Reduced Tyrosine Hydroxylase Research Articles

Safety and antioxidant assessments of BLR-E50, 50% ethanolic extract from red beans co-fermented by Bacillus subtilis and Lactobacillus bulgaricus.

Since red beans have poor textural properties, fermentation is commonly used to help produce better pulse products. To obtain BLR-E50, red beans are fermented using a co-culture of Bacillus subtilis and Lactobacillus bulgaricus, followed by extraction with 50% ethanol. The present data demonstrate that BLR-E50 did not exhibit mutagenicity, genotoxicity, or subacute oral toxicity. BLR-E50 showed antioxidant abilities in vitro. Under H2O2-challenged conditions, the dietary addition of BLR-E50 extended the survival time of female Drosophila melanogaster (D. melanogaster). Meanwhile, BLR-E50 modulated the antioxidant system in H2O2-treated D. melanogaster. Oral administration of BLR-E50 also improved motor abilities and reduced tyrosine hydroxylase levels in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurodegeneration mouse model. Overall, this study presents that BLR-E50 is safe and possesses antioxidant, anti-aging, and neuroprotective capabilities, providing scientific evidence for the potential application of fermented red bean products as antioxidants in future dietary interventions.

PM2.5 Exposure Triggers Hypothalamic Oxidative and ER Stress Leading to Depressive-like Behaviors in Rats.

Epidemiological studies have linked fine dust pollution to depression, yet the underlying mechanisms remain unclear. Oxidative stress and endoplasmic reticulum (ER) stress are known contributors to depression, but their induction by particulate matter (PM), particularly PM2.5, in animal models has been limited. This study aimed to establish a rat model of PM2.5-induced depression-like behaviors and elucidate the underlying molecular mechanisms. Adult male Sprague-Dawley rats received daily intranasal PM2.5 for four weeks. Behavioral assessments, including the open field test (OFT), forced swim test (FST), and light-dark box (LDB) test, were conducted weekly. PM2.5-exposed rats displayed depressive-like behaviors, particularly in the FST, reflecting decreased motivation and learned helplessness. Molecular analyses indicated a specific increase in ER stress markers (CHOP, eIF2α, GRP78, and P16) and NOX4 in the hypothalamus, while other brain regions (striatum, cortex, and hippocampus) were not as pronounced. Additionally, PM2.5 exposure reduced tyrosine hydroxylase (TH) levels in the hypothalamus, suggesting impaired dopamine synthesis. These findings indicate that PM2.5 induces depressive-like behaviors via hypothalamic ER stress and oxidative stress pathways, leading to dopaminergic dysfunction. Targeting oxidative and ER stress within the hypothalamus may offer new therapeutic strategies for treating depression associated with environmental pollutants.

Phosphodiesterase inhibition and Gucy2C activation enhance tyrosine hydroxylase Ser40 phosphorylation and improve 6-hydroxydopamine-induced motor deficits

BackgroundParkinson’s disease is characterized by a progressive loss of dopaminergic neurons in the nigrostriatal pathway, leading to dopamine deficiency and motor impairments. Current treatments, such as L-DOPA, provide symptomatic relief but result in off-target effects and diminished efficacy over time. This study explores an alternative approach by investigating the activation of tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Specifically, we explore the effects of phosphodiesterase (PDE) inhibition and guanylate cyclase-C (GUCY2C) activation on tyrosine hydroxylase Ser40 phosphorylation and their impact on motor behavior in a 6-hydroxydopamine (6-OHDA) Parkinson's disease model.ResultsOur findings demonstrate that increasing cyclic nucleotide levels through PDE inhibition and GUCY2C activation significantly enhances tyrosine hydroxylase Ser40 phosphorylation. In a Pitx3-deficient mouse model, which mimics the loss of dopaminergic neurons seen in Parkinson’s disease, Ser40 phosphorylation remained manipulable despite reduced tyrosine hydroxylase protein levels. Moreover, we observed no evidence of tyrosine hydroxylase degradation due to Ser40 phosphorylation, challenging previous reports. Furthermore, both PDE inhibition and GUCY2C activation resulted in improved motor behavior in the 6-OHDA Parkinson’s disease mouse model, highlighting the potential therapeutic benefits of these approaches.ConclusionsThis study underscores the therapeutic potential of enhancing tyrosine hydroxylase Ser40 phosphorylation to improve motor function in Parkinson’s disease. Both PDE inhibition and GUCY2C activation represent promising non-invasive strategies to modulate endogenous dopamine biosynthesis and address motor deficits. These findings suggest that targeting cyclic nucleotide pathways could lead to novel therapeutic approaches, either as standalone treatments or in combination with existing therapies like L-DOPA, aiming to provide more durable symptom relief and potentially mitigate neurodegeneration in Parkinson's disease.

Superior cervical ganglionectomy attenuates vascular remodeling in spontaneously hypertensive rats.

Sympathetic hyperactivity contributes to the pathogenesis of hypertension. However, it is unclear whether the excessive sympathetic activity is an independent and crucial factor for vascular remodeling in hypertension. This study focused on the effect of local sympathetic denervation with superior cervical ganglionectomy (SCGx) on vascular remodeling. Surgical bilateral SCGx was performed in 9-week-old male Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Control rats received sham-operation without SCGx. All measurements were made 4 weeks after the surgery. The effectiveness of SCGx was confirmed by the eye features of Horner syndrome, greatly reduced tyrosine hydroxylase (TH) contents in the superior cervical ganglion (SCG)-innervated arteries in the head. Although SCGx had no significant effects on blood pressure and heart rate in WKY and SHR, it attenuated vascular remodeling of facial artery and superficial temporal artery in SHR, two representative SCG-innervated extracranial arteries, without significant effects on non-SCG-innervated thoracic aorta and mesenteric artery. SCGx-treated SHR had more auricular blood flow and retina microvasculature than sham-operated SHR. However, SCGx had only a mild effect in attenuating the vascular remodeling of basilar artery and middle cerebral artery, two representative SCG-innervated intracranial arteries, in SHR. SCGx-treated SHR exhibited upregulation of α-smooth muscle actin, downregulation of proliferating cell nuclear antigen, and attenuation of oxidative stress and inflammation in facial artery and superficial temporal artery. Sympathetic denervation by SCGx in SHR attenuated local vascular remodeling, suggesting that sympathetic overactivity is a crucial pathogenic factor of vascular remodeling in SHR.

Early expression of monomeric and oligomeric alpha-synuclein and reduction of tyrosine hydroxylase following intranigral injection of lipopolysaccharide

Early expression of monomeric and oligomeric alpha-synuclein and reduction of tyrosine hydroxylase following intranigral injection of lipopolysaccharide

Impaired olfactory performance and anxiety-like behavior in a rat model of multiple sclerosis are associated with enhanced adenosine signaling in the olfactory bulb via A1R, A2BR, and A3R.

The present study shows that animals with experimental autoimmune encephalomyelitis (EAE) exhibit olfactory dysfunction and impaired general cognitive abilities, as well as anxiety-like behavior. Olfactory dysfunction occurs on average at 2 dpi, well before the onset of the first motor signs of EAE (8-10 dpi). After the initial olfactory dysfunction, the EAE animals show a fluctuation in olfactory performance that resembles the relapsing-remitting course of human MS. The study also shows severe neuroinflammation in the olfactory bulb (OB), with numerous infiltrated CD4+ T cells and peripheral macrophages in the superficial OB layers, marked microgliosis, and massive induction of TNF-α, IL-1β, and IL-6. Reduced tyrosine hydroxylase activity in the glomerular layer, pronounced granule cell atrophy, and reduced numbers of type B neuroblasts in the rostral migratory stream also indicate altered plasticity of the neuronal network in the OB. Considering the exceptionally high purinome expression in the OB, the possible involvement of purinergic signaling was also investigated. The study shows that macrophages infiltrating the OB overexpress A3R, while highly reactive microglia overexpress the adenosine-producing enzyme eN/CD73 as well as A2BR, A3R, and P2X4R. Given the simultaneous induction of complement component C3, the results suggest that the microglial cells develop a functional phenotype of phagocytizing microglia. The study also demonstrates transcriptional and translational upregulation of A1R in mitral and tufted cells, which likely influence resting network activity in OB and likely contribute to olfactory dysfunction in EAE. Overall, our study shows that olfactory dysfunction and altered social and cognitive behavior in EAE are associated with increased adenosine signaling via A1R, A2BR, and A3R.

Effects of Chronic Exposure to Low Doses of Rotenone on Dopaminergic and Cholinergic Neurons in the CNS of Hemigrapsus sanguineus.

Rotenone, as a common pesticide and insecticide frequently found in environmental samples, may be present in aquatic habitats worldwide. Exposure to low concentrations of this compound may cause alterations in the nervous system, thus contributing to Parkinsonian motor symptoms in both vertebrates and invertebrates. However, the effects of chronic exposure to low doses of rotenone on the activity of neurotransmitters that govern motor functions and on the specific molecular mechanisms leading to movement morbidity remain largely unknown for many aquatic invertebrates. In this study, we analyzed the effects that rotenone poisoning exerts on the activity of dopamine (DA) and acetylcholine (ACh) synthesis enzymes in the central nervous system (CNS) of Asian shore crab, Hemigrapsus sanguineus (de Haan, 1835), and elucidated the association of its locomotor behavior with Parkinson's-like symptoms. An immunocytochemistry analysis showed a reduction in tyrosine hydroxylase (TH) in the median brain and the ventral nerve cord (VNC), which correlated with the subsequent decrease in the locomotor activity of shore crabs. We also observed a variation in cholinergic neurons' activity, mostly in the ventral regions of the VNC. Moreover, the rotenone-treated crabs showed signs of damage to ChAT-lir neurons in the VNC. These data suggest that chronic treatment with low doses of rotenone decreases the DA level in the VNC and the ACh level in the brain and leads to progressive and irreversible reductions in the crab's locomotor activity, life span, and changes in behavior.

Lead specifically declines tyrosine hydroxylase activity to induce the onset of Parkinson's disease through disrupting dopamine biosynthesis in fly models

Parkinson's disease (PD) is one of the fastest-growing neurodegenerative diseases and has been linked to the exposure to numerous environmental neurotoxins. Although lead (Pb) exposure has been related to the development of PD, the molecular target of Pb to cause the onset of PD is insufficiently investigated. Herein, we explored the effects of Pb exposure on behavior, pathophysiology, and gene expression of wild-type (WT) fly (Drosophila melanogaster) by comparison with its PD model. After exposure to Pb, the WT flies showed PD-like locomotor impairments and selective loss of dopaminergic (DAergic) neurons, displaying similar phenotypes to fly PD model (PINK1). Transcriptomic analysis showed the similarity in gene expression profiles between Pb treatment WT flies and PINK1 mutant flies. Moreover, Pb exposure resulted in endogenous dopamine deficits in WT flies. Analyses of gene expression and enzyme activity confirmed that Pb exposure reduced tyrosine hydroxylase (TH) activity and led to failure of dopamine synthesis. Furthermore, molecular dynamics simulation confirmed that Pb was adsorbed by TH and subsequently inhibited the enzymatic activity. Exogenous injection of L-dopa and melatonin could partially rescue the pathological phenotypes of Pb-exposed flies and PD fly model. Antagonist injection of microRNA-133, which negatively regulated the expression of TH gene, ultimately rescued in the manifestation of PD phenotypes in flies. Involvement of TH overexpression mutants of fly strongly promoted the resistance to Pb exposure and rescued both behavior and the number of DAergic neurons. Therefore, our study elucidates the Pb molecular target in dopamine pathway and mechanism underlying the risks of Pb exposure on the occurrence of PD at environmentally-relevant concentrations.

Impact of rotenone induced Parkinson’s disease on respiration and swallowing rate in drinking rats

Parkinson’s disease is a neurodegenerative disorder known to cause dysphagia, the major contributor to mortality via aspiration pneumonia. The neurological basis of swallowing dysfunction in Parkinson patients is poorly understood. To explore the mechanisms of swallowing dysfunction, we studied the impact of rotenone treatment on respiration rate and swallowing rate in liquid-drinking rats. We hypothesized that rotenone treatment will cause a decrease in respiratory and swallowing rate compared to untreated liquid-drinking rats. Six rats were injected with 2.75 mg/kg/day intraperitoneal rotenone for 16 days to create the parkinsonian phenotype and subsequently recorded with 200fps video fluoroscopy during barium-infused liquid drinking. Before the first injection and on day 4, 7, 10 and 16, the number of swallows and number of breaths in a ten second period of continuous drinking were scored. The data was then analyzed using Analysis of Variance to determine whether the rotenone injections impacted the respiration or swallowing rate. Rotenone injections led to a decrease in respiration rate (p=0.03), but no change in swallowing rate over a 16-day period (p>0.05). Immunohistochemistry of the dorsolateral striatum of rats that received rotenone treatment for 8 days and 16 days showed significant reduction in tyrosine hydroxylase (TH) immunofluorescence with increased impact due to prolonged treatment (Kruskal Wallis test, p<0.001). TH is the rate limiting step of catecholamine synthesis from tyrosine, confirming that rotenone is affecting dopamine production in this model of Parkinson’s disease. These results indicated that rotenone induced parkinsonian treatment has differential impacts on different brainstem mediated processes, swallowing and respiration. Thus, swallow-respiration coordination is likely impacted in these animals, potentially increasing risk of airway protection failure. Internal Rowan funding to F. Gould supported this work. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 1124: Sympathetic Denervation Models In Murine Femoral Arteries: Acute To Chronic Effects Of 6-hydroxydopamine

Introduction: The autonomic nervous system (ANS) drives blood flow regulation in peripheral arteries. This study aims to develop novel models of sympathetic denervation in peripheral arteries and to characterize subsequent vascular remodeling. We hypothesize that sympathetic denervation of murine femoral arteries can be achieved through local administration of neurotoxin 6-hydroxydopamine (6-OHDA). Methods: BALB/c mice underwent local administration of 6-OHDA to the left femoral artery, while the contralateral artery received vehicle solution. Two approaches were tested: (1) Acute: a one-time topical application following surgical exposure of femoral arteries (N=8, male, Fig. A ), and (2) Chronic: weekly subcutaneous injections near the femoral arteries (N=11, male and female, Fig. B ). Hindlimb perfusion was assessed with laser Doppler imaging, and arterial structure and remodeling were evaluated with histology and immunohistochemistry at one, two, or four weeks. Results: One-time 6-OHDA application (Acute) led to temporary femoral artery denervation (reduction in tyrosine hydroxylase) for one week ( Fig. C – D ), with inflammation observed in both 6-OHDA and vehicle-treated arteries. No vascular wall remodeling was observed after temporary denervation. Weekly subcutaneous 6-OHDA injections (Chronic) resulted in persistent denervation throughout the four-week period in male mice, while female mice displayed variable outcomes ( Fig. E – F ). Sustained sympathetic denervation in the chronic model led to reduced hindlimb blood perfusion at low core temperatures ( Fig. G – H ), though no significant differences were detected in vascular smooth muscle cell phenotype or extracellular matrix composition. Conclusions: Local administration of 6-OHDA is an effective means of peripheral artery sympathetic denervation with controllable duration. This innovative approach of targeting the ANS unveils new prospects for advancing vascular therapies.

Deficits in basal and evoked striatal dopamine release following alpha-synuclein preformed fibril injection: An in vivo microdialysis study.

Parkinson's disease (PD) is characterized by the accumulation of misfolded alpha-synuclein (α-syn) protein, forming intraneuronal Lewy body (LB) inclusions. The α-syn preformed fibril (PFF) model of PD recapitulates α-syn aggregation, progressive nigrostriatal degeneration and motor dysfunction; however, little is known about the time course of PFF-induced alterations in basal and evoked dopamine (DA). In vivo microdialysis is well suited for identifying small changes in neurotransmitter levels over extended periods. In the present study, adult male Fischer 344 rats received unilateral, intrastriatal injections of either α-syn PFFs or phosphate-buffered saline (PBS). At 4 or 8 months post-injection (p.i.), animals underwent in vivo microdialysis to evaluate basal extracellular striatal DA and metabolite levels, local KCl-evoked striatal DA release and the effects of systemic levodopa (l-DOPA). Post-mortem analysis demonstrated equivalent PFF-induced reductions in tyrosine hydroxylase (TH) immunoreactive nigral neurons (~50%) and striatal TH (~20%) at both time points. Compared with reduction in striatal TH, reduction in striatal dopamine transporter (DAT) was more pronounced and progressed between the 4- and 8-month p.i. intervals (36%➔46%). Significant PFF-induced deficits in basal and evoked striatal DA, as well as deficits in motor performance, were not observed until 8 months p.i. Responses to l-DOPA did not differ regardless of PBS or PFF treatment. These results suggest that basal and evoked striatal DA are maintained for several months following PFF injection, with loss of both associated with motor dysfunction. Our studies provide insight into the time course and magnitude of PFF-induced extracellular dopaminergic deficits in the striatum.

A Simple Immunofluorescence Method to Characterize Neurodegeneration and Tyrosine Hydroxylase Reduction in Whole Brain of a Drosophila Model of Parkinson's Disease.

Dopaminergic (DAergic) neurodegeneration in the substantia nigra pars compacta of the human brain is the pathological feature associated with Parkinson's disease (PD). Drosophila also exhibits mobility defects and diminished levels of brain dopamine on exposure to neurotoxicants mimicking PD. Our laboratory demonstrated in a Drosophila model of sporadic PD that there is no decrease in DAergic neuronal number; instead, there is a significant reduction in tyrosine hydroxylase (TH) fluorescence intensity (FI). Here, we present a sensitive assay based on the quantification of FI of the secondary antibody (ab). As the FI is directly proportional to the amount of TH synthesis, its reduction under PD conditions denotes the decrease in the TH synthesis, suggesting DAergic neuronal dysfunction. Therefore, FI quantification is a refined and sensitive method to understand the early stages of DAergic neurodegeneration. FI quantification is performed using the ZEN 2012 SP2 single-user software; a license must be acquired to utilize the imaging system to interactively control image acquisition, image processing, and analysis. This method will be of good use to biologists, as it can also be used with little modification to characterize the extent of degeneration and changes in the level of degeneration in response to drugs in different cell types. Unlike the expensive and cumbersome confocal microscopy, the present method will be an affordable option for fund-constrained neurobiology laboratories. Key features • Allows characterizing the incipient DAergic and other catecholaminergic neurodegeneration, even in the absence of loss of neuronal cell body. • Great alternative for the fund-constrained neurobiology laboratories in developing countries to utilize this method in different cell types and their response to drugs/nutraceuticals.

Empagliflozin repurposing in Parkinson’s disease; modulation of oxidative stress, neuroinflammation, AMPK/SIRT-1/PGC-1α, and wnt/β-catenin pathways

Parkinson's disease is a neuroprogressive disorder characterized by loss of dopaminergic neurons in substantia nigra pars compacta. Empagliflozin (EMPA), a SGLT-2 inhibitor, is an oral hypoglycemic agent with reported anti-inflammatory and antioxidant effects. The current study aimed to evaluate the neuroprotective effect of EMPA in rotenone-induced Parkinson's disease. Rats were randomly distributed among five groups as follows: control, rotenone (2 mg/kg), rotenone + EMPA (10 mg/kg), rotenone + EMPA (20 mg/kg), and EMPA (20 mg/kg) groups. They were treated for 30 consecutive days. Rotenone reduced locomotor activity and retention time on the rotarod performance test while elongated descent latency time. On the other side, EMPA corrected these behavioral changes. These results were confirmed by histological examination and number of intact neurons. Moreover, rotenone induced alpha-synuclein accumulation, reduced tyrosine hydroxylase expression, dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid concentrations. On the other side, EMPA reversed such effects induced by rotenone. Depending on previous results, EMPA (20 mg/kg) was selected for further mechanistic studies. Rotenone ameliorated superoxide dismutase and catalase activities and enhanced lipid peroxidation, interleukin-1β, and tumor necrosis factor-α levels. By contrast, EMPA opposed rotenone-induced effects on oxidative stress and inflammation. Besides, rotenone reduced the expression of pAMP-activated protein kinase (pAMPK), peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), and Sirtuin-1 (SIRT-1), as well as abrogated NAD+/NADH ratio. However, EMPA activated the AMPK/SIRT-1/PGC-1α pathway. Moreover, rotenone hindered the wnt/β-catenin pathway by reducing the wnt-3a level and β-catenin expression. On the other side, EMPA triggered activation of the wnt/β-catenin pathway. Collectively, EMPA may provide a promising solution for Parkinson's patients worldwide.

Novel HDAC inhibitors provide neuroprotection in MPTP-induced Parkinson's disease model of rats

Parkinson's Disease (PD) is the most rapidly growing neurological disorder globally in terms of disability and mortality. While symptomatic treatment is available for PD, there is a critical unmet need for effective disease-modifying therapies. Recently, histone deacetylase inhibitors (HDACi), an important class of epigenetic modulators grabbed significant attention as drug targets for neurodegenerative diseases including PD. In this regard, novel pan-HDACi, cinnamyl sulphonamide hydroxamate derivatives (NMJ-2 and NMJ-3), synthesized and characterized in our laboratory, were screened for neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) rat model of PD. Twenty-four hours after the bilateral intranigral injection of MPTP, rats were administered orally with NMJ-2 or NMJ-3 (150 mg/kg) daily for 30 days. MPTP administration resulted in a marked rise in lipid peroxidation, and interleukin-1β concentration accompanied by reduced tyrosine hydroxylase and dopamine levels in the striatum compared to the sham group. These biochemical changes were associated with functional motor and non-motor deficits as revealed by loss of motor coordination (rota rod test), impaired grip strength (beam walk test), enhanced rigidity (catalepsy scores), loss of memory (novel object recognition test) and depressive-like behaviour (forced swim test). However, oral treatment with NMJ-2 or NMJ-3, or valproic acid for 30 days significantly attenuated the PD-induced adverse changes in motor and non-motor functions by ameliorating the oxidative stress as well as inflammation, and restoring the dopamine levels in the striatum comparable to the valproic acid group. These results suggest that targeting HDACi could be a rational therapeutic strategy for the development of disease-modifying therapies for PD.

Microglial depletion exacerbates motor impairment and dopaminergic neuron loss in a 6-OHDA model of Parkinson's disease

6-hydroxydopamine (6-OHDA) is a common neurotoxin used to induce Parkinson's disease (PD) in mice, exerting neurotoxic effects through the production of reactive oxygen species and microglial activation. However, the role of microglia in PD is still not clear, with contradictory reports showing neuroprotection or exacerbation of neuronal death. Microglial depletion aggravates motor coordination impairments and reduces tyrosine hydroxylase positive neurons in the substantia nigra pars compacta. Moreover, MeCP2 and Adora1 genes expression were downregulated, suggesting they may be involved in the neurodegenerative process. This study highlights that microglia plays a protective role in dopaminergic neuron survival during the initial phase of PD, and the investigation of the mechanisms of this effect in future studies will help elucidate the pathophysiology of PD.

Exosomes from Inflamed Macrophages Promote the Progression of Parkinson's Disease by Inducing Neuroinflammation.

Inflammation is a common feature both for Parkinson's disease (PD) and obesity-associated metabolic syndromes. Inflammation mediated by inflamed macrophages in white adipose tissue plays a pivotal role for the pathogenesis of metabolic syndromes. Exosomes are important carriers connecting peripheral tissues and the central nervous system (CNS). Therefore, we speculate that exosomes derived from inflamed macrophages may be involved in the pathological progression of PD. Here, we prepared exosomes from lipopolysaccharide (LPS) or interferon gamma (IFNγ) treated macrophages (inflamed macrophages) and examined their potential roles in PD. Our data showed that exosomes from inflamed macrophages stimulate proinflammatory cytokine expression in primary microglia and astrocytes. In vivo, inflamed macrophage exosomes induce behavioral defects in mice as evidenced by shortened duration in the rotarod test and prolonged latency in the pole test. The treatment of exosomes also reduces tyrosine hydroxylase (TH) positive cells in the substantia nigra pars compacta (SNpc) and striatum. All these PD-like phenotypes are likely due to the activation of microglia and astrocytes induced by exosomes from inflamed macrophages. Exosome sequencing, together with bioinformatics analysis and functional studies, revealed that exosomal miRNAs such as miR-155-5p are likely a key factor for inducing an inflammatory response in glial cells. These results indicate that exosomes derived from inflamed macrophages are likely a causative factor for developing PD. In this regard, inflamed macrophage exosomes might be a linker transducing the peripheral tissue inflammation into the CNS.

Benefits of p-coumaric acid in mice with rotenone-induced neurodegeneration.

The paper examines the use of natural antioxidant and anti-inflammation substances as therapeutic candidates for brain disease. Para-coumaric acid (pCA), a phenolic compound with a variety of medicinal properties, was used against deterioration caused by various diseases. Recently, pCA has gained attention for use against cardiovascular disease but less so for neurodegenerative disease (i.e., Parkinson's disease). Therefore, the present study intended to investigate the effect of pCA against rotenone-induced Parkinson's disease-like pathology in mice. Thirty male institute of cancer research (ICR) mice were randomly divided into three experimental groups: Sham-veh, Rot-veh, and Rot-pCA100. Rotenone (Rot) 2.5mg/kg was subcutaneously injected every 48h in the rotenone groups. Alternately, a 100mg/kg pCA dose was given every 48h via intragastric gavage to the Rot-pCA100 group for 6weeks. Motor ability was assessed at the second, fourth, and sixth week before brain collection for biochemical and histological analyses. Results indicated significant motor deficits appeared from the second to sixth week after rotenone injection. Brain analysis detected a significant effect of rotenone in the increase of malondialdehyde and tumor necrosis factor-alpha (TNF-α). This result was observed in accordance with a reduction of tyrosine hydroxylase (TH) and an increase of neuronal degeneration in the substantia nigra par compacta (SNc) and striatum. However, pCA was able to reverse all of the deterioration (i.e., reduced malondialdehyde and TNF-α) rotenone had caused, and it protected against TH and neuronal loss in the SNc and striatum. Therefore, the present study has depicted the neuroprotective effect of pCA against rotenone-induced Parkinson's disease-like pathology in mice. Benefits of pCA include anti-lipid peroxidation and anti-inflammatory effects, inhibition of neurodegeneration, and a nurturing effect on the TH level in the SNc and striatum, leading to mitigation of motor deficits.

Leptin and adiponectin regulate the activity of nuclei involved in sleep-wake cycle in male rats.

Epidemiological and experimental evidence recognize a relationship between sleep-wake cycles and adiposity levels, but the mechanisms that link both are not entirely understood. Adipose tissue secretes adiponectin and leptin hormones, mainly involved as indicators of adiposity levels and recently associated to sleep. To understand how two of the main adipose tissue hormones could influence sleep-wake regulation, we evaluated in male rats, the effect of direct administration of adiponectin or leptin in the ventrolateral preoptic nuclei (VLPO), a major area for sleep promotion. The presence of adiponectin (AdipoR1 and AdipoR2) and leptin receptors in VLPO were confirmed by immunohistochemistry. Adiponectin administration increased wakefulness during the rest phase, reduced delta power, and activated wake-promoting neurons, such as the locus coeruleus (LC), tuberomammillary nucleus (TMN) and hypocretin/orexin neurons (OX) within the lateral hypothalamus (LH) and perifornical area (PeF). Conversely, leptin promoted REM and NREM sleep, including increase of delta power during NREM sleep, and induced c-Fos expression in VLPO and melanin concentrating hormone expressing neurons (MCH). In addition, a reduction in wake-promoting neurons activity was found in the TMN, lateral hypothalamus (LH) and perifornical area (PeF), including in the OX neurons. Moreover, leptin administration reduced tyrosine hydroxylase (TH) immunoreactivity in the LC. Our data suggest that adiponectin and leptin act as hormonal mediators between the status of body energy and the regulation of the sleep-wake cycle.

Dual-Hit Model of Parkinson's Disease: Impact of Dysbiosis on 6-Hydroxydopamine-Insulted Mice-Neuroprotective and Anti-Inflammatory Effects of Butyrate.

Recent evidence highlights Parkinson’s disease (PD) initiation in the gut as the prodromal phase of neurodegeneration. Gut impairment due to microbial dysbiosis could affect PD pathogenesis and progression. Here, we propose a two-hit model of PD through ceftriaxone (CFX)-induced dysbiosis and gut inflammation before the 6-hydroxydopamine (6-OHDA) intrastriatal injection to mimic dysfunctional gut-associated mechanisms preceding PD onset. Therefore, we showed that dysbiosis and gut damage amplified PD progression, worsening motor deficits induced by 6-OHDA up to 14 days post intrastriatal injection. This effect was accompanied by a significant increase in neuronal dopaminergic loss (reduced tyrosine hydroxylase expression and increased Bcl-2/Bax ratio). Notably, CFX pretreatment also enhanced systemic and colon inflammation of dual-hit subjected mice. The exacerbated inflammatory response ran in tandem with a worsening of colonic architecture and gut microbiota perturbation. Finally, we demonstrated the beneficial effect of post-biotic sodium butyrate in limiting at once motor deficits, neuroinflammation, and colon damage and re-shaping microbiota composition in this novel dual-hit model of PD. Taken together, the bidirectional communication of the microbiota–gut–brain axis and the recapitulation of PD prodromal/pathogenic features make this new paradigm a useful tool for testing or repurposing new multi-target compounds in the treatment of PD.

EEF1A2 knockdown impairs neuronal proliferation and inhibits neurite outgrowth of differentiating neurons.

The translation elongation factor-1, alpha-2 (eEF1A2) plays an important role in protein synthesis. Mutations in this gene have been described in individuals with neurodevelopmental disorders. Here, we silenced the expression of eEFA2 in human SH-SY5Y neuroblastoma cells and observed its roles in neuronal proliferation and differentiation upon induction with retinoic acid. eEF1A2 were silenced using siRNA transfection. Cell proliferation was qualitatively evaluated by Ki-67 immunocytochemistry. Neuronal differentiation was induced with retinoic acid for 3, 5, 7 and 10 days. Neurite length was measured. The expression of microtubule-associated protein 2 (MAP2) was analyzed by western blotting. Tyrosine hydroxylase expression was visualized by immunofluorescence. Cytotoxicity to a neurotoxin, 1-methyl-4-phenylpyridinium (MPP+), was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and western blotting of cleaved caspase-3. eEF1A2 knockdown suppressed the proliferative activity of undifferentiated SH-SY5Y cells as shown by decreased Ki-67 immunostaining. Upon retinoic acid-induction, differentiated neurons with eEF1A2 knockdown exhibited shorter neurite length than untransfected cells, which was associated with the reduction of tyrosine hydroxylase and suppression of MAP2 at 10 days of differentiation. eEF1A2 knockdown decreased the survival of neurons, which was clearly observed in undifferentiated and short-term differentiated cells. Upon treatment with MPP+, cells with eEF1A2 knockdown showed a further reduction in cell survival and an increase of cleaved caspase-3 protein. Our results suggest that eEF1A2 may be required for neuronal proliferation and differentiation of SH-SY5Y cells. Increased cell death susceptibility against MPP+ in eEF1A2-knockdown neurons may imply the neuroprotective role of eEF1A2.