Multiple indirect targets via secreted cytokines and growth factors

Multiple indirect targets via secreted cytokines and growth factors is a pharmacological classification used to describe the mechanism of action for complex biological therapeutics, particularly cell-based therapies like mesenchymal stem cells (MSCs). Rather than interacting with a single, well-defined molecular target such as a specific receptor or enzyme, these therapies exert their effects by releasing a diverse array of signaling molecules into the local environment (Galipeau & Sensébé, 2018). These secreted factors, collectively known as the secretome, include various cytokines, chemokines, and growth factors that subsequently bind to multiple receptors on target cells to modulate immune responses, promote tissue repair, or inhibit apoptosis (Pittenger et al., 2019). This indirect approach is characteristic of regenerative medicine and advanced immunotherapies where the goal is to orchestrate a broad physiological shift rather than blocking a single pathway (Kapur & Smith, 2021). Consequently, the target is not a single entity but a network of downstream signaling events triggered by the primary therapeutic agent. This classification is often used in drug databases like ChEMBL to account for the pleiotropic effects of living drugs or multi-component biologics that lack a singular primary target (ChEMBL, 2024). Clinical applications of this mechanism include the treatment of graft-versus-host disease and chronic inflammatory conditions where multi-pathway modulation is beneficial. However, this complexity also presents significant challenges in drug standardization and the prediction of systemic safety profiles.

Other names

Secretome-mediated signalingParacrine signaling mechanismIndirect cytokine modulationBystander effectNon-specific indirect targets

Paracrine and autocrine signaling via the secretion of a complex secretome (cytokines, growth factors, and extracellular vesicles) that modulates the tissue microenvironment.