The accumulation of damaged mitochondria causes the death of dopaminergic neurons. The Parkin-mediated mitophagy pathway functions to remove these mitochondria from cells. Targeting this pathway ...represents a therapeutic strategy for several neurodegenerative diseases, most notably Parkinson's disease. We describe a discovery pipeline to identify small molecules that increase Parkin recruitment to damaged mitochondria and ensuing mitophagy. We show that ROCK inhibitors promote the activity of this pathway by increasing the recruitment of HK2, a positive regulator of Parkin, to mitochondria. This leads to the increased targeting of mitochondria to lysosomes and removal of damaged mitochondria from cells. Furthermore, ROCK inhibitors demonstrate neuroprotective effects in flies subjected to paraquat, a parkinsonian toxin that induces mitochondrial damage. Importantly, parkin and rok are required for these effects, revealing a signaling axis which controls Parkin-mediated mitophagy that may be exploited for the development of Parkinson's disease therapeutics.
Failures in mitophagy, a process by which damaged mitochondria are cleared, results in neurodegeneration, while enhancing mitophagy promotes the survival of dopaminergic neurons. Using an artificial ...intelligence platform, we employed a natural language processing approach to evaluate the semantic similarity of candidate molecules to a set of well-established mitophagy enhancers. Top candidates were screened in a cell-based mitochondrial clearance assay. Probucol, a lipid-lowering drug, was validated across several orthogonal mitophagy assays. In vivo, probucol improved survival, locomotor function, and dopaminergic neuron loss in zebrafish and fly models of mitochondrial damage. Probucol functioned independently of PINK1/Parkin, but its effects on mitophagy and in vivo depended on ABCA1, which negatively regulated mitophagy following mitochondrial damage. Autophagosome and lysosomal markers were elevated by probucol treatment in addition to increased contact between lipid droplets (LDs) and mitochondria. Conversely, LD expansion, which occurs following mitochondrial damage, was suppressed by probucol and probucol-mediated mitophagy enhancement required LDs. Probucol-mediated LD dynamics changes may prime the cell for a more efficient mitophagic response to mitochondrial damage.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We have employed artificial intelligence to streamline the small molecule drug screening pipeline and identified the cholesterol-reducing compound probucol in the process. Probucol augmented ...mitophagy and prevented loss of dopaminergic neurons in flies and zebrafish challenged with mitochondrial toxins. Further dissection of the mechanism of action led to the identification of ABCA1, the target of probucol, as a mitophagy modulator. Probucol treatment regulates lipid droplet dynamics during mitophagy and ABCA1 is required for these effects. Here we will summarize the combination of in silico and cell-based screening that led us to identify and characterize probucol as a compound that enhances mitophagy and include thoughts about future directions for the topics explored in our study.
Abbreviations: ABCA1: ATP binding cassette transporter protein 1; ATP: Adenosine tri-phosphate; CCCP: carbonyl cyanide m-chlorophenylhydrazone; DsRed: Discosoma red; FDA: Food and drug administration; GFP: Green fluorescent protein; LAMP: lysosome-associated membrane glycoproteins; LD: Lipid droplet; PD: Parkinson's disease; PINK: PTEN-induced kinase
Mitochondrial damage and impaired mitophagy underly the pathogenesis of Parkinson’s disease (PD). Amongst the loci implicated with onset of familial PD are several genes that encode proteins which ...mediate a common goal: the removal of damaged mitochondria. Mitochondria, like other organelles, are subject to damage, which may affect lipids, DNA or proteins. The level of damage the cell can endure exists on a spectrum and there are systems in place to mitigate mitochondrial damage. Pathogenic mutations in PINK1 and PRKN cause early-onset familial PD because they compromise mitophagy, a pathway employed by dopaminergic neurons to handle mitochondrial damage. The accumulation of dysfunctional mitochondria produces reactive oxygen species and further perpetuates damage in the mitochondrial milieu. Once a critical threshold of damage is crossed, a cell death program is executed leading to loss of dopaminergic neurons in the substantia nigra, the defining PD pathology.This work sought to identify small molecules and molecular mechanisms that potentiate the mitophagy pathway, which may be advantageous for dopaminergic neurons susceptible to mitochondrial damage in the context of PD. Importantly, we aimed to identify molecules which function without induction of mitochondrial damage and/or apoptosis. The hope is that by bolstering mitophagy, loss of dopaminergic neurons will be slowed, leading to reduced PD-related phenotypes that arise consequently. Fortuitously, several model organisms which reflect PD pathology and systemic characteristics of the disease are available. Molecules that enhance mitophagy were tested in preclinical PD models of mitochondrial damage. This pipeline led to the identification of ROCK inhibitors and probucol as compounds that enhanced mitophagy and demonstrably reduced PD-related phenotypes in model organisms reflecting mitochondrial damage. Dissection of the mechanisms through which the molecules function illuminated new aspects of mitophagy and confirmed the idea that mitophagy enhancers may be a viable strategy for the development of PD therapeutics. Additionally, rhomboid-7 negatively regulates basal mitophagy in the dopaminergic neurons of flies. This supports the idea of PARL inhibitors as another class of mitophagy agonists and potential PD therapeutics. Using a robust eye degeneration phenotype, rhomboid-7’s possible epistatic relationships were investigated.
Failures in mitophagy, a process by which damaged mitochondria are cleared, results in neurodegeneration, while enhancing mitophagy promotes the survival of dopaminergic neurons. Using an artificial ...intelligence platform, we employed a natural language processing approach to evaluate the semantic similarity of candidate molecules to a set of well-established mitophagy enhancers. Top candidates were screened in a cell-based mitochondrial clearance assay. Probucol, a lipid-lowering drug, was validated across several orthogonal mitophagy assays. In vivo, probucol improved survival, locomotor function, and dopaminergic neuron loss in zebrafish and fly models of mitochondrial damage. Probucol functioned independently of PINK1/Parkin, but its effects on mitophagy and in vivo depended on ABCA1, which negatively regulated mitophagy following mitochondrial damage. Autophagosome and lysosomal markers were elevated by probucol treatment in addition to increased contact between lipid droplets (LDs) and mitochondria. Conversely, LD expansion, which occurs following mitochondrial damage, was suppressed by probucol and probucol-mediated mitophagy enhancement required LDs. Probucol-mediated LD dynamics changes may prime the cell for a more efficient mitophagic response to mitochondrial damage. Failures in mitophagy, a process by which damaged mitochondria are cleared, results in neurodegeneration, while enhancing mitophagy promotes the survival of dopaminergic neurons. This study shows that the effects of Probucol on lipid droplet expansion can augment mitophagy in neurons, leading to locomotor improvements in zebrafish and fly models of Parkinson’s disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this issue of Cell Chemical Biology, Tichá et al. (2017) report a novel class of highly potent and selective rhomboid inhibitors. Rhomboids are implicated in several devastating human afflictions ...including malaria, diabetes, cancer, and Parkinson’s disease (PD), making them important drug targets for future therapeutics.
In this issue of Cell Chemical Biology, Tichá et al. (2017) report a novel class of highly potent and selective rhomboid inhibitors. Rhomboids are implicated in several devastating human afflictions including malaria, diabetes, cancer, and Parkinson’s disease (PD), making them important drug targets for future therapeutics.
Orobanche laxissima Uhlich & Rätzel (Orobanchaceae) is a polyphagous root parasitic plant distributed in the Caucasus Mountains and Transcaucasia; especially Russia, Georgia, Armenia, Azerbaijan, ...N.E. Turkey (Piwowarczyk et al. 2019). It infects many wild or sometimes cultivated trees and shrubs, such as Betulaceae, Oleaceae, Fagaceae, Aceraceae, Cornaceae, usually Fraxinus L., Fagus L., Carpinus L. (Piwowarczyk et al. 2019, 2020). Punica granatum L. (Lythraceae), commonly known as pomegranate, is native to the Caucasus, the Himalayas in North Pakistan and Northern India, and is widely cultivated, e.g. in USA and throughout the Mediterranean. Pomegranate is one of the first domesticated fruits and have been used in folk medicine or as a food for centuries. Fruit, seed, leaves, flower, root, or barks extracts have extensive medicinal properties (Shaygannia et al. 2015). Field surveys conducted in south-eastern Georgia in May 2019 revealed extensive infestations of O. laxissima on the roots of P. granatum in one locality in Kakheti Province, near Sighnaghi (41°37,4 N, 45°56,3 E, 480 m elevation), in roadside or hills scrub and cultivated areas of pomegranate. The infection was confirmed by verifying the attachment of the Orobanche to the Punica root. The population of the parasite consisted of at least a ca. thousand shoots, sometimes in one clump was ca. 100 individuals. A single plant of pomegranate was parasitized by few to c.a. a hundred of broomrape plants, and 10 to 20% of the ca. 1 ha location was infested. The main botanical features of the O. laxissima are: i) stem simple, (10-)25-40(-100) cm high, with haustoria; ii) inflorescence usually long to short cylindrical or lax, usually many-flowered; iii) calyx-segments entire or bidentate, rarely with 4 teeth; iv) corolla (16-)22-24(-31) mm long, tubular-bell-shaped; purple, pink, rarely dirty yellow, light brown; v) stigma purple, orange, or yellow (Piwowarczyk et al. 2019, 2020). For molecular analysis, total genomic DNA was extracted from the sample and the plastid gene rbcL (rubisco large subunit) was sequenced and amplified as described in Piwowarczyk et al. (2015). The sequence (1231 bp) was deposited in GenBank (MN384886). BLAST search found that it was most similar to (Query Cover 100%, Per Ident. 100%) O. laxissima (KR260928). To the best of our knowledge, this is the first report of a O. laxissima parasitizing P. granatum. O. laxissima appearing in large numbers on singles pomegranate shrubs can weaken the plants, and reduce flowering and fruiting. In the Caucasus region, O. laxissima was observed in mesophilic forests and shrubs, but our report suggests the possibility of a potential spread to neighboring cultivated areas, especially fruit trees and shrubs. Until now, only one report of pathogenic plants was documented for P. granatum, included Phelipanche aegyptiaca (Pers.) Pomel and O. crenata Forssk. in Israel (Dor et al. 2014).
Horizontal gene transfer (HGT) is a process that allows genetic material to flow between even distantly related organisms. It is primarily observed in bacteria and protists but also in different ...lineages of eucaryotes. The first HGT cases in plants were discovered at the beginning of the 21st century and have been intensively studied ever since. Researchers have placed particular emphasis on the plant kingdom, especially parasitic plants. This review presents the current state of knowledge about this phenomenon in plants, with a special focus on parasitic plants. Among the described factors facilitating HGT, close physical contact between organisms is believed to be one of the most important. It is noted especially in the case of parasitism and similar relationships. For that reason, reported occurrences of this phenomenon in holoparasites, hemiparasites, and mycoheterotrophic plants are compared. The mechanisms responsible for HGT in plants still remain unclear, however, the studies described here suggest that both DNA and RNA may play a role as a carrier in that process. Also, the transfer between genomes of different organelles in the cell, intracellular gene transfer (IGT), and its relationships with HGT are described. The occurrence of the HGT and IGT phenomena concerning different genomes: nuclear, mitochondrial, and plastid is discussed in the review. Finally, some future areas of research in the field are proposed.
Abstract
Peopling of Central Europe by Middle Pleistocene hominids is highly debatable, mainly due to the relatively harsh climatic and environmental conditions that require cultural and anatomical ...adjustments. At least several archaeological sites certify human occupation in the region dated back to MIS 13-11, but they represent open-air settlements. Based on the new fieldwork conducted in Tunel Wielki Cave, we can date the human occupation traces in the cave to MIS 14-12. Bipolar-on-anvil knapping technique prevails in the lithic assemblage, made exclusively in flint. The obtained results have given ground for studying the frontiers of human oikumene and the required cultural adaptive abilities.
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