Dysbindin-1 is reduced in intrinsic, glutamatergic terminals of the hippocampal formation in schizophrenia

Talbot, Konrad; Eidem, Wess L.; Tinsley, Caroline L.; Benson, Matthew A.; Thompson, Edward W.; Smith, Rachel J.; Hahn, Chang-Gyu; Siegel, Steven J.; Trojanowski, John Q.; Gur, Raquel E.; Blake, Derek J.; Arnold, Steven E.

doi:10.1172/jci20425

Cited by 173 publications

(169 citation statements)

References 67 publications

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“…It is thus likely that the BLOC-1-dependent pathway that we have defined is ubiquitous in mammals, but it has been exploited by specialized cell types for delivery of specific cargo to LROs, such as melanosomes, platelet dense granules, and lung lamellar bodies, and/or to synaptic vesicles (McGarry et al, 2002;Talbot et al, 2004;Bray et al, 2005;Guttentag et al, 2005). Our data suggest that at least one critical cargo protein is targeted from early endosomes to each of these organelles in a BLOC-1-dependent manner.…”

Section: Discussionmentioning

confidence: 75%

BLOC-1 Is Required for Cargo-specific Sorting from Vacuolar Early Endosomes toward Lysosome-related Organelles

Setty

Tenza

Truschel

et al. 2007

MBoC

201

342

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Hermansky-Pudlak syndrome (HPS) is a genetic disorder characterized by defects in the formation and function of lysosome-related organelles such as melanosomes. HPS in humans or mice is caused by mutations in any of 15 genes, five of which encode subunits of biogenesis of lysosome-related organelles complex (BLOC)-1, a protein complex with no known function.Here, we show that BLOC-1 functions in selective cargo exit from early endosomes toward melanosomes. BLOC-1-deficient melanocytes accumulate the melanosomal protein tyrosinase-related protein-1 (Tyrp1), but not other melanosomal proteins, in endosomal vacuoles and the cell surface due to failed biosynthetic transit from early endosomes to melanosomes and consequent increased endocytic flux. The defects are corrected by restoration of the missing BLOC-1 subunit. Melanocytes from HPS model mice lacking a different protein complex, BLOC-2, accumulate Tyrp1 in distinct downstream endosomal intermediates, suggesting that BLOC-1 and BLOC-2 act sequentially in the same pathway. By contrast, intracellular Tyrp1 is correctly targeted to melanosomes in melanocytes lacking another HPS-associated protein complex, adaptor protein (AP)-3. The results indicate that melanosome maturation requires at least two cargo transport pathways directly from early endosomes to melanosomes, one pathway mediated by AP-3 and one pathway mediated by BLOC-1 and BLOC-2, that are deficient in several forms of HPS. INTRODUCTIONHermansky-Pudlak syndrome (HPS) is a genetic disorder characterized by hypopigmentation, prolonged bleeding, and sometimes ceroid accumulation, lung fibrosis, and/or immune defects leading to premature death Wei, 2006). HPS or a similar disorder in mice results from mutations in any of at least 15 genes (Wei, 2006). All of these genes are ubiquitously expressed, but their mutation in HPS affects mainly the generation and function of selected tissuespecific lysosome-related organelles (LROs;Bonifacino, 2004;Di Pietro and Dell'Angelica, 2005). Those LROs that are most severely affected in all forms of HPS-pigment cell melanosomes, platelet dense granules, and lung lamellar bodies-are unique in that they coexist with bona fide lysosomes in their respective cell types (Dell'Angelica et al., 2000;Marks and Seabra, 2001). The 15 known HPS-associated genes have been identified, and although the products of most are thought to participate in trafficking events that are uniquely required to form this class of LRO, the function of only a few is understood in detail.The genes disrupted in human HPS-7 (Li et al., 2003) and HPS-8 (Morgan et al., 2006) and in the mouse HPS models pallid, muted, reduced pigmentation (rp), cappuccino, and sandy encode five of the eight known subunits of a stable protein complex known as biogenesis of lysosome-related organelles complex (BLOC)-1 (Falcon-Perez et al., 2002;Moriyama and Bonifacino, 2002;Ciciotte et al., 2003;Li et al., 2003;Gwynn et al., 2004;Starcevic and Dell'Angelica, 2004). To date, no specific subcellular function has been assigned...

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Section: Discussionmentioning

confidence: 75%

BLOC-1 Is Required for Cargo-specific Sorting from Vacuolar Early Endosomes toward Lysosome-related Organelles

Setty

Tenza

Truschel

et al. 2007

MBoC

201

342

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“…However, these multipotent proteins have roles in multiple biological pathways that affect normal brain development as well as cognitive functions in the matured brain, and may contribute to a common pathophysiological 'lesion' that settles in after establishment of the illness. A common theme for DISC1, neuregulin1, and PSD95 is that manipulating these gene products impacts neuroplasticity, a core feature of the schizophrenia syndrome (McCullumsmith et al, 2004;Talbot et al, 2004).…”

Section: The Schizophrenia Phenotypementioning

confidence: 99%

Postmortem Brain: An Underutilized Substrate for Studying Severe Mental Illness

McCullumsmith

Hammond

Shan

et al. 2013

Neuropsychopharmacol

107

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We propose that postmortem tissue is an underutilized substrate that may be used to translate genetic and/or preclinical studies, particularly for neuropsychiatric illnesses with complex etiologies. Postmortem brain tissues from subjects with schizophrenia have been extensively studied, and thus serve as a useful vehicle for illustrating the challenges associated with this biological substrate. Schizophrenia is likely caused by a combination of genetic risk and environmental factors that combine to create a disease phenotype that is typically not apparent until late adolescence. The complexity of this illness creates challenges for hypothesis testing aimed at understanding the pathophysiology of the illness, as postmortem brain tissues collected from individuals with schizophrenia reflect neuroplastic changes from a lifetime of severe mental illness, as well as treatment with antipsychotic medications. While there are significant challenges with studying postmortem brain, such as the postmortem interval, it confers a translational element that is difficult to recapitulate in animal models. On the other hand, data derived from animal models typically provide specific mechanistic and behavioral measures that cannot be generated using human subjects. Convergence of these two approaches has led to important insights for understanding molecular deficits and their causes in this illness. In this review, we discuss the problem of schizophrenia, review the common challenges related to postmortem studies, discuss the application of biochemical approaches to this substrate, and present examples of postmortem schizophrenia studies that illustrate the role of the postmortem approach for generating important new leads for understanding the pathophysiology of severe mental illness.

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“…We observed the total expression of dysbindin-1 and NRG-1 (that is, the combined expression of all isoforms), which had previously been observed in a postmortem brain, 12,[14][15][16] to determine whether immortalized lymphocytes are a good tool to determine the effect of genetic risks of dysbindin-1 and NRG-1 on their expression and whether immortalized lymphocytes are an appropriate alternative to neuronal tissue.…”

Section: Introductionmentioning

confidence: 92%

“…13 Expression studies in postmortem brains have also revealed lower expression of dysbindin-1 and higher expression of NRG-1 type I, in subjects with schizophrenia. 12,[14][15][16] Postmortem brain tissues are necessary for determining the pathophysiology of schizophrenia. Many gene expression studies have been conducted using postmortem brain tissues.…”

Section: Introductionmentioning

confidence: 99%

Dysbindin-1 and NRG-1 gene expression in immortalized lymphocytes from patients with schizophrenia

et al. 2011

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The dysbindin-1 and neuregulin-1 (NRG-1) genes are related to schizophrenia. Expression studies in postmortem brains have revealed lower expression of dysbindin-1 and higher expression of NRG-1 in brain tissue from subjects with schizophrenia. In addition to the difficulty of sampling, the use of postmortem brain tissues is not ideal because these tissues are heterogeneous with respect to biochemical parameters, lifetime history of medications and physiological status at the time of death. In contrast, medication and environmental influences that could mask the genetic basis of differences in RNA expression are removed in immortalized lymphocytes by culturing. Only a few microarray analysis studies using immortalized lymphocytes in schizophrenia have been reported, and whether immortalized lymphocytes are an appropriate alternative to neuronal tissue remains controversial. In this study, we measured the mRNA expression levels of dysbindin-1, NRG-1 and two other genes (NPY1R and GNAO1) in immortalized lymphocytes from 45 patients with schizophrenia and 45 controls using real-time quantitative reverse transcriptase-PCR. No difference was observed between patients and controls with respect to the expression of dysbindin-1, NRG-1, NPY1R or GNAO1 gene. Our findings suggest that the gene expression profile of immortalized lymphocyte from schizophrenic patients is different from that in postmortem brain tissue at least with respect to the dysbindin-1 and NRG-1 genes. Journal of Human Genetics INTRODUCTIONSchizophrenia is a complex genetic disorder that is characterized by profound disturbances of cognition, emotion and social functioning. It affects B1% of the general population world wide. The dysbindin-1 and neuregulin-1 (NRG-1) genes are related to schizophrenia, 1 and the dysbindin-1 gene is also associated with cognitive functions. [2][3][4] Furthermore, the Sandy mouse, which expresses no dysbindin-1, has been reported to have behavioral abnormalities, cognitive deficits and a synaptic dysfunction that is related to the pathophysiology of schizophrenia. [5][6][7] Identified risk variants of NRG-1 are associated with the reduced white matter volume that is observed in schizophrenic brains. 8 The NRG-1 gene spans 1.2 Mb 9 and gives rise to many structurally and functionally distinct isoforms, through alternative promoter usage. These isoforms are divided into three classic groups: 10 type I (previously known as acetylcholine receptor inducing activity, heregulin or neu differentiation factor), type II (glia growth factor) and type III (cysteine-rich domain containing), which are based on distinct amino termini. Additional NRG-1 5¢ exons have

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Dysbindin-1 is reduced in intrinsic, glutamatergic terminals of the hippocampal formation in schizophrenia

Cited by 173 publications

References 67 publications

BLOC-1 Is Required for Cargo-specific Sorting from Vacuolar Early Endosomes toward Lysosome-related Organelles

BLOC-1 Is Required for Cargo-specific Sorting from Vacuolar Early Endosomes toward Lysosome-related Organelles

Postmortem Brain: An Underutilized Substrate for Studying Severe Mental Illness

Dysbindin-1 and NRG-1 gene expression in immortalized lymphocytes from patients with schizophrenia

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