In vivo sodium tungstate treatment prevents E‐cadherin loss induced by diabetic serum in HK‐2 cell line

Abstract

Diabetic nephropathy (DN) is characterized by interstitial inflammation and fibrosis, which is the result of chronic accumulation of extracellular matrix produced by activated fibroblasts in the renal tubulointerstitium. Renal proximal tubular epithelial cells (PTECs), through the process of epithelial-to-mesenchymal transition (EMT), are the source of fibroblasts within the interstitial space, and loss of E-cadherin has shown to be one of the earliest steps in this event. Here, we studied the effect of the anti-diabetic agent sodium tungstate (NaW) in the loss of E-cadherin induced by transforming growth factor (TGF) β-1, the best-characterized in vitro EMT promoter, and serum from untreated or NaW-treated diabetic rats in HK-2 cell line, a model of human kidney PTEC. Our results showed that both TGFβ-1 and serum from diabetic rat induced a similar reduction in E-cadherin expression. However, E-cadherin loss induced by TGFβ-1 was not reversed by NaW, whereas sera from NaW-treated rats were able to protect HK-2 cells. Searching for soluble mediators of NaW effect, we compared secretion of TGFβ isoforms and vascular endothelial growth factor (VEGF)-A, which have opposite actions on EMT. One millimolar NaW alone reduced secretion of both TGFβ-1 and -2, and stimulated secretion of VEGF-A after 48 h. However, these patterns of secretion were not observed after diabetic rat serum treatment, suggesting that protection from E-cadherin loss by serum from NaW-treated diabetic rats originates from an indirect rather than a direct effect of this salt on HK-2 cells, via a mechanism independent of TGFβ and VEGF-A functions.

Anti‐Diabetic Agent Sodium Tungstate Induces the Secretion of Pro‐ and Anti‐Inflammatory Cytokines by Human Kidney Cells

“…Here we show that IL‐1β, TNF‐α, and IFN‐γ were not intrinsically produced by N‐ or D‐RPTEC, and NaW was unable to induce their secretion under our experimental conditions. Furthermore, NaW reduced TGFβ‐1 secretion by another model of RPTEC (HK‐2 cell line) (Bertinat et al, ), suggesting that NaW treatment might be beneficial to renal fibrosis through a negative effect on the TGFβ axis. Besides, eotaxin, and IP‐10 secretion was low but increased in a time‐dependent manner (Fig.…”

“…Human pancreatic duct cells can produce and release both IL‐8 and vascular endothelial growth factor (VEGF) at levels that can stimulate angiogenesis and survival of islet cell grafts (Movahedi et al, ). Interestingly, RPTECs also secrete VEGF in response to NaW (Bertinat et al, ). Given that peritubular capillaries are essential for the normal structure and function of renal tubules, and that tubulointerstitial injury and fibrosis induce loss of these capillaries (Tanaka and Nangaku, ), NaW‐dependent secretion of VEGF and IL‐8 by RPTEC may participate in revascularization of the tubulointerstitial space.…”

“…NaW treatment has been shown to recover the number and function of immune cells as well as the immunoglobulin level in diabetic rats (Palanivel and Sakthisekaran, ), and it also completely reverses the most characteristic histopathological feature of the diabetic kidney, the so‐called Armanni–Ebstein lesion, which is an extensive glycogen deposition in tubular cells (Barbera et al, ). In vitro, NaW has shown to indirectly prevent loss of epithelial integrity in a model of human RPTEC in the context of diabetes (Bertinat et al, ). However, any direct anti‐inflammatory effect of NaW has not been addressed yet.…”

Sodium tungstate: Is it a safe option for a chronic disease setting, such as diabetes?

“…Diabetes has been associated with a higher risk of cancer in T2D patients, which is proposed to be mediated by chronic ↓ STZ diabetic rats Bertinat, Silva, et al (2015) ↓ irs2 −/− diabetic mice Bertinat et al (2018) Hepatic glucose or glycogen metabolism N STZ diabetic rats Barberà et al (2001Barberà et al ( , 1994 N ZDF diabetic rats Muñoz et al (2001) N STZ diabetic rats Nocito et al (2012) = irs2 −/− diabetic mice Oliveira et al (2014) Food intake or weight gain ↓ STZ diabetic rats Barberà et al (2001Barberà et al ( , 1994 ↓ Renal glycogen accumulation ↓ STZ diabetic rats Barberà et al (2001) Note. =: no effect; ↓: decrease; ↑: increase; irs2 −/− : insulin receptor substrate-2 knockout; N: normalization; Na 2 WO 4 : sodium tungstate; STZ: streptozotocin; ZDF: Zucker diabetic fatty.…”

“…BU-11 cell line (in vitro) Guilbert et al (2011) ↑ Primary murine bone marrow-derived developing B lymphocytes (in vitro) Guilbert et al (2011) Cell cycle arrest ↑ Human peripheral blood lymphocytes (in vitro) Osterburg et al (2010) ↑ BU-11 cell line (in vitro) Guilbert et al (2011) ↑ BMS2 cell line (in vitro) Guilbert et al (2011) ↑ Primary murine bone marrow-derived developing B lymphocytes (in vitro) Guilbert et al (2011) ↑ PC-3 cell line (in vitro) Liu et al (2012) ↑ HK-2 cell line (in vitro) Bertinat, Silva, et al (2015) Histone methylation ↑ A549 cell line (in vitro) Laulicht-Glick et al (2017) ↑ BEAS-2B cell line (in vitro) Laulicht-Glick et al (2017) ↑ Liver from A/J mice (in vivo) Laulicht-Glick et al (2017) B-lymphocyte development ↓ B lymphocytes from C57BL/6J mice (in vivo) Kelly et al (2013) Immune response ↓ C57BL/6J mice (in vivo) Osterburg et al (2014) ↓ B 6 C 3 F 1 /N mice (in vivo) Frawley et al (2016) Carcinogenesis ↑ BEAS-2B cells injected in nude mice a Laulicht et al (2015) Breast cancer metastasis ↑ BALB/c mice (in vivo) Bolt et al (2015) Renal histopathological alterations ↑ Sprague-Dawley rats (in vivo) McCain et al (2015)Renal glycogen accumulation ↑ irs2 −/− diabetic mice (in vivo)Bertinat et al (2018) VEGF-A secretion ↑ HK-2 cell line (in vitro)Bertinat, Silva, et al (2015) IL-6, IL-8, MCP-1 secretion ↑ Primary cultures of human RPTEC (in vitro)Bertinat et al (2017) …”