PINK1 expression increases during brain development and stem cell differentiation, and affects the development of GFAP-positive astrocytes

In and out: Benchmarking in vitro, in vivo, ex vivo, and xenografting approaches for an integrative brain disease modeling pipeline

Human cellular models and their neuronal derivatives have afforded unprecedented advances in elucidating pathogenic mechanisms of neuropsychiatric diseases. Notwithstanding their indispensable contribution, animal models remain the benchmark in neurobiological research. In an attempt to harness the best of both worlds, researchers have increasingly relied on human/animal chimeras by xenografting human cells into the animal brain. Despite the unparalleled potential of xenografting approaches in the study of the human brain, literature resources that systematically examine their significance and advantages are surprisingly lacking. We fill this gap by providing a comprehensive account of brain diseases that were thus far subjected to all three modeling approaches (transgenic rodents, in vitro human lineages, human-animal xenografting) and provide a critical appraisal of the impact of xenografting approaches for advancing our understanding of those diseases and brain development. Next, we give our perspective on integrating xenografting modeling pipeline with recent cutting-edge technological advancements.

Therapeutic role of PTEN in tissue regeneration for management of neurological disorders: stem cell behaviors to an in-depth review

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) represents the initial tumor suppressor gene identified to possess phosphatase activity, governing various cellular processes including cell cycle regulation, migration, metabolic pathways, autophagy, oxidative stress response, and cellular senescence. Current evidence suggests that PTEN is critical for stem cell maintenance, self-renewal, migration, lineage commitment, and differentiation. Based on the latest available evidence, we provide a comprehensive overview of the mechanisms by which PTEN regulates activities of different stem cell populations and influences neurological disorders, encompassing autism, stroke, spinal cord injury, traumatic brain injury, Alzheimer's disease and Parkinson's disease. This review aims to elucidate the therapeutic impacts and mechanisms of PTEN in relation to neurogenesis or the stem cell niche across a range of neurological disorders, offering a foundation for innovative therapeutic approaches aimed at tissue repair and regeneration in neurological disorders. This review unravels novel therapeutic strategies for tissue restoration and regeneration in neurological disorders based on the regulatory mechanisms of PTEN on neurogenesis and the stem cell niche.

Role of Astrocytes in Parkinson's Disease Associated with Genetic Mutations and Neurotoxicants

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons and the aggregation of Lewy bodies in the basal ganglia, resulting in movement impairment referred to as parkinsonism. However, the etiology of PD is not well known, with genetic factors accounting only for 10-15% of all PD cases. The pathogenetic mechanism of PD is not completely understood, although several mechanisms, such as oxidative stress and inflammation, have been suggested. Understanding the mechanisms of PD pathogenesis is critical for developing highly efficacious therapeutics. In the PD brain, dopaminergic neurons degenerate mainly in the basal ganglia, but recently emerging evidence has shown that astrocytes also significantly contribute to dopaminergic neuronal death. In this review, we discuss the role of astrocytes in PD pathogenesis due to mutations in α-synuclein (PARK1), DJ-1 (PARK7), parkin (PARK2), leucine-rich repeat kinase 2 (LRRK2, PARK8), and PTEN-induced kinase 1 (PINK1, PARK6). We also discuss PD experimental models using neurotoxins, such as paraquat, rotenone, 6-hydroxydopamine, and MPTP/MPP+. A more precise and comprehensive understanding of astrocytes' modulatory roles in dopaminergic neurodegeneration in PD will help develop novel strategies for effective PD therapeutics.

Astrocytes in Neurodegeneration: Inspiration From Genetics

Despite the discovery of numerous molecules and pathologies, the pathophysiology of various neurodegenerative diseases remains unknown. Genetics participates in the pathogenesis of neurodegeneration. Neural dysfunction, which is thought to be a cell-autonomous mechanism, is insufficient to explain the development of neurodegenerative disease, implying that other cells surrounding or related to neurons, such as glial cells, are involved in the pathogenesis. As the primary component of glial cells, astrocytes play a variety of roles in the maintenance of physiological functions in neurons and other glial cells. The pathophysiology of neurodegeneration is also influenced by reactive astrogliosis in response to central nervous system (CNS) injuries. Furthermore, those risk-gene variants identified in neurodegenerations are involved in astrocyte activation and senescence. In this review, we summarized the relationships between gene variants and astrocytes in four neurodegenerative diseases, including Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Parkinson’s disease (PD), and provided insights into the implications of astrocytes in the neurodegenerations.

"Reframing" dopamine signaling at the intersection of glial networks in the aged Parkinsonian brain as innate Nrf2/Wnt driver: Therapeutical implications

Dopamine (DA) signaling via G protein‐coupled receptors is a multifunctional neurotransmitter and neuroendocrine–immune modulator. The DA nigrostriatal pathway, which controls the motor coordination, progressively degenerates in Parkinson's disease (PD), a most common neurodegenerative disorder (ND) characterized by a selective, age‐dependent loss of substantia nigra pars compacta (SNpc) neurons, where DA itself is a primary source of oxidative stress and mitochondrial impairment, intersecting astrocyte and microglial inflammatory networks. Importantly, glia acts as a preferential neuroendocrine–immune DA target, in turn, counter‐modulating inflammatory processes. With a major focus on DA intersection within the astrocyte–microglial inflammatory network in PD vulnerability, we herein first summarize the characteristics of DA signaling systems, the propensity of DA neurons to oxidative stress, and glial inflammatory triggers dictating the vulnerability to PD. Reciprocally, DA modulation of astrocytes and microglial reactivity, coupled to the synergic impact of gene–environment interactions, then constitute a further level of control regulating midbrain DA neuron (mDAn) survival/death. Not surprisingly, within this circuitry, DA converges to modulate nuclear factor erythroid 2‐like 2 (Nrf2), the master regulator of cellular defense against oxidative stress and inflammation, and Wingless (Wnt)/β‐catenin signaling, a key pathway for mDAn neurogenesis, neuroprotection, and immunomodulation, adding to the already complex “signaling puzzle,” a novel actor in mDAn–glial regulatory machinery. Here, we propose an autoregulatory feedback system allowing DA to act as an endogenous Nrf2/Wnt innate modulator and trace the importance of DA receptor agonists applied to the clinic as immune modifiers.

PINK1 signalling in neurodegenerative disease

PTEN-induced kinase 1 (PINK1) impacts cell health and human pathology through diverse pathways. The strict processing of full-length PINK1 on the outer mitochondrial membrane populates a cytoplasmic pool of cleaved PINK1 (cPINK1) that is constitutively degraded. However, despite rapid proteasomal clearance, cPINK1 still appears to exert quality control influence over the neuronal protein homeostasis network, including protein synthesis and degradation machineries. The cytoplasmic concentration and activity of this molecule is therefore a powerful sensor that coordinates aspects of mitochondrial and cellular health. In addition, full-length PINK1 is retained on the mitochondrial membrane following depolarisation, where it is a powerful inducer of multiple mitophagic pathways. This function is executed primarily through the phosphorylation of several ubiquitin ligases, including its most widely studied substrate Parkin. Furthermore, the phosphorylation of both pro- and anti-apoptotic proteins by mitochondrial PINK1 acts as a pro-cellular survival signal when faced with apoptotic stimuli. Through these varied roles PINK1 directly influences functions central to cell dysfunction in neurodegenerative disease.

Mitochondria in Early Forebrain Development: From Neurulation to Mid-Corticogenesis

Function of the mature central nervous system (CNS) requires a substantial proportion of the body’s energy consumption. During development, the CNS anlage must maintain its structure and perform stage-specific functions as it proceeds through discrete developmental stages. While key extrinsic signals and internal transcriptional controls over these processes are well appreciated, metabolic and mitochondrial states are also critical to appropriate forebrain development. Specifically, metabolic state, mitochondrial function, and mitochondrial dynamics/localization play critical roles in neurulation and CNS progenitor specification, progenitor proliferation and survival, neurogenesis, neural migration, and neurite outgrowth and synaptogenesis. With the goal of integrating neurodevelopmental biologists and mitochondrial specialists, this review synthesizes data from disparate models and processes to compile and highlight key roles of mitochondria in the early development of the CNS with specific focus on forebrain development and corticogenesis.

Role of Cleaved PINK1 in Neuronal Development, Synaptogenesis, and Plasticity: Implications for Parkinson's Disease

Mitochondrial dysfunction plays a significant role in the pathogenesis of Parkinson's disease (PD). Consistent with this concept, loss of function mutations in the serine/threonine kinase- PINK1 (PTEN-induced putative kinase-1) causes autosomal recessive early onset PD. While the functional role of f-PINK1 (full-length PINK1) in clearing dysfunctional mitochondria via mitophagy is extensively documented, our understanding of specific physiological roles that the non-mitochondrial pool of PINK1 imparts in neurons is more limited. PINK1 is proteolytically processed in the intermembrane space and matrix of the mitochondria into functional cleaved products (c-PINK1) that are exported to the cytosol. While it is clear that posttranslational processing of PINK1 depends on the mitochondria's oxidative state and structural integrity, the functional roles of c-PINK1 in modulating neuronal functions are poorly understood. Here, we review the diverse roles played by c-PINK1 in modulating various neuronal functions. Specifically, we describe the non-canonical functional roles of PINK1, including but not limited to: governing mitochondrial movement, neuronal development, neuronal survival, and neurogenesis. We have published that c-PINK1 stimulates neuronal plasticity and differentiation via the PINK1-PKA-BDNF signaling cascade. In addition, we provide insight into how mitochondrial membrane potential-dependent processing of PINK1 confers conditional retrograde signaling functions to PINK1. Further studies delineating the role of c-PINK1 in neurons would increase our understanding regarding the role played by PINK1 in PD pathogenesis.

Targeting PINK1 Using Natural Products for the Treatment of Human Diseases

PINK1, also known as PARK6, is a PTEN-induced putative kinase 1 that is encoded by nuclear genes. PINK1 is ubiquitously expressed and regulates mitochondrial function and mitophagy in a range of cell types. The dysregulation of PINK1 is associated with the pathogenesis and development of mitochondrial-associated disorders. Many natural products could regulate PINK1 to relieve PINK1-associated diseases. Here, we review the structure and function of PINK1, its relationship to human diseases, and the regulation of natural products to PINK1. We further highlight that the discovery of natural PINK1 regulators represents an attractive strategy for the treatment of PINK1-related diseases, including liver and heart diseases, cancer, and Parkinson's disease. Moreover, investigating PINK1 regulation of natural products can enhance the in-depth comprehension of the mechanism of action of natural products.

Astrocyte dysfunction in Parkinson's disease: from the perspectives of transmitted α-synuclein and genetic modulation

Parkinson's disease (PD) is a common neurodegenerative disorder that primarily affects the elderly. While the etiology of PD is likely multifactorial with the involvement of genetic, environmental, aging and other factors, α-synuclein (α-syn) pathology is a pivotal mechanism underlying the development of PD. In recent years, astrocytes have attracted considerable attention in the field. Although astrocytes perform a variety of physiological functions in the brain, they are pivotal mediators of α-syn toxicity since they internalize α-syn released from damaged neurons, and this triggers an inflammatory response, protein degradation dysfunction, mitochondrial dysfunction and endoplasmic reticulum stress. Astrocytes are indispensable coordinators in the background of several genetic mutations, including PARK7, GBA1, LRRK2, ATP13A2, PINK1, PRKN and PLA2G6. As the most abundant glial cells in the brain, functional astrocytes can be replenished and even converted to functional neurons. In this review, we discuss astrocyte dysfunction in PD with an emphasis on α-syn toxicity and genetic modulation and conclude that astrocyte replenishment is a valuable therapeutic approach in PD.

Astrocytes, a Promising Opportunity to Control the Progress of Parkinson's Disease

At present, there is no efficient treatment to prevent the evolution of Parkinson’s disease (PD). PD is generated by the concurrent activity of multiple factors, which is a serious obstacle for the development of etio-pathogenic treatments. Astrocytes may act on most factors involved in PD and the promotion of their neuroprotection activity may be particularly suitable to prevent the onset and progression of this basal ganglia (BG) disorder. The main causes proposed for PD, the ability of astrocytes to control these causes, and the procedures that can be used to promote the neuroprotective action of astrocytes will be commented upon, here.

Impaired Mitophagy in Neurons and Glial Cells during Aging and Age-Related Disorders

Aging is associated with a decline in cognitive function, which can partly be explained by the accumulation of damage to the brain cells over time. Neurons and glia undergo morphological and ultrastructure changes during aging. Over the past several years, it has become evident that at the cellular level, various hallmarks of an aging brain are closely related to mitophagy. The importance of mitochondria quality and quantity control through mitophagy is highlighted by the contribution that defects in mitochondria-autophagy crosstalk make to aging and age-related diseases. In this review, we analyze some of the more recent findings regarding the study of brain aging and neurodegeneration in the context of mitophagy. We discuss the data on the dynamics of selective autophagy in neurons and glial cells during aging and in the course of neurodegeneration, focusing on three mechanisms of mitophagy: non-receptor-mediated mitophagy, receptor-mediated mitophagy, and transcellular mitophagy. We review the role of mitophagy in neuronal/glial homeostasis and in the molecular pathogenesis of neurodegenerative disorders, such as Parkinson's disease, Alzheimer's disease, and other disorders. Common mechanisms of aging and neurodegeneration that are related to different mitophagy pathways provide a number of promising targets for potential therapeutic agents.

The Role of Pink1-Mediated Mitochondrial Pathway in Propofol-Induced Developmental Neurotoxicity

The mechanisms underlying propofol-induced toxicity in developing neurons are still unclear. The aim of present study was to explore the role of Pink1 mediated mitochondria pathway in propofol-induced developmental neurotoxicity. The primary Neural Stem Cells (NSCs) were isolated from the hippocampus of E15.5 mice embryos and then treated with propofol. The effects of propofol on proliferation, differentiation, apoptosis, mitochondria ultrastructure and MMP of NSCs were investigated. In addition, the abundance of Pink1 and a group of mitochondria related proteins in the cytoplasm and/or mitochondria were investigated, which mainly included CDK1, Drp1, Parkin1, DJ-1, Mfn1, Mfn2 and OPA1. Moreover, the relationship between Pink1 and these molecules was explored using gene silencing, or pretreatment with protein inhibitors. Finally, the NSCs were pretreated with mitochondrial specific antioxidant (MitoQ) or Drp1 inhibitor (Mdivi-1), and then the toxic effects of propofol on NSCs were investigated. Our results indicated that propofol treatment inhibited NSCs proliferation and division, and promoted NSCs apoptosis. Propofol induced significant NSCs mitochondria deformation, vacuolization and swelling, and decreased MMP. Additional studies showed that propofol affected a group of mitochondria related proteins via Pink1 inhibition, and CDK1, Drp1, Parkin1 and DJ-1 are the important downstream proteins of Pink1. Finally, the effects of propofol on proliferation, differentiation, apoptosis, mitochondrial ultrastructure and MMP of NSCs were significantly attenuated by MitoQ or Mdivi-1 pretreatment. The present study demonstrated that propofol regulates the proliferation, differentiation and apoptosis of NSCs via Pink1mediated mitochondria pathway.

MiR-421 Binds to PINK1 and Enhances Neural Stem Cell Self-Renewal via HDAC3-Dependent FOXO3 Activation

Dysfunctions of neural stem cells (NSCs) often lead to a variety of neurological diseases. Thus, therapies based on NSCs have gained increasing attention recently. It has been documented that microRNA (miR)-421 represses the autophagy and apoptosis of mouse hippocampal neurons and confers a role in the repair of ischemic brain injury (IBI). Herein, we aimed to illustrate the effects of miR-421 on NSC self-renewal. The downstream factors of miR-421 were predicted initially, followed by gain- and loss-of-function assays to examine their effects on NSC self-renewal. Immunoprecipitation and dual luciferase assays were conducted to validate the interaction among miR-421, PTEN-induced putative kinase 1 (PINK1), HDAC3, and forkhead box O3 (FOXO3). A mouse model with IBI was developed to substantiate the impact of the miR-421/PINK1/HDAC3/FOXO3 axis on NSC self-renewal. The expression of miR-421 was downregulated during differentiation of human embryonic NSCs, and miR-421 overexpression accelerated NSC self-renewal. Besides, miR-421 targeted PINK1 and restricted its expression in NSCs and further suppressed HDAC3 phosphorylation and enhanced FOXO3 acetylation. In conclusion, our data elucidated that miR-421 overexpression may facilitate NSC self-renewal through the PINK1/HDAC3/FOXO3 axis, which may provide potential therapeutic targets for the development of novel therapies for IBI.

Perinatal Inflammation Reprograms Neuroendocrine, Immune, and Reproductive Functions: Profile of Cytokine Biomarkers

Viral and bacterial infections causing systemic inflammation are significant risk factors for developing body. Inflammatory processes can alter physiological levels of regulatory factors and interfere with developmental mechanisms. The brain is the main target for the negative impact of inflammatory products during critical ontogenetic periods. Subsequently, the risks of various neuropsychiatric diseases such as Alzheimer's and Parkinson's diseases, schizophrenia, and depression are increased in the offspring. Inflammation-induced physiological disturbances can cause immune and behavioral disorders, reproductive deficiencies, and infertility. The influence of maternal immune stress is mediated by the regulation of pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, monocyte chemotactic protein 1, leukemia-inhibiting factor, and tumor necrosis factor-alpha secretion in the maternal-fetal system. The increasing number of patients with neuronal and reproductive disorders substantiates the identification of biomarkers for these disorders targeted at their therapy.

The PINK1-Mediated Crosstalk between Neural Cells and the Underlying Link to Parkinson's Disease

Mitochondrial dysfunction has a fundamental role in the development of idiopathic and familiar forms of Parkinson’s disease (PD). The nuclear-encoded mitochondrial kinase PINK1, linked to familial PD, is responsible for diverse mechanisms of mitochondrial quality control, ATP production, mitochondrial-mediated apoptosis and neuroinflammation. The main pathological hallmark of PD is the loss of dopaminergic neurons. However, novel discoveries have brought forward the concept that a disruption in overall brain homeostasis may be the underlying cause of this neurodegeneration disease. To sustain this, astrocytes and microglia cells lacking PINK1 have revealed increased neuroinflammation and deficits in physiological roles, such as decreased wound healing capacity and ATP production, which clearly indicate involvement of these cells in the physiopathology of PD. PINK1 executes vital functions within mitochondrial regulation that have a detrimental impact on the development and progression of PD. Hence, in this review, we aim to broaden the horizon of PINK1-mediated phenotypes occurring in neurons, astrocytes and microglia and, ultimately, highlight the importance of the crosstalk between these neural cells that is crucial for brain homeostasis.

Cleaved PINK1 induces neuronal plasticity through PKA-mediated BDNF functional regulation

Mutations in PTEN-induced kinase 1 (PINK1) lead to early onset autosomal recessive Parkinson's disease in humans. In healthy neurons, full-length PINK1 (fPINK1) is post-translationally cleaved into different lower molecular weight forms, and cleaved PINK1 (cPINK1) gets shuttled to the cytosolic compartments to support extra-mitochondrial functions. While numerous studies have exemplified the role of mitochondrially localized PINK1 in modulating mitophagy in oxidatively stressed neurons, little is known regarding the physiological role of cPINK1 in healthy neurons. We have previously shown that cPINK1, but not fPINK1, modulates the neurite outgrowth and the maintenance of dendritic arbors by activating downstream protein kinase A (PKA) signaling in healthy neurons. However, the molecular mechanisms by which cPINK1 promotes neurite outgrowth remain to be elucidated. In this report, we show that cPINK1 supports neuronal development by modulating the expression and extracellular release of brain-derived neurotrophic factor (BDNF). Consistent with this role, we observed a progressive increase in the level of endogenous cPINK1 but not fPINK1 during prenatal and postnatal development of mouse brains and during development in primary cortical neurons. In cultured primary neurons, the pharmacological activation of endogenous PINK1 leads to enhanced downstream PKA activity, subsequent activation of the PKA-modulated transcription factor cAMP response element-binding protein (CREB), increased intracellular production and extracellular release of BDNF, and enhanced activation of the BDNF receptor-TRKβ. Mechanistically, cPINK1-mediated increased dendrite complexity requires the binding of extracellular BDNF to TRKβ. In summary, our data support a physiological role of cPINK1 in stimulating neuronal development by activating the PKA-CREB-BDNF signaling axis in a feedforward loop.

The Pathogenesis of Parkinson's Disease: A Complex Interplay Between Astrocytes, Microglia, and T Lymphocytes?

Parkinson's disease (PD), the second most common neurodegenerative disease, is characterised by the motor symptoms of bradykinesia, rigidity and resting tremor and non-motor symptoms of sleep disturbances, constipation, and depression. Pathological hallmarks include neuroinflammation, degeneration of dopaminergic neurons in the substantia nigra pars compacta, and accumulation of misfolded α-synuclein proteins as intra-cytoplasmic Lewy bodies and neurites. Microglia and astrocytes are essential to maintaining homeostasis within the central nervous system (CNS), including providing protection through the process of gliosis. However, dysregulation of glial cells results in disruption of homeostasis leading to a chronic pro-inflammatory, deleterious environment, implicated in numerous CNS diseases. Recent evidence has demonstrated a role for peripheral immune cells, in particular T lymphocytes in the pathogenesis of PD. These cells infiltrate the CNS, and accumulate in the substantia nigra, where they secrete pro-inflammatory cytokines, stimulate surrounding immune cells, and induce dopaminergic neuronal cell death. Indeed, a greater understanding of the integrated network of communication that exists between glial cells and peripheral immune cells may increase our understanding of disease pathogenesis and hence provide novel therapeutic approaches.

PINK1 Activation Attenuates Impaired Neuronal-Like Differentiation and Synaptogenesis and Mitochondrial Dysfunction in Alzheimer's Disease Trans-Mitochondrial Cybrid Cells

BACKGROUND

Mitochondrial dysfunction, bioenergetic deficit, and extensive oxidative stress underlie neuronal perturbation during the early stage of Alzheimer's disease (AD). Previously, we demonstrated that decreased PTEN-induced putative kinase 1 (PINK1) expression is associated with AD pathology in AD-affected human brains and AD mice.

OBJECTIVE

In the present study, we highlight the essential role of PINK1 in AD-relevant mitochondrial perturbation and neuronal malfunction.

METHODS

Using trans-mitochondrial "cybrid" (cytoplasmic hybrid) neuronal cells, whose mitochondria are transferred from platelets of patients with sporadic AD, we observed the effect of PINK1 in neuronal-like differentiation and synaptogenesis and mitochondrial functions.

RESULTS

In AD cybrid cells, the downregulation of PINK1 is correlated to the alterations in mitochondrial morphology and function and deficit in neuronal-like differentiation. Restoring/increasing PINK1 by lentivirus transduction of PINK1 robustly attenuates mitochondrial defects and rescues neurite-like outgrowth. Importantly, defective PINK1 kinase activity fails to reverse these detrimental effects. Mechanistically, AD cybrid cells reveal a significant decrease in PINK1-dependent phosphorylated mitofusin (Mfn) 2, a key mitochondrial membrane protein that participates in mitochondrial fusion, and an insufficient autophagic activity for the clearance of dysfunctional mitochondria. Overexpression of PINK1, but not mutant PINK1 elevates phosphorylation of Mfn2 and autophagy signaling LC3-II. Accordingly, PINK1-overexpressed AD cybrids exhibit increases in mitochondrial length and density and suppressed reactive oxygen species. These results imply that activation of PINK1 protects against AD-affected mitochondrial dysfunction and impairment in neuronal maturation and differentiation.

CONCLUSION

PINK1-mediated mitophagy is important for maintaining mitochondrial health by clearance of dysfunctional mitochondria and therefore, improves energy homeostasis in AD.

Neuron-Astrocyte Interactions in Parkinson's Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disease. PD patients exhibit motor symptoms such as akinesia/bradykinesia, tremor, rigidity, and postural instability due to a loss of nigrostriatal dopaminergic neurons. Although the pathogenesis in sporadic PD remains unknown, there is a consensus on the involvement of non-neuronal cells in the progression of PD pathology. Astrocytes are the most numerous glial cells in the central nervous system. Normally, astrocytes protect neurons by releasing neurotrophic factors, producing antioxidants, and disposing of neuronal waste products. However, in pathological situations, astrocytes are known to produce inflammatory cytokines. In addition, various studies have reported that astrocyte dysfunction also leads to neurodegeneration in PD. In this article, we summarize the interaction of astrocytes and dopaminergic neurons, review the pathogenic role of astrocytes in PD, and discuss therapeutic strategies for the prevention of dopaminergic neurodegeneration. This review highlights neuron-astrocyte interaction as a target for the development of disease-modifying drugs for PD in the future.

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.

Microglia and astrocyte dysfunction in parkinson's disease

While glia are essential for regulating the homeostasis in the normal brain, their dysfunction contributes to neurodegeneration in many brain diseases, including Parkinson's disease (PD). Recent studies have identified that PD-associated genes are expressed in glial cells as well as neurons and have crucial roles in microglia and astrocytes. Here, we discuss the role of microglia and astrocytes dysfunction in relation to PD-linked mutations and their implications in PD pathogenesis. A better understanding of microglia and astrocyte functions in PD may provide insights into neurodegeneration and novel therapeutic approaches for PD.

Application of electrospun polycaprolactone fibers embedding lignin nanoparticle for peripheral nerve regeneration: In vitro and in vivo study

Lignin displays attractive properties in peripheral nerve applications. Here, aligned polycaprolactone (PCL) fibers with various percentages of lignin nanoparticles were fabricated using the electrospinning method. The morphologies, contact angles, mechanical properties, in vitro degradation, and water uptake of the PCL/lignin fibers were characterized. Cell viability and adhesion of PC12 and human adipose-derived stem cells (hADSCs) were studied employing MTT assay and SEM, respectively. SEM, immunocytochemistry, and Real-Time PCR were utilized to characterize neural differentiation and neurite length of PC12 and hADSCs. To further study on lignin effect on nerve regeneration, in vivo studies were performed. The results indicated that all nanocomposite fibers were smooth and bead-free. With increasing the lignin content, the water contact angle decreased while in vitro degradation, water uptake, and Young's modulus increased compared to the PCL fibers. Cell viability, and differentiation along with neurite length extension were promoted by increasing lignin content. The neural markers expression for differentiated cells were upregulated by the increase of lignin percent. In vivo investigation also demonstrates that sample groups incorporating 15% lignin nanoparticles showed better regeneration among others. Therefore, PCL with 15% of lignin nanoparticles shows great potential to be applied for nerve regeneration.

Critical roles of astrocytic-CCL2-dependent monocyte infiltration in a DJ-1 knockout mouse model of delayed brain repair

Monocyte-derived macrophages play a role in the repair of the injured brain. We previously reported that a deficiency of the Parkinson's disease (PD)-associated gene DJ-1 delays repair of brain injury produced by stereotaxic injection of ATP, a component of damage-associated molecular patterns. Here, we show that a DJ-1 deficiency attenuates monocyte infiltration into the damaged brain owing to a decrease in C-C motif chemokine ligand 2 (CCL2) expression in astrocytes. Like DJ-1-knockout (KO) mice, CCL2 receptor (CCR2)-KO mice showed defects in monocyte infiltration and delayed recovery of brain injury, as determined by 9.4 T magnetic resonance imaging analysis and immunostaining for tyrosine hydroxylase and glial fibrillary acid protein. Notably, transcriptome analyses showed that genes related to regeneration and synapse formation were similarly downregulated in injured brains of DJ-1-KO and CCR2-KO mice compared with the injured wild-type brain. These results indicate that defective astrogliosis in DJ-1-KO mice is associated with decreased CCL2 expression and attenuated monocyte infiltration, resulting in delayed repair of brain injury. Thus, delayed repair of brain injury could contribute to the development of PD. MAIN POINTS: A DJ-1 deficiency attenuates infiltration of monocytes owing to a decrease in CCL2 expression in astrocytes, which in turn led to delay in repair of brain injury.

Paroxetine suppresses reactive microglia-mediated but not lipopolysaccharide-induced inflammatory responses in primary astrocytes

BACKGROUND

Astrocytes are the most abundant glial cells in a brain that mediate inflammatory responses and provide trophic support for neurons. We have previously disclosed that paroxetine, a common selective serotonin reuptake inhibitor, ameliorates LPS-induced microglia activation. However, it remains elusive for the role of paroxetine in astrocytic responses.

METHODS

Isolated primary astrocytes were pretreated with paroxetine and stimulated with different stimuli, lipopolysaccharide (LPS) or microglia conditioned medium pre-activated with LPS (M/Lps). Inflammatory and neurotrophic responses, underlying mechanisms and the impact on neuronal survival were assessed.

RESULTS

Paroxetine had no impact on LPS-stimulated iNOS, TNF-α, and IL-1β expression, but inhibited M/Lps-induced TNF-α and IL-1β expression in primary astrocytes. Paroxetine suppressed M/Lps- but not LPS-induced activation of NF-κB and had no impact on the activation of MAPKs and STAT3. Incubation with the resulted astrocyte conditioned media caused no change in the viability of SH-SY5Y cells. BDNF and MANF mRNA expressions were upregulated by M/Lps and paroxetine, respectively. However, M/Lps- or LPS-induced extracellular releases of NO, TNF-α, and/or BDNF in astrocytes were in minor amount compared to those by microglia.

CONCLUSIONS

Paroxetine ameliorates the reactive microglia-mediated inflammatory responses in astrocytes partially via inhibition of the NF-κB pathway but has no impact on LPS-stimulated astrocyte activation. While the effects of paroxetine on secondary astrocytic responses are not robust compared to its effect on the innate immune responses of microglia, the results together may implicate a therapeutic potential of paroxetine against neuroinflammation-associated neurological disorders such as Parkinson's disease.

PINK1 phosphorylates ubiquitin predominantly in astrocytes

Loss-of-function mutations in PINK1 are causally linked to recessively inherited Parkinson’s disease (PD), with marked loss of dopaminergic neurons in the substantia nigra that are required for normal movement. PINK1 is a nuclear-encoded mitochondrial-targeted kinase that phosphorylates a conserved serine at amino acid 65 (pS65) in ubiquitin as well as Parkin, another gene with loss-of-function mutations linked to recessive parkinsonism. The steady-state levels of PINK1 protein are very low, even in cells that express PINK1, because PINK1 is normally targeted for degradation after mitochondrial import by a process that is dependent upon mitochondrial membrane potential. Dissipation of the mitochondrial membrane potential with ionophores, such as CCCP and valinomycin, causes the accumulation of PINK1 on the outer mitochondrial membrane, a marked increase of pS65-ubiquitin and the recruitment of Parkin, which targets dysfunctional mitochondria for degradation by autophagy. While the high penetrance of PINK1 mutations establish its critical function for maintaining neurons, the activity of PINK1 in primary neurons has been difficult to detect. Mounting evidence implicates non-neuronal cells, including astrocytes and microglia, in the pathogenesis of both idiopathic and inherited PD. Herein we used both western analysis and immunofluorescence of pS65-ubiquitin to directly compare the activity of PINK1 in primary neurons, astrocytes, microglia, and oligodendrocyte progenitor cells cultured from the brains of wild-type (WT) and PINK1 knockout (KO) rat pups. Our findings that PINK1-dependent ubiquitin phosphorylation is predominantly in astrocytes supports increased priority for research on the function of PINK1 in astrocytes and the contribution of astrocyte dysfunction to PD pathogenesis.

Neuroinflammation and Glial Phenotypic Changes in Alpha-Synucleinopathies

The role of neuroinflammation has been increasingly recognized in the field of neurodegenerative diseases. Many studies focusing on the glial cells involved in the inflammatory responses of the brain, namely microglia and astroglia, have over the years pointed out the dynamic and changing behavior of these cells, accompanied by different morphologies and activation forms. This is particularly evident in diseased conditions, where glia react to any shift from homeostasis, acquiring different phenotypes. Particularly for microglia, it has soon become clear that such phenotypes are multiple, as multiple are the functions related to them. Several approaches have over time revealed different facets of microglial phenotypic diversity, and advanced genetic analyses, in recent years, have added new insights into microglial heterogeneity, opening novel scenarios that researchers have just started to explore. Among neurodegenerative diseases, an important section is represented by alpha-synucleinopathies. Here alpha-synuclein accumulates abnormally in the brain and, depending on its pattern of distribution, leads to the development of different clinical conditions. Also for these proteinopathies, neuroinflammation and glial activation have been identified as constant and crucial factors during disease development. In the present review we will address the current literature about glial phenotypic changes with respect to alpha-synucleinopathies, as well as consider the pathophysiological and therapeutic implications of such a dynamic cellular behavior.

The Role of Astrocytes in the Central Nervous System Focused on BK Channel and Heme Oxygenase Metabolites: A Review

Astrocytes outnumber neurons in the human brain, and they play a key role in numerous functions within the central nervous system (CNS), including glutamate, ion (i.e., Ca²⁺, K⁺) and water homeostasis, defense against oxidative/nitrosative stress, energy storage, mitochondria biogenesis, scar formation, tissue repair via angiogenesis and neurogenesis, and synapse modulation. After CNS injury, astrocytes communicate with surrounding neuronal and vascular systems, leading to the clearance of disease-specific protein aggregates, such as β-amyloid, and α-synuclein. The astrocytic big conductance K⁺ (BK) channel plays a role in these processes. Recently, potential therapeutic agents that target astrocytes have been tested for their potential to repair the brain. In this review, we discuss the role of the BK channel and antioxidant agents such as heme oxygenase metabolites following CNS injury. A better understanding of the cellular and molecular mechanisms of astrocytes’ functions in the healthy and diseased brains will greatly contribute to the development of therapeutic approaches following CNS injury, such as Alzheimer’s disease, Parkinson’s disease, and stroke.

PRDX6 Inhibits Neurogenesis through Downregulation of WDFY1-Mediated TLR4 Signal

Impaired neurogenesis has been associated with several brain disorders, such as Alzheimer's disease (AD) and Parkinson's disease (PD). The role of peroxiredoxin 6 (PRDX6) in neurodegenerative diseases is very controversial. To demonstrate the role of PRDX6 in neurogenesis, we compared the neurogenesis ability of PRDX6-overexpressing transgenic (Tg) mice and wild-type mice and studied the involved molecular mechanisms. We showed that the neurogenesis of neural stem cells (NSCs) and the expression of the marker protein were lower in PRDX6 Tg-mice than in wild-type mice. To determine the factors involved in PRDX6-related neural stem cell impairment, we performed a microarray experiment. We showed that the expression of WDFY1 was dramatically decreased in PRDX6-Tg mice. Moreover, WDFY1 siRNA decreases the differentiation ability of primary neural stem cells. Interestingly, WDFY1 reportedly recruits the signaling adaptor TIR-domain-containing adapter-inducing interferon-β (TRIF) to toll-like receptors (TLRs); thus, we showed the relationship among TLRs, PRDX6, and WDFY1. We showed that TLR4 was dramatically reduced in PRDX6 Tg mice, and reduced TLR4 expression and neurogenesis was reversed by the introduction of WDFY1 plasmid in the neural stem cells from PRDX6 Tg mice. This study indicated that PRDX6 inhibits the neurogenesis of neural precursor cells through TLR4-dependent downregulation of WDFY1 and suggested that the inhibitory effect of PRDX6 on neurogenesis play a role in the development of neurodegenerative diseases in the PRDX6 overexpressing transgenic mice.

Mitochondrial contributions to neuronal development and function

Mitochondria are critical to tissues and organs characterized by high-energy demands, such as the nervous system. They provide essential energy and metabolites, and maintain Ca2+ balance, which is imperative for proper neuronal function and development. Emerging findings further underline the role of mitochondria in neurons. Technical advances in the last decades made it possible to investigate key mechanisms in neuronal development and the contribution of mitochondria therein. In this article, we discuss the latest findings relevant to the involvement of mitochondria in neuronal development, placing emphasis on mitochondrial metabolism and dynamics. In addition, we survey the role of mitochondrial energy metabolism and Ca2+ homeostasis in proper neuronal function, and the involvement of mitochondria in axon myelination.

Are we listening to everything the PARK genes are telling us?

The cardinal motor symptoms that define Parkinson's disease (PD) clinically have been recognized for over 200 years. That these symptoms arise following the loss of dopamine neurons in the substantia nigra has been known for the last 50. These long-established facts have fueled a broadly held expectation that degenerating dopaminergic neurons alone hold the key to understanding and curing PD. This prevalent expectation is at odds with the observation that many nonmotor symptoms, including depression and cognitive inflexibility among others, can appear years earlier than the overt dopaminergic neuron degeneration that drives motor abnormalities and are not improved by levodopa treatment. Thus, preserving or rescuing dopamine neuron health and function is of paramount importance, but this alone fails to capture the underlying neurobiology of earlier-appearing nonmotor symptoms. Insight into the complete landscape of disease-related abnormalities and the context in which they arise can be gleaned from a more comprehensive consideration of the PARK genes that are known to cause PD. Here, we make the case that a full incorporation of research showing when and where PARK genes are expressed as well as the impact of gene mutation on function throughout life, in tandem with research studying how dopaminergic neuron degeneration begins, is essential for a full understanding of the multi-dimensional etiology of PD. A broad view may also reveal something about long-term adjustments cells and systems make in response to gene mutation and help to identify mechanisms conferring the resilience or susceptibility of some cells and systems over others.

Astrocyte-Like Cells Differentiated from Dental Pulp Stem Cells Protect Dopaminergic Neurons Against 6-Hydroxydopamine Toxicity

Dental pulp stem cells (DPSCs) are promising for use in neurodegenerative-diseases because of their neural crest origin. While neuronal differentiation of DPSCs has been shown, their plasticity towards astrocyte-like cells remains to be studied. We aimed to examine differentiation potential of DPSCs to astrocytes and their consequent neuroprotective role towards dopaminergic (DA) neurons under 6-hydroxydopamine (6-OHDA) toxicity. Induction of DPSCs to astrocytes with differentiation factors showed definitive increase in astrocyte-specific markers glial fibrillary acidic protein (GFAP), and excitatory amino acid transporter 2 along with glial calcium-binding protein S100β through FACS and immunofluorescence assays. RT-PCR and ELISA showed significant increase in BDNF and GDNF expression and secretion in astrocyte-differentiated DPSCs over naïve DPSCs. Neuroprotective role of these cells on DA neurons under 6-OHDA stress was evaluated by both contact and non-contact methods. FACS analysis of PKH26-stained SH-SY5Y homogenous cells in contact method and of TH immunopositive cells in primary midbrain culture in non-contact method both indicated higher survival of DA neurons in astrocyte-differentiated DPSCs over naïve DPSCs. Recovery of β-tubulin III and TH immunopositive cells was reduced in the presence of TrkB inhibitor, suggesting a key neuroprotective role of BDNF secretion by DPSCs. When nitric oxide (NO) release was inhibited by L-NAME in primary midbrain culture, BDNF release in co-culture under 6-OHDA stress reduced further in naïve DPSCs than in astrocyte-differentiated DPSCs, suggesting that BDNF release in naïve DPSCs is primarily regulated by paracrine signaling while for differentiated DPSCs, it is equally through autocrine and paracrine signaling with NO being the mediator. In conclusion, we suggest that DPSCs exposed to glial commitment cues exhibit substantial differentiation towards astrocyte-like cells with better neuroprotective activity against 6-OHDA toxicity than naïve DPSCs.

Astrocytes, Microglia, and Parkinson's Disease

Astrocytes and microglia support well-being and well-function of the brain through diverse functions in both intact and injured brain. For example, astrocytes maintain homeostasis of microenvironment of the brain through up-taking ions and neurotransmitters, and provide growth factors and metabolites for neurons, etc. Microglia keep surveying surroundings, and remove abnormal synapses or respond to injury by isolating injury sites and expressing inflammatory cytokines. Therefore, their loss and/or functional alteration may be directly linked to brain diseases. Since Parkinson's disease (PD)-related genes are expressed in astrocytes and microglia, mutations of these genes may alter the functions of these cells, thereby contributing to disease onset and progression. Here, we review the roles of astrocytes and microglia in intact and injured brain, and discuss how PD genes regulate their functions.

HACE1 is essential for astrocyte mitochondrial function and influences Huntington disease phenotypes in vivo

Oxidative stress is a prominent feature of Huntington disease (HD), and we have shown previously that reduced levels of hace1 (HECT domain and Ankyrin repeat containing E3 ubiquitin protein ligase 1) in patient striatum may contribute to the pathogenesis of HD. Hace1 promotes the stability of Nrf2 and thus plays an important role in antioxidant response mechanisms, which are dysfunctional in HD. Moreover, hace1 overexpression mitigates mutant huntingtin (mHTT)-induced oxidative stress in vitro through promotion of the Nrf2 antioxidant response. Here, we show that the genetic ablation of hace1 in the YAC128 mouse model of HD accelerates motor deficits and exacerbates cognitive and psychiatric phenotypes in vivo. We find that both the expression of mHTT and the ablation of hace1 alone are sufficient to cause deficits in astrocytic mitochondrial respiration. We confirm the crucial role of hace1 in astrocytes in vivo, since its ablation is sufficient to cause dramatic astrogliosis in wild-type FVB/N mice. Astrogliosis is not observed in the presence of mHTT but a strong dysregulation in the expression of astrocytic markers in HACE1-/- x YAC128 striatum suggests an additive effect of mHTT expression and hace1 loss on this cell type. HACE1-/- x YAC128 mice and primary cells derived from these animals therefore provide model systems that will allow for the further dissection of Nrf2 pathways and astrocyte dysfunction in the context of HD.

A Parkinson's disease gene, DJ-1, repairs brain injury through Sox9 stabilization and astrogliosis

Defects in repair of damaged brain accumulate injury and contribute to slow-developing neurodegeneration. Here, we report that a deficiency of DJ-1, a Parkinson's disease (PD) gene, delays repair of brain injury due to destabilization of Sox9, a positive regulator of astrogliosis. Stereotaxic injection of ATP into the brain striatum produces similar size of acute injury in wild-type and DJ-1-knockout (KO) mice. However, recovery of the injury is delayed in KO mice, which is confirmed by 9.4T magnetic resonance imaging and tyrosine hydroxylase immunostaining. DJ-1 regulates neurite outgrowth from damaged neurons in a non-cell autonomous manner. In DJ-1 KO brains and astrocytes, Sox9 protein levels are decreased due to enhanced ubiquitination, resulting in defects in astrogliosis and glial cell-derived neurotrophic factor/ brain-derived neurotrophic factor expression in injured brain and astrocytes. These results indicate that DJ-1 deficiency causes defects in astrocyte-mediated repair of brain damage, which may contribute to the development of PD.

Regulatory Role of Redox Balance in Determination of Neural Precursor Cell Fate

In 1990s, reports of discovery of a small group of cells capable of proliferation and contribution to formation of new neurons in the central nervous system (CNS) reversed a century-old concept on lack of neurogenesis in the adult mammalian brain. These cells are found in all stages of human life and contribute to normal cellular turnover of the CNS. Therefore, the identity of regulating factors that affect their proliferation and differentiation is a highly noteworthy issue for basic scientists and their clinician counterparts for therapeutic purposes. The cues for such control are embedded in developmental and environmental signaling through a highly regulated tempo-spatial expression of specific transcription factors. Novel findings indicate the importance of reactive oxygen species (ROS) in the regulation of this signaling system. The elusive nature of ROS signaling in many vital processes from cell proliferation to cell death creates a complex literature in this field. Here, we discuss the emerging thoughts on the importance of redox regulation of proliferation and maintenance in mammalian neural stem and progenitor cells under physiological and pathological conditions. The current knowledge on ROS-mediated changes in redox-sensitive proteins that govern the molecular mechanisms in proliferation and differentiation of these cells is reviewed.

Astrocytes in a dish: Using pluripotent stem cells to model neurodegenerative and neurodevelopmental disorders

Neuroscience and Neurobiology have historically been neuron biased, yet up to 40% of the cells in the brain are astrocytes. These cells are heterogeneous and regionally diverse but universally essential for brain homeostasis. Astrocytes regulate synaptic transmission as part of the tripartite synapse, provide metabolic and neurotrophic support, recycle neurotransmitters, modulate blood flow and brain blood barrier permeability and are implicated in the mechanisms of neurodegeneration. Using pluripotent stem cells (PSC), it is now possible to study regionalised human astrocytes in a dish and to model their contribution to neurodevelopmental and neurodegenerative disorders. The evidence challenging the traditional neuron-centric view of degeneration within the CNS is reviewed here, with focus on recent findings and disease phenotypes from human PSC-derived astrocytes. In addition we compare current protocols for the generation of regionalised astrocytes and how these can be further refined by our growing knowledge of neurodevelopment. We conclude by proposing a functional and phenotypical characterisation of PSC-derived astrocytic cultures that is critical for reproducible and robust disease modelling.

The Role of Astrocyte Dysfunction in Parkinson's Disease Pathogenesis

Astrocytes are the most populous glial subtype and are critical for brain function. Despite this, historically there have been few studies into the role that they may have in neurodegenerative diseases, such as Parkinson's disease (PD). Recently, however, several studies have determined that genes known to have a causative role in the development of PD are expressed in astrocytes and have important roles in astrocyte function. Here, we review these recent developments and discuss their impact on our understanding of the pathophysiology of PD, and the implications that this might have for its treatment.

Eat, breathe, ROS: controlling stem cell fate through metabolism

INTRODUCTION

Research reveals cardiac regeneration exists at levels previously deemed unattainable. Clinical trials using stem cells demonstrate promising cardiomyogenic and regenerative potential but insufficient contractile recovery. Incomplete understanding of the biology of administered cells likely contributes to inconsistent patient outcomes. Metabolism is a core component of many well-characterized stem cell types, and metabolic changes fundamentally alter stem cell fate from self-renewal to lineage commitment, and vice versa. However, the metabolism of stem cells currently studied for cardiac regeneration remains incompletely understood. Areas covered: Key metabolic features of stem cells are reviewed and unique stem cell metabolic characteristics are discussed. Metabolic changes altering stem cell fate are considered from quiescence and self-renewal to lineage commitment. Key metabolic concepts are applied toward examining cardiac regeneration through stem cell-based approaches, and clinical implications of current cell therapies are evaluated to identify potential areas of improvement. Expert commentary: The metabolism and biology of stem cells used for cardiac therapy remain poorly characterized. A growing appreciation for the fundamental relationship between stem cell functionality and metabolic phenotype is developing. Future studies unraveling links between cardiac stem cell metabolism and regenerative potential may considerably improve treatment strategies and therapeutic outcomes.

PINK1 Deficiency Decreases Expression Levels of mir-326, mir-330, and mir-3099 during Brain Development and Neural Stem Cell Differentiation

PTEN-induced putative kinase 1 (PINK1) is a Parkinson's disease (PD) gene. We examined miRNAs regulated by PINK1 during brain development and neural stem cell (NSC) differentiation, and found that lvels of miRNAs related to tumors and inflammation were different between 1-day-old-wild type (WT) and PINK1-knockout (KO) mouse brains. Notably, levels of miR-326, miR-330 and miR-3099, which are related to astroglioma, increased during brain development and NSC differentiation, and were significantly reduced in the absence of PINK1. Interestingly, in the presence of ciliary neurotrophic factor (CNTF), which pushes differentiation of NSCs into astrocytes, miR-326, miR-330, and miR-3099 levels in KO NSCs were also lower than those in WT NSCs. Furthermore, mimics of all three miRNAs increased expression of the astrocytic marker glial fibrillary acidic protein (GFAP) during differentiation of KO NSCs, but inhibitors of these miRNAs decreased GFAP expression in WT NSCs. Moreover, these miRNAs increased the translational efficacy of GFAP through the 3'-UTR of GFAP mRNA. Taken together, these results suggest that PINK1 deficiency reduce expression levels of miR-326, miR-330 and miR-3099, which may regulate GFAP expression during NSC differentiation and brain development.