Derivation of Pluripotent Cells from Mouse SSCs Seems to Be Age Dependent.

Hossein Azizi,Hossein Baharvand,Ursula Hinz,Akbar Hajizadeh Moghaddam,Daniel Nanus,Behrouz Asgari,Sabine Conrad,Heike Peterziel,Thomas Skutella

doi:10.1155/2016/8216312

Abstract

Here, we aimed to answer important and fundamental questions in germ cell biology with special focus on the age of the male donor cells and the possibility to generate embryonic stem cell- (ESC-) like cells. While it is believed that spermatogonial stem cells (SSCs) and truly pluripotent ESC-like cells can be isolated from adult mice, it remained unknown if the spontaneous conversion of SSCs to ESC-like cells fails at some age. Similarly, there have been differences in the literature about the duration of cultures during which ESC-like cells may appear. We demonstrate the possibility to derive ESC-like cells from SSC cultures until they reach adolescence or up to 7 weeks of age, but we point out the impossibility to derive these cells from older, mature adult mice. The inability of real adult SSCs to shift to a pluripotent state coincides with a decline in expression of the core pluripotency genes Oct4, Nanog, and Sox2 in SSCs with age. At the same time genes of the spermatogonial differentiation pathway increase. The generated ESC-like cells were similar to ESCs and express pluripotency markers. In vitro they differentiate into all three germ lineages; they form complex teratomas after transplantation in SCID mice and produce chimeric mice.

Highlights

Pluripotent stem cells (PSCs) are undifferentiated cells which have the potential for proliferation, self-renewal, and differentiation into ectodermal, mesodermal, and endodermal cells of all three embryonic germ layers in vitro and in vivo [1]
While it is believed that spermatogonial stem cells (SSCs) and truly pluripotent embryonic stem cell- (ESC-)like cells can be isolated from adult mice, it remained unknown if the spontaneous conversion of SSCs to ESC-like cells fails at some age
SSCs are the only source of naturally occurring truly pluripotent stem cells in the organism after birth, which do not have to be artificially reprogrammed such as induced pluripotent stem cells (iPSCs)

Summary

Introduction

Pluripotent stem cells (PSCs) are undifferentiated cells which have the potential for proliferation, self-renewal, and differentiation into ectodermal, mesodermal, and endodermal cells of all three embryonic germ layers in vitro and in vivo [1]. Several different approaches were used for the generation of PSCs, including ESCs obtained after fertilization from the inner cell mass of an embryo at the blastocyst stage [1, 2] They were procured by enforced expression of pluripotency genes in somatic cells, giving rise to the so-called induced pluripotent stem cells (iPSCs) [3, 4]; one of the promising methods for a more natural and ethical unproblematic establishment of PSCs is SSCs, especially for therapeutic approaches in human medicine [5,6,7,8,9,10,11]. They are unipotent stem cells under the environmental control of their stem cell niche, under specific culture conditions outside the niche and without any exogenous pluripotency genes, they are able to convert to ESC-like cells at different times after the initiation of culture or isolation of SSCs [5, 9, 10].

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