for preventing sepsis-induced ALI has clinical importance. This study aims to investigate the role of estrogen-related receptor alpha (ERRα) in sepsis-induced ALI.

METHODS

Lipopolysaccharide (LPS) was used to simulate sepsis-induced ALI model in rat pulmonary microvascular endothelial cells (PMVECs). The effects of ERRα overexpression and knockdown on LPS-induced endothelial permeability, apoptosis and autophagy were determined by horseradish peroxidase permeability assay, TdT-mediated dUTP Nick End Labeling (TUNEL) assay, flow cytometry, immunofluorescence staining, RT-PCR and Western Blotting. The rat model with sepsis-induced ALI was established by cecal ligation and puncture in anesthetized rats to verify the results of in vitro experiments. Animals were randomly assigned to receive intraperitoneal injection of vehicle or ERRα agonist. Lung vascular permeability, pathological injury, apoptosis and autophagy were examined.

RESULTS

Overexpression of ERRα ameliorated LPS-induced endothelial hyperpermeability, degradation of adherens junctional molecules, upregulation of bax, cleaved caspase 3 and cleaved caspase 9 levels, downregulation of anti-apoptotic protein Bcl-2 level, and promoted the formation of autophagic flux, while the knockdown of ERRα exacerbated LPS-induced apoptosis and inhibited the activation of autophagy. Administration of ERRα agonist alleviated the pathological damage of lung tissue, increased the levels of tight junction proteins and adherens junction proteins, and decreased the expression of apoptosis-related proteins. Promoting the expression of ERRα significantly enhanced the process of autophagy and reduced CLP-induced ALI. Mechanistically, ERRα is essential to regulate the balance between autophagy and apoptosis to maintain the adherens junctional integrity.

CONCLUSION

ERRα protects against sepsis-induced ALI through ERRα-mediated apoptosis and autophagy. Activation of ERRα provides a new therapeutic opportunity to prevent sepsis-induced ALI.

A review on circular RNAs and bacterial infections

Bacterial infections and related diseases have been a major burden on social public health and economic stability around the world. However, the effective diagnostic methods and therapeutic approaches to treat bacterial infections are still limited. As a group of non-coding RNA, circular RNAs (circRNAs) that were expressed specifically in host cells and played a key regulatory role have the potential to be of diagnostic and therapeutic value. In this review, we systematically summarize the role of circRNAs in common bacterial infections and their potential roles as diagnostic markers and therapeutic targets.

Silencing circPalm2 inhibits sepsis-induced acute lung injury by sponging miR-376b-3p and targeting MAP3K1

The apoptosis and inflammation of pulmonary epithelial cells are important pathogenic factors of sepsis-induced acute lung injury (ALI). Upregulation of circPalm2 (circ_0001212) expression levels has been previously detected in the lung tissue of ALI rats. Herein, the biological significance and detailed mechanism of circPalm2 in ALI pathogenesis were investigated. In vivo models of sepsis-induced ALI were established by treating C57BL/6 mice with cecal ligation and puncture (CLP) surgery. Murine pulmonary epithelial cells (MLE-12 cells) were stimulated with lipopolysaccharide (LPS) to establish in vitro septic ALI models. MLE-12 cell viability and apoptosis were evaluated by CCK-8 assay and flow cytometry analysis, respectively. The pathological alterations of the lung tissue were analysed based on hematoxylin-eosin (H&E) staining. Cell apoptosis in the lung tissue samples was examined by TUNEL staining assay. LPS administration suppressed the viability and accelerated the inflammation and apoptotic behaviours of MLE-12 cells. CircPalm2 displayed high expression in LPS-stimulated MLE-12 cells and possessed circular characteristics. The silencing of circPalm2 impeded apoptosis and inflammation in LPS-stimulated MLE-12 cells. Mechanistically, circPalm2 bound with miR-376b-3p, which targeted MAP3K1. In rescue assays, MAP3K1 enhancement reversed the repressive effects of circPalm2 depletion on LPS-triggered inflammatory injury and MLE-12 cell apoptosis. Furthermore, the lung tissue collected from CLP model mice displayed low miR-376b-3p expression and high levels of circPalm2 and MAP3K1. CircPalm2 positively regulated MAP3K1 expression by downregulating miR-376b-3p in murine lung tissues. Importantly, circPalm2 knockdown attenuated CLP-induced inflammation, apoptosis, and pathological alterations in lung tissues collected from mice. Silenced circPalm2 inhibits LPS-induced pulmonary epithelial cell dysfunction and mitigates abnormalities in lung tissues collected from CLP-stimulated mice via the miR-376b-3p/MAP3K1 axis in septic ALI.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-022-00169-7.

CIRCKLHL2 KNOCKDOWN ALLEVIATES SEPSIS-INDUCED ACUTE LUNG INJURY BY REGULATING MIR-29B-3P MEDIATED ROCK1 EXPRESSION DOWN-REGULATION

ABSTRACT

Background: Acute lung injury (ALI) induced by sepsis is distinguished by an inflammatory progression. Herein, we investigated the action of circular RNA kelch like family member 2 (circKlhl2) in sepsis-induced ALI. Methods: The animal or cell model of sepsis ALI was established by LPS stimulation. The contents of circKlhl2, microRNA-29b-3p (miR-29b-3p), rho-associated coiled-coil containing protein kinase 1 (ROCK1), CyclinD1, B-cell lymphoma-2 (Bcl-2), and cleaved-caspase 3 (C-caspase-3) were detected by quantitative real-time polymerase chain reaction and western blot, respectively. Cell viability was assessed by cell counting kit 8 assay. Cell cycle and apoptosis were evaluated by flow cytometry. The abundances of proinflammatory cytokines were detected by enzyme-linked immunosorbent assay. Besides, the targeted relationship between miR-29b-3p and circKlhl2 or ROCK1 was verified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Results: Loss of circKlhl2 mitigated lung injury and proinflammatory cytokine expression in sepsis-ALI mice model and alleviated LPS-induced apoptosis and inflammatory response in microvascular endothelial cell (MPVECs) in vitro . The abundances of circKlhl2 and ROCK1 were boosted, while the miR-29b-3p level was diminished in the animal or cell model of sepsis-ALI. MiR-29b-3p inhibition abrogated circKlhl2 knockdown-mediated effects on MPVECs injury. Moreover, miR-29b-3p overexpression promoted cell proliferation and inhibited apoptosis and inflammation in LPS-treated MPVECs, while ROCK1 enhancement reversed these effects. Conclusion: CircKlhl2 expedited the sepsis-induced ALI by adjusting miR-29b-3p/ROCK1 axis.

circVMA21 combining with TAF15 stabilizes SOCS3 mRNA to relieve septic lung injury through regulating NF-κB activation

BACKGROUND

Lung injury is a severe complication of sepsis, which brings great threats and challenges to human health. CircVMA21 has exhibited powerful anti- inflammation capacity. However, its underlying molecule mechanism remains blurry.

METHODS

Lipopolysaccharide (LPS) was used to treat mice and WI-38 cells to establish models of lung injury caused by sepsis. Lung injury was evaluated using HE staining. Cell apoptosis was tested by TUNEL and flow cytometry. Levels of inflammatory cytokines were detected using ELISA assay. CircVMA21 and SOCS3 expression was measured using RT-qPCR. The ROS, MDA, SOD and GSH production were monitored by commercial kits. The protein expression was examined with western blot. The correlations among circVMA21, SOCS3 and TAF15 were confirmed using RIP and RNA-pull down.

RESULTS

The expression of circVMA21 and SOCS3 was downregulated in LPS-induced lung injury of mice and WI-38 cells. Overexpressing circVMA21 or SOCS3 assuaged LPS-induced cell injury through repressing the levels of inflammatory factors, oxidative stress and cell apoptosis. NF-κB signaling pathway was inactivated by circVMA21 or SOCS3 overexpression. circVMA21 enhanced the stabilization of SOCS3 mRNA via interplaying with TAF15. SOCS3 knockdown destroyed the beneficial impacts of circVMA21 overexpression on LPS-induced cell injury.

CONCLUSION

CircVMA21 suppressed LPS-induced the levels of inflammatory factors, oxidative stress and cell apoptosis and improved LPS-induced lung injury by mediating TAF15/SOCS3/NF-κB axis.

CircEXOC5 facilitates cell pyroptosis via epigenetic suppression of Nrf2 in septic acute lung injury

Acute lung injury (ALI) caused by sepsis is characterized by a destructive high inflammatory response in lungs, which is the ultimate cause of high mortality to patients diagnosed with sepsis. The objective of the present study is to explore the effect and related mechanisms of circEXOC5 on pyroptosis in septic ALI. Sepsis ALI mouse model was induced and established by CLP induction and sepsis MPVEC cell model by LPS. HE staining was used to detect lung tissue pathological changes. ELISA, flow cytometry, and Western blot were utilized to evaluate the release of inflammatory cytokines and cell pyroptosis, and RIP was applied to verify the binding relationship between EZH2 and circEXOC5 or Nrf2. Finally, the interaction between CircEXOC5 and EZH2, H3k27me3, and Nrf2 promoter regions was clarified using ChIP. CircEXOC5 levels were notably ascended in the lung tissues of septic ALI mice. And silencing circEXOC5 inhibited cell pyroptosis and the release of inflammatory cytokines in MPVEC stimulated by LPS. In addition, RIP and ChIP indicated that Nrf2 expression in MPVECs cells could be inhibited by circEXOC5 via recruiting EZH2. In addition, ML385 (a specific inhibitor of Nrf2) reversed the efficacy of Knockdown of circEXOC5 on the Inhibition of pyroptosis and inflammation of MPVEC cells stimulated by LPS. These results indicated that CircEXOC5 could promote cell pyroptosis through epigenetic inhibition of Nrf2 in septic ALI.

Aurantiamide Acetate Ameliorates Lung Inflammation in Lipopolysaccharide-Induced Acute Lung Injury in Mice

Purpose

Aurantiamide acetate (AA) is a dipeptide derivative with complex pharmacological activities and remarkable effects on preventing and treating various diseases. In the current study, we aimed to investigate whether AA can exert protective effects in a mouse model of ALI induced by LPS.

Materials and Methods

In this model, mice were given intranasal LPS for 3 days prior to receiving AA (2.5, 5, and 10 mg/kg) via oral gavage. An assessment of histopathological changes was performed by hematoxylin and eosin (HE). Proinflammatory cytokines were detected in bronchoalveolar lavage fluids (BALFs) by enzyme-linked immunosorbent assays (ELISAs). The effects of AA on protein expression of NF-κB and PI3K/AKT signaling pathways were determined by Western blot. In addition, lung wet/dry (W/D) weight ratio, myeloperoxidase (MPO) activity, cell counts, and protein content were also measured.

Results

According to results, AA pretreatment significantly reduced lung pathological changes, W/D ratio, MPO activity, and protein content. Additionally, AA resulted in a significant reduction in the number of total cells, neutrophils, and proinflammatory cytokines in the BALF after LPS stimulation. The subsequent study revealed that pretreatment with AA dose dependently suppressed LPS-induced activation of NF-κB as well as PI3K/AKT phosphorylation.

Conclusion

The results indicated that the AA had a protective effect on LPS-induced ALI in mice and could be a potential drug for ALI.

The circular RNA hsa_circ_0003091 regulates sepsis-induced lung injury by sponging the miR-149/Smad2 axis

Sepsis-induced acute lung injury (ALI) is a severe cause of death. Increasing evidence has identified circular RNAs (circRNAs) acting as critical regulators of human diseases. However, their expression pattern and underlying mechanisms in ALI remain unclear. Herein, we screened the circRNAs of ALI patients and constructed a lung injury murine model using lipopolysaccharides (LPS) induction. Functional analyses of targeted circRNA were performed in vivo and in vitro. Then, the downstream miRNA and mRNA of specific circRNAs were identified. Compared to healthy subjects, 35 circRNAs were upregulated and 9 circRNAs were downregulated in sepsis patients. The top 10 differentially expressed circRNAs were selected for validation and has_circ_0003091 was selected. The ALI mice presented significantly elevated has_circ_0003091 (mmu_circ_0015268). The functional analysis revealed that mmu_circ_0015268 contributed to the pulmonary injury, cell apoptosis, inflammatory responses, and endothelial activation in the ALI murine model. On the other hand, silencing mmu_circ_0015268 showed protective effects in LPS-treated mice and PMVECs. Furthermore, mmu_circ_0015268 sponged miR-149 to upregulate the expression of its target Smad2. In summary, we demonstrated that has_circ_0003091 might be a novel target for the management and treatment of sepsis-induced ALI.

Lipopolysaccharide-induced lung cell inflammation and apoptosis are enhanced by circ_0003420/miR-424-5p/TLR4 axis via inactivating the NF-κB signaling pathway

BACKGROUND

Circular RNAs (circRNAs) can regulate disease progression, including sepsis-induced acute lung injury (ALI). This research aimed at investigating the function of circ_0003420 in lipopolysaccharide (LPS)-treated lung cells, as well as the functional mechanism.

METHODS

Enzyme-linked immunosorbent assay was used for inflammation analysis. Cell viability and proliferation were examined using Cell Counting Kit-8 assay and EdU assay. Cell apoptosis was measured by flow cytometry. Western blot was used for protein detection. Reverse transcription-quantitative polymerase chain reaction assay was performed for quantification of circ_0003420, microRNA-424-5p (miR-424-5p) or toll-like receptor (TLR4). The interaction between miR-424-5p and circ_0003420 or TLR4 was conducted through dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay.

RESULTS

Lung cell inflammation and apoptosis were promoted, but cell viability and proliferation were inhibited by LPS. Silence of circ_0003420 attenuated the LPS-mediated lung cell injury. Circ_0003420 could interact with miR-424-5p. The protective function by knockdown of si-circ_0003420 was relieved by miR-424-5p inhibition in LPS-treated cells. TLR4 served as a downstream target of miR-424-5p. Overexpression of miR-424-5p repressed inflammatory and apoptotic damages in LPS-treated lung cells via downregulating TLR4. Circ_0003420 upregulated the TLR4 level by targeting miR-424-5p and circ_0003420 regulated the NF-κB signaling pathway through the miR-424-5p/TLR4 axis.

CONCLUSION

These results uncovered that circ_0003420 contributed to the LPS-induced lung cell injury via activating the miR-424-5p/TLR4-related NF-κB signaling pathway. Circ_0003420 might be a therapeutic target in sepsis-induced ALI.

Tranilast attenuates lipopolysaccharide‑induced lung injury via the CXCR4/JAK2/STAT3 signaling pathway

It has been reported that the expression of C-X-C motif chemokine receptor 4 (CXCR4) is increased in patients with lung injury, while CXCR4 downregulation can improve sepsis-induced lung injury. Previous studies have shown that tranilast can inhibit CXCR4 mRNA expression. Therefore, the present study aimed to investigate whether tranilast could protect against lipopolysaccharide (LPS)-induced lung injury via the CXCR4/Janus kinase 2 (JAK2)/STAT3 signaling pathway. A Cell Counting Kit-8 assay was performed to evaluate the effect of different concentrations of tranilast on the viability of LPS-induced BEAS-2B cells. The mRNA and protein expression levels of the inflammatory factors, TNFα, IL-1β, IL-6, cytochrome c oxidase subunit II and inducible nitric oxide synthase were detected using reverse transcription-quantitative PCR and western blot analysis, respectively. In addition, the cell apoptosis rate and the expression levels of apoptosis-related proteins were analyzed using a TUNEL staining assay and western blot analysis, respectively. The expression levels of the CXCR4/JAK2/STAT3 signaling pathway-related proteins were also determined using western blot analysis. Furthermore, the effects of tranilast on cell viability, inflammation and apoptosis were also evaluated in LPS-stimulated BEAS-2B cells following CXCR4 overexpression, which were pre-treated with tranilast. The results demonstrated that tranilast could alleviate LPS-induced cell viability, the secretion of inflammatory cytokines and cell apoptosis. In addition, cell treatment with tranilast inhibited the expression of CXCR4/JAK2/STAT3 signaling-related proteins in LPS-induced BEAS-2B cells. Following CXCR4 overexpression, the alleviating effect of tranilast on cell viability, inflammatory response and apoptosis was notably attenuated. Overall, the current study suggested that tranilast could attenuate LPS-induced lung injury via the CXCR4/JAK2/STAT3 signaling pathway, suggesting that tranilast could be considered as a promising agent for treating sepsis-induced acute lung injury.

Circular RNAs in the pathogenesis of sepsis and their clinical implications: A narrative review

Introduction: Sepsis is defined as a life-threatening complication that occurs when the body responds to an infection attacking the host. Sepsis rapidly progresses and patients deteriorate and develop septic shock, with multiple organ failure, if not promptly treated. Currently no effective therapy is available for sepsis; therefore, early diagnosis is crucial to decrease the high mortality rate. Genome-wide expression analyses of patients in critical conditions have confirmed that the expression levels of the majority of genes are changed, suggesting that the molecular basis of sepsis is at the gene level. This review aims to elucidate the role of circular (circ) RNAs in the pathogenesis of sepsis and sepsis-induced organ damage. In addition, the feasibility of using circRNAs as novel diagnostic biomarkers for sepsis is also discussed, as well as circRNA-based therapy. Method: This narrative review is based on a literature search using Medline database. Search terms used were “circular RNAs and sepsis”, “circRNAs and sepsis”, “non-coding RNAs and sepsis”, “ncRNAs and sepsis”, “circRNAs and septic pathogenesis”, “circRNAs and septic model”, “circRNAs and septic shock” and “circRNAs, biomarker, and sepsis”. Results: Numerous studies indicate that circRNAs might exert pivotal roles in regulating the immune system of the host against various pathogens, such as bacteria and viruses. Dysregulation of circRNA expression levels has been confirmed as an early event in sepsis and associated with the inflammatory response, immunosuppression and coagulation dysfunction. This impairment in regulation eventually leads to multiple organ dysfunctions, including of the kidneys, lungs and heart. Conclusion: By investigating the regulation of circRNAs in sepsis, new molecular targets for the diagnosis and intervention of sepsis can be identified. Such an understanding will be important for the development of therapeutic drugs. Keywords: Acute kidney injury, biomarker, circRNAs, inflammation, sepsis

Knockdown of circ_0001679 alleviates lipopolysaccharide-induced MLE-12 lung cell injury by regulating the miR-338-3p/ mitogen-activated protein kinase 1 axis

The upregulation of circ_0001679 was reported in lipopolysaccharide (LPS)-induced lung injury mouse model, but its functional roles and mechanisms in LPS-induced lung injury remain to be investigated. In this study, we aimed to explore the potential role of circ_0001679 in septic acute lung injury. We initially established an in vitro lung cell injury model using LPS-treated MLE-12 cells. siRNAs targeting circRNA_0001679 were employed to stably knock down circRNA_0001679, followed by functional assays to investigate the effect of circRNA_0001679 silencing. The levels of inflammatory cytokines such as IL-6, IL-β and TNF-α (Tumor necrosis factor-α) were detected by ELISA (Enzyme-linked immunosorbent assay). Meanwhile, protein levels of Bcl-2, cleaved-caspase 3, Bax, and MAPK1 (Mitogen-Activated Protein Kinase 1) proteins expression level were measured by Western blot. We found that Circ_0001679 was upregulated in LPS-induced MLE-12 cells, and silencing circ_0001679 attenuated the growth inhibition and suppressed apoptosis induced by LPS. Circ_0001679 knockdown also lowered levels of IL-6, IL-β and TNF-α, and prevent the activation of cleaved-caspase 3 protein. We further revealed that circ_0001679 functioned as a sponge of miR-338-3p to negatively regulate miR-338-3p activity. miR-338-3p downregulated its downstream target MAPK1, while the upregulation of circ_0001679 maintained a high-level expression of MAPK1 by suppressing miR-338-3p. Collectively, our study indicates that circ_0001679/miR-338-3p/MAPK1 axis may play an important role in the pathogenesis of acute lung injury (ALI).

Microarray Analysis Reveals the Changes in Circular RNA Expression and Molecular Mechanisms in Mice With Ventilator-Induced Lung Injury

Circular RNA (circRNA) expression profiles in lung tissues from mice with and without ventilator-induced lung injury (VILI) were analyzed using high-throughput sequencing and bioinformatics to clarify their potential role in VILI pathogenesis and provide valuable molecular markers for VILI diagnosis and treatment. A VILI mouse model was established using high-tidal volume ventilation, and lung tissue was stained with HE and TUNEL. The present study used high-throughput sequencing technology to analyze the expression profile of circRNAs in the lung tissue of mice with and without VILI. Bioinformatics was used to analyze the enrichment of differentially expressed circRNAs using Gene Ontology and KEGG to predict function. Among the top 10 circRNAs with significant differential expression, we used real-time quantitative polymerase chain reaction technology (qRT-PCR) to verify the accuracy of the high-throughput sequencing results and constructed the corresponding circRNA-miRNA-mRNA-specific binding network map using software prediction. The most upregulated circRNAs were novel_circ_0000899 and novel_circ_0014815, and the most downregulated circRNAs were novel_circ_0015069. A total of 14,347 circRNAs were detected using high-throughput sequencing. Compared to the control group, 285 circRNAs were abnormally and significantly expressed in the lung tissues of VILI mice (|log2(FC)| > 1, p < 0.05). A total of 171 circRNAs were significantly upregulated, and 114 circRNAs were significantly downregulated. Gene ontology analyses indicated that the differentially expressed circRNAs were involved in multiple biological functions, such as regulation of metabolic processes, protein phosphorylation, and chromatin organization. KEGG pathway analyses revealed that the Ras signaling pathway, rap1 signaling pathway, PI3K − Akt signaling pathway, and ECM receiver interaction were related to the differentially expressed circRNAs. The qRT-PCR verification results were generally consistent with the circRNA expression trends of the high-throughput sequencing data. The circRNA-miRNA-mRNA interaction network suggested that miRNAs and mRNAs related to circRNAs played a key role in VILI. Differentially expressed circRNAs were identified in the tissues of VILI mice using high-throughput sequencing combined with bioinformatics analysis, and the results lay a foundation for further study of the mechanism of circRNAs in the occurrence and development of VILI.

Circular RNA VMA21 ameliorates lung injury in septic rat via targeting microRNA-497-5p/CD2-associated protein axis

Sepsis was characterized via an acute inflammatory response to infection, often accompanying by multiple organ failure, particularly lung damage. Circular RNA (circRNA) played an important role in the pathology of a variety of diseases. However, the role of circRNA in sepsis-induced lung injury (LI) remained unknown. This study was to explore the expression and role of circVMA21 in sepsis LI and the possible molecular mechanism. The results manifested circVMA21 and CD2-associated protein (CD2AP) were down-regulated in lung tissue and lipopolysaccharide (LPS)-treated BEAS-2B, while microRNA (miR)-497-5p was up-regulated. A large number of deaths in rats after surgery of 72 h were caused via cecal ligation-perforation surgery, W/D value and Bax positive cells were increased, LI was caused, cell apoptosis, tumor necrosis factor-α, Interleukin (IL)-1β and IL-6 expression were promoted and Bcl-2 positive cells were decreased. Overexpression of circVMA21 ameliorated these phenomena. In addition, LPS-induced apoptosis and inflammation of BEAS-2B cells was improved via overexpression of circVMA21, while overexpression of miR-497-5P was opposite. Apoptosis, inflammation, and oxidative damage of BEAS-2B cells were aggravated via knockdown of circVMA21, but it was reversed by knockdown of miR-497-5p or overexpression of CD2AP. Mechanistically, CircVMA21 mediated CD2AP expression through competitive adsorption of miR-497-5p. In conclusion, this work showed circVMA21 improved LI in sepsis rats by targeting miR-497-5p/CD2AP axis, suggesting that circVMA21 may be a novel therapeutic target for sepsis-induced LI.

CircN4bp1 Facilitates Sepsis-Induced Acute Respiratory Distress Syndrome through Mediating Macrophage Polarization via the miR-138-5p/EZH2 Axis

We recently reported the differential circRNA expression patterns of the pulmonary macrophages in sepsis-induced acute respiratory distress syndrome (ARDS) mice model by microarray analysis. However, their function and hidden molecular mechanism in regulation of macrophage activation and inflammation remain poorly understood. In this study, we found that circN4bp1was overexpressed in PBMC and monocytes, and its expression levels were correlated with a poor prognosis in sepsis induced ARDS patients induced by sepsis. Knockdown of circN4bp1 inhibited the lung injury and improved the long-time survival through blunting the M1 macrophage activation in cecal ligation and puncture- (CLP-) induced ARDS mice. Moreover, bioinformatics analysis predicated a circN4bp1/miR-138-5p ceRNA network, which was confirmed by luciferase reporter assay and RNA binding protein immunoprecipitation (RIP). CircN4bp1 affected macrophage differentiation by binding to miR-138-5p, thus regulating the expression of EZH2 in vivo and ex vivo. Lastly, the m6A level of circN4bp1was found to be elevated in ARDS mice; inhibition of m6A methyltransferase METTL3 blocked this response in vitro. Therefore, circN4bp1 can function as a miR-138-5p sponge for the modulation of macrophage polarization through regulation the expression of EZH2 and may serve as a potential target and/or prognostic marker for ARDS patients following sepsis.

Regulatory Role of Non-Coding RNAs on Immune Responses During Sepsis

Sepsis is resulted from a systemic inflammatory response to bacterial, viral, or fungal agents. The induced inflammatory response by these microorganisms can lead to multiple organ system failure with devastating consequences. Recent studies have shown altered expressions of several non-coding RNAs such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs) during sepsis. These transcripts have also been found to participate in the pathogenesis of multiple organ system failure through different mechanisms. NEAT1, MALAT1, THRIL, XIST, MIAT and TUG1 are among lncRNAs that participate in the pathoetiology of sepsis-related complications. miR-21, miR-155, miR-15a-5p, miR-494-3p, miR-218, miR-122, miR-208a-5p, miR-328 and miR-218 are examples of miRNAs participating in these complications. Finally, tens of circRNAs such as circC3P1, hsa_circRNA_104484, hsa_circRNA_104670 and circVMA21 and circ-PRKCI have been found to affect pathogenesis of sepsis. In the current review, we describe the role of these three classes of noncoding RNAs in the pathoetiology of sepsis-related complications.

Isoorientin suppresses sepsis-induced acute lung injury in mice by activating an EPCR-dependent JAK2/STAT3 pathway

Sepsis is a systemic inflammatory syndrome, and acute lung injury (ALI) is one of the most common fatal complications of sepsis. Isoorientin (ISO) exerts a momentous role in the regulation of inflammation. However, whether ISO has a protective effect on sepsis-induced ALI remains unknown. This research aimed to elucidate the function of ISO on sepsis-induced ALI and its mechanism. In this study, the sepsis-induced ALI was established in the male C57BL/6 J mice. Functionally, ISO reduced the total protein concentration in BALF, lung wet/dry ratio and the numbers of neutrophils and macrophages in BALF as well as ameliorated lung injury. Besides, ISO treatment decreased the cytokine expressions and oxidative stress, and repressed the adhesion and migration of inflammatory cells induced by CLP. Mechanistically, ISO reduced the shedding of EPCR in the endothelial cell membrane; ISO treatment activated the JAK2/STAT3 signaling pathway through EPCR and the JAK2/STAT3 pathway inhibitors repressed the anti-inflammatory and antioxidant effects of ISO. In general, ISO suppressed sepsis-induced ALI in mice by activating an EPCR-dependent JAK2/STAT3 pathway.

RETRACTED: Exosomal microRNA-16-5p from adipose mesenchymal stem cells promotes TLR4-mediated M2 macrophage polarization in septic lung injury

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). The authors have requested that this paper be retracted as they were unable to replicate the experimental data reported in Figure 1A. The authors posit that changes in reagents or experimental conditions might be the source of their inability to do so. Additional concerns were raised about the reliability of the Western blot results in Figure 1E, Figure 4B and F, Figure 5B, and Figure 6B, as regarding ‘morphology space’ similarities contained within a series of papers with distinctive eyebrow blots, tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0 [nam11.safelinks.protection.outlook.com] [nam11.safelinks.protection.outlook.com]). The journal requested the authors comment on these concerns and provide raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.

RETRACTED: LncRNA NEAT1 inhibition upregulates miR-16-5p to restrain the progression of sepsis-induced lung injury via suppressing BRD4 in a mouse model

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the reliability of the Western blot results in Figs. 5B and 6B, which appear to have the same eyebrow shaped phenotype as many other publications tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0 [docs.google.com]). The journal requested the corresponding author comment on these concerns and provide the raw data. However, the authors were not responsive to the request for comment. Since original data could not be provided, the overall validity of the results could not be confirmed. Therefore, the Editor-in-Chief decided to retract the article.

Effect of Baicalin on Transcriptome Changes in Piglet Vascular Endothelial Cells Induced by a Combination of Glaesserella parasuis and Lipopolysaccharide

Glaesserella parasuis causes porcine Glässer's disease and lipopolysaccharide (LPS) induces acute inflammation and pathological damage. Baicalin has antioxidant, antimicrobial, and anti-inflammatory functions. Long noncoding RNAs (lncRNAs) play key regulatory functions during bacterial infection. However, the role of lncRNAs in the vascular dysfunction induced by a combination of G. parasuis and LPS during systemic inflammation and the effect of baicalin on lncRNA expression induced in porcine aortic vascular endothelial cells (PAVECs) by a combination of G. parasuis and LPS have not been investigated. In this study, we investigated the changes in lncRNA and mRNA expression induced in PAVECs by G. parasuis, LPS, or a combination of G. parasuis and LPS, and the action of baicalin on lncRNA expression induced in PAVECs by the combination of G. parasuis and LPS. Our results showed 133 lncRNAs and 602 genes were differentially expressed when PAVECs were stimulated with the combination of G. parasuis and LPS, whereas 107 lncRNAs and 936 genes were differentially expressed when PAVECs were stimulated with the combination of G. parasuis and LPS after pretreatment with baicalin. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed the dominant signaling pathways triggered by the combination of G. parasuis and LPS were the tumor necrosis factor signaling pathway, phosphatidylinositol signaling system, and inositol phosphate metabolism. Protein-protein interaction network analysis showed the differentially expressed target genes of the differentially expressed lncRNAs (DELs) were related to each other. A coexpression analysis indicated the expression levels of the DELs were co-regulated with those of their differentially expressed target genes. This is the first study to systematically compare the changes in lncRNAs and mRNAs in PAVECs stimulated with a combination of G. parasuis and LPS. Our data clarified the mechanisms underlying the vascular inflammation and damage triggered by G. parasuis and LPS, and it may provide novel targets for the treatment of LPS-induced systemic inflammation.

CircC3P1 attenuated pro-inflammatory cytokine production and cell apoptosis in acute lung injury induced by sepsis through modulating miR-21

Acute lung injury (ALI) induced by sepsis is characterized by an inflammatory process related to the up‐regulation of inflammatory cytokines and chemokines. In the present study, we explored the role of circC3P1 in sepsis‐induced ALI in vitro and in vivo. The caecal ligation and puncture (CLP)‐induced sepsis model was established through CLP surgery. Forty adult male C57BL/6 mice were randomly assigned into sham, CLP, CLP + vector and CLP + circC3P1 (each n = 10). Primary murine pulmonary microvascular endothelial cells (MPVECs) were transfected with circC3P1 or empty vector 24 hours prior to LPS treatment via Lipofectamine 2000. The expressions of circC3P1, tumour necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6) and IL‐1β were evaluated after 6‐h LPS treatment. Cell apoptosis was evaluated via flow cytometry. The CLP group demonstrated pulmonary morphological abnormalities, increased concentrations of TNF‐α, IL‐6 and IL‐1β in the lung tissue, compared with the sham group. MPVECs treated with LPS significantly elevated TNF‐α, IL‐6 and IL‐1β levels and increased cell apoptosis than that in the control group. The circC3P1 overexpression in sepsis‐induced ALI mice attenuated pulmonary injury, inflammation and apoptosis. Besides, circC3P1 revealed anti‐inflammatory and anti‐apoptotic effect in MPVEC‐treated LPS. CircC3P1 overexpression reduced cell apoptosis and pro‐inflammatory cytokines levels via down‐regulating miR‐21. CircC3P1 attenuated pro‐inflammatory cytokine production and cell apoptosis in ALI induced by sepsis through modulating miR‐21, indicating that circC3P1 is a promising therapeutic biomarker for sepsis‐induced ALI.