Members & Research

Research

Our goal in this study is to achieve in vitro gametogenesis by reconstructing the cellular environment of gonads, which is fundamental for gamete formation, and thereby develop an experimental system for better understanding gametogenesis and sex determination.。

The research group has already reconstituted ovarian tissue using mouse pluripotent stem cells, establishing a culture system that produces functional oocytes. In this research, we will first reconstruct mouse testicular tissue, which will serve as a roadmap for other animals, and then use this model to recreate the gonadal cellular environment for humans and various animals. Concurrently, we will work with other research groups to establish spermatogonial stem cells from various mammalian species and identify small molecules that affect gametogenesis. These studies aim to enhance our understanding of the gametogenesis process across different species, uncover the causes of infertility, develop techniques for preserving fertility, and improve reproductive performance in both livestock and wild animals.

Research

In principle, we will perform in vitro gametogenesis using wild-type and genetically modified mice to elucidate the molecular mechanisms of spermatogenesis and oogenesis. Based on these technologies, we will develop reproductive assistance techniques to create the next generation using sperm and eggs cultured in vitro. To achieve this, we will send young researchers to Baylor College of Medicine to conduct DNA-encoded small molecule screening. This will identify compounds that induce the proliferation and differentiation of germ cells, promote the fertilization and developmental capacity of sperm and eggs, and control reproductive capacity in animals. Furthermore, compounds that have been confirmed effective in mice will be evaluated for their application in various experimental animals, non-model animals, and primates through joint research with collaborators in Japan, as well as with the University of Pittsburgh in the United States and the Leibniz Institute in Germany.

Research

Development of methods to collect and culture naked mole-rat embryos and to establish their ES cells

The naked mole-rats (NMRs) are the longest-lived rodents, with a maximum lifespan exceeding 40 years. NMRs exhibit resistance to aging and age-related diseases, including cancer, making them an attractive model for investigating mechanisms to prevent aging and cancer. However, due to their eusocial characteristics, where only one queen and a few kings breed in a colony, little progress has been made in reproductive engineering techniques to study these mechanisms. Therefore, we aim to develop fundamental technologies for reproductive engineering, establishing methods for embryo collection and culture, as well as the establishment of embryonic stem (ES) cells.

Research

In this study, we aim to utilize the germline stem (GS) cell culture technique established in mice by Shinohara for the preservation of human and endangered species' spermatogonial stem cells. Dr. Hildebrandt has preserved testicular samples from 285 animals, including rhinos and elephants, while Dr. Orwig has stored human testicular samples. The Orwig lab has also established transplantation techniques for human and primate spermatogonial stem cells, allowing for future infertility treatments through international collaborative research. Additionally, by using Dr. Matzuk's chemical library, we will search for molecules that stimulate the proliferation of GS cells to establish GS cells from humans, primates, and endangered species. Even if culturing is not possible, we aim to develop methods to preserve and recover sperm through the transplantation of testicular fragments.

Research

In this project, we aim to establish a system to induce germ cells and gonadal tissues from pluripotent stem cells in the animal models (rat, rabbit and pig) we have been studying. These animals are well established as experimental animals and have the advantage that we can analyze their germ cell development in embryos and fetuses due to their large litters and easy breeding. In addition, developmental engineering technology for manipulating gametes and embryos under the microscope is well developed, which allows us not only to produce genetically modified animals but also to evaluate the function of the germ cells produced in vitro. By adapting the in vitro gametogenesis technology that has been established in mice to these animal species, we aim to develop a technology that can be used for a variety of animals, including endangered species.

Research

Decades of continuous works in our institute (Leibniz Institute for Zoo & Wildlife Research：Leibniz-IZW) have construct a large number of cell/tissue stocks from various animal tissues (several thousand individuals of more than 300 species including elephant, lion, jaguar, leopard, rhinoceros, kangaroo, fox, wolf, bear, giraffe, zebra, gorilla, chimpanzee). Moreover, we recently established iPS cells from Northern White Rhinoceros, only 2 females left on the earth. Combined with the cutting-edge technology of the Japanese teams, we aim to develop a new line of gametogenesis using our valuable materials. We have accumulating knowledge on reproductive physiology, including monitoring estrus cycle, induction of ovulation, and ovum pick-up, treatment of preimplantation embryo culture, and freeze-thaw of animal tissue followed by cell culture. Under my supervision and with our colleagues, Japanese researchers will be engaged in production of iPS cells and SSCs from endangered animals, induction of germ cells from these iPS cells, and try to develop new technologies to restore reproductive ability, such as transplantation of SSCs.

Research

Research in the Orwig lab focuses on stem cells, germ lineage development, fertility and infertility.　Our progress investigating reproductive function in fertile individuals provides a basis for　understanding the mechanisms of infertility caused by disease, medical treatments, genetics or aging.　Our lab is recognized for its leadership in reproductive stem cell and tissue transplantation and especially for translating those techniques to monkeys on the path to application in the human clinic. We have cryopreserved ovarian tissues and　testicular tissues for over 700 patients since 2011 under experimental protocols. Each patient donates a　portion of their tissue to research. We are committed to using those tissues to responsibly develop next　generation reproductive technologies with this research grant.

Research

Identification of novel agents for fertility protection/enhancement requires the combined application of reproductive biology and modern drug discovery approaches to assess and　interrogate well-validated drug targets. This International Leading Research project is intended　to expand on some initial target identification work by researchers at the Baylor College of　Medicine, with Japanese collaborators, using mouse genetics to identify critical genes for fertility. With additional target validation work, these targets could be investigated using DNA-Encoded　Chemistry Technology (DEC-Tec) in place at Baylor to identify early hits and probe compounds　to provide further chemical validation.

While the Japanese team will generate transgenic, knockout, and knock-in mouse models using the cutting edge genome editing technology and perform mechanistic studies of these models, the BCM team will perform DEC-Tec screens, resynthesize small molecule hits for biochemical and/or biophysical evaluation, and generate chemical probes and tool compounds that enable in vitro functional validation and specificity analyses; and evaluate the metabolic stability and pharmacokinetic properties of optimized hits and perform initial in vivo proof-of-concept studies with drug-like compounds.

Research

Stem cells are pivotal in modeling development and disease, offering immense potential in regenerative medicine and reproductive biology. Our scientific contributions include pioneering novel culture systems and methods for generating new stem cells, aiding both basic and translational research. We have broadened the range of pluripotency states by isolating mouse pluripotent stem cells (PSCs) with unique molecular and phenotypic characteristics from various developmental stages.

These advancements in mouse models have facilitated the creation of PSCs from diverse mammalian species, encompassing humans, non-human primates, and ungulates. Additionally, we have established culture conditions for extraembryonic stem cells, such as trophoblast stem cells (TSCs) and extraembryonic endoderm stem cells (XENs), developed an efficient, versatile blastocyst complementation system for in vivo generation of functional tissues and organs from cultured PSCs and created several stem cell-derived embryo models.