scholarly journals Tetrahydropalmatine Alleviates Hyperlipidemia by Regulating Lipid Peroxidation, Endoplasmic Reticulum Stress, and Inflammasome Activation by Inhibiting the TLR4-NF-κB Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ke Ding ◽  
Linjun Chen ◽  
Jiaqi He ◽  
Jiahong Wang ◽  
Chaohui Yu ◽  
...  

Hyperlipidemia (HLP) is a lipid metabolism disorder that can induce a series of cardiovascular and cerebrovascular diseases, such as atherosclerosis, myocardial infarction, coronary heart disease, and stroke, which seriously threaten human health. Tetrahydropalmatine (THP) is a component of the plant Rhizoma corydalis and has been shown to exert hepatoprotective and anti-inflammatory effects in HLP. However, whether THP regulates lipid peroxidation in hyperlipidemia, endoplasmic reticulum (ER) stress and inflammasome activation and even the underlying protective mechanism against HLP remain unclear. An animal model of HLP was established by feeding a high-fat diet to golden hamsters. Our results showed that THP reduced the body weight and adipose index; decreased the serum content of ALT, AST, TC, TG, and LDL-C; decreased the free fatty acid hepatic lipid content (liver index, TC, TG, and free fatty acid); inhibited oxidative stress and lipid peroxidation; extenuated hepatic steatosis; and inhibited ER stress and inflammasome activation in high-fat diet-fed golden hamsters. In addition, for the first time, the potential mechanism by which THP protects against HLP through the TLR4-NF-κB signaling pathway was demonstrated. In conclusion, these data indicate that THP attenuates HLP through a variety of effects, including antioxidative stress, anti-ER stress, and anti-inflammatory effects. In addition, THP also inhibited the TLR4-NF-κB signaling pathway in golden hamsters.




2017 ◽  
Vol 59 (1) ◽  
pp. 81-92 ◽  
Author(s):  
Long The Nguyen ◽  
Sonia Saad ◽  
Yi Tan ◽  
Carol Pollock ◽  
Hui Chen

Maternal obesity has been shown to increase the risk of obesity and related disorders in the offspring, which has been partially attributed to changes of appetite regulators in the offspring hypothalamus. On the other hand, endoplasmic reticulum (ER) stress and autophagy have been implicated in hypothalamic neuropeptide dysregulation, thus may also play important roles in such transgenerational effect. In this study, we show that offspring born to high-fat diet-fed dams showed significantly increased body weight and glucose intolerance, adiposity and plasma triglyceride level at weaning. Hypothalamic mRNA level of the orexigenic neuropeptide Y (NPY) was increased, while the levels of the anorexigenic pro-opiomelanocortin (POMC), NPY1 receptor (NPY1R) and melanocortin-4 receptor (MC4R) were significantly downregulated. In association, the expression of unfolded protein response (UPR) markers including glucose-regulated protein (GRP)94 and endoplasmic reticulum DNA J domain-containing protein (Erdj)4 was reduced. By contrast, protein levels of autophagy-related genes Atg5 and Atg7, as well as mitophagy marker Parkin, were slightly increased. The administration of 4-phenyl butyrate (PBA), a chemical chaperone of protein folding and UPR activator, in the offspring from postnatal day 4 significantly reduced their body weight, fat deposition, which were in association with increased activating transcription factor (ATF)4, immunoglobulin-binding protein (BiP) and Erdj4 mRNA as well as reduced Parkin, PTEN-induced putative kinase (PINK)1 and dynamin-related protein (Drp)1 protein expression levels. These results suggest that hypothalamic ER stress and mitophagy are among the regulatory factors of offspring metabolic changes due to maternal obesity.



2012 ◽  
Vol 302 (6) ◽  
pp. E654-E665 ◽  
Author(s):  
Banumathi K. Cole ◽  
Norine S. Kuhn ◽  
Shamina M. Green-Mitchell ◽  
Kendall A. Leone ◽  
Rebekah M. Raab ◽  
...  

Central obesity is associated with chronic inflammation, insulin resistance, β-cell dysfunction, and endoplasmic reticulum (ER) stress. The 12/15-lipoxygenase enzyme (12/15-LO) promotes inflammation and insulin resistance in adipose and peripheral tissues. Given that obesity is associated with ER stress and 12/15-LO is expressed in adipose tissue, we determined whether 12/15-LO could mediate ER stress signals. Addition of 12/15-LO lipid products 12(S)-HETE and 12(S)-HPETE to differentiated 3T3-L1 adipocytes induced expression and activation of ER stress markers, including BiP, XBP-1, p-PERK, and p-IRE1α. The ER stress inducer, tunicamycin, upregulated ER stress markers in adipocytes with concomitant 12/15-LO activation. Addition of a 12/15-LO inhibitor, CDC, to tunicamycin-treated adipocytes attenuated the ER stress response. Furthermore, 12/15-LO-deficient adipocytes exhibited significantly decreased tunicamycin-induced ER stress. 12/15-LO action involves upregulation of interleukin-12 (IL-12) expression. Tunicamycin significantly upregulated IL-12p40 expression in adipocytes, and IL-12 addition increased ER stress gene expression; conversely, LSF, an IL-12 signaling inhibitor, and an IL-12p40-neutralizing antibody attenuated tunicamycin-induced ER stress. Isolated adipocytes and liver from 12/15-LO-deficient mice fed a high-fat diet revealed a decrease in spliced XBP-1 expression compared with wild-type C57BL/6 mice on a high-fat diet. Furthermore, pancreatic islets from 12/15-LO-deficient mice showed reduced high-fat diet-induced ER stress genes compared with wild-type mice. These data suggest that 12/15-LO activity participates in ER stress in adipocytes, pancreatic islets, and liver. Therefore, reduction of 12/15-LO activity or expression could provide a new therapeutic target to reduce ER stress and downstream inflammation linked to obesity.



Endocrinology ◽  
2016 ◽  
Vol 157 (7) ◽  
pp. 2621-2635 ◽  
Author(s):  
Seong Hee Ahn ◽  
Sook-Young Park ◽  
Ji-Eun Baek ◽  
Su-Youn Lee ◽  
Wook-Young Baek ◽  
...  

Free fatty acid receptor 4 (FFA4) has been reported to be a receptor for n-3 fatty acids (FAs). Although n-3 FAs are beneficial for bone health, a role of FFA4 in bone metabolism has been rarely investigated. We noted that FFA4 was more abundantly expressed in both mature osteoclasts and osteoblasts than their respective precursors and that it was activated by docosahexaenoic acid. FFA4 knockout (Ffar4−/−) and wild-type mice exhibited similar bone masses when fed a normal diet. Because fat-1 transgenic (fat-1Tg+) mice endogenously converting n-6 to n-3 FAs contain high n-3 FA levels, we crossed Ffar4−/− and fat-1Tg+ mice over two generations to generate four genotypes of mice littermates: Ffar4+/+;fat-1Tg−, Ffar4+/+;fat-1Tg+, Ffar4−/−;fat-1Tg−, and Ffar4−/−;fat-1Tg+. Female and male littermates were included in ovariectomy- and high-fat diet-induced bone loss models, respectively. Female fat-1Tg+ mice decreased bone loss after ovariectomy both by promoting osteoblastic bone formation and inhibiting osteoclastic bone resorption than their wild-type littermates, only when they had the Ffar4+/+ background, but not the Ffar4−/− background. In a high-fat diet-fed model, male fat-1Tg+ mice had higher bone mass resulting from stimulated bone formation and reduced bone resorption than their wild-type littermates, only when they had the Ffar4+/+ background, but not the Ffar4−/− background. In vitro studies supported the role of FFA4 as n-3 FA receptor in bone metabolism. In conclusion, FFA4 is a dual-acting factor that increases osteoblastic bone formation and decreases osteoclastic bone resorption, suggesting that it may be an ideal target for modulating metabolic bone diseases.



2014 ◽  
Vol 307 (3) ◽  
pp. R332-R339 ◽  
Author(s):  
Jieyun Yin ◽  
Jian Kuang ◽  
Manisha Chandalia ◽  
Demidmaa Tuvdendorj ◽  
Batbayar Tumurbaatar ◽  
...  

The aim of this study was to investigate effects and mechanisms of electroacupuncture (EA) on blood glucose and insulin sensitivity in mice fed a high-fat diet. Both wild-type (WT) and adipose ectonucleotide pyrophosphate phosphodiesterase (ENPP1) transgenic (TG) mice were fed a high-fat diet for 12 wk; for each mouse, an intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT) were performed with or without EA at abdomen or auricular areas. A high-fat diet-induced insulin resistance in both WT and TG mice. In the WT mice, EA at 3 Hz and 15 Hz, but not at 1 Hz or 100 Hz, via CV4+CV12 significantly reduced postprandial glucose levels; EA at 3 Hz was most potent. The glucose level was reduced by 61.7% at 60 min and 74.5% at 120 min with EA at 3 Hz (all P < 0.001 vs. control). Similar hypoglycemic effect was noted in the TG mice. On the contrary, EA at auricular points increased postprandial glucose level ( P < 0.03). 4). EA at 3 Hz via CV4+CV12 significantly enhanced the decrease of blood glucose after insulin injection, suggesting improvement of insulin sensitivity. Plasma free fatty acid was significantly suppressed by 42.5% at 15 min and 50.8% at 30 min with EA ( P < 0.01) in both WT and TG mice. EA improves glucose tolerance in both WT and TG mice fed a high-fat diet, and the effect is associated with stimulation parameters and acupoints and is probably attributed to the reduction of free fatty acid.



2020 ◽  
Vol 32 (14) ◽  
pp. 1169
Author(s):  
Arpitha Rao ◽  
Aparna Satheesh ◽  
Guruprasad Nayak ◽  
Pooja Suresh Poojary ◽  
Sandhya Kumari ◽  
...  

The present study was designed to investigate the effect of diet-induced obesity on endoplasmic reticulum (ER) stress in oocytes. Swiss albino mice (3 weeks old) were fed with a high-fat diet (HFD) for 8 weeks. Oocytes were assessed for lipid droplet accumulation, oxidative stress, ER stress and their developmental potential invitro. High lipid accumulation (P&lt;0.01) and elevated intracellular levels of reactive oxygen species were observed in both germinal vesicle and MII oocytes of HFD-fed mice (P&lt;0.05 and P&lt;0.01 respectively compared with control). Further, expression of the ER stress markers X-box binding protein 1 (XBP1), glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4) and activating transcription factor 6 (ATF6) was significantly (P&lt;0.001) higher in oocytes of the HFD than control group. Oocytes from HFD-fed mice exhibited poor fertilisation and blastocyst rates, a decrease in total cell number and high levels of DNA damage (P&lt;0.01) compared with controls. In conclusion, diet-induced obesity resulted in elevated lipid levels and higher oxidative and ER stress in oocytes, which contributed to the compromised developmental potential of embryos.



2021 ◽  
Author(s):  
Xiaojun Ma ◽  
Yujie Guo ◽  
Pengfei Li ◽  
Jingjing Xu ◽  
Shengqi Dong ◽  
...  

Abstract Background: Type 2 diabetes mellitus (T2DM) and Alzheimer’s disease (AD) are two prevalent diseases with comparable pathophysiological features and genetic predisposition. Polyunsaturated fatty acids (PUFAs) are essential in maintaining normal brain function. However, little is known about the impact of dietary n-6/n-3 PUFA ratio on AD-like pathology, especially in high-fat diet (HFD)-fed AD model mice. Methods: In the present study, the APP/PS1 mice were treated with 60% HFD for 3.5 months to induced insulin resistance. After that, 45% HFD with different n-6/n-3 PUFA ratios (n-6/n-3=1:1, 5:1 or 16:1) was applied for additional 3.5 months treatment. Following the dietary intervention, the behavior of mice was observed using the Water maze. Following behavioral testing, the animals were euthanized, and serum and tissue samples were collected for biochemical, histological and pathological analyses and evaluation. Cortical fatty acid profile was measured by gas chromatography. Western Blot and immunohistochemistry methods were used to detect protein expression of molecules related to AD pathology and insulin signaling pathway(s) in the brain sample tissues. Immunofluorescence assay was used to uncover the expression and migration of NF-κB in the cortex. qPCR method was applied to determine the gene expression of cortical pro-inflammatory cytokines.Results: HFD caused insulin resistance, increased serum IL-6 and TNF-α level, elevated cortical soluble Aβ1-40, Aβ1-42 content, and increased brain n-6/n-3 PUFAs ratio in APP/PS1 mice. Increased APP and BACE1 protein expression and p-IR/IR ratio, but decreased pro-inflammatory cytokines mRNA expression was observed in the cortex from 60% HFD-fed APP/PS1 mice. N-3 PUFAs rich diet (n-6/n-3=1:1) relieved insulin resistance and hyperlipidemia induced by 60% HFD. Cortical soluble Aβ1-40 and Aβ1-42 contents, the expression of cortical APP, GLUT3, insulin metabolism related molecules, and NF-κB pathway downstream pro-inflammatory cytokines showed a dietary n-6/n-3 PUFAs ratio-dependent way, indicating that dietary n-6/n-3 PUFA ratio plays a critical role in modifying the responses of serum inflammatory cytokine, AD pathology, cortical n-6/n-3 PUFAs ratio, insulin signaling and neuroinflammation to HFD treatment.Conclusion: Dietary n-6/n-3 PUFA ratio play an important role in modifying AD pathophysiology, insulin signaling pathway, and neuro-inflammation response to high fat diet treatment in brain.



2020 ◽  
Author(s):  
Nadine Suffee ◽  
Elodie Baptista ◽  
Jérôme Piquereau ◽  
Maharajah Ponnaiah ◽  
Nicolas Doisne ◽  
...  

SUMMARYMetabolic disorders such as obesity are risk factors of atrial fibrillation, not only by sharing comorbidities but likely through their direct impact on atria, notably its adipogenicity. Here, we submitted mice that lack cardiac adipose tissue to a high fat diet and first studied the atrial metabolomic and lipidomic phenotypes using liquid chromatography-mass spectrometry. We found an increased consumption of free fatty acid by the beta-oxidation and an accumulation of long-chain lipids in atria of obese mice. Free fatty acid was the main substrate of mitochondrial respiration studied in the saponin-permeabilized atrial muscle. Conducted action potential recorded in atrial trabeculae was short, and ATP-sensitive potassium current was increased in perforated patch-clamp atrial myocytes of obese mice. There was histological and phenotypical evidence for an accumulation of adipose tissue in obese mice atria. Thus, an obesogenic diet transforms the energy metabolism, causes fat accumulation and induces electrical remodeling of atria myocardium.HIGHLIGHTS- Untargeted metabolomic and lipidomic analysis revealed that a high fat diet induces profound transformation of atrial energy metabolism with beta-oxidation activation and long-chain lipid accumulation.- Mitochondria respiration studied in atrial myocardial trabecula preferentially used Palmitoyl-CoA as energy substrate in obese mice.- Atria of obese mice become vulnerable to atrial fibrillation and show short action potential due to the activation of K-ATP dependent potassium current.- Adipocytes and fat molecular markers were detected in atria of obese mice together with an inflammatory profile consistence with a myocardial accumulation of fat.



2018 ◽  
Vol 315 (5) ◽  
pp. E1053-E1061 ◽  
Author(s):  
Anik Boudreau ◽  
Allison J. Richard ◽  
Jasmine A. Burrell ◽  
William T. King ◽  
Ruth Dunn ◽  
...  

An ethanolic extract of Artemisia scoparia (SCO) has metabolically favorable effects on adipocyte development and function in vitro and in vivo. In diet-induced obese mice, SCO supplementation significantly reduced fasting glucose and insulin levels. Given the importance of adipocyte lipolysis in metabolic health, we hypothesized that SCO modulates lipolysis in vitro and in vivo. Free fatty acids and glycerol were measured in the sera of mice fed a high-fat diet with or without SCO supplementation. In cultured 3T3-L1 adipocytes, the effects of SCO on lipolysis were assessed by measuring glycerol and free fatty acid release. Microarray analysis, qPCR, and immunoblotting were used to assess gene expression and protein abundance. We found that SCO supplementation of a high-fat diet in mice substantially reduces circulating glycerol and free fatty acid levels, and we observed a cell-autonomous effect of SCO to significantly attenuate tumor necrosis factor-α (TNFα)-induced lipolysis in cultured adipocytes. Although several prolipolytic and antilipolytic genes were identified by microarray analysis of subcutaneous and visceral adipose tissue from SCO-fed mice, regulation of these genes did not consistently correlate with SCO’s ability to reduce lipolytic metabolites in sera or cell culture media. However, in the presence of TNFα in cultured adipocytes, SCO induced antilipolytic changes in phosphorylation of hormone-sensitive lipase and perilipin. Together, these data suggest that the antilipolytic effects of SCO on adipose tissue play a role in the ability of this botanical extract to improve whole body metabolic parameters and support its use as a dietary supplement to promote metabolic resiliency.





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