Replacing reprogramming factors with antibodies selected from combinatorial antibody libraries

Nat Biotechnol. 2017 Oct;35(10):960-968. doi: 10.1038/nbt.3963. Epub 2017 Sep 11.

Abstract

The reprogramming of differentiated cells into induced pluripotent stem cells (iPSCs) is usually achieved by exogenous induction of transcription by factors acting in the nucleus. In contrast, during development, signaling pathways initiated at the membrane induce differentiation. The central idea of this study is to identify antibodies that can catalyze cellular de-differentiation and nuclear reprogramming by acting at the cell surface. We screen a lentiviral library encoding ∼100 million secreted and membrane-bound single-chain antibodies and identify antibodies that can replace either Sox2 and Myc (c-Myc) or Oct4 during reprogramming of mouse embryonic fibroblasts into iPSCs. We show that one Sox2-replacing antibody antagonizes the membrane-associated protein Basp1, thereby de-repressing nuclear factors WT1, Esrrb and Lin28a (Lin28) independent of Sox2. By manipulating this pathway, we identify three methods to generate iPSCs. Our results establish unbiased selection from autocrine combinatorial antibody libraries as a robust method to discover new biologics and uncover membrane-to-nucleus signaling pathways that regulate pluripotency and cell fate.

MeSH terms

  • Animals
  • Antibodies / metabolism*
  • Autocrine Communication
  • Blastocyst / cytology
  • Calmodulin-Binding Proteins / metabolism
  • Cellular Reprogramming* / drug effects
  • Clone Cells
  • Combinatorial Chemistry Techniques*
  • Cytoskeletal Proteins / metabolism
  • Fibroblasts / cytology
  • Fibroblasts / drug effects
  • Induced Pluripotent Stem Cells / cytology
  • Induced Pluripotent Stem Cells / drug effects
  • Mice, Inbred C57BL
  • Nerve Tissue Proteins / metabolism
  • Phosphorylation / drug effects
  • Protein Binding / drug effects
  • Proto-Oncogene Proteins c-myc / metabolism
  • Reproducibility of Results
  • SOXB1 Transcription Factors / metabolism
  • Smad Proteins / metabolism
  • Transforming Growth Factor beta / pharmacology
  • Up-Regulation / drug effects

Substances

  • Antibodies
  • Basp1 protein, mouse
  • Calmodulin-Binding Proteins
  • Cytoskeletal Proteins
  • Nerve Tissue Proteins
  • Proto-Oncogene Proteins c-myc
  • SOXB1 Transcription Factors
  • Smad Proteins
  • Transforming Growth Factor beta