Transcriptomic insights into multiple system atrophy from a PLP-α-synuclein transgenic mouse model

Multiple system atrophy (MSA) is a rare, neurodegenerative disorder with rapid motor and non-motor symptom progression. MSA is characterized by protein aggregations of α-synuclein found in the cytoplasm of oligodendrocytes. Despite this pathological hallmark, there is still little known about the cause of this disease, resulting in poor treatment options and quality of life post-diagnosis. In this study, we investigated differentially expressed genes (DEGs) via RNA-sequencing of brain samples from a validated PLP-α-synuclein transgenic mouse model, identifying a total of 40 DEGs in the PLP group compared to wild-type (WT), with top detected genes being Gm15446, Mcm6, Aldh7a1 and Gm3435. We observed a significant enrichment of immune pathways and endothelial cell genes among the upregulated genes, whereas downregulated genes were significantly enriched for oligodendrocyte and neuronal genes. We then calculated possible overlap of these DEGs with previously profiled human MSA RNA, resulting in the identification of significant downregulation of the Tsr2 gene. Identifying key gene expression profiles specific to MSA patients is crucial to further understanding the cause, and possible prevention, of this rapidly progressive neurodegenerative disorder.

Signs of early cellular dysfunction in multiple system atrophy

Aims

Multiple system atrophy (MSA) is a fatal neurodegenerative disease that belongs to the family of α‐synucleinopathies. At post mortem examination, intracellular inclusions of misfolded α‐synuclein are found in neurons and oligodendrocytes and are considered to play a significant role in the pathogenesis. However, the early steps of the disease process are unknown and difficult to study in tissue derived from end‐stage disease.

Methods

Induced pluripotent stem cells (iPSCs) were generated from patients’ and control skin fibroblasts and differentiated into NCAM‐positive neural progenitor cells (NPCs). The mitochondrial morphology and function were assessed by immunocytochemistry and high resolution respirometry. The ability to cope with exogenous oxidative stress was tested by exposure to different doses of luperox. The expression of α‐synuclein was studied by immunocytochemistry.

Results

We identified increased tubulation of mitochondria with preserved respiration profile in MSA‐derived NPCs. Exposure of these cells to exogenous oxidative stress even at low doses, triggered an excessive generation of reactive oxygen species (ROS) and cleavage of caspase‐3. MSA‐derived NPCs did not present changed levels of SNCA gene expression nor intracellular aggregates of α‐synuclein. However, we identified disease‐related translocation of α‐synuclein to the nucleus.

Conclusions

Our results show early cellular dysfunction in MSA‐derived NPCs. We identified changes in the redox homeostasis which are functionally compensated at baseline but cause increased susceptibility to exogenous oxidative stress. In addition, nuclear translocation of α‐synuclein in MSA‐derived NPCs supports an early cellular stress response which may precede the neurodegenerative process in this disorder.

Characteristic of a force sensing guide wire for minimally invasive cardiac surgery

In minimal invasive cardiac surgery (MICS), the surgeon is missing haptic feedback of the guide wire for navigation through the vessels. A wide range of guide wires with various properties and performance characteristics are available to reduce the risk of complications during the intervention. This paper presents a force sensing guide wire for cardiac catheterization, which provides the surgeon a haptic feedback on the guide wire tip. Three conventional wires for the recanalization of chronic total coronary occlusions (CTO) are investigated and general design requirements for the force sensing guide wire are determined. A comparison of the developed with the conventional guide wires concerning the tip force is conducted. The measured tip force of the force sensing guide wire is 50 mN, which is slightly lower than two of the compared conventional wires. As a result, the guide wire offers a good compromise between a soft, low-traumatic and hard guide wire tip.

Review: Multiple system atrophy: emerging targets for interventional therapies

Multiple system atrophy (MSA) is a fatal orphan neurodegenerative disorder that manifests with rapidly progressive autonomic and motor dysfunction. The disease is characterized by the accumulation of α-synuclein fibrils in oligodendrocytes that form glial cytoplasmic inclusions, a neuropathological hallmark and central player in the pathogenesis of MSA. Here, we summarize the current knowledge on the etiopathogenesis and neuropathology of MSA. We discuss the role of α-synuclein pathology, microglial activation, oligodendroglial dysfunction and putative cell death mechanisms as candidate therapeutic targets in MSA.

Cell proliferation in in vivo-like three-dimensional cell culture is regulated by sequestration of ERK1/2 to lipid rafts

OBJECTIVES

Regulatory mechanisms of cell proliferation have been extensively studied as they represent major challenges when dealing with pathologies such as fibrosis, tumourigenesis or tissue regeneration. Numerous in vitro studies still exploit conventional, two-dimensional cell cultures where cells are forced to adhere to unnaturally stiff and flat surfaces of culture dishes. In the living organism, however, each cell is in contact with components of the extracellular matrix and/or neighbouring cells, thus creating a complex three-dimensional (3D) tissue structure. The current paper describes a native 3D culture of cells, based on the GD25β1 fibroblast cell line, and its use for investigating cell proliferation in in vivo-like conditions.

MATERIALS AND METHODS

Four-day post-confluent culture of GD25β1 fibroblasts resulted in formation of a 3D system of cells embedded in naturally synthesized extracellular matrix. Morphological characterization of the culture was performed by histochemistry, immunohistochemistry and immunofluorescence. Viability/proliferation was assayed by MTT testing, FACS analysis and Western blotting for determination of expression levels and activation status of the relevant signalling molecules.

RESULTS

GD25b1 fibroblasts, grown as 3D culture, gave rise to tissue-like structures characterized by low level of apoptosis, low senescence and development of 3D matrix adhesions, typical of living tissues. Transition to three-dimensionality led to a switch from exponential to linear culture growth, accompanied by accumulation of activated ERK1/2 into caveolin-containing raft domains. Disruption of raft domains as well as reverse transition from 3D back to monolayer culture led to release of phosphorylated ERK1/2 from rafts, activation of cyclin D1 expression and increase in proliferation levels.

CONCLUSIONS

These results imply that under in vivo-like conditions, cells might achieve reduction of their proliferation level by sequestering activated ERK1/2 to lipid rafts.

Riluzole improves motor deficits and attenuates loss of striatal neurons in a sequential double lesion rat model of striatonigral degeneration (parkinson variant of multiple system atrophy)

We investigated neuroprotective effects of riluzole, an anti-glutamatergic agent that is FDA approved for disease-modifying therapy in amyotrophic lateral sclerosis (ALS), in an established double lesion rat model of striatonigral degeneration (SND), the neuropathological substrate of parkinsonism associated with MSA (MSA-P). Riluzole was administered prior to and consecutively for ten days following double lesion placement in the left-sided medial forebrain bundle and ipsilateral striatum. Assessment of motor behaviour using a flex field system showed a significant reduction of motor disturbance in animals with striatonigral lesions treated with riluzole compared to lesioned but untreated animals (P<0.001). DARPP-32 immunohistochemistry revealed a significant reduction of absolute striatal lesion volume in riluzole treated animals compared to lesioned but untreated animals (P<0.01). No significant difference in counts of nigral dopaminergic neurons was found in treated versus untreated double-lesioned animals. The results of our study indicate that riluzole mediates neuroprotective effects in the double lesion rat model of MSA-P. Whether riluzole also protects autonomic and cerebellar pathways that are frequently affected in MSA remains to be determined. Nonetheless, our study is the first to provide an experimental rationale for exploring possible neuroprotective effects of riluzole in MSA.

Effects of pulsatile L-DOPA treatment in the double lesion rat model of striatonigral degeneration (multiple system atrophy)

We examined the role of a striatal lesion in the development of L-DOPA-induced abnormal involuntary movements (AIMs) using the double lesion rat model of striatonigral degeneration (SND), the underlying neuropathological substrate of parkinsonism associated with multiple system atrophy (MSA-P), in comparison to a Parkinson's disease (PD) rat model. L-DOPA administration reliably induced AIMs in SND and PD rats in a dose-dependent fashion. AIMs occurred significantly earlier in SND compared to PD rats. There was a mild, but significant, transient increase of orolingual AIMs during the first week of low-dose L-DOPA treatment in SND. Whereas L-DOPA significantly improved contralateral forelimb akinesia in PD rats, there was no beneficial effect in SND rats. Striatal FosB/Delta FosB up-regulation in SND and PD rats correlated with the severity of L-DOPA-induced dyskinesias. Pulsatile L-DOPA administration in the double lesion SND rat model replicates salient features of the human disease MSA-P, including loss of the anti-akinetic L-DOPA response and induction of dyskinesias with transient orolingual predominance.

Subacute systemic 3-nitropropionic acid intoxication induces a distinct motor disorder in adult C57Bl/6 mice: behavioural and histopathological characterisation

Data on motor behavioural disorders induced by systemic 3-nitropropionic acid, an irreversible inhibitor of mitochondrial succinate dehydrogenase and their histopathological correlates in mice, are sparse. We thus further characterised the subacute 3-nitropropionic-acid-induced motor disorder and its time course in C57Bl/6 mice using standard behavioural tests, histopathological correlates and in vivo magnetic resonance imaging. Firstly, we studied two intoxication paradigms (340 and 560 mg 3-nitropropionic acid/kg, 7 days) compared to controls. The low-dose regimen induced only slight motor changes (reduced hindlimb stride length and rearing). The high-dose regimen induced significant (P<0.05) behavioural and sensorimotor integration deficits (pole test, rotarod, stride length, open-field spontaneous activity) but with 37.5% lethality at week one. The clinical motor disorder consisted of hindlimb clasping and dystonia, truncal dystonia, bradykinesia and impaired postural control. Histopathologically, there were discrete lesions of the dorsolateral striatum in 62.5% of mice together with a 32% reduction (P<0.0001) of the striatal volume, reduced caldbindin-D28K immunoreactivity in the lateral striatum, and met-enkephalin and substance P in the striatal output pathways. There was also a significant (P<0.05) 30-40% dopaminergic cell loss within the substantia nigra pars compacta. Secondly, we validated a semi-quantitative behavioural scale to describe the time course of the motor deficits and to predict the occurrence of striatal damage. We sought to determine whether it could also be disclosed in vivo by magnetic resonance imaging. The scale correlated with the striatal volume reduction (r(2)=0.57) and striatal cell loss (r(2)=0.87) but not with the loss of striatal dopaminergic terminals (dopamine transporter binding). Increased T2-signal intensity within the striatal lesion correlated with the cell loss (r(2)=0.66). We conclude that systemic administration of 3-nitropropionic acid in C57Bl/6 mice induces a distinct motor disorder and dose-dependent striatonigral damage, which are potentially useful to model human diseases of the basal ganglia.

Dystonia is predictive of subsequent altered dopaminergic responsiveness in a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine+3-nitropropionic acid model of striatonigral degeneration in monkeys

We conducted a new chronic sequential 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 3-nitropropionic acid (3NP) intoxication paradigm in two female monkeys in order to reproduce the striatonigral degeneration type of levodopa-unresponsive parkinsonism. A comparison was made with MPTP-, 3NP-intoxicated and control monkeys. A levodopa-responsive parkinsonism emerged in all MPTP-treated monkeys. During subsequent 3NP intoxication, one of the two MPTP +3NP monkeys exhibited hindlimb dystonia concomitantly with a reduced levodopa response. All MPTP-monkeys had severe cell loss in the substantia nigra pars compacta (>70%), but 3NP-induced discrete lesioned areas and cell loss predominantly in the putamen appeared only in the dystonic and levodopa-unresponsive animal. We propose that the appearance of dystonia after 3NP intoxication following dopaminergic striatal denervation is the key symptom predictive of the loss of dopaminergic response.

Ultrastructure of alpha-synuclein-positive aggregations in U373 astrocytoma and rat primary glial cells

Abnormal alpha-synuclein-positive glial cytoplasmic inclusions are found in Parkinson's disease, multiple system atrophy and dementia with Lewy bodies. We have recently developed an in vitro model of alpha-synuclein-immunoreactive aggregations in U373 astrocytoma cells. We have additionally overexpressed wild-type and a C-terminally truncated form of alpha-synuclein in primary rat glial cells. Astrocytes and oligodendrocytes were found to form alpha-synuclein-positive aggregations in vitro perinuclearly or in the processes of the cells. The morphological studies presented here demonstrate that the aggregations we have observed in vitro are not limited by a membrane but have unclear borders. They have an amorphous dense core that is intensely alpha-synuclein-immunopositive and a predominantly filamentous halo around. Mainly filamentous structures at the border area between the halo and the core are alpha-synuclein-immunoreactive. We conclude that this in vitro model of alpha-synuclein-positive glial aggregations mimics the morphology of the abnormal glial inclusions described in neurodegenerative disorders and could be a suitable model for studying their role in the pathogenesis of these diseases.

Multiple system atrophy

Multiple system atrophy (MSA) is an adult-onset sporadic progressive neurodegenerative disorder of unknown etiology. It is clinically characterized by the variable combination of autonomic failure, parkinsonism, cerebellar ataxia, and pyramidal signs. The present review summarizes up-to-date knowledge on the clinical diagnosis and molecular pathology of MSA. We also review the role of additional investigations that may support a clinical diagnosis of MSA. Finally, we briefly discuss the management of MSA, focusing on possible future therapeutic strategies.

Glial cell death induced by overexpression of alpha-synuclein

alpha-Synuclein is present in intracellular protein aggregates that are hallmarks of common neurodegenerative disorders including Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. alpha-Synuclein is localized in neurons and presynaptic terminals. Under pathological conditions, however, it is also found in glia. The role of alpha-synuclein in glial cells and its relevance to the molecular pathology of neurodegenerative diseases is presently unclear. To investigate the consequence of alpha-synuclein overexpression in glia, we transfected U373 astrocytoma cells with vectors encoding wild-type human alpha-synuclein or C-terminally truncated synuclein fused to red fluorescent protein. alpha-synuclein immunocytochemistry of transfected astroglial cells revealed diffuse cytoplasmic labeling associated with discrete inclusions both within cell bodies and processes. Susceptibility to oxidative stress was increased in astroglial cells overexpressing alpha-synuclein, particularly in the presence of cytoplasmic inclusions. Furthermore, overexpression of alpha-synuclein induced apoptotic death of astroglial cells as shown by TUNEL staining. Our in vitro model is the first to replicate salient features of the glial pathology associated with alpha-synucleinopathies. It provides a simple testbed to further explore the cascade of events that leads to apoptotic glial cell death in some of these disorders; it may also be useful to assess the effects of therapeutic interventions including antioxidative and antiapoptotic strategies.

The predictability of inferior medial canthus as a stable external vertical reference point in maxillary repositioning surgery

The purpose of this study was to investigate the predictability of using the inferior medial canthus as a stable external reference point for establishment of the vertical dimension in maxillary orthognathic surgery. Ten consecutive patients with skeletal Class II malocclusion and open bite who underwent orthognathic reconstructive surgery were included in the study. Prediction tracings were completed preoperatively and superimposed on an immediate postoperative lateral cephalometric radiograph. In 7 patients, the vertical positioning of the maxillary incisal edge on the immediate postoperative lateral cephalometric radiograph showed no difference from the superimposed preoperative prediction tracing. One patient showed 1 mm difference and 2 patients showed 2 mm difference from the preoperative prediction tracings. All cases resulted in acceptable maxillary incisal exposure relative to upper lip stomion. It is concluded that the inferior medial canthus can be used as a reproducible external vertical reference for orthognathic surgery when the technique described herein is used.

Predictability of bimaxillary orthognathic surgery using "piggyback" intermediate splints

Ten consecutive patients underwent bimaxillary surgery including segmental Le Fort I and bilateral sagittal split ramus osteotomies. All 10 patients were symmetric skeletal Class II malocclusion with an anterior open bite. Asymmetry cases were excluded. Dimensional changes depicted on the cephalometric prediction tracing were reproduced in the model surgery and then transferred to the patient during the operative procedure using a "piggyback" intermediate splint. All dimensional changes, except vertical, were transferred from the model surgery to the patient intraoperatively by using a "piggyback" intermediate splint. The accuracy of this transfer and final skeletal result was examined. All the data clearly showed that in no case was any discrepancy greater than 2 mm, which demonstrates the predictable results that can be achieved by using a "piggyback" intermediate splint in bimaxillary orthognathic surgery.

Depression in alpha-synucleinopathies: prevalence, pathophysiology and treatment

Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA) are increasingly recognized as alpha-synucleinopathies, i.e. neurodegenerative disorders that share a common subcellular pathology characterized by alpha-synuclein abnormal aggregation. In the present review we focus on depression in alpha-synucleinopathies, discussing epidemiological, pathophysiological and treatment aspects of this frequently disabling clinical feature which may occur in PD, DLB and MSA alike.

Sexual dimorphism of the bed nucleus of the stria terminalis and the amygdala

The present review summarizes the up-to-date knowledge on the sexual dimorphism of the CNS with special regard to the sexual differentiation of the bed nucleus of the stria terminalis (BST) and the amygdala in rat. The authors provide new evidence for the sexual dimorphism and differentiation of GABAergic, leucine-enkephalin-containing and parvalbumin-immunoreactive neurons in the BST and the amygdala of the rat. Together with testing the gender differences, age-related changes in numbers of the neuronal subpopulations, mentioned above are followed. The authors' results provide morphological and immunocytochemical data that may be used for further studies on sexually dimorphic circuitry and its functional significance.

Failure of neuroprotection by embryonic striatal grafts in a double lesion rat model of striatonigral degeneration (multiple system atrophy)

In the present experiment we studied the ability of embryonic striatal grafts to protect against striatal quinolinic acid (QA)-induced excitotoxicity in a previously established double lesion rat model of striatonigral degeneration (SND), the neuropathological substrate of parkinsonism associated with multiple system atrophy (MSA). Male Wistar rats received under halothane inhalation anesthesia a 6-hydroxydopamine 6-OHDA injection into the left medial forebrain bundle. Four to 5 weeks later apomorphine-induced rotation behavior was tested. Rats were divided into two treatment groups receiving either embryonic striatal cell suspensions or sham injections. Apomorphine-induced rotation behavior was retested 2 and 4 weeks after the grafting procedure. Following the rotation test animals of the striatal and sham graft group received a stereotaxic injection of 150 nmol QA. Again rotation behavior was assessed 2 and 4 weeks after lesioning. Brains were then processed to dopamine reuptake ([(3)H]mazindol), dopamine D1 ([(3)H]SCH23390), and D2 ([(3)H]spiperone) receptor autoradiography. Gliosis was detected using [(3)H]PK11195, a marker for peripheral benzodiazepine binding sites. Behavioral and autoradiographic analysis failed to show striatal protection in 6-OHDA prelesioned animals receiving embryonic striatal grafts. These findings indicate that beneficial protective effects of striatal grafts implanted into host striatum prior to excitotoxic insults are abolished in the presence of severe dopaminergic denervation. Our present results are relevant to future applications of neural grafting in MSA-SND.

Geometric considerations when planning an asymmetric genioplasty

The sliding osteotomy of the inferior border of the mandible, otherwise known as genioplasty, has often been described in the world literature with regard to diagnosis and treatment planning. However, the treatment of the asymmetric chin has received little attention. Moreover, diagnosis and treatment planning of asymmetric chins with concomitant orthognathic surgery is completely lacking from the literature. The complexity of surgically correcting asymmetric chins, compounded with complex, bimaxillary orthognathic surgery, is an extremely challenging task. This article looks at geometric considerations when planning the surgical correction of an asymmetric chin following a protocol of data collection, model surgery, diagnosis, and treatment planning. Clinical experience in the form of a case presentation will demonstrate the millimetric precision that can be achieved when planning corrective genioplasty in an asymmetric patient undergoing concomitant orthognathic surgery.

Gamma-aminobutyric acid-immunoreactive neurons in the amygdala of the rat - sex differences and effect of early postnatal castration

The distribution of GABA-immunoreactive neurons in the rat amygdala was determined by immunohistochemical methods. Sex differences in the number of GABA-immunoreactive cell bodies were observed in the medial, central, cortical and basolateral amygdaloid nuclei. Females had more numerous GABA-expressing neurons than males (P < 0.01). Castration of neonatal males had controversial effects on this sex difference in the different parts of the amygdaloid complex. In the cortical and basolateral amygdala castrated males showed a female pattern of GABA-expression. In the central amygdala no effect of castration on the number of GABA-immunoreactive cells was found. In the medial amygdaloid nucleus numbers of GABAergic neurons in castrated males differed both from intact males and females. The results of the present study suggest that the expression of GABA in the neurons of the amygdala is under complicated gonadal hormone regulation.

Sex and age differences of neurons expressing GABA-immunoreactivity in the rat bed nucleus of the stria terminalis

Neurons, containing GABA were visualised immunohistochemically in the bed nucleus of the stria terminalis. Young prepubertal (20 days of age) and postpubertal (3 months and 1 year of age) Sprague-Dawley rats were used. Quantitative studies revealed greater density of GABA-immunoreactive perikarya in female than in male bed nucleus of the stria terminalis. This difference was not due to distribution in different volumes, since the volumes of the bed nucleus of the stria terminalis in the three ages studied did not differ by gender. Castration of new-born male rats caused elevation of the density of GABA-immunoreactive neurons in the bed nucleus of the stria terminalis to female levels on the third month of life. The percentage of nerve cells, expressing detectable amounts of GABA increased with age in the rat bed nucleus of the stria terminalis. The sexual dimorphism of GABA-immunoreactive neurons in the bed nucleus of the stria terminalis may contribute to the formation of reproductive behavior. The elevation of GABA expression with age might reflect change of the cellular activity in this part of the limbic circuitry.

Distribution of GABA-immunoreactive nerve cells in the bed nucleus of the stria terminalis in male and female rats

The distribution of GABA-immunoreactive neurons in the subnuclei of the rat bed nucleus of the stria terminalis (BST) was studied by means of GABA immunohistochemistry. For detection of GABA immunoreactivity we used polyclonal antibodies and silver intensification. We have compared the pattern of distribution of immunoreactive cells in male and female rats and found some sexual difference, that may underlie functional variety. Computer assisted quantitative analysis of GABA-immunoreactive neurons per mm2 showed statistically significant sex differences in the medial part of the BST (0.001 < P < 0.01). The difference in the BST as a whole was set at 0.05 < P < 0.1. Females had more numerous GABA-immunoreactive cells than males. The measuring of sex differences was done using double-tailed Student's t-test after submitting the data to ANOVA.