Yet Another Similarity between Mitochondrial and Bacterial Ribosomal Small Subunit Biogenesis Obtained by Structural Characterization of RbfA from S. aureus

Ribosome biogenesis is a complex and highly accurate conservative process of ribosomal subunit maturation followed by association. Subunit maturation comprises sequential stages of ribosomal RNA and proteins' folding, modification and binding, with the involvement of numerous RNAses, helicases, GTPases, chaperones, RNA, protein-modifying enzymes, and assembly factors. One such assembly factor involved in bacterial 30S subunit maturation is ribosomal binding factor A (RbfA). In this study, we present the crystal (determined at 2.2 Å resolution) and NMR structures of RbfA as well as the 2.9 Å resolution cryo-EM reconstruction of the 30S-RbfA complex from Staphylococcus aureus (S. aureus). Additionally, we show that the manner of RbfA action on the small ribosomal subunit during its maturation is shared between bacteria and mitochondria. The obtained results clarify the function of RbfA in the 30S maturation process and its role in ribosome functioning in general. Furthermore, given that S. aureus is a serious human pathogen, this study provides an additional prospect to develop antimicrobials targeting bacterial pathogens.

Y98 Mutation Leads to the Loss of RsfS Anti-Association Activity in Staphylococcus aureus

Ribosomal silencing factor S (RsfS) is a conserved protein that plays a role in the mechanisms of ribosome shutdown and cell survival during starvation. Recent studies demonstrated the involvement of RsfS in the biogenesis of the large ribosomal subunit. RsfS binds to the uL14 ribosomal protein on the large ribosomal subunit and prevents its association with the small subunit. Here, we estimated the contribution of RsfS amino acid side chains at the interface between RsfS and uL14 to RsfS anti-association function in Staphylococcus aureus through in vitro experiments: centrifugation in sucrose gradient profiles and an S. aureus cell-free system assay. The detected critical Y98 amino acid on the RsfS surface might become a new potential target for pharmacological drug development and treatment of S. aureus infections.

[ORF19.2286 Gene: Isolation and Purification of Deoxyhypusine Hydroxylase from the Human Pathogenic Yeast Candida albicans]

Candida albicans (C. albicans) is a fungal pathogen that causes infections of the wet body surfaces and the blood in immunocompromised patients or individuals with imbalanced microflora. Since the cases of clinically meaningful candidosis are on the rise, efficient С. albicans therapy is in a high demand. Informed drug design requires well-characterized С. albicans targets, including these aimed at disrupting its post-translational modifications. C. albicans ORF19.2286 gene encodes an ortholog of human deoxyhypusine hydroxylase (DOHH). Here, this ORF was cloned from the SC5314 strain and re-expressed in Escherichia coli as sGB1 - CaDOHH construct with 6xHis tag on the N-terminus of the fusion protein, then purified, and GB1-tag was removed with Tobacco etch virus (TEV) protease. Several amino acid sequence differences between C. albicans and animal DOHHs were noted, and are useful for a selection of the binding sites for antimicrobials in CaDOHH. We present the protocol for the heterologous expression and purification of C. albicans DOHH, which is suitable for further crystallization.

AB0291 RITUXIMAB MAY DELAY THE MOVEMENT OF RHEUMATOID ARTHRITIS PATIENTS ON CARDIORENAL CONTINUUM: RESULTS FROM A PROSPECTIVE OBSERVATIONAL SINGLE-CENTRE COHORT STUDY

Background:

Similarities in risk factors, initial stages, progression and final stage of both atherosclerotic cardiovascular disease (ACVD) and chronic kidney disease (CKD) allowed formulating a concept of cardiorenal continuum.1ACVD and CKD remain the main causes of mortality in rheumatoid arthritis (RA) patients.2,3

Objectives:

To evaluate the effects of rituximab (RTM) therapy on cardiorenal continuum of RA patients.

Methods:

Biologics-naïve RA patients (n=92; age 49.5±9.9) were followed up for 72 months after commencing and continuing RTM therapy (1–10 standard courses) compared with 50 control RA patients (age 49.2±9.8). All control and 63% of RTM patients received methotrexate or leflunomide.

Results:

There were no baseline differences between two groups – Table. At year 6, RTM patients have fewer incidences of hypertension, anxiety/depression, atherosclerosis and diastolic dysfunction than controls. RTM decreased prevalence of albuminuria and CKD.

Table.

Cardiorenal continuum of rheumatoid arthritis patients (%)

FeaturesRituximab groupControl grouppRTM–C1 year n=923 years n=476 years n=311 yearn=503 years n=266 years n=16Risk factorsHypertension52.238.325.8p6–1=0.02250.038.550.0p6=0.032Dyslipidaemia44.636.238.748.046.250.0>0.05Pre-diabetes41.336.241.944.034.656.3>0.05Metabolic syndrome12.06.43.210.07.712.5>0.05Diabetes mellitus3.2002.000>0.05Anxiety/depression78.341.5p3–1=0.00535.3p6–1<0.00176.073.168.8p3=0.009p6=0.008Initial stages (asymptomatic organ damage)Atherosclerosis34.821.312.9p6–1=0.04536.034.637.5p6=0.02Left ventricular hypertrophy8.74.308.07.70>0.05Diastolic dysfunction57.638.322.6p6–1=0.01856.050.056.3p6=0.04Albuminuria19.600p6–1=0.03812.006.3>0.05Kidney impairment6.52.106.000>0.05ProgressionAngina6.5004.000>0.05Chronic kidney disease26.18.59.7p6–1=0.04212.000>0.05End stageMyocardial infarction000000>0.05Stroke000000>0.05Heart failure4.400000>0.05Acute/chronic renal failure000000>0.05Death000000>0.05

There were no significant differences in frequencies of other risk factors, signs of organ damage and cases of established heart, cerebrovascular and renal diseases/complications.

Conclusion:

RTM may be effective in delay of the movement of RA patients on cardiorenal continuum. The clinical implications of RTM for cardiorenal correlations in RA patients need to be confirmed in large-scale clinical outcome trials.

References:

[1]Sarnak MJ, Levey AS. Cardiovascular disease and chronic renal disease: a new paradigm.Am J Kidney Dis2000;35(4, Suppl. 1):117–31.

[2]Avina-Zubieta JA, Choi HK, Sadatsafarvi M,et al.Risk of cardiovascular mortality in patients with rheumatoid arthritis: a meta-analysis of observational studies.Arthritis Rheum2008;59:1690–7.

[3]Gullick NJ, Scott DL. Co-morbidities in established rheumatoid arthritis.Best Pract Res Clin Rheumatol2011;25:469–83.

Disclosure of Interests:

Ilshat Gaisin Speakers bureau: Boehringer Ingelheim, KRKA, Berlin-Chemie Menarini, Sanofi, Larisa Ivanova Speakers bureau: Bayer, Novartis, KRKA, Nikolay Maximov Speakers bureau: Pfizer, KRKA, Rosa Valeeva: None declared, Dilara Yurk: None declared, Anastasia Vedekhina: None declared, Nuriya Garaeva: None declared, Irina Sabelnikova: None declared

SAT0107 BIOLOGIC THERAPY WITH RITUXIMAB DECREASES PREVALENCE OF ANXIETY AND DEPRESSION IN RHEUMATOID ARTHRITIS PATIENTS

Background:

Evidence suggests rheumatoid arthritis (RA) confers an increased risk of psychological morbidity, particularly anxiety and depression, which may affect the subsequent management and treatment adherence.1,2Few studies have studied psychological factors over time in RA patients.3

Objectives:

To evaluate the prevalence of anxiety and depression in RA patients following rituximab treatment.

Methods:

92 biologics-naïve RA patients [mean (SD) age 49.5 (9.9) years, 78 women; median (IQR) DAS28 5.67 (3.94–8.45); median (IQR) HAQ 1.87 (1.2–3.5)] were followed up for 27 months after commencing and continuing rituximab therapy (1, 2, 3 standard courses). Anxiety and depression, and health-related quality of life (HRQoL) were assessed at baseline, 3, 15 and 27 months using the Hospital Anxiety and Depression Scale (HADS) and the Short Form (SF-36 v.1) Health Survey questionnaire, respectively.

Results:

Median anxiety and depression scores decreased significantly between baseline and 3 months and continued depress over the 27-month period – Table. The prevalence of depression cases decreased twice from baseline to 27 months (p<0.01), as did the prevalence of anxiety (p<0.01). Patients reported poor baseline HRQoL. SF-36 domain scores substantially rose after 15 and 27 months.

Anxiety, depression, and quality of lifeBaseline3 months15 months27 months(n=92)(n=92)(n=53)(n=14)Anxiety cases (HADS-A score ≥8), n (%)72 (78.3)48 (52.2)24 (45.3)*5 (35.7)**Median (IQR) Anxiety score12.6 (10–15)8.2 (5–12)*6.4 (3–10)**5.5 (3–8)***Depression cases (HADS-D score ≥8), n (%)62 (67.4)50 (54.3)19 (35.8)*4 (28.6)**Median (IQR) Depression score9.2 (7.8–9.6)5.6 (3–8)**4.5 (2–7)**3.6 (2–6)***Mean (SD) Mental Health score42.8 (15.2)51.2 (18.3)68.7 (11.2)*72.9 (10.5)**Mean (SD) Physical Function score24.4 (8.3)32.5 (9.8)53.8 (10.5)*54.5 (9.3)*Mean (SD) Social Function score48.2 (15.4)56.8 (25.5)59.8 (18.7)65.9 (9.2)*Mean (SD) General Health score35.8 (11.2)48.7 (10.8)67.8 (8.6)**75.9 (12.6)**

* p<0.05, ** p<0.01, *** p<0.001 differences between baseline and follow-up

Conclusion:

Anxiety and depression levels decrease significantly in RA patients following commencement and continuity of rituximab. B cell-directed therapy for patients with RA helps achieve remission of both anxiety and depression, and improves HRQoL.

References:

[1]McWilliams LA, Goodvin RD, Cox BJ. Depression and anxiety associated with three pain conditions: results from a nationally representative sample.Pain2004;111:77–83.

[2]Garcia-Cebrian A, Gandhi P, Demyttenaere K et al. The association of depression and painful physical symptoms: a review of the European literature.Eur Psychiatry2006;21:379–88.

[3]Overman CL, Bossema ER, van Middendorp H et al. The prospective association between psychological distress and disease activity in rheumatoid arthritis: a multilevel regression analysis.Ann Rheum Dis2012;71:192–7.

Disclosure of Interests:

Ilshat Gaisin Speakers bureau: Boehringer Ingelheim, KRKA, Berlin-Chemie Menarini, Sanofi, Larisa Ivanova Speakers bureau: Bayer, Novartis, KRKA, Nikolay Maximov Speakers bureau: Pfizer, KRKA, Anastasia Vedekhina: None declared, Dilara Yurk: None declared, Nuriya Garaeva: None declared

NMR and crystallographic structural studies of the Elongation factor P from Staphylococcus aureus

Elongation factor P (EF-P) is a translation protein factor that plays an important role in specialized translation of consecutive proline amino acid motifs. EF-P is an essential protein for cell fitness in native environmental conditions. It regulates synthesis of proteins involved in bacterial motility, environmental adaptation and bacterial virulence, thus making EF-P a potential drug target. In the present study, we determined the solution and crystal structure of EF-P from the pathogenic bacteria Staphylococcus aureus at 1.48 Å resolution. The structure can serve as a platform for structure-based drug design of novel antibiotics to combat the growing antibiotic resistance of S. aureus.