RESUMO
Acute lung injury (ALI) is a life-threatening lung change, and 40% of ALI cases result from sepsis. However, the effective treatment for sepsis-induced ALI is limited. It is urgent to explore novel therapeutic targets for ALI caused by sepsis. Anti-inflammatory therapy is a potential effective treatment for sepsis-induced ALI. Toll-like/Interleukin-1 receptor regulator (TILRR) could trigger aberrant inflammatory responses. Nevertheless, the role of TILRR in sepsis-induced ALI remains unknown. Besides, the phosphatidylinositol 3'kinase/protein kinase B (PI3K/Akt) pathway exerts protective effect on sepsis-induced ALI. Thus, the primary aim of the current study was to investigate whether TILRR contributed to sepsis-induced ALI by the PI3K/Akt pathway. To construct the sepsis-induced ALI model, human pulmonary microvascular endothelial cells (HPMVECs) were treated with lipopolysaccharide (LPS). Besides, the mRNA levels and protein levels were determined by quantitative reverse transcription-PCR (qPCR) and Western blot (WB), respectively. Moreover, cell proliferation was identified by the Cell Counting Kit-8 (CCK-8) assay and Annexin V was utilized to detect apoptosis. Furthermore, levels of proinflammatory cytokines and oxidative stress were tested by the enzyme-linked immunosorbent assay (ELISA) while reactive oxygen species (ROS) was determined by the flow cytometer. Results indicated that TILRR was upregulated to suppress the proliferation and induce apoptosis of HPMVECs under LPS treatment. Besides, TILRR induced aberrant inflammatory responses and oxidative stress in HPMVECs under LPS treatment. Mechanistically, TILRR regulated proliferation, apoptosis, inflammatory responses, and oxidative stress in LPS-treated HPMVECs through inactivating the PI3K/Akt pathway. In summary, TILRR aggravated sepsis-induced ALI by suppressing the PI3K/Akt pathway. These results could provide novel therapy targets for sepsis-induced ALI.
RESUMO
Aims: Clinical studies showed that the use of probiotics during critical illness reduced nosocomial infection and improved clinical outcome. However, the functional mechanisms of probiotics is remains unclear. Therefore the aim of current study is to explore the protective effects and understand the underlying mechanisms for the beneficial effects of live combined Bacillus subtilis and Enterococcus faecium (LCBE) in cecal ligation puncture (CLP)-induced sepsis. Methods and Results: Seven-week-old C57BL/6J mice were divided into three groups: sham group (6 mice), CLP-control group (20 mice, pretreatment with saline for 7 days before CLP surgery) and CLP-probiotics group (14 mice, pretreatment with LCBE enteric-coated capsules for 7 days before CLP surgery). In survival experiment, mice were monitored for 7 days after CLP. After the procedure, mice were sacrificed, and, serum, and peritoneal lavage fluid were collected and intestinal ileal samples were harvested. Results: Our results showed that the mortality was significantly reduced in mice CLP-probiotics group vs. CLP-control group (P < 0.05). Also, treatment CLP-probiotics group decreased the injury scores CLP-probiotics group when compared to CLP-control group. Additionally, levels of pro-inflammatory cytokines IL-6 and TNF-α levels in the serum and intestinal ileal tissues of CLP-probiotics group were reduced when compared to CLP-control group (P < 0.05). However, no significant differences in anti-inflammatory levels of IL-10 and TGF-ß1 were observed between CLP-control and CLP-probiotic groups. Furthermore, our experiments showed that that probiotic treatment suppressed the macrophage activation and transformation from M-type to M1-type, inhibited the mast cells (MCs) degranulation, and activation of AKT (kinase B) pathway. Conclusion: In conclusion, our data shows that probiotics have a protective role in CLP septic mice through reducing intestinal inflammation, altering macrophage polarization and MCs degranulation, and regulating AKT signaling. Significance and Impact of Study: This study demonstrated the protective effects and mechanisms involved in the protective role of live combined Bacillus subtilis and Enterococcus faecium (LCBE) in CLP-induced septic mice model.