scholarly journals Primary Human Renal Proximal Tubular Epithelial Cells (pHRPTEpiCs): Shiga Toxin (Stx) Glycosphingolipid Receptors, Stx Susceptibility, and Interaction with Membrane Microdomains

Toxins ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 529
Author(s):  
Johanna Detzner ◽  
Anna-Lena Klein ◽  
Gottfried Pohlentz ◽  
Elisabeth Krojnewski ◽  
Hans-Ulrich Humpf ◽  
...  

Tubular epithelial cells of the human kidney are considered as targets of Shiga toxins (Stxs) in the Stx-mediated pathogenesis of hemolytic–uremic syndrome (HUS) caused by Stx-releasing enterohemorrhagic Escherichia coli (EHEC). Analysis of Stx-binding glycosphingolipids (GSLs) of primary human renal proximal tubular epithelial cells (pHRPTEpiCs) yielded globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer) with Cer (d18:1, C16:0), Cer (d18:1, C22:0), and Cer (d18:1, C24:1/C24:0) as the dominant lipoforms. Investigation of detergent-resistant membranes (DRMs) and nonDRMs, serving as equivalents for the liquid-ordered and liquid-disordered membrane phase, respectively, revealed the prevalence of Gb3Cer and Gb4Cer together with cholesterol and sphingomyelin in DRMs, suggesting lipid raft association. Stx1a and Stx2a exerted strong cellular damage with half-maximal cytotoxic doses (CD50) of 1.31 × 102 pg/mL and 1.66 × 103 pg/mL, respectively, indicating one order of magnitude higher cellular cytotoxicity of Stx1a. Surface acoustic wave (SAW) real-time interaction analysis using biosensor surfaces coated with DRM or nonDRM fractions gave stronger binding capability of Stx1a versus Stx2a that correlated with the lower cytotoxicity of Stx2a. Our study underlines the substantial role of proximal tubular epithelial cells of the human kidney being associated with the development of Stx-mediated HUS at least for Stx1a, while the impact of Stx2a remains somewhat ambiguous.

2020 ◽  
Vol 21 (2) ◽  
pp. 391 ◽  
Author(s):  
Patrick C. Baer ◽  
Benjamin Koch ◽  
Janina Freitag ◽  
Ralf Schubert ◽  
Helmut Geiger

Gliflozins are inhibitors of the renal proximal tubular sodium-glucose co-transporter-2 (SGLT-2), that inhibit reabsorption of urinary glucose and they are able to reduce hyperglycemia in patients with type 2 diabetes. A renoprotective function of gliflozins has been proven in diabetic nephropathy, but harmful side effects on the kidney have also been described. In the current project, primary highly purified human renal proximal tubular epithelial cells (PTCs) have been shown to express functional SGLT-2, and were used as an in vitro model to study possible cellular damage induced by two therapeutically used gliflozins: empagliflozin and dapagliflozin. Cell viability, proliferation, and cytotoxicity assays revealed that neither empagliflozin nor dapagliflozin induce effects in PTCs cultured in a hyperglycemic environment, or in co-medication with ramipril or hydro-chloro-thiazide. Oxidative stress was significantly lowered by dapagliflozin but not by empagliflozin. No effect of either inhibitor could be detected on mRNA and protein expression of the pro-inflammatory cytokine interleukin-6 and the renal injury markers KIM-1 and NGAL. In conclusion, empa- and dapagliflozin in therapeutic concentrations were shown to induce no direct cell injury in cultured primary renal PTCs in hyperglycemic conditions.


2001 ◽  
Vol 59 (s78) ◽  
pp. 258-261 ◽  
Author(s):  
Mihaela C. Ignatescu ◽  
Manuela Fodiger ◽  
Josef Kletzmayr ◽  
Christian Bieglmayer ◽  
Walter H. Horl ◽  
...  

2021 ◽  
pp. 1-7
Author(s):  
Zhen Li ◽  
Gang Hou

<b><i>Introduction:</i></b> LincRNA-p21 is predicted to interact with miR-449a, which plays a protective role in cisplatin-induced acute kidney injury (CIA). <b><i>Objective:</i></b> This study aimed to analyze the involvement of lincRNA-p21 in breast cancer patients with CIA. <b><i>Methods:</i></b> Levels of lincRNA-p21 in plasma from CIA, triple negative breast cancer, and control groups were measured by performing RT-qPCR. The potential interaction between lincRNA-p21 and miR-449a was first predicted by RT-qPCR. The relationship between lincRNA-p21 and miR-449a was analyzed by overexpression experiment. <b><i>Results:</i></b> We found that lincRNA-p21 is downregulated in CIA. Dual luciferase activity assay showed that lincRNA-p21 and miR-449a can interact with each other, while overexpression of lincRNA-p21 and miR-449a failed to affect the expression of each other. In human renal proximal tubular epithelial cells (HRPTEpCs), cisplatin led to the upregulated miR-449a but downregulated lincRNA-p21. Interestingly, lincRNA-p21 overexpression led to reduced enhancing effects of miR-449a on the cisplatin-induced apoptosis of HRPTEpCs. <b><i>Conclusion:</i></b> Therefore, lincRNA-p21 is downregulated in CIA and may sponge miR-449a to inhibit cisplatin-induced apoptosis of HRPTEpCs.


2000 ◽  
Vol 279 (4) ◽  
pp. F728-F735 ◽  
Author(s):  
Mingyu Liang ◽  
Anthony J. Croatt ◽  
Karl A. Nath

We examined whether nitric oxide-generating agents influence expression of heme oxygenase-1 (HO-1) in renal proximal tubular epithelial cells, LLC-PK1 cells, and the mechanisms underlying any such effects. In sublytic amounts, the nitric oxide donor sodium nitroprusside induced HO-1 mRNA and protein and HO activity in a dose-dependent and time-dependent fashion; this induction was specific for nitric oxide since the nitric oxide scavenger carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide significantly reduced such induction. The induction of HO activity by sodium nitroprusside, or by another nitric oxide donor, spermine NONOate, was markedly reduced by the iron chelator deferoxamine. Two different thiol-containing agents, N-acetylcysteine and dithiothreitol, blunted such induction of HO by nitric oxide. Downstream products of nitric oxide, such as peroxynitrite or cGMP, were not involved in inducing HO. In higher concentrations (millimolar amounts), sodium nitroprusside induced appreciable cytotoxicity as assessed by lactate dehydrogenase (LDH) release and lipid peroxidation, and both of these effects were markedly reduced by deferoxamine. Inhibition of HO did not affect the cytotoxic effects (measured by LDH release) of sodium nitroprusside. We thus provide the novel description of the induction of HO-1 in renal proximal tubular epithelial cells exposed to nitric oxide donors and provide the first demonstration in kidney-derived cells for the involvement of a redox-based mechanism in such expression. We also demonstrate that, in LLC-PK1 cells exposed to nitric oxide donors, chelatable iron is involved in eliciting the HO-1 response observed at lower concentrations of these donors, and in mediating the cytotoxic effects of these donors when present in higher concentrations.


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