Modification of Nanoparticles with Transferrin for Targeting Brain Tissues

The delivery of therapeutics to brain tissues is one of the main challenges in neuropathology. For the past two decades, a variety of drug delivery systems has been designed to target components of the blood-brain barrier, including the transferrin receptor, a transmembrane glycoprotein highly expressed in the brain endothelium.In this protocol, we describe the use of transferrin protein to activate the surface of nanoparticles with the aim to direct their uptake in the brain. The molecule is bound by an amide linker to a PEGylated lipid commonly used in the preparation of lipid nanoparticles, micelles, and liposomes.

Selective transferrin coating as a facile strategy to fabricate BBB-permeable and targeted vesicles for potent RNAi therapy of brain metastatic breast cancer in vivo

Brain metastases are a most disturbing situation for breast cancer patients as there is basically no adequate treatment available. Any potential drug formulation has to be able to cross the blood-brain barrier (BBB) and specific to metastatic brain tumors without causing unacceptable adverse effects. Here, we developed transferrin-functionalized chimeric polymersomes carrying siRNA against polo-like kinase 1 (Tf@TBP-CPs-siPLK1) for treating brain metastatic MDA-MB 231 triple negative breast cancer (TNBC) xenografts in mice. To facilitate the loading of siPLK1, chimaeric polymersomes (CPs) were designed with spermine in the watery core and transferrin-binding peptide (TBP) at the surface, enabling attachment of transferrin after the siRNA loading step and thereby circumventing interference of transferrin with siRNA loading. Tf@TBP-CPs-siPLK1 encapsulating 3.8 wt% siRNA had a mean size of about 50 nm and a neutral zeta potential in phosphate buffer (PB). By virtue of the presence of transferrin, Tf@TBP-CPs demonstrated greatly (ca. 5-fold) enhanced internalization in MDA-MB 231 cells and transcytosis in the endothelial (bEnd.3) monolayer model in vitro as well as markedly improved accumulation in the orthotopically xenografted MDA-MB 231 tumor in the brain in vivo compared with control CPs lacking transferrin, supporting that transferrin mediates efficient BBB penetration and high specificity towards MDA-MB 231 cells. As a result, Tf@TBP-CPs-siPLK1 effectively inhibited tumor progression and prolonged the lifespan of the mice significantly. Selective transferrin coating appears to be a particularly facile strategy to fabricate BBB-permeable and targeted vesicles for potent RNAi therapy of brain metastatic breast cancer.

Low-molecular-weight chromium-binding substance (LMWCr) may bind and carry Cr(III) from the endosome

Trivalent chromium has been proposed to be transported in vivo from the bloodstream to the tissues via endocytosis by transferrin (Tf), the major iron transport protein in the blood. While Cr(III) loss from the Tf/Tf receptor complex after acidification to pH 5.5 has recently been shown to be sufficiently rapid to be physiologically relevant, the released Cr(III) still must exit the endosome during the time of the endocytosis cycle (circa 15 min). Cr(III) binds too slowly to small ligands such as citrate or ascorbate, or even EDTA, for such complexes to form and be transported from the endosome, while no trivalent ion transporters are known. However, the apo form of the peptide low-molecular-weight chromium-binding substance (LMWCr) can remove Cr(III) from Cr(III)₂-Tf at neutral pH, albeit slowly, and LMWCr is known to be transported from cells after binding Cr(III), although the transporter is not known. LMWCr subsequently carries Cr(III) to the bloodstream ultimately for removal from the body in the urine. The rate of binding of Cr(III) to apoLMWCr was significantly enhanced in the presence of the Tf/Tf receptor complex. These results suggest that apoLMWCr may function to bind Cr(III) released in the endosomes for ultimate removal from the body as part of a Cr(III) detoxification process.

Transferrin-based radiolabeled probe predicts the sensitivity of human renal cancer cell lines to ferroptosis inducer erastin

Ferroptosis induction has been recognized as a novel cancer therapeutic strategy. To effectively apply ferroptosis-targeting cancer therapy to individual patients, a diagnostic indicator for selecting this therapeutic strategy from a number of molecular targeting drugs is needed. However, to date, methods that can predict the efficacy of ferroptosis-targeting treatment have not been established yet. In this study, we focused on the iron metabolic pathway to develop a nuclear imaging technique for diagnosing the susceptibility of cancer cells to ferroptosis. As a nuclear probe, human transferrin (Tf) was labeled with Gallium-68 (68Ga) using 2-(p-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) as a chelator (68Ga-NOTA-Tf). Western blot assay and clonogenic survival assay with human renal cancer cell lines A498 and 786-O revealed that the protein expression level of transferrin receptor1 (TfR1) and sensitivity to a ferroptosis inducer, erastin, were correlated. A cellular uptake assay with 68Ga-NOTA-Tf revealed that the cancer cells sensitive to erastin highly internalized the 68Ga-NOTA-Tf. Furthermore, treatment with the TfR1 inhibitor ferristatin II reduced the cellular uptake of 68Ga-NOTA-Tf, indicating that the intracellular uptake of the probe was mediated by TfR1. These results suggest that 68Ga-NOTA-Tf can be useful in predicting the sensitivity of cancer cells to ferroptosis inducers.

Sex-related response in mice after sub-acute intraperitoneal exposure to silver nanoparticles

Silver nanoparticles (AgNPs) are among the most commercialized nanomaterials in biomedicine due to their antimicrobial and anti-inflammatory properties. Nevertheless, possible health hazards of exposure to AgNPs are yet to be understood and therefore raise public concern in regards of their safety. In this study, sex-related differences, role of steroidal hormones and influence of two different surface stabilizing agents (polymer vs. protein) on distribution and adverse effects of AgNPs were investigated in vivo. Intact and gonadectomised male and female mice were treated with seven AgNPs doses administered intraperitoneally during 21 days. After treatment, steroid hormone levels in serum, accumulation of Ag levels and oxidative stress biomarkers in liver, kidneys, brain and lungs were determined. Sex-related differences were observed in almost all tissues. Concentration of Ag was significantly higher in the liver of females compared to males. No significant difference was found for AgNP accumulation in lungs between females and males, while the lungs of intact males showed significantly higher Ag accumulation compared to gonadectomised group. Effect of surface coating was also observed, as Ag accumulation was significantly higher in kidneys and liver of intact females, as well as in kidneys and brain of intact males treated with protein-coated AgNPs compared to polymeric AgNPs. Oxidative stress response to AgNPs was the most pronounced in kidneys where protein-coated AgNPs induced stronger effects compared to polymeric AgNPs. Interestingly, protein-coated AgNPs reduced generation of reactive oxygen species in brains of females and gonadectomised males. Although there were no significant differences in levels of hormones in the AgNP-exposed animals compared to controls, sex-related differences in oxidative stress parameters were observed in all organs. Results of this study highlight the importance of including the sex-related differences and effects of protein corona in biosafety evaluation of AgNPs exposure.

Differences in growth of Trypanoplasma borreli in carp serum is dependent on transferrin genotype

Kinetoplastid parasites require transferrin (Tf), being the main source of iron, for growth and multiplication. This group of parasites developed a unique receptor-mediated system for acquiring host Tf which bears no structural homology with the host transferrin receptor. Trypanoplasma borreli, a blood parasite of common carp, probably uses a similar mechanism to sequester iron from host transferrin. In this study, we demonstrate a critical role of Tf for parasite growth. For in vitro studies we isolated and purified Tf from carp homozygous for the D or G allele of Tf. We obtained Tf-depleted serum using specific antibodies to carp Tf and studied gene expression in vivo during T. borreli infection with Real Time-quantitative PCR. We demonstrate that T. borreli cannot survive in medium supplemented with Tf-depleted serum while reconstitution with Tf restores normal growth. The critical role of Tf for parasite survival was shown in incomplete medium (medium without serum): addition of purified Tf significantly increased parasite survival. We also demonstrate that Tf polymorphism has a significant impact on T. borreli multiplication. Cultured parasites die more quickly in an environment containing D-typed Tf, as compared to medium with G-typed Tf. Gene expression during T. borreli infection in carp did not show an acute phase response. We could, however, observe an increased transcription of Tf in the head kidney, which may be associated with an immunological function of the Tf protein.

Investigating the interaction of CdTe quantum dots with plasma protein transferrin and their interacting consequences at the molecular and cellular level

This study investigated the interacting mechanism of CdTe quantum dots (QDs) with typical plasma protein transferrin (TF) as well as the impact of the formation of QDs-TF complex on the structure of TF and the cytotoxicity of mouse primary kidney cells. Dialysis experiments and cell viability assays revealed that the formation of QDs-TF complex reduced the contents of Cd released from CdTe QDs and thus counteracted the cytotoxicity of CdTe QDs. The assay of isothermal titration calorimetry found that CdTe QDs complexed with TF majorly through hydrophobic interaction. Multi-spectroscopic measurements showed that CdTe QDs caused the loosening of polypeptide chain, the changes of secondary and tertiary structures as well as the attenuated aggregation of TF molecule. Moreover, these structural and conformational changes were attributed to the nano-effects of CdTe QDs rather than the released Cd. This study is of great significance for fully evaluating the biocompatibility of Cd-QDs and comprehensively understanding the mechanism of Cd-QDs toxicity at the molecular and cellular level.

Heparin-decorated nanostructured lipid carriers of artemether-protoporphyrin IX-transferrin combination for therapy of malaria

Heme is a prosthetic group of hemoglobin comprising protoporphyrin IX (PPIX) with Fe²⁺. Studies have shown that modulating heme synthesis pathway in Plasmodium could greatly affect the action mechanism and antimalarial effect of artemisinin and its derivatives. Herein, an intraerythrocytic parasite targeted nanostructured lipid carrier (NLC) was developed for potentiation of artemether (ARM) by combination with PPIX and iron-loaded transferrin (holo-Tf). Firstly, ARM and PPIX were co-loaded into NLCs with high entrapment efficiency. Then, a targeting ligand heparin (HP) was electrostatically adsorbed onto the periphery of NLCs, followed by conjugation with holo-Tf to receive the final formulation Tf-HP-NLC/ARM/PPIX. Tf-HP-NLC/ARM/PPIX exhibited nanoscale particle size (~188 nm) and was relatively stable in simulated gastrointestinal fluids and rat plasma. A sustained drug release characteristic was observed in PBS (pH 7.4). In vitro targeting assay confirmed that Tf-HP-NLC/ARM/PPIX could be specifically and efficiently internalized into intraerythrocytic parasites via HP receptor-meditated endocytosis. Furthermore, due to enhanced intraparasitic accumulation and activated mechanism of ARM, the combinational delivery system Tf-HP-NLC/ARM/PPIX showed increased inhibitory activity against Plasmodium falciparum in culture and enhanced antimalarial effect in Plasmodium berghei-infected murine model, suggesting a promising strategy for development of new therapy based on action mechanism of ARM.

The comparison between light-scattering detectors based on LED and photodiode for immunoprecipitation assays of transferrin and ferritin

Undoubtedly, light-emitting diodes (LEDs) and photodiodes (PDs) are indispensable optoelectronic devices in modern analytical chemistry. LEDs can serve as either light emitters or detectors, thus being an alternative to the most popular detection systems consisted of PD. In this contribution, a comparison between LED-LED and LED-PD detectors, operating in turbidimetric and nephelometric modes, has been carried out for immunoprecipitation detection of transferrin and ferritin. The greatest emphasis was placed on the study of detectors responses under different measurement conditions including current powering an emitter, amplification gain in the case of PD as detector or the construction of detection cells designed for the Multicommutated Flow Analysis (MCFA). The assumption was to obtain the fully-mechanized system with simple but efficient detection system to enable the determination of iron-binding proteins occurring at different concentration ranges in human body. As a result, the optimized arrangements of LED-LED and LED-PD setups were characterized by similar analytical characteristics, enabling the determination of transferrin with the detection limit (LOD) of 0.2 mg/L and RSDs of 2.8-4.8% for LED-LED, and LOD of 0.1 mg/L and RSDs of 0.9-3.6% for LED-PD. In the case of ferritin detection, only the response of the LED-PD detector was statistically distinguishable in the range of 130-198 μg/L of protein with recorded analytical signal change of 20 mV value. The addition of polymer for signal enhancement provided the increase of response range to 107-253 μg/L, enabling the developed system for detection of pathological serum ferritin levels.

Iron-binding cellular profile of transferrin using label-free Raman hyperspectral imaging and singular value decomposition (SVD)

Serum transferrin (Tf) is the essential iron transport protein in the body. Transferrin is responsible for the sequestration of free iron in serum and the delivery of iron throughout the body and into cells, where iron is released inside a mildly acidified endosome. Altered iron distributions are associated with diseases such as iron-overload, cancer, and cardiovascular disease. The presence of free iron is linked to deleterious redox reactions, inside and outside cells and organelles. As Tf iron release is pH dependent, any changes in intraorganelle and extracellular pH, often associated with disease progression, could inhibit normal iron delivery or accelerate iron release in the wrong compartment. However, imaging approaches to monitor changes in the iron-bound state of Tf are lacking. Recently, Raman spectroscopy has been shown to measure iron-bound forms of Tf in solution, intact cells and tissue samples. Here, a biochemical Raman assay has been developed to identify iron-release from Tf following modification of chemical environment. Quantitative singular value decomposition (SVD) method has been applied to discriminate between iron-bound Tf samples during endocytic trafficking in intact cancer cells subjected to Raman hyperspectral confocal imaging. We demonstrate the strength of the SVD method to monitor pH-induced Tf iron-release using Raman hyperspectral imaging, providing the redox biology field with a novel tool that facilitates subcellular investigation of the iron-binding profile of transferrin in various disease models.

Alteration of iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn) tissue levels and speciation in rats with desferioxamine-induced iron deficiency

The objective of the present study was to investigate the impact of iron deficiency and iron replenishment on serum iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn) speciation and tissue accumulation in a deferrioxamine-induced model of iron deficiency. A total of 26 male Wistar rats were divided into three groups: control; Fe-deficient; Fe-replenished (with iron (II) gluconate). Serum ferritin and transferrin levels were assessed using immunoturbudimetric method. Liver, spleen, and serum metal levels were assessed using ICP-MS. Speciation analysis was performed using a hyphenated HPLC-ICP-MS technique. Desferrioxamine injections resulted in a significant decrease in tissue iron content that was reversed by Fe supplementation. Iron speciation revealed a significant increase in serum transferrin-bound iron and reduced ferritin-bound Fe levels. Serum but not tissue Cu levels were characterized by a significant decrease in hypoferremic rats, whereas ceruloplasmin-bound fraction tended to increase. At the same time, Zn levels were found to be higher in liver, spleen, and serum of Fe-deficient rats with a predominant increase in low molecular weight fraction.Both iron-deficient and iron-replenished rats were characteirzed by increased transferrin-bound Mn levels and reduced low-molecular weight fraction. Hypothetically, these differences may be associated with impaired Fe metabolism under Fe-deficient conditions predisposing to impairment of essential metal handling. However, further studies aimed at assessment of the impact on Fe deficiency on metal metabolism are highly required.

Multifunctional PLGA nanoparticles combining transferrin-targetability and pH-stimuli sensitivity enhanced doxorubicin intracellular delivery and in vitro antineoplastic activity in MDR tumor cells

Targeted delivery aims to enhance cellular uptake and improve therapeutic outcome with higher disease specificity. The expression of transferrin receptor (TfR) is upregulated on tumor cells, which make the protein Tf and its receptor vastly relevant when applied to targeting strategies. Here, we proposed Tf-decorated pH-sensitive PLGA nanoparticles containing the chemosensitizer poloxamer as a carrier for doxorubicin delivery to tumor cells (Tf-DOX-PLGA-NPs), aiming at alleviating multidrug resistance (MDR). We performed a range of in vitro studies to assess whether targeted NPs have the ability to improve DOX antitumor potential on resistant NCI/ADR-RES cells. All evaluations of the Tf-decorated NPs were performed comparatively to the nontargeted counterparts, aiming to evidence the real role of NP surface functionalization, along with the benefits of pH-sensitivity and poloxamer, in the improvement of antiproliferative activity and reversal of MDR. Tf-DOX-PLGA-NPs induced higher number of apoptotic events and ROS generation, along with cell cycle arrest. Moreover, they were efficiently internalized by NCI/ADR-RES cells, increasing DOX intracellular accumulation, which supports the greater cell killing ability of these targeted NPs with respect to MDR cells. Altogether, these findings supported the effectiveness of the Tf-surface modification of DOX-PLGA-NPs for an improved antiproliferative activity. Therefore, our pH-responsive Tf-inspired NPs are a promising smart drug delivery system to overcome MDR effect at some extent, enhancing the efficacy of DOX antitumor therapy.

Unmasking CSF protein corona: Effect on targeting capacity of nanoparticles

Among biological fluids, cerebrospinal fluid (CSF) not only protects and support brain, but also plays a pivotal role in intracerebral interaction of various nano-drug carriers. However, it is still uncertain how protein corona from CSF affects the targeting capability of functionalized nanoparticles (NPs). So, two types of polystyrene NPs, including PEGylated polystyrene NPs (PN) and transferrin (Tf)-modified PN (PT), were used to obtain protein corona-coated NPs, by incubating with CSF in vivo and in vitro. Strikingly, both the corona-coated NPs recovered in vivo and in vitro completely lost their active targeting characteristics towards bEnd.3 and C6 cells. Charge-, clathrin- and energy-mediated endocytosis contributed to the improved uptake efficiency of PT, whereas this enhancement in uptake of PT was disappeared after the formation of CSF protein corona. Moreover, serum albumin, which were found both in vivo and in vitro CSF corona, could mediate and facilitate the internalization of corona-coated NPs. Overall, these results have distinctly confirmed that the formation of CSF protein corona could cause the loss of active targeting specificity by shielding the targeting groups on the surface of polystyrene NPs and alter their cellular uptake by other non-specific internalization pathways.

Ligand decorated biodegradable nanomedicine in the treatment of cancer

Cancer is one of the major global health problems, responsible for the second-highest number of deaths. The genetic and epigenetic changes in the oncogenes or tumor suppressor genes alter the regulatory pathways leading to its onset and progression. Conventional methods are used in appropriate combinations for the treatment. Surgery effectively treats localized tumors; however, it fails to treat metastatic tumors, leading to a spread in other organs, causing a high recurrence rate and death. Among the different strategies, the nanocarriers-based approach is highly sought for, but its nonspecific delivery can cause a profound side effect on healthy cells. Targeted nanomedicine has the advantage of targeting cancer cells specifically by interacting with the receptors overexpressed on their surface, overcoming its non-specificity to target healthy cells. Nanocarriers prepared from biodegradable and biocompatible materials are decorated with different ligands by encapsulating therapeutic or diagnostic agents or both to target cancer cells overexpressing the receptors. Scientists are now utilizing a theranostic approach to simultaneously evaluate nanocarrier bio-distribution and its effect on the treatment regime. Herein, we have summarized the recent 5-year efforts in the development of the ligands decorated biodegradable nanocarriers, as a targeted nanomedicine approach, which has been highly promising in the treatment of cancer.

Serum ferritin levels in inflammation: a retrospective comparative analysis between COVID-19 and emergency surgical non-COVID-19 patients

BACKGROUND

SARS-CoV-2 infection has spread worldwide, and the pathogenic mechanism is still under investigation. The presence of a huge inflammatory response, defined as "cytokine storm," is being studied in order to understand what might be the prognostic factors implicated in the progression of the infection, with ferritin being one of such markers. The role of ferritin as a marker of inflammation is already known, and whether it changes differently between COVID and non-COVID patients still remains unclear. The aim of this retrospective analysis is to understand whether the inflammatory process in these two types is different.

METHODS

In this retrospective analysis, we compared 17 patients affected by SARS-CoV-2, who had been admitted between February and April 2020 (group A) along with 30 patients admitted for acute surgical disease with SARS-CoV-2 negative swab (group B). A further subgroup of Covid negative patients with leukocytosis was compared to group A.

RESULTS

In group A, the median (interquartile range) serum ferritin was 674 (1284) ng/mL, and it was double the cutoff (300 ng/mL) in 9 out of 17 (52%). The median (IQR) value of ferritin level in the total blood samples of group B was 231, and in the subgroup with leucocytosis, 149 (145). Group A showed a significantly higher ferritin median level compared to the entire group B (two-tailed Mann-Whitney test, p < 0.0001) as well as to the subgroup with leucocytosis (p < 0.0014).

CONCLUSIONS

The role of iron metabolism appears to be directly involved in COVID infection. On the other hand, in the acute inflammation of patients admitted for surgery, and probably in other common phlogistic processes, iron modifications appear to be self-limited. However, our finding suggests the use of ferritin as a marker for COVID infection.

Effects of albumin, transferrin and humic-like substances on iron-mediated OH radical formation in human lung fluids

Inhalation of particulate matter is hypothesized to contribute to health effects by overproducing reactive oxygen species (ROS) and inducing oxidative stress. Fe(II) has been shown to contribute to ROS generation in acellular simulated lung fluids. Atmospheric humic-like substances (HULIS) have been shown to chelate Fe(II) and significantly enhance this ROS generation. Here, we investigate Fe(II)-mediated ^.OH generation from the iron active proteins in lung fluid, albumin and transferrin, and fulvic acid, a surrogate for HULIS, in human bronchoalveolar lavage fluid (BALF). We find that albumin enhances ^.OH generation from inorganic Fe(II) and that transferrin attenuates this enhancement. We estimate the rate constants for albumin-Fe(II) and fulvic acid-Fe(II) mediated O₂^.- reduction (1.9 ± 0.3) M^-1 s^-1 and (2.7 ± 0.3) M^-1s^-1 (pH = 5.5, T = 37 °C), 17-25 times the rate for free iron, which we measured to be (110 ± 20) × 10^-3 M^-1s^-1, in agreement with the literature. ^.OH generation measured from fulvic acid-Fe(II) in BALF from 8 individuals with added fulvic acid is successfully predicted rates of ^.OH generation by mixtures of Fe(II), albumin, transferrin, fulvic acid, and ascorbate in saline solution. This indicates that fulvic acid enhances ^.OH formation in BALF, and that albumin and transferrin in BALF moderate the effect. We propose that fulvic acid, and thereby HULIS, is capable of mobilizing Fe(II) away from albumin and transferrin and this increases the formation rate of O₂^.- and ultimately of ^.OH. Furthermore, we find that albumin and transferrin have significantly different impacts on Fe(II)-mediated ^.OH than citrate, a common component of simulated lung fluids, a factor that should be considered carefully in the interpretation of results obtained from solutions containing citrate.

Bioconjugated solid lipid nanoparticles (SLNs) for targeted prostate cancer therapy

Prostate cancer is one of the prominent causes of cancer mortality in men all over the world and a challenge to treat. In this study, transferrin (Tf) bioconjugated solid lipid nanoparticles (SLNs) were developed and loaded with curcumin (CRC) for active targeting of prostate cancer cells. Curcumin is an anticancer agent, but its clinical applications are impeded due to the poor water solubility and bioavailability. Prepared blank Tf-SLNs showed minimal cytotoxicity while Tf-CRC-SLNs demonstrated significant in-vitro anti-proliferative activity compared to CRC-SLNs alone. Cellular uptake of Tf-CRC-SLNs were found to be significantly higher (p < 0.05/=0.01) compared to unconjugated SLNs or pure drug alone. Bioconjugated Tf-CRC-SLNs also showed improved early apoptotic and late apoptotic or early necrotic populations (6.4% and 88.9% respectively) to CRC-SLNs and CRC solution. Most importantly, in-vivo studies with Tf-CRC-SLNs in mice bearing prostate cancer revealed significant tumour regression (392.64 mm³ after 4 weeks, p < 0.001) compared to the control group. The findings of this work encourage future investigations and further in-vivo clinical studies on the potential of bioconjugated SLNs for cancer cure.

Effectiveness of porous silicon nanoparticle treatment at inhibiting the migration of a heterogeneous glioma cell population

BACKGROUND

Approximately 80% of brain tumours are gliomas. Despite treatment, patient mortality remains high due to local metastasis and relapse. It has been shown that transferrin-functionalised porous silicon nanoparticles (Tf@pSiNPs) can inhibit the migration of U87 glioma cells. However, the underlying mechanisms and the effect of glioma cell heterogeneity, which is a hallmark of the disease, on the efficacy of Tf@pSiNPs remains to be addressed.

RESULTS

Here, we observed that Tf@pSiNPs inhibited heterogeneous patient-derived glioma cells' (WK1) migration across small perforations (3 μm) by approximately 30%. A phenotypical characterisation of the migrated subpopulations revealed that the majority of them were nestin and fibroblast growth factor receptor 1 positive, an indication of their cancer stem cell origin. The treatment did not inhibit cell migration across large perforations (8 μm), nor cytoskeleton formation. This is in agreement with our previous observations that cellular-volume regulation is a mediator of Tf@pSiNPs' cell migration inhibition. Since aquaporin 9 (AQP9) is closely linked to cellular-volume regulation, and is highly expressed in glioma, the effect of AQP9 expression on WK1 migration was investigated. We showed that WK1 migration is correlated to the differential expression patterns of AQP9. However, AQP9-silencing did not affect WK1 cell migration across perforations, nor the efficacy of cell migration inhibition mediated by Tf@pSiNPs, suggesting that AQP9 is not a mediator of the inhibition.

CONCLUSION

This in vitro investigation highlights the unique therapeutic potentials of Tf@pSiNPs against glioma cell migration and indicates further optimisations that are required to maximise its therapeutic efficacies.

Spontaneous improvement of carbohydrate-deficient transferrin in PMM2-CDG without mannose observed in CDG natural history study

A recent report on long-term dietary mannose supplementation in phosphomannomutase 2 deficiency (PMM2-CDG) claimed improved glycosylation and called for double-blind randomized study of the dietary supplement in PMM2-CDG patients. A lack of efficacy of short-term mannose supplementation in multiple prior reports challenge this study’s conclusions. Additionally, some CDG types have previously been reported to demonstrate spontaneous improvement in glycosylated biomarkers, including transferrin. We have likewise observed improvements in transferrin glycosylation without mannose supplementation. This observation questions the reliability of transferrin as a therapeutic outcome measure in clinical trials for PMM2-CDG. We are concerned that renewed focus on mannose therapy in PMM2-CDG will detract from clinical trials of more promising therapies. Approaches to increase efficiency of clinical trials and ultimately improve patients’ lives requires prospective natural history studies and identification of reliable biomarkers linked to clinical outcomes in CDG. Collaborations with patients and families are essential to identifying meaningful study outcomes.

Serum transferrin as a biomarker of hepatocyte nuclear factor 4 alpha activity and hepatocyte function in liver diseases

BACKGROUND

Serum transferrin levels represent an independent predictor of mortality in patients with liver failure. Hepatocyte nuclear factor 4 alpha (HNF4α) is a master regulator of hepatocyte functions. The aim of this study was to explore whether serum transferrin reflects HNF4α activity.

METHODS

Factors regulating transferrin expression in alcoholic hepatitis (AH) were assessed via transcriptomic/methylomic analysis as well as chromatin immunoprecipitation coupled to DNA sequencing. The findings were corroborated in primary hepatocytes. Serum and liver samples from 40 patients with advanced liver disease of multiple etiologies were also studied.

RESULTS

In patients with advanced liver disease, serum transferrin levels correlated with hepatic transferrin expression (r = 0.51, p = 0.01). Immunohistochemical and biochemical tests confirmed reduced HNF4α and transferrin protein levels in individuals with cirrhosis. In AH, hepatic gene-gene correlation analysis in liver transcriptome revealed an enrichment of HNF4α signature in transferrin-correlated transcriptome while transforming growth factor beta 1 (TGFβ1), tumor necrosis factor α (TNFα), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6) negatively associated with transferrin signature. A key regulatory region in transferrin promoter was hypermethylated in patients with AH. In primary hepatocytes, treatment with TGFβ1 or the HNF4α inhibitor BI6015 suppressed transferrin production, while exposure to TNFα, IL-1β, and IL-6 had no effect. The correlation between hepatic HNF4A and transferrin mRNA levels was also seen in advanced liver disease.

CONCLUSIONS

Serum transferrin levels constitute a prognostic and mechanistic biomarker. Consequently, they may serve as a surrogate of impaired hepatic HNF4α signaling and liver failure.

Iron status in mid-pregnancy and associations with interpregnancy interval, hormonal contraceptives, dietary factors and supplement use

Adequate iron supply in pregnancy is important for both the woman and the fetus, but iron status is often assessed late in first trimester, if assessed at all. Therefore, identification of factors associated with iron status is important to target vulnerable groups with increased risk of deficiency. Our objectives were to (1) describe iron status in mid-pregnancy and (2) identify sociodemographic and lifestyle predictors of pregnancy iron status. This cross-sectional study uses data from The Norwegian Mother, Father and Child Cohort Study (collected 2002-2008) and The Medical Birth Registry of Norway. Iron status was measured as non-fasting plasma ferritin (P-Fe) and transferrin in gestational week (GW) 18 (n 2990), and by lowest reported Hb in GW 0-30 (n 39 322). We explored predictors of iron status with elastic net, linear and log-binomial regression models. Median P-Fe was 33 μg/l, and 14 % had depleted iron stores (P-Fe <15 μg/l). P-Fe below 30 μg/l was associated with reduced Hb. We identified eleven predictors, with interpregnancy interval (IPI) and parity among the most important. Depleted iron stores was more common among women with IPI < 6 months (56 %) and 6-11 months (33 %) than among those with IPI 24-59 months (19 %) and among nulliparous women (5 %). Positively associated factors with iron status included hormonal contraceptives, age, BMI, smoking, meat consumption and multi-supplement use. Our results highlight the importance of ferritin measurements in women of childbearing age, especially among women not using hormonal contraceptives and women with previous and recent childbirths.

Protein liposomes-mediated targeted acetylcholinesterase gene delivery for effective liver cancer therapy

BACKGROUND

Effective methods to deliver therapeutic genes to solid tumors and improve their bioavailability are the main challenges of current medical research on gene therapy. The development of efficient non-viral gene vector with tumor-targeting has very important application value in the field of cancer therapy. Proteolipid integrated with tumor-targeting potential of functional protein and excellent gene delivery performance has shown potential for targeted gene therapy.

RESULTS

Herein, we prepared transferrin-modified liposomes (Tf-PL) for the targeted delivery of acetylcholinesterase (AChE) therapeutic gene to liver cancer. We found that the derived Tf-PL/AChE liposomes exhibited much higher transfection efficiency than the commercial product Lipo 2000 and shown premium targeting efficacy to liver cancer SMMC-7721 cells in vitro. In vivo, the Tf-PL/AChE could effectively target liver cancer, and significantly inhibit the growth of liver cancer xenografts grafted in nude mice by subcutaneous administration.

CONCLUSIONS

This study proposed a transferrin-modified proteolipid-mediated gene delivery strategy for targeted liver cancer treatment, which has a promising potential for precise personalized cancer therapy.

Analysis of protein denaturation, aggregation and post-translational modification by agarose native gel electrophoresis

Agarose native gel electrophoresis has been developed to separate proteins and protein complexes in the native state. Here, we applied this technology to analyze proteins that undergo degradation, post-translational modification or chemical/physical changes. Antibodies showed aggregation/association upon acid or heat treatment. Limited reduction of disulfide bonds resulted in non-covalent aggregation of bovine serum albumin and cleavage of only inter-chain linkages of an antibody that had no effects on its overall structure. Native agarose gel analysis showed changes in mobility of human transferrin upon Fe³⁺ binding. Analysis of a commercial glycated human hemoglobin A1c showed no difference in electrophoretic pattern from un-modified hemoglobin. Native agarose gel showed aggregation of a virus upon acid or heat treatment. We have extracted bands of bovine serum albumin from the agarose native gel for sodium dodecylsulfate gel electrophoresis analysis, showing degradation of aged sample. Lastly, we analyzed phosphorylation of Zap70 kinase by native gel and Western blotting. These applications should expand the utility of this native gel electrophoresis technology.

The role of transferrins and iron-related proteins in brain iron transport: applications to neurological diseases

Iron transport in the central nervous system (CNS) is a highly regulated process in which several important proteins participate to ensure this important metal reaches its sites of action. However, iron accumulation has been shown to be a common factor in different neurological disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Multiple Sclerosis, and Sanfilippo syndrome. This review is divided into four parts. The first part describes brain iron transport in homeostasis, mentioning the main proteins involved, whereas the second part contrasts the consequences of iron dysregulation, elaborating on its role in the aforementioned neurodegenerative diseases. The third part details the functions of the main proteins involved in brain iron homeostasis and their role in neurodegeneration. In the fourth part, in order to highlight the importance of transport proteins, the focus is set on human serum transferrin, the main iron transport protein. This final part describes perspectives about the mechanisms and chemical properties of human transferrin for the development of potential targeted drug delivery systems across the blood-brain barrier (BBB) or enhancers for the treatment of neurological diseases.

Transferrin and antioxidants partly prevented mouse oocyte oxidative damage induced by exposure of cumulus-oocyte complexes to endometrioma fluid

Background

Exposure of oocytes to the endometrioma fluid has an adverse effect on embryonic quality. To determine whether adding transferrin and antioxidants to culture medium could counteract detrimental effects on mouse cumulus-oocyte complexes (COCs) induced by exposure to endometrioma fluid or not, we conducted an in vitro cross-sectional study using human and mouse COCs.

Methods

Eighteen women who had their oocytes exposed to endometrioma fluid during oocyte retrieval were enrolled. COCs from superovulated ICR female mice were collected. They were first exposed to human endometrioma fluid and then treated by transferrin and/or antioxidants (cysteamine + cystine). Subsequently, COCs function was assessed by molecular methods.

Results

This study observed that human COCs inadvertently exposed to endometrioma fluid in the in vitro fertilization (IVF) group led to a lower good quality embryo rate compared to intracytoplasmic sperm injection (ICSI) group. Exposure of mouse COCs to endometrioma fluid accelerated oocyte oxidative damage, evidenced by significantly reduced CCs viability, defective mitochondrial function, decreased GSH content and increased ROS level, associated with the significantly higher pro-portion of abnormal spindles and lower blastocyst formation (p < 0.05, respectively). This damage could be recovered partly by treating COCs with transferrin and antioxidants (cysteamine + cystine).

Conclusions

Transferrin and antioxidants could reduce the oxidative damage caused by COCs exposure to endometrioma fluid. This finding provides a promising new possibility for intervention in the human oocyte oxidative damage process induced by endometrioma fluid during oocyte pick-up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-020-00738-0.