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Directed evolution is a process of mutation and artificial selection to breed biomolecules with new or improved activity. Directed evolution platforms are primarily prokaryotic or yeast-based, and stable mammalian systems have been challenging to establish and apply. To this end, we develop PROTein Evolution Using Selection (PROTEUS), a platform that uses chimeric virus-like vesicles to enable extended mammalian directed evolution campaigns without loss of system integrity. This platform is stable and can generate sufficient diversity for directed evolution in mammalian systems. Using PROTEUS, we alter the doxycycline responsiveness of tetracycline-controlled transactivators, generating a more sensitive TetON-4G tool for gene regulation with mammalian-specific adaptations. PROTEUS is also compatible with intracellular nanobody evolution, and we use it to evolve a DNA damage-responsive anti-p53 nanobody. Overall, PROTEUS is an efficient and stable platform to direct evolution of biomolecules within mammalian cells. Subject terms: Synthetic biology, Synthetic biology, Molecular evolution, Next-generation sequencing

The ten‐eleven translocation family of enzymes (TET1/2/3) promotes DNA demethylation and is essential for hematopoiesis. While the roles of TET1 and TET2 are well‐studied in hematopoiesis, the requirement of TET3 in embryonic and adult hematopoiesis is less investigated. In this study, by characterizing embryonic and adult hematopoiesis in Tie2 +/cre ; Tet3 f/f mice, we have established a requirement for TET3 in regulating hematopoietic stem cells (HSCs; CD150 + CD48 – ). We found that loss of TET3 in the fetal liver and adult bone marrow causes a reduction in the percent of long‐term HSCs (LT‐HSCs; CD150 + CD48 – CD34 – ). This was accompanied by reduced colony forming capacity of TET3‐deficient HSCs in vitro and reduced contribution of HSCs after a competitive bone marrow transplantation in vivo. TET3 deficiency increased DNA methylation at several cell cycle regulator genes leading to their down regulation. This is consistent with, and likely underpins, the reduced number of quiescent HSCs in TET3‐deficient bone marrow. These findings uncover a new role for TET3 in HSC homeostasis during embryonic and adult hematopoiesis.

Tumor-associated macrophages (TAMs) are key promoters of inflammatory breast cancer (IBC), the most aggressive form of breast cancer. The receptor tyrosine kinase AXL is highly expressed in various cancer types, including IBC, but its role in TAMs remains unexplored. We examined the effects of AXL inhibitor TP-0903 on tumor growth and tumor microenvironment (TME) component M2 macrophages (CD206 + ) in IBC and triple-negative breast cancer mouse models using flow cytometry and immunohistochemical staining. Additionally, we knocked out AXL expression in human THP-1 monocytes and evaluated the effect of AXL signaling on immunosuppressive M2 macrophage polarization and IBC cell growth and migration. We then investigated the underlying mechanisms through RNA sequencing analysis. Last, we performed CIBERSORT deconvolution to analyze the association between AXL expression and tumor-infiltrating immune cell types in tumor samples from the Inflammatory Breast Cancer International Consortium. We found that inhibiting the AXL pathway significantly reduced IBC tumor growth and decreased CD206 + macrophage populations within tumors. Mechanistically, our in vitro data showed that AXL promoted M2 macrophage polarization and enhanced the secretion of immunosuppressive chemokines, including CCL20, CCL26, and epiregulin, via the transcription factor STAT6 and thereby accelerated IBC cell growth and migration. RNA sequencing analysis further indicated that AXL signaling in immunosuppressive M2 macrophages regulated the expression of molecules and cytokines, contributing to an immunosuppressive TME in IBC. Moreover, high AXL expression was correlated with larger populations of immunosuppressive immune cells but smaller populations of immunoactive immune cells in tissues from patients with IBC. AXL signaling promotes IBC growth by inducing M2 macrophage polarization and driving the secretion of immunosuppressive molecules and cytokines via STAT6 signaling, thereby contributing to an immunosuppressive TME. Collectively, these findings highlight the potential of targeting AXL signaling as a novel therapeutic approach for IBC that warrants further investigation in clinical trials. The online version contains supplementary material available at 10.1186/s13058-025-02015-8.

Mesenchymal stem cells (MSCs) are promising for cell-based therapies targeting a wide range of diseases. However, challenges in translating MSC-based therapies to clinical applications necessitate standardized protocols following Good Manufacturing Practices (GMP) guidelines. This study aimed at developing GMP-complained protocols for FPMSCs isolation and manipulation, necessary for translational research, by (1) optimize culture of MSCs derived from an infrapatellar fat pad (FPMSC) condition through animal-free media comparison and (2) establish feasibility of MSC isolation, manufacturing and storage under GMP-compliance (GMP-FPMSC). FPMSCs from three different patients were isolated following established protocols and the efficacy of two animal component-free media formulations in the culturing media were evaluated. The impact of different media formulations on cell proliferation, purity, and potency of MSCs was evaluated through doubling time, colony forming unit assay, and percentage of MSCs, respectively. Furthermore, the isolation and expansion of GMP-FPMSCs from four additional donors were optimized and characterized at each stage according to GMP requirements. Viability and sterility were checked using Trypan Blue and Bact/Alert, respectively, while purity and identity were confirmed using Endotoxin, Mycoplasma assays, and Flow Cytometry. The study also included stability assessments post-thaw and viability assessment to determine the shelf-life of the final GMP-FPMSC product. Statistical analyses were conducted using one-way ANOVA with Tukey’s Multiple Comparisons. The study demonstrated that FPMSCs exhibited enhanced proliferation rates when cultured in MSC-Brew GMP Medium compared to standard MSC media. Cells cultured in this media showed lower doubling times across passages, indicating increased proliferation. Additionally, higher colony formation in FPMSCs cultured in MSC-Brew GMP Medium were observed, supporting enhanced potency. Data from our GMP validation, including cells from 4 different donors, showed post-thaw GMP-FPMSC maintained stem cell marker expression and all the specifications required for product release, including > 95% viability (> 70% is required) and sterility, even after extended storage (up to 180 days), demonstrating the reproducibility and potential of GMP-FPMSCs for clinical use as well as the robustness of the isolation and storage protocols. The study underscores the feasibility of FPMSCs for clinical uses under GMP conditions and emphasizes the importance of optimized culture protocols to improve cell proliferation and potency in MSC-based therapies. The online version contains supplementary material available at 10.1186/s12860-025-00539-7.

Transition from the manual processes that are performed during the initial research and development (R&D) stage to automated processes for later and commercial stage cell therapy manufacturing can be challenging. It often requires significant effort, time, and costs – which hinders the therapy’s access to the clinic. To ease this transition, we have developed a novel and flexible manufacturing platform, Bioreactor with Expandable Culture Area (BECA), that aims to support both R&D and manufacturing to accelerate cell therapies from bench to bedside. This report introduces two models in this manufacturing platform: BECA-S for manual small-scale operation at R&D phase and BECA-Auto for functionally closed and automated scaled-out operation at manufacturing phase. We employed these two models to streamline transition of the T cell culture process from manual to automated and reported insignificant differences in the culture outcome between the two. Our work represents the first detailed development and demonstration of a standalone cell manufacturing platform that facilitates a seamless transition between manual and automated processing for autologous T cell therapy manufacturing.

Metabolic reprogramming of amino acids represents a vulnerability in cancer cells, yet the mechanisms underlying serine metabolism in acute myeloid leukemia (AML) and leukemia stem/initiating cells (LSCs/LICs) remain unclear. Here, we identify RNA N 6 -methyladenosine (m 6 A) modification as a key regulator of serine biosynthesis in AML. Using a CRISPR/Cas9 screen, we find that depletion of m 6 A regulators IGF2BP3 or METTL14 sensitizes AML cells to serine and glycine (SG) deprivation. IGF2BP3 recognizies m 6 A on mRNAs of key serine synthesis pathway (SSP) genes (e.g., ATF4 , PHGDH , PSAT1 ), stabilizing these transcripts and sustaining serine production to meet the high metabolic demand of AML cells and LSCs/LICs. IGF2BP3 silencing combined with dietary SG restriction potently inhibits AML in vitro and in vivo, while its deletion spares normal hematopoiesis. Our findings reveal the critical role of m 6 A modification in the serine metabolic vulnerability of AML and highlight the IGF2BP3/m 6 A/SSP axis as a promising therapeutic target. Subject terms: Acute myeloid leukaemia, Cancer metabolism

Mounting evidence indicates that exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs-exosomes) combine the advantages of hucMSC pluripotency with their nanoscale dimensions, enhancing their clinical potential through prolonged circulation half-life. Despite these promising characteristics, research on their immunological toxicity remains insufficient. This study focuses on the impact of hucMSC-exosomes on the general toxicity and immunopathological indicators. When mice received tail vein injections of 6 × 10 10 hucMSC-exosomes particles, we observed no significant changes in body weight, feed intake, blood composition, organ indices, or histopathological findings throughout the 14 days observation period. Similarly, blood levels of immunoglobulins, cytokines, and lymphocyte subpopulations remained stable. The hucMSC-exosomes produced no detectable negative effects on immune organs including the thymus, spleen, and bone marrow. These findings indicate that intravenous administration of 6 × 10 10 particles of hucMSC-exosomes appears relatively safe at the murine level. This assessment of safety and immunological impact following intravenous hucMSC-exosomes infusion offers experimental support for potential clinical applications and future analyses in this field.

Microglia perform key homeostatic functions to protect the central nervous system (CNS). However, in many brain disorders their protective functions are abrogated, contributing to disease progression. Therefore, studies of microglial function are critical to developing treatments for brain disorders. Different in vitro microglia models have been established, including primary human and rodent cells, induced pluripotent stem cell (iPSC)-derived models, and immortalised cell lines. However, a direct comparative analysis of the phenotypic and functional characteristics of these models has not been undertaken. Accurate modelling of human microglia in vitro is critical for ensuring the translatability of results from the bench to the brain. Therefore, our study aimed to characterise and compare commonly utilised in vitro microglia models. We assessed four established microglia models: primary human microglia, human iPSC-derived microglia, the human microglial clone 3 (HMC3) cell line, and primary mouse microglia, with primary human brain pericytes acting as a negative control. Primary human microglia, iPSC-derived microglia, and mouse microglia stained positive for myeloid-cell markers (Iba1, CD45 and PU.1), while HMC3 cells only stained positive for mural-cell markers (PDGFRβ and NG2). Distinct secretomes were observed in all cell models in response to inflammatory treatment, with iPSC-derived microglia showing the most significant inflammatory secretions. Notably, nitric oxide was only secreted by mouse microglia. Although all cell types exhibited phagocytic capacity, primary human microglia and iPSC-derived microglia displayed significantly higher levels of phagocytosis. Overall, comparative analysis revealed notable differences between human microglia, iPSC-derived microglia, HMC3 cells and mouse microglia. Such differences should be considered when using these models to study human brain diseases. Experimental findings obtained from mouse models or cell lines should ultimately be cross validated to ensure the translatability of results to the human condition.

Cancer stem cells (CSCs) play crucial roles in tumor metastasis, therapy resistance, and immune evasion. Identifying and understanding the factors that regulate the stemness of tumor cells presents promising opportunities for developing effective therapeutic strategies. In this study on oral squamous cell carcinoma (OSCC), we confirmed the key role of KLF7 in maintaining the stemness of OSCC. Using chromatin immunoprecipitation sequencing and dual-luciferase assays, we identified ITGA2, a membrane receptor, as a key downstream gene regulated by KLF7 in the maintenance of stemness. Tumor sphere formation assays, flow cytometry analyses, and in vivo limiting dilution tumorigenicity evaluations demonstrated that knocking down ITGA2 significantly impaired stemness. Upon binding to its extracellular matrix (ECM) ligand, type I collagen, ITGA2 activates stemness-associated signaling pathways, including PI3K-AKT, MAPK, and Hippo. TC-I 15, a small-molecule inhibitor of the ITGA2-collagen interaction, significantly sensitizes oral squamous cell carcinoma (OSCC) to cisplatin in xenograft models. In summary, we reveal that the KLF7/ITGA2 axis is a crucial modulator of stemness in OSCC. Our findings suggest that ITGA2 is a promising therapeutic target, offering a novel anti-CSC strategy. Subject terms: Cancer stem cells, Cancer therapeutic resistance

In Alzheimer’s disease, amyloid beta (Aβ) and tau pathology are thought to drive synapse loss. However, there is limited information on how endogenous levels of tau, Aβ and other biomarkers relate to patient characteristics, or how manipulating physiological levels of Aβ impacts synapses in living adult human brain. Using live human brain slice cultures, we report that Aβ 1-40 and tau release levels vary with donor age and brain region, respectively. Release of other biomarkers such as KLK-6, NCAM-1, and Neurogranin vary between brain region, while TDP-43 and NCAM-1 release is impacted by sex. Pharmacological manipulation of Aβ in either direction results in a loss of synaptophysin puncta, with increased physiological Aβ triggering potentially compensatory synaptic transcript changes. In contrast, treatment with Aβ-containing Alzheimer’s disease brain extract results in post-synaptic Aβ uptake and pre-synaptic puncta loss without affecting synaptic transcripts. These data reveal distinct effects of physiological and pathological Aβ on synapses in human brain tissue. Subject terms: Alzheimer's disease, Alzheimer's disease

The interplay between 3D genomic structure and transposable elements (TE) in regulating cell state-specific gene expression program is largely unknown. Here, we explore the utilization of TE-derived enhancers in naïve and expanded pluripotent states by integrative analysis of genome-wide Hi-C-defined enhancer interactions, H3K27ac HiChIP profiling and CRISPR-guided TE proteomics landscape. We find that short interspersed nuclear elements (SINEs) are the more involved TEs in the active chromatin and 3D genome architecture. In particular, mammalian-wide interspersed repeat (MIR), a SINE family member, is highly associated with naïve-specific genomic interactions compared to the expanded state. Primarily, in the naïve pluripotent state, MIR enhancer is co-opted by ESRRB for naïve-specific gene expression program. This ESRRB and MIR enhancer interaction is crucial for the formation of loops that build a network of enhancers and super-enhancers regulating pluripotency genes. We demonstrate that loss of a ESRRB-bound MIR enhancer impairs self-renewal. We also find that MIR is co-bound by structural protein complex, ESRRB-YY1, in the naïve pluripotent state. Altogether, our study highlights the topological regulation of ESRRB on MIR in the naïve potency state. The online version contains supplementary material available at 10.1186/s13059-025-03577-8.

Metastasis is one of the leading causes of cancer-related death worldwide. Fascin, a protein that bundles actin filaments to produce protrusions in cancer cells, plays a significant role in the enhancement of cell migration. This protein has been shown that the overexpression of this protein is related to the appearance of different types of cancer, such as colorectal cancer. In this study, we conducted in silico screening of the Enamine library, a compound library with a broad chemical space. Using a ligand-based virtual screening approach based on the pharmacophore model of G2, we identified the predicted inhibitors. First, these compounds were validated by physicochemical analysis. Differential scanning calorimetry (DSF) was used to study the binding between the predicted compounds and fascin protein, followed by an F-actin bundling assay to determine which compounds inhibited the bundling function of fascin. Z1362873773, which exhibited binding to fascin and inhibited F-actin bundling, was further tested in cell cultures to assess its effects on cancer cell viability and migration as well as in organoid models to evaluate potential cytotoxicity. Finally, we established a protocol that can be applied to discover anti-fascin agents from diverse compound libraries. A new molecule has been identified with considerable fascin inhibitory and migration-arresting capacity, which may lead to the development of new therapies to treat cancer. The online version contains supplementary material available at 10.1038/s41598-025-96457-x. Subject terms: Biochemistry, Biophysics, Cancer, Drug discovery, Molecular biology, Virtual drug screening