Associations between estradiol and hyperuricemia and the mediating effects of TC, TG, and TyG: NHANES 2013-2016.

Objectives: To explore the relationship between estradiol (E2) and the incidence of hyperuricemia (HUA) in adult women and to explore whether glucolipid metabolism disorders play a mediating role in mediating this relationship. Methods: A total of 2,941 participants aged 20-65 years were included in the National Health and Nutrition Examination Survey (NHANES) 2013-2016. Multivariate logistic regression analysis was performed to evaluate the correlations of E2 with HUA. Multivariate linear regression analysis was performed to evaluate the associations between E2 and triglyceride (TG), total cholesterol (TC), and the triglyceride-glucose index (TyG). The restricted cubic spline (RCS) model was used to further explore the association between E2 and HUA and between TG, TC, and TyG and HUA. Mediation analyses were performed to examine whether TC, TG, and TyG mediated the relationship between E2 and HUA. Results: After adjusting for covariates, logistic regression revealed that ln(E2) was significantly associated with HUA in the female subgroup (p = 0.035) and that the incidence of HUA tended to increase with decreasing ln(E2) (p for trend = 0.026). Linear regression showed that E2 was significantly associated with TC (p = 0.032), TG (p = 0.019), and TyG (p = 0.048). The RCS model showed that ln(E2) was linearly correlated with the incidence of HUA (p-overall = 0.0106, p-non-linear = 0.3030). TC and TyG were linearly correlated with HUA (TC: p-overall = 0.0039, p-non-linear = 0.4774; TyG: p-overall = 0.0082, p-non-linear = 0.0663), whereas TG was non-linearly correlated with HUA. Mediation analyses revealed that TC, TG, and TyG significantly mediated the relationship between ln(E2) and HUA (TC, indirect effect: -0.00148, 7.5%, p = 0.008; TG, indirect effect: -0.00062, 3.1%, p = 0.004; TyG, indirect effect: -0.00113, 5.6%, p = 0.016). Conclusion: In conclusion, this study demonstrated that compared with women aged 20-45 years, women aged 45-55 years and 55-65 years had lower E2 levels and a greater incidence of HUA. E2 levels and the incidence of HUA were negatively associated in female individuals but not in male individuals. In addition, TC, TG, and TyG, which are markers of glucolipid metabolism, played a mediating role in the association between E2 and HUA.

PD-1/PD-L1 Provides Protective Role in Hypoxia-Induced Pulmonary Vascular Remodeling.

BACKGROUND: Hypoxia-induced pulmonary hypertension (HPH) is a T helper 17 cell response-driven disease, and PD-1 (programmed cell death 1)/PD-L1 (programmed cell death-ligand 1) inhibitor-associated pulmonary hypertension has been reported recently. This study is designed to explore whether the PD-1/PD-L1 pathway participates in HPH via regulating endothelial dysfunction and T helper 17 cell response. METHODS: Lung tissue samples were obtained from eligible patients. Western blotting, immunohistochemistry, and immunofluorescence techniques were used to assess protein expression, while immunoprecipitation was utilized to detect ubiquitination. HPH models were established in C57BL/6 WT (wild-type) and PD-1-/- mice, followed by treatment with PD-L1 recombinant protein. Adeno-associated virus vector delivery was used to upregulate PD-L1 in the endothelial cells. Endothelial cell function was assessed through assays for cell angiogenesis and adhesion. RESULTS: Expression of the PD-1/PD-L1 pathway was downregulated in patients with HPH and mouse models, with a notable decrease in PD-L1 expression in endothelial cells compared with the normoxia group. In comparison to WT mice, PD-1-/- mice exhibited a more severe HPH phenotype following exposure to hypoxia, However, administration of PD-L1 recombinant protein and overexpression of PD-L1 in lung endothelial cells mitigated HPH. In vitro, blockade of PD-L1 with a neutralizing antibody promoted endothelial cell angiogenesis, adhesion, and pyroptosis. Mechanistically, hypoxia downregulated PD-L1 protein expression through ubiquitination. Additionally, both in vivo and in vitro, PD-L1 inhibited T helper 17 cell response through the PI3K (phosphoinositide 3-kinase)/AKT (protein kinase B)/mTOR (mammalian target of rapamycin) pathway in HPH. CONCLUSIONS: PD-1/PD-L1 plays a role in ameliorating HPH development by inhibiting T helper 17 cell response through the PI3K/AKT/mTOR pathway and improving endothelial dysfunction, suggesting a novel therapeutic indication for PD-1/PD-L1-based immunomodulatory therapies in the treatment of HPH.

Trichinella spiralis Paramyosin Alleviates Collagen-Induced Arthritis in Mice by Modulating CD4+ T Cell Differentiation.

Rheumatoid arthritis (RA) is an autoimmune disease that significantly impacts quality of life by disrupting CD4+ T cell immune homeostasis. The identification of a low-side-effect drug for RA treatment is urgently needed. Our previous study suggests that Trichinella spiralis paramyosin (Ts-Pmy) has immunomodulatory effects, but its potential effect on CD4+ T cell response in RA remains unclear. In this study, we used a murine model to investigate the role of rTs-Pmy in regulating CD4+ T cell differentiation in collagen-induced arthritis (CIA). Additionally, we assessed the impact of rTs-Pmy on CD4+ T cell differentiation towards the Th1 and Th17 phenotypes, which are associated with inflammatory responses in arthritis, using in vitro assays. The results demonstrated that rTs-Pmy administration reduced arthritis severity by inhibiting Th1 and Th17 response while enhancing Treg response. Prophylactic administration of Ts-Pmy showed superior efficacy on CIA compared to therapeutic administration. Furthermore, in vitro assays demonstrated that rTs-Pmy could inhibit the differentiation of CD4+ T cells into Th1 and Th17 while inducing the production of Tregs, suggesting a potential mechanism underlying its therapeutic effects. This study suggests that Ts-Pmy may ameliorate CIA by restoring the immune balance of CD4+ T cells and provides new insights into the mechanism through which helminth-derived proteins exert their effects on autoimmune diseases.

Crystal structure of Trichinella spiralis calreticulin and the structural basis of its complement evasion mechanism involving C1q.

Helminths produce calreticulin (CRT) to immunomodulate the host immune system as a survival strategy. However, the structure of helminth-derived CRT and the structural basis of the immune evasion process remains unclarified. Previous study found that the tissue-dwelling helminth Trichinella spiralis produces calreticulin (TsCRT), which binds C1q to inhibit activation of the complement classical pathway. Here, we used x-ray crystallography to resolve the structure of truncated TsCRT (TsCRTΔ), the first structure of helminth-derived CRT. TsCRTΔ was observed to share the same binding region on C1q with IgG based on the structure and molecular docking, which explains the inhibitory effect of TsCRT on C1q-IgG-initiated classical complement activation. Based on the key residues in TsCRTΔ involved in the binding activity to C1q, a 24 amino acid peptide called PTsCRT was constructed that displayed strong C1q-binding activity and inhibited C1q-IgG-initiated classical complement activation. This study is the first to elucidate the structural basis of the role of TsCRT in immune evasion, providing an approach to develop helminth-derived bifunctional peptides as vaccine target to prevent parasite infections or as a therapeutic agent to treat complement-related autoimmune diseases.

Role of Zhiqiao Chuanlian decoction in the treatment of food accumulation fever: Network pharmacology and animal experiments.

Objective: Food accumulation fever (FAF), a common clinical disease in children, is generally induced by the excessive intake of high-calorie or high-fat foods. Zhiqiao Chuanlian decoction (ZQCLD) is a classical traditional Chinese medicine (TCM) that may have therapeutic effects on FAF. Methods: Network pharmacological analyses of ZQCLD and FAF were conducted. Animal experiments lasted for 14 days. Rats in the model, positive control, and low-, medium-, and high-dose groups were fed a high-calorie diet. On days 11-14, the positive group was given a domperidone solution. The low-, medium-, and high-dose groups were administered different concentrations of ZQCLD. The body temperature, gastric emptying rate, and intestinal propulsion rate were measured. Relevant indicators were determined by ELISA. Results: The main target proteins included IL-1ß, C-C motif chemokine 2 (CCL2), prostaglandin G/H synthase 2 (PTGS2), transcription factor AP-1 (JUN), haem oxygenase 1 (HMOX1), interferon-gamma (IFN-γ), peroxisome proliferator-activated receptor-gamma (PPAR-γ), and inducible nitric oxide synthase (NOS2/iNOS). Compared with those in the control group, body weight, gastric emptying rate, intestinal propulsion rate, and neuronal nitric oxide synthase (NOS1/nNOS) levels were significantly lower in the model group, whereas body temperature and endotoxin, interleukin-1ß (IL-1ß), PGE2, and iNOS levels were increased. In each treatment group, body temperature and PGE2 levels returned to normal levels. Compared with those in the model group, the gastric emptying rates in the positive group and the low- and medium-dose groups increased; the intestinal propulsion rates were higher in the medium- and high-dose groups, whereas the endotoxin and IL-1ß levels were lower; and the nNOS level was higher in the high-dose group, whereas the iNOS level was lower. Conclusions: ZQCLD may treat FAF by regulating jejunal IL-1ß and nNOS, serum endotoxin, and hypothalamic PGE2 and iNOS levels.

Levels and trends of maternal death in Baoan district, Shenzhen, China, 1999-2022.

Background: China had achieved impressive success in improving maternal health, while the progress of reducing maternal mortality ratio (MMR) varied across regions. Some studies had reported maternal mortality from national or provincial perspective, but researches of the MMR on long-term period at the city or county level rare been reported. Shenzhen has experienced significant socioeconomic and health changes, reflecting the typical development of China's coastal city. This study mainly introduced the levels and trends of maternal death in Baoan district, Shenzhen from 1999 to 2022. Methods: Maternal mortality data were extracted from registration forms and the Shenzhen Maternal and Child Health Management System. Linear-by-Linear Association tests were used to evaluate the trends of MMR among different groups. The study periods were divided into three stages by 8-year interval and χ2 test or Fisher's test was used to test the difference in maternal deaths of different periods. Results: During 1999-2022, a total of 137 maternal deaths occurred in Baoan, the overall MMR was 15.91 per 100,000 live births, declined by 89.31% with an annualized rate of 9.26%. The MMR declined by 68.15% in migrant population, with an annualized rate of 5.07%, faster than that in permanent population (48.73%, 2.86%). The MMR due to direct and indirect obstetric causes shown a downward trend (P<0.001) and the gap between them narrowed to 14.29% during 2015-2022. The major causes of maternal deaths were obstetric hemorrhage (4.41 per 100,000 live births), amniotic fluid embolism (3.37 per 100,000 live births), medical complications (2.44 per 100,000 live births) and pregnancy-induced hypertension (1.97 per 100,000 live births), the MMR due to the above causes all shown decreasing trends (P < 0.01), pregnancy-induced hypertension became the leading cause of deaths during 2015-2022. The constituent ratio of maternal deaths with advanced age significantly increased by 57.78% in 2015-2022 compared with in 1999-2006. Conclusions: Baoan district had made encouraging progress in improving maternal survival, especially in migrant population. To further reduce the MMR, strengthening professional training to improve the capacity of obstetricians and physicians, increasing the awareness and ability of self-help health care among elderly pregnant women were in urgent need.

Bone erosion in inflammatory arthritis is attenuated by Trichinella spiralis through inhibiting M1 monocyte/macrophage polarization.

Helminths and helminth-derived products hold promise for treating joint bone erosion in rheumatoid arthritis (RA). However, the mechanisms of helminths ameliorating the osteoclastic bone destruction are incompletely understood. Here, we report that Trichinella spiralis infection or treatment with the excreted/secreted products of T. spiralis muscle larvae (MES) attenuated bone erosion and osteoclastogenesis in mice with collage-induced arthritis (CIA) through inhibiting M1 monocyte/macrophage polarization and the production of M1-related proinflammatory cytokines. In vitro, MES inhibited LPS-induced M1 macrophage activation while promoting IL-4-induced M2 macrophage polarization. Same effects of MES were also observed in monocytes derived from RA patients, wherein MES treatment suppressed LPS-induced M1 cytokine production. Moreover, MES treatment attenuated LPS and RANKL co-stimulated osteoclast differentiation from the RAW264.7 macrophages through inhibiting activation of the NF-κB rather than MAPK pathway. This study provides insight into the M1 subset as a potential target for helminths to alleviate osteoclastic bone destruction in RA.

Association between factors affecting language development and Chinese dyslexia among primary students / 中国学校卫生

Objective@#To explore the association between factors affecting language development and Chinese dyslexia, providing scientific evidence for prevention and intervention of dyslexia.@*Methods@#Twelve elementary schools were selected in Baoan, Shenzhen. The parents and head teachers of 12 868 children in grade 3-5 were surveyed by the Questionnaire for Children s Reading Ability, the Dyslexia Checklist for Chinese Children and the Pupil Rating Scale Revised Screening for Learning Disabilities.@*Results@#The prevalence rate of dyslexia was 2.71%, with 349 children suffering from dyslexia. Gender, parental education and occupations, family income, whether parents work away from home before their child was 3 years old, average time mother spends with her child daily and number of languages spoken in family had statistical significance on dyslexia(all P <0.05). After adjusting for parental education and occupations, and family income, the children who spent more than 1 hour with their mothers per day had a significantly reduced risk of dyslexia (1-2: OR =0.46; 3-4: OR =0.45; 5-6: OR =0.40; >7 h: OR =0.36, P <0.05); the children living in families where two languages were used for communication had a significantly reduced risk of dyslexia( OR=0.74, 95%CI=0.57-0.96, P =0.02). Children with a history of language development disorders had a significantly increased risk of dyslexia( OR=17.30, 95%CI=7.86-38.09, P <0.01).@*Conclusion@#Increase of time mother spend with their child daily and paying more attention to the children with a history of language development disorders can help to prevent the occurrence of dyslexia.

Excretory/Secretory Products From Trichinella spiralis Adult Worms Attenuated DSS-Induced Colitis in Mice by Driving PD-1-Mediated M2 Macrophage Polarization.

Helminth-modulated macrophages contribute to attenuating inflammation in inflammatory bowel diseases. The programmed death 1 (PD-1) plays an important role in macrophage polarization and is essential in the maintenance of immune system homeostasis. Here, we investigate the role of PD-1-mediated polarization of M2 macrophages and the protective effects of excretory/secretory products from Trichinella spiralis adult worms (AES) on DSS-induced colitis in mice. Colitis in mice was induced by oral administration of dextran sodium sulfate (DSS) daily. Mice with DSS-induced colitis were treated with T. spiralis AES intraperitoneally, and pathological manifestations were evaluated. Macrophages in mice were depleted with liposomal clodronate. Markers for M1-type (iNOS, TNF-α) and M2-type (CD206, Arg-1) macrophages were detected by qRT-PCR and flow cytometry. Macrophage expression of PD-1 was quantified by flow cytometry; RAW 264.7 cells and peritoneal macrophages were used for in vitro tests, and PD-1 gene knockout mice were used for in vivo investigation of the role of PD-1 in AES-induced M2 macrophage polarization. Macrophage depletion was found to reduce DSS-induced colitis in mice. Treatment with T. spiralis AES significantly increased macrophage expression of CD206 and Arg-1 and simultaneously attenuated colitis severity. We found T. spiralis AES to enhance M2 macrophage polarization; these findings were confirmed studying in vitro cultures of RAW264.7 cells and peritoneal macrophages from mice. Further experimentation revealed that AES upregulated PD-1 expression, primarily on M2 macrophages expressing CD206. The AES-induced M2 polarization was found to be decreased in PD-1 deficient macrophages, and the therapeutic effects of AES on colitis was reduced in PD-1 knockout mice. In conclusion, the protective effects of T. spiralis AES on DSS-induced colitis were found to associate with PD-1 upregulation and M2 macrophage polarization. Thus, PD-1-mediated M2 macrophage polarization is a key mechanism of helminth-induced modulation of the host immune system.

Therapeutic Efficacy of a Trichinella Spiralis Paramyosin-Derived Peptide Modified With a Membrane-Targeting Signal in Mice With Antigen-Induced Arthritis.

Helminth-derived molecules have the ability to modulate the host immune system. Our previous study identified a tetradecapeptide derived from Trichinella spiralis paramyosin (Ts-pmy) that could bind to human complement component C9 to inhibit its polymerization, making the peptide a candidate therapeutic agent for complement-related immune disorders. Here, the peptide underwent an N-terminal modification with a membrane-targeting signal (a unique myristoylated peptide) to improve its therapeutic efficacy. We found that the modified peptide had a binding affinity to human C9 that was similar to that of the original peptide, as confirmed by microscale thermophoresis assays. The binding of the modified peptide to human C9 resulted in the inhibition of C9-related complement activation, as reflected by the decreased Zn2+-induced C9 polymerization and the decreased C9-dependent lysis of rabbit erythrocytes. In addition, the original and modified peptides could both bind to recombinant mouse C9 and inhibit the C9-dependent lysis of rabbit erythrocytes in normal mouse serum (NMS), which meant that the peptides could cross the species barrier to inhibit complement activity in mice. Further in vitro and in vivo analyses confirmed that the peptide modification increased the retention time of the peptide. Furthermore, intraarticular injection of the modified peptide markedly ameliorated knee swelling and joint damage in mice with antigen-induced arthritis (AIA), as assessed histologically. These results suggested that the Ts-pmy-derived peptide modified with a membrane-targeting signal was a reasonable candidate therapeutic agent for membrane attack complex (MAC)-related diseases [such as rheumatoid arthritis (RA)] and the study presented a new modification method to improve the potential therapeutic effects of the peptide.

Dysmenorrhea increased the risk of postpartum depression in Chinese Han parturients.

Several studies have shown that dysmenorrhea increased the risk of depression. However, the association between dysmenorrhea and postpartum depression (PPD) is unclear. The purpose of this study is to evaluate the effects of dysmenorrhea on the development of PPD among Chinese women. A case-control study was performed on parturients who delivered from January 1, 2016, to December 31, 2016, at Bao an Maternal and Child Health Hospital in Shenzhen, China. The Edinburgh Postnatal Depression Scale (EPDS) was used to screen for maternal postpartum depression. Logistic regression models were used to examine the association between dysmenorrhea and the risk of PPD. A total of 360 women including 120 cases and 240 controls were enrolled. Our study showed that parturients with PPD had a higher percentage of dysmenorrhea than women without PPD (64.2% vs 47.9%, P = 0.004). In univariate analysis, we observed that dysmenorrhea increased the risk for PPD (OR = 1.95; 95% CI: 1.24-3.06; P = 0.004). In the fully adjusted model, dysmenorrhea was still significantly associated with an increased risk of PPD (OR = 2.45; 95% CI: 1.36-4.54; P = 0.003). Our data confirmed that dysmenorrhea may be a risk factor for PPD. Therefore, screening for postpartum depression should be considered in parturients with a history of dysmenorrhea.

Trichinella spiralis Infection Mitigates Collagen-Induced Arthritis via Programmed Death 1-Mediated Immunomodulation.

Helminth infection induces Th2-biased immune responses and inhibitory/regulatory pathways that minimize excessive inflammation to facilitate the chronic infection of helminth in the host and in the meantime, prevent host hypersensitivity from autoimmune or atopic diseases. However, the detailed molecular mechanisms behind modulation on inflammatory diseases are yet to be clarified. Programmed death 1 (PD-1) is one of the important inhibitory receptors involved in the balance of host immune responses during chronic infection. Here, we used the murine model to examine the role of PD-1 in CD4+ T cells in the effects of Trichinella spiralis infection on collagen-induced arthritis (CIA). Mice infected with T. spiralis demonstrated higher expression of PD-1 in the spleen CD4+ T cells than those without infection. Mice infected with T. spiralis 2 weeks prior to being immunized with type II collagen displayed lower arthritis incidence and significantly attenuated pathology of CIA compared with those of uninfected mice. The therapeutic effect of T. spiralis infection on CIA was reversed by blocking PD-1 with anti-PD-1 antibody, associated with enhanced Th1/Th17 pro-inflammatory responses and reduced Th2 responses. The role of PD-1 in regulating CD4+ T cell differentiation and proliferation during T. spiralis infection was further examined in PD-1 knockout (PD-1-/-) C57BL/6 J mice. Interestingly, T. spiralis-induced alteration of attenuated Th1 and enhanced Th2/regulatory T cell differentiation in wild-type (WT) mice was effectively diminished in PD-1-/- mice characterized by recovered Th1 cytokine levels, reduced levels of Th2 and regulatory cytokines and CD4+CD25+Foxp3+ cells. Moreover, T. spiralis-induced CD4+ T cell proliferation suppression in WT mice was partially restored in PD-1-/- mice. This study introduces the first evidence that PD-1 plays a critical role in helminth infection-attenuated CIA in a mouse model by regulating the CD4+ T cell function, which may provide the new insights into the mechanisms of helminth-induced immunomodulation of host autoimmunity.

Ts-Hsp70 induces protective immunity against Trichinella spiralis infection in mouse by activating dendritic cells through TLR2 and TLR4.

BACKGROUND: Trichinellosis is a serious food-borne parasitic zoonosis worldwide. In the effort to develop vaccine against Trichinella infection, we have identified Trichinella spiralis Heat shock protein 70 (Ts-Hsp70) elicits partial protective immunity against T. spiralis infection via activating dendritic cells (DCs) in our previous study. This study aims to investigate whether DCs were activated by Ts-Hsp70 through TLR2 and/or TLR4 pathways. METHODS AND FINDINGS: After blocking with anti-TLR2 and TLR4 antibodies, the binding of Ts-Hsp70 to DCs was significantly reduced. The reduced binding effects were also found in TLR2 and TLR4 knockout (TLR2-/- and TLR4-/-) DCs. The expression of TLR2 and TLR4 on DCs was upregulated after treatment with Ts-Hsp70 in vitro. These results suggest that Ts-Hsp70 is able to directly bind to TLR2 and TLR4 on the surface of mouse bone morrow-derived DCs. In addition, the expression of the co-stimulatory molecules (CD80, CD83) on Ts-Hsp70-induced DCs was reduced in TLR2-/- and TLR4-/- mice. More evidence showed that Ts-Hsp70 reduced its activation on TLR2/4 knockout DCs to subsequently activate the naïve T-cells. Furthermore, Ts-Hsp70 elicited protective immunity against T. spiralis infection was reduced in TLR2-/- and TLR4-/- mice correlating with the reduced humoral and cellular immune responses. CONCLUSION: This study demonstrates that Ts-Hsp70 activates DCs through TLR2 and TLR4, and TLR2 and TLR4 play important roles in Ts-Hsp70-induced DCs activation and immune responses.

The association between ambient temperature and preterm birth in Shenzhen, China: a distributed lag non-linear time series analysis.

BACKGROUND: A few studies have examined the association between ambient temperature and preterm birth (PTB), and the results have been inconsistent. This study explored the association between ambient temperature and PTB in Shenzhen, China. METHODS: Data of daily singleton PTB, air pollution and meteorological variables from 2005 to 2011 were collected in Shenzhen. A distributed lag non-linear model (DLNM) was used to investigate the association of the low and high temperatures (1st, 5th, 95th, and 99th percentiles) with PTB. RESULTS: The median temperature was 24.5 °C and the 1st, 5th, 95th, and 99th percentiles of daily mean temperatures were 9, 12.5, 29.9 and 30.7 °C, respectively. The prevalence of singleton PTB was 5.61 % in Shenzhen. The association between temperature and PTB was not linear. There was an immediate positive association of low temperature (1st and 5th percentiles) and a negative association of high temperature (95th and 99th percentiles) with PTB. The effect of low temperature 9 °C (1st) on PTB on the current day was stronger than that of 12.5 °C (5th), with a relative risk (RR) of 1.54 (95 % CI: 1.36-1.75) and 1.49 (95 % CI: 1.35-1.63), respectively. The cumulative RR (up to 30 days) of 9 and 12.5 °C was 1.72 (95 % CI: 1.28-2.33) and 1.96 (95 % CI: 1.60-2.39), respectively. The cumulative effects (up to 30 days) of high temperature (95th and 99th percentiles) on PTB were 0.69 (95 % CI: 0.60-0.80) and 0.62 (95 % CI: 0.52-0.74), respectively. The cumulative effect (up to 30 days) of low temperatures on vaginal delivery PTB was lower than that of the cesarean section PTB with an RR of 1.58 (95 % CI: 1.12-2.22) and 1.93 (95 % CI: 1.21-3.08), respectively. CONCLUSIONS: This study suggests that low temperature might be a risk factor, while high temperature might be a protective factor of PTB in Shenzhen.

Effect of enterohaemorrhagic Escherichia coli O157:H7-specific enterohaemolysin on interleukin-1ß production differs between human and mouse macrophages due to the different sensitivity of NLRP3 activation.

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 infection in humans can cause acute haemorrhagic colitis and severe haemolytic uraemic syndrome. The role of enterohaemolysin (Ehx) in the pathogenesis of O157:H7-mediated disease in humans remains undefined. Recent studies have revealed the importance of the inflammatory response in O157:H7 pathogenesis in humans. We previously reported that Ehx markedly induced interleukin-1ß (IL-1ß) production in human macrophages. Here, we investigated the disparity in Ehx-induced IL-1ß production between human and mouse macrophages and explored the underlying mechanism regarding the activation of NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasomes. In contrast to the effects on human differentiated THP-1 cells and peripheral blood mononuclear cells, Ehx exerted no effect on IL-1ß production in mouse macrophages and splenocytes because of a disparity in pro-IL-1ß cleavage into mature IL-1ß upon caspase-1 activation. Additionally, Ehx significantly contributed to O157:H7-induced ATP release from THP-1 cells, which was not detected in mouse macrophages. Confocal microscopy demonstrated that Ehx was a key inducer of cathepsin B release in THP-1 cells but not in mouse IC-21 cells upon O157:H7 challenge. Inhibitor experiments indicated that O157:H7-induced IL-1ß production was largely dependent upon caspase-1 activation and partially dependent upon ATP signalling and cathepsin B release, which were both involved in NLRP3 activation. Moreover, inhibition of K(+) efflux drastically diminished O157:H7-induced IL-1ß production and cytotoxicity. The findings in this study may shed light on whether and how the Ehx contributes to the development of haemolytic uraemic syndrome in human O157:H7 infection.

Excretory/secretory products from Trichinella spiralis adult worms ameliorate DSS-induced colitis in mice.

BACKGROUND: Many evidences show the inverse correlation between helminth infection and allergic or autoimmune diseases. Identification and characterization of the active helminth-derived products responsible for the beneficial effects on allergic or inflammatory diseases will provide another feasible approach to treat these diseases. METHODS AND FINDINGS: Colitis was induced in C57BL/6 mice by giving 3% DSS orally for 7 days. During this period, the mice were treated daily with the excretory/secretory products from T. spiralis adult worms (AES) intraperitoneally. The severity of colitis was monitored by measuring body weight, stool consistency or bleeding, colon length and inflammation. To determine the T. spiralis AES product-induced immunological response, Th1, Th2, Th17 and regulatory cytokine profiles were measured in lymphocytes isolated from colon, mesenteric lymph nodes (MLN), and the spleen of treated mice. The CD4+ CD25+ FOXP3+ regulatory T cells (Tregs) were also measured in the spleens and MLN of treated mice. Mice treated with AES significantly ameliorated the severity of the DSS-induced colitis indicated by the reduced disease manifestations, improved macroscopic and microscopic inflammation correlated with the up-regulation of Treg response (increased regulatory cytokines IL-10, TGF-beta and regulatory T cells) and down-regulation of pro-inflammatory cytokines (IFN-gamma, IL-6 and IL-17) in the spleens, MLN and colon of treated mice. CONCLUSIONS: Our results provide direct evidences that T. spiralis AES have a therapeutic potential for alleviating inflammatory colitis in mice. This effect is possibly mediated by the immunomodulation of regulatory T cells to produce regulatory and anti-inflammatory cytokines and inhibit pro-inflammatory cytokines.

Global transcriptional and phenotypic analyses of Escherichia coli O157:H7 strain Xuzhou21 and its pO157_Sal cured mutant.

Escherichia coli O157:H7 is an important food-borne pathogen that can cause hemorrhagic colitis and hemolytic-uremic syndrome in humans. pO157_Sal, a novel conjugative plasmid is present in a Chinese O157:H7 outbreak strain Xuzhou21. Here we investigated the phenotypic and transcriptional differences between the wild type strain Xuzhou21 and the pO157_Sal cured mutant strain Xuzhou21m. RNA-Seq analysis found that all 52 ORFs encoded on pO157_Sal were transcribed. One hundred and sixty eight chromosomal and pO157 genes were differentially expressed (≥2 fold difference) between Xuzhou21 and Xuzhou21m. Sixty-seven and 101 genes were up-regulated and down-regulated respectively by pO157_Sal including genes related to stress response, adaption and virulence. The plasmid-cured mutant Xuzhou21m grew slower than wild type Xuzhou21 and pO157_Sal plasmid complemented strain Xuzhou21c in M9 medium under the condition of high NaCl or presence of sodium deoxycholate (NaDC), corroborating with the RNA-Seq data. Seven differentially expressed genes are associated with NaDC resistance, including the adenine-specific DNA-methyltransferase gene (dam), multidrug efflux system subunit gene mdtA, hyperosmotically inducible periplasmic protein gene osmY and oxidation-reduction related genes while two differentially expressed genes (osmY and pspD) are likely to be related to resistance to osmotic pressure. A number of differentially expressed genes were virulence associated including four genes encoding T3SS effectors from the chromosome and ehxD from pO157. Through complementation of Xuzhou21m with a plasmid construct carrying the pO157_Sal hha homolog we further showed that the pO157_Sal hha represses the expression of T3SS effectors. These findings demonstrated that the plasmid pO157_Sal affects the transcription of the chromosomal and pO157 plasmid genes and contributes to the enhanced ability to resist stress. We conclude that pO157_Sal plays an important role in regulating global gene expression and affects the virulence and adaptation of E. coli O157:H7.

Contribution of silver ions to the inhibition of infectivity of Schistosoma japonicum cercariae caused by silver nanoparticles.

Blockage of pathogen transmission through water decontamination is considered an important strategy for the prevention of schistosome infection. Many believe that this strategy is feasible, but it has yet to be achieved. Silver has a long history of use as a disinfectant. With the emergence of nanotechnology, silver can be shaped into nanoparticles which have been found to possess superb antimicrobial activities. In this light, we investigated the effects of silver nanoparticles (AgNPs) on Schistosoma japonicum cercariae. AgNPs rapidly induced cercarial tail-shedding, agitated behaviour and a decrease in cercarial secretion in a dose-dependent manner. Prolonged treatment was found to be cercariocidal, which nevertheless might be attributable to AgNP-induced cercarial tail loss rather than to toxicity. Higher concentrations of AgNPs (125 µg mL-1 and above) completely blocked cercarial infectivity. Despite decreased infectivity, cercariae exposed to lower concentrations of AgNPs for 30 min were still found capable of infecting hosts even without their tails, suggesting that tail loss does not necessarily signify a total loss of infective ability. We also found that silver ions (Ag+) were heavily involved in the observed cercarial responses of AgNPs. Our observations provide insight into the interactions between the larvae of helminth parasites and nanoparticles.

Enterohemorrhagic Escherichia coli specific enterohemolysin induced IL-1ß in human macrophages and EHEC-induced IL-1ß required activation of NLRP3 inflammasome.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major foodborne pathogen causing hemorrhagic colitis and hemolytic-uremic syndrome. The role of EHEC O157:H7-enterohemolysin (Ehx) in the pathogenesis of infections remains poorly defined. In this study, we used gene deletion and complement methods to confirm its putative functions. Results demonstrated that, in THP-1 cells, EHEC O157:H7-Ehx is associated with greater production of extracellular interleukin (IL)-1ß than other cytokines. The data also showed that EHEC O157:H7-Ehx contributed to cytotoxicity in THP-1 cells, causing the release of lactate dehydrogenase (LDH). Although we observed a positive correlation between IL-1ß production and cytotoxicity in THP-1 cells infected with different EHEC O157:H7 strains, our immunoblot results showed that the majority of IL-1ß in the supernatant was mature IL-1ß and not the pro-IL-1ß that can be released after cell death. However, EHEC O157:H7-Ehx had no detectable effect on biologically inactive pro-IL-1ß at the mRNA or protein synthesis levels. Neither did it affect the expression of apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, or NOD-like receptor family pyrin domain containing 3 (NLRP3). RNA interference experiments showed that EHEC O157:H7-induced IL-1ß production required the involvement of ASC, caspase-1, and NLRP3 expression in THP-1 cells. Our results demonstrate that Ehx plays a crucial role in EHEC O157:H7-induced IL-1ß production and its cytotoxicity to THP-1 cells. NLRP3 inflammasome activation is also involved in EHEC O157:H7-stimulated IL-1ß release.

The effects of interleukin (IL)-12 and IL-4 deficiency on worm development and granuloma formation in Schistosoma japonicum-infected mice.

CD4(+) T-helper (Th) cell is widely recognized to be capable of influencing worm development and egg granuloma formation after schistosome infection. Interleukin (IL)-12 and IL-4 play key roles in regulation of Th cell differentiation. In the present study, we subcutaneously inoculated mice with hybridoma cells secreting monoclonal antibodies to neutralize IL-12 and IL-4 and explored the effects of IL-12 and IL-4 deficiency on the worm development and granuloma formation in mice infected with cercariae of Schistosoma japonicum. It was found that deficiency of host IL-12 and IL-4 supported normal parasite survival and fecundity. However, worm development (length and female fecundity) was significantly enhanced in anti-IL-12-treated mice. Mean length of worms in anti-IL-12-treated group was significantly greater than that of intact controls on day 28 after infection (females, 11.84 ± 1.20 mm vs. 9.45 ± 1.34; males, 9.35 ± 1.21 mm vs. 8.10 ± 0.85 mm, p < 0.05). Liver egg load per pair of worms (1,770.12 ± 470.67 vs. 806.08 ± 232.37, p < 0.05) and uterine egg load of ovigerous females (93.08 ± 27.85 vs. 46.05 ± 34.24, p < 0.05) in anti-IL-12-treated mice were significantly higher than those in intact control 28 days postinfection. But these effects diminished 42 days postinfection (p > 0.05). Granuloma size in anti-IL-12-treated mice was significantly larger than that in intact mice 42 days postinfection (398.3 ± 80.7 µm vs. 294.4 ± 72.2 µm, p < 0.05). Granuloma fibrosis dramatically intensified in anti-IL-12-treated mice but diminished in anti-IL-4-treated mice. The results suggest that IL-12 may play an impeditive role in the development of S. japonicum and in granuloma formation as well as fibrosis. IL-4 may promote granuloma formation but have no effect on worm development.