Peter Duncan Neurosciences Research Unit

Sydney, Australia

Peter Duncan Neurosciences Research Unit

Sydney, Australia

Time filter

Source Type

Jones S.P.,Peter Duncan Neurosciences Research Unit | Jones S.P.,University of New South Wales | Franco N.F.,Peter Duncan Neurosciences Research Unit | Varney B.,Peter Duncan Neurosciences Research Unit | And 10 more authors.
PLoS ONE | Year: 2015

The kynurenine pathway is a fundamental mechanism of immunosuppression and peripheral tolerance. It is increasingly recognized as playing a major role in the pathogenesis of a wide variety of inflammatory, neurodegenerative and malignant disorders. However, the temporal dynamics of kynurenine pathway activation and metabolite production in human immune cells is currently unknown. Here we report the novel use of flow cytometry, combined with ultra high-performance liquid chromatography and gas chromatography-mass spectrometry, to sensitively quantify the intracellular expression of three key kynurenine pathway enzymes and the main kynurenine pathway metabolites in a time-course study. This is the first study to show that up-regulation of indoleamine 2,3-dioxygenase (IDO-1), kynurenine 3-monoxygenase (KMO) and quinolinate phosphoribosyltransferase (QPRT) is lacking in lymphocytes treated with interferon gamma. In contrast, peripheral monocytes showed a significant elevation of kynurenine pathway enzymes and metabolites when treated with interferon gamma. Expression of IDO-1, KMO and QPRT correlated significantly with activation of the kynurenine pathway (kynurenine:tryptophan ratio), quinolinic acid concentration and production of the monocyte derived, pro-inflammatory immune response marker: neopterin. Our results also describe an original and sensitive methodological approach to quantify kynurenine pathway enzyme expression in cells. This has revealed further insights into the potential role of these enzymes in disease processes. © 2015 Jones et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Puccetti P.,University of Perugia | Fallarino F.,University of Perugia | Italiano A.,Institute Bergonie | Soubeyran I.,Institute Bergonie | And 12 more authors.
PLoS ONE | Year: 2015

Tumor immune escape mechanisms are being regarded as suitable targets for tumor therapy. Among these, tryptophan catabolism plays a central role in creating an immunosuppressive environment, leading to tolerance to potentially immunogenic tumor antigens. Tryptophan catabolism is initiated by either indoleamine 2,3-dioxygenase (IDO-1/-2) or tryptophan 2,3-dioxygenase 2 (TDO2), resulting in biostatic tryptophan starvation and L-kynurenine production, which participates in shaping the dynamic relationship of the host's immune system with tumor cells. Current immunotherapy strategies include blockade of IDO-1/-2 or TDO2, to restore efficient antitumor responses. Patients who might benefit from this approach are currently identified based on expression analyses of IDO-1/-2 or TDO2 in tumor tissue and/or enzymatic activity assessed by kynurenine/tryptophan ratios in the serum. We developed a monoclonal antibody targeting L-kynurenine as an in situ biomarker of IDO-1/-2 or TDO2 activity. Using Tissue Micro Array technology and immunostaining, colorectal and breast cancer patients were phenotyped based on L-kynurenine production. In colorectal cancer L-kynurenine was not unequivocally associated with IDO-1 expression, suggesting that the mere expression of tryptophan catabolic enzymes is not sufficiently informative for optimal immunotherapy. © 2015 Puccetti et al.


Lovelace M.D.,Peter Duncan Neurosciences Research Unit | Lovelace M.D.,University of New South Wales | Varney B.,Peter Duncan Neurosciences Research Unit | Sundaram G.,Peter Duncan Neurosciences Research Unit | And 8 more authors.
Frontiers in Immunology | Year: 2016

The kynurenine pathway (KP) is the major metabolic pathway of the essential amino acid tryptophan (TRP). Stimulation by inflammatory molecules, such as interferon-γ (IFN-γ), is the trigger for induction of the KP, driving a complex cascade of production of both neuroprotective and neurotoxic metabolites, and in turn, regulation of the immune response and responses of brain cells to the KP metabolites. Consequently, substantial evidence has accumulated over the past couple of decades that dysregulation of the KP and the production of neurotoxic metabolites are associated with many neuroinflammatory and neurodegenerative diseases, including Parkinson's disease, AIDS-related dementia, motor neurone disease, schizophrenia, Huntington's disease, and brain cancers. In the past decade, evidence of the link between the KP and multiple sclerosis (MS) has rapidly grown and has implicated the KP in MS pathogenesis. KP enzymes, indoleamine 2,3-dioxygenase (IDO-1) and tryptophan dioxygenase (highest expression in hepatic cells), are the principal enzymes triggering activation of the KP to produce kynurenine from TRP. This is in preference to other routes such as serotonin and melatonin production. In neurological disease, degradation of the blood-brain barrier, even if transient, allows the entry of blood monocytes into the brain parenchyma. Similar to microglia and macrophages, these cells are highly responsive to IFN-γ, which upregulates the expression of enzymes, including IDO-1, producing neurotoxic KP metabolites such as quinolinic acid. These metabolites circulate systemically or are released locally in the brain and can contribute to the excitotoxic death of oligodendrocytes and neurons in neurological disease principally by virtue of their agonist activity at N-methyl-d-aspartic acid receptors. The latest evidence is presented and discussed. The enzymes that control the checkpoints in the KP represent an attractive therapeutic target, and consequently several KP inhibitors are currently in clinical trials for other neurological diseases, and hence may make suitable candidates for MS patients. Underpinning these drug discovery endeavors, in recent years, several advances have been made in how KP metabolites are assayed in various biological fluids, and tremendous advancements have been made in how specimens are imaged to determine disease progression and involvement of various cell types and molecules in MS. © 2016 Lovelace, Varney, Sundaram, Franco, Ng, Pai, Lim, Guillemin and Brew.


PubMed | Macquarie University and Peter Duncan Neurosciences Research Unit
Type: Journal Article | Journal: Neurotoxicity research | Year: 2016

Amyotrophic lateral sclerosis (ALS) is an idiopathic, fatal, neurodegenerative disease of the human motor system. The pathogenesis of ALS is a topic of fascinating speculation and experimentation, with theories revolving around intracellular protein inclusions, mitochondrial structural issues, glutamate excitotoxicity and free radical formation. This review explores the rationale for the involvement of a novel protein, B-cell lymphoma/leukaemia 11b (Bcl11b) in ALS. Bcl11b is a multifunctional zinc finger protein transcription factor. It functions as both a transactivator and genetic suppressor, acting both directly, binding to promoter regions, and indirectly, binding to promoter-bound transcription factors. It has essential roles in the differentiation and growth of various cells in the central nervous system, immune system, integumentary system and cardiovascular system, to the extent that Bcl11b knockout mice are incompatible with extra-uterine life. It also has various roles in pathology including the suppression of latent retroviruses, thymic tumourigenesis and neurodegeneration. In particular its functions in neurodevelopment, viral latency and T-cell development suggest potential roles in ALS pathology.


PubMed | Macquarie University and Peter Duncan Neurosciences Research Unit
Type: Journal Article | Journal: PloS one | Year: 2015

The kynurenine pathway is a fundamental mechanism of immunosuppression and peripheral tolerance. It is increasingly recognized as playing a major role in the pathogenesis of a wide variety of inflammatory, neurodegenerative and malignant disorders. However, the temporal dynamics of kynurenine pathway activation and metabolite production in human immune cells is currently unknown. Here we report the novel use of flow cytometry, combined with ultra high-performance liquid chromatography and gas chromatography-mass spectrometry, to sensitively quantify the intracellular expression of three key kynurenine pathway enzymes and the main kynurenine pathway metabolites in a time-course study. This is the first study to show that up-regulation of indoleamine 2,3-dioxygenase (IDO-1), kynurenine 3-monoxygenase (KMO) and quinolinate phosphoribosyltransferase (QPRT) is lacking in lymphocytes treated with interferon gamma. In contrast, peripheral monocytes showed a significant elevation of kynurenine pathway enzymes and metabolites when treated with interferon gamma. Expression of IDO-1, KMO and QPRT correlated significantly with activation of the kynurenine pathway (kynurenine:tryptophan ratio), quinolinic acid concentration and production of the monocyte derived, pro-inflammatory immune response marker: neopterin. Our results also describe an original and sensitive methodological approach to quantify kynurenine pathway enzyme expression in cells. This has revealed further insights into the potential role of these enzymes in disease processes.


PubMed | Macquarie University, University of Liverpool, Peter Duncan Neurosciences Research Unit and Xavier University School of Medicine
Type: Review | Journal: Neuropharmacology | Year: 2016

The kynurenine pathway (KP) of tryptophan metabolism has emerged in recent years as a key regulator of the production of both neuroprotective (e.g. kynurenic and picolinic acid, and the essential cofactor NAD+) and neurotoxic metabolites (e.g. quinolinic acid, 3-hydroxykynurenine). The balance between the production of the two types of metabolites is controlled by key rate-limiting enzymes such as indoleamine-2,3-dioxygenase (IDO-1), and in turn, molecular signals such as interferon- (IFN-), which activate the KP metabolism of tryptophan by this enzyme, as opposed to alternative pathways for serotonin and melatonin production. Dysregulated KP metabolism has been strongly associated with neurological diseases in recent years, and is the subject of increasing efforts to understand how the metabolites are causative of disease pathology. Concurrent with these endeavours are drug development initiatives to use inhibitors to block certain enzymes in the pathway, resulting in reduced levels of neurotoxic metabolites (e.g. quinolinic acid, an excitotoxin and N-Methyl-d-Aspartate (NMDA) receptor agonist), while in turn enhancing the bioavailability of the neuroprotective metabolites such as kynurenic acid. Neurodegenerative diseases often have a substantial autoimmune or inflammatory component; hence a greater understanding of how KP metabolites influence the inflammatory cascade is required. Additionally, challenges exist in diseases like multiple sclerosis (MS) and motor neurone disease (MND), which do not have reliable biomarkers. Clinical diagnosis can often be prolonged in order to exclude other diseases, and often diagnosis occurs at an advanced state of disease pathology, which does not allow a lengthy time for patient assessment and intervention therapies. This review considers the current evidence for involvement of the KP in several neurological diseases, in biomarkers of disease and also the parallels that exist in KP metabolism with what is known in other diseases such as HIV, Alzheimers disease/dementia, infection, immune privilege and cardiovascular disease. This article is part of the Special Issue entitled The Kynurenine Pathway in Health and Disease.


PubMed | Monash University, Macquarie University, Peter Duncan Neurosciences Research Unit, Hospital Queen Elizabeth and 3 more.
Type: | Journal: Journal of neuroinflammation | Year: 2015

During inflammation, the kynurenine pathway (KP) metabolises the essential amino acid tryptophan (TRP) potentially contributing to excitotoxicity via the release of quinolinic acid (QUIN) and 3-hydroxykynurenine (3HK). Despite the importance of excitotoxicity in the development of secondary brain damage, investigations on the KP in TBI are scarce. In this study, we comprehensively characterised changes in KP activation by measuring numerous metabolites in cerebrospinal fluid (CSF) from TBI patients and assessing the expression of key KP enzymes in brain tissue from TBI victims. Acute QUIN levels were further correlated with outcome scores to explore its prognostic value in TBI recovery.Twenty-eight patients with severe TBI (GCS 8, three patients had initial GCS = 9-10, but rapidly deteriorated to 8) were recruited. CSF was collected from admission to day 5 post-injury. TRP, kynurenine (KYN), kynurenic acid (KYNA), QUIN, anthranilic acid (AA) and 3-hydroxyanthranilic acid (3HAA) were measured in CSF. The Glasgow Outcome Scale Extended (GOSE) score was assessed at 6 months post-TBI. Post-mortem brains were obtained from the Australian Neurotrauma Tissue and Fluid Bank and used in qPCR for quantitating expression of KP enzymes (indoleamine 2,3-dioxygenase-1 (IDO1), kynurenase (KYNase), kynurenine amino transferase-II (KAT-II), kynurenine 3-monooxygenase (KMO), 3-hydroxyanthranilic acid oxygenase (3HAO) and quinolinic acid phosphoribosyl transferase (QPRTase) and IDO1 immunohistochemistry.In CSF, KYN, KYNA and QUIN were elevated whereas TRP, AA and 3HAA remained unchanged. The ratios of QUIN:KYN, QUIN:KYNA, KYNA:KYN and 3HAA:AA revealed that QUIN levels were significantly higher than KYN and KYNA, supporting increased neurotoxicity. Amplified IDO1 and KYNase mRNA expression was demonstrated on post-mortem brains, and enhanced IDO1 protein coincided with overt tissue damage. QUIN levels in CSF were significantly higher in patients with unfavourable outcome and inversely correlated with GOSE scores.TBI induced a striking activation of the KP pathway with sustained increase of QUIN. The exceeding production of QUIN together with increased IDO1 activation and mRNA expression in brain-injured areas suggests that TBI selectively induces a robust stimulation of the neurotoxic branch of the KP pathway. QUINs detrimental roles are supported by its association to adverse outcome potentially becoming an early prognostic factor post-TBI.


PubMed | University of New South Wales and Peter Duncan Neurosciences Research Unit
Type: | Journal: Journal of neuroinflammation | Year: 2015

The excitotoxin quinolinic acid, a by-product of the kynurenine pathway, is known to be involved in several neurological diseases including multiple sclerosis (MS). Quinolinic acid levels are elevated in experimental autoimmune encephalomyelitis rodents, the widely used animal model of MS. Our group has also found pathophysiological concentrations of quinolinic acid in MS patients. This led us to investigate the effect of quinolinic acid on oligodendrocytes; the main cell type targeted by the autoimmune response in MS. We have examined the kynurenine pathway (KP) profile of two oligodendrocyte cell lines and show that these cells have a limited threshold to catabolize exogenous quinolinic acid. We further propose and demonstrate two strategies to limit quinolinic acid gliotoxicity: 1) by neutralizing quinolinic acids effects with anti-quinolinic acid monoclonal antibodies and 2) directly inhibiting quinolinic acid production from activated monocytic cells using specific KP enzyme inhibitors. The outcome of this study provides a new insight into therapeutic strategies for limiting quinolinic acid-induced neurodegeneration, especially in neurological disorders that target oligodendrocytes, such as MS.

Loading Peter Duncan Neurosciences Research Unit collaborators
Loading Peter Duncan Neurosciences Research Unit collaborators