Luisa Gennero

Glioblastoma cancer stem cells: heterogeneity, microenvironment and related therapeutic strategies

Glioblastoma Multiforme (GBM) is an incurable malignancy. GBM patients have a short life expectancy despite aggressive therapeutic approaches based on surgical resection followed by adjuvant radiotherapy and concomitant chemotherapy. Glioblastoma growth is characterized by a high motility of tumour cells, their resistance to both chemo/radio‐therapy, apoptosis inhibition leading to failure of conventional therapy. Cancer Stem Cells (CSCs), identified in GBM as well as in many other cancer types, express the membrane antigen prominin‐1 (namely CD133). These cells and normal Neural Stem Cells (NSC) share surface markers and properties, i.e. are able to self‐renew and differentiate into multiple cell types. Stem cell self‐renewal depends on microenvironmental cues, including Extracellular Matrix (ECM) composition and cell types. Therefore, the role of microenvironment needs to be evaluated to clarify its importance in tumour initiation and progression through CSCs. The specific microenvironment of CSCs was found to mimic in part the vascular niche of normal stem cells. The targeting of GMB CSCs may represent a powerful treatment approach. Lastly, in GBM patients cancer‐initiating cells contribute to the profound immune suppression that in turn correlated with CSCs STAT3 (CD133 + ). Further studies of microenvironment are needed to better understand the origin of GMB/GBM CSCs and its immunosuppressive properties. Copyright

The anti-HIV-1 activity of chloroquine

BACKGROUND there is a dramatic need for drugs with anti-HIV-1 activity that are affordable for resource-poor countries. Chloroquine (CQ) is one such drug. OBJECTIVES to review the data indicating that CQ has anti-HIV-1 activity. RESULTS chloroquine (CQ) and its derivative hydroxychloroquine (HCQ) are endowed with a broad anti-HIV-1 activity inhibiting X4, R5, and X4/R5 stains in lymphocytic and monocytic cells. Interestingly, CQ is capable of inhibiting HIV-1 replication at concentrations within the range reported in plasma of individuals chronically treated with doses of the drug which have well-known and limited toxicity. These effects have been confirmed in vivo in two clinical trials. The principal mechanism of HIV-1 inhibition by CQ seems to be an effect on gp120 on a post-transcriptional level. Because CQ and HCQ appear to have a novel site of action (i.e. post-transcriptional inhibition of gp120), these drugs may be particularly useful in combination with other anti-retroviral agents (e.g. ZDV, ddI and HU). CONCLUSION combining these drugs with other anti-HIV-1 agents, especially HU and ddI, may be an interesting option for the treatment for HIV-1 infected individuals in the developing world.

Pre-eclampsia is associated with Helicobacter pylori seropositivity in Italy.

Objectives Pre-eclampsia (PE) is characterized by an excess of inflammation and endothelial dysfunction. Helicobacter pylori (H. pylori) causes chronic inflammatory changes and endothelial damage. We investigated the prevalence of seropositivity for IgG against H. pylori and cytotoxin-associated antigen A (CagA) in PE patients and the presence of H. pylori DNA in their placentas. Methods We tested 47 pregnant women with PE and 47 with uneventful pregnancies for serum antibodies against H. pylori (enzyme immunoassays) and CagA protein (immunoblot assays). In 20 of them (10 normal and 10 PE) we assessed the presence, in the placenta, of H. pylori DNA by means of nested polymerase chain reaction (PCR). The odds ratios (OR) and 95% confidence intervals (CI), adjusted for parity, were calculated using logistic regression analysis to assess the risk of PE associated with H. pylori infection. Results Helicobacter pylori seropositivity frequency was higher in mothers with PE (51.1%) compared to women with uneventful pregnancy (31.9%) (OR, 2.668; 95% CI, 1.084–6.566; P = 0.033). The difference was even greater for CagA seropositivity (80.9 and 14.9%, respectively) (OR, 26.035; 95% CI, 8.193–82.729; P < 0.001). All placentas were negative for H. pylori DNA. Conclusions Helicobacter pylori, and especially strains carrying the CagA gene, may contribute to the inflammatory mechanisms involved in the pathogenesis of PE.

Role of iron metabolism and oxidative damage in postmenopausal bone loss

It has been suggested that iron-deficient rats have lower bone mass than iron-replete animals, but a clear association between bone and iron repletion has not been demonstrated in humans. A growing body of evidences also suggests a relation between lipid oxidation and bone metabolism and between iron metabolism and LDL oxidation. Iron availability to cells also depends on haptoglobin (Hp) phenotypes. Hp has also important antioxidant properties according to its phenotype, hence we evaluate whether Hp phenotype could influence bone density, iron metabolism and lipid oxidation. This cross-sectional study enrolled 455 postmenopausal women affected by osteoporosis (260) or not (195). Bone mineral density, markers of bone and iron metabolism, levels of oxidized LDL (oxLDL) and Hp phenotype were measured in all the subjects. Hp 1.1 and 2.2 frequency was higher and Hp 2.1 was lower in the patients with fragility fractures (80) compared with the controls. We therefore evaluate different Hp phenotypes as risk or protective factors against fragility fracture: Hp 2.1 is a protective factor against fracture while 1.1 is an important and 2.2 a moderate risk factor for fragility fractures. Lower serum iron was associated with elevated transferrin in patients with Hp 1.1; moreover patients had relative iron deficiency compared with the controls and fractured patients had higher level of oxLDL. We found that both iron metabolism and oxLDL varies according to Hp phenotypes and are predictive of bone density. Our data indicate that Hp 2.1 is a protective factor for fragility fractures, depending on its role on iron metabolism and its antioxidant properties.

Impaired macrophage phagocytosis of apoptotic neutrophils in patients with human immunodeficiency virus type 1 infection.

ABSTRACT Dysfunction of neutrophils (polymorphonuclear leukocytes [PMNL]) and macrophagic cells occurs as a consequence of human immunodeficiency virus type 1 (HIV-1) infection. Macrophages contribute to the resolution of early inflammation ingesting PMNL apoptotic bodies. This study investigated macrophage ability to phagocytose PMNL apoptotic bodies in patients with HIV-1 infection in comparison with uninfected individuals and the effect of HIV Nef protein on apoptotic body phagocytosis to determine if phagocytic activity is impaired by HIV infection. Monocytes/macrophages were isolated from 10 HIV-1-infected patients and from five healthy volunteers, whereas PMNL were isolated from healthy volunteers. Macrophage phagocytosis of apoptotic PMNL was determined by staining of apoptotic bodies with fluorescein-conjugated concanavalin A or with fluorescein-labeled phalloidin. Our data show significant impairment of PMNL apoptotic body macrophage phagocytosis in subjects with HIV-1 infection presenting a concentration of CD4+ T lymphocytes of >200/mm3 and in particular in those with <200 CD4+ T lymphocyte cells/mm3. In addition, HIV-1 recombinant Nef protein is able to decrease phagocytosis of apoptotic PMNL from normal human macrophages in a dose-dependent manner. The results of our study suggest that impaired macrophage phagocytosis of PMNL apoptotic bodies may contribute to the persistence of the inflammatory state in HIV-infected subjects, especially during opportunistic infections that are often favored by defective phagocytic activity.

Microparticles in physiological and in pathological conditions.

Chronic diseases pose a severe burden to modern National Health Systems. Individuals nowadays have a far more extended lifespan than in the past, but healthy living was only scantily extended. As much as longer life is desirable, it is saddened by chronic diseases and organ malfunctions. One contributor to these problems was recognized to be represented by microparticles (MPs). Our purpose is to better understand MPs, to contrast their ominous threat and possible clinical importance. For this intent we correlated MPs with thrombotic pathologies, hemophilia, malaria, diabetes, cardiovascular diseases, endothelial dysfunctions, pulmonary hypertension, ischemic stroke, pre‐eclampsia, rheumatologic diseases—rheumatoid arthritis, polymyositis—dermatomyositis, angiogenesis and tumor progression—cancer; we listed the possibilities of using them to improve transfusion methods, as a marker for acute allograft rejection, in stem cell transplantation, as neuronal biomarkers, to understand gender‐specific susceptibility for diseases and to improve vaccination methods and we presented some methods for the detection of MPs. Copyright

Modulation of surface transferrin receptors in lymphoid cells de novo infected with human immunodeficiency virus type-1.

To investigate whether transferrin receptor (CD71) expression is affected by acute HIV‐1 infection, three different lymphoid cell lines (MT‐4, SUPT‐1, H9) were infected with HIV‐1 and tested for surface CD71 expression after different incubation periods depending on cell survival after infection. We found that expression of surface CD71 was lower in cells infected with HIV‐1 than in uninfected controls: the timing and extent of this down‐modulation depended apparently on the different susceptibility of the cell lines to HIV‐1 infection and cytopathogenicity. Citrate, a molecule capable of chelating iron, dose‐dependently prevented down‐modulation of surface CD71 in HIV‐1 infected cells as well as viral cytopathic effects. We conclude that (i) expression of surface transferrin receptors is down‐modulated by acute HIV‐1 infection in T lymphoid cells, that (ii) this cell phenotypic modulation is associated with the cytopathic effects of the virus, and that (iii) these phenomena are modulated by iron chelation. These results support the view that iron metabolism may be an important area for interaction between HIV‐1 and human cells. Copyright

Pluripotent plasticity of stem cells and liver repopulation

Different types of stem cells have a role in liver regeneration or fibrous repair during and after several liver diseases. Otherwise, the origin of hepatic and/or extra‐hepatic stem cells in reactive liver repopulation is under controversy. The ability of the human body to self‐repair and replace the cells and tissues of some organs is often evident. It has been estimated that complete renewal of liver tissue takes place in about a year. Replacement of lost liver tissues is accomplished by proliferation of mature hepatocytes, hepatic oval stem cells differentiation, and sinusoidal cells as support. Hepatic oval cells display a distinct phenotype and have been shown to be a bipotential progenitor of two types of epithelial cells found in the liver, hepatocytes, and bile ductular cells. In gastroenterology and hepatology, the first attempts to translate stem cell basic research into novel therapeutic strategies have been made for the treatment of several disorders, such as inflammatory bowel diseases, diabetes mellitus, celiachy, and acute or chronic hepatopaties. In the future, pluripotent plasticity of stem cells will open a variety of clinical application strategies for the treatment of tissue injuries, degenerated organs. The promise of liver stem cells lie in their potential to provide a continuous and readily available source of liver cells that can be used for gene therapy, cell transplant, bio‐artificial liver‐assisted devices, drug toxicology testing, and use as an in vitro model to understand the developmental biology of the liver. Copyright

Sub-epitopic dissection of HCV E1315–328HRMAWDMMMNWSPT sequence by similarity analysis

Summary.Our labs are focused on identifying amino acid sequences having the ability to react specifically with the functional binding site of a complementary antibody. Our epitopic definition is based on the analysis of the similarity level of antigenic amino acid sequences to the host proteome. Here, the similarity profile to the human proteome of an HCV E1 immunodominant epitope, i.e. the HCV E1315–328HRMAWDMMMNWSPT sequence, led to i) characterizing the immunoreactive HCV E1 315–328 region as a sequence endowed with a low level of similarity to human proteins; ii) defining 2 contiguous immunodominant linear determinants respectively located at the NH2 and COOH terminus of the conserved viral antigenic sequence. This study supports the hypothesis that low sequence similarity to the host’s proteome modulates the pool of epitopic amino acid sequences in a viral antigen, and appears of potential value in defining immunogenic viral peptide sequences to be used in immunotherapeutic approaches for HCV treatment.

Serum Citrate Levels, Haptoglobin Haplotypes and Transferrin Receptor (CD71) in Patients With HIV-1 Infection

AbstractBackground: The progression of HIV-1 infection towards its more advanced stages is accompanied by changes in iron metabolism and increased body iron stores. Patients and Methods: Given the ability of HIV to alter iron metabolism, we studied the principal (transferrin system) and alternative (citrate system) iron pathways in a group of 65 HIV-infected patients (symptomatic stage B1–B3) and in a group of 36 healthy seronegative individuals. We determined serum citrate levels, haptoglobin (Hp) haplotypes, expression of transferrin receptor (CD71) on cell lines infected with HIV-1 as well as iron markers including blood iron, transferrin and ferritin. Results: Our data showed decreased serum citrate levels in the HIV-infected patients compared to controls (92.9 ± 22.4 μM/l vs 126.2 ± 29.2 μM/l; p < 0.01). In particular, the serum citrate levels negatively correlated with HIV-1 RNA copy number (mean: 2.53 ± 1.88 × 105/ml, rs = 0.70, p < 0.01) and positively correlated with CD4+ T-lymphocyte count (mean: 241 ± 168/ml, rs = 0.64, p > 0.05). Accordingly, blood iron, transferrin and red cell concentrations were lower in HIV-infected patients compared to the controls, whereas serum ferritin levels were higher in HIV-infected patients. Moreover, the Hp haplotype distribution showed significant differences only in the group of HIV-infected patients (p = 0.02; χ2 test). Conclusion: Our results show that iron metabolism is altered in patients with HIV-1 infection. The alternative pathway (citrate system) is particularly affected, since when citrate levels are low, both aconitase activity and HIV-1 replication need iron.