Inhibition of peptide aggregation by means of enzymatic phosphorylation

As is the case in numerous natural processes, enzymatic phosphorylation can be used in the laboratory to influence the conformational populations of proteins. In nature, this information is used for signal transduction or energy transfer, but has also been shown to play an important role in many diseases like tauopathies or diabetes. With the goal of determining the effect of phosphorylation on amyloid fibril formation, we designed a model peptide which combines structural characteristics of α-helical coiled-coils and β-sheets in one sequence. This peptide undergoes a conformational transition from soluble structures into insoluble amyloid fibrils over time and under physiological conditions and contains a recognition motif for PKA (cAMP- dependent protein kinase) that enables enzymatic phosphorylation. We have analyzed the pathway of amyloid formation and the influence of enzymatic phosphorylation on the different states along the conformational transition from random-coil to β-sheet-rich oligomers to protofilaments and on to insoluble amyloid fibrils, and we found a remarkable directing effect from β -sheet-rich structures to unfolded structures in the initial growth phase, in which small oligomers and protofilaments prevail if the peptide is phosphorylated

The anti-staphylococcal lipolanthines are ribosomally synthesized lipopeptides

International audienceThe potent antibacterial lanthipeptide microvionin, isolated from a culture of Microbacterium arborescens, exhibits a new triamino-dicarboxylic acid moiety, termed avionin, and an unprecedented N-terminal guanidino fatty acid. We identified the corresponding biosynthetic gene cluster and reconstituted central steps of avionin biosynthesis in vitro. Genome mining and isolation of nocavionin from Nocardia terpenica revealed a widespread distribution of this lanthipeptide class, termed lipolanthines, which may be useful as future antimicrobial drugs

Health Assessment Questionnaire-Disability Index (HAQ-DI) use in modelling disease progression in diffuse cutaneous systemic sclerosis: an analysis from the EUSTAR database

BACKGROUND: Patients with diffuse cutaneous systemic sclerosis (dcSSc) have a poor prognosis. The importance of monitoring subjective measures of functioning and disability, such as the Health Assessment Questionnaire-Disability Index (HAQ-DI), is important as dcSSc is rated by patients as worse than diabetes or hemodialysis for quality of life impairment. This European Scleroderma Trials and Research (EUSTAR) database analysis was undertaken to examine the importance of impaired functionality in dcSSc prognosis. The primary objectives were to identify predictors of death and HAQ-DI score progression over 1 year. HAQ-DI score, major advanced organ involvement, and death rate were also used to develop a comprehensive model to predict lifetime dcSSc progression. METHODS: This was an observational, longitudinal study in patients with dcSSc registered in EUSTAR. Death and HAQ-DI scores were, respectively, analyzed by Cox regression and linear regression analyses in relation to baseline covariates. A microsimulation Markov model was developed to estimate/predict natural progression of dcSSc over a patient's lifetime. RESULTS: The analysis included dcSSc patients with (N = 690) and without (N = 4132) HAQ-DI score assessments from the EUSTAR database. Baseline HAQ-DI score, corticosteroid treatment, and major advanced organ involvement were predictive of death on multivariable analysis; a 1-point increase in baseline HAQ-DI score multiplied the risk of death by 2.7 (p <  0.001) and multiple advanced major organ involvement multiplied the risk of death by 2.8 (p <  0.05). Multivariable analysis showed that baseline modified Rodnan Skin Score (mRSS) and baseline HAQ-DI score were associated with HAQ-DI score progression at 1 year (p <  0.05), but there was no association between baseline organ involvement and HAQ-DI score progression at 1 year. HAQ-DI score, major advanced organ involvement, and death were successfully used to model long-term disease progression in dcSSc. CONCLUSIONS: HAQ-DI score and major advanced organ involvement were comparable predictors of mortality risk in dcSSc. Baseline mRSS and baseline HAQ-DI score were predictive of HAQ-DI score progression at 1 year, indicating a correlation between these endpoints in monitoring disease progression. It is hoped that this EUSTAR analysis may change physician perception about the importance of the HAQ-DI score in dcSSc

Significant weight loss in systemic sclerosis: a study from the EULAR Scleroderma Trials and Research (EUSTAR) database

Gastrointestinal (GI) involvement is almost universal in patients with systemic sclerosis (SSc) and is associated with significant disease-related morbidity and mortality.1 The entire GI tract can be involved and other disease features (eg, low mood, terminal organ failure and functional hand impairment) can result in significant nutritional impairment. Severe GI involvement has been reported to occur in ~10% of patients with SSc and often occurs early in the course of the disease.2 However, identification of patients at high risk of clinically significant weight loss is extremely challenging, including from the high prevalence of GI symptoms in patients with SSc. Therefore, there is a need to understand high-risk patients including potentially modifiable risk factors, with a view to early intervention strategies. Against this background, the aim of this study was to examine potential clinical risk factors of significant weight loss in patients with SSc. We performed an analysis of patients with SSc enrolled in the multinational, longitudinal European League Against Rheumatism (EULAR) Scleroderma Trials and Research (EUSTAR) database. In our study, we defined significant weight loss as 4.5 kg and/or least 5% of their body weight at 5 months onwards.3 Patients with a recorded second visit after 3 months and before 12 months were included in the analysis. We adopted a pragmatic approach (relevant to clinical practice) in