Molecular screening of Entamoeba spp. (E. histolytica, E. dispar, E. coli, and E. hartmanni) and Giardia intestinalis using PCR and sequencing

A wide range of intestinal protozoan parasites inhabit the human gut. To establish a more comprehensive molecular screening, we designed PCR-sequencing screening methods for Entamoeba spp., including commensal species, and Giardia intestinalis, and performed such methods using 174 stool samples collected from Kenyan children. The prevalences of the target species were as follows: E. histolytica (2/174, 1.1%), E. dispar (20/174, 11.5%), E. coli (107/174, 61.5%), E. hartmanni (77/174, 44.3%), and G. intestinalis (54/174, 31.0%). PCR amplicons specific to G. intestinalis was differentiated to assemblages A (8/174, 4.6%) and B (46/174, 26.4%). PCR specificity for Entamoeba spp. was quite high, except for some cross-reactions between E. hartmanni detection primers and G. intestinalis, although the false-positive amplicons were discernible by the band size. The 18S rRNA PCR primers that was designed by Monis et al. in 1999 for G. intestinalis, have specificity issue, therefore amplicon sequencing was essential not only to determine assemblage classifications but also to confirm the positive results by eliminating potential non-specific reactions. The detection sensitivity of both the Entamoeba universal PCR and the G. intestinalis PCR was more than 100 copies of the target loci, which is sufficient for detecting a single trophozoite or cyst of both species.

[Bioinformatics analysis and prokaryotic expression of Strongyloides stercoralis serine protease inhibitor 1]

OBJECTIVE

To predict the structure and antigenic epitope of the Strongyloides stercoralis serine protease inhibitor 1 (Ss-SRPN-1) protein using bioinformatics tools, and to construct prokaryotic expression plasmids for expression of recombinant Ss-SRPN-1 protein, so as to provide the basis for unraveling the function of the Ss-SRPN-1 protein.

METHODS

The amino acid sequence of the Ss-SRPN-1 protein was downloaded from the NCBI database, and the physicochemical properties, structure and antigenic epitopes of the Ss-SRPN-1 protein were predicted using bioinformatics tools, including ExPASy, SWISS-MODEL and Protean. Primers were designed according to the nucleotide sequences of Ss-SRPN-1, and the Ss-SRPN-1 gene was amplified, cloned and sequenced with genomic DNA extracted from the infective third-stage larvae of S. stercoralis as a template. The Ss-SRPN-1 protein sequence was cloned into the pET28a (+) expression vector and transformed into Escherichia coli BL21 (DE) cells for induction of the recombinant Ss-SRPN-1 protein expression. The recombinant Ss-SRPN-1 protein was then purified and identified using Western blotting and mass spectrometry.

RESULTS

Bioinformatics analysis showed that the Ss-SRPN-1 protein, which was composed of 372 amino acids and had a molecular formula of C₁₉₄₈H₃₀₄₆N₄₈₈O₅₇₅S₁₆, was a stable hydrophilic protein, and the subcellular localization of the protein was predicted to be extracellular. The Ss-SRPN-1 protein was predicted to contain 11 dominant B-cell antigenic epitopes and 20 T-cell antigenic epitopes. The Ss-SRPN-1 gene with a length of 1 119 bp was successfully amplified, and the recombinant plasmid pET28a (+)/Ss-SRPN-1 was constructed and transformed into E. coli BL21(DE) cells. The expressed recombinant Ss-SRPN-1 protein had a molecular weight of approximately 43 kDa, and was characterized as a Ss-SRPN-1 protein.

CONCLUSIONS

The recombinant Ss-SRPN-1 protein has been expressed successfully, and this recombinant protein may be a potential vaccine candidate against strongyloidiasis.

Integrated Control of Fatty Acid Metabolism in Heart Failure

Disrupted fatty acid metabolism is one of the most important metabolic features in heart failure. The heart obtains energy from fatty acids via oxidation. However, heart failure results in markedly decreased fatty acid oxidation and is accompanied by the accumulation of excess lipid moieties that lead to cardiac lipotoxicity. Herein, we summarized and discussed the current understanding of the integrated regulation of fatty acid metabolism (including fatty acid uptake, lipogenesis, lipolysis, and fatty acid oxidation) in the pathogenesis of heart failure. The functions of many enzymes and regulatory factors in fatty acid homeostasis were characterized. We reviewed their contributions to the development of heart failure and highlighted potential targets that may serve as promising new therapeutic strategies.

[Expression of CD47 and its ligands in pregnant mice infected with Toxoplasma gondii during pregnancy]

OBJECTIVE

To investigate the dynamic expression of cluster of differentiation 47 (CD47) and its ligands signaling regulatory protein α (SIRPα) and thrombospondin-1 (TSP-1) in mice infected with Toxoplasma gondii in the second and third trimesters.

METHODS

C57BL/6J mice (6 to 8 weeks old) were used for modeling T. gondii infection in the first trimester, and the pregnant mice were randomly divided into the normal control and infection groups, of 10 mice in each group. Pregnant mice in the infection group were intraperitoneally injected with 150 T. gondii tachyzoites on gestational day (Gd) 6.5, while pregnant mice in the normal control group were intraperitoneally injected with the same volume of physiological saline at the same time. The uterine and placental specimens were collected from all pregnant mice on Gd12.5 and Gd18.5, and the pregnant outcomes were recorded. The pathological damages of mouse uterine and placental specimens were observed using hematoxylin-eosin (HE) staining on Gd12.5 and Gd18.5. The relative expression of CD47, SIRPα, TSP-1, surface antigen 1 (SAG1), interferon-γ (IFN-γ), interleukin-2 (IL-2), IL-4 and IL-13 mRNA was quantified in mouse uterine and placental specimens using real-time fluorescence quantitative PCR (qPCR) assay, and the CD47, SIRPα, TSP-1 expression was determined in mouse uterine and placental specimens using immunohistochemical staining.

RESULTS

As compared with those in the normal control group, the pregnant mice in the infection group showed back arching, bristling, trembling and listlessness during pregnancy, and several mice presented virginal bleeding and abortion. Pathological examinations showed inflammatory cell infiltration, congestion and necrosis in uterine and placental specimens of pregnant mice in the infection group, a higher abortion rate of pregnant mice was seen in the infection group than in the normal control group on Gd12.5 (χ² = 20.405, P < 0.001) and Gd18.5 (χ² = 28.644, P < 0.001). qPCR assay showed significant differences in the expression of CD47, SIRPα, TSP-1, SAG1, INF-γ, IL-2, IL-4 and IL-13 genes in mouse placental specimens between the normal control and infection groups on Gd12.5 and Gd18.5 [F' (F) = 37.511, 29.337, 97.343, 53.755, 67.188, 21.145, 8.658 and 13.930, all P values < 0.001]. Higher CD47, SIRPα and TSP-1 gene expression was quantified in mouse placental specimens in the infection group than in the normal control group on Gd12.5 (all P values < 0.01), and lower CD47, SIRPα and TSP-1 gene expression was quantified in the infection group than in the normal control group on Gd18.5 (all P values < 0.001), while higher SAG1 gene expression was detected in placental specimens of pregnant mice in the infection group than in the normal control group on Gd12.5 and Gd18.5 (both P values < 0.01). In addition, higher INF-γ and IL-2 expression and lower IL-4 and IL-13 expression was detected in mouse placental specimens in the infection group than in the normal control group on Gd12.5 and Gd18.5 (all P values < 0.001), and there were significant differences in the CD47, SIRPα, TSP-1, SAG1, INF-γ, IL-2, IL-4 and IL-13 gene expression in uterine specimens of pregnant mice between the normal control and infection groups on Gd12.5 and Gd18.5 [H(F' and F) = 14.951, 25.977, 18.711, 48.595, 39.318, 14.248 and 15.468, all P values < 0.01], and higher CD47 and TSP-1 expression was detected in mouse uterine specimens in the infection group than in the control group on Gd12.5 and Gd18.5 (all P values < 0.01); however, no significant difference was found in the SIRPα expression (P > 0.05). Higher SAG1 expression was detected in uterine specimens of pregnant mice in the infection group than in the normal control group on Gd12.5 and Gd18.5 (both P values < 0.01), and higher INF-γ and IL-2 gene expression and lower IL-4 and IL-13 gene expression was found in the placental specimens of pregnant mice in the infection group than in the normal control group on Gd12.5 and Gd18.5 (all P values < 0.001). Spearman correlation analysis showed that the CD47 gene expression correlated positively with IFN-γ (r_s = 0.735, P < 0.05) and IL-2 (r_s = 0.655, P < 0.05) and negatively with IL-4 (r_s = -0.689, P < 0.05) and IL-13 expression (r_s = -0.795, P < 0.05) in the placental specimens of pregnant mice in the infection group on Gd12.5, and the CD47 gene expression correlated negatively with IFN-γ (r_s = -0.745, P < 0.05) and IL-2 expression (r_s = -0.816, P < 0.05) and positively with IL-4 (r_s = 0.704, P < 0.05) and IL-13 (r_s = 0.802, P < 0.05) in the placental specimens of pregnant mice in the infection group on Gd18.5. Immunohistochemical staining showed mild CD47, SIRPα and TSP-1 expression in uterine and placental specimens of pregnant mice in the normal control group on Gd12.5 and Gd18.5, strong CD47, SIRPα and TSP-1 expression in the placental specimens of pregnant mice in the infection group on Gd12.5 and strong CD47 and TSP-1 expression in the uterine specimens of pregnant mice in the infection group on Gd12.5.

CONCLUSIONS

T. gondii infection in the first trimester may cause abnormal expression of CD47 and its ligands SIRPα and TSP-1 in the maternal-fetal interface of pregnant mice in the second and third trimesters, which may be associated with the immune escape of T. gondii at the maternal-fetal interface.

Dendritic cell-mediated chronic low-grade inflammation is regulated by the RAGE-TLR4-PKCβ1 signaling pathway in diabetic atherosclerosis

Background

The unique mechanism of diabetic atherosclerosis has been a central research focus. Previous literature has reported that the inflammatory response mediated by dendritic cells (DCs) plays a vital role in the progression of atherosclerosis. The objective of the study was to explore the role of DCs in diabetes mellitus complicated by atherosclerosis.

Methods

ApoE^−/− mice and bone marrow-derived DCs were used for in vivo and in vitro experiments, respectively. Masson’s staining and Oil-red-O staining were performed for atherosclerotic lesion assessment. The content of macrophages and DCs in plaque was visualized by immunohistochemistry. The expression of CD83 and CD86 were detected by flow cytometry. The fluctuations in the RNA levels of cytokines, chemokines, chemokine receptors and adhesions were analyzed by quantitative RT-PCR. The concentrations of IFN-γ and TNF-α were calculated using ELISA kits and the proteins were detected using western blot. Coimmunoprecipitation was used to detect protein–protein interactions.

Results

Compared with the ApoE^−/− group, the volume of atherosclerotic plaques in the aortic root of diabetic ApoE^−/− mice was significantly increased, numbers of macrophages and DCs were increased, and the collagen content in plaques decreased. The expression of CD83 and CD86 were significantly upregulated in splenic CD11c⁺ DCs derived from mice with hyperglycemia. Increased secretion of cytokines, chemokines, chemokine receptors, intercellular cell adhesion molecule (ICAM), and vascular cell adhesion molecule (VCAM) also were observed. The stimulation of advanced glycation end products plus oxidized low-density lipoprotein, in cultured BMDCs, further activated toll-like receptor 4, protein kinase C and receptor of AGEs, and induced immune maturation of DCs through the RAGE-TLR4-PKCβ₁ signaling pathway that was bound together by intrinsic structures on the cell membrane. Administering LY333531 significantly increased the body weight of diabetic ApoE^−/− mice, inhibited the immune maturation of spleen DCs, and reduced atherosclerotic plaques in diabetic ApoE^−/− mice. Furthermore, the number of DCs and macrophages in atherosclerotic plaques was significantly reduced in the LY333531 group, and the collagen content was increased.

Conclusions

Diabetes mellitus aggravates chronic inflammation, and promotes atherosclerotic plaques in conjunction with hyperlipidemia, which at least in part through inducing the immune maturation of DCs, and its possible mechanism of action is through the RAGE-TLR4-pPKCβ₁ signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00431-6.

iPLA2β Contributes to ER Stress-Induced Apoptosis during Myocardial Ischemia/Reperfusion Injury

Both calcium-independent phospholipase A2 beta (iPLA2β) and endoplasmic reticulum (ER) stress regulate important pathophysiological processes including inflammation, calcium homeostasis and apoptosis. However, their roles in ischemic heart disease are poorly understood. Here, we show that the expression of iPLA2β is increased during myocardial ischemia/reperfusion (I/R) injury, concomitant with the induction of ER stress and the upregulation of cell death. We further show that the levels of iPLA2β in serum collected from acute myocardial infarction (AMI) patients and in samples collected from both in vivo and in vitro I/R injury models are significantly elevated. Further, iPLA2β knockout mice and siRNA mediated iPLA2β knockdown are employed to evaluate the ER stress and cell apoptosis during I/R injury. Additionally, cell surface protein biotinylation and immunofluorescence assays are used to trace and locate iPLA2β. Our data demonstrate the increase of iPLA2β augments ER stress and enhances cardiomyocyte apoptosis during I/R injury in vitro and in vivo. Inhibition of iPLA2β ameliorates ER stress and decreases cell death. Mechanistically, iPLA2β promotes ER stress and apoptosis by translocating to ER upon myocardial I/R injury. Together, our study suggests iPLA2β contributes to ER stress-induced apoptosis during myocardial I/R injury, which may serve as a potential therapeutic target against ischemic heart disease.

Identification of differentially expressed genes in the endothelial precursor cells of patients with type 2 diabetes mellitus by bioinformatics analysis

Type 2 diabetes mellitus (DM) is a metabolic disease with worldwide prevalence that is associated with a decrease in the number and function of endothelial progenitor cells (EPCs). The aim of the present study was to explore the potential hub genes of EPCs in patients with type 2 DM. Differentially expressed genes (DEGs) were screened from a public microarray dataset (accession no. GSE43950). Pathway and functional enrichment analyses were performed using the Database for Annotation, Visualization and Integrated Discovery. The protein-protein interaction (PPI) network was visualized. The most significantly clustered modules and hub genes were identified using Cytoscape. Furthermore, hub genes were validated by quantitative PCR analysis of EPCs isolated from diabetic and normal subjects. Subsequently, weighted gene co-expression network analysis (WGCNA) was performed to identify the modules incorporating the genes exhibiting the most significant variance. A total of 970 DEGs were obtained and they were mainly accumulated in inflammation-associated pathways. A total of 9 hub genes were extracted from the PPI network and the highest differential expression was determined for the interleukin 8 (IL8) and CXC chemokine ligand 1 (CXCL1) genes. In the WGCNA performed to determine the modules associated with type 2 DM, one module incorporated IL8 and CXCL1. Finally, pathway enrichment of 10% genes in the pink module ordered by intramodular connectivity (IC) was associated with the IL17 and the chemokine signaling pathways. The present results revealed that the expression of IL8 and CXCL1 may serve important roles in the pathophysiology of EPCs during type 2 DM and inflammatory response may be critical for the reduced number and hypofunction of EPCs isolated from patients with diabetes.

GRP78 (Glucose-Regulated Protein of 78 kDa) Promotes Cardiomyocyte Growth Through Activation of GATA4 (GATA-Binding Protein 4)

The heart manifests hypertrophic growth in response to elevation of afterload pressure. Cardiac myocyte growth involves new protein synthesis and membrane expansion, of which a number of cellular quality control machineries are stimulated to maintain function and homeostasis. The unfolded protein response is potently induced during cardiac hypertrophy to enhance protein-folding capacity and eliminate terminally misfolded proteins. However, whether the unfolded protein response directly regulates cardiac myocyte growth remains to be fully determined. Here, we show that GRP78 (glucose-regulated protein of 78 kDa)-an endoplasmic reticulum-resident chaperone and a critical unfolded protein response regulator-is induced by cardiac hypertrophy. Importantly, overexpression of GRP78 in cardiomyocytes is sufficient to potentiate hypertrophic stimulus-triggered growth. At the in vivo level, TG (transgenic) hearts overexpressing GRP78 mount elevated hypertrophic growth in response to pressure overload. We went further to show that GRP78 increases GATA4 (GATA-binding protein 4) level, which may stimulate Anf (atrial natriuretic factor) expression and promote cardiac hypertrophic growth. Silencing of GATA4 in cultured neonatal rat ventricular myocytes significantly diminishes GRP78-mediated growth response. Our results, therefore, reveal that protein-folding chaperone GRP78 may directly enhance cardiomyocyte growth by stimulating cardiac-specific transcriptional factor GATA4.

Cerebral Venous Thrombosis: MR Black-Blood Thrombus Imaging with Enhanced Blood Signal Suppression

BACKGROUND AND PURPOSE

The residual blood flow artifact is a critical confounder for MR black-blood thrombus imaging of cerebral venous sinus thrombosis. This study aimed to conduct a validation of a new MR black-blood thrombus imaging technique with enhanced blood signal suppression.

MATERIALS AND METHODS

Twenty-six participants (13 volunteers and 13 patients) underwent conventional imaging methods followed by 2 randomized black-blood thrombus imaging scans, with a preoptimized delay alternating with nutation for tailored excitation (DANTE) preparation switched on and off, respectively. The signal intensity of residual blood, thrombus, brain parenchyma, normal lumen, and noise on black-blood thrombus images were measured. The thrombus volume, SNR of residual blood, and contrast-to-noise ratio for residual blood versus normal lumen, thrombus versus residual blood, and brain parenchyma versus normal lumen were compared between the 2 black-blood thrombus imaging techniques. Segmental diagnosis of venous sinus thrombosis was evaluated for each black-blood thrombus imaging technique using a combination of conventional imaging techniques as a reference.

RESULTS

In the volunteer group, the SNR of residual blood (11.3 ± 2.9 versus 54.0 ± 23.4, P < .001) and residual blood-to-normal lumen contrast-to-noise ratio (7.5 ± 3.4 versus 49.2 ± 23.3, P < .001) were significantly reduced using the DANTE preparation. In the patient group, the SNR of residual blood (16.4 ± 8.0 versus 75.0 ± 35.1, P = .002) and residual blood-to-normal lumen contrast-to-noise ratio (12.4 ± 7.8 versus 68.8 ± 35.4, P = .002) were also significantly lower on DANTE-prepared black-blood thrombus imaging. The new black-blood thrombus imaging technique provided higher thrombus-to-residual blood contrast-to-noise ratio, significantly lower thrombus volume, and substantially improved diagnostic specificity and agreement with conventional imaging methods.

CONCLUSIONS

DANTE-prepared black-blood thrombus imaging is a reliable MR imaging technique for diagnosing cerebral venous sinus thrombosis.

[The protective effect of pigment epithelial-derived factor modified human umbilical cord mesenchymal stem cells on rats with diabetic retinopathy]

Objective: To investigate the effect of pigment epithelial-derived factor (PEDF) gene-modified human umbilical cord mesenchymal stem cells (MSC) on rats with diabetic retinopathy (DR). Methods: Experimental study. Human umbilical cord MSC were transfected by lentivirus packaging PEDF-MSC-green fluorescent protein (GFP) and GFP-MSC plasmid vectors, and the expression of PEDF and vascular endothelial growth factor (VEGF) was measured in the cell culture medium. Fifty adult male Sprague-Dawley rats were randomly divided into five groups: normal control group (group A), DR control group (group B), phosphate-buffered saline (PBS) treated group (group C), GFP-MSC treated group (group D) and PEDF-MSC-GFP treated group (group E), with 10 rats in each group. Streptozotocin was intraperitoneally injected to make early DR models. After four-month intervention, groups D and E were given intravitreal injection of GFP-MSC and PEDF-MSC-GFP; group C was given intravitreal injection of phosphate-buffered saline; groups A and B did not receive special treatment. The changes of retina in different groups were detected by hematoxylin and eosin staining, and the thickness of inner plexiform layer, inner nuclear layer and outer nuclear layer was measured by computer-based image analytical system. Immunohistochemistry was applied to observe PEDF and VEGF. Real-time quantitative polymerase chain reaction was used to detect the expression of PEDF and VEGF mRNA. Results: The expression of CD105, CD73 and CD90 was positive, while the expression of CD34, CD45, CD11b, CD19 and HLA-DR was negative. ELISA results showed that after transfection PEDF protein expression in the supernatant of PEDF-MSC (84.09±7.07) μg/L was higher than the control group (9.03±0.14) μg/L (P<0.05). At 2 weeks after intravitreal injection, green fluorescence was observed in the rat vitreous of groups D and E under a fluorescence microscope; no obvious green fluorescence was found in the retina. After 2 months of intravitreal injection, the thickness of inner plexiform layer in group E was significantly decreased; the thickness of inner nuclear layer and outer nuclear layer was higher (P<0.05). Immunohistochemical staining showed that 2 months after intravitreal treatment, the average optical density values of PEDF were improved, but the average optical density values of VEGF were decreased in group E (P<0.05). Real-time polymerase chain reaction showed that 2 months after treatment, the expression level of PEDF mRNA in group E was improved, but the expression level of VEGF mRNA was decreased (P<0.05). Conclusions: Intravitreal injection of PEDF-MSC could up-regulate the expression of PEDF and down-regulate the expression of VEGF in diabetic rats and may represent a novel candidate resource for cell therapy of DR nerve damage. (Chin J Ophthalmol, 2017, 53, 540-547).

Clinical, neuroimaging and prognostic study of 127 cases with infarction of the corpus callosum

Background and purpose

The aim of this study was to retrospectively investigate clinical and neuroimaging characteristics in the largest sample size of patients with corpus callosum infarction to date and then to follow up these patients for 1 year to clarify the prognosis of this rare stroke entity.

Methods

A total of 127 patients with acute callosal infarction out of 5584 acute ischaemic stroke patients were included in this study. The recruited patients were divided into a pure callosal infarction group and a complex callosal infarction group (coupled with other infarct locations simultaneously), and clinical and neuroimaging features were analyzed. Some of the patients were followed up for 1 year to evaluate recurrence rate and mortality.

Results

The incidence of acute callosal infarction was 2.3%. Most patients presented with advanced neurological dysfunction with or without mild to moderate motor or sensory disorders on admission. The negative rate of computed tomography scan was still 76.4% even at >24 h after onset. Large‐artery atherosclerosis was the most common etiological type. Compared with complex callosal infarction, the pure callosal infarction group had more mental disorders (P = 0.030). Compared with common basal ganglia infarction, the pure callosal infarction group had better short‐term recovery (P = 0.016) but higher 1‐year mortality (P = 0.037). Age and mental disorders were independent risk factors for death in callosal infarction.

Conclusions

Callosal infarction is a white matter stroke that occurs with low incidence. Elderly patients with vascular risk factors showed sudden mental or cognitive disorders and callosal infarction could not be excluded. More attention should be paid to the early diagnosis and secondary prevention of callosal infarction because of its poor long‐term outcome.

[Reliability and validity of the Chinese version on Comprehensive Scores for Financial Toxicity based on the patient-reported outcome measures]

Objective: To evaluate the reliability and validity of the Chinese version on comprehensive scores for financial toxicity (COST), based on the patient-reported outcome measures. Methods: A total of 118 cancer patients were face-to-face interviewed by well-trained investigators. Cronbach's α and Pearson correlation coefficient were used to evaluate reliability. Content validity index (CVI) and exploratory factor analysis (EFA) were used to evaluate the content validity and construct validity, respectively. Results: The Cronbach's α coefficient appeared as 0.889 for the whole questionnaire, with the results of test-retest were between 0.77 and 0.98. Scale-content validity index (S-CVI) appeared as 0.82, with item-content validity index (I-CVI) between 0.83 and 1.00. Two components were extracted from the Exploratory factor analysis, with cumulative rate as 68.04% and loading>0.60 on every item. Conclusion: The Chinese version of COST scale showed high reliability and good validity, thus can be applied to assess the financial situation in cancer patients.

Thymosin β4 promotes glucose-impaired endothelial progenitor cell function via Akt/endothelial nitric oxide synthesis signaling pathway

Circulating endothelial progenitor cells (EPCs) are a subtype of hematopoietic stem cells, which can differentiate into endothelial cells and restore endothelial function. However, high glucose decreases the number and impairs the function of EPCs. A previous study showed that thymosin β4 (Tβ4), a pleiotropic peptide beneficial for multiple functions of various types of cells, could promote EPC migration and dose-dependently upregulate the phosphorylation of Akt and endothelial nitric oxide synthesis signaling (eNOS). In present study, the hypothesis that Tβ4 can improve glucose-suppressed EPC functions via the Akt/eNOS signaling pathway and restores the production of nitric oxide (NO) is investigated. EPCs were isolated from the peripheral blood of healthy volunteers and formed a cobblestone shape after 3–4 weeks of cultivation. Then, EPCs were treated with high concentrations of glucose (25 mM) for 4 days and administrated with Tβ4 for further study. Transwell migration and tube formation assays were performed to access the migratory and angiogenic ability of EPCs. In addition, the quantity of Akt, eNOS and the concentration of nitric oxide (NO) was investigated. Functional studies showed that high concentrations of glucose significantly suppressed EPC function, while this adverse effect was reversed by the administration of Tβ4. In addition, Akt small interfering (si)RNA and eNOS siRNA were demonstrated to reduce the protective effect of Tβ4 against glucose-impaired EPC functions. These findings suggest that Tβ4 improves glucose-impaired EPC functions via the Akt/eNOS signaling pathway.

Thymosin β4 promotes endothelial progenitor cell angiogenesis via a vascular endothelial growth factor‑dependent mechanism

Endothelial progenitor cells (EPCs) are a promising cell source for tissue repair and regeneration, predominantly through angiogenesis promotion. Paracrine functions serve a pivotal role in EPC‑mediated angiogenesis, which may be impaired by various cardiovascular risk factors. Therefore, it is important to identify a solution that optimizes the paracrine function of EPCs. Thymosin β4 (Tβ4) is a peptide with the potential to promote tissue regeneration and wound healing. A previous study demonstrated that Tβ4 enhances the EPC‑mediated angiogenesis of the ischemic myocardium. In the present study, whether Tβ4 improved angiogenesis by enhancing the paracrine effects of EPCs was investigated. A tube formation assay was used to assess the effect of angiogenesis, and the paracrine effects were measured using an ELISA kit. The results indicated that Tβ4 improved the paracrine effects of EPCs, evidenced by an increase in the expression of vascular endothelial growth factor (VEGF). EPC‑conditioned medium (EPC‑CM) significantly promoted human umbilical vein endothelial cell angiogenesis in vitro, which was further enhanced by pretreatment with Tβ4. The effect of Tβ4 pretreated EPC‑CM on angiogenesis was abolished by VEGF neutralizing antibody in vitro, indicating that increased VEGF secretion had a pivotal role in Tβ4‑mediated EPC angiogenesis. Furthermore, transplantation of EPCs pretreated with Tβ4 into infarcted rat hearts resulted in significantly higher VEGF expression in the border zone, compared with EPC transplantation alone. To further investigate whether the Akt/eNOS pathway was involved in Tβ4‑induced VEGF secretion in EPCs, the expression levels of VEGF in EPC‑CM were significantly decreased following knockdown of Akt or eNOS by small interfering RNA transfection. In conclusion, Tβ4 significantly increased angiogenesis by enhancing the paracrine effects of EPCs, evidenced by the increased expression of VEGF. The RAC‑α serine/threonine‑protein kinase/endothelial nitric oxide synthase signal transduction pathway was involved in the regulation of Tβ4‑induced VEGF secretion in EPCs. Further studies are required to investigate the long‑term prognosis of patients with coronary heart disease following Tβ4‑pretreated EPC transplantation.

Endoplasmic Reticulum Chaperone GRP78 Protects Heart From Ischemia/Reperfusion Injury Through Akt Activation

RATIONALE

Restoration of coronary artery blood flow is the most effective means of ameliorating myocardial damage triggered by ischemic heart disease. However, coronary reperfusion elicits an increment of additional injury to the myocardium. Accumulating evidence indicates that the unfolded protein response (UPR) in cardiomyocytes is activated by ischemia/reperfusion (I/R) injury. Xbp1s (spliced X-box binding protein 1), the most highly conserved branch of the unfolded protein response, is protective in response to cardiac I/R injury. GRP78 (78 kDa glucose-regulated protein), a master regulator of the UPR and an Xbp1s target, is upregulated after I/R. However, its role in the protective response of Xbp1s during I/R remains largely undefined.

OBJECTIVE

To elucidate the role of GRP78 in the cardiomyocyte response to I/R using both in vitro and in vivo approaches.

METHODS AND RESULTS

Simulated I/R injury to cultured neonatal rat ventricular myocytes induced apoptotic cell death and strong activation of the UPR and GRP78. Overexpression of GRP78 in neonatal rat ventricular myocytes significantly protected myocytes from I/R-induced cell death. Furthermore, cardiomyocyte-specific overexpression of GRP78 ameliorated I/R damage to the heart in vivo. Exploration of underlying mechanisms revealed that GRP78 mitigates cellular damage by suppressing the accumulation of reactive oxygen species. We go on to show that the GRP78-mediated cytoprotective response involves plasma membrane translocation of GRP78 and interaction with PI3 kinase, culminating in stimulation of Akt. This response is required as inhibition of the Akt pathway significantly blunted the antioxidant activity and cardioprotective effects of GRP78.

CONCLUSIONS

I/R induction of GRP78 in cardiomyocytes stimulates Akt signaling and protects against oxidative stress, which together protect cells from I/R damage.

Glucose-regulated protein 78 is essential for cardiac myocyte survival

Secretory and transmembrane proteins rely on proper function of the secretory pathway for folding, posttranslational modification, assembly, and secretion. Accumulation of misfolded proteins in the endoplasmic reticulum (ER) stimulates the unfolded protein response (UPR), which communicates between the ER and other organelles to enhance ER-folding capacity and restore cellular homeostasis. Glucose-regulated protein of 78 kDa (GRP78), an ER-resident protein chaperone, is a master regulator of all UPR signaling branches. Accumulating studies have established a fundamental role of GRP78 in protein folding, ER stress response, and cell survival. However, role of GRP78 in the heart remains incompletely characterized. Here we showed that embryos lacking GRP78 specifically in cardiac myocytes manifest cardiovascular malformations and die in utero at late gestation. We went further to show that inducible knockout of GRP78 in adult cardiac myocytes causes early mortality due to cardiac cell death and severe decline in heart performance. At the cellular level, we found that loss of GRP78 increases apoptotic cell death, which is accompanied by reduction in AKT signaling and augmentation of production for reactive oxygen species. Importantly, enhancing AKT phosphorylation and activity leads to decreases in oxidative stress and increases in cardiac myocyte survival. Collectively, our results demonstrate an essential role of GRP78 in ensuring normal cardiogenesis and maintaining cardiac contractility and function.

Apelin Ameliorates High Glucose-Induced Downregulation of Connexin 43 via AMPK-Dependent Pathway in Neonatal Rat Cardiomyocytes

Diabetes Mellitus is a common disorder, with increasing risk of cardiac arrhythmias. Studies have shown that altered connexin expression and gap junction remodeling under hyperglycemia contribute to the high prevalence of cardiac arrhythmias and even sudden death. Connexin 43 (Cx43), a major protein that assembles to form cardiac gap junctions, has been found to be downregulated under high glucose conditions, along with inhibition of gap junctional intercellular communication (GJIC). While, apelin, a beneficial adipokine, increases Cx43 protein expression in mouse and human embryonic stem cells during cardiac differentiation. However, it remains unknown whether apelin influences GJIC capacity in cardiomyocytes. Here, using Western blotting and dye transfer assays, we found that Cx43 protein expression was reduced and GJIC was impaired after treatment with high glucose, which, however, could be abrogated after apelin treatment for 48 h. We also found that apelin increased Cx43 expression under normal glucose. Real-time PCR showed that the Cx43 mRNA was not significantly affected under high glucose conditions in the presence of apelin or high glucose and apelin. High glucose decreased the phosphorylation of AMPKα; however, apelin activated AMPKα. Interestingly, we found that Cx43 expression was increased after treatment with AICAR, an activator of AMPK signaling. AMPKα inhibition mediated with transfection of siRNA-AMPKα1 and siRNA-AMPKα2 abolished the protective effect of apelin on Cx43 expression. Our data suggest that apelin attenuates high glucose-induced Cx43 downregulation and improves the loss of functional gap junctions partly through the AMPK pathway.

CCAAT enhancer binding protein β promotes tumor growth and inhibits apoptosis in prostate cancer by methylating estrogen receptor β

The CCAAT enhancer binding protein β (C/EBPβ) is overexpressed at late stages in carcinogenesis of prostate cancer (PCa), suggesting that it could potentially contribute to progression of PCa. Estrogen receptor beta (ERβ) is a tumor suppressor gene in PCa. However, whether C/EBPβ could regulate ERβ by promoter methylation is still poorly understood.In this study, expression levels of C/EBPβ and ERβ in two PC lines (LNCap and PC-3), prostatic epithelial cell line (RWPE-1), forty-eight paired non-cancerous and cancerous peripheral blood samples were examined via qRT-PCR, western blotting and methylation-specific PCR. In addition, PCa cell line was infected with pCDH-C/EBPβ and pLKO.1-C/EBPβ and expression levels of C/EBPβ, ERβ and DNA methyltransferases were detected. Finally, the role of C/EBPβ in proliferation and apoptosis of PCa cell lines was examined by MTT and flow cytometer assay. Our results show a higher frequency of promoter methylation of ERβ levels in blood samples from PCa patients (16 of 48 cases) compared with that from healthy controls (3 of 48). Besides, elevated expression levels of C/EBPβ were found in PCa patients and two PCa lines (LNCap and PC-3) compared to non-cancerous cases or prostatic epithelial cell line (RWPE-1), while opposite expression levels of ERβ were found. Overexpression of C/EBPβ could regulate ERβ expression, DNA methyltransferases expression, cell proliferation and apoptosis. Our results support the conclusion that C/EBPβ down-regulated ERβ expression through increasing its promoter methylation, and then regulated proliferation and apoptosis in PCa.

[The protective effect of human umbilical cord mesenchymal stem cells-induced neural stem cells in the vitreous on the blood-retinal barrier in diabetic rats]

Objective: To investigate the effect of intravitreal injection of neural stem cells (NSC) induced from human umbilical cord mesenchymal stem cells, and to provide a theoretical basis for the clinical treatment of blood-retinal barrier damage due to diabetic retinopathy (DR). Methods: Experimental study. Sixty male Sprague-Dawley rats were randomly divided into control group, DR group and NSC group. Diabetic rats were induced by injection of streptozotocin, and the control rats were injected with an equal volume of solvent. Three months after the establishment of diabetic models, the NSC group was injected with 2 μl of NSC in the right vitreous, and the DR group was injected with 2 μl of phosphate-buffered saline. One month later, all the rats were sacrificed. The retinal vessels and leakage were examined with flat-mounted retinas. Vascular permeability was quantified by analyzing albumin leakage using the Evans blue (EB) method. Retina was examined by hematoxylin and eosin staining. Results: Retinal blood vessels of the control rats were normal, with no EB leakage outside the vessels. The background fluorescence was enhanced and focal leakage and focal dilated vessels were detected in the DR group. In the NSC group, background fluorescence was enhanced slightly and EB leakage area decreased significantly compared with the DR group. The average EB in control group, DR group and NSC group were (9.91±1.53), (24.67±2.26) and (12.85±2.58)μg/g, The EB leakage in the NSC group decreased significantly compared with the DR group (q=9.748, P<0.05). Pathological hematoxylin and eosin staining showed that the retinal layer structure was normal and clear in the control group, the retina was thin, the cell arrangement was in disorder and the nucleus was swelling in the DR group, the status of the NSC group was between the other two groups. Conclusions: Transferring human umbilical cord mesenchymal stem cells-induced NSC in vitro to diabetic rat models by intravitreal injection could reduce leakage of blood vessels and attenuate blood-retinal barrier breakdown induced by diabetes. (Chin J Ophthalmol, 2017, 53: 53-58).

The Impact of Rosuvastatin on the Density Score of Coronary Artery Calcification in Coronary Artery Disease Patients with Type 2 Diabetes Mellitus: Rationale and Design of RosCal Study

INTRODUCTION

More and more evidence suggests that the density of calcification plays an important role in the plaque stability. However, few studies have investigated the statin treatment on the density of plaque calcification in patients with both coronary artery disease (CAD) and type 2 diabetes mellitus.

METHODS

One hundred and twenty-two CAD patients with type 2 diabetes with confirmed coronary artery calcification (CAC) will be recruited consecutively in a 12-month period. These patients will receive rosuvastatin (20 mg/day) therapy in the next 24 months. Blood tests and adverse events will be collected at routine follow-up of 1, 3, 6, 12, 18 and 24 months. The primary endpoint will be the change of CAC density score measured by coronary CT angiography after 24 months' treatment of rosuvastatin (20 mg/day) compared with baseline. The secondary endpoints will be the change of serum sclerostin and the effect on the volume score of CAC in those patients.

RESULTS

We expect that rosuvastatin could both increase the density of CAC to improve plaque stability and up-regulate serum sclerostin, which would suggest the underlying mechanism of the plaque stabilization by a statin.

CONCLUSION

This study would be the first to demonstrate the impact of rosuvastatin on the density score of coronary artery calcification in CAD patients with type 2 diabetes. This study has been registered in ClinicalTrials.gov (NCT02418884).

NADPH oxidase activation played a critical role in the oxidative stress process in stable coronary artery disease

OBJECTIVES

The study was designed to investigate the oxidative stress levels of endothelial progenitor cells (EPCs) in stable coronary artery disease (CAD) and to explore the underlying mechanisms of NADPH oxidase activation and subsequent EPCs dysfunction.

METHODS

EPCs were isolated from patients with stable CAD (n=50) and matched healthy volunteers (n=50). NADPH oxidase activation was detected by measuring the expression of each subunit using western blotting and qPCR analyses and the membrane translocation of p47^phox using immunofluorescence. The in vivo angiogenesis capacity was evaluated using immunofluorescence by transplanting EPCs into a rat hind limb ischemia model. The PKC inhibitor GÖ-6983 was used to determine the role of PKC in NADPH oxidase activation.

RESULTS

Oxidative stress level was increased and the in vivo angiogenesis capacity was impaired in EPCs obtained from CAD subjects with the activation of NADPH oxidase. P47^phox membrane translocation increased in CAD group vs controls. These effects were resolved by NADPH oxidase inhibition. Up-regulation of PKCα/β2 was found in EPCs from CAD subjects, PKC inhibition GÖ-6983 could reduce the expression and activity of NADPH oxidation.

CONCLUSIONS

NADPH oxidase activation via p47^phox membrane translocation played a critical role in the initiation and progression of CAD, and the PKCα/β2 signaling pathway might be involved.

Resveratrol prevents endothelial progenitor cells from senescence and reduces the oxidative reaction via PPAR‑γ/HO‑1 pathways

Increasing evidence suggests endothelial progenitor cells (EPCs) improve neovascularization and endothelium regeneration. Resveratrol (RSV) is a natural polyphenolic compound, which has been demonstrated to exert multiple protective effects on the cardiovascular system, including inhibition of platelet adhesion and aggregation, reduction of myocardial ischemia-reperfusion injury, and suppression of neointimal hyperplasia of injured vascular tissue. The present study investigated the role of RSV on levels of oxidative stress and senescence of EPCs, and the effects of RSV on vascular-promoting and/or vascular-healing capacity of EPCs. It was demonstrated that EPCs could promote the repair of endothelium of the injured artery. RSV reduced the oxidative reaction of EPCs and inhibited EPC senescence, and these effects may occur via the peroxisome proliferator-activated receptor-γ/heme oxygenase-1 signaling pathways.

Activation of liver X receptor attenuates lysophosphatidylcholine-induced IL-8 expression in endothelial cells via the NF-κB pathway and SUMOylation

The liver X receptor (LXR) is a cholesterol‐sensing nuclear receptor that has an established function in lipid metabolism; however, its role in inflammation is elusive. In this study, we showed that the LXR agonist GW3965 exhibited potent anti‐inflammatory activity by suppressing the firm adhesion of monocytes to endothelial cells. To further address the mechanisms underlying the inhibition of inflammatory cell infiltration, we evaluated the effects of LXR agonist on interleukin‐8 (IL‐8) secretion and nuclear factor‐kappa B (NF‐κB) activation in human umbilical vein endothelial cells (HUVECs). The LXR agonist significantly inhibited lysophosphatidylcholine (LPC)‐induced IL‐8 production in a dose‐dependent manner without appreciable cytotoxicity. Western blotting and the NF‐κB transcription activity assay showed that the LXR agonist inhibited p65 binding to the IL‐8 promoter in LPC‐stimulated HUVECs. Interestingly, knockdown of the indispensable small ubiquitin‐like modifier (SUMO) ligases Ubc9 and Histone deacetylase 4 (HDAC4) reversed the increase in IL‐8 induced by LPC. Furthermore, the LPC‐induced degradation of inhibitory κBα was delayed under the conditions of deficient SUMOylation or the treatment of LXR agonist. After enhancing SUMOylation by knockdown SUMO‐specific protease Sentrin‐specific protease 1 (SENP1), the inhibition of GW3965 was rescued on LPC‐mediated IL‐8 expression. These findings indicate that LXR‐mediated inflammatory gene repression correlates to the suppression of NF‐κB pathway and SUMOylation. Our results suggest that LXR agonist exerts the anti‐atherosclerotic role by attenuation of the NF‐κB pathway in endothelial cells.

[The normative values of vestibular evoked myogenic potentialin different age-groups]

Objective:To obtain the normative values of vestibular evoked myogenic potential(VEMP),i.e.the threshold,latency,latency-interval,amplitude of healthy population in Tianjin medical university General hospital.These values will help clinical diagnosis.Method:Seventy-five healthy individuals (39 males and 36 females,age from 21 to 70 years)were enrolled in this study.They were divided into 3 groups according to age:group 1(21-30 years),group 2(>30-50 years),group 3(>50-70 years).oVEMP and cVEMP were performed and the normative values were obtained.SPSS 19.0 was used to analyze the data.Result:The response rate was 77.3% and 85.3% of oVEMP and cVEMP respectively in all subjects.The values of oVEMP:in group 1 response rate was 100%,amplitude was(8.29±1.25)μV and threshold value was(83.65±4.10) dBnHL.In group 2 response rate was 85.4%,amplitude was(6.32±1.21)μV and threshold value was(89.24±4.18) dBnHL.In group 3 response rate was 46%,amplitude was(4.26±1.20) μV,threshold value was(95.13±4.21) dBnHL.The values of cVEMP: in group 1 response rate was 100%,amplitude was(108.87±19.10)μV and threshold value was(84.54±4.35) dBnHL.In group 2 response rate was 83.3%,amplitude was(84.10±20.02)μV and threshold value was (90.33±4.29)dBnHL.In group 3 response rate was 72.0%,amplitude was(64.18±19.22)μV and threshold value was (95.19±4.30)dBnHL.The statistical analysis show significant difference in oVEMP/cVEMP response rate,threshold and amplitude among different age-groups(P<0.05).No significant difference was found in N1,P1 latency and latency-interval among different age-groups(P>0.05).Conclusion:The normative values of VEMP of healthy population in Tianjin medical university General hospital were obtained in this research.These VEMP data were used for the diagnosis of related diseases.

Effect of different luteal support schemes on clinical outcome in frozen-thawed embryos transfer cycles

OBJECTIVE

To evaluate the clinical outcome of frozen-thawed embryo transfer (FET) when using different luteal support schemes.

STUDY DESIGN

Retrospective analysis of FET cycles was performed from June 2013 and December 2013. Infertile women, who underwent FET cycles utilizing embryos cryopreserved on day 3 post-insemination following an initial fresh IVF cycle. Patients were divided into three groups according to the luteal support scheme. Grade A (oral administration of progesterone, n=156), Group B (vaginal administration of progesterone, n=345), Group C (dissolved progesterone in oil with intramuscular infection, n=885), and group C was divided into two subgroups according to with (subgroup Cl, n=521) or without (subgroup C2 ,n=364) human chorionic gonadotrophi (hCG) injected intramuscularly. The authors compared patients' characteristics and the pregnancy outcomes of each group.

RESULTS

There was no difference in the patient characteristics of each group. There was no difference in the implantation rate or clinical and ongoing pregnancy rate among oral, vaginal, and intramuscular progesterone groups. The abortion and ectopic pregnancy rates were not significantly different among the three groups.

CONCLUSION

Oral progesterone in the FET cycles is convenient and has similar pregnancy outcomes compared with intramuscular or vaginal administration.

Shear stress regulates endothelial cell autophagy via redox regulation and Sirt1 expression

Disturbed cell autophagy is found in various cardiovascular disease conditions. Biomechanical stimuli induced by laminar blood flow have important protective actions against the development of various vascular diseases. However, the impacts and underlying mechanisms of shear stress on the autophagic process in vascular endothelial cells (ECs) are not entirely understood. Here we investigated the impacts of shear stress on autophagy in human vascular ECs. We found that shear stress induced by laminar flow, but not that by oscillatory or low-magnitude flow, promoted autophagy. Time-course analysis and flow cessation experiments confirmed that this effect was not a transient adaptive stress response but appeared to be a sustained physiological action. Flow had no effect on the mammalian target of rapamycin-ULK pathway, whereas it significantly upregulated Sirt1 expression. Inhibition of Sirt1 blunted shear stress-induced autophagy. Overexpression of wild-type Sirt1, but not the deacetylase-dead mutant, was sufficient to induce autophagy in ECs. Using both of gain- and loss-of-function experiments, we showed that Sirt1-dependent activation of FoxO1 was critical in mediating shear stress-induced autophagy. Shear stress also induced deacetylation of Atg5 and Atg7. Moreover, shear stress-induced Sirt1 expression and autophagy were redox dependent, whereas Sirt1 might act as a redox-sensitive transducer mediating reactive oxygen species-elicited autophagy. Functionally, we demonstrated that flow-conditioned cells are more resistant to oxidant-induced cell injury, and this cytoprotective effect was abolished after inhibition of autophagy. In summary, these results suggest that Sirt1-mediated autophagy in ECs may be a novel mechanism by which laminar flow produces its vascular-protective actions.

Parallel enzyme-linked immunosorbent assay screening for human immunodeficiency virus among blood donors in five Chinese blood centres: a retrospective analysis

AIMS

To evaluate the strategy of parallel screening with different enzyme-linked immunosorbent assays (ELISA) among Chinese blood donors.

BACKGROUND

Parallel screening with ELISA has been the main strategy to detect human immunodeficiency virus (HIV) in blood donations in China for more than a decade. The performance of the strategy should be analysed.

METHODS

A total of 821,927 donations collected from five Chinese blood centres in 2008-2010 were tested using two third-generation ELISAs by different manufacturers licenced and confirmed by the Western blot (WB) in this study. The confirmatory positive predictive values (PPV), false positive rates (FPR), false negative rates (FNR) and potential risks for transfusion resulting from single or sequential ELISA screening were evaluated.

RESULTS

A total of 5318 (0·647%) of donations screened HIV reactive and were discarded. WB confirmatory results on 1668 available samples suggested that PPVs for dual ELISA, one round ELISA reactive and grey zone samples were 75·1, 0·7 and 0·5%, respectively. Eight out of 1124 one round ELISA reactive and 1 out of 195 grey zone samples were WB confirmed positive. All but one ELISA assay displayed comparable PPVs but variable FPRs and FNRs that differed by blood centre.

CONCLUSIONS

In the absence of nucleic acid testing (NAT), parallel ELISA screening prevented a substantial number of HIV infected donations from entering the Chinese blood supply. However, the loss of false positive donors should be re-evaluated especially given the frequently reported blood supply shortage in China.