Core fucosylation and its roles in gastrointestinal glycoimmunology

Glycosylation is a common post-translational modification in eukaryotic cells. It is involved in the production of many biologically active glycoproteins and the regulation of protein structure and function. Core fucosylation plays a vital role in the immune response. Most immune system molecules are core fucosylated glycoproteins such as complements, cluster differentiation antigens, immunoglobulins, cytokines, major histocompatibility complex molecules, adhesion molecules, and immune molecule synthesis-related transcription factors. These core fucosylated glycoproteins play important roles in antigen recognition and clearance, cell adhesion, lymphocyte activation, apoptosis, signal transduction, and endocytosis. Core fucosylation is dominated by fucosyltransferase 8 (Fut8), which catalyzes the addition of α-1,6-fucose to the innermost GlcNAc residue of N-glycans. Fut8 is involved in humoral, cellular, and mucosal immunity. Tumor immunology is associated with aberrant core fucosylation. Here, we summarize the roles and potential modulatory mechanisms of Fut8 in various immune processes of the gastrointestinal system.

CXCL1-CXCR2 signalling mediates hypertensive retinopathy by inducing macrophage infiltration

Inflammation plays an important role in hypertensive retinal vascular injury and subsequent retinopathy. Monocyte chemotaxis via CXCL1-CXCR2 binding has been implicated in various cardiovascular diseases, but the function of CXCL1-CXCR2 signalling involved in retinopathy, which was investigated as angiotensin II (Ang II)-induced retinopathy, is unclear. In our study, we established a hypertensive retinopathy (HR) model by Ang II infusion (3000 ng/min/kg) for 3 weeks. To determine the involvement of CXCR2 signalling, we used CXCR2 knockout (KO) mice or C57BL/6J wild-type (WT) mice as experimental subjects. The mice were treated with a CXCL1 neutralizing antibody or SB225002 (the specific CXCR2 inhibitor). Our results showed that after Ang II treatment, the mRNA levels of CXCL1 and CXCR2 and the number of CXCR2⁺ inflammatory cells were significantly elevated. Conversely, unlike in the IgG control group, the CXCL1 neutralizing antibody greatly reduced the increase in central retinal thickness induced by Ang II infusion, arteriolar remodelling, superoxide production, and retinal dysfunction in WT mice. Furthermore, Ang II infusion induced arteriolar remodelling, infiltration of Iba1⁺ macrophages, the production of oxidative stress, and retinal dysfunction, but the symptoms were ameliorated in CXCR2 KO mice and SB225002-treated mice. These protective effects were related to the reduction in the number of CXCR2⁺ immune cells, particularly macrophages, and the decrease in proinflammatory cytokine (IL-1β, IL-6, TNF-ɑ, and MCP-1) expression in Ang II-treated retinas. Notably, serum CXCL1 levels and the number of CXCR2⁺ monocytes/neutrophils were higher in HR patients than in healthy controls. In conclusion, this study provides new evidence that the CXCL1-CXCR2 axis plays a vital role in the pathogenesis of hypertensive retinopathy, and selective blockade of CXCL1-CXCR2 activation may be a potential treatment for HR.

[Influential factors for failure of enhanced recovery after surgery from hepatectomy for hepatocellular carcinoma and the establishment of risk prediction model]

Objective: To investigate the influential factors for failure of enhanced recovery after surgery(ERAS) from hepatectomy for hepatocellular carcinoma(HCC) patients and then to establish a risk prediction model. Methods: The relevant clinical data of 180 patients with HCC undergoing hepatectomy at Department of Hepatic Surgery, Affiliated Provincial Hospital, Anhui Medical University from January 2016 to June 2017 were analyzed retrospectively.There were 149 male patients and 31 female patients aging of (56.5±11.0)years(from 33 to 84 years old). The factors affecting postoperative failure of ERAS of HCC patients were identified by univariate and multivariate analyses, and then, all the obtained factors and their statistical values were used to establish the risk prediction model. Results: A total of 23 patients failed in the ERAS protocol(12.8%). The preoperative total bilirubin (TBIL), alanine aminotransferase(ALT) and amount of intraoperative bleeding were independent risk factors for failure of ERAS from hepatectomy(all P<0.05). The obtained risk prediction model was presented as follows: risk coefficient(R)=0.114×(TBIL)+ 0.082×(ALT)+ 0.008×(amount of intraoperative bleeding). At the cut of value of R=7.90, the area under the ROC curve of this model for predicting failure of ERAS was 0.866(95%CI: 0.788-0.945, P<0.01), with the sensitivity and specificity of 69.6% and 91.1%, respectively.External validation results indicated that the scoring system had good differential ability(area under the ROC curve=0.889, 95%CI: 0.811-0.967, P<0.01). Conclusions: Higher level of preoperative TBIL(>21 μmol/L) and ALT(>50 U/L) and the larger amount of intraoperative bleeding (more than 400 ml) are independent risk factors for failure of ERAS inpatients undergoing hepatectomy for HCC and the established prediction model may have certain value for risk assessment.

RETRACTED: Role of fractalkine/CX3CR1 signaling pathway in the recovery of neurological function after early ischemic stroke in a rat model

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the authors and Editor-in-Chief. Concern was raised about the reliability of the Western blot results, as detailed here: https://pubpeer.com/publications/7BB8F6559AF31100A59484E5D97802; and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. In addition, a portion of Figure 5A, CA3 ‘Positive control’ group appears to contain image similarities with Figure 5A, CA1 ‘CX3CR1 inhibitor’ group. The journal requested that the corresponding author comment on these concerns and provide the raw data. However, the authors were not able to satisfactorily fulfill this request and therefore the Editor-in-Chief decided to retract the article.

Protective effect of cyclophilin A against Alzheimer's amyloid beta-peptide (25-35)-induced oxidative stress in PC12 cells

BACKGROUND

beta-amyloid peptide (Abeta) is considered responsible for the pathogenesis of Alzheimer's disease (AD). Possible mechanisms underlying Abeta-induced neuronal cytotoxicity include excessive production of reactive oxidative species (ROS) and apoptosis. Cyclophilin A (CypA), exhibits antioxidant properties and protects neurons against oxidative stress induced injury. This study was conducted to demonstrate whether CyPA added to cultured PC12 cells could alleviate Abeta-induced oxidative stress and protect them from apoptosis.

METHODS

PC12 cells were pre-incubated for 30 minutes with recombinant human cyclophilin A (rhCyPA) in 0.1 nmol/L, 1.0 nmol/L, 10 nmol/L and 100 nmol/L and then incubated with 10 micromol/L Abeta(25-35). In every group, cell viability, apoptotic morphology, apoptotic rate, intracellular ROS accumulation, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) of PC12 cells and mitochondrial transmembrane potential were detected. Subsequently, the expression of the active form of caspase-3 was determined by Western blotting.

RESULTS

It was shown that cultures treated with 1.0 nmol/L, 10 nmol/L or 100 nmol/L rhCyPA + Abeta(25-35) had significantly higher cell viability and a lower rate of apoptosis compared with the cultures exposed only to Abeta(25-35). In addition, rhCyPA attenuated Abeta(25-35)-induced overproduction of intracellular ROS and Abeta(25-35)-induced a decrease in activity of the key antioxidant enzymes SOD and GSH-Px. Furthermore, rhCyPA also attenuated Abeta(25-35)-induced mitochondrial dysfunction and the activation of caspase-3.

CONCLUSION

CyPA may act as an ROS scavenger, and prevent Abeta(25-35)-induced neurotoxicity through attenuating oxidative stress induced by Abeta(25-35).

Study on the performance of anaerobic ammonium oxidation treatment using PVA gel as a carrier

A continuous experiment was carried out to study the performance of anaerobic ammonium oxidation (anammox), a novel and low cost nitrogen removal treatment process with an energy-saving characteristic. A complete mixing reactor was used with polyvinyl alcohol (PVA) gel as the carrier. In particular, performances of nitrogen removal and attachment characteristics of anammox bacteria on the PVA carrier surface were investigated. The results indicted that high concentration of anammox bacteria, up to 27,000 mg/L-carrier, had attached on the PVA carrier surface. A high nitrogen removal rate of up to 5.5 kg/m(3)-reactor/d was obtained during this continuous experiment. Furthermore, it was also confirmed that there was no generation of N(2)O gas in the anammox reaction.