Pleurotus giganteus (Berk. Karun & Hyde), the giant oyster mushroom inhibits NO production in LPS/H2O2 stimulated RAW 264.7 cells via STAT 3 and COX-2 pathways

Abstract

Background Pleurotus giganteus (Berk. Karunarathna and K.D. Hyde), has been used as a culinary mushroom and is known to have medicinal properties but its potential as an anti-inflammatory agent to mitigate inflammation triggered diseases is untapped. In this study, the molecular mechanism underlying the protective effect of ethanol extract of P. giganteus (EPG) against lipopolysaccharide (LPS) and combination of LPS and hydrogen peroxide (H2O2)-induced inflammation on RAW 264.7 macrophages was investigated.MethodThe effect of EPG on nitric oxide (NO) production as an indicator of inflammation in RAW 264.7 macrophages was estimated based on Griess reaction that measures nitrite level. The expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), NF-kB activating protein (NKAP), signal transducer and activator of transcription 3 protein (STAT 3) and glutathione peroxidase (GPx) genes were assessed using real time reverse transcription polymerase chain reaction (RT-PCR) approach.ResultsEPG (10 μg/ml) showed the highest reduction in the LPS-induced NO production in RAW 264.7 macrophages and significantly suppressed (p < 0.05) the expression iNOS, STAT 3 and COX-2. There was a significant increase (p < 0.05) in combination of LPS and H2O2- induced iNOS production when compared to the LPS-induced iNOS production in RAW 264.7 macrophages and this concurred with the NO production which was attenuated by EPG at 10 μg/ml. A significant (p < 0.05) down regulation was observed in the combination of LPS and H2O2-induced iNOS and GPx expression by EPG.ConclusionsOur data suggest that the anti-inflammatory activity of EPG is mediated via the suppression of the STAT 3 and COX-2 pathways and can serve as potential endogenous antioxidant stimulant.

Differential Induction Pattern Towards Classically Activated Macrophages in Response to an Immunomodulatory Extract from Pleurotus ostreatus Mycelium

“…The polarizing effect of macrophages by Pleurotus fractions has also been reported in another study [ 30 ]. A β-glucan (PCPS) obtained from an extract of Pleurotus cornucopiae fruiting bodies showed a stimulatory effect on both THP-1 human and peritoneal murine macrophages.…”

“…An ethanol extract prepared from basidiocarps of Pleurotus giganteus (Berk. Karun and Hyde) also showed significant suppression of inflammatory markers in a murine macrophage cell line [ 30 ]. The authors described a strong reduction of LPS- and H 2 O 2 -induced pro-inflammatory mediators’ production such as iNOS, STAT and cyclooxygenase-2 (COX-2) despite having a highly activated NO production.…”

“…Both in vitro pro-inflammatory and anti-inflammatory effects have been found for some Pleurotus -derived bioproducts. This raises questions about the relations between mycochemical composition, mushroom growth stage and modulation of macrophage function [ 19 , 29 , 30 , 31 ].…”

Potential role of mushroom beta-glucans in immunity and inflammation in viral infections and COVID-19

“…Studies performed with β-glucans on isolated blood cells or special, so-called transporter cell lines (RAW 264.7), with myeloid cell differentiation and expression of Dectin-1 receptors, demonstrate a pronounced activation of NF-κB and the production of pro-inflammatory cytokines: TNF-α, IL-1β and IL-6 (Kim et al, 2011). However, when cells are treated with inductors that modulate inflammation: LPS, phorbol esters, etc., β-glucans have the opposite effect (Baskaran et al, 2017). The same effects were obtained in animal experiments using fungal β-glucans.…”

Anti-Inflammation and Protective Effects of Anethum graveolens L. (Dill Seeds) on Esophageal Mucosa Damages in Reflux Esophagitis-Induced Rats

“…The LPS-induced macrophage RAW264.7 inflammatory model is commonly used to detect the anti-inflammatory activity of natural drugs [28,29]. RWA264.7 cells are also being used to research gastrointestinal mucosal damage and anti-inflammation mechanisms [30,31].…”