Abstract Objective The assessment of health-related quality-of-life (HRQoL) in rheumatoid arthritis (RA) is becoming increasingly common in both research and clinical practice. One of the most widely ...used tools for measuring HRQoL is the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36). We conducted a systematic review examining the impact of RA on HRQoL, measured through the SF-36. Methods MEDLINE and Embase were searched for observational studies reporting mean and standard deviation scores for each domain of the SF-36 in adult RA patients. Studies were reviewed in accordance with PRISMA guidelines, and a random-effects meta-analysis was performed. Results In total, 31 studies were eligible for inclusion in the meta-analysis, including 22,335 patients. Meta-analyses found that pooled mean HRQoL score for the SF-36 physical component summary was 34.1 (95% CI: 22.0–46.1) and mental component summary was 45.6 (95% CI: 30.3–60.8). Increased age was associated with reduced physical function and physical component summary (PCS) scores but improved mental health and mental component summary (MCS) scores. Female gender was associated with improved scores on role physical, bodily pain and PCS but reduced mental health and MCS scores. Longer disease duration was associated with improved MCS. Patients with RA have a substantially reduced HRQoL in comparison to both other physical illnesses and in comparison to normative datasets from UK and USA populations. Conclusions RA has a substantial impact on HRQoL. This supports recent NICE guidelines stipulating that RA patients should be regularly assessed for the impact their disease has on HRQoL and appropriate management provided.
Gram-negative pathogens ubiquitously shed outer membrane vesicles (OMVs) that play a central role in initiating and regulating pathogenesis in the host. Due to their highly inflammatory nature, OMVs ...are extensively being examined for their role in mediating disease in addition to their applications in innovative vaccines. A key mechanism whereby OMVs mediate inflammation and disease progression is dependent on their ability to enter host cells. Currently, the role of OMV size on determining their mechanism of cellular entry and their protein composition remains unknown. In this study, we examined the mechanisms whereby OMV size regulates their mode of entry into epithelial cells, in addition to their protein cargo and composition. We identified that a heterogeneous sized population of
OMVs entered epithelial cells
macropinocytosis, clathrin, and caveolin-dependent endocytosis. However, smaller OMVs ranging from 20 to 100 nm in size preferentially entered host cells
caveolin-mediated endocytosis. Whereas larger OMVs ranging between 90 and 450 nm in size entered host epithelial cells
macropinocytosis and endocytosis. Most importantly, we identified the previously unknown contribution that OMV size has on determining their protein content, as fewer and less diverse bacterial proteins were contained within small OMVs compared to larger OMVs. Collectively, these findings identify the importance of OMV size in determining the mechanisms of OMV entry into host cells, in addition to regulating their protein cargo, composition, and subsequent immunogenicity. These findings have significant implications in broadening our understanding of the bacterial regulation of virulence determinants and immunogenic proteins associated with OMVs, their role in mediating pathogenesis and in refining the design and development of OMV-based vaccines.
Plasmodium falciparum exports ~10% of its proteome into its host erythrocyte to modify the host cell's physiology. The Plasmodium export element (PEXEL) motif contained within the N-terminus of most ...exported proteins directs the trafficking of those proteins into the erythrocyte. To reach the host cell, the PEXEL motif of exported proteins is processed by the endoplasmic reticulum (ER) resident aspartyl protease plasmepsin V. Then, following secretion into the parasite-encasing parasitophorous vacuole, the mature exported protein must be unfolded and translocated across the parasitophorous vacuole membrane by the Plasmodium translocon of exported proteins (PTEX). PTEX is a protein-conducting channel consisting of the pore-forming protein EXP2, the protein unfoldase HSP101, and structural component PTEX150. The mechanism of how exported proteins are specifically trafficked from the parasite's ER following PEXEL cleavage to PTEX complexes on the parasitophorous vacuole membrane is currently not understood. Here, we present evidence that EXP2 and PTEX150 form a stable subcomplex that facilitates HSP101 docking. We also demonstrate that HSP101 localises both within the parasitophorous vacuole and within the parasite's ER throughout the ring and trophozoite stage of the parasite, coinciding with the timeframe of protein export. Interestingly, we found that HSP101 can form specific interactions with model PEXEL proteins in the parasite's ER, irrespective of their PEXEL processing status. Collectively, our data suggest that HSP101 recognises and chaperones PEXEL proteins from the ER to the parasitophorous vacuole and given HSP101's specificity for the EXP2-PTEX150 subcomplex, this provides a mechanism for how exported proteins are specifically targeted to PTEX for translocation into the erythrocyte.
The aim of this analysis is to examine the longitudinal impact of symptoms of depression/anxiety on treatment response, long-term disease activity and physical disability in RA.
Secondary analysis of ...clinical trial data was performed. Data were collected at baseline and at 6-monthly intervals for 2 years. The EuroQoL (EQ-5D(TM)) indicated depression/anxiety symptom severity. Our primary outcomes of interest were (i) DAS-28 and (ii) physical disability measured via the HAQ. Secondary outcomes were: tender and swollen joint counts, patient global assessment, ESR and odds of reaching clinical remission. Multilevel models were used to assess the impact of baseline and persistent depression/anxiety on outcomes over 2 years.
Data from 379 patients were included. After adjusting for covariates, baseline depression/anxiety symptoms were associated with increased DAS-28 outcomes and increased tender joint counts. Persistent depression/anxiety symptoms were associated with increased DAS-28 scores, HAQ scores, tender joint counts and patient global assessment of disease activity, and reduced odds of reaching clinical remission. Patients with symptoms of depression/anxiety at baseline also showed a 50% reduction in prednisolone treatment effect, in comparison with patients with no symptoms of depression/anxiety at baseline.
Baseline and persistent symptoms of depression/anxiety are associated with poorer health outcomes over time, as well as reduced treatment response. Mental health should be routinely measured both in clinical practice and in research, and managed alongside rheumatological disease to optimize health outcomes. Further research is required to examine whether treatment of mental disorders can improve rheumatological outcomes.
Non-ribosomal peptide synthetases are important enzymes for the assembly of complex peptide natural products. Within these multi-modular assembly lines, condensation domains perform the central ...function of chain assembly, typically by forming a peptide bond between two peptidyl carrier protein (PCP)-bound substrates. In this work, we report structural snapshots of a condensation domain in complex with an aminoacyl-PCP acceptor substrate. These structures allow the identification of a mechanism that controls access of acceptor substrates to the active site in condensation domains. The structures of this complex also allow us to demonstrate that condensation domain active sites do not contain a distinct pocket to select the side chain of the acceptor substrate during peptide assembly but that residues within the active site motif can instead serve to tune the selectivity of these central biosynthetic domains.
Controllable protein attachment onto solid interfaces is essential for the functionality of proteins with broad applications. Silica-binding peptides (SBPs) have emerged as an important tool enabling ...convenient binding of proteins onto a silica surface. Surprisingly, we found that removal of polyhistidines, a common tag for protein purification, dramatically decrease the binding affinity of a SBP-tagged nanobody onto a silica surface. We hypothesized that polyhistidines and SBPs can be combined to enhance affinity. Through a series of purposely designed SBPs, we identified that the relative orientation of amino acids is a key factor affecting the surface binding strength. One re-engineered SBP, SBP4, exhibits a 4000-fold improvement compared to the original sequence. Guided by physical insights, the work provides a simple strategy that can dramatically improve affinity between a SBP and a silica surface, promising a new way for controllable immobilization of proteins, as demonstrated using nanobodies.
An array of oncogenic histone point mutations have been identified across a number of different cancer studies. It has been suggested that some of these mutant histones can exert their effects by ...inhibiting epigenetic writers. Here, we report that the H3.3 G34R (glycine to arginine) substitution mutation, found in paediatric gliomas, causes widespread changes in H3K9me3 and H3K36me3 by interfering with the KDM4 family of K9/K36 demethylases. Expression of a targeted single-copy of H3.3 G34R at endogenous levels induced chromatin alterations that were comparable to a KDM4 A/B/C triple-knockout. We find that H3.3 G34R preferentially binds KDM4 while simultaneously inhibiting its enzymatic activity, demonstrating that histone mutations can act through inhibition of epigenetic erasers. These results suggest that histone point mutations can exert their effects through interactions with a range of epigenetic readers, writers and erasers.
We report our investigation of the utility of peptide crosslinking cytochrome P450 enzymes from biarylitide biosynthesis to generate a range of cyclic tripeptides from simple synthons. The ...crosslinked tripeptides produced by this P450 include both tyrosine‐histidine (A−N−B) and tyrosine‐tryptophan (A−O−B) crosslinked tripeptides, the latter a rare example of a phenolic crosslink to an indole moiety. Tripeptides are easily isolated following proteolytic removal of the leader peptide and can incorporate a wide range of amino acids in the residue inside the crosslinked tripeptide. Given the utility of peptide crosslinks in important natural products and the synthetic challenge that these can represent, P450 enzymes have the potential to play roles as important tools in the generation of high‐value cyclic tripeptides for incorporation in synthesis, which can be yet further diversified using selective chemical techniques through specific handles contained within these tripeptides.
Cytochrome P450Blt generates A−N−B and A−O−B crosslinked tripeptides within MRYxH and MRYxW peptides. Removal of the minimal leader peptide allows isolation of these cyclic tripeptides, with sequences further varied by incorporation of a range of residues at the position within the cyclic tripeptide. Biarylitide P450s therefore show potential as biocatalysts for the generation of a diverse range of cyclic tripeptide building blocks.
Conferring multifunctional properties to proteins via enzymatic approaches has greatly facilitated recent progress in protein nanotechnology. In this regard, sortase (Srt) A transpeptidation has ...facilitated many of these developments due to its exceptional specificity, mild reaction conditions, and complementation with other bioorthogonal techniques, such as click chemistry. In most of these developments, Srt A is used to seamlessly tether oligoglycine-containing molecules to a protein of interest that is equipped with the enzyme’s recognition sequence, LPXTG. However, the dependence on oligoglycine attacking nucleophiles and the associated cost of certain derivatives (e.g., cyclooctyne) limit the utility of this approach to lab-scale applications only. Thus, the quest to identify appropriate alternatives and understand their effectiveness remains an important area of research. This study identifies that steric and nucleophilicity-associated effects influence Srt A transpeptidation when two oligoglycine surrogates were examined. The approach was further used in complementation with click chemistry to synthesize bivalent and bifunctional nanobody conjugates for application in epithelial growth factor receptor targeting. The overall technique and tools developed here may facilitate the advancement of future nanotechnologies.
It is recently appreciated that many bacterial chemoreceptors have ligand-binding domains (LBD) of the dCACHE family, a structure with two PAS-like subdomains, one membrane-proximal and the other ...membrane-distal. Previous studies had implicated only the membrane-distal subdomain in ligand recognition. Here, we report the 2.2 Å resolution crystal structure of dCACHE LBD of the Helicobacter pylori chemoreceptor TlpC. H. pylori tlpC mutants are outcompeted by wild type during stomach colonisation, but no ligands had been mapped to this receptor. The TlpC dCACHE LBD has two PAS-like subdomains, as predicted. The membrane-distal one possesses a long groove instead of a small, well-defined pocket. The membrane-proximal subdomain, in contrast, had a well-delineated pocket with a small molecule that we identified as lactate. We confirmed that amino acid residues making contact with the ligand in the crystal structure-N213, I218 and Y285 and Y249-were required for lactate binding. We determined that lactate is an H. pylori chemoattractant that is sensed via TlpC with a K
= 155 µM. Lactate is utilised by H. pylori, and our work suggests that this pathogen seeks out lactate using chemotaxis. Furthermore, our work suggests that dCACHE domain proteins can utilise both subdomains for ligand recognition.
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