Enzymatically Forming Intranuclear Peptide Assemblies for Selectively Killing Human Induced Pluripotent Stem Cells.

Area of Science:

• Biochemistry
• Stem Cell Biology
• Nanotechnology

Background:

• Tumorigenic risk of undifferentiated human induced pluripotent stem cells (iPSCs) hinders clinical translation.
• Selective elimination of undifferentiated iPSCs is crucial for safe cell-based therapies.

Purpose of the Study:

• To develop a novel method for selectively eliminating undifferentiated iPSCs.
• To investigate the mechanism of peptide assembly formation and cell targeting.

Main Methods:

• Synthesis of an l-phosphopentapeptide with self-assembly properties.
• Enzymatic dephosphorylation by alkaline phosphatase (ALP) overexpressed in iPSCs.
• Characterization of peptide assembly morphology (micelles, nanofibers) using circular dichroism and FTIR.
• Assessment of iPSC viability and normal cell toxicity.

Main Results:

• The phosphopentapeptide forms intranuclear α-helical assemblies in iPSCs upon ALP-catalyzed dephosphorylation, leading to rapid cell death (<2 h).
• Normal cells lacking significant ALP expression are unaffected, demonstrating high selectivity.
• Assembly formation is dependent on ALP activity, phosphotyrosine position, and leucine chirality.

Conclusions:

• Enzymatic noncovalent synthesis enables selective targeting of cell nuclei via intranuclear peptide assemblies.
• This approach provides a novel strategy for eliminating undifferentiated iPSCs, addressing a key barrier to their clinical use.
• The findings may extend to targeting other pathological cells overexpressing specific enzymes.