Quercetin attenuates inflammation in human macrophages and adipocytes exposed to macrophage-conditioned media

Abstract

Background: Obesity is linked to chronic inflammation in white adipose tissue, which is exacerbated by infiltrating macrophages (MFs). We recently demonstrated that an extract from grape powder (GPE), which is abundant in quercetin (QUE), reduced inflammation in human MFs and prevented MF-mediated inflammation and insulin resistance in human adipocytes. However, we did not know how QUE individually affected these outcomes. Objective and design: We examined the extent to which QUE prevents inflammation in human MFs (that is, differentiated U937 cell line) and cross-talk with human adipocytes (that is, primary cultures of newly differentiated human adipocytes). Methods and results: Treatment of MFs with QUE attenuated the basal expression of inflammatory genes, such as tumor necrosis factor-a, interleukin (IL)-6, IL-8, IL-1b and interferon-g inducible protein-10, and cyclooxygenase-2, a marker of prostaglandin production. QUE also attenuated the abundance of phosphorylated c-Jun N-terminal kinase (JNK) and c-Jun, and IkBa degradation in MFs. Furthermore, conditioned media (CM) obtained from MFs treated with QUE decreased the capacity of this CM to inflame adipocytes and cause insulin resistance as evidenced by decreased: (1) inflammatory gene expression, (2) phosphorylation of JNK and c-Jun, (3) serine residue 307 phosphorylation of insulin receptor substrate (IRS)-1, 4) protein tyrosine phosphatase-1B gene expression and 5) suppression of insulin-stimulated glucose uptake. Conclusion: Taken together, these data suggest that QUE is one of the bioactive components of GPE that prevents inflammation in MFs and MF-mediated insulin resistance in adipocytes.

Effect of Quercetin on the Endocrine Pancreas of the Experimentally Induced Diabetes in Male Albino Rats: A Histological and Immunohistochemical Study

“…In QCT-treated group in this study, the charcoal labeled macrohages were markedly decreased all over the pancreatic sections, especially in the islet region compared to the diabetic group suggested that QCT had a protective role as anti-inflammatory in decreasing the mediators of inflammation in diabetes. This finding was in the same line of Overman et al [33], who reported that QCT reduced the inflammation in human and prevent the mediator of this inflammation.…”

Natural Flavonoids in StAR Gene Expression and Testosterone Biosynthesis in Leydig Cell Aging

“…The observations were enhanced by the study on the inhibitory effects of quercetin on ROS-induced MAPK activation and COX2 expression (Huang et al, 2006). The inhibition of MAPKs by quercetin was associated with the reductions in inflammatory cytokines, such as IL-1 and TNF- (Overman et al, 2011). In addition, quercetin is able to block the COX2-TBXAS-TBX A2-receptor signaling pathway by inhibition of TBX A2 formation (Garcia-Saura et al, 2005;Sheu et al, 2004).…”

Treating acute cystitis with biodegradable micelle-encapsulated quercetin

“…One of the most important applications of nanotechnology in medicine is using nanoparticles to deliver hydrophobic drugs to create aqueous formulations for these water soluble-poor drugs. QU has great prospects in the treatment of inflammation, 31 but it is limited in its medical application due to poor water solubility. To address this challenge, the use of liposomes to encapsulate QU has been described.…”

“…QU is a well recognized anti-inflammation agent. 31 In this paper, QU was used to treat acute cystitis. Results indicated that QU/MPEG-PCL micelle treatment can efficiently reduce the edema and inflammatory cell infiltration of the bladder in an E. coli-induced acute cystitis model.…”