scholarly journals Cell profiling of mouse acute kidney injury reveals conserved cellular responses to injury

2020 ◽  
Author(s):  
Yuhei Kirita ◽  
Haojia Wu ◽  
Kohei Uchimura ◽  
Parker C. Wilson ◽  
Benjamin D. Humphreys
Keyword(s):  
Acute Kidney Injury ◽  
Proximal Tubule ◽  
Rna Sequencing ◽  
Therapeutic Target ◽  
Kidney Injury ◽  
Cellular Responses ◽  
Acute Injury ◽  
Proximal Tubule Cell ◽  
Tubule Cell ◽  
Single Nucleus

AbstractAfter acute kidney injury (AKI), patients either recover or alternatively develop fibrosis and chronic kidney disease. Interactions between injured epithelia, stroma and inflammatory cells determine whether kidneys repair or undergo fibrosis, but the molecular events that drive these processes are poorly understood. Here, we use single nucleus RNA sequencing of a mouse model of AKI to characterize cell states during repair from acute injury. We identify a distinct proinflammatory and profibrotic proximal tubule cell state that fails to repair. Deconvolution of bulk RNA-seq datasets indicates that this “failed-repair proximal tubule cell” or FR-PTC, state can be detected in other models of kidney injury, increasing in the aging rat kidney and over time in human kidney allografts. We also describe dynamic intercellular communication networks and discern transcriptional pathways driving successful vs. failed repair. Our study provides a detailed description of cellular responses after injury and suggests that the FR-PTC state may represent a therapeutic target to improve repair.Significance StatementSingle nucleus RNA sequencing revealed gene expression changes during repair after acute kidney injury. We describe a small population of proximal tubule cells that fail to repair (FR-PTC). Since this subpopulation expresses abundant pro-inflammatory and profibrotic genes, it may represent a new therapeutic target to improve repair and reduce fibrosis after AKI.

scholarly journals Cell profiling of mouse acute kidney injury reveals conserved cellular responses to injury

2020 ◽  
Vol 117 (27) ◽  
pp. 15874-15883 ◽  
Author(s):  
Yuhei Kirita ◽  
Haojia Wu ◽  
Kohei Uchimura ◽  
Parker C. Wilson ◽  
Benjamin D. Humphreys
Keyword(s):  
Acute Kidney Injury ◽  
Proximal Tubule ◽  
Communication Networks ◽  
Rat Kidney ◽  
Kidney Injury ◽  
Human Kidney ◽  
Cellular Responses ◽  
Acute Injury ◽  
Proximal Tubule Cell ◽  
Tubule Cell

After acute kidney injury (AKI), patients either recover or alternatively develop fibrosis and chronic kidney disease. Interactions between injured epithelia, stroma, and inflammatory cells determine whether kidneys repair or undergo fibrosis, but the molecular events that drive these processes are poorly understood. Here, we use single nucleus RNA sequencing of a mouse model of AKI to characterize cell states during repair from acute injury. We identify a distinct proinflammatory and profibrotic proximal tubule cell state that fails to repair. Deconvolution of bulk RNA-seq datasets indicates that this failed-repair proximal tubule cell (FR-PTC) state can be detected in other models of kidney injury, increasing during aging in rat kidney and over time in human kidney allografts. We also describe dynamic intercellular communication networks and discern transcriptional pathways driving successful vs. failed repair. Our study provides a detailed description of cellular responses after injury and suggests that the FR-PTC state may represent a therapeutic target to improve repair.

scholarly journals Ataxia Telangiectasia and Rad3-Related Activation by DNA Damage Mitigates Maladaptive Repair after Acute Kidney Injury

Nephron ◽  
2021 ◽  
pp. 1-4
Author(s):  
Joseph V. Bonventre
Keyword(s):  
Dna Damage ◽  
Acute Kidney Injury ◽  
Proximal Tubule ◽  
Ataxia Telangiectasia ◽  
Kidney Injury ◽  
Human Kidney ◽  
Acute Injury ◽  
Proximal Tubule Cell ◽  
Cell Renewal ◽  
Healthy State

DNA damage is an important consequence of injury to the proximal tubule. The proximal tubule cell responds to this damage by mounting a DNA damage response (DDR). Two protein kinases, ataxia-telangiectasia mutated (ATM) or ataxia telangiectasia and Rad3-related (ATR), play an important role in this DDR. If efficient, the DDR can lead to repair of the DNA, cell renewal, and return to a healthy state. In many cases, however, especially in the setting of baseline kidney injury, there is incomplete repair. In human chronic kidney disease (CKD) and in human kidney organoids exposed to acute injury, there is increased evidence of DNA damage and activation of ATR. This review focuses on 3 aspects of the DNA damage and response to it: (1) DNA damage and the DDR precipitated by acute injury; (2) protection afforded by the DDR kinase, ATR, in multiple mouse models of acute kidney injury; and (3) downstream effects of genetic inhibition of ATR in the proximal tubule, leading to maladaptive repair, fibrosis, and CKD.

Megalin in acute kidney injury: foe and friend

2014 ◽  
Vol 306 (2) ◽  
pp. F147-F154 ◽  
Author(s):  
Ravikiran Mahadevappa ◽  
Rikke Nielsen ◽  
Erik Ilsø Christensen ◽  
Henrik Birn
Keyword(s):  
Acute Kidney Injury ◽  
Animal Models ◽  
Proximal Tubule ◽  
Essential Role ◽  
Kidney Injury ◽  
Current Evidence ◽  
Renal Protection ◽  
Tubule Cell ◽  
Cellular Protection ◽  
And Function

The kidney proximal tubule is a key target in many forms of acute kidney injury (AKI). The multiligand receptor megalin is responsible for the normal proximal tubule uptake of filtered molecules, including nephrotoxins, cytokines, and markers of AKI. By mediating the uptake of nephrotoxins, megalin plays an essential role in the development of some types of AKI. However, megalin also mediates the tubular uptake of molecules implicated in the protection against AKI, and changes in megalin expression have been demonstrated in AKI in animal models. Thus, modulation of megalin expression in response to AKI may be an important part of the tubule cell adaption to cellular protection and regeneration and should be further investigated as a potential target of intervention. This review explores current evidence linking megalin expression and function to the development, diagnosis, and progression of AKI as well as renal protection against AKI.

scholarly journals Single-cell profiling in COVID-19 associated acute kidney injury reveals patterns of tubule injury and repair in human

2021 ◽  
Author(s):  
David Legouis ◽  
Anna Rinaldi ◽  
Gregoire Arnoux ◽  
Thomas Verissimo ◽  
Jennifer Scotti-Gerber ◽  
...  
Keyword(s):  
Critically Ill ◽  
Critically Ill Patients ◽  
Kidney Injury ◽  
Acute Injury ◽  
State Transitions ◽  
Proximal Tubule Cell ◽  
Hippo Signaling ◽  
Cellular Mechanisms ◽  
Single Nucleus ◽  
Injury And Repair

The cellular mechanisms of kidney tubule repair are poorly characterized in human. Here, we applied single-nucleus RNA sequencing to analyze the kidney in the first days after acute injury in 5 critically ill patients with COVID-19. We identified abnormal proximal tubule cell states associated with injury, characterized by altered functional and metabolic profiles and by pro-fibrotic properties. Tubule repair involved the plasticity of mature tubule cells in a process of cell de-differentiation and re-differentiation, which displayed substantial similarities between mouse and man. In addition, in man we identified a peculiar tubule reparative response determining the expansion of progenitor-like cells marked by PROM1 and following a differentiation program characterized by the sequential activation of the WNT, NOTCH and HIPPO signaling pathways. Taken together, our analyses reveal cell state transitions and fundamental cellular hierarchies underlying kidney injury and repair in critically ill patients.

scholarly journals Single-nuclear transcriptomics reveals diversity of proximal tubule cell states in a dynamic response to acute kidney injury

2021 ◽  
Vol 118 (27) ◽  
pp. e2026684118
Author(s):  
Louisa M. S. Gerhardt ◽  
Jing Liu ◽  
Kari Koppitch ◽  
Pietro E. Cippà ◽  
Andrew P. McMahon
Keyword(s):  
Acute Kidney Injury ◽  
Proximal Tubule ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Specific Gene ◽  
Late Time ◽  
Proximal Tubule Cell ◽  
M Cell ◽  
Cortical Regions

Acute kidney injury (AKI), commonly caused by ischemia, sepsis, or nephrotoxic insult, is associated with increased mortality and a heightened risk of chronic kidney disease (CKD). AKI results in the dysfunction or death of proximal tubule cells (PTCs), triggering a poorly understood autologous cellular repair program. Defective repair associates with a long-term transition to CKD. We performed a mild-to-moderate ischemia–reperfusion injury (IRI) to model injury responses reflective of kidney injury in a variety of clinical settings, including kidney transplant surgery. Single-nucleus RNA sequencing of genetically labeled injured PTCs at 7-d (“early”) and 28-d (“late”) time points post-IRI identified specific gene and pathway activity in the injury–repair transition. In particular, we identified Vcam1+/Ccl2+ PTCs at a late injury stage distinguished by marked activation of NF-κB–, TNF-, and AP-1–signaling pathways. This population of PTCs showed features of a senescence-associated secretory phenotype but did not exhibit G2/M cell cycle arrest, distinct from other reports of maladaptive PTCs following kidney injury. Fate-mapping experiments identified spatially and temporally distinct origins for these cells. At the cortico-medullary boundary (CMB), where injury initiates, the majority of Vcam1+/Ccl2+ PTCs arose from early replicating PTCs. In contrast, in cortical regions, only a subset of Vcam1+/Ccl2+ PTCs could be traced to early repairing cells, suggesting late-arising sites of secondary PTC injury. Together, these data indicate even moderate IRI is associated with a lasting injury, which spreads from the CMB to cortical regions. Remaining failed-repair PTCs are likely triggers for chronic disease progression.

Toll-like receptor 4: An attractive therapeutic target for acute kidney injury

Life Sciences ◽  
2021 ◽  
Vol 271 ◽  
pp. 119155
Author(s):  
Ankush Kumar Jha ◽  
Shobhit Gairola ◽  
Sourav Kundu ◽  
Pakpi Doye ◽  
Abu Mohammad Syed ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Therapeutic Target ◽  
Kidney Injury ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Attractive Therapeutic Target

scholarly journals Proximal tubule-specific overexpression of netrin-1 suppresses acute kidney injury-induced interstitial fibrosis and glomerulosclerosis through suppression of IL-6/STAT3 signaling

2013 ◽  
Vol 304 (8) ◽  
pp. F1054-F1065 ◽  
Author(s):  
Punithavathi Ranganathan ◽  
Calpurnia Jayakumar ◽  
Ganesan Ramesh
Keyword(s):  
Acute Kidney Injury ◽  
Epithelial Cells ◽  
Interstitial Fibrosis ◽  
Kidney Injury ◽  
Transgenic Animals ◽  
Acute Injury ◽  
Tubular Epithelial Cells ◽  
Wild Type ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular

Acute kidney injury-induced organ fibrosis is recognized as a major risk factor for the development of chronic kidney disease, which remains one of the leading causes of death in the developed world. However, knowledge on molecules that may suppress the fibrogenic response after injury is lacking. In ischemic models of acute kidney injury, we demonstrate a new function of netrin-1 in regulating interstitial fibrosis. Acute injury was promptly followed by a rise in serum creatinine in both wild-type and netrin-1 transgenic animals. However, the wild-type showed a slow recovery of kidney function compared with netrin-1 transgenic animals and reached baseline by 3 wk. Histological examination showed increased infiltration of interstitial macrophages, extensive fibrosis, reduction of capillary density, and glomerulosclerosis. Collagen IV and α-smooth muscle actin expression was absent in sham-operated kidneys; however, their expression was significantly increased at 2 wk and peaked at 3 wk after reperfusion. These changes were reduced in the transgenic mouse kidney, which overexpresses netrin-1 in proximal tubular epithelial cells. Fibrosis was associated with increased expression of IL-6 and extensive and chronic activation of STAT3. Administration of IL-6 exacerbated fibrosis in vivo in wild-type, but not in netrin-1 transgenic mice kidney and increased collagen I expression and STAT3 activation in vitro in renal epithelial cells subjected to hypoxia-reoxygenation, which was suppressed by netrin-1. Our data suggest that proximal tubular epithelial cells may play a prominent role in interstitial fibrosis and that netrin-1 could be a useful therapeutic agent for treating kidney fibrosis.

scholarly journals Insulin-like growth factor binding protein 7 and tissue inhibitor of metalloproteinases-2: differential expression and secretion in human kidney tubule cells

2017 ◽  
Vol 312 (2) ◽  
pp. F284-F296 ◽  
Author(s):  
David R. Emlet ◽  
Nuria Pastor-Soler ◽  
Allison Marciszyn ◽  
Xiaoyan Wen ◽  
Hernando Gomez ◽  
...  
Keyword(s):  
Cell Culture ◽  
Acute Kidney Injury ◽  
Kidney Injury ◽  
Human Kidney ◽  
Distal Tubule ◽  
Cell Types ◽  
Tissue Inhibitor Of Metalloproteinases ◽  
Tubule Cell ◽  
Tubule Cells

We have characterized the expression and secretion of the acute kidney injury (AKI) biomarkers insulin-like growth factor binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) in human kidney epithelial cells in primary cell culture and tissue. We established cell culture model systems of primary kidney cells of proximal and distal tubule origin and observed that both proteins are indeed expressed and secreted in both tubule cell types in vitro. However, TIMP-2 is both expressed and secreted preferentially by cells of distal tubule origin, while IGFBP7 is equally expressed across tubule cell types yet preferentially secreted by cells of proximal tubule origin. In human kidney tissue, strong staining of IGFBP7 was seen in the luminal brush-border region of a subset of proximal tubule cells, and TIMP-2 stained intracellularly in distal tubules. Additionally, while some tubular colocalization of both biomarkers was identified with the injury markers kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin, both biomarkers could also be seen alone, suggesting the possibility for differential mechanistic and/or temporal profiles of regulation of these early AKI biomarkers from known markers of injury. Last, an in vitro model of ischemia-reperfusion demonstrated enhancement of secretion of both markers early after reperfusion. This work provides a rationale for further investigation of these markers for their potential role in the pathogenesis of acute kidney injury.

scholarly journals THE POLARITY OF THE PROXIMAL TUBULE CELL IN RAT KIDNEY

1972 ◽  
Vol 54 (2) ◽  
pp. 232-245 ◽  
Author(s):  
Hans-G Heidrich ◽  
Rolf Kinne ◽  
Eva Kinne-Saffran ◽  
Kurt Hannig
Keyword(s):  
Proximal Tubule ◽  
Plasma Membranes ◽  
Specific Activity ◽  
Rat Kidney ◽  
High Specific Activity ◽  
Kidney Cortex ◽  
Proximal Tubule Cell ◽  
Surface Charges ◽  
Tubule Cell ◽  
Rat Kidney Cortex

Two different membrane fractions were obtained from a brush-border fraction of rat kidney cortex by using their different electrical surface charges in preparative free-flow electrophoresis. One membrane fraction contained only morphologically intact microvilli and was characterized by a high specific activity of alkaline phosphatase. The other fraction morphologically resembled classical plasma membranes by possessing junctional complexes and a high Na-K-ATPase activity The contamination of the isolated membrane fractions by other cell organelles was extremely low These two fractions represent the apical (luminal) and the basal (interstitial) area of the renal proximal tubule cell membrane and clearly demonstrate the polarity of this cell.

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