OBJECTIVE: In this study, we aim to investigate the involvement of heme oxygenase-1 (HO-1) in the anti-inflammatory effects of ZnC in lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophages.
MATERIALS AND METHODS: We used immunoblotting analysis to evaluate the involvement of HO-1 in the anti-inflammatory effects of ZnC and the signaling pathway involved was measured using Dual luciferase reporter assay.
RESULTS: Results from immunoblotting analysis demonstrated that pretreatment of cells with ZnC enhanced the expression of HO-1 in RAW 264.7 cells. Pretreatment of cells with HO-1 inhibitor (tin protoporphyrin IX dichloride) significantly attenuated the inhibitory effects of ZnC on nitric oxide (NO) production, inducible nitric oxide synthase (iNOS) expression and NF-κB activation in LPS-induced RAW 264.7 cells, suggesting that HO-1 play an important role in the suppression of inflammatory responses induced by ZnC. Furthermore, results from co-immunoprecipitation of Nrf2 and Keap1 and dual luciferase reporter assay showed that pretreatment of ZnC was able to activate the Nrf2 signaling pathway. Treatment of cells with p38 inhibitor (SB203580), c-Jun N-terminal kinase inhibitor (SP600125), and MEK 1/2 inhibitor (U0126) did not significantly suppress the induction of HO-1 by ZnC. Moreover, our present findings suggest that the effects of ZnC on NO production, HO-1 expression, and Nrf2 activation were attributed to its Zn subcomponent, but not l-carnosine.
CONCLUSION: Pretreatment with ZnC was able to activate Nrf2/HO-1 signaling pathway, thus suppressing the expression of inflammatory mediators, such as NO and iNOS in LPS-induced RAW 264.7 cells.
OBJECTIVE: To investigate the effect of zerumbone on HDM extract-induced airway epithelial barrier dysfunction.
MATERIALS AND METHODS: Human bronchial epithelial cells 16HBE14o- were incubated with 100 μg/mL HDM extract and treated with non-cytotoxic concentrations of zerumbone (6.25 μM, 12.5 μM, and 25 μM) for 24 h. The epithelial junctional integrity and permeability were evaluated through transepithelial electrical resistance (TEER) and fluorescein isothiocynate (FITC)-Dextran permeability assays, respectively. The localization of junctional proteins, occludin and zona occludens (ZO)-1, was studied using immunofluorescence (IF) while the protein expression was measured by western blot.
RESULTS: Zerumbone inhibited changes in junctional integrity (6.25 μM, p ≤ .05; 12.5 μM, p ≤ .001; 25 μM, p ≤ .001) and permeability (6.25 μM, p ≤ .05; 12.5 μM, p ≤ .01; 25 μM, p ≤ .001) triggered by HDM extract in a concentration-dependent manner. This protective effect could be explained by the preservation of occludin (12.5 μM, p ≤ .01 and 25 μM, p ≤ .001) and ZO-1 (12.5 μM, p ≤ .05 and 25 μM, p ≤ .001) localization, rather than the prevention of their cleavage.
DISCUSSION AND CONCLUSION: Zerumbone attenuates HDM extract-induced epithelial barrier dysfunction which supports its potential application for the treatment of inflammation-driven airway diseases such as asthma.
METHODS: A systematic literature search with no language restriction was performed in electronic databases and preprint repositories to identify eligible studies published up to 29 June 2021. The outcomes of interest were hospital admission and all-cause mortality. A random-effects model was used to estimate the pooled odds ratio (OR) for outcomes of interest with the use of neutralizing monoclonal antibodies relative to nonuse of neutralizing monoclonal antibodies, at 95% confidence intervals (CI).
RESULTS: Our systematic literature search identified nine randomized controlled trials. Three trials had an overall low risk of bias, while four trials had some concerns in the overall risk of bias. The meta-analysis revealed no statistically significant difference in the odds of mortality (pooled OR = 0.69; 95% CI 0.33-1.47), but a statistically significant reduction in the odds of hospital admission (pooled OR = 0.29; 95% CI 0.21-0.42), with the administration of a neutralizing monoclonal antibody among patients with COVID-19, relative to non-administration of a neutralizing monoclonal antibody, at the current sample size.
CONCLUSION: The reduced risk of hospital admission with neutralizing monoclonal antibodies use suggests that the timing of neutralizing antibodies administration is key in preventing hospital admission and, ultimately, death. Future randomized trials should aim to determine if the clinical outcomes with neutralizing monoclonal antibodies differ based on serostatus.