Biology subjects

Serrano, B.

Publications and source records attributed to Serrano, B..

4 recordsLinked to original sources

bioRxiv2025

Mutations in specific MT5-MMP domains prevent the accumulation of toxic APP metabolites and serve as templates for peptide-based therapeutics in cell models of Alzheimer's disease

Our prior work established a pivotal role for membrane-type 5-matrix metalloproteinase (MT5-MMP) in Alzheimers disease (AD) pathogenesis, particularly through its C-terminal transmembrane (TM) and intracellular (IC) domains, which influence the fate of major toxic metabolites of toxic amyloid precursor protein (APP) metabolites, particularly C99 and A{beta}. Hypothesizing that modifications in these domains could modulate C99 and A{beta} levels, we engineered MT5-MMP variants with deletions or substitutions in the TM/IC domains or specific IC amino acid clusters. When co-transfected into human cell lines accumulating C99, certain IC domain mutations promoted C99 degradation and reduced A{beta} levels, while other mutations had divergent effects. High content imaging further revealed that MT5-MMP IC domain modification altered C99 subcellular trafficking within the endomembrane system, impacting its processing. Proximity ligation assays confirmed the importance of the IC domain in MT5-MMP colocalization and potential interaction with C99. To translate these findings, we synthetized peptides mimicking the MT5-MMP IC domain, incorporating mutations that reduce C99 and/or A{beta} levels. One peptide effectively lowered C99 levels in an in vitro AD model. Overall, this study highlights the importance of specific amino acids in the C-terminal domains of MT5-MMP for regulating C99 and A{beta} metabolism. It also provides new insights for developing MT5-MMP-based therapeutic strategies against AD, exploiting the unique properties of specific mutations in MT5-MMP to prevent toxic accumulation of C99 and A{beta}. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=86 SRC="FIGDIR/small/655451v3_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@a6b04aorg.highwire.dtl.DTLVardef@1800721org.highwire.dtl.DTLVardef@542505org.highwire.dtl.DTLVardef@4a6d7b_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGRAPHICAL ABSTRACTC_FLOATNO C_FIG

cell biology↗

bioRxiv2025

Identification and optimization of trans-species reactive TfR1-binding VHH as tools for drug delivery across the blood brain barrier

The blood-brain barrier (BBB) is a major obstacle for delivering therapeutic agents to the central nervous system (CNS), posing significant challenges for treating neurological disorders. Among current strategies to improve brain drug exposure, hijacking physiological pathways involved in receptor-mediated transcytosis (RMT) has emerged as a promising strategy. While targeting transferrin receptor 1 (TfR1) is widely explored, many TfR1-antibodies lack cross-species reactivity, limiting translational development. In the present study, we identified and characterized camelid-derived single-domain antibodies (VHHs) with robust cross-reactivity to rodent, rhesus monkey, and human TfR1. Epitope mapping of the VHH revealed a novel binding site at the interface of the TfR1 dimer. When fused to a human IgG1 Fc domain, these VHHs, as monomers or homodimers, were efficiently internalized by engineered CHO cells and brain endothelial cells expressing TfR1 from different species. Systemic administration of VHH-Fc constructs in mice demonstrated significantly improved brain uptake compared to irrelevant controls. Functional delivery was confirmed using neurotensin (NT)-induced hypothermia, and we established correlations between in vivo effects and TfR1 VHH binding properties determined by surface plasmon resonance. Notably, efficient BBB transcytosis was associated with intermediate affinity and rapid dissociation rates. Engineered variants maintained favorable cross-species binding, including similar affinities to human and non-human primate TfR1, facilitating translational studies. The cross-reactive anti-TfR1 VHHs we developed offer a versatile and modular platform for CNS drug delivery and hold promise as molecular shuttles for transporting therapeutic agents across the BBB. Our work establishes a robust foundation for developing next-generation brain-targeted biotherapeutics, including peptides, enzyme replacement therapies, antibody-based treatments for neurodegenerative diseases, and oligonucleotide delivery for CNS disorders, enabling seamless translation from preclinical to clinical applications.

neuroscience↗

bioRxiv2023

Integrin-alpha V beta 3 is a fundamental factor in medulloblastoma tumorigenicity and radioresistance: A new game for an old player

Medulloblastoma (MB) is the most frequent solid tumor in children, localized in the brains posterior fossa. Its standard of care comprises maximal resection surgery followed by craniospinal irradiation and chemotherapy. Despite a long-term survival rate of 70%, wide disparities among patients have been observed. Relevant targets for naive and recurrent MB are urgently needed. Primary and recurrent MBs are characterized by aggressive invasion into surrounding brain tissue, active angiogenesis, and radioresistance. Integrin-v{beta}3 was a major driver of these features in glioblastoma. Nevertheless, such observations have not yet been reported in MB. Integrin-v{beta}3 was found to be expressed in a subset of MB patients. We investigated the role of integrin-v{beta}3 using MB-derived cell lines with {beta}3-subunit depletion or overexpression both in vitro and in vivo. Radioresistant MB cell lines were generated and showed increased integrin-v{beta}3 expression, which correlated with increased susceptibility to pharmacological integrin-v{beta}3 inhibition with cilengitide, a competitive ligand mimetic. Finally, we conducted single-photon emission computed tomography (SPECT)/magnetic resonance imaging (MRI) studies on orthotopic models using a radiolabeled integrin-v{beta}3 ligand (99mTc-RAFT-RGD). This approach offers the prospect of a novel predictive imaging modality in MB. Altogether, our data pave the way for SPECT/MRI-based selection of a subpopulation of MB patients eligible for integrin-v{beta}3-directed therapies. SIGNIFICANCEThis study demonstrates integrin-v{beta}3s fundamental role in MB tumorigenicity and radioresistance and the effect of its expression on cilengitide functional activity.

cancer biology↗

bioRxiv2022

Pre-B cell receptor acts as a selectivity switch for Galectin-1 at the pre-B cell surface

Galectins are glycan binding proteins translating the sugar-encoded information of cellular glycoconjugates into many physiological activities including immunity, cell migration, and signaling. During early B lymphocytes (BL) development at the pre-B cell stage, BL express the pre-B cell receptor (pre-BCR) and are supported by mesenchymal stromal cells secreting Galectin-1 (Gal-1). Gal-1 interacts with glycosylated receptors from stromal and pre-B cell surfaces but also with the pre-BCR through a direct carbohydrate-independent contact. How this interaction might interplay with the glycan-decoding function of Gal-1 is unknown. Here, we investigated Gal-1 binding to cell surface ligands using NMR spectroscopy on native membranes. We showed that pre-BCR regulates Gal-1 binding to specifically target 2,3-sialylated receptors on pre-B cells. Upon pre-BCR interaction, dynamic changes resulted in additional contacts with 2,3-sialylated glycans converting Gal-1 from an exo- to an endo-type lectin. Remarkably, this selectivity switch is able to promote pre-B cell survival. Altogether, we shed light on a new mechanism allowing fine-tuning of Galectin specificity at the cell surfaces.

biochemistry↗