Biology subjects

Ulivieri, C.

Publications and source records attributed to Ulivieri, C..

3 recordsLinked to original sources

bioRxiv2025

Thrombospondin Encapsulated Dense Particles accelerate wound healing and downregulate fibrotic phenotypes

Extracellular particles (EP) released by cells are heterogenous, with extracellular vesicles (EV) believed to be the major component. To investigate different EV subpopulations, we conducted a panel screen of 15 fluorescent EV markers in 4 adherent cell lines. Nanoflow cytometry identifies TSPAN14 as the best EV marker in 3 of 4 cell lines. Surprisingly, less than 50% of EPs are labelled by the top 2 EV markers in half the cell lines. The EV marker negative EPs are detergent resistant, non-lipophilic, dense and have Thrombospondin shells by dSTORM; and were thus named Thrombospondin Encapsulated Dense particles (ThrEDs). ThrEDs are ubiquitous, contain extracellular matrix regulators and are released following cell stress. ThrEDs accelerate scratch-wound closure and downregulate the fibrotic phenotype in Dupuytrens disease patient myofibroblasts. The TSP-1 C-terminus is exposed on the surface of ThrEDs, opening engineering applications.

cell biology↗

bioRxiv2023

Leukemic cell-secreted interleukin-9 suppresses cytotoxic T cell-mediated killing in chronic lymphocytic leukemia

The tumor microenvironment (TME) plays a central role in the pathogenesis of chronic lymphocytic leukemia (CLL), contributing to disease progression and chemoresistance. Leukemic cells shape the TME into a pro-survival and immunosuppressive niche through contact-dependent and contact-independent interactions with the cellular components of the TME. Immune synapse (IS) formation is defective in CLL. Here we asked whether soluble factors released by CLL cells contribute to their protection from cytotoxic T cell (CTL)-mediated killing by interfering with this process. We found that healthy CTLs cultured in media conditioned by leukemic cells from CLL patients or E-TCL1 mice upregulate the exhaustion marker PD-1 and become unable to form functional ISs and kill target cells. These defects were more pronounced when media were conditioned by leukemic cells lacking p66Shc, a proapoptotic adaptor whose deficiency has been implicated in disease aggressiveness both in CLL and in the E-TCL1 mouse model. Multiplex ELISA assays showed that leukemic cells from E-TCL1 mice secrete abnormally elevated amounts of CCL22, CCL24, IL-9 and IL-10, which are further upregulated in the absence of p66Shc. Among these, IL-9 and IL-10 were also overexpressed in leukemic cells from CLL patients, where they inversely correlated with residual p66Shc. Using neutralizing antibodies or the recombinant cytokines we show that IL-9, but not IL-10, mediates both the enhancement in PD-1 expression and the suppression of effector functions in healthy CTLs. Our results demonstrate that IL-9 secreted by leukemic cells negatively modulates the anti-tumor immune abilities of CTLs, highlighting a new suppressive mechanism and a novel potential therapeutical target in CLL.

cancer biology↗

bioRxiv2023

Human colorectal cancer: upregulation of the adaptor protein Rai in TILs leads to cell dysfunction by sustaining GSK-3 activation and PD-1 expression

BackgroundThe immunosuppressive tumor microenvironment (TME) of colorectal cancer (CRC) is a major hurdle for immune checkpoint inhibitor-based therapies. Hence characterization of the signaling pathways driving T cell exhaustion within TME is a critical need for the discovery of novel therapeutic targets and the development of effective therapies. We previously showed that i) the adaptor protein Rai is a negative regulator of T cell receptor signaling and T helper 1 (Th1)/Th17 cell differentiation; and ii) Rai deficiency is implicated in the hyperactive phenotype of T cells in autoimmune diseases. MethodsThe expression level of Rai was measured by qRT-PCR in paired peripheral blood T cells and T cells infiltrating tumor tissue and the normal adjacent tissue in CRC patients. The impact of HIF-1 on Rai expression was evaluated in T cells exposed to hypoxia and by performing chromatin immunoprecipitation assays and RNA interference assays. The mechanism by which upregulation of Rai in T cells promotes T cell exhaustion were evaluated by flow cytometric, qRT-PCR and western blot analyses. ResultsWe show that Rai is a novel HIF-1-responsive gene that is upregulated in tumor infiltrating lymphocytes of CRC patients compared to patient-matched circulating T cells. Rai upregulation in T cells promoted PD-1 expression and impaired antigen-dependent degranulation of CD8+ T cells by inhibiting phospho-inactivation of glycogen synthase kinase (GSK)-3, a central regulator of PD- 1 expression and T cell-mediated anti-tumor immunity. ConclusionsOur data identify Rai as a hitherto unknown regulator of the TME-induced exhausted phenotype of human T cells. What is already known on this topicO_LITumor hypoxia contributes to establish an immunosuppressive microenvironment that unleashes T cell function and limits the efficacy of immunotherapy in CRC. C_LIO_LIThe molecular mechanisms underlying the impact of hypoxia on the signaling pathways controlling PD-1 expression are unknown. C_LI What this study addsO_LIA Rai/Akt/GSK-3 axis regulates PD-1 expression following TCR/CD28 co-stimulation C_LIO_LIThis study uncovers the signaling pathway controlling hypoxia-dependent T cell exhaustion. C_LI How this study might affect research, practice or policyRai expression levels in TILs of CRC patients might be explored as a potential new biomarker of T cell exhaustion and a predictive biomarker for anti-PD-1 response.

cancer biology↗