Biology subjects

Serra, C.

Publications and source records attributed to Serra, C..

5 recordsLinked to original sources

bioRxiv2025

Photocaged chloroquine derivatives for the light-dependent inhibition of autophagy in cancer stem cells

Chloroquine (CQ) and hydroxychloroquine (HCQ) inhibit autophagy and have shown promise as adjuvant anticancer agents, particularly for targeting therapy-resistant cancer stem cells (CSCs). However, their clinical utility is limited by systemic toxicity and poor tumour selectivity. Here we report the design, synthesis, and photochemical evaluation of [7-(diethylamino)coumarin-4-yl]methyl (DEACM)-caged CQ and HCQ derivatives as visible-light-activated autophagy inhibitors. Selective caging of the aliphatic amine fully suppressed biological activity in the dark and enabled rapid, efficient release of the parent drugs upon illumination. The lead compound 1C displayed robust light-dependent cytotoxicity across multiple cancer cell lines and, upon photoactivation, recapitulated CQs effects on LC3-II accumulation. In CSC-enriched tumourspheres, illumination of 1C completely abolished spheroid formation, demonstrating precise spatiotemporal control of stemness suppression. Importantly, ex vivo and in vivo studies confirmed that visible light penetrates tumour tissue sufficiently to activate 1C and release CQ within the tumour. These findings establish the first proof of concept for light-controlled autophagy inhibition and provide a blueprint for spatiotemporally confined anticancer therapies based on photopharmacological modulation of CSCs.

cancer biology↗

bioRxiv2024

Na+/Ca2+ exchanger triggers transient disruption of axon initial segments in hippocampal granule cells after brief ischemia.

The axon initial segment (AIS) is the site of action potential initiation in many cell types. The large density of Na+ channels and the small intraluminal volume of the AIS underlie the largest spike-dependent Na+ raise along the neuron. Our Na+ and Ca2+ imaging experiments in dentate granule cells reveal that the Na+/Ca2+ exchanger contributes to fast Na+ clearance at the expense of Ca2+ entry specifically at the AIS during short bursts of action potentials. The AIS is thought to be irreversibly disrupted during brain ischemia by the Ca2+-dependent protease calpain, as an early step leading to neuronal death. We find here that brief transitory ischemia produces a similar calpain-dependent disruption of the AIS in the dentate gyrus. However, this is not an irreversible process: a few days following the brief ischemic stress, intact initial segments re-appear, and calpain activity in the dentate gyrus returns to normal. Moreover, pharmacological blockade of Ca2+ entry through the Na+/Ca2+ exchanger prevents AIS disruption in vivo and in slice preparations. Our results unveil a highly dynamic anoxia driven disruption-reconstruction of AIS, which is mediated by a previously unnoticed Ca2+ entry through the Na+/Ca2+ exchanger in the axon initial segment of hippocampal granule cells.

neuroscience↗

bioRxiv2022

Identification of differential polypharmacology between the PARP inhibitor rucaparib and its major metabolite

The (poly)pharmacology of drug metabolites is seldom comprehensively characterized in drug discovery and development. However, some drug metabolites can reach high plasma concentrations and display relevant in vivo activity, which can be distinct from its parent drug. Here, we use computational and experimental methods to comprehensively characterise the kinase polypharmacology of M324, the major metabolite of the FDA-approved PARP inhibitor rucaparib. We experimentally demonstrate that M324 displays a distinct in vitro kinome profile from its parent drug, characterized by potent in vitro inhibition of GSK3A and PLK2 at clinically-relevant concentrations. These confirmed kinase activities of M324 could have potential implications for the efficacy and safety of rucaparib and therefore warrant further clinical investigation. The study reported here highlights the importance of thoroughly characterizing the activity of significant drug metabolites to better understanding drug responses in the clinic and maximally exploit the current drug arsenal in personalized and precision medicine.

pharmacology and toxicology↗

bioRxiv2022

Design and validation of the first family of photo-activatable ligands for melatonin receptors

Melatonin is a neurohormone released in a circadian manner with peak levels during the night. In mammals, melatonin mediates its effects mainly through G protein-coupled MT1 and MT2 receptors. Drugs acting on melatonin receptors are indicated for circadian rhythm- and sleep-related disorders and major depression. Pharmacological tools to study the activation of these receptors with high temporal resolution are lacking. Here, we synthesized a family of light-activatable caged melatonin compounds by covalently attaching o-nitrobenzyl (o-NB) or coumarin photocleavable groups to the N-position of melatonin. All caged compounds showed the expected decrease in binding affinity for MT1 and MT2. Among them, the o-NB derivative MCS-0382 showed the best uncaging and biological properties upon light activation with a significant increase (2.5 log left-shift) in affinity and potency in melatonin receptor binding and signaling, respectively. Generation of biologically active melatonin from MCS-0382 was further demonstrated by its ability to modulate the excitation of SCN neurons in rat brain slices. MCS-0382 is now available to study melatonin effects in a temporally controlled manner in cellular and physiological settings.

pharmacology and toxicology↗

bioRxiv2021

TAILORED DC INDUCE PROTECTIVE HIV-1 SPECIFIC POLYFUNCTIONAL CD8+ T CELLS IN THE LYMPHOID TISSUE FROM HUMANIZED BLT MICE

Effective function of CD8+ T cells and enhanced innate activation of dendritic cells (DC) in response to HIV-1 is linked to protective antiviral immunity in controllers. Manipulation of DC targeting the master regulator TANK-binding Kinase 1 (TBK1) might be useful to acquire controller-like properties. Here, we evaluated the impact of TBK1-primed DC inducing protective CD8+ T cell responses in lymphoid tissue and peripheral blood and their association with reduced HIV-1 disease progression in vivo in the humanized bone marrow, liver and thymus (hBLT) mouse model. A higher proportion of hBLT-mice vaccinated with TBK1-primed DC exhibited less severe CD4+ T cell depletion following HIV-1 infection compared to control groups. This was associated with infiltration of CD8+ T cells in the white pulp from the spleen, reduced spread of infected p24+ cells to secondary lymphoid organs and with preserved abilities of CD8+ T cells from the spleen and blood of vaccinated animals to induce specific polyfunctional responses upon antigen stimulation. Therefore, TBK1-primed DC might be an useful tool for subsequent vaccine studies. Author summaryEmulating protective immunological characteristics from individuals capable of spontaneously controlling HIV-1 infection might be useful for the development of a protective vaccine. Enhanced function of dendritic cells (DC) in these HIV-1 controllers depends on the activation of TANK-binding Kinase 1 (TBK1) and might associate with protective T cells. Our study evaluated the ability of DCs trained through TBK1 activation inducing protective adaptive immune responses against HIV-1 and reducing disease progression in vivo, using a humanized mouse model. Our data indicate that mice vaccinated with tailored DC exhibit delayed disease progression, increased induction of protective CD8+ T lymphocyte subsets in the lymphoid tissue and blood upon antigen recognition. Therefore, trained-DC might be an useful tool for future HIV-1 vaccine designs.

immunology↗