Homem Lab | Mitochondria plays a crucial role in regulation of stem cells and is involved in regulation of ovarian cell architecture

foto catarina homem_marcia garcez
[Left to right: Patrícia Grácio, Catarina Homem, Márcia Garcez]

Márcia Garcez, PhD Student from the Proliferation and Fate Regulation of Stem Cells Lab led by Catarina Homem, published an article in the journal Frontiers in Cell and Developmental Biology entitled "Mitochondrial dynamics in the Drosophila ovary regulates germ stem cell number, cell fate and female fertility" (full article here).

In brief, Márcia Garcez and Catarina Homem talk about this article:

What discoveries led you to the research described in your publication?
During organism development, stem cells (SC) have the essential role of generating all the cell types that form our body. In adulthood, they are scarce but crucial for the maintenance and regeneration of tissues throughout the lifetime. It is thus of extreme importance to understand how SCs are regulated.
In the last years, several studies have highlighted the important role of energy metabolism in the regulation of SC fate and proliferation. Mitochondria, as major sources of energy, are important organelles for cell metabolism adapting their shape and, consequently, their function to meet cellular requirements. However, it remains unclear how metabolism intersects with mitochondrial morphology and function during SC regulation.
In Drosophila, germ stem cells (GSCs) are among the few SCs present in the adult fly and have the essential task of generating gametes. Interestingly, in the female germline mitochondria have additional importance since it is the only source of mitochondria inherited by the progeny. Previous studies have shown that mitochondria morphology is important in male GSC maintenance and during female GSC aging. However, the role of mitochondria in female GSC homeostasis was poorly understood.

What were you trying to understand and what is the main discovery of this work?
In this work, we addressed how metabolism intersects with mitochondrial morphology and function, in the context of female germ stem cells regulation.
Using as a model the Drosophila female germline, we found that mitochondria morphology is an important factor to ensure the maintenance of GSCs. When we modulated mitochondria shape by interfering with mitochondrial regulators, the number of GSC found in the ovaries were decreased. Additionally, we observed a similar decrease in GSC number when we interfere with key metabolic process by which energy is generated, named oxidative phosphorylation. These results are interesting because they indicate that the mitochondrial morphology and the levels of oxidative phosphorylation function together to regulate GSC maintenance.
We also found that interfering with mitochondria morphology leads to defective ovary structure having as consequence a strong reduction in the number and quality of the eggs produced, compromising female fertility.
Overall, our work highlights the crucial role of mitochondria morphology in the regulation of stem cells and additionally sheds light on a non-explored role for mitochondria in the regulation of ovarian cell architecture.

What questions remain to be asked?
It is still important to understand how mitochondria are differentially regulated in germ stem cells versus other cell types. Moreover, at the mechanistic level, it will be interesting to learn how mitochondria regulate the morphology of the ovaries, a role for mitochondria which had not yet been described and indicates a new role for these organelles.

Find out more about Fate Regulation of Stem Cells Lab.

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