published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

Valproic acid (VPA) is a broad-spectrum anticonvulsant and antiepileptic drug and widely used in many neurological conditions and psychiatric disorders as well as in cancer and HIV treatment. However, despite all its many benefits, VPA also has side effects. It is a strong fetal teratogen that can induce congenital malformation and neurodevelopmental problems. Case reports and population studies have revealed that prenatal exposure to VPA is associated with a higher risk of autism in postnatal life. Animal models also have confirmed that VPA can induce autistic-like features in rodents. Yet, there are some questions remaining unanswered by existing animal studies of prenatal VPA exposure. The embryotoxicity of a drug is not only determined by its own chemical, physiological or pharmacological properties, but also on the dose and the time in development that the exposure happens. The majority of studies investigating the behavioral, neuroanatomical and physiological impact of VPA in animals have examined early gestational exposure to relatively high doses that can cause significant malformation or loss of offspring. Thus, although there are behavioral alterations considered similar to autistic symptoms in humans, these are found in the offspring that have survived a very toxic insult, leading to problems of interpretation. Low dose exposure has not been widely studied, nor has the impact of VPA exposure late in gestation. Moreover, how the age and sex of offspring influences the phenotypic outcome has rarely been considered. Therefore, in the present series of studies, a battery of behavioral tests and in vivo magnetic resonance imaging (MRI) was used to investigate the postnatal consequences of prenatal exposure to lower doses of VPA in mice in early and late gestation. The effects of VPA were examined in female and male mice at juvenile and adult ages. The main findings were, that low doses of VPA in early or late gestation cause no physical malformation and no gross neurological functional impairments, but induce behavioral abnormalities and neuroanatomical differences related to autism. Generally, VPA-treated mice exhibited lower motor activities and higher anxiety levels in the open field test; dislike of novelty in the novel abject exploration test; higher startle response and sensorimotor gating differences; decreased responses to non-social and social odors in the olfactory test; and volumetric changes in brain structures similar to those found in autism. However, the timepoint of exposure, dose of VPA, sex and age of testing influenced the phenotypic outcome. Although largely neglected in previous studies, late gestation exposure to VPA elicited an autistic phenotype. Surprisingly, given the male bias in autism, female mice were often more ‘sensitive’ to VPA. Although the present studies had some limitations, these experiments confirmed that low dose VPA in pregnancy could trigger behavioral abnormalities and brain anatomical differences in mice that resembled a range of features of autism. Importantly, these behaviors were unconfounded by ‘gross’ neurological or physical abnormalities. Further studies to investigate the cellular mechanisms underlying the low dose VPA phenotype will therefore be helpful to shed light on possible causal pathways with specific relevance to autism. / published_or_final_version / Psychiatry / Doctoral / Doctor of Philosophy

Obesity is one of the leading causes of world-wide life-threatening diseases, such as type 2 diabetes mellitus, atherosclerosis and cardiovascular diseases. So far, there is no effective, promising and safe remedy. Development of cost-effective anti-obesity therapies and promising biomarkers for obesity-related diseases have become a demanding task. Lipocalins, such as LCN13, were recently identified as potential drug target because of its beneficial effects on glucose and fat metabolism in mouse. LCN14 is a putative lipocalin that share high degree of homology with LCN13. In this study, it is experimentally proved that LCN14 is a secretory protein that is mainly expressed in white adipose tissues. It is also demonstrated that serum LCN14 level was significantly increased in mice with HFD treatment, and it was significantly reduced in diet-induced obese and diabetic (db/db) mice. In addition, the degree of suppression of circulating LCN14 was greater than that of LCN13 in diet-induced obese and db/db mice. Therefore, serum LCN14 level could be a promising marker for risk prediction of obesity and its complications. Further investigation is urgently needed to unveil the important roles of LCN14 in metabolism. / published_or_final_version / Medicine / Master / Master of Medical Sciences

Stroke is a serious cerebral vascular event and a leading cause of death and disability worldwide, and ischemic stroke is the most common type. Evidence from animal research in acute cerebral ischemia shows that a combination of neuroprotectants might be more efficacious than the single agent given individually. Both melatonin and electro-acupuncture (EA) have been suggested to be effective treatments against cerebral ischemia. However, it is unknown whether a combination of these two therapies could be beneficial against focal cerebral ischemia. In the first study, the effect of post-treatment with a combination of melatonin and EA on regional cerebral blood flow (rCBF), neurological deficit score and infarct volume was investigated in both permanent and transient middle cerebral artery occlusion (MCAO) models in rats. When compared with the single treatment of melatonin or EA, the combination therapy resulted in a significant improvement of neurological function and a dramatic reduction of infarct volume at 72 hr after transient MCAO. A significant upregulatory effect on rCBF has been exerted by the combined treatment. The effect of a combination of melatonin and EA on inflammatory reaction was investigated in the second study. Post-treatment of the combination therapy effectively inhibited neutrophil infiltration as well as the expression of some pro-inflammatory mediators, and increased the anti-inflammatory protein expression at 72 hr after transient MCAO. This beneficial effect may be due to the respective anti-inflammatory effects of melatonin and EA. In the third study, the effect of a combination of melatonin and EA on apoptosis was examined. When compared with the EA treatment alone, post-treatment of the combination therapy exerted a greater inhibitory effect on tissue apoptosis and expression of the pro-apoptotic proteins as well as an upregulatory effect on the anti-apoptotic protein expression. In the fourth study, the effect of continuous post-treatment of a combination of melatonin and EA on transient MCAO was investigated. The combination treatment significantly improved neurological function and decreased infarct volume at 7 days after transient MCAO. Cell proliferation and expression of the neurotrophic factor were increased by the combined treatment. The effect of pretreatment with a combination of melatonin and EA was examined in the fifth study. Neurological function was improved and infarct volume was reduced by the combination pretreatment at 24 hr after transient MCAO. The inflammatory and apoptotic reaction were inhibited by the combined pretreatment through the modulatory effect of the related proteins. In summary, our results show that, when compared with the single treatment of either melatonin or EA, post-treatment with a combination of melatonin and EA induced a complementary neuroprotective effect on improvement of neurological function and a dramatic reduction of infarct volume after transient MCAO. The complementary protection may be partially mediated via anti-inflammation and anti-apoptosis after transient cerebral ischemia. Pretreatment with a combination of melatonin and EA may be more effective in preventing ischemic brain injury after transient focal cerebral ischemia. / published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that is characterized by auto-reactive T and B lymphocytes and abundant auto-antibodies against nuclear components that form immune-complexes and lead to inflammation, organ dysfunction and failure. The current treatment for SLE includes corticosteroid and immunosuppressant agents which are associated with side effects. Immunotherapy such as tolerogenic dendritic cells (DCs) and regulatory T cells have potential therapeutic implications in autoimmune diseases. DCs are professional antigen presenting cells with important role in promoting immune response and maintaining peripheral tolerance. Alternatively activated DC (aaDC) derived from treating monocyte-derived DCs with vitamin D3 and dexamethasone has demonstrated tolerogenicity and suppressed activation and proliferation of allogeneic T cells in in vitro human studies. As circulating DCs in SLE patients were reported to be hyperactive with increased expression of co-stimulatory molecules and hyper-responsiveness to immunostimulatory stimuli. Therefore, this study aims to examine if aaDCs derived from SLE patients possess tolerogenic properties, to delineate the underlying mechanisms and to examine for therapeutic effect by adoptive transfer of tolerogenic DCs in lupus mouse model. We found that lupus aaDCs derived in vitro displayed semi-mature phenotype with lower expression of co-stimulatory molecules compared with mature DCs. The tolerogenic phenotype remained stable despite challenge by CD40L, CpG-DNA and SLE serum. Lupus aaDCs showed comparable tolerogenic properties as aaDCs from healthy subjects with suppressive effect on allogeneic T cell activation and proliferation. In addition, lupus and normal aaDCs were shown to polarize normal and lupus naïve T cells into IL-10+ suppressive T cells that showed antigen-nonspecific suppressive effect on allogeneic third-party T cells. On the other hand, lupus and normal aaDCs skewed memory T cells to less inflammatory phenotype with reduced expression of IFN-ɤ and IL-17. Although aaDCs displayed a cytokine profile of IL-12loIL-10hi, addition of neutralizing anti-IL-10 and exogenous IL-12 did not reverse the suppressive effect of aaDCs on allogeneic T cells, suggesting their tolerogenicity was not related to cytokine imbalance between IL-12 and IL-10. Furthermore, aaDCs were found to express reduced level of RelB, a transcription factor regulating DC differentiation and maturation. As RelB can be a potential target to induce stable tolerogenic DCs, we constructed RelB shRNA to silence RelB in bone marrow derived DCs (BMDCs) from MRL/MPJ mice. The RelB shRNA transduced BMDCs showed lower level of RelB compared with scramble control shRNA, and displayed tolerogenic phenotype with decreased co-stimulatory molecules, but had no effect on the expression of chemokine receptors. When co-cultured with allogenic CD4+ T cells, RelB shRNA modified BMDCs showed suppressive function on T cell activation and proliferation and increased the production of IL-10 by T cells. However, in vivo study based on 5 mice per treatment group did not show significant effect of RelB shRNA modified BMDCs on disease progress of lupus mice compared to control mice. In conclusion, lupus aaDCs demonstrated tolerogenic properties with induction of IL-10 producing T cells with regulatory functions. RelB shRNA modified BMDCs showed tolerogenic properties in vitro but their in vivo effect on alleviation of murine lupus disease needs further study. / published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

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