TRABOULSI, T. | bioRxiv Science

bioRxiv2026

Joint recording of past and present transcriptomes reconstructs single-cell trajectories

Tracing molecular cell state transitions through development, homeostasis and disease is still beyond reach at single-cell resolution. We present scReMeMber-Seq, a methylation-based cell-memory recorder connecting past transcriptional states with present transcriptome and DNA methylome in individual cells. scReMeMber-Seq leverages pulse induction of DCM-Polr2b (TimeMachine) and single-cell methylome-transcriptome (scMT) sequencing for endpoint readout. In mouse neural stem cells (NSCs) and pancreatic organoids, single-cell DCM methylation profiles (scDCMome) accurately discriminate cell types. Over time, scDCMome also record NSC quiescence-activation state changes across multiple cell divisions. In zebrafish embryos, scDCMome resolve individual transcriptional trajectories from progenitor to neuron. Together, scReMeMber-Seq enables real time reconstruction of cellular trajectories, connecting past and present molecular states in single cells, at genome scale, across experimental systems, in vitro and in vivo.

neuroscience↗

bioRxiv2026

Dysregulated dsRNA sensor signaling and viral infection during onset of pediatric autoimmune interferonopathy

Juvenile dermatomyositis (JDM) is characterized by a type I interferon (IFN-I) signature associated with disease activity. We previously identified a link between SARS-CoV-2 infection and the onset or relapse of JDM. Here, we show that newly diagnosed JDM patients display an overexpression of IFIH1 (encoding MDA5 protein) at baseline, coupled with an altered response to dsRNA stimulation at proteomic and transcriptomic levels, indicating abnormal activation of this antiviral sensing pathway. Single-cell transcriptomic and chromatin accessibility profiling of peripheral blood mononuclear cells (PBMCs) further revealed myeloid-specific enrichment of interferon-stimulated genes (ISGs) and preferential disruption of this pathway at disease onset, supporting a dysregulated IFN-I state in this cell type. We identified SARS-CoV-2 RNA in muscle biopsies of two Covid-19 pandemic-onset JDM patients, strongly implicating viral infection as a potential trigger of the dysregulated MDA5 immune response. To extend these observations beyond SARS-CoV-2, we screened two independent retrospective cohorts for antibodies against 27 common childhood infections. In our discovery cohort JDM patients showed significantly increased exposure to 4 RNA viruses in line with our immunological findings. Increased exposure to RSV B was confirmed in an independent replication cohort supporting a robust association with JDM pathophysiology. Together, these findings integrate systemic, single-cell, and tissue-level analyses implicating RNA viral infection and biased antiviral sensing in shaping IFN-I responses at JDM onset, providing mechanistic insight into environmentally triggered pathogenesis. One sentence summaryType I interferon dysregulation at juvenile dermatomyositis onset implicates altered dsRNA sensing and RNA viral exposure as potential disease triggers.

immunology↗