Retraction statement: ‘Urotensin II inhibits autophagy in renal tubular epithelial cells and induces extracellular matrix production in early diabetic mice’ by Guan‐Jong Chen, Fei Wu, Xin‐Xin Pang, Ai‐Hua Zhang, Jun‐Bao Shi, Min Lu and Chao‐Shu Tang

Actoeside mitigated the renal proximal tubule cells damage triggered by high glucose through miR-766/VCAM1/NF-κB signalling pathway

CONTEXT

Diabetic nephropathy (DN) triggered by diabetes mellitus is one of the primary causes of end-stage renal failure worldwide.

OBJECTIVE

This study intends to explore the function and potential mechanism of actoeside on renal proximal tubule (HK-2) cells damage induced by high-glucose (HG).

METHODS

The DN model was established in HK-2 cells with 30 mM HG treatment. The viability, apoptosis and inflammation of HK-2 cells were analysed severally via CCK-8, flow cytomery and ELISA. The key factors related to NF-κB were detected by western blotting.

RESULTS

Actoeside attenuated the HG-induced HK-2 cells damage. The differentially expression of miR-766 and VCAM1 in DN patients was reversed by actoeside. Moreover, the increased phosphorylation levels of p65 NF-κB/IκBα induced by HG were attenuated by actoeside.

CONCLUSIONS

Actoeside promoted the growth and repressed the apoptosis and inflammation of HK-2 cells via miR-766/VCAM1/NF-κB signalling pathway, affording a promising idea for the treatment of DN.

Glucose and Blood Pressure-Dependent Pathways-The Progression of Diabetic Kidney Disease

The major clinical associations with the progression of diabetic kidney disease (DKD) are glycemic control and systemic hypertension. Recent studies have continued to emphasize vasoactive hormone pathways including aldosterone and endothelin which suggest a key role for vasoconstrictor pathways in promoting renal damage in diabetes. The role of glucose per se remains difficult to define in DKD but appears to involve key intermediates including reactive oxygen species (ROS) and dicarbonyls such as methylglyoxal which activate intracellular pathways to promote fibrosis and inflammation in the kidney. Recent studies have identified a novel molecular interaction between hemodynamic and metabolic pathways which could lead to new treatments for DKD. This should lead to a further improvement in the outlook of DKD building on positive results from RAAS blockade and more recently newer classes of glucose-lowering agents such as SGLT2 inhibitors and GLP1 receptor agonists.

Diabetic Nephropathy Assessment: Microtubule-Associated Protein 1 Light-Chain 3B a New Promising Biomarker

Autophagy is a highly conserved pathway. Impairment of autophagy is implicated in the pathogenesis of diabetic nephropathy. The current study applied a bioinformatics analysis to retrieve promising autophagy biomarker relevant diabetic nephropathy. Urinary expression of Microtubule-associated protein 1 light-chain 3B (LC3B) RNA was assessed. Urine samples of 86 type II diabetic kidney disease Egyptian patients (albuminuria group) were provided to quantify urinary expression of LC3B. A group of 30 healthy volunteers were also enrolled in addition to non-albuminuria group including 44 patients. Our study revealed a cut-off value for urinary LC3B expression level that was calculated by receiver-operating characteristic curve as 0.866. Sensitivity and specificity of LC3B were 83.7 and 78.4% respectively. The positivity rate of urinary LC3B expression level was significantly lower in diabetic nephropathy patients than control group. LC3B has great clinical value as promising biomarker in diabetic nephropathy assessment.

Renal tubular epithelial cells: the neglected mediator of tubulointerstitial fibrosis after injury

Renal fibrosis, especially tubulointerstitial fibrosis, is the inevitable outcome of all progressive chronic kidney diseases (CKDs) and exerts a great health burden worldwide. For a long time, interests in renal fibrosis have been concentrated on fibroblasts and myofibroblasts. However, in recent years, growing numbers of studies have focused on the role of tubular epithelial cells (TECs). TECs, rather than a victim or bystander, are probably a neglected mediator in renal fibrosis, responding to a variety of injuries. The maladaptive repair mechanisms of TECs may be the key point in this process. In this review, we will focus on the role of TECs in tubulointerstitial fibrosis. We will follow the fate of a tubular cell and depict the intracellular changes after injury. We will then discuss how the repair mechanism of tubular cells becomes maladaptive, and we will finally discuss the intercellular crosstalk in the interstitium that ultimately proceeds tubulointerstitial fibrosis.

Effect of urotensin II/urotensin II receptor system on autophagy in acute liver failure in mice

AIM

To investigate the effect of urotensin II/urotensin II receptor (UII/UT) system on the levels of hepatic autophagy in mice with acute liver failure (ALF).

METHODS

Male Balb/c mice were randomly divided into four groups (n = 6 each): normal controls (group A), pre-treated controls (group B), model mice (group C), and pre-treated model mice (group D). Groups B and D received urantide (0.6 mg/kg body weight) via caudal vein injection. At 30 min post-injection, groups C and D were intraperitoneally injected with LPS/D-GalN to induce acute liver injury. Serum and liver tissue samples were collected 6 h later. Serum alanine transaminase (ALT) and aspartate aminotransferase (AST) levels were determined to assess liver injury. The expression of autophagy related genes such as Beclin-1, autophagy related 5 (Atg5), Atg7, sequestosome 1 (Sqstm1/p62), and microtubule-associated protein 1 light chain 3 (LC3) was detected by quantitative PCR. The expression of autophagic proteins LC3 and p62 was tested by Western blot.

RESULTS

Serum ALT and AST levels in group C were significantly higher than those in groups A and B (P < 0.01), while they were significantly lower in group D than in group C (P < 0.01). RT-PCR analysis showed that the expression of autophagy related genes such as Beclin-1, Atg5, Atg7, p62, LC3 was downregulated in groups C and D compared to groups A and B (P < 0.05), although there was no difference between groups C and D as well as between groups A and B (P > 0.05). LC3II and p62 protein levels tested by Western blot were significantly lower in groups C and D than in groups A and B (P < 0.05), but there was no difference between groups C and D as well as between groups A and B (P > 0.05).

CONCLUSION

UII/UT system has no influence on the suppressed hepatic autophagy in ALF mice.

Tangshen formula attenuates diabetic renal injuries by upregulating autophagy via inhibition of PLZF expression

The Chinese herbal granule Tangshen Formula (TSF) has been proven to decrease proteinuria and improve estimated glomerular filtration rate (eGFR) in diabetic kidney disease (DKD) patients. However, the underlying mechanism of TSF on treatment of diabetic nephropathy (DN) remains unclear. The present study aimed to identify the therapeutic target of TSF in diabetic renal injuries through microarray-based gene expression profiling and establish its underlying mechanism. TSF treatment significantly attenuated diabetic renal injuries by inhibiting urinary excretion of albumin and renal histological injuries in diabetic (db/db) mice. We found that PLZF might be the molecular target of TSF in DN. In vivo, the db/db mice showed a significant increase in renal protein expression of PLZF and collagen III, and decrease in renal autophagy levels (downregulated LC3 II and upregulated p62/SQSTM1) compared to db/m mice. The application of TSF resulted in the downregulation of PLZF and collagen III and upregulation of autophagy level in the kidneys of db/db mice. In vitro, TSF reduced high glucose (HG)-induced cell proliferation for NRK52E cells. Further studies indicated that the exposure of NRK52E cells to high levels of glucose resulted in the downregulation of cellular autophagy and upregulation of collagen III protein, which was reversed by TSF treatment by decreasing PLZF expression. In conclusion, TSF might have induced cellular autophagy by inhibiting PLZF expression, which in turn resulted in an increase in autophagic degradation of collagen III that attenuated diabetic renal injuries.