Characterization of Major Surface Protease Homologues of Trypanosoma congolense

Trypanosomes encode a family of proteins known as Major Surface Metalloproteases (MSPs). We have identified six putative MSPs encoded within the partially sequenced T. congolense genome. Phylogenic analysis indicates that T. congolense MSPs belong to five subfamilies that are conserved among African trypanosome species. Molecular modeling, based on the known structure of Leishmania Major GP63, reveals subfamily-specific structural variations around the putative active site despite conservation of overall structure, suggesting that each MSP subfamily has evolved to recognize distinct substrates. We have cloned and purified a protein encoding the amino-terminal domain of the T. congolense homologue TcoMSP-D (most closely related to Leishmania GP63). We detect TcoMSP-D in the serum of T. congolense-infected mice. Mice immunized with the amino-terminal domain of TcoMSP-D generate a persisting IgG1 antibody response. Surprisingly, a low-dose challenge of immunized mice with T. congolense significantly increases susceptibility to infection, indicating that immunity to TcoMSP-D is a factor affecting virulence

Prevalence and characteristics of progressive fibrosing interstitial lung disease in a prospective registry

Rationale Progressive fibrosing interstitial lung disease (PF-ILD) is characterized by progressive physiologic, symptomatic, and/or radiographic worsening. The real-world prevalence and characteristics of PF-ILD remain uncertain. Methods Patients were enrolled from the Canadian Registry for Pulmonary Fibrosis between 2015-2020. PF-ILD was defined as a relative forced vital capacity (FVC) decline ≥10%, death, lung transplantation, or any 2 of: relative FVC decline ≥5 and <10%, worsening respiratory symptoms, or worsening fibrosis on computed tomography of the chest, all within 24 months of diagnosis. Time-to-event analysis compared progression between key diagnostic subgroups. Characteristics associated with progression were determined by multivariable regression. Results Of 2,746 patients with fibrotic ILD (mean age 65±12 years, 51% female), 1,376 (50%) met PFILD criteria in the first 24 months of follow-up. PF-ILD occurred in 427 (59%) patients with idiopathic pulmonary fibrosis (IPF), 125 (58%) with fibrotic hypersensitivity pneumonitis (HP), 281 (51%) with unclassifiable ILD (U-ILD), and 402 (45%) with connective tissue diseaseassociated ILD (CTD-ILD). Compared to IPF, time to progression was similar in patients with HP (hazard ratio [HR] 0.96, 95% confidence interval, CI 0.79-1.17), but was delayed in patients with U-ILD (HR 0.82, 95% CI 0.71-0.96) and CTD-ILD (HR 0.65, 95% CI 0.56-0.74). Background treatment varied across diagnostic subtypes with 66% of IPF patients receiving antifibrotic therapy, while immunomodulatory therapy was utilized in 49%, 61%, and 37% of patients with CHP, CTD-ILD, and U-ILD respectively. Increasing age, male sex, gastroesophageal reflux disease, and lower baseline pulmonary function were independently associated with progression. Interpretation Progression is common in patients with fibrotic ILD, and is similarly prevalent in HP and IPF. Routinely collected variables help identify patients at risk for progression and may guide therapeutic strategie

The clinical frailty scale for risk stratification in patients with fibrotic interstitial lung disease.

BACKGROUND Previous studies have shown the importance of frailty in patients with fibrotic interstitial lung disease (ILD). RESEARCH QUESTION Is the Clinical Frailty Scale (CFS) a valid tool to improve risk stratification in patients with fibrotic ILD? STUDY DESIGN AND METHODS Patients with fibrotic ILD were included from the prospective multicenter Canadian Registry for Pulmonary Fibrosis. The CFS was assessed using available information from initial ILD clinic visits. Patients were stratified into fit (CFS 1-3), vulnerable (CFS 4), and frail (CFS 5-9) subgroups. Cox proportional hazards and logistic regression models with mixed effects were used to estimate time to death or lung transplantation. A derivation and validation cohort were used to establish prognostic performance. Trajectories of functional tests were compared using joint models. RESULTS Of the 1587 patients with fibrotic ILD, 858 (54%) were fit, 400 (25%) vulnerable and 329 (21%) frail. Frailty was a risk factor for early mortality (HR 5.58, 95%CI 3.64-5.76, p<0.001) in the entire cohort, in individual ILD diagnoses, and after adjustment for potential confounders. Adding frailty to established risk prediction parameters improved the prognostic performance in derivation and validation cohorts. Frail patients had larger annual declines in forced vital capacity (FVC) %-predicted compared to fit patients (-2.32 (95%CI -3.39 to -1.17) vs. -1.55 (95%CI -2.04 to -1.15); p=0.02, respectively). INTERPRETATION The simple and practical CFS is associated with pulmonary and physical function decline in patients with fibrotic ILD and provides additional prognostic accuracy in clinical practice

Substrate-bound and substrate-free outward-facing structures of a multidrug ABC exporter

International audienceMultidrug ABC transporters translocate drugs across membranes by a mechanism for which the molecular features of drug release are so far unknown. Here, we resolved three ATP-Mg$^{2+}$–bound outward-facing conformations of the $Bacillus\ subtilis$ (homodimeric) BmrA by x-ray crystallography and single-particle cryo–electron microscopy (EM) in detergent solution, one of them with rhodamine 6G (R6G), a substrate exported by BmrA when overexpressed in $B.\ subtilis$ . Two R6G molecules bind to the drug-binding cavity at the level of the outer leaflet, between transmembrane (TM) helices 1–2 of one monomer and TM5′–6′ of the other. They induce a rearrangement of TM1–2, highlighting a local flexibility that we confirmed by hydrogen/deuterium exchange and molecular dynamics simulations. In the absence of R6G, simulations show a fast postrelease occlusion of the cavity driven by hydrophobicity, while when present, R6G can move within the cavity, maintaining it open

Neighbourhood disadvantage impacts on pulmonary function in patients with sarcoidosis

Background This multicentre, international, prospective cohort study evaluated whether patients with pulmonary sarcoidosis living in neighbourhoods with greater material and social disadvantage experience worse clinical outcomes. Methods The area deprivation index and the Canadian Index of Multiple Deprivation evaluate neighbourhood-level disadvantage in the US and Canada, with higher scores reflecting greater disadvantage. Multivariable linear regression evaluated associations of disadvantage with baseline forced vital capacity (FVC) or diffusing capacity of the lung for carbon monoxide (DLCO) and linear mixed effects models for associations with rate of FVC or DLCO decline, and competing hazards models were used for survival analyses in the US cohort, evaluating competing outcomes of death or lung transplantation. Adjustments were made for age at diagnosis, sex, race and smoking history. Results We included 477 US and 122 Canadian patients with sarcoidosis. Higher disadvantage was not associated with survival or baseline FVC. The highest disadvantage quartile was associated with lower baseline DLCO in the US cohort (β = −6.80, 95% CI −13.16 to −0.44, p=0.04), with similar findings in the Canadian cohort (β = −7.47, 95% CI −20.28 to 5.33, p=0.25); with more rapid decline in FVC and DLCO in the US cohort (FVC β = −0.40, 95% CI −0.70 to −0.11, p=0.007; DLCO β = −0.59, 95% CI −0.95 to −0.23, p=0.001); and with more rapid FVC decline in the Canadian cohort (FVC β = −0.80, 95% CI −1.37 to −0.24, p=0.003). Conclusion Patients with sarcoidosis living in high disadvantage neighbourhoods experience worse baseline lung function and more rapid lung function decline, highlighting the need for better understanding of how neighbourhood-level factors impact individual patient outcomes

Substrate-bound and substrate-free outward-facing structures of a multidrug ABC exporter

International audienceMultidrug ABC transporters translocate drugs across membranes by a mechanism for which the molecular features of drug release are so far unknown. Here, we resolved three ATP-Mg$^{2+}$–bound outward-facing conformations of the $Bacillus\ subtilis$ (homodimeric) BmrA by x-ray crystallography and single-particle cryo–electron microscopy (EM) in detergent solution, one of them with rhodamine 6G (R6G), a substrate exported by BmrA when overexpressed in $B.\ subtilis$ . Two R6G molecules bind to the drug-binding cavity at the level of the outer leaflet, between transmembrane (TM) helices 1–2 of one monomer and TM5′–6′ of the other. They induce a rearrangement of TM1–2, highlighting a local flexibility that we confirmed by hydrogen/deuterium exchange and molecular dynamics simulations. In the absence of R6G, simulations show a fast postrelease occlusion of the cavity driven by hydrophobicity, while when present, R6G can move within the cavity, maintaining it open

A cluster-based analysis evaluating the impact of comorbidities in fibrotic interstitial lung disease

Background Comorbidities are frequent and have been associated with poor quality of life, increased hospitalizations, and mortality in patients with interstitial lung disease (ILD). However, it is unclear how comorbidities lead to these negative outcomes and whether they could influence ILD disease progression. The goal of this study was to identify clusters of patients based on similar comorbidity profiles and to determine whether these clusters were associated with rate of lung function decline and/or mortality. Methods Patients with a major fibrotic ILD (idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis, connective tissue disease-associated ILD, and unclassifiable ILD) from the CAnadian REgistry for Pulmonary Fibrosis (CARE-PF) were included. Hierarchical agglomerative clustering of comorbidities, age, sex, and smoking pack-years was conducted for each ILD subtype to identify combinations of these features that frequently occurred together in patients. The association between clusters and change in lung function over time was determined using linear mixed effects modeling, with adjustment for age, sex, and smoking pack-years. Kaplan Meier curves were used to assess differences in survival between the clusters. Results Discrete clusters were identified within each fibrotic ILD. In IPF, males with obstructive sleep apnea (OSA) had more rapid decline in FVC %-predicted (− 11.9% per year [95% CI − 15.3, − 8.5]) compared to females without any comorbidities (− 8.1% per year [95% CI − 13.6, − 2.7]; p = 0.03). Females without comorbidities also had significantly longer survival compared to all other IPF clusters. There were no significant differences in rate of lung function decline or survival between clusters in the other fibrotic ILD subtypes. Conclusions The combination of male sex and OSA may portend worse outcomes in IPF. Further research is required to elucidate the interplay between sex and comorbidities in ILD, as well as the role of OSA in ILD disease progression.Medicine, Faculty ofPharmaceutical Sciences, Faculty ofNon UBCMedicine, Department ofReviewedFacult

Mapping EQ5D utilities from forced vital capacity and diffusing capacity in fibrotic interstitial lung disease.

ObjectivesFibrotic interstitial lung disease (ILD) includes a large group of conditions that lead to scarring of the lungs. The lack of available 5-level EuroQol 5D (EQ5D) data has limited the ability to conduct economic evaluations in ILD. The purpose of this study was to develop and validate a mapping algorithm that predicts EQ5D utilities from commonly collected pulmonary function measurements (forced vital capacity [FVC] and diffusing capacity of the lung for carbon monoxide [DLCO]) in fibrotic ILDs.MethodsEQ5D utility and pulmonary function measurements from the Canadian Registry for Pulmonary Fibrosis were included. Ordinary least squares (OLS), beta regression, two-part, and tobit models were used to map EQ5D utilities from FVC or DLCO. Model performance was assessed by comparing the predicted and observed utilities. Subgroup analyses were also conducted to test how well models performed across different patient characteristics. The models were then externally validated in the Australian Idiopathic Pulmonary Fibrosis Registry.ResultsThe OLS model performed as well as other more complex models (root mean squared error: 0.17 for FVC and 0.16 for DLCO). As with the other models, the OLS algorithm performed well across the different subgroups (except for EQ5D utilities ConclusionWe developed a mapping algorithm that predicts EQ5D utilities from FVC and DLCO, with the intent that this algorithm can be applied to clinical trial populations and real-world cohorts that have not prioritized collection of health-related utilities. The mapping algorithm can be used in future economic evaluations of potential ILD therapies

Prescribing Patterns and Tolerability of Mycophenolate and Azathioprine in Patients with Nonidiopathic Pulmonary Fibrosis Fibrotic Interstitial Lung Disease

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