Search bioRxiv⌕ Search

Biology subjects

Souza, P.

Publications and source records attributed to Souza, P..

2 recordsLinked to original sources

Hoike: A Joint-Embedding Predictive Architecture for Transcriptome Data Generation with Diffusion Models

In biomarker discovery, access to sufficient quantities of condition-specific transcriptomic data is often limited by cohort size, privacy concerns, and domain shift between normal and condition populations. Generative modeling can augment scarce cohorts and probe distributional transitions. Furthermore, synthetic transcriptome generation can support differential expression analyses, machine learning, privacy-preserving data sharing, benchmarking, and hypothesis generation in translational bioinformatics workloads in fields such as oncology. Here, we present Hoike, a framework that combines a crossdomain Joint-Embedding Predictive Architecture (JEPA) with a latent diffusion model to generate condition-specific bulk transcriptomes from a normal reference context. In Hoike, normal tissue profiles provide continuous conditioning signals, while the model learns disease-linked shifts in latent space and reconstructs gene-level expression in log2(TPM+1) space. The implementation supports paired normal-condition training, tissuealigned conditioning, and constrained non-negative decoding for biologically valid outputs. We describe the architecture, objective design, and evaluation protocol used in this work across GTEx-derived normal references and multiple TCGA condition cohorts as a case study. This serves as the technical specification of the Hoike framework and its reproducible analysis workflow.

bioinformatics↗

Simultaneous adjustments of major mitochondrial pathways through redox regulation of dihydrolipoamide dehydrogenase (mtLPD1)

Thioredoxins (TRX) are pivotal for the redox regulation of enzyme activities to adjust metabolic fluxes towards environmental changes. Previous reports demonstrated TRX o1 and h2 impact on mitochondrial metabolism including photorespiration and the tricarboxylic acid (TCA) cycle. Here, we aimed to unravel potential specificities between regulation modes of both TRXs, especially under conditions with short-term changes in photorespiration. Therefore, short-term metabolite responses of single TRX mutants were analyzed after exposure to altered CO2/O2 ratios during darkness and illumination. This approach was complemented by comprehensive characterization of multiple Arabidopsis mutants lacking either one or both TRX in the wild-type Arabidopsis or the glycine decarboxylase (GDC) T-protein knock down line (gldt1). The results provided evidence for additive effects of combined TRX o1 and h2 deficiency to suppress growth, photosynthesis and mitochondrial metabolism. Quantification of pyrimidine nucleotides in conjunction with metabolite and 13C-labelling approaches revealed a rather uniform impact on mitochondrial dihydrolipoamide dehydrogenase (mtLPD1) dependent pathways. Biochemical analysis of recombinant mtLPD1 demonstrated its inhibition by NADH, pointing at an additional measure to fine-tune its in vivo activity. Collectively, we propose that TRX o1 and h2 contribute to the communication of altered subcellular redox-states through direct and indirect regulation of mtLPD1. This regulation module might represent a common intercept for simultaneous adjustments in the operation of photorespiration, the TCA-cycle and the degradation of branched chain amino acids. One-sentence summaryRedox regulation of mitochondrial dihydrolipoamide dehydrogenase (mtLPD1) simultaneously modulates photorespiration, the tricarboxylic acid (TCA)-cycle and branched chain amino acid (BCAA) degradation in response to rapid environmental changes.

plant biology↗