Biology subjects

Toma, M.

Publications and source records attributed to Toma, M..

9 recordsLinked to original sources

bioRxiv2026

SPARQ-MI leverages end-to-end spatial single-cell analysis of the tumor microenvironment

Detailed spatial analysis of the tumor micro-environment (TME) through multiplexed fluorescence imaging requires quantitative image-processing and data-analysis methods. While data-preprocessing down to segmentation of individual cells is captured by available methods, statistical analysis of single-cell features is compromised by the uneven noise distribution especially in complex tissues such as the TME, as well as by labor-intensive manual cell-type annotation and region segmentation. Here, we present SPARQ-MI (Spatial Phenotyping, Architecture Reconstruction and Quantification from Multiplexed Imaging) for streamlined spatial single-cell analysis, along with a tissue microarray PhenoCycler data-set with 37 fluorescent channels from melanoma patients under immunotherapy. We demonstrate that SPARQ-MI enables robust reconstruction of the cellular and spatial composition in this and other tissue types. Our analysis reveals associations of the cell-state and spatial location of CD8 T cells with response to immunotherapy. Overall, SPARQ-MI allows for quantitative analysis of complex fluorescence histology samples under minimal user input, and accounting for spatially uneven coverage of antibody signals, setting the stage for quantitative analysis of clinical samples.

bioinformatics↗

bioRxiv2025

Human chronic inflammation is orchestrated by spatially restricted inflammation-activated Dendritic cells

Dendritic cells (DCs) form coordinated networks that orchestrate inflammatory responses across tissues. Upon activation, conventional dendritic cells (DCs) undergo changes in their transcriptome, phenotype, and function, depending on the tissue microenvironment. The role of DC activation during human chronic inflammation has yet to be explored. To address this, we aimed to investigate activated DCs across a range of chronically inflamed human tissues, with a focus on cervical lymph nodes (LNs). We performed scRNAseq and flow cytometry on healthy, acutely, chronically inflamed, and cancer-associated human cervical (LNs) and identified a novel inflammation-associated DC (iaDC) cell state, found only within chronically inflamed LNs. iaDCs were defined by a unique cytokine expression profile (CXCL9, CXCL10, IL1B) and could be phenotypically distinguished from other activated DCs by their elevated expression of CD1C, CD206, CD319, and CD274. Functionally, we found that IFN{gamma} signaling induces DC2s to enter the iaDC cell state and that this process can be abrogated by inhibition of JAK-STAT signaling. Using spatial transcriptomics, we observed LN iaDC residing within a specific chronic inflammatory niche, which was enriched for inflammatory monocytes, NK cells, and effector memory CD4+ and CD8+ T cells. Extrapolating our findings to other chronic inflammation-associated diseases, we similarly observed the emergence of iaDCs within the intestines of treatment-resistant Crohns Disease patients, synovial membranes and lymph nodes of rheumatoid arthritis patients and lungs of sarcoidosis patients. Similarly to the lymph node, iaDCs were found to reside in conserved chronic inflammation-associated spatial niches within the small intestine of affected individuals and displayed equivalent transcriptional characteristics and surrounding cellular neighborhoods. Collectively, these data highlight a previously unexplored role of iaDCs in human chronic inflammatory diseases and propose a conserved spatially restricted iaDC-populated chronic inflammatory niche associated with resistance to therapy. These findings highlight novel avenues to shape inflammatory trajectories by targeting iaDCs and their spatial niches, for example, by inhibiting JAK-STAT signaling.

immunology↗

bioRxiv2025

NKG7 is a stable marker of cytotoxicity across immune contexts and within the tumor microenvironment

Cytotoxicity is a cornerstone of immune defense, critical for combating tumors and infections. This process relies on the coordinated action of granzymes and pore-forming proteins, with Granzyme B (GZMB) and Perforin (PRF1) being key markers and the most widely studied molecules pertaining to cytotoxicity. However, other human granzymes and cytotoxic components remain underexplored, despite growing evidence of their distinct, context-dependent roles. Natural Killer Cell Granule Protein 7 (NKG7) has recently emerged as a crucial cytotoxicity regulator, yet its expression patterns and function are poorly understood. Using large publicly available single-cell RNA sequencing atlases, we performed a comprehensive profiling of cytotoxicity across immune subsets and tissues. Our analysis highlights NKG7 expression as a strong marker of cytotoxicity, exhibiting a strong correlation with overall cytotoxic activity (r = 0.97) and surpassing traditional markers such as Granzyme B and Perforin in reliability. Furthermore, NKG7 expression is notably consistent across diverse immune subsets and tissues, reinforcing its versatility and robustness as a cytotoxicity marker. These findings position NKG7 as an invaluable tool for evaluating immune responses and a reliable indicator of cytotoxic functionality across biological and clinical contexts.

immunology↗

bioRxiv2024

The CCR4/CCL17 axis drives intestinal acute Graft versus Host disease after allogeneic bone marrow transplantation

Acute-Graft-versus-Host disease (aGvHD) is a life-threatening complication after allogeneic stem-cell-transplantation. It is mediated by alloreactive T cells whose trafficking to aGvHD target organs is orchestrated by chemokines. We here asked whether CCL17 and its corresponding receptor CCR4 are involved in aGvHD development and severity. We applied an experimental mouse model of aGvHD in CCR4/CCL17 knockout mice and analyzed gut biopsies of GvHD patients. We show that the absence of CCR4 in transplanted T cells induced significantly less severe aGvHD. This was accompanied by reduced expression of Gata3. Mechanistically, only CD4+, but not CD8+CCR4-/- T cells protected from aGvHD. We next identified dendritic cells in the small intestine to produce CCL17, which selectively recruited CD4+ T cells. IL-4 production by intestinal CD4+ T cells promoted proliferation of CD8+ T cells. In line, we detected an upregulation of CCL17 and Gata3 in human aGvHD samples. Our results indicate that local CCL17 production in aGvHD target organs recruits T cells, reinforcing local tissue damage and immune cell recruitment. We identified the JAK1/2-inhibitor ruxolitinib to dampen CCL17-expression, thereby reducing GvHD severity. We here dissect a to date unknown role of the CCL17-CCR4 axis in aGvHD, which might help to develop novel therapeutic strategies.

immunology↗

bioRxiv2023

Humans progressively feel agency over events triggered before their actions

Artificial Intelligence (AI) has become increasingly efficient in anticipating our behavior. Will this impact, in the near future, how much we feel control over events generated with AI-assistance? This would in turn influence our decisions, actions, mental health and sense of responsibility. In everyday life, our sense of agency over events occurring at various delays after our actions has adapted to accommodate these delays. Here, we investigate whether our sense of agency can also adapt to an unusual situation where a consequence precedes an action. We used an online game in which players aimed to beat the computer at finding and clicking on a target to trigger an animation, while, in fact, an algorithm triggered the animation before the players click. The animation was not randomly controlled by the algorithm, but rather based on the history of the players past movements and on the beginning of their current movement. We used correlational, machine learning decoding, and modelling approaches to capture how players compute their reported sense of agency over the animation. We found evidence that, in less than an hour, players implicitly learned that the timing of the animation was related to their own actions, and adapted their sense of agency accordingly. Such findings may help us to anticipate how humans will integrate AI-assistance to guide their behavior.

neuroscience↗

bioRxiv2023

IL-1R signaling drives enteric glia-macrophage interaction in colorectal cancer progression

Enteric glial cells (EGCs) have been implicated in colorectal cancer (CRC) pathogenesis. However, their precise mechanisms of interaction with the CRC immune cell compartment and pro-tumorigenic role remain unclear. This study aimed to investigate the immunomodulatory effects of EGCs on tumor-associated macrophages (TAMs) and their involvement in CRC progression. Using EGC depletion and supplementation models, we assessed the impact of EGCs on the immunomodulation of orthotopic murine CRC. Furthermore, by making use of Bulk RNA-sequencing of CRC EGCs and single-cell sequencing of the tumor microenvironment, we identified the factors involved in the EGC-TAM crosstalk. Findings demonstrate that EGCs acquire a reactive and immunomodulatory phenotype in both murine CRC models and patients, influencing TAM differentiation. Mechanistically, secretion of IL-1 by tumor-infiltrating monocytes and macrophages triggers the phenotypic and functional switch of CRC EGCs via IL-1R. Consequently, tumor EGCs secrete IL-6, promoting the differentiation of monocytes into pro-tumorigenic SPP1+ TAMs. Importantly, the reactive tumor EGCs phenotype correlates with worse disease outcomes in preclinical models and CRC patients. Here we uncover a previously unexplored neuroimmune interaction between EGCs and TAMs within the colorectal tumor microenvironment, informing potential therapeutic strategies and enhancing our understanding of CRC progression. eTOC SummaryOur study unveils a novel neuroimmune interaction between enteric glia and TAMs in colon carcinoma. Monocyte/Macrophage-derived IL-1 activates enteric glia, leading to the differentiation of pro-tumorigenic SPP1+ TAMs via glial-derived IL-6. Blocking glial IL-1R-signaling reduces colonic tumor lesions, highlighting IL-1R as a potential therapeutic target.

cancer biology↗

bioRxiv2022

Human skin specific long noncoding RNA HOXC13-AS regulates epidermal differentiation by interfering with Golgi-ER retrograde transport

After a skin injury, keratinocytes switch from a state of homeostasis to one of regeneration leading to the reconstruction of the epidermal barrier. The regulatory mechanism of gene expression underpinning this key switch during human skin wound healing is enigmatic. Long noncoding RNAs (lncRNAs) constitute a new horizon in the understanding of the regulatory programmes encoded in the mammalian genome. By comparing the transcriptome of an acute human wound and skin from the same donor as well as keratinocytes isolated from these paired tissue samples, we generated a list of lncRNAs showing changed expression in keratinocytes during wound repair. Our study focused on HOXC13-AS, a recently evolved human lncRNA specifically expressed in epidermal keratinocytes, and we found that its expression was temporally downregulated during wound healing. In line with its enrichment in suprabasal keratinocytes, HOXC13-AS was found to be increasingly expressed during keratinocyte differentiation, but its expression was reduced by EGFR signalling. After HOXC13-AS knockdown or overexpression in human primary keratinocytes undergoing differentiation induced by cell suspension or calcium treatment and in organotypic epidermis, we found that keratinocyte differentiation was promoted, while the cell inflammatory response was suppressed. Moreover, RNA pull-down assays followed by mass spectrometry and RNA immunoprecipitation analysis revealed that mechanistically HOXC13-AS sequestered the coat complex subunit alpha (COPA) protein and interfered with Golgi-to-endoplasmic reticulum (ER) molecular transport, resulting in ER stress and enhanced keratinocyte differentiation. In summary, we identified HOXC13-AS as a crucial regulator of human epidermal differentiation.

molecular biology↗

bioRxiv2021

Single-cell analysis reveals MHCII expressing keratinocytes in pressure ulcers with worse healing outcomes

Pressure ulcer (PU) is a chronic wound often seen in spinal cord injury patients and other bed-bound individuals, particularly in the elderly population. Despite its association with high mortality, the pathophysiology of PU remains poorly understood. Here, we compared single-cell transcriptomic profiles of human epidermal cells from PU wound edges with those from uninjured skin and acute wounds (AWs) in healthy donors. We identified significant shifts in the cell composition and gene expression patterns in PU. In particular, we found that major histocompatibility complex class II (MHCII) expressing keratinocytes were enriched in patients with worse healing outcomes. Furthermore, we showed that the IFN{gamma} in PU-derived wound fluid could induce MHCII expression in keratinocytes and that these wound fluid-treated keratinocytes inhibited autologous T cell activation. In line with this observation, we found that T cells from PUs enriched with MHCII+ keratinocytes produced fewer inflammatory cytokines. Overall, our study provides a high-resolution molecular map of human PU compared to AW and intact skin, providing new insights into PU pathology and the future development of tailored wound therapy.

genomics↗

bioRxiv2021

GLS-driven glutamine catabolism contributes to prostate cancer radiosensitivity by regulating the redox state, stemness and ATG5-mediated autophagy

Radiotherapy is one of the curative treatment options for localized prostate cancer (PCa). The curative potential of radiotherapy is mediated by irradiation-induced oxidative stress and DNA damage in tumor cells. However, PCa radiocurability can be impeded by tumor resistance mechanisms and normal tissue toxicity. Metabolic reprogramming is one of the major hallmarks of tumor progression and therapy resistance. Here, we found that radioresistant PCa cells and prostate cancer stem cells (CSCs) have a high glutamine demand. Glutaminase (GLS)-driven catabolism of glutamine serves not only for energy production but also for the maintenance of the redox state. Consequently, glutamine depletion or inhibition of critical regulators of glutamine utilization, such as glutaminase (GLS) and the transcription factor MYC results in PCa radiosensitization. On the contrary, we found that a combination of glutamine metabolism inhibitors with irradiation does not cause toxic effects on nonmalignant prostate cells. Glutamine catabolism contributes to the maintenance of CSCs through regulation of the alpha-ketoglutarate (-KG)-dependent chromatin-modifying dioxygenase. The lack of glutamine results in the inhibition of CSCs with a high aldehyde dehydrogenase (ALDH) activity, decreases the frequency of the CSC populations in vivo and reduces tumor formation in xenograft mouse models. Moreover, this study shows that activation of the ATG5-mediated autophagy in response to a lack of glutamine is a tumor survival strategy to withstand radiation-mediated cell damage. In combination with autophagy inhibition, the blockade of glutamine metabolism might be a promising strategy for PCa radiosensitization. High blood levels of glutamine in PCa patients significantly correlate with a shorter prostate-specific antigen (PSA) doubling time. Furthermore, high expression of critical regulators of glutamine metabolism, GLS1 and MYC, is significantly associated with a decreased progression-free survival in PCa patients treated with radiotherapy. Our findings demonstrate that GLS-driven glutaminolysis is a prognostic biomarker and therapeutic target for PCa radiosensitization.

cancer biology↗