scholarly journals Earliest Mechanisms of Dopaminergic Neurons Sufferance in a Novel Slow Progressing Ex Vivo Model of Parkinson Disease in Rat Organotypic Cultures of Substantia Nigra

2019 ◽  
Vol 20 (9) ◽  
pp. 2224 ◽  
Author(s):  
Matteo Dal Ben ◽  
Rosario Bongiovanni ◽  
Simone Tuniz ◽  
Emanuela Fioriti ◽  
Claudio Tiribelli ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Parkinson Disease ◽  
Dopaminergic Neurons ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Ex Vivo Model ◽  
Redox Imbalance ◽  
Clinical Phase ◽  
Protein Clearance ◽  
Persistent Inflammation

The current treatments of Parkinson disease (PD) are ineffective mainly due to the poor understanding of the early events causing the decline of dopaminergic neurons (DOPAn). To overcome this problem, slow progressively degenerating models of PD allowing the study of the pre-clinical phase are crucial. We recreated in a short ex vivo time scale (96 h) all the features of human PD (needing dozens of years) by challenging organotypic culture of rat substantia nigra with low doses of rotenone. Thus, taking advantage of the existent knowledge, the model was used to perform a time-dependent comparative study of the principal possible causative molecular mechanisms undergoing DOPAn demise. Alteration in the redox state and inflammation started at 3 h, preceding the reduction in DOPAn number (pre-diagnosis phase). The number of DOPAn declined to levels compatible with diagnosis only at 12 h. The decline was accompanied by a persistent inflammation and redox imbalance. Significant microglia activation, apoptosis, a reduction in dopamine vesicle transporters, and the ubiquitination of misfolded protein clearance pathways were late (96 h, consequential) events. The work suggests inflammation and redox imbalance as simultaneous early mechanisms undergoing DOPAn sufferance, to be targeted for a causative treatment aimed to stop/delay PD.

Hypokinetic Movement Disorders: Parkinson Disease

2021 ◽  
pp. 576-582
Author(s):  
Sarah M. Tisel ◽  
Bryan T. Klassen
Keyword(s):  
Cell Death ◽  
Substantia Nigra ◽  
Parkinson Disease ◽  
Movement Disorder ◽  
Movement Disorders ◽  
Dopaminergic Neurons ◽  
Microscopic Level ◽  
Rest Tremor ◽  
Macroscopic Level ◽  
Progressive Degeneration

Parkinson disease (PD) is the classic hypokinetic movement disorder and one of the most common and widely recognized neurodegenerative conditions. PD is distinct from parkinsonism, a term that refers to a syndrome of rest tremor, bradykinesia, rigidity, and postural instability. The mechanism behind the progressive degeneration and cell death that result in PD is not precisely understood. Substantia nigra depigmentation occurs on a macroscopic level and loss of dopaminergic neurons and gliosis on a microscopic level.

scholarly journals The potential role of neuroinflammation and transcription factors in Parkinson disease

2017 ◽  
Vol 19 (1) ◽  
pp. 71-80 ◽  
Keyword(s):  
Oxidative Stress ◽  
Transcription Factors ◽  
Substantia Nigra ◽  
Parkinson Disease ◽  
Signaling Pathways ◽  
Dopaminergic Neurons ◽  
Neurodegenerative Disorder ◽  
Brain Regions ◽  
Death Domain

Parkinson disease (PD) is a neurodegenerative disorder characterized by dopaminergic neurons affected by inflammatory processes. Post-mortem analyses of brain and cerebrospinal fluid from PD patients show the accumulation of proinflammatory cytokines, confirming an ongoing neuroinflammation in the affected brain regions. These inflammatory mediators may activate transcription factors—notably nuclear factor κB, Ying-Yang 1 (YY1), fibroblast growth factor 20 (FGF20), and mammalian target of rapamycin (mTOR)—which then regulate downstream signaling pathways that in turn promote death of dopaminergic neurons through death domain-containing receptors. Dopaminergic neurons are vulnerable to oxidative stress and inflammatory attack. An increased level of inducible nitric oxide synthase observed in the substantia nigra and striatum of PD patients suggests that both cytokine—and chemokine-induced toxicity and inflammation lead to oxidative stress that contributes to degeneration of dopaminergic neurons and to disease progression. Lipopolysaccharide activation of microglia in the proximity of dopaminergic neurons in the substantia nigra causes their degeneration, and this appears to be a selective vulnerability of dopaminergic neurons to inflammation. In this review, we will look at the role of various transcription factors and signaling pathways in the development of PD.

Toxic Equine Parkinsonism: An Immunohistochemical Study of 10 Horses With Nigropallidal Encephalomalacia

2011 ◽  
Vol 49 (2) ◽  
pp. 398-402 ◽  
Author(s):  
H. T. Chang ◽  
W. K. Rumbeiha ◽  
J. S. Patterson ◽  
B. Puschner ◽  
A. P. Knight
Keyword(s):  
Tyrosine Hydroxylase ◽  
Substantia Nigra ◽  
Parkinson Disease ◽  
Globus Pallidus ◽  
Dopaminergic Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Large Animal Model ◽  
Substantia Nigra Pars Reticulata ◽  
Large Animal ◽  
Cytoplasmic Inclusions

Chronic ingestion of yellow star thistle ( Centaurea solstitialis) or Russian knapweed ( Acroptilon repens) causes nigropallidal encephalomalacia (NPE) in horses with an abrupt onset of neurologic signs characterized by dystonia of lips and tongue, inability to prehend food, depression, and locomotor deficits. The objectives of this study were to reexamine the pathologic alterations of NPE and to conduct an immunohistochemistry study using antibodies to tyrosine hydroxylase and α-synuclein, to determine whether NPE brains show histopathologic features resembling those in human Parkinson disease. Results confirm that the NPE lesions are located within the substantia nigra pars reticulata, sparing the cell bodies of the dopaminergic neurons in the substantia nigra pars compacta, and in the rostral portion of the globus pallidus, with partial disruption of dopaminergic (tyrosine hydroxylase–positive) fibers passing through the globus pallidus. No abnormal cytoplasmic inclusions like the Lewy bodies of human Parkinson disease were seen in these NPE brains. These findings indicate that equine NPE may serve as a large animal model of environmentally acquired toxic parkinsonism, with clinical phenotype directly attributable to lesions in globus pallidus and substantia nigra pars reticulata rather than to the destruction of dopaminergic neurons.

scholarly journals Stretch increases alveolar type 1 cell number in fetal lungs through ROCK-Yap/Taz pathway

2021 ◽  
Author(s):  
Tram Mai Nguyen ◽  
Johannes van der Merwe ◽  
Linda Elowsson Rendin ◽  
Anna-Karin Larsson-Callerfelt ◽  
Jan Deprest ◽  
...  
Keyword(s):  
Lung Development ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Fluid Pressure ◽  
Fetal Lung ◽  
In Vivo Model ◽  
Alveolar Type ◽  
Ex Vivo Model

Accurate fluid pressure in the fetal lung is critical for its development, especially at the beginning of the saccular stage when alveolar epithelial type 1 (AT1) and type 2 (AT2) cells differentiate from the epithelial progenitors. Despite our growing understanding of the role of physical forces in lung development, the molecular mechanisms that regulate the transduction of mechanical stretch to alveolar differentiation remain elusive. To simulate lung distension, we optimized both an ex vivo model with precision cut lung slices and an in vivo model of fetal tracheal occlusion. Increased mechanical tension showed to improve alveolar maturation and differentiation towards AT1. By manipulating ROCK pathway, we demonstrate that stretch-induced Yap/Taz activation promotes alveolar differentiation towards AT1 phenotype via ROCK activity. Our findings show that balanced ROCK-Yap/Taz signaling is essential to regulate AT1 differentiation in response to mechanical stretching of the fetal lung, which might be helpful in improving lung development and regeneration.

Osteogenic Mechanisms of Basal Ganglia Calcification and its ex vivo Model in the Hypoparathyroid Milieu

Endocrinology ◽  
2021 ◽  
Vol 162 (4) ◽  
Author(s):  
Parmita Kar ◽  
Tabin Millo ◽  
Soma Saha ◽  
Samrina Mahtab ◽  
Shipra Agarwal ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Gray Matter ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Ex Vivo Model ◽  
Caudate Nuclei ◽  
Basal Ganglia Calcification ◽  
Cortical Gray Matter ◽  
Autopsy Tissues ◽  
High Phosphate

Abstract Context Basal-ganglia calcification (BGC) is common (70%) in patients with chronic hypoparathyroidism. Interestingly, cortical gray matter is spared from calcification. The mechanism of BGC, role of hyperphosphatemia, and modulation of osteogenic molecules by parathyroid hormone (PTH) in its pathogenesis is not clear. Objective We assessed the expression of a large repertoire of molecules with proosteogenic or antiosteogenic effects, including neuroprogenitor cells in caudate, dentate, and cortical gray matter from normal autopsy tissues. The effect of high phosphate and PTH was assessed in an ex vivo model of BGC using striatum tissue culture of the Sprague-Dawley rat. Methods The messenger RNA and protein expression of 39 molecules involved in multiple osteogenic pathways were assessed in 25 autopsy tissues using reverse-transcriptase polymerase chain reaction, Western blot, and immunofluorescence. The striatal culture was maintained in a hypoparathyroid milieu for 24 days with and without (a) high phosphate (10-mm β-glycerophosphate) and (b) PTH(1-34) (50 ng/mL Dulbecco’s modified Eagle’s medium–F12 media) for their effect on striatal calcification and osteogenic molecules. Results Procalcification molecules (osteonectin, β-catenin, klotho, FZD4, NT5E, LRP5, WNT3A, collagen-1α, and SOX2-positive neuroprogenitor stem cells) had significantly higher expression in the caudate than gray matter. Caudate nuclei also had higher expression of antiosteogenic molecules (osteopontin, carbonic anhydrase-II [CA-II], MGP, sclerostin, ISG15, ENPP1, and USP18). In an ex vivo model, striatum culture showed an increased propensity for calcified nodules with mineral deposition similar to that of bone tissue on Fourier-transformed infrared spectroscopy, alizarin, and von Kossa stain. Mineralization in striatal culture was enhanced by high phosphate and decreased by exogenous PTH through increased expression of CA-II. Conclusion This study provides a conceptual advance on the molecular mechanisms of BGC and the possibility of PTH therapy to prevent this complication in a hypoparathyroid milieu.

Neuroinflammation caused by activated microglia and astrocytes can contribute to the progression of pathogenic damage to substantia nigra neurons, playing a role in Parkinson's disease progression

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Oxidative Stress ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Substantia Nigra ◽  
Mitochondrial Dysfunction ◽  
Dopaminergic Neurons ◽  
Molecular Mechanisms ◽  
High Energy ◽  
Molecular Pathways ◽  
Activated Microglia

Parkinson's disease progresses by a number of regionally specific cellular and molecular mechanisms. Furthermore, these pathways interact and have an influence on one another in both normal and pathological conditions. Neuroinflammation caused by activated microglia and astrocytes can contribute to the progression of pathogenic damage to substantia nigra (SN) neurons. Similarly, oxidative stress may be caused by a variety of stressors, such as contaminants in the environment or age-related mitochondrial dysfunction, leading to the production of reactive oxygen species (ROS). Dopamine auto-oxidation is a significant generator of ROS in dopaminergic neurons, resulting in neuronal oxidative stress. The high energy demands of dopaminergic neurons may result in mitochondrial dysfunction and oxidative damage as they age. Because mitophagy clears dysfunctional mitochondria from SN neurons, mutation-related abnormalities in autophagy of defective proteins might allow damaging proteins to accumulate in the cell. Because the effects of aging on these molecular pathways and cellular activities are unknown, further study into these molecular pathways and their connections in normal and sick states will be essential for developing disease-specific therapies.

A Novel Porcine Ex Vivo Retina Culture Model for Oxidative Stress Induced by H2O2

2017 ◽  
Vol 45 (1) ◽  
pp. 11-25 ◽  
Author(s):  
José Hurst ◽  
Sandra Kuehn ◽  
Adelina Jashari ◽  
Teresa Tsai ◽  
Karl Ulrich Bartz-Schmidt ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Mechanisms ◽  
Ganglion Cells ◽  
Ex Vivo ◽  
Laboratory Animals ◽  
Ex Vivo Model ◽  
Cd11b Expression ◽  
Hsp70 Mrna ◽  
New Therapeutic Approaches ◽  
Culture Models

Oxidative stress is a key player in many ophthalmic diseases. However, the role of oxidative stress in most degenerative processes is not yet known. Therefore, accurate and practical models are required to efficiently screen for therapeutics. Porcine eyes are closely related to the human eye, and can be obtained from the abattoir as a by-product of the food industry. Therefore, they offer excellent opportunities for the development of culture models with which to pre-screen potential therapies, while reducing the use of laboratory animals. To induce oxidative stress, organotypic cultures of porcine retina were treated with different doses of hydrogen peroxide (H2O2; 100, 300 and 500μM) for three hours. On days 3 and 8, the retinas were conserved for histological and Western blotting analyses and for evaluation of gene expression, which determined the number of retinal ganglion cells (RGCs), the activation state of glial cells, and the expression levels of several oxidative stress markers. H2O2 treatment led to a reduction in the number of RGCs and to an increase in apoptotic RGCs. In addition, a dose-dependent increase of microglia and an elevation of CD11b expression was observed. On day 3, a reduction of IL-1β, and an increase of iNOS, as well as of HSP70 mRNA were found. On day 8, an increase in TNF-α and IL-1β mRNA expression was detected. In conclusion, this ex vivo model offers an opportunity to study the molecular mechanisms underlying certain eye disorders and to test new therapeutic approaches to diminish the effects of oxidative stress.

scholarly journals An ex vivo model to induce early fibrosis-like changes in human precision-cut lung slices

2017 ◽  
Vol 312 (6) ◽  
pp. L896-L902 ◽  
Author(s):  
Hani N. Alsafadi ◽  
Claudia A. Staab-Weijnitz ◽  
Mareike Lehmann ◽  
Michael Lindner ◽  
Britta Peschel ◽  
...  
Keyword(s):  
Growth Factor ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Disease Onset ◽  
Water Soluble ◽  
High Morbidity ◽  
Ex Vivo Model ◽  
Early Fibrosis ◽  
Precision Cut Lung Slices

Idiopathic pulmonary fibrosis (IPF) is a devastating chronic interstitial lung disease (ILD) characterized by lung tissue scarring and high morbidity. Lung epithelial injury, myofibroblast activation, and deranged repair are believed to be key processes involved in disease onset and progression, but the exact molecular mechanisms behind IPF remain unclear. Several drugs have been shown to slow disease progression, but treatments that halt or reverse IPF progression have not been identified. Ex vivo models of human lung have been proposed for drug discovery, one of which is precision-cut lung slices (PCLS). Although PCLS production from IPF explants is possible, IPF explants are rare and typically represent end-stage disease. Here we present a novel model of early fibrosis-like changes in human PCLS derived from patients without ILD/IPF using a combination of profibrotic growth factors and signaling molecules (transforming growth factor-β, tumor necrosis factor-α, platelet-derived growth factor-AB, and lysophosphatidic acid). Fibrotic-like changes of PCLS were qualitatively analyzed by histology and immunofluorescence and quantitatively by water-soluble tetrazolium-1, RT-qPCR, Western blot analysis, and ELISA. PCLS remained viable after 5 days of treatment, and fibrotic gene expression ( FN1, SERPINE1, COL1A1, CTGF, MMP7, and ACTA2) increased as early as 24 h of treatment, with increases in protein levels at 48 h and increased deposition of extracellular matrix. Alveolar epithelium reprogramming was evident by decreases in surfactant protein C and loss of HOPX. In summary, using human-derived PCLS, we established a novel ex vivo model that displays characteristics of early fibrosis and could be used to evaluate novel therapies and study early-stage IPF pathomechanisms.

scholarly journals KEAP1, a cysteine-based sensor and a drug target for the prevention and treatment of chronic disease

Open Biology ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 200105 ◽  
Author(s):  
Sharadha Dayalan Naidu ◽  
Albena T. Dinkova-Kostova
Keyword(s):  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Inflammatory Responses ◽  
Redox Homeostasis ◽  
Redox Balance ◽  
Related Factor ◽  
Redox Imbalance ◽  
Persistent Inflammation ◽  
Activation Of Transcription

Redox imbalance and persistent inflammation are the underlying causes of most chronic diseases. Mammalian cells have evolved elaborate mechanisms for restoring redox homeostasis and resolving acute inflammatory responses. One prominent mechanism is that of inducing the expression of antioxidant, anti-inflammatory and other cytoprotective proteins, while also suppressing the production of pro-inflammatory mediators, through the activation of transcription factor nuclear factor-erythroid 2 p45-related factor 2 (NRF2). At homeostatic conditions, NRF2 is a short-lived protein, which avidly binds to Kelch-like ECH-associated protein 1 (KEAP1). KEAP1 functions as (i) a substrate adaptor for a Cullin 3 (CUL3)-based E3 ubiquitin ligase that targets NRF2 for ubiquitination and proteasomal degradation, and (ii) a cysteine-based sensor for a myriad of physiological and pharmacological NRF2 activators. Here, we review the intricate molecular mechanisms by which KEAP1 senses electrophiles and oxidants. Chemical modification of specific cysteine sensors of KEAP1 results in loss of NRF2-repressor function and alterations in the expression of NRF2-target genes that encode large networks of diverse proteins, which collectively restore redox balance and resolve inflammation, thus ensuring a comprehensive cytoprotection. We focus on the cyclic cyanoenones, the most potent NRF2 activators, some of which are currently in clinical trials for various pathologies characterized by redox imbalance and inflammation.

scholarly journals Potential role of lactoferrin in early diagnostics and treatment of Parkinson disease

2020 ◽  
Vol 20 (1) ◽  
pp. 37-44
Author(s):  
Alexey V. Sokolov ◽  
Irina V. Miliukhina ◽  
Yury P. Belsky ◽  
Nataly V. Belska ◽  
Vadim B. Vasilyev
Keyword(s):  
Early Diagnosis ◽  
Substantia Nigra ◽  
Parkinson Disease ◽  
Dopaminergic Neurons ◽  
Experimental Models ◽  
Control Group ◽  
Clear Understanding ◽  
Necrosis Factor Alpha ◽  
Positive Effects ◽  
Factor Alpha

Incidence of Parkinson disease progressively grows with increasing age and percentage of elderly people in the global population. Clear understanding of the causes of dopaminergic neurons death in Substantia nigra and Parkinson disease pathogenesis are currently absent, not speaking of an efficient therapy. However, an early diagnosis of dopaminergic neurons degeneration and prescription of dopamine replacement therapy significantly slow down the rate of symptoms progression. An increased concentration of iron in Substantia nigra of Parkinson disease patients has been shown in several studies. In this review we summarized the data concerning a potential significance of lactoferrin, the iron-binding protein of exocrine secretions and neutrophils, for early diagnosis and treatment of Parkinson disease. Salivary and lacrimal lactoferrin levels in Parkinson disease patients were higher than those observed in the control group. Plasma levels of lactoferrin inversely correlated with Parkinson disease severity even after treatment with Levodopa, a dopamine agonist, and with monoaminooxidase inhibitors. Lactoferrin levels in cerebrospinal fluid of Parkinson disease patients negatively correlated with the tumor necrosis factor-alpha concentration. Lactoferrin treatment of rodents with several experimental models of Parkinson disease (induced by rotenone, MPTP) protected neurons and mitigated the symptoms of neurodegeneration. Some contradictions about the positive effects of lactoferrin as a remedy in Parkinson disease animal models and possible participation of lactoferrin in accumulation of iron in neurons are discussed.

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