A lesão pulmonar aguda (LPA) é caracterizada por inflamação pulmonar de início súbito com recrutamento de polimorfonucleares e liberação de mediadores próinflamatórios. É uma condição grave que evolui com óbito em aproximadamente 40% dos casos. Diversos estudos que elucidaram a fisiopatologia da LPA, o tratamento ainda é insatisfatório. O sistema colinérgico anti-inflamatório foi descrito no pulmão e está relacionado a um reflexo via nervo vago que inibe a liberação de citocinas inflamatórias por efeitos relacionados a ação da acetilcolina em receptores nicotínicos. Nossa hipótese é de que a redução de VAChT, que está relacionada ao déficit na liberação de ACh, module a resposta inflamatória pulmonar em modelo de LPS. Objetivo: 1. Avaliar se a deficiência de VAChT modula a resposta pulmonar em animais geneticamente modificados; 2. Avaliar se a deficiência colinérgica induzida por redução de VAChT está envolvida na resposta pulmonar ao LPS e elucidar alguns mecanismos envolvidos; 3. Avaliar o potencial terapêutico do PNU, um agonista de alfa7nAChR nas alterações funcionais e histopatológicas em modelo de LPA em animais C57Bl6. Metodologia: Foram utilizados camundongos machos geneticamente modificados mutante (VAChT KDHOM) ou selvagem (WT) e C57BL/6. Inicialmente avaliamos a função pulmonar e a histopatologia pulmonar em animais VAChT KDHOM. Após, animais WT e VAChT KDHOM receberam instilação intranasal de LPS ou salina e a resposta inflamatória foi avaliada de 1,5h até 72 horas após. Ainda, foi avaliado a resposta pulmonar em VAChT KDHOM e WT após a instilação de LPS intraperitoneal. Por fim, animais C57BL/6 instilados com LPS intranasal, receberam tratamento prévio ou após com PNU, agonista do receptor nicotínico alfa7. Resultados: Animais mutante apresentaram maior quantidade de células recuperadas no lavado bronco alveolar (LBA) e aumento de citocinas próinflamatórias, aumento de edema peribrônquico e piora da função pulmonar. Ainda, observamos aumento da expressão de NF-kB e redução de JAK2. A deficiência de VAChT induziu aumento de células inflamatórias em animais que receberam LPS somente em 1.5h após a indução, sendo os valores iguais ao dos animais WT em 24 e 72 horas. Nos animais WT, o estimulo do receptor nicotínico melhora a inflamação, enquanto o estímulo de receptores muscarínicos parece contribuir com a piora da resposta da inflamação pulmonar. Os efeitos do PNU parecem que dependem da via colinérgica intacta, uma vez que esta droga não teve o mesmo efeito em animais mutante. Entretanto, o tratamento com PNU em animais C57BL/6 reduziu a inflamação, a produção de citocinas, a deposição de colágeno no tecido pulmonar e os níveis de MMP-2, MMP-9 e TIMP-1, melhorando a função pulmonar. Estes efeitos parecem estar associados a redução de macrófagos perfil M1, e a inibição de NF-kB. Conclusão: Estes dados claramente demonstram que o sistema colinérgico anti-inflamatório está envolvido no controle da resposta inflamatória pulmonar, seja na manutenção da homeostasia ou ainda nas fases iniciais do desenvolvimento da LPA. Ainda, está claro que o estímulo de receptores nicotínicos tem grande potencial como alvo terapêutico a ser explorado na SDRA / Acute lung injury (ALI) is characterized by acute lung inflammation with recruitment of polymorphonuclear and release of proinflammatory mediators. It is a severe condition since leads to death 40% of the cases. Several studies have elucidated the pathophysiology of ALI, however the treatment is still unsatisfactory. The anti-inflammatory cholinergic system was described in the lung and is related to a vagal nerve reflex that inhibits the release of inflammatory cytokines by the action o ACh on nicotinic receptors. Our hypothesis is that the VAChT reduction, which is related to the deficit in the release of ACh, modulates the pulmonary inflammatory response in a model of LPS. Aim: 1. To assess whether VAChT deficiency modulates the pulmonary response in genetically modified animals; 2. Assess whether cholinergic deficiency induced reduction VAChT is involved in pulmonary response to LPS and elucidate some mechanisms involved; 3. To evaluate the therapeutic potential of PNU, an agonist alfa7nAChR, in functional and histological changes in C57BL6 mice with LPA. Methods: Mutant genetically modified male mice (VAChT KDHOM) or wild (WT) and C57BL/6 were used. First, we evaluated lung function and lung histopathology in VAChT KDHOM animals. After, WT animals and VAChT KDHOM received intranasal instillation of LPS or saline and the inflammatory response was assessed 1.5 hours to 72 hours. Moreover, the pulmonary response was evaluated in WT and VAChT KDHOM after instillation of LPS intraperitoneally. Finally, C57BL6 instilled with intranasal LPS received prior or post-treatment with PNU, an alfa7 nicotinic receptor agonist. Results: Mutant animals had higher number of cells recovered in brochoalveolar lavage (BAL) and increased pro-inflammatory cytokines, peribronchial edema and worsening of lung function. Still, there was an increase of NF_kB expression and reduction of JAK2. The VAChT deficiency induced increase in inflammatory cells in animals receiving LPS only 1.5h after the LPS instilation, and the values were similar to WT in 24 and 72 hours. In WT mice, the stimulation of the nicotinic receptor improves inflammation, while the stimulation of muscarinic receptors appears to contribute to the worsening of the pulmonary inflammatory response. The effects of PNU seem to depend on the intact cholinergic pathway, since this drug had no effects on mutant animals. However, treatment with PNU in C57BL6 reduced pulmonar inflammation, cytokine production, collagen deposition in lung tissue and the levels of MMP-2, MMP-9 and TIMP-1, improving pulmonary function. These effects appear to be associated with reduced profile M1 macrophages and the inhibition of NF-kB. Conclusion: These data clearly demonstrate that the anti-inflammatory cholinergic system is involved in the control of lung inflammatory response, both to maintain the lung homeostasis or in the early stages of the development of ALI. Finally, it is clear that the stimulation of nicotinic receptors has great potential as a therapeutic target to be explored in ARDS

Congenital myasthenic syndromes (CMS) are a group of heterogeneous disorders caused by mutations in genes encoding for proteins that are essential for neuromuscular transmission. All CMS share the clinical feature of fatigable muscle weakness. The differential diagnosis of CMS is wide, with a range of diseases going from autoimmune myasthenia gravis to muscle disorders. In this thesis, it was shown that measuring antibodies to clustered acetylcholine receptors (AChRs) by cell-based assay is helpful in the differential diagnosis of CMS. The findings of the current investigations showed that mutations in COL13A1, encoding the Collagen Type XIII α1 chain, were responsible for the symptoms of several patients with previously undefined myasthenias. In addition, this work described the clinical and complementary features of a novel CMS subtype due to mutations in the glycosylation pathway gene GMPPB. Investigations on a novel MUSK missense mutation (p.Ala617Val) uncovered previously unrecognised mechanisms of how levels of MuSK phosphorylation are critical to maintain synaptic structure, and guided suitable treatment for the patient. The study on the clinical and molecular basis of stridor, a novel clinical feature recently identified in patients with DOK7-CMS, prompted the identification of a novel DOK7 isoform, which warrants further investigation to elucidate its role in AChR clustering. Finally, the therapy of patients with severe AChR-deficiency was optimised thanks to a case series study that showed a robust improvement following the addition of β2-adrenergic agonists to their long-term treatment regime that included pyridostigmine.

A lesão pulmonar aguda (LPA) é caracterizada por inflamação pulmonar de início súbito com recrutamento de polimorfonucleares e liberação de mediadores próinflamatórios. É uma condição grave que evolui com óbito em aproximadamente 40% dos casos. Diversos estudos que elucidaram a fisiopatologia da LPA, o tratamento ainda é insatisfatório. O sistema colinérgico anti-inflamatório foi descrito no pulmão e está relacionado a um reflexo via nervo vago que inibe a liberação de citocinas inflamatórias por efeitos relacionados a ação da acetilcolina em receptores nicotínicos. Nossa hipótese é de que a redução de VAChT, que está relacionada ao déficit na liberação de ACh, module a resposta inflamatória pulmonar em modelo de LPS. Objetivo: 1. Avaliar se a deficiência de VAChT modula a resposta pulmonar em animais geneticamente modificados; 2. Avaliar se a deficiência colinérgica induzida por redução de VAChT está envolvida na resposta pulmonar ao LPS e elucidar alguns mecanismos envolvidos; 3. Avaliar o potencial terapêutico do PNU, um agonista de alfa7nAChR nas alterações funcionais e histopatológicas em modelo de LPA em animais C57Bl6. Metodologia: Foram utilizados camundongos machos geneticamente modificados mutante (VAChT KDHOM) ou selvagem (WT) e C57BL/6. Inicialmente avaliamos a função pulmonar e a histopatologia pulmonar em animais VAChT KDHOM. Após, animais WT e VAChT KDHOM receberam instilação intranasal de LPS ou salina e a resposta inflamatória foi avaliada de 1,5h até 72 horas após. Ainda, foi avaliado a resposta pulmonar em VAChT KDHOM e WT após a instilação de LPS intraperitoneal. Por fim, animais C57BL/6 instilados com LPS intranasal, receberam tratamento prévio ou após com PNU, agonista do receptor nicotínico alfa7. Resultados: Animais mutante apresentaram maior quantidade de células recuperadas no lavado bronco alveolar (LBA) e aumento de citocinas próinflamatórias, aumento de edema peribrônquico e piora da função pulmonar. Ainda, observamos aumento da expressão de NF-kB e redução de JAK2. A deficiência de VAChT induziu aumento de células inflamatórias em animais que receberam LPS somente em 1.5h após a indução, sendo os valores iguais ao dos animais WT em 24 e 72 horas. Nos animais WT, o estimulo do receptor nicotínico melhora a inflamação, enquanto o estímulo de receptores muscarínicos parece contribuir com a piora da resposta da inflamação pulmonar. Os efeitos do PNU parecem que dependem da via colinérgica intacta, uma vez que esta droga não teve o mesmo efeito em animais mutante. Entretanto, o tratamento com PNU em animais C57BL/6 reduziu a inflamação, a produção de citocinas, a deposição de colágeno no tecido pulmonar e os níveis de MMP-2, MMP-9 e TIMP-1, melhorando a função pulmonar. Estes efeitos parecem estar associados a redução de macrófagos perfil M1, e a inibição de NF-kB. Conclusão: Estes dados claramente demonstram que o sistema colinérgico anti-inflamatório está envolvido no controle da resposta inflamatória pulmonar, seja na manutenção da homeostasia ou ainda nas fases iniciais do desenvolvimento da LPA. Ainda, está claro que o estímulo de receptores nicotínicos tem grande potencial como alvo terapêutico a ser explorado na SDRA / Acute lung injury (ALI) is characterized by acute lung inflammation with recruitment of polymorphonuclear and release of proinflammatory mediators. It is a severe condition since leads to death 40% of the cases. Several studies have elucidated the pathophysiology of ALI, however the treatment is still unsatisfactory. The anti-inflammatory cholinergic system was described in the lung and is related to a vagal nerve reflex that inhibits the release of inflammatory cytokines by the action o ACh on nicotinic receptors. Our hypothesis is that the VAChT reduction, which is related to the deficit in the release of ACh, modulates the pulmonary inflammatory response in a model of LPS. Aim: 1. To assess whether VAChT deficiency modulates the pulmonary response in genetically modified animals; 2. Assess whether cholinergic deficiency induced reduction VAChT is involved in pulmonary response to LPS and elucidate some mechanisms involved; 3. To evaluate the therapeutic potential of PNU, an agonist alfa7nAChR, in functional and histological changes in C57BL6 mice with LPA. Methods: Mutant genetically modified male mice (VAChT KDHOM) or wild (WT) and C57BL/6 were used. First, we evaluated lung function and lung histopathology in VAChT KDHOM animals. After, WT animals and VAChT KDHOM received intranasal instillation of LPS or saline and the inflammatory response was assessed 1.5 hours to 72 hours. Moreover, the pulmonary response was evaluated in WT and VAChT KDHOM after instillation of LPS intraperitoneally. Finally, C57BL6 instilled with intranasal LPS received prior or post-treatment with PNU, an alfa7 nicotinic receptor agonist. Results: Mutant animals had higher number of cells recovered in brochoalveolar lavage (BAL) and increased pro-inflammatory cytokines, peribronchial edema and worsening of lung function. Still, there was an increase of NF_kB expression and reduction of JAK2. The VAChT deficiency induced increase in inflammatory cells in animals receiving LPS only 1.5h after the LPS instilation, and the values were similar to WT in 24 and 72 hours. In WT mice, the stimulation of the nicotinic receptor improves inflammation, while the stimulation of muscarinic receptors appears to contribute to the worsening of the pulmonary inflammatory response. The effects of PNU seem to depend on the intact cholinergic pathway, since this drug had no effects on mutant animals. However, treatment with PNU in C57BL6 reduced pulmonar inflammation, cytokine production, collagen deposition in lung tissue and the levels of MMP-2, MMP-9 and TIMP-1, improving pulmonary function. These effects appear to be associated with reduced profile M1 macrophages and the inhibition of NF-kB. Conclusion: These data clearly demonstrate that the anti-inflammatory cholinergic system is involved in the control of lung inflammatory response, both to maintain the lung homeostasis or in the early stages of the development of ALI. Finally, it is clear that the stimulation of nicotinic receptors has great potential as a therapeutic target to be explored in ARDS

Οι νικοτινικοί υποδοχείς της ακετυλοχολίνης (nAChRs) ανήκουν στην υπερ-οικογένεια των ιοντικών καναλιών που ενεργοποιούνται από τη δέσμευση ενός προσδέτη (LGICs) και αποτελούνται από πέντε ομόλογες υπομονάδες. Κάθε μονομερής υπομονάδα αποτελείται από μία Ν-τελική εξωκυττάρια περιοχή (ΕΚΠ), από τέσσερεις διαμεμβρανικές α-έλικες και από μία κυτταροπλασματική περιοχή. Στην ΕΚΠ βρίσκεται η χαρακτηριστική Cys-θηλιά της υπερ-οικογένειας, καθώς και οι θέσεις πρόσδεσης αγωνιστών και ανταγωνιστών του υποδοχέα. Οι γνώσεις μας γύρω από τη δομή των nAChRs προέρχονται κυρίως από κρυσταλλογραφικές δομές ομολόγων πρωτεϊνών δέσμευσης της ACh (AChBP) μαλακίων, από μια δομή του nAChR από ιχθείς του γένους Torpedo που προέρχεται από ηλεκτρονική μικροσκοπία, από την κρυσταλλογραφική δομή της α1-ΕΚΠ ποντικού σε σύμπλοκο με α-μπουγκαροτοξίνη (α-Btx) και από κρυσταλλογραφικές δομές δύο προκαρυωτικών LGICs. Παρά τη μεγάλη πρόοδο που πραγματοποιήθηκε με τα παραπάνω επιτεύγματα, ακόμη δεν έχει επιλυθεί πειραματικά η δομή ανθρώπινου υποδοχέα. Επίσης λίγα είναι γνωστά για την επίδραση της γλυκοζυλίωσης των ΕΚΠ στη λειτουργία του nAChR. Χρησιμοποιώντας ως εκμαγείο την κρυσταλλογραφική δομή του συμπλόκου α1-ΕΚΠ ποντικού/α-Btx δημιουργήθηκαν υπολογιστικά μοντέλα της ανθρώπινης α1-ΕΚΠ προσδεμένης στις τοξίνες α-μπουγκαροτοξίνη (α-Btx), α-κομπρατοξίνη (α-Cbtx), α-κωνοτοξίνη (α-Ctx) ImI και α-κωνοτοξίνη GI. Στα σύμπλοκα με α-Btx και α-Cbtx προστέθηκε η υδατανθρακική αλυσίδα, συνδεδεμένη με το κατάλοιπο Asn141, που συγκρυσταλλώθηκε μαζί με την α1-ΕΚΠ ποντικού. Για να μελετηθεί η δυναμική συμπεριφορά της αλληλεπίδρασης υποδοχέα-τοξίνης καθώς και η συνεισφορά των σακχάρων σε αυτήν πραγματοποιήθηκαν προσομοιώσεις Μοριακής Δυναμικής σε υδατικό περιβάλλον. Με τη χρήση υπολογιστικών εργαλείων για τη μελέτη των συμπλόκων προσδιορίστηκαν σε ατομικό επίπεδο οι αλληλεπιδράσεις που καθοδηγούν την πρόσδεση τοξινών στην α1-ΕΚΠ. Βρέθηκε ότι η υδατανθρακική αλυσίδα συμμετέχει δυναμικά στη δέσμευση της τοξίνης στον υποδοχέα. Τα σάκχαρα συγκλίνουν προς την προσδεμένη τοξίνη στηριζόμενα στα κατάλοιπα Ser187 και Trp184 της α1 υπομονάδας. Η τοξίνη επίσης μετακινείται φέρνοντας τη θηλιά Ι σε επαφή με τα σάκχαρα. Αναγνωρίστηκαν σημαντικές αλληλεπιδράσεις των σακχάρων με τα τοξινικά κατάλοιπα Thr6, Ser9, και Th15 της α-Btx και Thr6 και Pro7 της α-Cbtx. Επίσης επιβεβαιώθηκε η ύπαρξη μιας υδρόφιλης κοιλότητας στο εσωτερικό του υδρόφοβου πυρήνα της α1-ΕΚΠ, η οποία πιθανόν εμπλέκεται στο άνοιγμα του ιοντικού καναλιού του nAChR. Τα αποτελέσματα αυτά παρέχουν σημαντικά δεδομένα για την κατανόηση της επίδρασης της υδατανθρακικής αλυσίδας στη λειτουργία του υποδοχέα, η οποία μπορεί να αξιοποιηθεί στην αντιμετώπιση των πολλών παθολογικών καταστάσεων στις οποίες εμπλέκονται οι nAChRs. / Nicotinic acetylcholine receptors (nAChRs) belong to the superfamily of ligand-gated ion channels (LGICs). LGICs form homo- or hetero-pentamers of related subunits, and each of them consists of a N-terminal extracellular ligand-binding domain (ECD), four transmembrane α-helixes and an intracellular region. The characteristic Cys-loop of the superfamily is found in the ECD of each subunit. The ECD also contains binding sites for agonists and competitive antagonists. Our knowledge regarding the nAChR structure mainly derives from the X-ray crystal structures of the molluscan ACh-binding proteins (AChBPs), the electron microscopy structure of the Torpedo nAChR, the X-ray crystal structure of the mouse nAChR α1-ECD bound to α-bungarotoxin (α-Btx), and the X-ray crystal structures of two prokaryotic LGICs. Despite the progress made by these achievements, the determination of any human nAChR structure has not yet been accomplished. Furthermore, the effect of glycosylation on nAChR function has not yet been explored. Based on the crystal structure of the extracellular domain of the mouse nAChR α1 subunit bound to α-Btx we have generated in silico models of the human nAChR α1-ECD bound to the toxins α-bungarotoxin (α-Btx), α-cobratoxin (α-Cbtx), α-conotoxin (α-Ctx) ImI and α-conotoxin GI. In the case of the α1-ECD/α-Btx and α-Cbtx complexes, a Asn141-linked carbohydrate chain was modeled, its coordinates taken from the crystal structure of the mouse α1-ECD. To gain further insight into the structural role of glycosylation molecular dynamics (MD) simulations were carried out in explicit solvent so as to compare the conformational dynamics of the binding interface between nAChR α1 and the two toxins. The use of computational methods allowed the monitoring of the interactions that govern toxin binding. The MD simulations revealed the strengthening of the receptor-toxin interaction in the presence of the carbohydrate chain. A shift in the position of the sugars towards the bound toxin was observed. Residues Ser187 and Trp184 of nAChR act as critical anchor points for the stabilization of the sugar chain in a close position to the toxin. Toxin Finger I shifts closer to the mannoses, forming important toxin-sugar interactions that implicate residues Thr6, Ser9, and Thr15 of α-Btx, as well as Thr6 and Pro7 of α-Cbtx. Additionally the MD simulations of the human α1 ECD–toxin complexes confirmed the possible accommodation of two water molecules into a hydration cavity inside the hydrophobic core of the subunit, which may contribute to the gating mechanism of the receptor. These findings provide additional structural data that are intended to inspire biophysical studies on the functional role of glycosylation in the gating mechanism of nAChR and also guide the development of novel therapeutic agents for the treatment of nAChR-associated diseases.

A sepse causa uma alta taxa de mortalidade no mundo. A fisiopatologia da doença envolve uma rede complexa de mediadores inflamatórios que promovem a lesão de diversos tecidos, além de diversas alterações hemodinâmicas e disfunção do sistema nervoso autonômico (SNA). Assim sabe-se que o sistema nervoso cumpre um papel importante no controle da inflamação sistêmica mediante a via colinérgica anti-inflamatória (VCA) através do receptor nicotínico de acetilcolina alfa7 (alfa7nAChR). O uso das células-tronco mesenquimais (CTM) tem mostrado efeitos benéficos em diversos ensaios clínicos de doenças inflamatórias. Neste contexto, as células-tronco mesenquimais derivadas da geleia de Wharton do cordão umbilical (CTM-GW) tornam-se promissórias, uma vez que essas células são reconhecidas pela regulação da resposta imunológica, reparação neural, efeito anti-apoptose, assim como a melhora da sobrevida na sepse, em modelos experimentais. Nossa hipótese foi de que as CTM-GW poderiam cumprir um papel neuroimunomodulador através da VCA e atenuar a disfunção de múltiplos órgãos em um modelo animal de sepse de ligadura e punção do ceco (LPC). Inicialmente células da matriz do cordão umbilical foram isoladas e caracterizadas de acordo com o consenso internacional vigente. Ratos Wistar machos adultos foram subdivididos em grupos: 1) sham (operação simulada); 2) LPC; 3) LPC+CTM-GW (injetado 106 CTM-GW via intraperitoneal, i.p. 6 h após LPC) e 4) LPC+MLA+CTM-GW (MLA: Metillicaconitine, antagonista do alfa7nAChR, i.p., 5:30 h após LPC e 106 CTM-GW 6h após). Às 24 horas após LPC, foram avaliadas a função cardiovascular, hemodinâmica assim como os outros parâmetros. Interessantemente, o tratamento com CTM-GW na sepse atenuou a disfunção diastólica e protegeu a sensibilidade baroreflexa. Além disso, as CTM-GW estimularam a atividade autonômica, simpática e parassimpática no coração. Observamos que o tratamento celular induziu uma regulação da expressão do receptor alfa7nAChR e TLR4 no baço e no coração, assim como a redução da relação p-STAT3TYR705 e STAT3 total no baço. Outros efeitos importantes e adicionais foram a diminuição da infiltração de leucócitos e a regulação das citocinas pró-inflamatórias pelas células. O bloqueio da VCA usando MLA confirmou que o receptor alfa7nAChR pode ser um provável alvo, chave da ação das CTM entre vários outros mecanismos envolvidos na resposta imune. Finalmente, as CTM-GW conseguiram reduzir a apoptose no pulmão e no baço independentemente da VAC reforçando o conceito de que as células-tronco tem efeitos diversos além da imuno-regulação. Em conclusão, as CTM-GW na sepse foram capazes de atenuar a lesão cardiopulmonar assim como modular a atividade autonômica, reduzindo a inflamação sistêmica, pelo menos em parte, através da via colinérgica anti-inflamatória. Indubitavelmente todos estes efeitos anteriormente descritos e em associação se demonstraram fundamentais no mecanismo de reparo e proteção tecidual em resposta a sepse. Mais estudos pré-clínicos e futuros testes clínicos precisam ser realizados para maior compreensão destes mecanismos bem como uma possível validação terapêutica / Sepsis induces organ dysfunction due to overexpression of the inflammatory host response, involving cardiorespiratory and autonomic dysregulation, thus increasing the associated morbidity and mortality. The cholinergic anti-inflammatory pathway (CAP) is mediated by nervous system through alpha7 nicotinic acetylcholine receptor (alpha7nAChR). This receptor has an important role in systemic inflammation control. Wharton\'s jelly-derived mesenchymal stem cells (WJ-MSCs) are known to express genes and secreted factors related to neurological and immunological protection, as well as to improve survival in experimental sepsis. We hypothesized that WJ-MSCs play a modulatory role through the CAP and attenuate sepsis-induced organ injury in a cecal ligation and puncture (CLP) model. Rats were randomly divided into 4 groups: 1) Control (sham-operated); 2) submitted to CLP without treatment; 3) submitted to CLP and treated with 106 WJ-MSCs 6 h later and 4) CLP+MLA+WJ-MSC group (MLA: Methyllycaconitine, alpha7nAChR antagonist). All experiments were performed 24 h post-surgery. Echocardiographic parameters and heart rate variability were assessed. Importantly, treatment with WJ-MSCs attenuated diastolic heart failure and recovered barorreflex sensitivity. Moreover, WJ-MSCs injection increased cardiac sympathetic and cardiovagal activity. In cardiac and splenic tissue, WJ-MSC treatment downregulated TLR4 and alpha7nAChR expression, as well as it reduced p-STAT3/Total STAT3 ratio in the spleen. In addition, WJ-MSC reduced leukocyte infiltration and pro-inflammatory cytokines, which only were abolished by MLA treatment. Finally, WJ-MSC treatment diminished apoptosis in lung and spleen tissue. Together these findings suggest that treatment with WJ-MSCs appears to protect against sepsis-induced organ injury reducing systemic inflammation, at least in part, through cholinergic anti-inflammatory pathway

Movement is a prerequisite for normal fetal development and growth. Intrauterine movement restrictions cause a broad spectrum of disorders in which the unifying feature is a reduction or lack of fetal movement, giving rise to the term fetal akinesia deformations sequence (FADS [OMIM 208150]). FADS corresponds to a clinically and genetically heterogeneous constellation of properties and is characterized by multiple joint contractures, facial abnormalities, and lung hypoplasia as a result of the decreased in utero movement of the fetuses. Affected babies are often prematurely and stillborn, and those born alive typically die within minutes or hours after birth. The genetic causes for this fatal disorder are ill-defined as a genetic diagnosis is rarely executed, but mutations in three genes, namely RAPSN, DOK7, and MUSK, as well as in the subunits of the muscular nicotinic acetylcholine receptor (AChR) have been described. These mutations are thought to affect neuromuscular junctions, although this has not been proven experimentally.The nucleoporin NUP88 is a constituent of the nuclear pore complex (NPC), the gate for all trafficking between the nucleus and the cytoplasm. NUP88 resides on both the cytoplasmic and the nuclear side of NPCs, and it is found in two distinct subcomplexes. It associates with NUP214 and NUP62 on the cytoplasmic face, while on the nuclear side NUP88 binds NUP98 and the intermediate filament protein lamin A. The NUP88-NUP214-NUP62 complex plays an essential role in the nuclear export of a subset of proteins and pre-ribosomes, which is mediated by the nuclear export receptor CRM1. NUP88 in particular somewhat participates in the nuclear export of NF-κB proteins in a CRM1-dependent manner. Moreover, NUP88 is frequently overexpressed in a variety of human cancers, and its role in cancer appears linked to the deregulation of the anaphase-promoting complex. Here, we report the first Mendelian disorders caused by mutations in NUP88 and with that the first lethal developmental human disease due to mutations in a nuclear pore component. We demonstrate that biallelic mutations in NUP88 are likely to cause fetal akinesia of the Pena-Shokeir subtype. We confirm in zebrafish that loss of NUP88 impairs movement and the mutations identified in the affected individuals resemble a loss-of-function phenotype. We show that loss of NUP88 affects expression and localization of rapsyn, the protein encoded by RAPSN, in human and mouse cell lines, and patient samples. Consistent with altered rapsyn, AChR clustering and neuromuscular junction formation in zebrafish are abnormal. We therefore propose that defective NUP88 function cause FADS by affecting neuromuscular junction formation.Keywords: Nuclear pore complex, NUP88, Fetal Akinesia Deformation Sequence, rapsyn, acetylcholine receptor clustering, synaptic transmission, fetal development, inherited developmental disorder. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

ColQ est un collagène spécifique qui ancre l’acétylcholinestérase (AChE) dans la fente synaptique de la jonction neuromusculaire (JNM). L'importance du complexe AChE-ColQ dans la physiologie humaine de cette synapse est soulignée par l’identification de mutations dans le gène codant pour ColQ qui conduisent à un syndrome myasthénique congénital (SMC) associé à une déficience en AChE. Le déficit en AChE a, jusqu’à présent, été considéré comme l’unique facteur responsable des symptômes observés chez les patients ainsi que des défauts de la JMN chez le modèle de souris SMC (souris déficiente pour ColQ). Toutefois, ces symptômes sont complexes et l’absence d’AChE ne peut probablement pas expliquer tous les symptômes. Nous avons montré auparavant que ColQ participait à la formation de la synapse ce qui expliquerait les symptômes observés chez les patients et la souris modèle. En effet, nous avons pu montrer que ColQ contrôle l’agrégation du récepteur à l’acétylcholine (RACh) et de l’expression de gènes spécifiques de la synapse. En particulier, nous avons montré in vitro et in vivo, que l’absence de ColQ induit une augmentation du niveau des ARNm codant pour toutes les sous-unités de RACh et une expression réduite du niveau de leurs protéines. Des résultats préliminaires indiquent que cette augmentation de ces ARNm n’est pas transcriptionnelle. L’objectif de cette thèse est d’expliquer les mécanismes qui induisent l’augmentation du niveau des ARNm de AChR en l’absence de ColQ et les voies de signalisation qui relient ColQ au métabolisme des ARN du RACh. Notre hypothèse de travail a été que l'absence de ColQ stimule la stabilisation post-transcriptionnelle des ARNm codant pour les sous-unités du RACh via la protéine HuR. HuR est une protéine qui stabilise les ARNm quand elle se fixe sur les AU-richelement (ARE) dans la séquence 3’UTR. HuR est une protéine clé dans la myogenèse et la formation de la JNM parce qu’elle stabilise de manière post-transcriptionnelle de nombreux transcrits tels que myogénine, MyoD et AChE. Dans cette étude, nous montrons pour la première fois qu’un mécanisme post-transcriptionnel de stabilisation des ARNm est responsable de l’augmentation du niveau des ARNm du RACh via ColQ. De plus, nous constatons qu’en absence de ColQ, il y a une augmentation aux niveaux d’ARNm et de protéine de HuR. HuR est également capable de se lier au domaine ARE dans le 3’UTR des ARNm des sous-unités de AChR. De plus, l’interaction entre HuR et les ARNm du RACh augmente la stabilité et par conséquence les niveaux des transcrits du RACh. Trois conclusions importantes ressortent de ma thèse : nous démontrons que (1) en plus de la régulation transcriptionnelle, il existe des mécanismes de régulation post-transcriptionnlle du RACh (2) ColQ régule la stabilité des ARNm RACh via HuR médiée par MuSK (3) la voie de signalisation p38 contrôle les niveaux de HuR de manière dépendante de ColQ. Ensemble, ces résultats donnent un aperçu des voies de signalisation du muscle qui sont affectées par les mutations de ColQ conduisant à des SMC avec une déficience en AChE. Nos résultats mettront en évidence des nouvelles cibles moléculaires spécifiques qui peuvent conduire au développement des interventions thérapeutiques dans le cadre de myasthénies congénitales. / ColQ is a specific collagen that anchors acetylcholinesterase (AChE) in the synaptic cleft of the neuromuscular junction (NMJ). The importance of AChE-ColQ complex in the physiology of this synapse has been highlighted by the identification of COLQ mutations in the human gene, leading to a congenital myasthenic syndrome (CMS) with AChE deficiency. The lack of AChE has been incriminated for the symptoms observed in patients along with NMJ defects in the CMS mouse model (ColQ-deficient). However, symptoms observed in the patients and mouse model of CMS with AChE deficiency are complex and AChE deficiency cannot account for all of them. We have demonstrated that ColQ could play a role per se in synapse formation which would explain some of the defects observed in patients and model mice. Indeed, we have shown that ColQ controls the clustering of Acetylcholine Receptors (AChR) and the expression of a number of specific synaptic genes. The most striking effect of the absence of ColQ is an upregulation of all AChR subunit mRNAs correlated by an increase in their protein levels. Preliminary results indicate that AChR mRNA upregulation is not transcriptional. This thesis deciphers the mechanisms that drive AChR mRNA upregulation in the absence of ColQ and the pathways that connect ColQ to the AChR RNA metabolism. Accordingly, we hypothesize that the absence of ColQ induces an upregulation of the stabilization of AChR subunit mRNAs, a post-transcriptional mechanism mediated by HuR. HuR is an RNA binding protein which stabilizes its target transcript by binding AU-rich elements (AREs) in their 3’UTR. HuR is critical during skeletal myogenesis and post-synaptic NMJ formation due to its stabilization of such transcripts as myogenin, MyoD and AChE. In this study, we show for the first time that a post-transcriptional mechanism of AChR mRNA stabilization is responsible for the ColQ mediated increase of AChR mRNAs. In support of these findings, the absence of ColQ also increased HuR mRNA and protein levels. We demonstrate that HuR is capable of binding to conserved ARE elements in the 3’UTR of AChR subunit mRNA. HuR’s interaction with AChR mRNA increased the stability of the transcripts, resulting in an increase in mRNA levels. Three major conclusions emerge from my thesis: we provide evidence that (1) in addition to transcriptional and assembly regulation of AChR, post-transcriptional mechanisms of AChR mRNA exist (2) ColQ regulates HuR mediated AChR stability through MuSK and (3) the p38 signalling pathway controls the levels of HuR in a ColQ dependent manner. Collectively, our data provides insight into the muscle signaling pathways which are affected by ColQ mutations leading to CMS with AChE deficiency. Thus, we have identified specific new molecular targets that may become important for the development of therapeutic interventions for patients with CMS.

Membrane protein dynamics is of great importance for living organisms. The precise localization of proteins composing a synapse on the membrane facing a nerve terminus is essential for proper functioning of the nervous system. In muscle fibers, the nicotinic acetylcholine is densely packed under the motor nerve termini. A receptor associated protein, rapsyn, acts as a linker between the receptor and the other components of the synaptic suramolecular assembly. Advances in fluorescence microscopy have allowed to measure the behavior of a single receptor in the cell membrane. In this work single-molecule microscopy was used to track the motion of ionotropic acetylcholine (nAChR) and serotonin (5HT3R) receptors in the plasma membrane of cells. We present methods for measuring single-molecule diffusion and their analysis. Single molecule tracking has shown a high dependence of acetylcholine receptors diffusion on its associated protein rapsyn. Comparing muscle cells that either express rapsyn or are devoid of it, we found that rapsyn plays an important role on receptor immobilization. A three-fold increase of receptor mobility was observed in muscle cells devoid of rapsyn. However, in these cells, a certain fraction of immobilized receptors was also found immobile. Furthermore, nAChR were strongly confined in membrane domains of few tens of nanometers. This showed that membrane composition and membrane associated proteins influence on receptor localization. During muscle cell differentiation, the fraction of immobile nAChR diminished along with the decreasing nAChR and stable rapsyn expression levels. The importance of rapsyn in nAChR immobilization has been further confirmed by measurements in HEK 293 cells, where co-expression of rapsyn increased immobilization of the receptor. nAChR is a ligand-gated ion-channel of the Cys-loop family. In mammals, members of this receptor family share general structural and functional features. They are homo- or hetero-pentamers and form a membrane-spanning ion channel. Subunits have three major regions, an extracellular ligand binding domain, a transmembrane channel and a large intracellular loop. 5HT3R was used as a model to study the effect of this loop on receptor mobility. Single-molecule tracking experiments on receptors with progressively larger deletions in the intracellular loop did not show a dependence of the size of the loop on the diffusion coefficient of mobile receptors. However, two regions were identified to play a role in receptor mobility by changing the fractions of immobile and directed receptors. Interestingly, a prokaryotic homologue of cys-loop receptors, ELIC, devoid of a large cytoplasmic loop was found to be immobile or to show directed diffusion similar as the wild-type 5HT3R. The scaffolding protein rapsyn stabilizes nAChR clusters in a concentration dependent manner. We have measured the density and self-interactions of rapsyn using FRET microscopy. Point-mutations of rapsyn, known to provoke myopathies, destabilized rapsyn self-interactions. Rapsyn-N88K, and R91L were found at high concentration in the cytoplasm suggesting that this modification disturbs membrane association of rapsyn. A25V was found to accumulate in the endoplasmic reticulum. Fluorescent tools to measure intracellular concentration of calcium ions are of great value to study the function of neurons. Rapsyn is highly abundant at the neuromuscular junction and thus is a genuine synaptic marker. A fusion protein of rapsyn with a genetically encoded ratiometric calcium sensor has been made to probe synapse activity. This thesis has shown that the combined use of biologically relevant system and modern fluorescence microscopy techniques deliver important information on pLGIC behaviour in the cell membrane. / <p>QC 20151217</p>

Nicotine exerts a therapeutic effect in ulcerative colitis (UC) but the mechanism underlying this effect, is not clear. However, this effect may imply that nicotine has some, as yet to be discovered, effect on the immune system. The aim of the work described in this thesis was to characterise the nicotinic acetylcholine receptors (nAChRs) on human peripheral blood lymphocytes in term of receptor subtype. To achieve this, a combination of radioligand binding assays, pharmacological and molecular biological techniques were used. The data obtained from the binding studies suggested that the presence of one binding site for (-)- nicotine on human peripheral blood lymphocytes with a Kd 15 ± 5.759 nM (1.5 ± 5.759 x 10-8 M) and Bmax 2253 ± 409 sites/cell. The competition studies showed that ligands competing with [3H]-(-)-nicotine were (-)-nicotine, epibatidine and α-bungarotoxin, while others ligands for nAChRs displaced radiolabelled nicotine in insignificant quantities. Thus, radioligand-binding experiments suggest that the binding site for nicotine on human peripheral blood lymphocytes is a nAChR containing α7 and possibly α4 or/and b2 containing nAChR subunits. No evidence was obtained to suggest the presence of a non-cholinergic nicotine receptor. Furthermore, considerable subject to subject variation in the specific binding of radiolabelled nicotine was observed. Because of this only tentative conclusions could be drawn from radioligand binding data. Polymerase chain reaction (RT-PCR) was then used to demonstrate mRNA for the subunits of nAChRs suggested by radioligand binding studies. Data obtained show that the human peripheral blood lymphocytes tested, expressed mRNAs for α4, α5, α7, β2 neuronal nAChRs subunits and β1 muscle nAChR subunit. Expression of the α5 mRNA subunit of nAChR was observed in the lymphocytes in each sample of lymphocytes tested. In contrast, the expression pattern of mRNAs for α4, α7, β1, and β2 mRNAs subunits of nAChRs, varied between individuals. Finally, Western blot analysis was used to confirm that mRNA expression resulted in the expression of protein for nAChR subunits in human peripheral lymphocytes using monoclonal antibodies against α4, α5, α7, and β2 nAChR subunits, which had been detected by RT-PCR. The results obtained from the Western blot analysis show that protein for α4, α5, and α7 nAChR subunits was expressed in most, but not all of the human peripheral blood lymphocyte samples tested and some of the bands obtained were faint. In contrast, protein for the β2 nAChR subunit was observed in a few samples tested and the bands were faint. From the results obtained in this study, it is possible to conclude that human peripheral blood lymphocytes may contain nAChRs with subunit compositions of α4β2, α4β2α5, and/or α7. However, further studies are necessary to show whether or not the single binding site for nicotine demonstrated by radioligand binding experiments is due to one or all of these nAChRs. Thus, the findings of the present study suggest the presence of nAChR on human peripheral blood lymphocytes. Nicotine and its effect may occur through these non- neuronal nAChRs mechanisms. Such a mechanism of action could account for the beneficial of nicotine in ulcerative colitis. Furthermore, a compound that acts on these receptors, but not on nAChRs found on other cells may have therapeutic utility in the treatment of inflammation.

Introdução: A grande variabilidade individual em resposta a fármacos antitabagismo sugere que tratamentos específicos podem ser mais efetivos em determinados subgrupos de fumantes. No contexto de medicina personalizada, o principal objetivo do presente estudo foi avaliar se polimorfismos nos genes CHRNA4, CHRNB2, CYP2B6 e ANKK1 estão associados com a resposta às terapias de cessação tabágica em pacientes provenientes de um programa de assistência ao fumante. Métodos: Estudo de coorte com 483 pacientes fumantes que receberam tratamento farmacológico (vareniclina, vareniclina e bupropiona, bupropiona em monoterapia ou coadministrada com terapia de reposição nicotínica). O sucesso na cessação tabágica foi considerado para os pacientes que completaram 6 meses de abstinência contínua. O teste de Fagerström para a dependência à nicotina (FTND) e o escore de consumo situacional Issa foram utilizados para avaliar a dependência à nicotina. Os polimorfismos CHRNA4 (rs1044396 e rs2236196), CHRNB2 (rs2072660 e rs2072661) e ANKK1 (rs1800497) foram genotipados pela análise da curva de melting e os polimorfismos CYP2B6 *9 (rs3745274), *4 (rs2279343), *5 (rs3211371) foram genotipados por restrição enzimática. Resultados: Os pacientes com o genótipo CC para o polimorfismo CHRNA4 (rs10443196) obtiveram menor taxa de sucesso no tratamento com vareniclina (29,5%) em comparação com os portadores dos genótipos CT ou TT (50,9%) (P=0,007; n=167). Os genótipos CT ou TT foram associados com maior odds ratio para o sucesso (OR=1,67; IC 95%=1,10-2,53; P=0,02), em um modelo multivariado. Os pacientes com o genótipo AA para o polimorfismo CYP2B6 (rs2279343) obtiveram maior taxa de sucesso no tratamento com bupropiona (48,0%) em comparação com portadores dos genótipos AG ou GG (35,5%) (P=0,05; n=237). O genótipo AA foi associado com maior odds ratio para o sucesso no tratamento (OR=1,92; IC 95%=1,08-3,42; P=0,03), em um modelo multivariado. Não foram observadas diferenças significativas nos escores FTND e Issa com relação aos polimorfismos estudados. Conclusão: Os polimorfismos CHRNA4 (rs1044396) e CYP2B6 (rs2279343) estão associados com a cessação tabágica em indivíduos tratados com vareniclina e bupropiona, respectivamente. Sugere-se que estes polimorfismos influenciam a resposta farmacológica e podem ser importantes para o desenho de uma farmacoterapia individualizada / Background: The large individual variability in response to drugs for smoking cessation suggests that specific treatments can be more effective in particular subgroups of smokers. In the context of personalized medicine, the main aim of the present study was to evaluate whether the CHRNA4, CHRNB2, CYP2B6 and ANKK1 polymorphisms are associated with response to smoking cessation therapies in patients from a smoker assistance program. Methods: This cohort study enrolled 483 smoking patients patients who received pharmacological treatment (varenicline, varenicline plus bupropion, bupropion in monoterapy or plus nicotine replacement therapy). Smoking cessation success was considered for patients who completed 6 months of continuous abstinence. Fagerström test for nicotine dependence (FTND) and Issa situational smoking scores were analyzed for nicotine dependence. The CHRNA4 (rs1044396 and rs2236196), CHRNB2 (rs2072660 and rs2072661) and ANKK1 rs1800497 polymorphisms were genotyped by high resolution melting analysis and the CYP2B6 *9 (rs3745274), *4 (rs2279343) and *5 (rs3211371) were genotyped by restriction fragment lenght polymorphisms. Results: Patients with CHRNA4 rs1044396 CC genotype had lower success rate in treatment with varenicline (29.5%) compared with carriers of CT or TT genotypes (50.9%) (P=0.007, n=167). The CT or TT genotypes were associated with higher odds ratio for success (OR=1.67, 95%CI=1.10-2.53, P=0.02), in a multivariate model. Patients with CYP2B6 rs2279343 AA genotype had higher success rate in treatment with bupropion (48.0%) compared with carriers of AG or GG genotypes (35.5%) (P=0.05, n=237). The AA genotype was associated with higher odds ratio for success (OR=1.92, 95%CI=1.08-3.42, P=0.03), in a multivariate model. We did not observe significant differences in the FTND and Issa scores according to the studied polymorphisms. Conclusion: The CHRNA4 rs1044396 and CYP2B6 rs2279343 are associated with smoking cessation in individuals on varenicline and bupropion terapies, respectively. We suggest that these polymorphisms influence the pharmacological response of these drugs and it might be important in the design of individualized pharmacotherapy