BPA and neurodevelopmental disorder?


On February 25, 2013 the journal Proceedings of the National Academy of Sciences published an article by Michele Yeo and colleagues on BPA and how it could cause neurodevelopmental disorders. BPA (bisphenol A) is a chemical that has hormone like qualities similar to estrogen. It can be found in the plastic materials in the environment, which can 'leak' into edible items (like water from a water bottle). This ingestion can lead to health problems like cancer and reproductive disorders.

In this paper, they found that BPA can impair central nervous system development. They did experiments to try to figure our how BPA exposure can lead to this using rodents and human nerve cells.

First of all, the development of neurons occurs with chloride presence. When the neurons are developing, there are high levels of chloride, and when the levels drop, the neurons are able to mature. KCC2 is a chloride transport protein that aids in removal of the chloride. It is known that if the level of chloride is not removed, damage can occur to the developing neurons by damaging neural circuits and "preventing" migration of the nerve cells to the appropriate position in the brain.

When BPA exposure is elevated the Kcc2 gene is shut down leading to altered altered levels of chloride in the neurons. This gene is responsible for making KCC2 protein. If that protein can not be made, then chloride regulation will be in trouble with a delay in removal. It was found that MECP2, which is a protein involved in normal brain function could be responsible for shutting down Kcc2 gene. MECP2's abundance increases during exposure of BPA. MECP2 binds to Kcc2 and shuts down the gene.

An interesting finding is that female's neurons were more sensitive to BPA exposure compared to males males. Further studies will be needed to give answers for this interesting finding, and if some sex hormone receptors, like estrogen, are involved with the relation of BPA and KCC2.

In summary, BPA exposure is involved with normal neuron development by effecting Kcc2 gene regulation.

Literature Cited:
Michele Yeo, Ken Berglund, Michael Hanna, Junjie U. Guo, Jaya Kittur, Maria D. Torres, Joel Abramowitz, Jorge Busciglio, Yuan Gao, Lutz Birnbaumer, and Wolfgang B. Liedtke. Bisphenol A delays the perinatal chloride shift in cortical neurons by epigenetic effects on the Kcc2 promoter. PNAS, February 25, 2013 DOI: 10.1073/pnas.1300959110


Wow! I was actually wondering why BPA was considered to be "harmful." Thanks for bringing the answer to me, Heidi! I was mostly wondering because I have heard some people complain about BPA-free Nalgene bottles. They say that the old ones were nearly indestructible, but the newer, BPA-free ones are more fragile and liable to crack if dropped. I suppose it is nice to know the science behind the BPA-free move.

I was using an old Nalgene bottle last summer (one that is not BPA-free). Do you know if I should be concerned about using it? You say that BPA may lead to impairment in nerve development, but do adults need to worry about this? Are my nerves continuously developing?

I didnt even know there was BPA in my water bottle! I had heard that drinking out of the plastic water bottle was bad for you but never understood why. I wonder if the female sensitivity is due to the similarities of BPA to estrogen. I would think it would be the other way around and males would have higher neuron sensitivity. I am deffinitly going to do some research on this myself. Thanks for the awsome blog!

This is really interesting. You mention that this paper finds out how BPA affects neuron development. Does this mean that it is more harmful to developing fetuses, or does it also affect adults?

This is a really cool topic about neuronal development! It's especially interesting to me, as my senior seminar topic for biology is about neurogenesis, so understanding more about what proteins are involved in this process is really valuable information for me! It would be interesting to look into how neurogenesis may be halted by this process of Kcc2 expression shutdown by a BPA-related pathway in conjunction with causes for halted neurogenesis that I have found (specifically in the context of depression and chronic stress). It's always cool to connect different causes for a specific affliction in biology, like neuronal development.

Thanks for writing this! It helped me look at my senior seminar from an additional perspective!

Very nice review of BSA. The molecular details are very interesting. I wonder how much BSA would affect us now that we are pretty old. I use lots of plastic material myself. I guess that may explain the bad grades o_o.

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This page contains a single entry by Heidi published on February 28, 2013 8:13 PM.

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