Essays on Coalition Formation Theory

The thesis is a contribution to Coalition Formation Theory. Coalition formation theory is the collection of disciplines and mathematical tools which deals with the analysis of coalition formation processes. A coalition formation process is a process by which agents get together to coordinate their actions in order to achieve shared goals. Coalition formation is an important and recurrent pattern in human behavior and many social phenomena can be studied in terms of coalition formation processes. Examples are: cartel formation, environmental agreements, political party formation, lobbying and the of a local public good. The thesis provide a new tool to analyse coalition formation processes and to predict the behaviour of the agents involved in the processes. From one side, our new tool connects and generalizes different existing tools; from another side it is able to provide predictions even when the other tools fails

The role of epidemiology within HTA: a systematic review of epidemiological methods in assessing the burden of cardiovascular disease risk factors

n/

Sterol metabolism modulates susceptibility to HIV-1 Infection

Background: 25-hydroxylase (CH25H) is an Interferon stimulated gene (ISG), which catalyzes the synthesis of 25-Hydroxycholesterol (25HC). 25HC intervenes in metabolic and infectious processes as controls cholesterol homeostasis and influences viral entry into host cells.We verified whether natural resistance to HIV-1 infection in HIV-1-exposed seronegative (HESN) individuals is at least partially mediated by particularities in sterol biosynthesis. Methods: Peripheral blood mononuclear cells (PBMCs) and monocyte-derived macrophages (MDMs) isolated from 15 sexually-exposed HESN and 15 healthy controls (HC) were in vitro HIV-1-infected and analyzed for: 1) percentage of IFN\u3b1-producing plasmacytoid Dendritic Cells (pDCs); 2) Cholesterol signaling and inflammatory response RNA expression; 3) resistance to HIV-1 infection. MDMs from 5 HC were in vitro HIV-1-infected in the absence/presence of exogenously added 25HC. Results: IFN\u3b1-producing pDCs were augmented in HESN compared to HCs both in unstimulated and in in vitro HIV-1-infected PBMCs (p<0.001). An increased expression of CH25H and of a number of genes involved in cholesterol metabolism (ABCA1, ABCG1, CYP7B1, LXR\u3b1, OSBP, PPAR\u3b3, SCARB1) was observed as well; this, was associated with a reduced susceptibility to in vitro HIV-1-infection of PBMCs and MDMs (p<0.01). Notably, addition of 25HC to MDMs resulted in increased cholesterol efflux and augmented resistance to in vitro HIV-1-infection. Conclusions: Results herein show that in HESN sterol metabolism might be particularly efficient. This could be related to the activation of the IFN\u3b1 pathway and results into a reduced susceptibility to in vitro HIV-1 infection. These results suggest a possible basis for therapeutic interventions to modulate HIV-1 infection

Endoplasmic Reticulum Associated Aminopeptidase 2 (ERAP2) is released in the secretome of activated MDMs and reduces in vitro HIV-1 infection

Background: Haplotype-specific alternative splicing of the endoplasmic reticulum (ER) aminopeptidase type 2 (ERAP2) gene results in either full-length (FL, haplotype A) or alternatively spliced (AS, haplotype B) mRNA. HapA/HapA homozygous (HomoA) subjects show a reduced susceptibility to HIV-1 infection, probably secondary to the modulation of the antigen processing/presenting machinery. ERAP1 was recently shown to be secreted from the plasma membrane in response to activation; we investigated whether ERAP2 can be released as well and if the secreted form of this enzyme retains its antiviral function. Methods: Human monocyte derived macrophages (MDMs) were differentiated from peripheral blood mononuclear cells (PBMCs) isolated from 6 HomoA healthy controls and stimulated with IFN\u3b3 and LPS. ERAP2-FL secretion was evaluated by mass spectrometry. PBMCs (14 HomoA and 16 HomoB) and CD8-depleted PBMCs (CD8-PBMCs) (4 HomoA and 4 HomoB) were in vitro HIV-infected in the absence/presence of recombinant human ERAP2-FL (rhERAP2) protein; p24 viral antigen quantification was used to assess viral replication. IFN\u3b3 and CD69 mRNA expression, as well as the percentage of perforin-producing CD8+ T Lymphocytes, were analyzed 3 and 7-days post in vitro HIV-1-infection, respectively. The effect of rhERAP2 addition in cell cultures on T cell apoptosis, proliferation, activation, and maturation was evaluated as well on 24 h-stimulated PBMCs. Results: ERAP2 can be secreted from human MDMs in response to IFN\u3b3/LPS stimulation. Notably, the addition of rhERAP2 to PBMC and CD8-PBMC cultures resulted in the reduction of viral replication, though these differences were statistically significant only in PBMCs (p < 0.05 in both HomoA and HomoB). This protective effect was associated with an increase in IFN\u3b3 and CD69 mRNA expression and in the percentage of perforin-expressing CD107+CD8+ cells. RhERAP2 addition also resulted in an increase in CD8+ activated lymphocyte (CD25+HLA-DRII+) and Effector Memory/Terminally differentiated CD8+ T cells ratio. Conclusions: This is the first report providing evidence for the release of ERAP2 in the secretome of immunocompetent cells. Data herein also indicate that exogenous ERAP2-FL exerts its protective function against HIV-1 infection, even in HomoB subjects who do not genetically produce it. Presumably, this defensive extracellular feature is only partially dependent on immune system modulation

Plasma and PBMC miRNA profile in sexually HIV-1 exposed seronegative individuals

Background: MicroRNAs (miRNAs) are small 20- to 24-nt non-coding RNAs involved in the post-transcriptional regulation of gene expression which play important defensive roles in several viral infections. Global expression profiles of cellular miRNAs have identified alterations of specific miRNAs post-HIV-1 infection both in vitro and in different patient cohorts suggesting potential roles for miRNA in pathogenesis and disease progression. We therefore decided to verify if natural resistance to HIV-1 infection observed in seronegative individuals repeatedly exposed to HIV-1 (HESN) through unprotected sexual intercourse could be secondary to a different expression of their miRNA profile. Methods: Expression levels of 25 miRNAs selected according to their proven anti-HIV-1 properties were analyzed in plasma, basal PBMC and in in vitro HIV-1 infected macrophages isolated from 30 HESN, 30 HIV seropositive subjects (HIV + ) and 30 healthy controls (HC).Results: In plasma the expression of mir-155, mir-382, mir-28 and mir-198 was significantly augmented in both HIV + and HESN compared to HC probably as a consequence of viral exposure. Conversely the expression of mir-223 and mir-150 in plasma was significantly increased only in HESN and this result was also confirmed in basal PBMC suggesting a protective effect for these miRNAs in resistance to HIV-1 infection. Furthermore, the expression of mir-150 was significantly increased in HESN macrophages following HIV-1 infection. Conclusions: mir-223 and mir-150 can target the 3\ua2UTR of HIV-1 transcripts, and they have already been identified as anti-HIV-1 miRNAs. The higher expression of these miRNA in HESN samples could therefore represent a key protection mechanism against HIV infection

Thiazolides elicit anti-viral innate immunity and reduce HIV replication

Nitazoxanide (Alinia (R), NTZ) and tizoxanide (TIZ), its active circulating metabolite, belong to a class of agents known as thiazolides (TZD) endowed with broad anti-infective activities. TIZ and RM-4848, the active metabolite of RM-5038, were shown to stimulate innate immunity in vitro. Because natural resistance to HIV-1 infection in HIV-exposed seronegative (HESN) individuals is suggested to be associated with strong innate immune responses, we verified whether TIZ and RM-4848 could reduce the in vitro infectiousness of HIV-1. Peripheral blood mononuclear cells (PBMCs) from 20 healthy donors were infected in vitro with HIV-1(BaL) in the presence/absence of TIZ or RM4848. HIV-1 p24 were measured at different timepoints. The immunomodulatory abilities of TZD were evaluated by the expression of type I IFN pathway genes and the production of cytokines and chemokines. TZD drastically inhibited in vitro HIV-1 replication (>87%). This was associated with the activation of innate immune responses and with the up-regulation of several interferon-stimulated genes (ISGs), including those involved in cholesterol pathway, particularly the cholesterol-25 hydroxylase (CH25H). TZD inhibition of HIV-1 replication in vitro could be due to their ability to stimulate potent and multifaceted antiviral immune responses. These data warrant the exploration of TZD as preventive/therapeutic agent in HIV infection

A Genotyping-by-Sequencing approach brings new insights into the population structure and local adaptation of Western Mediterranean Oaks

XIX ENBE Annual Meeting of the Portuguese Association for Evolutionary Biology, 18-19 December 2023, Lisboninfo:eu-repo/semantics/publishedVersio

A regulatory polymorphism in HAVCR2 modulates susceptibility to HIV-1 infection

The HAVCR2 gene encodes TIM-3, an immunoglobulin superfamily member expressed by exhausted CD8+ T cells during chronic viral infection. We investigated whether genetic variation at HAVCR2 modulates the susceptibility to HIV-1 acquisition; specifically we focused on a 3\u2032 UTR variant (rs4704846, A/G) that represents a natural selection target. We genotyped rs4704846 in three independent cohorts of HIV-1 exposed seronegative (HESN) individuals with different geographic origin (Italy and Spain) and distinct route of exposure to HIV-1 (sexual and injection drug use). Matched HIV-1 positive subjects and healthy controls were also analyzed. In all case-control cohorts the minor G allele at rs4704846 was more common in HIV-1 infected individuals than in HESN, with healthy controls showing intermediate frequency. Results from the three association analyses were combined through a random effect meta-analysis, which revealed no heterogeneity among samples (Cochrane's Q, p value = 0.89, I2 = 0) and yielded a p value of 6.8 710 124. The minor G allele at rs4704846 was found to increase HAVCR2 expression after in vitro HIV-1 infection. Thus, a positively selected polymorphism in the 3\u2032 UTR, which modulates HAVCR2 expression, is associated with the susceptibility to HIV-1 infection. These data warrant further investigation into the role of TIM-3 in the prevention and treatment of HIV-1/AIDS

A Small Molecule SMAC Mimic LBW242 Potentiates TRAIL- and Anticancer Drug-Mediated Cell Death of Ovarian Cancer Cells

BACKGROUND: Ovarian cancer remains a leading cause of death in women and development of new therapies is essential. Second mitochondria derived activator of caspase (SMAC) has been described to sensitize for apoptosis. We have explored the pro-apoptotic activity of LBW242, a mimic of SMAC/DIABLO, on ovarian cancer cell lines (A2780 cells and its chemoresistant derivative A2780/ADR, SKOV3 and HEY cells) and in primary ovarian cancer cells. The effects of LBW242 on ovarian cancer cell lines and primary ovarian cancer cells was determined by cell proliferation, apoptosis and biochemical assays. PRINCIPAL FINDINGS: LBW242 added alone elicited only a moderate pro-apoptotic effect; however, it strongly synergizes with tumor necrosis factor-related apoptosis inducing ligand (TRAIL) or anticancer drugs in inducing apoptosis of both ovarian cancer cell lines and primary ovarian cancer cells. Mechanistic studies show that LBW242-induced apoptosis in ovarian cancer cells is associated with activation of caspase-8. In line with this mechanism, c-FLIP overexpression inhibits LBW242-mediated apoptosis. CONCLUSION: LBW242 sensitizes ovarian cancer cells to the antitumor effects of TRAIL and anticancer drugs commonly used in clinic. These observations suggest that the SMAC/DIABLO mimic LBW242 could be of value for the development of experimental strategies for treatment of ovarian cancer