Francisco Dasí

Stability of PEI–DNA and DOTAP–DNA complexes: effect of alkaline pH, heparin and serum

DNA complexes formed with nonviral vectors such as polyethylenimine (PEI) or 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) are widely used in gene therapy. These complexes prevent the interaction of DNA with the fluorescent probes usually employed to quantify DNA. We thus studied the procedures for DNA quantification from DNA complexes as well as their stability in the presence of DNase or mouse, rat and human sera. Release of the DNA from its complexes was accomplished by increasing the pH of the medium (from 7.3 to 13.4) or by adding heparin. The stability against degradation was tested in vitro, by incubating the complexes at 37 degrees C in the presence of DNase I and sera from the three species. Both high pH and heparin were able to release DNA from its complexes. Naked DNA formed aggregates with serum proteins that delayed electrophoresis migration, and this effect was reversed in the presence of heparin. However, these aggregates did not protect DNA from digestion by serum DNase, and the DNA digesting ability of serum was: mouse>rat>human. The DNA from the complexes was resistant to degradation by DNase I, although a low proportion of DNA from the complexes was partially digested, as determined by electrophoresis. In contrast, PEI-DNA and DOTAP-DNA complexes were stable in the presence of all sera. Heparin and high pH release DNA from its complexes. The order of DNA degradation is: mouse>rat>human, but DOTAP and PEI avoid degradation of DNA by serum compounds.

Real-Time Quantification in Plasma of Human Telomerase Reverse Transcriptase (hTERT) mRNA: A Simple Blood Test to Monitor Disease in Cancer Patients

Real-Time Quantification in Plasma of Human Telomerase Reverse Transcriptase (hTERT) mRNA: A Simple Blood Test to Monitor Disease in Cancer Patients

Mitochondrial dysfunction, persistent oxidative damage, and catalase inhibition in immune cells of naïve and treated Crohn's disease

Background: Oxidative stress is considered a potential etiological factor for Crohns disease (CD). We characterized the reactive oxygen species (ROS) generated in immune peripheral cells of CD patients, as well as their antioxidant enzyme status and the presence of oxidative damage. In addition, mitochondrial function (&Dgr;&ggr;m) was analyzed to detect the possible origin of ROS. Methods: Cells were obtained from patients at the onset of disease, prior to any treatment. Experiments were repeated when patients were in clinical remission. A set of experiments was carried out in a group of CD patients in persistent morphological remission. Controls were healthy volunteers who were not receiving any treatment at the time. The generation of superoxide, hydrogen peroxide (H2O2) and nitric oxide, &Dgr;&ggr;m, superoxide dismutase (SOD) and catalase (CAT) activities, and concentrations of malondyaldehyde (MDA) and 8‐oxo‐deoxyguanosine (8‐oxo‐dG) were measured. Results: SOD activity and H2O2 production were significantly higher during active CD but returned to control levels in remission. &Dgr;&ggr;m was inhibited during active CD and, although it returned to control levels, its recovery took longer than clinical remission. CAT activity was permanently inhibited during CD, independent of the disease activity. MDA and 8‐oxo‐dG were permanently elevated. Conclusions: Oxidative stress during active CD depends on H2O2 production. The inhibition of &Dgr;&ggr;m suggests that this organelle is a source of ROS. CAT is permanently inhibited in CD, the biological significance of which is under study. The persistent oxidative damage detected may have implications for the evolution of the disease. Inflamm Bowel Dis 2010

Histone H3 Glutathionylation in Proliferating Mammalian Cells Destabilizes Nucleosomal Structure

AIMS Here we report that chromatin, the complex and dynamic eukaryotic DNA packaging structure, is able to sense cellular redox changes. Histone H3, the only nucleosomal protein that possesses cysteine(s), can be modified by glutathione (GSH). RESULTS Using Biotin labeled glutathione ethyl ester (BioGEE) treatment of nucleosomes in vitro, we show that GSH, the most abundant antioxidant in mammals, binds to histone H3. BioGEE treatment of NIH3T3 cells indicates that glutathionylation of H3 is maximal in fast proliferating cells, correlating well with enhanced levels of H3 glutathionylation in different tumor cell lines. Furthermore, glutathionylation of H3 in vivo decreases in livers from aged SAMP8 and C57BL/6J mice. We demonstrate biochemically and by mass spectrometry that histone variants H3.2/H3.3 are glutathionylated on their cysteine residue 110. Furthermore, circular dichroism, thermal denaturation of reconstituted nucleosomes, and molecular modeling indicate that glutathionylation of histone H3 produces structural changes affecting nucleosomal stability. INNOVATION We characterize the implications of histone H3 glutathionylation in cell physiology and the modulation of core histone proteins structure affected by this modification. CONCLUSION Histone H3 senses cellular redox changes through glutathionylation of Cys, which increases during cell proliferation and decreases during aging. Glutathionylation of histone H3 affects nucleosome stability structure leading to a more open chromatin structure.

Cell-Free Circulating Plasma hTERT mRNA Is a Useful Marker for Prostate Cancer Diagnosis and Is Associated with Poor Prognosis Tumor Characteristics

Background Serum prostate-specific antigen (PSA) is the most widely used marker for diagnosing prostate cancer (PCa). It lacks specificity and predictive value, resulting in inaccurate diagnoses and overtreatment of the disease. The aim of this study was to assess the usefulness of plasma telomerase reverse transcriptase (hTERT) mRNA as a diagnostic and prognostic tool for PCa and its association with clinicopathological parameters of tumors. Principal Findings Plasma hTERT mRNA levels were determined by qRT-PCR in 105 consecutive patients with elevated PSA levels and in 68 healthy volunteers. The diagnostic accuracy, the efficacy as a prognostic factor of biochemical recurrence and the association with tumor clinicopathological parameters of plasma hTERT mRNA and serum PSA tests were determined using univariate and multivariate analyses. The results show that plasma hTERT mRNA is a non-invasive biomarker for PCa diagnosis that shows higher sensitivity (85% vs. 83%), specificity (90% vs. 47%), positive predictive value (83% vs. 56%), and negative predictive value (92% vs. 77%) than serum PSA. Plasma hTERT mRNA is significantly associated with poor prognosis tumor clinicopathological parameters and is a significant independent predictor of PCa (p<0.0001). Univariate analysis identified plasma hTERT mRNA (but not serum PSA) as a significant prognostic factor of biochemical recurrence. Plasma hTERT mRNA Kaplan-Meier curves confirmed the significant differences between groups and patients with higher levels than the cut-off value showed diminished recurrence-free survival (p = 0.004), whereas no differences were observed with serum PSA (p = 0.38). Multivariate analysis indicated that plasma hTERT mRNA (but not serum PSA) and stage were significantly associated with biochemical recurrence. Conclusions Overall, these findings indicate that hTERT mRNA is a useful non-invasive tumor marker for the molecular diagnosis of PCa, affording a greater diagnostic and prognostic accuracy than the PSA assay and may be of relevance in the follow-up of the disease.

Cytokine expression and dendritic cell density in melanoma sentinel nodes.

The sentinel lymph node (SLN) is the first draining node from the area in which a tumour is located. The presence or absence of SLN micrometastasis is an important prognostic factor for melanoma. As the first dissemination route for melanoma is lymphatic and we know that the immune system plays an important role in melanoma response, we hypothesize that melanoma and its corresponding SLN should constitute an immunological unit. Small portions of 54 SLNs from 37 patients undergoing selective lymphadenectomy were subjected to quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) to quantify messenger RNA (mRNA) transcripts of the following genes: tyrosinase, telomerase, cyclooxygenase-1 (COX-1), COX-2, granulocyte–macrophage colony-stimulating factor (GM-CSF), interleukin-2 (IL-2), interferon-&ggr; (IFN-&ggr;), IL-4, IL-10 and IL-12. In addition, 11 non-sentinel lymph nodes (NSLNs) were excised from 11 of the 37 patients and the same study was performed. Immunohistochemistry with different antibodies against dendritic cells (DCs) was performed in 10 pairs of SLNs and NSLNs. Significantly higher mRNA expression of COX-2, GM-CSF, IFN-&ggr; and IL-10 was found in SLNs compared with NSLNs in the overall group. DCs, as labelled by S-100 and CD1a, were significantly decreased in NSLNs compared with SLNs. These data suggest that the initial increase in GM-CSF observed in SLNs could lead to the attraction of a high number of DCs to SLNs. However, the presence of certain immunosuppressive molecules, such as IL-10 and COX-2, could block their maturation and their ability to become efficient antigen presenters.

Real‐Time Quantification of Human Telomerase Reverse Transcriptase mRNA in the Plasma of Patients with Prostate Cancer

Abstract:  The aim of this study was to evaluate the potential diagnostic value of quantitative analysis of human telomerase reverse transcriptase (hTERT) mRNA in plasma for noninvasive diagnosis of prostate cancer (PCa). Expression levels of hTERT were analyzed by real‐time quantitative RT‐PCR in 68 patients showing elevated prostate‐specific antigen (PSA) levels and a control group of 44 healthy volunteers. Sensitivity and specificity were determined and compared to the corresponding PSA values. Median values for hTERT gene expression in the PCa patients (0.72 ng; range 0.01–12.86) were statistically significantly higher (P < 0.001) than in the control group (0.13 ng; 0.02–0.35). Patients with clinically confirmed prostatitis showed lower plasma hTERT expression than PCa patients (0.29; 0.01–66.07). At a cutoff value of 0.35 sensitivity and specificity for the diagnosis of PCa were 81% and 60%, respectively. We suggest that hTERT mRNA in plasma is a very specific and sensitive method that may aid to differentiate between malignant and nonmalignant prostate tissue and may be a useful marker (in combination with PSA) for early PCa diagnosis.

Differential Expression of PGC-1α and Metabolic Sensors Suggest Age-Dependent Induction of Mitochondrial Biogenesis in Friedreich Ataxia Fibroblasts

Background Friedreichs ataxia (FRDA) is a mitochondrial rare disease, which molecular origin is associated with defect in the expression of frataxin. The pathological consequences are degeneration of nervous system structures and cardiomyopathy with necrosis and fibrosis, among others. Principal Findings Using FRDA fibroblasts we have characterized the oxidative stress status and mitochondrial biogenesis. We observed deficiency of MnSOD, increased ROS levels and low levels of ATP. Expression of PGC-1α and mtTFA was increased and the active form of the upstream signals p38 MAPK and AMPK in fibroblasts from two patients. Interestingly, the expression of energetic factors correlated with the natural history of disease of the patients, the age when skin biopsy was performed and the size of the GAA expanded alleles. Furthermore, idebenone inhibit mitochondriogenic responses in FRDA cells. Conclusions The induction of mitochondrial biogenesis in FRDA may be a consequence of the mitochondrial impairment associated with disease evolution. The increase of ROS and the involvement of the oxidative phosphorylation may be an early event in the cell pathophysiology of frataxin deficiency, whereas increase of mitochondriogenic response might be a later phenomenon associated to the individual age and natural history of the disease, being more evident as the patient age increases and disease evolves. This is a possible explanation of heart disease in FRDA.

Reductive stress in young healthy individuals at risk of Alzheimer disease.

Oxidative stress is a hallmark of Alzheimer disease (AD) but this has not been studied in young healthy persons at risk of the disease. Carrying an Apo ε4 allele is the major genetic risk factor for AD. We have observed that lymphocytes from young, healthy persons carrying at least one Apo ε4 allele suffer from reductive rather than oxidative stress, i.e., lower oxidized glutathione and P-p38 levels and higher expression of enzymes involved in antioxidant defense, such as glutamylcysteinyl ligase and glutathione peroxidase. In contrast, in the full-blown disease, the situation is reversed and oxidative stress occurs, probably because of the exhaustion of the antioxidant mechanisms just mentioned. These results provide insights into the early events of the progression of the disease that may allow us to find biomarkers of AD at its very early stages.

Oxidative Stress Parameters in Saliva and Its Association with Periodontal Disease and Types of Bacteria.

Objective. To determine the association between oxidative stress parameters with periodontal disease, bleeding, and the presence of different periodontal bacteria. Methods. A cross-sectional study in a sample of eighty-six patients, divided into three groups depending on their periodontal status. Thirty-three with chronic periodontitis, sixteen with gingivitis, and thirty-seven with periodontal healthy as control. Oxidative stress biomarkers (8-OHdG and MDA), total antioxidant capacity (TAOC), and the activity of two antioxidant enzymes (GPx and SOD) were determined in saliva. Subgingival plaque samples were obtained from the deepest periodontal pocket and PCR was used to determine the presence of the 6 fimA genotypes of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Treponema denticola. Results. Periodontal disease was found to be associated with increased oxidative stress parameter levels. These levels rose according to the number and type of different periodontal bacteria found in the periodontal pockets. The presence of different types of periodontal bacteria is predictive independent variables in linear regresion models of oxidative stress parameters as dependent variable, above all 8-OHdG. Conclusions. Oxidative stress parameter levels are correlated with the presence of different types of bacteria. Determination of these levels and periodontal bacteria could be a potent tool for controlling periodontal disease development.