On November 28, 2025, a study "Innate immune and metabolic signals induce mitochondria-dependent membrane lysis via mitoxyperiosis" was published in Cell. The researchers used MCE products such as 1009298-09-2, CZ415, Dactolisib, and CK-666 to discover a new cell death mechanism called "Mitoxyperilysis."

Mitoxyperilysis is induced by the interaction between innate immune signaling and metabolic dysregulation. It features long-term contact between mitochondria and the plasma membrane, causing oxidative damage, membrane rupture, and cell lysis. Notably, it is regulated by the mTOR pathway and independent of caspase activity, different from previously reported cell death processes. To clarify the mechanisms, the researchers explored how innate immune activation and metabolic disruption jointly induce this cytolytic death, and their findings offer valuable insights.

In many pathological conditions, innate immune activation is often accompanied by nutrient deficiencies, causing metabolic disorders. To study the mechanisms, researchers used bone marrow-derived macrophages (BMDMs). They treated BMDMs under carbon starvation (CS) and stimulated them with innate immune signals (PAM3, poly(I:C), LPS, and R848) to simulate "inflammation-induced metabolic dysregulation-associated cell death" (IIAMD) in disease states.

The data showed that BMDMs were resistant to cytolytic death when exposed to CS or innate immune activation alone. But when CS was combined with PAM3, LPS, or R848 (not poly(I:C)), it triggered a strong lytic cell death response, and the release of lactate dehydrogenase (LDH) and high-mobility group box 1 (HMGB1), markers of cell membrane rupture, was observed.

Importantly, this cell death response to IIAMD stimuli was independent of previously reported mechanisms, suggesting a unique inflammatory cell death pathway.

Comprehensive metabolomic analysis characterized metabolic features of Mitoxyperilysis. Cells treated with LPS plus carbon starvation (CS) showed distinct metabolic profile changes compared to normal conditions, CS, or LPS alone, with reduced glutathione (GSH) metabolism in the LPS + CS group.

Live-cell imaging with CellROX DeepRed (CellROX-DR) showed increasing intracellular oxidative stress levels before membrane damage and cell death. Most propidium iodide (PI)-positive (dead) cells also had CellROX-DR, suggesting oxidative stress drives the cell death process.

Advanced confocal live-cell imaging showed that under LPS + CS treatment, CellROX-DR-positive spots (oxidative stress) localized near the plasma membrane for over 20 minutes. At these contact sites, the membrane degenerated and ruptured, allowing Sytox dye to enter and stain the nucleus.

The oxidative stress was shown to originate from the mitochondria. Prolonged contact between mitochondria and the plasma membrane is characteristic of IIAMD-induced cell death. Lipid peroxidation increased before membrane rupture.

The authors call this "mitochondrial periplasmic oxygen transfer," which causes localized oxidative damage at membrane contact sites, leading to membrane rupture and cell lysis, named "mitochondrial periplasmic oxygen transfer-induced cell lysis" (Mitoxyperilysis).

The researchers found mitochondrial damage was crucial in IIAMD-induced cell death. So, they studied BH3 domain proteins involved in mitochondrial destruction.

They created immortalized bone marrow-derived macrophage (iBMDM) knockout cell lines with single, double, or triple-gene defects in Bax, Bak1, and Bid. Notably, Bax^-/- Bak1^-/- Bid^-/- cells were resistant to IIAMD-induced cell death and inflammatory body activation, and their oxidative stress levels were significantly lower than in control cells.

These findings show that BAX, BAK1, and BID are key upstream regulatory factors for IIAMD-triggered mitochondrial damage and oxidative stress-mediated inflammatory cell death. That is, BAX, BAK1, and BID-dependent mitochondrial damage and oxidative stress drive the mitochondrial oxidative death in Mitoxyperilysis.

To uncover mechanisms regulating mitochondrial damage and plasma membrane contact during Mitoxyperilysis, researchers screened 2,050 small molecules, identifying three mTOR kinase inhibitors protecting against LPS and CS-induced cell death. These inhibitors could dose-dependently suppress mitochondrial oxidative damage.

RNA sequencing showed the mTOR pathway was significantly upregulated after LPS+CS treatment. Mitochondrial damage and plasma membrane contact triggers activated mTORC1 and mTORC2.

Data revealed total glutathione levels remained low during mTOR inhibition, and mTOR inhibition couldn't restore impaired mitochondrial respiratory function induced by IIAMD. After mTOR inhibition, LPS + CS-treated cells maintained high oxidative stress and showed prolonged plasma membrane permeability.

These findings suggest mTOR activation and oxidative stress are independent in mitochondrial oxidative damage. mTOR promotes cell death following mitochondrial dysfunction during Mitoxyperilysis.

To uncover the mechanism of mTOR regulating this contact, researchers did live-cell imaging studies. When mTOR was active in cells treated with IAMD, mitochondria-membrane contact duration was extended. IIAMD reduced cell membrane mechanics and pseudopodia formation.

In contrast, when cells were treated with mTOR inhibitor Torin-1, lamellipodia frequently formed, as confirmed by electron microscopy. Lamellipodia often form near mitochondria-membrane contact sites, disrupting the association between membrane-bound mitochondria and the plasma membrane and shortening their contact duration.

Further investigation showed that RhoA and other Rho-GTPases, which control actin polymerization, regulate lamellipodia motility and cell membrane dynamic changes. After LPS + CS treatment, RhoA activity decreased, but Torin-1 partially restored it.

Microscopic imaging revealed that in LPS + CS-treated cells, mitochondria were peripherally distributed with little F-actin. In contrast, Torin-1 treatment induced F-actin-rich lamellipodia that encapsulated protruding mitochondria.

Based on discoveries about the Mitoxyperilysis pathway, researchers explored its cancer therapeutic potential. In a B16 melanoma xenograft model, they intratumorally administered low-dose LPS with fasting treatment to tumor-bearing mice. Remarkably, there was a significant reduction in tumor volume and a large increase in tumor necrosis.

Interestingly, when mice were pre-treated with mTOR inhibitor Torin-1 before fasting and injections, tumor size didn't change much, but tumor necrosis decreased. Further analysis showed RhoA activity in tumors was significantly reduced, but partially restored after Torin-1 treatment. In necrotic tumors, damaged mitochondria-like organelles near the plasma membrane were observed, supporting the key role of mitochondrial membrane-associated damage in tumor cell death in vivo. These data suggest activating mitochondrial damage can reduce tumor burden.