TY - JOUR
T1 - Oxidative stress induces expression of the toll-like receptors (TLRs) 2 and 4 in the human peripheral blood mononuclear cells
T2 - Implications for metabolic inflammation
AU - Akhter, Nadeem
AU - Madhoun, Ashraf
AU - Arefanian, Hossein
AU - Wilson, Ajit
AU - Kochumon, Shihab
AU - Thomas, Reeby
AU - Shenouda, Steve
AU - Al-Mulla, Fahd
AU - Ahmad, Rasheed
AU - Sindhu, Sardar
N1 - © Copyright by the Author(s). Published by Cell Physiol Biochem Press.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - BACKGROUND/AIMS: Innate immune toll-like receptors (TLRs) are emerging as nutrient sensors. Oxidative stress in the adipose tissue in obesity acts as a critical early trigger of altered pathophysiology. TLR2/TLR4 adipose upregulation has been associated with insulin resistance in humans; however, it remains unclear whether oxidative stress can modulate expression of TLR2/4 and related immune-metabolic regulators (IRF3/5) in immune cells. We, therefore, assessed their expression along with proinflammatory cytokines in the human PBMC following induction of oxidative stress.METHODS: PBMC were isolated from blood of healthy donors using Ficoll-Paque method and cells were treated with H
2O
2 to induce oxidative stress. ROS was measured by DCFH-DA assay. Target gene and protein expression was determined using real-time RT-PCR and flow cytometry/confocal microscopy, respectively. TLR2/4 expression by H
2O
2 in presence of ROS-inhibitors or leptin/LPS/fatty acids was also assessed. Expression of phosphorylated/total ERK1/2, c-Jun, p38, and NF-κB was determined by western blotting. The data (mean±SEM) were compared using unpaired student's t-test or ANOVA; all P-values <0.05 were considered significant.
RESULTS: TLR2/4 mRNA/protein expression was elevated by oxidative stress in PBMC compared to controls (P<0.001). This induction was abrogated by apocynin/N-acetyl cysteine treatments (P<0.01). H
2O
2-induced TLR2/4 gene expression was further enhanced by leptin, LPS, oleate, or palmitate (P<0.05). Oxidative stress also promoted expression of IRF3/5 and proinflammatory cytokines including IFN-γ, IL-1β, IL-6, TNF-α, and MCP-1/CCL2. This oxidative stress in PBMC involved MAPK/NF-κB dependent signaling.
CONCLUSION: Taken together, oxidative stress upregulates expression of TLR2/4, IRF3/5 and signature proinflammatory cytokines in PBMC, involving MAPK/NF-κB dependent signaling, all of which may have implications for metabolic inflammation.
AB - BACKGROUND/AIMS: Innate immune toll-like receptors (TLRs) are emerging as nutrient sensors. Oxidative stress in the adipose tissue in obesity acts as a critical early trigger of altered pathophysiology. TLR2/TLR4 adipose upregulation has been associated with insulin resistance in humans; however, it remains unclear whether oxidative stress can modulate expression of TLR2/4 and related immune-metabolic regulators (IRF3/5) in immune cells. We, therefore, assessed their expression along with proinflammatory cytokines in the human PBMC following induction of oxidative stress.METHODS: PBMC were isolated from blood of healthy donors using Ficoll-Paque method and cells were treated with H
2O
2 to induce oxidative stress. ROS was measured by DCFH-DA assay. Target gene and protein expression was determined using real-time RT-PCR and flow cytometry/confocal microscopy, respectively. TLR2/4 expression by H
2O
2 in presence of ROS-inhibitors or leptin/LPS/fatty acids was also assessed. Expression of phosphorylated/total ERK1/2, c-Jun, p38, and NF-κB was determined by western blotting. The data (mean±SEM) were compared using unpaired student's t-test or ANOVA; all P-values <0.05 were considered significant.
RESULTS: TLR2/4 mRNA/protein expression was elevated by oxidative stress in PBMC compared to controls (P<0.001). This induction was abrogated by apocynin/N-acetyl cysteine treatments (P<0.01). H
2O
2-induced TLR2/4 gene expression was further enhanced by leptin, LPS, oleate, or palmitate (P<0.05). Oxidative stress also promoted expression of IRF3/5 and proinflammatory cytokines including IFN-γ, IL-1β, IL-6, TNF-α, and MCP-1/CCL2. This oxidative stress in PBMC involved MAPK/NF-κB dependent signaling.
CONCLUSION: Taken together, oxidative stress upregulates expression of TLR2/4, IRF3/5 and signature proinflammatory cytokines in PBMC, involving MAPK/NF-κB dependent signaling, all of which may have implications for metabolic inflammation.
KW - Cells, Cultured
KW - Humans
KW - Inflammation/genetics
KW - Interferon Regulatory Factor-3/genetics
KW - Interferon Regulatory Factors/genetics
KW - Leukocytes, Mononuclear/metabolism
KW - Oxidative Stress
KW - Reactive Oxygen Species/metabolism
KW - Toll-Like Receptor 2/genetics
KW - Toll-Like Receptor 4/genetics
KW - Up-Regulation
UR - http://www.scopus.com/inward/record.url?scp=85067198188&partnerID=8YFLogxK
U2 - 10.33594/000000117
DO - 10.33594/000000117
M3 - Article
C2 - 31162913
AN - SCOPUS:85067198188
VL - 53
SP - 1
EP - 18
JO - Cellular Physiology and Biochemistry
JF - Cellular Physiology and Biochemistry
SN - 1015-8987
IS - 1
ER -