Dissecting the Heterogeneity of Senescent Cells Through CITE-seq Integration.

Cellular senescence, a state of persistent growth arrest following cell damage, is associated with aging and age-related diseases. Understanding cell heterogeneity within senescent populations is crucial for developing therapies to mitigate senescence-associated pathologies. The protocol described here outlines an integrated approach to exploit the presence of cell surface proteins on subsets of senescent cells to study their heterogeneity at the single-cell level. After identifying senescence-associated surface proteins by mass spectrometry (MS) and then performing cellular indexing of transcriptomes and epitopes sequencing (CITE-seq) single-cell analysis, we were able to identify unique transcriptomic programs associated with specific surface protein markers expressed in some senescent cells but not in others. We illustrate the utility of this approach by investigating the complex heterogeneity of senescent cell populations. However, this methodology can be applied to other biological scenarios where cells with unique transcriptomic profiles can be studied individually, thanks to the presence of specific cell surface proteins that distinguish them from other cells within the same population.