Project description:The maintenance of mitochondrial homeostasis requires PTEN-induced kinase 1 (PINK1)-dependent mitophagy, and mutations in PINK1 are associated with Parkinson's disease (PD). PINK1 is also downregulated in tumor cells with PTEN mutations. However, there is limited information concerning the role of PINK1 in tissue growth and tumorigenesis. Here, we show that loss of pink1 caused multiple growth defects independent of its pathological target, Parkin. Moreover, knocking-down pink1 in muscle cells induced hyperglycemia and limited systemic organismal growth by induction of Imaginal morphogenesis protein-Late 2 (ImpL2). Similarly, disrupting PTEN activity in multiple tissues impaired systemic growth by reducing pink1 expression, resembling wasting-like syndrome in cancer patients. Furthermore, re-expression of PINK1 fully rescued defects in carbohydrate metabolism and systemic growth induced by the tissue-specific pten mutations. Our data suggest a new function for PINK1 in regulating systemic growth in Drosophila, and shed light on its role in wasting in context of PTEN mutations.
Project description:PTEN plays a crucial role in preventing the development of glioblastoma (GBM), a severe and untreatable brain cancer. In GBM, most PTEN deficiencies arise from missense mutations, many of which have not been thoroughly examined. Here, we leveraged genetically modified mice and matched isogenic astrocyte cell cultures to investigate how specific and clinically relevant PTEN mutations (G36E, L42R, C105F, and R173H) behave in the development of GBM driven by EGFR. We report that the tumor-suppressive abilities of these PTEN mutants do not depend on their ability to act as lipid phosphatases but are instead related to their increased presence at the cell membrane. Moreover, these PTEN mutations led to heightened EGFR activity by keeping EGFR within endomembranes longer, affecting its signaling behavior. Through comprehensive studies on global protein phosphorylation and kinase library analyses in cells with the G36E and L42R PTEN mutations, we identified distinct cancer-promoting pathways activated by EGFR, offering new targets for treating GBM with these PTEN alterations.
Project description:PTEN-induced kinase 1 (PINK1) is a very short-lived protein that is required for the removal of damaged mitochondria through Parkin translocation and mitophagy. Because the short half-life of PINK1 limits its ability to be trafficked into neurites, local translation is required for this mitophagy pathway to be active far from the soma. The Pink1 transcript is associated with and cotransported with neuronal mitochondria. In concert with translation, the mitochondrial outer membrane protein Synaptojanin 2 Binding Protein (SYNJ2BP) and Synaptojanin 2 (SYNJ2) are required for tethering Pink1 mRNA to mitochondria via an RNA-binding domain in SYNJ2. This neuron-specific adaptation for local translation of PINK1 provides distal mitochondria with a continuous supply of PINK1 for activation of mitophagy.
Project description:Parkinson's Disease (PD) is primarily caused by aggregates of alpha synuclein (SNCA) in dopaminergic neurons of the substantia nigra, but PD is a systemic disease and may lead to PD-associated dementia complex. PD-associated encephalopathy is a late manifestation in PD patients at risk for example owing to mutations of the lysosomal enzyme glucocerebrosidase. Defects of lysosomal waste removal and aggregation of mutant alpha synuclein (SNCA) impacts of the proteome. Here, we studied the proteome of the prefrontal cortex in Pink1-/-SNCA A53T double mutant mice in comparison with their wildtype controls. Pink1-/-SNCA A53T mice carry a loss of function knock-in mutation of PTEN induced kinase (Pink1), plus the human A53T mutation of alpha synuclein (SNCA-A53T) [1, 2]. Homozygous Pink1-/-SNCA A53T double mutant mice were generated by crossing Pink1-/- mice (background: 129/SvEv) with A53T-SNCA-overexpressing PrPmtA mice (background: FVB/N) and then, interbreeding the littermates. Wildtype (WT) control mice are hybrids from a crossbreeding of 129/SvEv and FVB/N mice, which were descended from littermates of the respective single mutant animals. Pink1-/-SNCA A53T mice develop spontaneous motor symptoms at advanced ages, with a progressive incidence above 15 months of age. The phenotype of Pink1-/-SNCA A53T and wildtype control mice was observed during aging. Mice were euthanized at an age of 1-1.5 years (matched with the controls). The cortices were rapidly removed and frozen in liquid nitrogen and processed for label free proteomic analyses.
Project description:The PTEN tumor suppressor controls cell death and survival by regulating functions of various molecular targets. Whilst the role of PTEN lipid-phosphatase activity on PtdIns(3,4,5)P3 and inhibition of PI3K pathway is well characterized, the biological relevance of PTEN protein-phosphatase activity remains undefined. Using knock-in (KI) mice harbouring cancer-associated and functionally relevant missense mutations, we show that although loss of PTEN lipid-phosphatase function cooperates with oncogenic PI3K to promote rapid mammary tumorigenesis, the additional loss of PTEN protein-phosphatase activity triggered an extensive cell death response evident in early and advanced mammary tumors. Omics and drug-targeting studies revealed that PI3Ks act to reduce glucocorticoid receptor (GR) levels, which are rescued by loss of PTEN protein-phosphatase activity to restrain cell survival. The dual regulation of GR by PI3K and PTEN functions as a rheostat that can be exploited for the treatment of PTEN-loss driven cancers.
Project description:Loss of function in the PTEN-induced kinase 1 gene (Pink1) causes an early-onset, autosomal recessive form of PD. The translational Pink1-/- rat shows cranial sensorimotor deficits including: declines in ultrasonic vocalization, negative impacts on social vocal function, and alterations to thyroarytenoid muscle structure. The aim of this study was to identify differentially expressed genes using RNA-sequencing and bioinformatic analysis of the thyroarytenoid muscle of male Pink1-/- rats compared to wildtype controls. To construct gene co-expression networks and gene modules, a WGCNA was used to identify biological networks of interest including where Pink1 was a central node with interconnecting genes. Data are congruent with previous findings demonstrating changes to thyroarytenoid muscle structure. These data are consistent with the hypothesis that differences in peripheral biology may influence the early pathogenesis of vocalizations at the level of the thyroarytenoid muscle.
Project description:Th17-related genes increased in T cells from PINK1-deficient mice. Th17 and Treg cells were increased and decreased in PINK1-deficient cells, respectively, and phosphorylation of signal transducer and activator of transcription 3 (STAT3) was increased in PINK1-deficient cells.
Project description:In this study, we aimed to explore the impact of PINK1 deficiency on MSC differentiation and bone health within the context of age-related bone loss, with a particular focus on the mechanisms regulating the balance between osteogenesis and adipogenesis. By examining how PINK1 influences bone health in both young and aged mice, we hope to gain a deeper understanding of the age-specific roles of PINK1 in skeletal bone maintenance and explore the possibility of targeting PINK1 to mitigate osteoporosis in the aging population.
Project description:Parkinson's disease (PD) is an adult-onset movement disorder of largely unknown etiology. We have previously shown that loss-of-function mutations of the mitochondrial protein kinase PINK1 (PTEN induced putative kinase 1) cause the recessive PARK6 variant of PD. Now we generated a PINK1 deficient mouse and observed several novel phenotypes: A progressive reduction of weight and of locomotor activity selectively for spontaneous movements occurred at old age. As in PD, abnormal dopamine levels in the aged nigrostriatal projection accompanied the reduced movements. Possibly in line with the PARK6 syndrome but in contrast to sporadic PD, a reduced lifespan, dysfunction of brainstem and sympathetic nerves, visible aggregates of M-NM-1-synuclein within Lewy bodies or nigrostriatal neurodegeneration were not present in aged PINK1-deficient mice. However, we demonstrate PINK1 mutant mice to exhibit a progressive reduction in mitochondrial preprotein import correlating with defects of core mitochondrial functions like ATP-generation and respiration. In contrast to the strong effect of PINK1 on mitochondrial dynamics in Drosophila melanogaster and in spite of reduced expression of fission factor Mtp18, we show reduced fission and increased aggregation of mitochondria only under stress in PINK1-deficient mouse neurons. Thus, aging Pink1M-bM-^HM-^R/M-bM-^HM-^R mice show increasing mitochondrial dysfunction resulting in impaired neural activity similar to PD, in absence of overt neuronal death. Transcriptome microarray data of Pink1-/- mouse brains in absence of a stressor, even at old age, show remarkably sparse dysregulations. See Gispert-S et al 2009 PLOS ONE. Factorial design comparing Pink1 knock-out mice with wild type littermates in three different tissues (striatum, midbrain, cerebellum at four different timepoints (6, 12, 14 weeks, and 18 month)
Project description:Parkinson's disease (PD) is an adult-onset movement disorder of largely unknown etiology. We have previously shown that loss-of-function mutations of the mitochondrial protein kinase PINK1 (PTEN induced putative kinase 1) cause the recessive PARK6 variant of PD. Now we generated a PINK1 deficient mouse and observed several novel phenotypes: A progressive reduction of weight and of locomotor activity selectively for spontaneous movements occurred at old age. As in PD, abnormal dopamine levels in the aged nigrostriatal projection accompanied the reduced movements. Possibly in line with the PARK6 syndrome but in contrast to sporadic PD, a reduced lifespan, dysfunction of brainstem and sympathetic nerves, visible aggregates of α-synuclein within Lewy bodies or nigrostriatal neurodegeneration were not present in aged PINK1-deficient mice. However, we demonstrate PINK1 mutant mice to exhibit a progressive reduction in mitochondrial preprotein import correlating with defects of core mitochondrial functions like ATP-generation and respiration. In contrast to the strong effect of PINK1 on mitochondrial dynamics in Drosophila melanogaster and in spite of reduced expression of fission factor Mtp18, we show reduced fission and increased aggregation of mitochondria only under stress in PINK1-deficient mouse neurons. Thus, aging Pink1−/− mice show increasing mitochondrial dysfunction resulting in impaired neural activity similar to PD, in absence of overt neuronal death. Transcriptome microarray data of Pink1-/- mouse brains in absence of a stressor, even at old age, show remarkably sparse dysregulations. See Gispert-S et al 2009 PLOS ONE.