The Activation of AMPK/NRF2 Pathway in Lung Epithelial Cells Is Involved in the Protective Effects of Kinsenoside on Lipopolysaccharide-Induced Acute Lung Injury.

The disorder of mitochondrial dynamic equilibrium of lung epithelial cell is one of the critical causes of acute lung injury (ALI). Kinsenoside (Kin) serves as an active small-molecule component derived from traditional medicinal herb displaying multiple pharmacological actions in cancers, hyperglycemia, and liver disease. The objective of this study was to investigate the effects of Kin on lipopolysaccharide- (LPS-) induced ALI and further explore possible molecular mechanisms. Kin was administered orally (100 mg/kg/day) for 7 consecutive days before LPS instillation (5 mg/kg). After 12 hours, pathological injury, inflammatory response, and oxidative stress were detected. The results demonstrated that Kin significantly alleviated lung pathological injury and decreased the infiltration of inflammatory cells and the release of inflammatory mediators in bronchoalveolar lavage fluid (BALF), apart from inhibiting the production of reactive oxygen species (ROS) and lipid peroxidation. Meanwhile, Kin also promoted mitochondrial fusion and restrained mitochondrial fission in mice with ALI. In terms of mechanism, Kin pretreatment increased the phosphorylation of AMP-activated protein kinase (AMPK) and the protein level of nuclear factor erythroid 2-related factor 2 (NRF2). In Ampk-α knockout mice challenged with LPS, Kin lost its pulmonary protective effects, accompanied by lower NRF2 level. In vitro experiments further unveiled that either AMPK inhibition by Compound C or NRF2 knockdown by siRNA abolished the protective roles of Kin in LPS-treated A549 lung epithelial cells. And NRF2 activator TAT-14 could reverse the effects of Ampk-α deficiency. In conclusion, Kin possesses the ability to prevent LPS-induced ALI by modulating mitochondrial dynamic equilibrium in lung epithelial cell in an AMPK/NRF2-dependent manner.

[A comparative study on clinical effects of dexmedetomidine and midazolam on patients with severe coronavirus disease 2019 on non-invasive ventilation].

OBJECTIVE: To compare the therapeutic effects and safety of dexmedetomidine and midazolam on patients with severe coronavirus disease 2019 (COVID-19) who received non-invasive ventilation. METHODS: Patients with COVID-19 who needed non-invasive ventilation in one critical care medicine ward of Wuhan Jinyintan Hospital during the team support period from the department of critical care medicine of Renmin Hospital of Wuhan University from January 23rd to February 15th in 2020 were investigated retrospectively. Ramsay score, mean arterial pressure (MAP), heart rate (HR), respiratory rate (RR), arterial oxygen partial pressure (PaO2) before sedation and at 1, 12, 24 hours after sedation, sleep time were collected, and the side effects such as excessive sedation, fall of tongue, abdominal distension, aspiration, bradycardia, escalation to invasive mechanical ventilation during 24 hours were also collected. According to different sedative drugs, patients were divided into the control group (without sedative drugs), dexmedetomidine group and midazolam group. The changes of indicators among the three groups were compared. RESULTS: Fourteen patients were injected with dexmedetomidine (loading dose of 1 µg/kg for 10 minutes, maintained at 0.2-0.7 µg×kg-1×h-1); 9 patients were injected with midazolam (loading dose of 0.05 mg/kg for 2 minutes, maintained at 0.02-0.10 mg×kg-1×h-1); 12 patients didn't use sedative drugs due to limitations of previous hospital or patients' rejection. In dexmedetomidine group and midazolam group, the Ramsay score was maintained at 2-3 points after sedation, which were higher than those of control group at different time points after sedation, and there was no significant difference between dexmedetomidine group and midazolam group. MAP of dexmedetomidine group and midazolam group decreased gradually after sedation. MAP after 1-hour sedation was significantly lower than that before sedation, and MAP after 24 hours sedation was significantly lower than that in the control group [mmHg (1 mmHg = 0.133 kPa): 109.7±11.5, 107.1±12.3 vs. 121.1±13.3, both P < 0.05]. HR decreased gradually after sedation treatment, which was significantly lower after 12 hours of sedation than that before sedation, and HR in dexmedetomidine group was significantly lower than that in control group after 12 hours of sedation (bpm: 84.0±13.9 vs. 92.8±15.4 at 12 hours; 81.0±16.7 vs 92.6±12.7 at 24 hours, both P < 0.05). PaO2 increased and RR decreased in all three groups after ventilation. PaO2 in dexmedetomidine group and midazolam group were significantly higher than that in the control group after 12 hours of sedation [cmH2O (1 cmH2O = 0.098 kPa): 79.0±6.5, 79.0±8.9 vs. 70.0±7.8, both P < 0.05]; the decreases of RR in dexmedetomidine group and midazolam group were significant than that in control group after 1 hour of sedation (bpm: 34.0±3.9, 33.8±4.6 vs. 39.0±3.6, both P < 0.05). There were no differences of MAP, HR, PaO2 and RR between dexmedetomidine group and midazolam group at different time points. The sleep duration in dexmedetomidine group and midazolam group were significantly longer than that in the control group (hours: 4.9±1.9, 5.8±2.4 vs. 3.0±1.8, both P < 0.05), but there was no difference between dexmedetomidine group and midazolam group (P > 0.05). Adverse events occurred in all three groups. In midazolam group, there were 2 cases of excessive sedation with fall of tongue and abdominal distension, including 1 case of aspiration, 1 case receiving intubation due to refractory hypoxemia and 1 case due to unconsciousness. In dexmedetomidine group, there were 2 cases of bradycardia, 1 case of intubation due to refractory hypoxemia. In control group, 4 cases underwent intubation due to refractory hypoxemia. CONCLUSIONS: Non-invasive mechanical ventilation is an important respiratory support technology for patients with severe COVID-19. Appropriate sedation can increase the efficiency of non-invasive mechanical ventilation. Dexmedetomidine is more effective and safer than midazolam in these patients, but attention should be paid to HR and blood pressure monitoring.

Role of c-Abl and nephrin in podocyte cytoskeletal remodeling induced by angiotensin II.

Our previous study showed that angiotensin II (Ang II) exposure diminished the interaction between nephrin and c-Abl, then c-Abl mediated SHIP2-Akt pathway in the process of podocyte injury in vivo and vitro. However, the relationship between nephrin and c-Abl was unknown. Recently, various studies showed that nephrin was required for cytoskeletal remodeling in glomerular podocytes. But its specific mechanisms remain incompletely understood. As a nonreceptor tyrosine kinase involved in cytoskeletal regulation, c-Abl may be a candidate of signaling proteins interacting with Src homology 2/3 (SH2/SH3) domains of nephrin. Therefore, it is proposed that c-Abl contributes to nephrin-dependent cytoskeletal remodeling of podocytes. Herein, we observed that nephrin-c-Abl colocalization were suppressed in glomeruli of patients with proteinuria. Next, CD16/7-nephrin and c-Abl vectors were constructed to investigate the nephrin-c-Abl signaling pathway in podocyte actin-cytoskeletal remodeling. The disorganized cytoskeleton stimulated by cytochalasin D in COS7 cells was dramatically restored by co-transfection with phosphorylated CD16/7-nephrin and c-Abl full-length constructs. Further, co-immunoprecipitation showed that phosphorylated CD16/7-nephrin interacted with wild-type c-Abl, but not with SH2/SH3-defective c-Abl. These findings suggest that phosphorylated nephrin is able to recruit c-Abl in a SH2/SH3-dependent manner and detached c-Abl from dephosphorylated nephrin contributes to cytoskeletal remodeling in podocytes.