Biology subjects

Landowski, M.

Publications and source records attributed to Landowski, M..

4 recordsLinked to original sources

bioRxiv2026

DHA deficiency drives neural oxidized-lipid stress and microglial activation

Despite the well-established importance of DHA in neural health, the mechanisms by which neural tissues respond to declining DHA availability and how this response contributes to aging remain poorly understood. Here, we show that chronic DHA deficiency triggers a neural-specific compensatory lipid-remodeling program with pathological consequences. DHA loss causes a neural-tissue-selective shift from DHA-containing phospholipids toward arachidonic and adrenic acid-containing omega-6 species, accompanied by an RPE-associated polyunsaturated fatty acid biosynthetic program. This remodeling expands the pool of oxidation-prone lipids, redirects lipid peroxidation toward omega-6-derived products, and increases oxidative damage. Dietary DHA restoration reversed lipid remodeling, oxidative stress, inflammation, and visual dysfunction, establishing DHA deficiency as a causal driver of these phenotypes in mice. We identified an APOE-dependent oxidized-lipid disposal pathway that transfers oxidized lipid cargo from the neural retina to subretinal microglia, limiting its retention within the neural retina and protecting against degeneration. However, with persistent lipid uptake, oxidized phospholipids accumulate in microglial lysosomes, with sustained galectin-3 activation. Galectin-3 deficiency preferentially protected against later-stage degeneration, indicating that prolonged lipid burden converts the initial clearance response into a pathogenic response. Physiologically aged retinas also showed a similar shift toward omega-6 lipid accumulation. These findings define an adaptive-to-maladaptive lipid-remodeling-microglia axis linking declining DHA availability to age-related neural dysfunction.

physiology↗

bioRxiv2026

TMEM135 deficiency remodels hepatic lipid homeostasis and protein malonylation through a DHA-sensitive lipogenic program buffered by peroxisomal metabolism

TMEM135 has been implicated in lipid metabolism, but its role in regulating hepatic lipid homeostasis remains unclear. Here, we investigated how TMEM135 affects hepatic lipid metabolism using Tmem135 mutant mice with liver-specific Pex5 deletion. The Tmem135 mutation induced a lipogenic state characterized by depletion of docosahexaenoic acid (DHA), activation of SREBP-dependent pathways, and increased monounsaturated fatty acids without causing hepatic steatosis. In contrast, loss of PEX5-dependent peroxisomal function in Tmem135 mutant mice resulted in marked hepatic lipid accumulation, indicating that peroxisomal metabolism buffers the elevated lipogenic state. Fish oil supplementation to Tmem135 mutant mice restored DHA levels and suppressed lipogenesis. Proteomics identified distinct DHA-sensitive metabolic programs, including activation of SREBP-dependent lipogenesis. Quantitative malonyl-proteomics revealed increased malonylation of glycolytic enzymes, accompanied by altered glycolytic output. Together, these findings identify TMEM135 as a central regulator of hepatic lipid metabolism and uncover a coordinated mechanism linking lipid availability, lipogenesis, and post-translational metabolic regulation. HighlightTmem135 mutation induces a lipogenic state with increased lipolysis without hepatic steatosis. PEX5-dependent peroxisomal function buffers lipid accumulation in Tmem135 mutant liver. Fish oil supplementation restores DHA and suppresses SREBP-dependent lipogenesis in Tmem135 mutants. DHA-sensitive protein malonylation targets glycolytic enzymes in Tmem135 mutant liver.

cell biology↗

bioRxiv2025

Mitochondrial fusion controls the development of specialized mitochondrial structure and metabolism in rod photoreceptor cells

Mitochondria are dynamic organelles that undergo continuous morphological changes, yet exhibit unique, cell-type-specific structures. In rod photoreceptor cells of the retina, these structures include elongated mitochondria in the inner segments and a distinct, large, circular mitochondrion in each presynaptic terminal. The mechanisms underlying the establishment and maintenance of these specialized mitochondrial morphologies, along with their functional significance, are not well understood. Here, we investigate the roles of mitochondrial fusion proteins mitofusin 1 (MFN1) and mitofusin 2 (MFN2) in shaping these structures and maintaining photoreceptor cell health. Rod photoreceptor cell-specific ablation of MFN1 and MFN2 resulted in mitochondrial fragmentation by one month of age, suggesting that mitochondrial fusion is essential for the development of photoreceptor cell-specific mitochondrial structures. Notably, the layer structures of the retina examined by light microscopy appeared unaffected at this age. Following this time period, significant photoreceptor cell degeneration occurred by three months of age. Furthermore, we showed that impaired mitochondrial fusion perturbed the balance of proteins involved in glycolysis, oxidative phosphorylation (OXPHOS), and {beta}-oxidation, highlighting the critical role of mitochondrial fusion in ensuring the proper levels of proteins necessary for optimal energy metabolism. Additionally, we identified upregulation of cellular stress pathways such as endoplasmic reticulum (ER) stress and unfolded protein response (UPR), which arise in response to energy deprivation, and cytoprotective biosynthetic pathways mediated by CCAAT/enhancer-binding protein gamma (C/EBP{gamma}) and mammalian target of rapamycin complex 1 (mTORC1) signaling. In summary, our findings indicate that mitochondrial fusion through MFN1 and MFN2 is vital for the development of unique mitochondrial structures and proper energy production, underscoring the fundamental importance of mitochondrial dynamics in photoreceptor cell function and survival. Significance StatementsRod photoreceptor cells exhibit unique mitochondrial morphologies and high energy requirements. In this report, we examined how these unique mitochondrial structures are established and their biological significance. We identified that mitochondrial fusion is essential for the development of characteristic mitochondrial morphologies in rod photoreceptor cells. Furthermore, we demonstrated that impaired mitochondrial fusion disrupts the equilibrium of proteins associated with OXPHOS, glycolysis, and {beta}-oxidation, ultimately leading to an imbalance in cellular energy homeostasis. Our findings also revealed activation of cellular stress pathways, including ER stress and the UPR, which are likely triggered by energy depletion. Additionally, we identified activation of cytoprotective biosynthetic pathways that are engaged to preserve cellular homeostasis and function.

molecular biology↗

bioRxiv2018

Experimental study of Young modulus of Attacus atlas, Vespa crabro, and Libellula depressa wings

This paper describes a scientific research aimed at obtaining data for determining Young modulus of the wings of selected insects species. A small testing machine intended for three-point bending and equipped with instruments registering low forces was constructed for the needs of the experiment. The machine was used to perform numerous bending tests of wings of three species of insects (obtained from a breeding farm): Attacus atlas, Vespa crabro, Libellula depressa in various air-humidity conditions. Values of the force and displacement obtained in the course of the tests were used to calculate Young modulus. In order to do so, it was also necessary to obtain the moment of inertia of the wing cross-section. These values were measured on the basis of the images obtained with a SEM microscope. Obtained results were averaged and presented with a breakdown by air-humidity conditions. It was observed that Young modulus decreased with an increase of humidity; hence the calculations of the percentage decrease of this mechanical parameter were performed. Obtained results were compared with the observed structure which was also presented under light microscope. It transpired that the construction of a wing does not only influence the mechanical values but also it influences their susceptibility to the changes occurring in the environment. Thereby, differences between Lepidoptera and Hymenoptera insects were indicated also within the aspect discussed in this paper.

bioengineering↗