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Male and female mice have different brain cells

Rare sex-specific neurons are present in the brains of male and female mice

Date:
October 17, 2019
Source:
California Institute of Technology
Summary:
Scientists discover that a brain region known to control sex and violence contains rare cell types that differ in male versus female mice.
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Caltech researchers have discovered rare brain cell types that are unique to male mice and other types that are unique to female mice. These sex-specific cells were found in a region of the brain that governs both aggression and mating behaviors.

The study was done as a collaboration between the laboratory of David Anderson, Seymour Benzer Professor of Biology, Tianqiao and Chrissy Chen Institute for Neuroscience Leadership Chair, Howard Hughes Medical Institute Investigator, and director of the Tianqiao and Chrissy Chen Institute for Neuroscience; and a team at the Allen Institute for Brain Sciences in Seattle, Washington. A paper describing the research appears online on October 17 in the journal Cell.

"The results show that there are differences between male and female mammalian brains at the level of cellular composition as well as gene expression but that those differences are subtle, and their functional significance remains to be explained," says Anderson.

There are many different types of cells within the brain, such as neurons that transmit signals and glial cells that support neural functions. Although all of these cells contain the same set of genes, or genome, the types of cells differ in how they express those genes. As an analogy, one can imagine the genome as an 88-key piano in each cell. Each cell does not use all 88 keys. Therefore, the subset of keys that the cell "plays" determines the type of cell it is.

The hypothalamus is a fundamental region of the brain found in all vertebrates including humans. Previous studies have shown that a specific anatomic subdivision in the hypothalamus, called the ventrolateral subdivision of the ventromedial hypothalamus (VMHvl), contains cells that control aggression and mating behaviors. In these studies, strong stimulation of these neurons in male and female mice immediately caused the animals to become aggressive, even in the absence of any threat. However, weak stimulation caused the mice to begin mating behaviors.

In this new work, led by Caltech graduate student Dong-Wook Kim, the researchers examined gene expression in individual cells in the VMHvl. This was made possible by advanced transcriptomic techniques that can enumerate and identify the RNA transcripts that a cell contains; this information can then be used to classify different cell types. Previous studies were only able to examine 10 percent of the transcripts in each cell, whereas this study looked at a larger proportion of transcripts. The team discovered that there are 17 different types of brain cells in this tiny region alone. What is more, an examination of the patterns of gene expression revealed that some of these 17 cell types are much more abundant in male mice than in females, while others are found only in females.

It was known that different genes are expressed in the two mouse sexes -- indeed, a genetic test can tell you whether a mouse is male or female -- but this is the first discovery of types of cells that are sex-specific in a mammalian brain. Cells are considered to be distinct types when the expression of large clusters of genes varies from cell to cell.

Future work will try to determine the functions of these differing cell types.


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Materials provided by California Institute of Technology. Note: Content may be edited for style and length.


Journal Reference:

  1. Dong-Wook Kim, Zizhen Yao, Lucas T. Graybuck, Tae Kyung Kim, Thuc Nghi Nguyen, Kimberly A. Smith, Olivia Fong, Lynn Yi, Noushin Koulena, Nico Pierson, Sheel Shah, Liching Lo, Allan-Hermann Pool, Yuki Oka, Lior Pachter, Long Cai, Bosiljka Tasic, Hongkui Zeng, David J. Anderson. Multimodal Analysis of Cell Types in a Hypothalamic Node Controlling Social Behavior. Cell, 2019; 179 (3): 713 DOI: 10.1016/j.cell.2019.09.020

Cite This Page:

California Institute of Technology. "Male and female mice have different brain cells." ScienceDaily. ScienceDaily, 17 October 2019. <www.sciencedaily.com/releases/2019/10/191017142809.htm>.
California Institute of Technology. (2019, October 17). Male and female mice have different brain cells. ScienceDaily. Retrieved March 27, 2024 from www.sciencedaily.com/releases/2019/10/191017142809.htm
California Institute of Technology. "Male and female mice have different brain cells." ScienceDaily. www.sciencedaily.com/releases/2019/10/191017142809.htm (accessed March 27, 2024).

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