7-Ketocholesterol in disease and aging

Mult-omics analysis reveals the lipid-lowering effects of sea buckthorn and milk thistle solid beverage in hyperlipidemic rats

BACKGROUND

Hyperlipidemia is a common metabolic disorder and a risk factor for cardiovascular disease. The traditional medicine herb, Hippophae rhamnoides L., known as sea buckthorn, has anti-obesity and lipid-lowering effects, while Silybum marianum (L.) Gaertn, known as milk thistle, has hepatoprotective properties and exhibits antioxidant effects.

PURPOSE

To evaluate the effect of sea buckthorn and milk thistle solid beverage (H-S solid beverage) in alleviating hyperlipidemia in rats and explore the underlying mechanisms by analyzing plasma and liver metabolomics, lipidomics, and liver transcriptomics.

METHODS

A hyperlipidemic rat model was established after 2 weeks of high-fat diet (HFD) feeding in Sprague Dawley rats. The administered doses of H-S solid beverage were 0.30 g/kg/d, 0.15 g/kg/d and 0.075 g/kg/d. Serum biochemical parameter detection, histopathological section analysis, untargeted plasma and liver metabolomics, lipidomics, and liver transcriptomics were performed to determine the therapeutic effects of H-S solid beverage and predict the related pathways in rats with hyperlipidemia. Changes in genes and proteins related to lipid metabolism were detected using real-time quantitative polymerase chain reaction and western blotting.

RESULTS

Eighty-nine components were identified in H-S solid beverage using ultra-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry, with flavonoids being the major constituents. The H-S solid beverage significantly reduced body weight, liver index, body fat percentage, lipid accumulation, and liver injury in HFD-fed rats. Fatty acids (FA), bile acid, phosphatidyl ethanolamine, phosphatidylcholine, triglyceride, cholesterol ester, diglyceride and phosphatidylinositol levels were significantly altered in the liver and plasma. Moreover, the transcriptomic analysis suggested that H-S solid beverage significantly altered the hepatic gene expression of cholesterol synthesis (Pdk4, Hmgcs1, and Dhcr24), lipogenesis (Scd, Angptl4, and Angptl8), and FA β-oxidation (Cpt1α, Pparδ, Acsl, Pgc-1α, and Pla2g2d).

CONCLUSION

The solid beverage of sea buckthorn and milk thistle was firstly demonstrated to ameliorate HFD-induced hyperlipidemia. The lipid-lowering and hepatoprotective effects of H-S solid beverage significantly regulated cholesterol synthesis and de novo lipogenesis, as well as FA β-oxidation. In summary, this study highlights the potential of H-S solid beverages for the treatment of hyperlipidemia.

Impact of 7-ketocholesterol on the function and stability of the LAT1 transporter

The L-type amino acid transporter (LAT1, SLC7A5) is involved in supplying essential amino acids for brain and fetal development. The regulation of LAT1 function and stability by cholesterol was previously described in ex vivo and in vitro experimental models. The complexity of the relationship between LAT1 and cholesterol has been further studied by investigating the impact of selected oxidized forms of cholesterol, focusing on the most abundant auto-oxidized form of cholesterol, namely 7-ketocholesterol, which increases with age and pathologies characterized by high reactive oxygen species (ROS) levels. The partial substitution of cholesterol with 7-ketocholesterol in HEK293 cells transiently overexpressing the human LAT1 (HEK293-LAT1), decreases the Vmax of LAT1 mediated transport and the thermal stability of the protein. The impairing effect on transport was directly tested in LAT1 reconstituted proteoliposomes supplemented with 7-ketocholesterol. In this experimental model, it was found that the presence of 7-ketocholesterol altered the transport stimulation by adenosine triphosphate (ATP), as previously described. This was likely due to the higher rigidity of 7-ketocholesterol compared to cholesterol, which alters the membrane/protein interaction, weakening the ATP binding to LAT1. LAT1 transport function was also inhibited when proteoliposomes were supplemented with 7α-hydroxycholesterol or 25-hydroxycholesterol. These deleterious effects may be relevant in chronic pathological conditions characterized by altered cholesterol/oxysterol ratios, ranging from metabolic syndrome to kidney disease and neurological disorders.

Oxysterols, age-related-diseases and nutritherapy: Focus on 7-ketocholesterol and 7β-hydroxycholesterol

Age-related diseases are often associated with a disruption of RedOx balance that can lead to lipid peroxidation with the formation of oxysterols, especially those oxidized on carbon-7: 7-ketocholesterol (also known as 7-oxo-cholesterol) and 7β-hydroxycholesterol. Like cholesterol, these oxysterols have 27 carbons, they are composed of a sterane nucleus and have a hydroxyl function in position 3. The oxysterols 7-ketocholesterol and 7β-hydroxycholesterol are mainly formed by cholesterol autoxidation and are biomarkers of oxidative stress. These two oxysterols are frequently found at increased levels in the biological fluids (plasma, cerebrospinal fluid), tissues and/or organs (arterial wall, retina, brain) of patients with age-related diseases, especially cardiovascular diseases, neurodegenerative diseases (mainly Alzheimer's disease), ocular diseases (cataract, age-related macular degeneration), and sarcopenia. Depending on the cell type considered, 7-ketocholesterol and 7β-hydroxycholesterol induce either caspase- dependent or -independent types of cell death associated with mitochondrial and peroxisomal dysfunctions, autophagy and oxidative stress. The caspase dependent type of cell death associated with oxidative stress and autophagy is defined as oxiapoptophagy. These two oxysterols are also inducers of inflammation. These biological features associated with the toxicity of 7-ketocholesterol, and 7β-hydroxycholesterol are often observed in patients with age-related diseases, suggesting an involvement of these oxysterols in the pathophysiology of these disorders. The cytotoxic effects of 7-ketocholesterol and 7β-hydroxycholesterol are counteracted on different cell models by representative nutrients of the Mediterranean diet: ω3 and ω9 fatty acids, polyphenols, and tocopherols. There are also evidences, mainly in cardiovascular diseases, of the benefits of α-tocopherol and phenolic compounds. These in vitro and in vivo observations on 7-ketocholesterol and 7β-hydroxycholesterol, which are frequently increased in age-related diseases, reinforce the interest of nutritherapeutic treatments to prevent and/or cure age-related diseases currently without effective therapies.

Selective removal of 7-ketocholesterol by a novel atherosclerosis therapeutic candidate reverts foam cells to a macrophage-like phenotype

BACKGROUND AND AIMS

The removal of the toxic oxidized cholesterol, 7-ketocholesterol (7KC), from cells through the administration of therapeutics has the potential to treat atherosclerosis and various other pathologies. While cholesterol is a necessary building block for homeostasis, oxidation of cholesterol can lead to the formation of toxic oxysterols with 7KC being the most prominent. 7KC is primarily formed through the non-enzymatic oxidation of cholesterol and is found in high levels in oxidized LDL (oxLDL) particles, which are highly implicated in heart disease. 7KC is implicated in the pathogenesis of numerous diseases, including multiple sclerosis, hypercholesterolemia, sickle cell anemia, and multiple age-related diseases. Of particular interest is the role of 7KC in the progression of atherosclerosis, with several studies associating elevated 7KC levels with the etiology and severity of the disease and in the underlying transition of macrophages to foam cells.

METHODS

This research aims to elucidate the molecular mechanisms of UDP-003, a novel therapeutic compound, in mitigating the harmful effects of 7KC in mouse and human monocyte and macrophage cell lines.

RESULTS

Experimental evidence demonstrates that administration of UDP-003 can reverse the foam cell phenotype, rejuvenating these cells by returning phagocytic function, preventing loss in efferocytosis ability, and decreasing both reactive oxygen species (ROS) and intracellular lipid droplet accumulation. We further demonstrate that UDP-003 drives urinary excretion of 7KC in vivo and has a safety/toxicity profile compatible with initiation of human clinical trials.

CONCLUSIONS

Our data suggest that the targeted removal of 7KC from foam cells with UDP-003 can potentially prevent and reverse atherosclerotic plaque formation. UDP-003 has the potential to be the first disease-modifying therapeutic approach to treating atherosclerotic disease.

Role of liver X receptor in multiple sclerosis: A long furtive life behind a barrier

Liver X receptors (LXRs) are nuclear receptors that function as transcription factors regulating cholesterol metabolism and are implicated in multiple sclerosis (MS) pathogenesis. This mini-review aims to elucidate the potential role of LXRs in MS neuropathology. MS is the most prevalent inflammatory and demyelinating disease of the central nervous system (CNS), impacting both the brain and spinal cord. Furthermore, alterations in brain cholesterol metabolism in MS can modify the functional activity and immune response of LXRs, which are implicated in MS neuropathology. Dysregulation of LXRs and cholesterol homeostasis is associated with the pathogenesis of MS. LXRs play a critical role in regulating the myelination of nerve sheaths, and defects in LXR function may contribute to the progression of MS. LXRs have immunomodulatory effects, including inhibition of the proliferation of lymphocytes, preventing contact of self-antigens to T cells, and regulating the apoptotic process of T cells. LXRs regulate the activity of microglia, which have pro-inflammatory and anti-inflammatory properties involved in immune regulation and clearance of debris as well as the remyelination process. LXRs regulate the functional activity of glial cells and prevent glial cell-mediated neurodegeneration. LXRs have an important role in the regulation of neuroinflammation during MS neuropathology. LXRs may prevent the progression of neuroinflammation in MS by inhibiting the NF-κB and NLRP3 inflammasome signaling pathways. In conclusion, LXRs play a crucial role in MS neuropathology by mitigating neuroinflammation. These findings proposed that LXR agonists, through modulation of cholesterol homeostasis and inflammatory response, could be effective in the management of MS.

Metal-phenolic networks specifically eliminate hypoxic tumors by instigating oxidative and proteotoxic stresses

Hypoxia, a prevalent characteristic of solid tumors, substantially impairs the efficacy of cancer treatments. However, there are no feasible clinical approaches for treating hypoxic tumors. Here, we develop metal-phenolic networks (CuGI) utilizing the natural glycolysis inhibitor (epigallocatechin gallate) and the essential metal element in the human body (copper ions), specifically targeting and annihilating hypoxic cancer cells. CuGI redirects the metabolic pathway of hypoxic cancer cells from anaerobic glycolysis to oxidative phosphorylation, thereby enhancing reactive oxygen species production and promoting oligomerization of lipoylated proteins in the tricarboxylic acid cycle. Through targeted induction of oxidative and proteotoxic stresses, CuGI induces apoptosis and cuproptosis specifically in cancer cells under hypoxic conditions while sparing normal cells. Moreover, cancer cell membrane-coated CuGI (CuGI@CM) exhibits enhanced tumor penetration effect and demonstrates commendable biocompatibility, effectively suppressing colorectal tumor growth. Importantly, CuGI@CM, when combined with vascular disruptors or radiotherapy which aggravate tumor hypoxia, synergistically potentiates therapeutic efficacy. Thus, CuGI represents a specific and potent nanotherapeutic capable of selectively eliminating hypoxic tumors, offering promise in combination therapies to address tumor hypoxia.

Potentiation of macrophage Piezo1 by atherogenic 7-ketocholesterol

The mechanosensitive ion channel Piezo1 present in endothelial and smooth muscle cells, as well as in macrophages, is emerging as a novel, important player in the etiology of atherosclerosis. Here, we show that myeloid-specific deficiency of Piezo1 in atherogenic Ldlr-/- mice reduces plaque formation. Moreover, chronic oxLDL, as well as its main oxysterol 7-ketocholesterol (7-KC), promotes Piezo1 opening by pressure stimulation in both mouse macrophages and transfected HEK cells. 7-KC dramatically enhances Piezo1 current amplitude and slows down inactivation and deactivation. This up-modulation involves an increase in Piezo1 expression, as well as a potentiation of mechanical gating that depends on membrane cholesterol depletion and decreased order. By contrast, Piezo1 is inhibited by the athero-protective free docosahexaenoic acid, either without or with 7-KC. Altogether, these findings indicate that macrophage Piezo1 is differentially modulated by pro- and anti-atherogenic lipids, pointing to the role of Piezo1 and its potentiation by oxysterols in atherosclerosis.

25-Hydroxycholesterol as a negative regulator of diaphragm muscle contractions via estrogen receptor and Ca2+ -dependent pathway

Cholesterol is involved in the regulation of various signaling processes, and oxysterols are essential lipid messengers. The cholesterol derivative 25-hydroxycholesterol (25-HC) is overproduced by muscle macrophages in sarcopenia, myasthenia, and neurodegenerative diseases. Herein, we examined the effects of 25-HC on Ca2+ signaling and contractions of the mouse diaphragm, the main respiratory muscle. We found that 25-HC increased resting levels of cytosolic Ca2+ in muscle fibers. This effect was dependent on estrogen receptor α (ERα) and was mediated by Ca2+-efflux from intracellular stores via dantrolene-insensitive and TMB-8-sensitive channels, presumably inositol trisphosphate receptors (IP3Rs). In addition, 25-HC suppressed diaphragm contractile responses to direct stimulation of the muscle fibers. The negative effect of 25-HC on contraction force was inhibited by blockers of ERα and Ca2+ mobilization. Thus, 25-HC may suppress diaphragm muscle contractility due to activation of an ERα/IP3R/Ca2+in axis in muscle fibers. At the same time, 25-HC did not significantly modify the contractions elicited by phrenic nerve stimulation and respiratory activity in vivo. We discuss that the previously found enhancement of neuromuscular transmission mediated by 25-HC in the diaphragm can compensate for the reduction in the muscle contractions in the case of phrenic nerve activation.

Advancing atherosclerosis research: The Power of lipid imaging with MALDI-MSI

Atherosclerosis is a chronic inflammatory disease that is one of the leading causes of mortality globally. It is characterized by the formation of atheromatous plaques in the intima layer of larger arteries. The (fibro-)fatty plaques usually develop asymptomatically within the vessel until a serious event such as myocardial infarction or stroke occurs. Lipids play a pivotal role in disease progression, but while the causal role of cholesterol is beyond doubt, the distribution of numerous other lipids within the heterogeneous layers of atherosclerotic plaques, and their biological function remain unclear. A deeper understanding of the pathophysiological progression of the disease for prognostics, diagnostics, treatment, and prevention is of great need. Mass spectrometry imaging (MSI), in particular with matrix-assisted laser desorption/ionization (MALDI) offers an unprecedented untargeted characterization of the physiological microenvironment, unraveling the spatial distribution of numerous biochemical compounds. MALDI-MSI offers an advantageous balance of sample preparation, chemical sensitivity, and spatial resolution, and thus has been established as a key technology in modern biomedical analysis. This review focuses on the analysis of lipids in atherosclerotic lesions with MALDI-MSI, for which the past years showed major developments in the spatial characterization of lipids and their interaction within atherosclerotic plaques. We will cover main contributions with a focus on the recent decade, elaborate possibilities, limitations, main findings, and recent developments from sample handling to instrumentation, and estimate current challenges and potentials of MALDI-MSI with respect to a clinical application.

Lipid metabolism, remodelling and intercellular transfer in the CNS

Lipid metabolism encompasses the catabolism and anabolism of lipids, and is fundamental for the maintenance of cellular homeostasis, particularly within the lipid-rich CNS. Increasing evidence further underscores the importance of lipid remodelling and transfer within and between glial cells and neurons as key orchestrators of CNS lipid homeostasis. In this Review, we summarize and discuss the complex landscape of processes involved in lipid metabolism, remodelling and intercellular transfer in the CNS. Highlighted are key pathways, including those mediating lipid (and lipid droplet) biogenesis and breakdown, lipid oxidation and phospholipid metabolism, as well as cell-cell lipid transfer mediated via lipoproteins, extracellular vesicles and tunnelling nanotubes. We further explore how the dysregulation of these pathways contributes to the onset and progression of neurodegenerative diseases, and examine the homeostatic and pathogenic impacts of environment, diet and lifestyle on CNS lipid metabolism.

Oxysterols Modulate Protein-Sterol Interactions to Impair CXCR4 Signaling in Aging Cells

Organismal aging is accompanied by the accumulation of senescent cells in the body, which drives tissue dysfunction. Senescent cells have a distinctive profile, including proliferation arrest, resistance to apoptosis, altered gene expression, and high inflammation. Despite global signaling and metabolic dysregulation during senescence, the underlying reasons for changes in signaling remain unclear. GPCRs are pivotal in cellular signaling, dynamically mediating the complex interplay between cells and their surrounding environment to maintain cellular homeostasis. The chemokine receptor CXCR4 plays a crucial role in modulating immune responses and inflammation. It has been shown that the expression of CXCR4 increases in cells undergoing senescence, which enhances inflammation postactivation. Here, we examine CXCR4 signaling in deeply senescent cells (aged cells), where cholesterol and its oxidized derivatives, oxysterols, affect receptor function. We report elevated oxysterol levels in senescent cells, which altered classical CXCL12-mediated CXCR4 signaling. Tail-oxidized sterols disrupted signaling more than ring-oxidized counterparts. Molecular dynamics simulations revealed that 27-hydroxycholesterol displaces cholesterol and binds strongly to alter the conformation of critical signaling residues, modifying the sterol-CXCR4 interaction landscape. Our study provides a molecular view of the observed mitigated GPCR signaling in the presence of oxysterols, which switched G-protein signaling from Gαi/o to Gαs class. Overall, we present an altered paradigm of GPCR signaling, where cholesterol oxidation alters the signaling outcome in aged cells.

In-depth proteomic profiling identifies potentiation of the LPS response by 7-ketocholesterol

In patients with stable coronary artery disease, plasma levels of 7-ketocholesterol (7-KC), found at high levels in atherosclerotic lesions, predict risk of incident heart failure dose dependently, potentially contributing to disease aetiology. Previous studies demonstrated that 7-KC can elicit effects on macrophage function; however, effects of 7-KC on the macrophage proteome have not been studied systematically. Here we used quantitative mass spectrometry to establish the effect of 7-KC on the mouse macrophage proteome. 7-KC independently mediated dynamic changes, including on atherogenic/M1 markers, cholesterol metabolism, biosynthesis and transport, as well as nutrient transport more broadly. These changes were however insufficient alone to drive changes in cytokine and chemokine secretion. Rather, they prime the macrophage, potentiating LPS-stimulated TNF alpha secretion and key pro-inflammatory enzymes. Our results indicate that 7-KC has independent metabolic effects on the macrophage; however, effects on the immune system are primarily due to the changes in metabolism priming the response to an inflammatory stimulus. Earlier findings from CANTOS and the recent FDA approval of colchicine highlight that inflammation is a viable target for cardiovascular disease; however, it is currrently unclear which will be the best anti-inflammatory targets to pursue in the future. In this context, our findings suggest that drugs targeting atherogenic markers induced by 7-KC might be well tolerated, as they will not necessarily be expected to be immunosuppressive.

Pexophagy and Oxidative Stress: Focus on Peroxisomal Proteins and Reactive Oxygen Species (ROS) Signaling Pathways

Peroxisomes generate reactive oxygen species (ROS) and also play a role in protecting cells from the damaging effects of such radicals. Dysfunctional peroxisomes are recognized by receptors and degraded by a selective type of macroautophagy called pexophagy. Oxidative stress is one of the signals that activates pexophagy through multiple signaling pathways. Conversely, impaired pexophagy results in the accumulation of damaged peroxisomes, which in turn leads to elevated ROS levels and oxidative stress, resulting as cellular dysfunction and the progression of diseases such as neurodegeneration, cancer, and metabolic disorders. This review explores the molecular mechanisms driving pexophagy and its regulation by oxidative stress with a particular focus on ROS. This highlights the role of peroxisomal proteins and ROS-mediated signaling pathways in regulating pexophagy. In addition, emerging evidence suggests that the dysregulation of pexophagy is closely linked to neurological disorders, underscoring its potential as a therapeutic target. Understanding the intricate crosstalk between pexophagy and oxidative stress provides new insights into the maintenance of cellular homeostasis and offers promising directions for addressing neurological disorders that are tightly associated with pexophagy and oxidative stress.

Dysregulation of lipid metabolism in the liver of Tspo knockout mice

The translocator protein, TSPO, has been implicated in a wide range of cellular processes exerted from its position in the outer mitochondrial membrane from where it influences lipid metabolism and mitochondrial oxidative activity. Understanding how this protein regulates a profusion of processes requires further elucidation and to that end we have examined lipid metabolism and used an RNAseq strategy to compare transcript abundance in wildtype and Tspo knockout (KO) mouse liver. The levels of cholesterol, triglyceride and phospholipid were significantly elevated in the KO mouse liver. The expression of cholesterol homeostasis genes was markedly downregulated. Determination of the differential expression revealed that many genes were either up- or downregulated in the KO animals. However, a striking observation within the results was a decrease of transcripts for protein degradation proteins in KO animals while protease inhibitors were enriched. When the entire abundance data-set was analysed with CEMiTool, and revealed a module of proteins that were under-represented in the KO animals. These could subsequently be formed into a network comprising three interlinked clusters at the centre of which were proteins of cytoplasmic ribosomes with gene ontology terms suggesting impairment to translation. The largest cluster was dominated by proteins of lipid metabolism but also contained disparate systems of iron metabolism and behaviour. The third cluster was dominated by proteins of the electron transport chain and oxidative phosphorylation. These findings suggest that TSPO contributes to lipid metabolism, detoxification of active oxygen species and oxidative phosphorylation, and regulates mitochondrial retrograde signalling.

Cyclodextrins: Establishing building blocks for AI-driven drug design by determining affinity constants in silico

Cyclodextrins (CDs) are cyclic carbohydrate polymers that hold significant promise for drug delivery and industrial applications. Their effectiveness depends on their ability to encapsulate target molecules with strong affinity and specificity, but quantifying affinities in these systems accurately is challenging for a variety of reasons. Computational methods represent an exceptional complement to in vitro assays because they can be employed for existing and hypothetical molecules, providing high resolution structures in addition to a mechanistic, dynamic, kinetic, and thermodynamic characterization. Here, we employ potential of mean force (PMF) calculations obtained from guided metadynamics simulations to characterize the 1:1 inclusion complexes between four different modified βCDs, with different type, number, and location of substitutions, and two sterol molecules (cholesterol and 7-ketocholesterol). Our methods, validated for reproducibility through four independent repeated simulations per system and different post processing techniques, offer new insights into the formation and stability of CD-sterol inclusion complexes. A systematic distinct orientation preference where the sterol tail projects from the CD's larger face and significant impacts of CD substitutions on binding are observed. Notably, sampling only the CD cavity's wide face during simulations yielded comparable binding energies to full-cavity sampling, but in less time and with reduced statistical uncertainty, suggesting a more efficient approach. Bridging computational methods with complex molecular interactions, our research enables predictive CD designs for diverse applications. Moreover, the high reproducibility, sensitivity, and cost-effectiveness of the studied methods pave the way for extensive studies of massive CD-ligand combinations, enabling AI algorithm training and automated molecular design.

Neurolipidomics in schizophrenia: A not so well-oiled machine

Most patients with schizophrenia (SCZ) do not exhibit violent behaviors and are more likely to be victims rather than perpetrators of violent acts. However, a subgroup of forensic detainees with SCZ exhibit tendencies to engage in criminal violations. Although numerous models have been proposed, ranging from substance use, serotonin transporter gene, and cognitive dysfunction, the molecular underpinnings of violence in SCZ patients remains elusive. Lithium and clozapine have established anti-aggression properties and recent studies have linked low cholesterol levels and ultraviolet (UV) radiation with human aggression, while vitamin D3 reduces violent behaviors. A recent study found that vitamin D3, omega-3 fatty acids, magnesium, and zinc lower aggression in forensic population. In this review article, we take a closer look at aryl hydrocarbon receptor (AhR) and the dysfunctional lipidome in neuronal membranes, with emphasis on cholesterol and vitamin D3 depletion, as sources of aggressive behavior. We also discuss modalities to increase the fluidity of neuronal double layer via membrane lipid replacement (MLR) and natural or synthetic compounds. This article is part of the Special Issue on "Personality Disorders".

Therapeutic potential of monoterpene molecules acts against 7KCh-mediated oxidative stress and neuroinflammatory amyloidogenic signalling pathways

Alzheimer's disease (AD) is a degenerative disorder characterised by amyloid-beta aggregates activated by the accumulation of lipid molecules and their derivatives, especially 7-ketocholesterol (7KCh), an oxidised lipid that plays a great part in the progression of AD. The current therapeutics need bio-potential molecules and their biomedical application preventing 7KCh-induced cytotoxicity. In this study, bornyl acetate (BA) and menthol (ME), the natural monoterpenes were investigated for their neuroprotective effects against 7KCh-induced SH-SY5Y cells and their effects were compared to the standard drug galantamine (GA). 7KCh-induced changes like lipid accumulation, amyloid generation, free radical generation, acetylcholinesterase levels, calcium accumulation and mitochondrial membrane integrity were analysed in SH-SY5Y cells with or without BA and ME treatment. Furthermore, various mediators involved in the amyloidogenic, inflammatory and apoptotic pathways were studied. In our results, the cells induced with 7KCh upon co-treatment with BA and ME significantly reduced lipid accumulation and amyloid generation through toll-like receptor (TLR) 4 suppression and enhanced ATP binding cassette (ABCA) 1-mediated clearance. Co-treatment with BA and ME concurrently regulated oxidative stress, acetylcholinesterase activity, mitochondrial membrane potential and intracellular calcification altered by 7KCh-induced SH-SY5Y cells. Moreover, 7KCh-induced cells showed elevated mRNA levels of misfolded protein markers and apoptotic mediators which were significantly downregulated by BA and ME co-treatment. In addition, the protein expression of amyloidogenic, proinflammatory as well as pro-apoptotic markers was decreased by BA and ME co-treatment in 7KCh-induced cells. Overall, BA and ME mediated inhibition of amyloidogenic activation and cell survival against 7KCh-induced inflammation, thereby preventing the onset and progression of AD in comparison to GA.

Impact of Physical Activity on Cellular Metabolism Across Both Neurodegenerative and General Neurological Conditions: A Narrative Review

BACKGROUND

Regular physical activity plays a crucial role in modulating cellular metabolism and mitigating the progression of neurodegenerative diseases such as Alzheimer's, Parkinson's, and Multiple Sclerosis.

OBJECTIVE

The objective of this review is to evaluate the molecular mechanisms by which exercise influences cellular metabolism, with a focus on its potential as a therapeutic intervention for neurological disorders.

METHODS

A comprehensive literature review was conducted using peer-reviewed scientific articles, with a focus on the period between 2015 and 2024, to analyze the effects of exercise on mitochondrial function, oxidative stress, and metabolic health.

RESULTS

The findings indicate that exercise promotes mitochondrial biogenesis, enhances oxidative phosphorylation, and reduces reactive oxygen species, contributing to improved energy production and cellular resilience. These metabolic adaptations are associated with delayed disease progression and reduced symptoms in patients with neurodegenerative conditions. Additionally, integrating exercise with nutritional strategies may further enhance therapeutic outcomes by addressing metabolic disturbances comprehensively.

CONCLUSIONS

This review concludes that personalized exercise protocols should be developed to optimize metabolic benefits for patients with neurological diseases, while future research should focus on biomarker development for individualized treatment approaches. These findings highlight the importance of non-pharmacological interventions in managing neurodegenerative diseases.

Spatially heterogeneous lipid dysregulation in tuberculous meningitis

Tuberculous (TB) meningitis is the deadliest form of extrapulmonary TB which disproportionately affects children and immunocompromised individuals. Studies in pulmonary TB have shown that Mycobacterium tuberculosis can alter host lipid metabolism to evade the immune system. Cholesterol lowering drugs (i.e., statins) reduce the risk of infection, making them a promising host-directed therapy in pulmonary TB. However, the effect of M. tuberculosis infection on the young or adult brain lipidome has not been studied. The brain is the second-most lipid-rich organ, after adipose tissue, with a temporally and spatially heterogeneous lipidome that changes from infancy to adulthood. The young, developing brain in children may be uniquely vulnerable to alterations in lipid composition and homeostasis, as perturbations in cholesterol metabolism can cause developmental disorders leading to intellectual disabilities. To begin to understand the alterations to the brain lipidome in pediatric TB meningitis, we utilized our previously published young rabbit model of TB meningitis and applied mass spectrometry (MS) techniques to elucidate spatial differences. We used matrix assisted laser desorption/ionization-MS imaging (MALDI-MSI) and complemented it with region-specific liquid chromatography (LC)-MS/MS developed to identify and quantify sterols and oxysterols difficult to identify by MALDI-MSI. MALDI-MSI revealed several sphingolipids, glycerolipids and glycerophospholipids that were downregulated in brain lesions. LC-MS/MS revealed the downregulation of cholesterol, several sterol intermediates along the cholesterol biosynthesis pathway and enzymatically produced oxysterols as a direct result of M. tuberculosis infection. However, oxysterols produced by oxidative stress were increased in brain lesions. Together, these results demonstrate significant spatially regulated brain lipidome dysregulation in pediatric TB meningitis.

The colonic polyphenol catabolite dihydroferulic acid (DHFA) regulates macrophages activated by oxidized LDL, 7-ketocholesterol, and LPS switching from pro- to anti-inflammatory mediators

Macrophage activation plays a central role in the development of atherosclerotic plaques. Interaction with oxidized low-density lipoprotein (oxLDL) leads to macrophage differentiation into foam cells and oxylipin production, contributing to plaque formation. 7-Ketocholesterol (7KC) is an oxidative byproduct of cholesterol found in oxLDL particles and is considered a factor contributing to plaque progression. During atherosclerotic lesion regression or stabilization, macrophages undergo a transformation from a pro-inflammatory phenotype to a reparative anti-inflammatory state. Interleukin-10 (IL-10) and PGE1 appear to be crucial in resolving both acute and chronic inflammatory processes. After coffee consumption, the gut microbiota processes non-absorbed chlorogenic acids producing various lower size phenolic acids. These colonic catabolites, including dihydroferulic acid (DHFA), may exert various local and systemic effects. We focused on DHFA's impact on inflammation and oxidative stress in THP-1 macrophages exposed to oxLDL, 7KC, and lipopolysaccharides (LPS). Our findings reveal that DHFA inhibits the release of several pro-inflammatory mediators induced by LPS in macrophages, such as CCL-2, CCL-3, CCL-5, TNF-α, IL-6, and IL-17. Furthermore, DHFA reduces IL-18 and IL-1β secretion in an inflammasome-like model. DHFA demonstrated additional benefits: it decreased oxLDL uptake and CD36 expression induced by oxLDL, regulated reactive oxygen species (ROS) and 8-isoprostane secretion (indicating oxidative stress modulation), and selectively increased IL-10 and PGE1 levels in the presence of inflammatory stimuli (LPS and 7KC). Finally, our study highlights the pivotal role of PGE1 in foam cell inhibition and inflammation regulation within activated macrophages. This study highlights DHFA's potential as an antioxidant and anti-inflammatory agent, particularly due to its ability to induce PGE1 and IL-10.

Lipidomic profiling in patients with familial hypercholesterolemia: Abnormalities in glycerolipids and oxysterols

OBJECTIVES AND AIM

This study aimed to identify precise biomarkers and develop targeted therapeutic strategies for preventing premature atherosclerotic cardiovascular disease in patients with familial hypercholesterolemia (FH) by investigating the quantitative and qualitative abnormalities in the metabolic network of lipids in these patients using an advanced lipidomics platform.

DESIGN & METHODS

The study population comprised 18 homozygous (HoFH), 18 heterozygous (HeFH) FH patients, and 20 healthy controls. Cholesterol oxidation products (oxysterol, COPs) and main lipid classes were determined using gas chromatography-mass spectrometry. Results were expressed as percentages of total fat matter for lipid classes and percentages of total COPs for oxysterols. The principal component analysis (PCA) was also carried out, to highlight the correlation between studied parameters and groups investigated.

RESULTS

Patients (both HoFH and HeFH) showed lower content of free fatty acids (FFAs) and greater values of triacylglycerols (TAGs) in comparison to controls. HoFH showed lower monoacylglycerols (P<0.01) and higher free cholesterol (FC) (P<0.05) when compared to HeFH and controls. The total content of COPs ranged from 1.96 to 4.25 mg/dL, from 2.27 to 4.05 mg/dL, and from 0.79 to 4.12 mg/dL in healthy controls, HoFH and HeFH groups, respectively, with no significant differences between patients and controls. In general, the 7α-hydroxycholesterol (7α-HC) was greater than other COPs. However, no significant differences were found between the three studied groups. Moreover, an opposite trend was observed between 7α-HC and 7-ketocholesterol (7-KC). Additionally, when PCA was carried out, the first two PCs explained 92.13 % of the total variance, of which the PC1 describes 53.94 % of variance mainly correlated to TAGs, diacylglycerols (DAGs), and 7-KC. On the other hand, the PC2 was correlated primarily for FFAs, FC and esterified sterols (E-STE).

CONCLUSIONS

In conclusion, abnormal levels of TAGs, DAGs and 7-KC were associated with HeFH while HoFH was associated with the abnormal amount of E-STE.

Oxidative stress and aging: synergies for age related diseases

Aging is characterized by a progressive decline in physiological function and underlies several disabilities, including the increased sensitivity of cells and tissues to undergo pathological oxidative stress. In recent years, efforts have been made to better understand the relationship between age and oxidative stress and further develop therapeutic strategies to minimize the impact of both events on age-related diseases. In this work, we review the impact of the oxidant and antioxidant systems during aging and disease development and discuss the crosstalk of oxidative stress and other aging processes, with a focus on studies conducted in elderly populations.

Multiomics to Characterize the Molecular Events Underlying Impaired Glucose Tolerance in FXR-Knockout Mice

The prevalence of different metabolic syndromes has grown globally, and the farnesoid X receptor (FXR), a metabolic homeostat for glucose, lipid, and bile acid metabolisms, may serve an important role in the progression of metabolic disorders. Glucose intolerance by FXR deficiency was previously reported and observed in our study, but the underlying biology remained unclear. To investigate the ambiguity, we collected the nontargeted profiles of the fecal metaproteome, serum metabolome, and liver proteome in Fxr-null (Fxr-/-) and wild-type (WT) mice with LC-HRMS. FXR deficiency showed a global impact on the different molecular levels we monitored, suggesting its serious disruption in the gut microbiota, hepatic metabolism, and circulating biomolecules. The network and enrichment analyses of the dysregulated metabolites and proteins suggested the perturbation of carbohydrate and lipid metabolism by FXR deficiency. Fxr-/- mice presented lower levels of hepatic proteins involved in glycogenesis. The impairment of glycogenesis by an FXR deficiency may leave glucose to accumulate in the circulation, which may deteriorate glucose tolerance. Lipid metabolism was dysregulated by FXR deficiency in a structural-dependent manner. Fatty acid β-oxidations were alleviated, but cholesterol metabolism was promoted by an FXR deficiency. Together, we explored the molecular events associated with glucose intolerance by impaired FXR with integrated novel multiomic data.

The DNA methylation status of the vitamin A signaling associated with testicular degeneration induced by long-day photoperiods in Magang geese

Magang geese are typical short-day breeders whose reproductive behaviors are significantly influenced by photoperiod. Exposure to a long-day photoperiod results in testicular regression and spermatogenesis arrest in Magang geese. To investigate the epigenetic influence of DNA methylation on the seasonal testicular regression in Magang geese, we conducted whole-genome bisulfite sequencing and transcriptome sequencing of testes across 3 reproductive phases during a long-day photoperiod. A total of 250,326 differentially methylated regions (DMR) were identified among the 3 comparison groups, with a significant number showing hypermethylation, especially in intronic regions of the genome. Integrating bisulfite sequencing with transcriptome sequencing data revealed that DMR-associated genes tend to be differentially expressed in the testes, highlighting a potential regulatory role for DNA methylation in gene expression. Furthermore, there was a significant negative correlation between changes in the methylation of CG DMRs and changes in the expression of their associated genes in the testes. A total of 3,359 DMR-associated differentially expressed genes (DEG) were identified; functional enrichment analyses revealed that motor proteins, MAPK signaling pathway, ECM-receptor interaction, phagosome, TGF-beta signaling pathway, and calcium signaling might contribute to the testicular regression process. GSEA revealed that the significantly enriched activated hallmark gene set was associated with apoptosis and estrogen response during testicular regression, while the repressed hallmark gene set was involved in spermatogenesis. Our study also revealed that methylation changes significantly impacted the expression level of vitamin A metabolism-related genes during testicular degeneration, with hypermethylation of STRA6 and increased calmodulin levels indicating vitamin A efflux during the testicular regression. These findings were corroborated by pyrosequencing and real-time qPCR, which revealed that the vitamin A metabolic pathway plays a pivotal role in testicular degeneration under long-day conditions. Additionally, metabolomics analysis revealed an insufficiency of vitamin A and an abnormally high level of oxysterols accumulated in the testes during testicular regression. In conclusion, our study demonstrated that testicular degeneration in Magang geese induced by a long-day photoperiod is linked to vitamin A homeostasis disruption, which manifests as the hypermethylation status of STRA6, vitamin A efflux, and a high level of oxysterol accumulation. These findings offer new insights into the effects of DNA methylation on the seasonal testicular regression that occurs during long-day photoperiods in Magang geese.

Lipolysis and Sterol Stability and Bioaccessibility of Wholemeal Rye Bread Enriched with Plant Sterols Subjected to Adult and Elderly Digestion Conditions

This study evaluated the impact of different digestion conditions (adult and senior) on lipolysis and bioaccessibility of plant sterols (PS) and phytosterol oxidation products (POPs) in PS-enriched wholemeal rye bread. Under adult digestion conditions, the addition of gastric lipase (GL) reduced lipolysis products (by 6.1% for free fatty acids and 11.7% for monoacylglycerols) and the bioaccessibility of PS by 6.7%, compared to the control. In digestion with both GL and cholesterol esterase (CE), these reductions were 12.9, 20.1, and 11.3%, respectively. Both modifications (GL and GL + CE) increased the bioaccessibility of POPs by 4.5-4.0%. When simulating the elderly digestion, the modified gastric and intestinal phases did not alter PS bioaccessibility but decreased POPs bioaccessibility by 21.8% compared to control, along with reduced lipolysis. Incorporating GL and CE thus approached physiological conditions and influenced lipid digestion. Elderly simulated digestion conditions resulted in a positive outcome by maintaining PS bioaccessibility while reducing potentially harmful POPs.

Mechanisms of ingested polystyrene micro-nanoplastics (MNPs) uptake and translocation in an in vitro tri-culture small intestinal epithelium

Micro and nanoplastics (MNPs) are now ubiquitous contaminants of food and water. Many cellular and animal studies have shown that ingested MNPs can breach the intestinal barrier to reach the circulation. To date however, the cellular mechanisms involved in intestinal absorption of MNPs have not been investigated with physiologically relevant models, and thus remain unknown. We employed in vitro simulated digestion, a tri-culture small intestinal epithelium model, and a panel of inhibitors to assess the contributions of the possible mechanisms to absorption of 26 nm carboxylated polystyrene (PS26C) MNPs. Inhibition of ATP synthesis reduced translocation by only 35 %, suggesting uptake by both active endocytic pathways and passive diffusion. Translocation was also decreased by inhibition of dynamin and clathrin, suggesting involvement of clathrin mediated endocytosis (CME) and fast endophilin-mediated endocytosis (FEME). Inhibition of actin polymerization also significantly reduced translocation, suggesting involvement of macropinocytosis or phagocytosis. However, inhibition of the Na+-H+ exchanger had no effect on translocation, thus ruling out macropinocytosis. Together these results suggest uptake by passive diffusion as well as by active phagocytosis, CME, and FEME pathways. Further studies are needed to assess uptake mechanisms for other environmentally relevant MNPs as a function of polymer, surface chemistry, and size.

Aging and "Age-Related" Diseases - What Is the Relation?

The study explores the intricate relationship between aging and the development of noncommunicable diseases [NCDs], focusing on whether these diseases are inevitable consequences of aging or primarily driven by lifestyle factors. By examining epidemiological data, particularly from hunter-gatherer societies, the study highlights that many NCDs prevalent in modern populations are rare in these societies, suggesting a significant influence of lifestyle choices. It delves into the mechanisms through which poor diet, smoking, and other lifestyle factors contribute to systemic physiological imbalances, characterized by oxidative stress, insulin resistance and hyperinsulinemia, and dysregulation of the sympathetic nervous system, the renin-angiotensin-aldosterone system, and the immune system. The interplay between this pattern and individual factors such as genetic susceptibility, biological variability, epigenetic changes and the microbiome is proposed to play a crucial role in the development of a range of age-related NCDs. Modified biomolecules such as oxysterols and advanced glycation end products also contribute to their development. Specific diseases such as benign prostatic hyperplasia, Parkinson's disease, glaucoma and osteoarthritis are analyzed to illustrate these mechanisms. The study concludes that while aging contributes to the risk of NCDs, lifestyle factors play a crucial role, offering potential avenues for prevention and intervention through healthier living practices. One possible approach could be to try to restore the physiological balance, e.g. through dietary measures [e.g. Mediterranean diet, Okinawan diet or Paleolithic diet] in conjunction with [a combination of] pharmacological interventions and other lifestyle changes.

FooDOxS: a database of oxidized sterols content in foods

Dietary oxidized sterols (DOxS) are cholesterol-like molecules known to exert pro-inflammatory, pro-oxidant, and pro-apoptotic effects, among others. We present the FooDOxS database, a comprehensive compilation of DOxS content in over 1680 food items from 120 publications across 25 countries, augmented by data generated by our group. This database reports DOxS content in foods classified under the NOVA and What We Eat in America (WWEIA) systems, allowing a comprehensive and statistically robust summary of DOxS content in foods. Notably, we evaluated the efficacy of using NOVA and WWEIA classifications in capturing DOxS variations across food categories. Our findings provide insights into the strengths and limitations of these classification systems, enhancing their utility for assessing dietary components. This research contributes to the understanding of DOxS in food processing and suggests refinements for classification systems, holding promise for improved food safety and public health assessments.

Characterization of Silybum marianum and Silybum eburneum seed oils: Phytochemical profiles and antioxidant properties supporting important nutritional interests

Milk thistle seed oil is still not a well-known edible oil. Silybum marianum (milk thistle), is present in several countries and is the only known representative of the genus Silybum. However, Silybum eburneum, which is an endemic plant in Spain, Kenya, Morocco, Algeria, and Tunisia, is considered a marginalized species. The present work is the first report that gives information on the lipid and phenolic profiles of Tunisian S. eburneum seed oil compared to those of Tunisian S. marianum seed oil. In addition, the antioxidant properties of these oils were determined with DPPH, FRAP, and KRL assays, and their ability to prevent oxidative stress was determined on human monocytic THP-1 cells. These oils are characterized by high amounts of unsaturated fatty acids; linoleic acid and oleic acid are the most abundant. Campesterol, sitosterol, stigmasterol, and β-amyrin were the major phytosterols identified. α-tocopherol was the predominant tocopherol found. These oils also contain significant amounts of phenolic compounds. The diversity and richness of Silybum marianum and Silybum eburneum seed oils in unsaturated fatty acids, phenolic compounds, and tocopherols are associated with high antioxidant activities revealed by the DPPH, FRAP, and KRL assays. In addition, on THP-1 cells, these oils powerfully reduced the oxidative stress induced by 7-ketocholesterol and 7β-hydroxycholesterol, two strongly pro-oxidant oxysterols often present at increased levels in patients with age-related diseases. Silybum marianum and Silybum eburneum seed oils are therefore important sources of bioactive molecules with nutritional interest that prevent age-related diseases, the frequency of which is increasing in all countries due to the length of life expectancy.

Retinal toxicity of heavy metals and its involvement in retinal pathology

The objective of the present review is to discuss epidemiological evidence demonstrating the association between toxic metal (Cd, Pb, Hg, As, Sn, Ti, Tl) exposure and retinal pathology, along with the potential underlying molecular mechanisms. Epidemiological studies demonstrate that Cd, and to a lesser extent Pb exposure, are associated with age-related macular degeneration (AMD), while the existing evidence on the levels of these metals in patients with diabetic retinopathy is scarce. Epidemiological data on the association between other toxic metals and metalloids including mercury (Hg) and arsenic (As), are limited. Clinical reports and laboratory in vivo studies have shown structural alterations in different layers of retina following metal exposure. Examination of retina samples demonstrate that toxic metals can accumulate in the retina, and the rate of accumulation appears to increase with age. Experimental studies in vivo and in vitro studies in APRE-19 and D407 cells demonstrate that toxic metal exposure may cause retinal damage through oxidative stress, apoptosis, DNA damage, mitochondrial dysfunction, endoplasmic reticulum stress, impaired retinogenesis, and retinal inflammation. However, further epidemiological as well as laboratory studies are required for understanding the underlying molecular mechanisms and identifying of the potential therapeutic targets and estimation of the dose-response effects.

Chemical Composition, Nutritional, and Biological Properties of Extracts Obtained with Different Techniques from Aronia melanocarpa Berries

This study investigates the chemical composition, nutritional, and biological properties of extracts obtained from A. melanocarpa berries using different extraction methods and solvents. Hydrodistillation and supercritical fluid extraction with CO2 allowed us to isolate fruit essential oil (HDEX) and fixed oil (SFEEX), respectively. A phenol-enriched extract was obtained using a mild ultrasound-assisted maceration with methanol (UAMM). The HDEX most abundant component, using gas chromatography-mass spectrometry (GC/MS), was italicene epoxide (17.2%), followed by hexadecanoic acid (12.4%), khusinol (10.5%), limonene (9.7%), dodecanoic acid (9.7%), and (E)-anethole (6.1%). Linoleic (348.9 mg/g of extract, 70.5%), oleic (88.9 mg/g, 17.9%), and palmitic (40.8 mg/g, 8.2%) acids, followed by α-linolenic and stearic acids, were the main fatty acids in SFEEX determined using high-performance liquid chromatography coupled with a photodiode array detector and an evaporative light scattering detector (HPLC-DAD/ELSD). HPLC-DAD analyses of SFEEX identified β-carotene as the main carotenoid (1.7 mg/g), while HPLC with fluorescence detection (FLU) evidenced α-tocopherol (1.2 mg/g) as the most abundant tocopherol isoform in SFEEX. Liquid chromatography-electrospray ionization-MS (LC-ESI-MS) analysis of UAMM showed the presence of quercetin-sulfate (15.6%, major component), malvidin 3-O-(6-O-p-coumaroyl) glucoside-4-vinylphenol adduct (pigment B) (9.3%), di-caffeoyl coumaroyl spermidine (7.6%), methyl-epigallocatechin (5.68%), and phloretin (4.1%), while flavonoids (70.5%) and phenolic acids (23.9%) emerged as the most abundant polyphenol classes. UAMM exerted a complete inhibition of the cholesterol oxidative degradation at 140 °C from 75 μg of extract, showing 50% protection at 30.6 μg (IA50). Furthermore, UAMM significantly reduced viability (31-48%) in A375 melanoma cells in the range of 500-2000 μg/mL after 96 h of incubation (MTT assay), with a low toxic effect in normal HaCaT keratinocytes. The results of this research extend the knowledge of the nutritional and biological properties of A. melanocarpa berries, providing useful information on specific extracts for potential food, cosmetic, and pharmaceutical applications.

Selenomethionine in gelatin methacryloyl hydrogels: Modulating ferroptosis to attenuate skin aging

During skin aging, the degeneration of epidermal stem cells (EpiSCs) leads to diminished wound healing capabilities and epidermal disintegration. This study tackles this issue through a comprehensive analysis combining transcriptomics and untargeted metabolomics, revealing age-dependent alterations in the Gpx gene family and arachidonic acid (AA) metabolic networks, resulting in enhanced ferroptosis. Selenomethionine (Se-Met) could enhance GPX4 expression, thereby assisting EpiSCs in countering AA-induced mitochondrial damage and ferroptosis. Additionally, Se-Met demonstrates antioxidative characteristics and extensive ultraviolet absorption. For the sustained and controllable release of Se-Met, it was covalently grafted to UV-responsive GelMA hydrogels via AC-PEG-NHS tethers. The Se-Met@GelMA hydrogel effectively accelerated wound healing in a chronological aging mice model, by inhibiting lipid peroxidation and ferroptosis with augmented GPX4 expression. Moreover, in a photoaging model, this hydrogel significantly mitigated inflammatory responses, extracellular matrix remodeling, and ferroptosis in UV-exposed mice. These characteristics render Se-Met@GelMA hydrogel valuable in practical clinical applications.

Possible interactions between selected food processing and medications

The impact of food processing on drug absorption, metabolism, and subsequent pharmacological activity is a pressing yet insufficiently explored area of research. Overlooking food-processing-drug interactions can significantly disrupt optimal clinical patient management. The challenges extend beyond merely considering the type and timing of food ingestion as to drug uptake; the specific food processing methods applied play a pivotal role. This study delves into both selected thermal and non-thermal food processing techniques, investigating their potential interference with the established pharmacokinetics of medications. Within the realm of thermal processing, conventional methods like deep fat frying, grilling, or barbecuing not only reduce the enteric absorption of drugs but also may give rise to side-products such as acrylamide, aldehydes, oxysterols, and oxyphytosterols. When produced in elevated quantities, these compounds exhibit enterotoxic and pro-inflammatory effects, potentially impacting the metabolism of various medications. Of note, a variety of thermal processing is frequently adopted during the preparation of diverse traditional herbal medicines. Conversely, circumventing high heat through innovative approaches (e.g., high-pressure processing, pulsed electric fields, plasma technology), opens new avenues to improve food quality, efficiency, bioavailability, and sustainability. However, it is crucial to exercise caution to prevent the excessive uptake of active compounds in specific patient categories. The potential interactions between food processing methods and their consequences, whether beneficial or adverse, on drug interactions can pose health hazards in certain cases. Recognizing this knowledge gap underscores the urgency for intensified and targeted scientific inquiry into the multitude of conceivable interactions among food composition, processing methods, and pharmaceutical agents. A thorough investigation into the underlying mechanisms is imperative. The complexity of this field requires substantial scrutiny and collaborative efforts across diverse domains, including medicine, pharmacology, nutrition, food science, food technology, and food engineering.

The "Hit and Run" Hypothesis for Alzheimer's Disease Pathogenesis

Alzheimer's disease (AD) is a devastating neurodegenerative disorder affecting millions worldwide. Emerging research has challenged the conventional notion of a direct correlation between amyloid deposition and neurodegeneration in AD. Recent studies have suggested that amyloid and Tau deposition act as a central nervous system (CNS) innate immune driver event, inducing chronic microglial activation that increases the susceptibility of the AD brain to the neurotoxicity of infectious insults. Although modifiable risk factors account for up to 50% of AD risk, the mechanisms by which they interact with the core process of misfolded protein deposition and neuroinflammation in AD are unclear and require further investigation. This update introduces a novel perspective, suggesting that modifiable risk factors act as external insults that, akin to infectious agents, cause neurodegeneration by inducing recurrent acute neurotoxic microglial activation. This pathological damage occurs in AD pathology-primed regions, creating a "hit and run" mechanism that leaves no discernible pathological trace of the external insult. This model, highlighting microglia as a pivotal player in risk factor-mediated neurodegeneration, offers a new point of view on the complex associations of modifiable risk factors and proteinopathy in AD pathogenesis, which may act in parallel to the thoroughly studied amyloid-driven Tau pathology, and strengthens the therapeutic rationale of combining immune modulation with tight control of risk factor-driven insults.

Phytol from Scoparia dulcis prevents NF-κB-mediated inflammatory responses during macrophage polarization

Macrophages are primary immune cells that mediate a wide range of inflammatory diseases through their polarization potential. In this study, phytol isolated from Scoparia dulcis has been explored against 7-ketocholesterol and bacterial lipopolysaccharide-induced macrophage polarization in IC-21 cells. Isolated phytol has been characterized using GC-MS, TLC, HPTLC, FTIR, 1H-NMR, and HPLC analyses. The immunomodulatory effects of viable concentrations of phytol were tested on oxidative stress, arginase activity, nuclear and mitochondrial membrane potentials in IC-21 cells in addition to the modulation of calcium and lipids. Further, gene and protein expression of atherogenic markers were studied. Results showed that the isolated phytol at a viable concentration of 400 µg/ml effectively reduced the production of nitric oxide, superoxide anion (ROS generation), calcium and lipid accumulation, stabilized nuclear and mitochondrial membranes, and increased arginase activity. The atherogenic markers including iNOS, COX-2, IL-6, IL-1β, MMP-9, CD36, and NF-κB were significantly downregulated at the levels of gene and protein expression, while macrophage surface and nuclear receptor markers (CD206, CD163, and PPAR-γ) were significantly upregulated by phytol pre-treatment in macrophages. Therefore, the present pharmacognostic study supports the role of phytol isolated from Scoparia dulcis in preventing M2-M1 macrophage polarization under inflammatory conditions, making it a promising compound.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03924-9.

Cytoprotective effects of α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol on 7-ketocholesterol - Induced oxiapoptophagy: Major roles of PI3-K / PDK-1 / Akt signaling pathway and glutathione peroxidase activity in cell rescue

On murine N2a cells, 7-ketocholesterol induced an oxiapotophagic mode of cell death characterized by oxidative stress (reactive oxygen species overproduction on whole cells and at the mitochondrial level; lipid peroxidation), apoptosis induction (caspase-9, -3 and -7 cleavage, PARP degradation) and autophagy (increased ratio LC3-II / LC3-I). Oxidative stress was strongly attenuated by diphenyleneiodonium chloride which inhibits NAD(P)H oxidase. Mitochondrial and peroxisomal morphological and functional changes were also observed. Down regulation of PDK1 / Akt signaling pathways as well as of GSK3 / Mcl-1 and Nrf2 pathways were simultaneously observed in 7-ketocholesterol-induced oxiapoptophagy. These events were prevented by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol. The inhibition of the cytoprotection by LY-294002, a PI3-K inhibitor, demonstrated an essential role of PI3-K in cell rescue. The rupture of oxidative stress in 7-ketocholesterol-induced oxiapoptophagy was also associated with important modifications of glutathione peroxidase, superoxide dismutase and catalase activities as well as of glutathione peroxidase-1, superoxide dismutase-1 and catalase level and expression. These events were also counteracted by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol. The inhibition of the cytoprotection by mercaptosuccinic acid, a glutathione peroxidase inhibitor, showed an essential role of this enzyme in cell rescue. Altogether, our data support that the reactivation of PI3-K and glutathione peroxidase activities by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol are essential to prevent 7KC-induced oxiapoptophagy.

Effect of 7-ketocholesterol incorporation on substrate binding affinity and turnover rate of the organic cation transporter 2 (OCT2)

The organic cation transporter 2 (OCT2) is pivotal in the renal elimination of several positively charged molecules. OCT2 mode of transport is profoundly influenced by the level of membrane cholesterol. The aim of this study was to investigate the effect of oxidized cholesterol on OCT2 transport activity in human embryonic kidney 293 cells stably transfected with OCT2 (OCT2-HEK293) and in primary renal proximal tubular epithelial cells (RPTEC). Cholesterol was exchanged with 7-ketocholesterol, the main product of cholesterol auto-oxidation, by exposing cells to sterol-saturated methyl-β-cyclodextrin (mβcd). After a 30 min-exposure, approximately 50% of the endogenous cholesterol was replaced by 7-ketocholesterol without significant changes in total sterol level. In the presence of 7-ketocholesterol, [3H]1-methyl-4-phenylpyridinium (MPP+) uptake was significantly reduced in both cell lines. 7-ketocholesterol incorporation did not affect lipid raft integrity, nor OCT2 surface expression and spatial organization. The inhibitory effect of 7-ketocholesterol on MPP+ uptake was abolished by the presence of MPP+ in the trans-compartment. In the presence of 7-ketocholesterol, both Kt and Vmax of MPP+ influx decreased. Molecular docking using OCT2 structure in outward occluded conformation showed overlapping poses and similar binding energies between cholesterol and 7-ketocholesterol. The thermal stability of OCT2 was not changed when cholesterol was replaced with 7-ketocholesterol. We conclude that 7-ketocholesterol confers a higher rigidity to the carrier by reducing its conformational entropy, arguably as a result of changes in plasma membrane physical properties, thereby facilitating the achievement of a higher affinity state at the expense of the mobility and overall cycling rate of the transporter.

Addressing the complexities in measuring cyclodextrin-sterol binding constants: A multidimensional study

A class of cyclodextrin (CD) dimers has emerged as a potential new treatment for atherosclerosis; they work by forming strong, soluble inclusion complexes with oxysterols, allowing the body to reduce and heal arterial plaques. However, characterizing the interactions between CD dimers and oxysterols presents formidable challenges due to low sterol solubility, the synthesis of modified CDs resulting in varying number and position of molecular substitutions, and the diversity of interaction mechanisms. To address these challenges and illuminate the nuances of CD-sterol interactions, we have used multiple orthogonal approaches for a comprehensive characterization. Results obtained from three independent techniques - metadynamics simulations, competitive isothermal titration calorimetry, and circular dichroism - to quantify CD-sterol binding are presented. The objective of this study is to obtain the binding constants and gain insights into the intricate nature of the system, while accounting for the advantages and limitations of each method. Notably, our findings demonstrate ∼1000× stronger affinity of the CD dimer for 7-ketocholesterol in comparison to cholesterol for the 1:1 complex in direct binding assays. These methodologies and findings not only enhance our understanding of CD dimer-sterol interactions, but could also be generally applicable to prediction and quantification of other challenging host-guest complex systems.

Effect of PCSK9 inhibition on plasma levels of small dense low density lipoprotein-cholesterol and 7-ketocholesterol

BACKGROUND

Oxidized forms of cholesterol (oxysterols) are implicated in atherogenesis and can accumulate in the body via direct absorption from food or through oxidative reactions of endogenous cholesterol, inducing the formation of LDL particles loaded with oxidized cholesterol. It remains unknown whether drastic reductions in LDL-cholesterol (LDL-C) are associated with changes in circulating oxysterols and whether small dense LDL (sdLDL) are more likely to carry these oxysterols and susceptible to the effects of PCSK9 inhibition (PCSK9i).

OBJECTIVE

We investigate the effect of LDL-C reduction accomplished via PCSK9i on changes in plasma levels of sdLDL-cholesterol (sdLDL-C) and a common, stable oxysterol, 7-ketocholesterol (7-KC), among 134 patients referred to our Preventive Cardiology clinic.

METHODS

Plasma lipid panel, sdLDL-C, and 7-KC measurements were obtained from patients before and after initiation of PCSK9i.

RESULTS

The intervention caused a significant lowering of LDL-C (-55.4 %). The changes in sdLDL-C levels (mean reduction 51.4 %) were highly correlated with the reductions in LDL-C levels (R = 0.829, p < 0.001). Interestingly, whereas changes in plasma free 7-KC levels with PCSK9i treatment were much smaller than (-6.6 %) and did not parallel those of LDL-C and sdLDL-C levels, they did significantly correlate with changes in triglycerides and very low-density lipoprotein-cholesterol (VLDL-C) levels (R = 0.219, p = 0.025).

CONCLUSION

Our findings suggest a non-preferential clearance of LDL subparticles as a consequence of LDL receptor upregulation caused by PCSK9 inhibition. Moreover, the lack of significant reduction in 7-KC with PCSK9i suggests that 7-KC may be in part carried by VLDL and lost during lipoprotein processing leading to LDL formation.

Role of Brain Liver X Receptor in Parkinson's Disease: Hidden Treasure and Emerging Opportunities

Parkinson's disease (PD) is a neurodegenerative disease due to the degeneration of dopaminergic neurons (DNs) in the substantia nigra (SN). The liver X receptor (LXR) is involved in different neurodegenerative diseases. Therefore, the objective of the present review was to clarify the possible role of LXR in PD neuropathology. LXRs are the most common nuclear receptors of transcription factors that regulate cholesterol metabolism and have pleiotropic effects, including anti-inflammatory effects and reducing intracellular cholesterol accumulation. LXRs are highly expressed in the adult brain and act as endogenous sensors for intracellular cholesterol. LXRs have neuroprotective effects against the development of neuroinflammation in different neurodegenerative diseases by inhibiting the expression of pro-inflammatory cytokines. LXRs play an essential role in mitigating PD neuropathology by reducing the expression of inflammatory signaling pathways, neuroinflammation, oxidative stress, mitochondrial dysfunction, and enhancement of BDNF signaling.In conclusion, LXRs, through regulating brain cholesterol homeostasis, may be effectual in PD. Also, inhibition of node-like receptor pyrin 3 (NLRP3) inflammasome and nuclear factor kappa B (NF-κB) by LXRs could effectively prevent neuroinflammation in PD. Taken together, LXRs play a crucial role in PD neuropathology by inhibiting neuroinflammation and associated degeneration of DNs.

In Vitro Evaluation of the Effects of 7-Ketocholesterol and 7β-Hydroxycholesterol on the Peroxisomal Status: Prevention of Peroxisomal Damages and Concept of Pexotherapy

7-Ketocholesterol and 7β-hydroxycholesterol are most often derived from the autoxidation of cholesterol. Their quantities are often increased in the body fluids and/or diseased organs of patients with age-related diseases such as cardiovascular diseases, Alzheimer's disease, age-related macular degeneration, and sarcopenia which are frequently associated with a rupture of RedOx homeostasis leading to a high oxidative stress contributing to cell and tissue damages. On murine cells from the central nervous system (158N oligodendrocytes, microglial BV-2 cells, and neuronal N2a cells) as well as on C2C12 murine myoblasts, these two oxysterols can induce a mode of cell death which is associated with qualitative, quantitative, and functional modifications of the peroxisome. These changes can be revealed by fluorescence microscopy (apotome, confocal microscopy), transmission electron microscopy, flow cytometry, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and gas chromatography-coupled with mass spectrometry (GC-MS). Noteworthy, several natural molecules, including ω3 fatty acids, polyphenols, and α-tocopherol, as well as several Mediterranean oils [argan and olive oils, Milk-thistle (Sylibum marianum) and Pistacia lenticus seed oils], have cytoprotective properties and attenuate 7-ketocholesterol- and 7β-hydroxycholesterol-induced peroxisomal modifications. These observations led to the concept of pexotherapy.

Role of Oxysterols in Ocular Degeneration Mechanisms and Involvement of P2X7 Receptor

Ocular degeneration, including cataracts, glaucoma, macular degeneration, and diabetic retinopathy, is a major public health challenge, as it affects the quality of life of millions of people worldwide and, in its advanced stages, leads to blindness. Ocular degeneration, although it can affect different parts of the eye, shares common characteristics such as oxysterols and the P2X7 receptor. Indeed, oxysterols, which are cholesterol derivatives, are associated with ocular degeneration pathogenesis and trigger inflammation and cell death pathways. Activation of the P2X7 receptor is also linked to ocular degeneration and triggers the same pathways. In age-related macular degeneration, these two key players have been associated, but further studies are needed to extrapolate this interrelationship to other ocular degenerations.

Cholesterol Oxidation Products: Potential Adverse Effect and Prevention of Their Production in Foods

Cholesterol oxidation products (COPs) are a group of substances formed during food processing. COPs in diet is a health concern because they may affect human health in association with the risk of various diseases including atherosclerosis, Alzheimer's disease, age-related macular degeneration, diabetes, and chronic gastrointestinal inflammatory colitis. Production of COPs in foods can be affected by many factors such as temperature, pH, light, oxygen, water, carbohydrates, fatty acids, proteins, and metal cations. The key issue is preventing its generation in foods. Some COPs can also be produced in vivo by both nonenzymatic and enzymatic-catalyzed oxidation reactions. Currently, a number of natural antioxidants such as catechins, flavonoids, and other polyphenols have been proven to inhibit the generation of COPs. In addition, measures taken during food processing can also minimize the production of COPs, such as the Maillard reaction and marinating food with plant polyphenol-rich seasonings. In conclusion, a comprehensive approach encompassing the suppression on COPs generation and implementation of processing measures is imperative to safeguard human health against the production of COPs in the food chain.

Sitosterol-rich Digera muricata against 7-ketocholesterol and lipopolysaccharide-mediated atherogenic responses by modulating NF-ΚB/iNOS signalling pathway in macrophages

Digera muricata L., commonly known as Tartara, is an edible herb used as traditional medicine in many countries of Africa and Asia. This study aimed to elucidate the effect of a phytosterol-rich extract of D. muricata on 7-ketocholesterol-mediated atherosclerosis in macrophages. The extract was examined by phytochemical analyses, GC-MS, TLC, DPPH scavenging and hRBC membrane stabilization assays. Macrophage polarization was studied with experimental groups framed based on alamar blue cell viability and griess assays. Regulations of arginase enzyme activity, ROS generation, mitochondrial membrane potential, cell membrane integrity, pinocytosis, lipid uptake and peroxidation, as well as, intracellular calcium deposition were determined. In addition, expressions of atherogenic mediators were analysed using PCR, ELISA and immunocytochemistry techniques. Diverse phytochemicals with higher free radical scavenging activity and anti-inflammatory potential have been detected in the D. muricata. Co-treatment with D. muricata markedly reduced the atherogenic responses induced by 7KCh in the presence of LPS such as ROS, especially, NO and O2- along with lipid peroxidation. Furthermore, D. muricata significantly normalized mitochondrial membrane potential, cell membrane integrity, pinocytic activity, intracellular lipid accumulation and calcium deposition. These results provided us with the potentiality of D. muricata in ameliorating atherogenesis. Additionally, it decreased the expression of pro-atherogenic mediators (iNOS, COX-2, MMP9, IL-6, IL-1β, CD36, CD163 and TGFβ1) and increased anti-atherogenic mediators (MRC1 and PPARγ) with high cellular expressions of NF-κB and iNOS. Results showed the potential of sitosterol-rich D. muricata as a versatile biomedical therapeutic agent against abnormal macrophage polarization and its associated pathologies.

Cholesterol-autoxidation metabolites in host defense against infectious diseases

Cholesterol plays essential roles in biological processes, including cell membrane stability and myelin formation. Cholesterol can be metabolized to oxysterols by enzymatic or nonenzymatic ways. Nonenzymatic cholesterol metabolites, also called cholesterol-autoxidation metabolites, are formed dependent on the oxidation of reactive oxygen species (ROS) such as OH• or reactive nitrogen species, such as ONOO- . Cholesterol-autoxidation metabolites are abundantly produced in diseases such as inflammatory bowel disease and atherosclerosis, which are associated with oxidative stress. Recent studies have shown that cholesterol-autoxidation metabolites can further regulate the immune system. Here, we review the literature and summarize how cholesterol-autoxidation metabolites, such as 25-hydroxycholesterol (25-OHC), 7α/β-OHC, and 7-ketocholesterol, deal with the occurrence and development of infectious diseases through pattern recognition receptors, inflammasomes, ROS production, nuclear receptors, G-protein-coupled receptor 183, and lipid availability. In addition, we include the research regarding the roles of these metabolites in COVID-19 infection and discuss our viewpoints on the future research directions.

7β-Hydroxycholesterol and 7-ketocholesterol: New oxidative stress biomarkers of sarcopenia inducing cytotoxic effects on myoblasts and myotubes

Aging is a complex biological process which can be associated with skeletal muscle degradation leading to sarcopenia. The aim of this study consisted i) to determine the oxidative and inflammatory status of sarcopenic patients and ii) to clarify the impact of oxidative stress on myoblasts and myotubes. To this end, various biomarkers of inflammation (C-reactive protein (CRP), TNF-α, IL-6, IL-8, leukotriene B4 (LTB4)) and oxidative stress (malondialdehyde, conjugated dienes, carbonylated proteins and antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase) as well as oxidized derivatives of cholesterol formed by cholesterol autoxidation (7-ketocholesterol, 7β-hydroxycholesterol), were analyzed. Apelin, a myokine which contributes to muscle strength, was also quantified. To this end, a case-control study was conducted to evaluate the RedOx and inflammatory status in 45 elderly subjects (23 non-sarcopenic; 22 sarcopenic) from 65 years old and higher. SARCopenia-Formular (SARC-F) and Timed Up and Go (TUG) tests were used to distinguish between sarcopenic and non-sarcopenic subjects. By using red blood cells, plasma and/or serum, we observed in sarcopenic patients an increased activity of major antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase) associated with lipid peroxidation and protein carbonylation (increased level of malondialdehyde, conjugated dienes and carbonylated proteins). Higher levels of 7-ketocholesterol and 7β-hydroxycholesterol were also observed in the plasma of sarcopenic patients. Significant differences were only observed with 7β-hydroxycholesterol. In sarcopenic patients comparatively to non-sarcopenic subjects, significant increase of CRP, LTB4 and apelin were observed whereas similar levels of TNF-α, IL-6 and IL-8 were found. The increased plasma level of 7-ketocholesterol and 7β-hydroxycholesterol in sarcopenic patients led us to study the cytotoxic effect of these oxysterols on undifferentiated (myoblasts) and differentiated (myotubes) murine C2C12 cells. With the fluorescein diacetate and sulforhodamine 101 assays, an induction of cell death was observed both on undifferentiated and differentiated cells: the cytotoxic effects were less pronounced with 7-ketocholesterol. In addition, IL-6 secretion was never detected whatever the culture conditions, TNF-α secretion was significantly increased on undifferentiated and differentiated C2C12 cells treated with 7-ketocholesterol- and 7β-hydroxycholesterol, and IL-8 secretion was increased on differentiated cells. 7-ketocholesterol- and 7β-hydroxycholesterol-induced cell death was strongly attenuated by α-tocopherol and Pistacia lentiscus L. seed oil both on myoblasts and/or myotubes. TNF-α and/or IL-8 secretions were reduced by α-tocopherol and Pistacia lentiscus L. seed oil. Our data support the hypothesis that the enhancement of oxidative stress observed in sarcopenic patients could contribute, especially via 7β-hydroxycholesterol, to skeletal muscle atrophy and inflammation via cytotoxic effects on myoblasts and myotubes. These data bring new elements to understand the pathophysiology of sarcopenia and open new perspectives for the treatment of this frequent age-related disease.

Accumulation of oxysterols in the erythrocytes of COVID-19 patients as a biomarker for case severity

BACKGROUND

Due to the high risk of COVID-19 patients developing thrombosis in the circulating blood, atherosclerosis, and myocardial infarction, it is necessary to study the lipidome of erythrocytes. Specifically, we examined the pathogenic oxysterols and acylcarnitines in the erythrocyte homogenate of COVID-19 patients. These molecules can damage cells and contribute to the development of these diseases.

METHODS

This study included 30 patients and 30 healthy volunteers. The erythrocyte homogenate extract was analyzed using linear ion trap mass spectrometry combined with high-performance liquid chromatography. The concentrations of oxysterols and acylcarnitines in erythrocyte homogenates of healthy individuals and COVID-19 patients were measured. Elevated levels of toxic biomarkers in red blood cells could initiate oxidative stress, leading to a process known as Eryptosis.

RESULTS

In COVID-19 patients, the levels of five oxysterols and six acylcarnitines in erythrocyte homogenates were significantly higher than those in healthy individuals, with a p-value of less than 0.05. The mean total concentration of oxysterols in the red blood cells of COVID-19 patients was 23.36 ± 13.47 μg/mL, while in healthy volunteers, the mean total concentration was 4.92 ± 1.61 μg/mL. The 7-ketocholesterol and 4-cholestenone levels were five and ten times higher, respectively, in COVID-19 patients than in healthy individuals. The concentration of acylcarnitines in the red blood cell homogenate of COVID-19 patients was 2 to 4 times higher than that of healthy volunteers on average. This finding suggests that these toxic biomarkers may cause the red blood cell death seen in COVID-19 patients.

CONCLUSIONS

The abnormally high levels of oxysterols and acylcarnitines found in the erythrocytes of COVID-19 patients were associated with the severity of the cases, complications, and the substantial risk of thrombosis. The concentration of oxysterols in the erythrocyte homogenate could serve as a diagnostic biomarker for COVID-19 case severity.

Prognostic value of plasma 7-ketocholesterol in sepsis

BACKGROUND

Early evaluation of the severity of sepsis and estimation of its prognosis remains one of the main challenges in current therapeutic strategies. This study aimed to evaluate the prognostic value of plasma 7-ketocholesterol (7-KC) in sepsis.

METHODS

We retrospectively measured by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) the plasma 7-KC concentration in 176 patients with sepsis and 90 healthy volunteers. A multivariate Cox proportional hazard model was introduced to identify independent factors, including plasma 7-KC and clinical features, for the 28-day mortality of sepsis, and a nomogram for predicting the 28-day mortality of sepsis was established. Decision curve analysis (DCA) was performed to assess the prediction model of death risk of sepsis.

RESULTS

The area under the curve (AUC) of plasma 7-KC in diagnosing sepsis was 0.899 (95% CI = 0.862-0.935, P < 0.001), while it was 0.830 (95% CI = 0.764-0.894, P < 0.001) in diagnosing septic shock. The AUCs of plasma 7-KC in predicting the survival of sepsis patients in the training cohort and the test cohort were 0.770 (95% CI = 0.692-0.848, P < 0.05) and 0.869 (95% CI = 0.763-0.974, P < 0.05), respectively. In addition, high plasma 7-KC expression predicts poor prognosis in sepsis. Then, 7-KC and platelet count were identified as the two factors with significant differences by a multivariate Cox proportional hazard model, and the 28-day mortality probability ranged from 0.002 to 0.985 and was assessed using a nomogram. DCA results revealed that the combination of plasma 7-KC and platelet count showed the best prognostic efficiency of the risk threshold compared to a single factor in both the training cohort and test cohort.

CONCLUSIONS

Collectively, the elevated plasma 7-KC level is an indicator of sepsis and was identified as a prognostic indicator for sepsis patients, providing a landscape for predicting survival in early sepsis with potential clinical utility.

Oncolytic viruses engineered to enforce cholesterol efflux restore tumor-associated macrophage phagocytosis and anti-tumor immunity in glioblastoma

The codependency of cholesterol metabolism sustains the malignant progression of glioblastoma (GBM) and effective therapeutics remain scarce. In orthotopic GBM models in male mice, we identify that codependent cholesterol metabolism in tumors induces phagocytic dysfunction in monocyte-derived tumor-associated macrophages (TAMs), resulting in disease progression. Manipulating cholesterol efflux with apolipoprotein A1 (ApoA1), a cholesterol reverse transporter, restores TAM phagocytosis and reactivates TAM-T cell antitumor immunity. Cholesterol metabolomics analysis of in vivo-sorted TAMs further reveals that ApoA1 mediates lipid-related metabolic remodeling and lowers 7-ketocholesterol levels, which directly inhibits tumor necrosis factor signaling in TAMs through mitochondrial translation inhibition. An ApoA1-armed oncolytic adenovirus is also developed, which restores antitumor immunity and elicits long-term tumor-specific immune surveillance. Our findings provide insight into the mechanisms by which cholesterol metabolism impairs antitumor immunity in GBM and offer an immunometabolic approach to target cholesterol disturbances in GBM.

Cholesterol Metabolism in Aging and Age-Related Disorders

All mammalian cell membranes contain cholesterol to maintain membrane integrity. The transport of this hydrophobic lipid is mediated by lipoproteins. Cholesterol is especially enriched in the brain, particularly in synaptic and myelin membranes. Aging involves changes in sterol metabolism in peripheral organs and also in the brain. Some of those alterations have the potential to promote or to counteract the development of neurodegenerative diseases during aging. Here, we summarize the current knowledge of general principles of sterol metabolism in humans and mice, the most widely used model organism in biomedical research. We discuss changes in sterol metabolism that occur in the aged brain and highlight recent developments in cell type-specific cholesterol metabolism in the fast-growing research field of aging and age-related diseases, focusing on Alzheimer's disease. We propose that cell type-specific cholesterol handling and the interplay between cell types critically influence age-related disease processes.