Single-walled carbon nanotubes alter cytochrome c electron transfer and modulate mitochondrial function
Xiaowei Ma1, Li-Hua Zhang, Li-Rong Wang
1Laboratory of Nanomedicine and Nanosafety, Division of Nanomedicine and Nanobiology, National Center for Nanoscience and Technology, China.
ACS Nano
|November 23, 2012
Summary
Single-walled carbon nanotubes (SWCNTs) disrupt mitochondria by altering cytochrome c (Cyt c) redox activity and electron transfer. This impacts cellular respiration and has implications for SWCNT biomedical applications.
Area of Science:
- Biomedical Nanotechnology
- Cellular Respiration
- Molecular Interactions
Background:
- Single-walled carbon nanotubes (SWCNTs) offer promise for biomedical uses, but their intracellular effects remain unclear.
- Cytochrome c (Cyt c) is vital for mitochondrial energy production and cellular processes.
- Understanding SWCNT interactions with intracellular components like Cyt c is crucial.
Purpose of the Study:
- To investigate the impact of SWCNTs on Cyt c and mitochondrial function.
- To elucidate the mechanism behind SWCNT-induced changes in Cyt c redox activity.
- To assess the consequences for cellular respiration.
Main Methods:
- Cell treatment with SWCNTs using human epithelial KB cells.
- Spectroscopic analysis (UV-Vis, Circular Dichroism) to study Cyt c.
- Electron Spin Resonance (ESR) spectroscopy to measure electron transfer.
- Mitochondrial membrane potential and oxygen uptake assays.
Main Results:
- SWCNTs significantly decreased mitochondrial membrane potential and oxygen uptake.
- SWCNTs induced pH-dependent deoxidation of Cyt c, confirmed by absorption peak at 550 nm.
- Circular dichroism revealed pH-dependent conformational changes in Cyt c, enhancing SWCNT association and Cyt c reduction.
- SWCNTs disturbed Cyt c electron transfer, impacting mitochondrial respiration.
Conclusions:
- SWCNTs affect Cyt c redox activity via attenuated electron transfer and conformational changes.
- These alterations disrupt mitochondrial respiration in SWCNT-treated cells.
- Findings provide novel insights into SWCNT-mitochondria interactions and implications for biomedical applications.
Related Concept Videos
01:45Mitochondrial Membranes
A single mitochondrion is a bean-shaped organelle enclosed by a double-membrane system. The outer membrane of mitochondria is smooth and contains many porins - the integral membrane transporters. Porins enable free diffusion of ions and small uncharged molecules through the outer mitochondrial membrane but limit the transport of molecules larger than 5000 Daltons. Further, the outer mitochondrial membrane forms a unique structure called membrane contact sites with other subcellular organelles,...
01:46Electron Transport Chain: Complex I and II
The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
ROS generation is regulated and maintained at moderate levels necessary...
01:28The Inner Mitochondrial Membrane
The inner mitochondrial membrane is the primary site of ATP synthesis. The inner membrane domain that forms a smooth layer adjacent to the outer membrane is called the inner boundary membrane. This domain contains membrane transporters that drive metabolites in and out of the mitochondria. In contrast, the inner membrane network that invaginates into the matrix space is called the cristae membrane. This domain accounts for principle mitochondrial function as it accommodates the protein...
01:37Mitochondria
Mitochondria are eukaryotic cellular organelles that are known to produce energy through a process called oxidative phosphorylation. Besides their primary function, mitochondria are involved in various cellular processes, including cell growth, differentiation, signaling, metabolism, and senescence. Age-related changes cause a decline in mitochondrial quality and integrity due to increased mitochondrial mutations and oxidative damage. Thus, aging can severely impact mitochondrial functions,...
01:30The Electron Transport Chain
The electron transport chain or oxidative phosphorylation is an exothermic process in which free energy released during electron transfer reactions is coupled to ATP synthesis. This process is a significant source of energy in aerobic cells, and therefore inhibitors of the electron transport chain can be detrimental to the cell's metabolic processes.
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...