Biology subjects

Gopakumar, J.

Publications and source records attributed to Gopakumar, J..

4 recordsLinked to original sources

bioRxiv2026

FGF signaling induces disease-associated oligodendrocyte states and drives myelin pathology

Myelin integrity is essential for normal central nervous system (CNS) function and is disrupted in neuroinflammatory and neurodegenerative disorders, including multiple sclerosis and Alzheimer's disease. In these settings, myelin-forming oligodendrocytes adopt a conserved disease-associated transcriptional state, termed disease-associated oligodendrocytes (DAOs). How DAOs arise, the signals that drive their induction, and whether they actively contribute to pathology remain poorly understood. Here we show that FGF signaling instructs mature oligodendrocytes to enter disease-associated states that are sufficient to trigger myelin pathology. By screening disease-linked secreted factors, we identify FGF1 and FGF2 as potent inducers of a DAO-like state in purified oligodendrocyte cultures, characterized by transcriptional reprogramming and myelin-membrane shedding. In vivo, activating oligodendrocyte FGF signaling is sufficient to elicit DAO programs and myelin disruption, whereas inhibiting FGF signaling suppresses DAO induction in a mouse model of multiple sclerosis. Finally, analysis of post-mortem multiple sclerosis tissue reveals a concordant DAO-like state associated with increased engagement of the FGF/FGFR axis. Collectively, these studies define a regulated mechanism of DAO formation linked to myelin disruption and position mature oligodendrocytes as active contributors to myelin pathology in CNS disease.

neuroscience↗

bioRxiv2026

Choline Kinase Alpha Inhibition is a Mutation Agnostic Therapeutic Vulnerability in Clonal Hematopoiesis

Clonal Hematopoiesis (CH) affects the aging population and is associated with increased risk of hematological malignancy, cardiovascular disease, and all-cause mortality. Therapeutic options for CH remain limited. Using hematopoietic stem and progenitor cell (HSPC) color barcoding and mosaic mutagenesis in zebrafish, we identified perturbed choline metabolism and increased phosphatidylcholine (PC) biosynthesis via choline kinase alpha (CHKA) in asxl1-mutant HSPCs. Suppressing CHKA-dependent choline flux reduced ASXL1-driven clonal expansion. This effect was conserved in a murine DNMT3A and human TET2 model. Mechanistically, CHKA- dependent choline flux controls phosphatidylcholine production that supports platelet activating factor (PAF) production. Exogenous PAF overcomes the suppressive effect of CHKA inhibition in ASXL1 and TET2 models. We isolated primary, human HSPCs from the peripheral blood of patients with endogenous ASXL1 mutations and demonstrated that perturbing PAF signaling reduces their competitive potential in an ex vivo clonal competition assay. This CHKA/PAF axis is conserved in TET2-mutant HSPCs. Together, these findings identify a mutation agnostic metabolic dependency across the three most common CH genotypes and demonstrate that targeting the CHKA-dependent choline flux suppresses clonal expansion.

cancer biology↗

bioRxiv2026

Somatic mutations reveal the ontogeny of human microglia

Microglia are the resident hematopoietic cells of the central nervous system1. In mice, microglia seed the brain during embryogenesis and can be maintained throughout life with minimal input from adult hematopoiesis2-4. The origins of human microglia are less clear, but recent evidence suggests that marrow-derived cells may be able to supplement the human microglial pool in certain individuals5,6. Here, to investigate the ontogeny of human microglia, we develop a method that uses the collection of accumulated somatic mutations which uniquely labels each clone of cells to track the infiltration of marrow-derived cells into the human brain. Applying this method to 20 aged individuals, we find evidence of an influx of marrow-derived cells into the brain in all examined individuals. Single cell analysis, including single cell lineage tracing using mitochondrial DNA variants, demonstrates that these infiltrating cells are nearly identical to microglia and can comprise a large fraction of the microglial pool. Analysis of large-scale sequencing cohorts demonstrates a protective association between most types of clonal hematopoiesis and Alzheimers disease. In sum, this work uncovers a widespread influx of myeloid cells into the healthy human brain which serves to reinforce the pool of human microglia and becomes common with aging.

immunology↗

bioRxiv2021

Clonal hematopoiesis is driven by aberrant activation of TCL1A

A diverse set of driver genes, such as regulators of DNA methylation, RNA splicing, and chromatin remodeling, have been associated with pre-malignant clonal expansion of hematopoietic stem cells (HSCs). The factors mediating expansion of these mutant clones remain largely unknown, partially due to a paucity of large cohorts with longitudinal blood sampling. To circumvent this limitation, we developed and validated a method to infer clonal expansion rate from single timepoint data called PACER (passenger-approximated clonal expansion rate). Applying PACER to 5,071 persons with clonal hematopoiesis accurately recapitulated the known fitness effects due to different driver mutations. A genome-wide association study of PACER revealed that a common inherited polymorphism in the TCL1A promoter was associated with slower clonal expansion. Those carrying two copies of this protective allele had up to 80% reduced odds of having driver mutations in TET2, ASXL1, SF3B1, SRSF2, and JAK2, but not DNMT3A. TCL1A was not expressed in normal or DNMT3A-mutated HSCs, but the introduction of mutations in TET2 or ASXL1 by CRISPR editing led to aberrant expression of TCL1A and expansion of HSCs in vitro. These effects were abrogated in HSCs from donors carrying the protective TCL1A allele. Our results indicate that the fitness advantage of multiple common driver genes in clonal hematopoiesis is mediated through TCL1A activation. PACER is an approach that can be widely applied to uncover genetic and environmental determinants of pre-malignant clonal expansion in blood and other tissues.

genetics↗