TNF-α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant Hepatocytes
One of the major mechanisms of hyperglycemia in type 2 diabetes is insulin resistance (IR) which can induce free fatty acids like palmitate. In hepatic cell, as an insulin target tissue, insulin resistance can be stimulated by inflammatory cytokine TNF-α. The interaction of intracellular TNF-α signa...
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| Format: | Article |
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Wiley
2019-01-01
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| Series: | Mediators of Inflammation |
| Online Access: | http://dx.doi.org/10.1155/2019/3560819 |
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| author | Iraj Alipourfard Nelly Datukishvili Davit Mikeladze |
| author_facet | Iraj Alipourfard Nelly Datukishvili Davit Mikeladze |
| author_sort | Iraj Alipourfard |
| collection | DOAJ |
| description | One of the major mechanisms of hyperglycemia in type 2 diabetes is insulin resistance (IR) which can induce free fatty acids like palmitate. In hepatic cell, as an insulin target tissue, insulin resistance can be stimulated by inflammatory cytokine TNF-α. The interaction of intracellular TNF-α signal with the insulin signaling pathway is not well identified. Hence, we aimed to investigate the effect of TNF-α elimination on the diabetic model of palmitate-induced insulin-resistant hepatocytes (HepG2). The changes of phosphorylation rate in IRS-1 protein are determined to know the effect of TNF-α on this key protein of the insulin signaling pathway. HepG2 cells were treated with 0.5 Mm palmitate, and TNF-α gene knockdown was performed by shRNA-mediated technique. Western blot analysis was used to evaluate the phosphorylated activity of the insulin signaling pathway. Palmitate-induced IR could increase TNF-α protein expression 1.2-, 2.78-, and 2.25-fold compared to the control cells at times of 8 h, 16 h, and 24 h, respectively. TNF-α expression in downregulated cells transfected with shRNA-TNF-α is approximately 47.0% of normal cells and 49.0% in the case of scrambled cells. IRS-1 phosphorylation in TNF-α-downregulated and stimulated cells with 100 nM insulin, after treatment and in the absence of palmitate, was 45% and 29% higher than the normal cells. These data support the evidence that TNF-α downregulation strategy contributes to the improvement of IRS-1 phosphorylation after insulin stimulation and insulin response in HepG2 liver cells. |
| format | Article |
| id | doaj-art-209a2220c8184c4982c95fbef32dc6be |
| institution | OA Journals |
| issn | 0962-9351 1466-1861 |
| language | English |
| publishDate | 2019-01-01 |
| publisher | Wiley |
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| series | Mediators of Inflammation |
| spelling | doaj-art-209a2220c8184c4982c95fbef32dc6be2025-08-20T02:03:55ZengWileyMediators of Inflammation0962-93511466-18612019-01-01201910.1155/2019/35608193560819TNF-α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant HepatocytesIraj Alipourfard0Nelly Datukishvili1Davit Mikeladze2Institute of Chemical Biology, School of Natural Sciences and Engineering, Ilia State University, Tbilisi 0162, GeorgiaInstitute of Chemical Biology, School of Natural Sciences and Engineering, Ilia State University, Tbilisi 0162, GeorgiaInstitute of Chemical Biology, School of Natural Sciences and Engineering, Ilia State University, Tbilisi 0162, GeorgiaOne of the major mechanisms of hyperglycemia in type 2 diabetes is insulin resistance (IR) which can induce free fatty acids like palmitate. In hepatic cell, as an insulin target tissue, insulin resistance can be stimulated by inflammatory cytokine TNF-α. The interaction of intracellular TNF-α signal with the insulin signaling pathway is not well identified. Hence, we aimed to investigate the effect of TNF-α elimination on the diabetic model of palmitate-induced insulin-resistant hepatocytes (HepG2). The changes of phosphorylation rate in IRS-1 protein are determined to know the effect of TNF-α on this key protein of the insulin signaling pathway. HepG2 cells were treated with 0.5 Mm palmitate, and TNF-α gene knockdown was performed by shRNA-mediated technique. Western blot analysis was used to evaluate the phosphorylated activity of the insulin signaling pathway. Palmitate-induced IR could increase TNF-α protein expression 1.2-, 2.78-, and 2.25-fold compared to the control cells at times of 8 h, 16 h, and 24 h, respectively. TNF-α expression in downregulated cells transfected with shRNA-TNF-α is approximately 47.0% of normal cells and 49.0% in the case of scrambled cells. IRS-1 phosphorylation in TNF-α-downregulated and stimulated cells with 100 nM insulin, after treatment and in the absence of palmitate, was 45% and 29% higher than the normal cells. These data support the evidence that TNF-α downregulation strategy contributes to the improvement of IRS-1 phosphorylation after insulin stimulation and insulin response in HepG2 liver cells.http://dx.doi.org/10.1155/2019/3560819 |
| spellingShingle | Iraj Alipourfard Nelly Datukishvili Davit Mikeladze TNF-α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant Hepatocytes Mediators of Inflammation |
| title | TNF-α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant Hepatocytes |
| title_full | TNF-α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant Hepatocytes |
| title_fullStr | TNF-α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant Hepatocytes |
| title_full_unstemmed | TNF-α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant Hepatocytes |
| title_short | TNF-α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant Hepatocytes |
| title_sort | tnf α downregulation modifies insulin receptor substrate 1 irs 1 in metabolic signaling of diabetic insulin resistant hepatocytes |
| url | http://dx.doi.org/10.1155/2019/3560819 |
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