Comparative studies of diverged members of the phosphotriesterase family

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaf 23).Some genes direct the synthesis of specific proteins called enzymes that catalyze specific types of chemical reactions. The class of enzyme of interest in this research, the hydrolases, catalyzes the conversion of functional groups to water. The phosphotriesterase (PTE) family is a subgroup of hydrolases that breaks down organophosphate compounds (OPs). Many organophosphate compounds are potent cholinesterase inhibitors, accounting for their widespread use as insecticides and nerve agents. Enzymes have been found in bacteria and higher organisms that specifically breakdown OPs. One of these enzymes, human serum paraoxonase/arylesterase (PON1), is a calcium-dependent, HDL (High Density Lipoprotein) -associated protein that appears to have multiple roles in vivo. In one guise, PON1 hydrolyses organophosphate insecticides and nerve gases and is responsible for determining the selective toxicity of these compounds in mammals. Using the sequence available in NCBI Genebank, primers flanking the coding region of PON1 were designed and used to screen a human liver cDNA library using polymerase chain reaction (PCR). A single band corresponding to the approximate size of PON1, 1kb, was amplified and subsequently cloned. The identity of the cloned region as PON1 was verified by sequencing using PON1 specific primers, and then cloned into a plasmid named pTYB1 from the IMPACT-CN expression system. Expression was obtained using the BL21-star bacterial strain. The enzyme was found within an inclusion body, and solubilized with urea and DTT. Preliminary activity studies were unsuccessful, so further manipulation of the insoluble fraction is necessary to obtain proper folding

Complement Activation in Patients With Probable Systemic Lupus Erythematosus and Ability to Predict Progression to American College of Rheumatology-Classified Systemic Lupus Erythematosus.

ObjectiveTo evaluate the frequency of cell-bound complement activation products (CB-CAPs) as a marker of complement activation in patients with suspected systemic lupus erythematosus (SLE) and the usefulness of this biomarker as a predictor of the evolution of probable SLE into SLE as classified by the American College of Rheumatology (ACR) criteria.MethodsPatients in whom SLE was suspected by lupus experts and who fulfilled 3 ACR classification criteria for SLE (probable SLE) were enrolled, along with patients with established SLE as classified by both the ACR and the Systemic Lupus International Collaborating Clinics (SLICC) criteria, patients with primary Sjögren's syndrome (SS), and patients with other rheumatic diseases. Individual CB-CAPs were measured by flow cytometry, and positivity rates were compared to those of commonly assessed biomarkers, including serum complement proteins (C3 and C4) and autoantibodies. The frequency of a positive multianalyte assay panel (MAP), which includes CB-CAPs, was also evaluated. Probable SLE cases were followed up prospectively.ResultsThe 92 patients with probable SLE were diagnosed more recently than the 53 patients with established SLE, and their use of antirheumatic medications was lower. At the enrollment visit, more patients with probable SLE were positive for CB-CAPs (28%) or MAP (40%) than had low complement levels (9%) (P = 0.0001 for each). In probable SLE, MAP scores of >0.8 at enrollment predicted fulfillment of a fourth ACR criterion within 18 months (hazard ratio 3.11, P < 0.01).ConclusionComplement activation occurs in some patients with probable SLE and can be detected with higher frequency by evaluating CB-CAPs and MAP than by assessing traditional serum complement protein levels. A MAP score above 0.8 predicts transition to classifiable SLE according to ACR criteria

Neutrophils isolated from systemic lupus erythematosus patients exhibit a distinct functional phenotype

Neutrophil dysregulation, particularly of a low-density subset, is associated with systemic lupus erythematosus (SLE); however, the exact role of normal-density neutrophils in SLE remains unknown. This study compares activation and functional phenotypes of neutrophils from SLE patients and healthy controls to determine potential contributions to SLE pathogenesis. Surface activation markers and release of neutrophil extracellular traps (NETs), granule proteins, and cytokines/chemokines were measured in resting and stimulated neutrophils from SLE patients (n=19) and healthy controls (n=10). Select miRNA and mRNA involved in neutrophil development and function were also measured. Resting SLE neutrophils exhibited fewer activation markers compared to control neutrophils, and activation markers were associated with different plasma cytokines/chemokines in SLE patients compared to healthy controls. However, activation markers increased similarly in SLE and control neutrophils following stimulation with a TLR7/8 agonist, neutrophil growth factors, and bacterial mimic. At the resting state, SLE neutrophils produced significantly more CXCL10 (IP-10), with trends toward other increased cytokines/chemokines. Following stimulation, SLE neutrophils produced fewer NETs and proinflammatory cytokines compared to control neutrophils but more MMP-8. In addition, SLE neutrophils expressed less miR130a, miR132, miR27a, and miR223. In conclusion, SLE neutrophils exhibit distinct functional responses compared to control neutrophils. These functional differences may result from differential gene expression via miRNAs. Furthermore, the differences in functional phenotype of SLE neutrophils suggest that they may contribute to SLE differently dependent on the inflammatory milieu

Protocol for virtual physical examination in an observational, longitudinal study evaluating virtual outcome measures in SLE

Objective There is a lack of data on the use of telemedicine (TM) in SLE. SLE outcome measures remain complex, and clinicians and clinical trialists have raised concerns about the accuracy of virtual disease activity measures. This study evaluates the level of agreement between virtual SLE outcome measures and face-to-face (F2F) encounter. Here, we describe the study design, virtual physical examination protocol and demographics for the first 50 patients evaluated.Methods and analysis This is an observational, longitudinal study of 200 patients with SLE with varying levels of disease activity from 4 academic lupus centres serving diverse populations. Each study participant will be evaluated at a baseline and a follow-up visit. At each visit, participants are evaluated by the same physician first via a videoconference-based TM and then a F2F encounter. For this protocol, virtual physical examination guidelines relying on physician-directed patient self-examination were established. SLE disease activity measures will be completed immediately after the TM encounter and repeated after the F2F encounter for each visit. The degree of agreement between TM and F2F disease activity measures will be analysed using the Bland-Altman method. An interim analysis is planned after the enrolment of the first 50 participants.Ethics and dissemination This study has been reviewed by the Columbia University Medical Center Institutional Review Board (IRB Protocol #: AAAT6574). The full results of this study will be published after the final data analysis of 200 patients. The abrupt shift to TM visits due to the COVID-19 pandemic disrupted clinical practice and clinical trials. Establishing a high level of agreement between SLE disease activity measures obtained with videoconference TM and F2F at the same time point, will allow for improved assessment of disease activity when F2F data cannot be acquired. This information may guide both medical decision-making and provide reliable outcome measures for clinical research