Circulating uromodulin inhibits vascular calcification by interfering with pro-inflammatory cytokine signalling

Abstract

Aims Uromodulin is produced exclusively in the kidney and secreted into both urine and blood. Serum levels of uromodulin are correlated with kidney function and reduced in chronic kidney disease (CKD) patients, but physiological functions of serum uromodulin are still elusive. This study investigated the role of uromodulin in medial vascular calcification, a key factor associated with cardiovascular events and mortality in CKD patients. Methods and results Experiments were performed in primary human (HAoSMCs) and mouse (MOVAS) aortic smooth muscle cells, cholecalciferol overload and subtotal nephrectomy mouse models and serum from CKD patients. In three independent cohorts of CKD patients, serum uromodulin concentrations were inversely correlated with serum calcification propensity. Uromodulin supplementation reduced phosphate-induced osteo-/chondrogenic transdifferentiation and calcification of HAoSMCs. In human serum, pro-inflammatory cytokines tumour necrosis factor α (TNFα) and interleukin-1β (IL-1β) co-immunoprecipitated with uromodulin. Uromodulin inhibited TNFα and IL-1β-induced osteo-/chondrogenic signalling and activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated β cells (NF-kB) as well as phosphate-induced NF-kB-dependent transcriptional activity in HAoSMCs. In vivo, adeno-associated virus (AAV)-mediated overexpression of uromodulin ameliorated vascular calcification in mice with cholecalciferol overload. Conversely, cholecalciferol overload-induced vascular calcification was aggravated in uromodulin-deficient mice. In contrast, uromodulin overexpression failed to reduce vascular calcification during renal failure in mice. Carbamylated uromodulin was detected in serum of CKD patients and uromodulin carbamylation inhibited its anti-calcific properties in vitro. Conclusions Uromodulin counteracts vascular osteo-/chondrogenic transdifferentiation and calcification, at least in part, through interference with cytokine-dependent pro-calcific signalling. In CKD, reduction and carbamylation of uromodulin may contribute to vascular pathology.

Hyperphosphatemia and Cardiovascular Disease

“…• Up-regulate the expression of pit (Shobeiri et al, 2014) • Up-regulate osteogenic transcription of VSMCs (Singh et al, 2019;Voelkl et al, 2019;Bao et al, 2020;Chang et al, 2020;Takashi and Fukumoto, 2020b) • Pro-inflammatory cytokines (Voelkl et al, 2019;Alesutan et al, 2020) • Apoptosis and autophagy (Shroff et al, 2008;Liu et al, 2017;Ciceri et al, 2019;Voelkl et al, 2019) • Reduction of fetuin-A (Voelkl et al, 2019) • Remodeling of extracellular matrix (Voelkl et al, 2019) • Oxidative stress (Voelkl et al, 2019) • α-klotho deficiency (Singh et al, 2019)…”

“…Pro-inflammatory cytokines are a class of endogenous peptides mainly produced by immune cells, including interleukin (IL) -1β, tumor necrosis factor (TNF) – α, IL-6. In vitro studies showed that IL-1β and TNF-α could stimulate the intracellular NF-κB signaling, and IL-6 activates BMP-2-wnt/β-Catenin pathway to induce the calcification of vascular smooth muscle cells ( Voelkl et al, 2019 ; Alesutan et al, 2020 ). Increased FGF-23 levels and pro-inflammatory cytokines were found in patients with hyperphosphatemia ( Mendoza et al, 2017 ).…”

<p>Presepsin Level Correlates with the Development of Moderate Coronary Artery Calcifications in Hemodialysis Patients: A Preliminary Cross-Section Design Study</p>

“…This enhancement, however, may also be related to the existing inflammation just before the initiation of HD. 18,28 It must be mentioned that mineral metabolism alteration plays an essential role in VC and also induces microinflammation. 29 When HD is initiated, several calcification factors evolve.…”

“…CRP is an acute phase reactant produced from hepatocytes following an increase in proinflammatory cytokines. 22,28 Presepsin, on the other hand, is a marker of activated monocytes/macrophages and probably of circulating calcifying cells of myeloid origin in CKD patients, 11 therefore, higher presepsin would be a better inflammatory predictor in CAC development.…”

The kidney releases a non-polymerizing form of Uromodulin in the urine and circulation that retains the external hydrophobic patch domain

“…In the renal interstitium, THP affects multiple cell types, such as S3 proximal tubules, where it inhibits pro-inflammatory signaling (20, 21), and immune cells, where it regulates the abundance and phagocytic activity of resident mononuclear phagocytes (MPCs) and protects against inflammation following kidney injury (22). THP has also important systemic effects on other organs, such as regulation of granulopoiesis, vascular calcification and mitigation of oxidative stress through inhibition of the TRPM2 channel (23-25). Many studies have evaluated the role of both serum and urinary THP as biomarkers.…”