Prion diseases are characterized by prion protein (PrP) transmissible aggregation and neurodegeneration, which has been linked to oxidative stress. The physiological function of PrP seems related to sequestering of redox-active Cu ²⁺ , and Cu ²⁺ dyshomeostasis is observed in prion disease brain. It is unclear whether Cu ²⁺ contributes to PrP aggregation, recently shown to be mediated by PrP condensation. This study indicates that Cu ²⁺ promotes PrP condensation in live cells at the cell surface and in vitro through copartitioning. Molecularly, Cu ²⁺ inhibited PrP β-structure and hydrophobic residues exposure. Oxidation, induced by H ₂ O ₂ , triggered liquid-to-solid transition of PrP:Cu ²⁺ condensates and promoted amyloid-like PrP aggregation. In cells, overexpression of PrP ^C initially protected against Cu ²⁺ cytotoxicity but led to PrP ^C aggregation upon extended copper exposure. Our data suggest that PrP condensates function as a buffer for copper that prevents copper toxicity but can transition into PrP aggregation at prolonged oxidative stress.

The mechanism of immunosuppression induced by severe sepsis is not fully understood. The production of prostaglandin E₂ (PGE₂) during sepsis is well known, but its role in long-term consequences of sepsis has not been explored. The current study evaluates the role of PGE₂ in the development of immunosuppression secondary to sepsis and its potential as therapeutic target. Cecal ligation and puncture was used as an experimental model for sepsis induction in Balb/c and C57BL/6 mice. Immunosuppression was evaluated by the response to secondary infection with Aspergillus fumigatus in sepsis survivors. The role of prostanoids was evaluated in vivo and in vitro by treatment with the cyclooxygenase inhibitor ketoprofen. Balb/c mice were more susceptible than C57BL/6 to severe sepsis and to secondary infection, with a greater mortality rate. Prostaglandin E₂ concentrations found in bronchoalveolar lavage in sham and cecal ligation and puncture group after fungal challenge were much higher in Balb/c than in C57BL/6 mice. Ketoprofen treatment improved survival of septic Balb/c mice subjected to secondary infection, while also enhancing macrophage phagocytosis and neutrophil recruitment to the lungs. We identified a pivotal role for PGE₂ acting on EP₄ receptors in modulating cytokine production differentially by sham and septic macrophages. Furthermore, sepsis also altered key enzymes in PGE₂ synthesis and degradation. Our results indicate the involvement of PGE₂ in severe sepsis-induced immunosuppression. Inhibition of PGE₂ production represents an attractive target to improve innate immune response against secondary infection in the immunocompromised host.

Prion diseases are characterized by prion protein (PrP) transmissible aggregation and toxicity in the brain. The physiological function of PrP seems related to sequestering and internalization of redox-active Cu ²⁺ . It is unclear whether Cu ²⁺ contributes to PrP aggregation, recently shown to be mediated by PrP condensation. We investigated the role of Cu ²⁺ and oxidation in PrP condensation and aggregation using multiple biophysical and biochemical methods. We find that Cu ²⁺ promotes PrP condensation at the cell surface and in vitro through co-partitioning. Molecularly, Cu ²⁺ inhibited PrP β-structure and hydrophobic residues exposure. Oxidation, induced by H ₂ O ₂ , triggered liquid-to-solid transition of PrP:Cu ²⁺ condensates and promoted amyloid-like PrP aggregation. In cells, overexpression of PrP ^C initially protected against Cu ²⁺ cytotoxicity but led to PrP ^C aggregation upon extended copper exposure. Our data suggest that PrP condensates function as a buffer for copper that prevent copper toxicity but can transition into PrP aggregation at prolonged oxidative stress.

Thalassemia, an autosomal recessive genetic disorder affecting production of normal globin chains, presents varying prevalence worldwide. The frequency of global α-thalassemia remains understudied, especially in Brazil, due to its genetic diversity and large population size. This study compared α-thalassemia frequency between microcytic patients and healthy volunteers in Rio de Janeiro, stratified by self-reported skin color. DNA extracted from whole blood/EDTA underwent genotyping for α-thalassemia using multiplex PCR, targeting α3.7 kb, α4.2 kb, αSEA, αMED, αFIL, and α20.5 kb deletions. Frequency of α-thalassemia among patients was 63.6%, distributed as follows: 62.1% for α3.7 kb deletion, 0.7% for α4.2 kb deletion, and 0.8% for αSEA deletion. In healthy volunteers, the prevalence was 3.2%, distributed as 0.53% in self-declared white, 1.07% in brown, and 1.60% in black individuals, all presenting heterozygous genotype for α3.7 kb deletion. Frequency in healthy population was significantly lower than that observed in microcytosis population (p < 0.001). Determining α-thalassemia frequency in highly admixed population may enhance genetic counseling, given that asymptomatic carriers can produce offspring with combinations of Hb variants, potentially leading to severe clinical phenotypes.

Germline mutations in BRCA1 have been associated with a significantly increased risk of developing breast and ovarian cancers. A large number of variants have been identified in BRCA1 and are reported as pathogenic, non-pathogenic, or as variants of uncertain significance (VUS). Test results reporting pathogenic or non-pathogenic variants can be used by physicians and genetic counselors to help patients in making important clinical decisions. Around 10-15% of the reported BRCA1 and BRCA2 variants are clearly pathogenic and 5% of these reported variants are VUS. Results reporting a VUS can cause anxiety and make it difficult to advise the patient on further clinical intervention to reduce their risk of developing the disease. Many of these VUSs are non-synonymous single amino acid changes leading to missense changes. A number of previous studies have focused on assessing the functional impact of these changes on the BRCA1 protein. BRCA1 is a gene product with pleiotropic functions and therefore, different functional assays are used in these studies to analyze the variant's impact on function. However, information on the functional impact of VUS is currently not consolidated and collecting available information on missense variants depends on multiple database searches and literature review. Moreover, methods to incorporate functional data into multifactorial models have recently been developed highlighting the need for a common resource to facilitate analysis. Realizing the need for a resource that facilitates the global visualization and analysis of these variants we have developed a visualization tool for multidimensional data using Circos (http://circos.ca) to aggregate the data from all published studies that have assessed these missense variants. Circos plots have been used in the literature to represent genomic data and we have used the same concept to illustrate variants in BRCA1. We have included ∼700 variants for which we have 30 different functional experiments from various studies assessing over 150 missense variants. Results are color coded to uniformly depict various degrees of functional impact on the BRCA1 protein function so that information for any variant can be obtained in a snapshot without having to perform extensive literature searches. Therefore, we believe clinical geneticists and genetic counselors can use this research tool as a quick reference to analyze all the missense variants that have been identified along with associated information to characterize them when faced with the challenge of advising a patient with these types of VUSs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4444. doi:1538-7445.AM2012-4444