Functional characterization of twelve natural PROS1 mutations associated with anticoagulant protein S deficiency

Background The molecular mechanisms by which PROS1 mutations result in protein S deficiency are still unknown for many of the mutations, particularly for those that result in a premature termination codon. The aim of this study was to analyze the functional relevance on mRNA and protein expression of 12 natural PROS1 mutations associated with protein S deficiency. Design and Methods Five mutations were nonsense, three were small frameshift deletions, one was c.258,259AG>GT at the 3' end of exon 3, one was p.M640T and the last two were c.-7C>G and p.L15H, found in double heterozygosis as [c.-7C>G;44T>A].The apparently neutral variant p.R233K was also analyzed. PROS1 cDNA was assessed by reverse transcriptase polymerase chain reaction of platelet mRNA. Expression of mutant proteins was determined by site-directed mutagenesis and analyses of transiently transfected PROS1 mutants in COS-7 cells. Results Only cDNA from the normal allele was observed from the five nonsense mutations, the frameshift deletion c.1731delT and from c.258,259AG>GT. Both the normal and the mutated alleles were observed from [c.-7C>G;44T>Aj, c.187,188delTG and p.M640T Transient expression analyses of PROS1 mutants whose mRNA was normally expressed revealed greatly reduced secretion of p.L15H and c.1272delA, mild secretion values of p.M640T and normal secretion levels of c.7C>G and, as expected, p.R233K. Conclusions Whereas the main cause of quantitative protein S deficiency associated with missense mutations is defective synthesis, stability or secretion of the mutated protein, the main mechanism for the deficiency associated with mutations that generate a premature termination codon is not the synthesis of a truncated protein, but the exclusion of the mutated allele, probably by nonsense-mediated mRNA decay

Clinical characteristics and outcome of Spanish patients with ANCA-associated vasculitides Impact of the vasculitis type, ANCA specificity, and treatment on mortality and morbidity

The aim of this study was to describe the clinical characteristics of ANCA-associated vasculitides (AAV) at presentation, in a wide cohort of Spanish patients, and to analyze the impact of the vasculitis type, ANCA specificity, prognostic factors, and treatments administered at diagnosis, in the outcome. A total of 450 patients diagnosed between January 1990 and January 2014 in 20 Hospitals from Spain were included. Altogether, 40.9% had granulomatosis with polyangiitis (GPA), 37.1% microscopic polyangiitis (MPA), and 22% eosinophilic granulomatosis with polyangiitis (EGPA). The mean age at diagnosis was 55.6±17.3 years, patients with MPA being significantly older (P<0.001). Fever, arthralgia, weight loss, respiratory, and ear-nose-throat (ENT) symptoms, were the most common at disease onset. ANCAs tested positive in 86.4% of cases: 36.2% C-ANCA-PR3 and 50.2% P-ANCA-MPO. P-ANCA-MPO was significantly associated with an increased risk for renal disease (OR 2.6, P<0.001) and alveolar hemorrhage (OR 2, P=0.010), while C-ANCA-PR3 was significantly associated with an increased risk for ENT (OR 3.4, P<0.001) and ocular involvement (OR 2.3, P=0.002). All patients received corticosteroids (CS) and 74.9% cyclophosphamide (CYC). The median follow-up was 82 months (IQR 100.4). Over this period 39.9% of patients suffered bacterial infections and 14.6% opportunistic infections, both being most prevalent in patients with highcumulated doses of CYC and CS (P<0.001). Relapses were recorded in 36.4% of cases with a mean rate of 2.5±2.3, and were more frequent in patients with C-ANCA-PR3 (P=0.012). The initial disease severity was significantly associated with mortality but not with the occurrence of relapses. One hundred twenty-nine (28.7%) patients (74 MPA, 41 GPA, 14 EGPA) died. The mean survival was 58 months (IQR 105) and was significantly lower for patients with MPA (P<0.001). Factors independently related to death were renal involvement (P=0.010), cardiac failure (P=0.029) and age over 65 years old (P<0.001) at disease onset, and bacterial infections (P<0.001). An improved outcome with significant decrease in mortality and treatment-related morbidity was observed in patients diagnosed after 2000, and was related to the implementation of less toxic regimens adapted to the disease activity and stage, and a drastic reduction in the cumulated CYC and CS dose

Functional characterization of twelve natural PROS1 mutations associated with anticoagulant protein S deficiency

[Background]: The molecular mechanisms by which PROS1 mutations result in protein S deficiency are still unknown for many of the mutations, particularly for those that result in a premature termination codon. The aim of this study was to analyze the functional relevance on mRNA and protein expression of 12 natural PROS1 mutations associated with protein S deficiency.[Design and methods]: Five mutations were nonsense, three were small frameshift deletions, one was c.258,259AG>GT at the 3' end of exon 3, one was p.M640T and the last two were c.-7C>G and p.L15H, found in double heterozygosis as [c.-7C>G;44T>A]. The apparently neutral variant p.R233K was also analyzed. PROS1 cDNA was assessed by reverse transcriptase polymerase chain reaction of platelet mRNA. Expression of mutant proteins was determined by site-directed mutagenesis and analyses of transiently transfected PROS1 mutants in COS-7 cells.[Results]: Only cDNA from the normal allele was observed from the five nonsense mutations, the frameshift deletion c.1731delT and from c.258,259AG>GT. Both the normal and the mutated alleles were observed from [c.-7C>G;44T>A], c.187,188delTG and p.M640T. Transient expression analyses of PROS1 mutants whose mRNA was normally expressed revealed greatly reduced secretion of p.L15H and c.1272delA, mild secretion values of p.M640T and normal secretion levels of c.-7C>G and, as expected, p.R233K.[Conclusions]: Whereas the main cause of quantitative protein S deficiency associated with missense mutations is defective synthesis, stability or secretion of the mutated protein, the main mechanism for the deficiency associated with mutations that generate a premature termination codon is not the synthesis of a truncated protein, but the exclusion of the mutated allele, probably by nonsense-mediated mRNA decay.Funding: we acknowledge grants ISCIII 01/1468, ISCIII network C03/07 and ISCIII PI051149, from the Instituto de Salud Carlos III; SAF 2001-1059 and SAF2004-07539, from the Spanish Ministry of Education and Science; and grant 2002-PIR-00333 from the AGAUR, Generalitat de Catalunya. BH is the recipient of a grant from the Institut d’Investigació Biomèdica de Bellvitge (IDIBELL06/IDB-001).Peer reviewe

CD69 plays a beneficial role in ischemic stroke potentially via the modulation of leukocyte recruitment and secondary microthrombosis

Trabajo presentado en el Brain & BrainPET, celebrado en Canadá, del 27 al 30 de junio de 2015[Objectives] Expression of CD69 is a hallmark of lymphocyte activation and the majority of research on CD69 has focused on its effects on the immune system. Several lines of evidence support that inflammatory and immune responses are involved in stroke brain damage. The aim of this study was to examine whether CD69 plays a role in stroke outcome and to investigate the underlying mechanisms.[Methods] Cerebral ischemia was produced by 45-min intraluminal middle cerebral artery occlusion (tMCAo) followed by reperfusion in male CD69 KO (n=56) and Wt (n=68) mice. In addition, permanent distal MCAo (pMCAo) was induced in male CD69 KO (n=28) and Wt (n=41) mice and in Rag2-/- CD69-/- (n=27) and Rag2-/- CD69+/+ (n=31) mice. Neurological impairment was assessed and brain infarct and edema volume were measured using MRI (T2 maps). Flow cytometry was used to measure changes in immune cell populations in the brain, spleen, cervical lymph nodes (CLNs) and the blood. PCR was performed to measure changes in inflammatory gene expression in the brain. Circulating von Willebrand factor (vWF) levels (ELISA) and function (Collagen Binding Assay) were studied in plasma, and fibrin(ogen) deposition was also studied in cerebral blood vessels (Western Blot). In other mice, we performed the tail-bleeding test. Animal work was carried out in compliance with Spanish law and with approval of the Ethics Committee (CEEA) of the University of Barcelona. Results: CD69 KO mice had a significantly larger infarct volume compared to Wt mice at 24 and 72h after tMCAo (P<0.05). Also, CD69 deficiency increased infarct volume 24h after pMCAo (P<0.05). Following tMCAo, CD69 KO mice were more functionally impaired using a neurological score and tape test than the Wt mice. 96h after tMCAo, CD69 KO mice had a greater percentage of T cells (CD45hi CD3+) in the CLNs, spleen and brain compared to WT mice and less B cells (CD45+ CD45R+) in the CLNs. There was also a greater number of neutrophils (CD11b+ Ly6G+) in the brain. To test whether the absence of CD69 in lymphocytes was responsible for the observed effects, we carried out pMCAo in lymphocyte deficient Rag2-/- mice. Rag2-/- mice showed smaller infarct volumes than the Wt mice (P<0.001) and CD69 deficiency in Rag2-/- mice increased infarct volume (P<0.001) demonstrating that the absence of CD69 in cells other than lymphocytes was playing a role. In addition to lymphocytes, CD69 is expressed in platelets, which led us to hypothesize that CD69 deficiency might affect thrombosis. Preliminary findings in the tail-bleeding test showed a trend for less total bleeding time and less rebleeds in the CD69 KO mice compared to the Wt mice. In the plasma, the concentration and activity of vWF was higher 6h after pMCAo in CD69 KO mice compared to Wt mice (P<0.05). In cerebral blood vessels, CD69 deficiency enhanced vWF expression and fibrin(ogen) deposition after ischemia.[Conclusions] Our results suggest that CD69 may play a beneficial role in cerebral ischemia by regulating leukocyte recruitment and secondary local microthrombosis.Supported by the Spanish Ministry of Economy (SAF2011-30492).Peer Reviewe

Functional characterization of twelve natural PROS1 mutations associated with anticoagulant protein S deficiency

Background: The molecular mechanisms by which PROS1 mutations result in protein S deficiency are still unknown for many of the mutations, particularly for those that result in a premature termination codon. The aim of this study was to analyze the functional relevance on mRNA and protein expression of 12 natural PROS1 mutations associated with protein S deficiency. Design and Methods: Five mutations were nonsense, three were small frameshift deletions, one was c.258,259AG>GT at the 3' end of exon 3, one was p.M640T and the last two were c.-7C>G and p.L15H, found in double heterozygosis as [c.-7C>G;44T>A].The apparently neutral variant p.R233K was also analyzed. PROS1 cDNA was assessed by reverse transcriptase polymerase chain reaction of platelet mRNA. Expression of mutant proteins was determined by site-directed mutagenesis and analyses of transiently transfected PROS1 mutants in COS-7 cells. Results: Only cDNA from the normal allele was observed from the five nonsense mutations, the frameshift deletion c.1731delT and from c.258,259AG>GT. Both the normal and the mutated alleles were observed from [c.-7C>G;44T>Aj, c.187,188delTG and p.M640T Transient expression analyses of PROS1 mutants whose mRNA was normally expressed revealed greatly reduced secretion of p.L15H and c.1272delA, mild secretion values of p.M640T and normal secretion levels of c.7C>G and, as expected, p.R233K. Conclusions: Whereas the main cause of quantitative protein S deficiency associated with missense mutations is defective synthesis, stability or secretion of the mutated protein, the main mechanism for the deficiency associated with mutations that generate a premature termination codon is not the synthesis of a truncated protein, but the exclusion of the mutated allele, probably by nonsense-mediated mRNA decay

Functional characterization of twelve natural PROS1 mutations associated with anticoagulant protein S deficiency

Background The molecular mechanisms by which PROS1 mutations result in protein S deficiency are still unknown for many of the mutations, particularly for those that result in a premature termination codon. The aim of this study was to analyze the functional relevance on mRNA and protein expression of 12 natural PROS1 mutations associated with protein S deficiency. Design and Methods Five mutations were nonsense, three were small frameshift deletions, one was c.258,259AG>GT at the 3' end of exon 3, one was p.M640T and the last two were c.-7C>G and p.L15H, found in double heterozygosis as [c.-7C>G;44T>A].The apparently neutral variant p.R233K was also analyzed. PROS1 cDNA was assessed by reverse transcriptase polymerase chain reaction of platelet mRNA. Expression of mutant proteins was determined by site-directed mutagenesis and analyses of transiently transfected PROS1 mutants in COS-7 cells. Results Only cDNA from the normal allele was observed from the five nonsense mutations, the frameshift deletion c.1731delT and from c.258,259AG>GT. Both the normal and the mutated alleles were observed from [c.-7C>G;44T>Aj, c.187,188delTG and p.M640T Transient expression analyses of PROS1 mutants whose mRNA was normally expressed revealed greatly reduced secretion of p.L15H and c.1272delA, mild secretion values of p.M640T and normal secretion levels of c.7C>G and, as expected, p.R233K. Conclusions Whereas the main cause of quantitative protein S deficiency associated with missense mutations is defective synthesis, stability or secretion of the mutated protein, the main mechanism for the deficiency associated with mutations that generate a premature termination codon is not the synthesis of a truncated protein, but the exclusion of the mutated allele, probably by nonsense-mediated mRNA decay

Functional characterization of twelve natural PROS1 mutations associated with anticoagulant protein S deficiency

Background The molecular mechanisms by which PROS1 mutations result in protein S deficiency are still unknown for many of the mutations, particularly for those that result in a premature termination codon. The aim of this study was to analyze the functional relevance on mRNA and protein expression of 12 natural PROS1 mutations associated with protein S deficiency. Design and Methods Five mutations were nonsense, three were small frameshift deletions, one was c.258,259AG>GT at the 3' end of exon 3, one was p.M640T and the last two were c.-7C>G and p.L15H, found in double heterozygosis as [c.-7C>G;44T>A].The apparently neutral variant p.R233K was also analyzed. PROS1 cDNA was assessed by reverse transcriptase polymerase chain reaction of platelet mRNA. Expression of mutant proteins was determined by site-directed mutagenesis and analyses of transiently transfected PROS1 mutants in COS-7 cells. Results Only cDNA from the normal allele was observed from the five nonsense mutations, the frameshift deletion c.1731delT and from c.258,259AG>GT. Both the normal and the mutated alleles were observed from [c.-7C>G;44T>Aj, c.187,188delTG and p.M640T Transient expression analyses of PROS1 mutants whose mRNA was normally expressed revealed greatly reduced secretion of p.L15H and c.1272delA, mild secretion values of p.M640T and normal secretion levels of c.7C>G and, as expected, p.R233K. Conclusions Whereas the main cause of quantitative protein S deficiency associated with missense mutations is defective synthesis, stability or secretion of the mutated protein, the main mechanism for the deficiency associated with mutations that generate a premature termination codon is not the synthesis of a truncated protein, but the exclusion of the mutated allele, probably by nonsense-mediated mRNA decay