Biology subjects

Poli, A.

Publications and source records attributed to Poli, A..

9 recordsLinked to original sources

bioRxiv2026

Maternal behavioral compensation after neonatal separation fails to prevent spinal circuit reprogramming in offspring

Early-life adversity durably alters neural development through complex mother-offspring interactions whose underlying mechanisms remain poorly understood. We investigated how neonatal maternal separation (NMS) affects the large repertoire of maternal behaviors and subsequently influences spinal nociceptive circuit development and pain responses in rat offspring. Rat dams underwent NMS from postnatal day 2 (P2) to P12, 3h/day, and maternal behaviors were assessed before and after the separation period. These behaviors were compared to those of control (non-separated) dams. Offspring spinal cord and dorsal root ganglia were analyzed at P14 and P24 for several neurotrophic, glutamatergic, and GABAergic gene expression patterns. Offspring nociceptive sensitivity was also assessed at P24. NMS induced increased maternal behaviors (including longer arched-back nursing, higher nest occupancy, and better pup retrieval efficiency), alongside reduced self-care behaviors. These behavioral adaptations were correlated with spinal gene reprogramming in offspring, characterized by a biphasic developmental pattern. At P14, we observed elevated neurotrophic signaling alongside increased GABAergic and glutamatergic markers. By P24, neurotrophic factors decreased while compensatory changes emerged, yet persistent excitatory-inhibitory imbalances remained evident. Parallel to these results, NMS rats also showed mechanical and thermal hot hypersensitivity at P24. These findings reveal that despite apparent maternal behavioral compensation following NMS, offspring exhibit neurotrophic-driven developmental dysregulation resulting in persistent spinal circuit alterations. The disconnect between maternal behavioral normalization and sustained molecular changes suggests that early separation stress triggers enduring neurobiological cascades independent of ongoing maternal care quantity, with long-term consequences for sensory processing and pain sensitivity. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=124 SRC="FIGDIR/small/736384v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1769b63org.highwire.dtl.DTLVardef@1d396dforg.highwire.dtl.DTLVardef@5647eeorg.highwire.dtl.DTLVardef@8c8db8_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2026

Circulating immune profiling reveals impaired monocyte states and trajectories driving immunosuppression in glioblastoma

Glioblastoma (GBM) is an aggressive and lethal brain tumor marked by profound local and systemic immune dysfunction. Yet, the diagnostic and therapeutic relevance of peripheral impairments remains undefined. To clinically dissect their underlying mechanisms and pathological implications, we combined mass and flow cytometry with single-cell RNA-sequencing of peripheral blood mononuclear cells from GBM patients and healthy donors. GBM blood profiles were characterized by heterogeneous changes in classical monocytes, encompassing expanded, reduced and unchanged subsets, presenting distinct functional states, including antigen-presenting, interferon and metabolic subsets. Additional adaptations included myeloid-derived suppressor cell (MDSC) expansion and loss of non-classical monocytes. Trajectory analyses positioned MDSCs as an intermediate state, in continuum with the metabolic subset. Single-cell RNA-sequencing further showed antigen-presenting monocyte propensity to differentiate into tumor-associated macrophages. Circulating monocytes shared a "GBM-classical monocytic signature" exhibiting low MHC class II expression, altered cell-cell communication and increased anti-inflammatory mediators, such as IL1R2 and CD163. Lastly, lymphocyte alterations included decreased proportions of CD4+ T, natural killer (NK) and CD56+ T cells, retaining relatively conserved activation profiles, exemplified by up-regulation of alarmins S100A8/S100A9. These findings map systemic immune reprogramming in GBM, suggesting new avenues for non-invasive biomarker discovery and therapeutic strategies to restore anti-tumor immunity.

cancer biology↗

bioRxiv2025

Humanized glioblastoma patient-derived orthotopic xenografts recreate a locally immunosuppressed human immune ecosystem amenable to immunotherapeutic modulation

Immune-based strategies have so far failed to demonstrate clinical benefit in glioblastoma (GBM), largely due to the profound immunosuppressive tumor microenvironment (TME). To achieve more predictive preclinical insights, advanced in vivo models that faithfully recapitulate the human brain immune landscape are urgently needed. Here, we established GBM patient-derived orthotopic xenografts (PDOXs) across diverse mouse strains, including humanized models. Humanization was achieved through transplantation of CD34+ hematopoietic stem cells (HU-CD34+) or peripheral blood mononuclear cells (HU-PBMC). Both models successfully reconstituted human T-cells systemically, with stronger engraftment in HU-CD34+ mice. We observed selective infiltration and spatial organization to intracranial GBM tumors, including exhausted, memory-like, and regulatory CD4+ T-cell phenotypes, TIM-3+ immunosuppressive-like myeloid cells and intratumoral B cells. Mouse microglia-derived tumor-associated macrophages (TAMs) remained the dominant immunosuppressive immune population. Anti-PD-1 therapy, but not anti-GITR, modestly modulated the infiltration dynamics, demonstrating the susceptibility of the reconstructed adaptive immunity to immunotherapeutic intervention. These findings position humanized GBM PDOXs as a relevant preclinical platform to interrogate tumor-immune interactions and evaluate immunotherapeutic strategies in a human context. Key pointsO_LIGBM PDOXs developed in HU-CD34+ and HU-PBMC mice faithfully reconstitute systemic and local human adaptive immunity. C_LIO_LIHuman immune components undergo selective infiltration, spatial organization and transition towards exhausted CD4+ T-cells and immunosuppressive CD11c+ myeloid cells. C_LIO_LIAnti-PD-1, but not anti-GITR, locally promote human immune infiltration into intracranial GBM tumors, while sparing systemic compartments. C_LIO_LIHumanized GBM PDOXs provide a powerful preclinical platform to test novel immunotherapeutic strategies. C_LI Study importanceImmune checkpoint blockade has shown limited efficacy in GBM, reflecting the highly immunosuppressive and lymphocyte-poor nature of the TME. Conventional syngeneic and GEMM models fail to recapitulate these features, contributing to the translational disconnect between preclinical success and clinical failure. Humanized mice provide a solution to interrogate human-specific immunity in vivo, but their use in GBM has remained limited. Here, we provide the first comparison of GBM PDOX modeling in two complementary modes of humanization based on CD34+ HSCs and PBMCs. We systematically profile systemic and intratumoral compartments, showing that these models faithfully reconstitute human adaptive immunity and capture the interplay with the murine brain TME. Furthermore, we demonstrate clinically-relevant responses upon treatment with checkpoint antibodies targeting PD-1 and GITR, showing modulation of human immune subsets without altering murine TAM immunosuppression, underscoring the translational value of the system. This study establishes humanized GBM PDOXs as a versatile platform for dissecting tumor-immune interactions in the brain and for preclinical evaluation and development of novel immunotherapies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/689484v2_ufig1.gif" ALT="Figure 1"> View larger version (74K): org.highwire.dtl.DTLVardef@1b684e1org.highwire.dtl.DTLVardef@1cdfbbdorg.highwire.dtl.DTLVardef@4a570borg.highwire.dtl.DTLVardef@98b112_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2024

Chromatin condensates tune nuclear mechano-sensing in Kabuki Syndrome by constraining cGAS activation

Cells and tissue integrity is constantly challenged by the necessity to adapt and respond to mechanical loads. Among the cellular components, the nucleus possesses mechano-sensing and mechanotransduction capabilities, yet the molecular mechanisms involved remain poorly defined. We postulated that the mechanical properties of the chromatin and its compartmentalization into condensates contribute to the nuclear adaptation to external forces, while preserving its integrity. By interrogating the effects of MLL4 loss-of-function in Kabuki Syndrome, we found that the balancing of transcriptional and Polycomb condensates tunes the nuclear responsiveness to external mechanical forces. We showed that MLL4 acts as a chromatin mechano-sensor by clustering into condensates through its Prion-like domain, and its response was regulated by the chromatin context. Furthermore, the mechano-sensing activity of MLL4 condensates is instrumental to withstand the physical challenges that nuclei experience during cell confinement and migration by preserving their integrity. In Kabuki Syndrome persistent rupture of nuclear envelope triggers cGAS-STING activation, which leads to programmed cell death. Ultimately, these results demonstrate the critical role chromatin compartments play in mechano-responses and how they impact pathological conditions by stimulating cGAS-STING signaling.

molecular biology↗

bioRxiv2024

Adenoviral Delivery of the CIITA Transgene Induces T-Cell-Mediated Killing in Glioblastoma Organoids

The immunosuppressive nature of the tumor microenvironment poses a significant challenge to effective immunotherapies against glioblastoma (GB). Boosting the immune response is critical for a successful therapy. Here, we adopted a cancer gene therapy approach to induce T-cell mediated killing of the tumor through increased activation of the immune system. Patient-based 3D GB models were infected with a replication-deficient adenovirus (AdV) armed with the Class II Major Histocompatibility Complex (MHC-II) Transactivator CIITA gene (Ad-CIITA). Successful induction of surface MHC-II was achieved in infected GB cell lines and primary human GB organoids. Infection with an AdV carrying a mutant form of CIITA with a single amino acid substitution resulted in cytoplasmic accumulation of CIITA without subsequent MHC-II expression. Co-culture of infected tumor cells with either PBMCs or isolated T-cells led to dramatic breakdown of GB organoids. Intriguingly, both wild-type and mutant Ad-CIITA but not unarmed AdV, triggered immune-mediated tumor cell death in the co-culture system, suggesting an at least partially MHC-II-independent process. We further show that the observed cancer cell killing requires the presence of either CD8+ or CD4+ T-cells and the direct contact between GB and immune cells. We did not however detect evidence of activation of canonical T-cell mediated cell death pathways. While the precise mechanism remains to be determined, these findings highlight the potential of AdV-mediated CIITA delivery to enhance T-cell-mediated immunity against GB.

cancer biology↗

bioRxiv2023

Glioblastoma-instructed microglia transit to heterogeneous phenotypic states with phagocytic and dendritic cell-like features in patient tumors and patient-derived orthotopic xenografts

BackgroundA major contributing factor to glioblastoma (GBM) development and progression is its ability to evade the immune system by creating an immune-suppressive environment, where GBM-associated myeloid cells, including resident microglia and peripheral monocyte-derived macrophages, play critical pro-tumoral roles. However, it is unclear whether recruited myeloid cells are phenotypically and functionally identical in GBM patients and whether this heterogeneity is recapitulated in patient-derived orthotopic xenografts (PDOXs). A thorough understanding of the GBM ecosystem and its recapitulation in preclinical models is currently missing, leading to inaccurate results and failures of clinical trials. MethodsHere, we report systematic characterization of the tumor microenvironment (TME) in GBM PDOXs and patient tumors at the single-cell and spatial levels. We applied single-cell RNA-sequencing, spatial transcriptomics, multicolor flow cytometry, immunohistochemistry and functional studies to examine the heterogeneous TME instructed by GBM cells. GBM PDOXs representing different tumor phenotypes were compared to glioma mouse GL261 syngeneic model and patient tumors. ResultsWe show that GBM tumor cells reciprocally interact with host cells to create a GBM patient-specific TME in PDOXs. We detected the most prominent transcriptomic adaptations in myeloid cells, with brain-resident microglia representing the main population in the cellular tumor, while peripheral-derived myeloid cells infiltrated the brain at sites of blood-brain barrier disruption. More specifically, we show that GBM-educated microglia undergo transition to diverse phenotypic states across distinct GBM landscapes and tumor niches. GBM-educated microglia subsets display phagocytic and dendritic cell-like gene expression programs. Additionally, we found novel microglial states expressing cell cycle programs, astrocytic or endothelial markers. Lastly, we show that temozolomide treatment leads to transcriptomic plasticity and altered crosstalk between GBM tumor cells and adjacent TME components. ConclusionOur data provide novel insights into the phenotypic adaptation of the heterogeneous TME instructed by GBM tumors. We show the key role of microglial phenotypic states in supporting GBM tumor growth and response to treatment. Our data place PDOXs as relevant models to assess the functionality of the TME and changes in the GBM ecosystem upon treatment. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=127 SRC="FIGDIR/small/531162v2_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@1549a3corg.highwire.dtl.DTLVardef@159f16aorg.highwire.dtl.DTLVardef@1f89500org.highwire.dtl.DTLVardef@fe6b67_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2022

Force-biased nuclear import sets nuclear-cytoplasmic volumetric coupling by osmosis

In eukaryotes, cytoplasmic and nuclear volumes are tightly regulated to ensure proper cell homeostasis. However, the detailed mechanisms underlying nucleus-cytoplasm volumetric coupling remain unknown. Recent evidence supports a primary role of osmotic mechanisms in determining a tight link between nuclear and cytoplasmic volume, but this hypothesis remains largely untested in mammalian cells. We approach the question in single cultured adhering human cells, by jointly measuring cytoplasmic and nuclear volumes, in real time and across cell cycles. Surprisingly, we find that cytoplasmic and nuclear volumes follow different average growth laws: while the cytoplasm grows exponentially, the nucleus grows linearly. Moreover, by combining several experimental perturbations and analyzing a mathematical model including osmotic effects and tension, we conclude that the mechanical forces exerted by the cytoskeleton on the nuclear envelope can strongly affect nucleus-cytoplasm volumetric coupling by biasing nuclear import. Our results unveil how osmo-mechanical equilibrium regulates nuclear size in mammalian cells. One-Sentence SummaryCytoskeletal forces exerted on the nuclear envelope impact on nuclear volume through modulation of force-coupled nucleo-cytoplasmic transport, affecting osmosis.

cell biology↗

bioRxiv2022

PIP4K2B is a mechanosensor and induces heterochromatin-driven nuclear softening through UHRF1.

Phosphatidylinositol-5-phosphate (PtdIns5P)-4-kinases (PIP4Ks) are stress-regulated phosphoinositide kinases able to phosphorylate PtdIns5P to PtdIns(4, 5)P2. In cancer patients their expression is typically associated with bad prognosis. Among the three PIP4K isoforms expressed in mammalian cells, PIP4K2B is the one with more prominent nuclear localization. Here, we unveil the role for PIP4K2B as mechanosensor. PIP4K2B protein level, indeed, strongly decreases in cells growing on soft substrates. Its direct silencing or pharmacological inhibition, mimicking cell response to soft, triggers a concomitant reduction of the epigenetic regulator UHRF1 and induces changes in nuclear polarity, nuclear envelope tension and chromatin compaction. This substantial rewiring of the nucleus mechanical state drives YAP cytoplasmic retention and impairment of its activity as transcriptional regulator, finally leading to defects in cell spreading and motility. Since YAP signalling is essential for initiation and growth of human malignancies, our data suggest that potential therapeutic approaches targeting PIP4K2B could be beneficial in the control of the altered mechanical properties of cancer cells.

cell biology↗

bioRxiv2020

FAM13A regulates maturation and effector functions of natural killer cells

The polymorphism of the gene FAM13A (family with sequence similarity 13, member A) is strongly linked to the risk of lung cancer and chronic obstructive pulmonary disease, which are among the leading causes of mortality and morbidity in lung-related diseases worldwide. However, the underlying molecular and cellular mechanisms through which FAM13A contributes to the pathogenesis of these diseases largely remain unclear. Here, using a Fam13a knock out (KO) mouse model, we showed that Fam13a depletion upregulated the expression of the terminal differentiation and inhibitory marker, KLRG1 (killer cell lectin-like receptor G1) in natural killer (NK) cells. NK cells from Fam13a-deficient mice showed impaired IFN-{gamma} production either against target tumor cells or following various cytokine cocktail stimulations. Furthermore, the number of lung metastases induced by B16F10 melanoma cells was increased in Fam13a-KO mice. Collectively, our data suggest a key role of FAM13A in regulating NK cell functions, indicating that the key lung-disease risk gene FAM13A might contribute to the pathogenesis of several lung diseases via regulating NK cells.

immunology↗