FVIIa (Factor VIIa) Induces Biased Cytoprotective Signaling in Mice Through the Cleavage of PAR (Protease-Activated Receptor)-1 at Canonical Arg41 (Arginine41) Site.
FVIIa (因子VIIa) 通过典型Arg41 (精氨酸 41) 位点的PAR (蛋白酶激活受体)-1 裂解诱导小鼠中偏倚的细胞保护信号。
- 作者列表："Kondreddy V","Pendurthi UR","Xu X","Griffin JH","Rao LVM
OBJECTIVE:Recent studies showed that FVIIa (factor VIIa), upon binding to EPCR (endothelial cell protein C receptor), elicits endothelial barrier stabilization and anti-inflammatory effects via activation of PAR (protease-activated receptor)-1-mediated signaling. It is unknown whether FVIIa induces PAR1-dependent cytoprotective signaling through cleavage of PAR1 at the canonical site or a noncanonical site, similar to that of APC (activated protein C). Approach and Results: Mouse strains carrying homozygous R41Q (canonical site) or R46Q (noncanonical site) point mutations in PAR1 (QQ41-PAR1 and QQ46-PAR1 mice) were used to investigate in vivo mechanism of PAR1-dependent pharmacological beneficial effects of FVIIa. Administration of FVIIa reduced lipopolysaccharide-induced inflammation, barrier permeability, and VEGF (vascular endothelial cell growth factor)-induced barrier disruption in wild-type (WT) and QQ46-PAR1 mice but not in QQ41-PAR1 mice. In vitro signaling studies performed with brain endothelial cells isolated from WT, QQ41-PAR1, and QQ46-PAR1 mice showed that FVIIa activation of Akt (protein kinase B) in endothelial cells required R41 cleavage site in PAR1. Our studies showed that FVIIa cleaved endogenous PAR1 in endothelial cells, and FVIIa-cleaved PAR1 was readily internalized, unlike APC-cleaved PAR1 that remained on the cell surface. Additional studies showed that pretreatment of endothelial cells with FVIIa reduced subsequent thrombin-induced signaling. This process was dependent on β-arrestin1. CONCLUSIONS:Our results indicate that in vivo pharmacological benefits of FVIIa in mice arise from PAR1-dependent biased signaling following the cleavage of PAR1 at the canonical R41 site. The mechanism of FVIIa-induced cytoprotective signaling is distinctly different from that of APC. Our data provide another layer of complexity of biased agonism of PAR1 and signaling diversity.
目的: 最近的研究表明，FVIIa (因子VIIa)，在结合EPCR (内皮细胞蛋白C受体)，通过激活PAR (蛋白酶激活受体)-1 介导的信号传导引发内皮屏障稳定和抗炎作用。尚不清楚FVIIa是否通过在规范位点或非规范位点切割PAR1 诱导PAR1-dependent细胞保护信号，类似于APC (活化蛋白C)。方法和结果: 携带PAR1 (QQ41-PAR1 和QQ46-PAR1 小鼠) 纯合R41Q (经典位点) 或R46Q (非经典位点) 点突变的小鼠品系用于研究FVIIa的PAR1-dependent药理有益作用的体内机制。给予FVIIa减少脂多糖诱导的炎症，屏障通透性和VEGF (血管内皮细胞生长因子) 诱导的野生型 (WT) 屏障破坏QQ46-PAR1 只小鼠，但QQ41-PAR1 只小鼠没有。用从WT、QQ41-PAR1 和QQ46-PAR1 小鼠分离的脑内皮细胞进行的体外信号传导研究表明，内皮细胞中Akt (蛋白激酶B) 的FVIIa活化需要par1 中的R41 切割位点。我们的研究表明，FVIIa在内皮细胞中切割了内源性PAR1，FVIIa切割的PAR1 很容易内化，不像APC切割的PAR1 保留在细胞表面。另外的研究表明，用FVIIa预处理内皮细胞减少了随后的凝血酶诱导的信号传导。该过程依赖于 β-arrestin1。 结论: 我们的结果表明，FVIIa在小鼠中的体内药理学益处源于在经典R41 位点切割PAR1 后的PAR1-dependent偏倚信号传导。FVIIa诱导的细胞保护性信号传导的机制与APC明显不同。我们的数据提供了PAR1 和信号多样性的另一层有偏见的激动性的复杂性。
METHODS::The antimicrobial functions of neutrophils are facilitated by a defensive armamentarium of proteins stored in granules, and by the formation of neutrophil extracellular traps (NETs). However, the toxic nature of these structures poses a threat to highly vascularized tissues, such as the lungs. Here, we identified a cell-intrinsic program that modified the neutrophil proteome in the circulation and caused the progressive loss of granule content and reduction of the NET-forming capacity. This program was driven by the receptor CXCR2 and by regulators of circadian cycles. As a consequence, lungs were protected from inflammatory injury at times of day or in mouse mutants in which granule content was low. Changes in the proteome, granule content and NET formation also occurred in human neutrophils, and correlated with the incidence and severity of respiratory distress in pneumonia patients. Our findings unveil a 'disarming' strategy of neutrophils that depletes protein stores to reduce the magnitude of inflammation.
METHODS::Pneumonia is a common respiratory infectious disease that involves the inflammation of the pulmonary parenchyma. Periodontal disease is widespread and correlated with pneumonia. However, the relationship between periodontal treatment and clinical infectious outcomes in patients with pneumonia has remained undetermined. The aim of this study was to investigate the association between periodontal treatment and the risk of pneumonia events in the Taiwanese population. A nationwide population-based cohort study was conducted using data from the Taiwanese National Health Insurance Research Database (NHIRD). A total of 49,400 chronic periodontitis patients who received periodontal treatment from 2001 to 2012 were selected. In addition, 49,400 healthy individuals without periodontal diseases were picked randomly from the general population after propensity score matching according to age, gender, monthly income, urbanization, and comorbidities. The Cox proportional hazard regression analysis was adopted to assess the hazard ratio (HR) of pneumonia between the periodontal treatment cohort and the comparison cohort. The average ages of the periodontal treatment and comparison groups were 44.25 ± 14.82 years and 44.15 ± 14.5 years, respectively. The follow up durations were 7.66 and 7.41 years for the periodontal treatment and comparison groups, respectively. We found 2504 and 1922 patients with newly diagnosed pneumonia in the comparison cohort and the periodontal treatment cohort, respectively. The Kaplan-Meier plot revealed that the cumulative incidence of pneumonia was significantly lower over the 12 year follow-up period in the periodontal treatment group (using the log-rank test, p < 0.001). In conclusion, this nationwide population-based study indicated that the patients with periodontal treatment exhibited a significantly lower risk of pneumonia than the general population.
METHODS:OBJECTIVE:To describe the treatment of community-acquired pneumonia (CAP) in children under five years in Tanzania. METHODS:Between January and December 2017, children aged 2-59 months with chest radiography-confirmed CAP were enrolled. The parents were interviewed to collect information on the patients and home-based medication. Clinical information was derived from the patient files. Nasopharyngeal swab and blood samples were collected for isolation of the causative pathogens. Swab samples were analysed by quantitative PCR whereas blood samples were tested using BacT/Alert 3D. RESULTS:Overall, 109 children with CAP were included in this analysis. Provision of care to most children was delayed (median = 4.6 days). A quarter (26.6%) were given unprescribed/leftover antibiotics at home. Only one child had positive bacterial culture. Referrals were associated with nasopharyngeal carriage of Streptococcus pneumoniae (p = 0.003) and Haemophilus influenzae (p = 0.004). Of all admitted children, more than a quarter (n = 29) did not need to be hospitalised and inappropriately received injectable instead of oral antibiotics. CONCLUSION:We found high rates of home treatment, particularly with antibiotics. Appropriate health care was delayed for most children because of home treatment. Efforts are needed at the community level to improve awareness of antimicrobial resistance.