Nephrologies
Abstract
T cells play an important role in acute kidney injury (AKI). Metabolic programming of T cells regulates their function, is a rapidly emerging field, and is unknown in AKI. We induced ischemic AKI in C57B6 mice and collected kidneys and spleens at multiple time points. T cells were isolated and analyzed by an immune-metabolic assay. Unbiased machine learning analyses identified a distinct T cell subset with reduced VDAC1 and mTOR expression in post-AKI kidneys. Ischemic kidneys showed higher expression of trimethylation of histone H3 lysine 27 (H3K27Me3) and glutaminase. Splenic T cells from post-AKI mice had higher expression of GLUT1, hexokinase II, and CPT1a. Human nonischemic and ischemic kidney tissue displayed similar findings to mouse kidneys. Given a convergent role for glutamine in T cell metabolic pathways and the availability of a relatively safe glutamine antagonist JHU083, effects on AKI were evaluated. JHU083 attenuated renal injury and reduced T cell activation and proliferation in ischemic and nephrotoxic AKI, whereas T cell-deficient mice were not protected by glutamine blockade. In vitro hypoxia demonstrated upregulation of glycolysis-related enzymes. T cells undergo metabolic reprogramming during AKI, and reconstitution of metabolism by targeting T cell glutamine pathway could be a promising novel therapeutic approach.
Authors
Kyungho Lee, Elizabeth A. Thompson, Sepideh Gharaie, Chirag H. Patel, Johanna T. Kurzhagen, Phillip M. Pierorazio, Lois J. Arend, Ajit G. Thomas, Sanjeev Noel, Barbara S. Slusher, Hamid Rabb
Abstract
BACKGROUND. Current studies suggest mitochondrial dysfunction is a major contributor to impaired physical performance and exercise intolerance in chronic kidney disease (CKD). We conducted a clinical trial of coenzyme Q10 (CoQ10) and nicotinamide riboside (NR) to determine their impact on exercise tolerance and metabolic profile in CKD patients. METHODS. We conducted a randomized placebo-controlled, double blind, cross-over trial comparing CoQ10, NR, and placebo in 25 patients with eGFR of <60ml/min/1.73m2. Subjects received NR (1000 mg/day), CoQ10 (1200 mg/day), or placebo for 6 weeks each. Primary outcomes were aerobic capacity (VO2 peak) and work efficiency measured using graded cycle ergometry testing. We performed semi-targeted plasma metabolomics and lipidomics. RESUTS. Participant mean age was 61.0 ± 11.6 years and mean eGFR was 36.9±9.2 ml/min/1.73m2. Compared to placebo, we found no differences in VO2 peak (P=0.30, 0.17), total work (P=0.47, 0.77), and total work efficiency (P=0.46, 0.55) post NR or CoQ10 supplementation. NR decreased submaximal VO2 at 30W (P=0.03) and VO2 at 60W (P=0.07) compared to placebo. No changes in eGFR were observed post-NR or CoQ10 (P=0.14, 0.88). CoQ10 increased free fatty acids and decreased complex medium/long chain triglycerides. NR supplementation significantly altered TCA cycle intermediates and glutamate that are involved in reactions that exclusively use NAD+ and NADP+ as cofactors. NR decreased a broad range of lipid groups including triglycerides and ceramides. CONCLUSIONS. Six-weeks of treatment with NR or CoQ10 improved markers of systemic mitochondrial metabolism and lipid profiles but did not improve VO2 peak or total work efficiency. TRIAL REGISTRATION. ClinicalTrials.gov (NCT03579693) FUNDING. This study was supported by National Institutes of Diabetes and Digestive Kidney Diseases R01 DK101509 (to BK), R03 DK114502 (to BR), R01 DK125794 (to BR), R01 DK101509 (to JG), Dialysis Clinics Incorporated C-4112 (to BR), Northern California VA Health Care System (BR).
Authors
Armin Ahmadi, Gwenaelle Begue, Ana P. Valencia, Jennifer E. Norman, Benjamin Lidgard, Brian J. Bennett, Matthew P. Van Doren, David J. Marcinek, Sili Fan, David K. Prince, Jorge L. Gamboa, Jonathan Himmelfarb, Ian H. de Boer, Bryan R. Kestenbaum, Baback Roshanravan
Abstract
Viral illnesses like SARS-CoV-2 have pathologic effects on non-respiratory organs in the absence of direct viral infection. We injected mice with cocktails of rodent equivalents of human cytokine storms resulting from SARS-CoV-2 / COVID-19 or Rhinovirus common cold infection. At low doses, COVID-19 cocktails induced glomerular injury and albuminuria in Zhx2 hypomorph and Zhx2+/+ mice to mimic COVID-19 related proteinuria. Common Cold cocktail induced albuminuria selectively in Zhx2 hypomorph mice to model relapse of Minimal Change Disease (MCD), that improved after depletion of TNF-α or sIL-4Rα or IL-6. The Zhx2 hypomorph state increased cell membrane to nuclear migration of podocyte ZHX proteins in vivo (both cocktails) and lowered pSTAT6 activation (COVID-19 cocktail) in vitro. At higher doses, COVID-19 cocktails induced acute heart injury, myocarditis, pericarditis, acute liver injury and acute kidney injury, and high mortality in Zhx2+/+ mice, whereas Zhx2 hypomorph mice were relatively protected, due in part to early asynchronous activation of STAT5 and STAT6 pathways in these organs. Dual depletion of cytokine combinations of TNF-α with IL-2 or IL-13 or IL-4 in Zhx2+/+ mice reduced multiorgan injury and eliminated mortality. Using genome sequencing and CRISPR-Cas9, an insertion upstream of ZHX2 was identified as a cause of the human ZHX2 hypomorph state.
Authors
Maria Del Nogal Avila, Ranjan Das, Joubert B. Kharlyngdoh, Eduardo Molina-Jijon, Hector Donoro-Blazquez, Stéphanie Gambut, Michael R. Crowley, David K. Crossman, Rasheed A. Gbadagesin, Sunveer S. Chugh, Sunjeet S. Chugh, Carmen Avila-Casado, Camille Macé, Lionel C. Clement, Sumant S. Chugh
Abstract
Acute kidney injury (AKI) secondary to sepsis results in poor outcomes and conventional kidney function indicators lack diagnostic value. Soluble urokinase plasminogen activator receptor (suPAR) is an innate immune–derived molecule implicated in inflammatory organ damage. We characterized the diagnostic ability of longitudinal serum suPAR levels to discriminate severity and course of sepsis-induced AKI (SI-AKI) in 200 critically ill patients meeting Sepsis-3 criteria. The pathophysiologic relevance of varying suPAR levels in SI-AKI was explored in a polymicrobial sepsis model in WT, (s)uPAR-knockout, and transgenic suPAR-overexpressing mice. At all time points studied, suPAR provided a robust classification of SI-AKI disease severity, with improved prediction of renal replacement therapy (RRT) and mortality compared with established kidney biomarkers. Patients with suPAR levels of greater than 12.7 ng/mL were at highest risk for RRT or death, with an adjusted odds ratio of 7.48 (95% CI, 3.00–18.63). suPAR deficiency protected mice against SI-AKI. suPAR-overexpressing mice exhibited greater kidney damage and poorer survival through inflamed kidneys, accompanied by local upregulation of potent chemoattractants and pronounced kidney T cell infiltration. Hence, suPAR allows for an innate immune–derived and kidney function–independent staging of SI-AKI and offers improved longitudinal risk stratification. suPAR promotes T cell–based kidney inflammation, while suPAR deficiency improves SI-AKI.
Authors
Christian Nusshag, Changli Wei, Eunsil Hahm, Salim S. Hayek, Jing Li, Beata Samelko, Christoph Rupp, Roman Szudarek, Claudius Speer, Florian Kälble, Matthias Schaier, Florian Uhle, Felix C.F. Schmitt, Mascha O. Fiedler, Ellen Krautkrämer, Yanxia Cao, Ricardo Rodriguez, Uta Merle, Jesper Eugen-Olsen, Martin Zeier, Markus A. Weigand, Christian Morath, Thorsten Brenner, Jochen Reiser
Abstract
BACKGROUND. Longitudinal investigations of murine acute kidney injury (AKI) suggest that injury and inflammation may persist long after the initial insult. However, the evolution of these processes and their prognostic values are unknown in patients with AKI. METHODS. In a prospective cohort of 656 participants hospitalized with AKI, we measured seven urine and two plasma biomarkers of kidney injury, inflammation, and tubular health at multiple timepoints from the diagnosis to 12 months after AKI. We used linear mixed-effect models to estimate biomarker changes over time, and used Cox proportional hazard regressions to determine their associations with a composite outcome of CKD incidence and progression. We compared the gene expression kinetics of biomarkers in murine models of repair and atrophy after ischemic reperfusion injury (IRI). RESULTS. After 4.3 years, 106 and 52 participants developed incident CKD and CKD progression, respectively. Each standard deviation increases in the change of urine KIM-1, MCP-1 and plasma TNFR1 from baseline to 12 months was associated with 2-3-fold increased risk for CKD, while the increase in urine UMOD was associated with 40% reduced risk for CKD. The trajectories of these biological processes were associated with progression to kidney atrophy in mice after IRI. CONCLUSION. Sustained tissue injury and inflammation, and slower restoration of tubular health are associated with higher risk of kidney disease progression. Further investigation into these ongoing biological processes may help understand and prevent the AKI-to-CKD transition. FUNDING. NIH and NIDDK (grants U01DK082223, U01DK082185, U01DK082192, U01DK082183, R01DK098233, R01DK101507, R01DK114014, K23DK100468, R03DK111881, K01DK120783, and R01DK093771).
Authors
Yumeng Wen, Leyuan Xu, Isabel A. Melchinger, Heather Thiessen-Philbrook, Dennis G. Moledina, Steven G. Coca, Chi-yuan Hsu, Alan S. Go, Kathleen D. Liu, Edward D. Siew, T. Alp Ikizler, Vernon M. Chinchilli, James S. Kaufman, Paul L. Kimmel, Jonathan Himmelfarb, Lloyd G. Cantley, Chirag R. Parikh
Abstract
Cisplatin is a widely used chemotherapy drug but it induces both acute and chronic kidney diseases (CKD) in cancer patients. The pathogenesis of cisplatin-induced CKD is unclear and effective renoprotective approaches are not available. Here, we report that repeated low-dose cisplatin (RLDC) treatment of C57BL/6 mice induced chronic cellular senescence in kidney tubules, accompanied with tubular degeneration and pro-fibrotic phenotype transformation that culminated in maladaptive repair and renal fibrosis. Suppression of tubular senescence by senolytic drugs ABT-263 and Fisetin attenuated renal fibrosis and improved tubular repair as indicated by restoration of tubular regeneration and renal function. In vitro, RLDC also induced senescence in mouse proximal tubular BUMPT cells. ABT-263 eliminated senescent BUMPT cells following RLDC treatment, reversed the pro-fibrotic phenotype of the cells and increased their clonogenic activity. Moreover, ABT-263 alleviated the paracrine effect of RLDC-treated BUMPT cells on fibroblasts for fibrosis. Consistently, knockdown of p16 suppressed post-RLDC senescence and fibrotic changes in BUMPT cells, and alleviated their paracrine effects on renal fibroblast proliferation. These results indicate that persistent induction of tubular senescence plays an important role in promoting cisplatin-induced CKD. Targeting senescent tubular cells may be efficient to improve kidney repair for the prevention and treatment of cisplatin-induced CKD.
Authors
Siyao Li, Man J. Livingston, Zhengwei Ma, Xiaoru Hu, Lu Wen, Han-Fei Ding, Daohong Zhou, Zheng Dong
Abstract
Despite recent progress in the identification of mediators of podocyte injury, mechanisms underlying podocyte loss remain poorly understood, and cell-specific therapy is lacking. We previously reported that KIBRA, KIdney and BRAin expressed protein, encoded by WWC1, promotes podocyte injury in vitro through activation of the Hippo signaling pathway. KIBRA expression is increased in the glomeruli of patients with focal segmental glomerulosclerosis (FSGS), and KIBRA depletion in vivo is protective against acute podocyte injury. Here, we tested the consequences of transgenic podocyte-specific WWC1 expression in immortalized human podocytes and in mice, and we explored the association between glomerular WWC1 expression and glomerular disease progression. We found that KIBRA overexpression in immortalized human podocytes promoted cytoplasmic localization of YAP (Yes-associated protein), induced actin cytoskeletal reorganization, and altered focal adhesion expression and morphology. Transgenic WWC1 (KIBRA OE) mice were more susceptible to acute and chronic glomerular injury, with evidence of YAP inhibition in vivo. Of clinical relevance, glomerular WWC1 expression negatively correlated with renal survival among patients with primary glomerular diseases. These findings highlight the importance of KIBRA-YAP signaling to the regulation of podocyte structural integrity and identify KIBRA-mediated injury as a potential target for podocyte-specific therapy in glomerular disease.
Authors
Kristin Meliambro, Yanfeng Yang, Marina de Cos, Estefania Rodriguez-Ballestas, Caroline Malkin, Jonathan C. Haydak, John R. Lee, Fadi Salem, Laura H. Mariani, Ronald E. Gordon, John M. Basgen, Huei Hsun Wen, Jia Fu, Evren U. Azeloglu, John Cijiang He, Jenny S. Wong, Kirk N. Campbell
Abstract
We examine whether calcineurin or protein-phosphatase-2B (PP2B) regulates the basolateral Kir4.1/Kir5.1 in distal-convoluted-tubule (DCT). Application of tacrolimus (FK506) or cyclosporine-A (CsA) increased whole-cell-Kir4.1/Kir5.1-mediated-K+-currents and hyperpolarized DCT-membrane. Moreover, FK506-induced-stimulation of Kir4.1/Kir5.1 was absent in kidney-tubule-specific 12-kDa-FK506-binding-protein knockout-mice (Ks-FKBP-12-KO). In contrast, CsA still stimulated Kir4.1/Kir5.1 of the DCT in Ks-FKBP-12-KO mice, suggesting that FK506-induced stimulation of Kir4.1/Kir5.1 was due to inhibiting PP2B. Single-channel-patch-clamp experiments demonstrated that FK506 or CsA stimulated the basolateral Kir4.1/Kir5.1-activity of DCT, defined by NPo (a product of channel-Number- and- Open-Probability). However, this effect was absent in the DCT treated with Src-family-protein-tyrosine-kinase (SFK) inhibitor or hydroxyl-peroxide which stimulates SFK. Fluorescence-image demonstrated that CsA-treatment increased membrane-staining-intensity of Kir4.1 in the DCT of Kcnj10flox/flox mice. Moreover, CsA-treatment has no obvious effect on pNCC expression in Ks-Kir4.1-KO mice. Immunoblotting showed that acute FK506 treatment increased pNCC-expression in Kcnj10flox/flox mice, but this effect was attenuated in Ks-Kir4.1-KO mice. In vivo measurement of thiazide-induced-renal-Na+ excretion demonstrated that FK506 enhanced thiazide-induced natriuresis. This effect was absent in Ks-FKBP-12-KO mice and blunted in Ks-Kir4.1-KO mice. We conclude that inhibition of PP2B stimulates Kir4.1/Kir5.1 of DCT and NCC, and that PP2B-inhibition-induced stimulation of NCC is partially achieved by stimulation of the basolateral Kir4.1/Kir5.1.
Authors
Dan-Dan Zhang, Xin-Peng Duan, Kerim Mutig, Franziska Rausch, Yu Xiao, Jun-Ya Zheng, Dao-Hong Lin, Wen-Hui Wang
Abstract
The transcription factor c-Maf has been widely studied and has been reported to play a critical role in embryonic kidney development; however, the postnatal functions of c-Maf in adult kidneys remain unknown as c-Maf null C57BL/6J mice exhibit embryonic lethality. In this study, we investigated the role of c-Maf in adult mouse kidneys by comparing the phenotypes of tamoxifen (TAM)-inducible c-Maf knockout mice (c-Maf flox/flox; CAG-Cre-ERTM mice named “c-Maf ΔTAM”) with c-Maf flox/flox control mice10 days after TAM injection (TAM(10d)). In addition, we examined the effects of c-Maf deletion on diabetic conditions by injecting the mice with streptozotocin (STZ) four weeks before TAM injection. c-Maf ΔTAM mice displayed primary glycosuria caused by Sglt2 and Glut2 downregulation in the kidneys without diabetes, as well as morphological changes and life-threatening injuries in the kidneys on TAM(10d). Under diabetic conditions, c-Maf deletion promoted recovery from hyperglycemia and suppressed albuminuria and diabetic nephropathy by causing similar effects to Sglt2 knockout and SGLT2 inhibitors. In addition to demonstrating the unique gene regulation of c-Maf, these findings highlight the renoprotective effects of c-Maf deficiency under diabetic conditions and suggest that c-Maf could be a novel therapeutic target gene for treating diabetic nephropathy.
Authors
Mitsunori Fujino, Naoki Morito, Takuto Hayashi, Masami Ojima, Shun Ishibashi, Akihiro Kuno, Seizo Koshiba, Kunihiro Yamagata, Satoru Takahashi
Abstract
Acute kidney failure and chronic kidney disease are global health issues steadily rising in incidence and prevalence. Animal models on a single genetic background have so far failed to recapitulate the clinical presentation of human nephropathies. Here, we used a simple model of folic acid–induced kidney injury in 7 highly diverse mouse strains. We measured plasma and urine parameters, as well as renal histopathology and mRNA expression data, at 1, 2, and 6 weeks after injury, covering the early recovery and long-term remission. We observed an extensive strain-specific response ranging from complete resistance of the CAST/EiJ to high sensitivity of the C57BL/6J, DBA/2J, and PWK/PhJ strains. In susceptible strains, the severe early kidney injury was accompanied by the induction of mitochondrial stress response (MSR) genes and the attenuation of NAD+ synthesis pathways. This is associated with delayed healing and a prolonged inflammatory and adaptive immune response 6 weeks after insult, heralding a transition to chronic kidney disease. Through a thorough comparison of the transcriptomic response in mouse and human disease, we show that critical metabolic gene alterations were shared across species, and we highlight the PWK/PhJ strain as an emergent model of transition from acute kidney injury to chronic disease.
Authors
Jean-David Morel, Maroun Bou Sleiman, Terytty Yang Li, Giacomo von Alvensleben, Alexis M. Bachmann, Dina Hofer, Ellen Broeckx, Jing Ying Ma, Vinicius Carreira, Tao Chen, Nabil Azhar, Romer A. Gonzalez-Villalobos, Matthew Breyer, Dermot Reilly, Shannon Mullican, Johan Auwerx
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