267-OR: Cardiomyocyte Insulin Resistance Manifests on High-Glucose Fibroblast-Derived Extracellular Matrix

Impaired action of insulin in skeletal muscle, termed insulin resistance, leads to increased blood glucose levels resulting in compensatory increase in insulin levels. The elevated blood glucose and insulin levels exacerbate insulin resistance and contribute to the pathogenesis of type 2 diabetes mellitus (T2DM). In previous studies we found attenuation of free fatty acid-induced muscle cell insulin resistance by rosemary extract (RE). In the present study we investigated the effects of RE on high glucose (HG) and high insulin (HI)-induced muscle cell insulin resistance. Exposure of L6 myotubes to 25 mM glucose and 100 nM insulin for 24 h, to mimic hyperglycemia and hyperinsulinemia, abolished the acute insulin-stimulated glucose uptake, increased the serine phosphorylation of IRS-1 and the phosphorylation/ activation of mTOR and p70S6K. Treatment with RE significantly improved the insulin-stimulated glucose uptake and increased the acute insulin-stimulated tyrosine phosphorylation while reduced the HG+HI-induced serine phosphorylation of IRS-1 and phosphorylation of mTOR and p70S6K. Additionally, treatment with RE significantly increased the phosphorylation of AMPK, its downstream effector ACC and the plasma membrane GLUT4 levels. Our data indicate a potential of RE to counteract muscle cell insulin resistance and more studies are required to investigate its effectiveness in vivo. Novelty: • Rosemary extract (RE) phosphorylated muscle cell AMPK and ACC under both normal and high glucose (HG)/high insulin (HI) conditions. • The HG/HI-induced serine phosphorylation of IRS-1 and activation of mTOR and p70S6K were attenuated by RE. • RE increased the insulin-stimulated glucose uptake by enhancing GLUT4 glucose transporter translocation to plasma membrane.

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Increased extracellular matrix synthesis and mRNA in mesangial cells grown in high-glucose medium

AJP Renal Physiology ◽

10.1152/ajprenal.1991.260.2.f185 ◽

1991 ◽

Vol 260 (2) ◽

pp. F185-F191 ◽

Cited By ~ 16

Author(s):

S. H. Ayo ◽

R. A. Radnik ◽

W. F. Glass ◽

J. A. Garoni ◽

E. R. Rampt ◽

...

Keyword(s):

Extracellular Matrix ◽

Protein Synthesis ◽

High Glucose ◽

Mesangial Cells ◽

Matrix Proteins ◽

Cell Protein ◽

Enzyme Linked Immunosorbent Assay ◽

Mrna Levels ◽

Glomerular Mesangial Cells ◽

Glomerular Mesangium

Nodular expansion of glomerular mesangium with increased amounts of extracellular matrix (ECM) material is pathognomic of diabetic nephropathy. The precise mechanisms involved in this accumulation are unknown. Recently, we reported using a solid-phase enzyme-linked immunosorbent assay (ELISA) technique that glomerular mesangial cells, the principal cell type residing in glomerular mesangium, accumulate 50–60% more fibronectin (FN), laminin (LM), and type IV collagen (T-IV) when cultured in medium containing high glucose (30 mM) (S. H. Ayo, R. A. Rodnik, J. Garoni, W. F. Glass II, and J. I. Kreiberg. Am. J. Pathol. 136: 1339-1348, 1990). ECM assembly is controlled by its rate of synthesis and degradation, as well as its binding and rate of incorporation into the ECM. To elucidate the mechanisms involved, pulse-chase experiments were designed to estimate ECM protein synthesis from the incorporation of Trans-35S [( 35S]methionine, [35S]cysteine) into immunoprecipitated FN, LM, and T-IV. mRNA levels were examined, and degradation rates were estimated from the disappearance of radioactivity from matrix proteins in mesangial cells previously incubated with Trans-35S. One week of growth in 30 mM glucose resulted in approximately 40–50% increase in the synthesis of all three matrix proteins compared with 10 mM glucose-grown cells. This was accompanied by a significant increase in the transcripts for all three matrix proteins (approximately twofold). The specific activity of the radiolabel in trichloroacetic acid-precipitable cell protein showed no difference between cells grown in 10 or 30 mM glucose, indicating that total protein synthesis was unchanged. After 1 wk, the rate of FN, LM, and T-IV collagen degradation was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

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Insulin resistance induced by high glucose and high insulin precedes insulin receptor substrate 1 protein depletion in human adipocytes

Metabolism ◽

10.1016/j.metabol.2006.09.012 ◽

2007 ◽

Vol 56 (2) ◽

pp. 190-198 ◽

Cited By ~ 30

Author(s):

Frida Renström ◽

Jonas Burén ◽

Maria Svensson ◽

Jan W. Eriksson

Keyword(s):

Insulin Resistance ◽

Insulin Receptor ◽

High Glucose ◽

Insulin Receptor Substrate ◽

Human Adipocytes ◽

Insulin Receptor Substrate 1 ◽

Protein Depletion ◽

High Insulin

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Adenosine A1 Receptor Deficiency Aggravates Extracellular Matrix Accumulation in Diabetic Nephropathy through Disturbance of Peritubular Microenvironment

Journal of Diabetes Research ◽

10.1155/2021/5584871 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Dongli Tian ◽

Jiaying Li ◽

Linfeng Zou ◽

Min Lin ◽

Xiaoxiao Shi ◽

...

Keyword(s):

Extracellular Matrix ◽

Diabetic Nephropathy ◽

High Glucose ◽

Immunohistochemical Staining ◽

Adenosine A1 Receptor ◽

Pronounced Increase ◽

Matrix Deposition ◽

Adenosine A1 ◽

Proximal Tubular ◽

A1 Receptor

Background. We previously observed that adenosine A1 receptor (A1AR) had a protective role in proximal tubular megalin loss associated with albuminuria in diabetic nephropathy (DN). In this study, we aimed to explore the role of A1AR in the fibrosis progression of DN. Methods. We collected DN patients’ samples and established a streptozotocin-induced diabetes model in wild-type (WT) and A1AR-deficient (A1AR-/-) mice. The location and expression of CD34, PDGFRβ, and A1AR were detected in kidney tissue samples from DN patients by immunofluorescent and immunohistochemical staining. We also analyzed the expression of TGFβ, collagen (I, III, and IV), α-SMA, and PDGFRβ using immunohistochemistry in WT and A1AR-/- mice. CD34 and podoplanin expression were analyzed by Western blotting and immunohistochemical staining in mice, respectively. Human renal proximal tubular epithelial cells (HK2) were cultured in medium containing high glucose and A1AR agonist as well as antagonist. Results. In DN patients, the expression of PDGFRβ was higher with the loss of CD34. The location of PDGFRβ and TGFβ was near to each other. The A1AR, which was colocalized with CD34 partly, was also upregulated in DN patients. In WT-DN mice, obvious albuminuria and renal pathological leisure were observed. In A1AR-/- DN mice, more severe renal tubular interstitial fibrosis and more extracellular matrix deposition were observed, with lower CD34 expression and pronounced increase of PDGFRβ. In HK2 cells, high glucose stimulated the epithelial-mesenchymal transition (EMT) process, which was inhibited by A1AR agonist. Conclusion. A1AR played a critical role in protecting the tubulointerstitial fibrosis process in DN by regulation of the peritubular microenvironment.

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miR-450a-5p eliminats MGO-induced insulin resistance via targeting CREB

10.21203/rs.2.12119/v1 ◽

2019 ◽

Author(s):

Cuifeng Wei ◽

Li Meng ◽

Yuting Zhang

Keyword(s):

Insulin Resistance ◽

Endothelial Cells ◽

Cell Invasion ◽

High Glucose ◽

Target Gene ◽

Cell Activity ◽

Luciferase Reporter ◽

Akt Pathway ◽

Potential Target ◽

In Cells

Abstract Background miR-450a-5p was involved in fat formation, but its role in insulin resistance remains unclear. This study further investigated the effects of miR-450a-5p in endothelial cells, with the aim of finding a potential target for diabetes mellitus. Methods Human umbilical vein endothelial cells (HUVECs) were severally treated with low-glucose, high-glucose, methylglyoxal (MGO), and insulin only or plus MGO. miR-450a-5p was up-regulated or down-regulated in treated HUVECs. miR-450a-5p expression in cells was measured by quantitative real-time polymerase chain reaction (qRT-PCR) assays. The cell activity was determined through MTT experiments. Transwell assay and oil red O staining were used for the detection of cell invasion and fat formation. The expressions of eNOS/AKT pathway-related proteins in cells were assessed by Western blot (WB) analysis. Furthermore, the target gene of miR-450a-5p was analyzed by double-luciferase reporter analysis, and its influence in eNOS/AKT pathway was estimated. Results miR-450a-5p decreased obviously in endothelial cells with high-glucose and MGO. Through in vitro cell experiments, we knew that MGO could not only intensify the activity of endothelial cells, but also accelerate cell invasion and fat accumulation, which could be reversed by up-regulated miR-450a-5p. Moreover, MGO inhibited eNOS/AKT pathway activation and NO release mediated by insulin, which were eliminated by up-regulated miR-450a-5p. Furthermore, CREB was the target gene of miR-450a-5p that had an activation effect on the eNOS/AKT pathway. Conclusions Up-regulated miR-450a-5p eliminated MGO-induced insulin resistance via targeting CREB, which might be a potential target to improve insulin resistance and benefit patients with related diseases.

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Protocatechuic acids protects against high glucose- induced insulin resistance in human visceral adipose tissue

Problems of Endocrinology ◽

10.14341/probl201662545-46 ◽

2016 ◽

Vol 62 (5) ◽

pp. 45-46

Author(s):

Paulina Ormazabal ◽

Beatrice Scazzocchio ◽

Rosaria Varì ◽

Annunziata Iacovelli ◽

Roberta Masella

Keyword(s):

Insulin Resistance ◽

Adipose Tissue ◽

Visceral Adipose Tissue ◽

High Glucose ◽

Protective Role ◽

Insulin Sensitizer ◽

20 Nm ◽

Visceral Adipose

Adipocytes exposed to high glucose concentrations exhibit impaired insulin signaling. Binding of insulin to its membrane receptor activates insulin metabolic pathway leading to IRS-1 and AKT phosphorylations. The accumulation of visceral adipose tissue (VAT) correlates with insulin resistance and metabolic syndrome. Anthocyanins (ACN) are bioactive food compounds of great nutritional interest. We have shown that protocatechuic acid (PCA), a major metabolite of ACN, might exert insulin-sensitizer activities in human visceral adipose tissue. The aim of this work was to define the protective role of PCA against insulin-resistance induced by high glucose in VAT.Methodology: VAT obtained from control subject (BMI≤25) were separated in four experimental groups: i) PCA: samples treated for 24 h with 100 μM PCA, ii) GLU: VAT treated with 30 mM glucose for 24 h, iii) PCA+GLU: 1 hour incubation with 100 μM PCA before adding glucose (30 mM, 24 h), iv) CTR: vehicle. After treatment, VAT groups were (or not) acutely stimulated with insulin (20 nM, 20 min). Tyr-IRS-1 and Ser-Akt phosphorylations were assessed by Western blotting (WB) in basal or insulin stimulated tissues in all experimental groups. Samples were assessed for IRS-1, IR, Akt and GLUT4 protein content by WB. Results: No differences in protein contents between experimental groups were found. GLU tissues showed a lower increment in insulin-stimulated phosphorylation of IRS-1 and Akt compared to CTR and PCA samples. This impaired activation was completely reversed by the pretreatment with PCA.Conclusion: An in-vitro insulin-resistance condition induced by high glucose was established in biopsies of VAT. PCA restores the ability of GLU-tissues to fully respond to insulin by increasing IRS-1 and Akt phosphorylations. These results confirm the insulin-sensitizer effect of PCA on VAT previously reported by our group. An anthocyanin rich diet might help to protect against insulin-resistance in VAT.

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AGEs and Glucose Levels Modulate Type I and III Procollagen mRNA Synthesis in Dermal Fibroblasts Cells Culture

Experimental Diabetes Research ◽

10.1155/2008/473603 ◽

2008 ◽

Vol 2008 ◽

pp. 1-7 ◽

Cited By ~ 24

Author(s):

Serban Iren Andreea ◽

Costache Marieta ◽

Dinischiotu Anca

Keyword(s):

Extracellular Matrix ◽

High Glucose ◽

Dermal Fibroblasts ◽

Type I ◽

Dependent Manner ◽

Human Dermal Fibroblasts ◽

Mrna Synthesis ◽

Quantitative Real Time Pcr ◽

Glucose Levels ◽

Dose Dependent

In the dermis, fibroblasts play an important role in the turnover of the dermal extracellular matrix. Collagen I and III, the most important dermal proteins of the extracellular matrix, are progressively altered during ageing and diabetes. For mimicking diabetic conditions, the cultured human dermal fibroblasts were incubated with increasing amounts of AGE-modified BSA andD-glucose for 24 hours. The expression of procollagenα2(I) and procollagenα1(III) mRNA was analyzed by quantitative real-time PCR. Our data revealed that the treatment of fibroblasts with AGE-modified BSA upregulated the expression of procollagenα2(I) and procollagenα1(III) mRNA in a dose-dependent manner. High glucose levels mildly induced a profibrogenic pattern, increasing the procollagenα2(I) mRNA expression whereas there was a downregulation tendency of procollagenα1(III) mRNA.

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