the mechanism of lncrna neat1 in alleviating acute respiratory distress syndrome through mir-27b regulated nrf2 pathway

Conditions: Acute Respiratory Distress Syndrome; Inflammation

Summary: the acute respiratory distress syndrome, formerly known as the acute lung injury (ards/ali), is a critical illness with high mortality due to the lack of effective treatment. the pathogenesis of ards/ali has not been fully elucidated. nuclear factor e2-related factor 2 (nrf2) plays a key role in regulating lung inflammation and oxidative stress which are closely related to lung injury in ards/ali, but its regulatory mechanism remains unclear. the investigator's provious study shown that microrna-27b (mir-27b) downregulated nrf2 to aggravate lung inflammation and histological injury. furthermore, in lipopolysaccharide (lps)-induced cell (j774a.1) inflammation model, mir-27b was upregulated while the long non-coding rna (lncrna) neat1 was downregulated, the putative binding sites of lncrna neat1 and mir-27b were successfully predicted by bioinformatics approach. thus, the investigators propose that neat1 plays as a competing endogenous rna (cerna) to adsorb mir-27b and liberate nrf2, therefore, to attenuate lung inflammation and related lung injury in ards/ali. this project aims to explore the role of the lncrna neat1/ mir-27b /nrf2 signal axis in the development and treatment of ards/ali in patients, as well as in lps-induced ali animal and cell models by using bioinformatics, molecular biology, histomorphology and clinical phenotype approaches, and to clarify the new mechanism in ards/ali development and to provide new therapeutic targets.

collect blood and balf from 400 ards patients at different time (at check-in, 24, 48 and 72 h after check-in the hospital) and 25 gender and age matching healthy controls. use rt-pcr to detect the expression of lncrna neat1、mir-27b and nrf2 in blood and balf of ards patients and health controls. the expressions of inflammatory and oxidative stress associated factors (nlrp3、nf-κb-p65、 p-p65、iκb、p-iκb、ho-1、nqo1、caspase-1、il-1β、il-6、il-18、tnf-α) will be detected by western blot、elisa and rt-pcr. moreover, flow cytometry will be adopted to measure the numbers and kinds of cells in balf. then, analyze the differences of the expressions of lncrna neat1、mir-27b and nrf2 in the groups. to explore the correlation of expressions of lncrna neat1、mir-27b and nrf2 with inflammation and oxidative stress in the groups. finally, to declare the relative of lncrna neat1、mir-27b and nrf2 with the time of mechanical ventilation, severity and mortality in 28 days of ards patients.

Eligibility criteria:
inclusion criteria: we included patients with acute respiratory distress according to 2012 ards berlin new definition (acute respiratory distress syndrome: the berlin definition. jama, 2012, 307(23):2526). * acute or progressive dyspnea within 1 week with identify cause; * chest radiograph/chest ct showed double lung infiltration, which could not be fully explained by pleural effusion, atelectasis, or nodules; * respiratory failure cannot be fully explained by heart failure and fluid overload; * hypoxemia, partial pressure of oxygen in arterial blood (pao2)/oxygen fraction in air (fio2) \<150 mm hg under peep ≥5 cm h2o, (mild ards: 200mmhg\<pao2/fio2≤300mmhg, moderate ards: 100mmhg\<pao2/fio2≤200mmhg, severe ards: pao2/fio2≤100mmhg); * 18\~70 years old; * agree to participate in the trial, and sign the informed consent. exclusion criteria: * age less than 18 years old; * time of hospital stay \<24 h; * pregnancy; * using v-v ecom; * cardiac index \<1.5l·ml.min-1.m-2; * pulmonary resection; * pulmonary embolism ; * refused to participate in the study.

Keywords: long non-coding rna neat1 microrna-27b nuclear factor e2-related factor 2