Loss of function mutations in the gene encoding Omi/HtrA2 in Parkinson’s disease. Hum Mol Genet
Ruhr-Universität Bochum, Bochum, North Rhine-Westphalia, Germany Human Molecular Genetics
(Impact Factor: 6.39).
09/2005; 14(15):2099-111. DOI: 10.1093/hmg/ddi215
Recently targeted disruption of Omi/HtrA2 has been found to cause neurodegeneration and a parkinsonian phenotype in mice.
Using a candidate gene approach, we performed a mutation screening of the Omi/HtrA2 gene in German Parkinson's disease (PD) patients. In four patients, we identified a novel heterozygous G399S mutation, which
was absent in healthy controls. Moreover, we identified a novel A141S polymorphism that was associated with PD (P<0.05). Both mutations resulted in defective activation of the protease activity of Omi/HtrA2. Immunohistochemistry and functional
analysis in stably transfected cells revealed that S399 mutant Omi/HtrA2 and to a lesser extent, the risk allele of the A141S
polymorphism induced mitochondrial dysfunction associated with altered mitochondrial morphology. Cells overexpressing S399
mutant Omi/HtrA2 were more susceptible to stress-induced cell death than wild-type. On the basis of functional genomics, our
results provide a novel link between mitochondrial dysfunction and neurodegeneration in PD.
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Available from: Dwaipayan Sen
- "The activity of HTRA2/OMI is regulated by phosphorylation by PINK1 (Plun-Favreau et al. 2007). Finally, loss-of-function mutations in OMI/HTRA2 have been associated with PD incidence in a human population (Strauss et al. 2005). Interestingly mutations in the MT folding chaperone HSP70 also associate with PD and expression of these mutant alleles affect MT function in cell models (Fig. 4) (Burbulla et al. 2010). "
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ABSTRACT: Parkinson’s disease is the second most common neurodegenerative disease which affects almost 1% of the population above the age of 60. It is is characterized by loss of dopaminergic neurons in the striatum and substantia nigra, coupled with the formation of intracellular Lewy bodies in degenerating neurons. Recent evidence suggests endoplasmic reticulum stress as a common and prominent occurrence in the progression of Parkinson’s disease pathogenesis in the affected human brain. One of the cellular defense mechanism to combat endoplasmic reticulum stress due to excessive protein accumulation is through activation of the unfolded protein response pathway. In this review we focus on the impact and role of this unfolded protein response as a causative factor of Parkinson’s disease leading to neurodegeneration.
Available from: George Anderson
- "fungicides, herbicides, pesticides, and metals  . Mutations in a number of genes are associated with both familial and sporadic forms of PD, including alpha-synuclein, Parkin and many others    . How such environmental and genetic risk factors drive the etiological and biological underpinnings of PD, such as oxidative and nitrosative stress (O&NS), mitochondrial dysfunction, peripheral and central inflammation, as well as immune driven changes awaits clarification. "
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ABSTRACT: Increased depression, somatization, gut inflammation and wider peripheral inflammation are all associated with the early stages of Parkinson's disease (PD). Classically such concurrent conditions have been viewed as "comorbidities", driven by high levels of stress in a still poorly understood and treated disorder. Here we review the data on how oxidative and nitrosative stress in association with immuno-inflammatory responses, drives alteration in tryptophan catabolites, including kynurenine, kynurenic acid and quinolinic acid that drive not only the "comorbidities" of PD but also important processes in the etiology and course of PD per se. The induction of indoleamine 2,3-dioxygenase, leading to the driving of tryptophan into neuroregulatory tryptophan catabolite products and away from serotonin and melatonin production, has significant implications for understanding the role of nicotine, melatonin, and caffeine in regulating PD susceptibility. Tryptophan catabolite pathway activation will also regulate blood-brain barrier permeability, glia and mast cell reactivity as well as wider innate and adaptive immune cell responses, all relevant to the course of PD. As such, the "comorbidities" of PD such as depression, somatization and peripheral inflammatory disorders can all be conceptualized as being an intricate part of the biological underpinnings of both the etiology and course of PD. As a consequence, the data reviewed here has treatment implications; relevant to both the course of PD and in the management of L-DOPA induced dyskinesias.
Available from: Caroline Meharg
- "The serine peptidase coded by Htra2 gene is located in the mitochondrial intermembrane space. It activates proapoptotic proteins upon release into the cytosol from damaged mitochondria . Interestingly, in addition to the T449D polymorphism, the transcript abundance of the gene tended to be higher in the SM/J strain (p=0.13; "
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We have recently identified a number of Quantitative Trait Loci (QTL) contributing to the 2-fold muscle weight difference between the LG/J and SM/J mouse strains and refined their confidence intervals. To facilitate nomination of the candidate genes responsible for these differences we examined the transcriptome of the tibialis anterior (TA) muscle of each strain by RNA-Seq.
13,726 genes were expressed in mouse skeletal muscle. Intersection of a set of 1061 differentially expressed transcripts with a mouse muscle Bayesian Network identified a coherent set of differentially expressed genes that we term the LG/J and SM/J Regulatory Network (LSRN). The integration of the QTL, transcriptome and the network analyses identified eight key drivers of the LSRN (Kdr, Plbd1, Mgp, Fah, Prss23, 2310014F06Rik, Grtp1, Stk10) residing within five QTL regions, which were either polymorphic or differentially expressed between the two strains and are strong candidates for quantitative trait genes (QTGs) underlying muscle mass. The insight gained from network analysis including the ability to make testable predictions is illustrated by annotating the LSRN with knowledge-based signatures and showing that the SM/J state of the network corresponds to a more oxidative state. We validated this prediction by NADH tetrazolium reductase staining in the TA muscle revealing higher oxidative potential of the SM/J compared to the LG/J strain (p<0.03).
Thus, integration of fine resolution QTL mapping, RNA-Seq transcriptome information and mouse muscle Bayesian Network analysis provides a novel and unbiased strategy for nomination of muscle QTGs.
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