Mechanotransduction mechanisms of ovarian aging

Aging affects all tissues and is associated with functional deterioration. Each tissue has specific aging
kinetics, and the female reproductive system is the first to age. Female reproductive aging is associated
with a decrease in oocyte quality and quantity as well as a reduction in the ovarian hormones, which
accelerates women physiologic aging. Reproductive transitions, such as reproductive aging, are a priority
of the Fertility and Infertility branch of the National Institutes of Health, and thus my proposed research is
tightly aligned with the mission of the Eunice Kennedy Shriver National Institute of Child Health and
Human Development. A major contributor to the age-associated reduction of female fertility is the
decrease in oocyte quality due to an increase in oocyte aneuploidy, but our work and others have
demonstrated that other factors, such as the tissue microenvironment, might contribute to the
age-associated reduction in oocyte quality. Physical cues from the tissue environment are major
regulators of cell behavior. In the ovary, stiffness is relevant for normal follicle development but also
associated with pathological conditions. In mice, stiff environments maintain primordial follicles in a
quiescent state. However ovarian stiffness is also a characteristic of polycystic ovarian syndrome in
humans. In my postdoctoral work I pioneered the use of instrumental indentation to measure the
biomechanical properties of the ovary and I found that mice ovaries become stiffer with advanced
reproductive age. During the K99 phase of this award, I utilized in vitro follicle culture and alginate gels to
demonstrate that the age-associated increase in ovarian stiffness impacts folliculogenesis and oocyte
quality. My work on ovarian stiffness and folliculogenesis laid the foundation of this R00 application where
I will test the overarching hypothesis that the age-associated and spatially-dependent increase in ovarian
stiffness creates a physical environment that the follicle senses through the activation of
mechanotransduction pathways. This hypothesis will be tested in three specific aims. First, I will
determine the subcellular features that define ovarian stiffness by performing a 3D spatiotemporal
architecture map of the ovarian stiffness in an age and estrous cycle-dependent manner using a stiffness
mapping system optimized during the K99 phase. Second, I will employ an in vitro system that enables
precise control of the physical environment. In the K99 phase, I discovered that increased levels of

Grant Number: 5R00HD108424-05
NIH Institute/Center: NIH
Principal Investigator: Farners Amargant i Riera