Coarse-Grained Model of SNARE-Mediated Docking

AbstractSynaptic transmission requires that vesicles filled with neurotransmitter molecules be docked to the plasma membrane by the SNARE protein complex. The SNARE complex applies attractive forces to overcome the long-range repulsion between the vesicle and membrane. To understand how the balance between the attractive and repulsive forces defines the equilibrium docked state we have developed a model that combines the mechanics of vesicle/membrane deformation with an apparently new coarse-grained model of the SNARE complex. The coarse-grained model of the SNARE complex is calibrated by comparison with all-atom molecular dynamics simulations as well as by force measurements in laser tweezer experiments. The model for vesicle/membrane interactions includes the forces produced by membrane deformation and hydration or electrostatic repulsion. Combining these two parts, the coarse-grained model of the SNARE complex with membrane mechanics, we study how the equilibrium docked state varies with the number of SNARE complexes. We find that a single SNARE complex is able to bring a typical synaptic vesicle to within a distance of ∼3 nm from the membrane. Further addition of SNARE complexes shortens this distance, but an overdocked state of >4–6 SNAREs actually increases the equilibrium distance

Rumor Surveillance and Avian Influenza H5N1

We describe the enhanced rumor surveillance during the avian influenza H5N1 outbreak in 2004. The World Health Organization’s Western Pacific Regional Office identified 40 rumors; 9 were verified to be true. Rumor surveillance informed immediate public health action and prevented unnecessary and costly responses

Epithelial cell–derived secreted and transmembrane 1a signals to activated neutrophils during pneumococcal pneumonia

Airway epithelial cell responses are critical to the outcome of lung infection. In this study, we aimed to identify unique contributions of epithelial cells during lung infection. To differentiate genes induced selectively in epithelial cells during pneumonia, we compared genome-wide expression profiles from three sorted cell populations: epithelial cells from uninfected mouse lungs, epithelial cells from mouse lungs with pneumococcal pneumonia, and nonepithelial cells from those same infected lungs. Of 1,166 transcripts that were more abundant in epithelial cells from infected lungs compared with nonepithelial cells from the same lungs or from epithelial cells of uninfected lungs, 32 genes were identified as highly expressed secreted products. Especially strong signals included two related secreted and transmembrane (Sectm) 1 genes, Sectm1a and Sectm1b. Refinement of sorting strategies suggested that both Sectm1 products were induced predominantly in conducting airway epithelial cells. Sectm1 was induced during the early stages of pneumococcal pneumonia, and mutation of NF-kB RelA in epithelial cells did not diminish its expression. Instead, type I IFN signaling was necessary and sufficient for Sectm1 induction in lung epithelial cells, mediated by signal transducer and activator of transcription 1. For target cells, Sectm1a bound to myeloid cells preferentially, in particular Ly6GbrightCD11bbright neutrophils in the infected lung. In contrast, Sectm1a did not bind to neutrophils from uninfected lungs. Sectm1a increased expression of the neutrophil-attracting chemokine CXCL2 by neutrophils from the infected lung. We propose that Sectm1a is an epithelial product that sustains a positive feedback loop amplifying neutrophilic inflammation during pneumococcal pneumonia

Randomised phase 2 study (JADE) of the HBV capsid assembly modulator JNJ-56136379 with or without a nucleos(t)ide analogue in patients with chronic hepatitis B infection

Chronic hepatitis; Hepatitis BHepatitis crònica; Hepatitis BHepatitis crónica; Hepatitis BObjective We present the final analysis results of the phase 2 JADE study (ClinicalTrials.gov Identifier: NCT03361956). Design 232 patients with chronic hepatitis B (CHB) not currently treated at study start (NCT) at study start or virologically suppressed were randomised to receive 75 mg (part 1) or 250 mg (part 2) JNJ-56136379, a hepatitis B virus (HBV)–capsid assembly modulator, one time per day or placebo with nucleos(t)ide analogue (NA) (tenofovir disoproxil fumarate/entecavir) or JNJ-56136379 alone (NCT-only) for ≥24 and ≤48 weeks. Results In patients who are NCT hepatitis B e-antigen (HBeAg) positive, JNJ-56136379 75 mg+NA and 250 mg+NA showed limited mean (SE) hepatitis B surface antigen (HBsAg) declines (0.14 (0.10) and 0.41 (0.15), respectively) from baseline at Week 24 (primary endpoint; placebo+NA: 0.25 (0.11) log10 international unit (IU)/mL). In patients who are NCT HBeAg positive, mean (SE) HBV DNA declines at Week 24 were 5.53 (0.23) and 5.88 (0.34) for JNJ-56136379 75 mg+NA and 250 mg+NA, respectively, versus 5.21 (0.42) log10 IU/mL for placebo+NA. In NCT patients, mean (SE) HBV RNA declines were 2.96 (0.23) and 3.15 (0.33) versus 1.33 (0.32) log10 copies/mL, respectively. Patients with HBsAg declines had HBeAg and hepatitis B core-related antigen (HBcrAg) declines and some early on-treatment isolated alanine aminotransferase flares. Viral breakthrough occurred with JNJ-56136379 monotherapy with the emerging resistant-variant T33N, but not with JNJ-56136379+NA. JNJ-56136379 treatment beyond Week 24 had a generally small additional effect on viral markers. No study treatment-related serious adverse events or clinically significant changes in laboratory parameters occurred. Conclusions In patients with non-cirrhotic CHB, JNJ-56136379+NA showed pronounced reductions in HBV DNA and HBV RNA, limited HBsAg or HBeAg declines in patients who are NCT HBeAg positive, and was well tolerated, but no clear benefit with regards to efficacy of JNJ-56136379 over NA was observed.This study was sponsored by Janssen (award/grant number: not applicable)

hepatitis b virus infection and the kidney renal abnormalities in hbv patients antiviral drugs handling and specific follow up

Chronic hepatitis B virus (CHB) infection is one of the most common causes of chronic liver disease, cirrhosis, and hepatocellular carcinoma (HCC) worldwide. Many patients with CHB have variable degrees of functional renal impairment, and approximately 2 to 15% of patients on hemodialysis have CHB. Several therapeutic regimens have been developed in the past years, among which oral nucleoside and nucleotide analogues have been demonstrated to be efficient and well tolerated. However, they all are excreted in the urine and may thus require dosage adjustment in patients with decreased renal function. Furthermore, a number of them may in addition be toxic to the kidneys, especially in those patients presenting with renal insufficiency

Tenofovir alafenamide and tenofovir disoproxil fumarate reduce incidence of hepatocellular carcinoma in patients with chronic hepatitis B

Antiviral therapy; IncidenceTerapia antiviral; IncidenciaTeràpia antiviral; IncidènciaBackground & Aims Antiviral therapy may attenuate the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). We aimed to explore how tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) affect HCC risk in patients with CHB. Methods The REACH-B, aMAP, and mPAGE-B models were utilized to assess HCC risk in patients with CHB from two global randomized-controlled trials evaluating the impact of TAF vs. TDF treatment. Standard incidence ratios (SIRs) were calculated using data from the REACH-B model as a ratio of observed HCC cases in the TAF- or TDF-treated patients vs. predicted HCC cases for untreated historical controls. Proportions of treated patients shifting aMAP and mPAGE-B risk categories between baseline and Week 240 were calculated. Results Of the 1,632 patients (TAF, n = 1,093; TDF, n = 539) followed for up to 300 weeks, 22 HCC cases developed. Those receiving TAF had an SIR that was lower compared to the SIR of individuals receiving TDF: 0.32 (p <0.001) vs. 0.56 (p = 0.06). In the general study population, individuals without cirrhosis at baseline had an SIR that was lower compared to the SIR of individuals with cirrhosis at baseline: 0.37 (p <0.001) vs. 0.58 (p = 0.15). Of the patients at low risk of HCC at baseline, the majority (97%) remained low risk by mPAGE-B and aMAP scoring at Week 240. Among those at medium or high risk at baseline, substantial portions shifted to a lower risk category by Week 240 (mPAGE-B: 22% and 42%; aMAP: 39% and 63%, respectively). Conclusions This evaluation provides evidence that treatment with TAF or TDF can reduce HCC risk in patients with CHB, particularly in patients without cirrhosis. Impact and implications Despite the substantial impact of HCC on long-term outcomes of patients with CHB, the differential risk of HCC development among those receiving treatment with TAF vs. TDF has not been well elucidated. Using three validated risk prediction models, we found that TAF is at least as effective as TDF in reducing HCC risk in patients with CHB. While TDF is well-studied in the context of HCC risk reduction, our novel findings underscore the effectiveness of TAF as a treatment option for patients with CHB. Clinical trial numbers NCT01940341; NCT02836249; NCT01940471; NCT02836236.This study was sponsored by Gilead Sciences. This article was based on the original studies GS-US-320-0108 and GS-US-320-0110 sponsored by Gilead Sciences. Support for third-party writing assistance for this article, provided by Julianna Catania, MPH, and Isabel Haber, BS, Costello Medical, US, was funded by Gilead in accordance with Good Publication Practice (GPP3) guidelines (http://www.ismpp.org/gpp3)

Fusion-dependent formation of lipid nanoparticles containing macromolecular payloads

The success of Onpattro™ (patisiran) clearly demonstrates the utility of lipid nanoparticle (LNP) systems for enabling gene therapies. These systems are composed of ionizable cationic lipids, phospholipid, cholesterol, and polyethylene glycol (PEG)-lipids, and are produced through rapid-mixing of an ethanolic-lipid solution with an acidic aqueous solution followed by dialysis into neutralizing buffer. A detailed understanding of the mechanism of LNP formation is crucial to improving LNP design. Here we use cryogenic transmission electron microscopy and fluorescence techniques to further demonstrate that LNP are formed through the fusion of precursor, pH-sensitive liposomes into large electron-dense core structures as the pH is neutralized. Next, we show that the fusion process is limited by the accumulation of PEG-lipid on the emerging particle. Finally, we show that the fusion-dependent mechanism of formation also applies to LNP containing macromolecular payloads including mRNA, DNA vectors, and gold nanoparticles