Baicalin promotes antibacterial defenses by modulating mitochondrial function.

Natural flavonoids, such as baicalin, have been extensively studied for their role in bacterial infection. However, the underlying mechanisms remain poorly understood. We demonstrated that baicalin coordinates mitochondrial function and dynamics to promote antibacterial response. Baicalin protected against Staphylococcus aureus infections and alleviates inflammatory responses in vivo and in vitro. An increase in mitochondrial mass and elevated expression of factors regulating mitochondrial fission and fusion were observed in baicalin-treated macrophages. Baicalin induced Drp1-dependent biogenesis, which contributes to the generation of additional mitochondria. Baicalin improved the mitochondrial membrane potential, ATP levels, and mitochondrial reactive oxygen species (mtROS) production. Importantly, the inhibition of mitochondrial function by rotenone or MitoTEMPO suppressed the antimicrobial activity of baicalin in macrophages. We conclude that baicalin can regulate immune responses during S. aureus infection by improving mitochondrial function and dynamics, implying that it is a promising therapeutic agent for controlling infection and inflammatory diseases.

CD200 Modulates S. aureus-Induced Innate Immune Responses Through Suppressing p38 Signaling.

Rapid activation of macrophages plays a central role in eliminating invading bacteria as well as in triggering the inflammatory responses, but how the anti-bacterial and the inflammatory responses are coordinated, in terms of macrophages, is not completely understood. In this study, we demonstrated that Staphylococcus aureus (S. aureus) induced the expression of CD200 in murine macrophages in a dose-dependent manner. We found that CD200 significantly suppressed the S. aureus-induced production of nitric oxide and proinflammatory cytokines in mouse macrophages. Concurrently, the bactericidal capability of macrophages was boosted upon the deletion of CD200. Furthermore, our data demonstrated that p38 mitogen-activated protein kinase (MAPK) was selectively down-regulated by CD200 administration, while enhanced upon CD200 silence in response to staphylococcal infection. The negative effect of CD200 siRNA on NO production in macrophages was largely abrogated upon the inhibition of p38 signaling, implying its critical involvement in this regulation. Together, our data demonstrate that CD200 plays a central role in regulating the inflammatory responses and the anti-bacterial activity of macrophages, at least partially, through suppressing p38 activity.

MiR-127 modulates macrophage polarization and promotes lung inflammation and injury by activating the JNK pathway.

A polarized macrophage response is presumed to have a pivotal role in a variety of immunological pathophysiology. However, the molecular mechanism underlying macrophage functional shaping remains largely unknown. In this study, we reveal a pivotal role of miR-127 in macrophage development and thereby the pathogenesis of inflammation and lung injury. In particular, miR-127 was demonstrated to be prominently induced upon TLR engagement and repressed by the M2-prone cytokines. Enforced expression of miR-127 in macrophages resulted in significantly increased production of proinflammatory cytokines, whereas deletion of miR-127 impaired M1 gene expression and led to a M2-biased response. Accordingly, intratracheal administration of miR-127 resulted in an exaggerated pulmonary inflammation and injury. Conversely, antagonizing of miR-127 suppressed production of the proinflammatory cytokines and rendered the mice more refractory to the inflammation-associated pathology. Mechanistically, miR-127 demonstrated to target B cell lymphoma 6 (Bcl6) and remarkably downregulated its expression and subsequently dual specificity phosphatase 1 (Dusp1), which in turn enhanced the activation of JNK kinase and hence the development of proinflammatory macrophages. Thereby, reconstitution with the expression of Bcl6 or Dusp1 or inhibition of JNK activity impaired miR-127-mediated skewing of M1 proinflammatory macrophages, whereas interference of Bcl6 or Dusp1 expression abrogated the anti-inflammatory property of anti-miR-127. Together, these data establish miR-127 as a molecular switch during macrophage development and as a potential target for treatment of inflammatory diseases.

MiR-221 activates the NF-κB pathway by targeting A20.

MicroRNAs play an important role in regulating the inflammatory response, and are critically involved in the development of inflammatory disorders, including those affecting the lungs. While the microRNA miR-221 is involved in embryonic lung branching morphogenesis and epithelial cell development, its importance in lung inflammation has not been previously explored. In our current study, expression of miR-221 was selectively decreased by exposure to lipopolysaccharides (LPS) both in vitro and in vivo. Enforced expression of miR-221 significantly increased the production of proinflammatory cytokines TNF-α and IL-6, and enhanced the activation of NF-κB and MAPKs upon LPS stimulation. Accordingly, intratracheal stimulation of miR-221 was shown to aggravate endotoxin-induced acute lung injuries and inflammation in mice. Mechanistic studies showed that miR-221 directly targets A20, a master regulator of NF-κB and MAPK signaling, and thus represses inflammatory signaling. Restoration of A20 in macrophages abolished the stimulatory effect of miR-221 on production of proinflammatory cytokines. Together, these results indicate the presence of a novel miRNA-mediated feed-back mechanism that controls inflammation, and suggest involvement of aberrant miR-221 expression in the development of inflammatory lung disorders.

MEK1/2 inhibitors induce interleukin-5 expression in mouse macrophages and lymphocytes.

Uptake of oxidized low-density lipoprotein (oxLDL) by macrophages facilitates the formation of foam cells, the prominent part of atherosclerotic lesions. Interleukin-5 (IL-5) is a cytokine regulating interactions between immune cells. It also activates the production of T15/EO6 IgM antibodies in B-1 cells, which can bind oxLDL thereby demonstrating anti-atherogenic properties. We previously reported that inhibition of extracellular signal-regulated kinases 1 and 2 (ERK1/2) by mitogen-activated protein kinase kinases 1/2 (MEK1/2) inhibitors can reduce atherosclerosis. In this study, we determined the effects of MEK1/2 inhibitors on IL-5 production both in vitro and in vivo. In vitro, MEK1/2 inhibitors (PD98059 and U0126) substantially inhibited phosphorylation of MEK1/2 and ERK1/2. Associated with inhibition of ERK1/2 phosphorylation both in vitro and in vivo, MEK1/2 inhibitors induced IL-5 protein expression in macrophages (RAW macrophages and peritoneal macrophages) and lymphocytes (EL-4 cells). In vivo, administration of mice with MEK1/2 inhibitors increased serum IL-5 levels, and IL-5 protein expression in mouse spleen and liver. At the mechanistic level, we determined that MEK1/2 inhibitors activated IL-5 mRNA expression and IL-5 promoter activity in the liver X receptor (LXR) dependent manner indicating the induction of IL-5 transcription. In addition, we determined that MEK1/2 inhibitors enhanced IL-5 protein stability. Taken together, our study demonstrates that MEK1/2 inhibitors induce IL-5 production which suggests another anti-atherogenic mechanism of MEK1/2 inhibitors.

MAPK kinase 3 potentiates Chlamydia HSP60-induced inflammatory response through distinct activation of NF-κB.

Chlamydia pneumonia (C. pneumonia) remains one of the leading causes of bacterial pneumonia and has been implicated in the pathogenesis of some inflammation-related diseases, such as asthma, chronic obstructive pulmonary disease, and vascular diseases. Heat shock protein 60 is one of the pathogenic components of C. pneumonia that is closely associated with the inflammatory disorders. However, the molecular basis for the immunopathologic property of chlamydial heat shock protein (cHSP60) has not been elucidated. In this article, we report that MAPK kinase 3 (MKK3) is essential for cHSP60-induced lung inflammation, because MKK3-knockout mice displayed significantly reduced lung neutrophil accumulation and decreased production of proinflammatory mediators, correlating with the alleviated inflammatory response in lung tissues. Mechanistically, p38 kinase was selectively activated by MKK3 in response to cHSP60 and activated NF-κB by stimulating the nuclear kinase, mitogen- and stress-activated protein kinase 1. The specific knockdown of mitogen- and stress-activated protein kinase 1 in macrophages resulted in a defective phosphorylation of NF-κB/RelA at Ser(276) but had no apparent effect on RelA translocation. Furthermore, TGF-ß-activated kinase 1 was found to relay the signal to MKK3 from TLR4, the major receptor that sensed cHSP60 in the initiation of the inflammatory response. Thus, we establish a critical role for MKK3 signaling in cHSP60 pathology and suggest a novel mechanism underlying C. pneumonia-associated inflammatory disorders.

Akt1-mediated regulation of macrophage polarization in a murine model of Staphylococcus aureus pulmonary infection.

Macrophage polarization is critical for dictating host defense against pathogens and injurious agents. Dysregulation of macrophage differentiation has been implicated in infectious and inflammatory diseases. Here, we show that protein kinase B/Akt1 signaling induced by Staphylococcus aureus is essential in shifting macrophages from an antimicrobial phenotype (M1) to a functionally inert signature. Akt1(-/-)mice consistently had enhanced bacterial clearance and greater survival, compared with their wild-type littermates. The blunted M1 macrophage reaction driven by Akt1 was associated with decreased RelA/nuclear factor κB activity. Furthermore, by repression of the expression of suppressor of cytokine signaling 1 (SOCS1), microRNA 155 revealed to promote the transcription of M1 signature genes in macrophages from Akt1(-/-) mice. Accordingly, blocking of microRNA 155 in macrophages from Akt1(-/-)mice or knockdown of SOCS1 in cells from wild-type mice disabled or enabled, respectively, an M1 macrophage shift and antibacterial response. These results thus establish an Akt1-mediated, microRNA-involved circuit that regulates pathogen-driven macrophage polarization and, subsequently, the host response to infection.

Characterization and potential lipid-lowering effects of lactic acid bacteria isolated from cats.

Introduction: This study aimed to study the characterization and the potential lipid-lowering effects of new isolated lactic acid bacteria from the feces of healthy adult cats. Methods: We collected 85 cat fecal samples, isolated, screening lactic acid bacteria strains from samples, and investigated their in vitro and in vivo biological properties. Results: A total of 221 lactic acid bacteria strains were isolated from 85 cat fecal samples. Sixteen strains with calcium dissolution rings greater than 1 mm were identified and selected for further characterization. Three lactic acid bacteria strains, Lactobacillus plantarum L-27-2, Pediococcus lactis L-14-1, and Enterococcus faecium, were identified as showing the most promising rates of cholesterol degradation (greater than 20%) and bacteriostatic radius (over 15 mm). These three strains exhibited robust growth and adherence to epithelial cells, along with adaptability to low pH (greater than 70%) and high bile salt conditions (greater than 60%), and remarkable cholesterol degradation and anti-pathogen activity. Sixteen mice were fed a high-fat diet (HFD) from 4 to 8 weeks of age, while a control group of the same size received a normal diet (ND). At 8 weeks of age, serum, feces and adipose tissue were collected. The results showed that, compared with mice fed an HFD diet alone, all mice fed an HFD diet plus lactic acid bacteria could decrease weight gain. P < 0.05 and the pathological changes of adipose tissue were alleviated. In addition, mice fed L-14-1 and F203 showed abdominal fat accumulation decreased (P < 0.05). Mice fed L-27-2 showed serum and liver triglyceride (TG) decreased (P < 0.05) and mice fed F203 showed serum high density lipoprotein cholesterol (HDL-C) increased (P < 0.01). mice fed L-27-2 and L-14-1 showed inflammatory cytokines (IL-6) was decreased (P < 0.01) Analysis of the fecal microbiota of mice fed these three lactic acid bacteria strains revealed alterations in the gut microbial community. There were common changes in intestinal microbes in mice fed these three lactic acid bacteria: (1) Bacteroides decreased; (2) Myxococcus increased; (3) Lachnoclostridium decreased. The microbes mentioned are all part of the core intestinal flora. Discussion: This study provided three potential lactic acid bacteria for alleviating animal obesity and inflammation.

Adaptive attenuation of virulence in hypervirulent carbapenem-resistant Klebsiella pneumoniae.

The emergence of nosocomial infections caused by hypervirulent and carbapenem-resistant K. pneumoniae (hv-CRKP) has become a significant public health challenge. The genetic traits of virulence and resistance plasmids in hv-CRKP have been extensively studied; however, research on the adaptive evolution strategies of clinical strains inside the host was scarce. This study aimed to understand the effects of antibiotic treatment on the phenotype and genotype characteristics of hv-CRKP. We investigated the evolution of hv-CRKP strains isolated from the same patient to elucidate the transition between hospital invasion and colonization. A comparative genomics analysis was performed to identify single nucleotide polymorphisms in the rmpA promoter. Subsequent validation through RNA-seq and gene deletion confirmed that distinct rmpA promoter sequences exert control over the mucoid phenotype. Additionally, biofilm experiments, cell adhesion assays, and animal infection models were conducted to illuminate the influence of rmpA promoter diversity on virulence changes. We demonstrated that the P12T and P11T promoters of rmpA possess strong activity, which leads to the evolution of CRKP into infectious and virulent strains. Meanwhile, the specific sequence of polyT motifs in the rmpA promoter led to a decrease in the lethality of hv-CRKP and enhanced cell adhesion and colonization. To summarize, the rmpA promoter of hv-CRKP is utilized to control capsule production, thereby modifying pathogenicity to better suit the host's ecological environment.IMPORTANCEThe prevalence of hospital-acquired illness caused by hypervirulent carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) is significant, leading to prolonged antibiotic treatment. However, there are few reports on the phenotypic changes of hv-CRKP in patients undergoing antibiotic treatment. We performed a comprehensive examination of the genetic evolutionary traits of hv-CRKP obtained from the same patient and observed variations in the promoter sequences of the virulence factor rmpA. The strong activity of the promoter sequences P11T and P12T enhances the consistent production of capsule polysaccharides, resulting in an invasive strain. Conversely, weak promoter activity of P9T and P10T is advantageous for exposing pili, hence improving bacterial cell attachment ability and facilitating bacterial colonization. This finding also explains the confusion of some clinical strains carrying wild-type rmpA but exhibiting a low mucoid phenotype. This adaptive alteration facilitates the dissemination of K. pneumoniae within the hospital setting.

Activation of liver X receptor induces macrophage interleukin-5 expression.

IL-5 stimulates production of T15/EO6 IgM antibodies that can block the uptake of oxidized low density lipoprotein by macrophages, whereas a deficiency in macrophage IL-5 expression accelerates development of atherosclerosis. Liver X receptors (LXRs) are ligand-activated transcription factors that can induce macrophage ABCA1 expression and cholesterol efflux, thereby inhibiting the development of atherosclerosis. However, it remains unknown whether additional mechanisms, such as the regulation of macrophage IL-5 expression, are related to the anti-atherogenic properties of LXR. We initially defined IL-5 expression in macrophages where the LXR ligand (T0901317) induced macrophage IL-5 protein expression and secretion. The overexpression of LXR increased, whereas its knockdown inhibited IL-5 expression. Furthermore, we found that LXR activation increased IL-5 transcripts, promoter activity, formation of an LXR·LXR-responsive element complex, and IL-5 protein stability. In vivo, we found that T0901317 increased IL-5 and total IgM levels in plasma and IL-5 expression in multiple tissues in wild type mice. In LDL receptor knock-out (LDLR(-/-)) mice, T0901317 increased IL-5 expression in the aortic root area. Taken together, our studies demonstrate that macrophage IL-5 is a target gene for LXR activation, and the induction of macrophage IL-5 expression can be related to LXR-inhibited atherosclerosis.

Targeting of Rho kinase ameliorates impairment of diabetic endothelial function in intrarenal artery.

Endothelial dysfunction in kidney vasculature is the initial and key element for nephropathy in diabetes mellitus. Accumulating evidence suggests the protective role of Rho kinase inhibitors in endothelial dysfunction via modulating eNOS activity and NO production. However, the role of Rho kinase in diabetes-related endothelial dysfunction in kidney vasculature and the relevant mechanisms remain unknown. We assessed whether pharmacological inhibition of Rho kinase attenuates endothelial dysfunction in intrarenal arteries from type 1 diabetic rats. Fasudil, a Rho kinase inhibitor effectively decreased the phosphorylated level of MYPT1 without affecting the expression of ROCKs in the kidney. Fasudil treatment showed no improvement in diabetes-related abnormality in metabolic indices, but it significantly ameliorated endothelial dysfunction in intrarenal arteries and lessened the mesangial matrix expansion in the kidney cortex. Mechanistically, superoxide production in the intrarenal artery and NOX4 member of NADPH oxidase in the renal cortex that contribute to diabetic nephropathy were also prevented by the Rho kinase inhibitor. In conclusion, the present results indicate that Rho kinase is involved in endothelial dysfunction in type 1 diabetes via enhancement of oxidative stress and provides new evidence for Rho kinase inhibitors as potential therapeutic agents for the treatment of diabetic nephropathy.

The potential role of methyltransferase-like 5 in deficient mismatch repair of uterine corpus endometrial carcinoma.

To explore the potential function of methyltransferase-like 5 (METTL5) in uterine corpus endometrial carcinoma (UCEC) and verify the relationship between deficient DNA mismatch repair (MMR) and METTL5. We used bioinformatics to predict the possible role of METTL5 and molecular biology methods to analyze METTL5 expression. We observed UCEC proliferation, development, and apoptosis using a METTL5 knockdown lentivirus and, coupled with METTL5 bioinformatics and Western blot analysis, detected microsatellite instability (MSI) and MMR. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. Finally, some METTL5-associated gene mutations in UCECs were detected. Results show that METTL5 expression in UCEC tumor tissue was increased, and UCEC patients with high METTL5 expression had worse prognostic outcomes. We also observed the highest METTL5 expression level in KLE cells. Furthermore, knocking down METTL5 weakened the proliferation, reduced tumor volume and biomarkers, and increased apoptosis. Moreover, METTL5 knockdown induced the MSH2, MSH6 and PMS2 expression in MMR. METTL5 was negatively correlated with gene silencing, mRNA binding, olfactory receptor activity, antigen processing and presentation, cytosolic DNA sensing, olfactory transduction, and RIG-1-like and Toll-like receptor signaling pathways. METTL5 may regulate MMR protein levels in UCECs, thus enhancing UCEC proliferation, development, and prognosis.

Dysfunctional telomeres through mitostress-induced cGAS/STING activation to aggravate immune senescence and viral pneumonia.

Disproportionately high incidence and mortality of respiratory infection such as influenza A virus (IAV) and SARS-CoV-2 have been evidenced in the elderly, but the role and the mechanism of age-associated immune deregulation in disease exacerbation are not well defined. Using a late generation of mice deficient in telomerase RNA (Terc-/- ), we herein demonstrated that aged mice were exquisitely susceptible to respiratory viral infection, with excessive inflammation and increased mortality. Furthermore, we identified the cGAS/STING pathway, which was essentially induced by the leaked mitochondrial DNA, as a biologically relevant mechanism contributing to exaggerated inflammation in Terc-/- mice following viral infection. Innate immune cells, mainly, macrophages with shortened telomeres, exhibited hallmarks of cellular senescence, mitochondrial distress, and aberrant activation of STING and NLRP3 inflammasome pathways, which predisposed mice to severe viral pneumonia during commonly mild infections. Application of STING inhibitor and, more importantly, senolytic agent, reduced the burden of stressed macrophages, improved mitochondrial integrity, and suppressed STING activation, thereby conferring the protection for Terc-/- mice against respiratory infection. Together, the findings expand our understanding of innate immune senescence and reveal the potential of the senolytics as a promising treatment to alleviate the symptom of viral pneumonia, particularly for the older population.

RNA-binding protein with serine-rich domain 1 regulates microsatellite instability of uterine corpus endometrial adenocarcinoma.

OBJECTIVE: To determine the role of RNA-binding protein with serine-rich domain 1 (RNPS1) in uterine corpus endometrial carcinoma (UCEC), the role of RNPS1 knockdown in UCEC development in vitro and in vivo, and the relationship between RNPS1 and mismatch repair (MMR) in UCEC. METHODS: We predicted the potential function of RNPS1 using bioinformatics systems. The expression of RNPS1 in tissues and cell lines was analyzed by western blotting and immunohistochemistry. The expression of RNPS1 in MMR was assessed using bioinformatics and western blotting. The proliferation and apoptosis of UCEC cells were assessed under RNPS1 knockdown conditions, and RNPS1 regulation in MMR was detected by suppressing Notch signaling. Associations between RNPS1 and gene mutations in UCEC and prognosis were analyzed. RESULTS: The RNPS1 level was higher in UCEC tumors than in normal tissues and tumors or RL952 cells. Prognostic outcomes were worse when UCEC showed abundant RNPS1 expression. Lentiviral RNPS1 knockdown weakened tumor cell proliferation and suppressed biomarker expression, reduced the tumor volume, promoted apoptosis in vitro and in vivo, and inhibited UCEC development. Increased MutS homolog 2 (MSH2) and MutS homolog 6 (MSH6) levels in MMR after RNPS1 knockdown were reversed by inhibiting Notch signaling. Furthermore, RNPS1 was associated with mutations in NAA11, C2orf57, NUPR1, and other genes involved in UCEC prognosis. CONCLUSION: RNPS1 may regulate the expression levels of MSH2 and MSH6 in MMR, enhancing the proliferation, development, and prognosis of UCEC through a Notch signaling pathway in UCEC. Our study offers a new method and strategy for delaying UCEC development through modulating MMR.

Elf4 regulates lysosomal biogenesis and the mTOR pathway to promote clearance of Staphylococcus aureus in macrophages.

Staphylococcus aureus is a major cause of infectious disease. Macrophages can directly destroy most of the invading bacteria through the phagolysosomal pathway. E74-like factor 4 (Elf4) is one of the important transcription factors that controls diverse pathogens, but the role of Elf4 in macrophage-mediated S. aureus eradication is unknown. Our data show that Elf4 is induced by S. aureus in macrophages. Elevated expression of Elf4 results in decreased bacterial load and inflammatory responses during S. aureus infection in vivo and in vitro. Elf4-overexpressed macrophages have decreased mTOR activity and increased lysosomal mass. Collectively, these results suggest that S. aureus induces Elf4 expression, which enhances lysosomal function and increases the capacity of macrophages to eliminate intracellular pathogens.

miR-20a-5p inhibits endometrial cancer progression by targeting janus kinase 1.

Endometrial cancer (EC) is a multi-factorial disease of which pathogenesis has not been fully elucidated. The function and underlying mechanism of microRNA-20a-5p (miR-20a-5p) in EC remain poorly understood. The present study aimed to analyze the association between miR-20a-5p expression and the clinicopathological characteristics of patients with EC. Whether miR-20a-5p could inhibit EC progression by targeting janus kinase 1 (Jak1) was subsequently investigated. To do so, human EC tissues and paracancerous tissues were collected from 47 patients with EC. miR-20a-5p and Jak1 mRNA and protein expression was determined by reverse transcription quantitative PCR and western blotting, respectively. Cell proliferation, invasive ability and adhesion were investigated by MTT, Matrigel invasion and cell adhesion assays, respectively. Dual luciferase reporter assay was used to verify whether miR-20a-5p could directly target Jak1. The results demonstrated that miR-20a-5p was downregulated and that Jak1 was upregulated in EC tissues compared with paracancerous tissues. In addition, miR-20a-5p expression and Jak1 expression level were negatively correlated in EC tissues. miR-20a-5p expression was also significantly associated with the depth of myometrial invasion, FIGO stage, histologic grade and lymph node metastasis in patients with EC. Furthermore, Jak1 was identified as a new direct target of miR-20a-5p, and Jak1 overexpression was demonstrated to reverse the effects of miR-20a-5p-mimic on EC cell proliferation, invasive ability and adhesion. Taken together, the results from this study revealed for the first time that miR-20a-5p expression was significantly associated with the clinicopathological characteristics of patients with EC. These findings suggested that miR-20a-5p may act as a tumor suppressor in EC, in part through decreasing Jak1 expression. miR-20a-5p and Jak1 may therefore serve as potential therapeutic targets in EC.

5-Hydroxymethylfurfural Alleviates Inflammatory Lung Injury by Inhibiting Endoplasmic Reticulum Stress and NLRP3 Inflammasome Activation.

5-Hydroxymethylfurfural (5-HMF) is a common reaction product during heat processing and the preparation of many types of foods and Traditional Chinese Medicine formulations. The aim of this study was to evaluate the protective effect of 5-HMF on endotoxin-induced acute lung injury (ALI) and the underlying mechanisms. Our findings indicate that 5-HMF attenuated lipopolysaccharide (LPS)-induced ALI in mice by mitigating alveolar destruction, neutrophil infiltration and the release of inflammatory cytokines. Furthermore, the activation of macrophages and human monocytes in response to LPS was remarkably suppressed by 5-HMF in vitro through inhibiting the NF-κB signaling pathway, NLRP3 inflammasome activation and endoplasmic reticulum (ER) stress. The inhibitory effect of 5-HMF on NLRP3 inflammasome was reversed by overexpressing ATF4 or CHOP, indicating the involvement of ER stress in the negative regulation of 5-HMF on NLRP3 inflammasome-mediated inflammation. Consistent with this, the ameliorative effect of 5-HMF on in vivo pulmonary dysfunction were reversed by the ER stress inducer tunicamycin. In conclusion, our findings elucidate the anti-inflammatory and protective efficacy of 5-HMF in LPS-induced acute lung injury, and also demonstrate the key mechanism of its action against NLRP3 inflammasome-related inflammatory disorders via the inhibition of ER stress.

PP2Cδ Controls the Differentiation and Function of Dendritic Cells Through Regulating the NSD2/mTORC2/ACLY Pathway.

Dendritic cells (DCs) are recognized as a key orchestrator of immune response and homeostasis, deregulation of which may lead to autoimmunity such as experimental autoimmune encephalomyelitis (EAE). Herein we show that the phosphatase PP2Cδ played a pivotal role in regulating DC activation and function, as PP2Cδ ablation caused aberrant maturation, activation, and Th1/Th17-priming of DCs, and hence induced onset of exacerbated EAE. Mechanistically, PP2Cδ restrained the expression of the essential subunit of mTORC2, Rictor, primarily through de-phosphorylating and proteasomal degradation of the methyltransferase NSD2 via CRL4DCAF2 E3 ligase. Loss of PP2Cδ in DCs accordingly sustained activation of the Rictor/mTORC2 pathway and boosted glycolytic and mitochondrial metabolism. Consequently, ATP-citrate lyse (ACLY) was increasingly activated and catalyzed acetyl-CoA for expression of the genes compatible with hyperactivated DCs under PP2Cδ deletion. Collectively, our findings demonstrate that PP2Cδ has an essential role in controlling DCs activation and function, which is critical for prevention of autoimmunity.

5-Hydroxymethylfurfural Enhances the Antiviral Immune Response in Macrophages through the Modulation of RIG-I-Mediated Interferon Production and the JAK/STAT Signaling Pathway.

5-Hydroxymethylfurfural (5-HMF) exists in a wide range of sugar-rich foods and traditional Chinese medicines. The role of 5-HMF in antiviral innate immunity and its mechanism have not been reported previously. In this study, we reveal for the first time that 5-HMF upregulates the production of retinoic acid-inducible gene I (RIG-I)-mediated type I interferon (IFN) as a response to viral infection. IFN-ß and IFN-stimulated chemokine gene expressions induced by the vesicular stomatitis virus (VSV) are upregulated in RAW264.7 cells and primary peritoneal macrophages after treatment with 5-HMF, a natural product that appears to inhibit the efficiency of viral replication. Meanwhile, 5-HMF-pretreated mice show enhanced innate antiviral immunity, increased serum levels of IFN-ß, and reduced morbidity and viral loads upon infection with VSV. Thus, 5-HMF can be seen to have a positive effect on enhancing type I IFN production. Mechanistically, 5-HMF upregulates the expression of RIG-I in macrophages, resulting in an acceleration of the RIG-I signaling pathway activation. Additionally, STAT1 and STAT2 phosphorylations, along with the expression of IFN-stimulated chemokine genes induced by IFN-α/ß, were also enhanced in macrophages cotreated with 5-HMF. In summary, these findings indicate that 5-HMF not only can induce type I IFN production but also can enhance IFN-JAK/STAT signaling, leading to a novel immunomodulatory mechanism against viral infection. In conclusion, our study reveals a previously unrecognized effect of 5-HMF in the antiviral innate immune response and suggests new potential of utilizing 5-HMF for controlling viral infection.

Long Noncoding RNA XIST Contributes to Cervical Cancer Development Through Targeting miR-889-3p/SIX1 Axis.

Background: Cervical cancer (CC) is one of the most common cancers among women in the world. Long noncoding RNAs and microRNAs were identified as important regulators in many physiological processes. The objective of this study was to illuminate the mechanism of X-inactive-specific transcript (XIST)/miR-889-3p/Sine oculis homeobox 1 (SIX1) axis in CC. Methods: The expression levels of XIST, miR-889-3p, and SIX1 were detected by quantitative real-time polymerase chain reaction. Cell proliferation was assessed by cell counting Kit 8 assay. Cell migration and invasion were evaluated by transwell assay. Cell apoptosis was detected by flow cytometry assay. Murine model was established using transfected Me180 cell. The interaction among XIST, miR-889-3p, and SIX1 was tested by dual-luciferase reporter and RNA immunoprecipitation assays. Protein level of SIX1 was measured by Western blot. Results: XIST was highly expressed in CC tissues and cells. Silenced XIST inhibited proliferation, migration, and invasion and induced apoptosis. Moreover, XIST silencing blocked tumor growth in vivo. XIST directly bound to miR-889-3p, and XIST promoted proliferation, migration, and invasion and hindered apoptosis by suppressing miR-889-3p expression. MiR-889-3p targeted SIX1 and negatively regulated SIX1 expression. Furthermore, miR-889-3p had a low expression and SIX1 had a high expression in CC tissues and cells. XIST knockdown reduced SIX1 level by targeting miR-889-3p. In addition, miR-889-3p inhibition abolished the effects of SIX silencing on proliferation, migration, invasion, and apoptosis. Conclusion: XIST knockdown restrained cell proliferation, migration, and invasion and promoted apoptosis by regulating miR-889-3p/SIX1 axis.