Specially Appointed Researcher Chiba University Chiba, Chiba, Japan
Abstract: Aging leads to tissue dysfunction and death, driven by cellular degeneration. Rejuvenation strategies using reprogramming factors like OCT4, SOX2, KLF4, and c-MYC (OSKM) can reset aging hallmarks by generating induced pluripotent stem cells (iPSC). Later, the transient expression of OSKM was reported to reset some aging hallmarks, extend the life span, restore youthful DNA methylation patterns, and reverse vision loss in mice. However, uncontrolled OSKM expression poses risks of unintended iPSC induction and loss of original cellular identity. To address this, here we developed a novel alternative cellular reprogramming method using c-MYC, BMI1, and Bcl-xL (MBX) to revert iPS-derived lineage-committed cells to their progenitor state, termed “progenitor reprogramming,” without generating iPSCs. Mesenchymal stem cells (MSCs) lose their proliferative and differentiation potential with age, reducing the expression of stemness markers like CD90. During long-term cultures of iPSC-derived MSCs (iPS-MSCs), we observed declining proliferation potential accompanied by gradual loss of cell surface expression of CD90. We confirmed MB or MBX (MB(X)) overexpression (O/E) reversed these trends by reprogramming CD90- differentiated cells back to CD90+ MSCs and enhancing stable proliferation for several months. In contrast, either the continuous or transient OSK O/E impaired cell growth and produced unknown lineage cells and iPSC-like cells. Furthermore, transcriptomics revealed that compared to control and OSK groups, MB-induced progenitor reprogramming upregulated the expression of cell cycle-related genes and pathways while decreasing markers of cellular senescence and factors associated with senescence-associated secretory phenotype (SASP). Finally, we confirmed progenitor reprogramming in iPSC-derived megakaryocytes, myeloid cells, vascular endothelial cells, and vascular smooth muscle cells. In summary, MB(X) represents a distinct set of cellular reprogramming factors that restore differentiated cells to their progenitor state without the risk of unintended cell generation. Thus, MB(X)-driven reprogramming holds significant potential for developing innovative therapeutic strategies with promising applications in regenerative medicine, disease modeling, and drug discovery.
Funding Source: Japan Agency for Medical Research and Development under (JP23bm0404072), Tokyo Biochemical Research Foundation, the JSPS KAKENHI (23K18284), and the JST Fusion Oriented Research for Disruptive Science and Technology (JPMJFR234Q)
