Electrophysiological and Morphological Maturation of Murine Fetal Cardiomyocytes During Electrical Stimulation In Vitro
JOURNAL OF CARDIOVASCULAR PHARMACOLOGY AND THERAPEUTICS
Authors: Baumgartner, Sven; Halbach, Marcel; Krausgrill, Benjamin; Maass, Martina; Srinivasan, Sureshkumar Perumal; Sahito, Raja Ghazanfar Ali; Peinkofer, Gabriel; Nguemo, Filomain; Mueller-Ehmsen, Jochen; Hescheler, Juergen
Abstract
The aim of this study was to investigate whether continuous electrical stimulation affects electrophysiological properties and cell morphology of fetal cardiomyocytes (FCMs) in culture. Fetal cardiomyocytes at day 14.5 post coitum were harvested from murine hearts and electrically stimulated for 6 days in culture using a custom-made stimulation chamber. Subsequently, action potentials of FCM were recorded with glass microelectrodes. Immunostainings of -Actinin, connexin 43, and vinculin were performed. Expression of ion channel subunits Kcnd2, Slc8a1, Cacna1, Kcnh2, and Kcnb1 was analyzed by quantitative reverse-transcriptase polymerase chain reaction. Action potential duration to 50% and 90% repolarization (APD(50) and APD(90)) of electrically stimulated FCMs were significantly decreased when compared to nonstimulated control FCM. Alignment of cells was significantly higher in stimulated FCM when compared to control FCM. The expression of connexin 43 was significantly increased in stimulated FCM when compared to control FCM. The ratio between cell length and cell width of the stimulated FCM was significantly higher than in control FCM. Kcnh2 and Kcnd2 were upregulated in stimulated FCM when compared to control FCM. Expression of Slc8a1, Cacna1c, and Kcnb1 was not different in stimulated and control FCMs. The decrease in APD(50) observed after electrical stimulation of FCM in vitro corresponds to the electrophysiological maturation of FCM in vivo. Expression levels of ion channels suggest that some important but not all aspects of the complex process of electrophysiological maturation are promoted by electrical stimulation. Parallel alignment, increased connexin 43 expression, and elongation of FCM are signs of a morphological maturation induced by electrical stimulation.
Longitudinal Epigenome-Wide Methylation Study of Cognitive Decline and Motor Progression in Parkinson's Disease
JOURNAL OF PARKINSONS DISEASE
Authors: Chuang, Yu-Hsuan; Lu, Ake T.; Paul, Kimberly C.; Folle, Aline D.; Bronstein, Jeff M.; Bordelon, Yvette; Horvath, Steve; Ritz, Beate
Abstract
Background: DNA methylation studies in Parkinson's disease (PD) thus far have focused on disease susceptibility but not progression. Objective: In this epigenome-wide association study (EWAS), we aim to identify methylation markers associated with faster cognitive decline or motor progression in PD. Methods: We included 232 PD patients from the Parkinson's Environment and Gene follow-up study who provided blood samples at enrolment. Information on cognitive and motor function was collected using the Mini-Mental State Examination (MMSE) and Unified Parkinson's Disease Rating Scale (UPDRS). For EWAS analyses, we used a robust measure of correlation: biweight midcorrelations, t-tests, and Cox proportional hazard models. We also conducted weighted correlation network analysis (WGCNA) to identify CpG modules associated with cognitive decline or motor progression in PD. Results: Among 197 individuals of European ancestry, with our EWAS approach we identified 7 genome-wide significant CpGs associated with a MMSE 4-point decline and 8 CpGs associated with faster motor progression (i.e., rate of UPDRS increase >= 5-point/year). The most interesting CpGs for cognitive decline include cg17445913 in KCNB1 (cor = 0.36, p = 6.85 x 10(-7)) and cg02920897 in DLEU2 (cor = 0.34, p = 3.23 x 10(-6)), while for motor progression it was cg01754178 in PTPRN2 (cor = -0.34, p = 2.07 x 10(-6)). In WGCNA, motor progression related modules were enriched for genes related to neuronal synaptic functions, Wnt signaling pathway, and mitochondrial apoptosis. Conclusions: Our study provides the first epigenetic evidence that differential methylation in genes previously identified as being associated with cognitive impairment, neuronal synaptic function, Wnt signaling pathway, and mitochondrial apoptosis is associated with cognitive and motor progression in PD.