An Advocacy for the Use of 3D Stem Cell Culture Systems for the Development of Regenerative Medicine: An Emphasis on Photoreceptor Generation

Abstract

IntroductionThe possibility to grow in vitro a specific cell population brings a broad potential to study the biological characteristics of the cell of interest. A culture system allows to dissect the intrinsic processes controlling different cell functions and to investigate cell interactions. This knowledge will serve as a standard to study pathophysiological mechanisms as well as to evaluate the potential of the cells of interest to become a tool for regenerative medicine, for tissue repair using cell transplantation or cell mobilization in situ for cell replacement. Successes were achieved for epithelial cells of the skin [1] or the cornea [2], but innovative protocols have to be established for many organs with a complex structure.The large diversity of the cell populations composing the central nervous system brings a new challenge to the generation of specific neuronal phenotypes. Several groups have attempted and continue to strive to generate fully differentiated neurons in a culture dish such as dopaminergic neurons, motoneurons, serotoninergic neurons and photoreceptors for instance. In this review, we will focus on the advances made in neuroscience that have favored the strategic development of new technologies to drive the generation of specific CNS neuron phenotypes and on photoreceptor production from stem cells.One gold standard, to categorize a cell identity or to evaluate the efficacy of cell commitment from stem cells, is the transplantation challenge to determine whether the isolated cell phenotype can integrate its population in vivo and participate to a physiological function, the pioneer field using this approach being immunology [3]. Concerning the CNS, homotopic transplantation of neural cells attested that certain cell populations can integrate into their original brain region in a host AbstractThe availability of stem cells is of great promise to study early developmental stages and to generate adequate cells for cell transfer therapies. Although many researchers using stem cells were successful in dissecting intrinsic and extrinsic mechanisms and in generating specific cell phenotypes, few of the stem cells or the differentiated cells show the capacity to repair a tissue. Advances in cell and stem cell cultivation during the last years made tremendous progress in the generation of bona fide differentiated cells able to integrate into a tissue after transplantation, opening new perspectives for developmental biology studies and for regenerative medicine. In this review, we focus on the main works attempting to create in vitro conditions mimicking the natural environment of CNS structures such as the neural tube and its development in different brain region areas including the optic cup. The use of protocols growing cells in 3D organoids is a key strategy to produce cells resembling endogenous ones. An emphasis on the generation of retina tissue and photoreceptor cells is provided to highlight the promising developments in this field. Other examples are presented and discussed, such as ...

Stem Cell Transplantation for the Treatment of Cancer: A Review

“…Stem cells have also the potential for use in tissue repair and genesis. 9 Stem cells effectively elicit the hematopoietic stem/progenitor cells (HSPC) and leukemia-initiating cells (LIC) which require CD44 for homing and survival. 10…”