Mitochondrial DNA Insertions into Nuclei of Brain Cells

 

It has recently been discovered that mitochondria have been inserting bits of mitochondrial DNA into the nuclei of brain cells at unusually high rates. During a study on over 1,200 older adults, it was found that the more mitochondrial insertions an individual had, the younger they died. One of the normal functions of mitochondria is to ship their DNA into the nucleus of the cell to integrate it with the nuclear DNA in a process called numtogenesis. Numtogenesis has been commonly observed in reproductive cells and cancer cells but has never before been observed in brain cells. These insertions were studied on blood cells and brain tissue from the cerebellum and the dorsolateral prefrontal cortex, or DLPFC. What they found is that cells from the DLPFC had an average of 15 times as many insertions as the blood cells and 5 times as many insertions as the cerebellar cells. It was also discovered that mitochondrial insertions increased under certain stressors such as drug treatments or genetic mutations.

 

In my opinion, this is something that definitely needs more attention. I believe this is something necessary to further study. This study seems to suggest that numtogenesis is somehow linked to life span. Since the DLPFC has been known to be affected by many age related and neurodegenerative conditions, the higher rate in mitochondrial insertions in the DLPFC could provide a potential explanation or be linked as a factor. With this knowledge we could potentially develop improved treatments for these conditions.

Study suggests autism begins ‘long before birth’

A study was done on the brains of deceased children and it was evidenced that something before birth might cause autism. It was shown that clusters of disorganized brain cells were discovered in tissue samples from brain regions important for regulating social functioning, emotions and communication, which can all be troubling for children with autism. These abnormalities were actually found in 10 of 11 children with autism, but in only 1 of 11 children without the disease. The children’s brains were donated to science after death and causes of death included drowning, accidents, asthma and heart problems. The authors of the study said the clusters, detected with sophisticated lab tests, were probably defects that occurred during the second or third trimesters of pregnancy.

Scientists have been working for decades to find the cause of autism, and they always believe its origins begin before birth. This study was published in the New England Journal of Medicine and scientists suggested that autism may be linked with abnormalities in the brain’s frontal region. The study follows Courchesne-led research suggesting that abnormal gene activity leads to an excessive number of brain cells in the brain’s pre-frontal cortex, located behind the forehead. The studies suggest that in children later diagnosed with autism, genetic networks that regulate prenatal brain cell growth are wrong. Larger studies are needed to determine how common the abnormalities are and what might be the cause.