Cylindrospermopsin impairs tubular transport function in kidney cells LLC-PK1

Area of Science:

• Toxicology
• Nephrology
• Cell Biology

Background:

• Cylindrospermopsin (CYN) is a cyanotoxin implicated in human poisoning, primarily affecting the kidneys.
• CYN exposure in mice causes tubular damage, indicated by proteinuria and elevated tubular enzyme excretion.
• The precise mechanisms underlying CYN-induced nephrotoxicity remain largely unelucidated.

Purpose of the Study:

• To investigate the effects of CYN on renal tubular cells (LLC-PK1) at the cellular level.
• To elucidate the mechanisms of CYN-induced nephrotoxicity, including cell death, transport function, and toxin internalization.
• To evaluate the impact of varying CYN concentrations (0.1, 0.5, 1.0 μg/mL) on kidney tubule cells.

Main Methods:

• Cell death was assessed using flow cytometry.
• Albumin uptake was measured via fluorescence analysis.
• Na+/K+-ATPase activity was determined using a colorimetric method.
• Gene expression related to tubular transport was analyzed by RT-qPCR.
• CYN internalization was quantified using ELISA.

Main Results:

• CYN induced necrosis in LLC-PK1 cells across all tested concentrations.
• Albumin uptake was significantly reduced by CYN exposure.
• CYN downregulated the expression of megalin and dab2, key proteins in albumin endocytosis.
• Evidence suggests CYN is internalized by renal tubular cells through receptor-mediated endocytosis.
• CYN disrupted tubular cell transport and function in the studied cell model.

Conclusions:

• CYN directly induces necrosis and impairs albumin uptake in renal tubular cells.
• The toxin interferes with crucial transport proteins and functions within kidney tubules.
• Receptor-mediated endocytosis is a likely pathway for CYN entry into renal cells, contributing to its nephrotoxicity.