Biology subjects

Menees, K. B.

Publications and source records attributed to Menees, K. B..

5 recordsLinked to original sources

bioRxiv2024

RGS10 Attenuates Systemic Immune Dysregulation Induced by Chronic Inflammatory Stress

Regulator of G-protein signaling 10 (RGS10), a key homeostatic regulator of immune cells, has been implicated in multiple diseases associated with aging and chronic inflammation including Parkinsons Disease (PD). Interestingly, subjects with idiopathic PD display reduced levels of RGS10 in subsets of peripheral immune cells. Additionally, individuals with PD have been shown to have increased activated peripheral immune cells in cerebral spinal fluid (CSF) compared to age-matched healthy controls. However, it is unknown whether CSF-resident peripheral immune cells in individuals with PD also exhibit decreased levels of RGS10. Therefore, we performed an analysis of RGS10 levels in the proteomic database of the CSF from the Michael J. Fox Foundation Parkinsons Progression Markers Initiative (PPMI) study. We found that RGS10 levels are decreased in the CSF of individuals with PD compared to healthy controls and prodromal individuals. Moreover, we find that RGS10 levels decrease with age but not PD progression and that males have less RGS10 than females in PD. Importantly, studies have established an association between chronic systemic inflammation (CSI) and neurodegenerative diseases, such as PD, and known sources of CSI have been identified as risk factors for developing PD; however, the role of peripheral immune cell dysregulation in this process has been underexplored. As RGS10 levels are decreased in the CSF and circulating peripheral immune cells of individuals with PD, we hypothesized that RGS10 regulates peripheral immune cell responses to CSI prior to the onset of neurodegeneration. To test this, we induced CSI for 6 weeks in C57BL6/J mice and RGS10 KO mice to assess circulating and CNS-associated peripheral immune cell responses. We found that RGS10 deficiency synergizes with CSI to induce a bias for inflammatory and cytotoxic cell populations, a reduction in antigen presentation in peripheral blood immune cells, as well as in and around the brain that is most notable in males. These results highlight RGS10 as an important regulator of the systemic immune response to CSI and implicate RGS10 as a potential contributor to the development of immune dysregulation in PD.

immunology↗

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

Peripheral Blood Immune Cells from Individuals with Parkinson's Disease or Inflammatory Bowel Disease Share Deficits in Iron Storage and Transport that are Modulated by Non-Steroidal Anti-Inflammatory Drugs

Parkinsons Disease (PD) is a multisystem disorder in which dysregulated neuroimmune crosstalk and inflammatory relay via the gut-blood-brain axis have been implicated in PD pathogenesis. Although alterations in circulating inflammatory cytokines and reactive oxygen species (ROS) have been associated with PD, no biomarkers have been identified that predict clinical progression or disease outcome. Gastrointestinal (GI) dysfunction, which involves perturbation of the underlying immune system, is an early and often-overlooked symptom that affects up to 80% of individuals living with PD. Interestingly, 50-70% of individuals with inflammatory bowel disease (IBD), a GI condition that has been epidemiologically linked to PD, display chronic illness-induced anemia -- which drives toxic accumulation of iron in the gut. Ferroptotic (or iron loaded) cells have small and dysmorphic mitochondria--suggesting that mitochondrial dysfunction is a consequence of iron accumulation. In pro-inflammatory environments, iron accumulates in immune cells, suggesting a possible connection and/or synergy between iron dysregulation and immune cell dysfunction. Peripheral blood mononuclear cells (PBMCs) recapitulate certain PD-associated neuropathological and inflammatory signatures and can act as communicating messengers in the gut-brain axis. Additionally, this communication can be modulated by several environmental factors; specifically, our data further support existing literature demonstrating a role for non-steroidal anti-inflammatory drugs (NSAIDs) in modulating immune transcriptional states in inflamed individuals. A mechanism linking chronic gut inflammation to iron dysregulation and mitochondrial function within peripheral immune cells has yet to be identified in conferring risk for PD. To that end, we isolated PBMCs and simultaneously evaluated their directed transcriptome and bioenergetic status, to investigate if iron dysregulation and mitochondrial sensitization are linked in individuals living with PD or IBD because of chronic underlying remittent immune activation. We have identified shared features of peripheral inflammation and immunometabolism in individuals living with IBD or PD that may contribute to the epidemiological association reported between IBD and risk for PD.

neuroscience↗

bioRxiv2024

Alzheimer's disease-associated protective variant Plcg2-P522R modulates peripheral macrophage function in a sex-dimorphic manner and confers functional advantage in female mice

Genome-wide association studies have identified a protective mutation in the phospholipase C gamma 2 (PLCG2) gene which confers protection against Alzheimers disease (AD)-associated cognitive decline. Therefore, PLCG2, which is primarily expressed in immune cells, has become a target of interest for potential therapeutic intervention. The protective allele, known as P522R, has been shown to be hyper-morphic in microglia, increasing phagocytosis of amyloid-beta (A{beta}), and increasing the release of inflammatory cytokines. However, the effect of this protective mutation on peripheral tissue-resident macrophages, and the extent to which sex modifies this effect, has yet to be assessed. Herein, we show that peripheral macrophages carrying the P522R mutation do indeed show functional differences compared to their wild-type (WT) counterparts, however, these alterations occur in a sex-dependent manner. In macrophages from females, the P522R mutation increases lysosomal protease activity, cytokine secretion, and gene expression associated with cytokine secretion and apoptosis. In contrast, in macrophages from males, the mutation causes decreased phagocytosis and lysosomal protease activity, modest increases in cytokine secretion, and induction of gene expression associated with negative regulation of the immune response. Taken together, these results suggest that the mutation may be conferring different effects dependent on sex and cell type, and highlight the importance of considering sex as a biological variable when assessing the effects of genetic variants and implications for potential immune system-targeted therapies.

neuroscience↗

bioRxiv2024

High-plex Digital Spatial Profiling Identifies Subregion-Dependent Directed Proteome Changes Across Multiple Variants of Dementia

Frontotemporal lobar degeneration (FTLD) is the leading cause of dementia in patients under the age of 65. Even in a single anatomical region, there is variance within pathological protein deposition as a result of FTLD. This spectrum of pathology leads to difficulty in identification of the disease during its progression and consequential varied post mortem clinicopathological diagnoses. NanoString GeoMx Digital Spatial Profiling (DSP) is a novel method that leverages the ability to spatially multiplex protein biomarkers of interest. We utilized NanoString DSP to investigate the proteome geography at two levels of the cortex and the subcortical white matter in patients with various types of dementia (Alzheimers disease, FTLD-c9ALS, FTLD-17, FTLD-TDP, FTLD-GRN; n=6 per syndrome) and neurologically healthy controls (NHC). Analysis of 75 different protein biomarkers of interest revealed both a disease and cortical subregion specific biomarker profile. Layers II-V of the cortex from diseased individuals displayed the greatest protein dysregulation as compared to NHC. Additionally, out of all disease groups within cortical layer 1, II-V and white matter, the FTLD-17 group had the most significant protein dysregulation as compared to NHC--specifically associated with immune cell pathways. Traditional biomarkers of dementia, such as various phosphorylated tau proteins and amyloid-{beta} 42 displayed dysregulation, however our data suggest spatial enrichment in distinct to cortical sublayers. In conclusion, we observed that depending on the variant of disease, specific protein deposits either span multiple levels of cortical geography or only a single layer. Thus, the specific localization of these deposits could potentially be used to elucidate region-specific pathologic biomarkers unique to individual variants of dementia.

neuroscience↗