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Peptídeos antimicrobianos da hemolinfa do escorpião: Tityus serrulatus. / Antimicrobial peptides from the hemolymph of the scorpion: Tityus serrulatus.Oliveira, Thiago de Jesus 05 October 2016 (has links)
Em artrópodes o sistema imune inato contribui para a adaptação de animais como os escorpiões à diferentes ambientes. Esse sistema é composto por mecanismos capazes de agir contra injúrias e a ação de microrganismos e entre esses mecanismos estão os peptídeos antimicrobianos (PAMs). O objetivo deste trabalho foi identificar PAMs presentes na hemolinfa de Tityus serrulatus. Para isso sua hemolinfa foi extraída e separados os hemócitos e plasma, em seguida fracionamos em 3 concentrações de acetonitrila em TFA 0,05% (05, 40 e 80%). Estas frações foram submetidas a uma cromatografia liquida de alta eficiência (CLAE) e os picos foram avaliados quanto a sua ação antimicrobiana e hemolítica. Foram identificadas 16 frações que apresentam atividade antimicrobiana. Uma das frações com atividade antimicrobiana, presente nos hemócitos apresentou similaridade com defensina descrita em carrapatos da espécie Ixodes scapularis. Essa fração possui aproximadamente 3486 Da, não apresenta atividade hemolítica e foi denominada como Serrulina. / In arthropods, its innate immune system contributes to the adaptation of animals like scorpions to different environments. This system consists of mechanisms that act avoiding injuries and against the action of microorganisms, among these mechanisms are antimicrobial peptides (AMPs). The aim of this study was to identify AMPs, present in the hemolymph of Tityus serrulatus. The hemolymph was extracted and then we separated hemocyte and plasma. The samples were fractionated in different concentrations of acetonitrile in TFA 0.05% (05, 40 and 80%). These fractions were subjected to high-performance liquid chromatography (HPLC) and the peaks obtained were evaluated for its antimicrobial and hemolytic action. We found sixteen fractions with antimicrobial activity. One of the fractions with antimicrobial activity, present in hemocytes, is similar with a defensin described in ticks, Ixodes scapularis. This fraction has about 3486 Da, has no hemolytic activity and was named as Serrulina.
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Peptídeos antimicrobianos da hemolinfa do escorpião: Tityus serrulatus. / Antimicrobial peptides from the hemolymph of the scorpion: Tityus serrulatus.Thiago de Jesus Oliveira 05 October 2016 (has links)
Em artrópodes o sistema imune inato contribui para a adaptação de animais como os escorpiões à diferentes ambientes. Esse sistema é composto por mecanismos capazes de agir contra injúrias e a ação de microrganismos e entre esses mecanismos estão os peptídeos antimicrobianos (PAMs). O objetivo deste trabalho foi identificar PAMs presentes na hemolinfa de Tityus serrulatus. Para isso sua hemolinfa foi extraída e separados os hemócitos e plasma, em seguida fracionamos em 3 concentrações de acetonitrila em TFA 0,05% (05, 40 e 80%). Estas frações foram submetidas a uma cromatografia liquida de alta eficiência (CLAE) e os picos foram avaliados quanto a sua ação antimicrobiana e hemolítica. Foram identificadas 16 frações que apresentam atividade antimicrobiana. Uma das frações com atividade antimicrobiana, presente nos hemócitos apresentou similaridade com defensina descrita em carrapatos da espécie Ixodes scapularis. Essa fração possui aproximadamente 3486 Da, não apresenta atividade hemolítica e foi denominada como Serrulina. / In arthropods, its innate immune system contributes to the adaptation of animals like scorpions to different environments. This system consists of mechanisms that act avoiding injuries and against the action of microorganisms, among these mechanisms are antimicrobial peptides (AMPs). The aim of this study was to identify AMPs, present in the hemolymph of Tityus serrulatus. The hemolymph was extracted and then we separated hemocyte and plasma. The samples were fractionated in different concentrations of acetonitrile in TFA 0.05% (05, 40 and 80%). These fractions were subjected to high-performance liquid chromatography (HPLC) and the peaks obtained were evaluated for its antimicrobial and hemolytic action. We found sixteen fractions with antimicrobial activity. One of the fractions with antimicrobial activity, present in hemocytes, is similar with a defensin described in ticks, Ixodes scapularis. This fraction has about 3486 Da, has no hemolytic activity and was named as Serrulina.
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Moléculas biotivas do veneno da aranha migalomorfa Avicularia juruensis. / Bioactive molecules from the venom of mygalomorph spider Avicularia juruensis.Nascimento, Soraia Maria do 21 September 2016 (has links)
Venenos de aranhas podem ser boas fontes de moléculas com potencial terapêutico e biotecnológico. Sendo assim, esse estudo teve como objetivo analisar moléculas bioativas do veneno de Avicularia juruensis, com foco em PAMs e enzimas. O veneno foi extraído por estimulação elétrica e, através de CLAE-FR, ensaio de inibição do crescimento microbiano e LC-MS/MS, foram identificados e caracterizados 7 PAMs. Todos possuem o motivo nó de cistina do tipo ICK e têm similaridade com neurotoxinas de venenos de outras aranhas. O perfil eletroforético do veneno de A. juruensis indicou que ele possui moléculas com massa entre 130 e abaixo de 10 kDa. Utilizando LC-MS/MS e análise transcriptômica foi possível identificar 6 metaloproteinases. Elas possuem domínios conservados de proteínas do tipo ADAMs, MMPs e metalopeptidases astacina-like. A presença destas enzimas é, provavelmente, importante para a digestão extracorpórea, visto que esta aranha geralmente consome pequenas aves. O estudo de venenos de aranhas terafosídeas é essencial, visto que este é um grupo pouco estudado. / Spider venoms can be good sources of molecules with therapeutic and biotechnological potential. Thus, this study aimed to analyze bioactive molecules from venom of Avicularia juruensis, focusing on AMPs and enzymes. The venom was extracted by electrical stimulation. By RP-HPLC, liquid growth inhibition assay and LC-MS/MS, seven AMPs were identified and characterized. All these peptides have inhibitory cystine knot motif and they showed similarity with venom neurotoxins from others spiders. The electrophoretic profile of A. juruensis venom shows that it has molecules with molecular masses between 130 kDa and below 10 kDa. By LC-MS/MS and transcriptomic analysis yielded the identification of six metalloproteinases, which possess typical conserved domains from ADAMs, MMPs and astacin-like metallopeptidases. These metalloproteinases may be involved in a key role during preoral digestion. The study of Theraphosidae spider venom is essential, since this group is poorly studied.
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Identification et caractérisations physico-chimiques et pharmacologiques de nouvelles molécules bioactives isolées à partir de venins d’animaux : exemple des peptides antimicrobiens / Identification, physicochemical and pharmacological characterisation of new bioactive molecules isolated from animals venoms : example of antimicrobial peptidesMollet, Chloé 20 October 2017 (has links)
La recherche de nouvelles molécules bioactives utilisables en thérapeutique est un enjeu majeur de santé publique en particulier dans le traitement de certaines maladies telle que les infections bactériennes.La résistance naturelle des bactéries et la surutilisation des antibiotiques ont entraîné la sélection de bactéries pathogènes résistantes à de multiples médicaments. Depuis les dernières décennies, la résistance aux antibiotiques conventionnels a limité les options thérapeutiques, entraînant une augmentation significative de la mortalité et de la morbidité dans les hôpitaux. En outre, depuis 1970, seules deux nouvelles classes d'antibiotiques ont été mises sur le marché. Les venins constituent une source riche de substances naturelles pharmacologiquement actives uniques et novatrices, tels que les peptides antimicrobiens (PAMs) qui représentent une alternative originale pour remédier à ce problème de santé publique.Dans notre étude, parmi les 200 venins d’animaux étudiés pour leurs propriétés antibactériennes, au moins six PAMs ont été isolés à partir d’un venin d’insecte. Le peptide 1 original inhibe la croissance des bactéries Gram positives et négatives mais présente une forte hémotoxicité (IT = 1,6-3,2). La synthèse en phase solide d’analogues structuraux a permis d’identifier R1W8 et I1N11, moins toxiques (IT = 18 et >800 respectivement). Les résultats préliminaires de l’étude du mécanisme d’action suggèrent que ces peptides agissent contre les bactéries par perméabilisation de leur membrane cytoplasmique. Ces peptides peuvent servir de modèles pour l’élaboration de nouveaux agents antimicrobiens. / The research for new bioactive molecules which can be used in therapeutic is a major public health issue, particularly in the treatment of certain diseases such as bacterial infections.The natural resistance of bacteria consecutive to overuse of antibiotics have resulted in the selection of pathogenic multi-drug resistant bacteria. Over the last few decades, resistance to conventional antibiotics has limited treatment options, resulting in a significant increase in mortality and morbidity in hospitals. Moreover, since 1970, only two new classes of antibiotics have been placed on the market. Venoms are known to be a rich source of unique and innovative pharmacologically active substances, such as antimicrobial peptides (PAMs), which represent an original alternative to small molecules for the development of new active and non-resistance inducing antibiotics.In our study, among the 200 venoms of animals studied for their antibacterial properties, at least six PAMs were isolated from an insect venom. The original peptide 1 inhibits the growth of Gram positive and negative bacteria but shows a high hemotoxicity (TI = 1,6-3,2). The solid phase synthesis of structural analogs allowed to identify R1W8 and I1N11, less toxic (TI = 18 et >800 respectively). The preliminary results of the action mechanism study suggest that these peptides have a pore-forming action on bacteria cytoplasmic membrane. These peptides can be used as models for the development of new antimicrobial agents.
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Signaling Mechanisms Behind the Benefits of SleepSinner, Marina Patricia 31 January 2023 (has links)
Hintergrund: Schlaf ist ein streng regulierter Zustand körperlicher Ruhe und reduzierten Bewusstseins, der evolutionär im ganzen Tierreich konserviert ist. Schlafmangel ist in der modernen Gesellschaft weit verbreitet und betrifft 10 – 30 % der Erwachsenen. Dies stellt ein ernstes gesundheitliches Problem dar, da Schlafmangel mit vielen Krankheiten assoziiert ist, darunter Depressionen, Krebs und Herz-Kreislauf-Erkrankungen. Umgekehrt beeinflussen auch Krankheiten und das Immunsystem das Schlafverhalten. Trotz der fundamentalen Rolle dieser Wechselbeziehung sind grundlegende molekulare Mechanismen, die Funktionen des Immunsystems und Schlafkontrolle verbinden, bisher kaum verstanden. Da die Schlafregulation in Säugetieren sehr komplex ist, ist es sinnvoll konservierte Mechanismen zuerst in einfacheren Modellorganismen zu untersuchen. Der Rundwurm C. elegans ist ein solcher etablierter, simpler und vielseitiger Modellorganismus für die Schlafforschung. Er schläft sowohl im Rhythmus seiner Larvenentwicklung immer jeweils während des Lethargus kurz vor der Häutung, als auch nach besonderem Stress, wie zum Beispiel Hunger oder Hitze. C. elegans besitzt ein invariantes Nervensystem, in dem eine rapide Depolarisation des einzelnen RIS-Interneurons genügt, um Schlaf zu induzieren. Eine Mutation des AP2 Transkriptionsfaktors APTF-1 verhindert die Expression von FLP-11, dem schlafinduzierenden Neuropeptid von RIS. Dies führt praktisch zu völliger Schlaflosigkeit, die in C. elegans in der Regel nicht tödlich ist, und deshalb ein nützliches Modell für genetisch-chronischen Schlafmangel darstellt. Unser Labor fand heraus, dass eine Gain-of-function-Mutation in der Kollagenase NAS-38 über Signalwege der angeborenen Immunität und RIS-Aktivierung zu vermehrtem Schlaf während des Lethargus führt. Gleichzeitig wird dabei die Expression einer ganzen Familie antimikrobieller Peptide (AMP) hochreguliert. Derselbe Signalweg, einschließlich der AMP, sowie das Schlafverhalten werden auch durch Verletzungen induziert. Interessanterweise sterben nicht-schlafende Würmer nach einer Verletzung häufiger. Insgesamt deutet dies darauf hin, dass AMP als Signalmoleküle fungieren könnten, die Schlaf als Teil einer globalen Schutzreaktion vom peripheren Gewebe zum Nervensystem signalisieren. Für diese Hypothese fehlten bisher jedoch die Beweise. Fragestellungen und Hypothesen: Mein Ziel war es, den molekularen Mechanismus zu entschlüsseln, durch den verschiedene Reize der angeborenen Immunität, das heißt NAS-38 sowie epidermale Verletzungen, Schlaf induzieren. Zwei Fragen habe ich hierbei im Speziellen adressiert: Welche Domänen des NAS 38-Proteins sind an der Schlafregulation beteiligt? Da die Astacin-Domäne als aktive Proteasedomäne von NAS-38 angesehen wird, erwartete ich eine Schlüsselrolle dieser Domäne auch in der Schlafinduktion. Zweitens, welche Rolle spielen AMP bei der Signalisierung von immunitätsinduziertem Schlaf? Da gezeigt wurde, dass AMP während des NAS-38 Schlafes und auch nach Verwundung hochreguliert sind, erwartete ich, dass AMP an der Signalisierung von Schlaf von der Epidermis zum Nervensystem beteiligt sind. In einem zweiten Schritt untersuchte ich die molekularen Mechanismen, die den Vorteilen von Schlaf für das Überleben von Verletzungen zugrunde liegen. Auch hier habe ich speziell zwei Fragestellungen untersucht: Verändert genetischer Schlafentzug die transkriptionelle Reaktion auf epidermale Verletzungen? Da Schlaf für viele fundamentale Prozesse wichtig ist und Schlaflosigkeit die Sterblichkeit nach Verletzungen erhöht, vermutete ich, dass genetischer Schlafentzug die transkriptionelle Reaktion auf Verletzungen beeinträchtigt. Zweitens, ist Schlaf wichtig für die Entwicklung von Robustheit, um im Falle einer Verletzung weniger Schaden zu nehmen? Während der Larvenentwicklung fällt die Cuticula-Synthese mit Schlaf zeitlich zusammen. Daher stellte ich die Hypothese auf, dass Schlafentzug die korrekte Bildung einer Cuticula beeinträchtigt. Methoden: Zur Analyse der Signalmechanismen, durch die sowohl NAS-38 als auch Verletzungen Schlaf induzieren, filmte ich das Schlafverhalten von C. elegans mittels Langzeit-Bildgebung in Agarose-Mikrokammern. So führte ich eine Struktur-Funktions-Analyse mit verschiedenen nas-38 Mutanten durch, in denen jeweils eine andere NAS-38 Domäne deletiert war. Darüber hinaus testete ich verschiedene Suppressoren für immunvermittelten Schlaf, der durch NAS 38 oder Verletzungen induziert war. Die Redundanz des Suppressionseffektes der verschiedenen Mitglieder der AMP-Familie auf immunvermittelten Schlaf testete ich, indem ich den Suppressionsphänotyp einer CRISPR/Cas9-editierten Multi-Knockout-Mutante analysierte, in der insgesamt 19 AMP deletiert waren. Um Effektoren zu identifizieren, die den AMP nachgeschaltet sind, induzierte ich Schlaf durch Überexpression des AMP NLP 29 unter der Kontrolle eines Hitzeschock-Promotors und analysierte die Sschlafsuppression durch verschiedene Knockout-Mutanten. Im zweiten Projekt beschäftigte ich mich mit der Frage, wie genau Schlaf das Überleben nach Verletzungen unterstützt. Ich verglich die Expression von literaturbekannten Reportern für verschiedene Aspekte der Verwundungsreaktion mittels Langzeit-Fluoreszenzmikroskopie im Wildtyp sowie dem Modell für chronisch-genetischen Schlafmangel. Darüber hinaus habe ich die Transkriptome zwischen jeweils adulten verwundeten und unverwundeten Wildtypen und schlaflosen Mutanten verglichen. Um die Struktur der Cuticula des Wildtyps und der schlaflosen Mutante zu vergleichen, analysierte ich außerdem rasterelektronen-mikroskopische Aufnahmen. Ergebnisse: Im ersten Projekt konnte ich zeigen, dass NAS-38 Schlaf durch seine Astacin-Domäne verlängert. Dieser Prozess wird moderiert durch die TSP-1-Domäne. Weiterhin konnte ich zeigen, dass viele AMP redundant wirken um immunvermittelten Schlaf, verursacht durch NAS-38 oder Verletzungen, zu signalisieren. Ich konnte zeigen, dass das AMP NLP-29 über den Neuropeptidrezeptor NPR-12 wirkt. Dieser kann NLP-29-induzierten Schlaf vermitteln, wenn er in einem neuronalen Netzwerk exprimiert wird, welches nachweislich RIS aktiviert. Interessanterweise fand ich außerdem heraus, dass für NLP-29-vermittelten Schlaf der EGFR Signalweg notwendig ist. Im zweiten Projekt entdeckte ich, dass Schlaflosigkeit die transkriptionelle Reaktion auf Verletzungen nicht dramatisch verändert. Allerdings ist das Transkriptionsprofil bereits in der unverletzten schlaflosen Mutante verändert. Dies betraf unter anderem eine Gruppe oszillierender Gene, die Cuticula-assoziierte Proteine codieren, und deren Expression normalerweise ihren Höhepunkt gegen Ende des Lethargus erreicht. Da angenommen wird, dass der Zeitpunkt der Kollagenexpression entscheidend für eine fehlerfreie Cuticula-Bildung ist, analysierte ich die Cuticula der schlaflosen Mutante. Ich konnte zeigen, dass die Cuticula des adulten Tieres tatsächlich einen strukturellen Defekt aufweist. Dieser betrifft speziell Furchen in der Region nahe den Alae und könnte möglicherweise die Strapazierfähigkeit der Cuticula gegenüber bestimmten Belastungen verringern. Daher könnte Schlaf erforderlich sein, Robustheit in Form einer strukturierten Cuticula zu fördern. Schlussfolgerungen: In diesem Dissertationsprojekt vollendete ich die Charakterisierung eines neuentdeckten Mechanismus in C. elegans, durch den Verwundungen Schlaf als Teil der Immunantwort aus der Peripherie zum Nervensystem signalisieren. Ich konnte zeigen, dass AMP gewebeübergreifend Signale von der Epidermis an ein neuronales Netz vermitteln, welches wiederum RIS aktiviert und dadurch Schlaf induziert. Da Komponenten dieses Signalweges konserviert sind, könnten AMP auch in anderen Tieren, einschließlich des Menschen, Schlaf zur Genesung fördern. Darüber hinaus habe ich die Grundlagen für die Analyse molekularer Mechanismen geschaffen, die den essentiellen Funktionen des Schlafes für Heilung und Überleben zugrunde liegen. Obwohl Schlaflosigkeit die transkriptionelle Reaktion auf Verletzungen nicht drastisch zu verändern scheint, deuten meine Ergebnisse auf eine Rolle des Schlafes bei der richtigen Cuticula-Bildung und möglicherweise sogar auf eine vielfältigere Rolle bei der zeitlichen Regulierung der Genexpression hin.:Summary I
Zusammenfassung IV
Contents VII
List of Figures XII
List of Tables XIV
Abbreviations XV
1. Introduction 1
1.1. Sleep is fascinating 1
1.1.1. The origin and basic features of sleep 1
1.1.2. Regulation of sleep in higher animals 3
1.1.2.1. Neuronal control of sleep 3
1.1.2.2. Molecular control of sleep 5
1.1.3. The functions of sleep 6
1.2. The immune system and its relationship to sleep 7
1.3. Wound healing and its relationship to sleep 10
1.4. Caenorhabditis elegans is a well-studied model organism 12
1.4.1. Sleep in C. elegans 15
1.4.2. The C. elegans cuticle 18
1.4.3. Immunity in C. elegans 19
1.4.4. Wound healing response in C. elegans 22
2. Previous results 25
2.1. A strong gain-of-function mutation in the astacin metallo-proteinase NAS 38 increases lethargus duration and movement quiescence in C. elegans 25
2.2. NAS-38 increases sleep mostly through the RIS neuron 25
2.3. NAS-38 is expressed in the epidermis and oscillates with the developmental rhythm 25
2.4. nas-38(ok3407) acts via innate immunity pathways to increase lethargus duration and AMP expression 27
2.5. Overexpression of AMPs induces RIS dependent quiescence 30
2.6. Epidermal wounding induces RIS-dependent sleep, which is beneficial for survival 31
3. Thesis Aims 34
3.1. Aim 1 – Characterizing the molecular mechanism through which NAS-38, innate immunity, and wounding induce sleep 34
3.2. Aim 2 – Analyzing how sleep promotes survival after wounding 35
4. Materials and Methods 36
4.1. C. elegans maintenance 36
4.2. C. elegans crossing and genotyping 41
4.3. Creation of transgenic animals 45
4.3.1. Creating the npr-12 rescue in nmr-1 expressing neurons 45
4.3.2. Microparticle bombardment 45
4.3.3. CRISPR/Cas9 system 46
4.4. Synchronizing worm cultures by hypochlorite treatment 48
4.5. Imaging 49
4.5.1. Imaging setups 49
4.5.2. DIC Imaging of worm development, lethargus, and sleep behavior 50
4.5.2.1. Imaging of heterozygous mutants 50
4.5.3. DIC imaging in the temperature control device 51
4.5.4. Fluorescent imaging experiments 51
4.5.4.1. nas-38p::d1GFP and nlp-29p::GFP during L1 development 51
4.5.4.2. nlp-29p::GFP in L4 larvae 52
4.5.4.3. nlp-29p::GFP after heat shock-induced lin-3 overexpression 52
4.5.4.4. Imaging fluorescent markers in (wounded) young adults 52
4.5.4.5. Functional Ca2+ imaging in young adults 52
4.5.4.6. Fluorescence imaging across the whole developmental time 54
4.5.4.7. Nuclear decompaction assays 55
4.5.4.8. Transcription factor localization with spinning disc confocal microscopy 55
4.5.4.9. Imaging DPY-13::mKate2 in young adults 56
4.6. Image analysis 56
4.6.1. Assessment of developmental time and lethargus detection 56
4.6.2. Sleep detection in DIC mode 56
4.6.3. Analyzing functional Ca2+ images 57
4.6.4. Fluorescent reporter analysis during long-term imaging 57
4.7. RNAi-by-feeding 58
4.8. Transcriptome analysis 59
4.8.1. Analysis of the nas-38(ok3407) transcriptome 59
4.8.2. Analysis of the wounding transcriptome 59
4.9. Epidermal wounding 62
4.9.1. Laser wounding 62
4.9.2. Needle wounding 62
4.9.3. Survival assay 63
4.10. Scanning Electron Microscopy (SEM) 63
4.11. Histamine-inducible hyperpolarization of RIS 64
4.12. Cuticle integrity test with Sodium hypochlorite 64
4.13. NPR-12 receptor modeling 64
4.14. Quantification and statistical analysis 65
5. Results 66
5.1. Aim 1 – Characterizing the pathway through which NAS 38, wounding and innate immunity induce sleep 66
5.1.1. The loss of function mutation nas-38(tm2655) shows the opposite phenotype to the gain of function mutation nas-38(ok3407) 66
5.1.2. nas-38 gain-of-function mutants act through their astacin protease domain and are semi-dominant 66
5.1.3. Transcriptome analysis of nas-38(ok3407) reveals upregulation of genes associated with secretion, innate immunity and cuticle formation 69
5.1.4. nas-38(knu568) increased movement quiescence can be suppressed by mutations of innate immunity pathways 72
5.1.5. Multiple NLPs and CNCs act in parallel to mediate nas-38(ok3407) induced sleep 75
5.1.6. Wounding-induced sleep requires RIS, ALA, EGFR and immune signaling 77
5.1.7. NLP-29 signals via the NPR-12 receptor in neurons upstream of RIS 80
5.1.8. NLP-29 requires neuronal EGFR signaling to induce sleep 81
5.1.9. Simple in silico models suggest that many different NLPs can bind to NPR-12 83
5.1.10. AMPs contribute to the survival after wounding 85
5.2. Aim 2 – Identifying the advantages sleep provides that help to survive harmful conditions 87
5.2.1. Wounding decreases the lifespan in the wild type and the aptf 1(gk794) mutant 87
5.2.2. Histamine-inducible RIS hyperpolarization suppresses wounding sleep 87
5.2.3. Genetic sleep deprivation decreases translocation of DAF-16 into the nucleus immediately after wounding 89
5.2.4. Genetic sleep deprivation hardly changes the transcriptional wounding response 95
5.2.5. Genetic sleep deprivation and wounding increase nuclear PHA 4 101
5.2.6. Oscillating genes and genes associated with the cuticle and the unfolded protein response are upregulated in young adult aptf 1(gk794) mutants 106
5.2.7. Genetic sleep deprivation leads to a malformation of cuticular furrows 109
5.2.8. Genetic sleep deprivation leads to an increased transcription of lethargus specific oscillating genes in young adults 114
5.2.9. Genetic sleep deprivation does not significantly affect development time or body size 120
5.2.10. Expression of fluorescent reporters of oscillating genes is not phase-shifted in the aptf-1(gk794) mutant 122
6. Discussion and Outlook 128
6.1. NAS-38 acts through its astacin domain to increase sleep via innate immunity pathways 128
6.2. NAS-38 during larval lethargus and epidermal wounding in the adult signal sleep via many AMPs as part of a peripheral immune response 130
6.3. Epidermal AMPs activate a neuronal circuit to induce sleep 131
6.4. Genetically sleep deprived worms can mount a proper wounding response in many ways, except for DAF-16/FOXO regulation 132
6.5. Genetic sleep deprivation alters cuticle formation 135
6.6. The role of PHA-4/FOXA in genetically sleep-deprived animals 137
6.7. Conclusion 139
7. References 140
8. Acknowledgements 163
9. Appendix 166
9.1. Standard reagents 166
9.2. Sequence summary of PHX3754 167
9.3. MATLAB script to analyze the intensity of fluorescent reporters over time 171
9.4. Permissions to reprint figures 174
9.5. Experimental author contributions 175
9.6. Predicted interactions between the NPR-12 receptor and peptides of the nlp and cnc families 176
9.7. Overlap of the adult wounding transcriptome with other data sets 179
9.8. Curriculum Vitae – Marina Patricia Sinner 181 / Background: Sleep is a tightly regulated state of behavioral quiescence and reduced consciousness, which is conserved throughout the animal kingdom. In modern societies 10 – 30 % of the adult population suffer from insufficient sleep, which poses a serious health problem as sleep deprivation is associated with a variety of diseases including depression, cancer, and cardiovascular diseases. Conversely, sickness and the immune system also influence sleep patterns. Despite the important role of this interrelationship between sleep and immunity, basic molecular mechanisms that link both vital functions are only poorly understood yet. As sleep regulation is complex in mammals and is thus difficult to address experimentally, it is reasonable to investigate its basic conserved mechanisms in simpler models first. The nematode C. elegans is such a well-established, simple, and powerful model organism for sleep research. It displays stress-induced sleep, for example upon starvation or heat shock, but also developmentally-timed sleep during lethargus prior to each larval molt. C. elegans possesses an invariant nervous system in which rapid depolarization of the single RIS interneuron is sufficient to induce sleep. Mutation of the AP2 transcription factor APTF 1 deprives RIS of its sleep-inducing neuropeptide FLP-11 and thus virtually abolishes sleep. This is not per se lethal in C. elegans, thereby presenting a powerful model for genetic sleep deprivation. Our lab found that a gain-of-function mutation in the collagenase NAS-38 strongly increases RIS-dependent sleep during lethargus with a concomitant upregulation of a large family of antimicrobial peptides (AMPs) via immunity pathways. Epidermal wounding also triggers AMP expression via immune signaling and induces sleep in the adult worm. Moreover, genetic sleep deprivation increases mortality upon epidermal injury. Together, this suggests AMPs to act as somnogens from peripheral tissues to the nervous system as part of a protective response. This hypothesis, however, was hitherto lacking final evidence and pathway components.
Research questions and hypotheses: I aimed to characterize the molecular mechanism by which separate triggers of innate immunity, i. e. NAS-38 and wounding, induce sleep. I specifically addressed two questions: Firstly, which domains of the NAS-38 protein are involved in sleep regulation? As the astacin domain is predicted to be the active protease domain of NAS-38, I expected a role for it also in sleep induction by NAS-38. Secondly, what is the role of AMPs in signaling immunity-induced sleep? As they have been shown to be upregulated during times of increased sleep in the nas-38 mutant and after wounding, I expected AMPs to be involved in signaling sleep from the epidermis to the nervous system. In a second step, I investigated the molecular mechanisms underlying the benefits of sleep for surviving injury. Again, I addressed two questions: Firstly, does genetic sleep deprivation alter the transcriptional wounding response? As sleep has a role in many fundamental processes and sleeplessness increases mortality upon wounding, I hypothesized that genetic sleep deprivation impairs wounding-induced changes of transcriptional activity. Secondly, does sleep help building robustness before encountering injury? During larval development the synthesis of a new cuticle coincides with sleep. Thus, I hypothesized that genetic sleep deprivation impairs proper cuticle formation. Methods: To dissect the signaling mechanisms by which NAS-38 and wounding induced sleep, I followed sleep behavior of C. elegans by long-term imaging in agarose microchambers. I performed a structure-function analysis with different nas-38 mutants, each carrying a deletion of a different domain. Moreover, I screened for suppressors of sleep induced by NAS 38 or wounding. To test for redundancy of the AMP family, I investigated the suppression-phenotype of a CRISPR/Cas9 edited multi-knockout mutant lacking 19 AMPs. To identify downstream effectors of the AMP NLP 29, I induced sleep by overexpressing NLP 29 from a heat-shock promoter and analyzed the suppression-phenotype of different knockout mutants. For the second project, I addressed the question how sleep aids recovery from injury. I followed fluorescent reporters of previously described wounding response pathways by fluorescent long-term imaging in wild-type and genetically sleep-deprived animals. Moreover, I compared the transcriptomes of adult wild-type and genetically sleep-deprived worms both wounded and unwounded. To investigate the structure of the cuticle, I analyzed scanning electron microscopy images. Results: In the first project, I could show that NAS-38 indeed increases sleep via its astacin domain in a process that is modulated by the TSP-1 domain. Moreover, I could show that many AMPs act redundantly in mediating immunity-induced sleep downstream of NAS-38 and after wounding. I demonstrated that the AMP NLP-29 signals sleep via the neuropeptide receptor NPR 12. This receptor can mediate sleep when it is specifically expressed in command interneurons of a circuit that has been shown to activate RIS. Interestingly, I also found that EGFR signaling is required to mediate NLP-29-induced sleep.
In the second project, I found that sleeplessness does not dramatically alter the transcriptional wounding response. However, I could show that transcription is altered already in the unwounded non-sleeping mutant. This affects, among others, a specific subset of oscillating collagen-coding genes, whose expression usually peaks around the end of lethargus. As the timing of expression of collagens is thought to be highly important for proper cuticle formation, I characterized the cuticle of the aptf-1(gk794) mutant. I could show that young adult aptf 1(gk794) worms indeed have a structural defect affecting cuticular furrows in the region adjacent to the alae, which could potentially decrease specific aspects of resilience of the cuticle. Thus, sleep might be required to build robustness in the form of a properly structured cuticle. Conclusion: In this PhD project, I completed the characterization of a novel mechanism by which wounding signals sleep from the periphery to the nervous system as part of the immune response in C. elegans. I could show that AMPs act as cross-tissue signals from the epidermis to a neuronal RIS-controlling circuit that ultimately leads to sleep induction. As components of this molecular pathway are highly conserved, AMPs might also induce sleep to promote recovery from injury in other organisms, including humans. Moreover, I laid the foundations for dissecting the molecular mechanisms behind the functions of sleep for healing and survival. Even though the disability to sleep did not seem to drastically change the transcriptional response to wounding, my results indicate a role for sleep in proper cuticle formation in C. elegans and potentially even a broader role in the regulation of precise gene expression timing.:Summary I
Zusammenfassung IV
Contents VII
List of Figures XII
List of Tables XIV
Abbreviations XV
1. Introduction 1
1.1. Sleep is fascinating 1
1.1.1. The origin and basic features of sleep 1
1.1.2. Regulation of sleep in higher animals 3
1.1.2.1. Neuronal control of sleep 3
1.1.2.2. Molecular control of sleep 5
1.1.3. The functions of sleep 6
1.2. The immune system and its relationship to sleep 7
1.3. Wound healing and its relationship to sleep 10
1.4. Caenorhabditis elegans is a well-studied model organism 12
1.4.1. Sleep in C. elegans 15
1.4.2. The C. elegans cuticle 18
1.4.3. Immunity in C. elegans 19
1.4.4. Wound healing response in C. elegans 22
2. Previous results 25
2.1. A strong gain-of-function mutation in the astacin metallo-proteinase NAS 38 increases lethargus duration and movement quiescence in C. elegans 25
2.2. NAS-38 increases sleep mostly through the RIS neuron 25
2.3. NAS-38 is expressed in the epidermis and oscillates with the developmental rhythm 25
2.4. nas-38(ok3407) acts via innate immunity pathways to increase lethargus duration and AMP expression 27
2.5. Overexpression of AMPs induces RIS dependent quiescence 30
2.6. Epidermal wounding induces RIS-dependent sleep, which is beneficial for survival 31
3. Thesis Aims 34
3.1. Aim 1 – Characterizing the molecular mechanism through which NAS-38, innate immunity, and wounding induce sleep 34
3.2. Aim 2 – Analyzing how sleep promotes survival after wounding 35
4. Materials and Methods 36
4.1. C. elegans maintenance 36
4.2. C. elegans crossing and genotyping 41
4.3. Creation of transgenic animals 45
4.3.1. Creating the npr-12 rescue in nmr-1 expressing neurons 45
4.3.2. Microparticle bombardment 45
4.3.3. CRISPR/Cas9 system 46
4.4. Synchronizing worm cultures by hypochlorite treatment 48
4.5. Imaging 49
4.5.1. Imaging setups 49
4.5.2. DIC Imaging of worm development, lethargus, and sleep behavior 50
4.5.2.1. Imaging of heterozygous mutants 50
4.5.3. DIC imaging in the temperature control device 51
4.5.4. Fluorescent imaging experiments 51
4.5.4.1. nas-38p::d1GFP and nlp-29p::GFP during L1 development 51
4.5.4.2. nlp-29p::GFP in L4 larvae 52
4.5.4.3. nlp-29p::GFP after heat shock-induced lin-3 overexpression 52
4.5.4.4. Imaging fluorescent markers in (wounded) young adults 52
4.5.4.5. Functional Ca2+ imaging in young adults 52
4.5.4.6. Fluorescence imaging across the whole developmental time 54
4.5.4.7. Nuclear decompaction assays 55
4.5.4.8. Transcription factor localization with spinning disc confocal microscopy 55
4.5.4.9. Imaging DPY-13::mKate2 in young adults 56
4.6. Image analysis 56
4.6.1. Assessment of developmental time and lethargus detection 56
4.6.2. Sleep detection in DIC mode 56
4.6.3. Analyzing functional Ca2+ images 57
4.6.4. Fluorescent reporter analysis during long-term imaging 57
4.7. RNAi-by-feeding 58
4.8. Transcriptome analysis 59
4.8.1. Analysis of the nas-38(ok3407) transcriptome 59
4.8.2. Analysis of the wounding transcriptome 59
4.9. Epidermal wounding 62
4.9.1. Laser wounding 62
4.9.2. Needle wounding 62
4.9.3. Survival assay 63
4.10. Scanning Electron Microscopy (SEM) 63
4.11. Histamine-inducible hyperpolarization of RIS 64
4.12. Cuticle integrity test with Sodium hypochlorite 64
4.13. NPR-12 receptor modeling 64
4.14. Quantification and statistical analysis 65
5. Results 66
5.1. Aim 1 – Characterizing the pathway through which NAS 38, wounding and innate immunity induce sleep 66
5.1.1. The loss of function mutation nas-38(tm2655) shows the opposite phenotype to the gain of function mutation nas-38(ok3407) 66
5.1.2. nas-38 gain-of-function mutants act through their astacin protease domain and are semi-dominant 66
5.1.3. Transcriptome analysis of nas-38(ok3407) reveals upregulation of genes associated with secretion, innate immunity and cuticle formation 69
5.1.4. nas-38(knu568) increased movement quiescence can be suppressed by mutations of innate immunity pathways 72
5.1.5. Multiple NLPs and CNCs act in parallel to mediate nas-38(ok3407) induced sleep 75
5.1.6. Wounding-induced sleep requires RIS, ALA, EGFR and immune signaling 77
5.1.7. NLP-29 signals via the NPR-12 receptor in neurons upstream of RIS 80
5.1.8. NLP-29 requires neuronal EGFR signaling to induce sleep 81
5.1.9. Simple in silico models suggest that many different NLPs can bind to NPR-12 83
5.1.10. AMPs contribute to the survival after wounding 85
5.2. Aim 2 – Identifying the advantages sleep provides that help to survive harmful conditions 87
5.2.1. Wounding decreases the lifespan in the wild type and the aptf 1(gk794) mutant 87
5.2.2. Histamine-inducible RIS hyperpolarization suppresses wounding sleep 87
5.2.3. Genetic sleep deprivation decreases translocation of DAF-16 into the nucleus immediately after wounding 89
5.2.4. Genetic sleep deprivation hardly changes the transcriptional wounding response 95
5.2.5. Genetic sleep deprivation and wounding increase nuclear PHA 4 101
5.2.6. Oscillating genes and genes associated with the cuticle and the unfolded protein response are upregulated in young adult aptf 1(gk794) mutants 106
5.2.7. Genetic sleep deprivation leads to a malformation of cuticular furrows 109
5.2.8. Genetic sleep deprivation leads to an increased transcription of lethargus specific oscillating genes in young adults 114
5.2.9. Genetic sleep deprivation does not significantly affect development time or body size 120
5.2.10. Expression of fluorescent reporters of oscillating genes is not phase-shifted in the aptf-1(gk794) mutant 122
6. Discussion and Outlook 128
6.1. NAS-38 acts through its astacin domain to increase sleep via innate immunity pathways 128
6.2. NAS-38 during larval lethargus and epidermal wounding in the adult signal sleep via many AMPs as part of a peripheral immune response 130
6.3. Epidermal AMPs activate a neuronal circuit to induce sleep 131
6.4. Genetically sleep deprived worms can mount a proper wounding response in many ways, except for DAF-16/FOXO regulation 132
6.5. Genetic sleep deprivation alters cuticle formation 135
6.6. The role of PHA-4/FOXA in genetically sleep-deprived animals 137
6.7. Conclusion 139
7. References 140
8. Acknowledgements 163
9. Appendix 166
9.1. Standard reagents 166
9.2. Sequence summary of PHX3754 167
9.3. MATLAB script to analyze the intensity of fluorescent reporters over time 171
9.4. Permissions to reprint figures 174
9.5. Experimental author contributions 175
9.6. Predicted interactions between the NPR-12 receptor and peptides of the nlp and cnc families 176
9.7. Overlap of the adult wounding transcriptome with other data sets 179
9.8. Curriculum Vitae – Marina Patricia Sinner 181
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Biophysical Characterization of Cell-Penetrating Peptides for Cargo Delivery or Lipid-SensingVinay K. Menon (15295864) 13 June 2023 (has links)
<p>Peptides, specifically cell-penetrating peptides (CPP), have become wonderful research tools due to their enhanced stability, solubility, and ease of synthesis. They have been used for a wide range of biomedical applications, from insecticides to biosensors and drug-delivery scaffolds. The work presented in this dissertation characterizes the biophysical properties of two different CPPs. The first is the cationic amphiphilic polyproline helix (CAPH) peptide, P14LRR. In addition to cell penetration, this CPP has demonstrated broad spectrum antibacterial properties. Fluorescence polarization (FP) and SEC-MALS were conducted to understand the dissociation constant (KD) and oligomerization effects of P14LRR with respect to its putative molecular target in Staphylococcus aureus (S. aureus). A biotinylated derivative of this peptide was also used as a drug-delivery scaffold to transport fluorescently conjugated streptavidin into mammalian cells. A second CPP, DAN13, was also developed as a biosensor for phosphoinositide lipids, specifically PI(4,5)P2. This was effected through careful calibration using stacked supported lipid bilayers (SSLB) in combination with total internal reflection fluorescence (TIRF) microscopy. This was then used to determine the absolute densities and spatial distribution of PIP2 in live KRas mutant cells.</p>
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