Gliové buňky a jejich role v amyotrofické laterální skleróze

Amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease) is a progressive neurodegenerative disorder. It affects upper and lower motor neurons in the brain motor cortex, the brain stem and the spinal cord, causing their death, which results in denervation of voluntary muscles. Progressive muscle weakness and atrophy throughout the entire body gradually leads to worsening of the ability to move, speak, chew, swallow and eventually breath. Ultimately it results in affected individual's death due to respiratory muscle failure. Although first identified in 1869, no cure for ALS has been yet found. While early studies focused mainly on the research of motor neurons themselves, the attention has shifted towards glial cells in the past two decades. Glial cells are essential for proper neuron functioning and survival and it appears that they play a major role in ALS progression. The goal of this thesis is to review and summarize findings on the role of glial cells in ALS over the last years, focusing on four specific types of glial cells, namely astrocytes, microglia, oligodendrocytes and NG2-glia. Key words: amyotrophic lateral sclerosis, ALS, motor neuron, glia, astrocyte, microglia, oligodendrocyte, NG2-gliaAmyotrofická laterální skleróza (ALS, též známá jako Lou Gehrigova choroba) je progresivní neurodegenerativní onemocnění. Postihuje horní i dolní motorické neurony v motorické kůře mozku, v mozkovém kmeni a míše a způsobuje jejich smrt, následkem čehož dochází k denervaci svalů. To v důsledku vede ke slabosti a svalové atrofii celého těla, postupně dochází ke ztrátě schopnosti pohybu, mluvení, žvýkání a polykání, a nakonec i dýchání, což má za následek úmrtí postiženého jedince. Přestože ALS byla popsána již v roce 1869, snahy o nalezení léku jsou zatím bezúspěšné. Zatímco dřívější studie se zaměřovaly přímo na motorické neurony, pozornost vědecké obce se během posledních let přesunula ke gliovým buňkám. Gliové buňky jsou nezbytné pro správné fungování a přežití neuronů a zřejmě hrají důležitou roli při vzniku a progresi ALS. Cílem této práce je shrnout poznatky o roli gliových buněk při ALS za poslední roky, se zaměřením na čtyři konkrétní typy glií, jmenovitě astrocyty, mikroglie, oligodendrocyty a NG2-glie. Klíčová slova: amyotrofická laterální skleróza, ALS, motorické neurony, gliové buňky, astrocyty, mikroglie, oligodendrocyty, NG2-glieDepartment of Cell BiologyKatedra buněčné biologieFaculty of SciencePřírodovědecká fakult

Nanomecánica de proteínas neurotóxicas: características moleculares comunes en el inicio de la cascada de neurogeneración

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 15-03-201

Occupational hazards and radiation safety in veterinary practice including zoo veterinary practice in Australia

This thesis contains reviews and research on the occupational hazards of zoo veterinary practitioners in Australia. Although occupational hazards have long been recognised in the veterinary profession, little information is available on the number and magnitude of injuries to veterinarians in Australia, the United Kingdom or the United States. Apart from anecdotal accounts and some limited data, most of the available information is on occupational zoonoses, generally well recognized by veterinarians. Other occupational hazards to which veterinarians are exposed have received scant attention. The veterinary practitioner in a zoo environment has to treat a range of captive wild species which are much more unpredictable and dangerous than domesticated animals. A comprehensive study on occupational hazards sustained by veterinarians in zoological gardens has not been undertaken in Australia. Only one study had been undertaken in the US amongst zoo veterinarians, while comprehensive may not be able to be transposed to zoos in Australia as the species held in Australian zoos differ from those in the US. Personal communication with some senior veterinarians in the zoological gardens in Australia, have elicited further information on the prevalence of occupational hazards sustained by the zoo and wildlife park veterinarians. The prevalence of physical hazards including radiation, chemical and biological hazards reported by veterinary practitioners and the author\u27s own experience as a veterinary practitioner, chairman of the safety committee, member of the animal ethics committee and manager, research In the zoological gardens in Perth, Western Australia have demonstrated a need for a comprehensive study on occupational hazards prevalent among zoo veterinarians. To investigate the occupational hazards including radiological hazards amongst zoo veterinarians in Australia, a self-administered 14-page comprehensive questionnaire comprising 58 questions was mailed to 27 practising zoo veterinarians in Australia. The questionnaire focused on physical injuries, chemical exposures, allergic and irritant reactions, biological exposures, radiological hazards including problems encountered with x-ray machines, use of protective gear and ancillary equipment for radiography, personnel involved in x-ray procedures and in restraining animals, compliance with the Australian National Health and Medical Research Council (NHMRC) Code of Practice (1982), Radiation Safety Regulations (1988) and National Standard for Limiting Occupational Exposure to Ionising Radiation (1995) The result of the study revealed that 60% of the participants sustained physical injuries such as crushes, bites and scratches inflicted by a range of species with some Injuries requiring medical treatment. Also, 50% of the participants suffered from back injuries while 15% reported fractures, kicks, bites necessitating hospitalization. Ninety percent of the participants sustained needlestick injuries ranging from one to 16+ times. Other significant findings include: necropsy injuries, animal allergies, formaldehyde exposure, musculoskeletal Injuries and zoonotic infections. The survey also identified that veterinary practitioners and their staff were exposed to radiation by not complying with the National Health and Medical Research Council (NHMRC) Australian Code of Practice for the Safe Use of Ionising Radiation (1982) which has been framed to minimize exposure to ionising radiation. The majority of the veterinarians in the study group indicated that radiation exposure Is a major occupational hazard to the veterinary profession. Subsequent to the review and research, discussions were held with few senior zoo veterinarians, the Registrar of the Veterinary Surgeons Board and a number of practising senior veterinarians In Australia to collect information on occupational hazards. Additional information was obtained on occupational injuries sustained by the zoo veterinarians through formal discussions with the Director and the two senior veterinarians In the zoological gardens in Sri Lanka. The discussions with the veterinary practitioners in government and private practice revealed that veterinarians experienced a range of occupational hazards including exposure to rabies. Discussions with the dean and the professor of the animal science department focused on the nature of injuries and preventive strategies. In order to obtain information on occupational hazards in the health care industry, the professor of anatomy of the faculty of medicine and a senior surgeon in Sri Lanka were interviewed. This study identified that the zoo veterinarians are routinely exposed to a wide range of occupational hazards. The literature review among veterinary practitioners In US, UK, Australia and Canada have also identified numerous occupational hazards sustained by the veterinarians. The discussions held in Sri Lanka with the professionals in veterinary and health care industry showed that occupational injuries have been common amongst them and they do not have appropriate preventive guidelines in place. This thesis has incorporated recommendations in the form of preventive strategies for minimizing occupational hazards among veterinary practitioners both in zoological gardens and veterinary practices In Australia and in the developed and developing countries

Investigating the role of ADAM17 in human cytomegalovirus infection

Human cytomegalovirus (HCMV) is one of the most widespread, highly successful herpesviruses, establishing a life-long viral infection in humans. HCMV has been described as a paradigm of immune evasion able to manipulate many immune functions in the host. One of the host manipulation strategies employed by HCMV is the downregulation of a disintegrin and metalloproteinase 17 (ADAM17) – an important ectodomain shedding protease responsible for cleaving over a 100 substrates including many immunoregulatory molecules, such as receptors, cytokines, chemokines and adhesion molecules. Synergistic action of viral UL148 and UL148D result in a rapid ADAM17 downregulation from the surface of HCMV-infected cells. This thesis explores the mechanism and consequences of ADAM17 impairment by HCMV genes UL148 and UL148D, demonstrating the significance of ADAM17 downregulation in HCMV infection. UL148 and UL148D were shown to interfere with ADAM17 maturation, resulting in expression of only the intracellular immature precursor, and absence of mature ADAM17 on the surface of wildtype HCMV-infected cells. The mechanism of ADAM17 impairment was shown to be complex, suggesting that UL148 and UL148D act to downregulate ADAM17 via distinct mechanisms, with a possibility of a third viral gene involved in the process. The global consequences of ADAM17 downregulation by HCMV were analysed using proteomics and validated using biochemical and flow cytometric techniques, revealing that this virus manipulation impacted multiple cell surface and secreted host proteins. This included stabilisation of Vasorin, Jagged1, Nectin1 and Endothelial protein C receptor (EPCR), as well as a number of viral proteins. Other known ADAM17 targets were not stabilised, suggesting specific control by HCMV. The functional consequences of these changes to the levels of secreted and soluble proteins were tested and revealed the importance of ADAM17 impairment in regulatory T cell and NK cell function; however with so many ADAM17 substrates stabilised on cell surface as a result of HCMV infection, many other pathways are likely also affected