Mustafa, D. | Search bioRxiv

bioRxiv2025

Amino acid restriction sensitizes lung cancer cells toferroptosis via GCN2-dependent activation of the integratedstress response

Lung cancer cells are vulnerable to iron-dependent oxidation of phospholipids leading to ferroptosis, a process countered by glutathione peroxidase-4 that converts lipid hydroperoxides to lipid alcohols using glutathione as reducing agent. Since ferroptosis-inducing agents are in clinical development, identifying modifiers of ferroptosis susceptibility is warranted. Here, we investigate the impact of amino acids on susceptibility to buthionine sulfoximine (BSO), a glutamate-cysteine ligase inhibitor that blocks biosynthesis of glutathione. We found that reduced amounts of amino acids other than cysteine increased the sensitivity to BSO and other ferroptosis-inducing agents, in a panel of mouse and human lung cancer cells, without affecting glutathione production. Activation of the amino acid sensor protein GCN2 and the integrated stress response lowered the threshold for lipid peroxidation by stimulating ATF4-dependent mitochondrial respiration. The finding has implications for lung cancer metabolism and raises the possibility of using protein restricted diets in combination with ferroptosis-inducing agents as cancer therapies.

cancer biology↗

bioRxiv2025

Spatial Transcriptomics of Schizophrenia Insular Cortex Reveals Blood-Brain Barrier Hyperglycolysis and Increased Parenchymal Mitochondrial Respiration

IntroductionThe blood-brain barrier (BBB) acts as the metabolic and immunological gatekeeper of the brain. Since alterations in neurometabolism and neuroimmunity are found in schizophrenia-spectrum disorders (SSD) which are hypothesised to be important disease mechanisms, we aimed to investigate whether changes in BBB function could underly these findings using a novel spatially resolved transcriptomics technique. MethodsFormalin-fixed paraffin-embedded insular cortex tissue from 8 brain donors with SSD and 8 matched controls derived from the Netherlands Brain Bank-Psychiatry were selected for whole transcriptome analysis (GeoMx Human Whole Transcriptome Atlas) on the GeoMx Digital Spatial Profiler platform. Combining nuclear staining with an endothelial cell marker (CD31) allowed for the separation of BBB and parenchyma areas of interest (AOIs) for downstream sequencing on the Illumina NextSeq 2000. For each sample, biological triplicates were sequenced. Comparing SSD to control for both the BBB and parenchyma AOIs, differentially expressed genes (DEGs) were identified using a Linear Mixed Model, a heatmap was created displaying all genes with a false-discovery rate <0.01, and Fast Gene Set Enrichment Analysis was used for pathway analysis. ResultsA total of 96 whole transcriptome profiles were generated (24 BBB and 24 parenchyma for both SSD and controls). Expression of endothelial genes (PECAM1/CD31, CLDN5, VWF, CD34, ENG) was significantly increased in BBB, confirming enrichment of endothelial cells (ECs) in this AOI. Cluster analysis showed perfect clustering of BBB versus parenchyma, and good clustering of SSD samples within the BBB cluster. At a |Log2FC| [≥] 0.25, we identify 265 significantly DEGs in the BBB AOI and 6 in the parenchyma AOI comparing SSD to control. Pathway analysis revealed a distinct metabolic transcriptional profile in SSD, characterized by hyperglycolysis in the BBB and increased mitochondrial energy metabolism in parenchyma. ConclusionOur findings implicate the BBB in the metabolic pathophysiology of SSD. Furthermore, our findings add nuance to the existing understanding of brain bioenergetic alterations in SSD, suggesting that metabolic changes may be region-specific rather than generalized. This highlights the need for a brain mapping approach examining multiple brain regions from the same donor. Finally, the distinct metabolic profiles of the BBB and brain parenchyma emphasize the importance of spatial multi-omics in post-mortem psychiatric research and the potential for therapies targeting BBB function in SSD.

neuroscience↗