1
|
Harada M, Su-Harada K, Kimura T, Ono K, Ashida N. Sustained activation of NF-κB through constitutively active IKKβ leads to senescence bypass in murine dermal fibroblasts. Cell Cycle 2024:1-20. [PMID: 38461418 DOI: 10.1080/15384101.2024.2325802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/26/2024] [Indexed: 03/12/2024] Open
Abstract
Although the transcription factor nuclear factor κB (NF-κB) plays a central role in the regulation of senescence-associated secretory phenotype (SASP) acquisition, our understanding of the involvement of NF-κB in the induction of cellular senescence is limited. Here, we show that activation of the canonical NF-κB pathway suppresses senescence in murine dermal fibroblasts. IκB kinase β (IKKβ)-depleted dermal fibroblasts showed ineffective NF-κB activation and underwent senescence more rapidly than control cells when cultured under 20% oxygen conditions, as indicated by senescence-associated β-galactosidase (SA-β-gal) staining and p16INK4a mRNA levels. Conversely, the expression of constitutively active IKKβ (IKKβ-CA) was sufficient to drive senescence bypass. Notably, the expression of a degradation-resistant form of inhibitor of κB (IκB), which inhibits NF-κB nuclear translocation, abolished senescence bypass, suggesting that the inhibitory effect of IKKβ-CA on senescence is largely mediated by NF-κB. We also found that IKKβ-CA expression suppressed the derepression of INK4/Arf genes and counteracted the senescence-associated loss of Ezh2, a catalytic subunit of the Polycomb repressive complex 2 (PRC2). Moreover, pharmacological inhibition of Ezh2 abolished IKKβ-CA-induced senescence bypass. We propose that NF-κB plays a suppressive role in the induction of stress-induced senescence through sustaining Ezh2 expression.
Collapse
Affiliation(s)
- Masayuki Harada
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kanae Su-Harada
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takeshi Kimura
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koh Ono
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Noboru Ashida
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| |
Collapse
|
2
|
Meng Z, Hernandez R, Liu J, Gwag T, Lu W, Hsiai TK, Kaul M, Zhou T, Zhou C. HIV Protein Tat Induces Macrophage Dysfunction and Atherosclerosis Development in Low-Density Lipoprotein Receptor-Deficient Mice. Cardiovasc Drugs Ther 2021; 36:201-215. [PMID: 33459922 DOI: 10.1007/s10557-021-07141-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/06/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE HIV infection is consistently associated with an increased risk of atherosclerotic cardiovascular disease, but the underlying mechanisms remain elusive. HIV protein Tat, a transcriptional activator of HIV, has been shown to activate NF-κB signaling and promote inflammation in vitro. However, the atherogenic effects of HIV Tat have not been investigated in vivo. Macrophages are one of the major cell types involved in the initiation and progression of atherosclerosis. We and others have previously revealed the important role of IκB kinase β (IKKβ), a central inflammatory coordinator through activating NF-κB, in the regulation of macrophage functions and atherogenesis. This study investigated the impact of HIV Tat exposure on macrophage functions and atherogenesis. METHODS To investigate the effects of Tat on macrophage IKKβ activation and atherosclerosis development in vivo, myeloid-specific IKKβ-deficient LDLR-deficient (IKKβΔMyeLDLR-/-) mice and their control littermates (IKKβF/FLDLR-/-) were exposed to recombinant HIV protein Tat. RESULTS Exposure to Tat significantly increased atherosclerotic lesion size and plaque vulnerability in IKKβF/FLDLR-/- but not IKKβΔMyeLDLR-/- mice. Deficiency of myeloid IKKβ attenuated Tat-elicited macrophage inflammatory responses and atherosclerotic lesional inflammation in IKKβΔMyeLDLR-/- mice. Further, RNAseq analysis demonstrated that HIV protein Tat affects the expression of many atherosclerosis-related genes in vitro in an IKKβ-dependent manner. CONCLUSIONS Our findings reveal atherogenic effects of HIV protein Tat in vivo and demonstrate a pivotal role of myeloid IKKβ in Tat-driven atherogenesis.
Collapse
Affiliation(s)
- Zhaojie Meng
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Rebecca Hernandez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Jingwei Liu
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Taesik Gwag
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Weiwei Lu
- Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Tzung K Hsiai
- Departments of Medicine and Bioengineering, David Geffen School of Medicine, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, CA, USA
| | - Marcus Kaul
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Tong Zhou
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Changcheng Zhou
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA.
| |
Collapse
|
3
|
Wei SF, Sun JJ, Zhou N, Li XL, Lin Y, Zhang YD, Zhang YR, Wu LY. Protective effect of RNA interference targeting Ikkβ on hepatic fibrosis in rats. J Cell Biochem 2019; 120:18894-18900. [PMID: 31297885 DOI: 10.1002/jcb.29209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/02/2019] [Accepted: 06/04/2019] [Indexed: 11/07/2022]
Abstract
Nuclear factor-κB (NF-κB) is an important regulatory factor in cells. NF-κB has a wide range of biological activities. After activation, it participates in the transcription and regulation of many genes and plays a role in infection, inflammatory response, oxidative stress, cell multiplication, and apoptosis. The activation of the NF-κB signal pathway is dependent on the degradation of the IκB kinase β (IKKβ) complex. IKK β is the key kinase in the NF-κB activation pathway. After inhibition, it can block the activation of NF-κB. IKKβ is a key regulator of NF-κB activation, also an early regulator of inflammation in all stages of the immune response. This study aimed to investigate the effect of IKKβ-siRNA lentivirus vector treatment for hepatic fibrosis of rats. An IKKβ-siRNA expression plasmid was constructed and injected in the tail vein of rats. Then, IKKβ-siRNA distribution in the liver was observed by immunofluorescence, and the quantitative polymerase chain reaction was used to detect inflammation-related and fibrosis-related factors. IKKβ-siRNA lentiviruses could be delivered to the liver and significantly decrease carbon tetrachloride-induced hepatic fibrosis. Furthermore, serum transaminase levels significantly decreased, and inflammation-related and fibrosis-related factors decreased. IKKβ-siRNA can be an effective method of anti-fibrosis gene therapy for liver fibrosis.
Collapse
Affiliation(s)
- Shi-Fang Wei
- Department of Infectious Disease, Lanzhou First People's Hospital, Lanzhou, Gansu, China
| | - Jian-Jun Sun
- Department of Clinical Laboratory, Hospital of Pulmonary Division of Lanzhou, Lanzhou, Gansu, China
| | - Ning Zhou
- Department of Infectious Disease, Lanzhou First People's Hospital, Lanzhou, Gansu, China
| | - Xiang-Lin Li
- Department of Infectious Disease, Lanzhou First People's Hospital, Lanzhou, Gansu, China
| | - Yan Lin
- Department of Infectious Disease, Lanzhou First People's Hospital, Lanzhou, Gansu, China
| | - Yao-Di Zhang
- Department of Infectious Disease, Lanzhou First People's Hospital, Lanzhou, Gansu, China
| | - Yue-Rong Zhang
- Department of Infectious Disease, Lanzhou First People's Hospital, Lanzhou, Gansu, China
| | - Li-Yang Wu
- Department of Infectious Disease, Lanzhou First People's Hospital, Lanzhou, Gansu, China
| |
Collapse
|
4
|
Xie X, Tu J, You H, Hu B. Design, synthesis, and biological evaluation of novel EF24 and EF31 analogs as potential IκB kinase β inhibitors for the treatment of pancreatic cancer. Drug Des Devel Ther 2017; 11:1439-1451. [PMID: 28553074 PMCID: PMC5440027 DOI: 10.2147/dddt.s133172] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Given the important role that inhibitory kappa B (IκB) kinase β (IKKβ) plays in pancreatic cancer (PC) development and progression, inhibitors targeting IKKβ are believed to be increasingly popular as novel anti-PC therapies. Two synthetic molecules, named EF24 and EF31, exhibited favorable potential in terms of inhibition of both IKKβ activity and PC cell proliferation. Aiming to enhance their cellular efficacy and to analyze their structure–activity relationship, four series of EF24 and EF31 analogs were designed and synthesized. Through kinase activity and vitality screening of cancer cells, D6 displayed excellent inhibition of both IKKβ activity and PC cell proliferation. Additionally, multiple biological evaluations showed that D6 was directly bound to IKKβ and significantly suppressed the activation of the IKKβ/nuclear factor κB pathway induced by tumor necrosis factor-α, as well as effectively inducing cancer cell apoptosis. Moreover, molecular docking and molecular dynamics simulation analysis indicated that the dominant force between D6 and IKKβ comprised hydrophobic interactions. In conclusion, D6 may be a promising therapeutic agent for PC treatment and it also provides a structural lead for the design of novel IKKβ inhibitors.
Collapse
Affiliation(s)
- Xuemeng Xie
- Department of Laparoscopic Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Jinfu Tu
- Department of Laparoscopic Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Heyi You
- Department of Laparoscopic Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Bingren Hu
- Department of Laparoscopic Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| |
Collapse
|
5
|
Helsley RN, Sui Y, Park SH, Liu Z, Lee RG, Zhu B, Kern PA, Zhou C. Targeting IκB kinase β in Adipocyte Lineage Cells for Treatment of Obesity and Metabolic Dysfunctions. Stem Cells 2016; 34:1883-95. [PMID: 26991836 DOI: 10.1002/stem.2358] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/15/2016] [Indexed: 02/06/2023]
Abstract
IκB kinase β (IKKβ), a central coordinator of inflammation through activation of nuclear factor-κB, has been identified as a potential therapeutic target for the treatment of obesity-associated metabolic dysfunctions. In this study, we evaluated an antisense oligonucleotide (ASO) inhibitor of IKKβ and found that IKKβ ASO ameliorated diet-induced metabolic dysfunctions in mice. Interestingly, IKKβ ASO also inhibited adipocyte differentiation and reduced adiposity in high-fat (HF)-fed mice, indicating an important role of IKKβ signaling in the regulation of adipocyte differentiation. Indeed, CRISPR/Cas9-mediated genomic deletion of IKKβ in 3T3-L1 preadipocytes blocked these cells differentiating into adipocytes. To further elucidate the role of adipose progenitor IKKβ signaling in diet-induced obesity, we generated mice that selectively lack IKKβ in the white adipose lineage and confirmed the essential role of IKKβ in mediating adipocyte differentiation in vivo. Deficiency of IKKβ decreased HF-elicited adipogenesis in addition to reducing inflammation and protected mice from diet-induced obesity and insulin resistance. Further, pharmacological inhibition of IKKβ also blocked human adipose stem cell differentiation. Our findings establish IKKβ as a pivotal regulator of adipogenesis and suggest that overnutrition-mediated IKKβ activation serves as an initial signal that triggers adipose progenitor cell differentiation in response to HF feeding. Inhibition of IKKβ with antisense therapy may represent as a novel therapeutic approach to combat obesity and metabolic dysfunctions. Stem Cells 2016;34:1883-1895.
Collapse
Affiliation(s)
- Robert N Helsley
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Yipeng Sui
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Se-Hyung Park
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Zun Liu
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Richard G Lee
- Cardiovascular Antisense Drug Discovery Group, Ionis Pharmaceuticals, Inc., Carlsbad, California, USA
| | - Beibei Zhu
- Department of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Philip A Kern
- Department of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Changcheng Zhou
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA.,Saha Cardiovascular Research Center, University of Kentucky, Lexington, Kentucky, USA
| |
Collapse
|
6
|
Gao Y, Chen X, Fang L, Liu F, Cai R, Peng C, Qi Y. Rhein exerts pro- and anti-inflammatory actions by targeting IKKβ inhibition in LPS-activated macrophages. Free Radic Biol Med 2014; 72:104-12. [PMID: 24721152 DOI: 10.1016/j.freeradbiomed.2014.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 03/25/2014] [Accepted: 04/01/2014] [Indexed: 12/12/2022]
Abstract
Because steroids and cyclooxygenase inhibitors may cause serious side effects, the IκB kinase (IKK) β/nuclear factor-κB (NF-κB) system has become an intriguing candidate anti-inflammatory target. Rhein, the active metabolite of diacerein, possesses anti-inflammatory ability with a gastrointestinal protective effect. However, in a preliminary study, we accidentally found that rhein showed both anti- and proinflammatory activities in lipopolysaccharide (LPS)-activated macrophages. Thus, in this study, we explored the underlying molecular mechanisms of the dual effects of rhein. In LPS-activated macrophages, rhein inhibits NF-κB activation and sequentially suppresses its downstream inducible nitric oxide synthase, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) transcription and supernatant nitric oxide and IL-6 levels by inhibiting IKKβ (IC50 ≈ 11.79μM). But in the meantime, rhein enhances the activity of caspase-1 by inhibiting intracellular (in situ) IKKβ, in turn increasing the IL-1β and high-mobility-group box 1 release, which can be amplified by rhein׳s reductive effect on intracellular superoxide anion. Unexpectedly, it is because of IKKβ inhibition that rhein significantly enhances TNF-α secretion and phagocytosis in macrophages with or without LPS. These results indicate that rhein exerts anti- and proinflammatory activities by targeting IKKβ inhibition, providing a molecular mechanism for the unanticipated role of rhein in macrophages. Furthermore, our study also highlights the potential complications of IKKβ inhibitor (e.g., rhein, diacerein, etc.) application in inflammation disorders, for the overall effects of IKKβ inhibition in various organ systems and disease processes are not easily predictable under all circumstances.
Collapse
Affiliation(s)
- Yuan Gao
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Xi Chen
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Lei Fang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Fen Liu
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Runlan Cai
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Cheng Peng
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
| | - Yun Qi
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China.
| |
Collapse
|
7
|
Jia D, Heng LJ, Yang RH, Gao GD. Fish oil improves learning impairments of diabetic rats by blocking PI3K/AKT/nuclear factor-κB-mediated inflammatory pathways. Neuroscience 2013; 258:228-37. [PMID: 24252320 DOI: 10.1016/j.neuroscience.2013.11.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/25/2013] [Accepted: 11/07/2013] [Indexed: 01/15/2023]
Abstract
Previous research has demonstrated that diabetes induces learning and memory deficits. However, the mechanism of memory impairment induced by diabetes is poorly understood. Dietary fatty acids, especially polyunsaturated fatty acids, have been shown to enhance learning and memory and prevent memory deficits in various experimental conditions. The present study investigated the effects of fish oil supplementation on the lipid peroxidation, inflammation and neuron apoptosis in the hippocampus of streptozotocin (STZ)-induced diabetes rats. The effects of diabetes and fish oil treatment on the spatial learning and memory were also evaluated using the Morris Water Maze. STZ-induced diabetes impaired spatial learning and memory of rats, which was associated with the inflammation, oxidative stress and apoptosis of hippocampal neurons. Fish oil administration ameliorated cognitive deficit, reduced oxidative stress and tumor necrosis factor α (TNF-α), protected the hippocampal neurons by increasing Protein Kinase B (AKT) phosphorylation and decreasing caspase-9 expression. These results suggested that the principle mechanisms involved in the antidiabetic and neuroprotective effect of fish oil were its antioxidant, anti-inflammatory and anti-apoptosis potential, supporting a potential role for fish oil as an adjuvant therapy for the prevention and treatment of diabetic complications.
Collapse
Affiliation(s)
- D Jia
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - L-J Heng
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
| | - R-H Yang
- Department of Nutrition and Food Hygiene, The Ministry of Education Key Laboratory of Hazard Assessment and Control in Special Operational Environment, School of Public Health, The Fourth Military Medical University, Xi'an 710032, PR China.
| | - G-D Gao
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China.
| |
Collapse
|
8
|
Li YY, Yu LF, Zhang LN, Qiu BY, Su MB, Wu F, Chen DK, Pang T, Gu M, Zhang W, Ma WP, Jiang HW, Li JY, Nan FJ, Li J. Novel small-molecule AMPK activator orally exerts beneficial effects on diabetic db/db mice. Toxicol Appl Pharmacol 2013; 273:325-34. [PMID: 24055643 DOI: 10.1016/j.taap.2013.09.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 09/04/2013] [Accepted: 09/08/2013] [Indexed: 01/01/2023]
Abstract
AMP-activated protein kinase (AMPK), which is a pivotal guardian of whole-body energy metabolism, has become an attractive therapeutic target for metabolic syndrome. Previously, using a homogeneous scintillation proximity assay, we identified the small-molecule AMPK activator C24 from an optimization based on the original allosteric activator PT1. In this paper, the AMPK activation mechanism of C24 and its potential beneficial effects on glucose and lipid metabolism on db/db mice were investigated. C24 allosterically stimulated inactive AMPK α subunit truncations and activated AMPK heterotrimers by antagonizing autoinhibition. In primary hepatocytes, C24 increased the phosphorylation of AMPK downstream target acetyl-CoA carboxylase dose-dependently without changing intracellular AMP/ATP ratio, indicating its allosteric activation in cells. Through activating AMPK, C24 decreased glucose output by down-regulating mRNA levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) in primary hepatocytes. C24 also decreased the triglyceride and cholesterol contents in HepG2 cells. Due to its improved bioavailability, chronic oral treatment with multiple doses of C24 significantly reduced blood glucose and lipid levels in plasma, and improved the glucose tolerance of diabetic db/db mice. The hepatic transcriptional levels of PEPCK and G6Pase were reduced. These results demonstrate that this orally effective activator of AMPK represents a novel approach to the treatment of metabolic syndrome.
Collapse
Affiliation(s)
- Yuan-Yuan Li
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Liu HQ, Qiu Y, Mu Y, Zhang XJ, Liu L, Hou XH, Zhang L, Xu XN, Ji AL, Cao R, Yang RH, Wang F. A high ratio of dietary n-3/n-6 polyunsaturated fatty acids improves obesity-linked inflammation and insulin resistance through suppressing activation of TLR4 in SD rats. Nutr Res 2013; 33:849-58. [PMID: 24074743 DOI: 10.1016/j.nutres.2013.07.004] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 06/27/2013] [Accepted: 07/04/2013] [Indexed: 01/07/2023]
Abstract
Dietary ratios of n-3/n-6 polyunsaturated fatty acids (PUFAs) have been implicated in controlling markers of metabolic disorders, including obesity, insulin resistance (IR), inflammation, and lipid profiles, which are also presumed to be partly related to type 2 diabetes mellitus (T2DM). However, molecular mechanisms of the different PUFAs related to metabolic disorders have not been systematically addressed. The present study aimed to investigate the impact of dietary n-3/n-6 PUFA ratios on obesity and IR and, further, to determine the underlying mechanisms. For 16 weeks, 32 SD male rats, randomly divided into four groups (n = 8 per group), received one of the following diets: normal chow, high saturated fatty acid (SFA), high n-3/n-6 PUFA ratio (1∶1, PUFA¹:¹), or low n-3/n-6 PUFA ratio (1∶4, PUFA¹:⁴). Following the experimental diet period, metabolic parameters related to obesity and IR were measured. Compared to SFA diet-fed rats, PUFA¹:¹ diet-fed rats exhibited decreased body and visceral fat weight, lowered blood lipids, and improved glucose tolerance and insulin sensitivity. Interestingly, these changes were accompanied with decreased expression levels of circulating pro-inflammatory cytokines, including tumor necrosis factor α, interleukin-6, and C-reactive protein. Moreover, the TLR4 protein and mRNA levels were markedly down-regulated by PUFA¹:¹ compared with SFA; however, PUFA¹:⁴ diet-fed rats failed to exhibit these changes. Cumulatively, our data highlight a role for a PUFA¹:¹ diet in the prevention of obesity and related metabolic disorders by suppressing the activation of TLR4, a critical modulator of pro-inflammatory cytokines.
Collapse
Affiliation(s)
- Han-Qiang Liu
- Department of Nutrition and Food Hygiene and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|