Browsing by Author "Heller, Stefan"

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    Hair follicle development in mouse pluripotent stem cell-derived skin organoids
    (Elsevier, 2018-01-02) Lee, Jiyoon; Boescke, Robert; Tang, Pei-Ciao; Hartman, Byron H.; Heller, Stefan; Koehler, Karl R.; Otolaryngology -- Head and Neck Surgery, School of Medicine
    The mammalian hair follicle arises during embryonic development from coordinated interactions between the epidermis and dermis. It is currently unclear how to recapitulate hair follicle induction in pluripotent stem cell cultures for use in basic research studies or in vitro drug testing. To date, generation of hair follicles in vitro has only been possible using primary cells isolated from embryonic skin, cultured alone or in a co-culture with stem cell-derived cells, combined with in vivo transplantation. Here, we describe the derivation of skin organoids, constituting epidermal and dermal layers, from a homogeneous population of mouse pluripotent stem cells in a 3D culture. We show that skin organoids spontaneously produce de novo hair follicles in a process that mimics normal embryonic hair folliculogenesis. This in vitro model of skin development will be useful for studying mechanisms of hair follicle induction, evaluating hair growth or inhibitory drugs, and modeling skin diseases., Lee at el. describe a defined in vitro 3D culture system that generates skin organoids from mouse pluripotent stem cells. The skin organoids contain self-organized skin layers and skin appendages including hair follicles, sebaceous glands, and adipocytes.,
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    Hair-bearing human skin generated entirely from pluripotent stem cells
    (Springer Nature, 2020-06) Lee, Jiyoon; Rabbani, Cyrus C.; Gao, Hongyu; Steinhart, Matthew R.; Woodruff, Benjamin M.; Pflum, Zachary E.; Kim, Alexander; Heller, Stefan; Liu, Yunlong; Shipchandler, Taha Z.; Koehler, Karl R.; Otolaryngology -- Head and Neck Surgery, School of Medicine
    The skin is a multilayered organ, equipped with appendages (that is, follicles and glands), that is critical for regulating body temperature and the retention of bodily fluids, guarding against external stresses and mediating the sensation of touch and pain1,2. Reconstructing appendage-bearing skin in cultures and in bioengineered grafts is a biomedical challenge that has yet to be met3-9. Here we report an organoid culture system that generates complex skin from human pluripotent stem cells. We use stepwise modulation of the transforming growth factor β (TGFβ) and fibroblast growth factor (FGF) signalling pathways to co-induce cranial epithelial cells and neural crest cells within a spherical cell aggregate. During an incubation period of 4-5 months, we observe the emergence of a cyst-like skin organoid composed of stratified epidermis, fat-rich dermis and pigmented hair follicles that are equipped with sebaceous glands. A network of sensory neurons and Schwann cells form nerve-like bundles that target Merkel cells in organoid hair follicles, mimicking the neural circuitry associated with human touch. Single-cell RNA sequencing and direct comparison to fetal specimens suggest that the skin organoids are equivalent to the facial skin of human fetuses in the second trimester of development. Moreover, we show that skin organoids form planar hair-bearing skin when grafted onto nude mice. Together, our results demonstrate that nearly complete skin can self-assemble in vitro and be used to reconstitute skin in vivo. We anticipate that our skin organoids will provide a foundation for future studies of human skin development, disease modelling and reconstructive surgery.
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    Modulation of Wnt Signaling Enhances Inner Ear Organoid Development in 3D Culture
    (Plos, 2016-09-08) DeJong, Rachel E.; Liu, Xiao-Ping; Deig, Christopher R.; Heller, Stefan; Koehler, Karl R.; Hashino, Eri; Department of Otololaryngology-Head and Neck Surgery, IU School of Medicine
    Stem cell-derived inner ear sensory epithelia are a promising source of tissues for treating patients with hearing loss and dizziness. We recently demonstrated how to generate inner ear sensory epithelia, designated as inner ear organoids, from mouse embryonic stem cells (ESCs) in a self-organizing 3D culture. Here we improve the efficiency of this culture system by elucidating how Wnt signaling activity can drive the induction of otic tissue. We found that a carefully timed treatment with the potent Wnt agonist CHIR99021 promotes induction of otic vesicles-a process that was previously self-organized by unknown mechanisms. The resulting otic-like vesicles have a larger lumen size and contain a greater number of Pax8/Pax2-positive otic progenitor cells than organoids derived without the Wnt agonist. Additionally, these otic-like vesicles give rise to large inner ear organoids with hair cells whose morphological, biochemical and functional properties are indistinguishable from those of vestibular hair cells in the postnatal mouse inner ear. We conclude that Wnt signaling plays a similar role during inner ear organoid formation as it does during inner ear development in the embryo.