Mammary Fibroblasts Secrete Damage Associated Molecular Patterns through Extracellular Vesicles in Response to...

Area of Science:

• Radiation oncology
• Cellular biology
• Molecular mechanisms of radiation injury

Background:

• Ionizing radiation (IR) is a cornerstone of cancer treatment, inducing cell death and senescence.
• Tissue injury from IR involves damage-associated molecular patterns (DAMPs) that trigger inflammation.
• The role of extracellular vesicles (EVs) and DAMP release in radiation injury is not fully understood.

Purpose of the Study:

• To investigate the mechanisms of DAMP release and EV secretion following IR.
• To characterize the cargo of EVs secreted by IR-exposed cells.
• To explore the role of specific proteins in IR-induced EV secretion.

Main Methods:

• Inducing acute IR damage in mammary fibroblasts.
• Analyzing cellular phenotype and EV secretion rates.
• Performing quantitative proteomic analysis on EVs.
• Utilizing genetic knockdown of the GTPase Rab27a.

Main Results:

• Acute IR induced a senescence-like phenotype and increased EV secretion in mammary fibroblasts.
• IR-induced EVs were enriched with DAMPs and pro-inflammatory mediators.
• Knockdown of Rab27a reduced IR-induced EV secretion and DAMP enrichment in EVs.

Conclusions:

• EVs play a significant role in mediating inflammatory responses post-IR.
• EV-associated proteins are critical mediators of the cellular response to radiation injury.
• Rab27a is essential for IR-induced EV secretion and DAMP loading.