scholarly journals Senescence marker activin A is increased in human diabetic kidney disease: association with kidney function and potential implications for therapy

2019 ◽  
Vol 7 (1) ◽  
pp. e000720 ◽  
Author(s):  
Xiaohui Bian ◽  
Tomás P Griffin ◽  
Xiangyang Zhu ◽  
Md Nahidul Islam ◽  
Sabena M Conley ◽  
...  

ObjectiveActivin A, an inflammatory mediator implicated in cellular senescence-induced adipose tissue dysfunction and profibrotic kidney injury, may become a new target for the treatment of diabetic kidney disease (DKD) and chronic kidney diseases. We tested the hypothesis that human DKD-related injury leads to upregulation of activin A in blood and urine and in a human kidney cell model. We further hypothesized that circulating activin A parallels kidney injury markers in DKD.Research design and methodsIn two adult diabetes cohorts and controls (Minnesota, USA; Galway, Ireland), the relationships between plasma (or urine) activin A, estimated glomerular filtration rate (eGFR) and DKD injury biomarkers were tested with logistic regression and correlation coefficients. Activin A, inflammatory, epithelial-mesenchymal-transition (EMT) and senescence markers were assayed in human kidney (HK-2) cells incubated in high glucose plus transforming growth factor-β1 or albumin.ResultsPlasma activin A levels were elevated in diabetes (n=206) compared with controls (n=76; 418.1 vs 259.3 pg/mL; p<0.001) and correlated inversely with eGFR (rs=−0.61; p<0.001; diabetes). After eGFR adjustment, only albuminuria (OR 1.56, 95% CI 1.16 to 2.09) and tumor necrosis factor receptor-1 (OR 6.40, 95% CI 1.08 to 38.00) associated with the highest activin tertile. Albuminuria also related to urinary activin (rs=0.65; p<0.001). Following in vitro HK-2 injury, activin, inflammatory, EMT genes and supernatant activin levels were increased.ConclusionsCirculating activin A is increased in human DKD and correlates with reduced kidney function and kidney injury markers. DKD-injured human renal tubule cells develop a profibrotic and inflammatory phenotype with activin A upregulation. These findings underscore the role of inflammation and provide a basis for further exploration of activin A as a diagnostic marker and therapeutic target in DKD.

2021 ◽  
Vol 9 (1) ◽  
pp. e002038
Author(s):  
Yang Li ◽  
Meng Xue ◽  
Fang Hu ◽  
Yijie Jia ◽  
Zongji Zheng ◽  
...  

IntroductionAs a key event leading to tubulointerstitial fibrosis in diabetic kidney disease (DKD), epithelial–mesenchymal transition (EMT) has drawn increasing attention from researchers. The antiaging protein Klotho attenuates renal fibrosis in part by inhibiting ERK1/2 signaling in DKD. Early growth response factor 1 (Egr-1), which is activated mainly by ERK1/2, has been shown to play an important role in EMT. However, whether Klotho prevents EMT by inhibiting ERK1/2-dependent Egr-1 expression in DKD is unclear.The aim of this study was to investigate whether Klotho prevents EMT through Egr-1 downregulation by inhibiting the ERK1/2 signaling pathway in DKD.Research design and methodsMale C57BL/6J mice fed an high-fat diet for 4 weeks received 120 mg/kg streptozotocin (STZ), which was injected intraperitoneally. Klotho and Egr-1 expression was detected in the renal cortices of these mice on their sacrifice at 6 and 12 weeks after STZ treatment. In In vitro studies, we incubated HK2 cells under high-glucose (HG) or transforming growth factor-β1 (TGF-β1) conditions to mimic DKD. We then transfected the cells with an Klotho-containing plasmid, Klotho small interfering RNA.ResultsKlotho expression was significantly decreased in the renal cortices of mice with diabetes mellitus (DM) compared with the renal cortices of control mice at 6 weeks after treatment and even more significantly decreased at 12 weeks. In contrast, Egr-1 expression was significantly increased in mice with DM compared with control mice only at 12 weeks. We also found that Klotho overexpression downregulated Egr-1 expression and the (p-ERK1/2):(ERK1/2) ratio in HG-treated or TGF-β1-treated HK2 cells. Conversely, Klotho silencing upregulated Egr-1 expression and the (p-ERK1/2):(ERK1/2) ratio in HG-treated or TGF-β1-treated HK2 cells. Moreover, the effects of si-Klotho were abolished by the ERK1/2 inhibitor PD98059.ConclusionsKlotho prevents EMT during DKD progression, an effect that has been partially attributed to Egr-1 downregulation mediated by ERK1/2 signaling pathway inhibition.


Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 504
Author(s):  
Stefanos Roumeliotis ◽  
Panagiotis I. Georgianos ◽  
Athanasios Roumeliotis ◽  
Theodoros Eleftheriadis ◽  
Aikaterini Stamou ◽  
...  

Proteinuria is characterized by low accuracy for predicting onset and development of diabetic kidney disease (DKD) because it is not directly associated with molecular changes that promote DKD, but is a result of kidney damage. Oxidized low-density lipoprotein (ox-LDL) reflects oxidative stress and endothelial dysfunction, both underlying the development of proteinuria and loss of kidney function in DKD. We aimed to investigate whether ox-LDL modifies the association between proteinuria and progression of DKD in a cohort of 91 patients with proteinuric DKD and diabetic retinopathy, followed for 10 years. The primary endpoint was a combined kidney outcome of eGFR decline ≥30% or progression to end-stage kidney disease. After the end of the study, we considered the percentage change of eGFR over time as our secondary outcome. Proteinuria was associated with both outcomes, and ox-LDL amplified the magnitude of this link (p < 0.0001 for primary and p < 0.0001 for secondary outcome, respectively). After adjustment for duration of diabetes, history of cardiovascular disease and serum albumin, ox-LDL remained a significant effect modifier of the association between proteinuria and eGFR decline over time (p = 0.04). Our study shows that in proteinuric DKD, circulating ox-LDL levels amplified the magnitude of the association between proteinuria and progression of DKD.


2021 ◽  
Vol 22 (14) ◽  
pp. 7642
Author(s):  
Zoran V. Popovic ◽  
Felix Bestvater ◽  
Damir Krunic ◽  
Bernhard K. Krämer ◽  
Raoul Bergner ◽  
...  

The CD73 pathway is an important anti-inflammatory mechanism in various disease settings. Observations in mouse models suggested that CD73 might have a protective role in kidney damage; however, no direct evidence of its role in human kidney disease has been described to date. Here, we hypothesized that podocyte injury in human kidney diseases alters CD73 expression that may facilitate the diagnosis of podocytopathies. We assessed the expression of CD73 and one of its functionally important targets, the C-C chemokine receptor type 2 (CCR2), in podocytes from kidney biopsies of 39 patients with podocytopathy (including focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), membranous glomerulonephritis (MGN) and amyloidosis) and a control group. Podocyte CD73 expression in each of the disease groups was significantly increased in comparison to controls (p < 0.001–p < 0.0001). Moreover, there was a marked negative correlation between CD73 and CCR2 expression, as confirmed by immunohistochemistry and immunofluorescence (Pearson r = −0.5068, p = 0.0031; Pearson r = −0.4705, p = 0.0313, respectively), thus suggesting a protective role of CD73 in kidney injury. Finally, we identify CD73 as a novel potential diagnostic marker of human podocytopathies, particularly of MCD that has been notorious for the lack of pathological features recognizable by light microscopy and immunohistochemistry.


2021 ◽  
Vol 22 (4) ◽  
pp. 1525
Author(s):  
Chunling Huang ◽  
Ji Bian ◽  
Qinghua Cao ◽  
Xin-Ming Chen ◽  
Carol A. Pollock

Mitochondria are critical organelles that play a key role in cellular metabolism, survival, and homeostasis. Mitochondrial dysfunction has been implicated in the pathogenesis of diabetic kidney disease. The function of mitochondria is critically regulated by several mitochondrial protein kinases, including the phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1). The focus of PINK1 research has been centered on neuronal diseases. Recent studies have revealed a close link between PINK1 and many other diseases including kidney diseases. This review will provide a concise summary of PINK1 and its regulation of mitochondrial function in health and disease. The physiological role of PINK1 in the major cells involved in diabetic kidney disease including proximal tubular cells and podocytes will also be summarized. Collectively, these studies suggested that targeting PINK1 may offer a promising alternative for the treatment of diabetic kidney disease.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Jan Wysocki ◽  
Minghao Ye ◽  
Ahmed M Khattab ◽  
Yashpal Kanwar ◽  
Mark Osborn ◽  
...  

ACE2 is a monocarboxypeptidase that by converting AngII to Ang1-7 should down-regulate the renin-angiotensin system and therefore provide a means to therapeutically target diabetic kidney disease, a condition where the kidney RAS is overactive. Previous work indicated that soluble human recombinant (r)ACE2 administration for 4 weeks attenuated kidney injury in diabetic Akita mice. Whether such effect of rACE2 can be confirmed and attributed to augmented ACE2 activity is uncertain because chronic use of human rACE2 in mice induces immunogenicity and the development of antibodies that neutralize serum ACE2 activity. To examine the effect of chronic amplification of circulating ACE2 on kidney injury caused by STZ-induced diabetes and to circumvent the immunogenicity arising from xenogeneic ACE2, ACE2 of mouse origin was administered to mice using either daily i.p. injections (1 mg/kg) of mrACE2 for 4 weeks or after 20 weeks of ACE2 mini-circle (MC) (10-30ug/mouse) administration. MC provides a form of gene delivery that is resistant to gene silencing and, in addition, greatly optimizes long-term in vivo overexpression of proteins of interest. ACE2MC resulted in a profound and sustained increase in serum ACE2 activity (2.4±0.3 vs. 497±135 RFU/ul/hr, p<0.01) but kidney ACE2 activity was unchanged (17.4±1.3 vs. 19.0±0.8 RFU/ug prot/hr). mACE2-treated mice injected with STZ developed diabetes similar to sham mice injected with STZ. Systolic BP was not different between non-diabetic mice, sham STZ-mice, and STZ-mice receiving mACE2 by either i.p. mrACE2 or ACE2MC. Urinary albumin was similarly increased in sham STZ-mice and in STZ-mice receiving mACE2. Glomerular mesangial score and glomerular cellularity were both increased to a similar extent in sham STZ-mice and in STZ-mice with mACE2 administration, as compared to non-diabetic controls. In conclusion, profound and long-term augmentation of ACE2 activity confined to the circulation is not sufficient to attenuate glomerular pathology and albuminuria in STZ-induced diabetic kidney disease probably because of lack of kidney delivery of ACE2. Strategies to achieve over-expression of ACE2 at the kidney level are needed to demonstrate a beneficial effect of this enzyme on diabetic kidney disease.


2019 ◽  
Vol 95 (1) ◽  
pp. 178-187 ◽  
Author(s):  
Guozhi Jiang ◽  
Andrea On Yan Luk ◽  
Claudia Ha Ting Tam ◽  
Fangying Xie ◽  
Bendix Carstensen ◽  
...  

2021 ◽  
Vol 1 (1) ◽  
pp. 15-26
Author(s):  
Devang M. Patel ◽  
Yuxin Yang ◽  
Kexin Shi ◽  
Tieqiao Wu ◽  
Mark E. Cooper ◽  
...  

Abstract Diabetes is a noncommunicable disease and arguably represents the greatest pandemic in human history. Diabetic kidney disease (DKD) is seen in both type 1 and type 2 diabetes and can be detected in up to 30–50% of diabetic subjects. DKD is a progressive chronic kidney disease (CKD) and is a leading cause of mortality and morbidity in patients with diabetes. Renal fibrosis and inflammation are the major pathological features of DKD. There are a large number of independent and overlapping profibrotic and pro-inflammatory pathways involved in the pathogenesis and progression of DKD. Among these pathways, the transforming growth factor-β (TGF-β) pathway plays a key pathological role by promoting fibrosis. Sirtuin-1 (SIRT1) is a protein deacetylase that has been shown to be renoprotective with an anti-inflammatory effect. It is postulated that a reduction in renal SIRT1 levels could play a key role in the pathogenesis of DKD and that restoration of SIRT1 will attenuate DKD. Cell division autoantigen 1 (CDA1) synergistically enhances the profibrotic effect of TGF-β in DKD by regulating the expression of the TGF-β type I receptor (TβRI). CDA1 has also been found to be an inhibitor of SIRT1 in the DNA damage response. Indeed, targeting CDA1 in experimental DKD not only attenuates diabetes-associated renal fibrosis but also attenuates the expression of key pro-inflammatory genes such as tumor necrosis factor-α (TNF-α) and Monocyte Che moattractant Protein-1 (MCP-1). In conclusion, there is a large body of experimental data to support the view that targeting CDA1 is a superior approach to directly targeting TGF-β in DKD since it is not only safe but also efficacious in retarding both fibrosis and inflammation.


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