Biology subjects

Salvador, A. M.

Publications and source records attributed to Salvador, A. M..

3 recordsLinked to original sources

bioRxiv2026

pH-dependent anti-TfR1 NANOBODY(R) molecules deliver efficacious oligonucleotide payloads to muscle and CNS tissues

The blood-brain barrier (BBB) is a highly selective, semi-permeable border of endothelial cells that prevents solutes and therapeutic agents in systemic circulation from passively crossing into the central nervous system (CNS) parenchyma. The Transferrin receptor 1 (TfR1) endocytosis pathway for iron homeostasis is one of the most well-characterized strategies for therapeutic delivery across the BBB. The work presented here showcases the discovery of novel anti-TfR1 NANOBODY(R) shuttles. The identified anti-TfR1 NANOBODY(R) molecules display cross-reactivity and pH-dependent binding to human, cynomolgus (cyno), and mouse TfR1. Structural data further explain and support the underlying mechanism of this pH-dependent binding. These anti-TfR1 NANOBODY(R) molecules were successfully conjugated to both short-interfering RNA (siRNA) and antisense oligonucleotide (ASO) tool payloads. anti-TfR1 NANOBODY(R)-siRNA conjugates can induce up to 60% knockdown of the target mRNA transcript in skeletal muscle up to two weeks post a single IV dose in mice and up to 35-40% at four weeks post dose. Furthermore, extending the half-life of the anti-TfR1 NANOBODY(R)-ASO shuttles enhances heart, sciatic nerve, and brain exposure and enables up to 30-60% target knockdown in different CNS cell types. Altogether, these results highlight important features for the development of anti-TfR1 shuttles for the purpose of downregulating target mRNA transcripts in muscle and CNS for a variety of neurologic and neuromuscular indications.

neuroscience↗

bioRxiv2025

Development of conditional-siRNA programmable riboswitch for targeting adverse cardiac remodeling

Heart Failure (HF) remains a global epidemic and a significant healthcare burden, with an unmet need for novel therapies to target the preceding pathological hypertrophy in vulnerable patients. Here we report the development of novel conditional-siRNA (Cond- siRNA) constructs that are selectively activated by disease-specific RNA biomarkers to enable cell-specific inhibition of a target disease-causing RNA. We designed a Cond- siRNA that can be activated by nppa mRNA, upregulated specifically in CMs under pathological stress, to silence the key pro-hypertrophic gene calcineurin by the effector siRNA. In cellular models including neonatal rat ventricular myocyte (NRVM) and rat cardiomyocyte cell-line (H9C2), Cond-siRNA exhibited low baseline activity in the absence of the disease biomarker but achieved targeted calcineurin silencing upon nppa mRNA induction by phenylephrine (PE)-induced stress in a two-dimensional (2D) cell culture system and pressure overload in three-dimensional (3D) heart-on a chip system. NRVM transfection with the Cond-siRNA resulted in a decreased expression of calcineurin mRNA specifically after PE or pressure-overload treatment, but not after vehicle treatment, proving nppa mRNA-specific activation of the effector siRNA against calcineurin. Specificity was confirmed as Cond-siRNA did not significantly silence calcineurin in cardiac fibroblasts and T cells, lacking nppa expression. Reduced calcineurin protein levels and NFATc1 nuclear translocation correlated with decreased NRVM hypertrophy after PE treatment, confirming Cond-siRNAs efficacy. This study offers proof-of-concept for Cond-siRNA as a targeted therapy to mitigate hypertrophic progression, paving the way for novel HF treatments. One sentence summaryConditional-siRNA targeting adverse cardiac remodeling GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/633434v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1b6532borg.highwire.dtl.DTLVardef@10e3836org.highwire.dtl.DTLVardef@8c839eorg.highwire.dtl.DTLVardef@1152883_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2019

Red blood cell-derived extracellular vesicles mediate intercellular communication in ischemic heart failure

Extracellular vesicles (EV) mediate intercellular signaling by transferring their cargo to recipient cells. Red blood cell (RBC)-derived EVs constitute a significant proportion of circulating EVs and have been implicated in regulating immune responses. Here, we describe a transgenic mouse model for fluorescent-based mapping of RBC-EV target cells based on the functional transfer of EV-contained Cre-recombinase to target cells. In a murine model of ischemic heart failure, we detect an increase in RBC-EV-targeted cardiomyocytes in the hearts and microglial cells in the brains. Cells targeted by RBC-EVs present an enrichment of genes implicated in cell proliferation and metabolism pathways compared to non-recombined (non-targeted) cells. Cardiomyocytes targeted by RBC-EVs are more likely to demonstrate cellular markers of DNA synthesis and proliferation, suggesting functional significance of EV-mediated signaling. In conclusion, we leverage our mouse model for mapping of RBC-EV targets in murine ischemic heart failure to demonstrate quantitative and qualitative changes in RBC-EV recipients.

cell biology↗