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While single-cell RNA sequencing has advanced our understanding of cell fate, identifying molecular hallmarks of potency—a cell’s ability to differentiate into other cell types—remains a challenge. Here we introduce CytoTRACE 2, an interpretable deep learning framework for predicting absolute developmental potential from single-cell RNA sequencing data. Across diverse platforms and tissues, CytoTRACE 2 outperformed previous methods in predicting developmental hierarchies, enabling detailed mapping of single-cell differentiation landscapes and expanding insights into cell potency. CytoTRACE 2 is an interpretable deep learning framework that leverages single-cell RNA sequencing data to predict absolute developmental potential across datasets.

BackgroundArginine metabolism in tumors is often shunted into the pathway producing pro-tumor and immune suppressive polyamines (PAs), while downmodulating the alternative nitric oxide (NO) synthesis pathway. Aiming to correct arginine metabolism in tumors, arginine deprivation therapy and inhibitors of PA synthesis have been developed. Despite some therapeutic advantages, these approaches have often yielded severe side effects, making it necessary to explore an alternative strategy. We previously reported that supplementing sepiapterin (SEP), the endogenous precursor of tetrahydrobiopterin (BH4, the essential NO synthase cofactor), could correct arginine metabolism in tumor cells and tumor-associated macrophages (TAMs) and induce their metabolic and phenotypic reprogramming. We saw that oral SEP treatment effectively suppressed the growth of HER2-positive mammary tumors in animals. SEP also has no reported dose-dependent toxicity in clinical trials for metabolic disorders. In the present study, we tested our hypothesis that a long-term administration of SEP to individuals susceptible to HER2-positive mammary tumor would protect them against tumor occurrence.MethodsWe administered SEP, in comparison to control DMSO, to MMTV-neu mice susceptible to HER2-positive mammary tumors for 8 months starting at their pre-pubertal stage. We monitored tumor onsets to determine the rate of tumor-free survival. After 8 months of treatment, we grouped animals into DMSO treatment with or without tumors and SEP treatment with or without tumors. We analyzed blood metabolites, PBMC, and bone marrow of DMSO vs. SEP treated animals.ResultsWe found that a long-term use of SEP in animals susceptible to HER2-positive mammary tumors effectively suppressed tumor occurrence. These SEP-treated animals had undergone reprogramming of the systemic metabolism and immunity, elevating total T cell counts in the circulation and bone marrow. Given that bone marrow-resident T cells are mostly memory T cells, it is plausible that chronic SEP treatment promoted memory T cell formation, leading to a potent tumor prevention.ConclusionsThese findings suggest the possible roles of the SEP/BH4/NO axis in promoting memory T cell formation and its potential therapeutic utility for preventing HER2-positive breast cancer.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40170-025-00384-4.

In vitro lymphocyte proliferation assays are essential for assessing immune responses and antiproliferative drug efficacy. Such assays rely on antigen presentation or mitogen stimulation, with performance determined by reagent concentration and incubation time. Although splenocytes are often used, peripheral blood mononuclear cells (PBMCs) offer more accessible and practical sampling. However, a streamlined protocol for porcine PBMCs proliferation with robust batch analysis has been lacking. We therefore developed a detailed workflow for inducing proliferation in cryopreserved porcine PBMCs using 5 μg/mL concanavalin A (ConA). The protocol covers cell isolation, cryopreservation, ConA stimulation, CD4+ T-cell staining, flow cytometry acquisition and gating on an Attune NxT instrument, and batch analysis with FCS ExpressTM 7.18. This approach yielded 78.9% viable cells, of which 33.8% were CD4+ lymphocytes. Moreover, 93.9% (n = 216) of cells proliferated, yielding up to nine cell generations. Batch analysis in FCS ExpressTM enhanced the accuracy and interpretation of proliferation metrics. This validated protocol provides a reliable framework for generating consistent proliferation data in porcine immunology studies. Key features • Optimized proliferation assay for cryopreserved porcine PBMCs: Ideal for immunological studies and biomedical research using swine models.• Precise acquisition and gating with Attune NxT flow cytometer: Ensures accurate identification and analysis of CD4+ T lymphocytes.• Robust data analysis using FCS ExpressTM 7.18 software: Facilitates reliable interpretation of lymphocyte proliferation and division indexes.• Efficient 4.5-day protocol: Enables timely and reproducible experiments in clinical and research settings involving porcine immune cells. Graphical overview Proliferation assay process from cryopreserved porcine peripheral blood mononuclear cells (PBMCs)