scholarly journals Vitamins D and E Stimulate the PI3K-AKT Signalling Pathway in Insulin-Resistant SK-N-SH Neuronal Cells

Nutrients ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2525 ◽  
Author(s):  
Amirah Salwani Zaulkffali ◽  
Nurliyana Najwa Md Razip ◽  
Sharifah Sakinah Syed Alwi ◽  
Afifah Abd Jalil ◽  
Mohd Sokhini Abd Mutalib ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin E ◽  
Glucose Uptake ◽  
Insulin Signalling ◽  
Neuronal Cells ◽  
Signalling Pathway ◽  
Enzyme Linked Immunosorbent Assay ◽  
Expression Levels ◽  
Insulin Resistant ◽  
Insulin Signalling Pathway

This study investigated the effects of vitamins D and E on an insulin-resistant model and hypothesized that this treatment would reverse the effects of Alzheimer’s disease (AD) and improves insulin signalling. An insulin-resistant model was induced in SK-N-SH neuronal cells with a treatment of 250 nM insulin and re-challenged with 100 nM at two different incubation time (16 h and 24 h). The effects of vitamin D (10 and 20 ng/mL), vitamin E in the form of tocotrienol-rich fraction (TRF) (200 ng/mL) and the combination of vitamins D and E on insulin signalling markers (IR, PI3K, GLUT3, GLUT4, and p-AKT), glucose uptake and AD markers (GSK3β and TAU) were determined using quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). The results demonstrated an improvement of the insulin signalling pathway upon treatment with vitamin D alone, with significant increases in IR, PI3K, GLUT3, GLUT4 expression levels, as well as AKT phosphorylation and glucose uptake, while GSK3β and TAU expression levels was decreased significantly. On the contrary, vitamin E alone, increased p-AKT, reduced the ROS as well as GSK3β and TAU but had no effect on the insulin signalling expression levels. The combination of vitamins D and E only showed significant increase in GLUT4, p-AKT, reduced ROS as well as GSK3β and TAU. Thus, the universal role of vitamin D, E alone and in combinations could be the potential nutritional agents in restoring the sensitivity of neuronal cells towards insulin and delaying the pathophysiological progression of AD.

scholarly journals The Role of TGFβ Ligands and Signalling on Insulin Resistance in Skeletal Muscle in Women With PCOS

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A443-A444
Author(s):  
Alba Moreno-Asso ◽  
Luke C McIlvenna ◽  
Rhiannon K Patten ◽  
Andrew J McAinch ◽  
Raymond J Rodgers ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Insulin Signalling ◽  
Signalling Pathway ◽  
Whole Body ◽  
Insulin Signalling Pathway ◽  
Cultured Myotubes ◽  
Tgfβ Superfamily

Abstract Polycystic ovary syndrome (PCOS) is the most common female endocrinopathy affecting metabolic and reproductive health of 8–13% of reproductive-age women. Insulin resistance (IR) appears to underpin the pathophysiology of PCOS and is present in approximately 38–95% of women with PCOS. This underlying IR has been identified as unique from, but synergistic with, obesity-induced IR (1). Skeletal muscle accounts for up to 85% of whole-body insulin-stimulated glucose uptake; however, in PCOS this is reduced by about 27% when assessed by a euglycaemic-hyperinsulinaemic clamp (2). Interestingly, this reduced insulin-stimulated glucose uptake observed in skeletal muscle tissue is not retained in cultured myotubes (3), suggesting that in vivo environmental factors may play a role in this PCOS-specific IR. Yet, the molecular mechanisms regulating IR remain unclear (4). A potential environmental mechanism contributing to the development of peripheral IR may be the extracellular matrix remodelling and aberrant transforming growth factor beta (TGFβ) signalling. Previous work demonstrated that TGFβ superfamily ligands are involved in the increased collagen deposition and fibrotic tissue in the ovaries, and suggested that these ligands may be involved in the metabolic morbidity associated with PCOS (5). In this study, we investigated the effects of TGFβ1 (1, 5 ng/ml), and the Anti-Müllerian hormone (AMH; 5, 10, 30 ng/ml), a TGFβ superfamily ligand elevated in women with PCOS, as causal factors of IR in cultured myotubes from women with PCOS (n=5) and healthy controls (n=5). TGFβ1 did not have a significant effect on insulin signalling but induced expression of some ECM related genes and proteins, and increased glucose uptake via Smad2/3 signalling in myotubes from both groups. Conversely, AMH did not appear to activate the TGFβ/Smad signalling pathway and had no significant impact on insulin signalling or glucose uptake in any of the groups. In conclusion, these findings suggest that TGFβ1, but not AMH, may play a role in skeletal muscle ECM remodelling/fibrosis and glucose metabolism in PCOS but does not have a direct effect on insulin signalling pathway. Further research is required to elucidate its contribution to the development of in vivo skeletal muscle IR and broader impact in this syndrome. References: (1) Stepto et al., Hum Reprod 2013 Mar;28(3):777–784. (2) Cassar et al., Hum Reprod 2016 Nov;31(11):2619–2631. (3) Corbould et al., Am J Physiol-Endoc 2005 May;88(5):E1047-54. (4) Stepto et al., J Clin Endocrinol Metab, 2019 Nov 1;104(11):5372–5381. (5) Raja-Khan et al., Reprod Sci 2014 Jan;21(1):20–31.

scholarly journals The insulin signalling pathway

2002 ◽  
Vol 12 (7) ◽  
pp. R236-R238 ◽  
Author(s):  
Jose M. Lizcano ◽  
Dario R. Alessi
Keyword(s):  
Insulin Signalling ◽  
Signalling Pathway ◽  
Insulin Signalling Pathway

Effect of food restriction on the insulin signalling pathway in rat skeletal muscle and adipose tissue

2005 ◽  
Vol 16 (10) ◽  
pp. 602-609 ◽  
Author(s):  
Ana Alonso ◽  
Yolanda Fernández ◽  
Rebeca Fernández ◽  
Patricia Ordóñez ◽  
María Moreno ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Food Restriction ◽  
Insulin Signalling ◽  
Signalling Pathway ◽  
Rat Skeletal Muscle ◽  
Insulin Signalling Pathway ◽  
Effect Of Food

scholarly journals GPR21 Inhibition Increases Glucose-Uptake in HepG2 Cells

2021 ◽  
Vol 22 (19) ◽  
pp. 10784
Author(s):  
Gemma K. Kinsella ◽  
Stefania Cannito ◽  
Valentina Bordano ◽  
John C. Stephens ◽  
Arianna C. Rosa ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Hepg2 Cells ◽  
Insulin Signalling ◽  
Hepatic Insulin Resistance ◽  
In Vivo Studies ◽  
Negative Effects ◽  
Cellular Models ◽  
Insulin Signalling Pathway ◽  
Novel Strategy

GPR21 is a constitutively active, orphan, G-protein-coupled receptor, with in vivo studies suggesting its involvement in the modulation of insulin sensitivity. However, its precise contribution is not fully understood. As the liver is both a major target of insulin signalling and critically involved in glucose metabolism, the aim of this study was to examine the role of GPR21 in the regulation of glucose uptake and production in human hepatocytes. In particular, HepG2 cells, which express GPR21, were adopted as cellular models. Compared with untreated cells, a significant increase in glucose uptake was measured in cells treated with siRNA to downregulate GPR21 expression or with the GPR21-inverse agonist, GRA2. Consistently, a significantly higher membrane translocation of GLUT-2 was measured under these conditions. These effects were accompanied by an increased ratio of phAKT(Ser473)/tot-AKT and phGSK-3β(Ser9)/tot-GSK-3β, thus indicating a marked activation of the insulin signalling pathway. Moreover, a significant reduction in ERK activation was observed with GPR21 inhibition. Collectively, these results indicate that GPR21 mediates the negative effects on glucose uptake by the liver cells. In addition, they suggest that the pharmacological inhibition of GPR21 could be a novel strategy to improve glucose homeostasis and counteract hepatic insulin resistance.

scholarly journals Mulberry leaf reduces inflammation and insulin resistance in type 2 diabetic mice by TLRs and insulin Signalling pathway

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Simin Tian ◽  
Min Wang ◽  
Chenyue Liu ◽  
Hongbin Zhao ◽  
Baosheng Zhao
Keyword(s):  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Insulin Signalling ◽  
Signalling Pathway ◽  
Inflammatory Factor ◽  
Diabetic Mice ◽  
Mulberry Leaf ◽  
Insulin Signalling Pathway ◽  
Tnf Α ◽  
Necrosis Factor

Abstract Background It has been testified that Diabetes mellitus (DM) has a close association with chronic inflammation and Toll-like Receptors (TLRs), and DM could be prevented by mulberry leaf. Therefore, a hypothesis came into being that mulberry leaf could ameliorate proinflammation and insulin resistance (IR) through TLRs and insulin signalling pathways. Methods Water extracts of mulberry leaf (WEM) was given to diabetic mice by gavage for 10 weeks, and the diabetic mice was injected with low-dose streptozocin, fed with high-fat and high-sugar diet. Oral glucose tolerance tests (OGTTs) were conducted. At the same time, homeostasis model assessment of insulin (HOMA-IR) and the level of the inflammatory factor, tumour necrosis factor-α (TNF-α) was measured. The expressions of critical nodes of TLRs and insulin signalling pathway were also examined. Results WEM contributed to a significant decrease in fasting blood glucose, AUC from the investigation of OGTTs and HOMA-IR. The levels of the inflammatory factor, tumour necrosis factor-α (TNF-α) also declined. Moreover, WEM suppressed the expression of TLR2, myeloid differentiation primary-response protein 88 (MyD88), tumour-necrosis-factor receptor-associated factor 6 (TRAF6), nuclear factor kappa B (NF-κB) in the skeletal muscle. WEM could up-regulate the expression of insulin receptor (InsR) and insulin receptor substrate 1 (IRS1), and down-regulate the phosphorylation of IRS1 in adipose tissue. Conclusion Through this study, a conclusion could be made that WEM mitigates hyperglycemia, IR, and inflammation through the interactions among TLR2 signalling pathway, insulin signalling pathway and TNF-α.

scholarly journals S-resistin, a non secretable resistin isoform, impairs the insulin signalling pathway in 3T3-L1 adipocytes

2015 ◽  
Vol 71 (3) ◽  
pp. 381-390 ◽  
Author(s):  
María Rodríguez ◽  
Eduardo Moltó ◽  
Lidia Aguado ◽  
Nilda Gallardo ◽  
Antonio Andrés ◽  
...  
Keyword(s):  
Insulin Signalling ◽  
Signalling Pathway ◽  
Insulin Signalling Pathway
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