RNA remodeling by bacterial global regulator CsrA promotes Rho-dependent transcription termination.

RNA-binding protein CsrA is a key regulator of a variety of cellular processes in bacteria, including carbon and stationary phase metabolism, biofilm formation, quorum sensing, and virulence gene expression in pathogens. CsrA binds to bipartite sequence elements at or near the ribosome loading site in messenger RNA (mRNA), most often inhibiting translation initiation. Here we describe an alternative novel mechanism through which CsrA achieves negative regulation. We show that CsrA binding to the upstream portion of the 5' untranslated region of Escherichia coli pgaA mRNA-encoding a polysaccharide adhesin export protein-unfolds a secondary structure that sequesters an entry site for transcription termination factor Rho, resulting in the premature stop of transcription. These findings establish a new paradigm for bacterial gene regulation in which remodeling of the nascent transcript by a regulatory protein promotes Rho-dependent transcription attenuation.

ATP-dependent motor activity of the transcription termination factor Rho from Mycobacterium tuberculosis.

The bacterial transcription termination factor Rho-a ring-shaped molecular motor displaying directional, ATP-dependent RNA helicase/translocase activity-is an interesting therapeutic target. Recently, Rho from Mycobacterium tuberculosis (MtbRho) has been proposed to operate by a mechanism uncoupled from molecular motor action, suggesting that the manner used by Rho to dissociate transcriptional complexes is not conserved throughout the bacterial kingdom. Here, however, we demonstrate that MtbRho is a bona fide molecular motor and directional helicase which requires a catalytic site competent for ATP hydrolysis to disrupt RNA duplexes or transcription elongation complexes. Moreover, we show that idiosyncratic features of the MtbRho enzyme are conferred by a large, hydrophilic insertion in its N-terminal 'RNA binding' domain and by a non-canonical R-loop residue in its C-terminal 'motor' domain. We also show that the 'motor' domain of MtbRho has a low apparent affinity for the Rho inhibitor bicyclomycin, thereby contributing to explain why M. tuberculosis is resistant to this drug. Overall, our findings support that, in spite of adjustments of the Rho motor to specific traits of its hosting bacterium, the basic principles of Rho action are conserved across species and could thus constitute pertinent screening criteria in high-throughput searches of new Rho inhibitors.

Oral prolonged release beclomethasone dipropionate and prednisone in the treatment of active ulcerative colitis: results from a double-blind, randomized, parallel group study.

OBJECTIVES: Double-blind study comparing efficacy and safety of the topically acting corticosteroid beclomethasone dipropionate (BDP) to prednisone (PD) in patients with active, mild-to-moderate ulcerative colitis (UC). METHODS: Overall, 282 patients were randomized to receive BDP-prolonged release tablets 5 mg once daily for 4 weeks and then every other day for an additional 4 weeks or oral PD 40 mg once daily for the initial 2 weeks tapered of 10 mg every 2 weeks during the 8-week study period. Efficacy end point was the non-inferiority of BDP vs. PD in terms of Disease Activity Index (DAI) score <3 or reduction by at least 3 points for patients with a baseline DAI ≥7 at week 4. Safety end point was the proportion of patients with steroid-related adverse events (AEs) and cortisol <150 nmol/l at week 4. RESULTS: DAI response rates at week 4 were 64.6% and 66.2% with BDP and PD, respectively, demonstrating non-inferiority of BDP vs. PD (delta: -1.56; 95% confidence interval (CI) -13.00-9.88, P=0.78). Patients with steroid-related AEs and cortisol <150 nmol/l at week 4 were 38.7% in the BDP group and 46.9% in the PD group (P=0.17 between groups). No safety signals were observed in both the groups. CONCLUSIONS: BDP was non-inferior to PD in the treatment of active UC, with a good safety profile in both the groups.

Real-world Effectiveness and Safety of Risankizumab in Patients with Moderate to Severe Multirefractory Crohn's Disease: A Belgian Multicentric Cohort Study.

BACKGROUND: As real-world data on risankizumab in patients with moderate to severe Crohn's disease (CD) are scarce, we evaluated its effectiveness and safety in multirefractory Belgian patients. METHODS: Data from consecutive adult CD patients who started risankizumab before April 2023 were retrospectively collected at 6 Belgian centers. Clinical remission and response were defined using the 2-component patient-reported outcome. Endoscopic response was defined as a decrease in baseline Simple Endoscopic Score with ≥50%. Both effectiveness end points were evaluated at week 24 and/or 52, while surgery-free survival and safety were assessed throughout follow-up. RESULTS: A total of 69 patients (56.5% female, median age 37.2 years, 85.5% exposed to ≥4 different advanced therapies and 98.6% to ustekinumab, 14 with an ostomy) were included. At week 24, 61.8% (34 of 55) and 18.2% (10 of 55) of patients without an ostomy achieved steroid-free clinical response and remission, respectively. At week 52, these numbers were 58.2% (32 of 55) and 27.3% (15 of 55), respectively. Endoscopic data were available in 32 patients, of whom 50.0% (16 of 32) reached endoscopic response within the first 52 weeks. Results in patients with an ostomy were similar (steroid-free clinical response and remission, 42.9% and 14.3%, respectively). During a median follow-up of 68.3 weeks, 18.8% (13 of 69) of patients discontinued risankizumab, and 20.3% (14 of 69) of patients underwent CD-related intestinal resections. The estimated surgery-free survival at week 52 was 75.2%. No new safety issues were observed. CONCLUSIONS: In this real-world cohort of multirefractory CD patients, risankizumab was effective in inducing both clinical remission and endoscopic response. Risankizumab was well tolerated with no safety issues.

In this real-world study of multirefractory Crohn's disease patients, risankizumab was effective, with 58.2% and 27.3% achieving steroid-free clinical response and remission, respectively, at week 52. Surgery-free survival at week 52 was 75.2%, and no new safety concerns arose.

Phyletic distribution and conservation of the bacterial transcription termination factor Rho.

Transcription termination factor Rho is a ring-shaped, ATP-dependent molecular motor that targets hundreds of transcription units in Escherichia coli. Interest in Rho was renewed recently on the realization that this essential factor is involved in multiple interactions and cellular processes that protect the E. coli genome and regulate its expression on a global scale. Yet it is currently unknown if (and how) Rho-dependent mechanisms are conserved throughout the bacterial kingdom. Here, we mined public databases to assess the distribution, expression and structural conservation of Rho across bacterial phyla. We found that rho is present in more than 90 % of sequenced bacterial genomes, although Cyanobacteria, Mollicutes and a fraction of Firmicutes are totally devoid of rho. Genomes lacking rho tend to be small and AT-rich and often belong to species with parasitic/symbiotic lifestyles (such as Mollicutes). By contrast, large GC-rich genomes, such as those of Actinobacteria, often contain rho duplicates and/or encode Rho proteins that bear insertion domains of unknown function(s). Notwithstanding, most Rho sequences across taxa contain canonical RNA-binding and ATP hydrolysis signature motifs, a feature suggestive of largely conserved mechanism(s) of action. Mutations that impair binding of bicyclomycin are present in ~5 % of rho sequences, implying that species from diverse ecosystems have developed resistance against this natural antibiotic. Altogether, these findings assert that Rho function is widespread among bacteria and suggest that it plays a particularly relevant role in the expression of complex genomes and/or bacterial adaptation to changing environments.

Efficacy of interferon-based antiviral therapy in patients with chronic hepatitis C infected with genotype 5: a meta-analysis of two large prospective clinical trials.

The characteristics and response rate to pegylated interferon and ribavirin (PEG-INF + RBV) of patients with chronic hepatitis C infected with genotype 5 are poorly documented. A meta-analysis of two large phase III/IV prospective randomized clinical trials conducted in Belgium in patients with chronic hepatitis C (n = 1,073 patients) was performed in order to compare the response to antiviral therapy of hepatitis C virus (HCV) genotype 5 with that of other HCV genotypes. A subset of HCV-1 infected patients selected from within the study database were selected to match the HCV-5 sample for known prognostic factors. In Belgium HCV-5 is responsible for a significant minority of cases of chronic hepatitis C CHC (4.5%) and is characterized by a more advanced age (58.4 years), a high frequency of cirrhosis (27.7%), a specific mode of HCV acquisition, and a particular geographic origin (66.7% of patients from West Flanders). The primary comparative analysis showed that response to treatment with PEG-INF + RBV of HCV-5 is similar to HCV-1 and lower compared to HCV-2/3. The analysis of the matched patient subgroup demonstrates that the HCV-5 "intrinsic sensitivity" to PEG-IFN + RBV therapy is identical to HCV-1, with a sustained virological response of 55% in both groups. In contrast to previous publications, this meta-analysis suggests that HCV-5 response to treatment is closer to HCV-1 than to HCV-2/3 and suggests that in Belgium HCV-5 infection should be treated with the same antiviral regimen as HCV-1.

Beclomethasone dipropionate in microscopic colitis: Results of an exploratory open-label multicentre study (COLCO).

Background: Budesonide has been proven to be an effective treatment for microscopic colitis (MC). However, the two current commercially available preparations are released in the ileum. Beclomethasone dipropionate (Clipper®) is a synthetic corticosteroid with topical colonic release. Objective: This study aimed to explore whether an open-label treatment with beclomethasone dipropionate is an effective treatment for MC. Methods: Prospectively collected data of 30 patients from six centres were retrospectively analysed. All patients had a confirmed diagnosis of idiopathic MC (lymphocytic and collagenous colitis) and were symptomatic (i.e. ≥ 21 loose stools over a seven-day period). Treatment consisted of 10 mg beclomethasone daily for four weeks, followed by 5 mg daily for another four weeks. The primary end point was the proportion of patients in remission (i.e. a mean of < 3 stools/day and a mean of <1 watery stool per day) after an eight-week treatment period. Secondary end points were the proportion of patients responding to therapy at weeks 4 and 8, remission at weeks 4 and 12 and relapse at week 12. Reported adverse events were collected. Results: Overall, at week 8, remission was achieved in 70%, and 77% of patients were responding to treatment. After four weeks of treatment, 80% were responding, and 67% were in remission. Four weeks after stopping treatment, 60% were still in remission. Conclusion: This open-label study suggests that an eight-week course of beclomethasone could be a promising and relatively safe treatment for MC. A randomised controlled study is warranted.

Early Mucosal Healing Predicts Favorable Outcomes in Patients With Moderate to Severe Ulcerative Colitis Treated With Golimumab: Data From the Real-life BE-SMART Cohort.

Background: Golimumab (GOL) is registered for moderate to severely active ulcerative colitis (UC). Data on the use of GOL in daily clinical practice are limited. Currently, it is unclear which factors are predictive of a favorable outcome. The goals of this study were to evaluate the mid-term outcome of GOL (week 26) in patients with moderate to severe UC and to determine predictors of favorable outcome. Methods: Patients included in the SMART study (NCT02155335) were evaluated for their mid-term outcome. Demographic data, disease characteristics, and medical history were recorded retrospectively. Data on disease activity based on total Mayo score, previous and concomitant medication, GOL dosing, mucosal healing (Mayo 0 or 1), adverse events (colectomy, hospitalization), and biomarkers (C-reactive protein, fecal calprotectin, hemoglobin, and albumin) were collected at baseline and weeks 2, 6, 14, 26, and 52. GOL was dosed at 200 and 100 mg at weeks 0 and 2, respectively, and 50 mg (<80 kg body weight) or 100 mg (≥80 kg body weight) every 4 weeks thereafter. The primary end point was steroid-free GOL continuation at week 26. Results: From the 91 evaluable patients (42% female; median age, 42 years; median disease duration, 5 years), 4% were active smokers, 25% had extensive colitis, and 38% had an endoscopic Mayo score of 3 at baseline. The median (interquartile range [IQR]) baseline Mayo score was 9 (8-10). Although 75% of patients had previously failed immunomodulators (IMMs), the majority (87%) were anti-tumor necrosis factor (TNF) naïve. GOL was started in combination with IMM in 40% and steroids in 64%. The median (IQR) duration of GOL therapy during follow-up was 35.7 (11.4-105.7) weeks. Twenty-six weeks after GOL induction, 37 patients (41%) were steroid-free and still on GOL, of whom 8 (21.6%) required GOL dose optimization. Short-term mucosal healing (STMH) at week 14 was evaluated in 60% of the patients. Considering the whole cohort, only 40% achieved STMH. No predictors could be retained of short-term treatment outcome. In multivariate analysis, STMH was predictive of steroid-free GOL continuation at week 26 (odds ratio [OR], 5.56; 95% confidence interval [CI], 1.90-16.29; P = 0.002) and week 52 (OR, 9.38; 95% CI, 2.68-32.84; P < 0.001). In patients continuing GOL after week 14, STMH was predictive of intervention-free survival (OR, 2.05; 95% CI, 1.09-3.86; P = 0.026) and discontinuation-free survival (OR, 3.47; 95% CI, 1.58-7.58; P = 0.002). During follow-up, 78% needed an intervention, 68% discontinued GOL, and 3 patients needed a colectomy. Conclusions: Real-life data confirm the moderate effectiveness of GOL on the mid-term in active UC, but therapeutic interventions are frequently needed. Short-term mucosal healing predicts a favorable outcome. 10.1093/ibd/izy219_video1izy219.video15798038438001.

Preference for a prefilled syringe or an auto-injection device for delivering golimumab in patients with moderate-to-severe ulcerative colitis: a randomized crossover study.

PURPOSE: Simponi® (golimumab, MSD) is a fully human monoclonal antibody against tumor necrosis factor alpha administered subcutaneously using an autoinjector or a prefilled syringe. This study examined preference for administration of golimumab by autoinjector or prefilled syringe in patients with moderate-to-severe ulcerative colitis (UC). PATIENTS AND METHODS: This was a multicenter, open-label, randomized crossover trial (EudraCT no 2014-000656-29). Patients with moderate-to-severe UC were randomized 1:1 to receive 2 subcutaneous injections of 50 mg golimumab with the autoinjector followed by 2 injections of 50 mg with the prefilled syringe or the same 4 injections administered in the opposite order. Patients assessed preference, ease of use, and discomfort immediately after the injections and 2 weeks later. RESULTS: Ninety-one patients were included (median age=42.7 years [range, 19.7-93.7]; 58% male). The autoinjector was preferred by 76.9% of patients immediately after injections and by 71.4% 2 weeks later. The autoinjector was more often considered extremely easy or easy to use (94.5%) than the prefilled syringe (73.6%). Moderate discomfort or worse was reported by more patients when using the prefilled syringe (20.9%) than when using the autoinjector (5.5%), and severe discomfort or discomfort preventing injection of future doses was reported by 8.8% for the pre-filled syringe but not at all when using the autoinjector. A favorable or extremely favorable overall impression was reported by 89.0% for the autoinjector and 72.5% for the prefilled syringe. CONCLUSION: Most patients with moderate-to-severe UC preferred to self-administer golimumab with the autoinjector over a prefilled syringe.

Characteristics of patients with hepatitis B virus and hepatitis C virus dual infection in a Western European country: Comparison with monoinfected patients.

The epidemiology of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections is continuously evolving. Updated data on dual HBV and HCV infection are still needed. AIMS: To assess the main characteristics of patients with HBV and HCV dual infection, to compare these with those of patients infected with either HBV or HCV and, among patients with dual infection, to assess fibrosis according to HCV replication. METHODS: Data of 23 patients with dual infection were compared to data from 92 age and sex-matched HBV or HCV monoinfected patients. RESULTS: Patients with dual infection were more often immigrants from Africa or Asia than HCV or HBV patients (52% vs. 20% and 22%, respectively, P=0.01). Intravenous drug use was the route of transmission in 22% of patients with dual infection, which was less frequent than in HCV patients (41%) but more frequent than in HBV patients (0%). Extensive fibrosis or cirrhosis was as frequent among dual-infected patients as among those with HCV or chronic hepatitis B infection (19% vs. 29% vs. 14%, respectively, P=0.4), even when fibrosis stage was reported considering the duration of infection. In dual-infected patients, the prevalence of extensive fibrosis or cirrhosis was similar in patients with and without detectable HCV RNA (18% vs. 20%). CONCLUSIONS: Patients with HBV and HCV dual infection were more often immigrants from Africa or Asia and had similar fibrosis stages than HCV or HBV monoinfected patients. In patients with dual infection, extensive fibrosis or cirrhosis was not associated with HCV replication.

Belgian experience with direct acting antivirals in people who inject drugs.

BACKGROUND AND AIM: Hepatitis C viral infection (HCV) has become a curable disease due to the development of direct acting antivirals (DAA). The WHO has set a target to eliminate HCV completely. Therefore, people who inject drugs (PWID) also need to be treated. In this study, we compared the real-life uptake and outcome of DAA treatment for HCV in PWID and non-PWID. METHODS: We performed a nation-wide, retrospective cohort study in 15 hospitals. All patients who were treated with simeprevir-sofosbuvir, daclatasvir-sofosbuvir, or ombitasvir/paritaprevir ritonavir-dasabuvir between December 2013 and November 2015 were included. RESULTS: The study population consisted of 579 patients: 115 PWID (19.9%) and 464 non-PWID (80.1%). Of the PWID 18 were active PWID (15.6%), 35 still received opiate substitution therapy (OST) (30.4%) and 62 were former PWID without OST (53.9%). PWID were more infected with genotype 1a and 3 (p=0.001). There were equal rates of side-effects (44.7% vs. 46.6%; p=0.847), similar rates of treatment completion (95.7% vs 98.1%; p=0.244) and SVR (93.0% vs 94.8%; p=0.430) between PWID and non-PWID, respectively. CONCLUSION: PWID, especially active users, are underserved for DAA treatment in real life in Belgium. Reimbursement criteria based on fibrosis stage make it difficult to treat PWID. Treatment adherence is similar in PWID and the general population, even in patients with active abuse. DAA were safe and effective in PWID despite the higher prevalence of difficult-to-treat genotypes. Based on these data more efforts to treat PWID are needed and policy changes are necessary to reach the WHO targets.

Liver Fibrosis Associated with Iron Accumulation Due to Long-Term Heme-Arginate Treatment in Acute Intermittent Porphyria: A Case Series.

Acute intermittent porphyria (AIP) is an autosomal dominant disorder of heme biosynthesis due to a mutation in the porphobilinogen deaminase gene. The mutation causes a deficiency in the porphobilinogen deaminase enzyme, thereby causing an accumulation of heme precursors (δ-aminolevulinic acid and porphobilinogen). These neurotoxic heme precursors elicit acute neurovisceral attacks, which can be treated with heme-arginate infusions. Some patients require heme-arginate infusions on a regular basis for many years, which ultimately leads to an iron accumulation (increased serum ferritin and iron accumulation in the liver, spleen, and bone marrow on MRI). We report three AIP patients, who developed iron accumulation (with serum ferritin up to 7,850 microgram/liter) due to multiple heme-arginate infusions. We report for the first time that the iron accumulation in these patients was associated with fibrosis on liver histology. CONCLUSION: Regular heme-arginate treatment in AIP does not only lead to increased serum ferritin but may also induce liver fibrosis. This should be taken into account, when weighing the risks and benefits of repeated heme-arginate treatment against the risk and benefits of treating refractory AIP by liver transplantation.

Monitoring RNA unwinding by the transcription termination factor Rho from Mycobacterium tuberculosis.

Transcription termination factor Rho is a ring-shaped, homo-hexamieric RNA translocase that dissociates transcription elongation complexes and transcriptional RNA-DNA duplexes (R-loops) in bacteria. The molecular mechanisms underlying these biological functions have been essentially studied with Rho enzymes from Escherichia coli or close Gram-negative relatives. However, phylo-divergent Rho factors may have distinct properties. Here, we describe methods for the preparation and in vitro characterization (ATPase and helicase activities) of the Rho factor from Mycobacterium tuberculosis, a specimen with uncharacteristic molecular and enzymatic features. These methods set the stage for future studies aimed at better defining the diversity of enzymatic properties of Rho across the bacterial kingdom.

Glycerophospholipid synthesis and functions in Pseudomonas.

The genus Pseudomonas is one of the most heterogeneous groups of eubacteria, presents in all major natural environments and in wide range of associations with plants and animals. The wide distribution of these bacteria is due to the use of specific mechanisms to adapt to environmental modifications. Generally, bacterial adaptation is only considered under the aspect of genes and protein expression, but lipids also play a pivotal role in bacterial functioning and homeostasis. This review resumes the mechanisms and regulations of pseudomonal glycerophospholipid synthesis, and the roles of glycerophospholipids in bacterial metabolism and homeostasis. Recently discovered specific pathways of P. aeruginosa lipid synthesis indicate the lineage dependent mechanisms of fatty acids homeostasis. Pseudomonas glycerophospholipids ensure structure functions and play important roles in bacterial adaptation to environmental modifications. The lipidome of Pseudomonas contains a typical eukaryotic glycerophospholipid--phosphatidylcholine -, which is involved in bacteria-host interactions. The ability of Pseudomonas to exploit eukaryotic lipids shows specific and original strategies developed by these microorganisms to succeed in their infectious process. All compiled data provide the demonstration of the importance of studying the Pseudomonas lipidome to inhibit the infectious potential of these highly versatile germs.

Hepatitis B virus and hepatitis C virus infections in Belgium: similarities and differences in epidemics and initial management.

INTRODUCTION: Nationwide studies comparing patients with hepatitis B and C virus (HBV and HCV) infections are mandatory for assessing changes in epidemiology. AIM: The aim of this study was to compare epidemiological data and initial management of newly diagnosed patients with persistent HBV (HBsAg positive) or HCV (detectable HCV RNA) infection in Belgium. PATIENTS AND METHODS: Data were extracted from two Belgian observational databases. RESULTS: A total of 655 patients (387 HBV and 268 HCV) were included. Compared with HCV patients, HBV patients were younger, more frequently men, more often of Asian or African origin (43 vs. 10%, P<0.0001), and less frequently contaminated by transfusion or intravenous drug use (9 and 6% vs. 34 and 44%, P<0.0001). Viral replication was assessed in 89% of HBV patients. Compared with HCV patients, HBV patients more frequently had normal alanine aminotransferase (ALT) levels (65 vs. 29%, P<0.0001), less frequently underwent liver biopsy (29 vs. 67%, P<0.0001), and were less often considered for antiviral therapy (25 vs. 54%, P<0.0001). When taking only HBV patients with detectable viral replication into consideration, results remained unchanged. During the multivariate analysis, ALT was a major factor for performing liver biopsy or considering antiviral therapy in both groups. CONCLUSION: HBV and HCV screening policies should be targeted toward immigrants and intravenous drug users, respectively. Guidelines recommending systematic search for viral replication should be reinforced in HBV patients. HBV patients less frequently underwent liver biopsy and were less often considered for antiviral therapy compared with HCV patients. Despite the lack of sensitivity and specificity, ALT remains a pivotal decision-making tool for liver biopsy and antiviral therapy in both infections.

Chronic oesophagitis dissecans: a case report.

Chronic oesophagitis dissecans is an often unrecognised cause of chronic dysphagia. It usually occurs in otherwise healthy patients and was first described as We report the case of a patient with chronic dysphagia due to chronic oesophagitis dissecans.