Characterization of the model for experimental testicular teratoma in 129/SvJ-mice

Bioprinted research models of urological malignancy

Urological malignancy (UM) is among the leading threats to health care worldwide. Recent years have seen much investment in fundamental UM research, including mechanistic investigation, early diagnosis, immunotherapy, and nanomedicine. However, the results are not fully satisfactory. Bioprinted research models (BRMs) with programmed spatial structures and functions can serve as powerful research tools and are likely to disrupt traditional UM research paradigms. Herein, a comprehensive review of BRMs of UM is presented. It begins with a brief introduction and comparison of existing UM research models, emphasizing the advantages of BRMs, such as modeling real tissues and organs. Six kinds of mainstream bioprinting techniques used to fabricate such BRMs are summarized with examples. Thereafter, research advances in the applications of UM BRMs, such as culturing tumor spheroids and organoids, modeling cancer metastasis, mimicking the tumor microenvironment, constructing organ chips for drug screening, and isolating circulating tumor cells, are comprehensively discussed. At the end of this review, current challenges and future development directions of BRMs and UM are highlighted from the perspective of interdisciplinary science.

Neonatal Porcine Germ Cells Dedifferentiate and Display Osteogenic and Pluripotency Properties

Gonocytes are progenitors of spermatogonial stem cells in the neonatal testis. We have previously shown that upon culturing, neonatal porcine gonocytes and their colonies express germ cell and pluripotency markers. The objectives of present study were to investigate in vitro trans-differentiation potential of porcine gonocytes and their colonies into cells from three germinal layers, and to assess pluripotency of cultured gonocytes/colonies in vivo. For osteogenic and tri-lineage differentiation, cells were incubated in regular culture media for 14 and 28 days, respectively. Cells were cultured for an additional 14 days for osteogenic differentiation or 7 days for differentiation into derivates of the three germinal layers. Osteogenic differentiation of cells and colonies was verified by Alizarin Red S staining and tri-lineage differentiation was confirmed using immunofluorescence and gene expression analyses. Furthermore, upon implantation into recipient mice, the cultured cells/colonies developed teratomas expressing markers of all three germinal layers. Successful osteogenic differentiation from porcine germ cells has important implications for bone regeneration and matrix formation studies. Hence, gonocytes emerge as a promising source of adult pluripotent stem cells due to the ability to differentiate into all germinal layers without typical biosafety risks associated with viral vectors or ethical implications.

Biological roles of glial fibrillary acidic protein as a biomarker in cartilage regenerative medicine

Glial fibrillary acidic protein (GFAP) is an intermediate filament that is expressed in specifically expressed auricular chondrocytes, which are good cell sources of cartilage regenerative medicine. Although our group uses GFAP as a biomarker of matrix production in the cultured auricular chondrocytes, the biological roles of GFAP in auricular chondrocytes has remained unknown. In this study, we demonstrated the biological functions of GFAP in the human and mouse derived auricles to clarify the significance and role with the chondrocytes of GFAP in order to provide useful information for reliable and safe regenerative medicine. We examined the cell responses to stretch stress for these chondrocytes and completed a nuclear morphological analysis. Based on these results, GFAP seems to support the resistance to severe mechanical stress in the tissue which physiologically suffers from a stretch overload, and plays pivotal roles in the conservation of cell structures and functions through the maintenance of nuclear morphology.

Characterization of pluripotent stem cells

Characterization of pluripotent stem cells is required for the registration of stem cell lines and allows for an impartial and objective comparison of the results obtained when generating multiple lines. It is therefore crucial to establish specific, fast and reliable protocols to detect the hallmarks of pluripotency. Such protocols should include immunocytochemistry (takes 2 d), identification of the three germ layers in in vitro-derived embryoid bodies by immunocytochemistry (immunodetection takes 3 d) and detection of differentiation markers in in vivo-generated teratomas by immunohistochemistry (differentiation marker detection takes 4 d). Standardization of the immunodetection protocols used ensures minimum variations owing to the source, the animal species, the endogenous fluorescence or the inability to collect large amounts of cells, thereby yielding results as fast as possible without loss of quality. This protocol provides a description of all the immunodetection procedures necessary to characterize mouse and human stem cell lines in different circumstances.

Overexpression of cathepsin K accelerates the resorption cycle and osteoblast differentiation in vitro

Bone resorption is a multistep process including osteoclast attachment, cytoskeletal reorganization, formation of four distinct plasma membrane domains, and matrix demineralization and degradation followed by cell detachment. The present study describes the intracellular mechanisms by which overexpression of cathepsin K in osteoclasts results in enhanced bone resorption. Osteoclasts and bone marrow-derived osteoclast and osteoblast precursors were isolated from mice homozygous (UTU17(+/+)) and negative for the transgene locus. Cells cultured on bovine cortical bone slices were analyzed by fluorescence and confocal laser scanning microscopy, and bone resorption was studied by measurements of biochemical resorption markers, morphometry, and FESEM. Excessive cathepsin K protein and enzyme activity were microscopically observed in various intracellular vesicles and in the resorption lacunae of cathepsin K-overexpressing osteoclasts. The number of cathepsin K-containing vesicles in UTU17(+/+) osteoclasts was highly increased, and co-localization with markers for the biosynthetic and transcytotic pathways was observed throughout the cytoplasm. As a functional consequence of cathepsin K overexpression, biochemical resorption markers were increased in culture media of UTU17(+/+) osteoclasts. Detailed morphometrical analysis of the erosion in bone slices indicated that the increased biosynthesis of cathepsin K was sufficient to accelerate the osteoclastic bone resorption cycle. Cathepsin K overexpression also enhanced osteogenesis and induced the formation of exceptionally small, actively resorbing osteoclasts from their bone marrow precursors in vitro. The present study describes for the first time how enhancement in one phase of the osteoclastic resorption cycle also stimulates its other phases and further demonstrate that tight control and temporal coupling of mesenchymal and hematopoietic bone cells in this multistep process.

Fetal but not adult Leydig cells are susceptible to adenoma formation in response to persistently high hCG level: a study on hCG overexpressing transgenic mice

We have previously demonstrated that male transgenic (TG) mice overexpressing human chorionic gonadotropin (hCG+) develop reproductive organ defects, but no tumors, in adult age. In this study, the effects of persistently elevated hCG were followed in TG males between day 5 postpartum and adulthood. Leydig cell (LC) adenomas were found in prepubertal mice, most prominently at the age of 10 days, but not in adult age. Serum testosterone concentrations were significantly increased in TG males at all ages studied. The phenotype of the prepubertal hCG+ males resembled that found in boys upon expression of constitutively activating luteinizing hormone (LH) receptor mutations. The temporal expression patterns of the fetal LC marker gene, thrombospondin 2, and those of adult LCs, hydroxysteroid dehydrogenase-6, delta5-3-beta and prostaglandin D synthase, were similar in wild-type and hCG+ males. Hence, the postnatal adenomas resemble functionally fetal LCs, and only these cells are susceptible to hCG-induced tumorigenesis. Our findings demonstrate a novel intriguing difference between the fetal and adult LC populations and provide further insight into the potential tumorigenic effects of gonadotropins.

Reproductive disturbances, pituitary lactotrope adenomas, and mammary gland tumors in transgenic female mice producing high levels of human chorionic gonadotropin

To assess the consequences of prolonged exposure to elevated levels of LH/human chorionic gonadotropin (hCG) in the female, we developed a transgenic (TG) mouse model (hCGbeta+) that overexpresses the hCGbeta-subunit cDNA. Because of the promoter used, ubiquitin C, the transgene is expressed in multiple tissues, including the pituitary gland, in which coupling with the endogenous common alpha-subunit results in synthesis of high levels of bioactive hCG. The TG females presented with precocious puberty, infertility, enhanced ovarian steroidogenesis, and abnormal uterine structure. Pituitary enlargement was evident from the age of 2 months, which progressed to adenomas by the age of 10-12 months. Immunohistochemical studies and electron microscopy demonstrated lactotrope origin for the adenomas, associated with severe hyperprolactinemia. The mammary glands of TG females showed marked lobuloalveolar development followed by mammary tumors with characteristics of adenocarcinoma at the age of 9-12 months. More than 90% of penetrance and high frequency of metastasis (47%) was observed. Formation of the pituitary and mammary gland tumors was totally abolished by ovariectomy despite persistently elevated hCG levels. Taken together, these findings suggest that the hCG-induced aberrations of ovarian function are clearly responsible for the extragonadal tumors observed in these TG mice.