Downregulation of DNMT3a expression by RNAi and its effect on NF-κBs expression of thymic epithelial cells

OBJECTIVE

To understand the characteristics of DNA methyltransferase 3a (DNMT3a) in thymoma associated Myasthenia Gravis reveal its transcriptional regulator network as while as analyze the effect of DNMT3a on Rel/ nuclear factor-kappaB family (RelA/RelB) and its downstream autoimmune regulatory factor (Aire).

METHODS

Tissues of 30 patients with thymoma, with or without myasthenia gravis (MG), were collected and the DNMT3a protein expression were evaluated through immunohistochemistry. We performed mRNA expression profiling microarray detection and analysis, and integrated the analysis by constructing protein-protein interaction networks and the integration with other database. We identified molecular difference between low and high DNMT3a in the thymoma by heatmap. We also performed PCR validation in thymoma tissues. The DNMT3a-shRNA plasmid was transfected into TEC cells, and these cells were treated with 5-aza-2-deoxycytidine, a blocker of DNMT3a. After the down-regulation of DNMT3a in TEC cells, the transcript and protein levels of RelA, RelB, Aire, and CHRNA3 were evaluated by western blotting. In addition, changes in gene expression profiles were screened through microarray technology. We performed differential gene analysis in the thymoma cohort by heatmap with R (v.4.3.0) software.

RESULTS

In 30 matched tissue specimens, the expression of DNMT3a protein in thymoma with MG was lower than that in thymoma. Through mRNA expression profiling analysis, we constructed a co-expression network of DNMT3a and found direct interaction between IKZF1 and DNMT3a, and this co-expression relationship was overlappted with Cistrome DB database. We found up-regulation of 149 mRNAs and repression of 177 mRNAs in thymoma with MG compared with thymoma. Gene ontology and pathway analysis show the involvement of a multitude of genes in the mis-regulation of MG-related pathways. RNA interference significantly reduced the level of mRNA of DNMT3a, which proved that plasmid DNMT3a was effective. In comparison to the control group, the levels of DNMT3a, Aire, and CHRNA3 mRNA and protein in TEC cells transfected with DNMT3a-shRNA interference plasmid were significantly decreased, while the expression level of RelA and RelA/RelB was significantly increased.

CONCLUSIONS

Our study reveals the DNMT3a-NF-κB pathway has a major effect on MG, and can be used as a marker for diagnosis as well as a target for MG treatment.

Prognostic factors and survival outcome of primary pulmonary acinar cell carcinoma

Purpose

The objective of our study was to investigate the epidemiologic characteristics and prognostic factors in patients with pulmonary acinar cell carcinoma (PACC).

Methods

PACC patients diagnosed between 1975 and 2016 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The trend in PACC incidence was assessed using joinpoint regression software. Overall survival (OS) and disease‐specific survival (DSS) were evaluated using the Kaplan–Meier method and log‐rank test. Univariate and multivariate Cox regression analysis was performed to identify the independent prognostic factors for OS and DSS. Nomograms to predict survival possibilities were constructed based on the identified independent prognostic factors.

Results

A total of 2918 patients were identified with PACC. The mean age was 65.2 ± 8.95 years with a female to male of 1.6:1. The incidence of PACC steadily increased by an annual percentage change (APC) of 3.2% (95% CI 2.1–4.4, p < 0.05). Multivariate Cox regression analysis revealed that age, gender, race, stage, grade, tumor size, number of positive lymph nodes, surgery, and chemotherapy were independent prognostic factors for survival. Nomograms specifically for PACC were constructed to predict 1‐ and 5‐year OS and DSS possibility, respectively. The concordance index (C‐index) and calibration plots showed the established nomograms had robust and accurate performance.

Conclusion

PACC was rare but the incidence has been steadily increasing over the past four decades. Survival has improved in recent years. Surgery or chemotherapy could provide better OS and DSS. The established nomograms specifically for PACC were robust and accurate in predicting 1‐ and 5‐year OS and DSS.

[Perioperative stroke effectively treated by an acute stroke team including anesthesia department: a case report]

Perioperative stroke is cerebral infarction occurring in the perioperative period. The incidence of perioperative stroke in non-cardiac, and non-neurologic surgery is about 0.7%, but the mortality can be as high as 26% to 40%. The outcome of the patients with perioperative stroke can be disastrous. Here we report a case of perioperative ischemic stroke that occurred after surgery of lumbar decompression and pedical screw fixation. A 76-year-old female admitted to our hospital because of lumbar spinal stenosis. Her medical history included hypertension and diabetes for ten years. Her personal history included a smoking history of 60 years by 2 cigarettes per day, not quitting. Her carotid artery ultrasound showed multiple low echo plaques on the right side and multiple high echo plaques on the left side of the carotid artery, but without distinct stenosis. Other examinations and tests showed no distinct abnormality. She went on a lumbar decompression and pedical screw fixation uneventfully. The blood loss was 400 mL and autologous blood transfusion 150 mL. The arterial blood pressure (ABP) maintained during 100-130 mmHg/60-80 mmHg (1 mmHg=0.133 kPa). Sixty minutes after she recovered from general anesthesia, the patient developed symptoms of slurred speech and right limbs weakness. The anesthesio-logist evaluated the patient immediately with National Institute of Health Stroke Scale (NIHSS). The NIHSS score was 11 and a stroke was highly suspected. The acute stroke team was therefore initiated and fast responded. Within 4 h, digital subtraction angiography (DSA) was proceeded, which showed the M1 segment of the left middle cerebral artery was occluded and the local stenosis of her right middle cerebral artery was up to 80%. After the successful embolectomy by Solitaire stent, the left middle cerebral artery reflowed and the forward blood flow was thrombolysis in myocardial infarction (TIMI) grade 3. The patient was discharged after 33 days after the surgery with a NIHSS of 9. Our case provides an example that an acute stroke team that included the department of anesthesiology can be beneficial to the patients' perioperative strokes. During the perioperative period, anesthesiologists should be included into the acute stroke team, because anesthesiologists and anesthesia nurses might be first observers of those early onset strokes. Our case also put forward this thought that a standard peri-operative stroke evaluation tool, like NIHSS, should be discussed and applied to facilitate and accelerate the initiation of perioperative acute stroke team.

SIRT1 mediates salidroside-elicited protective effects against MPP+ -induced apoptosis and oxidative stress in SH-SY5Y cells: involvement in suppressing MAPK pathways

Parkinson's disease (PD) is a progressive neurodegenerative disease, leading to tremor, rigidity, bradykinesia, and gait impairment. Salidroside has been reported to exhibit antioxidative and neuroprotective properties in PD. However, the underlying neuroprotective mechanisms effects of salidroside are poorly understood. Recently, a growing body of evidences suggest that silent information regulator 1 (SIRT1) plays important roles in the pathophysiology of PD. Hence, the present study investigated the roles of SIRT1 in neuroprotective effect of salidroside against N-methyl-4-phenylpyridinium (MPP⁺ )-induced SH-SY5Y cell injury. Our findings revealed that salidroside attenuates MPP⁺ -induced neurotoxicity as evidenced by the increase in cell viability, and the decreases in the caspase-3 activity and apoptosis ratio. Simultaneously, salidroside pretreatment remarkably increased SIRT1 activity, SIRT1 mRNA and protein levels in MPP⁺ -treated SH-SY5Y cell. However, sirtinol, a SIRT1 activation inhibitor, significantly blocked the inhibitory effects of salidroside on MPP⁺ -induced cytotoxicity and apoptosis. In addition, salidroside abolished MPP⁺ -induced the production of reactive oxygen species (ROS), the up-regulation of NADPH oxidase 2 (NOX2) expression, the down-regulations of superoxide dismutase (SOD) activity and glutathione (GSH) level in SH-SY5Y cells, while these effects were also blocked by sirtinol. Finally, we found that the inhibition of salidroside on MPP⁺ -induced phosphorylation of p38, extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) were also reversed by sirtinol in SH-SY5Y cells. Taken together, these results indicated that SIRT1 contributes to the neuroprotection of salidroside against MPP⁺ -induced apoptosis and oxidative stress, in part through suppressing of mitogen-activated protein kinase (MAPK) pathways.

Bacterially expressed double-stranded RNAs against hot-spot sequences of tobacco mosaic virus or potato virus Y genome have different ability to protect tobacco from viral infection

Posttranscriptional gene silencing, also known as RNA interference, involves degradation of homologous mRNA sequences in organisms. In plants, posttranscriptional gene silencing is part of a defense mechanism against virus infection, and double-stranded RNA is the pivotal factor that induces gene silencing. In this paper, we got seven hairpin RNAs (hpRNAs) constructs against different hot-spot sequences of Tobacco mosaic virus (TMV) or Potato virus Y (PVY) genome. After expression in Escherichia coli HT115, we extracted the seven hpRNAs for the test in tobacco against TMV or PVY infection. The data suggest that different hpRNAs against different hot-spot sequences of TMV or PVY genome had different ability to protect tobacco plants from viral infection. The resistance to TMV conferred by the hpRNA against the TMV movement protein was stronger than other TMV hpRNAs; the resistance to PVY conferred by the hpRNA against the PVY nuclear inclusion b was better than that induced by any other PVY hpRNAs. Northern blotting of siRNA showed that the resistance was indeed an RNA-mediated virus resistance.