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No description available.

No description available.

No description available.

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 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.

Research investigating the regulation of muscle fibre type has traditionally been conducted in vivo, analyzing global changes at a whole muscle level. Broadly, this thesis aimed to explore more “molecular” approaches, utilizing molecular and cell biology to understand the expression and regulation of myosin heavy chain (MyHC) isoforms as an indicator of muscle fibre composition. The mRNA expression profile of six MyHC isoform genes during C2C12 myogenesis was elucidated to reveal that the C2C12 cell line mimics developing fast-twitch muscle fibres. Additional characterization of the C2C12 cell line revealed a dramatic restructuring of metabolic gene expression during the switch from proliferating to fully differentiated C2C12 muscle cells. Post-mitotic muscle cells exhibited increased glycolytic gene expression and reduced oxidative gene expression and an increase in gene expression of enzymes involved in redirecting glucose carbons into ATP generating pathways and away from macromolecule biosynthesis (p<0.01 for all genes). The dynamic plasticity of MyHC isoform gene expression was compared between C2C12 muscle cells and fully differentiated adult muscle. Exposure of adult muscle to the beta-adrenergic agonist, Ractopamine, induced dynamic transitions in MyHC isoform expression, from the IIA/IIX isoforms to increased IIB isoform expression (p<0.05 for all genes). An acute exposure of C2C12 muscle cells to Ractopamine was capable of inducing an exclusive and rapid induction of the MyHC IIB isoform gene expression during myogenesis (p<0.001). The C2C12 cell line was utilized as a host environment for a molecular-based approach to understand the role of the promoter sequence in regulating the species-differential induction of the MyHC IIB gene during myogenesis. A 3bp miss-match in the CArG-Ebox region (at -74bp, -68bp and -48bp) of the proximal MyHC IIB promoter was identified that dictates the differential expression of MyHC IIB in pigs and humans.

Phosphoinositides are lipid signals that control cellular processes and are particularly closely associated with the control of membrane trafficking. PtdIns(3,5) \(\char{cmmi10}{0x50}\)\(_2\) is the most recently identified phosphoinositide and was previously recognised as controlling events in the late endocytic system between the late endosome and the vacuole/lysosome. Primarily associated with retrograde trafficking from the vacuole/lysosome to the late endosome/MVB, PtdIns(3,5) \(\char{cmmi10}{0x50}\)\(_2\) is generated by the kinase Fab1p (PIKfyve in animals). In mammalian cells, PtdIns(3,5) \(\char{cmmi10}{0x50}\)\(_2\) has also been implicated in control of ill-defined trafficking pathways close to the Golgi; for example, the recycling of mannose-6-phosphate receptor (M6R) back to the Golgi and also the trafficking of some types of ion and nutrient channels from the Golgi to the cell surface. This thesis describes attempts to study putative PtdIns(3,5) \(\char{cmmi10}{0x50}\)\(_2\) dependent trafficking in the early endocytic system of \(\char{cmmi10}{0x53}\). \(\char{cmmi10}{0x63}\)\(\char{cmmi10}{0x65}\)\(\char{cmmi10}{0x72}\)\(\char{cmmi10}{0x65}\)\(\char{cmmi10}{0x76}\)\(\char{cmmi10}{0x69}\)\(\char{cmmi10}{0x73}\)\(\char{cmmi10}{0x69}\)\(\char{cmmi10}{0x61}\)\(\char{cmmi10}{0x65}\) using two model proteins; the recycling of Vps10p from late endosome to Golgi and of Chs3p from recycling endosome to Golgi.

Musculoskeletal disorders are among the most important health problem affecting the quality of life and contributing to a high burden on healthcare systems worldwide. Understanding the molecular mechanisms underlying these disorders is crucial for the development of efficient treatments. In this thesis, musculoskeletal disorders including muscle wasting, bone loss and cartilage deformation have been studied using systems biology approaches. Muscle wasting occurring as a systemic effect in COPD patients has been investigated with an integrative network inference approach. This work has lead to a model describing the relationship between muscle molecular and physiological response to training and systemic inflammatory mediators. This model has shown for the first time that oxygen dependent changes in the expression of epigenetic modifiers and not chronic inflammation may be causally linked to muscle dysfunction. Bone and cartilage deformation observed in ageing, arthritis and multiple myeloma (MM) patients have also been investigated by using a novel modularization approach developed within this thesis. This methodology allows integration of multi-level dataset with large interaction networks. It aims to identify sub-networks with genes differentially expressed between experimental conditions that are co-regulated across samples in different biological systems. This study has identified several potential key players such as Myc, DUSP6 and components of Notch that could enhance osteogenic differentiation in MM patients. In conclusion, this thesis present the effectiveness of systems biology approaches in understanding complex diseases and these approaches could be applied for studying other systems and datasets.

A third of over 65s have at least one fall per year whilst a quarter of over 45s endure foot pain. Footwear is associated with both fall risk and foot pain hence its investigation is of great importance. This thesis explores the potential benefits of minimalist footwear for the older adult population. Chapter 2 ascertained the kinematic and kinetic differences between walking barefoot versus in footwear whilst highlighting the limited research on minimalist footwear, older adults and muscle activity differences. Accordingly, Chapter 3 outlined that minimalist footwear is kinematically more similar to barefoot, irrespective of age, thus offering a viable alternative. Similarly, Chapter 4 showed walking in minimalist footwear and walking unshod exhibit similar lower leg muscle activation patterns whilst differences exist to conventional footwear. Chapter 6 demonstrated how increasing intrinsic foot strength improved functional and static balance whilst Chapter 7 showed promise for minimalist footwear improving foot strength, functional balance, balance confidence as well as reducing foot and joint pain in a sample of older adults. In conclusion, this thesis highlights the need for future work to continue to investigate minimalist footwear in both older adults and other age groups for benefits to stability, foot health and joint pain.

Symptoms of gastro-oesophageal reflux disease are equally common in both sexes and at all ages. However, complications of gastro-oesophageal reflux disease such as reflux oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma, although more common in men, increase sharply in older women, suggestive of a protective effect of female sex hormones in menstruating women. Oestrogen has anti-inflammatory properties, improves healing in oral and skin wounds and may therefore reduce the severity of reflux-induced oesophageal mucosal injury, consequently protecting women from developing severe reflux oesophagitis. Long-term oestrogen treatment with hormone replacement therapy seems to be additionally associated with a reduction in the risk of oesophageal cancer. Moreover, there are gender-specific genotypic differences in the response of oesophageal mucosa to chronic acid reflux suggestive of multiple factors that may play a role in explaining the male predominance of oesophageal adenocarcinoma. Finally, oestrogen has no association with the severity of acid reflux once adjustment is made for the influence of increasing body mass index in women undergoing oesophageal pH monitoring. The gender difference in the prevalence of gastro-oesophageal reflux disease and its complications may thus be related to the effect of female sex hormones, particularly oestrogen and its 'protective' effect in pre-menopausal women.