sEH promotes macrophage phagocytosis and lung clearance of Streptococcus pneumoniae

Lactobacillus acidophilus protects against Corynebacterium pseudotuberculosis infection by regulating the autophagy of macrophages and maintaining gut microbiota homeostasis in C57BL/6 mice

Corynebacterium pseudotuberculosis (C. p), a facultative intracellular bacterium, is an important zoonotic pathogen that causes abscesses and pyogenic granulomas. The relationship between gut microbiota and host health or diseases has received increasing attention. However, the role of gut microbiota in the process of C. p infection is still unclear. In this study, we established a C. p infection model in C57BL/6 mice and examined the impact of preemptive oral administration Lactobacillus acidophilus (L. acidophilus) on infection. Our findings revealed that C. p infection led to pronounced pathological alterations in the liver and kidneys, characterized by abscess formation, intense inflammatory responses, and bacterial overload. Remarkably, these deleterious effects were greatly relieved by oral administration of L. acidophilus before infection with C. p. Additionally, we further found that during C. p infection, peritoneal macrophages (PMs) of mice orally administered with L. acidophilus accumulated more rapidly at sites of infection. Furthermore, our results showed that PMs from mice with oral L. acidophilus administration showed a stronger C. p clearance effect, and this was mediated by high expression of LC3-II protein. Meanwhile, oral administration of L. acidophilus protected the gut microbiota disorder in C57BL/6 mice caused by C. p infection. In summary, our study demonstrates that oral administration of L. acidophilus confers effective protection against C. p infection in C57BL/6 mice by modulating macrophage autophagy, thereby augmenting bacterial clearance and preserving gut microbiota and function stability. These findings position L. acidophilus as a viable probiotic candidate for the clinical prevention of C. p infection.

IMPORTANCE

Corynebacterium pseudotuberculosis (C. p) is known to induce a range of chronic diseases in both animals and humans. Currently, clinical treatment for C. p infection mainly relies on antibiotic therapy or surgical intervention. However, excessive use of antibiotics may increase the risk of drug-resistant strains, and the effectiveness of treatment remains unsatisfactory. Furthermore, surgical procedures do not completely eradicate pathogens and can easily cause environmental pollution. Probiotic interventions are receiving increasing attention for improving the body's immune system and maintaining health. In this study, we established a C. p infection model in C57BL/6 mice to explore the impact of Lactobacillus acidophilus during C. p infection. Our results showed that L. acidophilus effectively protected against C. p infection by regulating the autophagy of macrophages and maintaining intestinal microbiota homeostasis. This study may provide a new strategy for the prevention of C. p infection.

Production and Release of Proinflammatory Mediators by the Cockroach Allergen Bla g 1 via a Shared Membrane-Destabilization Mechanism

The cockroach allergen Bla g 1 encloses an exceptionally large hydrophobic cavity, which allows it to bind and deliver unsaturated fatty acid ligands. Bla g 1-mediated delivery of naturally occurring (nMix) ligands has been shown to destabilize lipid membranes, contributing to its digestive/antiviral functions within the source organism. However, the consequences of this activity on Bla g 1 allergenicity following human exposure remain unknown. In this work, we show that Bla g 1-mediated membrane disruption can induce a proinflammatory immune response in mammalian cells via two complementary pathways. At high concentrations, the cytotoxic activity of Bla g 1 induces the release of proinflammatory cytosolic contents including damage-associated molecular patterns (DAMPs) such as heat-shock Protein-70 (HSP70) and the cytokine interleukin-1 (IL-1β). Sublytic concentrations of Bla g 1 enhanced the ability of phospholipase A2 (PLA2) to extract and hydrolyze phospholipid substrates from cellular membranes, stimulating the production of free polyunsaturated fatty acids (PUFAs) and various downstream inflammatory lipid mediators. Both of these effects are dependent on the presence of Bla g 1's natural fatty-acid (nMix) ligands with CC50 values corresponding to the concentrations required for membrane destabilization reported in previous studies. Taken together, these results suggest that mechanisms through which Bla g 1-mediated lipid delivery and membrane destabilization could directly contribute to cockroach allergic sensitization.

Identification and functional analysis of perforin 1 from largemouth bass (Micropterus salmoides)

In this study, we present the first cloning and identification of perforin (MsPRF1) in largemouth bass (Micropterus salmoides). The full-length cDNA of MsPRF1 spans 1572 base pairs, encoding a 58.88 kDa protein consisting of 523 amino acids. Notably, the protein contains MACPF and C2 structural domains. To evaluate the expression levels of MsPRF1 in various healthy largemouth bass tissues, real-time quantitative PCR was employed, revealing the highest expression in the liver and gut. After the largemouth bass were infected by Nocardia seriolae, the mRNA levels of MsPRF1 generally increased within 48 h. Remarkably, the recombinant protein MsPRF1 exhibits inhibitory effects against both Gram-negative and Gram-positive bacteria. Additionally, the largemouth bass showed a higher survival rate in the N. seriolae challenge following the intraperitoneal injection of rMsPRF1, with observed reductions in the tissue bacterial loads. Moreover, rMsPRF1 demonstrated a significant impact on the phagocytic and bactericidal activities of largemouth bass MO/MΦ cells, concurrently upregulating the expression of pro-inflammatory factors. These results demonstrate that MsPRF1 has a potential role in the immune response of largemouth bass against N. seriolae infection.

Effects of sEH inhibition on the eicosanoid and cytokine storms in SARS-CoV-2-infected mice

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection involves an initial viral infection phase followed by a host-response phase that includes an eicosanoid and cytokine storm, lung inflammation and respiratory failure. While vaccination and early anti-viral therapies are effective in preventing or limiting the pathogenic host response, this latter phase is poorly understood with no highly effective treatment options. Inhibitors of soluble epoxide hydrolase (sEH) increase levels of anti-inflammatory molecules called epoxyeicosatrienoic acids (EETs). This study aimed to investigate the impact of sEH inhibition on the host response to SARS-CoV-2 infection in a mouse model with human angiotensin-converting enzyme 2 (ACE2) expression. Mice were infected with SARS-CoV-2 and treated with either vehicle or the sEH inhibitor 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU). At day 5 post-infection, SARS-CoV-2 induced weight loss, clinical signs, a cytokine storm, an eicosanoid storm, and severe lung inflammation with ~50% mortality on days 6-8 post-infection. SARS-CoV-2 infection induced lung expression of phospholipase A2 (PLA2), cyclooxygenase (COX) and lipoxygenase (LOX) pathway genes, while suppressing expression of most cytochrome P450 genes. Treatment with the sEH inhibitor TPPU delayed weight loss but did not alter clinical signs, lung cytokine expression or overall survival of infected mice. Interestingly, TPPU treatment significantly reversed the eicosanoid storm and attenuated viral-induced elevation of 39 fatty acids and oxylipins from COX, LOX and P450 pathways, which suggests the effects at the level of PLA2 activation. The suppression of the eicosanoid storm by TPPU without corresponding changes in lung cytokines, lung inflammation or mortality reveals a surprising dissociation between systemic oxylipin and cytokine signaling pathways during SARS-CoV-2 infection and suggests that the cytokine storm is primarily responsible for morbidity and mortality in this animal model.

Overexpression of soluble epoxide hydrolase reduces post-ischemic recovery of cardiac contractile function

Cytochromes P450 can metabolize endogenous fatty acids, such as arachidonic acid, to bioactive lipids such as epoxyeicosatrienoic acids (EETs) that have beneficial effects. EETs protect hearts against ischemic damage, heart failure or fibrosis; however, their effects are limited by hydrolysis to less active dihydroxy oxylipins by soluble epoxide hydrolase (sEH), encoded by the epoxide hydrolase 2 gene (EPHX2, EC 3.3.2.10). Pharmacological inhibition or genetic disruption of sEH/EPHX2 have been widely studied for their impact on cardiovascular diseases. Less well studied is the role of increased EPHX2 expression, which occurs in a substantial human population that carries the EPHX2 K55R polymorphism or after induction by inflammatory stimuli. Herein, we developed a mouse model with cardiomyocyte-selective expression of human EPHX2 (Myh6-EPHX2) that has significantly increased total EPHX2 expression and activity. Myh6-EPHX2 hearts exhibit strong, cardiomyocyte-selective expression of EPHX2. EPHX2 mRNA, protein, and epoxide hydrolysis measurements suggest that Myh6-EPHX2 hearts have 12-fold increase in epoxide hydrolase activity relative to wild type (WT) hearts. This increased activity significantly decreased epoxide:diol ratios in vivo. Isolated, perfused Myh6-EPHX2 hearts were not significantly different from WT hearts in basal parameters of cardiac function; however, compared to WT hearts, Myh6-EPHX2 hearts demonstrated reduced recovery of heart contractile function after ischemia and reperfusion (I/R). This impaired recovery after I/R correlated with reduced activation of PI3K/AKT and GSK3β signaling pathways in Myh6-EPHX2 hearts compared to WT hearts. In summary, the Myh6-EPHX2 mouse line represents a novel model of cardiomyocyte-selective overexpression of EPHX2 that has detrimental effects on cardiac function.

Thymopentin plays a key role in restoring the function of macrophages to alleviate the sepsis process

Immune dysfunction is one of the leading causes of death of sepsis. How to regulate host immune functions to improve prognoses of septic patients has always been a clinical focus. Here we elaborate on the efficacy and potential mechanism of a classical drug, thymopentin (TP5). TP5 could decrease peritoneal bacterial load, and reduce inflammatory cytokine levels both in the peritoneal lavage fluid (PLF) and serum, alleviate pathological injuries in tissue and organ, coaxed by cecal ligation and perforation (CLP) in mice, ultimately improve the prognosis of septic mice. Regarding the mechanism, using RNA-seq and flow cytometry, we found that TP5 induced peptidoglycan recognition protein 1 (PGLYRP1) expression, increased phagocytosis and restored TNF-α expression of small peritoneal macrophage (SPM) in the septic mice. This may be increased SPM's ability to clear peritoneal bacteria, thereby attenuates the inflammatory response both in the peritoneal cavity and the serum. It was shown that TP5 plays a key role in restoring the function of peritoneal macrophages to alleviate the sepsis process. We reckon that this is closely relevant to SPM phagocytosis, which might involve increased PGLYRP1 expression and restored TNF-α secretion.

Anti-inflammatory of disenecionyl cis-khellactone in LPS-stimulated RAW264.7 cells and the its inhibitory activity on soluble epoxide hydrolase

The objective of the present study was to investigate anti-inflammatory effects of disenecionyl cis-khellactone (DK) isolated from Peucedanum japonicum Thunberg, a traditional edible plant, in RAW264.7 cells stimulated with lipopolysaccharide (LPS). Anti-inflammatory effects of DK were analyzed using various techniques, including NO assay, Western blot analysis, enzyme-linked immunosorbent assay (ELISA), real-time PCR, and immunofluorescence staining. It was revealed that DK reduced the production of pro-inflammatory cytokines including Monocyte chemoattractant protein-1 (MCP-1), Tumor necrosis factor-α (TNF-α), Interleukin 1β (IL-1β), and Interleukin 6 (IL-6) in RAW264.7 cells stimulated with LPS. It was revealed that DK effectively downregulated expression levels of iNOS and COX-2 due to inhibition of NF-κB activation and suppressing the phosphorylation of p38 and jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) phosphorylation. Also, soluble epoxide hydrolase activity and expression were decreased by the proinflammatory inhibitor, DK. Finally, findings of this study suggest that DK isolated from P. japonicum might have potential as a therapeutic candidate for inflammatory diseases.

Genetic deletion or pharmacological inhibition of soluble epoxide hydrolase attenuated particulate matter 2.5 exposure mediated lung injury

Air pollution represented by particulate matter 2.5 (PM2.5) is closely related to diseases of the respiratory system. Although the understanding of its mechanism is limited, pulmonary inflammation is closely correlated with PM2.5-mediated lung injury. Soluble epoxide hydrolase (sEH) and epoxy fatty acids play a vital role in the inflammation. Herein, we attempted to use the metabolomics of oxidized lipids for analyzing the relationship of oxylipins with lung injury in a PM2.5-mediated mouse model, and found that the cytochrome P450 oxidases/sEH mediated metabolic pathway was involved in lung injury. Furthermore, the sEH overexpression was revealed in lung injury mice. Interestingly, sEH genetic deletion or the selective sEH inhibitor TPPU increased levels of epoxyeicosatrienoic acids (EETs) in lung injury mice, and inactivated pulmonary macrophages based on the MAPK/NF-κB pathway, resulting in protection against PM2.5-mediated lung injury. Additionally, a natural sEH inhibitor luteolin from Inula japonica displayed a pulmonary protective effect towards lung injury mediated by PM2.5 as well. Our results are consistent with the sEH message and protein being both a marker and mechanism for PM2.5-induced inflammation, which suggest its potential as a pharmaceutical target for treating diseases of the respiratory system.

Soluble epoxide hydrolase deficiency promotes liver regeneration and ameliorates liver injury in mice by regulating angiocrine factors and angiogenesis

BACKGROUND

Soluble epoxide hydrolase (sEH) is a key enzyme for the hydrolysis of epoxyeicosatrienoic acids (EETs) and has been implicated in the pathogenesis of hepatic inflammation, fibrosis, cancer, and nonalcoholic fatty liver disease. However, the role of sEH in liver regeneration and injury remains unclear.

METHODS

This study used sEH-deficient (sEH^-/-) mice and wild-type (WT) mice. Hepatocyte proliferation was assessed by immunohistochemical (IHC) staining for Ki67. Liver injury was evaluated by histological staining with hematoxylin and eosin (H&E), Masson's trichrome, and Sirius red, as well as IHC staining for α-SMA. Hepatic macrophage infiltration and angiogenesis were reflected by IHC staining for CD68 and CD31. Liver angiocrine levels were detected by ELISA. The mRNA levels of angiocrine or cell cycle-related genes were measured by quantitative real-time RT-PCR (qPCR). The protein levels of cell proliferation-related protein and phosphorylated signal transducer and activator of transcription 3 (STAT3) were detected by western blotting.

RESULTS

sEH mRNA and protein levels were significantly upregulated in mice after 2/3 partial hepatectomy (PHx). Compared with WT mice, sEH^-/- mice exhibited a higher liver/body weight ratio and more Ki67-positive cells on days 2 and 3 after PHx. The accelerated liver regeneration in sEH^-/- mice was attributed to angiogenesis and endothelial-derived angiocrine (HGF) production. Subsequently, hepatic protein expression of cyclinD1 (CYCD1) and the downstream direct targets of the STAT3 pathway, such as c-fos, c-jun, and c-myc, were also suppressed post-PHx in sEH^-/- compared to WT mice. Furthermore, sEH deficiency attenuated CCl₄-induced acute liver injury and reduced fibrosis in both CCl₄ and bile duct ligation (BDL)-induced liver fibrosis rodent models. Compared with WT mice, sEH^-/- mice had slightly decreased hepatic macrophage infiltration and angiogenesis. Meanwhile, sEH^-/- BDL mice had more Ki67-positive cells in the liver than WT BDL mice.

CONCLUSIONS

sEH deficiency alters the angiocrine profile of liver endothelial to accelerate hepatocyte proliferation and liver regeneration, and blunts acute liver injury and fibrosis by inhibiting inflammation and angiogenesis. sEH inhibition is a promising target for liver diseases to improve liver regeneration and damage.

A novel molecular signature for predicting prognosis and immunotherapy response in osteosarcoma based on tumor-infiltrating cell marker genes

Background

Tumor infiltrating lymphocytes (TILs), the main component in the tumor microenvironment, play a critical role in the antitumor immune response. Few studies have developed a prognostic model based on TILs in osteosarcoma.

Methods

ScRNA-seq data was obtained from our previous research and bulk RNA transcriptome data was from TARGET database. WGCNA was used to obtain the immune-related gene modules. Subsequently, we applied LASSO regression analysis and SVM algorithm to construct a prognostic model based on TILs marker genes. What’s more, the prognostic model was verified by external datasets and experiment in vitro.

Results

Eleven cell clusters and 2044 TILs marker genes were identified. WGCNA results showed that 545 TILs marker genes were the most strongly related with immune. Subsequently, a risk model including 5 genes was developed. We found that the survival rate was higher in the low-risk group and the risk model could be used as an independent prognostic factor. Meanwhile, high-risk patients had a lower abundance of immune cell infiltration and many immune checkpoint genes were highly expressed in the low-risk group. The prognostic model was also demonstrated to be a good predictive capacity in external datasets. The result of RT-qPCR indicated that these 5 genes have differential expression which accorded with the predicting outcomes.

Conclusions

This study developed a new molecular signature based on TILs marker genes, which is very effective in predicting OS prognosis and immunotherapy response.

The mechanism of Renshen-Fuzi herb pair for treating heart failure-Integrating a cardiovascular pharmacological assessment with serum metabolomics

Background: Renshen-Fuzi herb pair (RS-FZ) is often used in the clinical treatment of heart failure (HF) and has a remarkable therapeutic effect. However, the mechanism of RS-FZ for treating HF remains unclear. In our study, we explored the mechanism of RS-FZ for treating HF. Methods: Evaluation of RS-FZ efficacy by cardiovascular pharmacology. Moreover, Global metabolomics profiling of the serum was detected by UPLC-QTOF/MS. Multivariate statistics analyzed the specific serum metabolites and corresponding metabolic pathways. Combining serum metabolomics with network pharmacology, animal experiments screened and validated the critical targets of RS-FZ intervention in HF. Results: RS-FZ significantly ameliorated myocardial fibrosis, enhanced cardiac function, and reduced the serum HF marker (brain natriuretic peptide) level in rats with HF. Through topological analysis of the "Metabolite-Target-Component" interaction network, we found that 79 compounds of RS-FZ directly regulated the downstream specific serum metabolites by acting on four critical target proteins (CYP2D6, EPHX2, MAOB, and ENPP2). The immunohistochemistry results showed that RS-FZ observably improved the expression of CYP2D6 and ENPP2 proteins while decreasing the expression of EPHX2 and MAOB proteins dramatically. Conclusion: The integrated cardiovascular pharmacological assessment with serum metabolomics revealed that RS-FZ plays a crucial role in the treatment of HF by intervening in CYP2D6, EPHX2, MAOB, and ENPP2 target proteins. It provides a theoretical basis for RS-FZ for treating HF.

Inflammation and oxidative stress as mediators of the impacts of environmental exposures on human pregnancy: Evidence from oxylipins

Inflammation and oxidative stress play major roles in healthy and pathological pregnancy. Environmental exposure to chemical pollutants may adversely affect maternal and fetal health in pregnancy by dysregulating these critical underlying processes of inflammation and oxidative stress. Oxylipins are bioactive lipids that play a major role in regulating inflammation and increasing lines of evidence point towards an importance in pregnancy. The biosynthetic production of oxylipins requires oxygenation of polyunsaturated fatty acids, which can occur through several well-characterized enzymatic and nonenzymatic pathways. This review describes the state of the science of epidemiologic evidence on oxylipin production in pregnancy and its association with 1) key pregnancy outcomes and 2) environmental exposures. We searched PubMed for studies of pregnancy that measured one or more oxylipin analytes during pregnancy or delivery. We evaluated oxylipin associations with three categories of adverse pregnancy outcomes, including preeclampsia, preterm birth, and fetal growth restriction, along with several categories of environmental pollutants. The majority of studies evaluated one to two oxylipins, most of which focused on oxylipins produced from nonenzymatic processes of oxidative stress. However, an increasing number of recent studies have leveraged technological advancements to profile a large number of oxylipins produced from distinct biosynthetic pathways. Although the literature indicated robust evidence that oxylipins produced via nonenzymatic pathways are associated with pregnancy outcomes and environmental exposures, evidence for enzymatically produced oxylipins showed that associations may differ between biosynthetic pathways. Along with summarizing this evidence, we review promising therapeutic options to regulate oxylipin production and provide a set of recommendations for future epidemiologic studies in these research areas. Further evidence is needed to improve our understanding of how oxylipins may act as key biological mediators for the adverse effects of environmental pollutants on pregnancy outcomes.

CYP450 Epoxygenase Metabolites, Epoxyeicosatrienoic Acids, as Novel Anti-Inflammatory Mediators

Inflammation plays a crucial role in the initiation and development of a wide range of systemic illnesses. Epoxyeicosatrienoic acids (EETs) are derived from arachidonic acid (AA) metabolized by CYP450 epoxygenase (CYP450) and are subsequently hydrolyzed by soluble epoxide hydrolase (sEH) to dihydroxyeicosatrienoic acids (DHETs), which are merely biologically active. EETs possess a wide range of established protective effects on many systems of which anti-inflammatory actions have gained great interest. EETs attenuate vascular inflammation and remodeling by inhibiting activation of endothelial cells and reducing cross-talk between inflammatory cells and blood vessels. EETs also process direct and indirect anti-inflammatory properties in the myocardium and therefore alleviate inflammatory cardiomyopathy and cardiac remodeling. Moreover, emerging studies show the substantial roles of EETs in relieving inflammation under other pathophysiological environments, such as diabetes, sepsis, lung injuries, neurodegenerative disease, hepatic diseases, kidney injury, and arthritis. Furthermore, pharmacological manipulations of the AA-CYP450-EETs-sEH pathway have demonstrated a contribution to the alleviation of numerous inflammatory diseases, which highlight a therapeutic potential of drugs targeting this pathway. This review summarizes the progress of AA-CYP450-EETs-sEH pathway in regulation of inflammation under different pathological conditions and discusses the existing challenges and future direction of this research field.

miR-223-3p contributes to suppressing NLRP3 inflammasome activation in Streptococcus equi ssp. zooepidemicus infection

Streptococcus equi subsp. zooepidemicus (SEZ) is an essential pathogen in a range of species, causing a worldwide variety of diseases, such as meningitis, endocarditis, and septicaemia. Studies have shown that microRNAs (miRNAs), which regulate target genes at the post-transcriptional level, play an important regulatory role in the organism. In this study, the infection of J774A.1 murine macrophages with SEZ up-regulated NLRP3 inflammasome and downstream pathways accompanied by miR-223-3p down-regulation. Through computational prediction and experimental confirmation, we have shown that miR-223-3p directly targets the NLRP3 mRNA. Consequently, overexpression of miR-223-3p suppressed NLRP3 inflammasome activation and downstream pathways in response to SEZ infection. The miR-223-3p inhibitor exhibited the opposite effect, causing hyperactivation of NLRP3 inflammation activation and downstream pathways. Additionally, we further demonstrated that miRNA-223-3p inhibited the secretion of IL-1β and IL-18 by regulating the NLRP3/caspase-1 pathway. Furthermore, intravenous administration of miR-223-3p significantly decreased inflammation in mice in response to SEZ. In conclusion, our results demonstrated that miR-223-3p contributes to suppressing the NLRP3 inflammasome activation in SEZ infection, contributing novel evidence to identify a therapeutic target for treating SEZ.