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35.6A: Neurodegenerativni poremećaji - biologija

35.6A: Neurodegenerativni poremećaji - biologija


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CILJEVI UČENJA

  • Razlikovati neurodegenerativne poremećaje Alzheimerove bolesti i Parkinsonove bolesti

Neurodegenerativni poremećaji su bolesti karakterizirane gubitkom funkcioniranja živčanog sustava koje su obično uzrokovane smrću neurona. Te se bolesti općenito pogoršavaju tijekom vremena jer sve više i više neurona umire. Simptomi određene neurodegenerativne bolesti povezani su s tim gdje u živčanom sustavu dolazi do smrti neurona. Spinocerebelarna ataksija, na primjer, dovodi do smrti neurona u malom mozgu. Smrt ovih neurona uzrokuje probleme u ravnoteži i hodanju. Neurodegenerativni poremećaji uključuju Huntingtonovu bolest, amiotrofičnu lateralnu sklerozu (ALS), Alzheimerovu bolest, druge poremećaje demencije i Parkinsonovu bolest. U ovom dijelu će se detaljnije raspravljati o Alzheimerovoj i Parkinsonovoj bolesti.

Alzheimerova bolest

Alzheimerova bolest je najčešći uzrok demencije kod starijih osoba. Procjenjuje se da je 2012. godine oko 5,4 milijuna Amerikanaca bolovalo od Alzheimerove bolesti. Plaćanja za njihovu skrb procjenjuju se na 200 milijardi dolara. Otprilike svaka osma osoba u dobi od 65 ili više godina ima tu bolest. Zbog starenja baby-boom generacije, predviđa se da će u Sjedinjenim Državama 2050. godine biti čak 13 milijuna pacijenata oboljelih od Alzheimerove bolesti.

Simptomi Alzheimerove bolesti uključuju ometajući gubitak pamćenja, zbunjenost oko vremena ili mjesta, poteškoće u planiranju ili izvršavanju zadataka, loše prosuđivanje i promjene osobnosti. Problemi s mirisanjem određenih mirisa također mogu ukazivati ​​na Alzheimerovu bolest i mogu poslužiti kao rani znak upozorenja. Mnogi od ovih simptoma također su česti kod ljudi koji normalno stare, pa je ozbiljnost i dugotrajnost simptoma ono što određuje da li osoba pati od Alzheimerove bolesti.

Alzheimerova bolest dobila je ime po Aloisu Alzheimeru, njemačkom psihijatru koji je 1911. objavio izvješće o ženi koja je pokazivala teške simptome demencije. Zajedno sa svojim kolegama, pregledao je ženin mozak nakon njezine smrti i izvijestio o prisutnosti abnormalnih nakupina, koje se danas nazivaju amiloidnim plakovima, zajedno sa zapetljanim moždanim vlaknima zvanim neurofibrilarni čvorići. Amiloidni plakovi, neurofibrilarni spletovi i ukupno smanjenje volumena mozga obično se vide u mozgu pacijenata s Alzheimerom. Gubitak neurona u hipokampusu posebno je ozbiljan u uznapredovalih pacijenata s Alzheimerom. Mnoge istraživačke skupine ispituju uzroke ovih obilježja bolesti.

Jedan oblik bolesti obično je uzrokovan mutacijama u jednom od tri poznata gena. Ovaj rijedak oblik rane Alzheimerove bolesti zahvaća manje od pet posto pacijenata s tom bolešću i uzrokuje demenciju koja počinje između 30. i 60. godine. Češći oblik bolesti s kasnim početkom vjerojatno također ima genetsku komponentu. Jedan određeni gen, apolipoprotein E (APOE) ima varijantu (E4) koja povećava vjerojatnost razvoja bolesti kod nositelja. Identificirani su mnogi drugi geni koji mogu biti uključeni u patologiju.

Nažalost, ne postoji lijek za Alzheimerovu bolest. Trenutni tretmani usmjereni su na upravljanje simptomima bolesti. Budući da je smanjenje aktivnosti kolinergičkih neurona (neurona koji koriste neurotransmiter acetilkolin) uobičajeno kod Alzheimerove bolesti, nekoliko lijekova koji se koriste za liječenje bolesti djeluju povećanjem neurotransmisije acetilkolina, često inhibirajući enzim koji razgrađuje acetilkolin u sinaptičkom pukotinu. Druge kliničke intervencije usmjerene su na bihevioralne terapije kao što su psihoterapija, senzorna terapija i kognitivne vježbe. Budući da se čini da Alzheimerova bolest otima normalni proces starenja, prevladavaju istraživanja o prevenciji.

Parkinsonova bolest

Parkinsonova bolest je također neurodegenerativna bolest. Prvi ga je okarakterizirao James Parkinson 1817. Svake godine 50.000-60.000 ljudi u Sjedinjenim Državama ima dijagnozu bolesti. Parkinsonova bolest uzrokuje gubitak dopaminskih neurona u supstanciji nigra, strukturi srednjeg mozga koja regulira kretanje. Gubitak ovih neurona uzrokuje mnoge simptome uključujući tremor (drhtanje prstiju ili udova), usporeno kretanje, promjene govora, probleme s ravnotežom i držanjem te ukočenost mišića. Kombinacija ovih simptoma često uzrokuje karakteristično sporo, pogrbljeno hodanje. Pacijenti s Parkinsonovom bolešću također mogu pokazivati ​​psihološke simptome, kao što su demencija ili emocionalni problemi.

Iako neki pacijenti imaju oblik bolesti za koji se zna da je uzrokovan jednom mutacijom, za većinu pacijenata točni uzroci Parkinsonove bolesti ostaju nepoznati. Bolest je vjerojatno posljedica kombinacije genetskih i okolišnih čimbenika, slično Alzheimerovoj bolesti. Post mortem analiza mozga pacijenata s Parkinsonovom bolešću pokazuje prisutnost Lewyjevih tijela, abnormalnih proteinskih nakupina, u dopaminergičkim neuronima. Prevalencija ovih Lewyjevih tijela često je u korelaciji s ozbiljnošću bolesti.

Ne postoji lijek za Parkinsonovu bolest; liječenje je usmjereno na ublažavanje simptoma. Jedan od najčešće propisivanih lijekova za Parkinsonovu bolest je L-DOPA, kemikalija koju neuroni u mozgu pretvaraju u dopamin. Ova pretvorba povećava ukupnu razinu neurotransmisije dopamina i može pomoći u kompenziranju gubitka dopaminergičkih neurona u supstanciji nigra. Drugi lijekovi djeluju tako što inhibiraju enzim koji razgrađuje dopamin.

Ključne točke

  • Neuralna smrt je glavni uzrok neurodegenerativnih poremećaja.
  • Simptomi neurodegenerativnih poremećaja obično ovise o području unutar živčanog sustava gdje dolazi do smrti neurona.
  • Alzheimerova bolest, koju karakterizira teška demencija, može se pojaviti u obliku ometajućeg gubitka pamćenja, zbunjenosti, poteškoća u planiranju ili izvršavanju zadataka, loše prosudbe i promjena osobnosti.
  • Smanjenje aktivnosti kolinergičkih neurona obično se viđa u bolesnika s Alzheimerovom bolešću.
  • Kod Parkinsonove bolesti gubitak dopaminskih neurona rezultira simptomima koji uključuju drhtanje, usporeno kretanje, promjene govora, probleme s ravnotežom i držanjem te ukočenost mišića.
  • Ni Alzheimerova ni Parkinsonova bolest nemaju lijekove, ali postoje lijekovi za kontrolu simptoma.

Ključni uvjeti

  • neurodegenerativne: koji se odnosi na ili rezultira progresivnim gubitkom živčanih stanica i neurološke funkcije
  • demencija: progresivni pad kognitivnih funkcija zbog oštećenja ili bolesti u mozgu izvan onoga što bi se moglo očekivati ​​od normalnog starenja
  • Parkinsonova bolest: degenerativni poremećaj središnjeg živčanog sustava
  • Alzheimerova bolest: poremećaj koji uključuje gubitak mentalnih funkcija kao rezultat promjena moždanog tkiva; senilna demencija

35.6A: Neurodegenerativni poremećaji - biologija

Odjeli za psihijatriju i staničnu biologiju, Medicinski centar Langone Sveučilišta New York, New York, NY, SAD

Centar za istraživanje demencije, Institut Nathan S. Kline, Orangeburg, NY, SAD

Odjeli za psihijatriju i staničnu biologiju, Medicinski centar Langone Sveučilišta New York, New York, NY, SAD

Centar za istraživanje demencije, Institut Nathan S. Kline, Orangeburg, NY, SAD

Odjel za biokemiju, Weill Cornell Medical College, New York, NY, SAD

Odjel za kardiovaskularne i bubrežne proizvode, Ured za evaluaciju lijekova I, Centar za evaluaciju i istraživanje lijekova, Uprava za hranu i lijekove Sjedinjenih Država, Silver Spring, MD, SAD

Istraživanje i razvoj sigurnosti lijekova, Pfizer Inc., San Diego, CA, SAD

Sažetak

Učinkovitost s kojom lizosomi primaju, hidroliziraju i recikliraju supstrate vitalni je aspekt stanične homeostaze koji postaje sve važniji tijekom starenja. Ovo poglavlje govori o starenju lizosomskog sustava kao ključnom čimbeniku u određivanju početka i progresije neurodegenerativnih bolesti u kasnoj životnoj dobi. Prvo ispituje disfunkciju lizosoma u neneralnim tkivima u kontekstu starenja. Zatim se u poglavlju razmatraju informacije o četiri neurodegenerativne bolesti s kasnom dobi: Alzheimerova bolest (AD), Parkinsonova bolest (PD) i srodni poremećaji, bolest Lewyjevog tijela i frontotemporalna demencija (FD). U svakom od ovih poremećaja, lizosomska disfunkcija kritički pridonosi funkcionalnom padu i gubitku neurona te razvoju prepoznatljivih proteinopatija karakteriziranih za svaki od ovih poremećaja. Poglavlje razmatra nekoliko primjera interakcija starenja lizosoma u neneralnim poremećajima i raspravlja o glavnim neurodegenerativnim poremećajima koji su najrašireniji u starijoj dobi.


7.-9. lipnja 2021. | 9:00 EDT | 13:00 UTC | 15:00 CEST*
*Program je u razvoju i podložan je promjenama

Pažnja

Dio ove konferencije uživo je završio i sve prezentacije su sada dostupne za kupnju na zahtjev. Registrirani na događaj uživo mogu pristupiti ovom sadržaju u bilo koje vrijeme do 9 mjeseci nakon događaja.

Besplatan pristup sadržaju na zahtjev znanstvenicima iz zemalja niskog i srednjeg dohotka

Keystone Symposia pozdravlja globalnu znanstvenu zajednicu i ima za cilj povezati istraživače unutar i među disciplinama kako bi se ubrzao napredak biomedicinskih znanosti i znanosti o životu. Ovaj obrazac može se koristiti za znanstvenike iz zemalja s niskim i srednjim dohotkom u svim fazama karijere kako bi odredili prihvatljivost i zatražili besplatan pristup znanstvenom sadržaju predstavljenom tijekom nedavnih događaja eSymposia. Ako ispunjavate uvjete, bit će vam poslan pristupni kod za sadržaj na zahtjev eSymposia događaja od interesa.

Neurodegenerativne bolesti, poput Alzheimerove bolesti (AD) i poremećaja povezanih s AD (ADRD) brzo postaju globalni teret. Broj dijagnosticiranih slučajeva neurodegenerativnih bolesti je zapanjujući i raste alarmantnom brzinom kako stanovništvo stari. Iako je dobro poznato da su neurodegenerativne bolesti karakterizirane nepravilnim savijanjem proteina i stvaranjem agregata, mehanizmi koji iniciraju ili promiču proteinopatiju u neuralnim krugovima specifičnim za bolest ostaju slabo razumljivi. Nedavni napredak u ljudskoj genetici i proučavanju povezanosti na razini genoma (GWAS) otkrio je nekoliko genetskih lokusa koji su kritični za patogenezu neurodegenerativnih bolesti. Nadalje, tehnološki napredak u transkriptomici, proteomici i metabolomici nudi mnoge kritične nove uvide u mehanizam bolesti, kao i mogućnosti za razvoj novih terapeutika koji mogu preokrenuti ili ublažiti neurodegeneraciju. Unatoč ovim uzbudljivim novim razvojima, postoje značajne praznine u povezivanju genetskih informacija s mehanizmom bolesti i u iskorištavanju kritične uloge interakcija glija-neurona za razvoj terapijskih intervencija.

Ova konferencija ima za cilj pružiti integriranu raspravu o najnovijim dostignućima u istraživanju i terapijskom razvoju neurodegenerativnih bolesti. Ovaj program konferencije usredotočit će se na uloge genetskih čimbenika rizika i njihov doprinos zdravlju glija i neurona u starenju mozga, biofizička svojstva pogrešnog savijanja proteina i propagaciju proteinopatije specifične za bolest, ulogu unutarstanične vezikularne trgovine u patogenezi bolesti, nove uvide u raznoliku ulogu glije, urođenog imuniteta i mikrobioma u neurodegeneraciji, te nove terapijske pristupe koji su posebno usmjereni na svako od novih bioloških područja. Očekuje se da će ova konferencija potaknuti više rasprava i promovirati nove suradnje među znanstvenicima iz akademske zajednice i industrije koje u konačnici dovode do novih terapijskih ciljeva za borbu protiv neurodegenerativnih bolesti.

Cijena:

Redovna stopa registracije: 275 USD
Stopa registracije studenata: 150 USD

Rokovi:

Podnošenje sažetka
‣ Za kratak razgovor: Prošao
‣ Za ePoster prezentaciju: Prošao
Konačna prijava ePostera/SciTalk: Prošao
Zahtjev za financijsku pomoć: Prošao

*Za slanje ePostera i/ili Scitalka potrebno je poslati sažetak


Neurodegenerativne bolesti

Prevalencija neurodegenerativnih poremećaja raste, djelomično zbog produljenja životnog vijeka. Trenutno ne postoji lijek za bilo koju od ovih bolesti, iako ne zbog nedostatka pokušaja. Naporan rad i predanost koji ulazi u razotkrivanje mehanizama bolesti vidljivi su iz ove zbirke recenzija. Svaki sažima naše znanje, ističe uzbudljive napretke i pruža dovoljno inspiracije za buduća istraživanja.

Znakovi protoka vremena jasno su vidljivi u mozgu. Tony Wyss-Coray sintetizira trenutno znanje o starenju mozga i neurodegeneraciji te istražuje mogućnost odugovlačenja, ili čak resetiranja sata.

Sve veći dokazi upućuju na to da genetska, stanična i disregulacija kola proizlazi iz, i može dovesti do staničnih i kognitivnih obilježja Alzheimerove bolesti. Li-Huei Tsai, Rebecca Canter i Jay Penney zagovaraju višestruki pristup liječenju ovog uobičajenog oblika demencije.

Paul Taylor, Robert Brown i Don Cleveland raspravljaju o novim temama i mehanizmima koji su u osnovi amiotrofične lateralne skleroze (također poznate kao Lou Gehrigova bolest ili bolest motornih neurona), progresivnoj degeneraciji motornih neurona u mozgu i leđnoj moždini.

Parkinsonovu bolest karakterizira progresivna smrt dopaminskih neurona. Asa Abeliovich i Aaron Gitler predlažu da nakupljanje staničnog oštećenja na kraju nadvlada mehanizme uklanjanja proteina ovih neurona.

John Collinge razmatra širu važnost priona sisavaca za neurodegenerativne bolesti. A Roland Riek i David Eisenberg pružaju strukturnu perspektivu neurodegeneracije kroz svojstva proteinskih agregata, obilježja različitih neurodegenerativnih poremećaja. Oni istražuju samoreplikaciju, prijenos sa stanice na stanicu i toksičnost ovih amiloida.

Nadamo se da će ova zbirka ne samo potaknuti daljnja istraživanja neurodegenerativnih bolesti, već i usmjeriti više financijskih sredstava u ovo područje — jer će veće razumijevanje otkriti nove mogućnosti za terapijske intervencije.

Priroda sa zadovoljstvom zahvaljuje na financijskoj potpori Eli Lilly and Company u izradi ovog Insighta. Kao uvijek, Priroda snosi isključivu odgovornost za sav urednički sadržaj.


Biologija ubikvitina u neurodegenerativnim poremećajima: od oštećenja do terapijskih strategija

Nenormalno nakupljanje neurotoksičnih proteina tipično je obilježje različitih neurodegenerativnih poremećaja povezanih sa dobi (NDD), uključujući Alzheimerovu bolest, Parkinsonovu bolest, Huntingtonovu bolest, amiotrofičnu lateralnu sklerozu i multiplu sklerozu. Anomalni proteini, kao što su Aβ, Tau u Alzheimerovoj bolesti i α-sinuklein u Parkinsonovoj bolesti, remete neuronsku fiziologiju i staničnu homeostazu u mozgu i tako utječu na milijune ljudskih života diljem svijeta. Ovdje, ubikvitin proteasomski sustav (UPS) igra odlučujuću ulogu u čišćenju toksičnih metabolita u stanicama, gdje se naširoko navodi da svaka aberancija preuveličava neurodegenerativne patologije. Unatoč dobrom napretku u istraživanju ubikvitinacije, njihovi molekularni markeri i mehanizmi za ubikvitinaciju i klirens proteina specifičnih za cilj ostali su nedostižni. Stoga ovaj pregled potkrepljuje ulogu UPS-a u moždanoj signalizaciji i neuronskoj fiziologiji s njihovom mehaničkom ulogom u NDD-ovom specifičnom klirensu patogenih proteina. Štoviše, raspravlja se o trenutnim i budućim obećavajućim terapijama za ciljanje neurodegeneracije posredovane UPS-om za bolje javno zdravlje.

Ključne riječi: Neurodegenerativne bolesti Signalna terapija Ubikvitin E3 ligaza Ubikvitin proteasomski sustav Ubikvitinacija.


2. dio: Parkinsonova bolest: Kako se može zaustaviti?

00:00:15.01 Bok. Ja sam Greg Petsko.
00:00:16.09 Profesor sam neurologije i neuroznanosti
00:00:18.18 na Weill Cornell Medical College
00:00:20.15 u New Yorku,
00:00:21.19 i ja sam također direktor
00:00:24.09 Institut za istraživanje Appel Alzheimerove bolesti tamo.
00:00:26.05 U ovom videu želim razgovarati s vama o tome
00:00:29.14 Parkinsonova bolest
00:00:31.03 Želim vam dati neke informacije o tome kako to počinje
00:00:33.05 i kako se to može zaustaviti.
00:00:36.17 U ranijem videu,
00:00:37.23 Rekao sam ti o općem problemu
00:00:41.13 neurodegenerativne bolesti i nadolazeća epidemija
00:00:43.04 takvih bolesti.
00:00:44.05 Parkinsonova bolest je
00:00:46.17 drugi najčešći neurološki poremećaj,
00:00:48.15 koji pogađa oko 1,5 milijuna ljudi
00:00:51.18 samo u Sjedinjenim Državama.
00:00:55.22 Ja to zovem otimač tijela,
00:00:59.22 jer vas Parkinsonova bolest ostavlja kognitivno netaknutim do samog kraja,
00:01:03.04, ali oduzima vam sposobnost tjelesnog funkcioniranja.
00:01:07.23 To je užasan poremećaj.
00:01:09.12 Potrebno je oko 20-25 godina da napreduje do smrtnog ishoda.
00:01:15.14 Kao što sam rekao, drugi najčešći
00:01:18.01 svih neurodegenerativnih bolesti.
00:01:19.17 Tipično, prosječna dob početka
00:01:22.14 star je otprilike koliko i ja,
00:01:25.01 Imam 67 godina i otprilike 1 od 7 osoba
00:01:28.15 stariji od 80 godina razviti Parkinsonovu bolest.
00:01:32.21 Ne postoje tretmani koji modificiraju tijek bolesti ili ga sprječavaju.
00:01:38.03 Postoje tretmani koji se bave simptomima,
00:01:40.21 ali dok se nose sa simptomima
00:01:43.07 bolest ide veselo dalje.
00:01:45.02 I, poput Alzheimerove bolesti, i, zapravo, poput Lou Gehrigove bolesti,
00:01:48.15 90% svih slučajeva Parkinsonove bolesti kao sporadične,
00:01:51.08 nisu naslijeđeni koliko znamo,
00:01:53.24 i oni su idiopatski
00:01:56.13 -- nismo sigurni što ih uzrokuje.
00:01:58.04 10%, međutim, je genetski,
00:02:00.15 trčati u obiteljima s bilo autosomno dominantnim
00:02:03.02 ili autosomno recesivno nasljeđivanje,
00:02:07.00 i ti slučajevi, kao što ćete vidjeti,
00:02:10.11 su nas naučili dosta o tome što se događa s ovom bolešću.
00:02:12.21 Bolest je prvi identificirao James Parkinson
00:02:17.11 još u 19. stoljeću
00:02:19.17 i to je fascinantna priča,
00:02:21.23 o čemu je pisao u svom malom eseju,
00:02:23.23 koju je nazvao Tresuća paraliza,
00:02:26.00, ali sada Parkinsonovu bolest zovemo po njemu.
00:02:28.01 On je bio prva osoba koja je ovo opisala kao redoviti poremećaj,
00:02:31.04 iako postoji opis onoga što mora biti Parkinsonova bolest
00:02:33.13 koji sežu tisućama godina unatrag u kineskim svicima,
00:02:37.01 tako da je to bila nevolja koja je mučila ljudsku rasu
00:02:42.05 jako dugo.
00:02:45.02 Ali Parkinson je to zapravo iznio kao jasan klinički fenomen,
00:02:48.21 i to je učinio na temelju samo 5 pacijenata,
00:02:51.18 samo s dvoje s kojima je zapravo osobno razgovarao.
00:02:54.24 Ostala 3 promatrao je dok je šetao ulicama Londona.
00:02:59.07 Ako želite znati kako postaviti neurološku dijagnozu,
00:03:03.02 pročitajte ovu monografiju -- briljantna je.
00:03:07.16 Michael J Fox jedna je od najpoznatijih žrtava
00:03:12.14 ove bolesti.
00:03:14.09 Ima, koliko znamo, sporadični oblik bolesti
00:03:17.04 i nije imao sreće da ga dobije vrlo mlad, u kasnim 30-ima.
00:03:19.06 To je, u njegovom slučaju,
00:03:22.24, bolest koju je koristio kao odskočnu dasku
00:03:25.19 za stvaranje privatne zaklade, Michael J Fox Foundation,
00:03:29.03 koji je jedan od vodećih pobornika Parkinsonove bolesti
00:03:32.21 istraživanje u svijetu.
00:03:35.02 Sama bolest,
00:03:38.12 pa, ima otprilike istu učestalost kao rak štitnjače,
00:03:40.18 i, kao što sam rekao, ima oko 1,4 milijuna ljudi
00:03:43.04 živjeti s bolešću u bilo kojem trenutku,
00:03:46.22 i obično je potrebno 20-25 godina
00:03:50.11 napredovati u smrt.
00:03:52.24 O, rekao bih,
00:04:01.07 1/4 do 1/3 tih pacijenata također postaje dementno,
00:04:04.06 prema završnoj fazi bolesti,
00:04:06.18 i to je samo užasan poremećaj.
00:04:09.11 Nemamo ništa što bi modificiralo tijek bolesti.
00:04:11.22 Identificirali smo brojne gene
00:04:13.22 koji su odgovorni za neke od obiteljskih slučajeva
00:04:16.24 i, kao što sam rekao, naučili su nas puno o poremećaju,
00:04:19.16, ali još uvijek nemamo načina da to zaustavimo.
00:04:23.04 I još uvijek nismo sigurni koji su uzroci
00:04:25.14 sporadične slučajeve bolesti,
00:04:27.06 za koje ne postoje očiti genetski uzroci.
00:04:30.21 Međutim, postoje čimbenici rizika.
00:04:32.08 Znamo da postoje stvari koje to čine vjerojatnijim
00:04:35.04 dobit ćete Parkinsonovu bolest.
00:04:37.00 Jedna od njih bi bila ozljeda glave od nesreća
00:04:40.10 ili, u ovom slučaju, iz boksa.
00:04:42.15 Mohammed Ali je poznati bolesnik od Parkinsonove bolesti.
00:04:44.18 Zanimljivo je da
00:04:46.18 infekcija mozga virusima,
00:04:49.01 koji je također, u mnogim slučajevima, preteča Parkinsonove bolesti.
00:04:52.02 Epidemija ptičje gripe 1918.-1920.
00:04:56.01 pratila je, zapravo, epidemija Parkinsonove bolesti,
00:04:58.12 za mnoge ljude koji su preživjeli gripu.
00:05:01.06 Znamo da određeni mitohondrijski otrovi,
00:05:04.09 stvari koje oštećuju mitohondrije,
00:05:06.08 neki pesticidi na primjer,
00:05:08.06 zapravo će dati Parkinsonovu bolest kod životinjskih modela
00:05:12.12 i zapravo će ljudima dati Parkinsonovu bolest
00:05:15.04, koji ih zaobilaze i unose ih previše.
00:05:17.15 Visok kolesterol je faktor rizika za Parkinsonovu bolest.
00:05:20.22 nije jasno zašto.
00:05:22.14 I ljudi s lizosomskim bolestima skladištenja
00:05:25.03 ili ljudi koji su nositelji genetskih bolesti lizosomskog skladištenja,
00:05:28.23 imaju mnogo veću učestalost Parkinsonove bolesti.
00:05:31.20 Opet, razlozi zašto nisu baš jasni.
00:05:34.17 Ali možda biste željeli zapamtiti ovaj popis,
00:05:37.01 jer ćemo se na to vratiti kasnije.
00:05:39.18 Razlog zbog kojeg imate simptome Parkinsonove bolesti,
00:05:43.11 podrhtavanje, sporost kretanja,
00:05:46.13 posturalnu nestabilnost, sve užasne stvari
00:05:50.03 što može poći po zlu s vama fizički,
00:05:51.16 je zato što brzo gubite određeni skup neurona
00:05:55.24 tijekom bolesti.
00:05:57.14 Ti neuroni jesu
00:06:00.09 dopaminergički neuroni crne supstancije,
00:06:03.12 dio srednjeg mozga koji proizvodi dopamin
00:06:05.10 i koji šalje svoje aksone u nigrostriatalni put,
00:06:11.09 koji kontrolira glatkoću pokreta.
00:06:13.23 Možete vidjeti uspoređujući ljevicu, normalnu osobu,
00:06:17.13 s pacijentom s Parkinsonovom bolešću desno,
00:06:21.16 da ste izgubili puno te crne tvari
00:06:23.24 -- to su neuroni koji proizvode dopamin.
00:06:27.07 I obično, zapravo, oko 70% tih neurona je nestalo
00:06:31.21 kada imate simptome bolesti.
00:06:34.22 Ako pogledate te neurone
00:06:37.16 tijekom bolesti,
00:06:40.01 u njima ćete pronaći nešto što ne bi trebalo biti tamo.
00:06:43.00 Oni su gusti agregati pogrešno savijenog proteina,
00:06:46.02 zovu se Lewyjeva tijela po francuskom liječniku
00:06:49.07 tko ih je prvi identificirao,
00:06:51.13 i to možete vidjeti na ovom slajdu
00:06:54.12 boje se pretežno na ubikvitin
00:06:56.22 i za protein koji se zove sinuklein,
00:06:58.16 koji je protein specifičan za središnji živčani sustav
00:07:01.02 o kojem se funkcionalno ne zna previše.
00:07:04.09 Primijetit ćete i da su prilično upečatljive strukture
00:07:06.18 -- sinuklein je izvana
00:07:09.01 i ubikvitin je iznutra.
00:07:10.21 Nitko ne zna zašto je to istina.
00:07:13.07 Ali ako biokemijski analizirate Lewyjeva tijela,
00:07:16.11 i mi i drugi smo to učinili,
00:07:18.23 otkrijete da sadrže pretežno α-sinuklein,
00:07:21.07 tu je i fragment α-sinukleina,
00:07:24.01 a tu je i ubikvitin, kao što sam rekao,
00:07:26.22 a tu je i puno drugih stvari u raznim količinama,
00:07:29.14 i više, ovisno o tome koliko ste voljni izgledati
00:07:32.11 duboko u popis sporednih komponenti.
00:07:37.24 Evo α-sinukleina. To je protein dugačak 140 aminokiselina.
00:07:41.02 Kao što sam rekao, ne znamo toliko o tome funkcionalno
00:07:43.23 kako bismo trebali,
00:07:45.19, ali ono što znamo je to
00:07:49.00 neke od mutacija koje uzrokuju Parkinsonovu bolest
00:07:52.07 se javljaju u ovom proteinu,
00:07:54.14 i te su mutacije ovdje prikazane crvenom bojom.
00:07:58.12 Ti ostaci, mutirani kao što vidite ovdje,
00:08:02.06 jamči da ćete dobiti Parkinsonovu bolest
00:08:04.19 i, općenito govoreći, obično ga dobijete malo ranije.
00:08:07.12 Uz to, postoje rijetke obitelji
00:08:10.07 koji imaju slijed α-sinukleina divljeg tipa,
00:08:13.15 ali to ima dupliciranja ili utrostručenja
00:08:16.04 gena α-sinukleina,
00:08:18.14 tako da samo imaju veće opterećenje divljeg tipa α-sinukleina,
00:08:21.19 i dobiju Parkinsonovu bolest,
00:08:24.02 i mladi dobiju Parkinsonovu bolest.
00:08:26.04 Dakle, ovi genetski čimbenici
00:08:29.03 snažno implicira sinuklein,
00:08:32.00 koji se uostalom nalazi u agregatima,
00:08:35.15 kao kritična komponenta za Parkinsonovu bolest.
00:08:42.02 Odradili smo puno posla prije nekog vremena,
00:08:44.17 sažeto na ovom slajdu, koji je pokazao da,
00:08:47.05 pod pravim okolnostima,
00:08:49.04 možete pripremiti α-sinuklein kao prilično stabilan,
00:08:51.20 uglavnom alfa-helikalni tetramerni protein,
00:08:54.09 čiji je NMR bio onaj djelomično presavijenog proteina,
00:08:57.02 osim ako ga niste denaturirali,
00:08:59.13 u kojem slučaju je, naravno, postao poremećeni protein,
00:09:02.03 i da ovaj protein
00:09:06.19 u osnovi je bio nevjerojatno stabilan tijekom vremena.
00:09:09.14 osim ako ga niste denaturirali, u tom slučaju se brzo nakuplja
00:09:12.23 -- to je crvena krivulja, tamo --
00:09:15.06 i formirali stvari koje izgledaju kao mala Lewyeva tijela --
00:09:17.06 filamentozni, amiloidni agregati α-sinukleina.
00:09:21.16 I ovi eksperimenti, koji su objavljeni,
00:09:24.13 pokrenuo je pitanje koje nas je jako mučilo.
00:09:27.13 Ako je, u osnovi, α-sinuklein
00:09:30.02 nije toliko sklon agregaciji,
00:09:32.11 osim ako nemate mutante.
00:09:34.06 Mislim, ako stavite mutante koji uzrokuju Parkinsonovu bolest
00:09:36.23 u α-sinuklein,
00:09:38.13 gubite puno spiralne strukture i dobivate brzo agregiranje,
00:09:41.14 kao što možete vidjeti ovdje.
00:09:42.19 Pa, to ima smisla,
00:09:46.03, ali zapamtite, većina ljudi s Parkinsonovom bolešću
00:09:48.02 nemaju nikakve mutacije u α-sinukleinu
00:09:50.01 -- sporadično je i idiopatsko,
00:09:52.01 ipak imaju α-sinuklein Lewyjeva tijela,
00:09:53.22 agregati α-sinukleina.
00:09:55.18 Dakle, ako α-sinuklein nije intrinzično sklon toj agregaciji,
00:09:59.12 kako onda, dovraga, itko ikada dobije Parkinsonovu bolest?
00:10:03.12 To je bilo pitanje na koje smo htjeli odgovoriti.
00:10:09.01 I činilo nam se da je to način rješavanja tog problema
00:10:13.03 možda bi bilo vratiti se i ponovno pogledati ta Lewyjeva tijela,
00:10:17.14 jer, zapamtite,
00:10:20.16 postoji fragment α-sinukleina
00:10:23.13 koji je pronađen u Lewyjevim tijelima.
00:10:25.03, A to je zapravo vrlo specifičan fragment, ovdje.
00:10:28.00 I pitali smo se, što je s tim fragmentom?
00:10:33.02 Dakle, izvukli smo to, napravili smo masovne preglede,
00:10:35.11 i otkrili smo da je fragment proizveden
00:10:38.01 cijepanjem nakon asparaginske kiseline 121
00:10:41.05 -- Ovdje je ona crvena strelica, ovdje.
00:10:44.05 I ono što možete vidjeti je
00:10:47.14 zadnjih 19 ostataka α-sinukleina se odcijepi.
00:10:51.01 To je taj fragment.
00:10:52.22 Dakle, napravili smo taj fragment,
00:10:55.04 upravo je dizajnirao gen za to, napravio protein,
00:10:58.04 i pogledao ga.
Ispostavilo se da se protein ponaša vrlo drugačije
00:11:02.19 iz α-sinukleina pune duljine.
00:11:04.17 Zbira se kao ludo
00:11:08.03 i to je privuklo našu pozornost.
00:11:11.00 Ako je fragment u Lewyjevim tijelima
00:11:14.01 i ako se fragment puno bolje agregira
00:11:16.21 nego α-sinuklein pune duljine,
00:11:18.22 onda možda formiranje fragmenata
00:11:22.03 je vrlo rani događaj u bolesti.
00:11:24.03 Možda je, zapravo, rani događaj u sporadičnoj bolesti
00:11:27.20 -- to je ono što pokreće agregaciju proteina pune duljine?
00:11:31.24 Ako je to istina, onda je pitanje očito,
00:11:35.15 što reže α-sinuklein na ostatku 121?
00:11:38.19 Što je proteaza,
00:11:41.03 enzim za rezanje proteina
00:11:44.00 to radi ovaj posao, jer su proteaze velike mete lijekova
00:11:47.01 -- znamo kako inhibirati proteaze.
00:11:48.20 Problem je što postoje stotine proteaza u ljudskom genomu,
00:11:52.06 i mnogi od njih su esencijalni geni,
00:11:55.21, tako da je vrlo teško shvatiti što bi mogla biti prava proteaza.
00:12:00.02 I tako, da to učinite,
00:12:02.12 okrenuli smo se uzornom organizmu,
00:12:04.06, a model organizma kojem smo se obratili je kvasac.
Sada znam što misliš.
00:12:10.16 Razmišljaš, čekaj malo, kvasac nema mozak.
00:12:13.14 To je istina.
00:12:16.04 Ali ako ste pratili sezonu predsjedničkih primarnih,
00:12:18.18 znate da nema svaka osoba mozak.
00:12:22.061 Dakle, jasno je da mozak nije bitan.
00:12:25.07 I, zapravo, iako kvasac nema mozak,
00:12:27.23 to je sjajan model organizma
00:12:30.04 ako se pitate što se događa u temeljnim staničnim procesima.
00:12:36.02 A laboratorij Tiaga Outiera i Susan Lindquist pokazao je prije 15 godina
00:12:40.10 da je α-sinuklein otrovan za kvasac
00:12:42.16 kada to pretjerano izrazite.
00:12:44.05 Ubija ćeliju.
00:12:46.17 I, zapravo, čineći to,
00:12:48.22 proizvodi, kao što možete vidjeti na lijevoj strani,
00:12:50.19 proizvodi ovo fantastično malo
00:12:55.14 Agregati nalik Lewyjevom tijelu.
00:12:57.060,0:12:57.06 A to sugerira da se možda nešto događa u kvascu
00:13:02.10, to je donekle slično onome što se događa u neuronu.
00:13:06.030,0:13:06.03 Pa, Tiago i Sue su radili puno toga
00:13:08.20 fascinantni genetski eksperimenti s ovim sustavom,
00:13:10.19, ali nisu izgledali biokemijski
00:13:13.01 što se događalo u tim agregatima,
00:13:14.23 pa smo mislili da je ovo dobra prilika za to.
00:13:17.22 Izvukli smo te agregate iz kvasca i analizirali ih
00:13:20.06 i, pogodite što, sadrže potpuno isti fragment
00:13:23.02 koje možete pronaći u Lewyjevim tijelima ljudi.
00:13:26.18 potpuno isti fragment.
00:13:30.02 Što znači da kvasac sadrži proteolitičku aktivnost
00:13:33.06 sposoban rezati α-sinuklein na istom mjestu
00:13:36.16 da je usječen u neurone.
00:13:39.02 Pa, fascinantna stvar u vezi s kvascem, naravno,
00:13:43.02 nema 500 proteaza u kvascu -- ima ih oko 50.
00:13:47.020,02 I možete vrlo jednostavno napraviti genetiku u kvascu.
00:13:50.08 Dakle, ono što smo napravili je dizajn ekrana
00:13:52.18 u kojem smo uzeli kvasac s prekomjernom ekspresijom α-sinukleina
00:13:56.01 koji bi inače umro
00:13:58.09 i nokautirali smo, jednog po jednog,
00:14:00.04 geni proteaze u kvascu.
00:14:02.05 I postavili smo pitanje,
00:14:04.03 možemo li pronaći proteazu koju, ako je se riješite,
00:14:07.07 α-sinuklein se više ne agregira u kvascu
00:14:10.10 i kvasac može preživjeti?
00:14:12.17 Nema fragmenta, nema agregacije, opstanak stanice.
00:14:16.19 Jednostavan genetski ekran.
00:14:18.13 Pregledali bismo 5500 delecija genoma kvasca,
00:14:24.23 ako biste pregledali svaki gen kvasca,
00:14:27.19 ali zapamtite, probiramo samo proteaze,
00:14:30.17 pa smo pregledali 50,
00:14:32.08, a to je lako učiniti.
00:14:35.02 I ispostavilo se da postoje dva koja, kada se izbrišu,
00:14:38.12 zapravo spašava stanice od toksičnosti α-sinukleina.
00:14:43.20 Jedan od njih je YCA1,
00:14:45.18 koji je jedini homolog kvasca iz obitelji zvane kaspaze,
00:14:49.19 a drugi je RIM13,
00:14:52.01 koji je jedini homolog kvasca
00:14:55.00 iz obitelji proteaza zvanih kalpaini.
00:14:57.08 A u kvascu su te proteaze povezane
00:14:59.24 -- jedno aktivira drugo --
00:15:01.20, tako da vjerojatno gledamo na jedan proteolitički događaj.
00:15:03.24 A ovo su obje cisteinske proteaze,
00:15:06.00, ovdje je posebna obitelj proteaza.
00:15:12.07 Pa, sada smo uvelike pojednostavili problem,
00:15:14.06 jer u neuronima postoji 29 kaspaza plus kalpaini,
00:15:24.08 i to je broj kojim se može upravljati.
00:15:26.06 Dakle, što smo onda namjeravali učiniti
00:15:30.11 trebalo ih je srušiti jednog po jednog
00:15:32.16 i da vidimo možemo li vidjeti isto što su vidjeli u kvascu,
00:15:35.01 jer u kvascu, kada smo srušili proteazu,
00:15:37.18 više nije bilo fragmenta i nije bilo agregacije,
00:15:41.06 i to je lako tražiti u neuronima.
00:15:43.08 Dakle, koristili smo RNA interferenciju
00:15:47.09 da sruši svaki od gena kaspaze i kalpaina u kvascu.
00:15:52.15 oprostite, u neuronima.
00:15:57.04 i da saznamo možemo li vidjeti fenotip,
00:16:00.24 u odnosu na ono što smo vidjeli u kvascu.
00:16:05.02 Trebali smo model u neuronima Parkinsonove bolesti.
00:16:07.17 Mark Cookson je dao jedan.
00:16:09.20 To je model u kojem,
00:16:12.08 normalno, kao što možete vidjeti s lijeve strane,
00:16:14.00 oksidativni stres nije osobito toksičan za neurone u kulturi
00:16:18.21 osim ako pretjerano ekspresirate α-sinuklein,
00:16:21.07 to je lik s desne strane,
00:16:23.07 u kojem slučaju, pri određenoj graničnoj koncentraciji
00:16:27.01 kemikalije oksidativnog stresa,
00:16:28.22 stanice brzo umiru jer imaju α-sinuklein.
00:16:31.22 I ovaj model je korišten za
00:16:34.08 dosta godina,
00:16:37.12, ali nitko nije razumio zašto morate imati i oksidativni stres i α-sinuklein.
00:16:40.03 α-sinuklein sam po sebi nije bio otrovan,
00:16:42.03 trebala vam je ogromna količina oksidativnog stresa bez α-sinukleina.
00:16:45.14 koji je razlog sinergije?
00:16:47.14 Dakle, pogledali smo ovaj model i pronašli smo
00:16:50.06 razlog je fragment.
00:16:52.11 Ispada da se fragment pojavljuje
00:16:54.18 -- možete vidjeti tamo gdje je strijela --
00:16:56.21 točno u koncentraciji induktora oksidativnog stresa,
00:16:59.18 menadione.
00:17:02.07 točno u koncentraciji u kojoj [menadion] postaje otrovan u prisutnosti α-sinukleina,
00:17:06.20 gdje stanice počinju umirati.
00:17:09.18 Dakle, stvaranje fragmenata izravno je povezano s toksičnošću u ovom modelu
00:17:13.06 -- to je upravo ono što nam treba
00:17:15.18 za naše eksperimente nokautom.
00:17:17.21 So, we took this model and, one by one,
00:17:19.22 we knocked out the caspases and calpains.
00:17:22.11 And only one of them made a difference
00:17:26.01 and that one was caspase-1.
00:17:28.23 You can see, for example,
00:17:31.09 on the left that when you knock down caspase-9
00:17:35.19 you still have the fragment,
00:17:37.18 there where the red arrow is,
00:17:39.10 whereas when you knock down caspase-1 the fragment disappears.
00:17:42.20 So, it's caspase-1.
00:17:45.13 And caspase-1 got our attention big time,
00:17:49.09 because even though it has the same name
00:17:52.03 as a cell-death protease,
00:17:56.01 caspase-1 is not a cell death protease.
00:17:58.21 It is a cysteine protease,
00:18:00.24 but what it is it's the major inflammatory protease
00:18:04.24 of the human genome.
00:18:08.01 Caspase-1 is linked to inflammation.
00:18:13.01 And we did a quick set of experiments
00:18:15.13 summarized on this slide,
00:18:20.05 in which we proved that, in vitro,
00:18:22.16 caspase-1 could cleave α-synuclein to make the fragment,
00:18:25.24 that's the figure on the upper left,
00:18:27.18 and that the fragment was cleaved at the right place,
00:18:29.22 that's the mass spec on the lower left,
00:18:32.04 and that if you added a pinch of caspase-1
00:18:34.03 to a stable preparation of α-synuclein, here,
00:18:38.04 α-synuclein rapidly aggregated.
00:18:43.01 So, this looks like it has the characteristics of the protease
00:18:45.21 that we're looking for:
00:18:47.23 it cleaves in the right place,
00:18:50.18 the reduction of the protein to a smaller fragment
00:18:53.05 produces an aggregation-prone fragment.
00:18:55.11 everything we wanted seems to be here.
00:18:58.11 And caspase-1, because of its role in inflammation,
00:19:01.09 has been studied for 30 years.
00:19:03.10 There are good crystal structures.
00:19:05.08 Here's one we did, but there are many that were done before.
00:19:08.17 And, even better, there are chemical inhibitors for caspase-1.
00:19:16.08 People, years ago, were interested in inhibiting this enzyme
00:19:20.12 for treatment of psoriasis, arthritis,
00:19:22.22 and other inflammatory diseases.
00:19:24.18 Now, in fact, none of those drugs did a lot,
00:19:27.12 because inflammatory diseases involve
00:19:30.02 more than just caspase-1,
00:19:32.01 but they made a lot of inhibitors,
00:19:34.04 and some of these inhibitors were even tested in people
00:19:36.21 and were found to be safe.
00:19:38.21 Unfortunately,
00:19:42.00 almost none of them get into the brain
00:19:44.03 they don't have good blood-brain barrier penetrance.
00:19:46.21 The best one is the one at the top, here,
00:19:49.00 which is VX-765 from a company called
00:19:52.09 Vertex Corporation.
00:19:54.20 It's a pro-drug that's converted into to the active drug inside a cell.
00:19:58.03 That has some brain penetrance, but it's not great.
00:20:01.06 We did, however, start to use it
00:20:05.01 to see if it would work in neurons in our neuronal model of the disease.
00:20:08.13 And, in a dose-dependent manner,
00:20:11.03 it restored survival of those neurons
00:20:13.18 in the presence of α-synuclein plus menadione.
00:20:16.14 Just what you'd expect if you were inhibiting caspase-1
00:20:20.10 and preventing the fragment formation.
00:20:22.06 The neuron should survive,
00:20:24.13 just like the yeast survive, and they do.
00:20:27.21 And so this is a chemical equivalent of knocking out the gene,
00:20:30.24 and it works.
00:20:32.13 If only. if only.
00:20:35.04 we had a blood-brain penetrant version of this inhibitor,
00:20:37.00 we could immediately try it in animal models of Parkinson's Disease,
00:20:40.10 but at the moment we're still trying to find
00:20:43.01 such a compound.
00:20:45.01 However, what I've shown you, I hope,
00:20:47.21 is an explanation for at least some of the sporadic cases of Parkinson's Disease.
00:20:52.14 If inflammation triggers caspase-1
00:20:56.23 and caspase-1 cleaves α-synuclein
00:20:59.22 to an aggregation-prone fragment,
00:21:02.15 and that aggregation-prone fragment
00:21:05.00 then produces various amyloid-like substances
00:21:08.12 that are then toxic to the cell,
00:21:10.08 you've got a reasonable model for how Parkinson's Disease might start.
00:21:13.09 It does raise the question, though,
00:21:16.04 do we have any evidence
00:21:18.23 that this really happens in Parkinson's Disease?
00:21:20.18 The first thing I'd like to ask is,
00:21:22.13 what activates caspase-1?
00:21:24.02 You don't want to have an active protease running around in the cell.
00:21:27.12 Well, the answer is caspase-1 is activated
00:21:29.07 by a complex called the inflammasome.
00:21:30.24 It's normally part of the inflammasome
00:21:32.24 and when the inflammasome,
00:21:35.00 which is a sensor of inflammatory events, is activated,
00:21:38.12 caspase-1 becomes activated.
00:21:41.05 Okay, so what activates the inflammasome?
00:21:44.20 Cholesterol deposits, viral infection,
00:21:48.05 head trauma, mitochondria poisons will do it,
00:21:52.02 and lysosomal damage will activate the inflammasome.
00:21:57.04 Does this look familiar to you?
00:22:00.18 Yeah. this was the list factors I showed you earlier
00:22:04.07 of the risk factors for sporadic Parkinson's Disease.
00:22:06.07 they happen to be the things that activate the inflammasome.
00:22:09.02 It might be just a coincidence,
00:22:10.23 but it fits beautifully with the model that we're talking about.
00:22:16.09 And here's something else that fits.
00:22:19.08 If you actually look in the brains of Parkinson's Disease patients,
00:22:22.15 caspase-1 is highly active
00:22:29.01 in precisely the region, the substantia nigra,
00:22:33.00 that is most vulnerable in the disease.
00:22:34.14 You can see that, there, in the red bar in the middle.
00:22:38.08 So, I think we have a plausible hypothesis
00:22:41.10 for how Parkinson's Disease starts,
00:22:43.11 that inflammatory events activate the inflammasome,
00:22:46.12 that the inflammasome then produces active caspase-1,
00:22:49.23 which cleaves α-synuclein, and so forth.
00:22:54.06 If this is how Parkinson's Disease starts in many cases,
00:22:58.06 then it's also how Parkinson's Disease might be stopped,
00:23:01.12 and all we have to do in order to stop Parkinson's Disease
00:23:05.14 might be to find
00:23:08.03 a blood-brain barrier penetrant form of caspase-1 inhibitor,
00:23:12.19 and that's something we're actively pursuing in my lab right now.
00:23:17.08 So, we haven't quite gone yet from molecule to man,
00:23:20.08 but I'm hoping we will,
00:23:23.11 and we'll get a chance to test this hypothesis
00:23:26.03 the way this has to be tested,
00:23:28.08 in animal and then eventually human disease.
00:23:31.04 If we can show that,
00:23:33.12 then we might eventually be able to provide someone with a disease-modifying treatment,
00:23:40.07 not just a symptomatic treatment for Parkinson's Disease.
00:23:45.05 Now, they saw no man is an island.
00:23:48.00 It's particularly true in scientific research.
00:23:50.07 This is the team that's been working on this problem.
00:23:53.14 My colleague, Dagmar Ringe at Brandeis,
00:23:56.05 postdoc Quyen Hoang,
00:23:58.10 who did many of the experiments I've shown you,
00:24:00.10 together with postdoc Shulin Ju.
00:24:02.10 And our collaborators at Brandeis,
00:24:04.24 at Bordeaux,
00:24:06.21 and at Rush Medical School and NIH,
00:24:09.03 who've helped us along the way with many of the things
00:24:12.02 that we've had to do that we weren't familiar with.
00:24:15.00 Thank you.


Metode

Sample

Patients with a clinical diagnosis of HD, dementia and AT were included in the study (Table1). The subjects in the HD group had been symptomatic for 5 years (SD, 3.3), with a mutated allele of the CAG repeats ranging from 40 to 85. The HD sample was part of a larger study of genetic and clinical correlates in HD, and details about evaluation have been reported earlier. 15

TABLE 1. Clinical Characteristics of Study Groups Showing Age- and Gender-Matched Cases and Control Subjects a

a Age and gender distribution did not differ between the cases and controls (p>0.05). AAA: age at assessment and blood sampling AAO: age at onset of disease NA: data not available.

TABLE 1. Clinical Characteristics of Study Groups Showing Age- and Gender-Matched Cases and Control Subjects a

The dementia subjects (N=70) were diagnosed by ICD-10 criteria and were evaluated using the Hindi Mental Status Examination scale. 16 The dementia group subjects had been symptomatic for 2.8 years (SD, 1.9), with Hindi Mental Status Examination scale scores of 11.2 (SD, 7.7). Dementia of Alzhiemer’s type formed the major group (N=57), followed by vascular dementia (N=8), fronto-temporal dementia (N=2), and Lewy body dementia (N=3).

The AT cases (N=9) were clinically diagnosed and confirmed by elevated alpha-feto protein levels. The control subjects (N=105) were corresponding age-matched subjects recruited from the general population and had no lifetime history of psychiatric illness and no known family history of neuro-psychiatric illness. Hindi Mental Status Examination scale score in control subjects for the dementia group (N=55) was 30.8 (SD, 0.7).

The study was approved by the Institutional Ethics Committee, National Institute of Mental Health and Neurosciences, Bangalore. After informed written consent, 10 mL of venous blood was collected, and DNA was isolated using the salting out method. 17 The real-time polymerase chain reaction (PCR) was setup using the Applied Biosystems 7500 system where the telomere and a single copy gene in a known quantity of DNA were amplified simultaneously and the results were recorded as number of cycles of real-time PCR required to reach threshold fluorescence (Ct or cycle threshold).

The Ct value is inversely related to the initial copy number of telomere or single copy gene. The T/S ratio (or ΔCt=Ct of telomere amplification − Ct of single copy gene amplification), which reflects number of copies of telomere per diploid genome in an assay, is an indirect measure of telomere length. The relative T/S ratio, which is calculated as the difference between ΔCt of unknown sample and normalized for ΔCt of reference DNA, enables comparison of T/S ratios across assays. 14 The following formula was used to calculate relative T/S ratios: The reference sample was an arbitrarily chosen sample that was included in all experimental assays to permit interassay comparison. Each sample was assayed in duplicate, and Ct values that showed SD > 1 between the technical replicates were not considered for analysis. Experiments were repeated after recoding the DNA samples to eliminate sample bias.

Reproducibility of the Measured Relative T/S Ratios

Replicate assays of same sample and reference were setup at different times to calculate the interassay variation. The coefficient of variation (average standard deviation) as calculated by measuring relative T/S ratios of a sample repeated over four different assays was 6.7%. Thus, samples differing in average telomere length by as little as 13% (1.96×SD) should be distinguishable by this method at the 95% confidence interval. 14

Statistička analiza

Statistical tests were done using R software 18 and QTI plot. 19 The chi-square test was used for comparing categorical variables. Mann-Whitney U test (U, two-tailed p) and Kruskal-Wallis test (χ 2 , p) were used for comparison between groups of continuous variables as the relative T/S ratios and log-transformed relative T/S ratios calculated were not normally distributed and nonparametric tests are most useful for small samples. 20 , 21 Spearman's rank correlation (r, two-tailed p) and partial correlation (r, two-tailed p) coefficients were used for correlation analysis.


Diagnosis [ edit | uredi izvor ]

Neurodegenerative diseases are often presented as a distinct entity, however there is often overlap as you may have noted in the above descriptions, eg for AD and Lewy body pathologies. None of the neurodegenerative disorders have perfect diagnostic accuracy, and neuropathology will continue to be the gold standard for the foreseeable future.

  • Studying disease heterogeneity at autopsy is key to understanding discrepancies between clinical and pathological diagnoses. This is a critical concept because there are many efforts to develop biomarkers to diagnose these diseases and to monitor disease progression in clinical trials [5]

Scientists discover cellular stress enzyme that might play key role in neurodegenerative diseases such as ALS

An enzyme called MARK2 has been identified as a key stress-response switch in cells in a study by researchers at Johns Hopkins Bloomberg School of Public Health. Overactivation of this type of stress response is a possible cause of injury to brain cells in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Amyotrophic Lateral Sclerosis. The discovery will make MARK2 a focus of investigation for its possible role in these diseases, and may ultimately be a target for neurodegenerative disease treatments.

In addition to its potential relevance to neurodegenerative diseases, the finding is an advance in understanding basic cell biology.

The paper describing the discovery appears online March 11 in PLoS biologija.

The study focused on the cellular response to "proteotoxic" stress—a buildup of damaged or aggregated proteins within the main part of the cell, which is a central feature of neurodegenerative diseases. It has been known that cells respond to this type of stress by reducing their production of new proteins, and that a signaling enzyme likely mediates this response. The researchers, after ruling out other signaling enzymes, were able to show that the signaling enzyme MARK2 has this role.

"Further studies of this previously unrecognized signaling pathway should expand our understanding of protein regulation in cells and the role of this process in the development of human diseases," says Jiou Wang, Ph.D., a professor in the Department of Biochemistry and Molecular Biology at the Bloomberg School.

Together, Alzheimer's, ALS, and other neurodegenerative disorders afflict well over 50 million people worldwide. To date there is no disease-slowing treatment, let alone a cure, for any of them—primarily because their causes are not well understood.

One possible set of causes of neurodegenerative disorders relates to the proteotoxic stress and the response in brain cells. When this response is activated, reducing protein synthesis, it ideally minimizes the protein burden of the cell under proteotoxic stress, thereby allowing it to recover from the stress. But the long-term reduction of protein synthesis could end up starving the cell of needed proteins, injuring it, and potentially triggering cell death. In other cases, the failure of the proteotoxic stress response, rather than its overactivation, may be the problem, so that protein overload leads to cell injury or death.

To fully understand either scenario, scientists need to understand the signaling pathway that senses proteotoxic stress and switches on the proteotoxic stress response. Wang and colleagues in their new study set out to discover it.

Like others in this field, the research team already knew that the molecule at the end of this pathway that switches off protein production is a member of a broad class of signaling enzymes called kinases. They also knew in advance that there are several specific kinases that switch off protein production in the same way, but in response to other types of cellular stress, such as viral infection. The challenge in this study was to find the specific kinase that throws this switch in response to proteotoxic stress in the main part of the cell.

The researchers first identified the kinase MARK2 as one of several candidates for their inquiry by sifting through a large database, produced with prior research, of various kinases and the proteins they potentially act upon. Following up their leads with various cell-free and cell culture experiments, they were able to show that MARK2, and no other candidate kinase, can switch off the protein-making machinery in cells in response to proteotoxic stress, even when the other four known protein-shutdown kinases are absent.

Looking upstream in the signaling pathway, the team found that MARK2 is activated by another signaling kinase, PKCδ, which becomes available for its MARK2-activating role under conditions of proteotoxic stress, thus effectively acting as a proteotoxic stress sensor.

As a preliminary check on the clinical relevance of these findings, the researchers examined a mouse model of familial ALS and samples of spinal cord tissue from human ALS patients. They found evidence that this PKCδ-MARK2 pathway is highly active in these cases compared to non-ALS mice and humans.

"These findings are consistent with the idea that in ALS, for example, this PKCδ-MARK2 pathway is highly active and reducing protein production, which over the long term contributes to the disease process," Wang says.

Having clarified the basics of how this pathway works, Wang and colleagues are now planning to study it in different neurodegenerative disease models to determine whether the pathway could be targeted to treat such diseases.

"I suspect that this PKCδ-MARK2 pathway will ultimately be shown to be relevant not only in neurodegenerative disorders but in many other diseases including cancers," Wang says.


Stem cell in neurodegenerative disorders an emerging strategy

Ali Hassanzadeh, Department of Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran Cell Therapy and Regenerative Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.

Majid Zamani, Department of Medical Laboratory Sciences, Faculty of Allied Medicine, Gonabad University of Medical Sciences, Gonabad, Iran.

Department of Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran

Neurosciences Research Center, Tehran University of Medical Sciences, Tehran, Iran

Ali Hassanzadeh, Department of Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran Cell Therapy and Regenerative Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.

Majid Zamani, Department of Medical Laboratory Sciences, Faculty of Allied Medicine, Gonabad University of Medical Sciences, Gonabad, Iran.

Department of Tissue Engineering and Applied Cell Science, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Science, Tehran, Iran

Stem Cell Research Center, Tehran University of Medical Science, Tehran, Iran

Department of Biology, School of Basic Science, Science and Research Branch, Islamic Azad University, Tehran, Iran

Department of Prosthetic Dentistry, Sechenov First Moscow State Medical University, Moscow, Russia

School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran

Immunology Research Center (IRC), Tabriz University of Medical Sciences, Tabriz, Iran

Department of Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran

Department of Plant Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran

Department of Medical Laboratory Sciences, Faculty of Allied Medicine, Gonabad University of Medical Sciences, Gonabad, Iran

Ali Hassanzadeh, Department of Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran Cell Therapy and Regenerative Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.

Majid Zamani, Department of Medical Laboratory Sciences, Faculty of Allied Medicine, Gonabad University of Medical Sciences, Gonabad, Iran.

Department of Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran

Neurosciences Research Center, Tehran University of Medical Sciences, Tehran, Iran

Ali Hassanzadeh, Department of Applied Cell Sciences, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran Cell Therapy and Regenerative Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.

Majid Zamani, Department of Medical Laboratory Sciences, Faculty of Allied Medicine, Gonabad University of Medical Sciences, Gonabad, Iran.

Sažetak

Neurodegenerative disorders are a diversity of disorders, surrounding Alzheimer's (AD), Parkinson's (PD), Huntington's diseases (HD), and amyotrophic lateral sclerosis (ALS) accompanied by some other less common diseases generally characterized by either developed deterioration of central or peripheral nervous system structurally or functionally. Today, with the viewpoint of an increasingly aging society, the number of patients with neurodegenerative diseases and sociomedical burdens will spread intensely. During the last decade, stem cell technology has attracted great attention for treating neurodegenerative diseases worldwide because of its unique attributes. As acknowledged, there are several categories of stem cells being able to proliferate and differentiate into various cellular lineages, highlighting their significance in the context of regenerative medicine. In preclinical models, stem cell therapy using mesenchymal stem/stromal cells (MSCs), hematopoietic stem cells (HSCs), and neural progenitor or stem cells (NPCs or NSCs) along with pluripotent stem cells (PSCs)-derived neuronal cells could elicit desired therapeutic effects, enabling functional deficit rescue partially. Regardless of the noteworthy progress in our scientific awareness and understanding of stem cell biology, there still exist various challenges to defeat. In the present review, we provide a summary of the therapeutic potential of stem cells and discuss the current status and prospect of stem cell strategy in neurodegenerative diseases, in particular, AD, PD, ALS, and HD.