Systemic mitochondrial dysfunction is apparent in the pathophysiology of Alzheimer's disease (AD). However, the factors driving bioenergetic decline remain unclear. This study utilized serum samples from older adults with normal cognition, mild cognitive impairment, and dementia to identify circulating molecules that can drive mitochondrial dysfunction in the context of AD. We used mass spectrometry to measure the abundance of lipid metabolites and applied tiered selection criteria to identify candidate "mito-inhibitory" molecules. These criteria were based on correlations with (1) in vitro bioenergetic effects of whole serum samples on naïve cells, (2) the bioenergetic capacity of blood cells from the serum donor, and (3) cognition, as measured by the modified mini-mental state exam. Mito-inhibitory lipid candidates were validated by examining their bioenergetic effects on neurons, myoblasts, and fibroblasts in vitro. Our results indicate that nervonic acid and 15-epi Prostaglandin A1 (15-epi-PGA1) are elevated in participants with dementia compared to those with normal cognition. Importantly, both metabolites inhibited mitochondrial function across multiple cell types in vitro. High resolution respirometric analyses reveal that inhibitory effects from lipid treatment occur via broad inhibition of the electron transfer system (ETS) with no change in overall mitochondrial content. This study provides insights into the mechanisms underlying systemic bioenergetic decline associated with AD dementia. The identification of circulating factors that drive mitochondrial bioenergetic decline may inform the development of mitochondrial therapeutics for AD.
© 2025. The Author(s).

Ferroptosis is an iron-dependent form of cell death that influences cancer immunity. Therapeutic modulation of ferroptosis is considered a potential strategy to enhance the efficacy of other cancer therapies, including immunotherapies such as chimeric antigen receptor (CAR) T-cell therapy. In this study, we demonstrated that IFNκ influenced the induction of ferroptosis. IFNκ could enhance the sensitivity of tumor cells to ferroptosis induced by the small molecule compound erastin and the polyunsaturated fatty acid arachidonic acid. Mechanistically, IFNκ in combination with arachidonic acid induced immunogenic tumor ferroptosis via an IFNAR/STAT1/ACSL4 axis. Moreover, CAR T cells engineered to express IFNκ showed increased antitumor efficiency against H460 cells (antigen positive) and H322 cells (antigen-negative) both in vitro and in vivo. We conclude that IFNκ is a potential cytokine that could be harnessed to enhance the antitumor function of CAR T cells by inducing tumor ferroptosis.
©2024 The Authors; Published by the American Association for Cancer Research.

Tumor cell intrinsic ferroptosis-initiating mechanisms are unknown. Here, we discover that T cell-derived interferon (IFN)γ in combination with arachidonic acid (AA) induces immunogenic tumor ferroptosis, serving as a mode of action for CD8+ T cell (CTL)-mediated tumor killing. Mechanistically, IFNγ stimulates ACSL4 and alters tumor cell lipid pattern, thereby increasing incorporations of AA into C16 and C18 acyl chain-containing phospholipids. Palmitoleic acid and oleic acid, two common C16 and C18 fatty acids in blood, promote ACSL4-dependent tumor ferroptosis induced by IFNγ plus AA. Moreover, tumor ACSL4 deficiency accelerates tumor progression. Low-dose AA enhances tumor ferroptosis and elevates spontaneous and immune checkpoint blockade (ICB)-induced anti-tumor immunity. Clinically, tumor ACSL4 correlates with T cell signatures and improved survival in ICB-treated cancer patients. Thus, IFNγ signaling paired with selective fatty acids is a natural tumor ferroptosis-promoting mechanism and a mode of action of CTLs. Targeting the ACSL4 pathway is a potential anti-cancer approach.
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