[Regulatory relationship between lncRNA KCNQ1OT1 and miR-146a-3p in preeclampsia].

Objective: To observe the changes of the expression level of long non-coding RNA (lncRNA) KCNQ1OT1 and microRNA (miR)-146a-3p in placenta tissues of preeclampsia (PE) patients, as well as their effect and mechanism on the biological functions of trophoblast cells. Methods: A total of 45 cases of hospitalized PE patients in Hainan General Hospital from July 2017 to July 2018 were selected as the PE group, 55 normal pregnant women during the same period were chosed as the control group. The expression level of KCNQ1OT1 mRNA and miR-146a-3p in the placenta tissues between two groups were detected by using quantitative real time (qRT)-PCR. Pearson's test was furtherly analyzed the correlation between them. Human trophoblast cell line (HTR8/SVneo) were randomly divided into control and lipopolysaccharide (LPS) groups, and then LPS group were divide into four sub-groups,included LPS group, short hairpin RNA (sh)-KCNQ1OT1 (after silencing the expression of KCNQ1OT1), miR-146a-3p inhibitor and sh-KCNQ1OT1+miR-146a-3p inhibitor. The targeting relationship between KCNQ1OT1 and miR-146a-3p were predicted by bioinformatics software and confirmed by luciferase assay. The cell proliferation and invasion capacities were respectively detected by cell counting kit-8 (CCK-8) and transwell assay. The expression level of KCNQ1OT1 mRNA and miR-146a-3p were detected by qRT-PCR and the protein expression level of CXC chemokine ligand 12 （CXCL12） and CXC chemokine receptor type 4 (CXCR4) were tested by western blot. Results: (1) The mRNA expression level of KCNQ1OT1 in the placenta of PE group was lower than that of control group (0.23±0.03 vs 0.51±0.04, P<0.05), and the miR-146a-3p expression level was higher than that of the control group (0.49±0.03 vs 0.31±0.03, P<0.05), there were statistical significant differences between the two groups. (2) Luciferase assay showed that there was a targeting relationship between KCNQ1OT1 and mir-146a-3p. Compared with the control group, the mRNA expression level of KCNQ1OT1 in the LPS group were significantly decreased (0.91±0.03 vs 0.35±0.03, P<0.05), and the expression level of miR-146a-3p were significantly increased (0.22±0.03 vs 0.63±0.04, P<0.05). The cell proliferation, invasion and migration capacities and the protein expression of CXCL12 and CXCR4 significantly reduced in the LPS group compared with control group (all P<0.05). The mRNA expression level of KCNQ1OT1 (0.23±0.03) in the sh-KCNQ1OT1 group were further decreased, the expression of miR-146a-3p (0.85±0.03) were further increased, and the cell proliferation, invasion and migration capacities and the protein expression of CXCL12 and CXCR4 were all further reduced compared with control group，there were significant difference between two groups (all P<0.05). Comparing the miR-146a-3p inhibitor group, and sh-KCNQ1OT1+miR-146a-3p inhibitor group with the sh-KCNQ1OT1 group, respectively, the expression level of KCNQ1OT1 mRNA (0.78±0.04 vs 0.50±0.03) increased, and the expression level of miR-146a-3p (0.42±0.03 vs 0.46±0.03) decreased, the cell proliferation, invasion and migration capacities and the protein expression of CXCL12 and CXCR4 were all increased ,there were statistically significant differences (all P<0.05). Conclusion: KCNQ1OT1 could target the regulation of miR-146a-3p through CXCL12/CXCR4 pathway in the proliferation, invasion an migration of HTR8/SVneo cells, which may be involved in the pathogenesis of PE.

Patients With Long-QT Syndrome Caused by Impaired hERG-Encoded Kv11.1 Potassium Channel Have Exaggerated Endocrine Pancreatic and Incretin Function Associated With Reactive Hypoglycemia.

BACKGROUND: Loss-of-function mutations in hERG (encoding the Kv11.1 voltage-gated potassium channel) cause long-QT syndrome type 2 (LQT2) because of prolonged cardiac repolarization. However, Kv11.1 is also present in pancreatic α and ß cells and intestinal L and K cells, secreting glucagon, insulin, and the incretins glucagon-like peptide-1 (GLP-1) and GIP (glucose-dependent insulinotropic polypeptide), respectively. These hormones are crucial for glucose regulation, and long-QT syndrome may cause disturbed glucose regulation. We measured secretion of these hormones and cardiac repolarization in response to glucose ingestion in LQT2 patients with functional mutations in hERG and matched healthy participants, testing the hypothesis that LQT2 patients have increased incretin and ß-cell function and decreased α-cell function, and thus lower glucose levels. METHODS: Eleven patients with LQT2 and 22 sex-, age-, and body mass index-matched control participants underwent a 6-hour 75-g oral glucose tolerance test with ECG recording and blood sampling for measurements of glucose, insulin, C-peptide, glucagon, GLP-1, and GIP. RESULTS: In comparison with matched control participants, LQT2 patients had 56% to 78% increased serum insulin, serum C-peptide, plasma GLP-1, and plasma GIP responses (P=0.03-0.001) and decreased plasma glucose levels after glucose ingestion (P=0.02) with more symptoms of hypoglycemia (P=0.04). Sixty-three percent of LQT2 patients developed hypoglycemic plasma glucose levels (<70 mg/dL) versus 36% control participants (P=0.16), and 18% patients developed serious hypoglycemia (<50 mg/dL) versus none of the controls. LQT2 patients had defective glucagon responses to low glucose, P=0.008. ß-Cell function (Insulin Secretion Sensitivity Index-2) was 2-fold higher in LQT2 patients than in controls (4398 [95% confidence interval, 2259-8562] versus 2156 [1961-3201], P=0.03). Pharmacological Kv11.1 blockade (dofetilide) in rats had similar effect, and small interfering RNA inhibition of hERG in ß and L cells increased insulin and GLP-1 secretion up to 50%. Glucose ingestion caused cardiac repolarization disturbances with increased QTc intervals in both patients and controls, but with a 122% greater increase in QTcF interval in LQT2 patients (P=0.004). CONCLUSIONS: Besides a prolonged cardiac repolarization phase, LQT2 patients display increased GLP-1, GIP, and insulin secretion and defective glucagon secretion, causing decreased plasma glucose and thus increased risk of hypoglycemia. Furthermore, glucose ingestion increased QT interval and aggravated the cardiac repolarization disturbances in LQT2 patients. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT02775513.

Anti-Voltage-gated Potassium Channel Limbic Encephalitis with Psychiatric Features: a Case Report.

We report a case of anti-voltage-gated potassium channel (VGKC) limbic encephalitis in a 47-year-old man presenting with a 2-year history of psychiatric features. The patient had cognitive impairment, slurred speech, and a mildly unsteady gait but no other neurological deficits or seizures. Results of blood, urine, and cerebrospinal fluid tests and magnetic resonance imaging of the brain were normal. However, electroencephalography showed an epileptogenic focus in the bilateral temporal regions with mild to moderate diffuse encephalopathy. Autoimmune panel results confirmed the diagnosis of anti-VGKC limbic encephalitis, with a serum VGKC concentration of 6730 pmol/L. The patient was treated with Keppra and pulsed intravenous methylprednisolone for 3 days, and his behaviour improved.