Mitochondrial Dysfunction in Dopaminergic Neurons Derived from Patients with LRRK2- and SNCA-Associated Genetic Forms of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease. Some cases of PD may be caused by genetic factors, among which mutations in the LRRK2 and SNCA genes play an important role. To develop effective neuroprotective strategies for PD, it is important to diagnose the disease at the earliest stages of the neurodegenerative process. Therefore, the detection of diagnostic and prognostic markers of Parkinson's disease (PD) is an urgent medical need. Advances in induced pluripotent stem cell (iPSC) culture technology provide new opportunities for the search for new biomarkers of PD and its modeling in vitro. In our work, we used a new technology for multiplex profiling of gene expression using barcoding on the Nanostring platform to assess the activity of mitochondrial genes on iPSC-derived cultures of dopaminergic neurons obtained from patients with LRRK2- and SNCA-associated genetic forms PD and a healthy donor. Electron microscopy revealed ultrastructural changes in mitochondria in both LRRK2 and SNCA mutant cells, whereas mitochondria in cells from a healthy donor were normal. In a culture with the SNCA gene mutation, the ratio of the area occupied by mitochondria to the total area of the cytoplasm was significantly lower than in the control and in the line with the LRRK2 gene mutation. Transcriptome analysis of 105 mitochondria proteome genes using the Nanostring platform revealed differences between the diseased and normal cells in the activity of genes involved in respiratory complex function, the tricarboxylic acid cycle, ATP production, mitochondria-endoplasmic reticulum interaction, mitophagy, regulation of calcium concentration, and mitochondrial DNA replication.

[Molecular Mechanisms of Interactions between Mitochondria and the Endoplasmic Reticulum: A New Look at How Important Cell Functions are Supported]

Interactions between the endoplasmic reticulum (ER) and mitochondria have received insufficient attention until recently. However, distorted contacts between the ER and mitochondria were identified as an important factor in the etiopathogenesis of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. In view of these new data, the mechanisms of ER-mitochondrial interactions are necessary to study in detail in order to develop new diagnostic and therapeutic approaches to neurodegenerative diseases and to extend basic knowledge of the physiology of the eukaryotic cell. The review focuses on the functions of mitochondria-associated ER membranes (MAMs). Structural elements of the MAM system, their contributions to the vital cell functions (calcium and lipid homeostasis, autophagy, fusion and division of mitochondria, and the regulation of their number), and the role of MAM dysfunctions in the pathogenesis of various neurodegenerative diseases are considered.

[Viral antigens in kidney biopsies of children with glomerulonephritis]

A relationship between clinical forms of glomerulonephritis and incidence of viral antigens in renal tissue was revealed: Hepatitis B virus antigens (HBsAg) are more frequently detected in the glomeruli in the patients with nephrotic glomerulonephritis, Herpes simplex antigens are detected in the glomeruli in mixed glomerulonephritis, and cytomegaloviral and Herpes simplex antigens are detected in the epithelium of the proximal canaliculi in patients with hematuric glomerulonephritis. No correlations between the persistence of Herpes simplex type 1, cytomegalovirus, and HBsAg in the renal tissue were detected. HBsAg is detected in the renal tissue mainly in the children without free HBsAg in the blood serum. This may be indicative of an important role of specific immune complexes in the pathogenesis of glomerulonephritis associated with hepatitis B viral infection. The results point to an appreciable contribution of a persistent viral infection to the progress of glomerulonephritis.

[A morphologic analysis of changes in the lungs and kidneys caused by acetyl glyceryl ether phosphorylcholine and limited by verapamil]

Histological analysis of lung and kidney after multiple PAF i.v. injection into rabbits was performed. Under these conditions the effect of previously injected of verapamyl, calcium channel blocker, was studied. It was shown that RAF causes inflammatory reaction with cell infiltration, microcirculation disorders and thrombosis in lung and kidney, which may classify as interstitial nephritis, pneumonitis and vasculitis. Verapamyl inhibits vasospasm, abolishes fibrinogen but does not affect cell infiltration and oedema development. Thus, Ca channel-dependent mechanism of vasospasm and thrombogenesis induced by PAF in vivo is confirmed. Perhaps, another possibilities for realising PAF action in vivo may occur.