Mycobacterium tuberculosis prokaryotic ubiquitin-like protein-deconjugating enzyme is an unusual aspartate amidase.

Deamidase of Pup (Dop), the prokaryotic ubiquitin-like protein (Pup)-deconjugating enzyme, is critical for the full virulence of Mycobacterium tuberculosis and is unique to bacteria, providing an ideal target for the development of selective chemotherapies. We used a combination of genetics and chemical biology to characterize the mechanism of depupylation. We identified an aspartate as a potential nucleophile in the active site of Dop, suggesting a novel protease activity to target for inhibitor development.

Indexed left atrial volume predicts the recurrence of non-valvular atrial fibrillation after successful cardioversion.

AIMS: Atrial fibrillation (AFib) induces remodelling of the left atrium (LA). Indexed LA volume (iLAV) as more accurate measure of LA size has not been evaluated as predictor of recurrence of AFib after cardioversion. METHODS AND RESULTS: We identified 411 adults (mean age 64.1 ± 11.4 years, 34.5% women) who underwent successful cardioversion and with no history of other atrial arrhythmia, stroke, congenital heart disease, valvular dysfunction, surgery, thyroid dysfunction, acute or chronic inflammatory disease, and pacemaker. All echocardiographic data were retrieved from the laboratory database. iLAV was measured off-line using Simpson's method. Clinical characteristics and recurrence of clinical AFib were determined by review of medical records. Patients with scheduled follow-up of at least 6 months were included. About 250 patients (60.8%) developed AFib recurrence after a median (25th-75th percentile) follow-up of 345.0 (210.0-540.0) days. Patients with AFib recurrence had significantly greater iLAV than patients without AFib recurrence (39.7 ± 8.4 vs. 31.4 ± 4.6, P < 0.001). Each mL/m(2) increase in iLAV was associated with a 30% increased risk of AFib recurrence [odds ratio (OR) 1.30, confidence interval (CI) 1.23-1.38, P < 0.001]. In a multivariable model, each mL/m(2) increase in iLAV was independently associated with a 21% increase in the risk of AFib recurrence (OR 1.21, CI 1.11-1.30, P < 0.001). The areas under receiver operating characteristic curves, generated to compare LA diameter and iLAV as predictors of AFib recurrence, were 0.59 ± 0.3 and 0.85 ± 0.2, respectively (P < 0.001). CONCLUSION: The present study is the first to show that larger iLAV before cardioversion, as a more accurate measure of LA remodelling than LA diameter, is strongly and independently associated with higher risks of AFib recurrence.

Implantable electrical devices for prevention of sudden cardiac death: data on implant rates from a 'real world' regional registry.

AIMS: International and national consensus guidelines define appropriate indications for implantable cardioverter-defibrillators (ICDs), but the variability in implant rates in 'real world' clinical practice is still unknown. METHODS AND RESULTS: In Emilia-Romagna, an Italian region with around 4.3 million inhabitants, a web-based registry was instituted to collect data for all ICDs implanted. Between January 2006 and December 2008, data from all consecutive patients resident in this region who underwent first implant of an ICD or a biventricular ICD were collected and standardized, considering each regional area (i.e. each of the nine provinces). The overall number of implanted ICDs had an increase in years 2007 and 2008, with a relative increase in comparison to 2006, by 14 and 48% respectively, reaching an average value of 16.2 per 10,000 inhabitants in 2008. Most of the increase was due to a rise in ICDs for primary prevention. The ratio between the implant rates of the provinces with the highest and the lowest implant rates, respectively, was around 2 in 2008. CONCLUSION: Implant rates for ICDs, considering both primary and secondary prevention of sudden death, show up to two-fold variations even in a geographical region where the general level of health care is advanced and well appreciated by the population. The lack of a common strategy for sudden death prevention, approved by both physicians and institutional regional authorities, together with some degree of variability in translating guidelines into clinical practice, were identified as the main factors explaining the heterogeneity in ICD implant rates.

A case of primary cardiac angiosarcoma: extensive right atrial wall reconstruction with autologous pericardium.

Primary cardiac angiosarcoma is a rare and aggressive tumor. Diagnosis is usually late because of the rarity of the lesion and the nonspecific clinical symptoms. We report the case of a 48-year-old man affected by angiosarcoma of the right atrium who presented with subacute cardiac tamponade. Extensive resection of the atrial wall infiltrated by the tumor, followed by autologous pericardial free atrial wall reconstruction, was successfully carried out. In spite of the optimal early outcome, the patient died 15 months later because of multiple osteal metastases.

DUB-resistant ubiquitin to survey ubiquitination switches in mammalian cells.

The ubiquitin-modification status of proteins in cells is highly dynamic and maintained by specific ligation machineries (E3 ligases) that tag proteins with ubiquitin or by deubiquitinating enzymes (DUBs) that remove the ubiquitin tag. The development of tools that offset this balance is critical in characterizing signaling pathways that utilize such ubiquitination switches. Herein, we generated a DUB-resistant ubiquitin mutant that is recalcitrant to cleavage by various families of DUBs both in vitro and in mammalian cells. As a proof-of-principle experiment, ectopic expression of the uncleavable ubiquitin stabilized monoubiquitinated PCNA in the absence of DNA damage and also revealed a defect in the clearance of the DNA damage response at unprotected telomeres. Importantly, a proteomic survey using the uncleavable ubiquitin identified ubiquitinated substrates, validating the DUB-resistant ubiquitin expression system as a valuable tool for interrogating cell signaling pathways.

ALIX is a Lys63-specific polyubiquitin binding protein that functions in retrovirus budding.

The diversity of ubiquitin (Ub)-dependent signaling is attributed to the ability of this small protein to form different types of covalently linked polyUb chains and to the existence of Ub binding proteins that interpret this molecular syntax. We used affinity capture/mass spectrometry to identify ALIX, a component of the ESCRT pathway, as a Ub binding protein. We report that the V domain of ALIX binds directly and selectively to K63-linked polyUb chains, exhibiting a strong preference for chains composed of more than three Ub. Sequence analysis identified two potential Ub binding sites on a single α-helical surface within the coiled-coil region of the V domain. Mutation of these putative Ub binding sites inhibited polyUb binding to the isolated V domain in vitro and impaired budding of lentiviruses. These data reveal an important role for K63 polyUb binding by ALIX in retroviral release.

[Dronedarone: a real innovation or a mere second-best choice? How to find the way among guidelines, regulatory agencies and daily clinical practice]. / Dronedarone: una reale innovazione o solo una valida seconda scelta? Come districarsi tra linee guida, agenzie regolatorie e pratica clinica quotidiana.

Dronedarone is the antiarrhythmic drug with the most complete and wide literature preceding its marketing. Most of these studies showed a good efficacy along with an excellent risk profile, especially in low- and medium-risk patients. Recently, updates of European, American and even Italian guidelines gave dronedarone its own spot into the antiarrhythmic armamentarium, recommending its use both for rhythm control and rate control in non-permanent atrial fibrillation. In Italy, however, dronedarone prescription is still possible only when amiodarone is not tolerated, making dronedarone a mere second choice of its older "relative". Moreover, patients taking dronedarone must undergo a strict alanine aminotransferase and bilirubin follow-up, which usefulness in predicting drug-induced liver damage (probably idiosyncratic in nature and therefore unpredictable) is far from demonstrated. The aim of this review is to sum up actual evidences on dronedarone, describe how these evidences had been differently transposed by panel of experts and drug agencies into guidelines and recommendations, and define the current difficulties encountered by the cardiologist in the correct use of this new antiarrhythmic agent in clinical practice.

Delta12-Prostaglandin J2 inhibits the ubiquitin hydrolase UCH-L1 and elicits ubiquitin-protein aggregation without proteasome inhibition.

To investigate molecular mechanisms linking inflammation with neurodegeneration, we treated neuronal cultures with prostaglandins (PGs), which are mediators of inflammation. PGA1, D2, J2, and Delta12-PGJ2, but not PGE2, reduced the viability and raised the levels of ubiquitinated proteins in the neuronal cells. PGJ2 and its metabolite, Delta12-PGJ2, were the most potent of the four neurotoxic PGs tested in inducing both effects. To address the mechanism by which these agents lead to the accumulation of ubiquitinated proteins, we tested their effects on neuronal ubiquitin hydrolases UCH-L1 and UCH-L3 as well as on proteasome activity. Notably, Delta12-PGJ2 inhibited the activities of UCH-L1 (K(i) approximately 3.5 microM) and UCH-L3 (K(i) approximately 8.1 microM) without affecting proteasome activity. Intracellular aggregates containing ubiquitinated proteins were detected in Delta12-PGJ2-treated cells, indicating that these aggregates can form independently of proteasome inhibition. In conclusion, impairment of ubiquitin hydrolase activity, such as triggered by Delta12-PGJ2, may be an important contributor to neurodegeneration associated with accumulation of ubiquitinated proteins and inflammation.

Do ACE inhibitors or angiotensin II antagonists reduce total mortality and arrhythmic mortality? A critical review of controlled clinical trials.

ACE-inhibitors (ACE-I) represent effective drugs more and more widely used in acute myocardial infarction (AMI) patients, in post AMI patients and mainly, today, in CHF patients.A complete review of the scientific literature and of all the randomized controlled clinical trials (RCTs), where ACE-I have been tested directly or in association with other drugs, have been performed. ACE-I effects on total mortality (TM) and arrhythmic mortality (AM) and other composite clinical endpoints have been evaluated. It is well known that frequent ventricular arrhythmias (VA) and a high incidence of sudden death (SD) can be documented in CHF patients; nevertheless a direct relationship between VA, TM, and AM has not been clearly demonstrated; neither beneficial effects, on the same endpoints, of the treatment and suppression of ambient VA in CHF. Conversely, sometimes clear negative effects on both TM and AM have been observed. According to individual studies and two recent complete and large metanalysis, ACE-I were unable to reduce AM, but they reduced TM. Furthermore, they can affect and modify many, if not all, of the triggering factors of VA and SD in this context. Differently from ACE-I, betablockers (BB) have been clearly associated with a reduction in TM and AM, in the same context. Thus, at present time, ACE-I, with or without BB, should be considered the standard therapy in all patients with CHF, if not contraindicated. Angiotensin II antagonists (AII-a) probably represent a comparably effective treatment, in all CHF patients and mainly in those patients, suffering from side effects or showing intolerance to ACE-I, but we are still lacking definitive data from RCTs. In many RCTs, conducted with traditional antiarrhythmic drug therapy (ADT), these drugs have been widely used, contributing probably, in a consistent way, to some of the positive results of these studies. All primary and some secondary implantable defibrillators (ICD) RCTs, in the prevention of SD, have included these drugs as the standard treatment of the underlying cardiac disease, with or without CHF. The same therapeutical strategy is regularly applied in all biventricular pacing (BP) RCTs, with or without the ICD. These trials are supposed to assess the reduction in TM and AM, preventing deterioration or progression of CHF and improving the quality of the patients' s life.Finally, according to these clinical evidences, in the last part of the review, we stress the need for a more widespread implementation of ACE-I and AII-a in treating CHF patients.