Biology subjects

Bellotto, M.

Publications and source records attributed to Bellotto, M..

3 recordsLinked to original sources

bioRxiv2026

Differential Effects of Neutral Sphingomyelinase and Serine Palmitoyltransferase Inhibitors on Alzheimer's-Like Neuropathology.

Alzheimer's disease (AD) involves progressive neurodegeneration, amyloid-{beta} (A{beta}) pathology and chronic neuroinflammation. Elevated ceramides, generated via neutral sphingomyelinase (nSMase)-mediated sphingomyelin hydrolysis or serine palmitoyltransferase (SPT)-driven de novo synthesis, amplify these processes. Here, we performed a direct comparison of pharmacological inhibition of these pathways in the PDAPP-J20 transgenic mouse model and in fibrillized A{beta}1-42-challenged BV-2 murine microglial cell line. Eight-month-old PDAPP-J20 female mice received intraperitoneal GW4869 (nSMase inhibitor, 1.25 mg/kg) or myriocin (SPT inhibitor, 0.3 mg/kg) three times weekly for 3 weeks. Neutral SMase inhibition restored spatial learning in the Barnes maze, reduced hippocampal neuronal loss and layer atrophy, decreased amyloid plaque burden, and attenuated microglial activation (Iba1 morphology and peri-plaque reactivity). In contrast, SPT inhibition worsened thigmotaxis, failed to improve cognition, and increased plaque load. In vitro, nSMase blockade (GW4869 and cambinol) suppressed A{beta}-induced NF{kappa}B p65 nuclear translocation, blunted TNF- expression, and reduced intracellular A{beta} accumulation in microglia, suggesting enhanced endolysosomal degradation. SPT inhibition lacked these anti-inflammatory and clearance-promoting effects. These results identify nSMase as a critical node linking ceramide metabolism, microglial dysfunction, and amyloid progression in AD. Targeted nSMase inhibition offers a promising molecular strategy to interrupt neuroinflammation and restore neuronal homeostasis, while broad SPT blockade appears counterproductive. Pathway-selective modulation of ceramide signaling may open new therapeutic avenues for AD.

neuroscience↗

bioRxiv2024

A novel class of allosteric glucosylceramidase beta 1 correctors that reduce cellular stress and enhance lysosomal function

Mutations in glucosylceramidase beta 1 (GCase) disrupt the proteins conformational maturation in the endoplasmic reticulum (ER) and hinder its transport to the lysosome. The intralysosomal accumulation of glucocerebrosides, which are substrates of the GCase enzyme, impairs lysosomal function and is linked to Gaucher disease (GD). GCase mutations also increase the risk of Parkinsons disease (PD) and Dementia with Lewy Bodies. We used Site-directed Enzyme Enhancement Therapy (SEE-Tx(R)) technology to design two structurally targeted allosteric regulators (STARs) of GCase. Administration of GT-02287 and GT-02329 to cultured GD patient-derived primary human fibroblasts enhances folding and protects the two most common disease-causing GCase variants, GCaseAsn370Ser and GCaseLeu444Pro, from proteasomal degradation. Mechanistically, these treatments facilitate the lysosomal delivery of enzymatically active forms of mutant GCase, leading to improved lysosomal function and reduced cellular stress in GD patient-derived fibroblasts. The findings suggest that the allosteric pharmacologic regulators GT-02287 and GT-02329 hold promise for further development as potential therapeutic agents for GCase-related disorders, including GD, PD and Dementia with Lewy Bodies.

cell biology↗

bioRxiv2024

Pharmacological GCase Activity Enhancement Inhibits Tau Accumulation

A slow decline in the autophagy-lysosomal pathway is a hallmark of the normal aging brain. Yet, an acceleration of this cellular function may propel neurodegenerative events. In fact, mutations in genes associated with the autophagy-lysosomal pathway can lead to Parkinsons disease. Also, amyloidogenic protein deposition is observed in lysosomal storage disorders, which are caused by genetic mutations representing risk factors for Parkinsons disease. For example, Gauchers disease GBA1 mutations leading to defects in lysosomal sphingolipid metabolism cause -synuclein accumulation. We observed that increased lysosomal Tau accumulation is found in human dermal fibroblasts engineered for inducible Tau expression. Inhibition of the GBA1 product GCase augmented Tau-dependent lysosomal stress and Tau accumulation. Here, we show increased Tau seed-induced Tau accumulation in Gauchers fibroblasts carrying GBA1 mutations when compared to normal fibroblasts. Pharmacological enhancement of GCase reversed this effect, notably, also in normal fibroblasts. This suggests that boosting GCase activity may represent a therapeutic strategy to slow down aging-dependent lysosomal deficits and brain protein deposition.

cell biology↗