WNT/β-catenin signaling promotes VSMCs to osteogenic transdifferentiation and calcification through directly modulating Runx2 gene expression

AbstractArterial medial calcification (AMC) is prevalent in patients with chronic kidney disease (CKD) and contributes to elevated risk of cardiovascular events and mortality. Vascular smooth muscle cells (VSMCs) to osteogenic transdifferentiation (VOT) in a high-phosphate environment is involved in the pathogenesis of AMC in CKD. WNT/β-catenin signaling is indicated to play a crucial role in osteogenesis via promoting Runx2 expression in osteoprogenitor cells, however, its role in Runx2 regulation and VOT remains incompletely clarified. In this study, Runx2 was induced and β-catenin was activated by high-phosphate in VSMCs. Two forms of active β-catenin, dephosphorylated on Ser37/Thr41 and phosphorylated on Ser675 sites, were upregulated by high-phosphate. Activation of β-catenin, through ectopic expression of stabilized β-catenin, inhibition of GSK-3β, or WNT-3A protein, induced Runx2 expression, whereas blockade of WNT/β-catenin signaling with Porcupine (PORCN) inhibitor or Dickkopf-1 (DKK1) protein inhibited Runx2 induction by high-phosphate. WNT-3A promoted osteocalcin expression and calcium deposition in VSMCs, whereas DKK1 ameliorated calcification of VSMCs induced by high-phosphate. Two functional T cell factor (TCF)/lymphoid enhancer-binding factor binding sites were identified in the promoter region of Runx2 gene in VSMCs, which interacted with TCF upon β-catenin activation. Site-directed mutation of each of them attenuated Runx2 response to β-catenin, and deletion or destruction of both of them completely abolished this responsiveness. In the aortic tunica media of rats with chronic renal failure, followed by AMC, Runx2 and β-catenin was induced, and the Runx2 mRNA level was positively associated with the abundance of phosphorylated β-catenin (Ser675). Collectively, our study suggested that high-phosphate may activate WNT/β-catenin signaling through different pathways, and the activated WNT/β-catenin signaling, through direct downstream target Runx2, could play an important role in promoting VOT and AMC

An international Delphi consensus statement on metabolic dysfunction-associated fatty liver disease and risk of chronic kidney disease

Background: With the rising global prevalence of fatty liver disease related to metabolic dysfunction, the association of this common liver condition with chronic kidney disease (CKD) has become increasingly evident. In 2020, the more inclusive term metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed to replace the term non-alcoholic fatty liver disease (NAFLD). The observed association between MAFLD and CKD and our understanding that CKD can be a consequence of underlying metabolic dysfunction support the notion that individuals with MAFLD are at higher risk of having and developing CKD compared with those without MAFLD. However, to date, there is no appropriate guidance on CKD in individuals with MAFLD. Furthermore, there has been little attention paid to the link between MAFLD and CKD in the Nephrology community. Methods and Results: Using a Delphi-based approach, a multidisciplinary panel of 50 international experts from 26 countries reached a consensus on some of the open research questions regarding the link between MAFLD and CKD. Conclusions: This Delphi-based consensus statement provided guidance on the epidemiology, mechanisms, management and treatment of MAFLD and CKD, as well as the relationship between the severity of MAFLD and risk of CKD, which establish a framework for the early prevention and management of these two common and interconnected diseases.Fil: Sun, Dan Qin. Jiangnan University Medical Center; China. Nantong University; ChinaFil: Targher, Giovanni. Azienda Ospedaliera Universitaria Integrata Verona; ItaliaFil: Byrne, Christopher D.. University of Southampton; Reino UnidoFil: Wheeler, David C.. University College London; Estados UnidosFil: Wong, Vincent Wai Sun. Chinese University of Hong Kong; ChinaFil: Fan, Jian Gao. Shanghai Jiao Tong University; ChinaFil: Tilg, Herbert. Medical University Innsbruck; AustriaFil: Yuan, Wei Jie. Shanghai Jiao Tong University; ChinaFil: Wanner, Christoph. Würzburg University Clinic; AlemaniaFil: Gao, Xin. Fudan University; ChinaFil: Long, Michelle T.. Boston University School of Medicine; Estados UnidosFil: Kanbay, Mehmet. Koc University School of Medicine; TurquíaFil: Nguyen, Mindie H.. Stanford University Medical Center; Estados UnidosFil: Navaneethan, Sankar D.. Baylor College of Medicine; Estados UnidosFil: Yilmaz, Yusuf. Marmara University; Turquía. Recep Tayyip Erdoğan University; TurquíaFil: Huang, Yuli. Southern Medical University; ChinaFil: Gani, Rino A.. Universitas Indonesia; IndonesiaFil: Marzuillo, Pierluigi. Università della Campania “Luigi Vanvitelli”; ItaliaFil: Boursier, Jérôme. Angers University; FranciaFil: Zhang, Huijie. Southern Medical University; ChinaFil: Jung, Chan Young. Yonsei University; Corea del SurFil: Chai, Jin. Army Medical University; ChinaFil: Valenti, Luca. Università degli Studi di Milano; ItaliaFil: Papatheodoridis, George. Kapodistrian University of Athens; GreciaFil: Sookoian, Silvia Cristina. Centro de Investigacion Traslacional En Salud (cenitres) ; Facultad de Cs. de la Salud ; Universidad Maimonides; . Universidad Abierta Interamericana; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chunsun, Dai. Nanjing Medical University; ChinaFil: Eslam, Mohammed. University of Sydney; AustraliaFil: Wei, Lai. Tsinghua University; ChinaFil: George, Jacob. University of Sydney; AustraliaFil: Zheng, Ming Hua. Wenzhou Medical University; Chin

Uric Acid Induces Renal Inflammation via Activating Tubular NF-κB Signaling Pathway

Inflammation is a pathologic feature of hyperuricemia in clinical settings. However, the underlying mechanism remains unknown. Here, infiltration of T cells and macrophages were significantly increased in hyperuricemia mice kidneys. This infiltration of inflammatory cells was accompanied by an up-regulation of TNF-α, MCP-1 and RANTES expression. Further, infiltration was largely located in tubular interstitial spaces, suggesting a role for tubular cells in hyperuricemia-induced inflammation. In cultured tubular epithelial cells (NRK-52E), uric acid, probably transported via urate transporter, induced TNF-α, MCP-1 and RANTES mRNA as well as RANTES protein expression. Culture media of NRK-52E cells incubated with uric acid showed a chemo-attractive ability to recruit macrophage. Moreover uric acid activated NF-κB signaling. The uric acid-induced up-regulation of RANTES was blocked by SN 50, a specific NF-κB inhibitor. Activation of NF-κB signaling was also observed in tubule of hyperuricemia mice. These results suggest that uric acid induces renal inflammation via activation of NF-κB signaling

An international Delphi consensus statement on metabolic dysfunction-associated fatty liver disease and risk of chronic kidney disease

BACKGROUND: With the rising global prevalence of fatty liver disease related to metabolic dysfunction, the association of this common liver condition with chronic kidney disease (CKD) has become increasingly evident. In 2020, the more inclusive term metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed to replace the term non-alcoholic fatty liver disease (NAFLD). The observed association between MAFLD and CKD and our understanding that CKD can be a consequence of underlying metabolic dysfunction support the notion that individuals with MAFLD are at higher risk of having and developing CKD compared with those without MAFLD. However, to date, there is no appropriate guidance on CKD in individuals with MAFLD. Furthermore, there has been little attention paid to the link between MAFLD and CKD in the Nephrology community. METHODS AND RESULTS: Using a Delphi-based approach, a multidisciplinary panel of 50 international experts from 26 countries reached a consensus on some of the open research questions regarding the link between MAFLD and CKD. CONCLUSIONS: This Delphi-based consensus statement provided guidance on the epidemiology, mechanisms, management and treatment of MAFLD and CKD, as well as the relationship between the severity of MAFLD and risk of CKD, which establish a framework for the early prevention and management of these two common and interconnected diseases

Aristolochic acid causes albuminuria by promoting mitochondrial DNA damage and dysfunction in podocyte.

Aristolochic acid nephropathy, initially found in patients intaking of slimming herbs containing aristolochic acid (AA), was previously considered as a progressive renal interstitial fibrosis and urothelial malignancy. However, the presence of albuminuria in some patients with AAN suggests that AA may also damage the glomerular filtration barrier. In this study, mice AAN model was generated by daily administration of aristolochic acid I sodium salt intraperitoneally at a dose of 6 mg/kg body weight for 3 days. All of the mice developed heavy albuminuria at day 3 and 7 after receiving AA. In the mice received AA, morphologic change of glomeruli was minor under light microscopy but podocyte foot-process effacement was evident under electron microscopy. In mitochondria isolated from kidney, prominent mitochondrial DNA (mtDNA) damage was accompanied with marked decrease of mtDNA copy number and mitochondrial protein expression level. Similar to those in vivo results, AA treatment impaired the filtration barrier function of cultured podocytes. AA promoted mtDNA damage, decreased mtDNA copy number and mitochondrial protein expression in cultured podocytes. In addition, AA treatment also decreased ATP content, oxygen consumption rate and mitochondrial membrane potential as well as increased cellular reactive oxygen species in cultured podocytes. This study highlighted that AA could induce podocyte damage and albuminuria, which may be mediated by promoting mtDNA damage and mitochondrial dysfunction in podocytes