Transferrin Receptor Research Articles

Lowering the affinity of single-chain monovalent BBB shuttle scFc-scFv8D3 prolongs its half-life and increases brain concentration

Monoclonal antibody therapeutics is a massively growing field. Progress in providing monoclonal antibody therapeutics to treat brain disorders is complicated, due to the impermeability of the blood-brain barrier (BBB) to large macromolecular structures. To date, the most successful approach for delivering antibody therapeutics to the brain is by targeting the transferrin receptor (TfR) using anti-TfR BBB shuttles, with the 8D3 antibody being one of the most extensively studied in the field. The strategy of fine-tuning TfR binding affinity has shown promise, with previous results showing an improved brain delivery of bivalent 8D3-BBB constructs. In the current study, a fine-tuning TfR affinity strategy has been employed to improve single-chain variable fragment (scFv) 8D3 (scFv8D3) affinity mutants. Initially, in silico protein-protein docking analysis was performed to identify amino acids (AAs) likely to contribute to 8D3s TfR binding affinity. Mutating the identified AAs resulted in decreased TfR binding affinity, increased blood half-life and increased brain concentration. As monovalent BBB shuttles are seemingly superior for delivering antibodies at therapeutically relevant doses, our findings and approach may be relevant for optimizing brain delivery.

Interleukin 15-Presenting Nanovesicles with Doxorubicin-Loaded Ferritin Cores for Cancer Immunochemotherapy.

Interleukin 15 (IL15) is crucial for fostering the survival and proliferation of nature killer (NK) cells and cytotoxic T lymphocytes (CTLs), playing a pivotal role in tumor control. However, IL15 supplementary therapy encounters challenges such as systemic inflammation and non-specific stimulation of cancer cells. Herein, a nanovesicle termed DoxFILN, comprising a membrane presenting IL15/IL15 receptor α complexes (IL15c) and a core of doxorubicin-loaded ferritin (Dox-Fn) are reported. The DoxFILN significantly enhances the densities and activities of intratumoral CTLs and NK cells. Mechanistically, DoxFILN undergoes deshelling in the acidic tumor microenvironment, releasing Dox-Fn and membrane-bound IL15c. Dox-Fn selectively target transferrin receptors on cancerous cells, facilitating intracellular Dox release and inducing immunogenic cell death. Concurrently, membrane-bound IL15c recognizes and activates IL15 receptor β/γc heterodimers, leading to a remarkable increase in the proliferation and activation of CTLs (16-fold and 28-fold) and NK cells (37-fold and 50-fold). The IL15-displaying nanovesicle introduced here holds promise as a potential platform for immunochemotherapy in the treatment of cancer.

Determinants of Anemia in Schoolchildren in the Highland Bolivia

Anemia is a health problem of concern among schoolchildren in underprivileged rural regions, where recurrent parasitic infections are common. A cross-sectional study was conducted in 229 schoolchildren in rural highland Bolivia in the department of La Paz, an area with a high prevalence of protozoan and helminth infections, to determine the types and mechanisms of anemia. A substantial proportion of children (40.2%) were found to be anemic based on hemoglobin measurements. No associations were found between low hemoglobin levels and helminth or protozoan infections when evaluating infectious causes of anemia, nor with Giardia lamblia or Blastocystis hominis, which are associated with iron deficiency and nutrient malabsorption and were highly prevalent in this study. The significant association between anemia and hypochromia suggests iron deficiency, aligned with low hemoglobin levels. A total of 39 out of 150 children (26%) had markers consistent with iron deficiency anemia (IDA), 26 out of 127 children (20%) met the criteria for anemia of inflammation (AI). Furthermore, 12 of the 127 tested children (9.4%) met the criteria for mixed AI with IDA according to the soluble transferrin receptor (sTfR)/log ferritin levels, which increased significantly due to overall infections by Hymenolepis nana and Ascaris lumbricoides helminths. The findings highlight the need for integrated public health interventions to address iron nutrition and parasitic infections to effectively prevent anemia in this vulnerable population.

Biochanin A inhibits excitotoxicity-triggered ferroptosis in hippocampal neurons

Excitatory neurotransmitter-induced neuronal ferroptosis has been implicated in multiple neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Although there are several reports pertaining to the pharmacological activities of biochanin A, the effects of this isoflavone on excitotoxicity-triggered neuronal ferroptosis remain unclear. In this study, we demonstrate that biochanin A inhibits ferroptosis of mouse hippocampal neurons induced by glutamate or the glutamate analog, kainic acid. Biochanin A significantly inhibited accumulation of intracellular iron and lipid peroxidation in glutamate- or kainic acid-treated mouse hippocampal neurons. Furthermore, biochanin A regulated the level of glutathione peroxidase 4, a master regulator of ferroptosis, by modulating its autophagy-dependent degradation. We observed that biochanin A reduced the glutamate-induced accumulation of intracellular iron by regulating expression of iron metabolism-related proteins including ferroportin-1, divalent metal transferase 1, and transferrin receptor 1. Taken together, these results indicate that biochanin A effectively inhibits hippocampal neuronal death triggered by glutamate or kainic acid. Our study is the first to report that biochanin A has therapeutic potential for the treatment of diseases associated with hippocampal neuronal death, particularly ferroptosis induced by excitatory neurotransmitter.

Estudio prospectivo del síndrome de piernas inquietas en una muestra de donantes de sangre

Background and objectivesBlood donation is suggested to increase the risk of Restless Legs Syndrome (RLS). This study aims to assess the prevalence of RLS in Spanish blood donors and determined its potential correlation with iron metabolism parameters. Materials and methodsProspective cohort study of 129 blood donors (54.3% men, 39.44 years±11.0) that underwent a physical examination, blood analysis (hemoglobin, ferritin, transferrin saturation index and soluble transferrin receptor) and a RLS screening questionnaire followed by a prospective follow-up study including a clinical phone interview. A multivariate logistic regression model was performed to examine the association between RLS and other variables. ResultsEighty-four (65.1%) participants were repeat blood donors (mean of 2.11 donations/year) at inclusion and 61 (47.4%) at follow-up (mean of 2.09 donations/year). Non-anemic iron deficiency (ferritin<50μg /L) was high in women P<.001 and in repeat donors (P=.003). The prevalence of RLS was 14.1% at inclusion increasing prospectively (19.5%; P=.065). On multivariate analysis, gender was the only variable significantly associated with a RLS diagnosis, being higher in women (OR 5.1; 95% CI 1.71-15.3; P=.003). ConclusionsDespite the high prevalence of non-anemic iron deficiency there was no association between ferritin, soluble transferrin receptor concentration values and RLS diagnosis. Gender was associated with RLS diagnosis regardless of other variables.

Loss of calcium/calmodulin-dependent protein kinase kinase 2, transferrin, and transferrin receptor proteins in the temporal cortex of Alzheimer’s patients postmortem is associated with abnormal iron homeostasis: implications for patient survival

Loss of calcium/calmodulin-dependent protein kinase kinase 2, transferrin, and transferrin receptor proteins in the temporal cortex of Alzheimer’s patients postmortem is associated with abnormal iron homeostasis: implications for patient survival

Ferroptosis is involved in the damage of ocular lens under long-term PM2.5 exposure in rat models and humans

Epidemiological studies show a positive association between air pollution and age-related cataracts, but the pathogenic mechanism remains unclear. This study first demonstrates that fine particulate matter (PM2.5) induces ferroptosis in the lens, leading to morphological and functional disorders, through human, animal, and cellular samples. In 3-week PM2.5-exposed rat models (10 µl 1 mg/ml PM2.5 suspension per eye, 4 times a day), we find that many vacuoles form in the lens equatorial region by analysis of haematoxylin and eosin staining after PM2.5 exposure. Using iron and glutathione (GSH) assay kits, we found increased Fe2+ contents and decreased GSH levels in PM2.5-exposed rats’ lenses. Additionally, the lipid peroxide 4-hydroxynonenal (4-HNE) was also found to be elevated with immunoblot, suggesting ferroptosis is involved. Ferroptosis was also observed in human lens epithelial cells treated with 25, 50, and 100 µg/ml PM2.5 suspension for 24 h, accompanied by decreased cell viability and migration. Furthermore, we collect about 60 human lens anterior capsule (HLAC) samples for RNA-seq. The results show that compared to HLACs from areas with PM2.5 concentration ≤30 μg/m³, ferroptosis-related genes expression of those from areas with PM2.5 concentration ≥35 μg/m³ are significantly altered, such as glutathione peroxidase 4 and STEAP family member 3. Also, human lens in areas with high PM2.5 concentrations showed elevated levels of transferrin receptor and 4-HNE with immunoblot, and down-regulated expression of connexin 43 (Cx43) through immunofluorescent. These results demonstrate that ferroptosis plays a key role in PM2.5-induced cataractogenesis.

Effect of Transferrin-Modified Fe3O4 Nanoparticle Targeted Delivery miR-15a-5p Combined With Photothermal Therapy on Lung Cancer.

Existing studies have shown that transferrin receptor (TfR) is highly expressed on the surface of lung cancer cells, and nanoparticles (NPs) have been widely used as delivery vehicles. The aim of this study was to investigate the effect of the targeted delivery of Fe3O4 NPs modified with transferrin (Tf) compared with photothermal treatment for lung cancer. The morphology and properties of Fe3O4 NPs modified with Tf were tested by internal morphological characterization experiments including transmission electron microscopy, particle size meter infrared spectrometer and other experiments. The delivery of materials was investigated by cell proliferation and apoptosis experiments, and western blot experiment was used to detect yes-associated protein 1(YAP1) protein expression changes after delivering miR-15a-5p. In addition, animal models were constructed to further explore the targeting properties of the material. The results demonstrated that the nanomaterial has good stability and targeting properties. Meanwhile, we also discovered that the miR-15a-5p carried by NPs can inhibit cell growth after its entry to the lung cancer cells. The effect became more evident when the nanomaterials were assisted with laser therapy, as verified by invivo and invitro experiments. In terms of the related mechanism, miR-15a-5p inhibited YAP1 expression, which affected cell proliferation and apoptosis. In this study, Fe3O4 NPs modified with Tf delivered miR-15a-5p in combination with photothermal therapy for lung cancer. In future research, the targeted delivery of Tf and the photothermal synergy of nanomaterials will provide a theoretical basis for cancer treatment.

Increased Trypanocidal Activity of the Salinomycin Derivative Ironomycin Is Due to ROS Production and Iron Uptake Impairment

Salinomycin and its derivatives display promising anti-proliferating activity against bloodstream forms of Trypanosoma brucei. The mechanism of trypanocidal action of these compounds is due to their ionophoretic activity inducing an influx of sodium cations followed by osmotic water uptake, leading to massive swelling of bloodstream-form trypanosomes. Generally, higher trypanocidal activities of salinomycin derivatives are associated with higher cell swelling activities. Although ironomycin (C20-propargylamine derivative of salinomycin) and salinomycin showed identical cell swelling activities, ironomycin was 6 times more trypanocidal than salinomycin, and the 50% growth inhibition (GI50) values were 0.034 μM and 0.20 μM, respectively. However, when bloodstream-form trypanosomes were incubated with ironomycin in the presence of vitamin E and ammonium ferric citrate, the trypanocidal activity of the compound was reduced to that of salinomycin (GI50 = 0.21 μM vs. GI50 = 0.20 μM). In addition, vitamin E was found to decrease the trypanocidal activity of ironomycin much more than ammonium ferric citrate (GI50 = 0.18 μM vs. GI50 = 0.042 μM). Moreover, ironomycin caused a reduction in the uptake of the iron-carrier protein transferrin mediated by a downregulation of the transferrin receptor and led to the accumulation and sequestering of iron(II) in the parasite’s lysosome, triggering an increase production of reactive oxygen species (ROS). These results suggest that the increased trypanocidal activity of ironomycin can be mainly attributed to an increased ROS production and, to a lesser extent, an impairment in iron uptake.

Human Umbilical Cord Mesenchymal Stem Cells Alleviate Diabetic Nephropathy by Inhibiting Ferroptosis via the JNK/KEAP1/NRF2 Signaling Pathway.

Aims: Diabetic nephropathy (DN) is a major cause of end-stage renal disease, with no therapeutic interventions available to control its progression. Ferroptosis, an iron-dependent regulated cell death characterized by lipid peroxidation, plays a pivotal role in the pathogenesis of DN. Human umbilical cord mesenchymal stem cells (hUCMSCs) are an effective treatment modality for DN; however, the underlying mechanism of action remains unclear. The aim of the present study was to investigate whether hUCMSCs alleviate DN via inhibiting ferroptosis and its molecular mechanisms in type 2 diabetic mice and high-glucose and palmitate-stimulated human renal tubular epithelial cell (HK-11) models. Results: Our findings revealed that hUCMSCs improved the renal structure and function and tubular injuries. HUCMSC treatment can inhibit ferroptosis by decreasing iron content, reducing reactive oxygen species, malondialdehyde and 4-hydroxynonenal generation, decreasing the expression of positive ferroptosis mediator transferrin receptor 1 and long-chain acyl-CoA synthetase 4, and enhancing the expression of negative ferroptosis mediators (i.e., ferritin heavy chain, glutathione peroxidase 4, and system Xc-cystine/glutamate reverse transporter). Mechanistically, hUCMSC treatment inhibited c-Jun N-terminal kinase (JNK) and Kelch-like ECH-associated protein 1 (KEAP1) activation while increasing the expression of nuclear factor erythroid 2-related factor 2 (NRF2). Furthermore, pretreatment of HK-11 cells with NRF2 siRNA, the JNK inhibitor SP600125, or the JNK agonist anisomycin demonstrated the regulation of the JNK/KEAP1/NRF2 signaling pathway by hUCMSCs. Innovation and Conclusion: HUCMSCs inhibit ferroptosis in DN via the JNK/KEAP1/NRF2 signaling pathway, providing a new perspective and scientific evidence for treating DN. Antioxid. Redox Signal. 00, 000-000.

The PvRBP2b-TfR1 interaction is not essential for reticulocytes invasion by Plasmodium vivax isolates from Cambodia

Plasmodium vivax is the most widespread of the different Plasmodium species able to infect humans and is responsible for most malaria cases outside Africa. An effective, strain-transcending vaccine that alleviates or suppresses erythrocyte invasion would be a game-changer in eliminating vivax malaria. Recently, the binding of P. vivax Reticulocyte Binding Protein 2b (PvRBP2b) to human Transferrin receptor (TfR1) has been described as essential for reticulocyte invasion, making this parasite protein an appealing vaccine candidate. Here, using P. vivax Cambodian clinical isolates in robust ex vivo invasion assays, we show that anti-PvRBP2b polyclonal and monoclonal antibodies that inhibit binding of PvRBP2b to TfR1 do not block P. vivax invasion into reticulocytes even at high concentrations. Anti-TfR1 antibodies do not inhibit P. vivax invasion either. Combinations at high concentrations of human monoclonal antibodies targeting different PvRBP2b epitopes do not inhibit invasion. Combinations of anti-PvRBP2b with anti-PvDBP do not enhance invasion inhibition caused by anti-PvDBP alone. We also show that the invasion of Cambodian P. vivax is trypsin-resistant while TfR1 is trypsin-sensitive, and we demonstrate that TfR1 is not recycled following trypsin treatment. We determined the PvRBP2b sequence of all isolates used in the invasion assays and analyzed polymorphism within epitopes recognized by anti-PvRBP2b antibodies. We show that polymorphism does not explain the absence of neutralization. Anti-PvRBP2b polyclonal antibodies recognized all four isolates tested in immunofluorescence assays while not inhibiting P. vivax invasion. Overall, our results demonstrate that PvRBP2b binding to TfR1 is not essential for invasion into reticulocytes of P. vivax Cambodian strains questioning the relevance of PvRBP2b as vaccine candidate.

Targeting inhibition of T3JAM reduces brain cell ferroptosis in rat following ischemia/reperfusion via a mechanism involving prevention of TLR4-mediated iron overload

Iron overload-dependent ferroptosis is believed to contribute to the brain injury of ischemia/reperfusion (I/R), whereas toll-like receptor 4 (TLR4) can exert pro-ferroptosis effect via inhibiting the glutathione peroxidase 4 (GPX4) level, but the mechanisms behind these phenomenon are not fully elucidated. Tumor necrosis factor receptor correlated factor 3-interaction Jun amino-terminal kinase [JNK]-activating modulator (T3JAM) can activate specific molecule and its downstream signaling pathways, including TLR4. This study aims to explore whether targeting T3JAM can reduce I/R-induced ferroptosis in brain via downregulating TLR4. A Sprague Dawley (SD) rat model of cerebral I/R injury was established by 2 h-ischemia plus 24 h-reperfusion, which displayed brain injury (increases in neurological deficit score and infarct volume) and upregulation of T3JAM and TLR4, concomitant with the increased ferroptosis, reflected by increases in the levels of transferrin receptor protein 1 (TfR1), total iron, Fe2+ and lipid peroxidation (LPO) while decreases in the levels of ferroportin (FPN) and GPX4. Consistently, similar results were achieved in the cultured HT22 cells subjected to 8h-oxygen-glucose deprivation plus 12 h-reoxygenation (OGD/R), and knockdown of T3JAM reversed these phenomena. Moreover, Telaprevir, an anti-hepatitis C virus (HCV) drug, could also provide beneficial effect on alleviating ischemic brain injury via inhibition of T3JAM. Based on these observations, we conclud that inhibition of T3JAM can reduce I/R-induced brain cell ferroptosis through downregulating TLR4 and that T3JAM could be a potential target for identifying novel or existing drugs (such as Telaprevir) to treat cerebral I/R injury.

Increased Concentrations of Dopamine in the Blood and the State of the Immune System in Practically Healthy Residents of the Northern Territories

The numerous effects of dopamine are predetermined by the fact that it, being a chemical precursor of noradrenaline, is secreted in nervous tissue, in the adrenal medulla, kidneys, intestines, and APUD cells (Apudocytes). The purpose of the work is to study the effectiveness of immune reactions at elevated concentrations of dopamine in the blood of practically healthy residents of the northern territories. The results of an immunological examination of 1064 practically healthy people aged 25-55 years living in the Arkhangelsk and Murmansk regions, as well as in the Nenets Autonomous Okrug, the Komi Republic and the Svalbard archipelago (Barentsburg) were analyzed. It was found that elevated concentrations of dopamine in peripheral venous blood were more often recorded in Arctic residents; during the polar day, dopamine concentrations are higher than in winter. Increased concentrations of dopamine in the blood of Northerners are associated with a decrease in the level of activated T cells with the transferrin receptor and IL-2, T-helper cells, as well as with increased concentrations of IL-1β, TNF-α, cortisol and thyroxine. An increase in dopamine concentration may be a consequence of a cytokine reaction in the nervous tissue to inhibit excessive receptor activity of cells by increasing the concentration of IL-10. The formation of an excess of both central hormones secreted by the pituitary gland and peripheral hormones at the same time is probably due to an increase in the sensitivity threshold of the hypothalamus, which is associated with an increase in the flow of interoceptive impulses of afferent systems.

Association between trandsferrin receptor and urine cobalt: NHANES 2015-2020

Abstract. The transferrin receptor protein 1 (TfR1) is a critical cellular membrane protein. It orchestrates the internal transport and metabolism of iron, a vital process for intracellular functions. Additionally, TfR1 has the capacity to bind with metals beyond iron, including cobalt and manganese; however, the specific mechanisms of this binding and subsequent interactions with other proteins remain elusive. This study delves into the potential correlation between TfR1 levels in humans and the presence of cobalt in urine. Drawing on data from 3,424 participants across three survey cycles spanning two years each, this paper meticulously contrasts the clinical features of individuals across diverse TfR1 and urinary cobalt levels. Through the lens of both univariate and multivariate linear regression analyses, the research uncovers an inverse connection between TfR1 concentrations and urinary cobalt, post exclusion of participants with incomplete biochemical profiles. This inverse relationship could shed light on the complex interplay between TfR1 and metal ions within the body, providing a deeper understanding that may inform future studies and potential clinical applications. In the multivariate linear regression analysis, it is found that with the increasing of TFR1 quartiles, the proportion of obese participants (P&lt;0.01), high level blood manganese, high cobalt level in urine and blood (P&lt;0.01) increased gradually. This association remained significant in sensitivity analysis, while in the stratified analysis, above association was not significant in men with samples aged 65 and over. Transferrin receptor protein levels might be positively associated with urinary cobalt in the general U.S. crowd.

Dynamin independent endocytosis is an alternative cell entry mechanism for multiple animal viruses.

Mammalian receptor-mediated endocytosis (RME) often involves at least one of three isoforms of the large GTPase dynamin (Dyn). Dyn pinches-off vesicles at the plasma membrane and mediates uptake of many viruses, although some viruses directly penetrate the plasma membrane. RME is classically interrogated by genetic and pharmacological interference, but this has been hampered by undesired effects. Here we studied virus entry in conditional genetic knock-out (KO) mouse embryonic fibroblasts lacking expression of all three dynamin isoforms (Dyn-KO-MEFs). The small canine parvovirus known to use a single receptor, transferrin receptor, strictly depended on dynamin. Larger viruses or viruses known to use multiple receptors, including alphaviruses, influenza, vesicular stomatitis, bunya, adeno, vaccinia, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and rhinoviruses infected Dyn-KO-MEFs, albeit at higher dosage than wild-type MEFs. In absence of the transmembrane protease serine subtype 2 (TMPRSS2), which normally activates the SARS-CoV-2 spike protein for plasma membrane fusion, SARS-CoV-2 infected angiotensin-converting enzyme 2 (ACE2)-expressing MEFs predominantly through dynamin- and actin-dependent endocytosis. In presence of TMPRSS2 the ancestral Wuhan-strain bypassed both dynamin-dependent and -independent endocytosis, and was less sensitive to endosome maturation inhibitors than the Omicron B1 and XBB variants, supporting the notion that the Omicron variants do not efficiently use TMPRSS2. Collectively, our study suggests that dynamin function at endocytic pits can be essential for infection with single-receptor viruses, while it is not essential but increases uptake and infection efficiency of multi-receptor viruses that otherwise rely on a functional actin network for infection.

Regulatory Role of eIF2αK4 in Amino Acid Transporter Expression in Mouse Brain Capillary Endothelial Cells.

Amino acid transporters are expressed in the brain capillary endothelial cells that form the blood-brain barrier (BBB), and their expression levels change during the neonatal period. This study aimed to investigate the molecular mechanisms regulating amino acid transporter levels in mouse brain capillary endothelial cells. Capillaries were isolated from the brains of neonatal and adult mice. Activation of eukaryotic translation initiation factor 2α kinase 4 (eIF2αK4) was analyzed in MBEC4 (mouse brain capillary endothelial) cells under amino acid-depleted conditions. Protein expression was determined using western blotting and proteomic analyses. Phosphorylation of eIF2α, a downstream target of eIF2αK4, was induced in the brain capillaries of neonates compared to adults. In vitro experiments using MBEC4 cells revealed that amino acid depletion induced eIF2α phosphorylation and expression of the amino acid transporter, solute carrier (Slc)-7a1. The eIF2αK4 inhibitor, GCN2iB, inhibited these inductions. Proteomic analysis revealed arginine depletion-dependent induction of amino acid transporters Slc1a4, Slc3a2, Slc7a1, Slc7a5, and Slc38a1. These effects were also inhibited by GCN2iB, suggesting the involvement of eIF2αK4 activation. In contrast, the expression of Slc2a1, Slc16a1, Abcb1b, Abcg2, transferrin receptor, insulin receptor, claudin-1, ZO-1, and Jam1 was not suppressed by the GCN2iB treatment. Overall, the eIF2αK4 pathway plays a regulatory role in amino acid transporter expression in brain capillary endothelial cells and facilitates the maintenance of amino acid homeostasis in the brain. This study provides new insights into the regulatory mechanisms underlying nutrient transport across the BBB.

Detection of molecular markers of ferroptosis in human Alzheimer's disease brains.

We have previously shown that droplet degeneration (DD) signifies the beginning of neuritic plaque formation during Alzheimer's disease (AD) pathogenesis. As microglia associated with neuritic plaques exhibited strong ferritin expression and Perl's iron staining showed iron in microglia, droplet spheres and neuritic plaque cores, we hypothesized that DD is a form of ferroptosis. Detection of molecular markers of ferroptosis in AD brains. Immunohistochemical detection of transferrin receptor (TfR) and ferritin as ferroptosis markers in prefrontal cortex of AD brains, investigation of spatial correlation of these with histopathological hallmarks of AD, visualization of ferroptotic marker genes by in situ hybridization, comparison of expression of ferroptosis genes with snRNAseq analyses and comparison of TfR and ferritin expression in different neurofibrillary tangle (NFT) stages. TfR was found on neurons that appeared to be degenerating and exhibited typical features of droplet degeneration. Co-localization with hyperphosphorylated tau (p-tau) was a rare event. TfR-positive neurons increased with higher NFT stages as did ferritin expression in microglia. mRNA of genes linked to ferroptosis was detected in pretangles and p-tau negative neurons, less in DD. snRNAseq analyses support a link between AD, ferroptosis and TfR as a ferroptosis marker. Increased expression of TfR and ferritin in high NFT stages, demonstration of ferroptotic marker genes in Alzheimer's lesions, as well as snRNAseq analyses strengthen our hypothesis that DD represents ferroptosis. Because of the morphological similarity between TfR-positive structures and DD, TfR might be an early ferroptosis marker expressed transiently during AD pathogenesis.

SURG-58. COLD ATMOSPHERIC PLASMA (CAP) CAUSES SELECTIVE TUMOR CELL DEATH VIA APOPTOSIS AND FERROPTOSIS IN MALIGNANT GLIOMA CELLS

Abstract BACKGROUND High-grade gliomas (HGGs) are primary brain tumors associated with significant morbidity and mortality, and despite advances in neuro-oncology, the prognosis remains poor. Cold atmospheric plasma, a novel experimental anti-cancer therapeutic tool, is a near-room temperature ionized gas generated at atmospheric pressure. It has many promising results in vitro and in vivo with a variety of cancers. CAP cytotoxicity appears to be selective to cancer cells without significant damage to surrounding healthy tissues. We aim to evaluate the efficacy of CAP in generating tumor-selective cytotoxicity against high-grade glioma. METHODS B16, U87, GL261, patient derived high grade glioma, human neural stem cells (LM-NSC008) and astrocytes (NHA hTERT) were treated with CAP. Proliferation and propidium iodide (PI)/annexin V flow cytometry assays were employed to quantify cytotoxicity, cell cycle phases and apoptosis. Cells were pre-treated with ferroptosis inhibitors Ferrostatin-1 and Deferoxamine (DFO) in rescue assays. Cerebral organoids were transplanted with fluorescent tumor cell lines and stained with cleaved caspase-3, ki67 and transferrin receptor. RESULTS CAP induces dose dependent cell death in all glioma cell lines tested. CAP induces an accumulation of intracellular ROS, most prominent in glioma cells. CAP-mediated cell death involves apoptosis and ferroptosis. CAP selectively leads to apoptosis in tumor implanted organoids and leads to decreased proliferation in malignant and non-malignant cells. CAP leads to a shift into G0 phase of all treated cells, malignant and non-malignant. CONCLUSIONS CAP treatment induces dose-dependent increases in ROS and apoptosis in HGG lines tested more significantly than in NHAs and hNSCs. CAP induces decreased proliferation and G0 phase cell cycle arrest in all CAP-treated cells. CAP-mediated cytotoxicity was significantly mitigated with DFO pre-treatment in HGG cells, suggesting that ferroptosis plays a critical role in the mechanism of CAP treatment in HGG. CAP led to selective glioma cell death in tumor implanted cerebral organoids.

Alterations of Hepcidin and Iron Markers Associated with Obesity and Obesity-related Diabetes in Gambian Women

Aims Obesity, type 2 diabetes (T2D), and chronic inflammation are associated with disturbances in iron metabolism. Hepcidin is hypothesized to play a role in these alterations owing to its strong association with inflammation via the JAK-STAT3 pathway. The current study investigated the differences between inflammatory markers and iron indices and their association with hepcidin in lean women, women with obesity, and women with obesity and T2D (obesity-T2D) in The Gambia. Materials and methods In a cross-sectional study design, fasted blood samples were collected from three groups of women: lean women (n=42, body mass index (BMI)=20.9 kg/m2), women with obesity (n=48, BMI=33.1 kg/m2) and women with obesity-T2D (n=30, BMI=34.5 kg/m2). Markers of inflammation (IL-6 and CRP) and iron metabolism [hepcidin, iron, ferritin, soluble transferrin receptor (sTfR), transferrin, transferrin saturation, and unsaturated iron-binding capacity (UIBC)] were compared using linear regression models. Simple regression analyses were performed to assess the association between hepcidin levels and respective markers. Results Women with obesity and obesity-T2D showed elevated levels of inflammatory markers. There was no evidence that markers of iron metabolism differed between lean women and obese women, but women with obesity-T2D had higher transferrin saturation, higher serum iron concentration, and lower UIBC. Serum hepcidin concentrations were similar in all the groups. Hepcidin was not associated with markers of inflammation but was strongly associated with all other iron indices (all P&lt;0.002). Conclusion Contrary to our original hypothesis, hepcidin was not associated with markers of inflammation in the three groups of Gambian women, despite the presence of chronic inflammation in women with obesity and obesity-T2D.

Transcriptomic and de novo proteomic analyses of organotypic entorhino-hippocampal tissue cultures reveal changes in metabolic and signaling regulators in TTX-induced synaptic plasticity

Understanding the mechanisms of synaptic plasticity is crucial for elucidating how the brain adapts to internal and external stimuli. A key objective of plasticity is maintaining physiological activity states during perturbations by adjusting synaptic transmission through negative feedback mechanisms. However, identifying and characterizing novel molecular targets orchestrating synaptic plasticity remains a significant challenge. This study investigated the effects of tetrodotoxin (TTX)-induced synaptic plasticity within organotypic entorhino-hippocampal tissue cultures, offering insights into the functional, transcriptomic, and proteomic changes associated with network inhibition via voltage-gated sodium channel blockade. Our experiments demonstrate that TTX treatment induces substantial functional plasticity of excitatory synapses, as evidenced by increased miniature excitatory postsynaptic current (mEPSC) amplitudes and frequencies in both dentate granule cells and CA1 pyramidal neurons. Correlating transcriptomic and proteomic data, we identified novel targets for future research into homeostatic plasticity, including cytoglobin, SLIT-ROBO Rho GTPase Activating Protein 3, Transferrin receptor, and 3-Hydroxy-3-Methylglutaryl-CoA Synthase 1. These data provide a valuable resource for future studies aiming to understand the orchestration of homeostatic plasticity by metabolic pathways in distinct cell types of the central nervous system.