Spatiotemporal regulation of a Legionella pneumophila T4SS substrate by the metaeffector SidJ

Modulation of host cell function is vital for intracellular pathogens to survive and replicate within host cells. Most commonly, these pathogens utilize specialized secretion systems to inject substrates (also called effector proteins) that function as toxins within host cells. Since it would be detrimental for an intracellular pathogen to immediately kill its host cell, it is essential that secreted toxins be inactivated or degraded after they have served their purpose. The pathogen Legionella pneumophila represents an ideal system to study interactions between toxins as it survives within host cells for approximately a day and its Dot/Icm type IVB secretion system (T4SS) injects a vast number of toxins. Previously we reported that the Dot/Icm substrates SidE, SdeA, SdeB, and SdeC (known as the SidE family of effectors) are secreted into host cells, where they localize to the cytoplasmic face of the Legionella containing vacuole (LCV) in the early stages of infection. SidJ, another effector that is unrelated to the SidE family, is also encoded in the sdeC-sdeA locus. Interestingly, while over-expression of SidE family proteins in a wild type Legionella strain has no effect, we found that their over-expression in a ∆sidJ mutant completely inhibits intracellular growth of the strain. In addition, we found expression of SidE proteins is toxic in both yeast and mammalian HEK293 cells, but this toxicity can be suppressed by co-expression of SidJ, suggesting that SidJ may modulate the function of SidE family proteins. Finally, we were able to demonstrate both in vivo and in vitro that SidJ acts on SidE proteins to mediate their disappearance from the LCV, thereby preventing lethal intoxication of host cells. Based on these findings, we propose that SidJ acts as a metaeffector to control the activity of other Legionella effectors

Quaternary faulting in the New Madrid seismic zone in southernmost Illinois

U.S. Geological Survey, Department of the Interior, under USGS award number 1434-95-G-2525Ope

The Prodomain of the Bordetella Two-Partner Secretion Pathway Protein FhaB Remains Intracellular yet Affects the Conformation of the Mature C-terminal Domain

Two-Partner Secretion (TPS) systems use β-barrel proteins of the Omp85-TpsB superfamily to transport large exoproteins across the outer membranes of Gram-negative bacteria. The Bordetella FHA/FhaC proteins are prototypical of TPS systems in which the exoprotein contains a large C-terminal prodomain that is removed during translocation. Although it is known that the FhaB prodomain is required for FHA function in vivo, its role in FHA maturation has remained mysterious. We show here that the FhaB prodomain is required for the extracellularly-located mature C-terminal domain (MCD) of FHA to achieve its proper conformation. We show that the C-terminus of the prodomain is retained intracellularly and that sequences within the N-terminus of the prodomain are required for this intracellular localization. We also identify sequences at the C-terminus of the MCD that are required for release of mature FHA from the cell surface. Our data support a model in which the intracellularly-located prodomain affects the final conformation of the extracellularly-located MCD, which, we hypothesize, triggers cleavage and degradation of the prodomain

All-cause and cause-specific mortality in rheumatoid arthritis, psoriatic arthritis and axial spondyloarthritis : a nationwide registry study

Objectives To explore mortality and causes of death among Norwegian patients with RA, PsA and axial spondyloarthritis (axSpA) compared with the general population by conducting a nationwide registry-based cohort study. Methods Patients with RA, PsA and axSpA were identified from the Norwegian Patient Registry based on ICD-10 codes between 2008 and 2017. Using age as the time variable, all-cause and cause-specific mortality were estimated between 2010 and 2017 with the Kaplan-Meier estimator and the cumulative incidence competing risk method, respectively. Sex-, education level-, health region- and age group-adjusted hazard ratios (HRs) for mortality were estimated using Cox regression models. Results We identified 36 095 RA, 18 700 PsA and 16 524 axSpA patients (70%, 53% and 45% women, respectively). RA and axSpA were associated with increased all-cause mortality (HR 1.45 [95% CI: 1.41, 1.48] and HR 1.38 [95% CI: 1.28, 1.38], respectively). Women but not men with PsA had a slightly increased mortality rate (HR 1.10 [95% CI: 1.00, 1.21] among women and 1.02 [95% CI: 0.93, 1.11] among men). For all patient groups as well as for the general population, the three leading causes of death were cardiovascular diseases, neoplasms and respiratory diseases. RA patients had increased mortality from all of these causes, while axSpA patients had increased mortality from cardiovascular and respiratory diseases. Conclusion Even in the era of modern treatments for IJDs, patients with RA and axSpA still have shortened life expectancy. Our findings warrant further attention to the prevention and management of comorbidities.Peer reviewe

Chemoradiotherapy in octogenarians as primary treatment for muscle-invasive bladder cancer

Introduction: While radical cystectomy is the gold standard for muscle-invasive bladder cancer (MIBC), in octogenarians cystectomy results in a higher perioperative mortality rate (6.8‒11.1%) than in younger patients (2.2%). Trimodality therapy is a bladder-sparing regimen composed of transurethral resection of bladder tumour (TURBT) and chemoradiotherapy, with intent for salvage cystectomy, and has a 62.5‒90% initial complete response rate. In this study, we evaluate TURBT and chemoradiotherapy without salvage cystectomy in medically inoperable octogenarian patients. Methods: We identified a retrospective cohort of patients aged 80‒89 years with invasive urothelial carcinoma who received combination chemoradiotherapy between 2008 and June 2014. Outcomes were evaluated by Kaplan-Meier (KM) and Cox regression. Results: In 40 patients, the mean age was 84.5 years (interquartile range [IQR] 83‒86). Seventeen patients received hypofractionated, low-dose radiotherapy (LD) (37.5‒40 Gy), while 23 received conventionally fractionated radiotherapy (high-dose [HD]) (50‒65 Gy). Mean overall survival (OS) was 20.7 months (IQR 12.75‒23.25), while mean recurrence-free survival (RFS) was 13.75 months (IQR 3.75‒16.5). Patients receiving HD radiotherapy showed improved OS and local RFS (LRFS) without significant differences in Grade 3‒4 toxicities. Univariate Cox regression identified hydronephrosis as a predictor of worse OS and local recurrence and HD radiotherapy as a predictor of improved OS and local recurrence rates. Multivariate Cox regression identified hydronephrosis to be a significant predictor of LRFS. Conclusions: Primary chemoradiotherapy for inoperable patients with MIBC resulted in a three-year OS of 54.9% (comparable to cystectomy) and three-year RFS of 42.3%. Superior outcomes were associated with more aggressive chemoradiotherapy treatment. The results of the local control subanalyses in this study are hypothesis-generating due to the limited patient numbers in the cohort

Incidence, sociodemographic factors and treatment penetration of rheumatoid arthritis and psoriatic arthritis in Norway

ABSTR A C T Objectives: To evaluate nationwide incidence, sociodemographic associations and treatment penetration of rheumatoid arthritis (RA) and psoriatic arthritis (PsA) in Norway. Methods: The study combined data from nationwide registries on the total Norwegian adult population (age > 18). From the Norwegian Patient Registry, incident RA and PsA cases during 2011-2015 were identified with records of first and second healthcare episodes listing RA/PsA diagnostic codes, and > 1 episode in an internal medicine or rheumatology unit with RA/PsA code during the two-year period after the first episode. Dispensed DMARD prescriptions were obtained from the Norwegian Prescription Database. Persons with dis-pensed DMARD prescriptions or biologic DMARDs given in hospitals > 12 months before the index date were excluded. Results: Incidence of RA/PsA in Norway was 42/26 per 100,000 person-years (55/28 among women and 28/23 among men). RA peak incidence was observed at ages 70-79 in both sexes, whereas the peak incidence of PsA occurred at ages 50-59. Age-and sex-standardized incidences of RA and PsA were lower among persons with higher education levels. Within a year from the index date, 82.4/57.4% of RA/PsA patients used synthetic DMARDs while 9.4/9.5% used biologic DMARDs. Conclusions: Register-based incidence estimates for RA and PsA in Norway are similar to other Nordic countries, but slightly higher than in previous Norwegian studies. Furthermore, we found that higher socioeconomic status was associated with lower incidence of both RA and PsA. Although conventional synthetic DMARDs were less often used in early PsA than RA, frequency of biologic DMARD prescriptions was comparable. (c) 2021 Elsevier Inc. All rights reserved.Peer reviewe

Wholly Rickettsia! Reconstructed Metabolic Profile of the Quintessential Bacterial Parasite of Eukaryotic Cells

Reductive genome evolution has purged many metabolic pathways from obligate intracellular Rickettsia (Alphaproteobacteria; Rickettsiaceae). While some aspects of host-dependent rickettsial metabolism have been characterized, the array of host-acquired metabolites and their cognate transporters remains unknown. This dearth of information has thwarted efforts to obtain an axenic Rickettsia culture, a major impediment to conventional genetic approaches. Using phylogenomics and computational pathway analysis, we reconstructed the Rickettsia metabolic and transport network, identifying 51 host-acquired metabolites (only 21 previously characterized) needed to compensate for degraded biosynthesis pathways. In the absence of glycolysis and the pentose phosphate pathway, cell envelope glycocon- jugates are synthesized from three imported host sugars, with a range of additional host-acquired metabolites fueling the tricarboxylic acid cycle. Fatty acid and glycero- phospholipid pathways also initiate from host precursors, and import of both iso- prenes and terpenoids is required for the synthesis of ubiquinone and the lipid car- rier of lipid I and O-antigen. Unlike metabolite-provisioning bacterial symbionts of arthropods, rickettsiae cannot synthesize B vitamins or most other cofactors, accen- tuating their parasitic nature. Six biosynthesis pathways contain holes (missing en- zymes); similar patterns in taxonomically diverse bacteria suggest alternative en- zymes that await discovery. A paucity of characterized and predicted transporters emphasizes the knowledge gap concerning how rickettsiae import host metabolites, some of which are large and not known to be transported by bacteria. Collectively, our reconstructed metabolic network offers clues to how rickettsiae hijack host met- abolic pathways. This blueprint for growth determinants is an important step toward the design of axenic media to rescue rickettsiae from the eukaryotic cell

Cola rostrata K. Schum. constituents induce cytotoxicity through reactive oxygen species generation and mitochondrial membrane depolarisation

Aim: While the traditional use of Cola rostrata in treating illnesses and diseases has not been reported, the presence of cytotoxic principles has been reported in phylogenetically and biogeographically related species within the Cola genus. This study, therefore, evaluated the cytotoxic potential of extracts of the plant, and the associated cellular and molecular mechanisms. Methods: Activity-based fractionation of the extracts was carried out and cytotoxicity was assessed in the human cervical cancer cell line, HeLa, and the transformed human lung cell line, MRC5-SV2, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay complemented with brightfield imaging. The 2ʼ,7ʼ-dichlorofluorescein diacetate (DCFDA) assay was used to assess induction of cellular reactive oxygen species (ROS), while flow cytometry of 5,5ʼ,6,6ʼ-tetrachloro-1,1ʼ,3,3ʼ-tetraethyl-imidacarbocyanine iodide (JC-1)-stained cells assessed the loss of mitochondrial membrane potential (∆ΨM). Gas chromatography-mass spectrometry (GC-MS) analysis was carried out on an active fraction. Results: Extracts of the fruit epicarp and leaf were cytotoxic against the cell lines. Half-maximal inhibitory concentration (IC50) values for the 48 h cytotoxicity of the ethanol extract of the epicarp against HeLa and MRC5-SV2 cells were 48.0 μg/mL ± 12.1 μg/mL and 40.4 μg/mL ± 7.2 μg/mL, respectively, while fractions from second-level partitioning of the hexane fraction of the leaf extract elicited cytotoxicity with IC50 values ranging from 12.8 μg/mL ± 1.0 μg/mL to 39.6 μg/mL ± 7.2 μg/mL in both cell lines, following 48 h treatment. GC-MS revealed the presence of seventeen compounds in a hexane fraction of the leaf extract, including even- and odd-chain fatty acids, the most abundant of which were n-hexadecanoic acid, decanoic acid 10-(2-hexylcyclopropyl); and octadecanoic acid. The mechanisms of cytotoxicity of most active fractions involved generation of ROS and mitochondrial membrane depolarisation. Conclusions: The findings show that C. rostrata is rich in cytotoxic phytochemicals which could be isolated for developing new anti-cancer agents