From:  The autophagy-exosome axis in chronic prostatitis/chronic pelvic pain syndrome: a hypothesis-driven narrative review

 Key aspects of exosome biogenesis, cargo, and their link to autophagy in CP/CPPS.

AspectKey components/MarkersFunction/SignificanceLink to autophagy in CP/CPPS
Biogenesis pathwayESCRT complexes (ESCRT-0, -I, -II, -III), ALIX, TSG101Mediates inward budding of the endosomal membrane to form ILVs inside MVBs.Autophagosomes can fuse with MVBs to form amphisomes, directly influencing exosome secretion and cargo [15, 41, 44].
Key surface markersTetraspanins (CD63, CD81, CD9), HSP70, MHC classesUsed for exosome identification and isolation. Indicate endosomal origin, and can influence cellular uptake.General principle: Cellular stress and altered autophagic flux can remodel the exosome surface proteome, potentially affecting biodistribution [10, 44, 45, 102]. CP/CPPS evidence: This specific link remains unexplored in prostate-derived exosomes.
Pro-inflammatory cargoIL-1β, IL-18, TNF-α, HMGB1 (DAMP)Drives inflammation and immune cell activation. Central to CP/CPPS pathology.Impaired autophagy leads to the accumulation of these molecules inside the cell, increasing their loading into exosomes [6, 56, 103].
Immunomodulatory miRNAsmiR-155, miR-21, miR-146aKey regulators of immune responses (e.g., miR-155 promotes M1 macrophage polarization).Autophagy regulates miRNA levels. Dysfunctional autophagy alters the miRNA profile of exosomes, shifting the immune response toward pro-inflammation [104106].
Pain and neural cargoNGF, BDNF, cytokinesMediates neuronal sensitization, contributing to chronic pelvic pain.General principle: Exosomes from stressed cells (e.g., glial, cancer) carry pain mediators that directly sensitize sensory neurons, establishing a role in chronic pain [107, 108]. Specific link to autophagy: The hypothesis that autophagy deficiency in prostate cells enhances this exosomal pain signaling remains to be tested in CP/CPPS models.
Pro-fibrotic cargoTGF-β1, fibronectin, collagenPromotes differentiation of fibroblasts into myofibroblasts, leading to tissue fibrosis.Autophagy is frequently induced by and required for TGF-β1 profibrotic signaling [109111]. Inhibition of autophagy (e.g., ATG5/7 loss) attenuates TGF-β1-driven collagen/fibronectin production [109, 112]. The potential enhancement of exosomal TGF-β1 release under autophagy impairment remains less established.

ATG: autophagy-related; BDNF: brain-derived neurotrophic factor; CP/CPPS: chronic prostatitis/chronic pelvic pain syndrome; DAMP: damage-associated molecular pattern; ESCRT: endosomal sorting complex required for transport; ILVs: intraluminal vesicles; MHC: major histocompatibility complex; MVBs: multivesicular bodies; NGF: nerve growth factor; TGF-β1: transforming growth factor beta 1; TNF-α: tumor necrosis factor-alpha.