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1.
Front Immunol ; 14: 1230050, 2023.
Article En | MEDLINE | ID: mdl-37744356

Background: The NLRP3 inflammasome integrates several danger signals into the activation of innate immunity and inflammation by secreting IL-1ß and IL-18. Most published data relate to the NLRP3 inflammasome in immune cells, but some reports claim similar roles in parenchymal, namely epithelial, cells. For example, podocytes, epithelial cells critical for the maintenance of kidney filtration, have been reported to express NLRP3 and to release IL-ß in diabetic kidney disease, contributing to filtration barrier dysfunction and kidney injury. We questioned this and hence performed independent verification experiments. Methods: We studied the expression of inflammasome components in human and mouse kidneys and human podocytes using single-cell transcriptome analysis. Human podocytes were exposed to NLRP3 inflammasome agonists in vitro and we induced diabetes in mice with a podocyte-specific expression of the Muckle-Wells variant of NLRP3, leading to overactivation of the Nlrp3 inflammasome (Nphs2Cre;Nlrp3A350V) versus wildtype controls. Phenotype analysis included deep learning-based glomerular and podocyte morphometry, tissue clearing, and STED microscopy of the glomerular filtration barrier. The Nlrp3 inflammasome was blocked by feeding ß-hydroxy-butyrate. Results: Single-cell transcriptome analysis did not support relevant NLRP3 expression in parenchymal cells of the kidney. The same applied to primary human podocytes in which NLRP3 agonists did not induce IL-1ß or IL-18 secretion. Diabetes induced identical glomerulomegaly in wildtype and Nphs2Cre;Nlrp3A350V mice but hyperfiltration-induced podocyte loss was attenuated and podocytes were larger in Nphs2Cre;Nlrp3A350V mice, an effect reversible with feeding the NLRP3 inflammasome antagonist ß-hydroxy-butyrate. Ultrastructural analysis of the slit diaphragm was genotype-independent hence albuminuria was identical. Conclusion: Podocytes express low amounts of the NLRP3 inflammasome, if at all, and do not produce IL-1ß and IL-18, not even upon introduction of the A350V Muckle-Wells NLRP3 variant and upon induction of podocyte stress. NLRP3-mediated glomerular inflammation is limited to immune cells.


Cryopyrin-Associated Periodic Syndromes , Diabetes Mellitus, Experimental , NLR Family, Pyrin Domain-Containing 3 Protein , Podocytes , Animals , Humans , Mice , Butyrates , Epithelial Cells , Inflammasomes , Interleukin-18 , Kidney , NLR Family, Pyrin Domain-Containing 3 Protein/genetics
2.
Bio Protoc ; 13(16): e4757, 2023 Aug 20.
Article En | MEDLINE | ID: mdl-37638296

Kidney diseases are a global health concern. Modeling of kidney disease for translational research is often challenging because of species specificities or the postmitotic status of kidney epithelial cells that make primary cultures, for example podocytes. Here, we report a protocol for preparing primary cultures of podocytes based on the isolation and in vitro propagation of immature kidney progenitor cells subsequently differentiated into mature podocytes. This protocol can be useful for studying physiology and pathophysiology of human kidney progenitors and to obtain differentiated podocytes for modeling podocytopathies and other kidney disorders involving podocytes.

3.
Am J Physiol Cell Physiol ; 325(4): C849-C861, 2023 10 01.
Article En | MEDLINE | ID: mdl-37642236

Polyploidization of tubular cells (TC) is triggered by acute kidney injury (AKI) to allow survival in the early phase after AKI, but in the long run promotes fibrosis and AKI-chronic kidney disease (CKD) transition. The molecular mechanism governing the link between polyploid TC and kidney fibrosis remains to be clarified. In this study, we demonstrate that immediately after AKI, expression of cell cycle markers mostly identifies a population of DNA-damaged polyploid TC. Using transgenic mouse models and single-cell RNA sequencing we show that, unlike diploid TC, polyploid TC accumulate DNA damage and survive, eventually resting in the G1 phase of the cell cycle. In vivo and in vitro single-cell RNA sequencing along with sorting of polyploid TC shows that these cells acquire a profibrotic phenotype culminating in transforming growth factor (TGF)-ß1 expression and that TGF-ß1 directly promotes polyploidization. This demonstrates that TC polyploidization is a self-sustained mechanism. Interactome analysis by single-cell RNA sequencing revealed that TGF-ß1 signaling fosters a reciprocal activation loop among polyploid TC, macrophages, and fibroblasts to sustain kidney fibrosis and promote CKD progression. Collectively, this study contributes to the ongoing revision of the paradigm of kidney tubule response to AKI, supporting the existence of a tubulointerstitial cross talk mediated by TGF-ß1 signaling produced by polyploid TC following DNA damage.NEW & NOTEWORTHY Polyploidization in tubular epithelial cells has been neglected until recently. Here, we showed that polyploidization is a self-sustained mechanism that plays an important role during chronic kidney disease development, proving the existence of a cross talk between infiltrating cells and polyploid tubular cells. This study contributes to the ongoing revision of kidney adaptation to injury, posing polyploid tubular cells at the center of the process.


Acute Kidney Injury , Transforming Growth Factor beta1 , Animals , Mice , Transforming Growth Factor beta1/genetics , Acute Kidney Injury/genetics , Epithelial Cells , Polyploidy , Fibrosis
4.
J Am Soc Nephrol ; 34(9): 1513-1520, 2023 09 01.
Article En | MEDLINE | ID: mdl-37428955

SIGNIFICANCE STATEMENT: We hypothesized that triple therapy with inhibitors of the renin-angiotensin system (RAS), sodium-glucose transporter (SGLT)-2, and the mineralocorticoid receptor (MR) would be superior to dual RAS/SGLT2 blockade in attenuating CKD progression in Col4a3 -deficient mice, a model of Alport syndrome. Late-onset ramipril monotherapy or dual ramipril/empagliflozin therapy attenuated CKD and prolonged overall survival by 2 weeks. Adding the nonsteroidal MR antagonist finerenone extended survival by 4 weeks. Pathomics and RNA sequencing revealed significant protective effects on the tubulointerstitium when adding finerenone to RAS/SGLT2 inhibition. Thus, triple RAS/SGLT2/MR blockade has synergistic effects and might attenuate CKD progression in patients with Alport syndrome and possibly other progressive chronic kidney disorders. BACKGROUND: Dual inhibition of the renin-angiotensin system (RAS) plus sodium-glucose transporter (SGLT)-2 or the mineralocorticoid receptor (MR) demonstrated additive renoprotective effects in large clinical trials. We hypothesized that triple therapy with RAS/SGLT2/MR inhibitors would be superior to dual RAS/SGLT2 blockade in attenuating CKD progression. METHODS: We performed a preclinical randomized controlled trial (PCTE0000266) in Col4a3 -deficient mice with established Alport nephropathy. Treatment was initiated late (age 6 weeks) in mice with elevated serum creatinine and albuminuria and with glomerulosclerosis, interstitial fibrosis, and tubular atrophy. We block-randomized 40 male and 40 female mice to either nil (vehicle) or late-onset food admixes of ramipril monotherapy (10 mg/kg), ramipril plus empagliflozin (30 mg/kg), or ramipril plus empagliflozin plus finerenone (10 mg/kg). Primary end point was mean survival. RESULTS: Mean survival was 63.7±10.0 days (vehicle), 77.3±5.3 days (ramipril), 80.3±11.0 days (dual), and 103.1±20.3 days (triple). Sex did not affect outcome. Histopathology, pathomics, and RNA sequencing revealed that finerenone mainly suppressed the residual interstitial inflammation and fibrosis despite dual RAS/SGLT2 inhibition. CONCLUSION: Experiments in mice suggest that triple RAS/SGLT2/MR blockade may substantially improve renal outcomes in Alport syndrome and possibly other progressive CKDs because of synergistic effects on the glomerular and tubulointerstitial compartments.


Diabetes Mellitus, Type 2 , Nephritis, Hereditary , Renal Insufficiency, Chronic , Animals , Female , Male , Mice , Antihypertensive Agents/therapeutic use , Diabetes Mellitus, Type 2/drug therapy , Fibrosis , Glucose Transport Proteins, Facilitative/pharmacology , Glucose Transport Proteins, Facilitative/therapeutic use , Nephritis, Hereditary/drug therapy , Nephritis, Hereditary/genetics , Nephritis, Hereditary/pathology , Ramipril/therapeutic use , Receptors, Mineralocorticoid , Renal Insufficiency, Chronic/drug therapy , Renin-Angiotensin System , Sodium , Sodium-Glucose Transporter 2/pharmacology , Sodium-Glucose Transporter 2/therapeutic use
5.
Nat Commun ; 13(1): 5805, 2022 10 04.
Article En | MEDLINE | ID: mdl-36195583

Acute kidney injury (AKI) is frequent, often fatal and, for lack of specific therapies, can leave survivors with chronic kidney disease (CKD). We characterize the distribution of tubular cells (TC) undergoing polyploidy along AKI by DNA content analysis and single cell RNA-sequencing. Furthermore, we study the functional roles of polyploidization using transgenic models and drug interventions. We identify YAP1-driven TC polyploidization outside the site of injury as a rapid way to sustain residual kidney function early during AKI. This survival mechanism comes at the cost of senescence of polyploid TC promoting interstitial fibrosis and CKD in AKI survivors. However, targeting TC polyploidization after the early AKI phase can prevent AKI-CKD transition without influencing AKI lethality. Senolytic treatment prevents CKD by blocking repeated TC polyploidization cycles. These results revise the current pathophysiological concept of how the kidney responds to acute injury and identify a novel druggable target to improve prognosis in AKI survivors.


Acute Kidney Injury , Renal Insufficiency, Chronic , Acute Kidney Injury/metabolism , DNA/metabolism , Disease Progression , Humans , Kidney/metabolism , Polyploidy , RNA/metabolism , Renal Insufficiency, Chronic/genetics , Renal Insufficiency, Chronic/metabolism , Senotherapeutics
6.
Sci Transl Med ; 14(657): eabg3277, 2022 08 10.
Article En | MEDLINE | ID: mdl-35947676

Crescentic glomerulonephritis is characterized by vascular necrosis and parietal epithelial cell hyperplasia in the space surrounding the glomerulus, resulting in the formation of crescents. Little is known about the molecular mechanisms driving this process. Inducing crescentic glomerulonephritis in two Pax2Cre reporter mouse models revealed that crescents derive from clonal expansion of single immature parietal epithelial cells. Preemptive and delayed histone deacetylase inhibition with panobinostat, a drug used to treat hematopoietic stem cell disorders, attenuated crescentic glomerulonephritis with recovery of kidney function in the two mouse models. Three-dimensional confocal microscopy and stimulated emission depletion superresolution imaging of mouse glomeruli showed that, in addition to exerting an anti-inflammatory and immunosuppressive effect, panobinostat induced differentiation of an immature hyperplastic parietal epithelial cell subset into podocytes, thereby restoring the glomerular filtration barrier. Single-cell RNA sequencing of human renal progenitor cells in vitro identified an immature stratifin-positive cell subset and revealed that expansion of this stratifin-expressing progenitor cell subset was associated with a poor outcome in human crescentic glomerulonephritis. Treatment of human parietal epithelial cells in vitro with panobinostat attenuated stratifin expression in renal progenitor cells, reduced their proliferation, and promoted their differentiation into podocytes. These results offer mechanistic insights into the formation of glomerular crescents and demonstrate that selective targeting of renal progenitor cells can attenuate crescent formation and the deterioration of kidney function in crescentic glomerulonephritis in mice.


Glomerulonephritis , Podocytes , Animals , Disease Models, Animal , Glomerulonephritis/drug therapy , Humans , Kidney/metabolism , Mice , Panobinostat/therapeutic use , Podocytes/metabolism , Stem Cells/metabolism
7.
Front Cell Dev Biol ; 10: 838272, 2022.
Article En | MEDLINE | ID: mdl-35281116

Podocytopathies are a group of proteinuric glomerular disorders driven by primary podocyte injury that are associated with a set of lesion patterns observed on kidney biopsy, i.e., minimal changes, focal segmental glomerulosclerosis, diffuse mesangial sclerosis and collapsing glomerulopathy. These unspecific lesion patterns have long been considered as independent disease entities. By contrast, recent evidence from genetics and experimental studies demonstrated that they represent signs of repeated injury and repair attempts. These ongoing processes depend on the type, length, and severity of podocyte injury, as well as on the ability of parietal epithelial cells to drive repair. In this review, we discuss the main pathology patterns of podocytopathies with a focus on the cellular and molecular response of podocytes and parietal epithelial cells.

9.
J Pers Med ; 11(11)2021 Oct 27.
Article En | MEDLINE | ID: mdl-34834449

Adrenocortical carcinoma (ACC) is a rare malignancy with poor prognosis when metastatic and scarce treatment options in the advanced stages. In solid tumors, the chemokine CXCL12/CXCR4 axis is involved in the metastatic process. We demonstrated that the human adrenocortex expressed CXCL12 and its cognate receptors CXCR4 and CXCR7, not only in physiological conditions, but also in ACC, where the receptors' expression was higher and the CXCL12 expression was lower than in the physiological conditions. In a small pilot cohort of 22 ACC patients, CXCL12 negatively correlated with tumor size, stage, Weiss score, necrosis, and mitotic activity. In a Kaplan-Meier analysis, the CXCL12 tumor expression significantly predicted disease-free, progression-free, and overall survival. In vitro treatment of the primary ACC H295R and of the metastatic MUC-1 cell line with the PPARγ-ligand rosiglitazone (RGZ) dose-dependently reduced proliferation, resulting in a significant increase in CXCL12 and a decrease in its receptors in the H295R cells only, with no effect on the MUC-1 levels. In ACC mouse xenografts, tumor growth was inhibited by the RGZ treatment before tumor development (prevention-setting) and once the tumor had grown (therapeutic-setting), similarly to mitotane (MTT). This inhibition was associated with a significant suppression of the tumor CXCR4/CXCR7 and the stimulation of human CXCL12 expression. Tumor growth correlated inversely with CXCL12 and positively with CXCR4 expression, suggesting that local CXCL12 may impair the primary tumor cell response to the ligand gradient that may contribute to driving the tumor progression. These findings indicate that CXCL12/CXCR4 may constitute a potential target for anti-cancer agents such as rosiglitazone in the treatment of ACC.

10.
Cancers (Basel) ; 13(18)2021 Sep 13.
Article En | MEDLINE | ID: mdl-34572815

Sex and gender disparities have been reported for different types of non-reproductive cancers. Males are two times more likely to develop kidney cancer than females and have a higher death rate. These differences can be explained by looking at genetics and genomics, as well as other risk factors such as hypertension and obesity, lifestyle, and female sex hormones. Examination of the hormonal signaling pathways bring further insights into sex-related differences. Sex and gender-based disparities can be observed at the diagnostic, histological and treatment levels, leading to significant outcome difference. This review summarizes the current knowledge about sex and gender-related differences in the clinical presentation of patients with kidney cancer and the possible biological mechanisms that could explain these observations. Underlying sex-based differences may contribute to the development of sex-specific prognostic and diagnostic tools and the improvement of personalized therapies.

11.
Am J Kidney Dis ; 78(5): 750-754, 2021 11.
Article En | MEDLINE | ID: mdl-33872687

Aicardi-Goutières syndrome (AGS) is a well-characterized monogenic type I interferonopathy presenting with prominent neurologic manifestations. Among extraneurologic features, renal involvement has been described in only 1 patient with an IFIH1 mutation in whom membranous nephropathy developed. The pathogenic role of augmented interferon (IFN) signaling in tissues other than the central nervous system remains to be elucidated. We report a case of collapsing glomerulopathy in a 15-year-old girl affected by AGS with RNASEH2B mutation (an alanine-to-threonine change at amino acid 177), which led to kidney failure. The patient had no lupus-like features and lacked the APOL1 G1 and G2 risk alleles. Kidney biopsy showed findings consistent with collapsing glomerulopathy. MxA, a protein involved in antiviral immunity and induced by type I IFNs, was selectively expressed in CD133-positive parietal epithelial cells (PECs) but not in podocytes that stained for synaptopodin or in other glomerular cells. MxA also colocalized within pseudocrescents with CD44, a marker of PEC activation involved in cellular proliferation, differentiation, and migration and in glomerular scarring. Our findings suggest that collapsing glomerulopathy can be a complication of the type I interferonopathy AGS and that a constitutively enhanced type I IFN response in CD133-positive PECs can drive collapsing glomerulopathy.


Autoimmune Diseases of the Nervous System , Interferon Type I , Nervous System Malformations , Adolescent , Apolipoprotein L1 , Autoimmune Diseases of the Nervous System/genetics , Female , Humans , Kidney Glomerulus , Nervous System Malformations/genetics
12.
Nephrol Dial Transplant ; 36(1): 19-28, 2021 01 01.
Article En | MEDLINE | ID: mdl-31325314

The important achievements in kidney physiological and pathophysiological mechanisms can largely be ascribed to progress in the technology of microscopy. Much of what we know about the architecture of the kidney is based on the fundamental descriptions of anatomic microscopists using light microscopy and later by ultrastructural analysis provided by electron microscopy. These two techniques were used for the first classification systems of kidney diseases and for their constant updates. More recently, a series of novel imaging techniques added the analysis in further dimensions of time and space. Confocal microscopy allowed us to sequentially visualize optical sections along the z-axis and the availability of specific analysis software provided a three-dimensional rendering of thicker tissue specimens. Multiphoton microscopy permitted us to simultaneously investigate kidney function and structure in real time. Fluorescence-lifetime imaging microscopy allowed to study the spatial distribution of metabolites. Super-resolution microscopy increased sensitivity and resolution up to nanoscale levels. With cryo-electron microscopy, researchers could visualize the individual biomolecules at atomic levels directly in the tissues and understand their interaction at subcellular levels. Finally, matrix-assisted laser desorption/ionization imaging mass spectrometry permitted the measuring of hundreds of different molecules at the same time on tissue sections at high resolution. This review provides an overview of available kidney imaging strategies, with a focus on the possible impact of the most recent technical improvements.


Cryoelectron Microscopy/methods , Image Processing, Computer-Assisted/methods , Kidney Diseases/diagnostic imaging , Kidney/diagnostic imaging , Microscopy, Fluorescence/methods , Molecular Imaging/methods , Animals , Humans , Kidney/cytology , Kidney/metabolism , Kidney Diseases/metabolism , Kidney Diseases/pathology , Software
13.
Sci Rep ; 10(1): 16683, 2020 10 07.
Article En | MEDLINE | ID: mdl-33028882

Retinoic acid (RA) activates RA receptors (RAR), resulting in RA response element (RARE)-dependent gene expression in renal collecting duct (CD). Emerging evidence supports a protective role for this activity in acute kidney injury (AKI) and chronic kidney disease (CKD). Herein, we examined this activity in RARE-LacZ transgenic mice and by RARE-Luciferase reporter assays in CD cells, and investigated how this activity responds to neurotransmitters and mediators of kidney injury. In RARE-LacZ mice, Adriamycin-induced heavy albuminuria was associated with reduced RA/RAR activity in CD cells. In cultured CD cells, RA/RAR activity was repressed by acetylcholine, albumin, aldosterone, angiotensin II, high glucose, cisplatin and lipopolysaccharide, but was induced by aristolochic acid I, calcitonin gene-related peptide, endothelin-1, gentamicin, norepinephrine and vasopressin. Compared with age-matched normal human CD cells, CD-derived renal cystic epithelial cells from patients with autosomal recessive polycystic kidney disease (ARPKD) had significantly lower RA/RAR activity. Synthetic RAR agonist RA-568 was more potent than RA in rescuing RA/RAR activity repressed by albumin, high glucose, angiotensin II, aldosterone, cisplatin and lipopolysaccharide. Hence, RA/RAR  in CD cells is a convergence point of regulation by neurotransmitters and mediators of kidney injury, and may be a novel therapeutic target.


Kidney Diseases/metabolism , Kidney Tubules, Collecting/metabolism , Receptors, Retinoic Acid/metabolism , Tretinoin/metabolism , Acetylcholine/pharmacology , Albumins/pharmacology , Aldosterone/pharmacology , Angiotensin II/pharmacology , Animals , Calcitonin Gene-Related Peptide/pharmacology , Cell Line , Cisplatin/pharmacology , Endothelin-1/pharmacology , Female , Glucose/pharmacology , Humans , Kidney Tubules, Collecting/cytology , Kidney Tubules, Collecting/drug effects , Lipopolysaccharides/pharmacology , Mice , Mice, Transgenic , Vasopressins/pharmacology
14.
J Am Soc Nephrol ; 31(12): 2773-2792, 2020 12.
Article En | MEDLINE | ID: mdl-32938648

BACKGROUND: The roles of asymptomatic hyperuricemia or uric acid (UA) crystals in CKD progression are unknown. Hypotheses to explain links between UA deposition and progression of CKD include that (1) asymptomatic hyperuricemia does not promote CKD progression unless UA crystallizes in the kidney; (2) UA crystal granulomas may form due to pre-existing CKD; and (3) proinflammatory granuloma-related M1-like macrophages may drive UA crystal-induced CKD progression. METHODS: MALDI-FTICR mass spectrometry, immunohistochemistry, 3D confocal microscopy, and flow cytometry were used to characterize a novel mouse model of hyperuricemia and chronic UA crystal nephropathy with granulomatous nephritis. Interventional studies probed the role of crystal-induced inflammation and macrophages in the pathology of progressive CKD. RESULTS: Asymptomatic hyperuricemia alone did not cause CKD or drive the progression of aristolochic acid I-induced CKD. Only hyperuricemia with UA crystalluria due to urinary acidification caused tubular obstruction, inflammation, and interstitial fibrosis. UA crystal granulomas surrounded by proinflammatory M1-like macrophages developed late in this process of chronic UA crystal nephropathy and contributed to the progression of pre-existing CKD. Suppressing M1-like macrophages with adenosine attenuated granulomatous nephritis and the progressive decline in GFR. In contrast, inhibiting the JAK/STAT inflammatory pathway with tofacitinib was not renoprotective. CONCLUSIONS: Asymptomatic hyperuricemia does not affect CKD progression unless UA crystallizes in the kidney. UA crystal granulomas develop late in chronic UA crystal nephropathy and contribute to CKD progression because UA crystals trigger M1-like macrophage-related interstitial inflammation and fibrosis. Targeting proinflammatory macrophages, but not JAK/STAT signaling, can attenuate granulomatous interstitial nephritis.


Hyperuricemia/complications , Hyperuricemia/pathology , Nephritis, Interstitial/etiology , Nephritis, Interstitial/pathology , Renal Insufficiency, Chronic/etiology , Renal Insufficiency, Chronic/pathology , Animals , Asymptomatic Diseases , Disease Models, Animal , Disease Progression , Granuloma/etiology , Granuloma/metabolism , Granuloma/pathology , Hyperuricemia/metabolism , Mice , Nephritis, Interstitial/blood , Renal Insufficiency, Chronic/blood
15.
J Am Soc Nephrol ; 31(8): 1729-1745, 2020 08.
Article En | MEDLINE | ID: mdl-32576600

BACKGROUND: Progression of CKD in type 2 diabetes, despite dual inhibition of sodium-glucose transporter-2 and the renin-angiotensin system, remains a concern. Bromoindirubin-3'-oxime (BIO), previously reported to promote podocyte survival and regeneration, is a candidate additional drug to elicit renoprotective effects beyond therapy with metformin, ramipril, and empagliflozin (MRE). Evaluating a drug with standard therapeutics more closely mimics the clinical setting than evaluating the drug alone. METHODS: Uninephrectomized BKS-Lepr-/- (db/db) mice treated with or without MRE served as a model of progressive CKD in type 2 diabetes. Mice on or off MRE were randomized to only 4 weeks of add-on BIO or vehicle. The primary end point was slope of GFR (ΔGFR). RESULTS: Four weeks of MRE treatment alone did not affect ΔGFR, but significantly attenuated hyperglycemia, albuminuria, and glomerulosclerosis and increased podocyte filtration slit density, as assessed by STED super-resolution microscopy upon tissue clearing. BIO alone improved albuminuria, podocyte density in superficial and juxtamedullary nephrons, and podocyte filtration slit density. MRE+BIO combination therapy had additive protective effects on ΔGFR, glomerulosclerosis, podocyte density in juxtamedullary nephrons, and filtration slit density. CONCLUSIONS: Add-on treatment with BIO for only 4 weeks attenuates progression of CKD beyond MRE therapy in mice with type 2 diabetes. Additional drug combinations may help to further delay ESKD in type 2 diabetes.


Benzhydryl Compounds/administration & dosage , Diabetes Mellitus, Type 2/drug therapy , Diabetic Nephropathies/prevention & control , Glucosides/administration & dosage , Indoles/therapeutic use , Metformin/administration & dosage , Oximes/therapeutic use , Ramipril/administration & dosage , Animals , Diabetes Mellitus, Type 2/physiopathology , Diabetic Nephropathies/physiopathology , Disease Progression , Drug Therapy, Combination , Glomerular Filtration Rate/drug effects , Glycogen Synthase Kinase 3 beta/antagonists & inhibitors , Kidney/drug effects , Mice , Podocytes/drug effects
16.
Sci Transl Med ; 12(536)2020 03 25.
Article En | MEDLINE | ID: mdl-32213630

Acute tissue injury causes DNA damage and repair processes involving increased cell mitosis and polyploidization, leading to cell function alterations that may potentially drive cancer development. Here, we show that acute kidney injury (AKI) increased the risk for papillary renal cell carcinoma (pRCC) development and tumor relapse in humans as confirmed by data collected from several single-center and multicentric studies. Lineage tracing of tubular epithelial cells (TECs) after AKI induction and long-term follow-up in mice showed time-dependent onset of clonal papillary tumors in an adenoma-carcinoma sequence. Among AKI-related pathways, NOTCH1 overexpression in human pRCC associated with worse outcome and was specific for type 2 pRCC. Mice overexpressing NOTCH1 in TECs developed papillary adenomas and type 2 pRCCs, and AKI accelerated this process. Lineage tracing in mice identified single renal progenitors as the cell of origin of papillary tumors. Single-cell RNA sequencing showed that human renal progenitor transcriptome showed similarities to PT1, the putative cell of origin of human pRCC. Furthermore, NOTCH1 overexpression in cultured human renal progenitor cells induced tumor-like 3D growth. Thus, AKI can drive tumorigenesis from local tissue progenitor cells. In particular, we find that AKI promotes the development of pRCC from single progenitors through a classical adenoma-carcinoma sequence.


Acute Kidney Injury , Adenoma , Carcinoma, Renal Cell , Kidney Neoplasms , Adenoma/genetics , Animals , Biomarkers, Tumor , Carcinoma, Renal Cell/genetics , Kidney Neoplasms/genetics , Mice , Neoplasm Recurrence, Local , Stem Cells
17.
Trends Mol Med ; 25(5): 366-381, 2019 05.
Article En | MEDLINE | ID: mdl-30935780

In acute organ failure, rapid compensation of function loss assures survival. Dedifferentiation and/or proliferation of surviving parenchymal cells could imply a transient (and potentially fatal) impairment of residual functional performance. However, evolution has selected two flexible life-saving mechanisms acting synergistically on organ function recovery. Sustaining residual performance is possible when the remnant differentiated parenchymal cells avoid cell division, but increase function by undergoing hypertrophy via endoreplication, leading to polyploid cells. In addition, tissue progenitors, representing a subset of less-differentiated and/or self-renewing parenchymal cells completing cytokinesis, proliferate and differentiate to regenerate lost parenchymal cells. Here, we review the evolving evidence on polyploidization and progenitor-driven regeneration in acute liver, heart, and kidney failure with evolutionary advantages and trade-offs in organ repair.


Acute Kidney Injury/metabolism , Acute Kidney Injury/mortality , Heart Failure/metabolism , Heart Failure/mortality , Liver Failure, Acute/metabolism , Liver Failure, Acute/mortality , Acute Disease , Acute Kidney Injury/etiology , Animals , Cell Division , Cell Proliferation , Cell Survival , Heart Failure/etiology , Heart Failure/physiopathology , Humans , Liver Failure, Acute/etiology , Organ Specificity , Polyploidy
18.
Kidney Int ; 94(6): 1111-1126, 2018 12.
Article En | MEDLINE | ID: mdl-30385042

Insufficient podocyte regeneration after injury is a central pathomechanism of glomerulosclerosis and chronic kidney disease. Podocytes constitutively secrete the chemokine CXCL12, which is known to regulate homing and activation of stem cells; hence we hypothesized a similar effect of CXCL12 on podocyte progenitors. CXCL12 blockade increased podocyte numbers and attenuated proteinuria in mice with Adriamycin-induced nephropathy. Similar studies in lineage-tracing mice revealed enhanced de novo podocyte formation from parietal epithelial cells in the setting of CXCL12 blockade. Super-resolution microscopy documented full integration of these progenitor-derived podocytes into the glomerular filtration barrier, interdigitating with tertiary foot processes of neighboring podocytes. Quantitative 3D analysis revealed that conventional 2D analysis underestimated the numbers of progenitor-derived podocytes. The 3D analysis also demonstrated differences between juxtamedullary and cortical nephrons in both progenitor endowment and Adriamycin-induced podocyte loss, with more robust podocyte regeneration in cortical nephrons with CXCL12 blockade. Finally, we found that delayed CXCL12 inhibition still had protective effects. In vitro studies found that CXCL12 inhibition uncoupled Notch signaling in podocyte progenitors. These data suggest that CXCL12-driven podocyte-progenitor feedback maintains progenitor quiescence during homeostasis, but also limits their intrinsic capacity to regenerate lost podocytes, especially in cortical nephrons. CXCL12 inhibition could be an innovative therapeutic strategy in glomerular disorders.


Aptamers, Nucleotide/pharmacology , Chemokine CXCL12/antagonists & inhibitors , Glomerulosclerosis, Focal Segmental/drug therapy , Regeneration/drug effects , Stem Cells/drug effects , Animals , Aptamers, Nucleotide/therapeutic use , Cell Differentiation/drug effects , Cells, Cultured , Chemokine CXCL12/metabolism , Disease Models, Animal , Doxorubicin/toxicity , Feedback, Physiological/drug effects , Glomerulosclerosis, Focal Segmental/chemically induced , Glomerulosclerosis, Focal Segmental/complications , Humans , Imaging, Three-Dimensional , Male , Mice , Mice, Transgenic , Microscopy, Confocal/methods , Podocytes/drug effects , Podocytes/pathology , Proteinuria/drug therapy , Proteinuria/etiology , Stem Cells/physiology , Treatment Outcome
19.
Expert Opin Biol Ther ; 18(7): 795-806, 2018 07.
Article En | MEDLINE | ID: mdl-29939787

INTRODUCTION: Chronic kidney disease is a major health-care problem worldwide and its cost is becoming no longer affordable. Indeed, restoring damaged renal structures or building a new kidney represents an ambitious and ideal alternative to renal replacement therapy. Streams of research have explored the possible application of pluripotent stem cells (SCs) (embryonic SCs and induced pluripotent SCs) in different strategies aimed at regenerate functioning nephrons and at understanding the mechanisms of kidney regeneration. AREAS COVERED: In this review, we will focus on the main potential applications of human pluripotent SCs to kidney regeneration, including those leading to rebuilding new kidneys or part of them (organoids, scaffolds, biological microdevices) as well as those aimed at understanding the pathophysiological mechanisms of renal disease and regenerative processes (modeling of kidney disease, genome editing). Moreover, we will discuss the role of endogenous renal progenitors cells in order to understand and promote kidney regeneration, as an attractive alternative to pluripotent SCs. EXPERT OPINION: Opportunities and pitfalls of all these strategies will be underlined, finally leading to the conclusion that a deeper knowledge of the biology of pluripotent SCs is mandatory, in order to allow us to hypothesize their clinical application.


Kidney/physiology , Pluripotent Stem Cells/transplantation , Regeneration/physiology , Renal Insufficiency, Chronic/therapy , Stem Cells/physiology , Animals , Cell Differentiation , Embryonic Stem Cells , Humans , Induced Pluripotent Stem Cells/physiology , Induced Pluripotent Stem Cells/transplantation , Pluripotent Stem Cells/physiology , Stem Cell Transplantation/methods
20.
Nat Commun ; 9(1): 1344, 2018 04 09.
Article En | MEDLINE | ID: mdl-29632300

Acute kidney injury (AKI) is considered largely reversible based on the capacity of surviving tubular cells to dedifferentiate and replace lost cells via cell division. Here we show by tracking individual tubular cells in conditional Pax8/Confetti mice that kidney function is  recovered after AKI despite substantial tubular cell loss. Cell cycle and ploidy analysis upon AKI in conditional Pax8/FUCCI2aR mice and human biopsies identify endocycle-mediated hypertrophy of tubular cells. By contrast, a small subset of Pax2+ tubular progenitors enriches via higher stress resistance and clonal expansion and regenerates necrotic tubule segments, a process that can be enhanced by suitable drugs. Thus,  renal functional recovery upon AKI involves remnant tubular cell hypertrophy via endocycle and limited progenitor-driven regeneration that can be pharmacologically enhanced.


Acute Kidney Injury/pathology , Acute Kidney Injury/physiopathology , Acute Kidney Injury/genetics , Adult Stem Cells/pathology , Animals , Cell Cycle , Cell Dedifferentiation , Cell Enlargement , Cell Lineage , Epithelial Cells/drug effects , Epithelial Cells/pathology , Female , Histone Deacetylase Inhibitors/pharmacology , Humans , Kidney Tubules/drug effects , Kidney Tubules/pathology , Kidney Tubules/physiopathology , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , PAX2 Transcription Factor/metabolism , PAX8 Transcription Factor/metabolism , Ploidies , Regeneration/drug effects , Single-Cell Analysis
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