Journal of Lipid Research

ObjectiveGlucokinase Regulatory Protein (GKRP) controls the activity of Glucokinase (GCK) to regulate liver glucose uptake and storage. Coding variants in GCKR, the gene encoding GKRP, strongly associate with fatty liver disease, hypertriglyceridemia, and hypercholesterolemia. Here, we sought to investigate the mechanisms by which a common GKRP variant affects hepatic lipid and cholesterol metabolism. MethodsWe developed mouse models to examine how the human GKRP P446L variant influences liver and systemic metabolism. Endogenous Gckr expression was ablated in adult mouse hepatocytes, together with re-expression of either human GKRP P446L or the reference GKRP protein. We assessed body weight, adiposity, systemic glucose homeostasis, and hepatic metabolites in mice expressing reference GKRP or GKRP P446L under multiple metabolic conditions. To determine whether the effects of GKRP P446L may result from reduced GCK activity, we analyzed mice with liver-specific deletion of Gck. ResultsHepatic expression of GKRP P446L resulted in reduced GKRP and GCK protein levels and elevated serum cholesterol. Hepatic deletion of Gck in mice recapitulated several effects of GKRP P446L, including increased hepatic cholesterol and triglyceride content. The elevated cholesterol was associated with increased cholesterogenic gene expression and cholesterol synthesis. Hepatic expression of an alternative hexokinase (HKII) normalized the effects of GCK-deficiency, suggesting that impaired glucose phosphorylation underlies the phenotype. ConclusionsThe GKRP P446L variant reduced GKRP protein abundance, and diminished GCK activity while increasing cholesterol levels. Loss of GCK elevated cholesterol and hepatic triglyceride levels. Collectively, these findings demonstrate that GCK suppresses hepatic cholesterol synthesis and lipid accumulation, suggesting that reduced GCK activity underlies the metabolic abnormalities associated with the GKRP P446L variant. HighlightsO_LIThe GKRP P446L variant reduces GKRP protein abundance and diminishes GCK activity. C_LIO_LIExpression of GKRP P446L in mouse hepatocytes increases serum cholesterol levels. C_LIO_LIHepatic GCK activity suppresses cholesterogenic gene expression and cholesterol synthesis. C_LI

Age-related macular degeneration is a common ocular disease that causes vision loss in the elderly, with a complex set of risk factors and proposed mechanisms of pathogenesis. A powerful method for investigating changes in disease is metabolomics, by which small molecules can be identified and quantified simultaneously. We report here the metabolic analysis of human RPE-choroid tissue in aging and macular degeneration (AMD), as well as comparisons of human macular and extramacular RPE-choroid and neural retina. Levels of 215 metabolites were determined in young donors, AMD donors (early/intermediate, geographic atrophy, and neovascularization) and age-matched controls. The largest number of metabolite differences were observed between young and healthy aged controls, as opposed to between aged controls and any stage of AMD. Two notable metabolites found to be increased in aging choroids are trimethylamine N-oxide and uric acid, both of which were significant after Bonferroni correction. A mouse endothelial cell line treated with a high concentration of uric acid exhibited reduced migration in a wound closure assay. This study provides initial insights into the metabolome of human choroids in varying states of age and macular degeneration, as well as functional implications of these changes in the aging choroid.

Cholesterol is a key component of cellular membranes, regulating membrane organization, fluidity, and signaling. However, cholesterol analysis remains technically challenging, as no single method currently allows both accurate quantification and spatially resolved visualization. Biochemical assays provide accurate quantification but lack spatial resolution, whereas imaging strategies can perturb membrane organization or cholesterol accessibility. Here, we describe optimized protocols using fluorescent D4 probes derived from the cholesterol-binding domain of perfringolysin O (D4-mCherry and D4-GFP) to detect, visualize, and quantify cholesterol in biological samples. We detail procedures for probe production, purification, and application, and establish conditions that ensure robust and reproducible labeling of membrane-accessible cholesterol. By combining fluorescence-based imaging with quantitative analysis, this approach enables the assessment of cholesterol distribution while preserving its native membrane environment. The proposed methodology provides a versatile and reliable framework for studying cholesterol in a wide range of experimental systems.

SignificanceQuantifying lipid droplet (LD) remodeling in 3D hepatic organoids is often limited to endpoint staining or phototoxic live fluorescence imaging, thereby obscuring droplet-level kinetics. AimWe aimed to develop a label-free method to track LD dynamics in living hepatic organoids under different fatty-acid loads. ApproachTime-lapse 3D refractive-index tomograms were acquired using holotomography and analyzed with a depth-adaptive, multi-threshold segmentation pipeline to quantify LD number, volume, sphericity, and refractive-index-derived concentration and dry mass at single-droplet resolution. ResultsOleic acid and linoleic acid induced LD accumulation while preserving organoid integrity, whereas palmitic acid triggered rapid structural collapse. Despite increases in total LD burden under both oleic acid and linoleic acid, droplet-level dynamics diverged: oleic acid produced volume-dominated accumulation via enlargement of fewer LDs and increased size heterogeneity, whereas linoleic acid produced number-dominated accumulation via sustained increases in LD number, yielding a more uniform population of small droplets. ConclusionsLabel-free holotomography with depth-adaptive analysis enables non-invasive, longitudinal, and multi-scale quantification of LD dynamics in intact organoids and reveals fatty-acid- dependent temporal modes of lipid storage. Statement of DiscoveryWe developed a label-free, longitudinal 3D holotomography framework with depth-adaptive lipid droplet segmentation that quantifies single-droplet dynamics in living mouse hepatic organoids. Using this platform, we found that oleic acid and linoleic acid induce LD accumulation via distinct strategies--oleic acid via droplet enlargement and linoleic acid via sustained increases in droplet number--while palmitic acid rapidly compromises organoid integrity.

BackgroundElevated postprandial hypertriglyceridemia (PP-HTG) is a significant risk factor for development of cardiovascular diseases, however, the mechanisms underlying its exaggerated rise remains poorly understood. MicroRNAs (miRs) are known to be implicated in the regulation of lipid metabolism, thus identifying them as potential key players. We presently investigated whether miRs may control postprandial triglyceride (PP-TG) response. MethodsPostprandial changes in circulating miR expression as a function of the degree of postprandial TG response were evaluated in non-dyslipidemic healthy subjects (n=32). The impact of miR-100-5p on hepatic gene expression was evaluated in differentiated Caco2 and HepG2 cells by analysis of hepatic transcriptome (RNAseq), western blot and ELISA. In vivo studies were conducted in C57BL/6J mice overexpressing mimic miR-100-5p. ResultsPostprandial variation in circ-miR-100-5p levels inversely correlate with PP-TG response. Cir-miR-100-5p was preferentially associated with TGRL particles of intestinal origin in subjects exhibited a low PP TG response. Differential analysis of transcriptome from HepG2 cells transfected by either mimic miR-100-5p or scrambled mimic miR as control allowed us to identify PCSK9 as a down-regulated gene. Overexpression of miR-100-5p in HepG2 cells significantly decreased PCSK9 mRNA levels by 52% (p<0.0001), cellular protein content by 28 % (p<0.0001) as well as PCSK9 secretion by 39% (p<0.0001). In vivo systemic delivery of mimic miR-100-5p induced a two-fold reduction (p<0.0001) on PP-TG in mice, such effect being abolished by blocking the circulating form of PCSK9 with alirocumab. Finally, we revealed a significant inverse relationship between circulating miR-100-5p expression levels and both PCSK9 levels and the magnitude of postprandial hypertriglyceridemia. ConclusionTaken together, our observations reveal that miR-100-5p regulates postprandial hypertriglyceridemia by targeting PCSK9, thus enhancing hepatic triglyceride-rich lipoproteins (TGRL) uptake. Our findings allow us to propose circ-miR-100-5p as a potential biomarker for early identification of subjects at high cardiovascular risk, prior to appearance of classical clinical features of metabolic disorders. Postprandial clinical study, HDL-PP (NCT03109067) Lay summaryThis study examined whether miRs may control postprandial triglyceride response Key findingsOur data reveal that miR-100-5p regulates postprandial hypertriglyceridemia by targeting PCSK9 Our observations allow us to propose miR-100-5p as a potential biomarker for early identification of subjects at high cardiovascular risk

Metabolic dysfunction-associated steatohepatitis (MASH) is associated with increased expression of peroxisome proliferator-activated receptor gamma (PPAR{gamma}, Pparg) and reduced expression of genes involved in methionine metabolism in the liver. The nuclear receptor PPAR{gamma} is activated by fatty acids, and the knockout of Pparg in hepatocytes (Pparg{Delta}Hep) reduced the negative effects of MASH on methionine metabolism. Here, we sought to determine whether hepatocyte Pparg is required for the transcriptional regulation of genes involved in hepatic methionine metabolism in conditions with altered fatty acid flux to the liver: fasting, refeeding, and high-fat diet (HFD)-induced obesity/steatosis. Fasting induced liver steatosis and increased the expression of key genes involved in the methionine metabolism in the liver, while 6h-refeeding reversed these effects and reduced the expression of phosphatidylethanolamine N-methyltransferase (Pemt) and cystathionine beta synthase (Cbs). Overall, fasting and refeeding did not alter hepatocyte Pparg expression nor Pparg{Delta}Hep affected fasting and refeeding-mediated regulation of methionine metabolism gene expression. Diet-induced steatosis reduced hepatic Pemt expression in control (Pparg-intact) mice, and the thiazolidinedione (TZD)-mediated activation of PPAR{gamma} in diet-induced obese control (Pparg-intact) mice reduced the expression of betaine homocysteine S-methyltransferase (Bhmt) and Cbs. However, diet-induced steatosis increased hepatocyte Pparg expression, and Pparg{Delta}Hep blocked the negative effects of HFD and TZD on hepatic methionine metabolism. The PPAR{gamma}-dependent reduction of hepatic Bhmt and Cbs expression was confirmed in mouse primary hepatocytes. Taken together, hepatocyte Pparg may serve as a negative regulator of hepatic methionine metabolism in diet-induced obese mice and these actions could contribute to promoting the onset of MASH.

The liver is widely considered to be one of the most conserved organs amongst vertebrates, with it being involved in blood detoxification, bile production and the metabolism of xenobiotic compounds. Liver organoids have previously been derived from several species and used as models of drug metabolism, toxicity, and fundamental tissue biology. To date, however, these models have not been developed from ruminant species, specifically cattle and sheep. Here we present the first report of the development and comprehensive characterisation of bovine and ovine liver organoids derived from primary liver tissue. When initially established, organoids from both species were comprised of KRT19- and KRT18-positive cholangiocytes. The capacity for organoids to differentiate into hepatocyte-enriched cultures was evaluated and it was noted that there was an increase in hepatocyte markers in bovine cultures. A comparative analysis of the liver tissue and organoids of both species revealed species-specific differences in gene expression, which were conserved within organoid cultures. Most notably, bovine liver tissue and organoids had enriched expression of genes associated with fatty acid uptake and storage whereas ovine samples had higher expression of genes associated with fatty acid conversion, highlighting fundamental differences between these two ruminant species. Differences in expression of cytochrome P450 family genes were identified alongside those associated with an inflammatory response specifically in bovine samples, whereas ovine samples had higher expression of genes associated with a protective immune response. Despite this, transcriptomic analysis of organoids from both species, cultured in both growth and differentiation media, revealed preserved expression of genes associated with key liver functions, including gluconeogenesis and xenobiotic metabolism. Transcripts associated with the flavin-containing monooxygenases (FMO) family were expressed in both organoid growth media and organoid development media (OGM and ODM respectively), and both species could metabolise triclabendazole into its primary metabolite triclabendazole sulfoxide, therefore validating the potential of the organoids to be applied as in vitro models of metabolism and/or toxicity. Overall, this study provides novel insights into differences in liver composition and function between ruminant species, as well as providing novel experimental models of the liver for both cattle and sheep.

Inositols are a family of cyclic sugar alcohols comprising nine stereoisomers. Myo-inositol is the most abundant isomer found in humans and has been studied most extensively. It plays an important role in osmoregulation and is incorporated into membrane-anchored phosphatidylinositols. Scyllo-inositol is the second most abundant inositol isomer in the human brain and aberrant concentrations are associated with various diseases; however, its biological functions remain poorly understood. Here, the development and application of [13C6]scyllo-inositol as an isotopic tracer to study its metabolism is reported. A concise and robust synthetic route was established to obtain [13C6]scyllo-inositol from [13C6]myo-inositol in good yield. The uptake of [13C6]scyllo-inositol and responses of endogenous inositol isomers were measured in multiple cell lines by HILIC-MS/MS, showcasing the advantages of isotopic tracing. [13C6]scyllo-inositol proved to be a versatile isotopic tracer, when coupled with MS-based lipidomics and 2D NMR experiments. These experiments provide evidence that scyllo-inositol is incorporated into phosphatidylinositols in different cell lines. The results suggest a previously underappreciated role of scyllo-inositol in mammalian cells. The utilization of [13C6]scyllo-inositol will help to elucidate the role of scyllo-inositol metabolism in healthy and diseased states. SignificanceScyllo-inositol is a cyclic sugar alcohol found predominantly in the human brain. Changes in its concentration are associated with different diseases, and scyllo-inositol has been investigated as a potential drug against Alzheimers disease in clinical trials. However, its metabolic fate in mammalian cells is not well understood. We report here a synthetic strategy to obtain [13C6]scyllo-inositol and demonstrate, through isotopic tracing, its incorporation into phosphatidylinositols in different human-derived cell lines. This new stable isotopic tracer enables the investigation of the biological role of scyllo-inositol in mammals and beyond. HighlightsO_LIConcise synthesis of [13C6]scyllo-inositol C_LIO_LI[13C6]scyllo-inositol uptake and response of endogenous inositol isomers studied in multiple cell lines C_LIO_LIUse of [13C6]scyllo-inositol as an isotopic tracer in metabolomics and lipidomics experiments C_LIO_LIEvidence for scyllo-inositol incorporation into phosphatidylinositol in mammalian cells C_LI

Pentosan polysulfate (PPS) is a semisynthetic sulfated polysaccharide that was approved by the United States Food and Drug Administration (FDA) for treatment of interstitial cystitis (IC). A 2018 study by our group described a vision-threatening macular toxicity associated with long-term use of PPS. However, given the relatively recent characterization of PPS maculopathy, we have limited knowledge of its pathophysiology. The present study therefore investigated the pathophysiology of PPS maculopathy in a cell culture model, assessing impacts of PPS exposure on morphology and mitochondrial function. We treated ARPE-19 cells with increasing doses of PPS and investigated both mitoprotective and cytoprotective mechanisms, mitochondrial reactive oxygen species production (ROS) and respiration, cellular structure, and retinal pigment epithelium (RPE) dysfunction through phagocytosis assays. We found that PPS increased mitochondrial superoxide accumulation and that increased doses of PPS impaired basal and maximal respiration in a Seahorse assay without the expected response of increases in the cellular energy sensor pAMPK. PPS exposure disrupted mitochondrial and cell protective mechanisms against ROS accumulation as assessed through examination of mitochondrial biogenesis markers PGC-1 and SIRT1 and autophagy markers LC3 and p62. PINK1 expression increased with increasing duration of exposure to PPS. Further, we found that PPS led to functional and structural changes to RPE cells, which exhibited an increase in cell aspect ratio and impaired phagocytosis with higher doses of PPS. Lastly, we found an increase in cell death in response to higher doses of PPS, evident through ethidium homodimer cell viability assays. Taken together, our study shows PPS exposure has profound effects on RPE viability and function through impairment of mitochondrial respiration and mito- and cyto-protective mechanisms and highlights mitochondrial insult as a potential focus of future PPS research.

PurposeMitochondrial dysfunction contributes to major blinding diseases, including age-related macular degeneration and glaucoma. Although mitochondrial transplantation has shown therapeutic potential in multiple organ systems, translation to the eye remains limited, partly due to uncertainty regarding optimal delivery. We summarize the biologic rationale and preclinical evidence supporting ocular mitochondrial transplantation and present feasibility data evaluating clinically relevant delivery routes. MethodsWe conducted a focused narrative review of ocular mitochondrial transplantation. For feasibility experiments, mitochondria with an endogenous fluorescent dye were isolated from liver donor mice. Postnatal day 7 pups received subretinal injections, and adult CD1 mice received intravitreal injections, including optic nerve head directed delivery. Eyes were analyzed using fluorescence microscopy and immunohistochemistry. Mitochondrial uptake was assessed in cultured retinal pigmental epithelial (RPE) cells using co-incubation assays. Suprachoroidal delivery feasibility was evaluated in cadaveric human near-real surgical specimens using a novel dedicated suprachoroidal injector. ResultsThe literature on ocular mitochondrial transplantation remains limited and consists primarily of small preclinical studies using intravitreal delivery and imaging-based detection. In our experiments, intravitreal delivery produced donor signals predominantly within inner retinal layers, with enrichment along retinal nerve fiber bundles when directed toward the optic nerve head. Cultured RPE cells demonstrated dose-dependent uptake of exogenous mitochondria. Subretinal delivery localized donors signal to the RPE and adjacent outer retina. Suprachoroidal injections demonstrated procedural feasibility with reliable access to the suprachoroidal space and visible injectate distribution. ConclusionsOcular mitochondrial transplantation is in an early stage of investigation. Our feasibility data indicate that established posterior-segment delivery routes expose distinct retinal compartments and that route selection strongly influences anatomic distribution. Further studies are needed to verify intracellular uptake, define dosing and durability, and evaluate safety in disease-relevant models.

BACKGROUNDInactivation of ANGPTL3 (angiopoietin-like protein 3, A3) is a proven therapeutic strategy for lowering plasma lipid levels independently of the LDL receptor (LDLR), yet the optimal approach to inactivate A3 remains unclear. A3 is proteolytically cleaved and circulates as full-length (A3-FL), N-terminal (A3-Nter) and C-terminal (A3-Cter) fragments. The specific contribution of each form of A3, and of its paralog, ANGPTL8 (A8), in modulating circulating levels of ApoB-Containing Lipoproteins (ABCLs) remain poorly defined. Clarifying these relationships will inform next-generation A3-directed therapies. METHODSWe performed liver perfusion studies to directly compare the number and composition of VLDL particles secreted from mice with and without A3. To amplify effects on cholesterol metabolism, we generated Ldlr-/- mice expressing wildtype A3 (A3-WT), A3-FL or A3-Nter, with or without co-expression of A8, and analyzed plasma lipids, circulating A3 and A8 complexes, and intravascular lipase activities. Complementary in vitro assays and structural modeling were used to assess relative endothelial lipase (EL) inhibition by A3 alone or in complex with A8. RESULTSLiver perfusion studies revealed that A3 inactivation does not alter the rates of hepatic secretion of VLDL in wildtype or Ldlr-/- mice. Inactivation of A8 alone lowered plasma LDL-cholesterol (C) levels by [~]20%, an effect dependent upon the expression of both EL and A3. Maximal inhibition of lipoprotein lipase (LPL) required co-expression of A8 plus both A3-FL and A3-Nter, indicating that A3 cleavage, in addition to A8 expression, is essential for maximal LPL inhibition. In contrast, A8 expression, but not A3 cleavage, was required for optimal EL inhibition. CONCLUSIONSA8 acts in concert with A3 to differentially modulate LPL- and EL-mediated lipolysis, which antagonizes hepatic clearance of newly-secreted atherogenic ABCLs. This mechanistic framework refines our understanding of A3-targeted lipid lowering and highlights the therapeutic potential of dual A3- plus A8-directed strategies to treat dyslipidemia and prevent atherosclerotic cardiovascular disease. Clinical perspectiveO_ST_ABSWhat is new?C_ST_ABSO_LIInactivation of A3 lowers circulating ABCL levels without altering hepatic secretion rates of VLDL-ApoB or -TG. C_LIO_LIProteolytic cleavage of A3 is required for maximal inhibition of LPL. C_LIO_LIInactivation of A8 lowers LDL-C levels through an A3- and EL-dependent, but LDLR-independent, mechanism. C_LI What are the clinical implications?O_LICombining A8 inhibition with A3-inactivating therapies offers a strategy to achieve greater reduction in LDL-C levels and atherosclerotic cardiovascular risk. C_LI

BackgroundCarnitine plays an obligatory role in energetics owing to its role in the translocation of long-chain fatty acids into the mitochondrion for oxidation. Here, we determined the metabolic and behavioral consequences of systemic carnitine deficiency (SCD) in mice. MethodsFemale C57BL/6J mice were randomized to receive normal drinking water (control, n = 8) or drinking water supplemented with mildronate 4g.L-1 (mildronate, n = 8) for 21 days. Body composition was assessed at baseline and post treatment. Metabolic and behavioral phenotyping was performed continuously over 72 hours following 14 days of control or mildronate treatment. Stable isotope were used to assess whole-body substrate oxidation. Carnitine subfractions were quantified in skeletal muscle and liver, as was mitochondrial respiratory function. Liver and muscle samples also underwent proteomic analysis. ResultsMildronate treatment depleted total carnitine in muscle and liver by [~]97% (P < 0.001) and [~]90% (P < 0.001), respectively. Carnitine depletion was accompanied by lower total energy expenditure (P = 0.01), attributable to lower voluntary wheel running (P = 0.01). Oxidation rates of palmitate (P < 0.01) but not octanoate were lower whereas rates of glucose oxidation were greater in carnitine depleted mice (P < 0.01). Mitochondrial respiratory capacity was unaltered by carnitine deficiency. Carnitine deficiency remodeled muscle and liver proteomes to support lipid oxidation and energy production. SummaryIn mice, carnitine deficiency is characterized by decreased long-chain fatty acid oxidation despite preserved mitochondrial respiratory capacity. Carnitine deficiency resulted in lower voluntary exercise and a concomitant reduction in energy expenditure.

The modern Western diet (MWD) provides high linoleic acid (LA) exposure, typically contributing 6-9% of total caloric intake. These high LA levels have fueled a longstanding debate regarding whether this dietary pattern confers benefit or risk. Importantly, LA intake is disproportionately elevated among lower socioeconomic populations due to greater reliance on industrial seed oils and ultra-processed foods. Despite decades of research, controlled dietary intervention studies directly evaluating the biological consequences of varying LA exposure remain limited. The current randomized, double-blind intervention compared the effects of a 12-week Low LA diet (2.5% energy) versus a High LA diet (10.0% energy) in healthy adults. Primary outcomes included plasma highly unsaturated fatty acid (HUFA) concentrations and ex vivo zymosan-stimulated whole-blood oxylipin generation. Fifty- two participants completed the intervention. High LA exposure resulted in a marked reduction in plasma n-3 eicosapentaenoic acid (EPA) concentrations compared with the LowLA arm. In contrast, levels of arachidonic acid (ARA), dihomo-gamma-linolenic acid (DGLA) and docosahexaenoic acid (DHA) did not differ by dietary LA exposure. Analysis of oxylipin species revealed that levels of EPA-derived relative to ARA-derived mediators were significantly reduced in the High LA arm. These findings reveal that higher dietary LA selectively suppresses EPA pools and EPA-derived oxylipins without altering ARA, shifting the lipid mediator balance toward a more n-6-dominant profile.

BackgroundThis study was designed to investigate the relationship between visceral fat metabolic score (METS-VF), lipid accumulation product (LAP), visceral adiposity index (VAI) and thyroid function. MethodsUtilizing data from the National Health and Nutrition Examination Survey (NHANES) 2007-2012, participants were excluded if they lacked data on METS-VF, LAP, VAI or thyroid function, or were under 18 years of age. Multiple linear regression, smooth curve fitting, and subgroup analyses were performed to determine the independent relationship between lipid accumulation and thyroid function. ResultsAfter full covariate adjustment, all three visceral adiposity indices showed significant positive associations with FT3 (LAP: {beta}=0.028, VAI: {beta}=0.024, METS-VF: {beta}=0.026; all P<0.001), FT3/FT4 ratio, TT3, TT4, and TgAb. LAP and VAI demonstrated inverse associations with FT4 ({beta}=-0.218 and -0.183, respectively; both P<0.001), while VAI and METS-VF were positively associated with TSH ({beta}=0.149, P=0.041; {beta}=0.167, P=0.025). Quartile analyses confirmed dose-dependent relationships, with Q4 participants showing elevated FT3, FT3/FT4, TT3, TT4, and reduced FT4 compared to Q1. RCS analyses revealed distinct non-linear patterns: LAP exhibited non-linearity with FT3, TSH, TT3, and TT4 (all P-nonlinear<0.05) but linear inverse associations with FT4. VAI displayed reverse L-shaped curves for FT3, TSH, and TT3 with plateaus at higher levels, while TT4 showed an inverted U-shape. METS-VF demonstrated non-linear increases for FT3 and TT3, linear associations with TSH and TT4, and an inverted U-curve for FT4. Stratified analyses identified age, race, and smoking as consistent modifiers of FT3/FT4 associations across all indices (interaction P<0.05), with stronger effects in younger/older adults, males, White participants, and high-income groups. TT3 and TT4 modification patterns varied by index. Thyroid autoantibodies showed minimal associations across all indices. ConclusionVisceral lipid accumulation is closely associated with thyroid dysfunction, and this association exhibits significant non-linear characteristics, which are modulated by factors such as age, race, and lifestyle habits. These findings provide new perspectives for the early identification and intervention of obesity-related thyroid dysfunction.

BackgroundSex-related differences in cardiovascular disease suggest the presence of intrinsic vasoprotective mechanisms, with estrogen recognized as an important modulator of endothelial function. Building on existing evidence, the present study provides mechanistic insights into how estrogen and nitric oxide (NO) signaling regulate selective pathways of oxLDL uptake, mitochondrial dynamics, and inflammatory responses during early atherogenesis. MethodsWe combined an in vitro endothelial cell-macrophage co-culture model with in vivo studies in low-density lipoprotein receptor-knockout (LDLr-/-) mice to investigate the role of estrogen in early atherosclerotic processes. Human aortic endothelial cells (HAECs) were exposed to oxidized low-density lipoprotein (oxLDL) in the presence or absence of 17{beta}-estradiol (E2) and the nitric oxide (NO*) donor S-nitroso-N-acetylcysteine (SNAC). Key outcomes included oxLDL uptake, mitochondrial oxidative stress, mitochondrial dynamics, and inflammatory signaling. In vivo, male and female LDLr-/- mice were exposed to a short-term high-fat diet with or without SNAC treatment. Plasma lipid levels, blood pressure, aortic lesion formation, and cardiac remodeling were evaluated. ResultsE2 reduced oxLDL uptake and oxidative stress, effects recapitulated by SNAC; however, these responses involved distinct entry pathways, with E2 preferentially modulating lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) dependent uptake and SNAC targeting caveolae-associated mechanisms. In parallel, both E2 and SNAC reduced Scavenger Receptor Class B Type 1 (SR-B1) expression, suggesting an additional modulation on oxLDL transcytosis via this mechanism. Endothelial cells exposed to oxLDL exhibited altered mitochondrial regulatory proteins, including superoxide dismutase 2 (SOD-2), dynamin-related protein 1 (Drp-1), and optic atrophy protein 1 (OPA-1). Despite reducing oxidative stress, E2 increased the expression of adhesion molecules and enhanced monocyte adhesion in response to oxLDL exposure, particularly when combined with SNAC. Strikingly, E2 also modulated macrophage responses, increasing interleukin receptor antagonist (IL-1ra) expression and reducing GDF15, macrophage inhibitory factor (MIF), macrophage inflammatory protein 3 alfa (MIP-3), and matrix metalloproteinase 9 (MMP-9) levels, consistent with a less pro-inflammatory macrophage profile. In vivo, HFD increased plasma lipid levels and atherosclerotic lesion area in LDLr-/- mice, whereas SNAC partially attenuated these effects without affecting plasma lipid levels. In vivo, female LDLr-/- mice developed approximately 50% smaller aortic lesions than males, despite comparable or higher plasma lipid levels. A dyslipidemia led to increased blood pressure and a hypertensive phenotype in both males and females. SNAC treatment reduced lesion burden in both sexes and prevented diet-induced hypertension in females. ConclusionEstrogen limits early atherogenic injury by reducing endothelial uptake of oxLDL, preserving mitochondrial homeostasis, and modulating inflammatory signaling. Together, the E2 and NO pathways regulate early atherosclerosis through distinct yet complementary mechanisms, offering a potential framework for vascular-protective strategies.

Age-related macular degeneration (AMD) is a common, complex disease affecting older individuals that can lead to severe vision loss. It is characterized by early anatomical changes in the retina, retinal pigment epithelium (RPE), and choroid, especially in the central (macular) region. AMD can progress to severe atrophy and/or pathologic angiogenesis that leads to visual decline. Over 30 genetic loci have been identified as contributing to AMD risk; however, the mechanisms by which genetic variants affect pathology has not been thoroughly explored. In this report we examined single-nucleus gene expression in the retina, RPE and choroid of 88 individuals categorized by AMD stage, as well as 37 previously published samples. Genotyping was performed on 1.8 million SNPs, with additional SNPs imputed, on each donor to identify expression quantitative trait loci (eQTLs). We found that two AMD-risk loci (PILRB and ARMS2/HTRA1) affected the expression of PILRB and HTRA1, respectively. The risk allele of PILRB was associated with increased PILRB RNA in cones, fibroblasts, choroidal macrophages, and RPE, whereas the HTRA1 risk locus was associated with decreased HTRA1 RNA in the RPE. We also identified an age-related decrease in complement inhibitors in the choriocapillaris, a tissue susceptible to complement mediated damage in AMD.

PurposeHyperosmolar stress (HOS) is a major contributor to corneal epithelial cell damage in dry eye disease. We have previously shown that HOS damages mitochondria and impairs cell metabolism in corneal epithelial cells. Small extracellular vesicles (sEVs) are cell-derived lipid envelopes that are present in all body fluids, including tears. Prior studies suggest that sEV release and composition may be linked with changes in cell metabolism. In this study, we tested the effects of HOS on sEV release and composition, and found that sEV cargo may reflect early, underlying changes in dry eye disease. MethodsTelomerase-immortalized human corneal epithelial (hTCEpi) cells were treated with 450 mOsm NaCl for five days to induce chronic HOS. sEVs were isolated using differential centrifugation followed by iodixanol density gradient flotation. Particle number was determined using Nanoparticle Tracking Analysis (NTA). Mass spectrometry was used to assess the sEV proteome, and selected proteins were validated by immunoblot. Proteome pathways were analyzed using KEGG and CORUM. ResultsPathway analysis revealed an increase in metabolic proteins and proteasome components in sEV cargo released from hTCEpi cells exposed to HOS. These proteins were increased more than fourfold in HOS-sEVs. Examination of proteins involved in the endosomal pathway and NTA further confirmed an increase in HOS-sEV release. ConclusionOur findings suggest a potential mechanism whereby corneal epithelial cells exposed to HOS retain proteins involved in maintaining tissue integrity, while simultaneously releasing unneeded proteins involved in cell metabolism. The presence of metabolic proteins in sEVs may serve as early indicators of dry eye disease.

Perfluorooctane sulfonic acid (PFOS), a per- and polyfluoroalkyl substance (PFAS), is a widespread persistent environmental pollutant that has been implicated in various human health conditions, including infertility and cancer. Here, we investigate the effects of acute exposure to PFOS on human fallopian tube epithelial (FNE) cells that are essential for fertility and increasingly recognized as the origin site for high-grade serous ovarian cancer. We show that acute PFOS exposure changes morphology, arrests proliferation, impairs adhesion, and compromises epithelial integrity of FNE cells. Using transcriptomic profiling of FNE cells exposed to PFOS, we found increased expression of genes associated with stress-response signal transduction, including KRAS, and decreased expression of genes related to cholesterol transport and lipid homeostasis. We show that inhibition of MEK/ERK or cholesterol supplementation rescued changes in cell morphology. Further, we performed membrane fluidity measurements of cells exposed to PFOS and found elevated membrane disorder and fluidity. Our results are consistent with a model in which PFOS perturbs plasma membrane, activates stress-response signaling pathways, and impairs epithelial cell function. These studies establish a framework for understanding the effects of PFAS on cell physiology.

ABSTRACT BACKGROUND: Recent studies consisting primarily of white participants have found lowered plasmalogen levels to be associated with lower cognitive function. We explore the association of blood plasmalogen levels with global cognition and brain imaging metrics in older African Americans. METHODS: Included in these cross-sectional analyses were participants in the Minority Aging Research Study (MARS) and the Rush Clinical Core without dementia, available serum lipid levels, and a concurrent cognitive function assessment. A plasmalogen biosynthesis value (PBV) was calculated for each participant utilizing five ratios of four key glycerophospholipids. A linear regression model of global cognition was constructed with PBV, adjusted for sex, age, education, total cholesterol, and body mass index. In participants with 3T MRI brain imaging, the association between PBV and white matter hyperintensities (WMH) was explored. RESULTS: Of the 298 participants, the mean age was 74.6 years, mean education was 15.6 years, and 84% were women. The median PBV was 0.42 (interquartile range: 0.22 to 1.14). A unit higher in PBV was suggestively associated with a 0.17 {beta}-unit higher cognitive z-score (SE =0.09, p = 0.06). In 254 participants with MRI data, an increase in log10 SD of PBV suggested the less white matter hyperintensities (estimate = -0.20, SE = 0.12, p = 0.08). DISCUSSION: In older African Americans, higher PBV was associated with higher level of global cognition, and potentially lower levels of brain white matter hyperintensities. Larger studies are needed in additional cohorts to determine if PBV is associated with annual rate of change in cognitive function.

Lipodystrophies are a group of disorders featuring reduced adipose tissue mass or function, which often leads to significant metabolic disease, reduced lifespan and impaired quality of life. Individuals with congenital generalised lipodystrophy (CGL) have severely reduced adipose tissue mass. The loss of healthy systemic lipid storage typically causes hepatic steatosis and lipoatrophic diabetes. In addition, adipocyte-secreted hormones including leptin and adiponectin are dramatically reduced. Leptin has critical roles regulating appetite and broader effects on lipid and glucose metabolism. Daily injection with recombinant leptin is currently the only specific, approved treatment for CGL. The consequences of adiponectin loss in these patients are not fully understood. Likewise, the potential therapeutic benefit of adiponectin delivery is unclear. Here we examine the effect of delivering leptin or adiponectin by adeno-associated virus (AAV) as potential gene therapy treatment for metabolic disease in CGL using a well-characterised murine model of the condition. AAV-mediated leptin delivery significantly improved hepatic steatosis and hyperinsulinemia. However, adiponectin delivery did not lead to any observed beneficial effects. This demonstrates the potential of gene therapy approaches for long-term delivery of leptin in individuals with lipodystrophy, without the need for continuous supply of perishable therapeutics and painful daily injections.