Biology subjects

Ensink, E.

Publications and source records attributed to Ensink, E..

6 recordsLinked to original sources

bioRxiv2024

Tet2 loss suppress α-synuclein pathology by stimulating ciliogenesis

There are no approved treatments that slow Parkinsons disease (PD) progression and therefore it is important to identify novel pathogenic mechanisms that can be targeted. Loss of the epigenetic marker, Tet2 appears to have some beneficial effects in PD models, but the underlying mechanism of action is not well understood. We performed an unbiased transcriptomic analysis of cortical neurons isolated from patients with PD to identify dysregulated pathways and determine their potential contributions to the disease process. We discovered that genes associated with primary cilia, non-synaptic sensory and signaling organelles, are upregulated in both early and late PD patients. Enhancing ciliogenesis in primary cortical neurons via sonic hedgehog signaling suppressed the accumulation of -synuclein pathology in vitro. Interestingly, deletion of Tet2 in mice also enhanced the expression of primary cilia and sonic hedgehog signaling genes and rescued the accumulation of -synuclein pathology and dopamine neuron degeneration in vivo. Our findings demonstrate the crucial role of Tet2 loss in regulating ciliogenesis and potentially affecting the progression of PD pathology.

neuroscience↗

bioRxiv2024

Gene expression asymmetry in Parkinson's Disease; variation of CCT and BEX gene expression levels are correlated with hemisphere specific severity

Parkinsons Disease (PD) develops unilaterally, which may be related to brain hemispheric differences in gene expression. Here we measured bulk RNA-seq levels in neuronal nuclei obtained from prefrontal cortex postmortem brain samples from males and females with PD and from healthy controls. Left and right hemispheres from each brain were related the side of symptom onset and compared. We employed two a priori approaches; first we identified genes differentially expressed between PD and controls and between left vs right PD brain hemispheres. Second, we examined the presence of, and correlates to, variable asymmetry seen in candidate PD differentially expressed genes. We found large variation among individuals with PD, and PD stratification by gene expression similarity was required for patterns of genetic asymmetry to emerge. For a subset of PD brains, hemispherical variation of CCT and BEX gene levels correlated with the side of PD symptom onset.

neuroscience↗

bioRxiv2021

The glutathione import system satisfies the Staphylococcus aureus nutrient sulfur requirement and promotes interspecies competition.

Sulfur is an indispensable element for proliferation of bacterial pathogens. Prior studies indicated that the human pathogen, Staphylococcus aureus utilizes glutathione (GSH) as a source of nutrient sulfur; however, mechanisms of GSH acquisition are not defined. Here, we identify a previously uncharacterized five-gene locus comprising a putative ABC-transporter and {gamma}-glutamyl transpeptidase (ggt) that promotes S. aureus proliferation in medium supplemented with either reduced or oxidized GSH (GSSG) as the sole source of nutrient sulfur. Based on these phenotypes, we name this transporter the Glutathione import system (GisABCD). We confirm that Ggt is capable of cleaving GSH and GSSG {gamma}-bonds and that this process is required for their use as nutrient sulfur sources. Additionally, we find that the enzyme is cell associated. Bioinformatic analyses reveal that only Staphylococcus species closely related to S. aureus encode GisABCD-Ggt homologues. Homologues are not detected in Staphylococcus epidermidis. Consequently, we establish that GisABCD-Ggt provides a competitive advantage for S. aureus over S. epidermidis in a GSH-dependent manner. Overall, this study describes the discovery of a nutrient sulfur acquisition system in S. aureus that targets GSH and promotes competition against other staphylococci commonly associated with the human microbiota.

microbiology↗

bioRxiv2020

Gut microbiome dysbiosis is associated with elevated toxic bile acids in Parkinson's disease

The gut microbiome can impact brain health and is altered in Parkinsons disease (PD) patients. Here, we investigate changes in the functional microbiome in the appendix of PD patients relative to controls by metatranscriptomic analysis. We find microbial dysbiosis affecting lipid metabolism, particularly an upregulation of bacteria responsible for secondary bile acid synthesis. Proteomic and transcript analysis corroborates a disruption in cholesterol homeostasis and lipid catabolism. Bile acid analysis reveals an increase in microbially-derived, toxic secondary bile acids. Synucleinopathy in mice induces similar microbiome alterations to those of PD patients. The mouse model of synucleinopathy has elevated DCA and LCA. An analysis of blood markers shows evidence of biliary abnormalities early in PD, including elevated alkaline phosphatase and bilirubin. Increased bilirubin levels are also evident before PD diagnosis. In sum, microbially-derived toxic bile acids are heightened in PD and biliary changes may even precede the onset of overt motor symptoms.

neuroscience↗

bioRxiv2019

Epigenetic contributions to hemisphere asymmetry in healthy brain, aging, and Parkinson’s disease

Hemispheric asymmetry in neuronal processes is a fundamental feature of the human brain and drives symptom lateralization in Parkinsons disease (PD), but its molecular determinants are unknown. Here, we determine epigenetic differences involved in hemispheric asymmetry in the healthy and the PD brain. Neurons of the healthy brain exhibit numerous hemispheric differences in DNA methylation, which affect genes implicated in neurodegenerative diseases. In PD patients, hemispheric asymmetry in DNA methylation is even greater and involves many PD risk genes. The lateralization of clinical PD symptoms involves epigenetic, transcriptional, and proteomic differences across hemispheres that affect neurodevelopment, immune activation, and synaptic transmission. During aging, healthy neurons show a progressive loss of hemispheric asymmetry in the epigenome, which is amplified in PD. For PD patients, a long disease course is associated with greater hemispheric asymmetry in neuronal epigenomes than a short disease course. Hemispheric differences in epigenetic gene regulation are prevalent in neurons and may affect the progression and symptoms of PD.

neuroscience↗

bioRxiv2019

Epigenomic analysis of Parkinson’s disease neurons identifies Tet2 loss as neuroprotective

PD pathogenesis may involve the epigenetic control of enhancers that modify neuronal functions. Here, we comprehensively profile DNA methylation at enhancers, genome-wide, in neurons of 57 PD patients and 48 control individuals. We found a widespread increase in cytosine modifications at enhancers in PD neurons, which is partly explained by elevated hydroxymethylation levels. Epigenetic dysregulation of enhancers in PD converge on transcriptional abnormalities affecting neuronal signaling and immune activation pathways. In particular, PD patients exhibit an epigenetic and transcriptional upregulation of TET2, a master-regulator of cytosine modification status. TET2 inactivation in a neuronal cell line results in cytosine modification changes that are reciprocal to those observed in PD neurons. Furthermore, Tet2 inactivation in mice fully prevents dopaminergic neuronal loss in the substantia nigra induced by prior inflammation. Tet2 loss in mice also attenuates transcriptional immune responses to an inflammatory trigger. Thus, widespread epigenetic dysregulation of enhancers in PD neurons may, in part, be mediated by increased TET2 expression. Decreased Tet2 activity is neuroprotective, in vivo, and may be a novel therapeutic target for PD.

neuroscience↗