Search Results (186)

27-Hydroxycholesterol (27OHChol), a cholesterol metabolite, induces inflammatory responses in monocytic cells and promotes their differentiation into mature dendritic cells. Here, we examined whether inhibition of heat shock protein 90 (HSP90) modulates these responses. Treatment with ganetespib, a selective HSP90 inhibitor, significantly reduced chemokine CCL2 expression, lowering monocytic cell migration. It also suppressed matrix metalloproteinase-9 (MMP-9) expression and attenuated the lipopolysaccharide (LPS) response otherwise amplified by 27OHChol. Furthermore, ganetespib decreased mature dendritic cell markers (CD80, CD83, CD88) and restored endocytic activity, indicating a less activated state. These changes suggest that HSP90 regulates 27OHChol-induced pro-inflammatory activation via its client proteins. To explore this mechanism, we examined the phosphorylation status of signaling proteins. 27OHChol enhanced phosphorylation of Akt and its downstream targets, S6 and 4E-BP1 within the Akt/mTORC1 pathway. Ganetespib reduced total and phosphorylated Akt and 4E-BP1, and selectively inhibited S6 phosphorylation without altering total protein level. Collectively, these findings demonstrate that HSP90 inhibition by ganetespib mitigates 27OHChol-driven monocytic cell activation through suppression of the HSP90-Akt/mTORC1 axis. Targeting this pathway may provide a promising therapeutic strategy for metabolic inflammation associated with oxysterols. Full article

Objective: The classification of hereditary spastic paraplegia (HSP) is based on genetics, and the number of genetic loci continues to increase with new genetic descriptions. Additionally, the number of new variants in known mutations continues to increase. In this paper, we aim to report our experience with genetically confirmed HSPs. Methods: We retrospectively evaluated 10 consecutive children with genetically confirmed HSPs. Results: In this study, we identified six novel mutations, including spastic paraplegia 11 (SPG11), glucosylceramidase beta 2 (GBA2), chromosome 19 open reading frame 12 (C19orf12), 1 in each of the Cytochrome P450 family 7 subfamily B member 1 (CYP7B1) genes, and two different mutations in the intropomyosin-receptor kinase fused gene (TFG) gene. We also identified different clinical phenotypes associated with known mutations. Conclusions: Heterozygous mutations with GBA2 and SPG11 mutation-related HSP are reported for the first time, expanding the known inheritance patterns. We report a novel homozygous chromosome 19 open reading frame 12 (C19orf12) mutation resulting in iron accumulation in the brain, broadening the genetic variants and clinical findings. We determine the first Turkish patients with carnitine palmitoyltransferase IC (CPT1C) and TFG gene mutation-related pure HSP. A pure form of HSP with two novel TFG gene mutations is also identified for the first time. We report the first Turkish patient with kinase D-interacting substrate of 220 kDa (KIDINS220) gene, broadening the clinical spectrum of KIDINS220 variant-related disorders to encompass certain HSPs. Moreover, a novel variant in the oxysterol7-hydroxylase (CYP7B1) gene is reported, expanding the genetic variants and clinical findings relating to SPG5. Full article

Increased hepatic triacylglycerol (TG) storage in lipid droplets (LDs) is a hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). Human carboxylesterase 1 (CES1) regulates TG storage and secretion in hepatocytes, but the mechanism remains to be elucidated. We performed studies in rat hepatoma McArdle RH7777 cells stably transfected with CES1 cDNA and in Ces1d-deficient mice using a variety of biochemical, pharmacological and cell biology approaches including the assessment of gene expression, confocal immunofluorescence microscopy, lipid synthesis measurements and quantitative mass spectrometry. CES1-expressing cells accrued more TG compared to cells lacking CES1 when incubated with oleic acid. CES1 increased the expression of Srebf1c, Nr1h3 and Nr1h2 encoding transcription factors (SREBP1c and LXRα and LXRβ, respectively) that regulate the expression of lipogenic genes. Additionally, CES1 increased the expression of Acsl1 encoding an enzyme catalyzing fatty acid activation and the expression of Dgat1 and Dgat2 encoding enzymes catalyzing TG synthesis. Treatment of CES1-expressing cells with PPARγ antagonist (GW9662), LXR antagonist (GSK2033) or CYP27A1 inhibitor Felodipine prevented CES1-mediated fatty acid esterification into TG. Ces1d-deficient mice fed high-fat diet (HFD) presented with decreased expression of Nr1h3, Nr1h2, Srebf1c and reduced hepatic TG content. Felodipine and GSK2033 treatment eliminated the differential effects on TG concentration between wild-type and Ces1d-deficient hepatocytes. The results suggest that CES1/Ces1d activates PPARγ, LXR and SREBP1c pathways, thereby increasing TG synthesis and LD storage by augmenting fatty acid esterification. Full article

The function of pleckstrin homology (PH) domains is to recognize and bind to specific phosphoinositides in the membranes as part of diverse cellular signaling processes. The structure of some PH domains has been solved by X-ray crystallography, but structures of many PH domains remain to be elucidated. In green alga Chlamydomonas reinhardtii, none of the PH domains have been crystallized or characterized. The goal of our study was to model and characterize in detail the structures of all eleven of the PH domains identified in C. reinhardtii. Our computational strategy of integrating the information available on sequence, structure, and function with modeling and biophysical characterization has uncovered new biological predictions for these proteins. These predictions can be validated by future rationally designed experimental studies as an extension of this work. Our results suggest that nine of the eleven C. reinhardtii PH domains show the classical electrostatic polarization of PH domains with a positively charged binding pocket and negatively charged opposing end. Our docking results predict only two PH domains bind specifically to a particular phosphoinositide, while all the other nine PH domains may be able to bind various inositol phospholipids. The lack of preference for a specific phosphoinositide headgroup implies that the positive charge in the binding pocket of the PH domains may be crucial in driving the interaction with the negatively charged phosphoinositides in a non-specific or promiscuous manner. We identified putative homologs of Dynamin GTPase, calcium/calmodulin-dependent kinase, Arf GAP, Rhythm of Chloroplast 23 (ROC23), and oxysterol binding proteins in C. reinhardtii that contain PH domains. In addition, we identified two PH domain-containing proteins that may play a role in the mating process and others that may be important for signaling under phosphate deficiency. Full article

An oxysterol, 25-Hydroxycholesterol (25OHChol), is produced through cholesterol oxidation and is involved in various cellular processes, including apoptosis. However, the precise mechanisms underlying 25OHChol-induced apoptosis in neuroblastoma cells remain unclear. The aim of this study was to elucidate the detailed molecular mechanisms by which 25OHChol induces apoptosis in human neuroblastoma cells. This study explores the apoptotic effects of 25OHChol and the associated signaling pathways in BE(2)-C cells, a widely used human neuroblastoma cell model for neuronal differentiation and cancer research. To evaluate the cytotoxicity of 25OHChol, cell viability was assessed using the CCK-8 assay, which demonstrated a concentration-dependent decline, indicating a potential induction of cell death. Morphological changes characteristic of apoptosis, such as nuclear condensation and fragmentation, were confirmed via DAPI staining. Additionally, Annexin V/PI flow cytometry analysis revealed an increase in late apoptotic cell populations, further corroborating apoptosis induction. To investigate the molecular mechanisms, we analyzed the expression of Bcl-2 family proteins via Western blotting. The results showed an elevated Bax/Bcl-2 ratio, suggesting activation of the intrinsic mitochondrial apoptotic pathway. This was further supported by a reduction in mitochondrial membrane potential (MMP), as measured by flow cytometry. Increased caspase-9 and caspase-3/7 activity provided additional evidence for caspase-mediated apoptosis. Moreover, treatment with the pan-caspase inhibitor Z-VAD-FMK led to a dose-dependent increase in cell viability, confirming the essential role of caspases in 25OHChol-induced apoptosis. In conclusion, this study demonstrates that 25OHChol triggers apoptosis in BE(2)-C neuroblastoma cells through activation of the intrinsic mitochondrial apoptotic pathway. These findings provide new insights into the cytotoxic effects of 25OHChol and its potential role in neuroblastoma cell death. Full article

Background: Senescence, a state of permanent cell cycle arrest, is a complex cellular phenomenon closely affiliated with age-related diseases and pathological fibrosis. Cellular senescence is now recognized as a significant contributor to organ fibrosis, largely driven by transforming growth factor beta (TGF-β) signaling, such as in metabolic dysfunction-associated steatohepatitis (MASH), idiopathic pulmonary fibrosis (IPF), chronic kidney disease (CKD), and myocardial fibrosis, which can lead to heart failure, cystic fibrosis, and fibrosis in pancreatic tumors, to name a few. MASH is a progressive inflammatory and fibrotic liver condition that has reached pandemic proportions, now considered the largest non-viral contributor to the need for liver transplantation. Methods: We previously studied Oxy210, an anti-fibrotic and anti-inflammatory, orally bioavailable, oxysterol-based drug candidate for MASH, using APOE*3-Leiden.CETP mice, a humanized hyperlipidemic mouse model that closely recapitulates the hallmarks of human MASH. In this model, treatment of mice with Oxy210 for 16 weeks caused significant amelioration of the disease, evidenced by reduced hepatic inflammation, lipid deposition, and fibrosis, atherosclerosis and adipose tissue inflammation. Results: Here we demonstrate increased hepatic expression of senescence-associated genes and senescence-associated secretory phenotype (SASP), correlated with the expression of pro-fibrotic and pro-inflammatorygenes in these mice during the development of MASH that are significantly inhibited by Oxy210. Using the HepG2 human hepatocyte cell line, we demonstrate the induced expression of senescent-associated genes and SASP by TGF-β and inhibition by Oxy210. Conclusions: These findings further support the potential therapeutic effects of Oxy210 mediated in part through inhibition of senescence-driven hepatic fibrosis and inflammation in MASH and perhaps in other senescence-associated fibrotic diseases. Full article

Oxysterols such as 7-ketocholesterol (7KCh) contribute to the pathogenesis of autoimmune and chronic inflammatory diseases by inducing oxidative stress and promoting pro-inflammatory immune cell activation. Dendritic cells (DCs) play a central role in maintaining immune tolerance, and their dysregulation is a key driver of autoimmunity. Targeting DCs by using natural compounds offers a promising strategy to restore redox balance and suppress aberrant immune responses. This study investigated the immunomodulatory and antioxidant properties of Lupeol, a natural triterpenoid, in human monocyte-derived DCs exposed to 7KCh. Flow cytometry and cytokine profiling demonstrated that Lupeol preserved the immature, tolerogenic phenotype of DCs by promoting a dose-dependent increase in the anti-inflammatory cytokine IL-10. Lupeol also inhibited the 7KCh-induced upregulation of maturation markers (CD83, CD86) and suppressed the release of pro-inflammatory cytokines IL-1β and IL-12p70. Functionally, Lupeol-treated DCs directed T cell polarization toward an anti-inflammatory and regulatory profile while dampening the inflammatory responses triggered by 7KCh. This immunoregulatory effect was further supported by the decreased secretion of the pro-inflammatory cytokines IL-1β and IL-12p70 in DC culture supernatants. Mechanistic analyses using immunofluorescence showed that Lupeol alone significantly increased nuclear NRF2 levels and upregulated HO-1 expression. Western blot analysis further confirmed Lupeol’s ability to activate the KEAP1-NRF2 signaling pathway, as evidenced by increased expression of NRF2 and its downstream target, NQO1. The use of ML385, a selective NRF2 inhibitor, in ROS and cytokine assays supported the involvement of NRF2 in mediating the Lupeol antioxidant and anti-inflammatory effects in DCs. Notably, the oxidative burden induced by 7KCh limited the full activation of NRF2 signaling triggered by Lupeol. Furthermore, docking and MM/PBSA analyses revealed the specific interactions of Lupeol with the kelch domain of KEAP1. These findings suggest that Lupeol may serve as a promising orally available immunomodulatory agent capable of promoting tolerogenic DCs, offering potential applications in autoimmune and other chronic inflammatory diseases. Full article

Smith–Lemli–Opitz syndrome (SLOS) is a rare, autosomal recessive genetic disorder caused by mutations in the DHCR7 gene, which encodes the enzyme responsible for the final step in cholesterol biosynthesis. Impaired enzyme function leads to cholesterol deficiency, affecting the development and function of the entire organism. The accumulation of cholesterol precursors enhances the formation of oxysterols, which are involved in the pathomechanism of neurological, ophthalmological, and vascular changes in patients. This review analyzes 53 studies published between 2020 and 2025 on the molecular mechanisms underlying the clinical features of SLOS, including cholesterol deficiency, oxysterol accumulation, and the latest diagnostic methods, including LC-MS/MS chromatography and biomarkers such as GFAP for monitoring disease progression. MRI is discussed as a supportive tool for neuroimaging, along with advances in prenatal diagnostics, such as the detection of cholesterol precursors in neonatal hair. Therapeutic options are also reviewed, with particular emphasis on cholesterol supplementation, cholic acid, and experimental treatments such as vitamin E supplementation, statin therapy, gene therapy, and liver transplantation. Current research indicates that expanding knowledge in this area not only improves patient prognosis but also provides hope for the development of effective therapies in the future. Full article

Oxysterols can be derived from the diet, physiologically produced via specific enzymes, or are generated by autoxidation. These molecules have physiological properties and can also adversely affect vital organs. Indeed, some of them have pro-oxidant and pro-inflammatory activities and can lead to major pathologies. The present review focuses on oxysterols (7-ketocholesterol, 7β-hydroxycholesterol, 25-hydroxycholesterol, 27-hydroxycholesterol, 5,6α-epoxycholesterol, 5,6β-epoxycholesterol, and cholestane-3β, 5α, 6β-triol) involved either in cholesterol metabolism, age-related diseases (such as cardiovascular, neurodegenerative, and eye diseases, e.g., sarcopenia), and inflammatory diseases (especially Behcet’s disease and bowel and lung diseases (e.g., sarcoidosis, COVID-19)). Metabolic pathways associated with oxysterol-induced inflammation are discussed considering the cytokinic TLR4 pathway, non-cytokinic pathways, and the contribution of Ca²⁺ and K⁺ channels. Therapeutic approaches targeting oxysterol-induced inflammation either by natural or synthetic molecules are also presented. Full article

The pathogenesis of idiopathic pulmonary fibrosis (IPF) involves complex interactions between epithelial, mesenchymal, immune, and endothelial cells, often aggravated by lipid metabolism dysfunction, mitochondrial, and peroxisomal abnormalities. Changes in lipid metabolism may drive fibrotic processes, suggesting the potential of lipid biomarkers for disease monitoring. We compared here the cholesterol metabolism and very-long-chain fatty acid profiles of patients with IPF with healthy controls. The IPF patients’ lipidic profiles were also evaluated according to disease severity and progression rate. This prospective, observational study involved 50 IPF patients at disease diagnosis before antifibrotic treatment initiation and 50 age- and gender-matched healthy controls. Using a serum lipidomic profile, we focused on cholesterol synthesis, mitochondrial and peroxisomal markers, inflammatory lipids, and oxidative stress markers. Disease severity was evaluated using the Gender-Age-Physiology (GAP) index, while the prognosis was assessed by classifying patients as rapid or slow progressors based on a 24-month follow-up. IPF patients exhibited lower levels of cholesterol synthesis precursors (e.g., lathosterol), mitochondrial oxysterols, and inflammatory mediators (e.g., arachidonic acid) compared to controls. Reduced levels of these biomarkers were also associated with higher disease severity and rapid disease progression. Conversely, some peroxisomal markers (e.g., brassidic acid and nervonic acid) showed altered trends depending on disease severity. Our findings indicate that patients with IPF, compared to healthy controls, may show lipidomic alterations, particularly a reduction in cholesterol precursors and docosahexaenoic acids, which are also associated with IPF severity and progression. While preliminary, this study suggests lipidomics to be a promising tool to stratify IPF severity and prognosis. Full article

Hypercholesterolemia causes atherosclerosis by inducing immune cell migration and chronic inflammation in arterial walls. Recent single-cell analyses reveal the presence of lipid-enriched foamy macrophages, as well as other macrophage subtypes, neutrophils, T cells, and B cells, in atherosclerotic plaques in both animal models and humans. These cells interact with each other and other cells, including non-immune cells such as endothelial cells and smooth muscle cells. They thereby regulate metabolic, inflammatory, phagocytic, and cell death processes, thus affecting the progression and stability of atherosclerotic plaques. The nuclear receptors liver X receptor (LXR)α and LXRβ are transcription factors that are activated by oxysterols and regulate lipid metabolism and immune responses. LXRs regulate cholesterol homeostasis by controlling cholesterol’s transport, absorption, synthesis, and breakdown in the liver and intestine. LXRs are also highly expressed in tissue-resident and monocyte-derived macrophages and other immune cells, including both myeloid cells and lymphocytes, and they regulate both innate and adaptive immune responses. Interestingly, LXRs have immunosuppressive and immunoregulatory functions that are cell-type-dependent. In animal models of atherosclerosis, LXRs have been shown to be involved in both progression and regression phases. The pharmacological activation of LXR enhances cholesterol efflux from macrophages and promotes atherosclerosis progression. Deleting LXR in immune cells, especially myeloid cells, accelerates atherosclerosis by increasing monocyte migration, macrophage proliferation and activation, and neutrophil extracellular traps (NETs); furthermore, the deletion of hematopoietic LXRs impairs the regression of atherosclerotic plaques. Therefore, LXRs in immune cells may be a potent therapeutic target for atherosclerosis. Full article

Smith–Lemli–Opitz syndrome (SLOS) is a developmental disability arising from bi-allelic pathogenic variants in the 7-dehydrocholestrol reductase (DHCR7) enzyme and the accumulation of 7-dehydrocholesterol (7-DHC). 7-DHC spontaneously oxidizes and gives rise to cytotoxic oxysterols. Our recent high-throughput screening on Dhcr7-deficient Neuro2a cells identified hydroxyzine (HYZ) as a medication that could counteract the high levels of 7-DHC. We assessed the effects of HYZ in Dhcr7-deficient Neuro2a cells, neuronal cultures and glial cultures from Dhcr7^T93M/T93M transgenic mice, and human dermal fibroblasts from patients with SLOS. LC-MS/MS biochemical analyses revealed a strong modulatory effect of HYZ on post-lanosterol biosynthesis across all four SLOS models. However, the HYZ-induced biochemical changes were complex, dose-dependent, and variable across the four SLOS models. Dhcr7-deficient Neuro2a cells showed decreased 7-DHC, 8-dehydrocholesterol (8-DHC), and desmosterol (DES) levels (all p < 0.01), while neuronal and glial cultures from Dhcr7^T93M/T93M transgenic mice reported 8 significantly altered analytes (all p < 0.001). Human dermal fibroblast from patients with SLOS reacted to HYZ exposure with significantly decreased 7-DHC, 7-dehydrodesmosterol (7-DHD), and dihydrolanosterol (DHL) levels (p < 0.001), coupled with elevation in zymosterol (ZYM), zymostenol (ZYME), and 8-DHC (p < 0.001). Further evaluations are required to determine if the potentially beneficial effects of decreased 7-DHC, 7-DHD and DHL levels in SLOS models and patient biomaterials are counteracted by the rise in other post-lanosterol intermediates. Full article

Background/Objectives: Alterations of oxysterols and gut microbiota have been recognized as indicators affecting mild cognitive impairment (MCI) and sarcopenia, respectively, whereas their association with co-dysfunction has not been investigated. Methods: In this study, a total of 1035 individuals were divided into Control (n = 264), MCI (n = 435), and MCI with possible sarcopenia (MPS, n = 336) groups. Cognition and muscle indexes, serum oxysterols, and gut microbiota were measured. Spearman’s rank coefficients were calculated to determine their correlations. Results: Performances of global and multidimensional cognitive tests was successively worse in the Control, MCI, and MPS groups. Longer duration of five-time chair stand test, lower 6-meter walk speed, and handgrip strength were observed in the MPS group, along with increased 27-hydroxycholesterol (27-OHC) and 5α,6α-epoxycholesterol and decreased 5α-Cholest-8(14)-ene-3β,15α-diol (15-HC). Higher concentrations of amyloid precursor protein (APP), neurofilament, and C-terminal agrin fragment (CAF) were discovered in the MCI and MPS groups. The α-diversity of gut microbiota in the MCI and MPS group was remarkably decreased, followed by a shifted abundance of microbial taxa, such as Alistipes and Rikenellaceae. Multiple significant correlations were found between cognition and muscle indexes and with oxysterols. Conclusions: Our study indicates that oxysterols and gut microbiota are prominently involved in the co-dysfunction of cognition and muscle. Full article

This review summarizes the mechanisms and historical development of fungicides registered for grape downy mildew control in Japan, with a particular focus on their diverse molecular targets, including cell division and mitochondrial respiration. Grapevine downy mildew is one of the most important pathogens in Japanese grapevine cultivation. Grapevine downy mildew tends to be fungicide-resistant, and in recent years, a quinone outside inhibitor (QoI) fungicide-resistant strain of downy mildew has caused extensive damage in Yamanashi Prefecture, making headlines in newspapers. Although approximately 60 fungicides have been registered for downy mildew management in Japan, many have been withdrawn due to the emergence of resistant pathogen populations. Recent challenges with resistance to quinone outside inhibitors, carboxylic acid amides, and oxysterol-binding protein inhibitors underscore the ongoing importance of resistance management in Japanese viticulture and grape downy mildew control strategies. Full article

Wolman disease (WD) is a lethal disorder defined by the deficiency of the lysosomal acid lipase enzyme. Patients present with intestinal failure, malnutrition, and hepatosplenomegaly. Enzyme replacement therapy (ERT) with dietary substrate reduction (DSR) significantly improves survival. We sought to determine the outcomes of two siblings with WD treated after the onset of symptoms (sibling 1) and presymptomatic (sibling 2). A chart review was conducted on two siblings with WD treated with ERT and DSR at 4 months of age (sibling 1) and immediately after birth (sibling 2) to determine clinical outcomes based on survival, laboratory results, growth, dietary records, and gut biopsies. Sibling 1 presented with hepatosplenomegaly and liver dysfunction and developed hemophagocytic lymphohistiocytosis despite treatment. She received a bone marrow transplant at 8 months of age but died at 13 months. Sibling 2 is alive at 16 months of age with height, weight, and MUAC above the 95th centile, fully orally fed, with no gastrointestinal symptoms, normal liver function, and normal oxysterols. Sibling 2 duodenal biopsies show normal villus architecture with no foamy macrophage infiltration. Initiation of treatment prior to the onset of symptoms can prevent clinical manifestations and increase survival. The divergent trajectory in these siblings raises the question of WD’s candidacy for newborn screening. Full article