effects on brain development of prenatal inhibition of kynurenine-3-monooxygenase

Glasgow Theses Service http://theses.gla.ac.uk/ theses@gla.ac.uk Khalil, Omari S (2014) Effects on brain development of prenatal inhibition of Kynurenine-3-Monooxygenase. PhD thesis. http://theses.gla.ac.uk/5075/ Copyright and moral rights for this thesis are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given 1 Effects on Brain Development of Prenatal Inhibition of Kynurenine-3-Monooxygenase In the partial fulfilment of the requirements for the degree of Doctor of Philosophy. Institute of Neuroscience and Psychology College of Medical, Veterinary and Life Science University of Glasgow March 2014 © Omari S Khalil BSc (Hons) 2 Much is known about the disease pathology related to schizophrenia, however, little is known with regards to its aetiology. Recent evidences suggest a neurodevelopmental hypothesis for schizophrenia where environmental factors including: infection, stress and malnutrition, can adversely affect the pregnant mother thereby elevating the risk for schizophrenia developing in the offspring during adulthood (Meyer et al., 2008d; Meyer and Feldon, 2009; 2012; Forrest et al., 2012; Meyer, 2013). Since a variety of viral and bacterial infections in animal models have demonstrated to increase the risk in schizophrenia, it is proposed that factors common to the immune response may mediate this link. While many laboratories have reported several behavioural abnormalities following maternal immune activation, we sought to examine molecular changes following poly(I:C) exposure, a synthetic viral mimetic, in the pregnant mother and assessed a range of protein markers with known developmental roles, since an appreciable understanding of the molecular alterations taking place would permit suitable therapies to follow. Interestingly, poly(I:C) was able to induce a range of changes resembling those observed during schizophrenia, where the major NMDA receptor subunit GluN1 and α-Synuclein was reduced in postnatal day 21 animals born to mothers treated with poly(I:C) during gestation days 14, 16 and 18. Furthermore, these changes suggest a mechanism by which maternal immune activation may lead to the subsequent emergence of schizophrenia. Another aspect of this work examined the role of the kynurenine pathway on brain development. There is increasing evidence suggesting the involvement of the kynurenine pathway, a biochemical pathway responsible for the oxidative metabolism of tryptophan, in the disease pathology of schizophrenia, including neurodegenerative disorders such as Parkinson’s, Alzheimer’s and Huntington’s disease (Giorgini et al., 2005; Ting et al., 2009; Bonda et al., 2010). Since immune activation induces the activation of the kynurenine pathway, it was hypothesised that alterations in central kynurenine concentrations during development may be involved in mediating the subsequent increased risk for schizophrenia (Forrest et al., 2013, Khalil et al., 2013, 2014). As very little is known about the physiological activity of the kynurenine pathway during development, we sought to examine the potential consequence of disrupting this pathway and examining its effects upon brain development. Therefore, a kynurenine monooxygenase inhibitor, Ro61-8048, was administered to pregnant rats during gestation day 14, 16, and 18, that would inhibit the synthesis of the neurotoxic metabolite quinolinic acid, while redirecting the pathway to increase the neuroprotectant Abstract 3 kynurenic acid. Brain development was assessed by examining changes in protein expression of markers intimately involved in synaptic transmitter release machinery, neurogenesis and many aspects of neuronal development. Interestingly, we found the kynurenine pathway is highly active during brain development, and induces a variety of changes in protein markers that may be involved in precipitating a range of neuronal and cognitive deficits. While Ro61- 8048 induced no changes in the embryo brains at 5 and 24 h following treatment, delayed changes were seen in postnatal day 21 animals displaying a decrease in RhoB expression as examined in the western blots. Since the full blow symptoms of schizophrenia become apparent during early adulthood, we sought to examine any changes in protein expression in postnatal day 60 animals in regions of the cortex, hippocampus, midbrain and cerebellum. Interestingly, profound alterations were seen in doublecortin and the netrin receptors responsible for axonal guidance. Perhaps the most striking protein change in the postnatal day 60 animals is the significant alteration induced in the expression of disrupted in schizophrenia (DISC)-1, a protein strongly linked with schizophrenia. Glutamate function was assessed as indicated by the density of glutamate transporters, VGLUT-1 and VGLUT-2, in the CA1 region of the hippocampus of postnatal day 60 animals using immunocytochemistry. While the relative density of glutamate transporters were substantially increased, there were no changes in the GABA transporters, indicating that while GABA transmission remained the same, glutamate function may have increased in the absence of an increase in synaptic connections. Spine densities of pyramidal neurons in the hippocampus were also examined, using the golgi-impregnation method, to reveal a significant loss in spines of the apical and basal dendrites, consistent with reports in schizophrenia. To conclude, the kynurenine pathway is highly active during development, and alterations in central kynurenines during pregnancy, as induced by environmental factors such as stress and infection, may be involved in the subsequent emergence of neurodevelopmental disorders. 4 C o n t e n t s P a g e EFFECTS ON BRAIN DEVELOPMENT OF PRENATAL INHIBITION OF KYNURENINE-3-MONOOXYGENASE…………………………………… …… Abstract……………………………………… …………………………………… …. List of Tables List of Figures…………………………………………………………………… …… Acknowledgments…………………………………………………… ………… …… Authors Declaration…………………………………………………….…………… List of Publications…………………………………………………………………… List of Abbreviations………………………………………………………… ……… C H A P T E R O n e : I n t r o d u c t i o n …………………………… . . … PART One……………………………………………………………………………… 1.1 Normal Foetal Development……………….……………… ………………………. 1.2 Abnormal Foetal Development……………………………………………………… 1.2.1 Maternal Influenza Exposure Increases the Risk for Schizophrenia……………….… 1.2.2 Immune Activation Precipitates Developmental Disorders………………………… 1.2.3 Neuroinflammation and Parkinson’s Disease……………………… … 1.3 Immunological Contributors: Cytokines…………………………………… …… … 1.3.1 Cytokine Specific Actions and Dependencies…………………………………… 1.3.2 Candidates for Acute Cytokine Mediators…………………………………….…. 1.4 Interplay of a Heterogeneous Aetiology for Schizophrenia……………………………. 1.5 Experimental Models of Maternal Infection……………………………………… … 1.5.1 Lipopolysaccharide (LPS)…………………………………………….……… 1.5.2 polyriboinosinic-polyribocytidilic acid (Poly(I:C))………………………………… 1.5.2.1 Reason for Selecting poly(I:C) over LPS……………………………… 1.5.3 Timing of Infection and Window of Maximal Foetal Damage………………… … 1.6 Effects of Anti-psychotic Drugs in Immune Challenged Offspring…………… …… 1.6.1 The Kynurenine Pathway : A Missing Link to Developmental Disorders? PART Two…………………………………………………… …………………… … 1.7 The Kynurenine Pathway……………………………….……………………………. 1.7.1 Immune Activation Induces IDO Expression……………………………………. 1.7.1.1 QUIN-Induced Damage in HIV and AIDS-Dementia Complex……… 1.7.1.2 QUIN-Induced Damage in Huntington’s Disease………………………. 1.7.1.3 QUIN-induced Damage in Alzheimer’s Disease…………………… …. 1.7.1.4 Cognitive Decline Associated with Degenerative Disorders……………… 1.7.1.5 Mechanisms of Damage by Quniolinic Acid (QUIN)……………………. 1.8 Drug Development and the Kynurenine Pathway……………………………….……. 1.8.1 Kynurenic Acid (KYNA) Analogues…………………………………… …… 1.8.2 Kynurenic Acid (KYNA) Prodrugs…………………………………… …… … 1.8.3 Indoleamine 2,3-Dioxygenase (IDO) Inhibition…………………………… …… 1.8.4 Kynurenine Monooxygenase (KMO) Inhibition………………………………… 1.8.4.1 Kynurenine Monooxygenase (KMO) Inhibition: ‘Proof of Concept’… …… 1.8.4.2 Kynurenine Monooxygenase (KMO) Inhibitor Ro61-8048………… … 1.8.4.3 KMO Inhibition by Ro61-8048 in Parkinson’s Disease…………….…… 1.8.4.4 Benefit of KMO Inhibition Over NMDA Receptor Blockers……… …… 1.9 Purpose of Study…………………………………………………………… ……… 01 02 08 09 11 12 13 14 16 16 16 16 17 18 19 20 20 21 23 24 25 25 26 26 27 29 31 31 35 36 38 40 40 41 41 41 42 42 42 44 44 45 46 47 5 Aims of the Project……………………………………………………………… ……. C H A P T E R T w o : M e t h o d s ……………………………… . . …… 2.0 Animals……………………………………………………………………… … …… 2.1 Poly(I:C) Injection Schedules…………………………………………………………. 2.1.1 Selected Dosage………………………………………………………………… 2.1.2 Embryo Experiments: 5 h Post Injection………………………………… …… 2.1.3 Neonatal Experiments: Postnatal Day 21 Animals……………………………… 2.2 Ro61-8048 Injection Schedule……………………………………… ….…… …… 2.2.1 Selected Dosage…………………………………………………………….…… 2.2.2 Embryo Experiment: 5 h Post Injection………………………………… ….…… 2.2.3 Embryo Experiments: 24 h Post Injection………………………………………… 2.2.4 Neonatal Experiments: Postnatal Day 21 Animals…………………………….…. 2.2.5 Neonatal Experiments: Postnatal Day 60 Animals……………………………… 2.3 Control Animals……………………………………………………………….… … 2.4 Preparation of Drugs for Animal Injections………………………………… ……… 2.4.1 0.9 % Saline………………………………………………………………… 2.4.2 10 mg/kg poly(I:C)……………………………………………………… … 2.4.3 100 mg/kg Ro61-8048……………………………………………………… 2.5 Experimental Protocol……………………………………………………………… 2.5.1 Western Blots…………………………………………………………………. 2.5.1.1 Injection Schedule…………………………………………… …… 2.5.2 Methods………………………………………………………………………. 2.5.2.1 Sample Preparation………………………………………….… …… 2.5.2.2 Bradford Protein Assay……………………………………………… 2.5.2.3 Gel Electrophoresis………………………………………………… … 2.5.2.4 Gel Transfer…………………………………………….…………… 2.5.2.5 Penceu Staining……………………………………………….…… 2.5.2.6 Antibody Incubation…………………………………….…….…… 2.5.2.7 Antibody Optimisation………………………………………….…… 2.5.2.8 Chemiluminescence…………………………………………………… 2.5.2.9 Data Analysis and Statistics…………………………… ………… … 2.5.3 Immunocytochemistry………………………………………………………… 2.5.3.1 Injection Schedule and Perfusions………………………………………. 2.5.3.2 Methods………………………………………………….……….… 2.5.3.3 Preparation of Buffers………………………………………… … … 2.5.3.4 Confocal Microscopy and Image Acquisition……………………………. 2.5.3.5 Statistical Analysis………………………………………… …… 2.5.4 Golgi Staining………………………………………………………… …… 2.5.4.1 Injection Schedule………………………………………………….… 2.5.4.2 Methods……………………………………………………….… … 2.5.4.2.1 Method of Coating Glass Slides with Gelatin……… … 2.5.4.3 Microscopy…………………………………………………… ……. 2.5.4.4 Statistical Analysis…………………………………………….…… 2.6 Parallel Studies……………………………………………………………….…… … C H A P T E R T h r e e : R e s u l t s ………………………………….… Part One…………………………………………………………….…………………… Poly(I:C) Data: Western Blotting……………………………………………….……… 49 50 50 50 50 51 51 52 52 52 52 52 53 54 54 54 54 54 55 55 55 55 55 55 56 57 57 58 59 59 60 60 60 60 61 62 62 63 63 63 63 64 64 64 66 66 66 6 3.1 Prenatal exposure to poly(I:C) in a rat model of maternal infection induces significant alterations in neurodevelopmental proteins widely associated with the emergence of schizophrenia symptoms…………………………………………………………… …… 3.1.1 Prenatal exposure to poly(I:C) in a rat model of maternal infection does not alter protein expression of markers in embryos at 5 h… …………………………………………… 3.2. Examination of Protein Markers in P21 Animals…………………………… ….… 3.2.1 Prenatal exposure to poly(I:C) in a rat model of maternal infection alters the expression of proteins relevant to schizophrenia in P21 neonatal brains………………………… …… Part Two………………………………………….……………………………………… Ro61-8048 Data: Western Blotting………………… ………………………………… 3.3 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats induces significant delayed alterations of neurodevelopmental proteins in postnatal animals, associated with axonal guidance, neurogenesis and schizophrenia………………………………………………… 3.3.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats does not alter the expression of the selected proteins in the embryo brains at 5 h………………………………….….… 3.4 Examination of Protein Markers in Embryo Brains at 24 h…………………… …… 3.4.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats does not alter the expression of the selected proteins in the embryo brains at 24 h….………………………………… … 3.5 Examination of Protein Markers in P21 Animals……………………………… …… 3.5.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats alters the expression of proteins associated with the function of NMDA receptors in P21brains…….……………… 3.6 Examination of Protein Markers in P60 Animals……………………………….…… 3.6.1 Examination of Protein Markers in the P60 Hippocampus……………… ……… 3.6.1.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats significantly increases the protein expression of doublecortin (DCX) in the hippocampus of postnatal day 60 animals…………………………………………………………………. 3.6.2 Examination of Protein Markers in the P60 Cortex……………………….….… 3.6.2.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats significantly increases the protein expression of DISC-1 in the cortex of postnatal day 60 animals………………………………………………………………… …. 3.6.3 Examination of Protein Markers in the P60 Midbrain……………………….…… 3.6.3.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats induces no changes in protein expression in the midbrain of postnatal day 60 animals…………………. 3.6.4 Examination of Protein Markers in the P60 Cerebellum…………………………. 3.6.4.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats alters the expression of proteins related to axonal guidance in the cerebellum of postnatal day 60 animals……………………………………………………………….……121 Part Three………………………………………………………………………….…… Ro61-8048 Data: Microscopy………………… …………….………………… …… 3.7 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats affects glutamatergic transporters and spine density in the CA1 hippocampus during adulthood…….…………. 3.7.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats increases the density of excitatory transporters in nerve terminals of the stratum pyramidale layer of the hippocampus in postnatal day 60 animals……………………………………………………… … 3.7.2 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats affects hippocampal spine density…………………………………………………………………………. 3.7.2.1 Prenatal inhibition of KMO with Ro61-8048 in pregnant rats reduces spine density of pyramidal cells in the CA1 region of the hippocampus in postnatal day 60 animals………………………………………………………………….…. 66 68 74 75 81 81 81 82 88 89 94 95 101 102 103 108 109 114 115 120 127 127 127 129 135 137 7 C H A P T E R F o u r : D i s c u s s i o n …………… … … . … … … . … . … 1.0 Overview………………………………………………………………………….… 1.1 Poly(I:C) Induced MCP-1 in Maternal Blood………………………………….… … 1.1.1 Changes in Feotal Brain Cytokine Levels Following poly(I:C) Treatment………… … 1.1.2 Direct Action of Virus……………………………………………………….… 1.1.3 Cytokine Actions via Sickness Behaviour…………………………………… … 1.2 Poly(I:C) Failed to Induce Activation of the Kynurenine Pathway……………… … 1.3 Ro61-8048 Does Not Cross the Blood-Brain-Barrier……………………………… 1.3.1 Ro61-8048 Increased Central Kynurenine and Kynurenic Acid……………… … 1.4 Discussion of Results…………………………………………………………… … 1.4.1 Poly(I:C) Decreases GluN1 Expression……………………………………… … 1.4.2 Ro61-8048 Induces no Change in GluN1and PSD-95 Expression…….……….… 1.4.3 DISC-1 Expression Remains Unaffected by poly(I:C) Treatment……………….… 1.4.4 Ro61-8084 Increases DISC-1 Expression in the Cortex of P60 Animals….…… 1.4.5 Poly(I:C) Administration is not Associated with RhoB Activation………… … … 1.4.6 Ro61-8048 Down-Regulates RhoB in Postnatal Day 21 Animals………….…… 1.4.7 Poly(I:C) Induces no Change in the Netrin Proteins……………………… …… 1.4.8 Ro61-8048 Reduces Unc5H3 in the Cerebellum of P60 Animals……………….…. 1.4.9 Prenatal PolyI(:C) Induces no Change in TH Protein Expression………………… 1.4.10 Prenatal Disruption of Kynurenines has no Effect on TH Expression……….……. 1.4.11 Poly(I:C) Induces no Change in the Serotonin (5HT-2 C ) Receptors……………… 1.4.12 Ro61-8048 has no Effect on Serotonin (5HT-2 C ) Receptor Protein Expression….… 1.4.13 α-Synuclein (α-Syn) is Substantially Reduced by poly(I:C)……………………… 1.4.14 Changes in Kynurenines do not Regulate the Activity of α-synuclein………………. 1.4.15 Poly(I:C) does not Affect DCX Protein Expression……………………….…… 1.4.16 Ro61-8048 Administered Prenatally Affects Adult Neurogenesis…………………. 1.4.17 Poly(I:C) has no Effect on the Expression of Synaptic Proteins…………… ….…. 1.4.18 Ro61-8048 Induces no Change in The Expression of Synaptic Proteins….…… … 1.4.19 Ro61-8048 Increases VGLUT Terminals While VGAT Remains Unaffected…… 1.4.20 Ro61-8048 Reduces Hippocampal Spine Density……………………………… 1.5 General Conclusion and Significance of Study…………………………………… 1.5.1 Main Findings – Prenatal Treatment With poly(I:C)……………………………. 1.5.2 Main Findings – Prenatal Treatment With Ro61-8048……………………….…. 1.6 Limitations of the Present Study and Future Work………………………………… C H A P T E R F i v e : R e f e r e n c e s ………… … … … … … . . . … … . . . 140 140 141 142 144 145 146 147 148 149 149 152 154 155 157 159 162 163 163 164 165 168 168 170 171 171 172 173 174 177 182 183 184 186 189 8 Table 2-1. Table of contributions………………………………………………….…… Table 2-2. Table of primary antibodies used in western blotting………………….……… Table 2-3. Table of secondary antibodies used in western blotting…………….….……… Table 2-4. Table of primary antibodies used in immunocytochemistry………… …… … Table 2-5. Table of secondary antibodies used in immunocytochemistry………….……… Table 2-6. The contributions of others referred to ‘in a parallel study’…………………… Table 3-1. Summary of protein changes following poly(I:C) treatment…………………… Table 3-2. Summary of protein changes following Ro61-8048 treatment until P21……… Table 3-3. Summary of protein changes following Ro61-8048 treatment at P60…………. List of Tables 51 58 59 61 61 65 80 126 126 9 Figure 1-1. The oxidative metabolism of tryptophan along the kynurenine pathway.…… Figure 1-2. Simplified diagram of the kynurenine pathway……………………… Figure 1-3. The proposed effect of kynurenine monooxygenase inhibitors……………… Figure 2-1. BSA curve fitting from the Bradford protein assay…………………….… … Figure 3-1. Poy(I:C) increases the expression of MCP-1…………………………………. Figure 3-2. GluN1, DISC-1, RhoA and RhoB expression in poly(I:C)-treated embryo brains……………………………………………………………………………………… Figure 3-3. Unc5H1, Unc5H3 and DCC expression in poly(I:C)-treated embryo brains… Figure 3-4. TH, 5HT-2 C and α-synuclein expression in poly(I:C)-treated embryo brains.… Figure 3-5. VAMP-1 and doublecortin expression in poly(I:C)-treated embryo brains……. Figure 3-6. GluN1, DISC-1, RhoA and RhoB expression in poly(I:C)-treated neonatal brains……………………………………………………………………………………… Figure 3-7. Unc5H1, Unc5H3 and DCC expression in poly(I:C)-treated neonatal brains… Figure 3-8. TH, 5HT-2 C , α-Syn and DCX expression in poly(I:C)-treated neonatal brains Figure 3-9. Expression of synaptic proteins in poly(I:C)-treated neonatal brains… Figure 3-10. Ro61-8048 administered to the pregnant mother induces changes in kynurenines…………………………………………………………………………… …. Figure 3-11. GluN1, DISC-1, RhoA and RhoB expression in Ro61-8048-treated embryo brains……………………………………………………………………………………… Figure 3-12. Unc5H1, Unc5H3 and DCC expression in Ro61-8048-treated embryo brains……………………………………………………………………………………… Figure 3-13. TH, 5HT-2 C and α-synuclein expression in Ro61-8048-treated embryo brains……………………………………………………………………………………… Figure 3-14. VAMP-1 and doublecortin expression in Ro61-8048-treated embryo brains……………………………………………………………………………………… Figure 3-15. GluN1, DISC-1, RhoA and RhoB expression in Ro61-8048-treated embryo brains……………………………………………………………………………………… Figure 3-16. Unc5H1, Unc5H3 and DCC expression in Ro61-8048-treated embryo brains……………………………………………………………………………………… Figure 3-17. TH, 5HT-2 C and α-synuclein expression in Ro61-8048-treated embryo brains……………………………………………… Figure 3-18. VAMP-1 and doublecortin expression in Ro61-8048-treated embryo brains……………………………………………………………………………… … … List of Figures 32 33 43 56 69 70 71 72 73 76 77 78 79 83 84 85 86 87 90 91 92 93 [...]... survival of foetal brain serotonin neurons (Jarskog et al., 1997) Also, IL-1β and IL-6 at low to medium concentrations are equally capable in negatively regulating the survival of foetal midbrain dopaminergic neurons, while at higher concentrations they are able to promote the survival of these cells (Jarskog et al., 1997) Furthermore, low concentrations of TNF-α disrupts the dendritic development of cortical... neurons, while cortical dendritic development can also be disrupted by higher concentrations of IL-1β, IL-6 including TNF-α This demonstrates that cytokine specific reactions occur 21 often with a dependency upon their relative concentration in regulating neuronal populations principally affected in schizophrenia However, not all effects of specific cytokine reactions appear to be solely dependent upon... flattening of the emotional responses, lack of motivation often resulting in social withdrawal, and the onset of auditory and visual hallucinations A strong genetic tendency is observed in familial studies (Harrison and Weinberger, 2005) where twin studies of schizophrenic patients suggest concordance rates of 45% for monozygotic twins and 14% for dizygotic twins (Sullivan et al., 2003) The aetiology of schizophrenia... Introduction Part One Maternal Infection and Developmental Disorders 1.1 Normal Foetal Development The correct neurodevelopment of the central nervous system (CNS) and the normal physiological processes of neurogenesis in the developing foetus is imperative for the normal functioning of mammals The health and well-being of the offspring critically depends upon newly born neurons developing axons that... & Stone, T.W 2013 Prenatal inhibition of the tryptophan–kynurenine pathway alters synaptic plasticity and protein expression in the rat hippocampus Brain Research, 1504, 1-15 *Khalil, O.S., Forrest, C.M., Pisar, M., Smith, R.A., Darlington, L.G., & Stone, T.W 2013 Prenatal activation of maternal TLR3 receptors by viral-mimetic poly(I:C) modifies GluN2B expression in embryos and sonic hedgehog in offspring... risk of schizophrenia developing in the offspring (Brown et al., 2004) Although a variety of studies have shown rodent models of maternal infection exposed to poly(I:C) during early, middle and late stages of gestation are all efficacious in inducing brain abnormalities, one study examining the effects of poly(I:C) exposure on mice during E9 (early/middle gestation) and E17 (late gestation) indicated prenatal. .. mammalian brain, only KAT I and KAT II are widely associated with the transamidation of KYN into KYNA (Guidetti et al., 2007; Yu et al., 2006), while the pharmacological inhibition of KAT II decreases KYNA concentrations (Alkondon et al., 2004) consequently increasing NMDA activity and glutamate release, a mechanism predicted to be useful in treatments of glutaminergic and cholinergic hypofunction like... foetal brain during prenatal infection, however, the precise nature of environment-gene interactions leading to vulnerabilities in developing schizophrenia remains largely unknown It is possible these genes may confer susceptibility to particular disorders or cofound how the developing embryo may react to maternal infection or adverse environments In contrast to rodent models of prenatal infection, the... dependent upon their relative concentration, since studies have shown the effects of developing cells towards cytokines vary as foetal brain development progresses Although TNF-α is neurotrophic in early foetal development towards dopaminergic ventral mesencephalic neurons, during later stages of foetal brain development it precipitates neurotoxic effects to the same neuronal population (Doherty, 2007) In vitro... immunecompromised neuronal networks However, since infections in the second trimester of pregnancy are also efficacious (albeit to a lesser extent) at inducing brain abnormalities, models of maternal infection corresponding to both the first and second trimesters of human pregnancy are of relevance in understanding the pathophysiological alterations occurring in schizophrenia 1.6 Effects of Anti-psychotic . s P a g e EFFECTS ON BRAIN DEVELOPMENT OF PRENATAL INHIBITION OF KYNURENINE-3-MONOOXYGENASE ………………………………… …… Abstract……………………………………… …………………………………… …. List of Tables List of Figures……………………………………………………………………. (IDO) Inhibition ………………………… …… 1.8.4 Kynurenine Monooxygenase (KMO) Inhibition ……………………………… 1.8.4.1 Kynurenine Monooxygenase (KMO) Inhibition: ‘Proof of Concept’… …… 1.8.4.2 Kynurenine Monooxygenase. http://theses.gla.ac.uk/ theses@gla.ac.uk Khalil, Omari S (2014) Effects on brain development of prenatal inhibition of Kynurenine-3-Monooxygenase. PhD thesis. http://theses.gla.ac.uk/5075/