Applications of Advanced Label-free Imaging and Analysis in Reproductive Biology Studies
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Leena Palotie Auditorium (101A), Aapistie 5A
Topic of the dissertation
Applications of Advanced Label-free Imaging and Analysis in Reproductive Biology Studies
Doctoral candidate
Master of Science Audrey Savolainen
Faculty and unit
University of Oulu Graduate School, Faculty of Biochemistry and Molecular Medicine, Protein and Structural Biology
Subject of study
Biochemistry and molecular biology
Opponent
Professor Juha Kere, MD, PhD, Karolinska Institutet and University of Helsinki
Custos
Assistant Professor Renata Prunskaite-Hyyryläinen, University of Oulu
Applications of Advanced Label-free Imaging and Analysis in Reproductive Biology Studies
Infertility is a global issue, affecting approximately 1.4 billion people. Enduring knowledge gaps in uterine biology, remodeling associated with reproductive cycles and pregnancy, and genes involved in reproduction, coupled with a need for new technology and methods, delay advancements in infertility diagnostics and therapeutic development. This thesis applies label-free advanced imaging and analysis to develop new tools which enable a deeper understanding of processes important in both female and male reproductive biology using mouse models.
Firstly, using higher harmonic generation microscopy, we establish a novel method for label-free, 3D analysis of early implantation sites, named 3DMOUSEneST, which enables imaging the uterine-embryo interaction. We show, for the first time, the 3D rearrangement of fibrillar collagen associated with decidualization and name this structure the “decidual nest”. Furthermore, using mouse models with known fertility defects, we demonstrate that decidual nest volume is a quantifiable measure of decidualization efficacy correlating with theoretical pregnancy progression. Secondly, we apply second harmonic generation (SHG) imaging to profile changes in endometrial fibrillar collagen in the estrous cycle. We reveal dynamic changes, especially in fibrillar collagen borders surrounding endometrial glands. We propose that these borders can serve as a template to reconstruct the endometrial gland morphology, in a method called “SHG casting”. Using a deep learning-based segmentation model for proof-of-principle studies, we reveal that SHG casting is capable of 3D gland reconstruction, comparable to whole-mount immunostaining. Lastly, we characterize Cfap97d1, a previously uncharacterized testis-specific gene. We show that mice without Cfap97d1 are sub-fertile, due to a flagellar motility defect observed with high-speed imaging and caused by loss of flagellar microtubule doublets. Based on our data, we conclude that Cfap97d1 is important for flagellar axoneme maintenance and, consequently, male fertility in mice.
Overall, by using advanced imaging, the work in this thesis reveals new insights into uterine fibrillar collagen remodeling associated with early pregnancy and the estrous cycle important for female fertility, and sperm flagellar bending motility, important for male fertility, and validates novel methods facilitating future discoveries.
Firstly, using higher harmonic generation microscopy, we establish a novel method for label-free, 3D analysis of early implantation sites, named 3DMOUSEneST, which enables imaging the uterine-embryo interaction. We show, for the first time, the 3D rearrangement of fibrillar collagen associated with decidualization and name this structure the “decidual nest”. Furthermore, using mouse models with known fertility defects, we demonstrate that decidual nest volume is a quantifiable measure of decidualization efficacy correlating with theoretical pregnancy progression. Secondly, we apply second harmonic generation (SHG) imaging to profile changes in endometrial fibrillar collagen in the estrous cycle. We reveal dynamic changes, especially in fibrillar collagen borders surrounding endometrial glands. We propose that these borders can serve as a template to reconstruct the endometrial gland morphology, in a method called “SHG casting”. Using a deep learning-based segmentation model for proof-of-principle studies, we reveal that SHG casting is capable of 3D gland reconstruction, comparable to whole-mount immunostaining. Lastly, we characterize Cfap97d1, a previously uncharacterized testis-specific gene. We show that mice without Cfap97d1 are sub-fertile, due to a flagellar motility defect observed with high-speed imaging and caused by loss of flagellar microtubule doublets. Based on our data, we conclude that Cfap97d1 is important for flagellar axoneme maintenance and, consequently, male fertility in mice.
Overall, by using advanced imaging, the work in this thesis reveals new insights into uterine fibrillar collagen remodeling associated with early pregnancy and the estrous cycle important for female fertility, and sperm flagellar bending motility, important for male fertility, and validates novel methods facilitating future discoveries.
Last updated: 21.5.2025