Rising Stars 2024 #3


Spatially resolved, functional dissection of the spermatogonial stem cell niche

Dr. Haiqi Chen, UT Southwestern Medical Center, USA

Bio: Dr. Chen’s research has been on understanding the genetic regulation of spermatogenesis and male fertility

Working with Dr. C. Yan Cheng at the Population Council, his Ph.D. projects focused on understanding the molecular mechanisms of spermatogenesis and how defects in spermatogenesis lead to male infertility. It was through this Ph.D. training experience that Dr. Chen has begun to appreciate the complex genetic network that influences the various aspects of spermatogenesis. This deep dive into male reproductive biology has made him realize that a lack of proper tools might be one of the major reasons we were unable to systemically dissect such genetic network whose dysregulation can lead to male infertility. This realization underpinned Dr. Chen’s transition to bioengineering during his postdoctoral training with Dr. Fei Chen at the Broad Institute of MIT and Harvard. During that time, Dr. Chen learned to engineer new molecular and genomics tools to dissect biological processes at scale. He invented a DNA editing technology called TRACE, a system capable of continuous, targeted mutagenesis of genomic regions in mammalian cells. He also brought cutting-edging spatial transcriptomics technologies back to the field of male reproductive biology by establishing the first spatial transcriptome atlas of mammalian spermatogenesis.

In his own lab at the UT Southwestern Medical center, Dr. Chen continues to innovate at the intersection of reproductive biology and genomics. His team recently used spatial transcriptomics approaches to reveal the molecular interaction between spermatogonial stem cells and the surrounding microenvironment under both physiological and pathological conditions.

Description: Spermatogonial stem cells (SSCs) in the testis support the lifelong production of sperm. SSCs reside within specialized microenvironments called ‘‘niches,’’ which are essential for SSC self-renewal and differentiation. In this talk, I will discuss our recent efforts to combine spatial transcriptomics, computational analyses, and functional assays to systematically dissect the molecular, cellular, and spatial composition of SSC niches.

Cell fate decisions in sex duct development

Dr. Fei Zhao, University of Wisconsin-Madison, USA

Bio: Dr. Zhao is an assistant professor in the Department of Comparative Biosciences at the University of Wisconsin-Madison. He received his Ph.D. from the University of Georgia under the guidance of Dr. Xiaoqin Ye and postdoctoral training with Dr. Humphrey Yao at the National Institute of Environmental Health Sciences. He published 4 first authored papers and 10 coauthored papers during his PHD training. During his postdoctoral training, he received the NIH Pathway to Independent Award and published his work in Science. Research in Dr. Zhao’ lab is focused on elucidating cellular and molecular mechanisms underlying sexual differentiation of reproductive tracts, which is supported by an NIH R01 grant award. His current trainees have received multiple research awards, including Lalor Foundation Merit Award. In the long run, his group aims to provide fundamental knowledge for the development of better strategies for prevention, diagnosis, and treatment of related disorders of sex development and reproductive diseases. In addition to research, Dr. Zhao teaches reproductive physiology, reproductive toxicology, and developmental genetics in graduate and DVM core courses. He has been a SSR member since 2009. As a trainee SSR member, he coordinated Career Consultation Center, cochaired sessions, and served the trainee representative in Membership and Development Committee; as a regulator member, he served in Publication Committee and currently is a member in Virtual Education Committee.

Description: Alfred Jost’s work in the 1940s laid the foundation of the current paradigm of sexual differentiation of reproductive tracts. Using genetic animal models, ex vivo experiments, and single cell sequencing based technologies, we have gained significant insights into this process, challenging existing dogmas. The yielded knowledge will enable us to not only decipher the fundamental process of dimorphic establishment of reproductive tracts, but also provide insights into how defects and diseases originate from impaired fetal development.

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