Longer description of your proposed project

Women over 35 experience a dramatic loss in fertility and a higher incidence of miscarriages. Most of these issues occur at the stage where the developing embryo implants into the mother’s uterus. Because there is a global trend towards a higher average maternal age of childbirth, I seek to understand the origin of these defects to build therapeutic interventions that improve In Vitro Fertilization (IVF) success. Specifically, my work will address whether we can 1) rejuvenate maternally aged embryos to restore implantation and 2) screen embryos to identify those that are most likely to lead to a full-term pregnancy. These two interventions will require a more detailed understanding of the specific defects in the development of embryos from older women, which is a research question that is completely overlooked in Reproductive Science. I study this process in mice, which like humans exhibit dramatic age-related decreases in female fertility. I am the first scientist to use live-cell microscopic analysis of early embryo development using aged females. By careful staging of each key developmental step, I have found that the very earliest defect in embryos from older mothers is improper tissue formation for the cells that will go on to form the placenta versus the embryo proper. This defect appears to originate from increased embryo mechanics, or heightened embryo stiffness, that leads to improper activation of key downstream molecules like the cell fate regulator, YAP. Excitingly, I have recently developed tools to manipulate the activation of YAP and other embryonic regulators with light using a technique called optogenetic activation. This experimental manipulation will enable me to use light at certain embryonic timepoints to restore the normal pattern of YAP regulation, recover primitive-placental tissue differentiation, and potentially rejuvenate the embryos from aged females to a more youthful state. The goal of this intervention is to increase percentage of embryos capable of uterine implantation. My previous work suggests that the embryos from aged mothers are mechanically “stiffer.” This could explain age-related miscarriages, in that embryos are unable to fully attach and invade into the mother’s uterus. Yet this theory presents an exciting opportunity to develop a novel force classification of embryo stiffness as it relates to implantation potential. I am now developing these tools, which can be implemented in parallel to current IVF protocols, using frequently acquired embryo biopsies. The isolated embryonic tissue will be functionally tested to characterize force profiles of the future implanting tissues, thereby identifying the small proportion of embryos from aged females that are most amenable to implantation and live birth. Force profile classification represents a novel screening approach that can visualize cell attachment and quantify force production. These platforms can dramatically transform IVF procedures not just for older women, but also frequently infertile women and those participating in multiple IVF cycles. I want to translate these data to the human embryo in collaboration with IVF clinics in attempt to increase the efficiency of embryo selection. My work aims to ensure IVF success in terms of accessibility, cost, time, and risk to the mother and the future baby. My goal is to lessen an additional burden to such biological constraints, in that the economics of IVF procedures creates significant reproductive inequity. Improving procedural success rates is paramount to lowering IVF costs, further lowering the barriers of entry for socioeconomically challenged and minority parents that are historically excluded from assisted reproductive technologies.

Describe why you think you're qualified to work on this

In my graduate work, I sought to deepen my understanding of epithelial tissue topology during embryo development, as tissues often undergo complex morphogenetic movements to template organismal shape. Here, tissue rearrangements rely upon precise signaling of contractility in space and time. The field's predominant model was that contractility is sufficient to shorten cell-cell contact lengths within tissues to drive tissue shape changes. To test this hypothesis, I created the first successful synthetic system targeting contractility exogenously to cell contacts with light to thus examine tissue shape in cell culture. With experiments and theory, we challenged the widely accepted model and instead supported a new theory that cell contacts are adaptive and act like silly putty (a-c). Here, tissues can sense its contraction to either stabilize new tissue shapes or return to its original shape to maintain tissue homeostasis.

a. *Staddon, M, Cavanaugh, K, et al., (2019) Mechanosensitive junction remodeling promotes robust epithelial morphogenesis. Biophys J. https://doi.org/10.1016/j.bpj.2019.09.027

b. *Cavanaugh, K, et al., (2020) RhoA mediates epithelial cell shape changes via mechanosensitive endocytosis. Developmental Cell 52 1-15. https://doi.org/10.1016/j.devcel.2019.12.002

c. Cavanaugh, K, et al., (2020) Adaptive Viscoelasticity of Epithelial Cell Junctions: From Models to Methods. Current Opinions in Genetics and Development, 2020 63:86-94 https://doi.org/10.1016/j.gde.2020.05.018

*highlighted in The Restless Cell (2023), by Christina Hueschen and Rob Phillips

In my postdoctoral work, I sought to apply my knowledge of tissue mechanics and skills in synthetic biology to address the concept of mechanical signal transduction during mouse development. I moved to UCSF to work in collaboration with Orion Weiner and Diana Laird studying how reproductive aging diminishes mechanotransduction for spontaneous abortions during implantation. Dr. Weiner is a world leading expert on cell mechanics and synthetic optogenetic approaches in driving cell fate decisions. Dr. Laird, a member of UCSF’s Bakar Aging Research Institute, specializes in human and mouse reproductive longevity with a particular focus on oocyte genetics. By synergizing between these labs, I am pioneering a new area of research examining the mechanical basis of morphogenetic defects that arise with reproductive aging. I used high-resolution light-sheet imaging to quantify morphogenetic stages throughout the entirety of pre-implantation development of embryos from young and maternally aged mothers. I combined this with precise mechanical measurements of embryo stiffness using Micropipette Aspiration tools, pairing these data with computational force inference modeling and in vitro synthetic implantation assays that harness Traction Force Microscopy to quantify embryo-substrate output force. By interfacing biophysics and reproductive health, I uncovered novel mechanical defects during key developmental stages in maternally aged embryos, whose defects propagate to altered fate acquisition of the implanting tissues, ultimately impairing implantation mechanics (a).

a. Cavanaugh, K, Rao, S, Phillips, E, Doherty, C, Turlier, H, Oakes, P, Laird, D, & Weiner, O. (in preparation) Embryos from maternally aged mothers exhibit precocious compaction and attenuated trophectoderm specification.

Other ways I can learn about you

https://twitter.com/cavankatenaugh; https://orcid.org/0000-0001-9293-0296

How much money do you need?

This is a complicated answer. With $20,000-30,000, I can purchase the necessary pieces of equipment and reagents to extend my current data into the next phase for clinical translation. However, my lab currently studies immune cell migration and is equipped for optogenetic activation of small immune cells. Since this is an entirely new project and system in the lab, we don’t have any current funding dedicated to this specific project. In the least, I am hoping to add certain pieces of equipment suitable for optimizing our current optogenetic setup for use with the mouse embryo. This requires new microscope objective to co-opt our current microscope ($5,000) and incubator-safe optogenetic plate for high-throughput testing of light patterns ($6,000). Additional equipment is a UV crosslinker for implantation assays ($3,500) and general reagents/consumables for making substrates suitable for in vitro implantation experiments ($5,000). With $100,000, I can place a down payment on a microscope that was built for high resolution imaging of the mouse embryo (capable of imaging every 2 minutes for 48 hours!) that also has built-in optogenetic capabilities for subcellular light activation. This downpayment would enable us to built the microscope and pay it off yearly instead of a typical lump sum taken straight from other grants from the lab. Any amount of funds will help in moving my project to the next phase.

Links to any supporting documents or information

Happy to include more detailed grant proposals if needed

Estimate your probability of succeeding if you get the amount of money you asked for

I am highly confident that, with ACX funds, I can make substantial progress in translating my tools to the clinic. My idea of success is to produce enough data showing the feasibility of these platforms in rescuing or predicting implantation efficiency. Funds for equipment costs will be essential to generate sufficient preliminary data to entice IVF partners. If my optogenetic framework is successful, showing increased rejuvenation and implantation success with light-induced YAP rescue, this may indicate that embryos from maternally aged embryos are indeed capable of implanting. This would suggest other potential routes for success, such as pharmacologically modifying embryo stiffness to compensate for impaired placental differentiation. With an established embryo biopsy force classifier, I can collaborate with IVC clinics and the Endocrinology Department at UCSF to use frozen human embryo biopsies. These samples would reveal which embryos were transferred to the mother and which embryos were carried to term. These funds will be instrumental in starting the journey from bench to bedside, and I consider these funds the prerequisite for success in clinical translation.