Frontotemporal lobar degeneration (FTLD) is an early onset neurodegenerative disorder which selectively destroys frontal and temporal cortical neurones. The resulting damage leads to a range of language and behavioural deficits, however, episodic memory is generally maintained. Around 10% of FTLD cases are caused by progranulin gene mutations that lead to haploinsufficiency and reduced expression of progranulin. Secretory leukocyte protease inhibitor (SLPI) has been shown to have a key protective effect over progranulin, inhibiting enzymatic cleavage by neutrophil elastase. Previous work demonstrating this role of SLPI is largely from in vitro studies and scenarios with above-physiological SLPI concentrations. To ascertain a role for endogenous SLPI in the regulation of progranulin a murine SLPI knockout model was used and tonic progranulin measurements taken. No change in circulating progranulin levels were seen in SLPI null mice (at 6, 12 or 20 months of age) when compared to non-transgenic controls, though significant differences were observed between male and female SLPI null animals. Similarly, tissue (brain and lung) levels of progranulin were comparable between wild-type and SLPI null mice, despite the presence of active neutrophil elastase. Behavioural analysis of SLPI null mice revealed no major phenotype when compared to wild-type, over a range of behavioural tests. However primary neuronal cultures taken from SLPI null mice did display an elevated progranulin response to bacterial lipopolysaccharide (LPS). These data suggest that, although SLPI may play a role in progranulin regulation during an inflammatory event, it is unlikely to play a major role in progranulin regulation under basal conditions, as reported previously. Therefore under disease conditions regulation of extracellular progranulin is likely through other modulatory factors that have yet to be described.

The majority of the estimated three million traumatic brain injuries that occur each year are classified as “mild” and do not require surgical intervention. However, debilitating symptoms such as difficulties focusing on tasks, anxiety, depression, and visual deficits can persist chronically after a mild traumatic brain injury (TBI) even if an individual appears “fine”. These symptoms have been observed to worsen or be prolonged when an individual has suffered multiple mild TBIs. To test the hypothesis that increasing the amount of time between head injuries can reduce the histopathological and behavioral consequences of repeated mild TBI, a mouse model of closed head injury (CHI) was developed. A pneumatically controlled device with a silicone tip was used to deliver a diffuse, midline impact directly onto the mouse skull. A 2.0mm intended depth of injury caused a brief period of apnea and increased righting reflex response with minimal astrogliosis and axonal injury bilaterally in the entorhinal cortex, optic tract, and cerebellum. When five CHIs were repeated at 24h inter-injury intervals, astrogliosis was exacerbated acutely in the hippocampus and entorhinal cortex compared to a single mild TBI. Additionally, in the entorhinal cortex, hemorrhagic lesions developed along with increased neurodegeneration and microgliosis. Axonal injury was observed bilaterally in the white matter tracts of the cerebellum and brainstem. When the inter-injury interval was extended to 48h, the extent of inflammation and cell death was similar to that caused by a single CHI suggesting that, in our mouse model, extending the inter-injury interval from 24h to 48h reduced the acute effects of repeated head injuries. The behavioral consequences of repeated CHI at 24h or 48h inter-injury intervals were evaluated in a ten week longitudinal study followed by histological analyses. Five CHI repeated at 24h inter-injury intervals produced motor and cognitive deficits that persisted throughout the ten week study period. Based upon histological analyses, the acute inflammation, axonal injury, and cell death observed acutely in the entorhinal cortex had resolved by ten weeks after injury. However, axonal degeneration and gliosis were present in the optic tract, optic nerve, and corticospinal tract. Extending the inter-injury interval to 48h did not significantly reduce motor and cognitive deficits, nor did it protect against chronic microgliosis and neurodegeneration in the visual pathway. Together these data suggested that some white matter areas may be more susceptible to our model of repeated mild TBI causing persistent neuropathology and behavioral deficits which were not substantially reduced with a 48h inter-injury interval. In many forms of TBI, microgliosis persists chronically and is believed to contribute to the cascade of neurodegeneration. To test the hypothesis that post-traumatic microgliosis contributes to mild TBI-related neuropathology, mice deficient in the growth factor progranulin (Grn-/-) received repeated CHI and were compared to wildtype, C57BL/6 mice. Penetrating head injury was previously reported to amplify the acute microglial response in Grn-/- mice. In our studies, repeated CHI induced an increased microglial response in Grn-/- mice compared to C57BL/6 mice at 48h, 7d, and 7mo after injury. However, no differences were observed between Grn-/- and WT mice with respect to their behavioral responses or amount of axonal injury or ongoing neurodegeneration at 7 months despite the robust differences in microgliosis. Dietary administration of ibuprofen initiated after the first injury reduced microglial activation within the optic tract of WT mice 7d after repeated mild TBI. However, a two week ibuprofen treatment regimen failed to affect the extent of behavioral dysfunction over 7mo or decrease chronic neurodegeneration, axon loss, or microgliosis in brain-injured Grn-.- mice when compared to standard diet. Together these studies underscore that mild TBIs, when repeated, can result in long lasting behavioral deficits accompanied by neurodegeneration within vulnerable brain regions. Our studies on the time interval between repeated head injuries suggest that a 48h inter-injury interval is within the window of mouse brain vulnerability to chronic motor and cognitive dysfunction and white matter injury. Data from our microglia modulation studies suggest that a chronically heightened microglial response following repeated mild TBI in progranulin deficient mice does not worsen chronic behavioral dysfunction or neurodegeneration. In addition, a two week ibuprofen treatment is not effective in reducing the microglial response, chronic behavioral dysfunction, or chronic neurodegeneration in progranulin deficient mice. Our data suggests that microglia are not a favorable target for the treatment of TBI.

The aim of this thesis was to identify genetic factors involved in frontotemporal lobar degeneration (FTLD), a neurodegenerative disorder clinically characterised by a progressive change in personality, behaviour and language. FTLD is a genetically complex disorder and a positive family history is found in up to 40% of the cases. In 10-20% of the familial cases the disease can be explained by mutations in the gene encoding the microtubule associated protein tau (MAPT). In the first study we describe the clinical and neuropathological features of a Finnish family with FTLD caused by a mutation in MAPT. We also provide evidence that the pathogenic mechanism of this mutation is through altered splicing of MAPT transcripts. Recently, mutations in the gene encoding progranulin (PGRN) were identified as a major cause of FTLD. In the second study we describe a Swedish family with FTLD caused by a frameshift mutation in PGRN. We provide a clinical and neuropathological description of the family, as well as evidence that the pathogenicity of this mutation is through nonsense-mediated decay of the mutant mRNA transcripts and PGRN haploinsufficiency. In the third study we describe a novel PGRN splice site mutation and a previously described PGRN frameshift mutation, found in a mutation screen of 51 FTLD patients. We describe the clinical and neuropathological characteristics of the mutation carriers and demonstrate that haploinsufficiency is the pathogenic mechanism of the two mutations. In the fourth study we investigate the prevalence of PGRN and MAPT gene dosage alterations in 39 patients with FTLD. No gene dosage alterations were identified, indicating that variations in copy number of the PGRN and MAPT genes are not a common cause of disease, at least not in this FTLD patient collection.

A cirrose é caracterizada por fibrose e por nódulos regenerativos que resultam na desorganização da arquitetura tecidual, sendo considerado um estágio irreversível. A administração de fatores hepatotróficos exógenos (FHE) poderia estimular a proliferação celular de células hepáticas e reduzir a cirrose induzida em ratos. Deste modo, os FHE atuariam na remodelação da matriz extracelular (ECM). Os objetivos desse trabalho foram avaliar os efeitos dos FHE em ratos cirróticos induzidos experimentalmente por tioacetamida. Foram realizadas análises histopatológicas, imunoistoquímica para BrdU, mensuração de colágeno, microscopia eletrônica de varredura, análises bioquímicas de função hepática e avaliação da expressão gênica de colágeno α1, TGFβ1, TIMP I, MMP 2 e Plau, por PCR em tempo real. Após administração de FHE obteve-se diminuição da expressão gênica dos genes fibrogênicos: colágenoα1, TGFβ1, TIMP I e MMP 2. Durante a remodelação da ECM foram observadas melhoras morfofuncionais, com diminuição do número de nódulos regenerativos parenquimais, diminuição da espessura dos septos fibrosos e reaparecimento de veias centrolobulares. Foi observado aumento do peso e volume do fígado dos ratos, assim como aumento na relação fígado/carcaça. Os animais tratados com FHE apresentaram redução de 29,62% do colágeno parenquimal total, quando comparados com sua própria biópsia antes do tratamento. Animais não submetidos ao tratamento com FHE tiveram um acréscimo de 8,7% de colágeno. Os índices de função hepática revelaram decréscimo significante nos níveis de gamaglutamiltranspeptida (GGT), alanina aminotransferase e aspartato aminotransferase. Desta forma, os FHE atuaram na remodelação da matriz extracelular hepática em fígados cirróticos pela diminuição da expressão de genes fibrogênicos e não necessariamente pelo aumento da expressão de genes fibrolíticos. Ademais, animais cirróticos apresentaram em seu fígado e intestino progranulina, um novo fator de crescimento. Propomos, dessa forma, a utilizalção da progranulina como um possível marcador clínico e alvo terapêutico para doenças hepáticas. / Cirrhosis is characterized by fibrosis and regenerative nodules, which result in the disorganization of the hepatic architecture, being considered an irreversible situation. The administration of exogenous hepatotrophic factors (EHF) could stimulate hepatic regeneration in hepatocytes cells and reduce the cirrhosis induced in rats. The aim of this work was to evaluate the effect of EHF in rat cirrhosis induced experimentally by thioacetamide. It was carried out histopathologics analysis; BrdU imunoperoxidase, collagen measurement, scanning electron microscopy; biochemical analysis for hepatic function and analysis on genic expression for collagen α1, TGFβ 1, TIMP I, MMP 2, and Plau by real time PCR. After the EHF administration, it was observed a reduction in the expression of fibrogenics genes as: collagenα1, TGFβ1, TIMP I and MMP 2. During the extracellular matrix (ECM) remodelation morphofuntional improvements were observed, with decrease of regenerative nodules and fibrous septs thickness as well as reappearance of central vein. It was observed increase in liver weight, volume and in the relation liver/carcass. The animals treated with EHF had a reduction of 29.62% in the total collagen when compared with their own biopsy before treatment, while the non-treated animals had an increase of 8,7%. The index of hepatic functions had significant improvement in the levels of gamaglutamiltranspeptida (GGT), alanine aminotransferase and aspartate aminotransferase. Therefore, the EHF acts on the extracellular matrix remodelation though reduction of fibrogenics gene expression and not necessarily by fibrolitics genes expression increase. In addiction, we have found progranulin, a new growth factor, in liver and intestine of cirrhotic animals. Hence, we propose the utilization of progranulin as a clinical marker and a therapeutic target for hepatic deseases.

The aim of this thesis was to identify genetic factors involved in frontotemporal lobar degeneration (FTLD), a neurodegenerative disorder clinically characterised by a progressive change in personality, behaviour and language. FTLD is a genetically complex disorder and a positive family history is found in up to 40% of the cases. In 10-20% of the familial cases the disease can be explained by mutations in the gene encoding the microtubule associated protein tau (MAPT). In the first study we describe the clinical and neuropathological features of a Finnish family with FTLD caused by a mutation in MAPT. We also provide evidence that the pathogenic mechanism of this mutation is through altered splicing of MAPT transcripts. Recently, mutations in the gene encoding progranulin (PGRN) were identified as a major cause of FTLD. In the second study we describe a Swedish family with FTLD caused by a frameshift mutation in PGRN. We provide a clinical and neuropathological description of the family, as well as evidence that the pathogenicity of this mutation is through nonsense-mediated decay of the mutant mRNA transcripts and PGRN haploinsufficiency. In the third study we describe a novel PGRN splice site mutation and a previously described PGRN frameshift mutation, found in a mutation screen of 51 FTLD patients. We describe the clinical and neuropathological characteristics of the mutation carriers and demonstrate that haploinsufficiency is the pathogenic mechanism of the two mutations. In the fourth study we investigate the prevalence of PGRN and MAPT gene dosage alterations in 39 patients with FTLD. No gene dosage alterations were identified, indicating that variations in copy number of the PGRN and MAPT genes are not a common cause of disease, at least not in this FTLD patient collection.

Corticobasal Syndrome (CBS) is a rare movement and cognitive disorder. There is significant heterogeneity observed in it clinical presentation, neuroimaging, pathology and genetics. Understanding this heterogeneity is a priority and may help to shed light on underlying pathogenic mechanisms. We first demonstrated that truncating mutations in the progranulin gene (PGRN) can cause familial CBS associated with frontotemporal lobar degeneration (FTLD)-ubiquitin pathology. This study identified a mutation in PGRN (Intervening Sequence 7+1 guanine > adenine [IVS7+1G>A]) that segregated with CBS in a family. The mutation was predicted to result in a shortened messenger RNA (mRNA) sequence and the absence of the mutant PGRN allele was confirmed in the reverse transcriptase-polymerase chain reaction (RT-PCR) product, which supported the model of haploinsufficiency for PGRN-linked disease. In a second familial study, clinical, radiological, genetic, and pathological studies were performed to contrast clinical features of the affected members. Sequencing PGRN revealed a novel, heterozygous cytosine-adenine dinucleotide deletion in exon 11 (g.2988_2989delCA, P439_R440fsX6). The proband`s clinical diagnosis was frontotemporal dementia and parkinsonism (FTDP). The proband’s brother with the same mutation presented initially as a progressive non-fluent aphasia (PNFA), and later evolved into a CBS. Pathological analysis revealed Frontotemporal Lobar Degeneration-Ubiquitin (FTLD-U)/ TAR DNA-binding protein 43 (TDP43) positive pathology. The next studies shift away from pathogenic mechanisms to focus on brain-behavioural correlations and phenotypic heterogeneity in a prospective sample of 31 CBS cases. We provide the first direct correlative analysis between the severity of ideomotor apraxia, a common sign in CBS, and cerebral SPECT perfusion imaging. Reductions in perfusion within the left inferior parietal lobule (t=5.7, p=0.03, Family-Wise Error [FWE] corrected), including the left angular gyrus (t=5.7, p=0.02, FWE corrected), were associated with more severe ideomotor apraxia. We stratified the sample into CBS presenting with early motor features (CBS-M; n=9) or early dementia (CBS-D; n=22), which identified that CBS-M were more likely to have cortical sensory loss than CBS-D (p=0.005). In contrast, the presence of aphasia was found to be more common and severe in CBS-D compared to CBS-M (p=0.02). CBS-M patients had significantly reduced perfusion in the right supplementary and premotor areas compared to CBS-D (p<0.05).

Corticobasal Syndrome (CBS) is a rare movement and cognitive disorder. There is significant heterogeneity observed in it clinical presentation, neuroimaging, pathology and genetics. Understanding this heterogeneity is a priority and may help to shed light on underlying pathogenic mechanisms. We first demonstrated that truncating mutations in the progranulin gene (PGRN) can cause familial CBS associated with frontotemporal lobar degeneration (FTLD)-ubiquitin pathology. This study identified a mutation in PGRN (Intervening Sequence 7+1 guanine > adenine [IVS7+1G>A]) that segregated with CBS in a family. The mutation was predicted to result in a shortened messenger RNA (mRNA) sequence and the absence of the mutant PGRN allele was confirmed in the reverse transcriptase-polymerase chain reaction (RT-PCR) product, which supported the model of haploinsufficiency for PGRN-linked disease. In a second familial study, clinical, radiological, genetic, and pathological studies were performed to contrast clinical features of the affected members. Sequencing PGRN revealed a novel, heterozygous cytosine-adenine dinucleotide deletion in exon 11 (g.2988_2989delCA, P439_R440fsX6). The proband`s clinical diagnosis was frontotemporal dementia and parkinsonism (FTDP). The proband’s brother with the same mutation presented initially as a progressive non-fluent aphasia (PNFA), and later evolved into a CBS. Pathological analysis revealed Frontotemporal Lobar Degeneration-Ubiquitin (FTLD-U)/ TAR DNA-binding protein 43 (TDP43) positive pathology. The next studies shift away from pathogenic mechanisms to focus on brain-behavioural correlations and phenotypic heterogeneity in a prospective sample of 31 CBS cases. We provide the first direct correlative analysis between the severity of ideomotor apraxia, a common sign in CBS, and cerebral SPECT perfusion imaging. Reductions in perfusion within the left inferior parietal lobule (t=5.7, p=0.03, Family-Wise Error [FWE] corrected), including the left angular gyrus (t=5.7, p=0.02, FWE corrected), were associated with more severe ideomotor apraxia. We stratified the sample into CBS presenting with early motor features (CBS-M; n=9) or early dementia (CBS-D; n=22), which identified that CBS-M were more likely to have cortical sensory loss than CBS-D (p=0.005). In contrast, the presence of aphasia was found to be more common and severe in CBS-D compared to CBS-M (p=0.02). CBS-M patients had significantly reduced perfusion in the right supplementary and premotor areas compared to CBS-D (p<0.05).

A cirrose é caracterizada por fibrose e por nódulos regenerativos que resultam na desorganização da arquitetura tecidual, sendo considerado um estágio irreversível. A administração de fatores hepatotróficos exógenos (FHE) poderia estimular a proliferação celular de células hepáticas e reduzir a cirrose induzida em ratos. Deste modo, os FHE atuariam na remodelação da matriz extracelular (ECM). Os objetivos desse trabalho foram avaliar os efeitos dos FHE em ratos cirróticos induzidos experimentalmente por tioacetamida. Foram realizadas análises histopatológicas, imunoistoquímica para BrdU, mensuração de colágeno, microscopia eletrônica de varredura, análises bioquímicas de função hepática e avaliação da expressão gênica de colágeno &alpha;1, TGF&beta;1, TIMP I, MMP 2 e Plau, por PCR em tempo real. Após administração de FHE obteve-se diminuição da expressão gênica dos genes fibrogênicos: colágeno&alpha;1, TGF&beta;1, TIMP I e MMP 2. Durante a remodelação da ECM foram observadas melhoras morfofuncionais, com diminuição do número de nódulos regenerativos parenquimais, diminuição da espessura dos septos fibrosos e reaparecimento de veias centrolobulares. Foi observado aumento do peso e volume do fígado dos ratos, assim como aumento na relação fígado/carcaça. Os animais tratados com FHE apresentaram redução de 29,62% do colágeno parenquimal total, quando comparados com sua própria biópsia antes do tratamento. Animais não submetidos ao tratamento com FHE tiveram um acréscimo de 8,7% de colágeno. Os índices de função hepática revelaram decréscimo significante nos níveis de gamaglutamiltranspeptida (GGT), alanina aminotransferase e aspartato aminotransferase. Desta forma, os FHE atuaram na remodelação da matriz extracelular hepática em fígados cirróticos pela diminuição da expressão de genes fibrogênicos e não necessariamente pelo aumento da expressão de genes fibrolíticos. Ademais, animais cirróticos apresentaram em seu fígado e intestino progranulina, um novo fator de crescimento. Propomos, dessa forma, a utilizalção da progranulina como um possível marcador clínico e alvo terapêutico para doenças hepáticas. / Cirrhosis is characterized by fibrosis and regenerative nodules, which result in the disorganization of the hepatic architecture, being considered an irreversible situation. The administration of exogenous hepatotrophic factors (EHF) could stimulate hepatic regeneration in hepatocytes cells and reduce the cirrhosis induced in rats. The aim of this work was to evaluate the effect of EHF in rat cirrhosis induced experimentally by thioacetamide. It was carried out histopathologics analysis; BrdU imunoperoxidase, collagen measurement, scanning electron microscopy; biochemical analysis for hepatic function and analysis on genic expression for collagen &alpha;1, TGF&beta; 1, TIMP I, MMP 2, and Plau by real time PCR. After the EHF administration, it was observed a reduction in the expression of fibrogenics genes as: collagen&alpha;1, TGF&beta;1, TIMP I and MMP 2. During the extracellular matrix (ECM) remodelation morphofuntional improvements were observed, with decrease of regenerative nodules and fibrous septs thickness as well as reappearance of central vein. It was observed increase in liver weight, volume and in the relation liver/carcass. The animals treated with EHF had a reduction of 29.62% in the total collagen when compared with their own biopsy before treatment, while the non-treated animals had an increase of 8,7%. The index of hepatic functions had significant improvement in the levels of gamaglutamiltranspeptida (GGT), alanine aminotransferase and aspartate aminotransferase. Therefore, the EHF acts on the extracellular matrix remodelation though reduction of fibrogenics gene expression and not necessarily by fibrolitics genes expression increase. In addiction, we have found progranulin, a new growth factor, in liver and intestine of cirrhotic animals. Hence, we propose the utilization of progranulin as a clinical marker and a therapeutic target for hepatic deseases.

No description available.

No description available.