Biology subjects

Dombi, E.

Publications and source records attributed to Dombi, E..

4 recordsLinked to original sources

bioRxiv2026

Targeting NF-κB prevents Schwann cell reprogramming and plexiform neurofibroma initiation in mouse model of Nf1

Plexiform neurofibromas arise in approximately half of all individuals with Neurofibromatosis Type I (NF1). Genetic lesions apart from NF1 pathogenic variants are not present in NF1 mutant Schwann cells, suggesting that tumorigenesis may instead require cellular rewiring. To identify putatively re-wired tumor cells, we used multiplex imaging and flow cytometry to delineate markers that distinguish tumor Schwann cell from non-tumor Schwann cells. We identified tumor Schwann cells as CD44+;CD49f+ cells that show increased transcription of epithelial to mesenchymal plasticity (EMP)- associated genes. CD44+;CD49f+ expression was induced by treating Nf1-/- Schwann cells with stressors or by direct NF-{kappa}B pathway activation via IKK2; treated Schwann cells increased secretion of NF-{kappa}B targets and immune cell chemoattractants CCL2 and CCL3. In established tumors, MEK inhibition plus NF-{kappa}B blockade diminished tumor cell proliferation, tumor Schwann cells, immune cell populations, tumor cytokines and tumor number. Notably, transient single agent NF-{kappa}B pathway blockade was sufficient to significantly delay tumor formation in mice. Thus, Nf1 loss in Schwann cells is followed by NF-{kappa}B activation and cellular reprogramming that drives tumor initiation and targeting NF-{kappa}B activation can reduce NF1-deficient tumor formation.

cancer biology↗

bioRxiv2026

SoftHybrid: A Hybrid Imputation Algorithm Optimised for Single-Cell Proteomics Data

Missing values (MVs) remain a significant barrier to reliable proteomics analysis, particularly in single-cell proteomics, where small amounts of starting material and limits in detection drive Missing-Not-At-Random (MNAR) sparsity. Existing imputation methods typically target either Missing-At-Random (MAR) or MNAR mechanisms, resulting in a trade-off between replicate consistency and preservation of biological variation, and are largely designed for bulk data. Here, we introduce SoftHybrid, a data-driven imputation framework that jointly models missingness and protein abundance to estimate the probability of MNAR, enabling continuous weighting between MAR- and MNAR-oriented strategies. SoftHybrid requires no external priors (cell type labels, group annotations, predefined missingness assumptions, etc.), enabling fully unsupervised applications. Across ground truth benchmarks and real single-cell proteomics datasets, SoftHybrid outperforms existing methods at low input and matches or exceeds their performance at the mini-bulk level. By preserving proteomic structure and abundance accuracy, it enhances the recovery of biologically meaningful signals. SoftHybrid is implemented as an R package and is freely available on GitHub.

bioinformatics↗

bioRxiv2019

Loss of CHCHD2 and CHCHD10 activates OMA1 peptidase to disrupt mitochondrial cristae phenocopying patient mutations in vivo

Dominant mutations in the mitochondrial paralogs CHCHD2 (C2) and CHCHD10 (C10) were recently identified as causing Parkinsons disease and ALS/FTD/myopathy, respectively. Disruption of mitochondrial cristae has been observed in mutant C10 patient tissues and animal models, but the mechanism for this disruption remains controversial. Additionally, C10 patient mutant knock-in (KI) mice were recently reported to activate a mitochondrial integrated stress response (mt-ISR) and develop cardiomyopathy not seen in C10 knockout (KO) mice, calling into question whether mutant C10 pathogenesis is related to C2/C10 normal function or purely toxic gain of function. Here, using the first C2/10 double knockout (DKO) mice, we report that C10 pathogenesis and the normal function of C2/10 are intimately linked. Similar to patients with C10 mutations, we found that C2/10 DKO mice (but not either single KO mice) have disrupted mitochondrial cristae, due to cleavage of the mitochondrial shaping protein L-OPA1 by the stress-induced peptidase OMA1. OMA1 was found to be activated similarly in affected tissues of mutant C10 KI mice, demonstrating that L-OPA1 cleavage is a novel mechanism for cristae abnormalities due to both C10 mutation and C2/C10 loss, and that OMA1, a driver of neurodegeneration in other contexts, may be a therapeutic target. Finally, C2/10 DKO mice partially phenocopied mutant C10 KI mice with the development of cardiomyopathy and activation of the mt-ISR in affected tissues, tying mutant C10 pathogenesis to C2/C10 function.

cell biology↗

bioRxiv2019

Maternal circulating syncytiotrophoblast-derived extracellular vesicles contain biologically active 5’-tRNA halves

The placenta releases syncytiotrophoblast-derived extracellular vesicles (STB-EV) into the maternal circulation throughout gestation. STB-EV dependent signalling is believed to contribute to the widespread maternal adaptive physiological changes seen in pregnancy. Transfer RNA (tRNA) halves have been identified in vesicles released from other human and murine organ systems, which alter gene expression in target cells. Here, we characterise tRNA-half expression in STB-EV and demonstrate biological activity of a highly abundant tRNA-half. Short RNA from ex-vivo, dual-lobe placental perfusion STB-EV was sequenced, showing that most (>95%) comprised tRNA species. Whole placental tissue contained <50% tRNA species, suggesting selective packaging and export of tRNA into STB-EV. Most tRNA within STB-EV were 5-tRNA halves cleaved at 30-32 nucleotides. The pattern of tRNA expression differed depending on the size/origin of the STB-EV; this was confirmed by qPCR. Protein synthesis was suppressed in human fibroblasts when they were cultured with a 5-tRNA half identified from STB-EV sequencing. This study is the first to evaluate tRNA species in STB-EV. The presence of biologically active 5-tRNA halves, specific to a vesicular origin, suggests a novel mechanism for maternal-fetal signalling in normal pregnancy.

physiology↗