Niche Laminin and IGF-1 Additively Coordinate the Maintenance of Oct-4 Through CD49f/IGF-1R-Hif-2α Feedforward Loop in Mouse Germline Stem Cells

Heng-Kien Au; Syue-Wei Peng; Chin-Lin Guo; Chien-Chia Lin; Yi-Lin Wang; Yung-Che Kuo; Tsz-Yau Law; Hong-Nerng Ho; Thai-Yen Ling; Yen-Hua Huang

doi:10.3389/fcell.2021.646644

Niche Laminin and IGF-1 Additively Coordinate the Maintenance of Oct-4 Through CD49f/IGF-1R-Hif-2α Feedforward Loop in Mouse Germline Stem Cells

Front Cell Dev Biol. 2021 Jul 26:9:646644. doi: 10.3389/fcell.2021.646644. eCollection 2021.

Authors

Heng-Kien Au^{1

2

3

4

5}, Syue-Wei Peng^{6

7}, Chin-Lin Guo⁸, Chien-Chia Lin^{6

7}, Yi-Lin Wang^{6

7}, Yung-Che Kuo^{1

6}, Tsz-Yau Law^{6

7}, Hong-Nerng Ho^{1

2

9}, Thai-Yen Ling¹⁰, Yen-Hua Huang^{1

4

5

6

7

11

12}

Affiliations

¹ Taipei Medical University (TMU) Research Center of Cell Therapy and Regeneration Medicine, Taipei Medical University, Taipei, Taiwan.
² Department of Obstetrics and Gynecology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
³ Department of Obstetrics and Gynecology, Taipei Medical University Hospital, Taipei, Taiwan.
⁴ Center for Reproductive Medicine, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan.
⁵ International Ph.D. Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
⁶ Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
⁷ Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
⁸ Institute of Physics, Academia Sinica, Taipei, Taiwan.
⁹ Department of Obstetrics and Gynecology, Taipei Municipal Wanfang Hospital, Taipei, Taiwan.
¹⁰ Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
¹¹ Comprehensive Cancer Center of Taipei Medical University, Taipei, Taiwan.
¹² The Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.

Abstract

The mechanism on how extracellular matrix (ECM) cooperates with niche growth factors and oxygen tension to regulate the self-renewal of embryonic germline stem cells (GSCs) still remains unclear. Lacking of an appropriate in vitro cell model dramatically hinders the progress. Herein, using a serum-free culture system, we demonstrated that ECM laminin cooperated with hypoxia and insulin-like growth factor 1 receptor (IGF-1R) to additively maintain AP activity and Oct-4 expression of AP⁺GSCs. We found the laminin receptor CD49f expression in d2 testicular GSCs that were surrounded by laminin. Laminin and hypoxia significantly increased the GSC stemness-related genes, including Hif-2α, Oct-4, IGF-1R, and CD49f. Cotreatment of IGF-1 and laminin additively increased the expression of IGF-IR, CD49f, Hif-2α, and Oct-4. Conversely, silencing IGF-1R and/or CD49f decreased the expression of Hif-2α and Oct-4. The underlying mechanism involved CD49f/IGF1R-(PI3K/AKT)-Hif-2α signaling loop, which in turn maintains Oct-4 expression, symmetric self-renewal, and cell migration. These findings reveal the additive niche laminin/IGF-IR network during early GSC development.

Keywords: IGF; extracellular matrix; germline stem cell; hypoxia; laminin; niche; self-renewal.