Fibroblast mitochondria in idiopathic Parkinson’s disease display morphological changes and enhanced resistance to depolarization

in Scientific Reports (2020)

Mitochondrial dysfunction is a hallmark in idiopathic Parkinson’s disease (IPD). Here, we established screenable phenotypes of mitochondrial morphology and function in primary fibroblasts derived from ... [more ▼]

Mitochondrial dysfunction is a hallmark in idiopathic Parkinson’s disease (IPD). Here, we established screenable phenotypes of mitochondrial morphology and function in primary fibroblasts derived from patients with IPD. Upper arm punch skin biopsy was performed in 41 patients with mid-stage IPD and 21 age-matched healthy controls. At the single-cell level, the basal mitochondrial membrane potential (Ψm) was higher in patients with IPD than in controls. Similarly, under carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) stress, the remaining Ψm was increased in patients with IPD. Analysis of mitochondrial morphometric parameters revealed significantly decreased mitochondrial connectivity in patients with IPD, with 9 of 14 morphometric mitochondrial parameters differing from those in controls. Significant morphometric mitochondrial changes included the node degree, mean volume, skeleton size, perimeter, form factor, node count, erosion body count, endpoints, and mitochondria count (all P-values < 0.05). These functional data reveal that resistance to depolarization was increased by treatment with the protonophore FCCP in patients with IPD, whereas morphometric data revealed decreased mitochondrial connectivity and increased mitochondrial fragmentation. [less ▲]

Enteric neurons from Parkinson's disease patients display ex vivo aberrations in mitochondrial structure.

in Scientific reports (2016), 6

Based on autopsy material mitochondrial dysfunction has been proposed being part of the pathophysiological cascade of Parkinson's disease (PD). However, in living patients, evidence for such dysfunction ... [more ▼]

Based on autopsy material mitochondrial dysfunction has been proposed being part of the pathophysiological cascade of Parkinson's disease (PD). However, in living patients, evidence for such dysfunction is scarce. As the disease presumably starts at the enteric level, we studied ganglionic and mitochondrial morphometrics of enteric neurons. We compared 65 ganglia from 11 PD patients without intestinal symptoms and 41 ganglia from 4 age-matched control subjects. We found that colon ganglia from PD patients had smaller volume, contained significantly more mitochondria per ganglion volume, and displayed a higher total mitochondrial mass relative to controls. This suggests involvement of mitochondrial dysfunction in PD at the enteric level. Moreover, in PD patients the mean mitochondrial volume declined in parallel with motor performance. Ganglionic shrinking was evident in the right but not in the left colon. In contrast, mitochondrial changes prevailed in the left colon suggesting that a compensatory increase in mitochondrial mass might counterbalance mitochondrial dysfunction in the left colon but not in the right colon. Reduction in ganglia volume and combined mitochondrial morphometrics had both predictive power to discriminate between PD patients and control subjects, suggesting that both parameters could be used for early discrimination between PD patients and healthy individuals. [less ▲]

The extracellular RNA complement of Escherichia coli

in MicrobiologyOpen (2015)

he secretion of biomolecules into the extracellular milieu is a common and well-conserved phenomenon in biology. In bacteria, secreted biomolecules are not only involved in intra-species communication but ... [more ▼]

he secretion of biomolecules into the extracellular milieu is a common and well-conserved phenomenon in biology. In bacteria, secreted biomolecules are not only involved in intra-species communication but they also play roles in inter-kingdom exchanges and pathogenicity. To date, released products, such as small molecules, DNA, peptides, and proteins, have been well studied in bacte- ria. However, the bacterial extracellular RNA complement has so far not been comprehensively characterized. Here, we have analyzed, using a combination of physical characterization and high-throughput sequencing, the extracellular RNA complement of both outer membrane vesicle (OMV)-associated and OMV-free RNA of the enteric Gram-negative model bacterium Escherichia coli K-12 substrain MG1655 and have compared it to its intracellular RNA comple- ment. Our results demonstrate that a large part of the extracellular RNA com- plement is in the size range between 15 and 40 nucleotides and is derived from specific intracellular RNAs. Furthermore, RNA is associated with OMVs and the relative abundances of RNA biotypes in the intracellular, OMV and OMV- free fractions are distinct. Apart from rRNA fragments, a significant portion of the extracellular RNA complement is composed of specific cleavage products of functionally important structural noncoding RNAs, including tRNAs, 4.5S RNA, 6S RNA, and tmRNA. In addition, the extracellular RNA pool includes RNA biotypes from cryptic prophages, intergenic, and coding regions, of which some are so far uncharacterised, for example, transcripts mapping to the fimA- fimL and ves-spy intergenic regions. Our study provides the first detailed char- acterization of the extracellular RNA complement of the enteric model bacte- rium E. coli. Analogous to findings in eukaryotes, our results suggest the selective export of specific RNA biotypes by E. coli, which in turn indicates a potential role for extracellular bacterial RNAs in intercellular communication. [less ▲]

Analysis of mitochondrial membrane potential in idiopathic Parkinson's disease: A case-control study

Scientific Conference (2014, June 12)

Light microscopy applications in systems biology: opportunities and challenges.

in Cell Communication and Signaling (2013), 11(1), 1-19

Biological systems present multiple scales of complexity, ranging from molecules to entire populations. Light microscopy is one of the least invasive techniques used to access information from various ... [more ▼]

Biological systems present multiple scales of complexity, ranging from molecules to entire populations. Light microscopy is one of the least invasive techniques used to access information from various biological scales in living cells. The combination of molecular biology and imaging provides a bottom-up tool for direct insight into how molecular processes work on a cellular scale. However, imaging can also be used as a top-down approach to study the behavior of a system without detailed prior knowledge about its underlying molecular mechanisms. In this review, we highlight the recent developments on microscopy-based systems analyses and discuss the complementary opportunities and different challenges with high-content screening and high-throughput imaging. Furthermore, we provide a comprehensive overview of the available platforms that can be used for image analysis, which enable community-driven efforts in the development of image-based systems biology. [less ▲]

Analysis of critical transitions in Parkinson's disease

Poster (2011, December 12)

Background Parkinson’s disease is the most common neurodegenerative movement disorder and is clinically characterized by resting tremor, bradykinesia and cogwheel rigidity. The disease affects 1-2% of the ... [more ▼]

Background Parkinson’s disease is the most common neurodegenerative movement disorder and is clinically characterized by resting tremor, bradykinesia and cogwheel rigidity. The disease affects 1-2% of the global population with prevalence in the people above 65 years of age. The main pathological hallmark of Parkinson’s disease is a progressive loss of dopaminergic neurons in the substantia nigra. Therefore, one important challenge is to improve the understanding of regime shifts between health and disease states. Improving predictions of critical transitions triggering the onset of parkinsonian phenotypes could contribute to the improvement of preventive treatments. Methods Based on cellular models, we will use the mathematical concept of critical transitions to create a toolbox for potentially predicting tipping points towards cellular Parkinson’s disease phenotypes, e.g. mitochondrial dysfunction. Experimentally, we will induce and analyze potential critical transitions in the SH-SY5Y cell line. To do this, we will apply Parkinson’s disease relevant chemical and genetic perturbations and analyze multiple scales of the resulting temporal system behavior. We will combine high content imaging with genetic and biochemical data. A significant informatics challenge arises from the aim to perform the analysis of high time-resolved 3D imaging data. We are therefore developing an automated image analysis pipeline that relies on latest technologies and techniques, such as 3D deconvolution and 3D particle tracking. This pipeline will be applied to study parameters, such as mitochondrial dynamics, which include for instance velocity, morphology, and spatial organization. [less ▲]