Biology subjects

Guerra, L.

Publications and source records attributed to Guerra, L..

5 recordsLinked to original sources

bioRxiv2026

alpha2,3-sialylation on human naive T cells restrains bispecific engager-mediated anti-tumor immunity

Aberrantly elevated cell-surface sialylation, or hypersialylation, is a common feature of human cancers and contributes to immune evasion. Sialidase-based therapies have therefore emerged as a strategy to disrupt this glyco-checkpoint. Although the immunosuppressive role of tumor-associated sialylation is well established, how sialylation on human T cells shapes anti-tumor responses remains poorly defined. Here, we identify surface sialoglycans on T cells, particularly 2,3-linked structures, as a cell-intrinsic restraint on human T cell activation, proliferation, and effector function. In vitro, enzymatic desialylation enhanced T cell activation, proliferation, cytokine production, and bispecific T cell engager (TCE)-mediated tumor-cell killing in healthy donor PBMC co-cultures. In ex vivo cultures of primary chronic lymphocytic leukemia (CLL) PBMCs, sialidase treatment combined with the CD20-directed TCE glofitamab enhanced cytotoxic effector transcriptional programming in autologous T cells. Single-cell RNA sequencing combined with lectin-based CITE-seq linked treatment-induced transcriptional states to lectin-defined cell-surface glycan signatures within the same single-cell dataset. This integrated analysis revealed that naive and, to a lesser extent, central memory T cells combined elevated baseline 2,3-sialylation signatures with the clearest transcriptional responses to glofitamab plus sialidase treatment. CD43 emerged as a major carrier of 2,3-linked sialoglycans, and its deletion attenuated sialidase-enhanced T cell activation. Together, these findings identify sialylation of the T cell surface as a subset-specific restraint on human TCE responses and provide a rationale for testing sialidase-TCE combinations designed to engage less-differentiated T cell populations. One-sentence summaryDesialylation enhances bispecific T cell engager responses by relieving a sialoglycan-dependent restraint in human T cells.

immunology↗

bioRxiv2025

Activating RET Mutations Promotes Osteoblastic Bone Metastases in Medullary Thyroid Cancer

Development of bone metastases increases mortality in patients with medullary thyroid cancer (MTC), with [~]50% survival at 5 years after diagnosis, but the underlying mechanisms are unknown. We show that patient-derived MTC cells (RETC634W mutant TT cells and RETM918T mutant MZCRC1 cells) promote an osteoblastic phenotype due to reduced bone resorption. Mechanistically, activated RET increases the expression of osteoprotegerin (OPG), an inhibitor of bone resorption, leading to decreased osteoclast differentiation. Furthermore, RET knockdown or pharmacological RET inhibition attenuates tumor burden and osteoblastic lesions in MTC-bearing femurs. Circulating levels of OPG were increased in the plasma of MTC patients who developed bone metastases and this was associated with poor overall survival. Patients who were treated with multi-kinase inhibitors have lower circulating levels of OPG. These novel findings identify a link between the RET signaling pathway and abnormal osteoblastic bone formation and suggest OPG as a potential biomarker of MTC bone metastases. HighlightsO_LIPatient-derived MTC cells promote osteoblastic lesions in a mouse model. C_LIO_LIActivating the RET mutation promotes osteoprotegerin. C_LIO_LIBlocking RET kinase activity inhibits tumor growth and the osteoblastic lesion phenotype. C_LIO_LIHigh levels of circulating osteoprotegerin are associated with poor overall survival. C_LI

cancer biology↗

bioRxiv2023

A Th17 cell-intrinsic glutathione/mitochondrial-IL-22 axis protects against intestinal inflammation

Although the intestinal tract is a major site of reactive oxygen species (ROS) generation, the mechanisms by which antioxidant defense in gut T cells contribute to intestinal homeostasis are currently unknown. Here we show, using T cell-specific ablation of the catalytic subunit of glutamate cysteine ligase (Gclc), that the ensuing loss of glutathione (GSH) impairs the production of gut-protective IL-22 by Th17 cells within the lamina propria. Although Gclc ablation does not affect T cell cytokine secretion in the gut of mice at steady-state, infection with C. rodentium increases ROS, inhibits mitochondrial gene expression and mitochondrial function in Gclc-deficient Th17 cells. These mitochondrial deficits affect the PI3K/AKT/mTOR pathway, leading to reduced phosphorylation of the translation repressor 4E-BP1. As a consequence, the initiation of translation is restricted, resulting in decreased protein synthesis of IL-22. Loss of IL-22 results in poor bacterial clearance, enhanced intestinal damage, and high mortality. ROS-scavenging, reconstitution of IL-22 expression or IL-22 supplementation in vivo prevent the appearance of these pathologies. Our results demonstrate the existence of a previously unappreciated role for Th17 cell-intrinsic GSH coupling to promote mitochondrial function, IL-22 translation and signaling. These data reveal an axis that is essential for maintaining the integrity of the intestinal barrier and protecting it from damage caused by gastrointestinal infection. Executive summary- GSH-regulated Th17 cell-derived IL-22, but not IL-17 is required to maintain intestinal barrier integrity and to revent lethality following C. rodentium infection. - GCLC expression in IBD patients correlates positively with expression of genes related to gut integrity. - Gclc-deficient Th17 cells accumulate mitochondrial ROS, which is linked to impaired mitochondrial function, ysregulated PI3K/AKT/mTOR signaling and impaired translation of IL-22. - ROS-scavenging, IL-22 reconstitution or T cell-specific expression of IL-22 in Gclc-deficient T cells rescues utant mice from the lethal infection outcome in vivo.

immunology↗

bioRxiv2022

Plasmodium exoerythrocytic parasites redirect trafficking of human proteins to the parasitophorous vacuole

Changes in host cell morphology and transcription after apicomplexan parasite infection have long been noted, but there have been few studies of the functional consequences of host cell remodeling. Here we show, using time-dependent immunofluorescence microscopy of multiple human cell lines (HepG2, HC-04, Huh7.5.1 and primary human hepatocytes), infected with multiple Plasmodium species (Plasmodium berghei, P. falciparum and P. vivax (hypnozoites and schizonts)), and antibodies to multiple human proteins (HsNR4A3, HsMUC13, HsGOLGA8A, HsCGA, HsBiP, HsCXCL2), that human protein trafficking is extensively modified in Plasmodium infected cells. Using conventional as well as ultrastructure expansion microscopy we show that newly-synthesized human proteins are trafficked to the parasitophorous vacuole instead of the infected-cell plasma membrane, nucleus or extracellular space. Universal redirection of human signaling proteins cells the parasitophorous vacuole may provide a mechanistic explanation for how apicomplexan parasites can block host cells response to infection.

cell biology↗

bioRxiv2022

Camel urine limits proliferation and modifies cell morphology in human renal tumoral and non-tumoral cells

The widespread ethnomedical practice of dromedary urinotherapy as a remedy against various illnesses is well recognized in traditional dromedary countries, and multiple researchers tried to unravel its bioactive potential and provide scientific evidence through in vivo and in vitro experiments. None of these studies (i) measured urine osmolarity prior to bioactivity testing, which could deeply influence the results of in vitro tests, nor (ii) addressed issues related to cells morphological changes after exposure to camel urines. Taken together, the above aspects point to the need for a "good practice" to be shared by researchers in this field, in order to reduce the variability of in vitro testing of camel urine bioactivity. In this work, using a set of biological samples from animals differing in sex, age, and physiological status, we investigated, the antiproliferative activity of camel urine towards human non-tumoral (HK2) and tumoral renal cells (Caki-1), through cell viability and microscopy analysis, and taking the possible influence of osmolarity into account. We employed cell lines commonly used in toxicological research which, to the best of our knowledge, have not been previously exposed to camel urine. HK2 and Caki-1 cells tolerated well mannitol-induced hyperosmolarity up to 500 mOsm/L. Significant antiproliferative effects were observed only in Caki-1 cells, when exposed to urine solutions (diluted to <500 mOsm/L) from two males out of the ten tested samples, while effects on cell morphology (elongation) were observed only in HK2 cells, when exposed to urine solutions from six samples. The significant antiproliferative effect observed only in tumoral cells looks promising for forthcoming developments in the cancer treatment field. Finally, the presented approach may serve as a guide for future research in this specific, multidisciplinary field.

cell biology↗