PD Mouse Research Articles

Circular RNA circTLK1 regulates dopaminergic neuron injury during Parkinson‘s disease by targeting miR-26a-5p/DAPK1

BackgroundParkinson’s disease (PD) is a neurodegenerative disorder that is featured by the elevated loss of substantia nigra pars compacta dopaminergic neurons and the disruption of motor functions. Aberrant expression of circular RNAs (circRNAs) is correlated with neurodegenerative diseases. This study aimed to explore the role of circTLK1 in PD pathology. MethodsMPTP-stimulated in vivo PD mouse model and MPP + and rotenone-induced in vitro PD model were established to investigate the function of circTLK1/miR-26a-5p/DAPK1 axis during dopaminergic neuron injury. The motor function of mice was evaluated by using the Rotarod test. Brain tissue damage was checked by hematoxylin and eosin, TdT-mediated dUTP-biotin nick end labeling. Cell viability, apoptosis, and cytotoxicity were evaluated by cell counting kit 8 (CCK-8), flow cytometry, and LDH activity. The interaction between circTLK1 and miR-26a-5p as well as miR-26a-5p and DAPK1 was detected by luciferase reporter assay. ResultsThe expression of circTLK1 was notably elevated in in vitro and in vivo PD models. Knockdown of circTLK1 significantly improved cell viability, suppressed apoptosis and cytotoxicity, whereas inhibition of miR-16a-5p and overexpression of DAPK1 abolished these effects. MiR-26a-5p acts as a sponge of DAPK1 to mediate circTLK1 functions. Luciferase reporter gene assay confirmed the interaction between circTLK1 and miR-26a-5p as well as miR-26a-5p and DAPK1. ConclusionDepletion of circTLK1 mitigates dopaminergic neuron injury in vitro and in vivo, via releasing miR-26a-5p to target DAPK1 expression. Targeting circTLK1 may contribute to improving PD therapy.

MicroRNA-181a\u20132\u20133p shuttled by mesenchymal stem cell-secreted extracellular vesicles inhibits oxidative stress in Parkinson\u2019s disease by inhibiting EGR1 and NOX4

The current study investigated the physiological mechanisms by which extracellular vesicle (EV)-encapsulated miR-181a–2–3p derived from mesenchymal stem cells (MSCs) might mediate oxidative stress (OS) in Parkinson’s disease (PD). First, 6-hydroxydopamine (6-OHDA)-induced PD cell and mouse models were established, after which miR-181a–2–3p, EGR1, and NOX4 expression patterns were determined in SH-SY5Y cells and substantia nigra (SN) of PD mice. Next, the binding affinity among miR-181a–2–3p, EGR1, and NOX4 was identified using multiple assays. Gain- or loss-of-function experiments were further adopted to detect SH-SY5Y cell proliferation and apoptosis and to measure the levels of SOD, MDA, and ROS. Finally, the effects of miR-181a–2–3p from MSC-derived EVs in PD mouse models were also explored. It was found that miR-181a–2–3p was poorly expressed in 6-OHDA-induced SH-SY5Y cells, whereas miR-181a–2–3p from MSCs could be transferred into SH-SY5Y cells via EVs. In addition, miR-181a–2–3p could target and inhibit EGR1, which promoted the expression of NOX4. The aforementioned miR-181a–2–3p shuttled by MSC-derived EVs facilitated SH-SY5Y proliferation and SOD levels, but suppressed apoptosis and MDA and ROS levels by regulating EGR1 via inhibition of NOX4/p38 MAPK, so as to repress OS of PD. Furthermore, in PD mice, miR-181a–2–3p was carried by EVs from MSCs to alleviate apoptosis of dopamine neurons and OS, accompanied by increased expressions of α-syn and decreased 4-HNE in SN tissues. Collectively, our findings revealed that MSC-derived EV-loaded miR-181a–2–3p downregulated EGR1 to inhibit OS via the NOX4/p38 MAPK axis in PD.

Fecal microbiota transplantation protects rotenone-induced Parkinson\u2019s disease mice via suppressing inflammation mediated by the lipopolysaccharide-TLR4 signaling pathway through the microbiota-gut-brain axis

BackgroundParkinson’s disease (PD) is a prevalent neurodegenerative disorder, displaying not only well-known motor deficits but also gastrointestinal dysfunctions. Consistently, it has been increasingly evident that gut microbiota affects the communication between the gut and the brain in PD pathogenesis, known as the microbiota-gut-brain axis. As an approach to re-establishing a normal microbiota community, fecal microbiota transplantation (FMT) has exerted beneficial effects on PD in recent studies. Here, in this study, we established a chronic rotenone-induced PD mouse model to evaluate the protective effects of FMT treatment on PD and to explore the underlying mechanisms, which also proves the involvement of gut microbiota dysbiosis in PD pathogenesis via the microbiota-gut-brain axis.ResultsWe demonstrated that gut microbiota dysbiosis induced by rotenone administration caused gastrointestinal function impairment and poor behavioral performances in the PD mice. Moreover, 16S RNA sequencing identified the increase of bacterial genera Akkermansia and Desulfovibrio in fecal samples of rotenone-induced mice. By contrast, FMT treatment remarkably restored the gut microbial community, thus ameliorating the gastrointestinal dysfunctions and the motor deficits of the PD mice. Further experiments revealed that FMT administration alleviated intestinal inflammation and barrier destruction, thus reducing the levels of systemic inflammation. Subsequently, FMT treatment attenuated blood-brain barrier (BBB) impairment and suppressed neuroinflammation in the substantia nigra (SN), which further decreased the damage of dopaminergic neurons. Additional mechanistic investigation discovered that FMT treatment reduced lipopolysaccharide (LPS) levels in the colon, the serum, and the SN, thereafter suppressing the TLR4/MyD88/NF-κB signaling pathway and its downstream pro-inflammatory products both in the SN and the colon.ConclusionsOur current study demonstrates that FMT treatment can correct the gut microbiota dysbiosis and ameliorate the rotenone-induced PD mouse model, in which suppression of the inflammation mediated by the LPS-TLR4 signaling pathway both in the gut and the brain possibly plays a significant role. Further, we prove that rotenone-induced microbiota dysbiosis is involved in the genesis of PD via the microbiota-gut-brain axis.6NusmmVQuAXh_sD82L334KVideo abstract

Association of decreased triadin expression level with apoptosis of dopaminergic cells in Parkinson\u2019s disease mouse model

BackgroundParkinson’s disease (PD) represent a loss of dopaminergic neurons in the substantia nigra (SN) of the midbrain. However, its cause remains unknown and Triadin (TRDN) function in the brain is also unknown. To examine the relationship between TRDN and PD, the expression levels of protein related to PD in TRDN knockdown status were studied in the SH-SY5Y cells. Cell viability and apoptosis were assessed to examine the apoptosis effect on dopaminergic cells by decreased TRDN, and the levels of the proteins related to apoptosis were also confirmed.ResultsThis study confirmed decreased TRDN expression level (P < 0.005) at the SN in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced PD mouse model and identified the functional features of TRDN. Our results showed a relationship between TRDN expression and PD in that reduced TRDN level induced PD-like characteristics. Interestingly, there was TRDN expression in the regions where dopaminergic cells are in the SN, and the expression patterns of TRDN and tyrosine hydroxylase (TH) were similar. Decreased TRDN level also induced apoptotic characteristics and the Fluorescence-activated cell sorting analysis results showed that apoptosis increased (P < 0.05) as the TRDN small interfering RNA concentration increased. The cytotoxicity assay revealed that cell viability also decreased (P < 0.0005) in the same condition as that in the Fluorescence‐activated cell sorting analysis.ConclusionsDecreased TRDN level could be related with the apoptotic death of dopaminergic cells at the SN in PD, and TRDN administration could give a positive effect on PD by reducing apoptotic cell death.

The GLP-1 receptor agonist, liraglutide, fails to slow disease progression in SOD1G93A and TDP-43Q331K transgenic mouse models of ALS

GLP-1 receptor agonists used for the treatment of diabetes, have shown some neuroprotective effects in cellular and animal models of Alzheimer’s disease (AD) and Parkinson’s disease (PD). There are currently few studies investigating GLP-1 receptor agonists in the treatment of ALS, where these neuroprotective effects may be beneficial. Here we investigate the effects of liraglutide, a GLP-1 receptor agonist, in two well characterised transgenic mouse models of ALS (SOD1G93A and TDP-43Q331K) to determine if liraglutide could be a potential treatment in ALS patients. Doses of liraglutide previously shown to have efficacy in AD and PD mouse models were used. Behavioural testing was carried out to ascertain the effect of liraglutide on disease progression. Immunohistochemical analysis of tissue was used to determine any neuroprotective effects on the CNS. We found that liraglutide dosed animals showed no significant differences in disease progression when compared to vehicle dosed animals in either the SOD1G93A or TDP-43Q331K mouse models of ALS. We also observed no changes in motor neuron counts or glial activation in lumbar spinal cords of liraglutide treated mice compared to vehicle dosed mice. Overall, we found no evidence to support clinical evaluation of liraglutide as a potential candidate for the treatment of ALS.

Characterization of substantia nigra neurogenesis in homeostasis and dopaminergic degeneration: beneficial effects of the microneurotrophin BNN-20

BackgroundLoss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) underlines much of the pathology of Parkinson’s disease (PD), but the existence of an endogenous neurogenic system that could be targeted as a therapeutic strategy has been controversial. BNN-20 is a synthetic, BDNF-mimicking, microneurotrophin that we previously showed to exhibit a pleiotropic neuroprotective effect on the dopaminergic neurons of the SNpc in the “weaver” mouse model of PD. Here, we assessed its potential effects on neurogenesis.MethodsWe quantified total numbers of dopaminergic neurons in the SNpc of wild-type and “weaver” mice, with or without administration of BNN-20, and we employed BrdU labelling and intracerebroventricular injections of DiI to evaluate the existence of dopaminergic neurogenesis in the SNpc and to assess the origin of newborn dopaminergic neurons. The in vivo experiments were complemented by in vitro proliferation/differentiation assays of adult neural stem cells (NSCs) isolated from the substantia nigra and the subependymal zone (SEZ) stem cell niche to further characterize the effects of BNN-20.ResultsOur analysis revealed the existence of a low-rate turnover of dopaminergic neurons in the normal SNpc and showed, using three independent lines of experiments (stereologic cell counts, BrdU and DiI tracing), that the administration of BNN-20 leads to increased neurogenesis in the SNpc and to partial reversal of dopaminergic cell loss. The newly born dopaminergic neurons, that are partially originated from the SEZ, follow the typical nigral maturation pathway, expressing the transcription factor FoxA2. Importantly, the pro-cytogenic effects of BNN-20 were very strong in the SNpc, but were absent in other brain areas such as the cortex or the stem cell niche of the hippocampus. Moreover, although the in vitro assays showed that BNN-20 enhances the differentiation of NSCs towards glia and neurons, its in vivo administration stimulated only neurogenesis.ConclusionsOur results demonstrate the existence of a neurogenic system in the SNpc that can be manipulated in order to regenerate the depleted dopaminergic cell population in the “weaver” PD mouse model. Microneurotrophin BNN-20 emerges as an excellent candidate for future PD cell replacement therapies, due to its area-specific, pro-neurogenic effects.

Parkinson mice show functional and molecular changes in the gut long before motoric disease onset

BackgroundThere is increasing evidence that Parkinson’s disease (PD) might start in the gut, thus involving and compromising also the enteric nervous system (ENS). At the clinical onset of the disease the majority of dopaminergic neurons in the midbrain is already destroyed, so that the lack of early biomarkers for the disease represents a major challenge for developing timely treatment interventions. Here, we use a transgenic A30P-α-synuclein-overexpressing PD mouse model to identify appropriate candidate markers in the gut before hallmark symptoms begin to manifest.MethodsBased on a gait analysis and striatal dopamine levels, we defined 2-month-old A30P mice as pre-symptomatic (psA30P), since they are not showing any motoric impairments of the skeletal neuromuscular system and no reduced dopamine levels, but an intestinal α-synuclein pathology. Mice at this particular age were further used to analyze functional and molecular alterations in both, the gastrointestinal tract and the ENS, to identify early pathological changes. We examined the gastrointestinal motility, the molecular composition of the ENS, as well as the expression of regulating miRNAs. Moreover, we applied A30P-α-synuclein challenges in vitro to simulate PD in the ENS.ResultsA retarded gut motility and early molecular dysregulations were found in the myenteric plexus of psA30P mice. We found that i.e. neurofilament light chain, vesicle-associated membrane protein 2 and calbindin 2, together with the miRNAs that regulate them, are significantly altered in the psA30P, thus representing potential biomarkers for early PD. Many of the dysregulated miRNAs found in the psA30P mice are reported to be changed in PD patients as well, either in blood, cerebrospinal fluid or brain tissue. Interestingly, the in vitro approaches delivered similar changes in the ENS cultures as seen in the transgenic animals, thus confirming the data from the mouse model.ConclusionsThese findings provide an interesting and novel approach for the identification of appropriate biomarkers in men.

Nervonic acid amends motor disorder in a mouse model of Parkinson's disease.

ObjectivesParkinson’s disease (PD) is a kind of common neurodegenerative disease in the world. Previous studies have proved that nervonic acid (NA), extracted from Xanthoceras sorbifolia Bunge, has the potentials of neuroprotection. However, the effect of NA on the PD remained unknown. This study was designed to investigate the NA’s potential function and relative mechanism on motor disorder.Methods1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was used for producing parkinsonism motor disorder on male C57BL/6 mice. Toxicity experiments and behavioral assay were performed to evaluate the effect of NA. Besides, the expression levels of tyrosine hydroxylase and α-synuclein, as well as striatal dopamine (DA), serotonin, and their metabolites were explored through immunoblotting and chromatography after NA treatment in vivo.ResultsWe found that NA could alleviate the MPTP-induced behavioral deficits dose-dependently. Moreover, NA has no toxic effects on the mouse liver and kidney. Of note, we found that NA significantly reduced the impact of MPTP impairment and striatal DA, serotonin, and metabolites were remained unaffected. In addition, tyrosine hydroxylase was upregulated while α-synuclein being downregulated and the oxidative stress was partially repressed evidenced by the upregulation of superoxide dismutase and glutathione activity after NA treatment.ConclusionOur findings unveil NA’s potential for protecting motor system against motor disorder in the PD mouse model without any side effects, indicating NA as an alternative strategy for PD symptom remission.

Quercetin hinders microglial activation to alleviate neurotoxicity via the interplay between NLRP3 inflammasome and mitophagy

Activated microglia are an important type of innate immune cell in the brain, and they secrete inflammatory cytokines into the extracellular milieu, exert neurotoxicity to surrounding neurons and are involved in the pathogenesis of many brain disorders. Quercetin (Qu), a natural flavonoid, is known to have anti-inflammatory and antioxidant properties. Previous studies have shown that both increased reactive oxygen species (ROS) stress and decreased autophagy participate in the activation of microglial. In the current study, we showed that Qu significantly attenuated LPS-induced inflammatory factor production, cell proliferation and NF-κB activation of microglia. Importantly, Qu decreased the levels of NLR family, pyrin domain containing three (NLRP3) inflammasome and pyroptosis-related proteins, including NLRP3, active caspase-1, GSDMD N-terminus and cleaved IL-1β. Further study indicated that this anti-inflammatory effect of Qu was associated with mitophagy regulation. Importantly, Qu promoted mitophagy to enhance damaged mitochondrial elimination, which then reduced mtROS accumulation and alleviated NLRP3 inflammasome activation. Then, we confirmed that Qu treatment protected primary neurons against LPS-induced microglial toxicity and alleviated neurodegeneration in both depression and PD mouse models. Further IL-1β administration blunted these neuroprotective effects of Qu in vitro and in vivo. This work illustrated that Qu prevents neuronal injury via inhibition of mtROS-mediated NLRP3 inflammasome activation in microglia through promoting mitophagy, which provides a potential novel therapeutic strategy for neuroinflammation-related diseases.

The DJ1-Nrf2-STING axis mediates the neuroprotective effects of Withaferin A in Parkinson\u2019s disease

The pathogenesis of Parkinson’s disease (PD) remains unclear, and there is no disease-modifying agent for PD. Withaferin A (WA), a naturally occurring compound, has emerged as a neuroprotective agent. However, the mechanisms by which WA is neuroprotective in PD are unknown. Here we show that WA protected against loss of dopaminergic neurons, neuroinflammation, and motor deficits in MPTP-induced PD mouse models. Whole-genome deep sequencing analysis combined with Meta-analysis of human PD studies reveal that DJ1, Nrf2, and STING in substantia nigra pars compacta (SNc) are linked to anti-PD effect of WA. We found that WA activated DJ1 and Nrf2, and suppressed STING within SNc; and overexpression of STING in SNc dampened the effect of WA. Using genetically modified mice (DJ1-KO, Nrf2-KO, STINGgt/gt and STING-KO) and immunolabeling technique, we identified that WA targeted DJ1-Nrf2-STING pathway in dopaminergic neurons; and we demonstrate that STING might be an important factor in PD pathogenesis. In addition, WA alleviated accumulation of phosphorylated α-synuclein (p-α-syn) and insoluble α-syn within SNc in adeno-associated virus (AAV)-mediated human α-syn overexpression PD model. Our comparative analysis on whole-genome transcriptome profiles suggests that STING might be a key target of WA and amantadine in PD treatment. This study highlights a multifaceted role for WA in neuroprotection, and suggests that WA can be a potential candidate for treatment of PD.

Opposing functions of \u03b2-arrestin 1 and 2 in Parkinson\u2019s disease via microglia inflammation and Nprl3

Although β-arrestins (ARRBs) regulate diverse physiological and pathophysiological processes, their functions and regulation in Parkinson’s disease (PD) remain poorly defined. In this study, we show that the expression of β-arrestin 1 (ARRB1) and β-arrestin 2 (ARRB2) is reciprocally regulated in PD mouse models, particularly in microglia. ARRB1 ablation ameliorates, whereas ARRB2 knockout aggravates, the pathological features of PD, including dopaminergic neuron loss, neuroinflammation and microglia activation in vivo, and microglia-mediated neuron damage in vitro. We also demonstrate that ARRB1 and ARRB2 produce adverse effects on inflammation and activation of the inflammatory STAT1 and NF-κB pathways in primary cultures of microglia and macrophages and that two ARRBs competitively interact with the activated form of p65, a component of the NF-κB pathway. We further find that ARRB1 and ARRB2 differentially regulate the expression of nitrogen permease regulator-like 3 (Nprl3), a functionally poorly characterized protein, as revealed by RNA sequencing, and that in the gain- and loss-of-function studies, Nprl3 mediates the functions of both ARRBs in microglia inflammatory responses. Collectively, these data demonstrate that two closely related ARRBs exert opposite functions in microglia-mediated inflammation and the pathogenesis of PD which are mediated at least in part through Nprl3 and provide novel insights into the understanding of the functional divergence of ARRBs in PD.

Dose-related biphasic effect of the Parkinson’s disease neurotoxin MPTP, on the spread, accumulation, and toxicity of α-synuclein

BackgroundParkinson’s disease (PD), the second most common progressive neurodegenerative disorder, is characterized by the abnormal accumulation of intraneuronal inclusions enriched in aggregated α-synuclein (α-syn), known as Lewy bodies (LBs) and Lewy neurites (LNs), and significant loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) of the brain. Recent evidence suggests that the intrastriatal inoculation of α-syn preformed fibrils (PFF) in mice brain triggers endogenous α-syn in interconnected brain regions. 1-methyl, 4-phenyl, 1,2,3,6 tetrahydropyridine (MPTP), a mitochondrial neurotoxin, has been used previously to generate a PD mouse model. However, the common methods of MPTP exposure do not induce LB or α-syn aggregation in mice. In the present study, we evaluated the effect of different doses of MPTP (10 mg/kg.b.wt and/or 25 mg/kg.b.wt) on the spread, accumulation, and toxicity of endogenous α-syn in mice administered an intrastriatal injection of human α-syn PFF. MethodsWe inoculated human WT α-syn PFF in mouse striatum. At 6 weeks post PFF injection, we challenged the animal with two different doses of MPTP (10 mg/kg.b.wt and 25 mg/kg.b.wt) once daily for five consecutive days. At 2 weeks from the start of the MPTP regimen, we collected the mice brain and performed immunohistochemical analysis, and Rotarod test to assess motor coordination and muscle strength before and after MPTP injection. ResultsA single injection of human WT α-syn PFF in the mice striatum induced the propagation of α-syn, occurring as phosphorylated α-synuclein (pS129), towards the SNpc, within a very short time. Injection of a low dose of MPTP (10 mg/kg.b.wt) at 6 weeks post α-syn PFF inoculation further enhanced the spread, whereas a high dose of MPTP (25 mg/kg.b.wt.) reduced the spread. Majority of the accumulated α-syn were proteinase K resistant, as recognized using a conformation-specific α-syn antibody. Injection of α-syn PFF alone caused 12 % reduction in the number of tyrosine hydroxylase positive neurons while α-syn PFF + a low dose of MPTP caused 33 % reduction (loss), compared to the control mice injected with saline. This combination also reduced the motor coordination. Interestingly, a low dose of MPTP alone did not cause any significant reduction in the number of tyrosine hydroxylase positive neurons compared to saline treatment. Animals that received α-syn PFF and a high dose of MPTP showed massive activation of glial cells and decreased spread of α-syn, majority of which were detected in the nucleus. ConclusionOur results suggest that a combination of human WT α-syn PFF and a low dose of MPTP increases the pathological conversion and propagation of endogenous α-syn, and neurodegeneration, within a very short time. Our model can be used to study the mechanisms of α-syn propagation and screen for potential drugs against PD.

Gut microbiota-derived propionate mediates the neuroprotective effect of osteocalcin in a mouse model of Parkinson’s disease

BackgroundParkinson’s disease (PD) is a neurodegenerative disorder with no absolute cure. The evidence of the involvement of gut microbiota in PD pathogenesis suggests the need to identify certain molecule(s) derived from the gut microbiota, which has the potential to manage PD. Osteocalcin (OCN), an osteoblast-secreted protein, has been shown to modulate brain function. Thus, it is of interest to investigate whether OCN could exert protective effect on PD and, if yes, whether the underlying mechanism lies in the subsequent changes in gut microbiota.ResultsThe intraperitoneal injection of OCN can effectively ameliorate the motor deficits and dopaminergic neuronal loss in a 6-hydroxydopamine-induced PD mouse model. The further antibiotics treatment and fecal microbiota transplantation experiments confirmed that the gut microbiota was required for OCN-induced protection in PD mice. OCN elevated Bacteroidetes and depleted Firmicutes phyla in the gut microbiota of PD mice with elevated potential of microbial propionate production and was confirmed by fecal propionate levels. Two months of orally administered propionate successfully rescued motor deficits and dopaminergic neuronal loss in PD mice. Furthermore, AR420626, the agonist of FFAR3, which is the receptor of propionate, mimicked the neuroprotective effects of propionate and the ablation of enteric neurons blocked the prevention of dopaminergic neuronal loss by propionate in PD mice.ConclusionsTogether, our results demonstrate that OCN ameliorates motor deficits and dopaminergic neuronal loss in PD mice, modulating gut microbiome and increasing propionate level might be an underlying mechanism responsible for the neuroprotective effects of OCN on PD, and the FFAR3, expressed in enteric nervous system, might be the main action site of propionate.CoKvBsES-WQ_2hkhyhEj9XVideo abstract

Neuroprotective and Neurorestorative Effects of Holothuria scabra Extract in the MPTP/MPP+-Induced Mouse and Cellular Models of Parkinson’s Disease

Extracts from Holothuria scabra (HS) have been shown to possess anti-inflammation, anti-oxidant and anti-cancer activities. More recently, it was shown to have neuroprotective potential in Caenorhabditis elegans PD model. Here, we assessed whether HS has neuroprotective and neurorestorative effects on dopaminergic neurons in both mouse and cellular models of PD. We found that both pre-treatment and post-treatment with HS improved motor deficits in PD mouse model induced with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as determined by grid walk test. This was likely mediated by HS protective and restorative effects on maintaining the numbers of dopaminergic neurons and fibers in both substantia nigra pars compacta (SNpc) and striatum. In a cellular model of PD, HS significantly attenuated 1-methyl-4-phenylpyridinium (MPP+)-induced apoptosis of DAergic-like neurons differentiated from SH-SY5Y cells by enhancing the expression of Bcl-2, suppressing the expression of cleaved Caspase 3 and preventing depolarization of mitochondrial membrane. In addition, HS could stimulate the expression of tyrosine hydroxylase (TH) and suppressed the formation of α-synuclein protein. Taken together, our in vivo and in vitro findings suggested that HS is an attractive candidate for the neuroprotection rather than neurorestoration in PD.

Inflammatory lncRNA AK039862 regulates paraquat-inhibited proliferation and migration of microglial and neuronal cells through the Pafah1b1/Foxa1 pathway in co-culture environments

Emerging evidences having suggested that particular lncRNAs have a potential effect on PD progression through provoking damage and inflammatory responses of microglia/ dopaminergic cells. In addition, paraquat can be accumulated in human body through various approaches and have an increased risk for Parkinson’s disease. However, the specific role and mechanism of lncRNA related to neurotoxic in the progression of PD is unclear. In our study, a mouse PD model was established induced by the intraperitoneal injection of paraquat (5 mg/kg and 10 mg/kg) every three days (10 times). We determined differential expression of lncRNA AK039862 and its potential targeted genes Pafah1b1/Foxa1 in PD mouse model, then we used fluorescence in situ hybridization (FISH) to visualize the cellular distribution of AK039862. Short interfering RNAs (siRNAs) and overexpression plasmids were designed for knockdown or overexpression of AK039862. To simulate the coexisting dopaminergic cells and microglia cells in vitro, we applied several non-contact co-culture models, including conditioned medium and Transwell co-culture systems. Cytotoxicity of PQ was evaluated using bv2 cells with the concentrations: 30, 60 μM, and mn9d cells with the concentrations: 50, 100 μM. As a result, we depicted multiple interesting individual and interactive features of inflammatory lncRNA AK039862 involved in PQ-induced cellular functional effects. First, we detected that AK039862 contributed to the neuronal injury process in PQ-treated mice and co-localization of AK039862 with dopaminergic cells in vivo. And interestingly, we demonstrated that PQ significantly inhibited microglia and dopaminergic cells proliferation and microglia migration in vitro. Further research indicated that the PQ-induced low expression of AK039862 rescued microglia proliferation and migration inhibition via the AK039862/Pafah1b1/Foxa1 pathway. Meanwhile, AK039862 also participated in the interaction between microglia and dopaminergic cells with PQ treatment in non-contact co-culture models. In summary, we found that PQ inhibited the proliferation and migration of microglial cells, and elucidated AK039862 played a key role in PQ-induced neuroinflammatory damage through Pafah1b1/Foxa1. Finally, inflammatory AK039862 is involved in the complex communication between microglia and dopaminergic cells in the environment of PQ damage.

MiR-103a-3p regulates mitophagy in Parkinson’s disease through Parkin/Ambra1 signaling

Parkin is a crucial protein that promotes the clearance of damaged mitochondria via mitophagy in neuron, and parkin mutations result in autosomal-recessive Parkinson’s disease (AR-PD). However, the exact mechanisms underlying the regulation of Parkin-mediated mitophagy in PD remain unclear. In this study, PD models were generated through incubation of SH-SY5Y cells with 1-methyl-4-phenylpyridinium ion (MPP+, 1.5 mM for 24 h) and intraperitoneal injections of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg for five consecutive days) in mice. A Bioinformatics database was used to identify Parkin-targeting microRNAs (miRNAs). Then, miR-103a-3p agomir, miR-103a-3p antagomir and Parkin siRNA were used to assess the effects of miR-103a-3p/Parkin/Ambra1 signaling-mediated mitophagy in PD in vitro and in vivo. The protein and mRNA levels of Parkin and Ambra1 were significantly decreased, while miR-103a-3p, which is a highly expressed miRNA in the human brain, was obviously increased in PD mouse and SH-SY5Y cell models. Moreover, miR-103a-3p suppressed Parkin expression by targeting a conserved binding site in the 3'-untranslated region (UTR) of Parkin mRNA. Importantly, miR-103a-3p inhibition resulted in neuroprotective effects and improved mitophagy in vitro and in vivo, whereas Parkin siRNA strongly abolished these effects. These findings suggested that miR-103a-3p inhibition has neuroprotective effects in PD, which may be involved in regulating mitophagy through the Parkin/Ambra1 pathway. Modulating miR-103a-3p levels may be an applicable therapeutic strategy for PD.

NLRP3 inflammasome inhibitor MCC950 attenuates primary dysmenorrhea in mice via the NF-\u03baB/COX-2/PG pathway

BackgroundPrimary dysmenorrhea (PD) constitutes a common gynecological disease among young women. The NLRP3 inflammasome may be activated and expressed in PD, but the mechanistic link between NLRP3 inflammasome activation and PD is still unclear.MethodsTo investigate the potential role of NLRP3 inflammasome activation in the pathogenesis of PD, 30 female Kunming mice without pregnancy were used for experiments. The PD mouse model was constructed by 11 days of successive co-treatment with estradiol and oxytocin. MCC950, a potent and specific small-molecule inhibitor of the NLRP3 inflammasome, was used to treat PD mice. The disease level was assessed by the writhing response and hot water tail-flick test. The levels of prostaglandin E2 (PGE2) and prostaglandin F2 alpha (PGF2α) in the uterine tissues of mice were detected by ELISA. The expression levels of protein and cytokines, including NLRP3, cysteine aspartic acid-specific protease 1 (caspase-1), interleukin (IL)-1β, IL-18, nuclear factor kappa B (NF-κB) p65, phospho-NF-κB p65, and cyclooxygenase-2 (COX-2) were revealed by western blot analysis.ResultsMCC950 greatly ameliorated the writhing response induced by the combination of oxytocin and estradiol, with an increasing length of tail-flick latency. MCC950 also significantly decreased the levels of PGF2α and PGE2, and the expressions of NLRP3, caspase-1, IL-1β, IL-18, phospho-NF-κB p65, NF-κB p65, and COX-2 in the uterus.ConclusionsMCC950 markedly alleviated the pain and pathological damage in PD mice by inhibiting NLRP3 activation. The underlying mechanism may be related to hypoactive uterine inflammation via suppression of NLRP3 activation and the NF-κB/COX-2/PG pathway in uteruses of PD mice.

Rg1 improves LPS-induced Parkinsonian symptoms in mice via inhibition of NF-κB signaling and modulation of M1/M2 polarization.

Ginsenoside Rg1 is one of the most active ingredients in ginseng, which has been reported to protect dopaminergic neurons and improve behavioral defects in MPTP model, 6-OHDA model and rotenone model. However, it is unclear whether Rg1 exerted neuroprotection in LPS-induced sub-acute PD model. In this study, we investigated the neuroprotective effect of Rg1 in the sub-acute PD mouse model and explored the related mechanisms. Rg1 (10, 20, 40 mg·kg−1·d−1) was orally administered to mice for 18 days. A sub-acute PD model was established in the mice through LPS microinjection into the substantia nigra (SN) from D8 to D13. We found that Rg1 administration dose-dependently inhibited LPS-induced damage of dopaminergic neurons and activation of glial cells in the substantia nigra pars compacta (SNpc). The neuroprotective effects of Rg1 were associated with the reduction of pro-inflammatory cytokines and the improvement of anti-inflammatory cytokines and neurotrophin in the midbrain. Rg1 shifted the polarization of microglia towards the M2 phenotype from M1, evidenced by decreased M1 markers (inducible NO synthase, CD16, etc.) and increased M2 markers (arginase 1 (Arg1), CD206, etc) in the midbrain. Furthermore, Rg1 administration markedly inhibited nuclear translocation of NF-κB in midbrain microglia. In conclusion, Rg1 protects PD mice induced by continuous LPS injection by inhibiting the nuclear entry of NF-κB and regulating the polarization balance of microglia, shedding new light on a disease-modifying therapy of PD.

Focused ultrasound enhanced intranasal delivery of brain derived neurotrophic factor produces neurorestorative effects in a Parkinson\u2019s disease mouse model

Focused ultrasound-enhanced intranasal (IN + FUS) delivery is a noninvasive approach that utilizes the olfactory pathway to administer pharmacological agents directly to the brain, allowing for a more homogenous distribution in targeted locations compared to IN delivery alone. However, whether such a strategy has therapeutic values, especially in neurodegenerative disorders such as Parkinson’s disease (PD), remains to be established. Herein, we evaluated whether the expression of tyrosine hydroxylase (TH), the rate limiting enzyme in dopamine catalysis, could be enhanced by IN + FUS delivery of brain-derived neurotrophic factor (BDNF) in a toxin-based PD mouse model. Mice were put on the subacute dosing regimen of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), producing bilateral degeneration of the nigrostriatal pathway consistent with early-stage PD. MPTP mice then received BDNF intranasally followed by multiple unilateral FUS-induced blood-brain barrier (BBB) openings in the left basal ganglia for three consecutive weeks. Subsequently, mice were survived for two months and were evaluated morphologically and behaviorally to determine the integrity of their nigrostriatal dopaminergic pathways. Mice receiving IN + FUS had significantly increased TH immunoreactivity in the treated hemisphere compared to the untreated hemisphere while mice receiving only FUS-induced BBB opening or no treatment at all did not show any differences. Additionally, behavioral changes were only observed in the IN + FUS treated mice, indicating improved motor control function in the treated hemisphere. These findings demonstrate the robustness of the method and potential of IN + FUS for the delivery of bioactive factors for treatment of neurodegenerative disorder.

ROCK1 induces dopaminergic nerve cell apoptosis via the activation of Drp1-mediated aberrant mitochondrial fission in Parkinson\u2019s disease

Dopamine deficiency is mainly caused by apoptosis of dopaminergic nerve cells in the substantia nigra of the midbrain and the striatum and is an important pathologic basis of Parkinson’s disease (PD). Recent research has shown that dynamin-related protein 1 (Drp1)-mediated aberrant mitochondrial fission plays a crucial role in dopaminergic nerve cell apoptosis. However, the upstream regulatory mechanism remains unclear. Our study showed that Drp1 knockdown inhibited aberrant mitochondrial fission and apoptosis. Importantly, we found that ROCK1 was activated in an MPP+-induced PD cell model and that ROCK1 knockdown and the specific ROCK1 activation inhibitor Y-27632 blocked Drp1-mediated aberrant mitochondrial fission and apoptosis of dopaminergic nerve cells by suppressing Drp1 dephosphorylation/activation. Our in vivo study confirmed that Y-27632 significantly improved symptoms in a PD mouse model by inhibiting Drp1-mediated aberrant mitochondrial fission and apoptosis. Collectively, our findings suggest an important molecular mechanism of PD pathogenesis involving ROCK1-regulated dopaminergic nerve cell apoptosis via the activation of Drp1-induced aberrant mitochondrial fission.