Yanmin Xin, Yiting He, Xingguo Liu
The mitochondrial unfolded protein response (UPRmt) is a conserved mitochondrial stress response that is activated by mitochondrial dysfunction to maintain proteostasis. Although UPRmt has been extensively studied in aging and cancer, its role in trauma and critical illness remains poorly understood. Here, we propose a unifying conceptual framework in which UPRmt functions as a central stress-integration hub that senses and coordinates adaptive responses following acute injury. We systematically review the mechanisms of UPRmt activation triggered by diverse insults and highlight how UPRmt integrates mitochondrial-nuclear communication, and crosstalk with other stress-responses such as the integrated stress response and mitophagy. Beyond cell-autonomous regulation, UPRmt also coordinates systemic adaptation through mitokine-mediated interorgan signaling. Importantly, we emphasize the context-dependent role of UPRmt in trauma and critical illness. Moderate activation promotes mitochondrial recovery, limits reactive oxygen species accumulation, and supports immune cell function, thereby enhancing tissue resilience and repair. In contrast, sustained or dysregulated UPRmt contributes to mitochondrial failure, sterile inflammation, and the progression to systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). Furthermore, we discuss emerging evidence linking UPRmt to immune regulation and inflammatory responses, and propose that targeting key regulatory nodes within this stress-integration network may offer novel therapeutic strategies for a broad spectrum of human diseases. Crucially, we synthesize how UPRmt mechanisms contribute to post-traumatic mitochondrial damage, sterile inflammation, SIRS, and MODS. We propose that targeting key regulatory nodes within this stress-integration network may offer novel therapeutic strategies for trauma, burns, and critical illness.