Biology subjects

McFarland, N. R.

Publications and source records attributed to McFarland, N. R..

3 recordsLinked to original sources

bioRxiv2025

Single-cell multiomics identifies both shared and unique features of immune dysfunction in the colon, plasma and stool from individuals diagnosed with Parkinson's disease or inflammatory bowel disease

Parkinsons disease (PD) is the fastest growing neurodegenerative disease in the world1. Gastrointestinal (GI) dysfunction can occur decades before motor impairments and in up to 80% of individuals living with PD2,3,4. We investigated peripheral relationships that may underlie mechanisms along the gut-blood axis that contribute to PD pathogenesis. Single-cell multiomic spatial molecular imaging (SMI) of colonic tissue localized inflammatory injury within epithelial cells that appear to be associated with iron mishandling in both inflammatory bowel disease (IBD) and PD biosamples. We found that both the single-cell SMI of RNA and protein revealed parallel cross-modal dysregulation in the gut epithelium, in both IBD and PD biosamples. These data are accompanied by plasma (PD) and stool (IBD) protein depletion of CCL22. Our findings suggest iron mishandling along the gut barrier likely contributes to systemic inflammation, which may be the catalyst that primes circulating immune cells to body-first PD pathogenesis.

neuroscience↗

bioRxiv2024

MHCII deletion in mouse myeloid cells alters T-cell subset frequencies and inflammatory responses to alpha-synuclein pathology and epigenetic analysis of human monocytes reveals genotype- as well as disease-dependent differentially accessible chromatin regions in the HLA locus

Major histocompatibility complex class II (MHCII) molecules are antigen presentation proteins and increased in post-mortem Parkinsons disease (PD) brain. Attempts to decrease MHCII expression have led to neuroprotection in PD mouse models. Our group reported that a SNP at rs3129882 in the MHCII gene Human leukocyte Antigen (HLA) DRA is associated with increased MHCII transcripts and surface protein and increased risk for late-onset idiopathic PD. We therefore hypothesized that decreased MHCII may mitigate dopaminergic degeneration. During an ongoing -synuclein lesion, mice with MHCII reduction in systemic and brain innate immune cells (LysMCre+I-Abfl/fl or CRE+) displayed brain T cell repertoire shifts and greater preservation of the dopaminergic phenotype in nigrostriatal terminals. Next, we investigated a human cohort to characterize the immunophenotype of subjects with and without the high-risk GG genotype at the rs3129882 SNP. We confirmed that the high-risk GG genotype is associated with peripheral changes in MHCII inducibility, frequency of CD4+ T cells, and differentially accessible chromatin regions within the MHCII locus. Although our mouse studies indicate that myeloid MHCII reduction coinciding with an intact adaptive immune system is insufficient to fully protect dopamine neurons from -synuclein-induced degeneration, our data are consistent with the overwhelming evidence implicating antigen presentation in PD pathophysiology.

immunology↗

bioRxiv2024

A comparative analysis of Parkinson's disease and inflammatory bowel disease gut microbiomes highlights shared depletions in key butyrate-producing bacteria

Epidemiological studies reveal that a diagnosis of inflammatory bowel disease (IBD) is associated with an increased risk of developing Parkinsons disease (PD). The presence of gut dysbiosis has been documented in both PD and IBD patients, however it is currently unknown how alterations in the gut microbiome may contribute to the epidemiological link between both diseases. To identify shared and distinct features of the PD and IBD microbiome, we performed the first joint analysis of 54 PD, 26 IBD, and 16 healthy control gut metagenomes recruited from clinics at the University of Florida, and directly compared the gut microbiomes from PD and IBD persons. Larger, publicly available PD and IBD metagenomic datasets were also analyzed to validate and extend our findings. Depletions in short-chain fatty acid (SCFA) producing bacteria, including Roseburia intestinalis, Faecalibacterium prausnitzii, Anaerostipes hadrus, and Eubacterium rectale, as well as depletions in SCFA synthesis pathways, were demonstrated across PD and IBD datasets. We posit that direct comparison of PD and IBD gut microbiomes will be important in identifying features within the IBD gut which may be associated with PD. The data revealed a consistent depletion in SCFA-producing bacteria across both PD and IBD, suggesting that loss of these microbes may influence the pathophysiology of both disease states.

neuroscience↗