Biology subjects

Nobles, A.

Publications and source records attributed to Nobles, A..

3 recordsLinked to original sources

bioRxiv2025

Lipid lowering alone fails to limit atherosclerosis progression and neutrophilic inflammation in middle-aged mice

While cholesterol lowering remains the cornerstone therapy for atherosclerosis and prevention of major adverse cardiovascular events, 33-50% of individuals on lipid-lowering therapy continue to exhibit elevated inflammation. Middle age (MA) represents a critical window for disease acceleration, underscoring a need to better understand non-resolving inflammation in this time frame. We rendered young (2 months) and MA mice (10 months) hypercholesterolemic with an AAV8-PCSK9 virus and fed a western diet (WD). Following 20 weeks on a WD, mice were switched to chow for 6 weeks to mimic lipid-lowering therapy. We found that MA atherosclerotic mice had increased plaque necrosis with increased circulating and bone marrow PMN compared to young mice. Upon lipid lowering, unlike in young mice, MA mice had increased necrosis, and reduced remodeling as well as increased circulating white blood cells and bone marrow hematopoietic stem cell progenitors (HSPCs). Circulating neutrophils correlated with necrosis in MA mice whereas young mice exhibited no correlation. Lipid lowered MA atherosclerotic mice had bone marrow HSPCs and neutrophils that exhibited a more activated phenotype relative to young. Elevated neutrophil-endothelial contacts were observed in the hippocampal vasculature of MA lipid lowered mice. While lipid lowering restrains atheroprogression in young, it is inadequate in MA, failing to reduce systemic inflammation and indicating the need for complementary therapies during this time frame.

immunology↗

bioRxiv2024

Rab27b promotes lysosomal function and alpha-synuclein clearance in neurons

Alpha-synuclein (syn) is the key pathogenic protein implicated in synucleinopathies including Parkinsons Disease (PD) and Dementia with Lewy Bodies (DLB). In these diseases, syn is thought to spread between cells where it accumulates and induces pathology; however, mechanisms that drive its propagation or aggregation are poorly understood. We have previously reported that the small GTPase Rab27b is elevated in human PD and DLB and that it can mediate the autophagic clearance and toxicity of syn in a paracrine syn cell culture neuronal model. Here, we expanded our previous work and further characterized a role for Rab27b in neuronal lysosomal processing and syn clearance. We found that Rab27b KD in this syn inducible neuronal model resulted in lysosomal dysfunction and increased syn levels in lysosomes. Similar lysosomal proteolytic defects and enzymatic dysfunction were observed in both primary neuronal cultures and brain lysates from Rab27b knockout (KO) mice. Syn aggregation was exacerbated in Rab27b KO neurons upon treatment with syn preformed fibrils. We found no changes in lysosomal counts or lysosomal pH in either model, but we did identify defects in acidic vesicle trafficking in Rab27b KO primary neurons which may drive lysosomal dysfunction and promote syn aggregation. Rab27b OE enhanced lysosomal activity and reduced insoluble syn accumulation. Finally we found elevated Rab27b levels in human postmortem incidental Lewy Body Disease (iLBD) subjects relative to healthy controls. These data suggest a role for Rab27b in neuronal lysosomal activity and identify it as a potential therapeutic target in synucleinopathies.

neuroscience↗

bioRxiv2022

Skeletal Muscle Proteostasis Promotes Central Nervous System Rejuvenation and Reduces Neuroinflammation during Aging and Neurodegenerative Disease

Skeletal muscle has recently arisen as a novel regulator of Central Nervous System (CNS) function and aging, secreting bioactive molecules known as myokines with metabolism-modifying functions in targeted tissues, including the CNS. Here we report the generation of a novel transgenic mouse with enhanced skeletal muscle lysosomal and mitochondrial function via targeted overexpression of Transcription Factor E-B (TFEB). We have discovered that the resulting geroprotective effects in skeletal muscle reduce neuroinflammation and the accumulation of tau-associated pathological hallmarks in a mouse model of tau pathology. Muscle-specific TFEB overexpression also significantly ameliorates proteotoxicity, reduces neuroinflammation and promotes transcriptional remodeling of the aged CNS, preserving cognition and memory in aged mice. Our results implicate the maintenance of skeletal muscle function throughout aging to direct regulation of CNS health and disease, and suggest that skeletal-muscle originating factors may act as novel therapeutic targets against age-associated neurodegenerative disorders.

neuroscience↗