New tools for cell reprogramming and conversion: Possible applications to livestock

Use of Epigenetic Cues and Mechanical Stimuli to Generate Blastocyst-Like Structures from Mammalian Skin Dermal Fibroblasts

Mammalian embryogenesis is characterized by complex interactions between embryonic and extra-embryonic tissues that coordinate morphogenesis, coupling bio-mechanical and bio-chemical cues, to regulate gene expression and influence cell fate. Deciphering such mechanisms is essential to understand early embryogenesis, as well as to harness differentiation disorders. Currently, several early developmental events remain unclear, mainly due to ethical and technical limitations related to the use of natural embryos.Here, we describe a three-step approach to generate 3D spherical structures, arbitrarily defined "epiBlastoids," whose phenotype is remarkably similar to natural embryos. In the first step, adult dermal fibroblasts are converted into trophoblast-like cells, combining the use of 5-azacytidine, to erase the original cell phenotype, with an ad hoc induction protocol, to drive erased cells into the trophoblast lineage. In the second step, once again epigenetic erasing is applied, in combination with mechanosensing-related cues, to generate inner cell mass (ICM)-like spheroids. More specifically, erased cells are encapsulated in micro-bioreactors to promote 3D cell rearrangement and boost pluripotency. In the third step, chemically induced trophoblast-like cells and ICM-like spheroids are co-cultured in the same micro-bioreactors. The newly generated embryoids are then transferred to microwells, to encourage further differentiation and favor epiBlastoid formation. The procedure here described is a novel strategy for in vitro generation of 3D spherical structures, phenotypically similar to natural embryos. The use of easily accessible dermal fibroblasts and the lack of retroviral gene transfection make this protocol a promising strategy to study early embryogenesis as well as embryo disorders.

Combination of epigenetic erasing and mechanical cues to generate human epiBlastoids from adult dermal fibroblasts

PURPOSE

This study is to develop a new protocol that combines the use of epigenetic cues and mechanical stimuli to assemble 3D spherical structures, arbitrarily defined "epiBlastoids," whose phenotype is remarkably similar to natural embryos.

METHODS

A 3-step approach is used to generate epiBlastoids. In the first step, adult dermal fibroblasts are converted into trophoblast (TR)-like cells, combining the use of 5-azacytidine, to erase the original phenotype, with an ad hoc induction protocol, to drive cells towards TR lineage. In the second step, epigenetic erasing is applied once again, in combination with mechanosensing-related cues, to generate inner cell mass (ICM)-like organoids. Specifically, erased cells are encapsulated into micro-bioreactors to promote 3D cell rearrangement and boost pluripotency. In the third step, TR-like cells are co-cultured with ICM-like spheroids in the same micro-bioreactors. Subsequently, the newly generated embryoids are transferred to microwells to favor epiBlastoid formation.

RESULTS

Adult dermal fibroblasts are successfully readdressed towards TR lineage. Cells subjected to epigenetic erasing and encapsulated into micro-bioreactors rearrange in 3D ICM-like structures. Co-culture of TR-like cells and ICM-like spheroids into micro-bioreactors and microwells induces the formation of single structures with uniform shape reminiscent in vivo embryos. CDX2+ cells localized in the out layer of the spheroids, while OCT4+ cells in the inner of the structures. TROP2+ cells display YAP nuclear accumulation and actively transcribed for mature TR markers, while TROP2- cells showed YAP cytoplasmic compartmentalization and expressed pluripotency-related genes.

CONCLUSION

We describe the generation of epiBlastoids that may find useful application in the assisted reproduction field.

Induced pluripotent stem cells (iPSCs) as game-changing tools in the treatment of neurodegenerative disease: Mirage or reality?

Based on investigations, there exist tight correlations between neurodegenerative diseases' incidence and progression and aberrant protein aggregreferates in nervous tissue. However, the pathology of these diseases is not well known, leading to an inability to find an appropriate therapeutic approach to delay occurrence or slow many neurodegenerative diseases' development. The accessibility of induced pluripotent stem cells (iPSCs) in mimicking the phenotypes of various late-onset neurodegenerative diseases presents a novel strategy for in vitro disease modeling. The iPSCs provide a valuable and well-identified resource to clarify neurodegenerative disease mechanisms, as well as prepare a promising human stem cell platform for drug screening. Undoubtedly, neurodegenerative disease modeling using iPSCs has established innovative opportunities for both mechanistic types of research and recognition of novel disease treatments. Most important, the iPSCs have been considered as a novel autologous cell origin for cell-based therapy of neurodegenerative diseases following differentiation to varied types of neural lineage cells (e.g. GABAergic neurons, dopamine neurons, cortical neurons, and motor neurons). In this review, we summarize iPSC-based disease modeling in neurodegenerative diseases including Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and Huntington's disease. Moreover, we discuss the efficacy of cell-replacement therapies for neurodegenerative disease.