FTY720 ameliorates experimental MPO-ANCA-associated vasculitis by regulating fatty acid oxidation via the neutrophil PPARα-CPT1a pathway.

OBJECTIVES: Increasing studies demonstrated the importance of C5a and anti-neutrophil cytoplasmic antibody (ANCA)-induced neutrophil activation in the pathogenesis of ANCA-associated vasculitis (AAV). Sphingosine-1-phosphate (S1P) acts as a downstream effector molecule of C5a and enhances neutrophil activation induced by C5a and ANCA. The current study investigated the role of a S1P receptor modulator FTY720 in experimental autoimmune vasculitis (EAV) and explored the immunometabolism-related mechanisms of FTY720 in modulating ANCA-induced neutrophil activation. METHODS: The effects of FTY720 in EAV were evaluated by quantifying hematuria, proteinuria, crescent formation, tubulointerstitial injury and pulmonary hemorrhage. RNA sequencing of renal cortex and gene enrichment analysis were performed. The proteins of key identified pathways were analyzed in neutrophils isolated from peripheral blood of patients with active AAV and normal controls. We assessed the effects of FTY720 on ANCA-induced neutrophil respiratory burst and neutrophil extracellular traps formation (NETosis). RESULTS: FTY720 treatment significantly attenuated renal injury and pulmonary hemorrhage in EAV. RNA sequencing analyses of renal cortex demonstrated enhanced fatty acid oxidation (FAO) and peroxisome proliferators-activated receptors (PPAR) signalling in FTY720-treated rats. Compared with normal controls, patients with active AAV showed decreased FAO in neutrophils. FTY720-treated differentiated HL-60 cells showed increased expression of carnitine palmitoyltransferase 1A (CPT1a) and PPARα. Blocking or knockdown of CPT1a or PPARα in isolated human neutrophils and HL-60 cells reversed the inhibitory effects of FTY720 on ANCA-induced neutrophil respiratory burst and NETosis. CONCLUSION: FTY720 attenuated renal injury in EAV through upregulating FAO via the PPARα-CPT1a pathway in neutrophils, offering potential immunometabolic targets in AAV treatment.

Clinicopathological characteristics and gene mutations in 11 patients with lipoprotein glomerulopathy.

OBJECTIVE: Lipoprotein glomerulopathy (LPG) is a rare disorder characterized by the development of glomerular lipoprotein thrombosis. LPG exhibits familial aggregation, with mutations in the apolipoprotein E (APOE) gene identified as the leading cause of this disease. This study aimed to investigate APOE gene mutations and the clinicopathological features in eleven LPG patients. METHODS: Clinicopathological and follow-up data were obtained by extracting DNA, followed by APOE coding region sequencing analysis. This study analyzed clinical and pathological manifestations, gene mutations, treatment and prognosis. RESULTS: The mean age of the eleven patients was 33.82 years. Among them, five had a positive family history for LPG, ten presented with proteinuria, four exhibited nephrotic syndrome, and six presented with microscopic hematuria. Dyslipidemia was identified in ten patients. In all renal specimens, there was evident dilation of glomerular capillary lumens containing lipoprotein thrombi, and positive oil red O staining was observed in frozen sections of all samples. APOE gene testing revealed that one patient had no mutations, while the remaining ten patients exhibited mutations in the APOE gene, with three patients presenting with multiple mutations simultaneously. Following the confirmation of LPG diagnosis, treatment with angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) was initiated, and the disease progressed slowly. CONCLUSION: LPG is histologically characterized by lamellated lipoprotein thrombi in glomeruli, and kidney biopsy is essential for diagnosis. Mutations in the APOE gene are the leading cause of LPG. This study revealed clinicopathological characteristics and APOE gene mutations in patients with LPG, which helps us better understand the disease.

Pathogenesis of anti-neutrophil cytoplasmic antibody-associated vasculitis.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) encompasses a group of potentially life-threatening disorders characterized by necrotizing small vessel vasculitis with positive serum ANCA. To date, the pathogenesis of AAV has not been fully elucidated, but remarkable progress has been achieved in the past few decades. In this review, we summarize the mechanism of AAV. The pathogenesis of AAV involves various factors. ANCA, neutrophils, and the complement system play key roles in disease initiation and progression, forming a feedback amplification loop leading to vasculitic injury. Neutrophils activated by ANCA undergo respiratory burst and degranulation, as well as releasing neutrophils extracellular traps (NETs), thus causing damage to vascular endothelial cells. Activated neutrophils could further activate the alternative complement pathway, leading to the generation of complement 5a (C5a), which amplifies the inflammatory response by priming neutrophils for ANCA-mediated overactivation. Neutrophils stimulated with C5a and ANCA could also activate the coagulation system, generate thrombin, and subsequently cause platelet activation. These events in turn augment complement alternative pathway activation. Moreover, disturbed B-cell and T-cell immune homeostasis is also involved in disease development. In-depth investigation in pathogenesis of AAV might help to offer more effective targeted therapies.

Inhibitor of apoptosis proteins antagonist SM164 ameliorates experimental MPO-ANCA-associated vasculitis via enhancing fatty acid oxidation in neutrophils.

OBJECTIVES: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of life-threatening autoimmune diseases. Inhibitors of apoptosis proteins (IAPs) are a class of molecules engaged in cell death and inflammation, interventions of which are proven effective in a number of inflammatory diseases. Here we tested whether targeting IAPs could ameliorate AAV and explored the potential mechanism. METHODS: We collected 19 kidney specimens from patients with myeloperoxidase (MPO)-AAV to investigate the expression of IAPs. The IAP pan-inhibitor SM164 was used to treat the experimental autoimmune vasculitis (EAV) rat model of AAV. RNA sequencing of renal cortex and enrichment analysis were developed to interpret gene expression. Functional experiments were performed to investigate the role of SM164 on neutrophils and endothelial cells. RESULTS: The expression of three IAPs (cIAP1, cIAP2 and XIAP) was upregulated in kidneys of AAV patients compared with normal controls. SM164 dramatically reduced renal injury in EAV rats. Transcriptomic analysis revealed prominent alterations in fatty acid oxidation and respiratory burst following SM164 treatment. Functional studies demonstrated that SM164 inhibited neutrophil activation induced by MPO-ANCA positive IgG or serum from MPO-AAV patients, and such inhibitory effect was abolished by gene silencing or pharmacological inhibition of fatty acid oxidation. SM164 also inhibited the adhesion of neutrophils to endothelial cells with little effect on the endothelial injury induced by serum from MPO-AAV patients. CONCLUSION: Inhibition of IAPs with SM164 played a protective role in AAV through enhancing intracellular fatty acid oxidation in neutrophils.

Epidemic characteristics of Mycoplasma pneumoniae infection: a retrospective analysis of a single center in Suzhou from 2014 to 2020.

Background: Mycoplasma pneumoniae (M. Pneumoniae) is a common pathogen of respiratory tract infections, but there is still a lack of detailed investigation on the large sample of M. Pneumoniae infection in the all age population. And patients with severe M. Pneumoniae pneumonia (SMPP) still have a certain risk of death. How to identify the clinical characteristics and population of patients with SMPP as soon as possible is still an urgent problem in clinical practice. Methods: Demographic characteristics, patient clinical information, and laboratory data of 81,131 patients with respiratory tract infections (RTIs) in the Affiliated Suzhou Hospital of Nanjing Medical University from 2014 to 2020 were retrospectively collected from all patient records. The serum particle agglutination (PA) test was used to determine M. Pneumoniae infection by detecting specific antibodies. The white blood cell count, the proportion of neutrophils and lymphocytes, C-reactive protein (CRP) and lactate dehydrogenase (LDH) levels between children and adults with SMPP were compared by Student's t-test; other clinical features were analyzed by χ2 test or Fisher's exact test. Results: A total of 81,131 patients with RTIs were included, and 21,582 (26.60%) M. Pneumoniae immunoglobulin M (IgM)-positive patients were detected. From 2014 to 2020, the annual proportions of M. Pneumoniae RTIs were 23.60%, 28.18%, 38.08%, 27.05%, 23.44%, 25.26%, and 18.33%, respectively. In terms of seasonal distribution, April-June and September-November were the peak seasons of M. Pneumoniae infection each year. Children and women have a high proportion of M. Pneumoniae infection. The peak age of M. Pneumoniae infection was between 4 and 14 years old. There were 301 cases of SMPP, including 281 children and 20 adults (8 cases of pregnant women). Children and pregnant women accounted for a high proportion of SMPP. Children with SMPP had more extrapulmonary symptoms, multilobar infiltrates, and increased CRP and LDH levels compared with adults. Conclusions: M. Pneumoniae infection has seasonal, sex, and age distribution trends. Children and pregnant women accounted for a high proportion of SMPP. Extrapulmonary symptoms, multilobar infiltrates, and increased CRP and LDH levels may be helpful to identify SMPP in children than in adults.

First description of the mitogenome and phylogeny:Aedes vexansand Ochlerotatus caspius of the Tribe Aedini (Diptera: Culicidae).

Culicidae, the mosquito family, includes more than 3600 species subdivided into the subfamilies Anophelinae and Culicinae. One-third of mosquitoes belong to the Aedini tribe, which is subordinate to the subfamily Culicinae, which comprises common vectors of viral zoonoses. The tribe of Aedini is extremely diverse in morphology and geographical distribution and has high ecological and medical significance. However, knowledge about the systematics of the Aedini tribe is still limited owing to its large population and the similar morphological characteristics of its species. This study provides the first description of the complete mitochondrial (mt) genome sequence of Aedes vexans and Ochlerotatus caspius belonging to the Aedini tribe. The mt genomes of A. vexans and O. caspius are circular molecules that are 15,861 bp and 15,954 bp in size, with AT contents of 78.54% and 79.36%, respectively. Both the circular mt genomes comprise 37 functional subunits, including 13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 transfer RNA genes (tRNAs), and a control region (also known as the AT-rich region). The most common start codons are ATT/ATG, apart from cox1 (TCG) and nad5 (GTG), while TAA is the termination codon for all PCGs. All tRNAs have a typical clover leaf structure, except tRNA Ser1. Phylogenetic analysis of the concatenated, aligned amino acid sequences of the 13 PCGs showed that A. vexans gathered with Aedes sp. in a sister taxon, and O. caspius gathered with Ochlerotatus sp. in a sister taxon. The findings from the present study support the concept of monophyly of all groups, ratify the current taxonomic classification, and provide vital molecular marker resources for further studies of the taxonomy, population genetics, and systematics of the Aedini tribe.

Utility of cooling patches to prevent hand-foot syndrome caused by pegylated liposomal doxorubicin in breast cancer patients.

BACKGROUND: Pegylated liposomal doxorubicin (PLD) uses the hydrophilic layer of liposomes to reach the sweat on the skin surface or accumulate in the sweat glands, producing toxic free radicals and oxidative damage, resulting in hand-foot syndrome (HFS). Regional cooling can induce vasoconstriction to reduce the release of drugs in the limbs and reduce the accumulation of drugs in sweat glands; thus, decreasing the incidence and severity of HFS. AIM: To study the efficacy of cooling patches to prevent HFS caused by PLD in the short-term. METHODS: This is a retrospective cohort study. Female breast cancer patients (n = 101) who were treated with PLD in two breast wards at our department from February 2020 to February 2021 were enrolled in the study and were randomly divided into the cooling group (51 patients) and the control group (50 patients). Patients in the control group only received routine care, while the patients in the cooling group applied cooling patches, based on routine care, to the palm and back of the hands 15 min before chemotherapy infusion for 10 h. All patients took a corresponding dose of dexamethasone orally one day before chemotherapy, on the day of chemotherapy, and one day after chemotherapy. SPSS23.0 version was used to analyze the data in this study. The occurrence and severity of HFS was analyzed by the Mann-Whitney U test, and scores were analyzed by the Student's t test or Wilcoxon rank-sum test. A P value < 0.05 was regarded as statistically significant. RESULTS: In this study, neither group of patients developed Grade 3 HFS. In the control group, the incidence of Grade 1 HFS and Grade 2 HFS was 38% and 2%, respectively. However, in the cooling group, only one person developed Grade 1 HFS (2%), and none of the patients developed Grade 2 HFS. These findings showed that cooling patches can effectively reduce the frequency and severity of HFS (P < 0.0001) in the short-term. Before the fourth chemotherapy cycle, although general self-efficacy scale scores in the cooling group were low, they were still significantly higher than those in the control group (17.22 ± 5.16 vs 19.63 ± 6.42, P = 0.041). Compared with the control group, the mean Hand-Foot Skin Reaction and Quality of Life Questionnaire score in the cooling group was significantly lower (18.08 ± 7.01 vs 14.20 ± 7.39, P = 0.008). CONCLUSION: Cooling patches can effectively reduce the frequency and severity of HFS caused by PLD in the short-term. In addition, it may help delay the decline in patients' self-efficacy.

[The impacts of outpatient vs inpatient holistic management based on exercise training on cardiac rehabilitation efficacy among patients with chronic heart failure].

Objective: To evaluate the impacts of outpatient vs inpatient exercise training (ET) on cardiac rehabilitation efficacy among patients with chronic heart failure (CHF). Methods: Thirty six patients who were diagnosed with CHF in Beijing Rehabilitation Hospital from September 2015 to September 2018, were randomly divided into three groups: control group (n=12), outpatient ET group (n=12) and inpatient ET group (n=12). Patients in control group were treated with conventional cardiac rehabilitation without ET, patients in outpatient and inpatient ET groups were treated with holistic cardiac rehabilitation with the core of ET according to individualized exercise prescription based on cardiopulmonary exercise testing (CPET). Exercise intensity of cycle ergometer was Δ50% power above anaerobic threshold (AT), 30 min/d, 5 d/week, for 12 weeks. General information, CPET parameters, echocardiogram, 6 minute walking distance (6MWD) and quality of life (QoL) score of three groups of patients before and after treatment were recorded. Results: All patients in 3 groups finished symptom-limited CPET and patients in ET groups finished 12 weeks - ET safely without complications. Before treatment, there were no significant differences in CPET parameters, echocardiogram results, 6MWD and QoL score among 3 groups (P>0.05). After treatment, AT (ml/min, ml/(min·kg), %pred), peak oxygen uptake (VO2) (ml/min, ml/(min·kg), %pred), peak oxygen pulse(ml/beat), peak workload(W/min, %pred), left ventricular ejection fraction (LVEF) and 6MWD of patients in outpatient and inpatient ET groups were significantly higher than those of patients in control group (P<0.05), QoL score of patients in outpatient and inpatient ET groups was lower than that of patients in control group(P<0.05). To be noted, there were no obvious differences in CPET indexes, echocardiogram results, 6MWD and QoL score in patients between outpatient ET group and inpatient ET group (P>0.05). For patients in control group, there were no significant differences in above parameters before and after treatment (P>0.05). AT(ml/min, ml/(min·kg)), Peak VO2 (ml/min, ml/(min·kg), %pred), peak oxygen pulse(ml/beat, %pred), peak workload(W/min, %pred), LVEF and 6MWD of patients in outpatient and inpatient ET groups were significantly higher than those before treatment (P<0.05), QoL score of patients in outpatient and inpatient ET groups after treatment was significantly lower than that before treatment (P<0.05). Conclusion: Outpatient ET can improve the cardiopulmonary function, exercise tolerance and QoL of CHF patients, which has no significant difference compared with inpatient ET, indicating that outpatient cardiac rehabilitation, as an effective rehabilitation mode, is deserved to be applied widely.

[Effects of cardiac rehabilitation protocol centered with personalized - exercise training on further improvement of holistic function in patients with coronary heart disease after percutaneous coronary intervention].

Objective: To investigate the effects of cardiac rehabilitation protocol centered with personalized - exercise training (ET) on further improvement of holistic function in patients with stable angina after percutaneous coronary intervention (PCI). Methods: 20 patients who were diagnosed with stable angina in Beijing Rehabilitation Hospital from June 2016 to December 2019, were randomly divided into control group (n=10) and ET group (n=10). All patients were received PCI selectively. After PCI, patients in Control group were treated with conventional cardiac rehabilitation without ET; patients in ET group were treated with ET-based cardiac rehabilitation for 12 weeks. Cardiopulmonary exercise testing (CPET) parameters, echocardiogram and 6-minute walking distance (6MWD) of 2 groups of patients were recorded respectively before PCI, 2 weeks after PCI and 12 weeks after ET. Results: All patients in 2 groups finished symptom limited maximum CPET, and patients in ET group finished 12 weeks - ET safely without complications. Before PCI and 2 weeks after PCI, there were no differences in parameters including anaerobic threshold (AT), peak oxygen uptake, peak oxygen pulse, left ventricular ejection fraction (LVEF) and 6MWD between control group and ET group（P>0.05）; after 12-week treatment, AT(ml/min,ml/(min·kg)), peak oxygen uptake(ml/(min·kg)), peak oxygen pulse(ml/beat) and 6MWD of patients in ET group were higher significantly than those of patients in control group (P<0.05). In ET group, the variables including AT (ml/min、ml/(min·kg)、%pred), peak oxygen uptake(ml/min,ml/(min·kg),%pred), peak oxygen pulse (ml/beat) and 6MWD of patients after 12-week ET were significantly higher than those of patients before PCI treatment (P<0.05); notably, AT (ml/(min·kg)) and peak oxygen uptake (ml/(min·kg)) of patients in ET group were significantly higher after 12-week ET program compared with those of patients 2 weeks after PCI ( P<0.05). In Control group, AT（ml/min）and peak oxygen pulse（ml/beat）of patients after 12-week treatment were higher than those of patients before PCI ( P<0.05), but there were no difference between 2 weeks after PCI and 12-week treatment ( P>0.05). Conclusion: Personalized - exercise training after PCI could further improve the cardiac function and exercise endurance, ET - based cardiac rehabilitation is an important part of secondary prevention for patients after PCI, which needs to be widely promoted.

[Meta-analysis and trial sequential analysis of Qingjin Huatan Decoction for treating community-acquired pneumonia in elderly].

To systematically evaluate the clinical efficacy and safety of modified Qingjin Huatan Decoction in the treatment of community-acquired pneumonia in the elderly, and provide evidence-based reference for the clinical application of this prescription. Randomized controlled trials of Qingjin Huatan Decoction in the treatment of community-acquired pneumonia in the elderly were collected by searching PubMed, EMbase, Cochrane Library, CNKI, China Biomedical Literature database, VIP database and WanFang database. Outcome indicators included clinical effective rate, inflammation index, symptom improvement time, chest radiograph improvement time, hospitalization time and adverse reactions. RevMan 5.3 and Stata/IC 15.1 software were used for Meta-analysis; TSA 0.9.5.10 Beta software was used for trial sequential analysis, and GRADE profiler 3.6 was used for grade evidence quality evaluation. Thirteen studies were included finally, including 1 058 patients, 536 patients in the experimental group and 522 patients in the control group.Meta-analysis showed that, the clinical effective rate of the experimental group was significantly higher than that of the control group(RR=1.16, 95%CI[1.10, 1.21], P<0.000 01); fever time(MD=-1.32, 95%CI[-1.93,-0.71], P<0.000 1), cough time(MD=-1.95, 95%CI[-2.69,-1.21), P<0.000 01), time to rale disappearance(MD=-1.55, 95%CI[-2.37,-0.73], P=0.000 2), time to chest radiograph improvement(MD=-1.72, 95%CI[-2.98,-0.46], P=0.007), and hospitalization time(MD=-3.16, 95%CI[-4.58,-1.74], P<0.000 01) in the experimental group were significantly shorter than those in the control group. The improvement in CRP(WMD=-3.44,95%CI[-4.50,-2.38],P<0.001), WBC(WMD=-2.04,95%CI[-3.31,-0.78],P<0.01), IL-6(WMD=-4.27,95%CI[-4.62,-3.92],P<0.001), and TNF-α(WMD=-0.47,95%CI[-0.55,-0.39], P<0.001) of the experimental group was significantly better than that of the control group. There was no significant difference in PCT improvement between the two groups(WMD=-0.63, 95%CI[-1.65, 0.40], P=0.23). No serious adverse reactions occurred in both groups. Sequential analysis of the trial showed that in the studies with cumulative inclusion of clinical effective rate, the data passed the traditional threshold and TSA threshold, further confirming its clinical efficacy. GRADE evaluation showed that the evidence level was low to extremely low. Western medicine treatment combined with Qingjin Huatan Decoction may improve clinical efficiency in the treatment of community-acquired pneumonia in the elderly, improve clinical symptoms faster, reduce CRP, WBC and other inflammatory indicators, and shorten hospital stay. The level of evidence obtained in this study is low, which needs to be further verified by high-quality multi-center, randomized controlled trials.

Sphingosine-1-phosphate receptor modulator FTY720 attenuates experimental myeloperoxidase-ANCA vasculitis in a T cell-dependent manner.

Sphingosine-1-phosphate (S1P) is a pleiotropic lysosphingolipid derived from the metabolism of plasma membrane lipids. The interaction between S1P and its ubiquitously expressed G-protein-coupled receptors (S1PR1-5) is crucial in many pathophysiological processes. Emerging evidence suggested a potential role for S1P receptors in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). In the present study, we investigated the effects of three different S1P receptors modulators (FTY720, SEW2871 and TY52156) in a recognized rat model of experimental autoimmune vasculitis (EAV). The effects of treatments were evaluated with clinico-pathological parameters including hematuria, proteinuria, crescent formation, pulmonary hemorrhage, etc. In vitro functional studies were performed in a Jurkat T-cell line following stimulations of serum from myeloperoxidase-AAV patients. We found that only the FTY720 treatment significantly alleviated hematuria and proteinuria, and diminished glomerular crescent formation, renal tubulointerstitial lesions and pulmonary hemorrhage in EAV. The attenuation was accompanied by less renal T-cell infiltration, up-regulated mRNA of S1PR1 and down-regulated IL-1ß in kidneys, but not altered circulating ANCA levels, suggesting that the therapeutic effects of FTY720 were B-cell independent. Further in vitro studies demonstrated that FTY720 incubation could significantly inhibit the proliferation, adhesion, and migration, and increase apoptosis of T cells. In conclusion, the S1P modulator FTY720 could attenuate EAV through the reduction and inhibition of T cells, which might become a novel treatment of ANCA-associated vasculitis.

The expression of NOD2, NLRP3 and NLRC5 and renal injury in anti-neutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND: Nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) are intracellular sensors of pathogens and molecules from damaged cells to regulate the inflammatory response in the innate immune system. Emerging evidences suggested a potential role of NLRs in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study aimed to investigate the expression of nucleotide-binding oligomerization domain containing protein 2 (NOD2), NOD-like receptor family pyrin domain containing 3 (NLRP3) and NOD-like receptor family CARD domain containing 5 (NLRC5) in kidneys of AAV patients, and further explored their associations with clinical and pathological parameters. METHODS: Thirty-four AAV patients in active stage were recruited. Their renal specimens were processed with immunohistochemistry to assess the expression of three NLRs, and with double immunofluorescence to detect NLRs on intrinsic and infiltrating cells. Analysis of gene expression was also adopted in cultured human podocytes. The associations between expression of NLRs and clinicopathological parameters were analyzed. RESULTS: The expression of NOD2, NLRP3 and NLRC5 was significantly higher in kidneys from AAV patients than those from normal controls, minimal change disease or class IV lupus nephritis. These NLRs co-localized with podocytes and infiltrating inflammatory cells. The mean optical density of NOD2 in glomeruli was significantly higher in crescentic class than non-crescentic class, and correlated with levels of proteinuria and serum creatinine at renal biopsy. The mean optical density of NLRC5 in glomeruli was significantly higher in crescentic class than non-crescentic class, and correlated with proteinuria level, Birmingham Vasculitis Activity Score and the proportion of crescents in the renal specimen. CONCLUSIONS: The expression of three NLRs was upregulated in kidneys of AAV patients. The expression of NOD2 and NLRC5 was associated with the severity of renal lesions in AAV.

Thrombin Contributes to Anti-myeloperoxidase Antibody Positive IgG-Mediated Glomerular Endothelial Cells Activation Through SphK1-S1P-S1PR3 Signaling.

Background: Activation of coagulation system plays an important role in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) pathogenesis. Thrombin, generated during coagulation could disrupt endothelial barrier integrity through protease-activated receptor 1 (PAR1). Our previous study found that sphingosine-1-phosphate (S1P) contributed to myeloperoxidase (MPO)-ANCA-positive IgG-induced glomerular endothelial cell (GEnC) activation through a S1P receptor (S1PR)-dependent route. In recent years, S1P signaling was reported to be involved in thrombin effects on endothelial cells. This current study investigated whether the interaction between thrombin-PAR and S1P-S1PR signaling contributed to MPO-ANCA-positive IgG-induced GEnC dysfunction. Methods: The effect of thrombin on GEnC activation was analyzed from three aspects. First, morphological alteration of GEnCs was observed. Second, permeability assay was performed to determine GEnC monolayer activation quantitatively. Third, endothelin-1 (ET-1) levels were measured. Expression levels of sphingosine kinases (SphKs) and S1PRs were detected. In addition, antagonists of PAR1 and S1PR3 were employed to determine their roles. Eventually, PAR1 and tissue factor (TF) expression levels as well as TF procoagulant activity were analyzed. Results: Thrombin induced further damage of tight junction, increase in endothelial monolayer permeability as well as upregulation of ET-1 levels in GEnCs stimulated with MPO-ANCA-positive IgG. Blocking PAR1 downregulated ET-1 levels in the supernatants of GEnCs treated by thrombin plus MPO-ANCA-positive IgG. Expression levels of SphK1, S1PR3 increased significantly in GEnCs treated with thrombin plus MPO-ANCA-positive IgG. S1P upregulated PAR1 and TF expression, and enhanced procoagulant activity of TF in MPO-ANCA-positive IgG-stimulated GEnCs. Conclusion: Thrombin synergized with SphK1-S1P-S1PR3 signaling pathway to enhance MPO-ANCA-positive IgG-mediated GEnC activation.

Regulatory effects of paeoniflorin-6'-O-benzene sulfonate (CP-25) on dendritic cells maturation and activation via PGE2-EP4 signaling in adjuvant-induced arthritic rats.

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease. Dendritic cells (DCs) are one of the most powerful antigen-presenting cells, and they play an important role in RA pathogenesis. Prostaglandin E2 (PGE2) is a potent lipid mediator that can regulate the maturation and activation of DCs, but the molecular mechanisms have not been elucidated. In this study, both in vitro and in an RA rat model, we investigated the mechanisms involved by focusing on PGE2-mediated signaling and using a novel anti-inflammatory compound, paeoniflorin-6'-O-benzene sulfonate (CP-25). PGE2 combined with tumor necrosis factor-α promoted DC maturation and activation through EP4-cAMP signaling. Treatment with CP-25 increased the endocytic capacity of DCs induced by PGE2. CP-25 inhibited the potency of DCs induced by the EP4 receptor agonist, CAY10598, to stimulate allogeneic T cells. Consistent with these findings, the CAY10598-induced upregulation of DC surface activation markers and production of IL-23 was significantly inhibited by CP-25 in a concentration-dependent manner. In vivo administration of CP-25 alleviated adjuvant arthritis (AA) in rats through inhibition of DC maturation and activation. Our results indicate that PGE2-EP4-cAMP signal hyperfunction can lead to abnormal activation of DC functions, which correlates with the course of disease in AA rats and provides a possible treatment target. The inhibition of DC maturation and activation by CP-25 interference of the PGE2-EP4 pathway may significantly contribute to the immunoregulatory profile of CP-25 when used to treat RA and other immune cell-mediated disorders.

CP-25 reverses prostaglandin E4 receptor desensitization-induced fibroblast-like synoviocyte dysfunction via the G protein-coupled receptor kinase 2 in autoimmune arthritis.

Paeoniflorin-6'-O-benzene sulfonate (CP-25) is a novel compound derived from paeoniflorin that has been demonstrated to have therapeutic effects in a rat model of rheumatoid arthritis (RA). However, the underlying mechanism has not been elucidated to date. We explored this mechanism in the present study by treating rats with adjuvant arthritis (AA) with CP-25. We found that the membrane EP4 protein level was downregulated; whereas, GRK2 was upregulated, in fibroblast-like synoviocyte (FLS)s of AA rats. Prostaglandin (PGE)2 stimulated FLS proliferation and enhanced the membrane EP4 receptor protein level; the latter was reversed by the administration of an EP4 receptor agonist, whereas the membrane GRK2 protein level gradually increased. The changes in the EP4 receptor and GRK2 expression were enhanced by TNF-α, and the former was accompanied by an alteration in the cyclic (c)AMP level. The EP4 receptor agonist stimulation increased the association between GRK2 and the EP4 receptor. GRK2 knockdown abrogated the abnormalities in FLS proliferation. The CP-25 treatment (100 mg/kg) suppressed joint inflammation with an efficacy that was similar to that of methotrexate. This finding was associated with EP4 upregulation and GRK2 downregulation in FLSs. Thus, GRK2 plays an important role in the abnormal FLS proliferation observed in AA possibly by promoting EP4 receptor desensitization and decreasing the cAMP level. Our results demonstrate that CP-25 has therapeutic potential for the treatment of human RA via GRK2 regulation.

Rho GTPases are involved in S1P-enhanced glomerular endothelial cells activation with anti-myeloperoxidase antibody positive IgG.

Sphingosine-1-phosphate (S1P) is a crucial regulator in vascular inflammation. Our recent study found that under pathophysiological concentration in active anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), S1P participated in MPO-ANCA-positive IgG-induced glomerular endothelial cell (GEnC) activation via a S1P receptor (S1PR)-dependent way. However, the downstream signalling pathways are not fully clear yet. In this study, we demonstrated that Rho guanosine triphosphatases (GTPases) signalling pathways, RhoA and Rac1 in particular, were implicated in MPO-ANCA-positive IgG-mediated GEnCs activation enhanced by pathophysiological concentration of S1P in AAV. These results provide mechanistic insights into vascular barrier dysfunction in AAV, which may facilitate the development of effective therapies.

Sphingosine-1-phosphate (S1P) enhances glomerular endothelial cells activation mediated by anti-myeloperoxidase antibody-positive IgG.

Cumulating evidences suggested an important role of sphingosine-1-phosphate (S1P) and its receptors in regulating endothelial barrier integrity. Our previous study revealed that the circulating S1P levels and renal expression of S1PRs correlated with disease activity and renal damage in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study investigated the role of S1P and its receptors in myeloperoxidase (MPO)-ANCA-positive IgG-mediated glomerular endothelial cell (GEnC) activation. The effect of S1P on morphological alteration of GEnCs in the presence of MPO-ANCA-positive IgG was observed. Permeability assay was performed to determine endothelial monolayer activation in quantity. Both membrane-bound and soluble ICAM-1 and VCAM-1 levels were measured. Furthermore, antagonists and/or agonists of various S1PRs were employed to determine the role of different S1PRs. S1P enhanced MPO-ANCA-positive IgG-induced disruption of tight junction and disorganization of cytoskeleton in GEnCs. S1P induced further increase in monolayer permeability of GEnC monolayers in the presence of MPO-ANCA-positive IgG. S1P enhanced MPO-ANCA-positive IgG-induced membrane-bound and soluble ICAM-1/VCAM-1 up-regulation of GEnCs. Soluble ICAM-1 levels in the supernatants of GEnCs stimulated by S1P and MPO-ANCA-positive IgG increased upon pre-incubation of S1PR1 antagonist, while pre-incubation of GEnCs with the S1PR1 agonist down-regulated sICAM-1 level. Blocking S1PR2-4 reduced sICAM-1 levels in the supernatants of GEnCs stimulated by S1P and MPO-ANCA-positive IgG. Pre-incubation with S1PR5 agonist could increase sICAM-1 level in the supernatants of GEnC stimulated by S1P and MPO-ANCA-positive IgG. S1P can enhance MPO-ANCA-positive IgG-mediated GEnC activation through S1PR2-5.

Sphingosine-1-phosphate and its receptors in anti-neutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND: C5a plays a crucial role in anti-neutrophil cytoplasmic antibody (ANCA)-mediated neutrophil recruitment and activation. Our previous studies found that the interaction between sphingosine-1-phosphate (S1P) and C5a plays an important role in the ANCA-mediated activation of neutrophils. In the current study, the expression levels of S1P in plasma and its receptors (S1PR1-5) in kidneys were analysed in patients with ANCA-associated vasculitis (AAV). METHODS: Plasma samples from 32 AAV patients in active stage and 20 AAV patients in remission were collected. The plasma levels of S1P were determined by an enzyme-linked immunosorbent assay (ELISA). The expression of S1PR1-5 in the renal specimens from 24 AAV patients was detected by immunohistochemistry. The associations of the plasma levels of S1P and renal expression of S1PRs with clinical and pathological parameters were analysed. RESULTS: The level of plasma S1P was significantly higher in AAV patients in active stage than it was in both patients in remission and in normal controls. Correlation analysis showed that the plasma levels of S1P correlated with the initial serum creatinine levels (r = 0.502, P = 0.003) and inversely correlated with the estimated glomerular filtration rate (eGFR; r = -0.358, P = 0.044) in AAV patients. Double-labelling immunofluorescence assay suggested that S1PR1-5 were expressed on endothelial cells in the glomeruli and that S1PR1, 4 and 5 were expressed on neutrophils. CONCLUSIONS: In AAV patients, the circulating S1P levels were elevated and the renal expression of S1PR2-5 was upregulated. The levels of circulating S1P and the renal expression of S1PR were associated with the renal involvement and disease activity of AAV.

Minocycline ameliorates D-galactose-induced memory deficits and loss of Arc/Arg3.1 expression.

Dysfunction of learning and memory is widely found in many neurological diseases. Understanding how to preserve the normal function of learning and memory will be extremely beneficial for the treatment of these diseases. However, the possible protective effect of minocycline in memory impairment is unknown. We used the well-established D-galactose rat amnesia model and two behavioral tasks, the Morris water maze and the step-down task, for memory evaluation. Western blot and PCR were used to examine the protein and mRNA levels of Arc/Arg3.1. We report that minocycline supplementation ameliorates both the spatial and fear memory deficits caused by D-galactose. We also found that Arc/Arg3.1, c-fos, and brain-derived neurotrophic factor levels are decreased in the D-galactose animal model, and that minocycline reverses the protein and mRNA levels of Arc in the hippocampus, suggesting the potential role of Arc/Arg3.1 in minocycline's neuroprotective mechanism. Our study strongly suggests that minocycline can be used as a novel treatment for memory impairment in neurological diseases.