Biology subjects

Sardi, P.

Publications and source records attributed to Sardi, P..

5 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

AAV gene therapy for GBA-PD and Gaucher Disease

Mutations in GBA1, the gene encoding glucocerebrosidase (GCase), are the most common risk factor for Parkinsons Disease (PD). GBA-PD patients are a genetic subpopulation of PD carrying heterozygous mutations in GBA1. Additionally, bi-allelic mutations in GBA1 cause Gaucher Disease (GD), a lysosomal storage disorder. Loss of GCase activity, a lysosomal enzyme leads to the accumulation of lipid substrates, disrupting lipid homeostasis and promoting cellular toxicity. Here, we report an AAV-mediated GBA1 replacement strategy to treat GD and GBA-PD by a one-time infusion via intravenous (GD Type 1) or intra-CSF (GBA-PD) route of administration. We engineered human GCase to be readily secretable to facilitate broad cross-correction. We developed CBE (conduritol {beta}-epoxide) induced lipid accumulation models to assess efficacy in mice and non-human primates (NHPs) to assess efficacy of our engineered constructs. Based on data across species, across different routes of administration, we nominated AAV.GMU01 SS3-GBA1 as our lead candidate. SS3-GBA1 is robustly secreted, cross-corrected across tissues and promotes lipid clearance. By comparing human GCase levels in AAV-treated NHP brains to healthy human donor brains, we demonstrate that AAV.GMU01 SS3-GBA1 replenishes the GCase deficit seen in GBA-PD patients, thus, restoring GCase to near-physiological levels Importantly, AAV.GMU01 SS3-GBA1 is well-tolerated with no adverse findings. Collectively, we establish a therapeutic strategy for the treatment of Gaucher Disease and GBA-PD with a single gene therapy product. One Sentence SummaryA novel gene therapy strategy for GBA1-PD and Gaucher disease with an engineered payload that robustly cross-corrects enhancing therapeutic footprint

neuroscience↗

bioRxiv2021

Single Nuclei Sequencing of Human Putamen Oligodendrocytes Reveals Altered Heterogeneity and Disease-Associated Changes in Parkinson's Disease and Multiple System Atrophy

The role of oligodendrocytes in neurodegenerative diseases remains incompletely understood and largely unexplored at the single cell level. We profiled 87,086 single nuclei from human brain putamen region for healthy control, Parkinsons Disease (PD), and Multiple System Atrophy (MSA). Oligodendrocyte lineage cells were the dominant cell-type in the putamen with oligodendrocyte subpopulations clustered by transcriptomic variation found to exhibit diverse functional enrichment patterns, and this oligodendrocyte heterogeneity was altered in a disease-specific way. Among profiled oligodendrocyte subpopulations, differences in expression of SNCA, HAPLN2, MAPT, APP, and OPALIN were observed for PD and MSA compared with healthy controls. Intriguingly, greater activation of unfolded protein response pathway gene expression was observed in PD nuclei versus MSA. Using network analysis, we then identified specific PD- and MSA-correlated gene co-expression modules enriched with disease relevant pathways; the PD-correlated module was significantly enriched for Parkinsons Disease GWAS loci (p = 0.01046). Our analysis provides a broader understanding of oligodendrocyte heterogeneity and reveals distinctive oligodendrocyte pathological alterations associated with PD and MSA which may suggest potential novel therapeutic targets and new strategies for disease modification.

genomics↗

bioRxiv2020

Insulin-like growth factor 2 (IGF2) protects against Huntington's disease through the extracellular disposal of protein aggregates

Impaired neuronal proteostasis is a salient feature of many neurodegenerative diseases, highlighting alterations in the function of the endoplasmic reticulum (ER). We previously reported that targeting the transcription factor XBP1, a key mediator of the ER stress response, delays disease progression and reduces protein aggregation in various models of neurodegeneration. To identify disease-modifier genes that may explain the neuroprotective effects of XBP1 deficiency, we performed gene expression profiling of brain cortex and striatum of these animals and uncovered insulin-like growth factor 2 (Igf2) as the major upregulated gene. Here we studied the impact of IGF2 signaling on protein aggregation in models of Huntingtons disease (HD) as proof-of-concept. Cell culture studies revealed that IGF2 treatment decreases the load of intracellular aggregates of mutant huntingtin and a polyglutamine peptide. These results were validated using induced pluripotent stem cells (iPSC)-derived medium spiny neurons from HD patients. The reduction in the levels of mutant huntingtin was associated with a decrease in the half-life of the intracellular protein. The decrease in the levels of abnormal protein aggregation triggered by IGF2 were independent of the activity of autophagy and the proteasome pathways, the two main routes for mutant huntingtin clearance. Conversely, IGF2 signaling enhanced the secretion of soluble mutant huntingtin species through exosomes and microvesicles involving changes in actin dynamics. Administration of IGF2 into the brain of HD mice using gene therapy led to a significant decrease in the levels of mutant huntingtin in three different animal models. Moreover, analysis of human post-mortem brain tissue, and blood samples from HD patients showed a reduction of IGF2 level. This study identifies IGF2 as a relevant factor deregulated in HD, operating as a disease modifier that buffers the accumulation of abnormal protein aggregates. One sentence summaryIGF2 reduces the load of intracellular protein aggregates through the extracellular disposal of the mutant protein.

neuroscience↗

bioRxiv2020

Control of mammalian brain aging by the unfolded protein response (UPR)

Aging is the major risk factor for the development of dementia and neurodegenerative disorders, and the aging brain manifests severe deficits in buffering capacity by the proteostasis network. Accordingly, we investigated the significance of the unfolded protein response (UPR), a major signaling pathway that copes with endoplasmic reticulum (ER) stress, to normal mammalian brain aging. Genetic disruption of ER stress sensor IRE1 accelerated cognitive and motor dysfunction during aging. Exogenous bolstering of the UPR by overexpressing an active form of the transcription factor XBP1 restored synaptic and cognitive function in addition to reducing cell senescence. Remarkably, proteomic profiling of hippocampal tissue indicated that XBP1s expression corrected age-related alterations in synaptic function. Collectively, our data demonstrate that strategies to manipulate the UPR sustain healthy brain aging. One Sentence SummaryThe IRE1/XBP1 pathway dictates when and how brain function declines during aging.

neuroscience↗