[Bioinformatics analysis of the RNA binding protein DDX39 of Toxoplasma gondii]

OBJECTIVE

To analyze the RNA binding protein of Toxoplasma gondii (TgDDX39) using bioinformatics technology, and to evaluate the immunogenicity of TgDDX39, so as to provide insights into development of toxoplasmosis vaccines.

METHODS

The amino acid sequences of TgDDX39 were retrieved from the ToxoDB database, and the physicochemical properties, transmembrane structure domain, signal peptide sites, post-translational modification sites, coils, secondary and tertiary structures, hydrophobicity, and antigenic epitopes of the TgDDX39 protein were predicted using online bioinformatics tools, incluiding ProtParam, TMHMM 2.0, SignalP 5.0, NetPhos 3.1, COILS, SOPMA, Phyre2, ProtScale, ABCpred, SYFPEITHI and DNA-STAR.

RESULTS

TgDDX39 protein was predicted to be an unstable hydrophilic protein with the molecular formula of C2173H3458N598O661S18, which contained 434 amino acids and had an estimated molecular weight of 49.1 kDa and a theoretical isoelectric point of 5.55. The protein was predicted to have an extremely low possibility of signal peptides, without transmembrane regions, and contain 27 phosphorylation sites. The β turn and random coils accounted for 39.63% of the secondary structure of the TgDDX39 protein, and a coiled helix tended to produce in one site. In addition, the TgDDX39 protein contained multiple B and T cell antigenic epitopes.

CONCLUSIONS

Bioinformatics analyses predict that TgDDX39 protein has high immunogenicity and contains multiple antigenic epitopes. TgDDX39 protein is a potential candidate antigen for vaccine development.

Stereotactic Radiotherapy or Whole Brain Radiotherapy Combined with Pyrotinib and Capecitabine in HER2-Positive Advanced Breast Cancer Patients with Brain Metastases (BROPTIMA): A Prospective, Phase Ib/II Single-Arm Clinical Study

PURPOSE/OBJECTIVE(S)

Approximately half of patients with advanced HER2-positive breast cancer (BC) will develop brain metastases (BM) over time. Local therapy including stereotactic radiotherapy (SRT) and whole brain radiotherapy (WBRT) is the main initial treatment in malignant tumor patients with BM. However, more than 50% patients after radiotherapy in one year suffered intracranial recurrence. Pyrotinib, a small molecule, irreversible, pan-ErbB receptor tyrosine kinase inhibitor (TKI), has a high potency for controlling BM and reducing the occurrence of brain metastases in advanced HER2-positive BC patients. We hypothesized that SRT or WBRT combined with pyrotinib and capecitabine could decrease intracranial progression in HER2 positive BC with newly diagnosed BM.

MATERIALS/METHODS

In this prospective single-arm phase Ib/II trial (NCT04582968), eligible patients were assigned to either fractionated stereotactic radiotherapy (FSRT) or whole-brain radiation therapy (WBRT), combined with pyrotinib and capecitabine. The primary endpoint was one-year CNS progression-free survival (PFS) rate. Secondary endpoints included intracranial objective response rate (IC-ORR) according to RANO-BM criteria, progression-free survival (PFS), overall survival (OS) and evaluation of safety and neurocognitive function.

RESULTS

From January 2020 to August 2022, 40 patients were enrolled. Twenty-nine patients were treated with FSRT in 8 Gy per fraction with 3 to 5 fractions and 11 were treated with WBRT in 3 Gy per fraction with 10 fractions, and then received chemotherapy in a time frame starting from 0 to 7 days after radiotherapy. At a median follow-up of 17.3 months, 1-year CNS-PFS rate was 74.9% (95% CI 61.9-90.7%) and median CNS-PFS was 18 months (95% CI, 15.5 to NA months). One-year PFS rate was 66.9% (53.1-84.2%) and median PFS time was 17.6 months (95% CI 12.8-34.1 months). The best intracranial response rate (IC-ORR: complete response and partial response) was 92.5% (37/40). The most common grade 3 or worse toxicity was diarrhea (7.5%) and asymptomatic radiation necrosis was detected in 4 of 67(6.0%) lesions treated with FSRT. No differences of neurocognitive function evaluated by MMSE (Mini-Mental State Exam) were observed between different groups at any time point.

CONCLUSION

Radiotherapy combined with pyrotinib and capecitabine resulted in a promising efficacy that crossed the pre-specified boundary in patients with HER2-positive advanced breast cancer with brain metastases. This is the first prospective study showing the efficacy and safety of CNS radiotherapy concurrent with pyrotinib and capecitabine in patients with BM from HER2-positive breast cancer. Further investigation in a randomized controlled study is warranted.

[Clinical and endoscopic characteristics of adult celiac disease]

Objective: The study aimed to analyze the clinical and endoscopic characteristics of adult celiac disease (CD) to provide a scientific basis for more effective CD diagnosis and treatment. Methods: In this cross-sectional study, the clinical and endoscopic data of 96 adult CD patients treated in the Department of Gastroenterology of the People's Hospital of Xinjiang Uygur Autonomous Region from March 2016 to December 2021 were retrospectively collected and analyzed. Results: A total of 96 CD patients were diagnosed, including 33 men and 63 women. The average age was 47±14 years (range, 18-81 years). The disease occurred mainly in the age group of 31-60 years. The median course of the disease was 2.0 (0.2-40.0) years. There were 41 (42.7%) classical and 55 (57.3%) non-classical CD patients. All patients with classical CD showed chronic diarrhea, often accompanied by abdominal pain (46.3%, 19/41), abdominal distension (17.1%, 7/41), anemia (65.9%, 27/41), and chronic fatigue (48.8%, 20/41). The main manifestations of non-classical CD were chronic abdominal pain (58.2%, 32/55), abdominal distension (32.7%, 18/55), anemia (40.0%, 22/55), and osteopenia/osteoporosis (38.2%, 21/55). Compared with non-classical CD, anemia developed more frequently in classical CD, and the difference was statistically significant (P = 0.012). The incidence of complications in CD patients was 36.5% (35/96), and the main complications were thyroid disease (19.8%, 19/96), connective tissue disease (6.2%, 6/96), and kidney disease (6.2%, 6/96). There was no significant difference between classical and non-classical CD (P>0.05). The frequency of endoscopic manifestations in CD patients was 84.4% (81/96). Duodenal bulb endoscopy showed nodular changes (72.9%, 70/96), grooved changes (10.4%, 10/96), and focal villous atrophy (9.4%, 9/96). The main manifestations of descending endoscopy were the decrease, flattening, or disappearance of duodenal folds (43.8%, 42/96), scallop-like changes (38.5%, 37/96), and nodular changes (34.4%, 33/96). Conclusions: Adult CD patients are mostly female. CD occurred mainly in the age group of 31-60 years. The clinical manifestations were mainly those of non-classical CD. Some patients often had other autoimmune diseases. Patients with characteristic endoscopic manifestations should be warned about the possibility of developing CD. Clinicians should strengthen the understanding of CD and reduce the related rates of missed diagnosis.

[Study on the difference of curative effect of conventional mercury displacement treatment on mercury in brain and kidney]

Objective: To explore the expulsion effect of sodium dimercaptopropanesulfonate (DMPS) on mercury in different organs of mercury poisoning and the therapeutic effect of glutathione (GSH) combined with antioxidant therapy on mercury poisoning. Methods: In February 2019, 50 SPF male SD rats were randomly divided into 5 groups, 10 rats in each group: A (saline negative control group) , B (HgCL2 positive control group) , treatment group (C: intramuscular injection of DMPS 15 mg/kg treatment, D: intramuscular injection of DMPS30 mg/kg treatment, E: intramuscular injection of DMPS 15 mg/kg and intraperitoneal injection of GSH200 mg/kg treatment) . Rats in group B, C, D and E were subcutaneously injected with mercury chloride solution (1 mg/kg) to establish a rat model of subacute mercury poisoning kidney injury. Rats in group A were subcutaneously injected with normal saline. After the establishment of the model, rats in the treatment group were injected with DMPS and GSH. Rats in group A and group B were injected with normal saline. At 21 d (treatment 7 d) and 28 d (treatment 14 d) after exposure, urine and blood samples of 5 rats in each group were collected. Blood biochemistry, urine mercury, urine microalbumin and mercury content in renal cortex, cerebral cortex and cerebellum were detected. Results: After exposure to mercury, the contents of mercury in renal cortex, cerebrum and cerebellum of rats in group B, C, D and E increased, and urine microalbumin increased. Pathology showed renal tubular injury and renal interstitial inflammation. Compared with group B, urinary mercury and renal cortex mercury in group C, D and E decreased rapidly after DMPS treatment, and there was no significant decrease in mercury levels in cerebellum and cerebral cortex of rats, accompanied by transient increase in urinary albumin after DMPS treatment (P<0.05) ; the renal interstitial inflammation in group E was improved after GSH treatment. There was a positive correlation between urinary mercury and the contents of mercury in renal cortex, cerebral cortex and cerebellum (r=0.61, 0.47, 0.48, P<0.05) . Conclusion: DMPS mercury expulsion treatment can significantly reduce the level of metal mercury in the kidney, and there is no significant change in the level of metal mercury in the cortex and cerebellum.

Tumor invasion front morphology: a novel prognostic factor for intrahepatic cholangiocarcinoma

OBJECTIVE

To explore the prognostic value of the morphology of tumor invasion front (TIF) in Intrahepatic Cholangiocarcinoma (ICC).

PATIENTS AND METHODS

Seventy-four ICC patients with complete clinicopathological data and follow-up information were enrolled in our study. The most typical morphology of TIF of each case will be classified as low-grade group or high-grade group after evaluation by two pathologists. The clinicopathological characteristics, disease-free survival (DFS), and overall survival (OS) were compared between the two groups.

RESULTS

A total of 26 (35.3%) patients were assigned to low-grade group, while 48 (64.7%) patients were assigned to high-grade group. High-grade group was associated with higher CA19-9 (p=0.032), poor differentiation (p=0.050), larger tumor diameter (p=0.016), advanced T staging (p=0.048), and higher incidence of lymph node (LN) metastasis (0.014). No significant associations were found in demographic and clinical characteristics between the two groups. On multivariable analysis, high-grade group was a significant independent predictor of worse DFS (HR=0.433, 95% CI=0.235-0.800, p=0.002) and OS (HR=0.363, 95% CI=0.187-0.704, p=0.003).

CONCLUSIONS

High-grade morphology of TIF was an independent prognostic factor of ICC.

Combination of Imaging Features and Clinical Biomarkers Predicts Positive Pathology and Microbiology Findings Suggestive of Spondylodiscitis in Patients Undergoing Image-Guided Percutaneous Biopsy

BACKGROUND AND PURPOSE

Pathology and microbiology results for suspected spondylodiscitis on MR imaging are often negative in up to 70% of cases. We aimed to predict whether MR imaging features will add diagnostic value when combined with clinical biomarkers to predict positive findings of spondylodiscitis on pathology and/or microbiology from percutaneous biopsy.

MATERIALS AND METHODS

In this retrospective single-center institutional review board-approved study, patients with radiologically suspected spondylodiscitis and having undergone percutaneous biopsies were assessed. Demographic characteristics, laboratory values, and tissue and blood cultures were collected. Pathology and microbiology results were used as end points. Three independent observers provided MR imaging-based scoring for typical MR imaging features for spondylodiscitis. Multivariate logistic regression and receiver operating characteristic analysis were performed to determine an optimal combination of imaging and clinical biomarkers in predicting positive findings on pathology and/or microbiology from percutaneous biopsy suggestive of spondylodiscitis.

RESULTS

Our patient cohort consisted of 72 patients, of whom 33.3% (24/72) had spondylodiscitis. The mean age was 63 ± 16 years with a male/female ratio of 41:31. Logistic regression revealed a combination with an area under the curve of 0.72 for pathology and 0.68 for pathology and/or microbiology. Epidural enhancement on MR imaging improved predictive performance to 0.87 for pathology and 0.78 for pathology and/or microbiology.

CONCLUSIONS

Our findings demonstrate that epidural enhancement on MR imaging added diagnostic value when combined with clinical biomarkers to help predict which patients undergoing percutaneous biopsy will have positive findings for spondylodiscitis on pathology and/or microbiology.

[Analysis of baseline liver biochemical parameters in 324 cases with novel coronavirus pneumonia in Shanghai area]

Objective: To summarize the clinical characteristics and liver biochemical parameters of 324 cases admitted with novel coronavirus pneumonia in Shanghai area. Methods: Clinical data and baseline liver biochemical parameters of 324 cases with novel coronavirus pneumonia admitted to the Shanghai Public Health Clinical Center from January 20, 2020 to February 24, 2020 were retrospectively analyzed. Patients were divided into two groups based on the status of illness: mild type (mild and typical) and severe type (severe and critical).The differences in clinical data and baseline liver biochemical parameters of the two groups were described and compared. The t-test and Wilcoxon rank-sum test were used for measurement data. The enumeration data were expressed by frequency and rate, and chi-square test was used. Results: Of the 324 cases with novel coronavirus pneumonia, 26 were severe cases (8%), with median onset of 5 days, 20 cases were HBsAg positive (6.2%), and 70 cases (21.6%) with fatty liver, diagnosed with X-ray computed tomography. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), γ-glutamyl transferase (GGT), total bilirubin (TBil), albumin(ALB) and international normalized ratio (INR) of 324 cases at baseline were 27.86 ± 20.02 U/L, 29.33 ± 21.02 U/L, 59.93 ± 18.96 U / L, 39.00 ± 54.44 U/L, 9.46 ± 4.58 μmol / L, 40.64 ± 4.13 g / L and 1.02 ± 0.10. Of which, ALT was > than the upper limit of normal (> ULN), accounting for 15.7% (51/324). ALT and AST > ULN, accounting for 10.5% (34/324). ALP > ULN, accounting for 1.2% (4/324). ALP and GGT > ULN, accounting for 0.9% (3/324). INR > ULN was lowest, accounting for 0.6% (2/324). There were no statistically significant differences (P > 0.05) in ALT [(21.5 vs. 26) U / L, P = 0.093], ALP [(57 vs.59) U/L, P = 0.674], and GGT [(24 vs.28) U/L, P = 0.101] between the severe group and the mild group. There were statistically significant differences in AST (23 U/L vs. 34 U/L, P < 0.01), TBil (10.75 vs. 8.05 μmol / L, P < 0.01), ALB (35.79 ± 4.75 vs. 41.07 ± 3.80 g/L, P < 0.01), and INR (1.00 vs. 1.04, P < 0.01). Conclusion: The baseline liver biochemical parameters of 324 cases with novel coronavirus pneumonia in Shanghai area was comparatively lower and the liverinjury degree was mild, and the bile duct cell damage was rare.

[Clinical characteristics of anomalous origin of the left coronary artery from the pulmonary artery in 91 children]

Objective: To explore the clinical manifestations, diagnosis, treatment and prognosis of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) . Methods: A retrospective study identified 91 patients diagnosed with ALCAPA at Shanghai Children's Medical Center from March 2010 to August 2017. According to the left ventricular ejection fraction (LVEF) at the time of consultation, patients were divided into the cardiac insufficiency group (n=54) and the normal cardiac function group (n=37). Clinical features (age of onset, clinical performance, etc) and auxiliary examinations (electrocardiogram, echocardiography, etc) between the two groups were compared using a t-test and a Chi-square test. Prognostic factors were analyzed by an ordered logistic regression and a Pearson correlation coefficient. Results: (1) The age of diagnosis of patients in the cardiac insufficiency group who were usually misdiagnosed as cardiomyopathy was (10.0±2.6) months (20/54) , whereas the age of diagnosis of patients in the normal cardiac function group who were usually misdiagnosed as valvular diseases was (40.0±7.8) months (4/37). According to the pathophysiological mechanism, forty of the 54 (74%) patients in the cardiac insufficiency group were infantile type, and 78% patients (29/37) in the normal cardiac function group were adult type. (2) Preoperative electrocardiogram showed the deep Q wave in lead I occurred more frequently in the cardiac insufficiency group than in the normal cardiac function group (28/54 vs. 11/37, χ(2)=4.388, P=0.036). (3) Twenty patients died in the cardiac insufficiency group including 12 patients who died from postoperative cardiac pump failure and 8 children who did not undergo surgery due to poor prognosis and died from other reasons. There was no death in the normal cardiac function group. (4) Preoperative LVEF was the unique risk factor affecting prognosis (F=16.872, P=0.005). The preoperative LVEF was significantly lower than the postoperative LVEF ((37±11)% vs. (45±14)%, t=3.614, P=0.001) in the cardiac insufficiency group. During the follow-up period, 6 patients in the cardiac insufficiency group still presented with postoperative cardiac dysfunction, and the patients in the normal cardiac function group still had normal cardiac function. Conclusions: Preoperative LVEF was the unique risk factor affecting prognosis of ALCAPA. Patients with infantile type ALCAPA and preoperative cardiac insufficiency should receive long-term follow-up treatment.

γ-Aminobutyric Acid (GABA) Induced in Vitro Differentiation of Rat Pancreatic Ductal Stem Cells into Insulin-Secreting Islet-Like Cell Clusters

In vitro produced β-like cells can provide promising cell therapy for curing the epidemic of diabetes. In this context, we aimed to investigate the effects of different concentrations of γ-aminobutyric acid (GABA) on the differentiation of rat pancreatic ductal epithelial-like stem cells (PDESCs) into β-like cells. The PDESC line cells were cultured in the basal media (DMEM/F12 + 10% FBS + 1% penicillinstreptomycin) supplemented with 0 μM, 5 μM, 50 μM, 500 μM, and 5 mM of GABA for 28 days to induce their differentiation. The differentiated cells were detected by cell morphology, dithizone (DTZ) staining, immunofluorescence staining, real-time polymerase chain reaction (qPCR), and glucose-stimulated insulin secretion (GSIS) assay to validate their identity. At the end of 28 days, compared with the control group, enrichment of induced cells was high among the 5 μM, 50 μM, 500 μM, and 5 mM GABA induction groups. The formation of islet-like cell clusters (ICCs) began at 14 days, and the cell clusters showed a growth trend with the culture time. The induced ICCs were positive for DTZ staining, while the control group showed negative results for DTZ staining and the differentiated cells were also positive for β-cell-specific markers (Ins1 and Pdx1). GSIS assay of 50 μM induction group cells at 28 days showed significantly higher levels of C-peptide and insulin secretion than the control, 5 μM, 500 μM, and 5 mM GABA-treated groups (P < 0.01). At the same time, the 50 μM induction group cells also showed significantly higher levels of Ins1, Pdx1 and Nkx6.1 mRNA as compared to the 5 μM, 500 μM and 5 mM GABA groups (P < 0.01). Thus, the addition of GABA to the basal medium effectively induced differentiation of adult rat PDESCs into insulin-secreting β-like cells, and 50 μM was the most effective concentration for the induction.

EFFECT OF DORSOMEDIAL HYPOTHALAMUS NEUROPEPTIDE Y KNOCKDOWN ON HEPATIC INSULIN SENSITIVITY

Objective

In this study we investigated the effect of dorsomedial hypothalamus (DMH) neuropeptide Y (NPY) knock-down on hepatic insulin sensitivity in high-fat (HF) diet-fed rats.

Methods

Forty-eight Sprague-Dawley rats were randomly assigned to receive bilateral DMH injections of adeno-associated virus AAVshNPY or AAVshCTL and then accessed to regular chow. Five weeks after viral injection, half rats in each group were given access to the HF diet. At 16 weeks, rat livers were collected. Insulin receptor substrate-1 (IRS-1) and phosphoinositide 3-kinase (PI3K) mRNA expression was measured by qRT-PCR. Blood glucose levels were measured by the oxidase method, serum insulin, triglyceride, and TC levels were measured by Elisa. Pathological changes in the liver were assessed by hematoxylin-eosin (HE) staining. AKT, p-AKT, and GSK-3 levels were measured by western blotting.

Results

Compared with AAVshCTL-injected rats, AAVshNPY-injected rats showed a significant decrease in blood glucose concentrations; serum insulin, triglyceride, and TC; HOMA-IR; and IRS-1 and PI3K mRNA levels (P<0.05). ISI, GSK-3, and p-AKT levels were significantly increased (P<0.05). HE staining showed that AAVshNPY-injected rats fed the HF diet had mild fatty degeneration.

Conclusion

These results suggest that DMH NPY knock-down improves hepatic insulin sensitivity in HF diet-fed rats by activating the hepatic PI3K/AKT insulin signalling pathway.

Probiotic Bacillus enhance the intestinal epithelial cell barrier and immune function of piglets

Bacillus is widely used in the livestock industry. This study was designed to evaluate the effects of probiotic Bacillus amyloliquefaciens SC06 (Ba), originally isolated from soil, in piglets diet as an alternative to antibiotics (aureomycin), mainly on intestinal epithelial barrier and immune function. Ninety piglets were divided into three groups: G1 (containing 150 mg/kg aureomycin in the diet); G2 (containing 75 mg/kg aureomycin and 1×108 cfu/kg Ba in the diet); G3 (containing 2×108 cfu/kg Ba in the diet without any antibiotics). The results showed that, compared with the antibiotic group (G1), villus length, crypt depth and villus length/crypt depth ratio of intestine significantly increased in the G2 and G3 groups. In addition, intestinal villi morphology, goblet-cell number, mitochondria structure and tight junction proteins of intestinal epithelial cells in G2 and G3 were better than in G1. The relative gene expression of intestinal mucosal defensin-1, claudin3, claudin4, and human mucin-1 in G3 was significantly lower, while the expression of villin was significantly higher than in the antibiotic group. Probiotic Ba could significantly decrease serum interferon (IFN)-α, IFN-γ, interleukin (IL)-1β, and IL-4 levels, whereas increase tumour necrosis factor (TNF)-α and IL-6 secretion. Ba could also significantly decrease cytokines TNF-α, IFN-γ, IL-1β, and IL-4 level in liver, whereas it significantly increased IFN-α. Furthermore, replacing antibiotics with Ba also significantly down-regulated gene expression of TNF and IL-1α in intestinal mucosa, but up-regulated IL-6 and IL-8 transcription. Dietary addition of Ba could significantly reduce the gene expression of nuclear factor kappa beta (NFκB)-p50 and Toll-like receptor (TLR)6, while there was no significant difference for that of myeloid differentiation primary response 88, TNF receptor-associated factor-6, nucleotide-binding oligomerisation domain-containing protein 1, TLR2, TLR4, and TLR9. Taken together, our findings demonstrated that probiotic Ba could increase the intestinal epithelial cell barrier and immune function by improving intestinal mucosa structure, tight junctions and by activating the TLRs signalling pathway.

[The impact of genetic variation of KDR on clinical outcomes of advanced colorectal cancer patients treated by first line bevacizumab based regimens]

Objective: To investigate the association between kinase insertion region receptor (KDR) gene genetic variation and the efficacy of bevacizumab in patients with advanced colorectal cancer(CRC) were investigated in this study. Methods: 118 patients with advanced colorectal cancer who were treated by bevacizumab based first line regimens were included in this study. Peripheral blood and the biopsy tissue specimens of the CRC patients were collected for the genotyping of genetic variation and KDR gene expression, respectively. The univariate analysis of genotypes and prognosis was carried out by Kaplan-Meier survival analysis, and multivariate were adjusted by Cox regression analysis. Results: Located in the coding region, the prevalence of 889 C>T in KDR among the study population were as follows: CC genotype 86 cases (72.88%), CT genotype 30 cases (25.42%), TT genotype 2 cases (1.70%), minor allele frequency of 889 C>T is 0.14. The distribution of three genotypes in accordance with Hardy-Weinberg Equilibrium (P=0.737). There were no statistical differences in the distribution of the genotypes in baseline clinical data. TT and CT genotype patients were merged in the comparison of clinical outcomes. The clinical outcomes analysis of patients with different genotypes found that the objective response rates (ORR) of CT/TT genotypes were 34.38% and 43.02% (P=0.395), respectively. And the median progression free survival (PFS) of patients with CT/TT genotype and CC genotype were 7.5 and 9.7 months respectively, which was statistically significant (P=0.009). In terms of overall survival (OS), the median OS of the two genotypes were 19.3 and 20.1 (P=0.025), respectively. Adjusted in multivariate Cox regression analysis of PFS, CT/TT genotypes were an independent factor for PFS (OR=1.88, P=0.023). Additionally, of the 57 biopsy tissue specimens, gene expression analysis was conducted. And the results showed that the expression of KDR in cancer tissues of the patients with CT/TT genotypes were significantly higher than those of the CC genotype patients (P<0.001). Conclusion: Among advanced colorectal cancer patients treated by bevacizumab, the polymorphism 889 C>T of KDR may impact the clinical outcomes of bevacizumab first line treatment by influencing the mRNA expression of KDR.

Microfluidic co-culture platform for investigating osteocyte-osteoclast signalling during fluid shear stress mechanostimulation

Bone cells exist in a complex environment where they are constantly exposed to numerous dynamic biochemical and mechanical stimuli. These stimuli regulate bone cells that are involved in various bone disorders, such as osteoporosis. Knowledge of how these stimuli affect bone cells have been utilised to develop various treatments, such as pharmaceuticals, hormone therapy, and exercise. To investigate the role that bone loading has on these disorders in vitro, bone cell mechanotransduction studies are typically performed using parallel plate flow chambers (PPFC). However, these chambers do not allow for dynamic cellular interactions among different cell populations to be investigated. We present a microfluidic approach that exposes different cell populations, which are located at physiologically relevant distances within adjacent channels, to different levels of fluid shear stress, and promotes cell-cell communication between the different channels. We employed this microfluidic system to assess mechanically regulated osteocyte-osteoclast communication. Osteoclast precursors (RAW264.7 cells) responded to cytokine gradients (e.g., RANKL, OPG, PGE-2) developed by both mechanically stimulated (fOCY) and unstimulated (nOCY) osteocyte-like MLO-Y4 cells simultaneously. Specifically, we observed increased osteoclast precursor cell densities and osteoclast differentiation towards nOCY. We also used this system to show an increased mechanoresponse of osteocytes when in co-culture with osteoclasts. We envision broad applicability of the presented approach for microfluidic perfusion co-culture of multiple cell types in the presence of fluid flow stimulation, and as a tool to investigate osteocyte mechanotransduction, as well as bone metastasis extravasation. This system could also be applied to any multi-cell population cross-talk studies that are typically performed using PPFCs (e.g. endothelial cells, smooth muscle cells, and fibroblasts).

Dynamic changes of global DNA methylation and hypermethylation of cell adhesion-related genes in rat kidneys in response to ochratoxin A

Ochratoxin A (OTA), which is found in a variety of food products, is associated with the development of nephrotoxicity and carcinogenicity in rats and has raised public health concerns. A previous study in our laboratory indicated that OTA exposure induced cytotoxicity by decreasing global DNA methylation in vitro. However, the relationship between OTA-induced nephrotoxicity and DNA methylation changes in vivo remains unclear. The object of this study was to investigate whether OTA can change global DNA methylation or alter the expression of several critical tumour-related genes by inducing methylation modifications before carcinogenesis. We focused on the mechanism of action of OTA in regard to DNA methylation, including the expression of DNA methyltransferases and the regulation of specific cell signalling pathways. Dynamic and dose-dependent changes of global DNA methylation were observed during OTA-induced nephrotoxicity and probably associated with the expression of DNA methyltransferase 1. 13-week exposure of OTA caused hypermethylation in the promoters of critical cell adhesion-related genes, E-cadherin and N-cadherin, leading to reduction of the corresponding mRNA expression, accompanied by transcriptional activation of the Wnt and PI3K/AKT pathways. These findings suggested that long-term OTA exposure could disrupt DNA methylation profile, which might be one of the possible mechanisms of OTA-induced nephrotoxicity.

17β-oestradiol enhances global DNA hypomethylation in CD4-positive T cells from female patients with lupus, through overexpression of oestrogen receptor-α-mediated downregulation of DNMT1

BACKGROUND

Systemic lupus erythematosus (SLE) affects primarily women, and oestrogen appears to play a significant role in SLE development. Our previous studies showed that inhibition of DNA methyltransferase 1 (DNMT1) enhanced global DNA hypomethylation in CD4+ T cells isolated from patients with SLE, and exacerbated SLE. However, the effects of 17β-oestradiol on global DNA hypomethylation and DNMT1 expression in CD4+ T cells of female patients with SLE remain largely unknown.

AIM

To investigate the ability of 17β-oestradiol to affect global DNA methylation in female SLE CD4+ T cells and the mechanism(s) underlying this ability.

METHODS

We enrolled 30 women with SLE and 15 controls. CD4+ T cells exposed to 17β-oestradiol were analysed by global DNA methylation measurements, western blotting and real-time PCR. Plasma 17β-oestradiol levels were measured by ELISA.

RESULTS

In female SLE CD4+ T cells, 17β-oestradiol downregulated DNMT1 expression at both the mRNA and protein levels, and enhanced global DNA hypomethylation. Plasma 17β-oestradiol levels were similar in patients with SLE and controls. The mRNA expression of oestrogen receptor (ER)α, but not of ERβ, was upregulated in SLE CD4+ T cells. Furthermore, the 17β-oestradiol-induced downregulation of DNMT1 expression and global DNA hypomethylation were rescued by an ER antagonist.

CONCLUSIONS

17β-oestradiol enhances global DNA hypomethylation in female SLE CD4+ T cells via downregulation of DNMT1 mediated by ERα overexpression.

The protective effect of telmisartan in Type 2 diabetes rat kidneys is related to the downregulation of thioredoxin-interacting protein

BACKGROUND

Thioredoxin-interacting protein (Txnip), an inhibitor of thioredoxin (Trx), increases in diabetic nephropathy and promotes oxidative stress. The angiotensin II (Ang II) receptor blocker telmisartan may protect renal function in diabetic models and patients via multiple effects including antioxidation. However, its mechanism has not been fully elucidated, and its relationship to Txnip remains unclear.

AIM

This study aimed to investigate whether telmisartan ameliorates oxidative stress by regulating Txnip and Trx expression in Type 2 diabetic rat kidneys and explore the possible relationship between renoprotection by telmisartan and Txnip.

METHODS

Twenty-one rats were equally divided into control (C), streptozotocin-induced diabetic (D), and telmisartan- treated diabetic (T) groups. Txnip and Trx expression in rat kidneys was analyzed by immunohistochemistry, RTPCR, and western blot. Peroxisome proliferator-activated receptor- γ (PPARγ), NADPH oxidase activity, and parameters of renal function and oxidative stress were also measured.

RESULTS

Trx and PPARγ were significantly decreased, and Txnip expression and NADPH oxidase activity markedly increased, in the D and T groups compared to the C group. After telmisartan treatment, Trx and PPARγ were upregulated, while Txnip expression and NADPH oxidase activity were downregulated. Parameters of renal function and oxidative stress were improved by telmisartan.

CONCLUSION

Telmisartan ameliorates oxidative stress and protects renal function in Type 2 diabetic rat kidneys. The downregulation of Txnip by telmisartan may be associated with PPARγ activation.