Kidney Week

Abstract: SA-PO925

Cell Type-Specific Effects of Zinc on Human Kidney Cells in Culture

Session Information

• Pathology and Lab Medicine - 2
  October 26, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pathology and Lab Medicine

• 1800 Pathology and Lab Medicine

Authors

• Baalawy, Zakeya Ahmad, King's College London, London, United Kingdom

Zakeya Ahmad Baalawy, MS, MSc, PhD

• Ulker, Zeynep, King's College London, London, United Kingdom

Zeynep Ulker

• Hogstrand, Christer, King's College London, London, United Kingdom

Christer Hogstrand, PhD

• Dockrell, Mark Edward, SWT Institute for Renal Research, London, United Kingdom

Mark Edward Dockrell, MSc, PhD

Background

Zinc is a nutritionally essential trace element for all living organisms; it is required for development, growth, and tissue repair. However zinc excess is harmful and potentially lethal. High zinc has been shown to cause embryological damage in fish. In adult fish Zinc Chloride (ZnCl₂) caused reduction in antioxidant defence systems and neurotoxicity. In man approximately 15% of zinc is cleared through the kidney.
Although CCN2/CTGF (Connective Tissue Growth Factor) is considered pathological particularly in fibrotic diseases, expression of CCN2/CTGF is crucial to embryonic development. CCN2/CTGF knockout mice have multiple skeletal dysmorphisms and raised perinatal lethality.
In this work we examined the effect of sub-lethal zinc concentrations on human embryonic and adult renal cells with a focus on CCN2/CTGF expression.

Methods

Human Embryonic Kidney cells (HEK 293) and adult human primary proximal tubule epithelial cells (PTEC) were treated with a range of concentrations of ZnCl₂. Cell toxicity was measured using CellTox Green Cytotoxicity Assay. Cellular expression of Zinc transport channels (ZIP) was assessed by immunofluorescence microscopy.

Results

ZnCl₂ induced a dose and time dependent increase in HEK 293 cell cytotoxicity, which reached statistical significance at 300 μM at 24h. Primary human PTEC appeared more sensitive to ZnCl₂ with significant cytotoxicity at 100 μM at 24h. ZnCl₂ treatment (20 μM, 24h) significantly reduced CCN2/CTGF expression in HEK 293 cells but had no effect on human primary PTEC CCN2/CTGF expression. Both cell types expressed Zip10 (SLC39A10) zinc channels.

Conclusion

The inhibition of CCN2/CTGF expression in embryonic renal cells may indicate the potential for raised levels of Zinc to induce renal malformation in utero. Zip10 expression has previously been reported in the apical membrane of proximal tubule cells and provides a possible mechanism for zinc entry into the cells however a more comprehensive investigation of Zip protein expression is lacking. An important caveat in the interpretation of our results is that although HEK 293 cells are derived from human embryonic kidney and have an epithelial morphology, the original cells were not fully characterised. Furthermore the cell line is a result of adenovirus transformation.

Funding

• Private Foundation Support