Activated astrocytes enhance the dopaminergic differentiation of stem cells and promote brain repair through bFGF

Unleashing light's healing power: an overview of photobiomodulation for Alzheimer's treatment

Aim: Photobiomodulation involves the use of low-level light therapy or near-infrared light therapy found to be useful in the treatment of a wide range of neurological diseases. Objective: The aim is to review the mechanism and clinical applications of photobiomodulation therapy (PBMT) in managing Alzheimer's disease. Methods: To ensure that the consensus statement accurately reflects both the experts' viewpoint and the most recent developments in the field, the expert opinions were recorded and thoroughly reviewed. Results: PBMT elicits reduction of beta-amyloid plaque, restoration of mitochondrial function, anti-inflammatory and antioxidant properties with a stimulation in ATP synthesis. Conclusion: The PBMT could be helpful in patients non-responsive to traditional pharmacological therapy providing significant aid in the management of Alzheimer's disease when introduced into the medical field.

Mechanistic study of the anti-excitatory amino acid toxicity of Bushen Zhichan decoction for Parkinson's disease based on the transcriptional regulation of EAAT1 by YY1

ETHNOPHARMACOLOGICAL RELEVANCE

Bushen Zhichan decoction (BSZCF) is derived from Liuwei Dihuang Pill, a famous Chinese herbal formula recorded in the book Key to Therapeutics of Children's Diseases. It has been widely used as a basic prescription for nourishing and tonifying the liver and kidneys to treat Parkinson's disease (PD), but its mechanism remains to be explored.

AIM OF THE STUDY

BSZCF, a Chinese herbal formula comprising five herbs: Rehmannia glutinosa (Gaertn.) DC., Dioscorea oppositifolia L., Cornus officinalis Siebold & Zucc., Fallopia multiflora (Thunb.) Haraldson and Cistanche tubulosa (Schenk) Wight, is used clinically to treat PD. In vivo and in vitro experiments were designed to elucidate the mechanism of BSZCF in the protection of dopamine (DA) neurons and the treatment of PD. The toxicity of excitatory amino acids (EAA) may be attenuated by inhibiting the transcription factor Yin Yang 1 (YY1) and up-regulating the expression of excitatory amino acid transporter 1 (EAAT1).

MATERIALS AND METHODS

IN VIVO: After 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was intraperitoneally injected into specific pathogen free (SPF) C57BL/6J mice, model mice were intragastrically given adamantane hydrochloride tablets (AHT) or different doses of BSZCF for 14 days. Both open field and pole-climbing tests were conducted to assess behavioral changes. In vitro: 1-Methyl-4-phe-nylpyridiniumiodide (MPP+)-injured human neuroblastoma cells (SH-SY5Y) were utilized to construct PD cell models. Primary astrocytes were transfected with EAAT1 and YY1 lentiviruses for EAAT1 gene knockout and YY1 gene knockout astrocytes, respectively. The high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis of BSZCF was performed to control the quality of blood drugs. The optimal concentration and time of PD cell models treated by BSZCF were determined by the use of Cell Counting Kit-8 (CCK8). Enzyme-linked immunosorbent assay (ELISA) was used for measuring glutamate (Glu) in the peripheral blood and cells of each group. Western blotting (WB) and real-time quantitative polymerase chain reaction (qPCR) were used to detect tyrosine hydroxylase (TH), dopamine transporters (DAT), EAAT1 and YY1 protein and mRNA. After the blockade of EAAT1, immunofluorescence (IF) assay was used to detect the TH protein in each group.

RESULTS

In vivo research showed that BSZCF improved the behavioral symptoms of PD mice, and reduced the death of DA neurons and the level of Glu. The mechanism may be related to the decrease of YY1 expression and the increase of EAAT1 levels. In vitro experiments showed that the anti-excitatory amino acid toxicity of BSZCF was achieved by inhibiting YY1 expression and regulating EAAT1.

CONCLUSIONS

By inhibiting YY1 to increase the expression of EAAT1 and attenuating the toxicity of Glu, BSZCF exerts the effect of protecting DA neurons and treating PD-like symptoms in mice.

Kinetic Properties and Pharmacological Modulation of High- and Low-Affinity Dopamine Transport in Striatal Astrocytes of Adult Rats

Astrocytes actively participate in neurotransmitter homeostasis by bidirectional communication with neuronal cells, a concept named the tripartite synapse, yet their role in dopamine (DA) homeostasis remains understudied. In the present study, we investigated the kinetic and molecular mechanisms of DA transport in cultured striatal astrocytes of adult rats. Kinetic uptake experiments were performed using radiolabeled [3H]-DA, whereas mRNA expression of the dopamine, norepinephrine, organic cation and plasma membrane monoamine transporters (DAT, NET, OCTs and PMAT) and DA receptors D1 and D2 was determined by qPCR. Additionally, astrocyte cultures were subjected to a 24 h treatment with the DA receptor agonist apomorphine, the DA receptor antagonist haloperidol and the DA precursor L-DOPA. [3H]-DA uptake exhibited temperature, concentration and sodium dependence, with potent inhibition by desipramine, nortriptyline and decynium-22, suggesting the involvement of multiple transporters. qPCR revealed prominent mRNA expression of the NET, the PMAT and OCT1, alongside lower levels of mRNA for OCT2, OCT3 and the DAT. Notably, apomorphine significantly altered NET, PMAT and D1 mRNA expression, while haloperidol and L-DOPA had a modest impact. Our findings demonstrate that striatal astrocytes aid in DA clearance by multiple transporters, which are influenced by dopaminergic drugs. Our study enhances the understanding of regional DA uptake, paving the way for targeted therapeutic interventions in dopaminergic disorders.

Possible role of lncRNAs in amelioration of Parkinson's disease symptoms by transplantation of dopaminergic cells

Long non-coding RNAs (lncRNAs) are biomarkers for diagnosis and treatment of Parkinson's disease (PD). Since dopaminergic cell transplantation is a clinical method to treat PD, this study investigated the effects of dopaminergic cell therapy on the expression of some lncRNAs and genes related to PD. In this study, Twenty-eight rats were randomly assigned to four experimental groups. The control group (Sal group) received saline injections. The Par group was a PD rat model with 6-hydroxydopamine (6-OHDA) injection in right striatum (ST). PD animals were transplanted by undifferentiated P19 stem cells (Par-E group), and P19-derived dopaminergic cells (Par-N group). Cell transplant effects were evaluated using behavioral tests (cylinder, open field, and rotarod tests), and histological methods (H&E and Nissl staining, and immunohistochemistry). Moreover, the expression of lncRNAs MALAT1, MEG3, and SNHG1, alongside specific neuronal (synaptophysin) and dopaminergic (tyrosine hydroxylase) markers was evaluated by qRT-PCR. Behavioral and histopathological examinations revealed that cell transplantation partially compensated dopaminergic cell degeneration in ST and substantia nigra (SN) of PD rats. The expression of MALAT1, SNHG1, and MEG3 was decreased in the ST of the Par group, while MEG3 and SNHG1 gene expression was increased in PBMC relative to the Sal group. In PBMC of the Par-N group, all three lncRNAs showed a reduction in their expression. Conversely, MALAT1 and SNHG1 expression was increased in ST tissue, while MEG3 gene expression was decreased compared to the Sal group. In conclusion, dopaminergic cell transplantation could change the lncRNAs expression. Furthermore, it partially improves symptoms in PD rats.

Cortical and Striatal Astrocytes of Neonatal Rats Display Distinct Molecular and Pharmacological Characteristics of Dopamine Uptake

Astrocytes are crucial in the regulation of neurotransmitter homeostasis, and while their involvement in the dopamine (DA) tripartite synapse is acknowledged, it necessitates a more comprehensive investigation. In the present study, experiments were conducted on primary astrocyte cultures from the striatum and cortex of neonatal rats. The pharmacological intricacies of DA uptake, including dependence on time, temperature, and concentration, were investigated using radiolabelled [3H]-DA. The mRNA expression of transporters DAT, NET, PMAT, and OCTs was evaluated by qPCR. Notably, astrocytes from both brain regions exhibited prominent mRNA expression of NET and PMAT, with comparatively lower expression of DAT and OCTs. The inhibition of DA uptake by the DAT inhibitor, GBR12909, and NET inhibitors, desipramine and nortriptyline, impeded DA uptake in striatal astrocytes more than in cortical astrocytes. The mRNA expression of NET and PMAT was significantly upregulated in cortical astrocytes in response to the DA receptor agonist apomorphine, while only the mRNA expression of NET exhibited changes in striatal astrocytes. Haloperidol, a DA receptor antagonist, and L-DOPA, a DA precursor, did not induce significant alterations in transporter mRNA expression. These findings underscore the intricate and region-specific mechanisms governing DA uptake in astrocytes, emphasizing the need for continued exploration to unravel the nuanced dynamics of astrocytic involvement in the DA tripartite synapse.

Investigation of a UPR-Related Gene Signature Identifies the Pro-Fibrotic Effects of Thrombospondin-1 by Activating CD47/ROS/Endoplasmic Reticulum Stress Pathway in Lung Fibroblasts

Unfolded protein response (UPR) signaling and endoplasmic reticulum (ER) stress have been linked to pulmonary fibrosis. However, the relationship between UPR status and pulmonary function and prognosis in idiopathic pulmonary fibrosis (IPF) patients remains largely unknown. Through a series of bioinformatics analyses, we established a correlation between UPR status and pulmonary function in IPF patients. Furthermore, thrombospondin-1 (TSP-1) was identified as a potential biomarker for prognostic evaluation in IPF patients. By utilizing both bulk RNA profiling and single-cell RNA sequencing data, we demonstrated the upregulation of TSP-1 in lung fibroblasts during pulmonary fibrosis. Gene set enrichment analysis (GSEA) results indicated a positive association between TSP-1 expression and gene sets related to the reactive oxygen species (ROS) pathway in lung fibroblasts. TSP-1 overexpression alone induced mild ER stress and pulmonary fibrosis, and it even exacerbated bleomycin-induced ER stress and pulmonary fibrosis. Mechanistically, TSP-1 promoted ER stress and fibroblast activation through CD47-dependent ROS production. Treatment with either TSP-1 inhibitor or CD47 inhibitor significantly attenuated BLM-induced ER stress and pulmonary fibrosis. Collectively, these findings suggest that the elevation of TSP-1 during pulmonary fibrosis is not merely a biomarker but likely plays a pathogenic role in the fibrotic changes in the lung.

Optogenetic Activation of Astrocytes Reduces Blood-Brain Barrier Disruption via IL-10 In Stroke

Optogenetics has been used to regulate astrocyte activity and modulate neuronal function after brain injury. Activated astrocytes regulate blood-brain barrier functions and are thereby involved in brain repair. However, the effect and molecular mechanism of optogenetic-activated astrocytes on the change in barrier function in ischemic stroke remain obscure. In this study, adult male GFAP-ChR2-EYFP transgenic Sprague-Dawley rats were stimulated by optogenetics at 24, 36, 48, and 60 h after photothrombotic stroke to activate ipsilateral cortical astrocytes. The effects of activated astrocytes on barrier integrity and the underlying mechanisms were explored using immunostaining, western blotting, RT-qPCR, and shRNA interference. Neurobehavioral tests were performed to evaluate therapeutic efficacy. The results demonstrated that IgG leakage, gap formation of tight junction proteins, and matrix metallopeptidase 2 expression were reduced after optogenetic activation of astrocytes (p<0.05). Moreover, photo-stimulation of astrocytes protected neurons against apoptosis and improved neurobehavioral outcomes in stroke rats compared to controls (p<0.05). Notably, interleukin-10 expression in optogenetic-activated astrocytes significantly increased after ischemic stroke in rats. Inhibition of interleukin-10 in astrocytes compromised the protective effects of optogenetic-activated astrocytes (p<0.05). We found for the first time that interleukin-10 derived from optogenetic-activated astrocytes protected blood-brain barrier integrity by decreasing the activity of matrix metallopeptidase 2 and attenuated neuronal apoptosis, which provided a novel therapeutic approach and target in the acute stage of ischemic stroke.

Fibroblast Upregulation of Vitamin D Receptor Represents a Self-Protective Response to Limit Fibroblast Proliferation and Activation during Pulmonary Fibrosis

Dysregulation of vitamin D receptor (VDR) is implicated in chronic obstructive pulmonary disease. However, whether VDR dysregulation contributes to the development of pulmonary fibrosis remains largely unknown. Analysis of bulk and single-cell RNA profiling datasets revealed VDR upregulation in lung fibroblasts from patients with pulmonary fibrosis or fibrotic mice, which was validated in lung fibroblasts from bleomycin-exposed mice and bleomycin-treated fibroblasts. Stable VDR knockdown promoted, whereas the VDR agonist paricalcitol suppressed lung fibroblast proliferation and activation. Gene set enrichment analysis (GSEA) showed that the JAK/STAT pathway and unfolded protein response (UPR), a process related to endoplasmic reticulum (ER) stress, were enriched in lung fibroblasts of fibrotic lungs. Stable VDR knockdown stimulated, but paricalcitol suppressed ER stress and JAK1/STAT3 activation in lung fibroblasts. The STAT3 inhibitor blocked bleomycin- or stable VDR knockdown-induced ER stress. Paricalcitol inhibited the bleomycin-induced enrichment of STAT3 to the ATF6 promoter, thereby suppressing ATF6 expression in fibroblasts. Paricalcitol or intrapulmonary VDR overexpression inactivated JAK1/STAT3 and suppressed ER stress in bleomycin-treated mice, thus resulting in the inhibition of fibroblast proliferation and activation. Collectively, this study suggests that fibroblast VDR upregulation may be a self-protective response to limit fibroblast proliferation and activation during pulmonary fibrosis by suppressing the JAK1/STAT3/ER stress pathway.

Probabilistic cell seeding and non-autofluorescent 3D-printed structures as scalable approach for multi-level co-culture modeling

To model complex biological tissue in vitro, a specific layout for the position and numbers of each cell type is necessary. Establishing such a layout requires manual cell placement in three dimensions (3D) with micrometric precision, which is complicated and time-consuming. Moreover, 3D printed materials used in compartmentalized microfluidic models are opaque or autofluorescent, hindering parallel optical readout and forcing serial characterization methods, such as patch-clamp probing. To address these limitations, we introduce a multi-level co-culture model realized using a parallel cell seeding strategy of human neurons and astrocytes on 3D structures printed with a commercially available non-autofluorescent resin at micrometer resolution. Using a two-step strategy based on probabilistic cell seeding, we demonstrate a human neuronal monoculture that forms networks on the 3D printed structure and can establish cell-projection contacts with an astrocytic-neuronal co-culture seeded on the glass substrate. The transparent and non-autofluorescent printed platform allows fluorescence-based immunocytochemistry and calcium imaging. This approach provides facile multi-level compartmentalization of different cell types and routes for pre-designed cell projection contacts, instrumental in studying complex tissue, such as the human brain.

From 2D to 3D: Development of Monolayer Dopaminergic Neuronal and Midbrain Organoid Cultures for Parkinson's Disease Modeling and Regenerative Therapy

Parkinson's Disease (PD) is a prevalent neurodegenerative disorder that is characterized pathologically by the loss of A9-specific dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) of the midbrain. Despite intensive research, the etiology of PD is currently unresolved, and the disease remains incurable. This, in part, is due to the lack of an experimental disease model that could faithfully recapitulate the features of human PD. However, the recent advent of induced pluripotent stem cell (iPSC) technology has allowed PD models to be created from patient-derived cells. Indeed, DA neurons from PD patients are now routinely established in many laboratories as monolayers as well as 3D organoid cultures that serve as useful toolboxes for understanding the mechanism underlying PD and also for drug discovery. At the same time, the iPSC technology also provides unprecedented opportunity for autologous cell-based therapy for the PD patient to be performed using the patient's own cells as starting materials. In this review, we provide an update on the molecular processes underpinning the development and differentiation of human pluripotent stem cells (PSCs) into midbrain DA neurons in both 2D and 3D cultures, as well as the latest advancements in using these cells for drug discovery and regenerative medicine. For the novice entering the field, the cornucopia of differentiation protocols reported for the generation of midbrain DA neurons may seem daunting. Here, we have distilled the essence of the different approaches and summarized the main factors driving DA neuronal differentiation, with the view to provide a useful guide to newcomers who are interested in developing iPSC-based models of PD.

Nucleus accumbens circuit disinhibits lateral hypothalamus glutamatergic neurons contributing to morphine withdrawal memory in male mice

The lateral hypothalamus (LH) is physiologically critical in brain functions. The LH also plays an important role in drug addiction. However, neural circuits underlying LH involvement of drug addiction remain obscure. In the present study,our results showed that in male mice, during context-induced expression of morphine withdrawal memory, LH glutamatergic neurons played an important role; dopamine D1 receptor-expressing medium spiny neurons (D1-MSNs) projecting from the core of nucleus accumbens (NAcC) to the LH were an important upstream circuit to activate LH glutamatergic neurons; D1-MSNs projecting from the NAcC to the LH activated LH glutamatergic neurons through inhibiting LH local gamma-aminobutyric acid (GABA) neurons. These results suggest that disinhibited LH glutamatergic neurons by neural circuits from the NAcC importantly contribute to context-induced the expression of morphine withdrawal memory.

Adrenergic signalling to astrocytes in anterior cingulate cortex contributes to pain-related aversive memory in rats

Pain contains both sensory and affective dimensions. We identify the role of norepinephrine in colorectal distention (sub-threshold for acute pain) induced conditioned place avoidance and plasticity gene expression in the anterior cingulate cortex (ACC). Activating locus coeruleus (LC)-projecting ACC neurons facilitates pain-evoked aversive consolidation and memory, while inhibiting LC-projecting ACC neurons reversibly blocks it. Optogenetic activation of ACC astrocytes facilitates aversive behaviour. ACC astrocytic Gi manipulation suppressed aversive behaviour and early plasticity gene expression induced by opto-activation of LC neurons projecting to ACC. Evidences for the critical role of β2AR in ACC astrocytes were provided using AAV encoding β2AR miRNAi to knockdown β2AR in astrocytes. In contrast, opto-activation of ACC astrocytic β2ARs promotes aversion memory. Our findings suggest that projection-specific adrenergic astrocytic signalling in ACC is integral to system-wide neuromodulation in response to visceral stimuli, and plays a key role in mediating pain-related aversion consolidation and memory formation.

In Utero Electroporation for Manipulation of Specific Neuronal Populations

The complexity of brain functions is supported by the heterogeneity of brain tissue and millisecond-scale information processing. Understanding how complex neural circuits control animal behavior requires the precise manipulation of specific neuronal subtypes at high spatiotemporal resolution. In utero electroporation, when combined with optogenetics, is a powerful method for precisely controlling the activity of specific neurons. Optogenetics allows for the control of cellular membrane potentials through light-sensitive ion channels artificially expressed in the plasma membrane of neurons. Here, we first review the basic mechanisms and characteristics of in utero electroporation. Then, we discuss recent applications of in utero electroporation combined with optogenetics to investigate the functions and characteristics of specific regions, layers, and cell types. These techniques will pave the way for further advances in understanding the complex neuronal and circuit mechanisms that underlie behavioral outputs.

Novel Approaches Used to Examine and Control Neurogenesis in Parkinson's Disease

Neurogenesis is a key mechanism of brain development and plasticity, which is impaired in chronic neurodegeneration, including Parkinson’s disease. The accumulation of aberrant α-synuclein is one of the features of PD. Being secreted, this protein produces a prominent neurotoxic effect, alters synaptic plasticity, deregulates intercellular communication, and supports the development of neuroinflammation, thereby providing propagation of pathological events leading to the establishment of a PD-specific phenotype. Multidirectional and ambiguous effects of α-synuclein on adult neurogenesis suggest that impaired neurogenesis should be considered as a target for the prevention of cell loss and restoration of neurological functions. Thus, stimulation of endogenous neurogenesis or cell-replacement therapy with stem cell-derived differentiated neurons raises new hopes for the development of effective and safe technologies for treating PD neurodegeneration. Given the rapid development of optogenetics, it is not surprising that this method has already been repeatedly tested in manipulating neurogenesis in vivo and in vitro via targeting stem or progenitor cells. However, niche astrocytes could also serve as promising candidates for controlling neuronal differentiation and improving the functional integration of newly formed neurons within the brain tissue. In this review, we mainly focus on current approaches to assess neurogenesis and prospects in the application of optogenetic protocols to restore the neurogenesis in Parkinson’s disease.

Astrocytes in the Ventromedial Hypothalamus Involve Chronic Stress-Induced Anxiety and Bone Loss in Mice

Chronic stress is one of the main risk factors of bone loss. While the neurons and neural circuits of the ventromedial hypothalamus (VMH) mediate bone loss induced by chronic stress, the detailed intrinsic mechanisms within the VMH nucleus still need to be explored. Astrocytes in brain regions play important roles in the regulation of metabolism and anxiety-like behavior through interactions with surrounding neurons. However, whether astrocytes in the VMH affect neuronal activity and therefore regulate chronic stress-induced anxiety and bone loss remain elusive. In this study, we found that VMH astrocytes were activated during chronic stress-induced anxiety and bone loss. Pharmacogenetic activation of the Gi and Gq pathways in VMH astrocytes reduced and increased the levels of anxiety and bone loss, respectively. Furthermore, activation of VMH astrocytes by optogenetics induced depolarization in neighboring steroidogenic factor-1 (SF-1) neurons, which was diminished by administration of N-methyl-D-aspartic acid (NMDA) receptor blocker but not by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor blocker. These results suggest that there may be a functional "glial-neuron microcircuit" in VMH nuclei that mediates anxiety and bone loss induced by chronic stress. This study not only advances our understanding of glial cell function but also provides a potential intervention target for chronic stress-induced anxiety and bone loss therapy.

FGF, Mechanism of Action, Role in Parkinson's Disease, and Therapeutics

Parkinson's disease (PD) is a neurodegenerative disease associated with severe disability and adverse effects on life quality. In PD, motor dysfunction can occur, such as quiescence, muscle stiffness, and postural instability. PD is also associated with autonomic nervous dysfunction, sleep disorders, psychiatric symptoms, and other non-motor symptoms. Degeneration of dopaminergic neurons in the substantia nigra compact (SNPC), Lewy body, and neuroinflammation are the main pathological features of PD. The death or dysfunction of dopaminergic neurons in the dense part of the substantia nigra leads to dopamine deficiency in the basal ganglia and motor dysfunction. The formation of the Lewy body is associated with the misfolding of α-synuclein, which becomes insoluble and abnormally aggregated. Astrocytes and microglia mainly cause neuroinflammation, and the activation of a variety of pro-inflammatory transcription factors and regulatory proteins leads to the degeneration of dopaminergic neurons. At present, PD is mainly treated with drugs that increase dopamine concentration or directly stimulate dopamine receptors. Fibroblast growth factor (FGF) is a family of cellular signaling proteins strongly associated with neurodegenerative diseases such as PD. FGF and its receptor (FGFR) play an essential role in the development and maintenance of the nervous system as well as in neuroinflammation and have been shown to improve the survival rate of dopaminergic neurons. This paper summarized the mechanism of FGF and its receptors in the pathological process of PD and related signaling pathways, involving the development and protection of dopaminergic neurons in SNPC, α-synuclein aggregation, mitochondrial dysfunction, and neuroinflammation. It provides a reference for developing drugs to slow down or prevent the potential of PD.

Neural stem cells derived from human midbrain organoids as a stable source for treating Parkinson's disease: Midbrain organoid-NSCs (Og-NSC) as a stable source for PD treatment

Successful clinical translation of stem cell-based therapy largely relies on the scalable and reproducible preparation of donor cells with potent therapeutic capacities. In this study, midbrain organoids were yielded from human pluripotent stem cells (hPSCs) to prepare cells for Parkinson's disease (PD) therapy. Neural stem/precursor cells (NSCs) isolated from midbrain organoids (Og-NSCs) expanded stably and differentiated into midbrain-type dopamine(mDA) neurons, and an unprecedentedly high proportion expressed midbrain-specific factors, with relatively low cell line and batch-to-batch variations. Single cell transcriptome analysis followed by in vitro assays indicated that the majority of cells in the Og-NSC cultures are ventral midbrain (VM)-patterned with low levels of cellular senescence/aging and mitochondrial stress, compared to those derived from 2D-culture environments. Notably, in contrast to current methods yielding mDA neurons without astrocyte differentiation, mDA neurons that differentiated from Og-NSCs were interspersed with astrocytes as in the physiologic brain environment. Thus, the Og-NSC-derived mDA neurons exhibited improved synaptic maturity, functionality, resistance to toxic insults, and faithful expressions of the midbrain-specific factors, in vitro and in vivo long after transplantation. Consequently, Og-NSC transplantation yielded potent therapeutic outcomes that are reproducible in PD model animals. Collectively, our observations demonstrate that the organoid-based method may satisfy the demands needed in the clinical setting of PD cell therapy.

Effect of TO901317 on GF to promote the differentiation of human bone marrow mesenchymal stem cells into dopamine neurons on Parkinson's disease

Background:

Human bone marrow mesenchymal stem cells (hBMSCs) could differentiate into dopamine-producing cells and ameliorate behavioral deficits in Parkinson’s disease (PD) models. Liver X receptors (LXRs) are involved in the maintenance of the normal function of central nervous system myelin. Therefore, the previous work of our team has found the induction of cocktail-induced to dopaminergic (DA) phenotypes from adult rat BMSCs by using sonic hedgehog (SHH), fibroblast growth factor 8 (FGF8), basic fibroblast growth factor (bFGF), and TO901317 (an agonist of LXRs) with 87.42% of efficiency in a 6-day induction period. But we did not verify whether the induced cells had the corresponding neural function.

Methods:

Expressions of LXRα, LXRβ, and tyrosine hydroxylase (TH) were detected by immunofluorescence and western blot. Adenosine triphosphate-binding cassette transporter A1 (ABCA1) was detected by quantitative real-time PCR. The induced cells were transplanted into PD rats to study whether the induced cells are working.

Results:

The induced cells can release the dopamine transmitter; the maximum induction efficiency of differentiation of hBMSCs into DA neurons was 91.67% under conditions of combined use with TO901317 and growth factors (GF). When the induced-cells were transplanted into PD rats, the expression of TH in the striatum increased significantly, and the behavior of PD rats induced by apomorphine was significantly improved.

Conclusion:

The induced cells have the function of DA neurons and have the potential to treat PD. TO901317 promoted differentiation of hBMSCs into DA neurons, which may be related to activation of the LXR-ABCA1 signaling pathway.

Enhanced differentiation of human induced pluripotent stem cells toward the midbrain dopaminergic neuron lineage through GLYPICAN-4 downregulation

Enhancing the differentiation potential of human induced pluripotent stem cells (hiPSC) into disease‐relevant cell types is instrumental for their widespread application in medicine. Here, we show that hiPSCs downregulated for the signaling modulator GLYPICAN‐4 (GPC4) acquire a new biological state characterized by increased hiPSC differentiation capabilities toward ventral midbrain dopaminergic (VMDA) neuron progenitors. This biological trait emerges both in vitro, upon exposing cells to VMDA neuronal differentiation signals, and in vivo, even when transplanting hiPSCs at the extreme conditions of floor‐plate stage in rat brains. Moreover, it is compatible with the overall neuronal maturation process toward acquisition of substantia nigra neuron identity. HiPSCs with downregulated GPC4 also retain self‐renewal and pluripotency in stemness conditions, in vitro, while losing tumorigenesis in vivo as assessed by flank xenografts. In conclusion, our results highlight GPC4 downregulation as a powerful approach to enhance generation of VMDA neurons. Outcomes may contribute to establish hiPSC lines suitable for translational applications.

Chronic optogenetic manipulation of basolateral amygdala astrocytes rescues stress-induced anxiety

Chronic exposure to stressors can disrupt normal brain function and induce anxiety-like behavior and neurobiological alterations in the basolateral amygdala (BLA). Here, we showed that unpredictable chronic mild stress (UCMS) induced anxiety-like behavior, lowered glutamatergic neuronal activity and reactive astrocytes in the BLA. Using optogenetic tools, we found that activation of BLA glutamatergic neurons did not rescue anxiety-like behavior in stressed mice. In contrast, however, optogenetic activation of the BLA astrocytes relieved stress-induced anxiety, and, interestingly, chronic optogenetic manipulation fully restored the UCMS-induced behavioral and neurobiological dysfunctions, including anxiety-like behavior, lower c-Fos expression in the BLA, S100 overexpression in the BLA, and higher serum corticosterone concentration. Thus, our findings suggest that chronic manipulation of BLA astrocytes is a potential therapeutic intervention target for pathological anxiety.

AMPA receptor contribution to methylmercury-mediated alteration of intracellular Ca2+ concentration in human induced pluripotent stem cell motor neurons

α motor neurons (MNs) are a target of the environmental neurotoxicant methylmercury (MeHg), accumulating MeHg and subsequently degenerating. In mouse spinal cord MN cultures, MeHg increased intracellular Ca²⁺ [Ca²⁺]_i; the AMPA receptor (AMPAR) antagonist CNQX delayed the increase in [Ca²⁺]_i, implicating the role of AMPARs in this response. Here we used human induced pluripotent stem cell-derived MNs (hiPSC-MNs), to characterize the role of MN AMPARs in MeHg neurotoxicity. Acute exposure to MeHg (0.1, 0.2, 0.5, 1 and 1.5 μM), fura-2 microfluorimetry, and a standard cytotoxicity assay, were used to examine MN regulation of [Ca²⁺]_i, and cytotoxicity, respectively. Contribution of Ca²⁺-permeable and impermeable AMPARs was compared using either CNQX, or the Ca²⁺-permeable AMPAR antagonist N-acetyl spermine (NAS). MeHg-induced cytotoxicity was evaluated following a 24 h delay subsequent to 1 h exposure of hiPSC-MNs. MeHg caused a characteristic biphasic increase in [Ca²⁺]_i, the onset of which was concentration-dependent; higher MeHg concentrations hastened onset of both phases. CNQX significantly delayed MeHg's effect on onset time of both phases. In contrast, NAS significantly delayed only the 2nd phase increase in fura-2 fluorescence. Exposure to MeHg for 1 h followed by a 24 h recovery period caused a concentration-dependent incidence of cell death. These results demonstrate for the first time that hiPSC-derived MNs are highly sensitive to effects of MeHg on [Ca²⁺]_i, and cytotoxicity, and that both Ca²⁺-permeable and impermeable AMPARs contribute the elevations in [Ca²⁺]_i.

Extracellular Vesicles as Nanotherapeutics for Parkinson's Disease

Extracellular vesicles (EVs) are naturally occurring membranous structures secreted by normal and diseased cells, and carrying a wide range of bioactive molecules. In the central nervous system (CNS), EVs are important in both homeostasis and pathology. Through receptor-ligand interactions, direct fusion, or endocytosis, EVs interact with their target cells. Accumulating evidence indicates that EVs play crucial roles in the pathogenesis of many neurodegenerative disorders (NDs), including Parkinson's disease (PD). PD is the second most common ND, characterized by the progressive loss of dopaminergic (DAergic) neurons within the Substantia Nigra pars compacta (SNpc). In PD, EVs are secreted by both neurons and glial cells, with either beneficial or detrimental effects, via a complex program of cell-to-cell communication. The functions of EVs in PD range from their etiopathogenetic relevance to their use as diagnostic tools and innovative carriers of therapeutics. Because they can cross the blood-brain barrier, EVs can be engineered to deliver bioactive molecules (e.g., small interfering RNAs, catalase) within the CNS. This review summarizes the latest findings regarding the role played by EVs in PD etiology, diagnosis, prognosis, and therapy, with a particular focus on their use as novel PD nanotherapeutics.

Nrf2/Wnt resilience orchestrates rejuvenation of glia-neuron dialogue in Parkinson's disease

Oxidative stress and inflammation have long been recognized to contribute to Parkinson's disease (PD), a common movement disorder characterized by the selective loss of midbrain dopaminergic neurons (mDAn) of the substantia nigra pars compacta (SNpc). The causes and mechanisms still remain elusive, but a complex interplay between several genes and a number of interconnected environmental factors, are chiefly involved in mDAn demise, as they intersect the key cellular functions affected in PD, such as the inflammatory response, mitochondrial, lysosomal, proteosomal and autophagic functions. Nuclear factor erythroid 2 -like 2 (NFE2L2/Nrf2), the master regulator of cellular defense against oxidative stress and inflammation, and Wingless (Wnt)/β-catenin signaling cascade, a vital pathway for mDAn neurogenesis and neuroprotection, emerge as critical intertwinned actors in mDAn physiopathology, as a decline of an Nrf2/Wnt/β-catenin prosurvival axis with age underlying PD mutations and a variety of noxious environmental exposures drive PD neurodegeneration. Unexpectedly, astrocytes, the so-called "star-shaped" cells, harbouring an arsenal of "beneficial" and "harmful" molecules represent the turning point in the physiopathological and therapeutical scenario of PD. Fascinatingly, "astrocyte's fil rouge" brings back to Nrf2/Wnt resilience, as boosting the Nrf2/Wnt resilience program rejuvenates astrocytes, in turn (i) mitigating nigrostriatal degeneration of aged mice, (ii) reactivating neural stem progenitor cell proliferation and neuron differentiation in the brain and (iii) promoting a beneficial immunomodulation via bidirectional communication with mDAns. Then, through resilience of Nrf2/Wnt/β-catenin anti-ageing, prosurvival and proregenerative molecular programs, it seems possible to boost the inherent endogenous self-repair mechanisms. Here, the cellular and molecular aspects as well as the therapeutical options for rejuvenating glia-neuron dialogue will be discussed together with major glial-derived mechanisms and therapies that will be fundamental to the identification of novel diagnostic tools and treatments for neurodegenerative diseases (NDs), to fight ageing and nigrostriatal DAergic degeneration and promote functional recovery.

Prediction of genomic breeding values based on pre-selected SNPs using ssGBLUP, WssGBLUP and BayesB for Edwardsiellosis resistance in Japanese flounder

Background

Edwardsiella tarda causes acute symptoms with ascites in Japanese flounder (Paralichthys olivaceus) and is a major problem for China’s aquaculture sector. Genomic selection (GS) has been widely adopted in breeding industries because it shortens generation intervals and results in the selection of individuals that have great breeding potential with high accuracy. Based on an artificial challenge test and re-sequenced data of 1099 flounders, the aims of this study were to estimate the genetic parameters of resistance to E. tarda in Japanese flounder and to evaluate the accuracy of single-step GBLUP (ssGBLUP), weighted ssGBLUP (WssGBLUP), and BayesB for improving resistance to E. tarda by using three subsets of pre-selected single nucleotide polymorphisms (SNPs). In addition, SNPs that are associated with this trait were identified using a single-SNP genome-wide association study (GWAS) and WssGBLUP.

Results

We estimated a heritability of 0.13 ± 0.02 for resistance to E. tarda in Japanese flounder. One million SNPs at fixed intervals were selected from 4,978,724 SNPs that passed quality controls. GWAS identified significant SNPs on chromosomes 14 and 24. WssGBLUP revealed that the putative quantitative trait loci on chromosomes 1 and 14 contained SNPs that explained more than 1% of the genetic variance. Three 50 k-SNP subsets were pre-selected based on different criteria. Compared with pedigree-based prediction (ABLUP), the three genomic methods evaluated resulted in at least 7.7% greater accuracy of predictions. The accuracy of these genomic prediction methods was almost unchanged when pre-selected trait-related SNPs were used for prediction.

Conclusions

Resistance to E. tarda in Japanese flounder has a low heritability. GWAS and WssGBLUP revealed that the genetic architecture of this trait is polygenic. Genomic prediction of breeding values performed better than ABLUP. It is feasible to implement genomic selection to increase resistance to E. tarda in Japanese flounder with 50 k SNPs. Based on the criteria used here, pre-selection of SNPs was not beneficial and other criteria for pre-selection should be considered.

Laminin 511 Precoating Promotes the Functional Recovery of Transplanted Corneal Endothelial Cells

Corneal endothelial dysfunction is a major cause of corneal blindness and is mainly treated by corneal transplantation. However, the global shortage of donor cornea hampers its application. Intracameral injection of cultured primary corneal endothelial cells (CECs) was recently confirmed in clinical trials. However, abnormal adhesion of the grafted CECs affects the application of this strategy. In this study, we explored if laminin 511 (LN511) improves the therapeutic function of the intracameral CEC injection for corneal endothelial dysfunction. To mimic the late stage of corneal endothelial diseases, intense scraping was developed to remove CECs and extracellular matrix of the posterior Descemet's membrane (DM) without DM removal in rabbits. Then, Dulbecco's phosphate-buffered saline (DPBS) and LN511 were intracamerally injected as the control and intervention groups, respectively. We found that the injected LN511 could settle and form a coating on the posterior surface of DM. After CEC transplantation, corneal clarity of rabbits in the LN511 group was rapidly recovered within 7 days, whereas the corneal recovery took 14 days in the DPBS group. Corneal thickness of LN511 group decreased to 413.3 ± 20.8 μm 7 days after operation, which was significantly lower than 1086.3 ± 78.6 μm of DPBS group (p < 0.01). Moreover, for the grafted CECs, LN511 promoted the rapid adhesion, tight junction formation, and expression of Na⁺/K⁺-ATPase and ZO-1. In vitro analysis revealed that the functions of LN511 on the cultured human CECs mechanistically depended on the cell density and the nuclear-cytoplasmic translocation of the Yes-associated protein. Our study demonstrated that LN511 precoating promoted the adhesion of the transplanted CECs and enhanced the functional regeneration of the corneal endothelium. Thus, our data suggested that the strategy of LN511 precoating and CECs' intracameral injection could be a potential method for the therapy of corneal endothelial dysfunction. Impact statement Intracameral injection of cultured corneal endothelial cells (CECs) is a potential alternative therapy for corneal endothelial dysfunction and has been proven to be effective in clinical trials. However, abnormal adhesion of the grafted CECs affects its application. In this study, intense scraping was developed to remove CECs and extracellular matrix of the posterior Descemet's membrane (DM) without DM removal for the therapy of late stage of corneal endothelial diseases. Laminin 511 was intracamerally injected to form a coating, improve the posterior DM, enhance the adhesion of the grafted CECs, and promote the functional regeneration of CEC transplantation through Yes-associated protein signaling.

Correlation Between SNPs at the 3'UTR of the FGF2 Gene and Their Interaction with Environmental Factors in Han Chinese Diabetic Peripheral Neuropathy Patients

FGF2 is a neurotrophic factor that can act as a key regulatory molecule of neuroprotection, neurogenesis, and angiogenesis in various injuries. To explore the genetic background of the FGF2 gene on DPN development, this study analyzed the correlation between SNPs in the 3'UTR of the FGF2 gene and their interaction with environmental factors in DPN patients of Han Chinese nationality. Sanger sequencing was used to analyze the FGF2 genotypes at the rs1048201, rs3804158, rs41348645, rs6854081, rs3747676, rs7683093, rs1476215, and rs1476217 loci in 150 DPN patients, 150 NDPN patients, and 150 healthy control patients. Plasma FGF2 levels were measured in all subjects by using ELISAs. Subjects carrying the T allele at the rs1048201 locus in the FGF2 gene had a significantly lower risk of developing DPN compared with subjects carrying the C allele (OR = 0.43, 95% CI = 0.33-0.56, p < 0.01). Subjects with the G genotype at the rs6854081 locus had an exceptionally higher risk of developing DPN than subjects with the T allele (OR = 1.66, 95% CI = 1.39-1.89, p < 0.01). Individuals harboring the G allele at the rs7683093 locus had a markedly higher risk of DPN than patients with the C allele (OR = 1.63, 95% CI = 1.36-1.87, p < 0.01). Finally, individuals having the A genotype at the rs1476215 locus had a significantly higher risk of DPN than individuals carrying the T allele (OR = 1.82, 95% CI = 1.53-2.02, p < 0.01). There was an interaction between age and alcohol consumption and the SNP rs7683093. SNPs at rs1048201, rs6854081, rs7683093, and rs1476215 in the FGF2 3'UTR were strongly associated with plasma levels of FGF2 (p < 0.05). SNPs at the rs1048201, rs6854081, rs7683093, and rs1476215 loci in the FGF2 gene were significantly associated with the risk of DPN. A possible mechanism is that these SNPs affect the expression level of FGF2 by interrupting the binding of microRNAs to target sites in the 3'UTR.

Glia-Derived Extracellular Vesicles in Parkinson's Disease

Glial cells are fundamental players in the central nervous system (CNS) development and homeostasis, both in health and disease states. In Parkinson’s disease (PD), a dysfunctional glia-neuron crosstalk represents a common final pathway contributing to the chronic and progressive death of dopaminergic (DAergic) neurons of the substantia nigra pars compacta (SNpc). Notably, glial cells communicating with each other by an array of molecules, can acquire a “beneficial” or “destructive” phenotype, thereby enhancing neuronal death/vulnerability and/or exerting critical neuroprotective and neuroreparative functions, with mechanisms that are actively investigated. An important way of delivering messenger molecules within this glia-neuron cross-talk consists in the secretion of extracellular vesicles (EVs). EVs are nano-sized membranous particles able to convey a wide range of molecular cargoes in a controlled way, depending on the specific donor cell and the microenvironmental milieu. Given the dual role of glia in PD, glia-derived EVs may deliver molecules carrying various messages for the vulnerable/dysfunctional DAergic neurons. Here, we summarize the state-of-the-art of glial-neuron interactions and glia-derived EVs in PD. Also, EVs have the ability to cross the blood brain barrier (BBB), thus acting both within the CNS and outside, in the periphery. In these regards, this review discloses the emerging applications of EVs, with a special focus on glia-derived EVs as potential carriers of new biomarkers and nanotherapeutics for PD.

A review of possible therapies for Parkinson's disease

Parkinson's disease (PD) is a complex condition with a wide range of symptoms, like impaired movement, tremors, apathy and depression, and many other symptoms. The disease results from degeneration of dopaminergic neural cells. No cure at present but symptomatic some palliative treatments are available to slow down the disease progression. According to the Parkinson's Foundation every year in U.S., approximately 60,000 Americans diagnosed with PD. Nearly one million will be living with PD in the U.S. by 2020, which is more than the combined number of people diagnosed with multiple sclerosis, muscular dystrophy and Amyotrophic Lateral Sclerosis (ALS). There is no diagnostic test for PD, yet, but this article will review all kinds symptomatic and disease-modifying therapy.

Possible therapies of Parkinson's disease: A review

Parkinson's disease (PD) is a complex condition with a wide range of symptoms, like impaired movement, tremors, apathy and depression, and many other symptoms. The disease results from degeneration of dopaminergic neural cells. No cure at present but symptomatic some palliative treatments are available to slow down the disease progression. According to the Parkinson's Foundation every year in U.S., approximately 60,000 Americans diagnosed with PD. Nearly one million will be living with PD in the U.S. by 2020, which is more than the combined number of people diagnosed with multiple sclerosis, muscular dystrophy and Amyotrophic Lateral Sclerosis (ALS). There is no diagnostic test for PD, yet, but this article will review all kinds symptomatic and disease-modifying therapy.

Boosting Antioxidant Self-defenses by Grafting Astrocytes Rejuvenates the Aged Microenvironment and Mitigates Nigrostriatal Toxicity in Parkinsonian Brain via an Nrf2-Driven Wnt/β-Catenin Prosurvival Axis

Astrocyte (As) bidirectional dialog with neurons plays a fundamental role in major homeostatic brain functions, particularly providing metabolic support and antioxidant self-defense against reactive oxygen (ROS) and nitrogen species (RNS) via the activation of NF-E2-related factor 2 (Nrf2), a master regulator of oxidative stress. Disruption of As-neuron crosstalk is chiefly involved in neuronal degeneration observed in Parkinson's disease (PD), the most common movement disorder characterized by the selective degeneration of dopaminergic (DAergic) cell bodies of the substantia nigra (SN) pars compacta (SNpc). Ventral midbrain (VM)-As are recognized to exert an important role in DAergic neuroprotection via the expression of a variety of factors, including wingless-related MMTV integration site 1 (Wnt1), a principal player in DAergic neurogenesis. However, whether As, by themselves, might fulfill the role of chief players in DAergic neurorestoration of aged PD mice is presently unresolved. Here, we used primary postnatal mouse VM-As as a graft source for unilateral transplantation above the SN of aged 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mice after the onset of motor symptoms. Spatio-temporal analyses documented that the engrafted cells promoted: (i) a time-dependent nigrostriatal rescue along with increased high-affinity synaptosomal DA uptake and counteraction of motor deficit, as compared to mock-grafted counterparts; and (ii) a restoration of the impaired microenvironment via upregulation of As antioxidant self-defense through the activation of Nrf2/Wnt/β-catenin signaling, suggesting that grafting As has the potential to switch the SN neurorescue-unfriendly environment to a beneficial antioxidant/anti-inflammatory prosurvival milieu. These findings highlight As-derived factors/mechanisms as the crucial key for successful therapeutic outcomes in PD.

Parkinson's disease, aging and adult neurogenesis: Wnt/β-catenin signalling as the key to unlock the mystery of endogenous brain repair

A common hallmark of age-dependent neurodegenerative diseases is an impairment of adult neurogenesis. Wingless-type mouse mammary tumor virus integration site (Wnt)/β-catenin (WβC) signalling is a vital pathway for dopaminergic (DAergic) neurogenesis and an essential signalling system during embryonic development and aging, the most critical risk factor for Parkinson's disease (PD). To date, there is no known cause or cure for PD. Here we focus on the potential to reawaken the impaired neurogenic niches to rejuvenate and repair the aged PD brain. Specifically, we highlight WβC-signalling in the plasticity of the subventricular zone (SVZ), the largest germinal region in the mature brain innervated by nigrostriatal DAergic terminals, and the mesencephalic aqueduct-periventricular region (Aq-PVR) Wnt-sensitive niche, which is in proximity to the SNpc and harbors neural stem progenitor cells (NSCs) with DAergic potential. The hallmark of the WβC pathway is the cytosolic accumulation of β-catenin, which enters the nucleus and associates with T cell factor/lymphoid enhancer binding factor (TCF/LEF) transcription factors, leading to the transcription of Wnt target genes. Here, we underscore the dynamic interplay between DAergic innervation and astroglial-derived factors regulating WβC-dependent transcription of key genes orchestrating NSC proliferation, survival, migration and differentiation. Aging, inflammation and oxidative stress synergize with neurotoxin exposure in "turning off" the WβC neurogenic switch via down-regulation of the nuclear factor erythroid-2-related factor 2/Wnt-regulated signalosome, a key player in the maintenance of antioxidant self-defense mechanisms and NSC homeostasis. Harnessing WβC-signalling in the aged PD brain can thus restore neurogenesis, rejuvenate the microenvironment, and promote neurorescue and regeneration.

TGF-β Determines the Pro-migratory Potential of bFGF Signaling in Medulloblastoma

The microenvironment shapes cell behavior and determines metastatic outcomes of tumors. We addressed how microenvironmental cues control tumor cell invasion in pediatric medulloblastoma (MB). We show that bFGF promotes MB tumor cell invasion through FGF receptor (FGFR) in vitro and that blockade of FGFR represses brain tissue infiltration in vivo. TGF-β regulates pro-migratory bFGF function in a context-dependent manner. Under low bFGF, the non-canonical TGF-β pathway causes ROCK activation and cortical translocation of ERK1/2, which antagonizes FGFR signaling by inactivating FGFR substrate 2 (FRS2), and promotes a contractile, non-motile phenotype. Under high bFGF, negative-feedback regulation of FRS2 by bFGF-induced ERK1/2 causes repression of the FGFR pathway. Under these conditions, TGF-β counters inactivation of FRS2 and restores pro-migratory signaling. These findings pinpoint coincidence detection of bFGF and TGF-β signaling by FRS2 as a mechanism that controls tumor cell invasion. Thus, targeting FRS2 represents an emerging strategy to abrogate aberrant FGFR signaling.

The Effect of Sertoli Cells on Xenotransplantation and Allotransplantation of Ventral Mesencephalic Tissue in a Rat Model of Parkinson's Disease

Intra-striatal transplantation of fetal ventral mesencephalic (VM) tissue has a therapeutic effect on patients with Parkinson’s disease (PD). Sertoli cells (SCs) possess immune-modulatory properties that benefit transplantation. We hypothesized that co-graft of SCs with VM tissue can attenuate rejection. Hemi-parkinsonian rats were generated by injecting 6-hydroxydopamine into the right medial forebrain bundle of Sprague Dawley (SD) rats. The rats were then intrastriatally transplanted with VM tissue from rats or pigs (rVM or pVM), with/without a co-graft of SCs (rVM+SCs or pVM+SCs). Recovery of dopaminergic function and survival of the grafts were evaluated using the apomorphine-induced rotation test and small animal-positron emission tomography (PET) coupled with [¹⁸F] DOPA or [¹⁸F] FE-PE2I, respectively. Immunohistochemistry (IHC) examination was used to determine the survival of the grafted dopaminergic neurons in the striatum and to investigate immune-modulatory effects of SCs. The results showed that the rVM+SCs and pVM+SCs groups had significantly improved drug-induced rotational behavior compared with the VM alone groups. PET revealed a significant increase in specific uptake ratios (SURs) of [¹⁸F] DOPA and [¹⁸F] FE-PE2I in the grafted striatum of the rVM+SCs and pVM+SCs groups as compared to that of the rVM and pVM groups. SC and VM tissue co-graft led to better dopaminergic (DA) cell survival. The co-grafted groups exhibited lower populations of T-cells and activated microglia compared to the groups without SCs. Our results suggest that co-graft of SCs benefit both xeno- and allo-transplantation of VM tissue in a PD rat model. Use of SCs enhanced the survival of the grafted dopaminergic neurons and improved functional recovery. The enhancement may in part be attributable to the immune-modulatory properties of SCs. In addition, [¹⁸F]DOPA and [¹⁸F]FE-PE2I coupled with PET may provide a feasible method for in vivo evaluation of the functional integrity of the grafted DA cell in parkinsonian rats.

Optogenetic manipulation of astrocytes from synapses to neuronal networks: A potential therapeutic strategy for neurodegenerative diseases

Astrocytes are the most widespread and heterogeneous glial cells in the central nervous system and key regulators for brain development. They are capable of receiving neurotransmitters produced by synaptic activities and regulating synaptic functions by releasing gliotransmitters as part of the tripartite synapse. In addition to communicating with neurons at synaptic levels, astrocytes can integrate into inhibitory neural networks to interact with neurons in neuronal circuits. Astrocytes are closely related to the pathogenesis and pathological processes of neurodegenerative diseases (NDs). Recently, optogenetics has now been applied to reveal the function of astrocytes in physiology and pathology. Herein, we discuss the possibility whether optogenetics could be used to control the release of gliotransmitters and regulate astrocytic membrane channels. Thus, the capability of modulating the bidirectional interactions between astrocytes and neurons in both synaptic and neuronal networks via optogenetics is evaluated. Furthermore, we discuss that manipulating astrocytes via optogenetics might be an effective way to investigate the potential therapeutic strategy for NDs.

Neural Stem Cell Grafts Promote Astroglia-Driven Neurorestoration in the Aged Parkinsonian Brain via Wnt/β-Catenin Signaling

neuronal phenotype. Wnt/β-catenin signaling antagonism abolished mDA neurorestoration and immune modulatory effects of NSC grafts. Our work implicates an unprecedented therapeutic potential for somatic NSC grafts in the restoration of mDA neuronal function in the aged Parkinsonian brain. Stem Cells 2018;36:1179-1197.

Bioluminescence-driven optogenetic activation of transplanted neural precursor cells improves motor deficits in a Parkinson's disease mouse model

The need to develop efficient therapies for neurodegenerative diseases is urgent, especially given the increasing percentages of the population living longer, with increasing chances of being afflicted with conditions like Parkinson's disease (PD). A promising curative approach toward PD and other neurodegenerative diseases is the transplantation of stem cells to halt and potentially reverse neuronal degeneration. However, stem cell therapy does not consistently lead to improvement for patients. Using remote stimulation to optogenetically activate transplanted cells, we attempted to improve behavioral outcomes of stem cell transplantation. We generated a neuronal precursor cell line expressing luminopsin 3 (LMO3), a luciferase-channelrhodopsin fusion protein, which responds to the luciferase substrate coelenterazine (CTZ) with emission of blue light that in turn activates the opsin. Neuronal precursor cells were injected bilaterally into the striatum of homozygous aphakia mice, which carry a spontaneous mutation leading to lack of dopaminergic neurons and symptoms of PD. Following transplantation, the cells were stimulated over a period of 10 days by intraventricular injections of CTZ. Mice receiving CTZ demonstrated significantly improved motor skills in a rotarod test compared to mice receiving vehicle. Thus, bioluminescent optogenetic stimulation of transplanted neuronal precursor cells shows promising effects in improving locomotor behavior in the aphakia PD mouse model and encourages further studies to elucidate the mechanisms and long-term outcomes of these beneficial effects.

Astrocytes Attenuate Mitochondrial Dysfunctions in Human Dopaminergic Neurons Derived from iPSC

Astrocytes, the most populous glial cell type in the brain, are critical for regulating the brain microenvironment. In various neurodegenerative diseases, astrocytes determine the progression and outcome of the neuropathological process. We have recently revealed the direct involvement of mitochondrial function in human pluripotent stem cell (hiPSC)-derived dopaminergic (DA) neuronal differentiation. Using the astroglial-neuronal co-culture system, we show here that astrocytes effectively rescue defects in neurogenesis of DA neurons with mitochondrial respiratory chain disruption. Co-culture of astrocytes with defective DA neurons completely restored mitochondrial functions and dynamics insulted by mitochondrial toxins. These results suggest the significance of astroglia in maintaining mitochondrial development and bioenergetics during differentiation of hiPSC-derived DA neurons. Our study also provides an active astroglial-neuronal interaction model for future investigation of mitochondrial involvement in neurogenesis and neurodegenerative diseases.

•

Role of astrocyte on the development of hiPSC-derived dopaminergic neuron

•

Astrocyte protects dopaminergic neurogenesis by powering up mitochondrial respiration

•

Astrocyte restores mitochondrial function and dynamics in dopaminergic neuron

•

Evidence of astroglial and neuronal interaction during dopaminergic neurogenesis

Basic Fibroblast Growth Factor Protects Astrocytes Against Ischemia/Reperfusion Injury by Upregulating the Caveolin-1/VEGF Signaling Pathway

A previous in vivo study demonstrated that intracerebroventricular injection of basic fibroblast growth factor (bFGF) in middle cerebral artery occlusion rats increased the expression of caveolin-1 (cav-1) and vascular endothelial growth factor (VEGF) in cerebral ischemia penumbra. Because astrocytes are the largest population in the brain, the aim of this in vitro study was to investigate the influence of bFGF on cav-1 and VEGF expression in rat astrocytes following oxygen glucose deprivation/reoxygenation (OGD/R). For this, an ischemic model in vitro of oxygen glucose deprivation lasting for 6 h, followed by 24 h of reoxygenation was used. Primary astrocytes from newborn rats were pre-treated with siRNA targeting bFGF before OGD/R. Cell viability was measured by a CCK-8 assay. The protein and mRNA expressions of bFGF, cav-1, and VEGF were evaluated by western blotting, immunofluorescence staining, and reverse transcription-quantitative polymerase chain reaction. The results showed that OGD/R reduced cell viability, which was decreased further following bFGF knockdown; however, restoring bFGF improved cell survival. A cav-1 inhibitor abrogated the effect of bFGF on cell viability. The expression levels of bFGF mRNA, bFGF protein, cav-1 mRNA, cav-1 protein, and VEGF protein were higher in OGD/R astrocytes. bFGF knockdown markedly decreased the expression levels of cav-1 mRNA, cav-1 protein, and VEGF protein, which were effectively reversed by exogenous bFGF treatment. Moreover, exogenous bFGF treatment significantly increased the expression levels of cav-1 mRNA, cav-1 protein, and VEGF protein in OGD/R astrocytes; however, a cav-1 inhibitor abolished the effect of bFGF on VEGF protein expression. These results suggested that bFGF may protect astrocytes against ischemia/reperfusion injury by upregulating caveolin-1/VEGF signaling pathway.

Functional dissection of astrocyte-secreted proteins: Implications in brain health and diseases

Astrocytes, which are homeostatic cells of the central nervous system (CNS), display remarkable heterogeneity in their morphology and function. Besides their physical and metabolic support to neurons, astrocytes modulate the blood-brain barrier, regulate CNS synaptogenesis, guide axon pathfinding, maintain brain homeostasis, affect neuronal development and plasticity, and contribute to diverse neuropathologies via secreted proteins. The identification of astrocytic proteome and secretome profiles has provided new insights into the maintenance of neuronal health and survival, the pathogenesis of brain injury, and neurodegeneration. Recent advances in proteomics research have provided an excellent catalog of astrocyte-secreted proteins. This review categorizes astrocyte-secreted proteins and discusses evidence that astrocytes play a crucial role in neuronal activity and brain function. An in-depth understanding of astrocyte-secreted proteins and their pathways is pivotal for the development of novel strategies for restoring brain homeostasis, limiting brain injury/inflammation, counteracting neurodegeneration, and obtaining functional recovery.

Current understanding of the molecular mechanisms in Parkinson's disease: Targets for potential treatments

Gradual degeneration and loss of dopaminergic neurons in the substantia nigra, pars compacta and subsequent reduction of dopamine levels in striatum are associated with motor deficits that characterize Parkinson’s disease (PD). In addition, half of the PD patients also exhibit frontostriatal-mediated executive dysfunction, including deficits in attention, short-term working memory, speed of mental processing, and impulsivity. The most commonly used treatments for PD are only partially or transiently effective and are available or applicable to a minority of patients. Because, these therapies neither restore the lost or degenerated dopaminergic neurons, nor prevent or delay the disease progression, the need for more effective therapeutics is critical. In this review, we provide a comprehensive overview of the current understanding of the molecular signaling pathways involved in PD, particularly within the context of how genetic and environmental factors contribute to the initiation and progression of this disease. The involvement of molecular chaperones, autophagy-lysosomal pathways, and proteasome systems in PD are also highlighted. In addition, emerging therapies, including pharmacological manipulations, surgical procedures, stem cell transplantation, gene therapy, as well as complementary, supportive and rehabilitation therapies to prevent or delay the progression of this complex disease are reviewed.

Effects of ginsenoside‑Rg1 on the proliferation and glial‑like directed differentiation of embryonic rat cortical neural stem cells in vitro

Ginsenoside-Rg1, the main active component of Panax notoginseng, exhibits a number of pharmacological functions, including promoting protein synthesis in the brain, increasing the number of synapses, improving memory and promoting recovery of brain function following injury. The effect of ginsenoside-Rg1 on proliferation and glial-like-directed differentiation in the cortical neural stem cells (NSCs) of embryonic rat brain was investigated. The present study used MTS assays to identify the optimum dose and window time of ginsenoside-Rg1 administration to stimulate the proliferation of cortical NSCs in the rat embryonic tissue. The oxygen glucose deprivation (OGD) set-up was used as a cell injury model. Immunofluorescent staining was used for identification of NSCs and subsequent observation of their proliferation and glial-like directed differentiation. Nestin expression was the marker for the presence of NSCs among the cortical cells of embryonic rat brain. The optimum dose of ginsenoside-Rg1 for proliferation of NSCs was 0.32 µg/ml. The optimum window time of 0.32 µg/ml ginsenoside-Rg1 administration on proliferation of NSCs was 6 h. Ginsenoside-Rg1 at 0.32 µg/ml concentration promoted incorporation of bromo-2-deoxyuridine, and expression of nestin and vimentin in primary and passaged NSCs, and NSCs following OGD. Ginsenoside-Rg1 had a role in promoting proliferation and glial-like-directed differentiation of cortical NSCs. The plausible explanation for these responses is that ginsenoside-Rg1 acts similarly to the growth factors to promote the proliferation and differentiation of NSCs.

Chiro-Optical Modulation for NURR1 Production from Stem Cells

Nuclear receptor related 1 (NURR1) is an essential protein for maintenance of dopaminergic neurons in adult midbrain of which deficiency leads to Parkinson's disease. To enhance the NURR1 production of neural cells, various approaches are under investigation. Here we report that NURR1 is highly expressed in stem cells by exposure to an L-polarized blue light emitting diode (LED). Compared to stem cells cultured in the absence of a LED, under polarized green and red LEDs, the stem cells exposed to a polarized blue LED significantly enhanced neuronal biomarkers such as neurofilament M (NFM) and neuron specific enolase (NSE) at both mRNA and protein levels. In particular, NURR1 was selectively enhanced by the stem cells exposed to the L-polarized blue LED. Stem cells exposed to the L-polarized blue LED increased mitochondrial ATP and intracellular calcium ions, which support neuronal differentiation of the stem cells. This study suggests that chiro-optical treatments by using polarized light with a specific wavelength can be used for engineering of stem cells with enhanced specific biochemicals, which may open a new method for a specific disease.

Derivation of Functional Human Astrocytes from Cerebral Organoids

Astrocytes play a critical role in the development and homeostasis of the central nervous system (CNS). Astrocyte dysfunction results in several neurological and degenerative diseases. However, a major challenge to our understanding of astrocyte physiology and pathology is the restriction of studies to animal models, human post-mortem brain tissues, or samples obtained from invasive surgical procedures. Here, we report a protocol to generate human functional astrocytes from cerebral organoids derived from human pluripotent stem cells. The cellular isolation of cerebral organoids yielded cells that were morphologically and functionally like astrocytes. Immunolabelling and proteomic assays revealed that human organoid-derived astrocytes express the main astrocytic molecular markers, including glutamate transporters, specific enzymes and cytoskeletal proteins. We found that organoid-derived astrocytes strongly supported neuronal survival and neurite outgrowth and responded to ATP through transient calcium wave elevations, which are hallmarks of astrocyte physiology. Additionally, these astrocytes presented similar functional pathways to those isolated from adult human cortex by surgical procedures. This is the first study to provide proteomic and functional analyses of astrocytes isolated from human cerebral organoids. The isolation of these astrocytes holds great potential for the investigation of developmental and evolutionary features of the human brain and provides a useful approach to drug screening and neurodegenerative disease modelling.

Serotonin 1A Receptors on Astrocytes as a Potential Target for the Treatment of Parkinson's Disease

Astrocytes are the most abundant neuron-supporting glial cells in the central nervous system. The neuroprotective role of astrocytes has been demonstrated in various neurological disorders such as amyotrophic lateral sclerosis, spinal cord injury, stroke and Parkinson’s disease (PD). Astrocyte dysfunction or loss-of-astrocytes increases the susceptibility of neurons to cell death, while astrocyte transplantation in animal studies has therapeutic advantage. We reported recently that stimulation of serotonin 1A (5-HT_1A) receptors on astrocytes promoted astrocyte proliferation and upregulated antioxidative molecules to act as a neuroprotectant in parkinsonian mice. PD is a progressive neurodegenerative disease with motor symptoms such as tremor, bradykinesia, rigidity and postural instability, that are based on selective loss of nigrostriatal dopaminergic neurons, and with non-motor symptoms such as orthostatic hypotension and constipation based on peripheral neurodegeneration. Although dopaminergic therapy for managing the motor disability associated with PD is being assessed at present, the main challenge remains the development of neuroprotective or disease-modifying treatments. Therefore, it is desirable to find treatments that can reduce the progression of dopaminergic cell death. In this article, we summarize first the neuroprotective properties of astrocytes targeting certain molecules related to PD. Next, we review neuroprotective effects induced by stimulation of 5-HT_1A receptors on astrocytes. The review discusses new promising therapeutic strategies based on neuroprotection against oxidative stress and prevention of dopaminergic neurodegeneration.

Progesterone analogue protects stressed photoreceptors via bFGF-mediated calcium influx

Retinitis pigmentosa (RP) is a degenerative retinal disease leading to photoreceptor cell loss. In 2011, our group identified the synthetic progesterone 'Norgestrel' as a potential treatment for RP. Subsequent research showed Norgestrel to work through progesterone receptor membrane component 1 (PGRMC1) activation and upregulation of neuroprotective basic fibroblast growth factor (bFGF). Using trophic factor deprivation of 661W photoreceptor-like cells, we aimed to further elucidate the mechanism leading to Norgestrel-induced neuroprotection. In the present manuscript, we show by flow cytometry and live-cell immunofluorescence that Norgestrel induces an increase in cytosolic calcium in both healthy and stressed 661Ws over 24 h. Specific PGRMC1 inhibition by AG205 (1 μm) showed this rise to be PGRMC1-dependent, primarily utilizing calcium from extracellular sources, for blockade of L-type calcium channels by verapamil (50 μm) prevented a Norgestrel-induced calcium influx in stressed cells. Calcium influx was also shown to be bFGF-dependent, for siRNA knock down of bFGF prevented Norgestrel-PGRMC1 induced changes in cytosolic calcium. Notably, we demonstrate PGRMC1-activation is necessary for Norgestrel-induced bFGF upregulation. We propose that Norgestrel protects through the following pathway: binding to and activating PGRMC1 expressed on the surface of photoreceptor cells, PGRMC1 activation drives bFGF upregulation and subsequent calcium influx. Importantly, raised intracellular calcium is critical to Norgestrel's protective efficacy, for extracellular calcium chelation by EGTA abrogates the protective effects of Norgestrel on stressed 661W cells in vitro.

Transplantation of RADA16-BDNF peptide scaffold with human umbilical cord mesenchymal stem cells forced with CXCR4 and activated astrocytes for repair of traumatic brain injury

Due to the poor self-regeneration of brain tissue, stem cell transplantation therapy is purported to enable the replacement of lost neurons after traumatic brain injury (TBI). The main challenge of brain regeneration is whether the transplanted cells can survive and carry out neuronal functions in the lesion area. The brain is a complex neuronal network consisting of various types of cells that significantly influence on each other, and the survival of the implanted stem cells in brain is critically influenced by the surrounding cells. Although stem cell-based therapy is developing rapidly, most previous studies just focus on apply single type of stem cells as cell source. Here, we found that co-culturing human umbilical cord mesenchymal stem cells (hUC-MSCs) directly with the activated astrocytes benefited to the proliferation and neuron differentiation of hUC-MSCs in vitro. In this study, hUC-MSCs and the activated astrocytes were seeded in RADA16-BDNF peptide scaffold (R-B-SPH scaffold), a specifical self-assembling peptide hydrogel, in which the environment promoted the differentiation of typical neuron-like cells with neurites extending in three-dimensional directions. Moreover, the results showed co-culture of hUC-MSCs and activated astrocytes promoted more BDNF secretion which may benefit to both neural differentiation of ectogenic hUC-MSCs and endogenic neurogenesis. In order to promote migration of the transplanted hUC-MSCs to the host brain, the hUC-MSCs were forced with CXC chemokine receptor 4 (CXCR4). We found that the moderate-sized lesion cavity, but not the large cavity caused by TBI was repaired via the transplantation of hUC-MSCs^CXCR4 and activated astrocytes embedded in R-B-SPH scaffolds. The functional neural repair for TBI demonstrated in this study is mainly due to the transplantation system of double cells, hUC-MSCs and activated astrocytes. We believe that this novel cell transplantation system offers a promising treatment option for cell replacement therapy for TBI.

STATEMENT OF SIGNIFICANCE

In this reach, we specifically linked RGIDKRHWNSQ, a functional peptide derived from BDNF, to the C-terminal of RADARADARADARADA (RADA16) to structure a functional self-assembling peptide hydrogel scaffold, RADA16-BDNF (R-B-SPH scaffold) for the better transplantation of the double cell unit. Also, the novel scaffold was used as cell-carrier for transplantation double cell unit (hUC-MSCs/astrocyte) for treating traumatic brain injury. The results of this study showing that R-B-SPH scaffold was pliancy and flexibility to fit the brain lesion cavity and promotes the outgrowth of axons and dendrites of the neurons derived from hUC-MSCs in vitro and in vivo, indicating the 3D R-B-SPH scaffold provided a suitable microenvironment for hUC-MSC survival, proliferation and differentiation. Also, our results showing the double-cells transplantation system (hUC-MSCs/astrocyte) may be a novel cell-based therapeutic strategy for neuroregeneration after TBI with potential value for clinical application.

Therapeutic effects of intranigral transplantation of mesenchymal stem cells in rat models of Parkinson's disease

Stem cell transplantation is a promising tool for the treatment of neurodegenerative disorders, including Parkinson's disease (PD); however, the therapeutic routes and mechanisms of mechanical approaches to stem cell transplantation must be explored. This study tests the therapeutic effect of transplantation of rat bone marrow mesenchymal stem cells (MSCs) into the substantia nigra (SN) of the PD rat. 5-Bromo-2-deoxyuridine-labeled rat MSCs were transplanted into the SN of the 6-hydroxydopamine-injected side of PD rat brains. The behavioral changes in PD rats were examined before and 4 and 8 weeks after MSC transplantation. The expression of tyrosine hydroxylase (TH) in the SN and the striatum and the survival and differentiation of MSCs were assessed by immunohistochemical and double immunofluorescence techniques. Abnormal behavior of PD rats was significantly improved by the administration of bone marrow MSCs, and the number of TH-positive cells in the SN and the optical density of TH-positive fibers in the striatum were markedly increased. Transplanted MSCs can survive and migrate in the brain and differentiate into nestin-, neuron-specific enolase-, and GFAP-positive cells. Our findings suggest that transplantation of rat bone marrow MSCs into the SN of PD rats may provide therapeutic effects. © 2016 Wiley Periodicals, Inc.