α-Synuclein and Noradrenergic Modulation of Immune Cells in Parkinson’s Disease Pathogenesis

α-synuclein (α-syn) pathology and loss of noradrenergic neurons in the locus coeruleus (LC) are among the most ubiquitous features of Parkinson’s disease (PD). While noradrenergic dysfunction is associated with non-motor symptoms of PD, preclinical research suggests that the loss of LC norepinephrine (NE), and subsequently its immune modulatory and neuroprotective actions, may exacerbate or even accelerate disease progression. In this review, we discuss the mechanisms by which α-syn pathology and loss of central NE may directly impact brain health by interrupting neurotrophic factor signaling, exacerbating neuroinflammation, and altering regulation of innate and adaptive immune cells

Deposition of microparticles by neutrophils onto inflamed epithelium: a new mechanism to disrupt epithelial intercellular adhesions and promote transepithelial migration

Neutrophil [polymorphonuclear leukocyte (PMN)] transepithelial migration (TEM) is a hallmark of inflammatory mucosal disorders. PMN TEM is associated with epithelial injury; however, mechanisms involved in this process are not well defined. The current work describes a new mechanism whereby deposition of PMN membranederived microparticles (PMNâ MPs) onto intestinal epithelial cells (IECs) during TEM leads to loss of epithelial cadherins, thus promoting epithelial injury and increased PMN recruitment. PMNâ MPs secreted by activated PMNs during TEM displayed a high level of enzymatically activematrixmetalloproteinase 9 (MMPâ 9), and were capable of mediating potent effects on IEC integrity. Isolated PMNâ MPs efficiently bound to IEC monolayers and induced cleavage of desmogleinâ 2 (DSGâ 2) but not Eâ cadherin, leading to disruption of IEC intercellular adhesions. Furthermore, PMNâ MP binding to intestinal epithelium in vitro in transwell assays and in vivo in ligated intestinal loop preparations facilitated increases in PMN TEM. These effects were MMPâ 9 dependent and were reversed in the presence of specific pharmacological inhibitors. Finally, we demonstrated that IEC Dsgâ 2 serves as a barrier for migrating PMNs, and its removal by PMNâ MPâ associated MMPâ 9 facilitates PMNtrafficking across epithelial layers. Our findings thus implicate PMNâ MPs in PMNâ mediated inflammation and epithelial damage, as observed in inflammatory disorders ofmucosal surfaces.â Butinâ Israeli, V., Houser, M.C., Feng, M., Thorp, E. B., Nusrat, A., Parkos, C. A, Sumagin, R. Deposition of microparticles by neutrophils onto inflamed epithelium: anewmechanism to disrupt epithelial intercellular adhesions and promote transepithelialmigration. FASEB J. 30, 4007â 4020 (2016). www.fasebj.orgPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154234/1/fsb2fasebj30120734r.pd

Relationships of gut microbiota, short-chain fatty acids, inflammation, and the gut barrier in Parkinson's disease

Background Previous studies have reported that gut microbiota, permeability, short-chain fatty acids (SCFAs), and inflammation are altered in Parkinson's disease (PD), but how these factors are linked and how they contribute to disease processes and symptoms remains uncertain. This study sought to compare and identify associations among these factors in PD patients and controls to elucidate their interrelations and links to clinical manifestations of PD. Methods Stool and plasma samples and clinical data were collected from 55 PD patients and 56 controls. Levels of stool SCFAs and stool and plasma inflammatory and permeability markers were compared between patients and controls and related to one another and to the gut microbiota. Results Calprotectin was increased and SCFAs decreased in stool in PD in a sex-dependent manner. Inflammatory markers in plasma and stool were neither intercorrelated nor strongly associated with SCFA levels. Age at PD onset was positively correlated with SCFAs and negatively correlated with CXCL8 and IL-1 beta in stool. Fecal zonulin correlated positively with fecal NGAL and negatively with PD motor and non-motor symptoms. Microbiota diversity and composition were linked to levels of SCFAs, inflammatory factors, and zonulin in stool. Certain relationships differed between patients and controls and by sex. Conclusions Intestinal inflammatory responses and reductions in fecal SCFAs occur in PD, are related to the microbiota and to disease onset, and are not reflected in plasma inflammatory profiles. Some of these relationships are distinct in PD and are sex-dependent. This study revealed potential alterations in microbiota-host interactions and links between earlier PD onset and intestinal inflammatory responses and reduced SCFA levels, highlighting candidate molecules and pathways which may contribute to PD pathogenesis and clinical presentation and which warrant further investigation.Peer reviewe

Progranulin Loss Results in Sex-Dependent Dysregulation of the Peripheral and Central Immune System

INTRODUCTION: Progranulin (PGRN) is a secreted glycoprotein, the expression of which is linked to several neurodegenerative diseases. Although its specific function is still unclear, several studies have linked it with lysosomal functions and immune system regulation. Here, we have explored the role of PGRN in peripheral and central immune system homeostasis by investigating the consequences of PGRN deficiency on adaptive and innate immune cell populations. METHODS: First, we used gene co-expression network analysis of published data to test the hypothesis that RESULTS: Male PGRN KO mice exhibited a lower abundance of microglial cells with higher MHC-II expression, increased CD44 expression on monocytes in the brain, and more CNS-associated CD8 DISCUSSION: Our data suggest that PGRN and GPNMB jointly regulate the peripheral and the central immune system in a sex-specific manner; thus, understanding their associated mechanisms could pave the way for developing new neuroprotective strategies to modulate central and peripheral inflammation to lower risk for neurodegenerative diseases and possibly delay or halt progression

Bacterial Butyrate in Parkinson's Disease Is Linked to Epigenetic Changes and Depressive Symptoms

Background The gut microbiome and its metabolites can impact brain health and are altered in Parkinson's disease (PD) patients. It has been recently demonstrated that PD patients have reduced fecal levels of the potent epigenetic modulator butyrate and its bacterial producers. Objectives Here, we investigate whether the changes in the gut microbiome and associated metabolites are related to PD symptoms and epigenetic markers in leucocytes and neurons. Methods Stool, whole blood samples, and clinical data were collected from 55 PD patients and 55 controls. We performed DNA methylation analysis on whole blood samples and analyzed the results in relation to fecal short-chain fatty acid concentrations and microbiota composition. In another cohort, prefrontal cortex neurons were isolated from control and PD brains. We identified genome-wide DNA methylation by targeted bisulfite sequencing. Results We show that lower fecal butyrate and reduced counts of genera Roseburia, Romboutsia, and Prevotella are related to depressive symptoms in PD patients. Genes containing butyrate-associated methylation sites include PD risk genes and significantly overlap with sites epigenetically altered in PD blood leucocytes, predominantly neutrophils, and in brain neurons, relative to controls. Moreover, butyrate-associated methylated-DNA regions in PD overlap with those altered in gastrointestinal (GI), autoimmune, and psychiatric diseases. Conclusions Decreased levels of bacterially produced butyrate are related to epigenetic changes in leucocytes and neurons from PD patients and to the severity of their depressive symptoms. PD shares common butyrate-dependent epigenetic changes with certain GI and psychiatric disorders, which could be relevant for their epidemiological relation. (c) 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder SocietyPeer reviewe

Deposition of microparticles by neutrophils onto inflamed epithelium: a new mechanism to disrupt epithelial intercellular adhesions and promote transepithelial migration

Neutrophil [polymorphonuclear leukocyte (PMN)] transepithelial migration (TEM) is a hallmark of inflammatory mucosal disorders. PMN TEM is associated with epithelial injury; however, mechanisms involved in this process are not well defined. The current work describes a new mechanism whereby deposition of PMN membranederived microparticles (PMNâ MPs) onto intestinal epithelial cells (IECs) during TEM leads to loss of epithelial cadherins, thus promoting epithelial injury and increased PMN recruitment. PMNâ MPs secreted by activated PMNs during TEM displayed a high level of enzymatically activematrixmetalloproteinase 9 (MMPâ 9), and were capable of mediating potent effects on IEC integrity. Isolated PMNâ MPs efficiently bound to IEC monolayers and induced cleavage of desmogleinâ 2 (DSGâ 2) but not Eâ cadherin, leading to disruption of IEC intercellular adhesions. Furthermore, PMNâ MP binding to intestinal epithelium in vitro in transwell assays and in vivo in ligated intestinal loop preparations facilitated increases in PMN TEM. These effects were MMPâ 9 dependent and were reversed in the presence of specific pharmacological inhibitors. Finally, we demonstrated that IEC Dsgâ 2 serves as a barrier for migrating PMNs, and its removal by PMNâ MPâ associated MMPâ 9 facilitates PMNtrafficking across epithelial layers. Our findings thus implicate PMNâ MPs in PMNâ mediated inflammation and epithelial damage, as observed in inflammatory disorders ofmucosal surfaces.â Butinâ Israeli, V., Houser, M.C., Feng, M., Thorp, E. B., Nusrat, A., Parkos, C. A, Sumagin, R. Deposition of microparticles by neutrophils onto inflamed epithelium: anewmechanism to disrupt epithelial intercellular adhesions and promote transepithelialmigration. FASEB J. 30, 4007â 4020 (2016). www.fasebj.or

The impact of heat exposures on biomarkers of AKI and plasma metabolome among agricultural and non-agricultural workers

Background: Agricultural workers are consistently exposed to elevated heat exposures and vulnerable to acute kidney injury. The underlying pathophysiology and detailed molecular mechanisms of AKI among agricultural workers, and the disproportionate burden of HRI and heat stress exposure are not well understood, especially at the level of cellular metabolism. Objective: The aim of this study was to examine the impact of heat exposures on renal biomarkers and on the human metabolome via untargeted high-resolution metabolomics among agricultural and non-agricultural workers. Methods: Blood and urine samples were collected pre- and post-work shift from 63 agricultural workers and 27 non– agricultural workers. We evaluated pre- and post-work shift renal biomarkers and completed untargeted metabolomics using high-resolution mass spectrometry with liquid chromatography. Metabolome-wide association studies (MWAS) models identified the metabolic features differentially expressed between agricultural workers and non-agricultural workers. Results: Median values of pre-shift creatinine and osteopontin (p < 0.05) were higher for agricultural workers than non-agricultural workers. Metabolic pathway enrichment analyses revealed 27 diverse pathways differed between agricultural workers and non-agricultural workers (p < 0.05) including TCA cycle and urea cycle, carbohydrate metabolism, histidine metabolism and evidence for altered microbiome shikimate pathway. Conclusion: This is the first investigation on the metabolic pathways that are affected among agricultural workers who are exposed to heat compared to non-heat exposed workers. This study shows extensive responses of central metabolic systems to heat exposures that impact human health