Secukinumab Use in Patients with Moderate to Severe Psoriasis, Psoriatic Arthritis and Ankylosing Spondylitis in Real-World Setting in Europe: Baseline Data from SERENA Study.

INTRODUCTION: Secukinumab, a fully human monoclonal antibody that directly inhibits interleukin-17A, has demonstrated robust efficacy in the treatment of moderate to severe psoriasis (PsO), psoriatic arthritis (PsA) and ankylosing spondylitis (AS), with a rapid onset of action, sustained long-term clinical responses and a consistently favourable safety profile across phase 3 trials. Here, we report the clinical data at enrolment from SERENA, designed to investigate the real-world use of secukinumab across all three indications. METHODS: SERENA is an ongoing, longitudinal, observational study conducted at 438 sites across Europe in patients with moderate to severe plaque PsO, active PsA or active AS. Patients should have received at least 16 weeks of secukinumab treatment before enrolment in the study. RESULTS: Overall 2800 patients were included in the safety set; patients with PsA (N = 541) were older than patients with PsO (N = 1799) and patients with AS (N = 460); patients with PsO had a higher mean body weight than patients with PsA and patients with AS; and patients with PsO and patients with AS were predominantly male. Time since diagnosis was longer in patients with PsO compared with patients with PsA and patients with AS, and about 40% of patients were either current or former smokers. The proportion of obese patients (body mass index ≥ 30 kg/m2) was similar across indications. Patients were treated with secukinumab for a mean duration of 1 year prior to enrolment (range 0.89-1.04). The percentages of patients with prior biologics exposure were 31.5% PsO, 59.7% PsA and 55% AS. The percentages of patients prescribed secukinumab monotherapy were 75% (n = 1349) in PsO, 48.2% (n = 261) in PsA and 48.9% (n = 225) in AS groups. CONCLUSION: Baseline demographics of the study population are consistent with existing literature. This large observational study across all secukinumab indications will provide valuable information on the long-term effectiveness and safety of secukinumab in the real-world setting.

High level expression of a protein precursor for functional studies.

In vitro analyses of type I signal peptidase activities require protein precursors as substrates. Usually, these pre-proteins are expressed in vitro and cleavage of the signal sequence is followed by SDS polyacrylamide gel electrophoresis coupled with autoradiography. Radioactive amino acids have to be incorporated in the expressed protein, since the amount of the in vitro expressed protein is usually very low and processing of the signal peptide cannot be followed by SDS polyacrylamide gel electrophoresis alone. Here we describe a rapid and simple method to express large amounts of a protein precursor in E. coli. We have analyzed the effect of ionophors as well as of azide on the accumulation of expressed protein precursors. Azide blocks the function of SecA and the ionophors dissipate the electrochemical gradient across the cytoplasmic membrane of E. coli. Addition of azide ions resulted in the formation of inclusion bodies, highly enriched with pre-apo-plastocyanine. Plastocyanine is a soluble copper protein, which can be found in the periplasmic space of cyanobacteria as well as in the thylakoid lumen of cyanobacteria and chloroplasts, and the pre-protein contains a cleavable signal sequence at its N-terminus. After purification of cyanobacterial preapo-plastocyanine, its signal sequence can be cleaved off by the E. coli signal peptidase, and protein processing was followed on Coomassie stained SDS polyacrylamide gels. We are optimistic that the presented method can be further developed and applied.

Thylakoid membrane reduction affects the photosystem stoichiometry in the cyanobacterium Synechocystis sp. PCC 6803.

Biogenesis of thylakoid membranes in both chloroplasts and cyanobacteria is largely not understood today. The vesicle-inducing protein in plastids 1 (Vipp1) has been suggested to be essential for thylakoid membrane formation in Arabidopsis (Arabidopsis thaliana), as well as in the cyanobacterium Synechocystis sp. PCC 6803, although its exact physiological function remains elusive so far. Here, we report that, upon depletion of Vipp1 in Synechocystis cells, the number of thylakoid layers in individual Synechocystis cells decreased, and that, in particular, the content of photosystem I (PSI) complexes was highly diminished in thylakoids. Furthermore, separation of native photosynthetic complexes indicated that PSI trimers are destabilized and the monomeric species is enriched. Therefore, depletion of thylakoid membranes specifically affects biogenesis and/or stabilization of PSI in cyanobacteria.

Three different DnaK proteins are functionally expressed in the cyanobacterium Synechocystis sp. PCC 6803.

Multiple dnaK genes appear to be common in cyanobacteria; the function of the encoded proteins is, however, still elusive. To characterize the dnaK gene family from the cyanobacterium Synechocystis sp. PCC 6803 in detail, genetic analyses were combined with analyses of the expression and localization patterns of the three encoded proteins. While significant expression of all three genes was found, the results obtained clearly indicate physiological differences of the three proteins in vivo, and DnaK2 seems to have a key function in Synechocystis. Expression of DnaK3 appears also to be as essential as expression of DnaK2, whereas the dnaK1 gene was deleted without resulting in any distorted phenotype. In line with a suggested privileged function, expression of DnaK2 altered most significantly after heat shock.