BRD3OS Dysregulation in Antiphospholipid Syndrome: Integrative Network and RNA Structural Analysis of m6A-Related Candidate Regions

Abstract

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by thrombotic and inflammatory manifestations whose molecular regulatory mechanisms remain incompletely understood. Long non-coding RNAs (lncRNAs) and N6-methyladenosine (m6A)-related regulation are increasingly recognized as components of immune gene regulation, but their involvement in APS remains poorly characterized. This study investigated BRD3OS (LINC00094) expression in APS and explored its molecular and predicted structural context in relation to m6A-associated regulation. An exploratory case–control study was conducted using an initial lncRNA PCR-array discovery cohort followed by targeted RT-qPCR validation in an independent cohort. Candidate prioritization incorporated multiple expression and technical features and was evaluated through sensitivity analyses. BRD3OS expression, selected m6A regulators (METTL3, METTL14, WTAP, and FTO), inflammatory mediators, and global m6A abundance in total peripheral blood mononuclear cell (PBMC) RNA were evaluated. Bioinformatic network analysis was used to contextualize BRD3OS within APS- and m6A-related molecular systems. RNAfold and RNAplfold were used to characterize the predicted structural context and accessibility of DRACH consensus motifs, with additional analyses evaluating fragment-boundary and composite-score robustness. BRD3OS was significantly downregulated in PBMCs from patients with APS in the independent validation cohort. METTL3, METTL14, and WTAP expression was also reduced, whereas global m6A levels in total PBMC RNA were increased. These observations indicate concurrent alterations in BRD3OS expression and the broader m6A-related molecular environment but do not establish transcript-specific methylation of BRD3OS. Bioinformatic network analysis placed BRD3OS within predicted RNA-centered regulatory relationships relevant to APS. DRACH motifs exhibited heterogeneous predicted structural accessibility, with unpaired structural environments showing greater RNAplfold-derived accessibility than paired regions. Quantitative accessibility estimates were highly concordant across overlapping transcript fragments, although sensitivity analyses indicated that the identity of individual highest-ranked candidates depended on the weighting scheme. BRD3OS downregulation represents a reproducible molecular finding in APS. Concurrent alterations in global m6A abundance and selected m6A regulators suggest broader epitranscriptomic dysregulation; however, these measurements cannot establish m6A modification of BRD3OS or a causal relationship between these observations. Structural and network analyses therefore provide a hypothesis-generating framework for prioritizing candidate regions and interactions for future transcript-specific methylation mapping and functional validation.