Protein&Cell

2019 Vol. 10, No. 1

In this issue, Li et al. reported the application of extended pluripotent stem (EPS) cells in generating gene-targeted mouse models, which permits direct and rapid constructing mouse models through tetraploid complementation. In the same issue, Du et al. reported efficient derivation of EPS cells from NOD-scid Il2rg^-/- mice, which are refractory to pluripotent cell establishment. Collectively, these two studies show the great potentials of EPS cells in generating mouse models and establishing pluripotent cells with non-permissive backgrounds, which highlight the possibility of using EPS technology to construct mouse models from refractory strains. The cover image shows that the mouse embryo is surrounded by the core four components of EPS culturing medium (LIF, CHIR 99021, DiM and MiH).

Recollection

“In front of patients, I will always be a pupil.” Dr. Xiaoqian Zhang: the founder of the modern Chinese gastroenterology

Lu Wang, Xudong Liu, Wenli Duan, Shu-yang Zhang

2019, 10(1): 1-4. doi: 10.1007/s13238-018-0561-4

[Abstract](548) [PDF 1680KB](263)

Abstract:

Highlight

Extended pluripotent stem cells facilitate mouse model generation

Guanghai Xiang, Haoyi Wang

2019, 10(1): 5-7. doi: 10.1007/s13238-018-0573-0

[Abstract](629) [PDF 48KB](328)

Abstract:

Review

Release and uptake mechanisms of vesicular Ca²⁺ stores

Junsheng Yang, Zhuangzhuang Zhao, Mingxue Gu, Xinghua Feng, Haoxing Xu

2019, 10(1): 8-19. doi: 10.1007/s13238-018-0523-x

[Abstract](658) [PDF 1490KB](956)

Abstract:
Cells utilize calcium ions (Ca²⁺) to signal almost all aspects of cellular life, ranging from cell proliferation to cell death, in a spatially and temporally regulated manner. A key aspect of this regulation is the compartmentalization of Ca²⁺ in various cytoplasmic organelles that act as intracellular Ca²⁺ stores. Whereas Ca²⁺ release from the large-volume Ca²⁺ stores, such as the endoplasmic reticulum (ER) and Golgi apparatus, are preferred for signal transduction, Ca²⁺ release from the small-volume individual vesicular stores that are dispersed throughout the cell, such as lysosomes, may be more useful in local regulation, such as membrane fusion and individualized vesicular movements. Conceivably, these two types of Ca²⁺ stores may be established, maintained or refilled via distinct mechanisms. ER stores are refilled through sustained Ca²⁺ influx at ER-plasma membrane (PM) membrane contact sites (MCSs). In this review, we discuss the release and refilling mechanisms of intracellular small vesicular Ca²⁺ stores, with a special focus on lysosomes. Recent imaging studies of Ca²⁺ release and organelle MCSs suggest that Ca²⁺ exchange may occur between two types of stores, such that the small stores acquire Ca²⁺ from the large stores via ER-vesicle MCSs. Hence vesicular stores like lysosomes may be viewed as secondary Ca²⁺ stores in the cell.

Short articles

Rapid generation of gene-targeted EPS-derived mouse models through tetraploid complementation

Haibo Li, Chaoran Zhao, Jun Xu, Yaxing Xu, Chunmei Cheng, Yinan Liu, Ting Wang, Yaqin Du, Liangfu Xie, Jingru Zhao, Yanchuang Han, Xiaobao Wang, Yun Bai, Hongkui Deng

2019, 10(1): 20-30. doi: 10.1007/s13238-018-0556-1

[Abstract](746) [PDF 5820KB](735)

Abstract:
One major strategy to generate genetically modified mouse models is gene targeting in mouse embryonic stem (ES) cells, which is used to produce gene-targeted mice for wide applications in biomedicine. However, a major bottleneck in this approach is that the robustness of germline transmission of gene-targeted ES cells can be significantly reduced by their genetic and epigenetic instability after long-term culturing, which impairs the efficiency and robustness of mouse model generation. Recently, we have established a new type of pluripotent cells termed extended pluripotent stem (EPS) cells, which have superior developmental potency and robust germline competence compared to conventional mouse ES cells. In this study, we demonstrate that mouse EPS cells well maintain developmental potency and genetic stability after long-term passage. Based on gene targeting in mouse EPS cells, we established a new approach to directly and rapidly generate gene-targeted mouse models through tetraploid complementation, which could be accomplished in approximately 2 months. Importantly, using this approach, we successfully constructed mouse models in which the human interleukin 3 (IL3) or interleukin 6 (IL6) gene was knocked into its corresponding locus in the mouse genome. Our study demonstrates the feasibility of using mouse EPS cells to rapidly generate mouse models by gene targeting, which have great application potential in biomedical research.

Efficient derivation of extended pluripotent stem cells from NOD-scid Il2rg^-/- mice

Yaqin Du, Ting Wang, Jun Xu, Chaoran Zhao, Haibo Li, Yao Fu, Yaxing Xu, Liangfu Xie, Jingru Zhao, Weifeng Yang, Ming Yin, Jinhua Wen, Hongkui Deng

2019, 10(1): 31-42. doi: 10.1007/s13238-018-0558-z

[Abstract](638) [PDF 5069KB](708)

Abstract:
Recently we have established a new culture condition enabling the derivation of extended pluripotent stem (EPS) cells, which, compared to conventional pluripotent stem cells, possess superior developmental potential and germline competence. However, it remains unclear whether this condition permits derivation of EPS cells from mouse strains that are refractory or non-permissive to pluripotent cell establishment. Here, we show that EPS cells can be robustly generated from non-permissive NOD-scid Il2rg^-/- mice through de novo derivation from blastocysts. Furthermore, these cells can also be efficiently generated by chemical reprogramming from embryonic NOD-scid Il2rg^-/- fibroblasts. NOD-scid Il2rg^-/- EPS cells can be expanded for more than 20 passages with genomic stability and can be genetically modified through gene targeting. Notably, these cells contribute to both embryonic and extraembryonic lineages in vivo. More importantly, they can produce chimeras and integrate into the E13.5 genital ridge. Our study demonstrates the feasibility of generating EPS cells from refractory mouse strains, which could potentially be a general strategy for deriving mouse pluripotent cells. The generation of NOD-scid Il2rg^-/- EPS cell lines permits sophisticated genetic modification in NOD-scid Il2rg^-/- mice, which may greatly advance the optimization of humanized mouse models for biomedical applications.

Research articles

Neoblast-enriched zinc finger protein FIR1 triggers local proliferation during planarian regeneration

Xiao-Shuai Han, Chen Wang, Fang-hao Guo, Shuang Huang, Yong-Wen Qin, Xian-Xian Zhao, Qing Jing

2019, 10(1): 43-59. doi: 10.1007/s13238-018-0512-0

[Abstract](599) [PDF 15204KB](919)

Abstract:
Regeneration, relying mainly on resident adult stem cells, is widespread. However, the mechanism by which stem cells initiate proliferation during this process in vivo is unclear. Using planarian as a model, we screened 46 transcripts showing potential function in the regulation of local stem cell proliferation following 48 h regeneration. By analyzing the regeneration defects and the mitotic activity of animals under administration of RNA interference (RNAi), we identified factor for initiating regeneration 1 (Fir1) required for local proliferation. Our findings reveal that Fir1, enriched in neoblasts, promotes planarian regeneration in any tissue-missing context. Further, we demonstrate that DIS3 like 3'-5' exoribonuclease 2 (Dis3l2) is required for Fir1 phenotype. Besides, RNAi knockdown of Fir1 causes a decrease of neoblast wound response genes following amputation. These findings suggest that Fir1 recognizes regenerative signals and promotes DIS3L2 proteins to trigger neoblast proliferation following amputation and provide a mechanism critical for stem cell response to injury.

Letters

Hepatitis B virus is degraded by autophagosome-lysosome fusion mediated by Rab7 and related components