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1.
Eur J Hum Genet ; 2024 Jan 23.
Article in English | MEDLINE | ID: mdl-38253783

ABSTRACT

The inherited disease community in Sri Lanka has been widely neglected. This article aimed to present accumulated knowledge in establishing a pro bono cost-effective national, island-wide, free-of-charge molecular diagnostic service, suggesting a model for other developing countries. The project provided 637 molecular diagnostic tests and reports free of charge to a nation with limited resources. We pioneered the implementation of mobile clinics and home visits, where the research team acted as barefoot doctors with the concept of the doctor and the researcher at the patient's doorstep. Establishing pro bono, cost-effective molecular diagnostics is feasible in developing countries with limited resources and state funding through the effort of dedicated postgraduate students. This service could provide an accurate molecular diagnosis of Duchenne muscular dystrophy, Huntington's disease, Spinocerebellar ataxia, and Spinal muscular atrophy, a diagnostic yield of 54% (343/637), of which 43% (147/343) of the patients identified as amenable for available gene therapies. Initiated human resource development by double doctoral degree opportunities with international collaborations. Established a neurobiobank and a national registry in Sri Lanka, a rich and unique repository, wealth creation for translational collaborative research and sharing of information in neurological diseases, as well as a lodestar for aspiring initiatives from other developing countries.

2.
Eur J Med Res ; 29(1): 37, 2024 Jan 09.
Article in English | MEDLINE | ID: mdl-38195599

ABSTRACT

BACKGROUND: The phenotype of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) patients is determined by the type of DMD gene variation, its location, effect on reading frame, and its size. The primary objective of this investigation was to determine the frequency and distribution of DMD gene variants (deletions/duplications) in Sri Lanka through the utilization of a combined approach involving multiplex polymerase chain reaction (mPCR) followed by Multiplex Ligation Dependent Probe Amplification (MLPA) and compare to the international literature. The current consensus is that MLPA is a labor efficient yet expensive technique for identifying deletions and duplications in the DMD gene. METHODOLOGY: Genetic analysis was performed in a cohort of 236 clinically suspected pediatric and adult myopathy patients in Sri Lanka, using mPCR and MLPA. A comparative analysis was conducted between our findings and literature data. RESULTS: In the entire patient cohort (n = 236), mPCR solely was able to identify deletions in the DMD gene in 131/236 patients (DMD-120, BMD-11). In the same cohort, MLPA confirmed deletions in 149/236 patients [DMD-138, BMD -11]. These findings suggest that mPCR has a detection rate of 95% (131/138) among all patients who received a diagnosis. The distal and proximal deletion hotspots for DMD were exons 45-55 and 6-15. Exon 45-60 identified as a novel in-frame variation hotspot. Exon 45-59 was a hotspot for BMD deletions. Comparisons with the international literature show significant variations observed in deletion and duplication frequencies in DMD gene across different populations. CONCLUSION: DMD gene deletions and duplications are concentrated in exons 45-55 and 2-20 respectively, which match global variation hotspots. Disparities in deletion and duplication frequencies were observed when comparing our data to other Asian and Western populations. Identified a 95% deletion detection rate for mPCR, making it a viable initial molecular diagnostic approach for low-resource countries where MLPA could be used to evaluate negative mPCR cases and cases with ambiguous mutation borders. Our findings may have important implications in the early identification of DMD with limited resources in Sri Lanka and to develop tailored molecular diagnostic algorithms that are regional and population specific and easily implemented in resource limited settings.


Subject(s)
Pathology, Molecular , Resource-Limited Settings , Adult , Humans , Child , Sri Lanka , Algorithms , Phenotype
3.
J Neurosci Rural Pract ; 14(4): 637-643, 2023.
Article in English | MEDLINE | ID: mdl-38059224

ABSTRACT

Objectives: Pain is common after craniotomy. Its incidence and predictors in developing nations are not adequately studied. We aimed to assess the incidence, predictors, and impact of acute post-operative pain after intracranial neurosurgeries. Materials and Methods: This prospective observational study was conducted in adult patients undergoing intracranial neurosurgeries. After patient consent, ethics committee approval, and study registration, we assessed the incidence of post-operative pain using numerical rating scale (NRS) score. Predictors and impact of pain on patient outcomes were also evaluated. Results: A total of 497 patients were recruited during 10-month study period. Significant (4-10 NRS score) post-operative pain at any time-point during the first 3 days after intracranial neurosurgery was reported by 65.5% (307/469) of patients. Incidence of significant pain during the 1st post-operative h, on the 1st, 2nd, and 3rd post-operative days was 20% (78/391), 50% (209/418), 38% (152/401), and 24% (86/360), respectively. Higher pre-operative NRS score and pain during the 1st h post-operatively, predicted the occurrence of pain during the first 3 days after surgery, P = 0.003 and P < 0.001, respectively. Pain was significantly associated with poor sleep quality on the first 2 post-operative nights (P < 0.001). Patient satisfaction score was higher in patients with post-operative pain, P = 0.002. Conclusion: Every two in three patients undergoing elective intracranial neurosurgery report significant pain at some point during the first 3 postoperative days. Pre-operative pain and pain during 1st post-operative h predict the occurrence of significant post-operative pain.

4.
J Clin Med ; 12(17)2023 Aug 29.
Article in English | MEDLINE | ID: mdl-37685704

ABSTRACT

Brain function and its effect on motor performance in Duchenne muscular dystrophy (DMD) is an emerging concept. The present study explored how cumulative dystrophin isoform loss, age, and a corticosteroid treatment affect DMD motor outcomes. A total of 133 genetically confirmed DMD patients from Sri Lanka were divided into two groups based on whether their shorter dystrophin isoforms (Dp140, Dp116, and Dp71) were affected: Group 1, containing patients with Dp140, Dp116, and Dp71 affected (n = 98), and Group 2, containing unaffected patients (n = 35). A subset of 52 patients (Group 1, n = 38; Group 2, n = 14) was followed for up to three follow-ups performed in an average of 28-month intervals. The effect of the cumulative loss of shorter dystrophin isoforms on the natural history of DMD was analyzed. A total of 74/133 (56%) patients encountered developmental delays, with 66/74 (89%) being in Group 1 and 8/74 (11%) being in Group 2 (p < 0.001). Motor developmental delays were predominant. The hip and knee muscular strength, according to the Medical Research Council (MRC) scale and the North Star Ambulatory Assessment (NSAA) activities, "standing on one leg R", "standing on one leg L", and "walk", declined rapidly in Group 1 (p < 0.001 In the follow-up analysis, Group 1 patients became wheelchair-bound at a younger age than those of Group 2 (p = 0.004). DMD motor dysfunction is linked to DMD mutations that affect shorter dystrophin isoforms. When stratifying individuals for clinical trials, considering the DMD mutation site and its impact on a shorter dystrophin isoform is crucial.

5.
Heliyon ; 9(8): e18530, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37593636

ABSTRACT

Introduction: Documented Duchenne Muscular Dystrophy (DMD) biomarkers are confined to Caucasians and are poor indicators of cognitive difficulties and neuropsychological alterations. Materials and methods: This study correlates serum protein signatures with cognitive performance in DMD patients of South Asian origin. Study included 25 DMD patients aged 6-16 years. Cognitive profiles were assessed by Wechsler Intelligence Scale for Children. Serum proteome profiling of 1317 proteins was performed in eight DMD patients and eight age-matched healthy volunteers. Results: Among the several novel observations we report, better cognitive performance in DMD was associated with increased serum levels of MMP9 and FN1 but decreased Siglec-3, C4b, and C3b. Worse cognitive performance was associated with increased serum levels of LDH-H1 and PDGF-BB but reduced GDF-11, MMP12, TPSB2, and G1B. Secondly, better cognitive performance in Processing Speed (PSI) and Perceptual Reasoning (PRI) domains was associated with intact Dp116, Dp140, and Dp71 dystrophin isoforms while better performance in Verbal Comprehension (VCI) and Working Memory (WMI) domains was associated with intact Dp116 and Dp140 isoforms. Finally, functional pathways shared with Alzheimer's Disease (AD) point towards an astrocyte-centric model for DMD. Conclusion: Astrocytic dysfunction leading to synaptic dysfunction reported previously in AD may be a common pathogenic mechanism underlying both AD and DMD, linking protein alterations to cognitive impairment. This new insight may pave the path towards novel therapeutic approaches targeting reactive astrocytes.

6.
IBRO Neurosci Rep ; 14: 146-153, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36819775

ABSTRACT

Background: In this article, the authors discuss how they utilized the genetic mutation data in Sri Lankan Duchenne muscular dystrophy (DMD), Spinal muscular atrophy (SMA), Spinocerebellar ataxia (SCA) and Huntington's disease (HD) patients and compare the available literature from South Asian countries to identifying potential candidates for available gene therapy for DMD, SMA, SCA and HD patients. Methods: Rare disease patients (n = 623) with the characteristic clinical findings suspected of HD, SCA, SMA and Muscular Dystrophy were genetically confirmed using Multiplex Ligation Dependent Probe Amplification (MLPA), and single plex PCR. A survey was conducted in the "Wiley database on Gene Therapy Trials Worldwide" to identify DMD, SMA, SCA, and HD gene therapy clinical trials performed worldwide up to April 2021. In order to identify candidates for gene therapy in other neighboring countries we compared our findings with available literature from India and Pakistan which has utilized the same molecular diagnostic protocol to our study. Results: From the overall cohort of 623 rare disease patients with the characteristic clinical findings suspected of HD, SCA, SMA and Muscular Dystrophy, n = 343 (55%) [Muscular Dystrophy- 65%; (DMD-139, Becker Muscular Dystrophy -BMD-11), SCA type 1-3-53% (SCA1-61,SCA2- 23, SCA3- 39), HD- 52% (45) and SMA- 34% (22)] patients were positive for molecular diagnostics by MLPA and single plex PCR. A total of 147 patients in Sri Lanka amenable to available gene therapy; [DMD-83, SMA-15 and HD-49] were identified. A comparison of Sri Lankan finding with available literature from India and Pakistan identified a total of 1257 patients [DMD-1076, SMA- 57, and HD-124] from these three South Asian Countries as amenable for existing gene therapy trials. DMD, SMA, and HD gene therapy clinical trials (113 studies) performed worldwide up to April 2021 were concentrated mostly (99%) in High Income Countries (HIC) and Upper Middle-Income Countries (UMIC). However, studies on the potential use of anti-sense oligonucleotides (ASO) for treatment of SCAs have yet to reach clinical trials. Conclusion: Most genetic therapies for neurodegenerative and neuromuscular disorders have been evaluated for efficacy primarily in Western populations. No multicenter gene therapy clinical trial sites for DMD, SMA and HD in the South Asian region, leading to lack of knowledge on the safety and efficacy of such personalized therapies in other populations, including South Asians. By fostering collaboration between researchers, clinicians, patient advocacy groups, government and industry in gene therapy initiatives for the inherited-diseases community in the developing world would link the Global North and Global South and breathe life into the motto "Together we can make a difference".

8.
Behav Brain Res ; 439: 114220, 2023 02 15.
Article in English | MEDLINE | ID: mdl-36414104

ABSTRACT

Excessively released proinflammatory mediators from activated macrophages and lymphocytes may contribute to the etiology of depression. However, the relationship between lymphocytes and depression is not fully understood. Although women have higher depression risk than men, sex/gender differences in psychoneuroimmunological mechanisms are still unclear. To explore these two questions, chronic unpredictable mild stress (CUMS) was used to evaluate the changes in behaviors, inflammation and lymphocyte subtypes in adult male and female Wistar rats. Results show that CUMS increased anhedonia and anxiety-like behaviors, along with increased serum corticosterone, hippocampal pro-inflammatory factors, CD11b, IFN-γ, IL-6 and IL-17, but decreased CD4, CD25, CD4/CD8 ratio, GFAP, 5-hydroxytryptamine (5-HT) and NE concentrations, regardless of sex. There was no positive correlation between sucrose preference and blood CD4/CD8 ratio, but a positive correlation between sucrose preference and spleen CD25, sucrose preference and neurotransmitters (NE and 5-HT), spleen CD25 and serum TGF-ß1/IL-6 ratio were found, regardless of sex. Females presented higher basal locomotion, blood CD4, CD4/CD8 ratio, serum corticosteroid and IL-6 concentrations, but lower hippocampal norepinephrine (NE) than males. Although CUMS didn't induce significant sex differences, females presented more changes in CD4 and CD8 lymphocytes than male rats. CUMS caused abnormalities in corticosteroid, lymphocytes, cytokines and neurotransmitters, which might be the precursors for inducing depression-like behaviors in both sexes.


Subject(s)
Depression , Interleukin-6 , Rats , Female , Male , Animals , Depression/etiology , Rats, Wistar , Serotonin/pharmacology , Inflammation , Hippocampus , Norepinephrine/pharmacology , Sucrose/pharmacology , Lymphocytes , Stress, Psychological , Disease Models, Animal
9.
Brain Pathol ; 32(2): e13033, 2022 03.
Article in English | MEDLINE | ID: mdl-34704631

ABSTRACT

Alzheimer's disease (AD) is the most prevalent form of dementia. Key AD symptoms include memory and cognitive decline; however, comorbid symptoms such as depression and sensory-perceptual dysfunction are often reported. Among these, a deterioration of olfactory sensation is observed in approximately 90% of AD patients. However, the precise pathophysiological basis underlying olfactory deficits because of AD remains elusive. The olfactory glomeruli in the olfactory bulb (OB) receive sensory information in the olfactory processing pathway. Maintaining the structural and functional integrity of the olfactory glomerulus is critical to olfactory signalling. Herein, we conducted an in-depth histopathological assessment to reveal detailed structural alterations in the olfactory glomeruli in AD patients. Fresh frozen post-mortem OB specimens obtained from six AD patients and seven healthy age-matched individuals were examined. We used combined immunohistochemistry and stereology to assess the gross morphology and histological alterations, such as those in the expression of Aß protein, microglia, and neurotransmitters in the OB. Electron microscopy was employed to study the ultrastructural features in the glomeruli. Significant accumulation of Aß, morphologic damage, altered neurotransmitter levels, and microgliosis in the olfactory glomeruli of AD patients suggests that glomerular damage could affect olfactory function. Moreover, greater neurodegeneration was observed in the ventral olfactory glomeruli of AD patients. The synaptic ultrastructure revealed distorted postsynaptic densities and a decline in presynaptic vesicles in AD specimens. These findings show that the primary olfactory pathway is affected by the pathogenesis of AD, and may provide clues to identifying the mechanism involved in olfactory dysfunction in AD.


Subject(s)
Alzheimer Disease , Olfactory Bulb , Alzheimer Disease/pathology , Autopsy , Humans , Olfactory Bulb/metabolism , Smell
10.
Biomedicines ; 9(10)2021 Sep 22.
Article in English | MEDLINE | ID: mdl-34680401

ABSTRACT

Acquiring the recommended daily allowance of vitamins is crucial for maintaining homeostatic balance in humans and other animals. A deficiency in or dysregulation of vitamins adversely affects the neuronal metabolism, which may lead to neurodegenerative diseases. In this article, we discuss how novel vitamin-based approaches aid in attenuating abnormal neuronal functioning in neurodegeneration-based brain diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, and Prion disease. Vitamins show their therapeutic activity in Parkinson's disease by antioxidative and anti-inflammatory activity. In addition, different water- and lipid-soluble vitamins have also prevented amyloid beta and tau pathology. On the other hand, some results also show no correlation between vitamin action and the prevention of neurodegenerative diseases. Some vitamins also exhibit toxic activity too. This review discusses both the beneficial and null effects of vitamin supplementation for neurological disorders. The detailed mechanism of action of both water- and lipid-soluble vitamins is addressed in the manuscript. Hormesis is also an essential factor that is very helpful to determine the effective dose of vitamins. PubMed, Google Scholar, Web of Science, and Scopus were employed to conduct the literature search of original articles, review articles, and meta-analyses.

11.
BMB Rep ; 54(6): 295-304, 2021 Jun.
Article in English | MEDLINE | ID: mdl-34162463

ABSTRACT

Olfactory neuropathology is a cause of olfactory loss in Alzheimer's disease (AD). Olfactory dysfunction is also associated with memory and cognitive dysfunction and is an incidental finding of AD dementia. Here we review neuropathological research on the olfactory system in AD, considering both structural and functional evidence. Experimental and clinical findings identify olfactory dysfunction as an early indicator of AD. In keeping with this, amyloid-ß production and neuroinflammation are related to underlying causes of impaired olfaction. Notably, physiological features of the spatial map in the olfactory system suggest the evidence of ongoing neurodegeneration. Our aim in this review is to examine olfactory pathology findings essential to identifying mechanisms of olfactory dysfunction in the development of AD in hopes of supporting investigations leading towards revealing potential diagnostic methods and causes of early pathogenesis in the olfactory system. [BMB Reports 2021; 54(6): 295-304].


Subject(s)
Alzheimer Disease/complications , Neural Pathways/pathology , Neurodegenerative Diseases/pathology , Olfaction Disorders/pathology , Olfactory Pathways/pathology , Animals , Humans , Neurodegenerative Diseases/etiology , Olfaction Disorders/etiology
12.
Prog Brain Res ; 261: 41-81, 2021.
Article in English | MEDLINE | ID: mdl-33785137

ABSTRACT

The brainstem is a neglected brain area in neurodegenerative diseases, including Alzheimer's and Parkinson's disease, frontotemporal lobar degeneration and autonomic dysfunction. In Depression, several observations have been made in relation to changes in one particular the Dorsal Raphe Nucleus (DRN) which also points toward as key area in various age-related and neurodevelopmental diseases. The DRN is further thought to be related to stress regulated processes and cognitive events. It is involved in neurodegeneration, e.g., amyloid plaques, neurofibrillary tangles, and impaired synaptic transmission in Alzheimer's disease as shown in our autopsy findings. The DRN is a phylogenetically old brain area, with projections that reach out to a large number of regions and nuclei of the central nervous system, particularly in the forebrain. These ascending projections contain multiple neurotransmitters. One of the main reasons for the past and current interest in the DRN is its involvement in depression, and its main transmitter serotonin. The DRN also points toward the increased importance and focus of the brainstem as key area in various age-related and neurodevelopmental diseases. This review describes the morphology, ascending projections and the complex neurotransmitter nature of the DRN, stressing its role as a key research target into the neural bases of depression.


Subject(s)
Dorsal Raphe Nucleus , Alzheimer Disease , Animals , Brain Stem , Humans , Mammals , Neurotransmitter Agents , Serotonin
13.
Alzheimers Res Ther ; 13(1): 4, 2021 01 04.
Article in English | MEDLINE | ID: mdl-33397474

ABSTRACT

BACKGROUND: Hyposmia in Alzheimer's disease (AD) is a typical early symptom according to numerous previous clinical studies. Although amyloid-ß (Aß), which is one of the toxic factors upregulated early in AD, has been identified in many studies, even in the peripheral areas of the olfactory system, the pathology involving olfactory sensory neurons (OSNs) remains poorly understood. METHODS: Here, we focused on peripheral olfactory sensory neurons (OSNs) and delved deeper into the direct relationship between pathophysiological and behavioral results using odorants. We also confirmed histologically the pathological changes in 3-month-old 5xFAD mouse models, which recapitulates AD pathology. We introduced a numeric scale histologically to compare physiological phenomenon and local tissue lesions regardless of the anatomical plane. RESULTS: We observed the odorant group that the 5xFAD mice showed reduced responses to odorants. These also did not physiologically activate OSNs that propagate their axons to the ventral olfactory bulb. Interestingly, the amount of accumulated amyloid-ß (Aß) was high in the OSNs located in the olfactory epithelial ectoturbinate and the ventral olfactory bulb glomeruli. We also observed irreversible damage to the ectoturbinate of the olfactory epithelium by measuring the impaired neuronal turnover ratio from the basal cells to the matured OSNs. CONCLUSIONS: Our results showed that partial and asymmetrical accumulation of Aß coincided with physiologically and structurally damaged areas in the peripheral olfactory system, which evoked hyporeactivity to some odorants. Taken together, partial olfactory dysfunction closely associated with peripheral OSN's loss could be a leading cause of AD-related hyposmia, a characteristic of early AD.


Subject(s)
Olfactory Receptor Neurons , Amyloid beta-Peptides/metabolism , Animals , Axons/metabolism , Mice , Mice, Transgenic , Olfactory Bulb/metabolism , Olfactory Receptor Neurons/metabolism , Smell
14.
Prog Neurobiol ; 198: 101906, 2021 03.
Article in English | MEDLINE | ID: mdl-32905807

ABSTRACT

The dual-specificity phosphatase (DUSP) family includes a heterogeneous group of protein phosphatases that dephosphorylate both phospho-tyrosine and phospho-serine/phospho-threonine residues within a single substrate. These protein phosphatases have many substrates and modulate diverse neural functions, such as neurogenesis, differentiation, and apoptosis. DUSP genes have furthermore been associated with mental disorders such as depression and neurological disorders such as Alzheimer's disease. Herein, we review the current literature on the DUSP family of genes concerning mental and neurological disorders. This review i) outlines the structure and general functions of DUSP genes, and ii) overviews the literature on DUSP genes concerning mental and neurological disorders, including model systems, while furthermore providing perspectives for future research.


Subject(s)
Nervous System Diseases , Dual-Specificity Phosphatases , Humans , Nervous System Diseases/genetics , Neurogenesis , Phosphoprotein Phosphatases
15.
Front Aging Neurosci ; 12: 214, 2020.
Article in English | MEDLINE | ID: mdl-32848701

ABSTRACT

Background: Parkinson's disease (PD) is described as an age-related neurodegenerative disorder. However, the vast majority of research is carried out using experimental models of young animals lacking the implications of the decline processes associated with aging. It has been suggested that several molecular pathways are involved in the perpetuation of the degeneration and the neuroinflammation in PD. Among others, mitogen-activated protein kinases (MAPKs) have been highly implicated in the development of PD, and regulating components of their activity are indicated as promising therapeutic targets. Methods: To further define how MAPKs expression is related to the glial response and neuronal cell death, Parkinsonism was induced under an acute regimen in old mice. Moreover, the sacrifice was carried out at different time points (4, 8, 24, and 48 h) after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) injections to describe the early dynamic changes over time produced by the intoxication. Results: The results revealed that neuronal death increases as glial response increases in the nigrostriatal pathway. It was observed that both processes increase from 4 h in the ventral mesencephalon (VM), and neuronal death becomes significant at 48 h. In the striatum, they were significantly increased from 48 h after the MPTP administration compared with that in the control mice. Moreover, the p-ERK levels decrease, while phospho-p38 expression increases specifically in the striatum at 48 h after MPTP intoxication. Conclusions: The importance of these data lies in the possibility of elucidating the underlying mechanisms of neurodegenerative processes under aging conditions to provide knowledge for the search of solutions that slow down the progression of PD.

16.
Pflugers Arch ; 472(7): 899-909, 2020 07.
Article in English | MEDLINE | ID: mdl-32577860

ABSTRACT

Investigating the Shaker-related K+ channel Kv1.1, the dysfunction of which is responsible for episodic ataxia 1 (EA1), at the functional and molecular level provides valuable understandings on normal channel dynamics, structural correlates underlying voltage-gating, and disease-causing mechanisms. Most studies focused on apparently functional amino acid residues composing voltage-gated K+ channels, neglecting the simplest ones. Glycine at position 311 of Kv1.1 is highly conserved both evolutionarily and within the Kv channel superfamily, is located in a region functionally relevant (the S4-S5 linker), and results in overt disease when mutated (p.G311D). By mutating the G311 residue to aspartate, we show here that the channel voltage-gating, activation, deactivation, inactivation, and window currents are markedly affected. In silico, modeling shows this glycine residue is strategically placed at one end of the linker helix which must be free to both bend and move past other portions of the protein during the channel's opening and closing. This is befitting of a glycine residue as its small neutral side chain allows for movement unhindered by interaction with any other amino acid. Results presented reveal the crucial importance of a distinct glycine residue, within the S4-S5 linker, in the voltage-dependent electromechanical coupling that control channel gating.


Subject(s)
Amino Acids/metabolism , Ion Channel Gating/physiology , Kv1.1 Potassium Channel/genetics , Amino Acid Sequence , Animals , Ataxia/metabolism , Ataxia/pathology , Xenopus laevis/metabolism
17.
PLoS One ; 15(5): e0233387, 2020.
Article in English | MEDLINE | ID: mdl-32437382

ABSTRACT

Real-time reverse transcription PCR (qPCR) normalized to an internal reference gene (RG), is a frequently used method for quantifying gene expression changes in neuroscience. Although RG expression is assumed to be constant independent of physiological or experimental conditions, several studies have shown that commonly used RGs are not expressed stably. The use of unstable RGs has a profound effect on the conclusions drawn from studies on gene expression, and almost universally results in spurious estimation of target gene expression. Approaches aimed at selecting and validating RGs often make use of different statistical methods, which may lead to conflicting results. Based on published RG validation studies involving hypoxia the present study evaluates the expression of 5 candidate RGs (Actb, Pgk1, Sdha, Gapdh, Rnu6b) as a function of hypoxia exposure and hypothermic treatment in the neonatal rat cerebral cortex-in order to identify RGs that are stably expressed under these experimental conditions-using several statistical approaches that have been proposed to validate RGs. In doing so, we first analyzed RG ranking stability proposed by several widely used statistical methods and related tools, i.e. the Coefficient of Variation (CV) analysis, GeNorm, NormFinder, BestKeeper, and the ΔCt method. Using the Geometric mean rank, Pgk1 was identified as the most stable gene. Subsequently, we compared RG expression patterns between the various experimental groups. We found that these statistical methods, next to producing different rankings per se, all ranked RGs displaying significant differences in expression levels between groups as the most stable RG. As a consequence, when assessing the impact of RG selection on target gene expression quantification, substantial differences in target gene expression profiles were observed. Altogether, by assessing mRNA expression profiles within the neonatal rat brain cortex in hypoxia and hypothermia as a showcase, this study underlines the importance of further validating RGs for each individual experimental paradigm, considering the limitations of the statistical methods used for this aim.


Subject(s)
Brain/metabolism , Gene Expression Profiling/methods , Genes, Essential , Hypothermia/genetics , Hypoxia, Brain/genetics , Animals , Animals, Newborn , Gene Expression , Hypothermia/metabolism , Hypoxia, Brain/metabolism , Rats , Real-Time Polymerase Chain Reaction/methods , Reproducibility of Results
18.
J Comp Neurol ; 528(11): 1833-1855, 2020 07 15.
Article in English | MEDLINE | ID: mdl-31950494

ABSTRACT

The hypothalamus contains catecholaminergic neurons marked by the expression of tyrosine hydroxylase (TH). As multiple chemical messengers coexist in each neuron, we determined if hypothalamic TH-immunoreactive (ir) neurons express vesicular glutamate or GABA transporters. We used Cre/loxP recombination to express enhanced GFP (EGFP) in neurons expressing the vesicular glutamate (vGLUT2) or GABA transporter (vGAT), then determined whether TH-ir neurons colocalized with native EGFPVglut2 - or EGFPVgat -fluorescence, respectively. EGFPVglut2 neurons were not TH-ir. However, discrete TH-ir signals colocalized with EGFPVgat neurons, which we validated by in situ hybridization for Vgat mRNA. To contextualize the observed pattern of colocalization between TH-ir and EGFPVgat , we first performed Nissl-based parcellation and plane-of-section analysis, and then mapped the distribution of TH-ir EGFPVgat neurons onto atlas templates from the Allen Reference Atlas (ARA) for the mouse brain. TH-ir EGFPVgat neurons were distributed throughout the rostrocaudal extent of the hypothalamus. Within the ARA ontology of gray matter regions, TH-ir neurons localized primarily to the periventricular hypothalamic zone, periventricular hypothalamic region, and lateral hypothalamic zone. There was a strong presence of EGFPVgat fluorescence in TH-ir neurons across all brain regions, but the most striking colocalization was found in a circumscribed portion of the zona incerta (ZI)-a region assigned to the hypothalamus in the ARA-where every TH-ir neuron expressed EGFPVgat . Neurochemical characterization of these ZI neurons revealed that they display immunoreactivity for dopamine but not dopamine ß-hydroxylase. Collectively, these findings indicate the existence of a novel mouse hypothalamic population that may signal through the release of GABA and/or dopamine.


Subject(s)
Hypothalamus/cytology , Neurons/cytology , Neurons/metabolism , Tyrosine 3-Monooxygenase/metabolism , Vesicular Inhibitory Amino Acid Transport Proteins/metabolism , Animals , Female , Hypothalamus/metabolism , Male , Mice , Vesicular Glutamate Transport Proteins/metabolism
19.
Mol Neurodegener ; 14(1): 48, 2019 12 20.
Article in English | MEDLINE | ID: mdl-31861987

ABSTRACT

The 3 day workshop "Alzheimer's Fast Track" is a unique opportunity for graduate students, postdoctoral fellows, or other early-career scientists, focused on Alzheimer's disease research, to gain new knowledge and become an expert in where this emerging scientific field is moving. In addition, it is not only about receiving a good overview, but also learning to write and defend a successful application for securing funding for Alzheimer's disease research projects.


Subject(s)
Alzheimer Disease , Dementia , Education , Research Personnel , Humans
20.
Front Neurosci ; 13: 1291, 2019.
Article in English | MEDLINE | ID: mdl-31866808

ABSTRACT

Cerebral small vessels feed and protect the brain parenchyma thanks to the unique features of the blood-brain barrier. Cerebrovascular dysfunction is therefore seen as a detrimental factor for the initiation of several central nervous system (CNS) disorders, such as stroke, cerebral small vessel disease (cSVD), and Alzheimer's disease. The main working hypothesis linking cerebrovascular dysfunction to brain disorders includes the contribution of neuroinflammation. While our knowledge on microglia cells - the brain-resident immune cells - has been increasing in the last decades, the specific populations of microglia and macrophages surrounding brain vessels, vessel-associated microglia (VAM), and perivascular macrophages (PVMs), respectively, have been overlooked. This review aims to summarize the knowledge gathered on VAM and PVMs, to discuss existing knowledge gaps of importance for later studies and to summarize evidences for their contribution to cerebrovascular dysfunction.

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