Distinct Disease Phenotypes Research Articles

Cellular Mechanisms of RET Receptor Dysfunction in Multiple Endocrine Neoplasia 2.

REarranged during Transfection (RET) is a developmentally important receptor tyrosine kinase that has been identified as an oncogenic driver in a number of cancers. Activating RET point-mutations give rise to the inherited cancer syndrome Multiple Endocrine Neoplasia type 2 (MEN2), characterized by medullary thyroid carcinoma. There are two MEN2 subtypes, MEN2A and MEN2B, that differ in tumour aggressiveness and the associated constellation of other disease features, which are caused by distinct patterns of RET amino acid substitution mutations. MEN2A-RET mutations affecting extracellular cysteine residues promote ligand independent dimerization and constitutive RET activity, while MEN2B is caused by a single amino acid change in the tyrosine kinase domain of RET, releasing autoinhibition and producing a more active MEN2B-RET kinase that can promote signalling as monomers or dimers in the absence of ligand. These mutations cause intrinsic biochemical changes in RET structure and activation but also trigger extrinsic effects that alter RET cellular location, interactions and mechanisms of downregulation that can prolong or mislocate RET activity, changing or enhancing functional outcomes. Together, changes in specific combinations of RET-mediated effects associated with different mutations give rise to the distinct MEN2 disease phenotypes. Here, we discuss the current understanding of the intrinsic and extrinsic characteristics of RET MEN2A cysteine and MEN2B mutants and how these contribute to transforming cellular processes and to differences in tumour progression and disease aggressiveness.

α-Synuclein strain propagation is independent of cellular prion protein expression in a transgenic synucleinopathy mouse model.

The cellular prion protein, PrPC, has been postulated to function as a receptor for α-synuclein, potentially facilitating cell-to-cell spreading and/or toxicity of α-synuclein aggregates in neurodegenerative disorders such as Parkinson's disease. Previously, we generated the "Salt (S)" and "No Salt (NS)" strains of α-synuclein aggregates that cause distinct pathological phenotypes in M83 transgenic mice overexpressing A53T-mutant human α-synuclein. To test the hypothesis that PrPC facilitates the propagation of α-synuclein aggregates, we produced M83 mice that either express or do not express PrPC. Following intracerebral inoculation with the S or NS strain, the absence of PrPC in M83 mice did not prevent disease development and had minimal influence on α-synuclein strain-specified attributes such as the extent of cerebral α-synuclein deposition, selective targeting of specific brain regions and cell types, the morphology of induced α-synuclein deposits, and the structural fingerprints of protease-resistant α-synuclein aggregates. Likewise, there were no appreciable differences in disease manifestation between PrPC-expressing and PrPC-lacking M83 mice following intraperitoneal inoculation of the S strain. Interestingly, intraperitoneal inoculation with the NS strain resulted in two distinct disease phenotypes, indicative of α-synuclein strain evolution, but this was also independent of PrPC expression. Overall, these results suggest that PrPC plays at most a minor role in the propagation, neuroinvasion, and evolution of α-synuclein strains in mice that express A53T-mutant human α-synuclein. Thus, other putative receptors or cell-to-cell propagation mechanisms may have a larger effect on the spread of α-synuclein aggregates during disease.

Differential HBV replicative markers and covalently closed circular DNA transcription in immune-active chronic hepatitis B with and without HBeAg.

Molecular processes driving immune-active chronic hepatitis B (CHB) with and without hepatitis B e antigen (HBeAg) remain incompletely understood. This study aimed to investigate expression profiles of serum and intrahepatic HBV markers and replicative activity of HBV in CHB patients with or without HBeAg. This study recruited 111 untreated immune-active CHB (60 HBeAg-positive and 51 HBeAg-negative) patients and quantified intrahepatic covalently closed circular DNA (cccDNA), pre-genomic RNA (pgRNA), total HBV DNA (tDNA), and replicative intermediates as well as serum HBV markers (HBV DNA, hepatitis B surface antigen, hepatitis B core-related antigen). Correlations between HBV markers and clinico-virological factors influencing expression levels of HBV markers were analysed. Levels of all serum markers and intrahepatic cccDNA/tDNA as well as cccDNA transcriptional activity and virion productivity were significantly reduced in HBeAg-negative patients compared to those in HBeAg-positive patients. Additionally, correlations between intrahepatic cccDNA/pgRNA and serum markers were impaired in HBeAg-negative individuals. Aminotransferase levels were positively correlated with cccDNA transcriptional activity in HBeAg-positive patients, but not in HBeAg-negative patients. Notably, among HBeAg-positive patients, there was a progressive decline in pgRNA level, transcriptional activity, and serum HBV markers as liver fibrosis advanced, which was not observed in HBeAg-negative patients. HBeAg loss is correlated with diminished intrahepatic HBV reservoirs and cccDNA transcription, leading to decreased serum HBV marker levels. Circulating HBV markers are not reliable indicators of intrahepatic HBV replicative activity for HBeAg-negative patients. Our findings reveal distinct disease phenotypes between immune-active CHB with and without HBeAg, highlighting the need to establish optimal surrogate biomarkers that can accurately mirror intrahepatic viral activity to aid in decision-making for antiviral therapy for immune-active CHB.

Cystic fibrosis cell models for high-throughput analysis and drug screening

Cystic fibrosis (CF) is a single-gene disorder that affects the lung, digestive system, and other organs. Mutations in the CF transmembrane conductance regulator (CFTR) gene are classified into several classes based on their pathogenic mechanism and clinical severity. The distinct and heterogeneous clinical behavior of each CF class and the respective CFTR mutations have made the development of a durable therapy for all CF patients extremely challenging. While the FDA-approved drug elexacaftor/tezacaftor/ivacaftor (Trikafta) benefits CF patients carrying at least one F508del mutation in CFTR, it's not effective for many CF patients carrying a variety of other CFTR mutations. To establish a better understanding of CF pathophysiology and aid the development of novel therapeutics for different classes of CF patients, we have created four CF-mutation-specific cell models that recapitulate respectively four distinct CF classes and disease phenotypes, as confirmed by sequencing, CFTR mRNA and protein quantification. The channel function of each cell model was first validated using a well-established FLIPR (Fluorescent Imaging Plate Reader) membrane potential assay and then assessed by the YFP-based functional assay. Integrated with a halide-sensitive fluorescent reporter, these CF cell models can be used for high-throughput drug screening, as demonstrated by a proof-of-concept study using Trikafta. These cell models have the potential to advance CFTR mutation-specific therapies thus addressing the unmet needs of CF patients with rare mutations.

Validation of a non-food or water motivated effort-based foraging task as a measure of motivational state in male mice

Disorders of motivation such as apathy syndrome are highly prevalent across neurological disorders but do not yet have an agreed treatment approach. The use of translational behavioural models can provide a route through which to meaningfully screen novel drug targets. Methods that utilise food deprivation in contrived environments may lack the sensitivity to detect deficits in self-initiated behaviour, and may have limited translation to normal behaviour. Animals monitored in more naturalistic environments may display more ethologically-relevant behaviours of greater translational value. Here, we aimed to validate a novel, non-food or water motivated effort-based foraging task as a measure of motivational state in mice. In this task, the mouse can freely choose to exert effort to forage nesting material and shuttle it back to a safe and enclosed environment. The amount of nesting material foraged is used as a readout of motivational state. Acute dopaminergic modulation with haloperidol, amphetamine and methylphenidate, and two phenotypic models known to induce motivational deficits (healthy ageing and chronic administration of corticosterone) were used to validate this task. Consistent with other effort-based decision-making tasks we find that foraging behaviour is sensitive to acute modulation of dopaminergic transmission. We find that both phenotypic models induce differing deficits in various aspects of foraging behaviour suggesting that the task may be used to parse different behavioural profiles from distinct disease phenotypes. Thus, without requiring extended training periods or physiological deprivation, this task may represent a refined and translational preclinical measure of motivation.

Interferon and B-cell Signatures Inform Precision Medicine in Lupus Nephritis

IntroductionCurrent therapeutic management of lupus nephritis (LN) fails to induce long-term remission in over 50% of patients, highlighting the urgent need for additional options. MethodsWe analysed differentially expressed genes in peripheral blood from active LN (n=41) and active non-renal lupus (n=62) patients versus healthy controls (n=497) from the European PRECISESADS project (NTC02890121), and dysregulated gene modules in a discovery (n=26) and a replication (n=15) set of active LN cases. ResultsReplicated gene modules qualified for correlation analyses with serological markers, and regulatory network and druggability analysis. Unsupervised co-expression network analysis revealed 20 dysregulated gene modules and stratified the active LN population into three distinct subgroups. These subgroups were characterised by low, intermediate, and high interferon (IFN) signatures, with differential dysregulation of the “B cell” and “plasma cells/immunoglobulins” modules. Drugs annotated to the IFN network included CC-motif chemokine receptor 1 inhibitors, programmed death-ligand 1 inhibitors, and irinotecan, while the anti-CD38 daratumumab and proteasome inhibitor bortezomib showed potential for counteracting the “plasma cells/immunoglobulins” transcriptomic signature. In silico analysis demonstrated the low-IFN subgroup to benefit from calcineurin inhibition and the intermediate-IFN subgroup from B cell targeted therapies. High-IFN patients exhibited greater anticipated response to anifrolumab while daratumumab appeared beneficial for the intermediate-IFN and high-IFN subgroups. ConclusionIn summary, IFN upregulation and B and plasma cell gene dysregulation patterns revealed three LN patient subgroups, which may not necessarily represent distinct disease phenotypes but rather phases of the inflammatory processes during a renal flare, providing a conceptual framework for precision medicine in LN.

Exploring Future Horizons in Osteoarthritis Relief: Unveiling the Potential of Slow-Acting Drugs and Innovative Medications

Introduction: 
 The existing treatment options for osteoarthritis (OA) fall short of addressing the significant challenges this disease imposes on patients in today's society. It markedly diminishes the quality of life of those affected and is one of the leading causes of disability. While conventional pharmacological interventions such as non-steroidal anti-inflammatory drugs (NSAIDs) and opioids effectively address pain, they are not intended to halt disease progression and are associated with potential health risks. Symptomatic Slow-Acting Drugs for Osteoarthritis (SYSADOA) and innovative medications, rooted in our expanding understanding of OA pathogenesis, offer promising prospects for discovering improved treatment modalities.
 
 State of knowledge: 
 The evolving understanding of OA's etiology highlights the necessity for tailored treatments that consider distinct disease phenotypes. This review critically examines SYSADOA, specifically focusing on chondroitin sulfate, glucosamine, and avocado-soybean unsaponifiables, as agents designed to address the underlying pathology of OA. Chondroitin sulfate demonstrates potential disease-modifying effects, however with conflicting study results that underscore the extent of its efficacy. Glucosamine exhibits varying disease-modifying effects, with short-term trials demonstrating more promising outcomes in pain reduction. Avocado-soybean unsaponifiables show promise in alleviating knee OA pain, yet their impact on hip OA symptoms remains inconclusive. The review extends its scope to novel drugs with potential disease-modifying effects, exploring proteinase inhibitors, fibroblast growth factors, Wnt-signaling pathway inhibitors, senolytic agents, anti-nerve growth factor agents, and transforming growth factor-β.
 
 Conclusions: 
 Although preliminary studies indicate potential for certain novel agents, challenges and adverse effects necessitate further investigation through rigorous, high-quality research.

INFECTIOUS COMPLICATIONS IN PATIENTS WITH PRIMARY SCLEROSING CHOLANGITIS AND INFLAMMATORY BOWEL DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract BACKGROUND Primary sclerosing cholangitis (PSC) is a cholestatic immune-mediated liver disease that can be associated with inflammatory bowel disease (IBD) in up to 80% of patients. Those with concurrent PSC-IBD exhibit a distinct disease phenotype with increased risk of complications such as malignancy and pouchitis; however, the risk of infections is not yet clearly defined in this population. AIMS The aims of this systematic review and meta-analysis are (1) to determine the incidence of infections in patients with PSC-IBD and (2) to identify risk factors for infections in this population. METHODS MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception to March 24, 2022 for primary studies that reported incidence or risk factors for infection in adult and pediatric patients with PSC and IBD. Case reports and case series with less than five patients were excluded, as were any studies where infection rates in PSC-IBD patients could not be separated from those with PSC or IBD alone. The primary outcome of this study was incidence of all-cause infections including bacterial, viral, or fungal infections, and sepsis. The secondary outcomes included incidence of site-specific infections and mortality due to infection. A random-effects model was used to calculate pooled odds ratios (OR) with 95% confidence intervals (CI) comparing incidence of all-cause infections in PSC-IBD to those with PSC alone or IBD alone. RESULTS Seventy-one studies were included. The pooled incidence of all-cause infections in patients with PSC-IBD was 21.8% (95% CI 0.17-0.26, I2=95.9%), 31.1% (95% CI 0.16-0.46, I2=93.4%) in those with PSC alone, and 4.4% (95% CI -0.01-0.10, I2=99.2%) in those with IBD alone. Patients with PSC-IBD had an over three-fold increased odds of all-cause infection compared to those with isolated IBD (OR 3.67, 95% CI 2.07-6.50). Patients with PSC-IBD were more likely to develop sepsis (OR 3.35, 95% CI 2.29-4.90) and have infections resulting in mortality (OR 11.25, 95% CI 2.03-62.37) compared to those with IBD. The most common infections in the PSC-IBD group were sepsis followed by clostridioides difficile infection. There was no significant difference in the odds of infection between patients with PSC-IBD and those with PSC alone (OR 1.21, 95% CI 0.68-2.18). However, on sub-group analysis, patients with PSC-IBD undergoing liver transplantation (LT) were more likely to develop infection post-LT compared to those with PSC alone (OR 4.86, 95% CI, 2.32-10.17), with cytomegalovirus (CMV) being the most commonly reported infection. CONCLUSION Compared to those with IBD, patients with PSC-IBD appear to be at a higher risk of infection and resultant complications such as sepsis and death. Future studies are needed to elucidate specific risk factors such as immunosuppressive therapy and disease activity.

P522 Post hoc analysis reveals limited efficacy of induction therapy in ileum only Crohn´s disease

Abstract Background Crohn´s disease (CD) can affect any part of the GI tract, although has a predilection for the terminal ileum and colon. Approximately 30% of patients have inflammation restricted to the small intestine, another 30% have disease limited to the colon, and the remainder have a combination of small and large bowel involvement. Despite studies suggesting that ileal and colonic CD may be distinct disease phenotypes and might therefore respond differently to treatment, CD patients are typically enrolled into clinical trials irrespective of the site of gastrointestinal involvement. The aim of this systematic review and meta-analysis was to assess treatment efficacy in patients with small bowel disease. Methods Embase and PubMed databases were searched until October 2023 for randomised, placebo-controlled, clinical trials that reported induction efficacy, based on clinical remission (CDAI <150), in ileal-only Crohn’s disease between 2010 and 2023. The following search criteria were employed: Crohn´s disease AND [2010-2023] AND (small bowel OR ileum OR ileal OR L1) AND (CDAI OR clinical remission AND induction AND placebo). Additional studies, not identified through this search strategy were also considered. Resultant studies were systematically reviewed before a random-effects meta-analysis was undertaken to assess induction efficacy, based on clinical remission, in ileal only CD. Results A total of 9 studies, involving 709 adult patients, were identified: two via Embase and PubMed; six from supplementary search materials; and one post-hoc analysis of brazikumab data (not published). The studies provided CDAI remission results by disease location subset. The induction treatment times ranged from 6-12 weeks, and both bio-naïve and bio-failure patients were included. The studies were relatively homogenous (I2 = 38.5%, Q = 13.0 (p-value = 0.112)) with a random effect meta-analytic estimate of difference versus placebo in CDAI remission of 2.1% (95% CI -6% to 11%). Two studies used clinical response (defined as ≥ 100 point decrease or score < 150) as indicated in the figure. Conclusion This is the first systematic meta-analysis of treatment effects in ileal-only CD. The available evidence suggests treatment effect heterogeneity, with inferior outcomes in ileal disease versus a broader patient population with ileocolonic or colonic involvement. Previous systematic review1 on clinical remission after induction treatment demonstrate placebo adjusted values in the range of 12-20% in a no defined disease site population. This indicates the need for novel therapies with a mechanism of action directly tailored to heal the small intestine in patients with CD.

Detection and Characterization of Xylella fastidiosa subsp. fastidiosa in Rabbiteye Blueberry in South Carolina.

Xylella fastidiosa causes bacterial leaf scorch in southern highbush (Vaccinium corymbosum interspecific hybrids) and is also associated with a distinct disease phenotype in rabbiteye blueberry (V. virgatum) cultivars in the southeastern United States. Both X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. multiplex have been reported to cause problems in southern highbush blueberry, but so far only X. fastidiosa subsp. multiplex has been reported in rabbiteye cultivars in Louisiana. In this study, we report detection of X. fastidiosa in rabbiteye blueberry plants in association with symptoms of foliar reddening and shoot dieback. High throughput sequencing of an X. fastidiosa-positive plant sample and comparative analyses identified the strain in one of these plants as being X. fastidiosa subsp. fastidiosa. We briefly discuss the implications of these findings, which may spur research into blueberry as a potential inoculum source that could enable spread to other susceptible fruit crops in South Carolina.

Molecular characterization of the circadian clock in patients with Parkinson's disease-CLOCK4PD Study protocol.

Circadian rhythms (CRs) orchestrate intrinsic 24-hour oscillations which synchronize an organism's physiology and behaviour with respect to daily cycles. CR disruptions have been linked to Parkinson's Disease (PD), the second most prevalent neurodegenerative disorder globally, and are associated to several PD-symptoms such as sleep disturbances. Studying molecular changes of CR offers a potential avenue for unravelling novel insights into the PD progression, symptoms, and can be further used for optimization of treatment strategies. Yet, a comprehensive characterization of the alterations at the molecular expression level for core-clock and clock-controlled genes in PD is still missing. The proposed study protocol will be used to characterize expression profiles of circadian genes obtained from saliva samples in PD patients and controls. For this purpose, 20 healthy controls and 70 PD patients will be recruited. Data from clinical assessment, questionnaires, actigraphy tracking and polysomnography will be collected and clinical evaluations will be repeated as a follow-up in one-year time. We plan to carry out sub-group analyses considering several clinical factors (e.g., biological sex, treatment dosages, or fluctuation of symptoms), and to correlate reflected changes in CR of measured genes with distinct PD phenotypes (diffuse malignant and mild/motor-predominant). Additionally, using NanoStringⓇ multiplex technology on a subset of samples, we aim to further explore potential CR alterations in hundreds of genes involved in neuropathology pathways. CLOCK4PD is a mono-centric, non-interventional observational study aiming at the molecular characterization of CR alterations in PD. We further plan to determine physiological modifications in sleep and activity patterns, and clinical factors correlating with the observed CR changes. Our study may provide valuable insights into the intricate interplay between CR and PD with a potential to be used as a predictor of circadian alterations reflecting distinct disease phenotypes, symptoms, and progression outcomes.

A Knowledge Graph Approach to Elucidate the Role of Organellar Pathways in Disease via Biomedical Reports.

The rapidly increasing and vast quantities of biomedical reports, each containing numerous entities and rich information, represent a rich resource for biomedical text-mining applications. These tools enable investigators to integrate, conceptualize, and translate these discoveries to uncover new insights into disease pathology and therapeutics. In this protocol, we present CaseOLAP LIFT, a new computational pipeline to investigate cellular components and their disease associations by extracting user-selected information from text datasets (e.g., biomedical literature). The software identifies sub-cellular proteins and their functional partners within disease-relevant documents. Additional disease-relevant documents are identified via the software's label imputation method. To contextualize the resulting protein-disease associations and to integrate information from multiple relevant biomedical resources, a knowledge graph is automatically constructed for further analyses. We present one use case with a corpus of ~34 million text documents downloaded online to provide an example of elucidating the role of mitochondrial proteins in distinct cardiovascular disease phenotypes using this method. Furthermore, a deep learning model was applied to the resulting knowledge graph to predict previously unreported relationships between proteins and disease, resulting in 1,583 associations with predicted probabilities >0.90 and with an area under the receiver operating characteristic curve (AUROC) of 0.91 on the test set. This software features a highly customizable and automated workflow, with a broad scope of raw data available for analysis; therefore, using this method, protein-disease associations can be identified with enhanced reliability within a text corpus.

OR20-02 Trans-Ethnic Analysis Of PCOS Subtype Genomewide Association Signals Reveals 3 Shared Subtype-Specific Loci

Abstract Disclosure: K. Brewer: None. R. Sisk: None. H. Lee: None. L.M. Moolhuijsen: None. K. van der Ham: None. Y. Louwers: None. J.A. Visser: None. M. Dapas: None. S. Franks: None. J.S. Laven: None. C. Li: None. A.E. Dunaif: None. The phenotypic variation observed in PCOS is suggestive of underlying genetic heterogeneity, but a recent meta-analysis of European ancestry (EA) PCOS cases found that the genetic architecture of PCOS defined by NIH and Rotterdam diagnostic criteria was similar, suggesting that these criteria do not identify biologically distinct disease phenotypes. Using Hierarchical Clustering (HC) in EA NIH PCOS cases, we have identified discrete, stable PCOS subtypes, which we called reproductive and metabolic (Dapas. PLoS Med, 2020); cases that did not cluster were designated as “background”. These subtypes appeared to capture biologically meaningful differences because they were associated with distinct genomewide significant loci. We were unable to replicate 4 of 6 loci since the lead SNPs were neither genotyped nor imputed on the array used for replication, the Metabochip custom array for cardiometabolic traits with additional PCOS-relevant SNPs. Here, we report an updated EA genomewide association study (GWAS) meta-analysis with additional EA NIH PCOS cases, and a trans-ethnic meta-analysis including a Korean ancestry (KA) NIH PCOS cohort (Lee. Hum Reprod, 2015). HC was applied to cases in both cohorts to identify PCOS subtypes. The EA discovery cohort, 620 cases and 2951 controls, was genotyped with the Illumina OmniExpress array. The replication EA cohort, 371 cases and 926 controls, was genotyped with the Metabochip. The KA cohort, 417 cases and 926 controls, was genotyped with the HumanOmni1-Quad v1 array. The imputation of previously reported genotype data was updated using the larger, more deeply sequenced TOPMed (R2) imputation panel. Nine loci were genomewide significant in the EA meta-analysis: 5 novel loci (reproductive subtype); 2 loci (metabolic subtype), including c9orf3; 2 loci (background subtype), including FSHB/ARL14P. Five of 6 other lead SNPs in the original analysis remained nominally significant. Three loci were significant in the trans-ethnic meta-analysis: a novel locus on chr 3, EPHA6, a receptor tyrosine kinase that binds promiscuously GPI-anchored ephrin-A family ligands (rs140766105, p=1.08 x 10-8, reproductive subtype); a previously identified GWAS locus on chr 9, c9orf3 (AOPEP), an aminopeptidase that catalyzes the hydrolysis of amino acid residues from the N-terminus of peptides (rs10761370, p=4.12 x 10-9, metabolic subtype); a previously identified GWAS locus on chr 11, FSHB/ARL14P, FSHB encodes the β-subunit of FSH and is associated with general fertility status, (rs10835649, 1.23 x 10-11, background subtype). We have replicated the 9 distinct subtype loci in the EA meta-analysis providing orthogonal (independent) validation suggesting these subtypes have distinct genetic architecture. For the first time, a trans-ethnic meta-analysis demonstrates that 3 subtype-specific loci play a role in PCOS pathogenesis across diverse populations. Presentation Date: Saturday, June 17, 2023

Does Chronic Obstructive Pulmonary Disease Originate from Different Cell Types?

The onset of chronic obstructive pulmonary disease (COPD) is heterogeneous, and current approaches to define distinct disease phenotypes are lacking. In addition to clinical methodologies, subtyping COPD has also been challenged by the reliance on human lung samples from late-stage diseases. Different COPD phenotypes may be initiated from the susceptibility of different cell types to cigarette smoke, environmental pollution, and infections at early stages that ultimately converge at later stages in airway remodeling and destruction of the alveoli when the disease is diagnosed. This perspective provides discussion points on how studies to date define different cell types of the lung that can initiate COPD pathogenesis, focusing on the susceptibility of macrophages, T and B cells, mast cells, dendritic cells, endothelial cells, and airway epithelial cells. Additional cell types, including fibroblasts, smooth muscle cells, neuronal cells, and other rare cell types not covered here, may also play a role in orchestrating COPD. Here, we discuss current knowledge gaps, such as which cell types drive distinct disease phenotypes and/or stages of the disease and which cells are primarily affected by the genetic variants identified by whole genome-wide association studies. Applying new technologies that interrogate the functional role of a specific cell type or a combination of cell types as well as single-cell transcriptomics and proteomic approaches are creating new opportunities to understand and clarify the pathophysiology and thereby the clinical heterogeneity of COPD.

Non-micellar ganglioside GM1 induces an instantaneous conformational change in Aβ42 leading to the modulation of the peptide amyloid-fibril pathway

Alzheimer's disease is a progressive degenerative condition that mainly affects cognition and memory. Recently, distinct clinical and neuropathological phenotypes have been identified in AD. Studies revealed that structural variation in Aβ fibrillar aggregates correlates with distinct disease phenotypes. Moreover, environmental surroundings, including other biomolecules such as proteins and lipids, have been shown to interact and modulate Aβ aggregation. Model membranes containing ganglioside (GM1) clusters are specifically known to promote Aβ fibrillogenesis. This study unravels the modulatory effect of non-micellar GM1, a glycosphingolipid frequently released from the damaged neuronal membranes, on Aβ42 amyloid fibril formation. Using far-UV circular dichroism experiments, we observed a change in the peptide secondary structure from random-coil to β-turn structures with subsequent generation of predominantly β-sheet-rich species upon interaction with GM1. Thioflavin-T (ThT) fluorescence assays further indicated that GM1 likely interacts with an amyloidogenic Aβ42 intermediate species leading to a possible formation of GM1-modified Aβ42 fibril. Statistically, no significant difference in toxicity to RA-differentiated SH-SY5Y cells was observed between Aβ42 fibrils and GM1-tweaked Aβ42 aggregates. Moreover, GM1-modified Aβ42 aggregates exhibited prion-like properties in catalyzing the amyloid fibril formation of both major isomers of Aβ, Aβ40, and Aβ42.

Modeling of mitochondrial genetic polymorphisms reveals induction of heteroplasmy by pleiotropic disease locus 10398A>G

Mitochondrial (MT) dysfunction has been associated with several neurodegenerative diseases including Alzheimer’s disease (AD). While MT-copy number differences have been implicated in AD, the effect of MT heteroplasmy on AD has not been well characterized. Here, we analyzed over 1800 whole genome sequencing data from four AD cohorts in seven different tissue types to determine the extent of MT heteroplasmy present. While MT heteroplasmy was present throughout the entire MT genome for blood samples, we detected MT heteroplasmy only within the MT control region for brain samples. We observed that an MT variant 10398A>G (rs2853826) was significantly associated with overall MT heteroplasmy in brain tissue while also being linked with the largest number of distinct disease phenotypes of all annotated MT variants in MitoMap. Using gene-expression data from our brain samples, our modeling discovered several gene networks involved in mitochondrial respiratory chain and Complex I function associated with 10398A>G. The variant was also found to be an expression quantitative trait loci (eQTL) for the gene MT-ND3. We further characterized the effect of 10398A>G by phenotyping a population of lymphoblastoid cell-lines (LCLs) with and without the variant allele. Examination of RNA sequence data from these LCLs reveal that 10398A>G was an eQTL for MT-ND4. We also observed in LCLs that 10398A>G was significantly associated with overall MT heteroplasmy within the MT control region, confirming the initial findings observed in post-mortem brain tissue. These results provide novel evidence linking MT SNPs with MT heteroplasmy and open novel avenues for the investigation of pathomechanisms that are driven by this pleiotropic disease associated loci.

The Incidence of IgG4-Related and Inflammatory Abdominal Aortic Aneurysm Is Rare in a 101 Patient Cohort.

Abdominal aortic aneurysms (AAA) are the most frequent aortic dilation, with considerable morbidity and mortality. Inflammatory (infl) and IgG4-positive AAAs represent specific subtypes of unclear incidence and clinical significance. Here, histologic and serologic analyses with retrospective clinical data acquisition are investigated via detailed histology, including morphologic (HE, EvG: inflammatory subtype, angiogenesis, and fibrosis) and immunhistochemic analyses (IgG and IgG4). In addition, complement factors C3/C4 and immunoglobulins IgG, IgG2, IgG4 and IgE were measured in serum samples and clinical data uses patients' metrics, as well as through semi-automated morphometric analysis (diameter, volume, angulation and vessel tortuosity). A total of 101 eligible patients showed five (5%) IgG4 positive (all scored 1) and seven (7%) inflammatory AAAs. An increased degree of inflammation was seen in IgG4 positive and inflAAA, respectively. However, serologic analysis revealed no increased levels of IgG or IgG4. The operative procedure time was not different for those cases and the short-term clinical outcomes were equal for the entire AAA cohort. Overall, the incidence of inflammatory and IgG4-positive AAA samples seems very low based on histologic and serum analyses. Both entities must be considered distinct disease phenotypes. Short-term operative outcomes were not different for both sub-cohorts.

Sex Differences in Clinical Manifestations of Hospitalized Patients With Eosinophilic Granulomatosis With Polyangiitis: A Retrospective Cohort Study.

To investigate the effect of sex on the clinical characteristics, prognoses, and therapeutic selection of eosinophilic granulomatosis with polyangiitis (EGPA). We retrospectively enrolled 170 hospitalized patients with EGPA who were managed at our hospital between 2007 and 2020. Detailed clinical data were reviewed. Manifestations, prognoses, treatments, and outcomes were compared between female and male patients. Cumulative survival rates were calculated using Kaplan-Meier curves. In this cohort, the male to female ratio was 1.4:1. Renal involvement was more frequent in male patients, including serum creatinine elevation, and proteinuria > 1 g/24 h. Severe gastrointestinal (GI) involvement occurred more commonly in male patients. Female patients had longer allergy duration and higher ratios of allergic rhinitis and asthma. Sex differences in proteinuria > 1 g/24 h, serum creatinine > 150 mmol/L, severe GI involvement, and weight loss were more significant in patients aged ≤ 55 years than those in patients aged > 55 years. Overall, male patients had a higher Birmingham Vasculitis Activity Score and a worse prognosis assessed at diagnosis, with a lower proportion of 1996 Five Factor Score = 0 than females. Regarding treatment selection, methylprednisolone pulse and cyclophosphamide were administered more frequently to male patients. All-cause mortality and cumulative survival rates were comparable between the sexes. In this Chinese EGPA cohort, male and female patients showed distinct disease phenotypes. Male patients with EGPA had a higher disease activity at diagnosis and required more aggressive treatment for remission induction.

Human OTULIN mutations can cause distinct inflammatory disease phenotypes depending on the protein domain that is mutated

Abstract Linear ubiquitination is a post-translational modification that controls many immune signaling pathways. Linear ubiquitin chains are added to targets by LUBAC and removed by OTULIN, thus the opposing actions of LUBAC and OTULIN are critical for immune homeostasis. To understand mechanisms of how ubiquitination controls inflammation, we leveraged the use of biospecimens from patients with a novel bi-allelic OTULIN mutation. These patients have pyoderma gangrenosum (PG), an extremely rare inflammatory skin disease. OTULIN mutations have been previously described to cause a systemic autoinflammatory disease called ORAS, yet these patients define a new monogenic disease. We sought to understand this discrepancy through functional analyses of OTULIN mutations that culminate in PG vs ORAS. ORAS-causing OTULIN mutations impair the catalytic domain. However, the mutation in PG patients affects the domain responsible for binding LUBAC. Further, OTULIN’s ability to downregulate linear ubiquitin or NF-kB activity was unaffected. Patients’ transcriptional signatures showed elevated expression of genes involved in neutrophil activation and antigen presentation, and reduced expression of genes involved in Th17 differentiation, TLR signaling, and NOD-like receptor signaling. Deep immunophenotyping by CyTOF revealed that PG patients have higher frequencies of T cells and subtle defects of B cells and myeloid cells. These patients’ unique phenotype suggests an unrecognized function for OTULIN in skin inflammation. This discovery adds to the emerging spectrum of human immune-mediated diseases caused by defects in the ubiquitin pathway.

Prevalence and clinical associations of ultrasound-confirmed enthesitis in systemic lupus erythematosus.

To assess the prevalence of ultrasound (US)-confirmed enthesitis in a cohort of patients with systemic lupus erythematosus (SLE) and to analyze the clinical associations to enthesitis during the course of SLE. In a retrospective analysis of the SLE cohort of the Lupus Unit of the Careggi University Hospital, US examinations of SLE patients presenting with tender and/or swollen joints were retrieved to assess the presence of enthesitis. Patients with US-proven enthesitis were compared with SLE controls with tender and/or swollen joints who showed no US-evidence of enthesitis. Clinical and laboratory features were compared at disease onset and during follow-up. A total of 400 patients fulfilling EULAR/ACR classification criteria for SLE were assessed. Of them, 106 underwent articular US examination. Evidence of enthesitis was found in 31/106 (29.2%) patients. Seventy-one patients without US-enthesitis were included as controls, 4 were excluded due to lack of follow-up data. Laboratory and clinical features were comparable between cases and controls at disease onset. Throughout a median follow-up of 10.0 (IQR 8.3-23.3) years for cases and 12.4 (IQR 7.2-13.3) years for controls, patients with enthesitis were less likely to develop renal involvement (22.6% vs 46.5%, p= 0.028) and failed B cell depletion more frequently (75.0% vs 0%). In SLE patients with clinically active joints, US-proven enthesitis is a fairly common finding. Enthesitis in SLE could be the hallmark of a distinct disease phenotype with less renal involvement, more arthritis, and low response to anti-CD 20 therapy, potentially requiring a tailored treatment.