Heterozygous RTN2 variants have been previously identified in a limited cohort of families affected by autosomal dominant spastic paraplegia (SPG12-OMIM:604805) with a variable age of onset. Nevertheless, the definitive validity of SPG12 remains to be confidently confirmed due to scarcity of supporting evidence. In our study, we identified and validated seven novel or ultra-rare homozygous loss-of-function RTN2 variants in 14 individuals from seven consanguineous families with distal hereditary motor neuropathy (dHMN) using exome, genome and Sanger sequencing coupled with deep-phenotyping. All affected individuals (seven males and seven females, aged 9-50 years) exhibited weakness in the distal upper and lower limbs, lower limb spasticity, hyperreflexia, with an onset in the first decade of life. Nerve conduction studies revealed axonal motor neuropathy with neurogenic changes in the electromyography. Despite a slowly progressive disease course, all patients remained ambulatory over a mean disease duration of 19.71 ± 13.70 years. Characterisation of C. elegans RTN2 homolog loss-of-function variants demonstrated morphological and behavioural differences compared to the parental strain. Treatment of the mutant with an endoplasmic/sarcoplasmic reticulum Ca2+ reuptake inhibitor (2,5-di-tert-butylhydroquinone) rescued key phenotypic differences, suggesting a potential therapeutic benefit for RTN2-disorder. Despite Reticulon-2 being an endoplasmic reticulum (ER)-resident membrane shaping protein, our analysis of patient fibroblast cells did not find significant alterations in ER structure or the response to ER stress. Our findings delineate a distinct form of autosomal recessive dHMN with pyramidal features associated with Reticulon-2 deficiency. This phenotype shares similarities with SIGMAR1-related dHMN, and Silver-like syndromes, providing valuable insights into the clinical spectrum and potential therapeutic strategies for RTN2-related dHMN.

Murine norovirus (MNV) undergoes extremely large conformational changes in response to the environment. The = 3 icosahedral capsid is composed of 180 copies of ~58-kDa VP1 comprised of N-terminus (N), shell (S), and C-terminal protruding (P) domains. At neutral pH, the P domains are loosely tethered to the shell and float ~15 Å above the surface. At low pH or in the presence of bile salts, the P domain drops onto the shell and this movement is accompanied by conformational changes within the P domain that enhance receptor interactions while blocking antibody binding. While previous crystallographic studies identified metal binding sites in the isolated P domain, the ~2.7-Å cryo-electron microscopy structures of MNV in the presence of Mg or Ca presented here show that metal ions can recapitulate the contraction observed at low pH or in the presence of bile. Further, we show that these conformational changes are reversed by dialysis against EDTA. As observed in the P domain crystal structures, metal ions bind to and contract the G'H' loop. This movement is correlated with the lifting of the C'D' loop and rotation of the P domain dimers about each other, exposing the bile salt binding pocket. Isothermal titration calorimetry experiments presented here demonstrate that the activation signals (bile salts, low pH, and metal ions) act in a synergistic manner that, individually, all result in the same activated structure. We present a model whereby these reversible conformational changes represent a uniquely dynamic and tissue-specific structural adaptation to the environment.IMPORTANCEThe highly mobile protruding domains on the calicivirus capsids are recognized by cell receptor(s) and antibodies. At neutral pH, they float ~15 Å above the shell but at low pH or in the presence of bile salts, they contract onto the surface. Concomitantly, changes within the P domain block antibody binding while enhancing receptor binding. While we previously demonstrated that metals also block antibody binding, it was unknown whether they might also cause similar conformational changes in the virion. Here, we present the near atomic cryo-electron microscopy structures of infectious murine norovirus (MNV) in the presence of calcium or magnesium ions. The metal ions reversibly induce the same P domain contraction as low pH and bile salts and act in a synergistic manner with the other stimuli. We propose that, unlike most other viruses, MNV facilely changes conformations as a unique means to escape immune surveillance as it moves through various tissues.

OBJECTIVE: Inflammation has been associated with an increased risk for cancer development, while innate immune system activation could counteract the risk for malignancies. Familial Mediterranean fever (FMF) is a severe systemic inflammatory condition and also represents the archetype of innate immunity deregulation. Therefore, the aim of this study is to investigate the risk for cancer development in FMF.

METHODS: The risk ratio (RR) for malignancies was separately compared between FMF patients and fibromyalgia subjects, Still's disease patients and Behçet's disease patients. Clinical variables associated with cancer development in FMF patients were searched through binary logistic regression.

RESULTS: 580 FMF patients and 102 fibromyalgia subjects, 1012 Behçet's disease patients and 497 Still's disease patients were enrolled. The RR for the occurrence of malignant neoplasms was 0.26 (95% Confidence Interval [CI.] 0.10-0.73, p=0.006) in patients with FMF compared to fibromyalgia subjects; the RR for the occurrence of malignant cancer was 0.51 (95% CI. 0.23-1.16, =0.10) in FMF compared to Still's disease and 0.60 (95% CI. 0.29-1.28, =0.18) in FMF compared to Behçet's disease. At logistic regression, the risk of occurrence of malignant neoplasms in FMF patients was associated with the age at disease onset (β1 = 0.039, 95% CI. 0.001-0.071, =0.02), the age at the diagnosis (β1 = 0.048, 95% CI. 0.039-0.085, =0.006), the age at the enrolment (β1 = 0.05, 95% CI. 0.007-0.068, =0.01), the number of attacks per year (β1 = 0.011, 95% CI. 0.001- 0.019, =0.008), the use of biotechnological agents (β1 = 1.77, 95% CI. 0.43-3.19, =0.009), the use of anti-IL-1 agents (β1 = 2.089, 95% CI. 0.7-3.5, =0.002).

CONCLUSIONS: The risk for cancer is reduced in Caucasic FMF patients; however, when malignant neoplasms occur, this is more frequent in FMF cases suffering from a severe disease phenotype and presenting a colchicine-resistant disease.

Sjögren's disease (SjD) is a systemic autoimmune exocrinopathy with key features of dryness, pain, and fatigue. SjD can affect any organ system with a variety of presentations across individuals. This heterogeneity is one of the major barriers for developing effective disease modifying treatments. Defining core disease domains comprising both specific clinical features and incorporating the patient experience is a critical first step to define this complex disease. The OMERACT SjD Working Group held its first international collaborative hybrid meeting in 2023, applying the OMERACT 2.2 filter toward identification of core domains. We accomplished our first goal, a scoping literature review that was presented at the Special Interest Group held in May 2023. Building on the domains identified in the scoping review, we uniquely deployed multidisciplinary experts as part of our collaborative team to generate a provisional domain list that captures SjD heterogeneity.

Leptomeningeal disease (LMD) remains a rapidly lethal complication for late-stage melanoma patients. Here, we characterize the tumor microenvironment of LMD and patient-matched extra-cranial metastases using spatial transcriptomics in a small number of clinical specimens (nine tissues from two patients) with extensive in vitro and in vivo validation. The spatial landscape of melanoma LMD is characterized by a lack of immune infiltration and instead exhibits a higher level of stromal involvement. The tumor-stroma interactions at the leptomeninges activate tumor-promoting signaling, mediated through upregulation of SERPINA3. The meningeal stroma is required for melanoma cells to survive in the cerebrospinal fluid (CSF) and promotes MAPK inhibitor resistance. Knocking down SERPINA3 or inhibiting the downstream IGR1R/PI3K/AKT axis results in tumor cell death and re-sensitization to MAPK-targeting therapy. Our data provide a spatial atlas of melanoma LMD, identify the tumor-promoting role of meningeal stroma, and demonstrate a mechanism for overcoming microenvironment-mediated drug resistance in LMD.

Myocardial infarction (MI) is characterized by a significant loss of cardiomyocytes (CMs), and it is suggested that reactive oxygen species (ROS) are involved in cell cycle arrest, leading to impaired CM renewal. Thioredoxin-1 (Trx-1) scavenges ROS and may play a role in restoring CM renewal. However, the truncated form of Trx-1, Trx-80, can compromise its efficacy by exerting antagonistic effects. Therefore, a Trx-1 mimetic peptide called CB3 was tested as an alternative way to restore CMs. This study aimed to investigate the effects of Trx-1, Trx-80, and CB3 on mice with experimental MI and study the underlying mechanism of CB3 on CMs. Mouse cardiac parameters were quantified by echocardiography, and infarction size and fibrosis determined using Trichrome and Picro-Sirius Red staining. The study found that Trx-1 and CB3 improved mouse cardiac function, reduced the size of cardiac infarct and fibrosis, and decreased the expression of cardiac inflammatory markers. Furthermore, CB3 polarized macrophages into M2 phenotype, reduced apoptosis and oxidative stress after MI, and increased CM proliferation in cell culture and in vivo. CB3 effectively protected against myocardial infarction and could represent a new class of compounds for treating MI.

AIMS/INTRODUCTION: Coronavirus disease 2019 (COVID-19) vaccinations have been proven to be generally safe in healthy populations. However, the data on vaccine safety in patients with type 1 diabetes are scarce. This study aimed to evaluate the frequency and severity of short-term (<7-day) adverse vaccination events (AEs) and their risk factors among type 1 diabetes patients.

MATERIALS AND METHODS: This study analyzed data from the COVID-19 vaccination in Autoimmune Diseases (COVAD) survey database (May to December 2021; 110 collaborators, 94 countries), comparing <7-day COVID-19 vaccine AE among type 1 diabetes patients and healthy controls (HCs). Descriptive statistics; propensity score matching (1:4) using the variables age, sex and ethnicity; and multivariate analyses were carried out.

RESULTS: This study analyzed 5,480 completed survey responses. Of all responses, 5,408 were HCs, 72 were type 1 diabetes patients (43 females, 48.0% white European ancestry) and Pfizer was the most administered vaccine (39%). A total of 4,052 (73.9%) respondents had received two vaccine doses. Patients with type 1 diabetes had a comparable risk of injection site pain, minor and major vaccine AEs, as well as associated hospitalizations to HCs. However, type 1 diabetes patients had a higher risk of severe rashes (3% vs 0.4%, OR 8.0, 95% confidence interval 1.7-36), P = 0.007), although reassuringly, these were rare (n = 2 among type 1 diabetes patients).

CONCLUSIONS: COVID-19 vaccination was safe and well tolerated in patients with type 1 diabetes with similar AE profiles compared with HCs, although severe rashes were more common in type 1 diabetes patients.

Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management, and outcome are sparse.This international multicentre registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553 729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed, at 214 centres in 35 countries. In 78 centres 138 patients [0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (P < 0.0001)] were diagnosed with an oesophageal fistula. Peri-procedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0–60) days and 21 (15, 29.5; range: 2–63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0–42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8% and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) [odds ratio 7.463 (2.414, 23.072) P < 0.001].Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.