Biology subjects

Fazio, M.

Publications and source records attributed to Fazio, M..

4 recordsLinked to original sources

bioRxiv2026

Delivery of small interfering RNA and antisense oligonucleotides across the blood-brain barrier with monovalent transferrin receptor 1 binding VHH-Fc fusion proteins

The blood-brain barrier (BBB) is a highly selective cell layer that restricts the diffusion of diverse chemical entities into the central nervous system (CNS) from systemic circulation. Macromolecular therapeutics including oligonucleotides, peptides, and monoclonal antibodies exhibit only minimal brain distribution after systemic dosing due to exclusion by the BBB. Receptor-mediated transcytosis (RMT) has evolved to transport vital cargo across the BBB through a specialized vesicular transport pathway. Transferrin receptor 1 (TfR1) shuttles transferrin, its natural ligand, across the BBB, as well as TfR1-binding IgG antibodies and conjugates. Here, we describe a novel monovalent TfR1-binding VHH-Fc for the delivery of oligonucleotide cargo, including antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs) across the BBB in rodents and non-human primates (NHPs), supporting the translational potential of the VHH-antisense RMT platform for the treatment of neurological disorders. We explore the role of binding affinity, conjugation site, drug-antibody ratio (DAR), and conjugation chemistry, and determine that binding affinity, DAR and conjugation site are major determinants of RMT capacity and brain activity of siRNAs delivered across the BBB. Graphical Abstract / Highlights O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/744307v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@d1d648org.highwire.dtl.DTLVardef@4b22d3org.highwire.dtl.DTLVardef@db8b6borg.highwire.dtl.DTLVardef@19e5ac3_HPS_FORMAT_FIGEXP M_FIG C_FIG - Anti-TfR1 (-TfR1) VHH ligands formatted as heterodimeric, 2-chain monovalent VHH-Fc were engineered for conjugation to siRNA and ASO. - Systematic in vivo evaluation of VHH clones spanning a range of TfR1 binding affinities revealed a relationship between TfR1 binding affinity and the CNS activity of intravenously dosed VHH-Fc-siRNA conjugates. - By optimizing TfR1 binding affinity, conjugation site, and conjugation chemistry, we identified VHH-Fc-siRNA molecules that efficiently cross the BBB via receptor-mediated transcytosis and reduce target mRNA across CNS tissues, including deeper brain regions, after intravenous (IV) or subcutaneous (SC) dosing in mice and non-human primates (NHPs).

neuroscience↗

bioRxiv2026

Neuronal expression of Retinoid-Related Orphan Receptor Gamma (RORγ) and revisiting its role in the Central Nervous System

Retinoid-related orphan receptor gamma (ROR{gamma}) is a lineage-defining transcription factor for T helper 17 (Th17) cells and has long been considered selectively expressed within the immune system. However, accumulating evidence has implicated Th17 cells and other ROR{gamma}-expressing immune populations in embryonic brain development and central nervous system (CNS) function. Notably, ROR{gamma}-Cre-mediated deletion of the tuberous sclerosis complex (TSC) has been reported to cause spontaneous seizures and premature lethality, leading to the conclusion that ROR{gamma}-expressing immune cells directly regulate CNS physiology. Using multiple ROR{gamma}-based reporter mouse lines, we identified unexpected and widespread neuronal labeling throughout the forebrain and cerebellum. ROR{gamma}-Cre:GFPf/ mice exhibited robust GFP expression in neurons despite the absence of detectable T cells in the brain. Neuronal recombination was evident prenatally and independently validated using the mT/mG reporter line, indicating transient ROR{gamma} expression in embryonic neurons. In contrast, a ROR{gamma}-GFP reporter showed no detectable ROR{gamma} expression in the postnatal brain, either at baseline or following pilocarpine-induced status epilepticus. These findings demonstrate that ROR{gamma} expression is not restricted to the immune lineage and reveal previously unrecognized developmental expression in the embryonic brain. Consequently, seizures observed following ROR{gamma}-Cre-mediated deletion of TSC1 are unlikely to arise from ROR{gamma}-expressing immune cell-dependent mechanisms but instead reflect direct neuronal loss of TSC1. Our results call for careful reinterpretation of prior studies attributing CNS phenotypes to ROR{gamma}-expressing immune cells based on ROR{gamma}-Cre-driven genetic models. SignificanceThis work identifies transient neuronal ROR{gamma} expression as a critical confounder in immune-targeted genetic studies and reveals a previously unrecognized embryonic expression of ROR{gamma} in neurons that may contribute to neurodevelopment. Our findings further raise the possibility that embryonic neurons represent unintended off-targets when deploying therapeutic strategies involving ROR{gamma} ligands.

neuroscience↗

bioRxiv2020

SATB2 induction of a neural crest mesenchyme-like program drives invasion and drug resistance in melanoma

Recent genomic and scRNA-seq analyses of melanoma identified common transcriptional states correlating with invasion or drug resistance, but failed to find recurrent drivers of metastasis. To test whether transcriptional adaptation can drive melanoma progression, we made use of a zebrafish mitfa:BRAFV600E;tp53-/- model, in which malignant progression is characterized by minimal genetic evolution. We undertook an overexpression-screen of 80 epigenetic/transcriptional regulators and found neural crest-mesenchyme developmental regulator SATB2 to accelerate aggressive melanoma development. Its overexpression induces invadopodia formation and invasion in zebrafish tumors and human melanoma cell lines. SATB2 binds and activates neural crest-regulators, including pdgfab and snai2. The transcriptional program induced by SATB2 overlaps with known MITFlowAXLhlgh and AQP1+NGFR1high drug resistant states and functionally drives enhanced tumor propagation and resistance to Vemurafenib in vivo. Here we show that melanoma transcriptional rewiring by SATB2 to a neural crest mesenchyme-like program can drive invasion and drug resistance in endogenous tumors.

cancer biology↗

bioRxiv2019

Cross-species analysis of melanoma enhancer logic using deep learning

Genomic enhancers form the central nodes of gene regulatory networks by harbouring combinations of transcription factor binding sites. Deciphering the combinatorial code by which these binding sites are assembled within enhancers is indispensable to understand their regulatory involvement in establishing a cells phenotype, especially within biological systems with dysregulated gene regulatory networks, such as melanoma. In order to unravel the enhancer logic of the two most common melanoma cell states, namely the melanocytic and mesenchymal-like state, we combined comparative epigenomics with machine learning. By profiling chromatin accessibility using ATAC-seq on a cohort of 27 melanoma cell lines across six different species, we demonstrate the conservation of the two main melanoma states and their underlying master regulators. To perform an in-depth analysis of the enhancer architecture, we trained a deep neural network, called DeepMEL, to classify melanoma enhancers not only in the human genome, but also in other species. DeepMEL revealed the presence, organisation and positional specificity of important transcription factor binding sites. Together, this extensive analysis of the melanoma enhancer code allowed us to propose the concept of a core regulatory complex binding to melanocytic enhancers, consisting of SOX10, TFAP2A, MITF and RUNX, and to disentangle their individual roles in regulating enhancer accessibility and activity.

genomics↗