A Comparative Analysis of Tissue-Specific Proteomes Revealing Conserved Paracrine Regenerative Mechanisms and Specialized Therapeutic Functions of Precursor Stem Cells Secretomes

Precursor stem cells (PSCs) represent a promising platform for regenerative medicine due to their capacity to secrete bioactivefactors that support tissue repair, immune modulation, and cellular homeostasis. In this study, conditioned supernatants obtainedfrom Retina, Kidney, Brain, Heart, and Thymus progenitor/precursor stem cell cultures were subjected to comprehensive proteomic profiling to characterize their regenerative potential and tissue-specific functional properties. Rabbit PSC samples were cultured in serum-free (SF) medium, washed with phosphate-buffered saline (PBS), and processed for protein extraction. Lysateswere pooled by tissue type where applicable and subjected to three freeze-thaw cycles, vortex mixing, incubation, centrifugation,and protein quantification using the Bradford assay prior to proteomic analysis.Proteomic profiling identified a conserved set of proteins across all PSC cultures, revealing core regenerative networks associated with extracellular matrix remodeling, cellular communication, paracrine signaling, tissue repair, and immunomodulatory activity. These shared molecular pathways confirm that all examined PSC populations possess the fundamental prerequisites for regenerative and immune-regulatory functions commonly attributed to mesenchymal stem cell (MSC)-derived secretome therapies.Despite these common regenerative features, each PSC population exhibited distinct functional phenotypes characterized by tissue-specific proteomic signatures. Differential protein expression patterns indicated specialized biological emphases, includingstructural regeneration, anti-inflammatory and immunomodulatory regeneration, balanced regenerative support, and paracrinemediated tissue repair. These findings demonstrate that while PSC cultures share a universal regenerative framework, their secretomes retain functional characteristics reflective of their tissue of origin.Collectively, the data provide evidence that PSC-derived conditioned media contain both conserved and tissue-specific regenerative factors, supporting their potential application as targeted cell-free therapeutic platforms. The identification of core regenerative networks alongside specialized proteomic profiles advances our understanding of PSC biology and offers a foundation for the development of precision regenerative medicine strategies.