Myeloid conditional deletion and transgenic models reveal a threshold for the neutrophil survival factor Serpinb1

Serpinb1 is an inhibitor of neutrophil granule serine proteases cathepsin G, proteinase-3 and elastase. One of its core physiological functions is to protect neutrophils from granule protease-mediated cell death. Mice lacking Serpinb1a (Sb1a-/-), its mouse ortholog, have reduced bone marrow neutrophil numbers due to cell death mediated by cathepsin G and the mice show increased susceptibility to lung infections. Here, we show that conditional deletion of Serpinb1a using the Lyz2-cre and Cebpa-cre knock-in mice effectively leads to recombination-mediated deletion in neutrophils but protein-null neutrophils were only obtained using the latter recombinase-expressing strain. Absence of Serpinb1a protein in neutrophils caused neutropenia and increased granule permeabilization-induced cell death. We then generated transgenic mice expressing human Serpinb1 in neutrophils under the human MRP8 (S100A8) promoter. Serpinb1a expression levels in founder lines correlated positively with increased neutrophil survival when crossed with Sb1a-/- mice, which had their defective neutrophil phenotype rescued in the higher expressing transgenic line. Using new conditional and transgenic mouse models, our study demonstrates the presence of a relatively low Serpinb1a protein threshold in neutrophils that is required for sustained survival. These models will also be helpful in delineating recently described functions of Serpinb1 in metabolism and cancer

Salinomycin and Other Ionophores as a New Class of Antimalarial Drugs with Transmission-Blocking Activity

The drug target profile proposed by the Medicines for Malaria Venture for a malaria elimination/eradication policy focuses on molecules active on both asexual and sexual stages of Plasmodium, thus with both curative and transmission-blocking activities. The aim of the present work was to investigate whether the class of monovalent ionophores, which includes drugs used in veterinary medicine and that were recently proposed as human anticancer agents, meets these requirements. The activity of salinomycin, monensin, and nigericin on Plasmodium falciparum asexual and sexual erythrocytic stages and on the development of the Plasmodium berghei and P. falciparum mosquito stages is reported here. Gametocytogenesis of the P. falciparum strain 3D7 was induced in vitro, and gametocytes at stage II and III or stage IV and V of development were treated for different lengths of time with the ionophores and their viability measured with the parasite lactate dehydrogenase (pLDH) assay. The monovalent ionophores efficiently killed both asexual parasites and gametocytes with a nanomolar 50% inhibitory concentration (IC50). Salinomycin showed a fast speed of kill compared to that of standard drugs, and the potency was higher on stage IV and V than on stage II and III gametocytes. The ionophores inhibited ookinete development and subsequent oocyst formation in the mosquito midgut, confirming their transmission-blocking activity. Potential toxicity due to hemolysis was excluded, since only infected and not normal erythrocytes were damaged by ionophores. Our data strongly support the downstream exploration of monovalent ionophores for repositioning as new antimalarial and transmission-blocking leads

In Vivo and In Vitro Activities and ADME-Tox Profile of a Quinolizidine-Modified 4-Aminoquinoline: A Potent Anti-P. falciparum and Anti-P. vivax Blood-Stage Antimalarial.

Natural products are a prolific source for the identification of new biologically active compounds. In the present work, we studied the in vitro and in vivo antimalarial efficacy and ADME-Tox profile of a molecular hybrid (AM1) between 4-aminoquinoline and a quinolizidine moiety derived from lupinine (Lupinus luteus). The aim was to find a compound endowed with the target product profile-1 (TCP-1: molecules that clear asexual blood-stage parasitaemia), proposed by the Medicine for Malaria Venture to accomplish the goal of malaria elimination/eradication. AM1 displayed a very attractive profile in terms of both in vitro and in vivo activity. By using standard in vitro antimalarial assays, AM1 showed low nanomolar inhibitory activity against chloroquine-sensitive and resistant P. falciparum strains (range IC50 16-53 nM), matched with a high potency against P. vivax field isolates (Mean IC50 29 nM). Low toxicity and additivity with artemisinin derivatives were also demonstrated in vitro. High in vivo oral efficacy was observed in both P.berghei and P. yoelii mouse models with IC50 values comparable or better than those of chloroquine. The metabolic stability in different species and the pharmacokinetic profile in the mouse model makes AM1 a compound worth further investigation as a potential novel schizonticidal agent

CSF β-amyloid predicts prognosis in patients with multiple sclerosis

Background: The importance of predicting disease progression in multiple sclerosis (MS) has increasingly been recognised, hence reliable biomarkers are needed. Objectives: To investigate the prognostic role of cerebrospinal fluid (CSF) Amyloid beta1-42 (A) levels by the determination of a cut-off value to classify patients in slow and fast progressors. To evaluate possible association with white (WM) and grey matter (GM) damage at early disease stages. Methods: Sixty patients were recruited and followed-up for three to five years. Patients underwent clinical assessment, CSF analysis to determine Aβ levels, and brain MRI (at baseline and after 1 year). T1-weighted volumes were calculated. T2-weighted scans were used to quantify WM lesion loads. Results: Lower CSF Aβ levels were observed in patients with a worse follow-up EDSS (r=−0.65, p0.05). Conclusions: Low CSF Aβ levels may represent a predictive biomarker of disease progression in MS

Dative constructions in Romance and beyond

This book offers a comprehensive account of dative structures across languages –with an important, though not exclusive, focus on the Romance family. As is well-known, datives play a central role in a variety of structures, ranging from ditransitive constructions to cliticization of indirect objects and differentially marked direct objects, and including also psychological predicates, possessor or causative constructions, among many others. As interest in all these topics has increased significantly over the past three decades, this volume provides an overdue update on the state of the art. Accordingly, the chapters in this volume account for both widely discussed patterns of dative constructions as well as those that are relatively unknown

Dative constructions in Romance and beyond

This book offers a comprehensive account of dative structures across languages –with an important, though not exclusive, focus on the Romance family. As is well-known, datives play a central role in a variety of structures, ranging from ditransitive constructions to cliticization of indirect objects and differentially marked direct objects, and including also psychological predicates, possessor or causative constructions, among many others. As interest in all these topics has increased significantly over the past three decades, this volume provides an overdue update on the state of the art. Accordingly, the chapters in this volume account for both widely discussed patterns of dative constructions as well as those that are relatively unknown

Dative constructions in Romance and beyond

This book offers a comprehensive account of dative structures across languages –with an important, though not exclusive, focus on the Romance family. As is well-known, datives play a central role in a variety of structures, ranging from ditransitive constructions to cliticization of indirect objects and differentially marked direct objects, and including also psychological predicates, possessor or causative constructions, among many others. As interest in all these topics has increased significantly over the past three decades, this volume provides an overdue update on the state of the art. Accordingly, the chapters in this volume account for both widely discussed patterns of dative constructions as well as those that are relatively unknown

Dative constructions in Romance and beyond

This book offers a comprehensive account of dative structures across languages –with an important, though not exclusive, focus on the Romance family. As is well-known, datives play a central role in a variety of structures, ranging from ditransitive constructions to cliticization of indirect objects and differentially marked direct objects, and including also psychological predicates, possessor or causative constructions, among many others. As interest in all these topics has increased significantly over the past three decades, this volume provides an overdue update on the state of the art. Accordingly, the chapters in this volume account for both widely discussed patterns of dative constructions as well as those that are relatively unknown

Dative constructions in Romance and beyond

This book offers a comprehensive account of dative structures across languages –with an important, though not exclusive, focus on the Romance family. As is well-known, datives play a central role in a variety of structures, ranging from ditransitive constructions to cliticization of indirect objects and differentially marked direct objects, and including also psychological predicates, possessor or causative constructions, among many others. As interest in all these topics has increased significantly over the past three decades, this volume provides an overdue update on the state of the art. Accordingly, the chapters in this volume account for both widely discussed patterns of dative constructions as well as those that are relatively unknown