Cell Biology

Cell Biology

All living organisms are made up of basic biological units called cells. Cell biology is the field that studies cells in terms of their structure, function, and behavior.

When applied to reproductive science, cell biology helps us understand how processes such as cell division, differentiation (when cells acquire distinct characteristics), cellular signaling, and other structures and mechanisms influence fertility and the health of offspring. Within the Réseau Québécois en Reproduction (RQR), several research teams are working to better understand these complex mechanisms.

Cell Division

Cell division is a fundamental process in cell biology that allows organisms to grow, renew tissues, and reproduce. There are two types of cell division: mitosis and meiosis. Whether mitotic or meiotic, cell division relies on tightly coordinated molecular events to ensure the faithful duplication of genetic material and its equal distribution to daughter cells.

Jean-Claude Labbé’s team aims to understand how germline stem cells organize themselves to divide in the correct direction, maintaining contact with their immediate environment, known as the "niche." This contact is essential for the cells to both self-renew and generate specialized cells.

Teruko Taketo focuses on meiosis, a type of cell division that occurs only in germ cells and gives rise to eggs and sperm. She studies the errors that can occur at various stages of meiosis and lead to infertility.

Errors in cell division can lead to aneuploidy, a condition where cells inherit an abnormal number of chromosomes. This can disrupt cell function, cause birth defects, or promote the development of cancer. Greg FitzHarris investigates the causes of aneuploidy in oocytes.

Jullien Flynn uses fruit flies (Drosophila) as a model to show that certain repetitive regions of DNA, known as satellite DNA, can cause errors in cell division and affect fertility.

Cell Signaling

Clémence Belleannée’s team studies cell signaling via the primary cilium, a cellular antenna present on most cells in the body. The absence of this structure can impair fertility and contribute to cancers such as prostate cancer.

Étienne Audet-Walsh investigates how sex hormones, such as androgens and estrogens, affect prostate and mammary gland cells. He also studies how endocrine disruptors can interfere with these effects by altering cell function and behavior.

André Tremblay focuses on how breast and ovarian cancers develop. He studies nuclear receptors — proteins inside the cell nucleus that activate specific genes in response to hormonal signals.

Christopher Price’s team examines how hormonal regulation affects the function of ovarian cells (granulosa, theca, and endothelial cells) and follicle development.

To demonstrate that epididymal cells—found in a male reproductive organ called the epididymis—interact with sperm and contribute to fertility, Sylvie Breton uses various cell biology tools, including microscopy. Daniel Cyr also studies the epididymis and investigates how the environment affects cell differentiation and male fertility.

Cell Junctions

Isabelle Plante’s team focuses on cell biology in the context of mammary gland development. They study the interactions between breast cells, which are largely mediated by cell junctions. Disruption of these junctions is associated with breast cancer.

Tight junctions and claudin proteins are the focus of Aimee Ryan’s research. She investigates how these proteins contribute to embryonic development.

Mitochondria

Mitochondria are essential organelles for the functioning of animal cells. They generate the energy and metabolic cofactors necessary for various cellular processes, including reproduction. François Richard studies mitochondria in cumulus cells, which surround the oocyte in the ovary. His goal is to understand how certain molecules called cyclic nucleotides influence mitochondrial activity during oocyte maturation in vitro.

Cell Types

The human body is composed of approximately 250 different cell types. Some are particularly important in reproductive biology.

For example, trophoblasts are essential cells for embryonic development in the uterus during the first days of life. They form the bulk of the placenta. William Pastor’s lab studies these cells to better understand how early placental development is regulated.

Claude Robert studies oocytes, the largest cells in the human body. He is especially interested in the mechanisms that allow oocytes to grow and accumulate the substances needed for embryonic development in the first days after fertilization.

Stem cells are immature cells capable of transforming into various cell types. Serge McGraw’s team uses mouse embryonic stem cells and patient-derived induced pluripotent stem cells (iPSCs) to investigate the mechanisms behind (neuro)developmental disorders in children.

Spermatogonial stem cells are the earliest cells that give rise to sperm in the testes. They multiply to self-renew and produce cells that gradually differentiate into sperm. Makoto Nagano’s team studies these cells to improve fertility preservation techniques for young boys undergoing cancer treatments.

Sperm cells are male reproductive cells that carry the father’s genetic material to the egg. To fulfill this role, they possess unique biological properties. Pierre Leclerc studies these features that enable fertilization.

Leydig cells are part of the male reproductive system. Located in the testes, they produce testosterone, a hormone essential for reproductive function. Jacques J. Tremblay’s research group investigates the development and functions of Leydig cells.

Yojiro Yamanaka is interested in cell shape and how cells change during development. He also studies the evolution and formation of the female reproductive tract in vertebrates.