TrpM, a Small Protein Modulating Tryptophan Biosynthesis and Morpho-Physiological Differentiation in Streptomyces coelicolor A3(2).

In the model actinomycete Streptomyces coelicolor A3(2), small open reading frames encoding proteins with unknown functions were identified in several amino acid biosynthetic gene operons, such as SCO2038 (trpX) in the tryptophan trpCXBA locus. In this study, the role of the corresponding protein in tryptophan biosynthesis was investigated by combining phenotypic and molecular analyses. The 2038KO mutant strain was characterized by delayed growth, smaller aerial hyphae and reduced production of spores and actinorhodin antibiotic, with respect to the WT strain. The capability of this mutant to grow on minimal medium was rescued by tryptophan and tryptophan precursor (serine and/or indole) supplementation on minimal medium and by gene complementation, revealing the essential role of this protein, here named TrpM, as modulator of tryptophan biosynthesis. His-tag pull-down and bacterial adenylate cyclase-based two hybrid assays revealed TrpM interaction with a putative leucyl-aminopeptidase (PepA), highly conserved component among various Streptomyces spp. In silico analyses showed that PepA is involved in the metabolism of serine, glycine and cysteine through a network including GlyA, CysK and CysM enzymes. Proteomic experiments suggested a TrpM-dependent regulation of metabolic pathways and cellular processes that includes enzymes such as GlyA, which is required for the biosynthesis of tryptophan precursors and key proteins participating in the morpho-physiological differentiation program. Altogether, these findings reveal that TrpM controls tryptophan biosynthesis at the level of direct precursor availability and, therefore, it is able to exert a crucial effect on the morpho-physiological differentiation program in S. coelicolor A3(2).

Elucidating the molecular physiology of lantibiotic NAI-107 production in Microbispora ATCC-PTA-5024.

BACKGROUND: The filamentous actinomycete Microbispora ATCC-PTA-5024 produces the lantibiotic NAI-107, which is an antibiotic peptide effective against multidrug-resistant Gram-positive bacteria. In actinomycetes, antibiotic production is often associated with a physiological differentiation program controlled by a complex regulatory and metabolic network that may be elucidated by the integration of genomic, proteomic and bioinformatic tools. Accordingly, an extensive evaluation of the proteomic changes associated with NAI-107 production was performed on Microbispora ATCC-PTA-5024 by combining two-dimensional difference in gel electrophoresis, mass spectrometry and gene ontology approaches. RESULTS: Microbispora ATCC-PTA-5024 cultivations in a complex medium were characterized by stages of biomass accumulation (A) followed by biomass yield decline (D). NAI-107 production started at 90 h (A stage), reached a maximum at 140 h (D stage) and decreased thereafter. To reveal patterns of differentially represented proteins associated with NAI-107 production onset and maintenance, differential proteomic analyses were carried-out on biomass samples collected: i) before (66 h) and during (90 h) NAI-107 production at A stage; ii) during three time-points (117, 140, and 162 h) at D stage characterized by different profiles of NAI-107 yield accumulation (117 and 140 h) and decrement (162 h). Regulatory, metabolic and unknown-function proteins, were identified and functionally clustered, revealing that nutritional signals, regulatory cascades and primary metabolism shift-down trigger the accumulation of protein components involved in nitrogen and phosphate metabolism, cell wall biosynthesis/maturation, lipid metabolism, osmotic stress response, multi-drug resistance, and NAI-107 transport. The stimulating role on physiological differentiation of a TetR-like regulator, originally identified in this study, was confirmed by the construction of an over-expressing strain. Finally, the possible role of cellular response to membrane stability alterations and of multi-drug resistance ABC transporters as additional self-resistance mechanisms toward the lantibiotic was confirmed by proteomic and confocal microscopy experiments on a Microbispora ATCC-PTA-5024 lantibiotic-null producer strain which was exposed to an externally-added amount of NAI-107 during growth. CONCLUSION: This study provides a net contribution to the elucidation of the regulatory, metabolic and molecular patterns controlling physiological differentiation in Microbispora ATCC-PTA-5024, supporting the relevance of proteomics in revealing protein players of antibiotic biosynthesis in actinomycetes.

Inorganic phosphate is a trigger factor for Microbispora sp. ATCC-PTA-5024 growth and NAI-107 production.

BACKGROUND: NAI-107, produced by the actinomycete Microbispora sp. ATCC-PTA-5024, is a promising lantibiotic active against Gram-positive bacteria and currently in late preclinical-phase. Lantibiotics (lanthionine-containing antibiotics) are ribosomally synthesized and post-translationally modified peptides (RiPPs), encoded by structural genes as precursor peptides. The biosynthesis of biologically active compounds is developmentally controlled and it depends upon a variety of environmental stimuli and conditions. Inorganic phosphate (Pi) usually negatively regulates biologically-active molecule production in Actinomycetes, while it has been reported to have a positive control on lantibiotic production in Firmicutes strains. So far, no information is available concerning the Pi effect on lantibiotic biosynthesis in Actinomycetes. RESULTS: After having developed a suitable defined medium, Pi-limiting conditions were established and confirmed by quantitative analysis of polyphosphate accumulation and of expression of selected Pho regulon genes, involved in the Pi-limitation stress response. Then, the effect of Pi on Microbispora growth and NAI-107 biosynthesis was investigated in a defined medium containing increasing Pi amounts. Altogether, our analyses revealed that phosphate is necessary for growth and positively influences both growth and NAI-107 production up to a concentration of 5 mM. Higher Pi concentrations were not found to further stimulate Microbispora growth and NAI-107 production. CONCLUSION: These results, on one hand, enlarge the knowledge on Microbispora physiology, and, on the other one, could be helpful to develop a robust and economically feasible production process of NAI-107 as a drug for human use.

Targeting IL-6 signalling in early rheumatoid arthritis is followed by Th1 and Th17 suppression and Th2 expansion.

OBJECTIVES: To investigate the in vitro and ex-vivo effect of IL-6 inhibition on the balance between Th1, Th2, Th17 and Treg cells. METHODS: Ten consecutive adult patients with active early rheumatoid arthritis (ERA) and ten healthy volunteers were included in the study. The percentages of Th1, Th2, Th17 and Treg cells were analysed by flow cytometry in the peripheral blood mononuclear cells obtained from controls and from RA patients at the time of first evaluation and just before the third TCZ infusion. The in vitro effect of TCZ on the different subsets of CD4+ T cells and the expression levels of Th1, Th2, Th17 and Treg-related cytokines was also assessed. RESULTS: Treatment with TCZ, both ex vivo and in vitro, resulted in a significant reduction of the percentage of Th1, Th17 and Treg cells with a concomitant significant increase of Th2 cell subsets. The reduction of the different subsets of T lymphocytes was associated with an intense staining with Annexin V, suggesting an apoptotic-related cell reduction. A significant decrease of Th1, Th17 and Treg cytokines and a concomitant increase of IL-4 was also observed after TCZ treatment in PBMC isolated from RA patients. CONCLUSIONS: TCZ could modify the immune imbalance in RA inducing apoptosis of Th1, Th17 and Treg cells and promoting the appearance of a Th2 response.

Remission in early, aggressive rheumatoid arthritis: a multicentre prospective observational Italian study ARPA (Artrite Reumatoide Precoce Aggressiva).

OBJECTIVES: To provide a survey of disease activity in patients treated with standard care in Italian clinical practice. METHODS: This was an observational prospective cohort study in patients with early, aggressive rheumatoid arthritis (RA; duration ≤2 years but ≥6 weeks; DAS28 >3.2) naïve to anti-tumour necrosis factor (TNF) therapy who were treated with disease-modifying anti-rheumatic drugs (DMARDs) and/or biologics according to standard practice at 15 Italian ARPA (Artrite Reumatoide Precoce Aggressiva) centres. Patients were evaluated at baseline and after 6, 12 and 24 months. The primary endpoint was the proportion of patients achieving remission, as defined by disease activity score in 28 joints (DAS28) <2.6, after 1 year. RESULTS: Among the 152 patients enrolled, 92 were evaluable after 1 year and 77 after 2 years for DAS28. At baseline, patients had a mean DAS28 of 6.1±1.0. At 12 months, 62.6% of patients were treated with DMARDs (in monotherapy or in combination), and 37.4% with anti-TNFs (in monotherapy or in association with DMARDs). At 24 months, 35.1% were receiving anti-TNF therapy. The rate of DAS28 remission rates at 12 months and 24 months were 28.3% (95% confidence interval [CI] 19.1-37.5) and 41.6% (95% confidence interval [CI] 30.6-52.6), respectively. CONCLUSIONS: The remission rate was lower at 12 months compared with previous large randomised clinical trials for early, aggressive RA, but significantly improved at 24 months. These results suggest that patients in real-world clinical settings in Italy may experience a delay in receiving the best possible care.

No detection of occult HBV-DNA in patients with various rheumatic diseases treated with anti-TNF agents: a two-year prospective study.

OBJECTIVES: The widespread use of tumour necrosis factor (TNF)-targeted therapies in patients with rheumatic, digestive and dermatologic diseases has been associated with reports of reactivation of HBV replication and ensuing hepatitis flares both in asymptomatic HBsAg carriers and in subjects with occult HBV infection. The aim of our work was to investigate in a two-year prospective study the potential for HBV reactivation in patients with inflammatory joint diseases undergoing anti-TNF treatment from a southern Mediterranean area. METHODS: Fifty-seven consecutive outpatients attending the Academic Unit of Rheumatology at the University of Palermo (12 with rheumatoid arthritis, 17 with psoriatic arthritis and 28 with ankylosing spondylitis) were enrolled in the study. HBV-DNA was tested by a standard quantitative assay in HBsAg-positive subjects and by an ad hoc highly sensitive PCR in HBsAg-negative patients performed at baseline and then every six months on the anti-TNF agent. RESULTS: Occult HBV-DNA was never detected in the 54 HBsAg negative subjects, regardless of their anti HBs/HBc status. All HBsAg positive patients, who were started on prophylactic lamivudine, remained HBV-DNA undetectable throughout the anti-TNF treatment. CONCLUSIONS: Even in an area of previously high HBV endemicity, where occult HBV infection is likely to have a high prevalence, treatment of rheumatological patients with anti-TNF drugs is safe in terms of its potential to reactivate HBV. Prophylaxis with lamivudine is sufficient to prevent reactivation in HBsAg carriers.

Obesity and reduction of the response rate to anti-tumor necrosis factor α in rheumatoid arthritis: an approach to a personalized medicine.

OBJECTIVE: Obesity is a mild, long-lasting inflammatory disease and, as such, could increase the inflammatory burden of rheumatoid arthritis (RA). The study aim was to determine whether obesity represents a risk factor for a poor remission rate in RA patients requiring anti-tumor necrosis factor α (anti-TNFα) therapy for progressive and active disease despite treatment with methotrexate or other disease-modifying antirheumatic drugs. METHODS: Patients were identified from 15 outpatient clinics of university hospitals and hospitals in Italy taking part in the Gruppo Italiano di Studio sulle Early Arthritis network. Disease Activity Score in 28 joints (DAS28), body mass index (BMI; categorized as <25, 25-30, and >30 kg/m(2) ), acute-phase reactants, IgM rheumatoid factor, and anti-cyclic citrullinated peptide antibody values were collected. DAS28 remission was defined as a score of <2.6 lasting for at least 3 months. RESULTS: Six hundred forty-one outpatients with longstanding RA receiving anti-TNFα blockers (adalimumab, n = 260; etanercept, n = 227; infliximab, n = 154), recruited from 2006-2009 and monitored for at least 12 months, were analyzed. The mean ± SD DAS28 at baseline was 5.6 ± 1.4. A BMI of >30 kg/m(2) was recorded in 66 (10.3%) of 641 RA patients. After 12 months of anti-TNFα treatment, a DAS28 of <2.6 was noted in 15.2% of the obese subjects, in 30.4% of the patients with a BMI of 25-30 kg/m(2) , and in 32.9% of the patients with a BMI of <25 kg/m(2) (P = 0.01). The lowest percentage of remission, which was statistically significant versus adalimumab and etanercept (P = 0.003), was observed with infliximab. CONCLUSION: Obesity represents a risk factor for a poor remission rate in patients with longstanding RA treated with anti-TNFα agents. A personalized treatment plan might be a possible solution.

Are Toll-like receptors and decoy receptors involved in the immunopathogenesis of systemic lupus erythematosus and lupus-like syndromes?

In this paper we focus our attention on the role of two families of receptors, Toll-like receptors (TLR) and decoy receptors (DcR) involved in the generation of systemic lupus erythematosus (SLE) and lupus-like syndromes in human and mouse models. To date, these molecules were described in several autoimmune disorders such as rheumatoid arthritis, antiphospholipids syndrome, bowel inflammation, and SLE. Here, we summarize the findings of recent investigations on TLR and DcR and their role in the immunopathogenesis of the SLE.

Successful intravenous immunoglobulin treatment for steroid-resistant eosinophilic enteritis in a patient with systemic lupus erythematosus.

Eosinophilic gastroenteritis is a rare condition of unknown etiology characterized by eosinophilic infiltration of the bowel. Corticosteroids are the mainstay of EG therapy. Although rare, steroid-resistant EG could be a life-threatening condition with tissue destructive evolution. Associations of eosinophilic gastroenteritis with systemic lupus erythematosus have rarely been reported. In this report we describe a case of successful IVIG treatment in a patient with systemic lupus erythematosus and steroid-refractory eosinophilic gastroenteritis.

A Th1 but not a Th17 response is present in the gastrointestinal involvement of Behçet's disease.

OBJECTIVES: Behçet's disease has been historically classified as a Th1 disease. The recently described IL-17/IL-23 pathway seems to play an important role in many inflammatory diseases and in the intestinal abnormalities of AS and CD. The aim of the present study was to evaluate the IL-17/IL-23 axis in parallel with Th1 and IL-27 response in the intestine of patients with BD and gastrointestinal abnormalities. METHODS: Quantitative TaqMan reverse transcriptase-polymerase chain reaction (RT-PCR) was utilised for all determinations on ileal biopsy specimens obtained from BD, AS and CD patients. The serum levels of Th1 and Th17 cytokines were evaluated by enzyme-linked immunosorbent assay. RESULTS: A Th1 but not a Th17 response is present in the gastrointestinal involvement of Behçet's disease. CONCLUSIONS: Although BD shares clinical manifestations with both CD and AS, the immunologic abnormalities seen in the intestine are quite different, indicating that other immune mechanisms should be taken into account.

Over-expression of paneth cell-derived anti-microbial peptides in the gut of patients with ankylosing spondylitis and subclinical intestinal inflammation.

OBJECTIVES: Subclinical gut inflammation has been demonstrated in patients with AS. Altered expression of paneth cell (PC) anti-microbial peptides have been reported in the inflamed ileum of patients with Crohn's disease (CD). Here, we investigated the expression of PC-derived peptides in subclinical gut inflammation in AS. METHODS: Multiple adjacent mucosal biopsies from terminal ileum were obtained from 25 patients with AS, 30 CD and 15 healthy controls (HCs). Expression of human α-defensin 5 (HD-5), phospholipase A2 (PLA2), lysozyme and SOX-9 molecules was assessed by quantitative Taqman RT-PCR on mucosal samples. Immunohistochemistry with anti-human HD-5 antibody and genotyping of relevant NOD2 mutations was also performed. RESULTS: HD-5, PLA2 and lysozyme transcript levels were strongly increased in AS and CD with similar degrees of intestinal inflammation when compared with normal controls. Immunohistochemical evaluation showed a normal number of PCs in both AS patients with chronic gut inflammation and CD patients with less-inflamed ileal samples. Conversely, CD patients with higher degree of gut inflammation had a reduced number of PCs and low expression levels of HD-5. CONCLUSION: In this study, we provide evidence that over-expression of PC-derived anti-microbial peptides occurs in the ileum of AS patients with subclinical gut inflammation, likely representing an important early alteration of the mucosal innate immune component and intestinal host defence in AS.

Two heterologously expressed Planobispora rosea proteins cooperatively induce Streptomyces lividans thiostrepton uptake and storage from the extracellular medium.

BACKGROUND: A bacterial artificial chromosomal library of Planobispora rosea, a genetically intractable actinomycete strain, was constructed using Escherichia coli-Streptomyces artificial chromosome (ESAC) and screened for the presence of genes known to be involved in the biosynthesis of antibiotics. RESULTS: One clone with a 40 kb insert showed antimicrobial activity against Gram positive bacteria. Insert sequence analysis and subcloning experiments revealed that the bioactivity was due to a 3.5 kb DNA fragment containing two open reading frames. These orfs encode two proteins with high similarity to a putative membrane protein of Streptomyces coelicolor and to the nogalamycin resistance protein SnorO of Streptomyces nogalater, respectively. The role of these two Orfs is unknown in Planobispora. Disruption and complementation experiments revealed that both proteins are necessary for the antibacterial activity and chemical analysis demonstrated that the antibiotic activity was due to thiostrepton, antibiotic used as recombinant clone selection marker. CONCLUSION: Two Planobispora rosea orfs are responsible for increasing intracellular amounts and storage of thiostrepton in Streptomyces lividans.

Phenotype and functional changes of Vgamma9/Vdelta2 T lymphocytes in Behçet's disease and the effect of infliximab on Vgamma9/Vdelta2 T cell expansion, activation and cytotoxicity.

INTRODUCTION: Infliximab is a chimeric monoclonal antibody against tumor necrosis factor alpha (TNF-alpha) that has been introduced recently for Behçet's disease (BD) patients who were resistant to standard treatment. The aim of this study was to analyse the functional changes of Vgamma9/Vdelta2 T lymphocytes in both active and inactive disease and the effect of infliximab on Vgamma9/Vdelta2 T cell expansion, activation and cytotoxicity. METHODS: We investigated 1) cell expansion, 2) expression of TNFRII receptor, 3) perforin and gamma interferon (IFN) content, 4) release of granzyme A (GrA) and 5) phenotype changes, in vitro and in vivo, in Vgamma9/Vdelta2 T lymphocytes by means of fluorescence-activated cell sorter analysis of lymphocyte cultures from patients with active and inactive BD and healthy subjects. RESULTS: Cell expansion, expression of TNFRII, perforin and gamma IFN content and release of granzyme A were significantly higher in active patients. In vitro and ex vivo treatment with infliximab resulted in a significant reduction of all parameters together with changes in the phenotype of Vgamma9/Vdelta2 T cells. CONCLUSIONS: All together these data indicate that infliximab is capable of interfering with Vgamma9/Vdelta2 T cell function in BD and although cell culture models cannot reliably predict all potential effects of the drug in vivo, our results present the possibility that this drug may find use in a range of immunological disorders, characterized by dysregulated cell-mediated immunity.

A 2-year comparative open label randomized study of efficacy and safety of etanercept and infliximab in patients with ankylosing spondylitis.

The signs and symptoms of ankylosing spondylitis (AS) respond inadequately to nonsteroidal antiinflammatory drugs, corticosteroids, and disease modifying antirheumatic drugs in quite a number of patients. Tumor necrosis factor inhibitors have demonstrated to be of value in reducing AS disease activity in clinical trials. The efficacy and safety of both etanercept and infliximab in patients with ankylosing spondylitis were compared in a 2-year open label randomised study. Our results are consistent with a significant more rapid clinical improvement in the infliximab treated group. Treatment with both etanercept and infliximab at the end of the study was effective, safe, and well tolerated.

Expression in Streptomyces lividans of Nonomuraea genes cloned in an artificial chromosome.

A bacterial artificial chromosomal library of Nonomuraea sp. ATCC39727 was constructed using Escherichia coli-Streptomyces artificial chromosome (ESAC) and screened for the presence of dbv genes known to be involved in the biosynthesis of the glycopeptide A40926. dbv genes were cloned as two large, partially overlapping, fragments and transferred into the host Streptomyces lividans, thus generating strains S. lividansColon, two colonsNmESAC50 and S. lividansColon, two colonsNmESAC57. The heterologous expression of Nonomuraea genes in S. lividans was successfully demonstrated by using combined RT-PCR and proteomic approaches. MALDI-TOF analysis revealed that a Nonomuraea ABC transporter is expressed as two isoforms in S. lividans. Moreover, its expression may not require a Nonomuraea positive regulator at all, as it is present at similar levels in both clones even though S. lividansColon, two colonsNmESAC57 lacks regulatory genes. Considered together, these results show that S. lividans expresses Nonomuraea genes from their own promoters and support the idea that S. lividans can be a good host for genetic analysis of Nonomuraea.