Elsevier

Chemico-Biological Interactions

Volume 278, 25 December 2017, Pages 48-53
Chemico-Biological Interactions

Salidroside alleviates high glucose-induced oxidative stress and extracellular matrix accumulation in rat glomerular mesangial cells by the TXNIP-NLRP3 inflammasome pathway

https://doi.org/10.1016/j.cbi.2017.10.012Get rights and content

Highlights

  • SAL inhibits HG-induced cell proliferation in HBZY-1 cells.

  • SAL alleviates HG-induced oxidative stress.

  • SAL reduces HG-induced ECM accumulation.

  • SAL inhibits HG-induced TXNIP-NLRP3 inflammasome activation.

Abstract

Diabetic nephropathy (DN) is a metabolic disease characterized by mesangial cell proliferation and extracellular matrix (ECM) accumulation. Salidroside (SAL) is the major ingredient in Rhodiola rosea and possesses beneficial effects on DN. This study aimed to evaluate the effect of SAL on high glucose (HG)-induced oxidative stress and ECM accumulation and the underlying mechanism. Rat glomerular mesangial cells HBZY-1 were induced by high glucose (HG) in the presence or absence of SAL. Cell proliferation was measured by CCK-8 assay. The reactive oxygen species (ROS) level, malondialdehyde (MDA) level and superoxide dismutase (SOD) activity were detected to evaluate oxidative stress. The expression levels of ECM proteins including fibronectin (FN) and type IV collagen (Coll IV) were detected by qRT-PCR and western blot analysis. The expressions of thioredoxin-interacting protein (TXNIP), nod-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing CARD (ASC), and caspase-1 were assessed by western blot. Si-TXNIP or si-NC was transfected into HBZY-1 cells to inhibit TXNIP-NLRP3 inflammasome pathway. The results showed that SAL treatment alleviated HG-induced cell proliferation. SAL reduced the levels of ROS and MDA, and induced the SOD activity. Besides, the mRNA and protein expressions of FN and Coll IV were decreased by SAL. The expression levels of TXNIP, NLRP3, ASC, and caspase-1 were reduced in the SAL treated cells. In addition, TXNIP knockdown inhibited TXNIP-NLRP3 inflammasome activation and suppressed HG-induced cell proliferation, oxidative stress, and ECM accumulation. In conclusion, SAL alleviated HG-induced oxidative stress and ECM accumulation in rat glomerular mesangial cells by the TXNIP-NLRP3 inflammasome pathway.

Introduction

Diabetic nephropathy (DN) is the major cause of end stage renal disease and closely associated with the mortality rate of diabetic patients [1], [2]. It has been proved that DN is characterized by thickened tubular basal and glomerular membranes, mesangial cell proliferation and accumulation of extracellular matrix (ECM) [1], [3]. Growing evidences prove that DN is induced by various conditions, including glucose metabolism disorder, oxidative stress, inflammatory factors and cytokines [3].

Nod-like receptor protein 3 (NLRP3) inflammasome is a polyprotein complex which plays an important role in the process of inflammation [4]. The NLRP3 inflammasome consists of three inflammasome components, NLRP3, apoptosis-associated speck-like protein containing CARD (ASC), and caspase-1 or caspase-5 [5]. It is crucial for DN that NLRP3 inflammasome detects the endogenous danger signals and activates the cytokines, and then stimulate the inflammatory reaction [6]. Moreover, the NLRP3 inflammasome is activated by oxidative stress, hyperglycaemia and growth factors in a variety of cell types in DN [6], [7].

Salidroside (SAL), 2-(4-hydroxyphenyl)-ethyl--d-glucopyranoside, is the major ingredient in Rhodiola rosea, which is a herbal plant and possesses protective effects against early nephropathy in diabetic rat [8]. It has been reported that SAL has broad pharmacological activities, such as antidiabetic, hepatoprotective, and antioxidative effects [9], [10], [11]. SAL also possesses beneficial effects on DN and affects the high-glucose (HG)-induced mesangial cell proliferation [12]. However, the effect of SAL on HG-induced DN in rat glomerular mesangial cells is still incompletely understood.

In the present study, the effect of SAL on HG-induced oxidative stress and ECM accumulation and the underlying mechanism was investigated. We found that SAL alleviated HG-induced oxidative stress and ECM accumulation in rat glomerular mesangial cells by the TXNIP-NLRP3 inflammasome pathway. The results indicated that SAL might be a useful agent for preventing the development and progression of DN.

Section snippets

Cell culture and treatment

Rat glomerular mesangial cell line HBZY-1 was purchased from KeyGen Biotechnology (Nanjing, China). Cells were cultured in Dulbecco's modified eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 100 U/ml penicillin and 100 mg/ml streptomycin in a humidified atmosphere of 5% CO2 at 37 °C. The HBZY-1 cells were stimulated with various concentrations of SAL (20 or 40 μM; Sigma, St. Louis, MO, USA) in the presence of normal glucose (NG, 5.5 mM), high glucose (HG, 30 mM) or

SAL inhibits HG-induced cell proliferation

It has been reported that HG induces cell proliferation in mesangial cells [13]. To evaluate the effect of SAL on HG-induced cell proliferation in HBZY-1 cells, CCK-8 assay was performed in this study. As shown in Fig. 1A and B, the cell proliferation was not altered by either normal glucose or mannitol. HG significantly induced cell proliferation of HBZY-1 cells. However, SAL (20 or 40 μM) treatment alleviated HG-induced cell proliferation (Fig. 1C).

SAL alleviates HG-induced oxidative stress

It is known that oxidative stress plays an

Discussion

It is known that HG concentrations affect many types of cells in the kidney including mesangial cells [14]. Previous studies reported that glucose induced oxidative stress in mesangial cells [14], [15], [18]. Glucose not only promotes generation of ROS but also attenuates the antioxidant. Besides, glucose exposure stimulates the increased accumulation of ECM protein in DN [14]. It has been demonstrated that HG concentration suppresses human mesangial cell proliferation and stimulates

Conflicts of interest

The authors declare that they have no competing interests.

Acknowledgements

This work was financially supported by Scientific and technological Key Project of Henan Province (No. 201003089).

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    These authors contributed equally to this work.

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