Obesity, infertility and oxidative stress in mouse egg cells

August 16, 2018

Excessive body fat is associated with negative effects on female fertility and pregnancy. In mice, maternal obesity impairs proper development of egg precursor cells called oocytes. In a recent paper published in Molecular & Cellular Proteomics, Qiang Wang and colleagues at the State Key Laboratory of Reproductive Medicine in China describe the link between poor oocyte development and oxidative stress in mice.

The authors used proteomics to compare oocytes from mice fed a high-fat diet, which became obese, with normally fed mice. When they compared protein expression level in oocytes from these mice, they found numerous changes in mitochondrial and redox proteins, In particular, a mitochondrial protein called TP53-inducible glycolysis and apoptosis regulator, or TIGAR, was expressed at a lower level in oocytes from mice on a high-fat diet.

To develop into egg cells that can be fertilized, oocytes need to complete a type of cell division known as meiosis. Researchers found evidence that TIGAR may play a role in the meiotic spindle, a cell structure that coordinates the movements of DNA in the oocyte. When the researchers reduced TIGAR level using siRNA, they found that oocytes were much more likely to divide unevenly, indicating problems with meiosis that could prevent production of a viable egg cell in obese mice.

Eggs lacking TIGAR also had significantly higher levels of reactive oxygen species, a byproduct of cellular respiration. The researchers traced this result to TIGAR's known role in generating antioxidants. When TIGAR was depleted in mouse oocytes either by feeding or RNA interference, reactive oxygen species were higher, which activated a cellular quality-control pathway called autophagy.

Wang and colleagues demonstrated that the ROS production that TIGAR suppresses is a driving force for downstream autophagy, providing a link between TIGAR-mediated redox homeostasis and cell development. This study provides evidence of the direct effects of maternal obesity on the quality of oocyte development and implicates TIGAR in oocyte maturation in mice. The finding may have implications for infertility treatments for obese women.
-end-


American Society for Biochemistry and Molecular Biology

Related Mitochondrial Articles from Brightsurf:

Single-cell analysis provides new insights into mitochondrial diseases
Investigators led by a team at Massachusetts General Hospital (MGH) have made discoveries at the single cell level to uncover new details concerning mitochondrial diseases-- inherited disorders that interfere with energy production in the body and currently have no cure.

Major cause of rare genetic mitochondrial disease identified
An international study led by the Murdoch Children's Research Institute (MCRI) has given hope to families of children born with a fatal heart muscle disease caused by faulty cell machinery.

How to precisely edit mitochondrial DNA
A gene editing tool based on a bacterial toxin can make precise changes to mitochondrial DNA inside cells.

New molecular tool precisely edits mitochondrial DNA
The precision editing technologies that have revolutionized DNA editing in the cell nucleus have been unable to reach the mitochondrial genome.

First simulation of a full-sized mitochondrial membrane
Scientists from the University of Groningen have developed a method that combines different resolution levels in a computer simulation of biological membranes.

Cell biology -- maintaining mitochondrial resilience
Mitochondria cannot autonomously cope with stress and must instead call on the cell for help.

Muscle weakness after sepsis linked to mitochondrial dysfunction
Damage to energy-producing mitochondria may underlie prolonged muscle weakness following a sepsis-like condition in mice, according to a new study published today in eLife.

Increasing food intake by swapping mitochondrial genomes
To uncover the relationship between variation in genes and phenotypic diversity, geneticists use a set of fully sequenced fruit-fly genomes.

Structure of a mitochondrial ATP synthase
SciLifeLab researchers Alexander Mühleip and Alexey Amunts from Stockholm University solved the structure of a mitochondrial ATP synthase with native lipids.

New research tool for studying mitochondrial disorders and aging
Researchers at Karolinska Institutet in Sweden have developed a new research tool for studying how mitochondrial protein synthesis is affected by disease, pharmaceuticals, ageing and different physiological situations such as exercise and diet.

Read More: Mitochondrial News and Mitochondrial Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.