eGFR slope as predictor of mortality in heart failure patients.

Aims: Heart failure (HF) leads to an imbalance between heart and kidney function, resulting in poor outcomes. However, the prognostic significance of the estimated glomerular filtration rate (eGFR) trajectory in HF patients remains unclear. We analysed electronic health records (EHRs) of real-world HF patients, assessing eGFR trajectories and their impact on mortality.

Unmutated RRAS2 emerges as a key oncogene in post-partum-associated triple negative breast cancer.

Background: Breast cancer (BC) is the most common cancer in women, with triple negative BC (TNBC) accounting for 20% of cases. While early detection and targeted therapies have improved overall life expectancy, TNBC remains resistant to current treatments. Although parity reduces the lifetime risk of developing BC, pregnancy increases the risk of developing TNBC for years after childbirth.

Detection of transthyretin amyloid cardiomyopathy by automated data extraction from electronic health records.

Aims: Transthyretin amyloid cardiomyopathy (ATTR-CM), a progressive and fatal cardiomyopathy, is frequently misdiagnosed or entails diagnostic delays, hindering patients from timely treatment. This study aimed to generate a systematic framework based on data from electronic health records (EHRs) to assess patients with ATTR-CM in a real-world population of heart failure (HF) patients. Predictive factors or combinations of predictive factors related to ATTR-CM in a European population were also assessed.

Recreation of an antigen-driven germinal center in vitro by providing B cells with phagocytic antigen.

Successful vaccines rely on activating a functional humoral immune response through the generation of class-switched high affinity immunoglobulins (Igs). The germinal center (GC) reaction is crucial for this process, in which B cells are selected in their search for antigen and T cell help. A major hurdle to understand the mechanisms of B cell:T cell cooperation has been the lack of an antigen-specific in vitro GC system.

A hotspot mutation targeting the R-RAS2 GTPase acts as a potent oncogenic driver in a wide spectrum of tumors.

A missense change in RRAS2 (Gln to Leu), analogous to the Gln-to-Leu mutation of RAS oncoproteins, has been identified as a long-tail hotspot mutation in cancer and Noonan syndrome. However, the relevance of this mutation for in vivo tumorigenesis remains understudied. Here we show, using an inducible knockin mouse model, that R-Ras2 triggers rapid development of a wide spectrum of tumors when somatically expressed in adult tissues.

Overexpression of wild type RRAS2, without oncogenic mutations, drives chronic lymphocytic leukemia.

Background: Chronic lymphocytic leukemia (CLL) is the most frequent, and still incurable, form of leukemia in the Western World. It is widely accepted that cancer results from an evolutionary process shaped by the acquisition of driver mutations which confer selective growth advantage to cells that harbor them. Clear examples are missense mutations in classic RAS genes (KRAS, HRAS and NRAS) that underlie the development of approximately 13% of human cancers.

Antigen presentation between T cells drives Th17 polarization under conditions of limiting antigen.

T cells form immunological synapses with professional antigen-presenting cells (APCs) resulting in T cell activation and the acquisition of peptide antigen-MHC (pMHC) complexes from the plasma membrane of the APC. They thus become APCs themselves. We investigate the functional outcome of T-T cell antigen presentation by CD4 T cells and find that the antigen-presenting T cells (Tpres) predominantly differentiate into regulatory T cells (Treg), whereas T cells that have been stimulated by Tpres cells predominantly differentiate into Th17 pro-inflammatory cells.

Vimentin as a Multifaceted Player and Potential Therapeutic Target in Viral Infections.

Vimentin is an intermediate filament protein that plays key roles in integration of cytoskeletal functions, and therefore in basic cellular processes such as cell division and migration. Consequently, vimentin has complex implications in pathophysiology. Vimentin is required for a proper immune response, but it can also act as an autoantigen in autoimmune diseases or as a damage signal.

RRAS2 shapes the TCR repertoire by setting the threshold for negative selection.

Signal strength controls the outcome of αβ T cell selection in the thymus, resulting in death if the affinity of the rearranged TCR is below the threshold for positive selection, or if the affinity of the TCR is above the threshold for negative selection. Here we show that deletion of the GTPase RRAS2 results in exacerbated negative selection and above-normal expression of positive selection markers. Furthermore, mice are resistant to autoimmunity both in a model of inflammatory bowel disease (IBD) and in a model of myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE).

Antigen phagocytosis by B cells is required for a potent humoral response.

Successful vaccines rely on activating a functional humoral response that results from promoting a proper germinal center (GC) reaction. Key in this process is the activation of follicular B cells that need to acquire antigens and to present them to cognate CD4 T cells. Here, we report that follicular B cells can phagocytose large antigen-coated particles, a process thought to be exclusive of specialized antigen-presenting cells such as macrophages and dendritic cells.

R-Ras2 is required for germinal center formation to aid B cells during energetically demanding processes.

Upon antigen recognition within peripheral lymphoid organs, B cells interact with T cells and other immune cells to transiently form morphological structures called germinal centers (GCs), which are required for B cell clonal expansion, immunoglobulin class switching, and affinity maturation. This process, known as the GC response, is an energetically demanding process that requires the metabolic reprogramming of B cells. We showed that the Ras-related guanosine triphosphate hydrolase (GTPase) R-Ras2 (also known as TC21) plays an essential, nonredundant, and B cell-intrinsic role in the GC response.

Studying the Dynamics of TCR Internalization at the Immune Synapse.

Establishing a stable interaction between a T cell and an antigen presenting cell (APC) involves the formation of an immune synapse (IS). It is through this structure that the T cell can integrate all the signals provided by the APC. The IS also serves as a mechanism for TCR downregulation through internalization.

Taking a lipidation-dependent path toward endolysosomes.

We recently reported that the isoprenylation and palmitoylation motif present at the C-terminus of human RhoB protein promotes intraluminal vesicle delivery of proteins in cells from organisms as phylogenetically apart as fungi and humans. Here we build on these observations by showing that chimeras of fluorescent proteins bearing this sequence, namely, CINCCKVL, which become isoprenylated and palmitoylated in cells, may be used to mark endolysosomes while preserving their morphology. Indeed, these chimeric proteins are devoid of the effects derived from overexpression of fluorescent constructs of full-length, active proteins widely used as endolysosomal markers, such as Lamp1 or Rab7, which cause lysosomal enlargement, or RhoB, which induces actin stress fibers.

Protein lipoxidation: Detection strategies and challenges.

Enzymatic and non-enzymatic lipid metabolism can give rise to reactive species that may covalently modify cellular or plasma proteins through a process known as lipoxidation. Under basal conditions, protein lipoxidation can contribute to normal cell homeostasis and participate in signaling or adaptive mechanisms, as exemplified by lipoxidation of Ras proteins or of the cytoskeletal protein vimentin, both of which behave as sensors of electrophilic species. Nevertheless, increased lipoxidation under pathological conditions may lead to deleterious effects on protein structure or aggregation.

Vimentin filament organization and stress sensing depend on its single cysteine residue and zinc binding.

The vimentin filament network plays a key role in cell architecture and signalling, as well as in epithelial-mesenchymal transition. Vimentin C328 is targeted by various oxidative modifications, but its role in vimentin organization is not known. Here we show that C328 is essential for vimentin network reorganization in response to oxidants and electrophiles, and is required for optimal vimentin performance in network expansion, lysosomal distribution and aggresome formation.

An isoprenylation and palmitoylation motif promotes intraluminal vesicle delivery of proteins in cells from distant species.

The C-terminal ends of small GTPases contain hypervariable sequences which may be posttranslationally modified by defined lipid moieties. The diverse structural motifs generated direct proteins towards specific cellular membranes or organelles. However, knowledge on the factors that determine these selective associations is limited.

Modification of cysteine residues by cyclopentenone prostaglandins: interplay with redox regulation of protein function.

Cyclopentenone prostaglandins (cyPG) are endogenous lipid mediators involved in the resolution of inflammation and the regulation of cell proliferation and cellular redox status. Upon exogenous administration they have shown beneficial effects in models of inflammation and tissue injury, as well as potential antitumoral actions, which have raised a considerable interest in their study for the development of therapeutic tools. Due to their electrophilic nature, the best-known mechanism of action of these mediators is the covalent modification of proteins at cysteine residues through Michael addition.

Interactions between autophagic and endo-lysosomal markers in endothelial cells.

Autophagic and endo-lysosomal degradative pathways are essential for cell homeostasis. Availability of reliable tools to interrogate these pathways is critical to unveil their involvement in physiology and pathophysiology. Although several probes have been recently developed to monitor autophagic or lysosomal compartments, their specificity has not been validated through co-localization studies with well-known markers.

15-Deoxy-Δ(12,14)-prostaglandin J2 exerts pro- and anti-inflammatory effects in mesangial cells in a concentration-dependent manner.

Cyclopentenone prostaglandins play a modulatory role in inflammation, in part through their ability to covalently modify key proinflammatory proteins. Using mesangial cells as a cellular model of inflammation we have observed that 15-deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ(2)) exerts a biphasic effect on cell activation by cytokines, with nanomolar concentrations eliciting an amplification of nitric oxide (NO) production and iNOS and COX-2 levels, and concentrations of 5 μM and higher inhibiting proinflammatory gene expression. An analog of 15d-PGJ(2) lacking the cyclopentenone structure (9,10-dihydro-15d-PGJ(2)) showed reduced ability to elicit both types of effects, suggesting that the electrophilic nature of 15d-PGJ(2) is important for its biphasic action.

Proteomic studies on protein modification by cyclopentenone prostaglandins: expanding our view on electrophile actions.

Cyclopentenone prostaglandins (cyPG) are lipid mediators that participate in the mechanisms regulating inflammation and tumorigenesis. cyPG are electrophilic compounds that act mainly through the covalent modification of cellular proteins. The stability of many cyPG-protein adducts makes them suitable for proteomic analysis.