Inhibition of miR-155 alleviates sepsis-induced inflammation and intestinal barrier dysfunction by inactivating NF-κB signaling

The dual effects of dexmedetomidine on intestinal barrier and intestinal motility during sepsis

BACKGROUND

Sepsis, characterized by dysregulated host responses to infection, remains a critical global health concern, with high morbidity and mortality rates. The gastrointestinal tract assumes a pivotal role in sepsis due to its dual functionality as a protective barrier against injurious agents and as a regulator of motility. Dexmedetomidine, an α2-adrenergic agonist commonly employed in critical care settings, exhibits promise in influencing the maintenance of intestinal barrier integrity during sepsis. However, its impact on intestinal motility, a crucial component of intestinal function, remains incompletely understood.

METHODS

In this study, we investigated dexmedetomidine's multifaceted effects on intestinal barrier function and motility during sepsis using both in vitro and in vivo models. Sepsis was induced in Sprague-Dawley rats via cecal ligation and puncture. Rats were treated with dexmedetomidine post-cecal ligation and puncture, and various parameters were assessed to elucidate dexmedetomidine's impact.

RESULTS

Our findings revealed a dichotomous influence of dexmedetomidine on intestinal physiology. In septic rats, dexmedetomidine administration resulted in improved intestinal barrier integrity, as evidenced by reduced mucosal hyper-permeability and morphological alterations. However, a contrasting effect was observed on intestinal motility, as dexmedetomidine treatment inhibited both the frequency and amplitude of contractions in isolated intestinal strips and decreased the distance of ink migration in vivo. Additionally, dexmedetomidine suppressed the secretion of pro-motility hormones while having no influence on hormones that inhibit intestinal peristalsis.

CONCLUSION

The study revealed that during sepsis, dexmedetomidine exhibited protective effects on barrier integrity, although concurrently it hindered intestinal motility, partly attributed to its modulation of pro-motility hormone secretion. These findings underscore the necessity of a comprehensive understanding of dexmedetomidine's impact on multiple facets of gastrointestinal physiology in sepsis management, offering potential implications for therapeutic strategies and patient care.

Water decoction of Pericarpium citri reticulatae and Amomi fructus ameliorates alcohol-induced liver disease involved in the modulation of gut microbiota and TLR4/NF-κB pathway

Introduction

Alcohol consumption alters the diversity and metabolic activities of gut microbiota, leading to intestinal barrier dysfunction and contributing to the development of alcoholic liver disease (ALD), which is the most prevalent cause of advanced liver diseases. In this study, we investigated the protective effects and action mechanism of an aqueous extraction of Pericarpium citri reticulatae and Amomi fructus (PFE) on alcoholic liver injury.

Methods

C57BL/6 mice were used to establish the mouse model of alcoholic liver injury and orally administered 500 and 1,000 mg/kg/d of PFE for 2 weeks. Histopathology, immunohistochemistry, immunofluorescence, Western blotting, qRT-PCR, and 16S rDNA amplicon sequencing were used to analyze the mechanism of action of PFE in the treatment of alcohol-induced liver injury.

Results

Treatment with PFE significantly improved alcohol-induced liver injury, as illustrated by the normalization of serum alanine aminotransferase, aspartate aminotransferase, total triglyceride, and cholesterol levels in ALD mice in a dose-dependent manner. Administration of PFE not only maintained the intestinal barrier integrity prominently by upregulating mucous production and tight junction protein expressions but also sensibly reversed the dysregulation of intestinal microecology in alcohol-treated mice. Furthermore, PFE treatment significantly reduced hepatic lipopolysaccharide (LPS) and attenuated oxidative stress as well as inflammation related to the TLR4/NF-κB signaling pathway. The PFE supplementation also significantly promoted the production of short-chain fatty acids (SCFAs) in the ALD mice.

Conclusion

Administration of PFE effectively prevents alcohol-induced liver injury and may also regulate the LPS-involved gut-liver axis; this could provide valuable insights for the development of drugs to prevent and treat ALD.

Zn(II)-curcumin prevents cadmium-aggravated diabetic nephropathy by regulating gut microbiota and zinc homeostasis

Background: Diabetic nephropathy (DN) is known as the most common complication of diabetes, resulting from a complex inheritance-environment interaction without effective clinical treatments. Herein, we revealed the protective effects and mechanisms of Zn(II)-curcumin, a curcumin derivative, against streptozotocin-induced DN in rats in the presence or absence of cadmium exposure. Methods: The present study focused on investigating the therapy of Zn(II)-curcumin against cadmium-aggravated DN by regulating gut microbiota, metabolism, inflammation and zinc homeostasis based on pathological changes, TLR4/NF-κB signaling pathway, inductively coupled plasma-mass spectrometry (ICP-MS), 16S rRNA gene sequencing and gas chromatography-mass spectrometer (GC-MS). Results: We found Zn(II)-curcumin significantly mitigated the cadmium-aggravated phenotypes of diabetic nephropathy, as indicated by the remission of renal dysfunction, pathological changes, inflammation and zinc dyshomeostasis in streptozotocin-treated rats exposed to cadmium. Administration of Zn(II)-curcumin significantly alleviated the dysbiosis of gut microbiota and the changes of serum metabolite profiles in rats treated with streptozotocin in combination with cadmium. Notably, fecal microbial transplantation identified the ability of Zn(II)-curcumin to regulate renal function, inflammation and zinc homeostasis was partly dependent on the gut microbiota. Conclusion: These findings revealed that Zn(II)-curcumin alleviated cadmium-aggravated diabetic nephropathy by reshaping the gut microbiota and zinc homeostasis, which provided unique insights into the mechanisms of the treatment and prevention of diabetic nephropathy.

Cubic liquid crystals containing propolis flavonoids as in situ thermo-sensitive hydrogel depots for periodontitis treatment: Preparation, pharmacodynamics and therapeutic mechanisms

Propolis has a long ethnopharmacological history for oral periodontal diseases treatment. Propolis flavonoids are main active components for anti-inflammation and tissue protection. However, the intractable dissolution properties of propolis flavonoids and complex oral environment pose great challenges for periodontal delivery. In addition, the therapeutic mechanism as well as the therapeutic correlation of inflammation resolution and tissue regeneration remain unclear for propolis flavonoids. In this study, we constructed an in situ thermosensitive depot systems using total flavonoids from propolis-loaded cubic liquid crystals (TFP-CLC) hydrogel for periodontal delivery. TFP-CLC inhibited inflammatory cell infiltration, reactive oxygen species and the expression of inflammatory cytokines of NF-κB and IL-1β. In addition, alveolar bone and collagen were significantly regenerated after TFP-CLC administration according to micro-CT and immunohistochemistry. Mechanism studies suggested that TFP-CLC alleviated inflammation and promoted alveolar bone repair via regulating TLR4/MyD88/NF-κB p65 and RANK/NF-κB signaling pathways, respectively. Correlation analysis further confirmed that the inflammatory resolution produced by TFP-CLC could accelerate periodontal tissue regeneration. In summary, TFP-CLC is a promising multifunctional in situ thermo-sensitive hydrogel depots for periodontitis treatment.

Clinical role of serum microRNA-155 in early diagnosis and prognosis of septic patients with acute kidney injury

BACKGROUND AND PURPOSE

Acute kidney injury (AKI) is a common complication in patients with sepsis, and early detection and timely treatment are crucial. This article aims to explore the clinical role of microRNA-155 (miR-155) in early diagnosis and prognosis evaluation of septic patients with acute kidney injury.

METHODS

We collected the blood samples of septic patients and measured the relative expression of serum miR-155 by RT-qPCR, and drew the receiver operating characteristic (ROC) curves to evaluate its early diagnosis for septic AKI.

RESULTS

The relative expression of miR-155 in the septic AKI was significantly higher than that in the septic non-AKI, and increased with the aggravation of renal function damage. The ROC curve of miR-155 for the diagnosis of septic AKI was 1.91 (95% CI: 1.61-2.19). When the optimal cut-off value of miR-155 expression was 2.37, its sensitivity for diagnosing septic AKI was 91.12% (95% CI: 80.41-95.07%), and its specificity was 84.52% (95% CI: 71.74-89.36%). Furthermore, the severity of kidney injury, SOFA score, APACHE II score and miR-155 were the risk factors affecting the prognosis of septic patients with AKI.

CONCLUSION

Serum miR-155 can be used as a novel biomarker for the early diagnosis of septic AKI, and also has important clinical value in the prognosis evaluation of septic patients with AKI.

PAK1 Promotes Inflammation Induced by Sepsis through the Snail/CXCL2 Signaling Pathway

Sepsis is a severe syndrome characterized by organ dysfunction, resulting from a systemic imbalance in response to infection. PAK1 plays a critical role in various diseases. The present study aimed to explore and delineate the mechanism of PAK1 in inflammation induced by sepsis. Bioinformatics analysis was performed to assess PAK1, snail, and CXCL2 expression in the whole blood of septic patients and the pathways enriched with PAK1. To simulate the sepsis model, THP-1 cells were stimulated with lipopolysaccharide. Gene expression was evaluated using qRT-PCR, while cell viability was assessed using CCK-8 assay. Cell apoptosis was tested with flow cytometry. Expression of inflammatory factors in cells following different treatments was analyzed using the enzyme linked immunosorbent assay (ELISA). Dual-luciferase and chromatin immunoprecipitation assays were conducted to verify the binding relationship between PAK1 and the snail. Mouse models of cecal ligation and puncture were established, and hematoxylin and eosin staining and ELISA were employed to detect the infiltration levels of inflammatory cells and the expression of related protective factors in lung, liver, and kidney tissues. The results demonstrated upregulation of PAK1, snail, and CXCL2 in the whole blood of septic patients, with PAK1 being enriched in the chemokine-related pathway. Knockdown of PAK1 significantly promoted the apoptosis of LPS-stimulated THP-1 cells and inhibited the expression of inflammatory factors. PAK1 upregulated the expression of the snail, which in turn promoted the expression of CXCL2. Thus, PAK1 mediated the sepsis-induced inflammatory response through the snail/CXCL2 pathway. In conclusion, PAK1 played a role in promoting inflammation induced by sepsis through the snail/CXCL2 axis, thereby providing a potential therapeutic target for the management of sepsis.

MIR-155 PROMOTES ACUTE ORGAN INJURY IN LPS-INDUCED ENDOTOXEMIC MICE BY ENHANCING CCL-2 EXPRESSION IN MACROPHAGES

ABSTRACT

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Macrophages play important roles in the inflammatory process of sepsis by secreting chemokines. Chemokine (CC-motif) ligand 2 (CCL-2) is one of the main proinflammatory chemokines secreted by macrophages that plays a critical role in the recruitment of more monocytes and macrophages to the sites of injury in sepsis, but the mechanisms that regulate CCL-2 expression in macrophages during sepsis are still unknown. In the present study, by using the LPS-induced endotoxemia model, we found that LPS induced the expression of microRNA (miR)-155 and CCL-2 in endotoxemic mice and RAW264.7 cells. MiR-155 mimics or miR-155 inhibitor treatment experiment suggested that miR-155 was sufficient to increase LPS-induced CCL-2 expression in macrophages, but miR-155 was not the only factor promoting CCL-2 expression. We further demonstrated that miR-155-induced increase of CCL-2 promoted chemotaxis of additional macrophages, which subsequently enhanced lung injury in endotoxemic mice. Serum/glucocorticoid regulated kinase family member 3 (SGK3), a potential target of miR-155, was identified by RNA sequencing and predicted by TargetScan and miRDB. We further confirmed miR-155 regulated SGK3 to increase LPS-induced CCL-2 by using miR-155 mimics and SGK3 overexpression. Thus, our study demonstrates that miR-155 targets SGK3 to increase LPS-induced CCL-2 expression in macrophages, which promotes macrophage chemotaxis and enhances organs injury during endotoxemia. Our study contributed to a better understanding of the mechanisms underlying the inflammatory response during sepsis.

L-arginine attenuates Streptococcus uberis-induced inflammation by decreasing miR155 level

L-arginine, as an essential substance of the immune system, plays a vital role in innate immunity. MiR155, a multi-functional microRNA, has gained importance as a regulator of homeostasis in immune cells. However, the immunoregulatory mechanism between L-arginine and miR155 in bacterial infections is unknown. Here, we investigated the potential role of miR155 in inflammation and the molecular regulatory mechanisms of L-arginine in Streptococcus uberis (S. uberis) infections. And we observed that miR155 was up-regulated after infection, accompanying the depletion of L-arginine, leading to metabolic disorders of amino acids and severe tissue damage. Mechanically, the upregulated miR155 mediated by the p65 protein played a pro-inflammatory role by suppressing the suppressor of cytokine signaling 6 (SOCS6)-mediated p65 ubiquitination and degradation. This culminated in a violently inflammatory response and tissue damage. Interestingly, a significant anti-inflammatory effect was revealed in L-arginine supplementation by reducing miR155 production via inhibiting p65. This work firstly uncovers the pro-inflammatory role of miR155 and an anti-inflammatory mechanism of L-arginine in S.uberis infection with a mouse mastitis model. Collectively, we provide new insights and strategies for the prevention and control of this important pathogen, which is of great significance for ensuring human food health and safety.

MiR-106a-5p by Targeting MAP3K2 Promotes Repair of Oxidative Stress Damage to the Intestinal Barrier in Prelaying Ducks

Under caged stress conditions, severe disruptions in duck intestinal barrier function, which adversely affect economic performance, have been observed. MiRNAs play a crucial role in cellular processes, but the mechanisms underlying their involvement in repairing oxidative stress-induced damage to duck intestinal barriers have not been elucidated. We performed miRNA-seq and protein tandem mass tagging (TMT) sequencing and identified differentially expressed miRNAs and proteins in oxidative stress-treated ducks. Dual-luciferase reporter vector experiments, RT-qPCR, and Western blotting revealed the regulatory role of apla-miR-106a-5p/MAP3K2 in intestinal barrier damage repair. The results showed that oxidative stress led to shortened villi and deepened crypts, impairing intestinal immune function. Significant downregulation of apla-miR-106a-5p was revealed by miRNA-seq, and the inhibition of its expression not only enhanced cell viability but also improved intestinal barrier function. TMT protein sequencing revealed MAP3K2 upregulation in caged-stressed duck intestines, and software analysis confirmed MAP3K2 as the target gene of apla-miR-106a-5p. Dual-fluorescence reporter gene experiments demonstrated direct targeting of MAP3K2 by apla-miR-106a-5p. RT-qPCR showed no effect on MAP3K2 expression, while Western blot analysis indicated that MAP3K2 protein expression was suppressed. In summary, apla-miR-106a-5p targets MAP3K2, regulating gene expression at the transcriptional level and facilitating effective repair of intestinal barrier damage. This discovery provides new insights into the molecular mechanisms of physiological damage in ducks under caged stress, offering valuable guidance for related research.

Monotropein induces autophagy through activation of the NRF2/PINK axis, thereby alleviating sepsis-induced colonic injury

Sepsis is a systemic inflammatory disease that is caused by a dysregulated host response to infection and is a life-threatening organ dysfunction that affects many organs, which includes the colon. Mounting evidence suggests that sepsis-induced colonic damage is a major contributor to organ failure and cellular dysfunction. Monotropein (MON) is the major natural compound in the iris glycoside that is extracted from Morendae officinalis radix, which possesses the potent pharmacological activities of anti-inflammatory and antioxidant properties. This research evaluated whether MON is able to alleviate septic colonic injury in mice by cecal ligation and puncture. Colonic tissues were analyzed using histopathology, immunofluorescence, quantitative real-time polymerase chain reaction, and Western blot methods. It was initially discovered that MON reduced colonic damage in infected mice, in addition to inflammation, apoptosis, and oxidative stress in colonic tissues, while it activated autophagy, with the NRF2/keap1 and PINK1/Parkin pathways also being activated. Through the stimulation of NCM460 cells with lipopolysaccharides, an in vitro model of sepsis was created as a means of further elucidating the potential mechanisms of MON. In the in vitro model, it was found that MON could still activate the NRF2/keap1, PINK1/Parkin, and autophagy pathways. However, when MON was paired with the NRF2 inhibitor ML385, it counteracted MON-induced activation of PINK1/Parkin and autophagy, while also promoting inflammatory response and apoptosis in NCM460 cells. Therefore, the data implies that MON could play a therapeutic role through the activation of the NFR2/PINK pathway as a means of inducing autophagy to alleviate the oxidative stress in colonic tissues that is induced by sepsis, which will improve inflammation and apoptosis in colonic tissues.

Upregulated Tβ4 expression in inflammatory bowel disease impairs the intestinal mucus barrier by inhibiting autophagy in mice

Disrupted intestinal barrier homeostasis is fundamental to inflammatory bowel disease. Thymosin β4 (Tβ4) improves inflammation and has beneficial effects in dry-eye diseases, but its effects on the intestinal mucus barrier remain unknown. Therefore, this study evaluated the underlying regulatory mechanisms and effects of Tβ4 by examining Tβ4 expression in a mouse model with dextran sodium sulfate (DSS)-induced colitis and colonic barrier damage. Additionally, we intraperitoneally injected C57BL/6 mice with Tβ4 to assess barrier function, microtubule-associated protein 1 light chain 3 (LC3II) protein expression, and autophagy. Finally, normal human colon tissue and colon carcinoma cells (Caco2) were cultured to verify Tβ4-induced barrier function and autophagy changes. Mucin2 levels decreased, microbial infiltration increased, and Tβ4 expression increased in the colitis mouse model versus the control mice, indicating mucus barrier damage. Moreover, Tβ4-treated C57BL/6 mice had damaged intestinal mucus barriers and decreased LC3II levels. Tβ4 also inhibited colonic mucin2 production, disrupted tight junctions, and downregulated autophagy; these results were confirmed in Caco2 cells and normal human colon tissue. In summary, Tβ4 may be implicated in colitis by compromising the integrity of the intestinal mucus barrier and inhibiting autophagy. Thus, Tβ4 could be a new diagnostic marker for intestinal barrier defects.

Ghrelin/GHSR Axis Induced M2 Macrophage and Alleviated Intestinal Barrier Dysfunction in a Sepsis Rat Model by Inactivating E2F1/NF-κB Signaling

Sepsis is an inflammatory reaction disorder state that is induced by infection. The activation and regulation of the immune system play an essential role in the development of sepsis. Our previous studies have shown that ghrelin ameliorates intestinal dysfunction in sepsis. Very little is known about the mechanism of ghrelin and its receptor (GHSR) on the intestinal barrier and the immune function of macrophage regulation. Our research is to investigate the regulatory effect and molecular mechanism of the ghrelin/GHSR axis on intestinal dysfunction and macrophage polarization in septic rats. A rat model of sepsis was established by cecal ligation and puncture (CLP) operation. Then, the sepsis rats were treated with a ghrelin receptor agonist (TZP-101) or ghrelin inhibitor (obestatin). The results suggested that TZP-101 further enhanced ghrelin and GHSR expressions in the colon and spleen of septic rats and obestatin showed the opposite results. Ghrelin/GHSR axis ameliorated colonic structural destruction and intestinal epithelial tight junction injury in septic rats. In addition, the ghrelin/GHSR axis promoted M2-type polarization of macrophages, which was characterized by the decreases of IL-1β, IL-6, and TNF-α, as well as the increase of IL-10. Mechanistically, the ghrelin/GHSR axis promoted E2F2 expression and suppressed the activation of the NF-κB signaling pathway in septic rats. Collectively, targeting ghrelin/GHSR during sepsis may represent a novel therapeutic approach for the treatment of intestinal barrier injury.

Gut liver brain axis in diseases: the implications for therapeutic interventions

Gut-liver-brain axis is a three-way highway of information interaction system among the gastrointestinal tract, liver, and nervous systems. In the past few decades, breakthrough progress has been made in the gut liver brain axis, mainly through understanding its formation mechanism and increasing treatment strategies. In this review, we discuss various complex networks including barrier permeability, gut hormones, gut microbial metabolites, vagus nerve, neurotransmitters, immunity, brain toxic metabolites, β-amyloid (Aβ) metabolism, and epigenetic regulation in the gut-liver-brain axis. Some therapies containing antibiotics, probiotics, prebiotics, synbiotics, fecal microbiota transplantation (FMT), polyphenols, low FODMAP diet and nanotechnology application regulate the gut liver brain axis. Besides, some special treatments targeting gut-liver axis include farnesoid X receptor (FXR) agonists, takeda G protein-coupled receptor 5 (TGR5) agonists, glucagon-like peptide-1 (GLP-1) receptor antagonists and fibroblast growth factor 19 (FGF19) analogs. Targeting gut-brain axis embraces cognitive behavioral therapy (CBT), antidepressants and tryptophan metabolism-related therapies. Targeting liver-brain axis contains epigenetic regulation and Aβ metabolism-related therapies. In the future, a better understanding of gut-liver-brain axis interactions will promote the development of novel preventative strategies and the discovery of precise therapeutic targets in multiple diseases.

Xuebijing injection protects sepsis induced myocardial injury by mediating TLR4/NF-κB/IKKα and JAK2/STAT3 signaling pathways

OBJECTIVE

Compelling evidence has demonstrated that Xuebijing (XBJ) exerted protective effects against SIMI. The aims of this study were to investigate whether TLR4/IKKα-mediated NF-κB and JAK2/STAT3 pathways were involved in XBJ's cardio-protection during sepsis and the mechanisms.

METHODS

In this study, rats were randomly assigned to three groups: Sham group; CLP group; XBJ group. Rats were treated with XBJ or sanitary saline after CLP. Echocardiography, myocardial enzymes and HE were used to detect cardiac function. IL-1β, IL-6 and TNF-α in serum were measured using ELISA kits. Cardiomyocyte apoptosis were tested by TUNEL staining. The protein levels of Bax, Bcl-2, Bcl-xl, Cleaved-Caspase 3, Cleaved-Caspase 9, Cleaved-PARP, TLR4, p-NF-κB, p-IKKα, p-JAK2 and p-STAT3 in the myocardium were assayed by western blotting. And finally, immunofluorescence was used to assess the level of p-JAK2 and p-STAT3 in heart tissue.

RESULTS

The results of echocardiography, myocardial enzyme and HE test showed that XBJ could significantly improve SIMI. The IL-1β, IL-6 and TNF-α levels in the serum were markedly lower in the XBJ group than in the CLP group (p<0.05). TUNEL staining's results showed that XBJ ameliorated CLP-induced cardiomyocyte apoptosis. Meanwhile, XBJ downregulated the protein levels of Bax, Cleaved-Caspase 3, Cleaved-Caspase 9, Cleaved-PARP, TLR4, p-NF-κB, p-IKKα, p-JAK2 and p-STAT3, as well as upregulated the protein levels of Bcl-2, Bcl-xl (p <0.05).

CONCLUSIONS

In here, we observed that XBJ's cardioprotective advantages may be attributable to its ability to suppress inflammation and apoptosis via inhibiting the TLR4/ IKKα-mediated NF-κB and JAK2/STAT3 pathways during sepsis.

Curcumin Alleviates Singapore Grouper Iridovirus-Induced Intestine Injury in Orange-Spotted Grouper (Epinephelus coioides)

Singapore grouper iridovirus (SGIV) is a new ranavirus species in the Iridoviridae family, whose high lethality and rapid spread have resulted in enormous economic losses for the aquaculture industry. Curcumin, a polyphenolic compound, has been proven to possess multiple biological activities, including antibacterial, antioxidant, and antiviral properties. This study was conducted to determine whether curcumin protected orange-spotted grouper (Epinephelus coioides) from SGIV-induced intestinal damage by affecting the inflammatory response, cell apoptosis, oxidative stress, and intestinal microbiota. Random distribution of healthy orange-spotted groupers (8.0 ± 1.0 cm and 9.0 ± 1.0 g) into six experimental groups (each group with 90 groupers): Control, DMSO, curcumin, SGIV, DMSO + SGIV, and curcumin + SGIV. The fish administered gavage received DMSO dilution solution or 640 mg/L curcumin every day for 15 days and then were injected intraperitoneally with SGIV 24 h after the last gavage. When more than half of the groupers in the SGIV group perished, samples from each group were collected for intestinal health evaluation. Our results showed that curcumin significantly alleviated intestine damage and repaired intestinal barrier dysfunction, which was identified by decreased intestine permeability and serum diamine oxidase (DAO) activity and increased expressions of tight junction proteins during SGIV infection. Moreover, curcumin treatment suppressed intestinal cells apoptosis and inflammatory response caused by SGIV and protected intestinal cells from oxidative injury by enhancing the activity of antioxidant enzymes, which was related to the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. Moreover, we found that curcumin treatment restored the disruption of the intestinal microbiota caused by SGIV infection. Our study provided a theoretical basis for the functional development of curcumin in aquaculture by highlighting the protective effect of curcumin against SGIV-induced intestinal injury.

Advancements in understanding the role of microRnas in regulating macrophage polarization during acute lung injury

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical and life-threatening illness that causes severe dyspnea, and respiratory distress and is often caused by a variety of direct or indirect factors that damage the alveolar epithelium and capillary endothelial cells, leading to inflammation factors and macrophage infiltration. Macrophages play a crucial role in the progression of ALI/ARDS, exhibiting different polarized forms at different stages of the disease that control the disease outcome. MicroRNAs (miRNA) are conserved, endogenous, short non-coding RNAs composed of 18-25 nucleotides that serve as potential markers for many diseases and are involved in various biological processes, including cell proliferation, apoptosis, and differentiation. In this review, we provide a brief overview of miRNA expression in ALI/ARDS and summarize recent research on the mechanism and pathways by which miRNAs respond to macrophage polarization, inflammation, and apoptosis. The characteristics of each pathway are also summarized to provide a comprehensive understanding of the role of miRNAs in regulating macrophage polarization during ALI/ARDS.

Nogo-B inhibition restricts ulcerative colitis via inhibiting p68/miR-155 signaling pathway

BACKGROUND & AIMS

Ulcerative colitis (UC) is a main type of inflammatory bowel diseases which spreads globally during the westernization of lifestyle over the past few decades. However, the cause of UC is still not fully understood. We aimed to disclose the role of Nogo-B in the development of UC.

METHODS

Nogo-deficiency (Nogo^-/-) and wild-type male mice were treated with dextran sodium sulfate (DSS) to conduct a UC model, followed by determination of colon and serum inflammatory cytokines level. RAW264.7, THP1 and NCM460 cells were used to determine macrophage inflammation as well as proliferation and migration of NCM460 cells under Nogo-B or miR-155 intervention.

RESULTS

Nogo deficiency significantly reduced DSS-induced weight loss, colon length and weight reduction, and inflammatory cells accumulation in the intestinal villus, while increased the expression of tight junctions (TJs) proteins (Zonula occludens-1, Occludin) and adherent junctions (AJs) proteins (E-cadherin, α-catenin), implying that Nogo deficiency attenuated DSS-induced UC. Mechanistically, Nogo-B deficiency reduced TNFα, IL-1β and IL-6 levels in the colon, serum, RAW264.7 cells and THP1-derived macrophages. Furthermore, we identified that Nogo-B inhibition can reduce the maturation of miR-155, which is essential for Nogo-B-affected inflammatory cytokines expression. Interestingly, we determined that Nogo-B and p68 can interact with each other to promote the expression and activation of Nogo-B and p68, thus facilitating miR-155 maturation to induce macrophage inflammation. Blocking p68 inhibited Nogo-B, miR-155, TNFα, IL-1β and IL-6 expression. Moreover, the culture medium collected from Nogo-B overexpressed macrophages can inhibit enterocytes NCM460 cells proliferation and migration.

CONCLUSION

We disclose that Nogo deficiency reduced DSS-induced UC via inhibiting p68-miR-155-activated inflammation. Our results indicate that Nogo-B inhibition serves as a new potential therapeutic candidate for the prevention and treatment of UC.

LncRNA GAS5 suppresses inflammatory responses by inhibiting HMGB1 release via miR-155-5p/SIRT1 axis in sepsis

Sepsis comprises a lethal immunologic response due to infection. Increasingly, evidence has demonstrated the important role of long non-coding RNA growth arrest-specific transcript 5 (GAS5) in the regulation of sepsis. Nevertheless, the mechanisms by which GAS5 participates in the progression of sepsis remain unclear. Our study demonstrated the role and underlying mechanism of GAS5 in regulating lipopolysaccharide (LPS)-induced inflammation. In this study, GAS5 expression was found to be markedly decreased in serum samples of sepsis patients and a sepsis mouse model, and was negatively related with HMGB1 expression. GAS5 overexpression inhibited cell inflammatory responses by decreasing HMGB1 release. Furthermore, GAS5 inhibited LPS-mediated hyperacetylation and the release of HMGB1 by increasing the expression of sirtuin1 (SIRT1). Additionally, upregulated GAS5 attenuated inflammatory responses in vitro and vivo, and the knockdown of a miR-155-5p mimic and SIRT1 rescued the effects of GAS5 upregulation. Mechanistically, GAS5 sponged miR-155-5p to upregulate SIRT1, thereby inhibiting HMGB1 acetylation and release. In conclusion, our findings indicate that GAS5 suppresses inflammatory responses by modulating the miR-155-5p/SIRT1/HMGB1 axis in sepsis, providing a novel therapeutic target for inflammation in sepsis.

The Polo-Like Kinase 1-Mammalian Target of Rapamycin Axis Regulates Autophagy to Prevent Intestinal Barrier Dysfunction During Sepsis

The intestines play a crucial role in the development of sepsis. The balance between autophagy and apoptosis in intestinal epithelial cells is dynamic and determines intestinal permeability. The present study focused on the potential role of autophagy in sepsis-induced intestinal barrier dysfunction and explored the mechanisms in vivo and in vitro. Excessive apoptosis in intestinal epithelia and a disrupted intestinal barrier were observed in septic mice. Promoting autophagy with rapamycin reduced intestinal epithelial apoptosis and restored intestinal barrier function, presenting as decreased serum diamine oxidase (DAO) and fluorescein isothiocyanate-dextran 40 (FD40) levels and increased expression of zonula occludens-1 (ZO-1) and Occludin. Polo-like kinase 1 (PLK1) knockdown in mice ameliorated intestinal epithelial apoptosis and the intestinal barrier during sepsis, whereas these effects were reduced with chloroquine and enhanced with rapamycin. PLK1 also promoted cell autophagy and improved lipopolysaccharide-induced apoptosis and high permeability in vitro. Moreover, PLK1 physically interacted with mammalian target of rapamycin (mTOR) and participated in reciprocal regulatory crosstalk in intestinal epithelial cells during sepsis. This study provides novel insight into the role of autophagy in sepsis-induced intestinal barrier dysfunction and indicates that the PLK1-mTOR axis may be a promising therapeutic target for sepsis.

Tetrahedral-Framework Nucleic Acid Loaded with MicroRNA-155 Enhances Immunocompetence in Cyclophosphamide-Induced Immunosuppressed Mice by Modulating Dendritic Cells and Macrophages

Nanomaterials are often used as immunomodulators because they can be tailored by a controllable process. In this work, a complex based on a tetrahedral framework nucleic acid delivery system and MicroRNA-155, known as T-155, is synthesized for the modulation of immunosuppression. In vivo, T-155 ameliorated spleen and thymus damage and hematopoiesis suppression in cyclophosphamide-induced immunosuppressed mice by promoting T-cell proliferation to resist oxidative stress. In vitro, T-155 induced immature dendritic cells (DCs) to differentiate into mature DCs by the ERK1/2 pathway and converted M0 macrophages (Mφ) into the M1 type by the NF-κB pathway to enhance the surveillance capabilities of antigen-presenting cells. The experimental results suggest that T-155 has therapeutic potential as an immunomodulator for immunosuppression.

NF-κB p65 and SETDB1 expedite lipopolysaccharide-induced intestinal inflammation in mice by inducing IRF7/NLR-dependent macrophage M1 polarization

Macrophages exhibit distinct phenotypes that are pro-inflammatory (M1) or anti-inflammatory (M2) in response to inflammation. In this study, we tried to identify the roles and mechanisms of interferon regulatory factor 7 (IRF7) in modulating the phenotypes of macrophages in lipopolysaccharide (LPS)-induced intestinal inflammation. The mouse model of intestinal inflammation was induced by lipopolysaccharide (LPS), and mouse bone marrow-derived macrophages (BMDMs) and mouse intestinal epithelial cells were selected for experimental verification in vitro. Results demonstrated that IRF7 was highly expressed in the mouse model of intestinal inflammation, while IRF7 deficiency repressed macrophage M1 polarization and attenuated intestinal inflammation in mice. p65 and SET domain bifurcated 1 (SETDB1) synergistically promoted histone 3 lysine 4 trimethylation (H3K4me3) methylation to elevate IRF7 expression, which activated the Nod-like receptor (NLR) pathway to induce macrophage M1 polarization. Through this mechanism, IRF7 in BMDMs functioned to accelerate intestinal epithelial cell apoptosis and their release of pro-inflammatory proteins. Furthermore, the promoting effect of p65 and SETDB1 on LPS-induced intestinal inflammation was validated in vivo. To sum up, NF-κB p65 and SETDB1 facilitated IRF7-mediated macrophage M1 polarization, thereby aggravating the LPS-induced intestinal inflammation. Hence, this study highlights the appealing value of these factors as anti-inflammatory targets.

The gut–liver axis in sepsis: interaction mechanisms and therapeutic potential

Sepsis is a potentially fatal condition caused by dysregulation of the body's immune response to an infection. Sepsis-induced liver injury is considered a strong independent prognosticator of death in the critical care unit, and there is anatomic and accumulating epidemiologic evidence that demonstrates intimate cross talk between the gut and the liver. Intestinal barrier disruption and gut microbiota dysbiosis during sepsis result in translocation of intestinal pathogen-associated molecular patterns and damage-associated molecular patterns into the liver and systemic circulation. The liver is essential for regulating immune defense during systemic infections via mechanisms such as bacterial clearance, lipopolysaccharide detoxification, cytokine and acute-phase protein release, and inflammation metabolic regulation. When an inappropriate immune response or overwhelming inflammation occurs in the liver, the impaired capacity for pathogen clearance and hepatic metabolic disturbance can result in further impairment of the intestinal barrier and increased disruption of the composition and diversity of the gut microbiota. Therefore, interaction between the gut and liver is a potential therapeutic target. This review outlines the intimate gut–liver cross talk (gut–liver axis) in sepsis.

High Molecular Weight Fucoidan Restores Intestinal Integrity by Regulating Inflammation and Tight Junction Loss Induced by Methylglyoxal-Derived Hydroimidazolone-1

Fucoidan from brown seaweeds has several biological effects, including preserving intestinal integrity. To investigate the intestinal protective properties of high molecular weight fucoidan (HMWF) from Undaria pinnatifida on intestinal integrity dysfunction caused by methylglyoxal-derived hydroimidazolone-1 (MG-H1), one of the dietary advanced-glycation end products (dAGEs) in the human-colon carcinoma-cell line (Caco-2) cells and ICR mice. According to research, dAGEs may damage the intestinal barrier by increasing gut permeability. The findings of the study showed that HMWF + MG-H1 treatment reduced by 16.8% the amount of reactive oxygen species generated by MG-H1 treatment alone. Furthermore, HMWF + MGH-1 treatment reduced MG-H1-induced monolayer integrity disruption, as measured by alterations in transepithelial electrical resistance (135% vs. 75.5%) and fluorescein isothiocyanate incorporation (1.40 × 10^-6 cm/s vs. 3.80 cm/s). HMWF treatment prevented the MG-H1-induced expression of tight junction markers, including zonula occludens-1, occludin, and claudin-1 in Caco-2 cells and mouse colon tissues at the mRNA and protein level. Also, in Caco-2 and MG-H1-treated mice, HMWF plays an important role in preventing receptor for AGEs (RAGE)-mediated intestinal damage. In addition, HMWF inhibited the nuclear factor kappa B activation and its target genes leading to intestinal inflammation. These findings suggest that HMWF with price competitiveness could play an important role in preventing AGEs-induced intestinal barrier dysfunction.

Enhancing arginase 2 expression using target site blockers as a strategy to modulate macrophage phenotype

Macrophages are plastic cells playing a crucial role in innate immunity. While fundamental in responding to infections, when persistently maintained in a pro-inflammatory state they can initiate and sustain inflammatory diseases. Therefore, a strategy that reprograms pro-inflammatory macrophages toward an anti-inflammatory phenotype could hold therapeutic potential in that context. We have recently shown that arginase 2 (Arg2), a mitochondrial enzyme involved in arginine metabolism, promotes the resolution of inflammation in macrophages and it is targeted by miR-155. Here, we designed and tested a target site blocker (TSB) that specifically interferes and blocks the interaction between miR-155 and Arg2 mRNA, leading to Arg2 increased expression and activity. In bone marrow-derived macrophages transfected with Arg2 TSB (in the presence or absence of the pro-inflammatory stimulus LPS), we observed an overall shift of the polarization status of macrophages toward an anti-inflammatory phenotype, as shown by significant changes in surface markers (CD80 and CD71), metabolic parameters (mitochondrial oxidative phosphorylation) and cytokines secretion (IL-1β, IL-6, and TNF). Moreover, in an in vivo model of LPS-induced acute inflammation, intraperitoneal administration of Arg2 TSB led to an overall decrease in systemic levels of pro-inflammatory cytokines. Overall, this proof-of-concept strategy represent a promising approach to modulating macrophage phenotype.

Expression of MicroRNAs in Sepsis-Related Organ Dysfunction: A Systematic Review

Sepsis is a critical condition characterized by increased levels of pro-inflammatory cytokines and proliferating cells such as neutrophils and macrophages in response to microbial pathogens. Such processes lead to an abnormal inflammatory response and multi-organ failure. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of gene regulation. This means that miRNAs are involved in multiple intracellular pathways and thus contribute to or inhibit inflammation. As a result, their variable expression in different tissues and organs may play a key role in regulating the pathophysiological events of sepsis. Thanks to this property, miRNAs may serve as potential diagnostic and prognostic biomarkers in such life-threatening events. In this narrative review, we collect the results of recent studies on the expression of miRNAs in heart, blood, lung, liver, brain, and kidney during sepsis and the molecular processes in which they are involved. In reviewing the literature, we find at least 122 miRNAs and signaling pathways involved in sepsis-related organ dysfunction. This may help clinicians to detect, prevent, and treat sepsis-related organ failures early, although further studies are needed to deepen the knowledge of their potential contribution.

Modes of action and diagnostic value of miRNAs in sepsis

Sepsis is a clinical syndrome defined as a dysregulated host response to infection resulting in life-threatening organ dysfunction. Sepsis is a major public health concern associated with one in five deaths worldwide. Sepsis is characterized by unbalanced inflammation and profound and sustained immunosuppression, increasing patient susceptibility to secondary infections and mortality. microRNAs (miRNAs) play a central role in the control of many biological processes, and deregulation of their expression has been linked to the development of oncological, cardiovascular, neurodegenerative and metabolic diseases. In this review, we discuss the role of miRNAs in sepsis pathophysiology. Overall, miRNAs are seen as promising biomarkers, and it has been proposed to develop miRNA-based therapies for sepsis. Yet, the picture is not so straightforward because of the versatile and dynamic features of miRNAs. Clearly, more research is needed to clarify the expression and role of miRNAs in sepsis, and to promote the use of miRNAs for sepsis management.

Exploration of the molecular mechanisms, shared gene signatures, and MicroRNAs between systemic lupus erythematosus and diffuse large B cell lymphoma by bioinformatics analysis

BACKGROUND

Systemic lupus erythematosus (SLE) is a complex heterogeneous systemic autoimmune disease. Previous studies have shown that SLE may be related to diffuse large B cell lymphoma (DLBCL), but the mechanism of their relationship is still unclear. The present study aimed to explore the common genetic molecular mechanisms, core shared genes, and miRNAs between SLE and DLBCL as well as to investigate the diagnostic markers of DLBCL.

METHODS

The SLE and DLBCL microarray data were downloaded from the comprehensive Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was used to identify co-expression modules. Four core shared genes were screened out by various algorithms and validated in other cohorts. Finally, we constructed a common core gene-miRNA network using the human microRNA disease database (HMDD) and TarBase.

RESULTS

Using WGCNA, four modules were identified as important modules for SLE and DLBCL. Enrichment analysis of the shared genes showed that the highly activated NF-κB pathway was a common feature of the pathophysiology. Four core shared genes, namely, PSMB10, PSMB4, TAF10, and NFΚBIA, were screened out. These core shared genes were significantly upregulated in both diseases, and they may be potential diagnostic markers of DLBCL. The core gene-miRNA network showed that miR-155-5p, regulating the shared NF-κB pathway, may play an important role in the susceptibility of SLE patients to DLBCL.

CONCLUSION

The present study revealed that NF-κB pathway in SLE may be a crucial susceptible factor for DLBCL. In addition, we identified PSMB10, PSMB4, TAF10, NFΚBIA and miR-155 involved in the common pathogenesis as potential biomarkers and therapeutic targets for DLBCL.

The NF-κB-regulated miR-221/222/syndecan-1 axis restores intestinal mucosal barrier function in radiation enteritis

PURPOSE

Radiation enteritis (RE) is the most common complication of pelvic radiotherapy, but proven therapies are lacking. Barrier function defects are closely associated with numerous inflammatory disorders. In this study, we investigated whether barrier dysfunction contributes to RE and whether syndecan-1 (Sdc1) protects intestinal barrier function in RE. The mechanism was also elucidated.

MATERIALS AND METHODS

Blood, urine, and tissue samples were collected from 21 patients with cervical cancer who experienced RE during radiotherapy and used to detect inflammatory responses and barrier function. The role of Sdc1 in barrier function was examined in cultured fetal human colon (FHC) cells exposed to radiation and an induced mouse RE model. Barrier function was determined by zonula occludens (ZO)-1 and occludin expression, transepithelial electrical resistance (TEER), and FITC-dextran (FD4) flux. The role of the nuclear factor (NF)-κB-P65 pathway was detected by Western blotting and chromatin immunoprecipitation. The role of miR-221/222 was assessed by real-time PCR and luciferase reporter assays.

RESULTS

Patients with RE exhibited obvious pathological and ultra-microstructural inflammatory injury and barrier disruption in the intestinal mucosa, as well as higher serum lipopolysaccharide (LPS), LPS-binding protein, and cytokine levels and a higher urine lactulose/mannitol ratio. Sdc1 overexpression in irradiated FHC cells reversed TEER suppression, repressed FD4 flux, and upregulated ZO-1 and occludin expression. Exogenous low-molecular-weight heparin supplementation in RE mice ameliorated the activity of enteritis and barrier defects. Mechanistically, irradiation-activated P65 increased the transcription of miR-221/222 via direct binding to their promoter regions, and miR-221/222 then post-transcriptionally suppressed the Sdc1 gene by binding to its 3'-untranslated region.

CONCLUSIONS

Sdc1 protects barrier function and controls inflammation during RE under transcriptional regulation by the NF-κB pathway and miR-221/222. The network including NF-κB, miR-221/222, and Sdc1 is important in the pathogenesis of RE. Sdc1 might represent a therapeutic target for novel anti-RE strategies.

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.

Detecting Critical Functional Ingredients Group and Mechanism of Xuebijing Injection in Treating Sepsis

Sepsis is a systemic inflammatory reaction caused by various infectious or noninfectious factors, which can lead to shock, multiple organ dysfunction syndrome, and death. It is one of the common complications and a main cause of death in critically ill patients. At present, the treatments of sepsis are mainly focused on the controlling of inflammatory response and reduction of various organ function damage, including anti-infection, hormones, mechanical ventilation, nutritional support, and traditional Chinese medicine (TCM). Among them, Xuebijing injection (XBJI) is an important derivative of TCM, which is widely used in clinical research. However, the molecular mechanism of XBJI on sepsis is still not clear. The mechanism of treatment of "bacteria, poison and inflammation" and the effects of multi-ingredient, multi-target, and multi-pathway have still not been clarified. For solving this issue, we designed a new systems pharmacology strategy which combines target genes of XBJI and the pathogenetic genes of sepsis to construct functional response space (FRS). The key response proteins in the FRS were determined by using a novel node importance calculation method and were condensed by a dynamic programming strategy to conduct the critical functional ingredients group (CFIG). The results showed that enriched pathways of key response proteins selected from FRS could cover 95.83% of the enriched pathways of reference targets, which were defined as the intersections of ingredient targets and pathogenetic genes. The targets of the optimized CFIG with 60 ingredients could be enriched into 182 pathways which covered 81.58% of 152 pathways of 1,606 pathogenetic genes. The prediction of CFIG targets showed that the CFIG of XBJI could affect sepsis synergistically through genes such as TAK1, TNF-α, IL-1β, and MEK1 in the pathways of MAPK, NF-κB, PI3K-AKT, Toll-like receptor, and tumor necrosis factor signaling. Finally, the effects of apigenin, baicalein, and luteolin were evaluated by in vitro experiments and were proved to be effective in reducing the production of intracellular reactive oxygen species in lipopolysaccharide-stimulated RAW264.7 cells, significantly. These results indicate that the novel integrative model can promote reliability and accuracy on depicting the CFIGs in XBJI and figure out a methodological coordinate for simplicity, mechanism analysis, and secondary development of formulas in TCM.

MiR-140 suppresses airway inflammation and inhibits bronchial epithelial cell apoptosis in asthma by targeting GSK3β

AIM OF THE STUDY

Asthma is a common and complex chronic inflammatory disease induced by genetic and environmental factors that affects the airways of the lungs. MicroRNAs (miRNAs) are key regulators of various cellular processes and have been shown to be critically involved in asthma progression. The objective of our study was to clarify the function and molecular mechanism of miR-140 in the progression of asthma.

MATERIALS AND METHODS

MiR-140 expression was evaluated using RT-qPCR. Pathological changes in the lung tissue were confirmed using HE and PAS staining. The levels of IL-5, TGF-β1, and IL-13 in the serum or bronchioalveolar lavage fluid were detected with an ELISA. Cellular apoptosis was measured using a TUNEL assay. The levels of Bax, Bcl-2, Cleaved caspase-3, and glycogen synthase kinase-3β (GSK-3β) were verified with a western blot. GSK3β expression was also confirmed by immunohistochemistry. The binding ability between miR-140 and GSK3β was confirmed using a luciferase reporter assay, RNA immunoprecipitation (RIP) assay and Pull-down assay.

RESULTS

MiR-140 was markedly downregulated in asthmatic mice. Additionally, miR-140 weakened airway inflammation and bronchial epithelial cell apoptosis in asthmatic mice. Further experiments revealed that miR-140 negatively regulated GSK3β expression and could bind to GSK3β in asthma. Finally, rescue assays demonstrated that GSK3β overexpression rescued the effects of miR-140 on asthma progression.

CONCLUSION

MiR-140 targeted GSK3β to suppress airway inflammation and inhibit bronchial epithelial cell apoptosis in asthma.

Sepsis induces muscle atrophy by inhibiting proliferation and promoting apoptosis via PLK1-AKT signalling

Sepsis and sepsis-induced skeletal muscle atrophy are common in patients in intensive care units with high mortality, while the mechanisms are controversial and complicated. In the present study, the atrophy of skeletal muscle was evaluated in sepsis mouse model as well as the apoptosis of muscle fibres. Sepsis induced atrophy of skeletal muscle and apoptosis of myofibres in vivo and in vitro. In cell-based in vitro experiments, lipopolysaccharide (LPS) stimulation also inhibited the proliferation of myoblasts. At the molecular level, the expression of polo-like kinase 1 (PLK1) and phosphorylated protein kinase B (p-AKT) was decreased. Overexpression of PLK1 partly rescued LPS-induced apoptosis, proliferation suppression and atrophy in C2C12 cells. Furthermore, inhibiting the AKT pathway deteriorated LPS-induced atrophy in PLK1-overexpressing C2C12 myotubes. PLK1 was found to participate in regulating apoptosis and E3 ubiquitin ligase activity in C2C12 cells. Taken together, these results indicate that sepsis induces skeletal muscle atrophy by promoting apoptosis of muscle fibres and inhibiting proliferation of myoblasts via regulation of the PLK1-AKT pathway. These findings enhance understanding of the mechanism of sepsis-induced skeletal muscle atrophy.

Imidacloprid increases intestinal permeability by disrupting tight junctions

The neonicotinoid pesticide, imidacloprid (IMI), is frequently detected in the environment and in foods. It is absorbed and metabolized by the intestine; however, its effects on intestinal barrier integrity are not well studied. We investigated whether IMI disrupts the permeability of the intestinal epithelial barrier via in vivo tests on male Wistar rats, in vitro assays using the human intestinal epithelial cell line, Caco-2, and in silico analyses. A repeated oral dose 90-day toxicity study was performed (0.06 mg/kg body weight/day). IMI exposure significantly increased intestinal permeability, which led to significantly elevated serum levels of endotoxin and inflammatory biomarkers (tumor necrosis factor-alpha and interleukin-1 beta) without any variation in body weight. Decreased transepithelial electrical resistance with increased permeability was also observed in 100 nM and 100 μM IMI-treated Caco-2 cell monolayers. Amounts of tight junction proteins in IMI-treated colon tissues and between IMI-treated Caco-2 cells were significantly lower than those of controls. Increased levels of myosin light chain phosphorylation, myosin light chain kinase (MLCK), and p65 subunit of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB p65) phosphorylation were found in IMI-exposed cells compared with control cells. Furthermore, the barrier loss caused by IMI was rescued by the MLCK inhibitor, ML-7, and cycloheximide. Pregnane X receptor (PXR, NR1I2) was inhibited by low-dose IMI treatment. In silico analysis indicated potent binding sites between PXR and IMI. Together, these data illustrate that IMI induces intestinal epithelial barrier disruption and produces an inflammatory response, involving the down-regulation of tight junctions and disturbance of the PXR-NF-κB p65-MLCK signaling pathway. The intestinal barrier disruption caused by IMI deserves attention in assessing the safety of this neonicotinoid pesticide.

Sepsis induces variation of intestinal barrier function in different phase through nuclear factor kappa B signaling

The intestinal barrier function disrupted in sepsis, while little is known about the variation in different phases of sepsis. In this study, mouse models of sepsis were established by caecal ligation and puncture (CLP). The H&E staining of sections and serum diamine oxidase concentration were evaluated at different timepoint after CLP. TUNEL assay and EdU staining were performed to evaluate the apoptosis and proliferation of intestinal epithelium. Relative protein expression was assessed by Western blotting and serum concentrations of pro-inflammatory cytokines was measured by ELISA. The disruption of intestinal barrier worsened in the first 24 h after the onset of sepsis and gradually recovered over the next 24 h. The percentage of apoptotic cell increased in the first 24 h and dropped at 48 h, accompanied with the proliferative rate of intestinal epithelium inhibited in the first 6 h and regained in the later period. Furthermore, the activity of nuclear factor kappa B (NF-κB) presented similar trend with the intestinal barrier function, shared positive correction with apoptosis of intestinal epithelium. These findings reveal the conversion process of intestinal barrier function in sepsis and this process is closely correlated with the activity of NF-κB signaling.