Bruck syndrome is a rare autosomal recessive disorder characterized by increased bone fragility and joint contractures similar to those in arthrogryposis and is known to be associated with mutations in the FKBP10 (FKBP prolyl isomerase 10) and PLOD2 (Procollagen-Lysine,2-Oxoglutarate 5-Dioxygenase 2) genes. These genes encode endoplasmic reticulum proteins that play an important role in the biosynthesis of type I collagen, which in turn affects the structure and strength of connective tissues and bones in the body. Mutations are associated with disturbances in both the primary collagen chain and its post-translational formation, but the mechanism by which mutations lead to Bruck syndrome phenotypes has not been determined, not only because of the small number of patients who come to the attention of researchers but also because of the lack of disease models. In our work, we investigated the cellular effects of two forms of the wild-type PLOD2 gene, as well as the PLOD2 gene with homozygous mutation c.1885A>G (p.Thr629Ala). The synthesized genetic constructs were transfected into HEK293 cell line and human skin fibroblasts (DF2 line). The localization of PLOD2 protein in cells and the effects caused by the expression of different isoforms—long, short, and long with mutation—were analyzed. In addition, the results of the transcriptome analysis of a patient with Bruck syndrome, in whom this mutation was detected, are presented.
Huntington's disease (HD) is one of the human neurodegenerative diseases for which there is no effective treatment. Therefore, there is a strong demand for a novel neuroprotective agent that can alleviate its course. Fullerene derivatives are considered to be such agents; however, they need to be comprehensively investigated in model organisms. In this work, neuroprotective activity of C60(OH)30 and C120O(OH)44 fullerenols was analyzed for the first time in a Drosophila transgenic model of HD. Lifespan, behavior, oxidative stress level and age-related neurodegeneration were assessed in flies with the pathogenic Huntingtin protein expression in nerve cells. Feed supplementation with hydroxylated C60 fullerene and C120O dimer oxide molecules was shown to diminish the oxidative stress level and neurodegenerative processes in the flies' brains. Thus, fullerenes displayed neuroprotective activity in this model.
Parkinson's disease (PD) is a neurodegenerative disease characterised by the formation of Lewy bodies and progressive loss of dopaminergic (DA) neurons in the substantia nigra. Lewy bodies mainly consist of alpha-synuclein, which plays a critical role in the pathophysiology of PD. The alpha-synuclein is encoded by the SNCA gene and is the first identified gene associated with hereditary PD. Currently, there are at least six disease-associated mutations in alpha-synuclein that cause dominantly inherited familial forms of PD. Targeted expression of human SNCA.WT/SNCA.A30P/SNCA.A53T gene in Drosophila melanogaster over specific times employing a temperature-dependent UAS/GAL4 - GAL80 system allows for the evaluation of neurodegenerative processes. In this study, SNCA was expressed only in the adult stage of Drosophila development for 1 or 2 weeks, followed by repression of gene expression for the rest of the fly's life. It was demonstrated that the level of pathology significantly depends on the duration of alpha-synuclein expression. SNCA gene expression over a longer period of time caused the death of DA neurons, decreased levels of dopamine and locomotor ability. In this case, the observed neurodegenerative processes correlated with the accumulation of alpha-synuclein in the Drosophila brain. Importantly, repression of alpha-synuclein expression led to elimination of the soluble protein fraction, in contrast to the insoluble fraction. No further significant development of characteristic signs of pathology was observed after the alpha-synuclein expression was blocked. Thus, we suggest that reduction of alpha-synuclein expression alone contributes to slowing down the development of PD-like symptoms.
Drosophila melanogaster is one of the most famous insects in biological research. It is widely used to analyse functions of different genes. The phosphatidylcholine lysophospholipase gene swiss cheese was initially shown to be important in the fruit fly nervous system. However, the role of this gene in non-nervous cell types has not been elucidated yet, and the evolutional explanation for the conservation of its function remains elusive. In this study, we analyse expression pattern and some aspects of the role of the swiss cheese gene in the fitness of Drosophila melanogaster. We describe the spatiotemporal expression of swiss cheese throughout the fly development and analyse the survival and productivity of swiss cheese mutants. We found swiss cheese to be expressed in salivary glands, midgut, Malpighian tubes, adipocytes, and male reproductive system. Dysfunction of swiss cheese results in severe pupae and imago lethality and decline of fertility, which is impressive in males. The latter is accompanied with abnormalities of male locomotor activity and courtship behaviour, accumulation of lipid droplets in testis cyst cells and decrease in spermatozoa motility. These results suggest that normal swiss cheese is important for Drosophila melanogaster fitness due to its necessity for both specimen survival and their reproductive success.
Various neurodegenerative disorders are associated with human NTE/PNPLA6 dysfunction. Mechanisms of neuropathogenesis in these diseases are far from clearly elucidated. Hereditary spastic paraplegia belongs to a type of neurodegeneration associated with NTE/PNLPLA6 and is implicated in neuron death. In this study, we used Drosophila melanogaster to investigate the consequences of neuronal knockdown of swiss cheese (sws)—the evolutionarily conserved ortholog of human NTE/PNPLA6—in vivo. Adult flies with the knockdown show longevity decline, locomotor and memory deficits, severe neurodegeneration progression in the brain, reactive oxygen species level acceleration, mitochondria abnormalities and lipid droplet accumulation. Our results suggest that SWS/NTE/PNPLA6 dysfunction in neurons induces oxidative stress and lipid metabolism alterations, involving mitochondria dynamics and lipid droplet turnover in neurodegeneration pathogenesis. We propose that there is a complex mechanism in neurological diseases such as hereditary spastic paraplegia, which includes a stress reaction, engaging mitochondria, lipid droplets and endoplasmic reticulum interplay.
Glia are crucial for the normal development and functioning of the nervous system in many animals. Insects are widely used for studies of glia genetics and physiology. Drosophila melanogaster surface glia (perineurial and subperineurial) form a blood–brain barrier in the central nervous system and blood–nerve barrier in the peripheral nervous system. Under the subperineurial glia layer, in the cortical region of the central nervous system, cortex glia encapsulate neuronal cell bodies, whilst in the peripheral nervous system, wrapping glia ensheath axons of peripheral nerves. Here, we show that the expression of the evolutionarily conserved swiss cheese gene is important in several types of glia. swiss cheese knockdown in subperineurial glia leads to morphological abnormalities of these cells. We found that the number of subperineurial glia nuclei is reduced under swiss cheese knockdown, possibly due to apoptosis. In addition, the downregulation of swiss cheese in wrapping glia causes a loss of its integrity. We reveal transcriptome changes under swiss cheese knockdown in subperineurial glia and in cortex + wrapping glia and show that the downregulation of swiss cheese in these types of glia provokes reactive oxygen species acceleration. These results are accompanied by a decline in animal mobility measured by the negative geotaxis performance assay.
Herein we report on the synthesis, structural characterization and photophysical properties of cyclometalated Pt(II) complexes [Pt(N^C)(PPh2(C6H4COOH))Cl] (where N^C ligands are 2-phenylpyridine, (2-benzofuran-3-yl)pyridine, and (2-benzo[b]tiophen-3-yl)pyridine) and their conjugates with the histidine-containing RRRRRRRRRRHVLPKVQA peptide. This peptide contains the RHVLPKVQA sequence, which is responsible for antiamyloid activity, and the Arg9 RRRRRRRRR domain, which shows improved translocation through cell membranes. The chemistry underpinning the conjugation is regioselective complexation between Pt(II) complexes and histidine residue in the peptide. The prepared conjugates have been characterized using high-resolution mass spectrometry and NMR spectroscopy. It was shown that the conjugates are easily soluble in aqueous media and display emission band profiles essentially similar to those of the starting complexes but considerably higher luminescence quantum yield and much longer phosphorescence lifetime. MTT assay on HeLa cell culture revealed no cytotoxicity up to 10 μM after 24 h of incubation. Ex vivo and in vivo neuroimaging experiments on both wild and amyloid peptide expressing strains of Drosophila melanogaster revealed that the conjugates penetrate the blood-brain barrier and are evenly distributed throughout the brain independently of the strain used.
Глиальные клетки (ГК) являются наиболее распространенным типом клеток в центральной нервной системе. Интерес к ним значительно увеличился за последние десятилетия по мере осознания того, что глия является не только «опорными» клетками для нейронов, но также регулирует важные аспекты развития и функционирования нервной системы. У позвоночных ГК выполняют опорную, трофическую, секреторную, разграничительную и защитную функции. Несмотря на то, что нервная система Drosophila melanogaster относительно проста по своей структуре, ей присущи характеристики сложно устроенной глии млекопитающих. Схожесть глии Drosophila melanogaster и млекопитающих на молекулярном и морфологическом уровне дает возможность предположить, что исследование глии беспозвоночных позволит лучше понять основные вопросы развития глии у млекопитающих. Использование Drosophila melanogaster дает возможность изучать различные нейрон-глиальные взаимодействия в интактном организме, а использование широкого набора молекулярно-генетических методов позволяет исследовать фундаментальные вопросы природы глии. В обзоре дана классификация глиальных клеток Drosophila melanogaster, описаны известные на сегодняшний день функции всех типов глии насекомого, а также проведено сравнение функций разных типов глиальных клеток млекопитающих и дрозофилы.
Neuropathy target esterase (NTE) is a molecular target for the organophosphorus compound-induced delayed neuropathy (OPIDN) and also one of the genetic factors responsible for the development of the hereditary spastic paraplegia (HSP), characterized by axon degeneration of motoneurons causing progressive lower-limb spastic paralysis. Both HSP and OPIDN are characterized by the distal axonopathy. The molecular mechanisms underlying the axonopathy involved in HSP and OPIDN are poorly understood. In order to have a better understanding of the mechanisms that NTE is involved in, we used one of the homologs, human NTE. Swiss cheese (sws) is a Drosophila melanogaster ortholog of NTE with 39% homology. Mutations in sws as it was shown before lead to age-dependent neurodegeneration, structure alteration of glia cells, and reduced insect life span. To study SWS functions, we used the system of the third-instar larval neuromuscular junctions of D. melanogaster. In this study, we show that mutations in sws (sws1 and sws76−1 ) and SWS knockdown alter neuromuscular junction's morphology and synaptic microtubules organization.
The identity of neuronal cell types is established and maintained by the expression of neuronal genes coding for ion channels, neurotransmitters, and neuropeptides, among others. Some of these genes have been shown to affect lifespan; however, their role in lifespan control remains largely unclear. The Drosophila melanogaster gene Lim3 encodes a transcription factor involved in complicated motor neuron specification networks. We previously identified Lim3 as a candidate gene affecting lifespan. To obtain direct evidence of the involvement of Lim3 in lifespan control, Lim3 overexpression and RNAi knockdown were induced in the nervous system and muscles of Drosophila using the GAL4-UAS binary system. We demonstrated that Lim3 knockdown in the nervous system increased survival at an early age and that Lim3 knockdown in muscles both increased survival at an early age and extended median lifespan, directly establishing the involvement of Lim3 in lifespan control. Lim3 overexpression in nerves and muscles was deleterious and led to lethality and decreased lifespan, respectively. Lim3 misexpression in both nerves and muscles increased locomotion regardless of changes in lifespan, which indicated that the effects of Lim3 on lifespan and locomotion can be uncoupled. Decreased synaptic activity was observed in the neuromuscular junctions of individuals with Lim3 overexpression in muscles, in association with decreased lifespan. However, no changes in NMJ activity were associated with the positive shift in locomotion observed in all misexpression genotypes. Our data suggested that modifications in the microtubule network may be induced by Lim3 misexpression in muscles and cause an increase in locomotion.
This study provides further insight into the molecular mechanisms that control neurotransmitter release. Experiments were performed on larval neuromuscular junctions of transgenic Drosophila melanogaster lines with different levels of human amyloid precursor protein (APP) production. To express human genes in motor neurons of Drosophila , the UAS-GAL4 system was used. Human APP gene expression increased the number of synaptic boutons per neuromuscular junction. The total number of active zones, detected by Bruchpilot protein puncta distribution, remained unchanged; however, the average number of active zones per bouton decreased. These disturbances were accompanied by a decrease in frequency of miniature excitatory junction potentials without alteration in random nature of spontaneous quantal release. Similar structural and functional changes were observed with co-overexpression of human APP and β-secretase genes. In Drosophila line with expression of human amyloid- β 42 peptide itself, parameters analyzed did not differ from controls, suggesting the specificity of APP effects. These results confirm the involvement of APP in synaptogenesis and provide evidence to suggest that human APP overexpression specifically disturbs the structural and functional organization of active zone and results in altered Bruchpilot distribution and lowered probability of spontaneous neurotransmitter release.