scholarly journals SARS-CoV-2 Causes Acute Kidney Injury by Directly Infecting Renal Tubules

Author(s):  
Zhaohui Chen ◽  
Junyi Hu ◽  
Lilong Liu ◽  
Rong Chen ◽  
Miao Wang ◽  
...  

Acute kidney injury (AKI) is one of the most prevalent complications among hospitalized coronavirus disease 2019 (COVID-19) patients. Here, we aim to investigate the causes, risk factors, and outcomes of AKI in COVID-19 patients. We found that angiotensin-converting enzyme II (ACE2) and transmembrane protease serine 2 (TMPRSS2) were mainly expressed by different cell types in the human kidney. However, in autopsy kidney samples, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleoprotein was detected in ACE2+ or TMPRSS2+ renal tubular cells, whereas the RNAscope® Assay targeting the SARS-CoV-2 Spike gene was positive mainly in the distal tubular cells and seldom in the proximal tubular cells. In addition, the TMPRSS2 and kidney injury marker protein levels were significantly higher in the SARS-CoV-2-infected renal distal tubular cells, indicating that SARS-CoV-2-mediated AKI mainly occurred in the renal distal tubular cells. Subsequently, a cohort analysis of 722 patients with COVID-19 demonstrated that AKI was significantly related to more serious disease stages and poor prognosis of COVID-19 patients. The progressive increase of blood urea nitrogen (BUN) level during the course of COVID-19 suggests that the patient’s condition is aggravated. These results will greatly increase the current understanding of SARS-CoV-2 infection.

2017 ◽  
Vol 312 (3) ◽  
pp. F502-F515 ◽  
Author(s):  
Yingfeng Shi ◽  
Liuqing Xu ◽  
Jinhua Tang ◽  
Lu Fang ◽  
Shuchen Ma ◽  
...  

Histone deacetylase 6 (HDAC6) inhibition has been reported to protect against ischemic stroke and prolong survival after sepsis in animal models. However, it remains unknown whether HDAC6 inhibition offers a renoprotective effect after acute kidney injury (AKI). In this study, we examined the effect of tubastatin A (TA), a highly selective inhibitor of HDAC6, on AKI in a murine model of glycerol (GL) injection-induced rhabdomyolysis. Following GL injection, the mice developed severe acute tubular injury as indicated by renal dysfunction; expression of neutrophil gelatinase-associated lipocalin (NGAL), an injury marker of renal tubules; and an increase of TdT-mediated dUTP nick-end labeling (TUNEL)-positive tubular cells. These changes were companied by increased HDAC6 expression in the cytoplasm of renal tubular cells. Administration of TA significantly reduced serum creatinine and blood urea nitrogen levels as well as attenuated renal tubular damage in injured kidneys. HDAC6 inhibition also resulted in decreased expression of NGAL, reduced apoptotic cell, and inactivated caspase-3 in the kidney after acute injury. Moreover, injury to the kidney increased phosphorylation of nuclear factor (NF)-κB and expression of multiple cytokines/chemokines including tumor necrotic factor-α and interleukin-6 and monocyte chemoattractant protein-1, as well as macrophage infiltration. Treatment with TA attenuated all those responses. Finally, HDAC6 inhibition reduced the level of oxidative stress by suppressing malondialdehyde (MDA) and preserving expression of superoxide dismutase (SOD) in the injured kidney. Collectively, these data indicate that HDAC6 contributes to the pathogenesis of rhabdomyolysis-induced AKI and suggest that HDAC6 inhibitors have therapeutic potential for AKI treatment.


2017 ◽  
Vol 312 (2) ◽  
pp. F284-F296 ◽  
Author(s):  
David R. Emlet ◽  
Nuria Pastor-Soler ◽  
Allison Marciszyn ◽  
Xiaoyan Wen ◽  
Hernando Gomez ◽  
...  

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.


2021 ◽  
pp. 1-11
Author(s):  
Yue Zhao ◽  
Yue Lang ◽  
Mingchao Zhang ◽  
Shaoshan Liang ◽  
Xiaodong Zhu ◽  
...  

<b><i>Background:</i></b> Mitochondria are dynamic organelles whose structure are maintained by continuous fusion and fission. During acute kidney injury (AKI) progression, mitochondrial fission in renal tubular cells was elevated, characterized by mitochondrial fragmentation. It is tightly associated with mitochondrial dysfunction, which has been proven as a critical mechanism responsible for AKI. However, the initiating factor for the disruption of mitochondrial dynamics in AKI was not well understood. <b><i>Objectives:</i></b> To explore the molecular mechanisms of mitochondrial disorders and kidney damage. <b><i>Methods:</i></b> We established cisplatin-induced AKI model in C57BL/6 mice and proximal tubular cells, and detected the expression of miR-125b by qPCR. Then we delivered miR-125b antagomir after cisplatin treatment in mice via hydrodynamic-based gene transfer technique. Subsequently, we performed luciferase reporter and immunoblotting ­assays to prove miR-125b could directly modulate mitofusin1 (MFN1) expression. We also tested the role of miR-125b in mitochondrial and renal injury through immunofluorescent staining, qPCR, and immunoblotting assays. <b><i>Results:</i></b> miR-125b levels were induced in cisplatin-challenged mice and cultured tubular cells. Anti-miR-125b could effectively alleviate cisplatin-induced mitochondrial fragmentation and kidney injury both in vitro and in vivo. Furthermore, miR-125b could directly regulate MFN1, which is a key regulator of mitochondrial fusion. Our study indicated that miR-125b is upregulated during cisplatin-induced AKI. Inhibition of miR-125b may suppress mitochondrial and renal damage through upregulating MFN1. This study suggests that miR-125b could be a potential therapeutic target in AKI.


PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0126229 ◽  
Author(s):  
Tatsuki Matsumoto ◽  
Madoka Urushido ◽  
Haruna Ide ◽  
Masayuki Ishihara ◽  
Kazu Hamada-Ode ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xuezhong Gong ◽  
Yiru Duan ◽  
Junli Zheng ◽  
Zi Ye ◽  
Tom K. Hei

Contrast-induced nephropathy (CIN) is a leading cause of hospital-acquired acute kidney injury (AKI), but detailed pathogenesis and effectual remedy remain elusive. Here, we tested the hypothesis that contrast media (CM) impaired mitochondrial quality control (MQC) in tubules, including mitochondrial fragmentation and mitophagy, induced systemic inflammation, and intestinal injury. Since we previously demonstrated that the natural antioxidant 2,3,5,6-tetramethylpyrazine (TMP) can be a protectant against CIN, we moreover investigated the involved renoprotective mechanisms of TMP. In a well-established CIN rat model, renal functions, urinary AKI biomarkers, and renal reactive oxygen species (ROS) production were measured. Mitochondrial damage and mitophagy were detected by transmission electron microscopy (TEM) and western blot. The abundance of Drp1 and Mfn2 by western blot and immunohistochemistry (IHC) was used to evaluate mitochondrial fragmentation. TUNEL staining, TEM, and the abundance of cleaved-caspase 3 and procaspase 9 were used to assay apoptosis. We demonstrated that increased mitophagy, mitochondrial fragmentation, ROS generation, autophagy, and apoptosis occurred in renal tubular cells. These phenomena were accompanied by renal dysfunction and an increased excretion of urinary AKI biomarkers. Meanwhile, CM exposure resulted in concurrent small intestinal injury and villous capillary endothelial apoptosis. The abundance of the inflammatory cytokines CCL2 and CCR2 markedly increased in the renal tubules of CIN rats, accompanied by increased concentrations of IL-6 and TNF-α in the kidneys and the serum. Interestingly, TMP efficiently prevented CM-induced kidney injury in vivo by reversing these pathological processes. Mechanistically, TMP inhibited the CM-induced activation of the CCL2/CCR2 pathway, ameliorated renal oxidative stress and aberrant mitochondrial dynamics, and modulated mitophagy in tubular cells. In summary, this study demonstrated novel pathological mechanisms of CIN, that is, impairing MQC, inducing CCL2/CCR2-mediated inflammation and small intestinal injury, and provided novel renoprotective mechanisms of TMP; thus, TMP may be a promising therapeutic agent for CIN.


2020 ◽  
Vol 9 (11) ◽  
pp. 3547
Author(s):  
Ti-I Chueh ◽  
Cai-Mei Zheng ◽  
Yi-Chou Hou ◽  
Kuo-Cheng Lu

The coronavirus 2019 (COVID-19) pandemic has caused a huge impact on health and economic issues. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes cellular damage by entry mediated by the angiotensin-converting enzyme 2 of the host cells and its conjugation with spike proteins of SARS-CoV-2. Beyond airway infection and acute respiratory distress syndrome, acute kidney injury is common in SARS-CoV-2-associated infection, and acute kidney injury (AKI) is predictive to multiorgan dysfunction in SARS-CoV-2 infection. Beyond the cytokine storm and hemodynamic instability, SARS-CoV-2 might directly induce kidney injury and cause histopathologic characteristics, including acute tubular necrosis, podocytopathy and microangiopathy. The expression of apparatus mediating SARS-CoV-2 entry, including angiotensin-converting enzyme 2, transmembrane protease serine 2 (TMPRSS2) and a disintegrin and metalloprotease 17 (ADAM17), within the renal tubular cells is highly associated with acute kidney injury mediated by SARS-CoV-2. Both entry from the luminal and basolateral sides of the renal tubular cells are the possible routes for COVID-19, and the microthrombi associated with severe sepsis and the dysregulated renin–angiotensin–aldosterone system worsen further renal injury in SARS-CoV-2-associated AKI. In the podocytes of the glomerulus, injured podocyte expressed CD147, which mediated the entry of SARS-CoV-2 and worsen further foot process effacement, which would worsen proteinuria, and the chronic hazard induced by SARS-CoV-2-mediated kidney injury is still unknown. Therefore, the aim of the review is to summarize current evidence on SARS-CoV-2-associated AKI and the possible pathogenesis directly by SARS-CoV-2.


2019 ◽  
Vol 35 (4) ◽  
pp. 587-598 ◽  
Author(s):  
Lara Valiño-Rivas ◽  
Leticia Cuarental ◽  
Gabriel Nuñez ◽  
Ana B Sanz ◽  
Alberto Ortiz ◽  
...  

Abstract Background Nlrp6 is a nucleotide-binding oligomerization domain-like receptor (NLR) that forms atypical inflammasomes. Nlrp6 modulates the gut epithelium interaction with the microbiota. However, the expression and function of Nlrp6 in the kidney, a sterile environment, have not been characterized. We explored the role of Nlrp6 in acute kidney injury (AKI). Methods In a transcriptomics array of murine nephrotoxic AKI, Nlrp6 and Naip3 were the only significantly downregulated NLR genes. The functional implications of Nlrp6 downregulation were explored in mice and in cultured murine tubular cells. Results Nlrp6 was expressed by healthy murine and human kidney tubular epithelium, and expression was reduced during human kidney injury or murine nephrotoxic AKI induced by cisplatin or a folic acid overdose. Genetic Nlrp6 deficiency resulted in upregulation of kidney extracellular signal–regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) phosphorylation and more severe AKI and kidney inflammation. In cultured tubular cells, Nlrp6 downregulation induced by specific small interfering RNA resulted in upregulation of ERK1/2 and p38 phosphorylation and chemokine messenger RNA expression and downregulation of the nephroprotective gene Klotho. MAPK inhibition prevented the inflammatory response in Nlrp6-deficient cells. Conclusion Nlrp6 dampens sterile inflammation and has a nephroprotective role during nephrotoxic kidney injury through suppression of MAP kinase activation.


2020 ◽  
Author(s):  
Cheng Ji ◽  
Jiahui Zhang ◽  
Hui Shi ◽  
wanzhu Liu ◽  
Fengtian Sun ◽  
...  

Abstract Background: Acute kidney injury (AKI) was defined by rapid deterioration of renal function, as a common complication in hospitalized patients. Among the recent therapeutic options, mesenchymal stem cells (MSCs) were considered a promising strategy for damaged tissues repair. Platelet rich plasma (PRP) regulates stromal cells to repair tissue damage through the release of growth factors. Here we proposed a possible therapeutic use of human umbilical cord mesenchymal stem cells stimulated by platelet-rich plasma (PRP-MSCs) in a murine model of acute renal injury generated by glycerin injection.Methods: In vivo, we constructed cisplatin-induced acute kidney injury rat models. On day 1 post injury, rat received a tail vein injection of 1×106 MSCs and 1×106 PRP-MSCs. All animals were sacrificed at Day 3 after glycerin injection. Renal function (serum BUN, Creatinine), histopathological structure changes and tubular cells apoptosis were evaluated. In vitro experiment, 50 μmol/L of glycerin treated NRK-52E for 12h were incubated with MSC or PRP-MSC for 24h in transwell co-culture system. Cells were harvested for apoptosis assay, immunofluorescence assay, western blot, and quantitative real-time polymerase chain reaction (qRT-PCR).Results: In vivo and vitro studies confirmed that the PRP induced YAP nucleus expression to promoting the proliferation and reinforces the stemness of MSCs, and stimulated the paracrine exosomes of MSCs by activating AKT/Rab27 signaling pathway to inhibiting the apoptosis of renal tubular cells. Conclusions: Our results revealed a novel potential use of PRP-MSCs as therapeutic strategy for acute kidney injury, highlighting the presence and role of the reno-protective factor PRP-MSCs.


2021 ◽  
Author(s):  
Woo Yeong Park ◽  
Sun-Ha Lim ◽  
Yaerim Kim ◽  
Jin Hyuk Paek ◽  
Kyubok Jin ◽  
...  

Abstract Renal tubular injury caused by oxidative stress and inflammation results in acute kidney injury. Recent research reported that antibiotics may restore deteriorated renal tubules, but the underlying mechanism remains unclear. Therefore, we investigated the efficacy and mechanism of action of antibiotics against renal tubular injury. We screened ciprofloxacin, ceftizoxime, minocycline, and netilmicin and selected ciprofloxacin to examine further because of its low toxicity towards renal tubular cells. We evaluated the effect of ciprofloxacin on cell survival by analyzing apoptosis and autophagy. TUNEL assay results showed that the ciprofloxacin group had less apoptotic cells than the control group. The ratio of cleaved caspase 3 to caspase 3, the final effector in the apoptosis process, was decreased, but the ratio of Bax to Bcl-2 located upstream of caspase 3 was not decreased in the ciprofloxacin group. Therefore, apoptosis inhibition does not occur via Bax/Bcl-2. Conversely, the levels of phosphorylated Bcl-2, and Beclin-1, an autophagy marker, were increased, and that of caspase-3 was decreased in the ciprofloxacin group. This indicates that ciprofloxacin enhanced autophagy, increasing the amount of free Beclin-1 via phosphorylated Bcl-2, and inhibited caspase activity. Therefore, ciprofloxacin might increase renal cell viability through the autophagy activation in acute kidney injury.


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