Urinary Trypsin Inhibitor Protects Tight Junctions of Septic Pulmonary Capillary Endothelial Cells by Regulating the Functions of Macrophages

Fe-Capsaicin Nanozymes Attenuate Sepsis-Induced Acute Lung Injury via NF-κB Signaling

Background

In sepsis, the lungs are one of the most severely affected organs, usually resulting in acute lung injury (ALI). Capsaicin (CAP) is a natural compound found in chili peppers that has pain-relieving and anti-inflammatory properties. Here, we report that nanoparticles containing capsaicin and iron (Fe-CAP NPs) exhibited anti-inflammatory effects in the treatment of ALI.

Methods

The morphological characteristics of nanozymes were detected. RAW 264.7 cells were divided into four groups: control, lipopolysaccharide (LPS), CAP+LPS and Fe-CAP+LPS groups. The expression of inducible nitric oxide synthase (iNOS), transforming growth factor-β (TGF-β), and tumor necrosis factor-α (TNF-α) was assessed by immunofluorescence, Western blot, and enzyme-linked immunosorbent assay (ELISA). Nuclear factor kappa-B (NF-κB) expression was determined by Western blot. C57 mice were divided into control, LPS, CAP+LPS and Fe-CAP+LPS groups. Interleukin-6 (IL-6) and iNOS expression in the lung was detected by Western Blot. IL-6 and TNF-α expression in serum was detected by ELISA. Extravasated Evans blue, histopathological evaluation and wet-to-dry (W/D) weight ratio were used to assess pulmonary capillary permeability. The blood and major organs (heart, liver, spleen, lung and kidney) of mice were tested for the toxicity of Fe-CAP NPs.

Results

In the LPS group, TNF-α, iNOS, p-NF-κB and p-IKBα expression increased. However, their expression was significantly decreased in the Fe-CAP+LPS group. TGF-β expression showed the opposite trend. In vivo, IL-6 and iNOS expression was notably increased in the lungs of LPS group of mice but decreased with Fe-CAP pretreatment. Fe-CAP significantly ameliorated lung EB leakage, improved the histopathology of lung tissue and reduced the W/D weight ratio. The nanoparticles showed non-cytotoxicity, when studying these biological activities.

Conclusion

Fe-CAP NPs could alleviated inflammation by inhibiting the expression of pro-inflammatory factors in macrophages, increasing the expression of anti-inflammatory factors, and alleviating lung tissue damage.

MYOSIN LIGHT CHAIN KINASE DELETION WORSENS LUNG PERMEABILITY AND INCREASES MORTALITY IN PNEUMONIA-INDUCED SEPSIS

ABSTRACT

Increased epithelial permeability in sepsis is mediated via disruptions in tight junctions, which are closely associated with the perijunctional actin-myosin ring. Genetic deletion of myosin light chain kinase (MLCK) reverses sepsis-induced intestinal hyperpermeability and improves survival in a murine model of intra-abdominal sepsis. In an attempt to determine the generalizability of these findings, this study measured the impact of MLCK deletion on survival and potential associated mechanisms following pneumonia-induced sepsis. MLCK -/- and wild-type mice underwent intratracheal injection of Pseudomonas aeruginosa . Unexpectedly, survival was significantly worse in MLCK -/- mice than wild-type mice. This was associated with increased permeability to Evans blue dye in bronchoalveolar lavage fluid but not in tissue homogenate, suggesting increased alveolar epithelial leak. In addition, bacterial burden was increased in bronchoalveolar lavage fluid. Cytokine array using whole-lung homogenate demonstrated increases in multiple proinflammatory and anti-inflammatory cytokines in knockout mice. These local pulmonary changes were associated with systemic inflammation with increased serum levels of IL-6 and IL-10 and a marked increase in bacteremia in MLCK -/- mice. Increased numbers of both bulk and memory CD4 + T cells were identified in the spleens of knockout mice, with increased early and late activation. These results demonstrate that genetic deletion of MLCK unexpectedly increases mortality in pulmonary sepsis, associated with worsened alveolar epithelial leak and both local and systemic inflammation. This suggests that caution is required in targeting MLCK for therapeutic gain in sepsis.

Ulinastatin alleviates pulmonary edema by reducing pulmonary permeability and stimulating alveolar fluid clearance in a rat model of acute lung injury

Objectives

Previous studies have shown that ulinastatin (UTI) alleviates pulmonary edema in acute lung injury (ALI) caused by lipopolysaccharide (LPS), although the mechanism behind this action is uncertain. This research aimed to identify the fundamental mechanism by which UTI alleviates pulmonary edema.

Materials and Methods

We established a model of acute lung injury (ALI) in rats by using LPS as the inciting agent.The control, LPS, and LPS+UTI groups were each comprised of a specific number of randomly selected Wistar rats. We evaluated lung injury and determined pulmonary edema. The concentrations of TNF-α, IL-1β and IL-6 in BALF and the expression levels of α1Na, k-ATPase, β1Na, K-AtPase, α-ENaC, β-ENaC, γ-ENaC, Zonula occludens (ZO)-1, Occludin, Caludin-5, PI3K, Akt, TLR4, MyD88 and NF-ƘBwere identified in lung tissues.

Results

The presence of UTI was associated with a reduction in lung pathological alterations, lung injury scores, the lung W/D ratio, and MPO activity, in addition to the improved gas exchange (P<0.01). Furthermore, UTI alleviated EB leakage and stimulated AFC (P<0.01). Importantly, UTI increased the expression of ZO-1, Occludin, Caludin-5, α1Na, K-ATPase, β1Na, K-AtPase, α-ENaC, β-ENaC, and γ-ENaC (P<0.01). Furthermore, UTI inhibited the inflammatory response, enhanced the expression of PI3K and Akt and hindered TLR4, MyD88, and NF-ƘB expression (P<0.01) in lung tissues.

Conclusion

Our results demonstrated that UTI attenuated pulmonary edema by reducing pulmonary permeability and promoting AFC through inhibiting the inflammatory response, and the mechanism is related to promoting PI3K/Akt signaling pathways and suppressing TLR4/MyD88/NF-ƘB signaling pathways.

Lycium barbarum polysaccharides ameliorate LPS-induced inflammation of RAW264.7 cells and modify the behavioral score of peritonitis mice

In the present study, the anti-inflammatory effect of Lycium barbarum polysaccharide (LBP) and the possible molecular mechanism thereof were examined, so as to perceive the pharmacological action of LBP. With acute peritonitis in mice as the inflammatory model, the protective effect of LBP on peritonitis mice was evaluated by recording the effect of behavioral scores, studying the pathological damage of intestine and liver, and detecting the levels of inflammatory cytokines. Additionally, by establishing an lipopolysaccharide (LPS)-induced RAW264.7 macrophage model, the effect of LBP on RAW264.7 cell phenotype and culture supernatant inflammatory markers was observed. Finally, the activation of inflammation-related target genes, such as iNOS, Toll-like receptor 4 (TLR4), nuclear factor-κB (NF-κB) p65, and IκBα, were further detected. The results reveal that pretreatment with LBP could decrease the behavioral score of inflammatory mice, inhibit the secretion of pro-inflammatory factors, and reduce liver and intestine injury. LBP can regulate the effect of lipopolysaccharide on the polarization of RAW264.7 cells, and reduce the production of NO and cytokines (TNF-α, IL-1β, IL-6). Further, LBP pretreatment was found to be able to significantly reduce the expression of iNOS, TLR4, NF-κB p65, and IκBα in macrophages. The present research provides evidence that LBP exerts potential anti-inflammatory activity in LPS-induced RAW264.7 macrophages via inhibiting TLR4 and NF-κB inflammatory sites and improving the behavior score of peritonitis mice. PRACTICAL APPLICATIONS: In recent years, the number of deaths worldwide has continued to rise as a result of inflammation. Despite said rise in deaths, many synthetic drugs with anti-inflammatory properties are significantly expensive and also have a host of side effects. Thus, the development of new anti-inflammatory drugs derived from medicinal plants has broad application potential. As such, in the present study, lipopolysaccharide (LPS)-induced macrophages were used to establish inflammatory cell models to verify the anti-inflammatory effect of Lycium barbarum polysaccharides (LBP). Findings were made that LBP could reduce the expression levels of inflammatory cytokines and NO by regulating macrophage polarization and NF-κB translocation, and thus, could exert anti-inflammatory activity. In addition, by intraperitoneal injection of LPS to establish peritonitis mice models, LBP pretreatment was found to have significantly modified the behavioral score of mice, while decreasing the secretion of inflammatory factors and the damage to several organs. The present study provides a basis for further understanding the effects of LBP in acute inflammation.