Zinc cytotoxicity induces mitochondrial morphology changes in hela cell line

Area of Science:

• Cell Biology
• Mitochondrial Biology
• Metal Ion Homeostasis

Background:

• Free zinc (Zn²⁺) is crucial for cellular functions but tightly regulated.
• Zinc overload, often occurring in unhealthy cellular conditions like hypoxia, can induce cellular and mitochondrial stress.
• Mitochondrial morphology shifts from a healthy tubular to a fragmented, circular shape under stress.

Purpose of the Study:

• To investigate if zinc overload directly causes abnormal mitochondrial morphology.
• To analyze the impact of exogenous zinc application on mitochondrial shape in HeLa cells.
• To determine if chelating agents can reverse zinc-induced mitochondrial morphological changes.

Main Methods:

• HeLa cells were treated with varying concentrations of zinc chloride (1–200 µM) and pyrithione (10 µM).
• Mitochondrial morphology was quantified using the Mito-Morphology micro plugin in ImageJ.
• The effect of the metal ion chelator TPEN on zinc-treated cells was assessed.

Main Results:

• Exogenous zinc induced a dose-dependent shift in mitochondrial morphology from tubular to fragmented and circular.
• Abnormal mitochondrial morphology was observed even at low micromolar concentrations of zinc.
• TPEN treatment effectively reversed the zinc-induced abnormal mitochondrial morphology.

Conclusions:

• Zinc overload directly contributes to mitochondrial stress and abnormal morphology.
• Altered mitochondrial morphology due to zinc overload may be a precursor to cell death.
• Targeting zinc levels could be a therapeutic strategy for conditions involving mitochondrial dysfunction.