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Molecular Therapy : the Journal of the... Sep 2022Clopidogrel, a P2Y12 inhibitor, is a novel anti-fibrosis agent for chronic kidney disease (CKD), but its mechanisms remain unclear, which we investigated by silencing...
Clopidogrel, a P2Y12 inhibitor, is a novel anti-fibrosis agent for chronic kidney disease (CKD), but its mechanisms remain unclear, which we investigated by silencing P2Y12 or treating unilateral ureteral obstruction (UUO) in LysM-Cre/Rosa Tomato mice with clopidogrel in vivo and in vitro. We found that P2Y12 was significantly increased and correlated with progressive renal fibrosis in CKD patients and UUO mice. Phenotypically, up to 82% of P2Y12-expressing cells within the fibrosing kidney were of macrophage origin, identified by co-expressing CD68/F4/80 antigens or a macrophage-lineage-tracing marker Tomato. Unexpectedly, more than 90% of P2Y12-expressing macrophages were undergoing macrophage-to-myofibroblast transition (MMT) by co-expressing alpha smooth muscle actin (α-SMA), which was also confirmed by single-cell RNA sequencing. Functionally, clopidogrel improved the decline rate of the estimated glomerular filtration rate (eGFR) in patients with CKD and significantly inhibited renal fibrosis in UUO mice. Mechanistically, P2Y12 expression was induced by transforming growth factor β1 (TGF-β1) and promoted MMT via the Smad3-dependent mechanism. Thus, silencing or pharmacological inhibition of P2Y12 was capable of inhibiting TGF-β/Smad3-mediated MMT and progressive renal fibrosis in vivo and in vitro. In conclusion, P2Y12 is highly expressed by macrophages in fibrosing kidneys and mediates renal fibrosis by promoting MMT via TGF-β/Smad3 signaling. Thus, P2Y12 inhibitor maybe a novel and effective anti-fibrosis agent for CKD.
Topics: Animals; Clopidogrel; Fibrosis; Kidney; Kidney Diseases; Macrophages; Mice; Mice, Inbred C57BL; Myofibroblasts; Renal Insufficiency, Chronic; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta; Transforming Growth Factor beta1; Ureteral Obstruction
PubMed: 35791881
DOI: 10.1016/j.ymthe.2022.06.019 -
International Journal of Molecular... Jun 2021Acute kidney injury (AKI) is a global health challenge of vast proportions, as approx. 13.3% of people worldwide are affected annually. The pathophysiology of AKI is... (Review)
Review
Acute kidney injury (AKI) is a global health challenge of vast proportions, as approx. 13.3% of people worldwide are affected annually. The pathophysiology of AKI is very complex, but its main causes are sepsis, ischemia, and nephrotoxicity. Nephrotoxicity is mainly associated with the use of drugs. Drug-induced AKI accounts for 19-26% of all hospitalized cases. Drug-induced nephrotoxicity develops according to one of the three mechanisms: (1) proximal tubular injury and acute tubular necrosis (ATN) (a dose-dependent mechanism), where the cause is related to apical contact with drugs or their metabolites, the transport of drugs and their metabolites from the apical surface, and the secretion of drugs from the basolateral surface into the tubular lumen; (2) tubular obstruction by crystals or casts containing drugs and their metabolites (a dose-dependent mechanism); (3) interstitial nephritis induced by drugs and their metabolites (a dose-independent mechanism). In this article, the mechanisms of the individual types of injury will be described. Specific groups of drugs will be linked to specific injuries. Additionally, the risk factors for the development of AKI and the methods for preventing and/or treating the condition will be discussed.
Topics: Animals; Drug-Related Side Effects and Adverse Reactions; Humans; Immune Checkpoint Inhibitors; Kidney; Kidney Diseases; Kidney Tubules; Metabolome
PubMed: 34204029
DOI: 10.3390/ijms22116109 -
International Journal of Biological... 2020Ruxolitinib is a selective inhibitor of Jak1/2. Downstream signaling pathways of Jak, such as Stat3 and Akt/mTOR, are overactivated and contribute to renal interstitial...
Ruxolitinib is a selective inhibitor of Jak1/2. Downstream signaling pathways of Jak, such as Stat3 and Akt/mTOR, are overactivated and contribute to renal interstitial fibrosis. Therefore, we explored the effect of Ruxolitinib on this pathological process. Unilateral ureteral obstruction (UUO) models and TGF-β1-treated fibroblasts and renal tubular epithelial cells were adopted in this study. Ruxolitinib was administered to UUO mice and TGF-β1-treated cells. Kidneys from UUO mice with Ruxolitinib treatment displayed less tubular injuries compared with those without Ruxolitinib treatment. Ruxolitinib treatment suppressed fibroblast activation and extracellular matrix (ECM) production in UUO kidneys and TGF-β1-treated fibroblasts. Ruxolitinib treatment also blocked epithelial-mesenchymal transition (EMT) in UUO kidneys and TGF-β 1-treated renal tubular epithelial cells. Moreover, Ruxolitinib treatment alleviated UUO-induced inflammation, oxidative stress and apoptosis. Mechanistically, Ruxolitinib treatment attenuated activation of both Stat3 and Akt/mTOR/Yap pathways. In conclusion, Ruxolitinib treatment can ameliorate UUO-induced renal interstitial fibrosis, suggesting that Ruxolitinib may be potentially used to treat fibrotic kidney disease.
Topics: Animals; Apoptosis; Blotting, Western; Cell Line; Chemokine CCL2; Epithelial Cells; Epithelial-Mesenchymal Transition; Fibroblasts; Fibrosis; Immunohistochemistry; In Situ Nick-End Labeling; Janus Kinase 1; Janus Kinase 2; Kidney Diseases; Male; Mice; Mice, Inbred C57BL; Nitriles; Oxidative Stress; Pyrazoles; Pyrimidines; RNA, Messenger; Rats; Real-Time Polymerase Chain Reaction; STAT3 Transcription Factor; Signal Transduction; Transforming Growth Factor beta1; Ureteral Obstruction
PubMed: 31929748
DOI: 10.7150/ijbs.39024 -
Nature Communications Jan 2022Loss of Klotho, an anti-aging protein, plays a critical role in the pathogenesis of chronic kidney diseases. As Klotho is a large transmembrane protein, it is...
Loss of Klotho, an anti-aging protein, plays a critical role in the pathogenesis of chronic kidney diseases. As Klotho is a large transmembrane protein, it is challenging to harness it as a therapeutic remedy. Here we report the discovery of a Klotho-derived peptide 1 (KP1) protecting kidneys by targeting TGF-β signaling. By screening a series of peptides derived from human Klotho protein, we identified KP1 that repressed fibroblast activation by binding to TGF-β receptor 2 (TβR2) and disrupting the TGF-β/TβR2 engagement. As such, KP1 blocked TGF-β-induced activation of Smad2/3 and mitogen-activated protein kinases. In mouse models of renal fibrosis, intravenous injection of KP1 resulted in its preferential accumulation in injured kidneys. KP1 preserved kidney function, repressed TGF-β signaling, ameliorated renal fibrosis and restored endogenous Klotho expression. Together, our findings suggest that KP1 recapitulates the anti-fibrotic action of Klotho and offers a potential remedy in the fight against fibrotic kidney diseases.
Topics: Amino Acid Sequence; Animals; Cell Line; Disease Models, Animal; Fibrosis; Humans; Inflammation; Kidney; Kidney Diseases; Klotho Proteins; Male; Mice, Inbred BALB C; Peptides; Phosphorylation; Protective Agents; Protein Binding; Rats; Receptors, Transforming Growth Factor beta; Reperfusion Injury; Signal Transduction; Smad Proteins; Transforming Growth Factor beta; Ureteral Obstruction; Mice
PubMed: 35064106
DOI: 10.1038/s41467-022-28096-z -
Theranostics 2021Ureteral obstruction-induced hydronephrosis is associated with renal fibrosis and progressive chronic kidney disease (CKD). Exosome-mediated cell-cell communication has...
Ureteral obstruction-induced hydronephrosis is associated with renal fibrosis and progressive chronic kidney disease (CKD). Exosome-mediated cell-cell communication has been suggested to be involved in various diseases, including renal fibrosis. However, little is known regarding how exosomes regulate renal fibrosis in obstructed kidneys. We first examined the secretion of exosomes in UUO (unilateral ureteral obstruction) mouse kidneys and TGF-β1-stimulated tubular epithelial cells (NRK-52E). Exosomes from NRK-52E cells were subsequently harvested and incubated with fibroblasts (NRK-49F) or injected into UUO mice via the tail vein. We next constructed Rab27a knockout mice to further confirm the role of exosome-mediated epithelial-fibroblast communication relevant to renal fibrosis in UUO mice. High-throughput miRNA sequencing was performed to detect the miRNA profiles of TGFβ1-Exos. The roles of candidate miRNAs, their target genes and relevant pathways were predicted and assessed and by setting specific miRNA mimic, miRNA inhibitor, siRNA or miRNA LNA groups. Increased renal fibrosis was associated with prolonged UUO days, and the secretion of exosomes was markedly increased in UUO kidneys and TGF-β1-stimulated NRK-52E cells. Purified exosomes from TGF-β1-stimulated NRK-52E cells could activate fibroblasts and aggravate renal fibrosis and . In addition, the inhibition of exosome secretion by Rab27a knockout or GW4869 treatment abolished fibroblast activation and ameliorated renal fibrosis. Exosomal miR-21 was significantly increased in TGFβ1-Exos compared with Ctrl-Exos, and PTEN is a certain target of miR-21. The promotion or inhibition of epithelial exosomal miR-21 correspondingly accelerated or abolished fibroblast activation , and renal fibrosis after UUO was alleviated by miR-21-deficient exosomes through the PTEN/Akt pathway. Our findings reveal that exosomal miR-21 from tubular epithelial cells may accelerate the development of renal fibrosis by activating fibroblasts via the miR-21/PTEN/Akt pathway in obstructed kidneys.
Topics: Animals; Cell Line; China; Epithelial Cells; Exosomes; Fibroblasts; Fibrosis; Kidney; Kidney Diseases; Kidney Tubules; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; MicroRNAs; PTEN Phosphohydrolase; Signal Transduction; Transforming Growth Factor beta1; Ureteral Obstruction
PubMed: 34522205
DOI: 10.7150/thno.62820 -
The Journal of Clinical Investigation Jun 2022The roles of neutrophils in renal inflammation are currently unclear. On examining these cells in the unilateral ureteral obstruction murine model of chronic kidney...
The roles of neutrophils in renal inflammation are currently unclear. On examining these cells in the unilateral ureteral obstruction murine model of chronic kidney disease, we found that the injured kidney bore a large and rapidly expanding population of neutrophils that expressed the eosinophil marker Siglec-F. We first verified that these cells were neutrophils. Siglec-F+ neutrophils were recently detected in several studies in other disease contexts. We then showed that a) these cells were derived from conventional neutrophils in the renal vasculature by TGF-β1 and GM-CSF; b) they differed from their parent cells by more frequent hypersegmentation, higher expression of profibrotic inflammatory cytokines, and notably, expression of collagen 1; and c) their depletion reduced collagen deposition and disease progression, but adoptive transfer increased renal fibrosis. These findings have thus unveiled a subtype of neutrophils that participate in renal fibrosis and a potentially new therapeutic target in chronic kidney disease.
Topics: Animals; Collagen; Fibrosis; Kidney; Kidney Diseases; Mice; Neutrophils; Renal Insufficiency, Chronic; Sialic Acid Binding Immunoglobulin-like Lectins; Transforming Growth Factor beta1; Ureteral Obstruction
PubMed: 35482420
DOI: 10.1172/JCI156876 -
Seminars in Liver Disease Feb 2020Acute kidney injury (AKI) is a dreaded complication in patients with liver disease and jaundice, since it is associated with significant morbidity and mortality.... (Review)
Review
Acute kidney injury (AKI) is a dreaded complication in patients with liver disease and jaundice, since it is associated with significant morbidity and mortality. Cholemic nephropathy (CN) is thought to represent a widely underestimated important cause of AKI in advanced liver diseases with jaundice. The umbrella term CN describes impaired renal function along with histomorphological changes consisting of intratubular cast formation and tubular epithelial cell injury directed primarily toward distal nephron segments. In cholestasis, biliary constituents may be excreted via the kidney and bilirubin or bile acids may trigger tubular injury and cast formation, but as we begin to understand the underlying pathophysiologic mechanisms, we become increasingly aware of the urgent need for clearly defined diagnostic criteria. In the following, we aim to summarize current knowledge of clinical and morphological characteristics of CN, discuss potential pathomechanisms, and raise key questions to stimulate evolution of a research strategy for CN.
Topics: Acute Kidney Injury; Animals; Bile Acids and Salts; Bilirubin; Cholestasis; Disease Models, Animal; Humans; Jaundice, Obstructive; Liver Diseases
PubMed: 31627236
DOI: 10.1055/s-0039-1698826 -
Clinical Science (London, England :... Aug 2021Although accelerated cellular senescence is closely related to the progression of chronic kidney disease (CKD) and renal fibrosis, the underlying mechanisms remain...
Although accelerated cellular senescence is closely related to the progression of chronic kidney disease (CKD) and renal fibrosis, the underlying mechanisms remain largely unknown. Here, we reported that tubular aberrant expression of Brahma-related gene 1 (BRG1), an enzymatic subunit of the SWItch/Sucrose Non-Fermentable complex, is critically involved in tubular senescence and renal fibrosis. BRG1 was significantly up-regulated in the kidneys, predominantly in tubular epithelial cells, of both CKD patients and unilateral ureteral obstruction (UUO) mice. In vivo, shRNA-mediated knockdown of BRG1 significantly ameliorated renal fibrosis, improved tubular senescence, and inhibited UUO-induced activation of Wnt/β-catenin pathway. In mouse renal tubular epithelial cells (mTECs) and primary renal tubular cells, inhibition of BRG1 diminished transforming growth factor-β1 (TGF-β1)-induced cellular senescence and fibrotic responses. Correspondingly, ectopic expression of BRG1 in mTECs or normal kidneys increased p16INK4a, p19ARF, and p21 expression and senescence-associated β-galactosidase (SA-β-gal) activity, indicating accelerated tubular senescence. Additionally, BRG1-mediated pro-fibrotic responses were largely abolished by small interfering RNA (siRNA)-mediated p16INK4a silencing in vitro or continuous senolytic treatment with ABT-263 in vivo. Moreover, BRG1 activated the Wnt/β-catenin pathway, which further inhibited autophagy. Pharmacologic inhibition of the Wnt/β-catenin pathway (ICG-001) or rapamycin (RAPA)-mediated activation of autophagy effectively blocked BRG1-induced tubular senescence and fibrotic responses, while bafilomycin A1 (Baf A1)-mediated inhibition of autophagy abolished the effects of ICG-001. Further, BRG1 altered the secretome of senescent tubular cells, which promoted proliferation and activation of fibroblasts. Taken together, our results indicate that BRG1 induces tubular senescence by inhibiting autophagy via the Wnt/β-catenin pathway, which ultimately contributes to the development of renal fibrosis.
Topics: Animals; Autophagy; Cell Cycle Proteins; Cellular Senescence; Cytokines; DNA Helicases; Disease Models, Animal; Epithelial Cells; Fibroblasts; Fibrosis; HEK293 Cells; Humans; Kidney Diseases; Kidney Tubules; Male; Mice, Inbred C57BL; Nuclear Proteins; Rats; Transcription Factors; Ureteral Obstruction; Wnt Signaling Pathway; Mice
PubMed: 34318888
DOI: 10.1042/CS20210447 -
Theranostics 2022A deficiency of fatty acid oxidation (FAO) is the metabolic hallmark in proximal tubular cells (PTCs) in renal fibrosis owing to utilization of fatty acids by PTCs as...
A deficiency of fatty acid oxidation (FAO) is the metabolic hallmark in proximal tubular cells (PTCs) in renal fibrosis owing to utilization of fatty acids by PTCs as the main energy source. Lipid accumulation may promote lipotoxicity-induced pathological injury in renal tissue. However, the molecular mechanism underlying lipotoxicity and renal tubulointerstitial fibrosis (TIF) remains unclear. Twist1 has been identified to play an essential role in fatty acid metabolism. We hypothesized that Twist1 may regulate FAO in PTCs and consequently facilitate lipotoxicity-induced TIF. We used hypoxia-induced Twist1 overexpression to incite defective mitochondrial FAO in PTCs, and used renal ischemia-reperfusion or unilateral ureteral obstruction to induce renal injury in mice. We used knockout cells, mice of Twist1, and Harmine to determine the role of Twist1 in FAO and TIF. : Overexpression of Twist1 downregulates the transcription of PGC-1α and further inhibits the expression of FAO-associated genes, such as PPARα, CPT1 and ACOX1. Consequently, reduced FAO and increased intracellular lipid droplet accumulation in a human PTC line (HK-2), leads to mitochondrial dysfunction, and production of increased profibrogenic factors. Twist1 knockout mice with renal injury had increased expression of PGC-1α, which restored FAO and obstructed progression of TIF. Strikingly, pharmacological inhibition of Twist1 by using Harmine reduced lipid accumulation and restored FAO and . Our findings suggest that Twist1-mediated inhibition of FAO in PTCs results in TIF and suggest that Twist1-targeted inhibition could provide a potential strategy for the treatment of renal fibrosis.
Topics: Animals; Down-Regulation; Epithelial Cells; Fatty Acids; Fibrosis; Harmine; Kidney; Kidney Diseases; Mice
PubMed: 35664054
DOI: 10.7150/thno.71722 -
Kidney International Feb 2022Kidney fibrosis is considered the final convergent pathway for progressive chronic kidney diseases, but there is still a paucity of success in clinical application for...
Kidney fibrosis is considered the final convergent pathway for progressive chronic kidney diseases, but there is still a paucity of success in clinical application for effective therapy. We recently demonstrated that the expression of secreted leucine-rich α-2 glycoprotein-1 (LRG1) is associated with worsened kidney outcomes in patients with type 2 diabetes and that LRG1 enhances endothelial transforming growth factor-β signaling to promote diabetic kidney disease progression. While the increased expression of LRG1 was most prominent in the glomerular endothelial cells in diabetic kidneys, its increase was also observed in the tubulointerstitial compartment. Here, we explored the potential role of LRG1 in kidney epithelial cells and TGF-β-mediated tubulointerstitial fibrosis independent of diabetes. LRG1 expression was induced by tumor necrosis factor-α in cultured kidney epithelial cells and potentiated TGF-β/Smad3 signal transduction. Global Lrg1 loss in mice led to marked attenuation of tubulointerstitial fibrosis in models of unilateral ureteral obstruction and aristolochic acid fibrosis associated with concomitant decreases in Smad3 phosphorylation in tubule epithelial cells. In mice with kidney epithelial cell-specific LRG1 overexpression, while no significant phenotypes were observed at baseline, marked exacerbation of tubulointerstitial fibrosis was observed in the obstructed kidneys. This was associated with enhanced Smad3 phosphorylation in both kidney epithelial cells and α-smooth muscle actin-positive interstitial cells. Co-culture of kidney epithelial cells with primary kidney fibroblasts confirmed the potentiation of TGF-β-mediated Smad3 activation in kidney fibroblasts through epithelial-derived LRG1. Thus, our results indicate that enhanced LRG1 expression-induced epithelial injury is an amplifier of TGF-β signaling in autocrine and paracrine manners promoting tubulointerstitial fibrosis. Hence, therapeutic targeting of LRG1 may be an effective means to curtail kidney fibrosis progression in chronic kidney disease.
Topics: Animals; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Endothelial Cells; Fibrosis; Glycoproteins; Humans; Kidney; Leucine; Mice; Smad3 Protein; Transforming Growth Factor beta; Transforming Growth Factor beta1; Transforming Growth Factors; Ureteral Obstruction
PubMed: 34774561
DOI: 10.1016/j.kint.2021.10.023