34 results on '"Chan, Stanley M H"'
Search Results
2. Apocynin Prevents Cigarette Smoke-Induced Anxiety-Like Behavior and Preserves Microglial Profiles in Male Mice.
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Alateeq, Rana, Akhtar, Alina, De Luca, Simone N., Chan, Stanley M. H., and Vlahos, Ross
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RECOGNITION (Psychology) ,CHRONIC obstructive pulmonary disease ,SMOKING ,NADPH oxidase ,PNEUMONIA ,LUNGS - Abstract
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally and is primarily caused by cigarette smoking (CS). Neurocognitive comorbidities such as anxiety and cognitive impairments are common among people with COPD. CS-induced lung inflammation and oxidative stress may "spill-over" into the systemic circulation, driving the onset of these comorbidities. We investigated whether a prophylactic treatment with the NADPH Oxidase 2 (NOX2) inhibitor, apocynin, could prevent CS-induced neurocognitive impairments. Adult male BALB/c mice were exposed to CS (9 cigarettes/day, 5 days/week) or room air (sham) for 8 weeks with co-administration of apocynin (5 mg/kg, intraperitoneal injection once daily) or vehicle (0.01% DMSO in saline). Following 7 weeks of CS exposure, mice underwent behavioral testing to assess recognition and spatial memory (novel object recognition and Y maze, respectively) and anxiety-like behaviors (open field and elevated plus maze). Mice were then euthanized, and blood, lungs, and brains were collected. Apocynin partially improved CS-induced lung neutrophilia and reversed systemic inflammation (C-reactive protein) and oxidative stress (malondialdehyde). Apocynin exerted an anxiolytic effect in CS-exposed mice, which was associated with restored microglial profiles within the amygdala and hippocampus. Thus, targeting oxidative stress using apocynin can alleviate anxiety-like behaviors and could represent a novel strategy for managing COPD-related anxiety disorders. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Inhibition of oxidative stress by apocynin attenuated chronic obstructive pulmonary disease progression and vascular injury by cigarette smoke exposure
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Chan, Stanley M. H., primary, Brassington, Kurt, additional, Almerdasi, Suleman Abdullah, additional, Dobric, Aleksandar, additional, De Luca, Simone N., additional, Coward‐Smith, Madison, additional, Wang, Hao, additional, Mou, Kevin, additional, Akhtar, Alina, additional, Alateeq, Rana Abdullah, additional, Wang, Wei, additional, Seow, Huei Jiunn, additional, Selemidis, Stavros, additional, Bozinovski, Steven, additional, and Vlahos, Ross, additional
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- 2023
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4. Cigarette Smoke Exposure Induces Neurocognitive Impairments and Neuropathological Changes in the Hippocampus
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Dobric, Aleksandar, primary, De Luca, Simone N., additional, Seow, Huei Jiunn, additional, Wang, Hao, additional, Brassington, Kurt, additional, Chan, Stanley M. H., additional, Mou, Kevin, additional, Erlich, Jonathan, additional, Liong, Stella, additional, Selemidis, Stavros, additional, Spencer, Sarah J., additional, Bozinovski, Steven, additional, and Vlahos, Ross, additional
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- 2022
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5. Angiotensin II Causes β-Cell Dysfunction Through an ER Stress-Induced Proinflammatory Response
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Chan, Stanley M H, Lau, Yeh-Siang, Miller, Alyson A, Ku, Jacqueline M, Potocnik, Simon, Ye, Ji-Ming, Woodman, Owen L, and Herbert, Terence P
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- 2017
6. Influenza A Virus-Driven Airway Inflammation may be Dissociated From Limb Muscle Atrophy in Cigarette Smoke-Exposed Mice
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Mou, Kevin, primary, Chan, Stanley M. H., additional, Brassington, Kurt, additional, Dobric, Aleksandar, additional, De Luca, Simone N., additional, Seow, Huei Jiunn, additional, Selemidis, Stavros, additional, Bozinovski, Steven, additional, and Vlahos, Ross, additional
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- 2022
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7. Ebselen Prevents Cigarette Smoke-Induced Cognitive Dysfunction In Mice By Preserving Hippocampal Synaptophysin Expression
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De Luca, Simone N., primary, Brassington, Kurt, additional, Chan, Stanley M. H., additional, Dobric, Aleksandar, additional, Mou, Kevin, additional, Seow, Huei Jiunn, additional, and Vlahos, Ross, additional
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- 2021
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8. Apocynin prevents cigarette smoking‐induced loss of skeletal muscle mass and function in mice by preserving proteostatic signalling
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Chan, Stanley M. H., primary, Bernardo, Ivan, additional, Mastronardo, Chanelle, additional, Mou, Kevin, additional, De Luca, Simone N., additional, Seow, Huei Jiunn, additional, Dobric, Aleksandar, additional, Brassington, Kurt, additional, Selemidis, Stavros, additional, Bozinovski, Steven, additional, and Vlahos, Ross, additional
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- 2021
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9. Ebselen reduces cigarette smoke‐induced endothelial dysfunction in mice
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Brassington, Kurt, primary, Chan, Stanley M. H., additional, Seow, Huei Jiunn, additional, Dobric, Aleksandar, additional, Bozinovski, Steven, additional, Selemidis, Stavros, additional, and Vlahos, Ross, additional
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- 2021
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10. Ebselen abolishes vascular dysfunction in influenza A virus-induced exacerbations of cigarette smoke-induced lung inflammation in mice.
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Brassington, Kurt, Chan, Stanley M. H., De Luca, Simone N., Dobric, Aleksandar, Almerdasi, Suleman A., Mou, Kevin, Huei Jiunn Seow, Oseghale, Osezua, Bozinovski, Steven, Selemidis, Stavros, and Vlahos, Ross
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PNEUMONIA , *EBSELEN , *NITRIC-oxide synthases , *CHRONIC obstructive pulmonary disease , *THORACIC aorta - Abstract
People with chronic obstructive pulmonary disease (COPD) are susceptible to respiratory infections which exacerbate pulmonary and/or cardiovascular complications, increasing their likelihood of death. The mechanisms driving these complications remain unknown but increased oxidative stress has been implicated. Here we investigated whether influenza A virus (IAV) infection, following chronic cigarette smoke (CS) exposure, worsens vascular function and if so, whether the antioxidant ebselen alleviates this vascular dysfunction. Male BALB/c mice were exposed to either room air or CS for 8 weeks followed by inoculation with IAV (Mem71, 1 × 104.5 pfu). Mice were treated with ebselen (10 mg/kg) or vehicle (5% w/v CM-cellulose in water) daily. Mice were culled 3- and 10-days post-infection, and their lungs lavaged to assess inflammation. The thoracic aorta was excised to investigate endothelial and smooth muscle dilator responses, expression of key vasodilatory and oxidative stress modulators, infiltrating immune cells and vascular remodelling. CS increased lung inflammation and caused significant vascular endothelial dysfunction, which was worsened by IAV infection. CS-driven increases in vascular oxidative stress, aortic wall remodelling and suppression of endothelial nitric oxide synthase (eNOS) were not affected by IAV infection. CS and IAV infection significantly enhanced T cell recruitment into the aortic wall. Ebselen abolished the exaggerated lung inflammation, vascular dysfunction and increased T cell infiltration in CS and IAV-infected mice. Our findings showed that ebselen treatment abolished vascular dysfunction in IAV-induced exacerbations of CS-induced lung inflammation indicating it may have potential for the treatment of cardiovascular comorbidities seen in acute exacerbations of COPD (AECOPD). [ABSTRACT FROM AUTHOR]
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- 2022
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11. Cigarette Smoking Exacerbates Skeletal Muscle Injury without Compromising Its Regenerative Capacity
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Chan, Stanley M. H., primary, Cerni, Claudia, additional, Passey, Samantha, additional, Seow, Huei Jiunn, additional, Bernardo, Ivan, additional, van der Poel, Chris, additional, Dobric, Aleksandar, additional, Brassington, Kurt, additional, Selemidis, Stavros, additional, Bozinovski, Steven, additional, and Vlahos, Ross, additional
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- 2020
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12. Exposure to cigarette smoke precipitates simple hepatosteatosis to NASH in high-fat diet fed mice by inducing oxidative stress.
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Fouda, Sherouk, Khan, Anwar, Chan, Stanley M. H., Mahzari, Ali, Xiu Zhou, Cheng Xue Qin, Vlahos, Ross, and Ji-Ming Ye
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FATTY liver ,HIGH-fat diet ,OXIDATIVE stress ,CIGARETTE smoke ,SMOKING ,NON-alcoholic fatty liver disease - Abstract
Consumption of diet rich in fat and cigarette smoking (CS) are independent risk factors of non-alcoholic steatohepatitis (NASH), and they often occur together in some populations. The present study investigated the mechanisms of high-fat diet (HFD) and CS, individually and in combination, on the pathogenesis of NASH in mice. C57BL/6 male mice were subjected to either a low-fat chow (CH) or HFD with or without mainstream CS-exposure (4 cigarettes/day, 5 days/week for 14 weeks). HFD alone caused hepatosteatosis (2.5-fold increase in TG content) and a significant increase in 3-nitrotyrisine (by ~40-fold) but without an indication of liver injury, inflammation or fibrosis. CS alone in CH-fed mice increased in Tnfa expression and macrophage infiltration by 2-fold and relatively less increase in 3-nitrotyrosine (18-fold). Combination of HFD and CS precipitated hepatosteatosis to NASH reflected by exacerbated makers of liver inflammation and fibrosis which were associated with much severe liver oxidative stress (90-fold increase in 3-nitrotyrisine along with 6-fold increase in carbonylated proteins and 56% increase in lipid oxidations). Further studies were performed to administer the antioxidant tempol to CS exposed HFD mice and the results showed that the inhibition of liver oxidative stress prevented inflammatory and fibrotic changes in liver despite persisting hepatosteatosis. Our findings suggest that oxidative stress is a key mechanism underlying CS-promoted progression of simple hepatosteatosis to NASH. Targeting hepatic oxidative stress may be a viable strategy in halting the progression of metabolic associated fatty liver disease. [ABSTRACT FROM AUTHOR]
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- 2021
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13. Ebselen prevents cigarette smoke-induced gastrointestinal dysfunction in mice.
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Balasuriya, Gayathri K., Mohsenipour, Mitra, Brassington, Kurt, Dobric, Aleksandar, De Luca, Simone N., Kevin Mou, Huei Jiunn Seow, Chalystha Yie Qin Lee, Herath, Madushani, Chan, Stanley M. H., Vlahos, Ross, and Hill-Yardin, Elisa L.
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OBSTRUCTIVE lung diseases ,SMOKING ,CIGARETTES ,PNEUMONIA ,MICE ,EBSELEN - Abstract
Gastrointestinal (GI) dysfunction is a common comorbidity of chronic obstructive pulmonary disease (COPD) for which a major cause is cigarette smoking (CS). The underlying mechanisms and precise effects of CS on gut contractility, however, are not fully characterised. Therefore, the aim of the present study was to investigate whether CS impacts GI function and structure in a mouse model of CS-induced COPD. We also aimed to investigate GI function in the presence of ebselen, an antioxidant that has shown beneficial effects on lung inflammation resulting from CS exposure. Mice were exposed to CS for 2 or 6 months. GI structure was analysed by histology and immunofluorescence. After 2 months of CS exposure, ex vivo gut motility was analysed using video-imaging techniques to examine changes in colonic migrating motor complexes (CMMCs). CS decreased colon length in mice. Mice exposed to CS for 2 months had a higher frequency of CMMCs and a reduced resting colonic diameter but no change in enteric neuron numbers. Ten days cessation after 2 months CS reversed CMMC frequency changes but not the reduced colonic diameter phenotype. Ebselen treatment reversed the CS-induced reduction in colonic diameter. After 6 months CS, the number of myenteric nitric-oxide producing neurons was significantly reduced. This is the first evidence of colonic dysmotility in a mouse model of CS-induced COPD. Dysmotility after 2 months CS is not due to altered neuron numbers; however, prolonged CS-exposure significantly reduced enteric neuron numbers in mice. Further research is needed to assess potential therapeutic applications of ebselen in GI dysfunction in COPD. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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14. Cigarette smoking blocks the benefit from reduced weight gain for insulin action by shifting lipids deposition to muscle.
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Khan, Anwar, Fouda, Sherouk, Mahzari, Ali, Chan, Stanley M. H., Xiu Zhou, Ratnam, Cherubina, Vlahos, Ross, and Ji-Ming Ye
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WEIGHT gain ,SMOKING ,INSULIN ,LIPIDS ,BODY weight ,ADIPOSE tissue transplantation - Abstract
Cigarette smoking (CS) is known to reduce body weight and this often masks its real effect on insulin action. The present study tested the hypothesis that CS can divert lipid deposition to muscles to offset the supposed benefit of reduced body weight gain on insulin signalling in this major site for glucose tolerance (or insulin action). The study was conducted in mice exposed to chronic CS followed by either a chow (CH) diet or a high-fat (HF) diet. CS increased triglyceride (TG) levels in both plasma and muscle despite a reduced body weight gain and adiposity. CS led to glucose intolerance in CH-fed mice and they retained the glucose intolerance that was induced by the HF diet. In adipose tissue, CS increased macrophage infiltration and the mRNA expression of TNFa but suppressed the protein expression of adipose triglyceride lipase and PPAR?. While CS increased hormone-sensitive lipase and suppressed the mRNA expression of leptin, these effects were blunted in HF-fed mice. These results imply that CS impairs insulin signalling in skeletal muscle via accumulated intramuscular lipids from lipolysis and lipodystrophy of adipose tissues. This may explain why smokers may not benefit from insulin sensitising effects of reduced body weight gain. [ABSTRACT FROM AUTHOR]
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- 2020
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15. 3′,4′-dihydroxyflavonol ameliorates endoplasmic reticulum stress-induced apoptosis and endothelial dysfunction in mice
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Lau, Yeh Siang, primary, Mustafa, Mohd Rais, additional, Choy, Ker Woon, additional, Chan, Stanley M. H., additional, Potocnik, Simon, additional, Herbert, Terence P., additional, and Woodman, Owen L., additional
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- 2018
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16. System-L amino acid transporters play a key role in pancreatic β-cell signalling and function
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Cheng, Qi, primary, Beltran, Violeta D, additional, Chan, Stanley M H, additional, Brown, Jeremy R, additional, Bevington, Alan, additional, and Herbert, Terence P, additional
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- 2016
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17. Endoplasmic reticulum stress up‐regulates Nedd4‐2 to induce autophagy
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Wang, Hao, primary, Sun, Ruo‐Qiong, additional, Camera, Daria, additional, Zeng, Xiao‐Yi, additional, Jo, Eunjung, additional, Chan, Stanley M. H., additional, Herbert, Terence P., additional, Molero, Juan C., additional, and Ye, Ji‐Ming, additional
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- 2016
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18. Neonatal overfeeding attenuates acute central pro-inflammatory effects of short-term high fat diet
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Cai, Guohui, primary, Dinan, Tara, additional, Barwood, Joanne M., additional, De Luca, Simone N., additional, Soch, Alita, additional, Ziko, Ilvana, additional, Chan, Stanley M. H., additional, Zeng, Xiao-Yi, additional, Li, Songpei, additional, Molero, Juan, additional, and Spencer, Sarah J., additional
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- 2015
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19. Endoplasmic reticulum stress up-regulates Nedd4-2 to induce autophagy.
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Hao Wang, Ruo-Qiong Sun, Camera, Daria, Xiao-Yi Zeng, Eunjung Jo, Chan, Stanley M. H., Herbert, Terence P., Molero, Juan C., and Ji-Ming Ye
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- 2016
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20. Differing Endoplasmic Reticulum Stress Response to Excess Lipogenesis versus Lipid Oversupply in Relation to Hepatic Steatosis and Insulin Resistance
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Ren, Lu-Ping, primary, Chan, Stanley M. H., additional, Zeng, Xiao-Yi, additional, Laybutt, D. Ross, additional, Iseli, Tristan J., additional, Sun, Ruo-Qiong, additional, Kraegen, Edward W., additional, Cooney, Gregory J., additional, Turner, Nigel, additional, and Ye, Ji-Ming, additional
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- 2012
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21. Neonatal overfeeding attenuates acute central pro-inflammatory effects of short-term high fat diet.
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Guohui Cai, Dinan, Tara, Barwood, Joanne M., De Luca, Simone N., Soch, Alita, Ziko, Ilvana, Chan, Stanley M. H., Xiao-Yi Zeng, Songpei Li, Molero, Juan, and Spencer, Sarah J.
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NEONATAL infections ,IMMUNOLOGY of inflammation ,MICROGLIA ,CHILDHOOD obesity ,PARAVENTRICULAR nucleus - Abstract
Neonatal obesity predisposes individuals to obesity throughout life. In rats, neonatal overfeeding also leads to early accelerated weight gain that persists into adulthood. The phenotype is associated with dysfunction in a number of systems including paraventricular nucleus of the hypothalamus (PVN) responses to psychological and immune stressors. However, in many cases weight gain in neonatally overfed rats stabilizes in early adulthood so the animal does not become more obese as it ages. Here we examined if neonatal overfeeding by suckling rats in small litters predisposes them to exacerbated metabolic and central inflammatory disturbances if they are also given a high fat diet in later life. In adulthood we gave the rats normal chow, 3 days, or 3 weeks high fat diet (45% kcal from fat) and measured peripheral indices of metabolic disturbance. We also investigated hypothalamic microglial changes, as an index of central inflammation, as well as PVN responses to lipopolysaccharide (LPS). Surprisingly, neonatal overfeeding did not predispose rats to the metabolic effects of a high fat diet. Weight changes and glucose metabolism were unaffected by the early life experience. However, short term (3 day) high fat diet was associated with more microglia in the hypothalamus and a markedly exacerbated PVN response to LPS in control rats; effects not seen in the neonatally overfed. Our findings indicate neonatally overfed animals are not more susceptible to the adverse metabolic effects of a short-term high fat diet but may be less able to respond to the central effects. [ABSTRACT FROM AUTHOR]
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- 2015
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22. Activation of PPARα ameliorates hepatic insulin resistance and steatosis in high fructose-fed mice despite increased endoplasmic reticulum stress.
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Chan, Stanley M H, Sun, Ruo-Qiong, Zeng, Xiao-Yi, Choong, Zi-Heng, Wang, Hao, Watt, Matthew J, and Ye, Ji-Ming
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PROTEIN metabolism , *FENOFIBRATE , *ANIMAL experimentation , *FATTY acids , *FATTY liver , *FRUCTOSE , *INSULIN resistance , *LIVER , *MICE , *THERAPEUTICS - Abstract
Endoplasmic reticulum (ER) stress is suggested to cause hepatic insulin resistance by increasing de novo lipogenesis (DNL) and directly interfering with insulin signaling through the activation of the c-Jun N-terminal kinase (JNK) and IκB kinase (IKK) pathway. The current study interrogated these two proposed mechanisms in a mouse model of hepatic insulin resistance induced by a high fructose (HFru) diet with the treatment of fenofibrate (FB) 100 mg/kg/day, a peroxisome proliferator-activated receptor α (PPARα) agonist known to reduce lipid accumulation while maintaining elevated DNL in the liver. FB administration completely corrected HFru-induced glucose intolerance, hepatic steatosis, and the impaired hepatic insulin signaling (pAkt and pGSK3β). Of note, both the IRE1/XBP1 and PERK/eIF2α arms of unfolded protein response (UPR) signaling were activated. While retaining the elevated DNL (indicated by the upregulation of SREBP1c, ACC, FAS, and SCD1 and [3H]H2O incorporation into lipids), FB treatment markedly increased fatty acid oxidation (indicated by induction of ACOX1, p-ACC, β-HAD activity, and [14C]palmitate oxidation) and eliminated the accumulation of diacylglycerols (DAGs), which is known to have an impact on insulin signaling. Despite the marked activation of UPR signaling, neither JNK nor IKK appeared to be activated. These findings suggest that lipid accumulation (mainly DAGs), rather than the activation of JNK or IKK, is pivotal for ER stress to cause hepatic insulin resistance. Therefore, by reducing the accumulation of deleterious lipids, activation of PPARα can ameliorate hepatic insulin resistance against increased ER stress. [ABSTRACT FROM AUTHOR]
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- 2013
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23. Strategies for the discovery and development of anti-diabetic drugs from the natural products of traditional medicines.
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Ye, Ji-Ming, Stanley, M H, and Chan, Stanley M H
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- 2013
24. Strategies for the Discovery and Development of Anti-Diabetic Drugs from the Natural Products of Traditional Medicines.
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Chan, Stanley M. H. and Ji-Ming Ye
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- 2013
25. Differing Endoplasmic Reticulum Stress Response to Excess Lipogenesis versus Lipid Oversupply in Relation to Hepatic Steatosis and Insulin Resistance.
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Lu-Ping Ren, Chan, Stanley M. H., Xiao-Yi Zeng, Laybutt, D. Ross, Iseli, Tristan J., Ruo-Qiong Sun, Kraegen, Edward W., Cooney, Gregory J., Turner, Nigel, and Ji-Ming Ye
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FATTY degeneration , *HYPOGLYCEMIC agents , *PANCREATIC secretions , *INSULIN antibodies , *DRUG resistance , *INSULIN resistance - Abstract
Mitochondrial dysfunction and endoplasmic reticulum (ER) stress have been implicated in hepatic steatosis and insulin resistance. The present study investigated their roles in the development of hepatic steatosis and insulin resistance during de novo lipogenesis (DNL) compared to extrahepatic lipid oversupply. Male C57BL/6J mice were fed either a high fructose (HFru) or high fat (HFat) diet to induce DNL or lipid oversupply in/to the liver. Both HFru and HFat feeding increased hepatic triglyceride within 3 days (by 3.5 and 2.4 fold) and the steatosis remained persistent from 1 week onwards (p<0.01 vs Con). Glucose intolerance (iAUC increased by ∼60%) and blunted insulin-stimulated hepatic Akt and GSK3b phosphorylation (∼40-60%) were found in both feeding conditions (p<0.01 vs Con, assessed after 1 week). No impairment of mitochondrial function was found (oxidation capacity, expression of PGC1α, CPT1, respiratory complexes, enzymatic activity of citrate synthase & β-HAD). As expected, DNL was increased (∼60%) in HFru-fed mice and decreased (32%) in HFat-fed mice (all p<0.05). Interestingly, associated with the upregulated lipogenic enzymes (ACC, FAS and SCD1), two (PERK/eIF2α and IRE1/ XBP1) of three ER stress pathways were significantly activated in HFru-fed mice. However, no significant ER stress was observed in HFat-fed mice during the development of hepatic steatosis. Our findings indicate that HFru and HFat diets can result in hepatic steatosis and insulin resistance without obvious mitochondrial defects via different lipid metabolic pathways. The fact that ER stress is apparent only with HFru feeding suggests that ER stress is involved in DNL per se rather than resulting from hepatic steatosis or insulin resistance. [ABSTRACT FROM AUTHOR]
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- 2012
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26. System-L amino acid transporters play a key role in pancreatic β-cell signalling and function.
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Qi Cheng, Beltran, Violeta D., Chan, Stanley M. H., Brown, Jeremy R., Bevington, Alan, and Herbert, Terence P.
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PANCREATIC beta cells , *AMINO acid transport , *CELLULAR signal transduction , *MTOR protein , *SMALL interfering RNA - Abstract
The branched-chain amino acids (BCAA) leucine, isoleucine and valine, are essential amino acids that play a critical role in cellular signalling and metabolism. They acutely stimulate insulin secretion and activate the regulatory serine/threonine kinase mammalian target of rapamycin complex 1 (mTORC1), a kinase that promotes increased β-cell mass and function. The effects of BCAA on cellular function are dependent on their active transport into the mammalian cells via amino acid transporters and thus the expression and activity of these transporters likely influence β-cell signalling and function. In this report, we show that the System-L transporters are required for BCAA uptake into clonal β-cell lines and pancreatic islets, and that these are essential for signalling to mTORC1. Further investigation revealed that the System-L amino acid transporter 1 (LAT1) is abundantly expressed in the islets, and that knockdown of LAT1 using siRNA inhibits mTORC1 signalling, leucine-stimulated insulin secretion and islet cell proliferation. In summary, we show that the LAT1 is required for regulating β-cell signalling and function in islets and thus may be a novel pharmacological/nutritional target for the treatment and prevention of type 2 diabetes. [ABSTRACT FROM AUTHOR]
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- 2016
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27. Musculoskeletal crosstalk in chronic obstructive pulmonary disease and comorbidities: Emerging roles and therapeutic potentials.
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Mou K, Chan SMH, and Vlahos R
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- Humans, Quality of Life, Comorbidity, Lung, Pulmonary Disease, Chronic Obstructive epidemiology, Musculoskeletal Diseases epidemiology, Musculoskeletal Diseases therapy
- Abstract
Chronic Obstructive Pulmonary Disease (COPD) is a multifaceted respiratory disorder characterized by progressive airflow limitation and systemic implications. It has become increasingly apparent that COPD exerts its influence far beyond the respiratory system, extending its impact to various organ systems. Among these, the musculoskeletal system emerges as a central player in both the pathogenesis and management of COPD and its associated comorbidities. Muscle dysfunction and osteoporosis are prevalent musculoskeletal disorders in COPD patients, leading to a substantial decline in exercise capacity and overall health. These manifestations are influenced by systemic inflammation, oxidative stress, and hormonal imbalances, all hallmarks of COPD. Recent research has uncovered an intricate interplay between COPD and musculoskeletal comorbidities, suggesting that muscle and bone tissues may cross-communicate through the release of signalling molecules, known as "myokines" and "osteokines". We explored this dynamic relationship, with a particular focus on the role of the immune system in mediating the cross-communication between muscle and bone in COPD. Moreover, we delved into existing and emerging therapeutic strategies for managing musculoskeletal disorders in COPD. It underscores the development of personalized treatment approaches that target both the respiratory and musculoskeletal aspects of COPD, offering the promise of improved well-being and quality of life for individuals grappling with this complex condition. This comprehensive review underscores the significance of recognizing the profound impact of COPD on the musculoskeletal system and its comorbidities. By unravelling the intricate connections between these systems and exploring innovative treatment avenues, we can aspire to enhance the overall care and outcomes for COPD patients, ultimately offering hope for improved health and well-being., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2024
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28. Cigarette smoke-induced pulmonary impairment is associated with social recognition memory impairments and alterations in microglial profiles within the suprachiasmatic nucleus of the hypothalamus.
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De Luca SN, Chan SMH, Dobric A, Wang H, Seow HJ, Brassington K, Mou K, Alateeq R, Akhtar A, Bozinovski S, and Vlahos R
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- Humans, Adult, Male, Mice, Animals, Microglia, Dimethyl Sulfoxide pharmacology, Quality of Life, Lung, Suprachiasmatic Nucleus, Hypothalamus, Inflammation complications, Mice, Inbred C57BL, Cigarette Smoking adverse effects, Pulmonary Disease, Chronic Obstructive, Pneumonia complications
- Abstract
Chronic obstructive pulmonary disease (COPD) is a major, incurable respiratory condition that is primarily caused by cigarette smoking (CS). Neurocognitive disorders including cognitive dysfunction, anxiety and depression are highly prevalent in people with COPD. It is understood that increased lung inflammation and oxidative stress from CS exposure may 'spill over' into the systemic circulation to promote the onset of these extra-pulmonary comorbidities, and thus impacts the quality of life of people with COPD. The precise role of the 'spill-over' of inflammation and oxidative stress in the onset of COPD-related neurocognitive disorders are unclear. The present study investigated the impact of chronic CS exposure on anxiety-like behaviors and social recognition memory, with a particular focus on the role of the 'spill-over' of inflammation and oxidative stress from the lungs. Adult male BALB/c mice were exposed to either room air (sham) or CS (9 cigarettes per day, 5 days a week) for 24 weeks and were either daily co-administered with the NOX2 inhibitor, apocynin (5 mg/kg, in 0.01 % DMSO diluted in saline, i.p.) or vehicle (0.01 % DMSO in saline) one hour before the initial CS exposure of the day. After 23 weeks, mice underwent behavioral testing and physiological diurnal rhythms were assessed by monitoring diurnal regulation profiles. Lungs were collected and assessed for hallmark features of COPD. Consistent with its anti-inflammatory and oxidative stress properties, apocynin treatment partially lessened lung inflammation and lung function decline in CS mice. CS-exposed mice displayed marked anxiety-like behavior and impairments in social recognition memory compared to sham mice, which was prevented by apocynin treatment. Apocynin was unable to restore the decreased Bmal1-positive cells, key in cells in diurnal regulation, in the suprachiasmatic nucleus of the hypothalamus to that of sham levels. CS-exposed mice treated with apocynin was associated with a restoration of microglial area per cell and basal serum corticosterone. This data suggests that we were able to model the CS-induced social recognition memory impairments seen in humans with COPD. The preventative effects of apocynin on memory impairments may be via a microglial dependent mechanism., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2023
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29. Pathobiological mechanisms underlying metabolic syndrome (MetS) in chronic obstructive pulmonary disease (COPD): clinical significance and therapeutic strategies.
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Chan SMH, Selemidis S, Bozinovski S, and Vlahos R
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- Animals, Comorbidity, Humans, Metabolic Syndrome drug therapy, Metabolic Syndrome immunology, Metabolic Syndrome metabolism, Pulmonary Disease, Chronic Obstructive drug therapy, Pulmonary Disease, Chronic Obstructive immunology, Pulmonary Disease, Chronic Obstructive metabolism, Metabolic Syndrome epidemiology, Pulmonary Disease, Chronic Obstructive epidemiology
- Abstract
Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and is currently the 4th largest cause of death in the world. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities (e.g. skeletal muscle wasting, ischemic heart disease, cognitive dysfunction) and infective viral and bacterial acute exacerbations (AECOPD). Current pharmacological treatments for COPD are relatively ineffective and the development of effective therapies has been severely hampered by the lack of understanding of the mechanisms and mediators underlying COPD. Since comorbidities have a tremendous impact on the prognosis and severity of COPD, the 2015 American Thoracic Society/European Respiratory Society (ATS/ERS) Research Statement on COPD urgently called for studies to elucidate the pathobiological mechanisms linking COPD to its comorbidities. It is now emerging that up to 50% of COPD patients have metabolic syndrome (MetS) as a comorbidity. It is currently not clear whether metabolic syndrome is an independent co-existing condition or a direct consequence of the progressive lung pathology in COPD patients. As MetS has important clinical implications on COPD outcomes, identification of disease mechanisms linking COPD to MetS is the key to effective therapy. In this comprehensive review, we discuss the potential mechanisms linking MetS to COPD and hence plausible therapeutic strategies to treat this debilitating comorbidity of COPD., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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30. The inositol-requiring enzyme 1 (IRE1α) RNAse inhibitor, 4µ8C, is also a potent cellular antioxidant.
- Author
-
Chan SMH, Lowe MP, Bernard A, Miller AA, and Herbert TP
- Subjects
- Animals, Cells, Cultured, Endoplasmic Reticulum drug effects, Endoplasmic Reticulum metabolism, Endoplasmic Reticulum Stress drug effects, Hymecromone pharmacology, Mice, Reactive Oxygen Species metabolism, Ribonucleases antagonists & inhibitors, Unfolded Protein Response drug effects, Antioxidants pharmacology, Endoribonucleases antagonists & inhibitors, Hymecromone analogs & derivatives, Protein Serine-Threonine Kinases antagonists & inhibitors
- Abstract
Inositol-requiring enzyme 1 alpha (IRE1α) is an endoplasmic reticulum (ER)-transmembrane endonuclease that is activated in response to ER stress as part of the unfolded protein response (UPR). Chronic activation of the UPR has been implicated in the pathogenesis of many common diseases including diabetes, cancer, and neurological pathologies such as Huntington's and Alzheimer's disease. 7-Hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde (4µ8C) is widely used as a specific inhibitor of IRE1α ribonuclease activity (IC
50 of 6.89 µM in cultured cells). However, in this paper, we demonstrate that 4µ8C acts as a potent reactive oxygen species (ROS) scavenger, both in a cell-free assay and in cultured cells, at concentrations lower than that widely used to inhibit IRE1α activity. In vitro we show that, 4µ8C effectively decreases xanthine/xanthine oxidase catalysed superoxide production with an IC50 of 0.2 µM whereas in cultured endothelial and clonal pancreatic β-cells, 4µ8C inhibits angiotensin II-induced ROS production with IC50 values of 1.92 and 0.29 µM, respectively. In light of this discovery, conclusions reached using 4µ8C as an inhibitor of IRE1α should be carefully evaluated. However, this unexpected off-target effect of 4µ8C may prove therapeutically advantageous for the treatment of pathologies that are thought to be caused by, or exacerbated by, both oxidative and ER stress such as endothelial dysfunction and/or diabetes., (© 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)- Published
- 2018
- Full Text
- View/download PDF
31. The role of de novo protein synthesis and SIRT1 in ER stress-induced Atf4 and Chop mRNA expression in mammalian cells.
- Author
-
Chan SMH, Zhao X, Elfowiris A, Ratnam C, and Herbert TP
- Subjects
- Animals, Mice, Phosphorylation, Protein Biosynthesis, Unfolded Protein Response, Up-Regulation, Activating Transcription Factor 4 genetics, Endoplasmic Reticulum Stress, Eukaryotic Initiation Factor-2 metabolism, Signal Transduction, Sirtuin 1, Transcription Factor CHOP genetics
- Abstract
Endoplasmic reticulum (ER) stress and the activation of the unfolded protein response (UPR) have been implicated in the pathogenesis of many common human diseases. Integral to the UPR and an important determinant in cell fate is the expression of the pro-apoptotic transcription factor C/EBP homologous protein (CHOP). This is promoted by activating transcription factor 4 (ATF4) whose expression is rapidly up-regulated in response to ER stress through an eIF2α phosphorylation-dependent increase in protein synthesis. Our data demonstrates that this ER stress-induced increase in ATF4 and CHOP expression is initiated by an increase in Atf4 and Chop mRNA, which is also dependent upon eIF2α phosphorylation. Despite being dependent on eIF2α phosphorylation, we provide evidence that these increases in Atf4 and Chop mRNA expression may occur independently of de novo protein synthesis. Moreover, we show that ER stress-induced Chop mRNA expression is exacerbated by Sirtuin-1 (SIRT1) inhibition indicating that changes in the energy status of the cell may play an important role in its regulation. This work highlights and extends previous findings, and provides important new insights into the mechanism of ER stress-induced expression of Atf4 and Chop mRNA that clearly warrants further investigation., (Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
32. Fenofibrate insulates diacylglycerol in lipid droplet/ER and preserves insulin signaling transduction in the liver of high fat fed mice.
- Author
-
Chan SM, Zeng XY, Sun RQ, Jo E, Zhou X, Wang H, Li S, Xu A, Watt MJ, and Ye JM
- Subjects
- Animals, Diet, High-Fat adverse effects, Endoplasmic Reticulum drug effects, Fatty Liver etiology, Lipid Droplets drug effects, Liver drug effects, Liver metabolism, Liver pathology, Male, Mice, Mice, Inbred C57BL, PPAR alpha metabolism, Signal Transduction, Diglycerides metabolism, Endoplasmic Reticulum metabolism, Fatty Liver metabolism, Fenofibrate pharmacology, Hypolipidemic Agents pharmacology, Insulin metabolism, Lipid Droplets metabolism
- Abstract
Hepatic steatosis is often associated with insulin resistance as a hallmark of the metabolic syndrome in the liver. The present study investigated the effects of PPARα activation induced by fenofibrate (FB) on the relationship of insulin resistance and hepatic steatosis in mice fed a high-fat (HF) diet, which increases lipid influx into the liver. Mice were fed HF diet to induce insulin resistance and hepatic steatosis with or without FB. FB activated PPARα and ameliorated HF diet-induced glucose intolerance and hepatic insulin resistance without altering either hepatic steatosis or inflammation signaling (JNK or IKK). Interestingly, FB treatment simultaneously increased fatty acid (FA) synthesis (50%) and oxidation (66%, both p<0.01) into intermediate lipid metabolites, suggesting a FA oxidation-synthesis cycling in operation. Associated with these effects, diacylglycerols (DAGs) were sequestered within the lipid droplet/ER compartment, thus reducing their deposition in the cellular membrane, which is known to impair insulin signal transduction. These findings suggest that the reduction in membrane DAGs (rather than total hepatic steatosis) may be critical for the protection by fenofibrate-induced PPARα activation against hepatic insulin resistance induced by dietary fat., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
33. IRE1 impairs insulin signaling transduction of fructose-fed mice via JNK independent of excess lipid.
- Author
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Sun RQ, Wang H, Zeng XY, Chan SM, Li SP, Jo E, Leung SL, Molero JC, and Ye JM
- Subjects
- Animals, Insulin Resistance, Male, Membrane Proteins genetics, Mice, Mice, Inbred C57BL, Protein Serine-Threonine Kinases genetics, Unfolded Protein Response, Fructose administration & dosage, Fructose metabolism, Insulin metabolism, JNK Mitogen-Activated Protein Kinases metabolism, Membrane Proteins metabolism, Protein Serine-Threonine Kinases metabolism, Signal Transduction physiology, Triglycerides metabolism
- Abstract
The unfolded protein response (UPR) pathways have been implicated in the development of hepatic insulin resistance during high fructose (HFru) feeding. The present study investigated their roles in initiating impaired insulin signaling transduction in the liver induced by HFru feeding in mice. HFru feeding resulted in hepatic steatosis, increased de novo lipogenesis and activation of two arms of the UPR pathways (IRE1/XBP1 and PERK/eIF2α) in similar patterns from 3days to 8weeks. In order to identify the earliest trigger of impaired insulin signaling in the liver, we fed mice a HFru diet for one day and revealed that only the IRE1 branch was activated (by 2-fold) and insulin-mediated Akt phosphorylation was blunted (~25%) in the liver. There were significant increases in phosphorylation of JNK (~50%) and IRS at serine site (~50%), protein content of ACC and FAS (up to 2.5-fold) and triglyceride level (2-fold) in liver (but not in muscle or fat). Blocking IRE1 activity abolished increases in JNK activity, IRS serine phosphorylation and protected insulin-stimulated Akt phosphorylation without altering hepatic steatosis or PKCε activity, a key link between lipids and insulin resistance. Our findings together suggest that activation of IRE1-JNK pathway is a key linker of impaired hepatic insulin signaling transduction induced by HFru feeding., (Copyright © 2014. Published by Elsevier B.V.)
- Published
- 2015
- Full Text
- View/download PDF
34. Screening for the efficacy on lipid accumulation in 3T3-L1 cells is an effective tool for the identification of new anti-diabetic compounds.
- Author
-
Zeng XY, Zhou X, Xu J, Chan SM, Xue CL, Molero JC, and Ye JM
- Subjects
- 3T3-L1 Cells, Adiposity drug effects, Alkaloids chemistry, Alkaloids pharmacology, Alkaloids therapeutic use, Animals, Anti-Obesity Agents chemistry, Anti-Obesity Agents therapeutic use, Bridged-Ring Compounds chemistry, Bridged-Ring Compounds pharmacology, Bridged-Ring Compounds therapeutic use, Cell Line, Dietary Fats administration & dosage, Drug Evaluation, Preclinical methods, Drugs, Chinese Herbal chemistry, Drugs, Chinese Herbal therapeutic use, Fatty Liver drug therapy, Fatty Liver metabolism, Fructose administration & dosage, Glucose Intolerance drug therapy, Glucose Intolerance metabolism, High-Throughput Screening Assays, Hypoglycemic Agents chemistry, Hypoglycemic Agents therapeutic use, Insulin Resistance, Male, Mice, Mice, Inbred C57BL, Quinolizines chemistry, Quinolizines pharmacology, Quinolizines therapeutic use, Anti-Obesity Agents pharmacology, Drugs, Chinese Herbal pharmacology, Hypoglycemic Agents pharmacology, Lipid Metabolism drug effects, Triglycerides metabolism
- Abstract
Reducing lipid accumulation in insulin target tissues is critical for the treatment of type 2 diabetes. This study aimed to develop a biochemical assay in cells for high throughput (HTP) screening of anti-diabetic drugs by reducing lipid accumulation via different mechanisms. We designed a new method to extract triglyceride (TG) with KOH to allow biochemical quantification of TGs for HTP screening in 3T3-L1 cells. This new method was validated for its biochemical properties with identical results of TG obtained with or without KOH (r(2) = 0.9978, p < 0.001) and a fourfold improvement in TG extraction recovery rate (88-95%, p < 0.001) as compared to the conventional chloroform/methanol extraction (12-18%). The ability of this phenotype screening to capture potential anti-diabetic drugs was verified by pharmacological agents well known to alter lipid accumulation by different mechanisms including AMPK activators, fatty acid synthesis inhibitors, PPARγ activator and several lipogenic substrates. To further demonstrate the application of this screening tool for discovery of new anti-diabetic drugs, we screened >200 new candidates selected from Chinese medicine and identified 49 compounds from different classes which reduced TG content by >50% at 1 μM or >75% at 10 μM. Finally, we tested two selected leads (albiflorin and oxymatrine) in vivo and confirmed their efficacy in reducing visceral adiposity, glucose intolerance and hepatic steatosis in high fat-fed or high fructose-fed mice. Our results indicate that screening for the efficacy on lipid accumulation in cells by biochemical quantification of TGs with KOH extraction is an effective tool for the identification of new anti-diabetic compounds., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
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