PTEN-induced Putative Kinase 1 Gene Research Articles

Characterization and function of PTEN-induced putative kinase 1 (PINK1) in process of Zinc alleviates hepatic lipid deposition of yellow catfish (Pelteobagrus fulvidraco)

PTEN-induced putative kinase 1 (PINK1) is a key regulator of mitophagy, however, the relevant information remains poorly understood on aquatic animals. Here, a PINK1 gene was cloned, characterized and functionally studied in yellow catfish. PINK1 encoded a protein containing 570 amino acids, 2 functional domains. High fat (15.66%) fed fish showed a downregulation trend of liver PINK1 expression than that of normal fat (10.14%) group, and was reversed by the addition of Zn. In the in vitro study, high fat (HF) can increase lipid deposition and decrease by addition Zn (HFZ) in hepatocytes, whereas above phenomena reversed by overexpression/interference of PINK1, respectively. In addition, the addition of Zn can significantly affect mitochondrial activity, increase mitophagy, and improve the antioxidant activity of hepatocytes. Together, these findings illustrated that yellow catfish PINK1 is conserve, and it participated in mitochondria control of fish. These findings indicate Zn could alleviate high fat-induced hepatic lipid deposition of fish by activating PINK1-mediated mitophagy and provide basis for further exploring new approach for decreasing lipid deposition in fish products during aquaculture.

PINK1 mediated mitophagy attenuates early apoptosis of gingival epithelial cells induced by high glucose

BackgroundOxidative stress mediated by hyperglycemia damages cell-reparative processes such as mitophagy. Down-regulation of mitophagy is considered to be a susceptible factor for diabetes mellitus (DM) and its complications. However, the role of mitophagy in DM-associated periodontitis has not been fully elucidated. Apoptosis of human gingival epithelial cells (hGECs) is one of the representative events of DM-associated periodontitis. Thus, this study aimed to investigate PTEN-induced putative kinase 1 (PINK1)-mediated mitophagy activated in the process of high glucose (HG)-induced hGECs apoptosis.MethodsFor dose–response studies, hGECs were incubated in different concentrations of glucose (5.5, 15, 25, and 50 mmol/L) for 48 h. Then, hGECs were challenged with 25 mmol/L glucose for 12 h and 48 h, respectively. Apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL), caspase 9 and mitochondrial membrane potential (MMP). Subsequently, autophagy was evaluated by estimating P62, LC3 II mRNA levels, LC3 fluorescent puncta and LC3-II/I ratio. Meanwhile, the involvement of PINK1-mediated mitophagy was assessed by qRT-PCR, western blotting and immunofluorescence. Finally, hGECs were transfected with shPINK1 and analyzed by MMP, caspase 9 and annexin V-FITC apoptosis.ResultsThe number of TUNEL-positive cells and caspase 9 protein were significantly increased in cells challenged with HG (25 mmol/L) for 48 h (HG 48 h). MMP was impaired both at HG 12 h and HG 48 h, but the degree of depolarization was more serious at HG 48 h. The autophagy improved as the amount of LC3 II increased and p62 decreased in HG 12 h. During this process, HG 12 h treatment induced PINK1-mediated mitophagy. PINK1 silencing with HG 12 h resulted in MMP depolarization and cell apoptosis.ConclusionsThese results suggested that loss of the PINK1 gene may cause mitochondrial dysfunction and increase sensitivity to HG-induced apoptosis of hGECs at the early stage. PINK1 mediated mitophagy attenuates early apoptosis of gingival epithelial cells induced by high glucose.

Rosiglitazone Ameliorates Spinal Cord Injury via Inhibiting Mitophagy and Inflammation of Neural Stem Cells.

Background Neurodegenerative diseases, such as Alzheimer's disease, and traumatic brain and spinal cord injury (SCI) are prevalent in clinical practice. Inhibition of hyperactive inflammation and proliferation of endogenous neural stem cells (NSCs) is a promising treatment strategy for SCI. Our previous studies demonstrated the beneficial effects of rosiglitazone (Rosi) on SCI, but its roles in inflammation inhibition and proliferation of NSCs are unknown. Methods SCI in a rat model was established, and the effects of Rosi on motor functions were assessed. The effects of Rosi on NSC proliferation and the underlying mechanisms were explored in details. Results We showed that Rosi ameliorated impairment of moto functions in SCI rats, inhibited inflammation, and promoted proliferation of NSCs in vivo. Rosi increased ATP production through enhancing glycolysis but not oxidative phosphorylation. Rosi reduced mitophagy by downregulating PTEN-induced putative kinase 1 (PINK1) transcription to promote NSC proliferation, which was effectively reversed by an overexpression of PINK1 in vitro. Through KEGG analysis and experimental validations, we discovered that Rosi reduced the expression of forkhead box protein O1 (FOXO1) which was a critical transcription factor of PINK1. Three FOXO1 consensus sequences (FCSs) were found in the first intron of the PINK1 gene, which could be potentially binding to FOXO1. The proximal FCS (chr 5: 156680169–156680185) from the translation start site exerted a more significant influence on PINK1 transcription than the other two FCSs. The overexpression of FOXO1 entirely relieved the inhibition of PINK1 transcription in the presence of Rosi. Conclusions Besides inflammation inhibition, Rosi suppressed mitophagy by reducing FOXO1 to decrease the transcription of PINK1, which played a pivotal role in accelerating the NSC proliferation.

Disruption of Mitochondrial Homeostasis: The Role of PINK1 in Parkinson's Disease.

The progressive reduction of the dopaminergic neurons of the substantia nigra is the fundamental process underlying Parkinson’s disease (PD), while the mechanism of susceptibility of this specific neuronal population is largely unclear. Disturbances in mitochondrial function have been recognized as one of the main pathways in sporadic PD since the finding of respiratory chain impairment in animal models of PD. Studies on genetic forms of PD have provided new insight on the role of mitochondrial bioenergetics, homeostasis, and autophagy. PINK1 (PTEN-induced putative kinase 1) gene mutations, although rare, are the second most common cause of recessively inherited early-onset PD, after Parkin gene mutations. Our knowledge of PINK1 and Parkin function has increased dramatically in the last years, with the discovery that a process called mitophagy, which plays a key role in the maintenance of mitochondrial health, is mediated by the PINK1/Parkin pathway. In vitro and in vivo models have been developed, supporting the role of PINK1 in synaptic transmission, particularly affecting dopaminergic neurons. It is of paramount importance to further define the role of PINK1 in mitophagy and mitochondrial homeostasis in PD pathogenesis in order to delineate novel therapeutic targets.

In search of early neuroradiological biomarkers for Parkinson’s Disease: Alterations in resting state functional connectivity and gray matter microarchitecture in PINK1 −/− rats

Parkinson’s Disease (PD) is the second most common neurodegenerative disorder, with 60,000 new cases diagnosed each year in the US. There are multiple animal models of PD that attempt to mimic the effects of the disease through genetic alteration. Combined with advanced imaging techniques, these animal models are critical in tracking the neurobiological and behavioral aspects of disease progression and identifying early biomarkers of PD. PTEN-induced putative kinase 1 (PINK1) is a mitochondrial protein kinase involved in protecting neurons from stress-induced mitochondrial dysfunction. A mutation in the PINK1 gene that alters its function can increase the risk for autosomal recessive familial PD and similarly, through genetic deletion of portions of the PINK1 gene in animal models (i.e., “PINK1 knock-out (−/−) rats) produces a progressive loss of dopaminergic neurons in the substantia nigra which is analogous to the pathological hallmarks in human PD patients. In this exploratory study, we used volumetric analysis, resting-state functional connectivity MRI (rs-fcMRI) and diffusion-weighted imaging (DWI) to identify neurobiological differences between wild-type (WT) and PINK1 (−/−) rats. All voxel-based measures for each modality were registered to a rat MRI atlas with 171 segmented and annotated brain regions allowing for the measurement of subtle changes in brain function and architecture that go well beyond typical clinical MRI scanning protocols. Basal ganglia, the mesencephalic dopamine system, the limbic cortex, and the hippocampal complex showed changes in putative gray matter microarchitecture, reflected by shifts in quantitative anisotropy. Rs-fcMRI revealed altered resting state connectivity in many brain areas including the basal ganglia, amygdala, cortex, septum, pons etc. Taken together, these results inform us on a wide range of whole-brain changes occurring in a PD rat model in the absence of cognitive and motor deficits, serving as potential biomarkers and targets for treatment.

PPAR-γ Agonist Promotes Proliferation of Neural Stem Cells Via Mitophagy Inhibition

Background: Proliferation of neural stem cells (NSCs) is crucial for recovery from spinal cord injury (SCI). The effect of PPAR-γ agonist on SCI recovery and the way it regulating NSCs proliferation are both unknown. Methods: The effects of PPAR-γ agonist (rosiglitazone) treatment on recovery from SCI and proliferation of NSCs were confirmed. The roles of mitophagy and PTEN induced putative kinase 1 (PINK1) in rosiglitazoneinduced proliferation of NSCs were explored. Details mechanisms on the transcription regulation of PINK1 by rosiglitazone were addressed. Findings: Rosiglitazone independently increased the proportion of Nestin /Brdu cells in the spinal cord and motor function of SCI rats. It reduced mitophagy and expression of PTEN induced putative kinase 1 (PINK1) in NSCs. The forkhead box protein O1 (FOXO1) was identified as the transcription factor mostly altered by rosiglitazone. Restoration of FOXO1 expression antagonized the effects of rosiglitazone on mitophagy and PINK1 expression. The FOXO1 consensus sequence (FCS) was not identified upstream of the PINK1 transcription start site, but three FCSs were found in the first intron of the PINK1 gene. All of the FCSs participated in the regulation of PINK1 transcription upon treatment with rosiglitazone and expression of FOXO1 but the proximal FCS (chr 5: 156680169-156680185, 3022 bp counting from the translation start site) exerted greater influence. Conclusions: PPAR-γ agonist could be a promising therapeutic strategy for spinal cord injury. Funding Statement:This work was supported by the National Natural Science Foundation of China (Grant No. 81870334, 81301038, 81300071, 81300279 and 81741067); the Science and Technology Program of Guangdong (Grant No. 2015A020212029); and the Science and Technology Program of Guangzhou City (Grant No. 201510010048, 201607010009, 201607010010 and 201804010050). Declaration of Interests: All authors declare no potential conflict of interest. Ethics Approval Statement: All of the animal experiments complied with the ARRIVE guidelines, and they were carried out in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals (NIH Publication No. 8023, revised 1978)

ATF3 represses PINK1 gene transcription in lung epithelial cells to control mitochondrial homeostasis.

Summary PINK1 (PTEN‐induced putative kinase 1) is a key regulator of mitochondrial homeostasis that is relatively depleted in aging lungs and in lung epithelial cells from patients with idiopathic pulmonary fibrosis (IPF), a disease linked with aging. Impaired PINK1 expression and accumulation of damaged mitochondria in lung epithelial cells from fibrotic lungs were associated with the presence of ER stress. Here, we show that ATF3 (activating transcription factor 3), a member of the integrated stress response (ISR), negatively regulates transcription of the PINK1 gene. An ATF3 binding site within the human PINK1 promoter is located in the first 150 bp upstream of the transcription start site. Induction of ER stress or overexpression of ATF3 inhibited the activity of the PINK1 promoter. Importantly, overexpression of ATF3 causes accumulation of depolarized mitochondria, increased production of mitochondrial ROS, and loss of cell viability. Furthermore, conditional deletion of ATF3 in type II lung epithelial cells protects mice from bleomycin‐induced lung fibrosis. Finally, we observed that ATF3 expression increases in the lung with age and, specially, in lung epithelial cells from IPF lungs. These data provide a unique link between ATF3 and PINK1 expression suggesting that persistent stress, driven by ATF3, can dysregulate mitochondrial homeostasis by repression of PINK1 mRNA synthesis.

Characterization of a presymptomatic stage in a Drosophila Parkinson's disease model: Unveiling dopaminergic compensatory mechanisms

Parkinson's disease (PD) is a degenerative disorder characterized by several motor symptoms including shaking, rigidity, slow movement and difficult walking, which has been associated to the death of nigro-striatal dopaminergic neurons. >90% of PD patients also present olfactory dysfunction. Although the molecular mechanisms responsible for this disease are not clear, hereditary PD is linked to mutations in specific genes, including the PTEN-induced putative kinase 1 (PINK1).In this work we provide for the first time a thorough temporal description of the behavioral effects induced by a mutation in the PINK1 gene in adult Drosophila, a previously described animal model for PD. Our data suggests that the motor deficits associated to PD are fully revealed only by the third week of age. However, olfactory dysfunction is detected as early as the first week of age. We also provide immunofluorescence and neurochemical data that let us propose for the first time the idea that compensatory changes occur in this Drosophila model for PD. These compensatory changes are associated to specific components of the dopaminergic system: the biosynthetic enzymes, Tyrosine hydroxylase and Dopa decarboxylase, and the Dopamine transporter, a plasma membrane protein involved in maintaining dopamine extracellular levels at physiologically relevant levels.Thus, our behavioral, immunofluorescence and neurochemical data help define for the first time presymptomatic and symptomatic phases in this PD animal model, and that compensatory changes occur in the dopaminergic neurons in the presymptomatic stage.

Twenty years since the discovery of the parkin gene.

Nearly 20years have passed since we identified the causative gene for a familial Parkinson's disease, parkin (now known as PARK2), in 1998. PARK2 is the most common gene responsible for young-onset Parkinson's disease. It codes for the protein Parkin RBR E3 ubiquitin-protein ligase (PARK2), which directly links to the ubiquitin-proteasome as a ubiquitin ligase. PARK2 is involved in mitophagy, which is a type of autophagy, in collaboration with PTEN-induced putative kinase 1 (PINK1). The PINK1 gene (previously known as PARK6) is also a causative gene for young-onset Parkinson's disease. Both gene products may be involved in regulating quality control within the mitochondria. The discovery of PARK2 as a cause of young-onset Parkinson's disease has had a major impact on other neurodegenerative diseases. The involvement of protein degradation systems has been implicated as a common mechanism for neurodegenerative diseases in which inclusion body formation is observed. The discovery of the involvement of PARK2 in Parkinson's disease focused attention on the involvement of protein degradation systems in neurodegenerative diseases. In this review, we focus on the history of the discovery of PARK2, the clinical phenotypes of patients with PARK2 mutations, and its functional roles.

Loss of PINK1 inhibits apoptosis by upregulating α-synuclein in inflammation-sensitized hypoxic-ischemic injury in the immature brains

The incidence of preterm birth is rising worldwide. Among preterm infants, many face a lifetime of neurologic impairments. Recent studies have revealed that systemic inflammation can sensitize the immature brain to hypoxic-ischemic (HI) injury. Therefore, it is important to identify the mechanisms involved in inflammation-sensitized HI injury in immature brains. PTEN-induced putative kinase 1 (PINK1) is a regulatory protein that is highly expressed in the brain. We have previously found that PINK1 gene knockout can protect matured brains from HI injury in postnatal day 10 mice. However, the mechanisms are unknown. In this study, we employed an inflammation-sensitized HI injury model using postnatal day 3 mice to study the roles and mechanisms that PINK1 plays in the immature brains. Lipopolysaccharide (LPS) was injected intraperitoneally into the mice before HI treatment to set up the model. We found that PINK1-knockout mice had fewer brain infarcts and less cell apoptosis than did the wild-type mice. Furthermore, we found that α-synuclein was markedly higher in the PINK1-knockout mice than in the wild-type mice, and inhibition of α-synuclein through small interfering RNA (siRNA) reversed the protective effect in the PINK1-knockout mice. Collectively, these findings indicate that loss of PINK1 plays a novel role in the protection of inflammation-sensitized HI brain damage.

P.1.a.007 - Monoamine oxidase A (MAOA) gene hypomethylation in panic disorder − an epigenetic risk pattern reversed by psychotherapy?

Parkinson's disease (PD) is a degenerative disorder characterized by several motor symptoms including shaking, rigidity, slow movement and difficult walking, which has been associated to the death of nigro-striatal dopaminergic neurons. > 90% of PD patients also present olfactory dysfunction. Although the molecular mechanisms responsible for this disease are not clear, hereditary PD is linked to mutations in specific genes, including the PTEN-induced putative kinase 1 (PINK1).In this work we provide for the first time a thorough temporal description of the behavioral effects induced by a mutation in the PINK1 gene in adult Drosophila, a previously described animal model for PD. Our data suggests that the motor deficits associated to PD are fully revealed only by the third week of age. However, olfactory dysfunction is detected as early as the first week of age. We also provide immunofluorescence and neurochemical data that let us propose for the first time the idea that compensatory changes occur in this Drosophila model for PD. These compensatory changes are associated to specific components of the dopaminergic system: the biosynthetic enzymes, Tyrosine hydroxylase and Dopa decarboxylase, and the Dopamine transporter, a plasma membrane protein involved in maintaining dopamine extracellular levels at physiologically relevant levels.Thus, our behavioral, immunofluorescence and neurochemical data help define for the first time presymptomatic and symptomatic phases in this PD animal model, and that compensatory changes occur in the dopaminergic neurons in the presymptomatic stage.

NRF2 Regulates PINK1 Expression under Oxidative Stress Conditions.

Mutations of the PTEN-induced putative kinase 1 (PINK1) gene are a cause of autosomal recessive forms of Parkinson’s disease. Recent studies have revealed that PINK1 is an essential factor for controlling mitochondrial quality, and that it protects cells from oxidative stresses. Although there has been considerable progress in the elucidation of various aspects of PINK1 protein regulation such as activation, stability and degradation, the transcriptional regulation of PINK1 mRNA under stress conditions remains unclear. In this study, we found that nuclear factor (erythroid-derived 2)-like 2 (NRF2), an antioxidant transcription factor, regulates PINK1 expression under oxidative stress conditions. Damaged mitochondria arising from stress conditions induced NRF2-dependent transcription of the PINK1 gene through production of reactive oxygen species (ROS). Either an ROS scavenger or forced expression of KEAP1, a potent inhibitory partner to NRF2, restricted PINK1 expression induced by activated NRF2. Transcriptionally up-regulated PINK1 diminished oxidative stress-associated cell death. The results indicate that PINK1 expression is positively regulated by NRF2 and that the NRF2-PINK1 signaling axis is deeply involved in cell survival.

Ultrasound‐based motion analysis demonstrates bilateral arm hypokinesia during gait in heterozygous PINK1 mutation carriers

Carriers of a single heterozygous PINK1 (PTEN-induced putative kinase 1) gene mutation provide an ideal opportunity to study the development of parkinsonian motor signs from the very beginning. Measuring tools that reliably represent mild motor symptoms could also facilitate the assessment of future neuroprotective therapies and early diagnosis of Parkinson's disease (PD). We investigated nine family members carrying a heterozygous PINK1 mutation in comparison with 25 age-matched healthy controls. Arm kinematics were quantified during treadmill walking at four different speeds using ultrasound-based motion analysis. Heterozygous PINK1 mutation carriers showed a bilateral reduction of arm swing amplitudes (P = 0.003) and arm anteversion (P = 0.001), which was more pronounced on the predominantly affected body side but also was present, albeit to a lesser degree, contralaterally (amplitude P = 0.01, anteversion P = 0.002, repeated measures analysis of covariance [rmANCOVA]). Single post-hoc comparisons revealed similar results for all speeds on both body sides (P < 0.05) except for 2.0 km/h on the less affected side. A single heterozygous mutation in the PINK1 gene is associated with a bilateral dopaminergic dysfunction in this family. Ultrasound-based three-dimensional motion analysis of arm swing during gait is a suitable tool to quantify even subtle hypokinesia in mildly affected PINK1 mutation carriers, which tends to be easily overlooked on the less affected body side during clinical examination. Therefore, this technique is a promising application in early stage PD and in at-risk populations for the disease.

Upregulation of human PINK1 gene expression by NFκB signalling.

Parkinson’s disease (PD) is one of the major neurodegenerative disorders. Mitochondrial malfunction is implicated in PD pathogenesis. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN)-induced putative kinase 1 (PINK1), a serine/threonine kinase, plays an important role in the quality control of mitochondria and more than 70 PINK1 mutations have been identified to cause early-onset PD. However, the regulation of PINK1 gene expression remains elusive. In the present study, we identified the transcription start site (TSS) of the human PINK1 gene using switching mechanism at 5’end of RNA transcription (SMART RACE) assay. The TSS is located at 91 bp upstream of the translation start site ATG. The region with 104 bp was identified as the minimal promoter region by deletion analysis followed by dual luciferase assay. Four functional cis-acting nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB)-binding sites within the PINK1 promoter were identified. NFκB overexpression led to the up-regulation of PINK1 expression in both HEK293 cells and SH-SY5Y cells. Consistently, lipopolysaccharide (LPS), a strong activator of NFκB, significantly increased PINK1 expression in SH-SY5Y cells. Taken together, our results clearly suggested that PINK1 expression is tightly regulated at its transcription level and NFκB is a positive regulator for PINK1 expression.

Detailed analysis of mitochondrial respiratory chain defects caused by loss of PINK1

Mutations in PTEN-induced putative kinase 1 (PINK1) cause recessive forms of Parkinson's disease (PD). PINK1 acts upstream of parkin, regulating mitochondrial elimination (mitophagy) in cultured cells treated with mitochondrial uncouplers that cause mitochondrial depolarization. PINK1 loss-of-function decreases mitochondrial membrane potential, resulting in mitochondrial dysfunction, although the exact function of PINK1 in mitochondria has not been fully elucidated. We have previously found that PINK1 deficiency causes a decrease in mitochondrial membrane potential, which is not due to a proton leak, but to respiratory chain defects. Here, we examine mitochondrial respiratory chain defects in PINK1-deficient cells, and find both complex I and complex III are defective. These results suggest that mitochondrial respiratory chain defects may be associated with PD pathogenesis caused by mutations in the PINK1 gene.

Juvenile-Onset Parkinsonism as a Result of the First Mutation in the Adenosine Triphosphate Orientation Domain of PINK1

Mutations in the PTEN-induced putative kinase 1 (PINK1) gene at 1p36 have been involved in autosomal recessive early-onset parkinsonism. To describe the clinical and genetic features of the largest kindred reported to date with early-onset parkinsonism associated with the PINK1 gene. Clinical and genetic study. Collaborative study. Patients Eight patients from Sudan with particularly early onset (ages 9-17 years) and phenotypes varying from dopa-responsive dystonia-like to typical early-onset parkinsonism. The PINK1 genotype and Parkinson disease status of all available family members. The disease was caused by a novel mutation, p.A217D, located in the highly conserved adenosine triphosphate orientation site of the PINK1 kinase domain. This study extends the phenotypic and molecular spectrum of the PINK1 gene and the geographic origin of patients with PINK1 gene mutations.