23 research outputs found
Multidrug resistance P-glycoprotein dampens SR-BI cholesteryl ester uptake from high density lipoproteins in human leukemia cells
No full textTumor cells are characterised by a high content of cholesterol esters (CEs), while tumor-bearing patients show low levels of high-density lipoproteins (HDLs). The origin and significance of high CE levels in cancer cell biology has not been completely clarified. Recent evidence that lymphoblastic cells selectively acquire exogenous CE from HDL via the scavenger receptor SR-BI has drawn attention to the additional membrane proteins involved in this pathway. P-glycopotein-MDR1 (P-gp) is a product of the MDR1 gene and confers resistance to antitumor drugs. Its possible role in plasma membrane cholesterol trafficking and CE metabolism has been suggested. In the present study this aspect was investigated in a lymphoblastic cell line selected for MDR1 resistance. CEM were made resistant by stepwise exposure to low (LR) and high (HR) doses of vincristine (VCR). P-gp activity (3H-vinblastine), CE content, CE and triglycerides (TG) synthesis (14C-oleate), neutral lipids and Dil-HDL uptake (fluorescence), SR-BI, ABCA1 and P-gp protein expression (western blotting) were determined. To better evaluate the relationship between CE metabolism and P-gp activity, the ACAT inhibitor Sandoz-58035 and the P-gp inhibitors progesterone, cyclosporine and verapamil were used. CE content and synthesis were similar in the parental and resistant cells. However, in the latter population, SR-BI protein expression increased, whereas CE-HDL uptake decreased. These changes correlated with the degree of VCR-resistance. As well as reverting MDR1-resistance, the inhibitors of P-gp activity induced the CE-HDL/SR-BI pathway by reactivating membrane cholesterol trafficking. Indeed, CE-HDL uptake, SRBI expression and CE content increased, whereas there was a decrease in cholesterol esterification. These results demonstrated that P-gp overexpression impairs anticancer drug uptake as well as the SR-BI mediated selective CE-HDL uptake. This suggests that these membrane proteins act in an opposite manner on the same transport mechanism. Therefore, the dampening activity of P-gp in this pathway and its reversal by P-gp inhibitors open new strategies for antitumor therapy in drug-resistant tumors
The first days of life: incidence of the commensal-turned pathogen Fusobacterium nucleatum and VSCs in oral cavity of mothers and newborns.
No full textAims:
The aim of this study was to investigate the presence of different anaerobic periodontal bacteria in the tongue surface of the mothers and the new-borns from 0 to 48 months of birth. In addition, in these subjects, we have also monitored the volatile sulphur compounds: H2S, CH3S, (CH3)2S to investigate the tongue protease activity, especially in the first days of life.
Methods:
Fifty new-borns and forty mothers (from 22 to 48 years, mean 37) were recruited in this study. For each subject we have analysed: (i) the VSCs profile in the breath by OralChromaTM instrument, (ii) the amount of five periodontal pathogens in the tongue swab’s DNA: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia and Fusobacterium nucleatum, by using real time PCR procedure.
Results
75% of the mothers showed, in the breath, physiological levels of VSCs, while 15% presented a stable high amount of H2S (> 112 ppb). Instead, in all observed new-borns the results suggest a progressive production of oral H2S correlated with the months of life; this was also statistically associated with a significant progressive enrichment in the tongue of the anaerobic bacterium F. nucleatum, in addition we have observed that 92,5 % of mothers resulted positive for this microorganism.
Conclusions
The increase of H2S production and F. nucleatum, age dependent in all children, suggests a physiological role of this bacterium in oral cavity already in the first days of life. Following the experimental hypothesis of Starkenmann and collaborators, this microorganism could be useful in the tongue biofilm for modulating the smell/taste. In this context, the mothers could have a crucial position in this process, transmitting this anaerobic bacterium by saliva to oral cavity of the newborn.
Starkenmann et al., J Agric Food Chem. 2008:9575-80
Chronic hyperplastic anemia as an independent risk factor for atherosclerotic lesions: a lesson from thalassemia intermedia
No full textHigh-density lipoprotein contribute to G0-G1/S transition in Swiss NIH/3T3 fibroblasts
No full textHigh density lipoproteins (HDLs) play a crucial role in removing excess cholesterol from peripheral tissues. Although their concentration is lower during conditions of high cell growth rate (cancer and infections), their involvement during cell proliferation is not known. To this aim, we investigated the replicative cycles in synchronized Swiss 3T3 fibroblasts in different experimental conditions: i)
contact-inhibited fibroblasts re-entering cell cycle after dilution; ii) scratch-wound assay; iii) serum deprived cells induced to re-enter G1 by FCS, HDL or PDGF. Analyses were performed during each cell cycle up to quiescence. Cholesterol synthesis increased remarkably during the replicative cycles, decreasing only after cells reached confluence. In contrast, cholesteryl ester (CE) synthesis and
content were high at 24h after dilution and then decreased steeply in the successive cycles. Flow cytometry analysis of DiO-HDL, as well as radiolabeled HDL pulse, demonstrated a significant uptake of CE-HDL in 24h. DiI-HDL uptake, lipid droplets (LDs) and SR-BI immunostaining and expression followed the same trend. Addition of HDL or PDGF partially restore the proliferation rate and significantly increase SR-BI and pAKT expression in serum-deprived cells. In conclusion, cell transition from G0 to G1/S requires CE-HDL uptake, leading to CE-HDL/SR-BI pathway activation
and CEs increase into LDs
A large-scale screening identified in USH2A gene the P3272L founder pathogenic variant explaining familial Usher syndrome in Sardinia, Italy
No full textAbstract Background Usher syndrome (USH) encompasses a group of disorders characterized by congenital sensorineural hearing loss (SNHL) and retinitis pigmentosa (RP). We described the clinical findings, natural history, and molecular analyses of USH patients identified during a large-scale screening to identify quantitative traits related to ocular disorders in the SardiNIA project cohort. Methods We identified 3 USH-affected families out of a cohort of 6,148 healthy subjects. 9 subjects presented a pathological phenotype, with SNHL and RP. All patients and their family members underwent a complete ophthalmic examination including best-corrected visual acuity, slit-lamp biomicroscopy, fundoscopy, fundus autofluorescence, spectral-domain optical coherence tomography, and electrophysiological testing. Audiological evaluation was performed with a clinical audiometer. Genotyping was performed using several arrays integrated with whole genome sequence data providing approximately 22 million markers equally distributed for each subject analyzed. Molecular diagnostics focused on analysis of the following candidate genes: MYO7A, USH1C, CDH23, PCDH15, USH1G, CIB2, USH2A, GPR98, DFNB31, CLRN1, and PDZD7. Results A single missense causal variant in USH2A gene was identified in homozygous status in all patients and in heterozygous status in unaffected parents. The presence of multiple homozygous patients with the same phenotypic severity of the syndromic form suggests that the Sardinian USH phenotype is the result of a founder effect on a specific pathogenic variant related haplotype. The frequency of heterozygotes in general Sardinian population is 1.89. Additionally, to provide new insights into the structure of usherin and the pathological mechanisms caused by small pathogenic in-frame variants, like p.Pro3272Leu, molecular dynamics simulations of native and mutant protein–protein and protein–ligand complexes were performed that predicted a destabilization of the protein with a decrease in the free energy change. Conclusions Our results suggest that our approach is effective for the genetic diagnosis of USH. Based on the heterozygous frequency, targeted screening of this variant in the general population and in families at risk or with familial USH can be suggested. This can lead to more accurate molecular diagnosis, better genetic counseling, and improved molecular epidemiology data that are critical for future intervention plans. Trial registration We did not perform any health-related interventions for the participants
Assessing the Predictive Power of the Hemoglobin/Red Cell Distribution Width Ratio in Cancer: A Systematic Review and Future Directions
No full textBackground and Objectives: The hemoglobin (Hb)/red cell distribution width (RDW) ratio has emerged as an accessible, repeatable, and inexpensive prognostic factor that may predict survival in cancer patients. The focus of this systematic review is to investigate the prognostic role of the Hb/RDW ratio in cancer and the implications for clinical practice. Materials and Methods: A literature search of PubMed, Scopus, and Web of Science databases was performed by an independent author between 18 March and 30 March 2023 to collect relevant literature that assessed the prognostic value of the Hb/RDW ratio in cancer. Overall survival (OS), progression-free survival (PFS), and the association of these with the Hb/RDW ratio were considered to be the main endpoints. Results: Thirteen retrospective studies, including 3818 cancer patients, were identified and involved in this review. It was observed that, when patients with a high vs. low Hb/RDW ratio were compared, those with a lower Hb/RDW ratio had significantly poorer outcomes (p < 0.05). In lung cancer patients, a one-unit increase in the Hb/RDW ratio reduces mortality by 1.6 times, whilst in esophageal squamous-cell carcinoma patients, a lower Hb/RDW ratio results in a 1.416-times greater risk of mortality. Conclusions: A low Hb/RDW ratio was associated with poor OS and disease progression in patients with cancer. This blood parameter should be considered a standard biomarker in clinical practice for predicting OS and PFS in cancer patients. Future searches will be necessary to determine and standardize the Hb/RDW cut-off value and to assess whether the Hb/RDW ratio is optimal as an independent prognostic factor or if it requires incorporation into risk assessment models for predicting outcomes in cancer patients
A case of stroke as a unique sign of subclinical infective endocarditis by Abiotrophia defectiva: a case report
No full textPurpose: Here we describe a patient admitted for a stroke that was unexpectedly correlated with subclinical infective endocarditis attributable to a rarely opportunistic pathogen, Abiotrophia defectiva. Case report: A 75-year-old man presented with a stroke. Transesophageal echocardiography suggested vegetation on all aortic valve cusps, despite the absence of clinical or laboratory signs of infection. Surprisingly, three sets of blood cultures collected without fever were positive for A. defectiva. Although the patient did not exhibit classic signs of infection during hospitalization, the severity of the valve condition necessitated replacement with a bioprosthesis. Conclusions: This clinical case underscores the importance of investigating the infective origin of endocarditis, even in the absence of clinical or laboratory evidence. Physicians should maintain a high level of suspicion, especially in patients with highly suggestive anamnestic characteristics
The MBRD Dipoles for the Luminosity Upgrade at the LHC: From Prototype Tests to the Series Production
No full textThe recombination dipoles MBRD for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN are double-aperture superconducting magnets generating a central magnetic field of 4.5 T in a 105 mm diameter bore, directed in the same direction in both apertures. The integrated magnetic field is 35 T-m in a magnetic length of 7.78 m: with respect to the corresponding magnet presently installed in LHC, the aperture is larger, the length is smaller and the central field is higher. The project, currently underway, includes the fabrication by ASG Superconductors and testing at CERN of a short model (1.6 m long), a prototype, and a series of 4 + 2 spare dipoles. The short model was delivered to CERN and successfully tested in a vertical cryostat in summer 2020, reaching nominal current after three quenches in the second thermal cycle, validating most of the mechanical, thermal and electrical design and giving indications for improvements that have been implemented in the prototype, which was completed and delivered to CERN in October 2021. It was tested in October 2022 in its final cold mass, 14 m long, which also includes the two orbit correctors. This contribution reports on key results from the prototype tests and on the further activities related to the construction of the first magnets of the series
Application of next generation sequencing to identify causative variants at the BCL11A locus
No full textSevere Toxoplasma gondii infection in a member of a NFKB2-deficient family with T and B cell dysfunction
No full text
