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"Mapping molecules to cells” - Dr. Sarah Teichmann — Transcript

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  1. 0:00up next we have uh Dr Sarah tman uh who
  2. 0:04was a distinguished leader in cell Atlas
  3. 0:06Technologies and cellular genetics Dr
  4. 0:08tman established her research group at
  5. 0:10the MRC laboratory of molecular biology
  6. 0:13in 2001 and then moved to the welcome
  7. 0:15genome campus in 2013 becoming the first
  8. 0:18faculty member appointed across both the
  9. 0:21embo European bioinformatics Institute
  10. 0:23and the welcome Sanger Institute in
  11. 0:25April 2024 Dr tman joined the University
  12. 0:28of Cambridge as chair in stem cell
  13. 0:30medicine while also working with glos
  14. 0:32Smith Klein and her startup ocell
  15. 0:35Therapeutics she co-founded the
  16. 0:37international human cell Atlas
  17. 0:39Consortium which now spans over 3,000
  18. 0:42members aiming to map all human cell
  19. 0:44types Dr tman has received numerous
  20. 0:47prestigious Awards including the embo
  21. 0:50gold medal and the febs embo women in
  22. 0:52science award and is a fellow of both
  23. 0:54the Academy of Medical sciences and the
  24. 0:56Royal Society please join me in
  25. 0:58welcoming Dr Sarah tman
  26. 1:00[Applause]
  27. 1:06thank you for that kind introduction and
  28. 1:07thank you for having me it's a
  29. 1:09tremendous honor and a pleasure to speak
  30. 1:11today in this Symposium um for the Next
  31. 1:14Generation sequence in Canada Gardner
  32. 1:16award and I want to just give a little
  33. 1:18anecdote that makes it particularly
  34. 1:20special for me to be here which is that
  35. 1:22almost exactly 30 years ago Shankar uh
  36. 1:25taught me organic chemistry When I Was
  37. 1:27An undergraduate second year
  38. 1:28undergraduate so I don't think at the
  39. 1:30time either of us thought we'd be
  40. 1:32meeting here again um but great pleasure
  41. 1:35and uh and and delighted to be here and
  42. 1:38of course Shankar went on to discover
  43. 1:40Next Generation sequencing with um David
  44. 1:44kenman and and um Dr Meyer and I went
  45. 1:48off and uh had an exciting journey
  46. 1:51through theoretical and computational
  47. 1:53biology and that's what I'm going to
  48. 1:54tell you about today um about molecules
  49. 1:58and cells so mapping cells is an idea
  50. 2:01that has a long history and has sort of
  51. 2:03probably popped up in different places
  52. 2:05in the world again and again one of the
  53. 2:08um lectures that that that um kind of is
  54. 2:11is on the internet and is famous is the
  55. 2:13the Nobel lecture by Sydney brener where
  56. 2:15he sees he says we need a program of
  57. 2:17making maps of cells and maps of how
  58. 2:20cells talk to each other the cell map
  59. 2:23project for which we don't need a model
  60. 2:25organism because of course we can study
  61. 2:27ourselves the human body um will be one
  62. 2:30of the things to occupy us for the next
  63. 2:32few decades and what Sydney didn't know
  64. 2:35was that there was going to be a
  65. 2:36resolution revolution in genomics so I
  66. 2:38don't mean next Generation sequencing
  67. 2:41but what I mean is actually the ability
  68. 2:44of a processing cells and the library
  69. 2:48preparation step Upstream that allows us
  70. 2:52to sequence the nucleic acid content of
  71. 2:54individual cells and you already heard
  72. 2:56in the the the amazing previous talk on
  73. 2:59epigenetics how important it is to
  74. 3:01understand cell States and you can see
  75. 3:03that with this technology basically it's
  76. 3:06possible um you know from from the
  77. 3:09earliest days which were sort of
  78. 3:11pioneered by azim serani and others
  79. 3:13studying a handful of cells this this
  80. 3:16technology underwent a a scaling up
  81. 3:19where it's now possible to study
  82. 3:21hundreds of thousands or millions of
  83. 3:22cells in a single experiment and so what
  84. 3:25that means is that you can take a um a
  85. 3:27tissue sample like a human heart sample
  86. 3:30and then study the the the the the
  87. 3:32individual cells or or nuclei in terms
  88. 3:35of the the transcriptomic content of the
  89. 3:38cells in other words the RNA that's
  90. 3:40that's expressed the genes that are
  91. 3:42switched on in that single cell so we've
  92. 3:44heard a lot about the DNA sequence um of
  93. 3:48of individuals in health and disease
  94. 3:51we've heard a lot about the epig genome
  95. 3:53and of course all of that is encoding
  96. 3:55the the uh repertoire of genes that are
  97. 3:58active in single cells which are very
  98. 4:00different in uh a cardiomyo side versus
  99. 4:04a um an immune cell versus a virro blast
  100. 4:07versus a neural cell Etc and so
  101. 4:10sequencing um at the single cell or
  102. 4:12single nuclear level and suspension
  103. 4:14gives us that that huge amount of
  104. 4:16information about which genes are active
  105. 4:18in each cell which we can then analyze
  106. 4:20with with computational methods deep
  107. 4:22learning AIML and so on that we have
  108. 4:25available nowadays and hand inand with
  109. 4:28that resolution Revolution
  110. 4:30what we've had is technology development
  111. 4:32in spatial genomics and spatial
  112. 4:35genomics it sort of comes through the
  113. 4:37sequencing side and the Imaging side and
  114. 4:40and sequencing and microscopy s are sort
  115. 4:42of coming together again in this spatial
  116. 4:45biology field which is kind of uh also
  117. 4:48raced forwards in the last decade or so
  118. 4:51where we can then map in a tissue
  119. 4:53section so taking a salami slice of a
  120. 4:55human tissue sample the gene expression
  121. 4:58landscape of the cells in that section
  122. 5:00and then you can imagine combining that
  123. 5:02computationally with the deep deep
  124. 5:05knowledge of the cells in that sample
  125. 5:07with consecutive sections we can build
  126. 5:10up a picture of the tissue niche in that
  127. 5:12sample in that in that tissue and
  128. 5:15understand how the cells are oriented
  129. 5:17relative to each other and this spatial
  130. 5:19biology uh you know is really um
  131. 5:23becoming kind of uh you know widespread
  132. 5:25prevalent and popular and earlier this
  133. 5:27year in June we had a small Symposium in
  134. 5:31in Stockholm called spatial biology in
  135. 5:33the genomics era and that's really the
  136. 5:35era that we live in the era that we live
  137. 5:37in now is single cell genomics and
  138. 5:39spatial genomics and and Aviv and I uh
  139. 5:42Aviv rev both gave talks in in the last
  140. 5:45section of course she's the co-founder
  141. 5:47with me um of the human cell Atlas
  142. 5:50International um uh uh project that that
  143. 5:53Rob mentioned at the beginning of the
  144. 5:54talk and so why is this
  145. 5:57mapping important why is it important to
  146. 6:00know in in in Exquisite detail and at
  147. 6:03full molecular depth um that the fine
  148. 6:06cell States in a tissue sample and how
  149. 6:09they're located relative to each other
  150. 6:11it's important because it's not just a a
  151. 6:14kind of enumeration and mapping exercise
  152. 6:16but that information also tells us about
  153. 6:19the function of the individual cells and
  154. 6:21the cell States because it tells us how
  155. 6:23the cells are talking to each other and
  156. 6:26and the the molecular dialogue basically
  157. 6:29between the cells it tells us about the
  158. 6:32cell function and and therefore then
  159. 6:34also the function of the tissue within
  160. 6:37within our organs and to illustrate that
  161. 6:40I'm going to tell you three short
  162. 6:41stories about three different tissue
  163. 6:42niches the placenta the heart and the
  164. 6:45thymus if I if I get through them so why
  165. 6:48is the placenta so fascinating um you
  166. 6:51know it's a transient organ that forms
  167. 6:53at the beginning of
  168. 6:54pregnancy and um of course it's
  169. 6:57necessary for a delivery of o oen and
  170. 6:59nutrients to the embryo what fascinated
  171. 7:02me about it is uh that that um conundrum
  172. 7:06that that Kathleen presented earlier
  173. 7:08which is that our tea cells and our
  174. 7:10immune system is trained to distinguish
  175. 7:13self from nonself and of course in the
  176. 7:15placenta just like in a tumor the the
  177. 7:18maternal immune system is presented with
  178. 7:20a paternal antigens so they should be in
  179. 7:23theory the maternal immune system should
  180. 7:25be rejecting the paternal antigens but
  181. 7:28instead what happened is that there's a
  182. 7:30a remodeling of the tissue so that you
  183. 7:33have um these larger arteries that are
  184. 7:36formed to deliver the the the oxygen
  185. 7:38nutrients through the blood to the
  186. 7:39placenta and um essentially a harmonious
  187. 7:42coexistence of the fetal cells that are
  188. 7:45the the the invasive trophoblasts that
  189. 7:46are entering the uterus and the the
  190. 7:49maternal cells on the uterine side of
  191. 7:51the placenta and Janet knows this well
  192. 7:53because she's one of the discoverers of
  193. 7:54the trophoblast stem cells so so the
  194. 7:57conundrum is really how does the
  195. 7:59maternal immune system respond and what
  196. 8:01are the interactions that allow this
  197. 8:04coexistence this peaceful coexistence
  198. 8:06and to to address that question Roser
  199. 8:08vent toror who was a postto in the group
  200. 8:10set out on this um Brave quest to do to
  201. 8:13single cell sequence um the the the the
  202. 8:17cells both on the maternal and on the
  203. 8:18fetal side of the the first trimester
  204. 8:21placenta that we got from the human
  205. 8:22developmental biology resource in
  206. 8:24Newcastle um with with the support of M
  207. 8:27hanif's lab who is right next to the war
  208. 8:29Bo there and also Ashley morph's group
  209. 8:32and this allowed us for the first time
  210. 8:33to map out the the um the fetal
  211. 8:37genotypes with the uh because M had also
  212. 8:41gotten research ethics to get the the
  213. 8:43maternal blood so we're able to use the
  214. 8:45sequencing data to say what is maternal
  215. 8:47what is fetal and distinguish maccrage
  216. 8:51States for instance that were were fetal
  217. 8:53and maccrage states that were maternal
  218. 8:55so distinguishing which cells in this
  219. 8:57intermingling come from the mother which
  220. 8:59come from the the fetus and the the this
  221. 9:04this sort of dialogue between the cells
  222. 9:06that's absolutely crucial to get right
  223. 9:08at this interface in order for the the
  224. 9:11remodeling of the the the uterus to to
  225. 9:14um allow the blood supply to to form
  226. 9:17correctly um is is an an interaction
  227. 9:20that we deciphered uh by by mapping the
  228. 9:23molecules on the surface of the cells
  229. 9:26and then statistically inferring what
  230. 9:29are the molecular interactions what's
  231. 9:31the molecular communication between the
  232. 9:34the the fetal and the maternal cells and
  233. 9:36you can see here there are three natural
  234. 9:38killer cell states that we described in
  235. 9:40in molecular detail for the first time
  236. 9:43in this sort of um
  237. 9:45um um Continuum of activation of natural
  238. 9:48killer cells and these are obviously
  239. 9:49cells that normally kill non sself so
  240. 9:52how are they kept in check they're kept
  241. 9:54in check by by the the particular um
  242. 9:58receptor ligan inter re actions that
  243. 9:59they see on the fetal side with the
  244. 10:01extrav trophoblast and from the
  245. 10:04macrofagos and strumal cells um on the
  246. 10:06maternal side that are also kind of
  247. 10:08controlling these cells and keeping them
  248. 10:10calm as it were and where does the um
  249. 10:15you know what was the thinking here
  250. 10:17behind these receptor Li interactions
  251. 10:20basically in the cells so so combining
  252. 10:23the cells with their their their
  253. 10:25molecular um uh cell surfaceome and
  254. 10:28their interactions well that's from from
  255. 10:31basically the 15 years that I spent um
  256. 10:34at the MRC laboratory of molecular
  257. 10:35biology in the structural studies
  258. 10:37division where we were studying protein
  259. 10:40biophysics and and you can see a few
  260. 10:42years ago we had a Nobel Symposium with
  261. 10:44these uh a gentleman here again in
  262. 10:47Stockholm in 2022 Demis sabis who was of
  263. 10:49course um awarded the Nobel Prize for
  264. 10:52the alpha fold and what we had worked on
  265. 10:55was
  266. 10:56um uh modeling protein complex as graphs
  267. 11:00and understanding the the assembly
  268. 11:02Pathways of proteins in three dimensions
  269. 11:05and how they find each other inside
  270. 11:07cells and also of course then what we
  271. 11:09were asking here was how do they
  272. 11:11interact with each other on the on the
  273. 11:13extracellular surface in a stoom
  274. 11:15metrically Accurate Way um with all the
  275. 11:18subunits there at the right at the right
  276. 11:20concentration so we're not thinking of
  277. 11:22protein protein interactions as binary
  278. 11:24interactions we're thinking of them
  279. 11:26basically in terms of all the subunits
  280. 11:28that were that are needed that we know
  281. 11:30from uh protein structure and protein
  282. 11:32biophysics and so it's really bringing
  283. 11:34together this molecular kind of thinking
  284. 11:37about about proteins and the cellular
  285. 11:41interactions um that that led us to a
  286. 11:43deeper understanding of of the placenta
  287. 11:46of the cell types and and um and
  288. 11:49developmental
  289. 11:50trajectories um of the the the the cell
  290. 11:53cell interactions and how that immune
  291. 11:55tolerance is set
  292. 11:57up so that's really a a story about our
  293. 12:00our development um the human development
  294. 12:03during pregnancy which is by the way
  295. 12:05different from uh uh the early kind of
  296. 12:08Developmental stages in Mouse and the
  297. 12:10and the molecules in the mouse so
  298. 12:12there's a lot of evolutionary Divergence
  299. 12:14so this concept of that Sydney brener
  300. 12:16said of not studying a model organism
  301. 12:18but studying ourselves is really quite
  302. 12:20relevant when you want to really uh uh
  303. 12:24um get to the the molecular details in
  304. 12:26the tissues the so humans are very
  305. 12:29different both in terms of the immune
  306. 12:31system in particular which is obviously
  307. 12:32evolving very fast because of host
  308. 12:35pathogen arms race but also um
  309. 12:39speciation kind of in in these early uh
  310. 12:42in these early developmental tissues so
  311. 12:45next I'm going to go on to um a a
  312. 12:47different organ that's that's uh you
  313. 12:49know um incredibly important to life
  314. 12:52which is the heart obviously one of the
  315. 12:54The crucial organs um and and one of the
  316. 12:57most complex organs in our body besides
  317. 12:59the brain and I want to talk about again
  318. 13:01tissue nichas but also cell cell
  319. 13:04interactions both in a paracrine sense
  320. 13:06but also in an endocrine sense which
  321. 13:07means signaling endocrine is the hormone
  322. 13:09system and signaling uh between distant
  323. 13:12regions of our body and coordinating our
  324. 13:14physiology so we started studying um the
  325. 13:19the human heart with collaborators in
  326. 13:20Berlin and Boston um uh many years ago
  327. 13:25and um in initially using this
  328. 13:28suspension single cell genomics
  329. 13:30Technologies to define the the the the
  330. 13:32cell types in the the free walls of the
  331. 13:35four chambers of the heart so we've got
  332. 13:36two atria two ventricles and and
  333. 13:39defining the kind of muscular tissues in
  334. 13:41terms of um both the cardiomyocytes but
  335. 13:43also the immune cells and um fiber
  336. 13:46blasts and so on that that and and and
  337. 13:48the the the complexity that we
  338. 13:50discovered was quite shocking so instead
  339. 13:52of having let's say one cardium myosite
  340. 13:54subtype in in the ventricles we found
  341. 13:57you know um six or more and um and and
  342. 14:01then more recently what we moved on to
  343. 14:04was um wanting to understand not just
  344. 14:06the muscular tissues in the heart but
  345. 14:09also the sort of brain of the heart
  346. 14:11which is the cardiac conduction system
  347. 14:13and that electrical conduction system
  348. 14:16basically maintains the coordination
  349. 14:18between the contraction of the four
  350. 14:20chambers the muscular tissue and the
  351. 14:22four chambers and that that
  352. 14:25um um uh beating of the heart that
  353. 14:29Rhythm and that coordination is kicked
  354. 14:32off by so-called pacemaker cells so
  355. 14:34pacemaker cells are very special very
  356. 14:36rare cells in our body they're amongst
  357. 14:38the only spontaneously firing cells and
  358. 14:41they they start beating very very early
  359. 14:44in embryonic development and are kept
  360. 14:45beating through a sort of clock of
  361. 14:48calcium and potassium channels that goes
  362. 14:50on forever until of course we take our
  363. 14:52last breath and the heart stops so these
  364. 14:55are absolutely crucial cells to
  365. 14:56understand they're very hard to find
  366. 14:58because they're so rich rare and the
  367. 15:00surgeon who's doing the the dissection
  368. 15:02of the tissue FR us wasn't able to see
  369. 15:04them um be also because this the tissue
  370. 15:07that they sit in the sinoatrial node is
  371. 15:08located in different positions in
  372. 15:10different people and isn't obvious uh
  373. 15:13isn't always in a perfect stereotyp
  374. 15:15typical position so we worked with a
  375. 15:17cardiac pathologist uh Professor Yen ho
  376. 15:20um in London uh and and the the um the
  377. 15:24team James cranley and kazum maak
  378. 15:26kanamaru who are both clinician
  379. 15:28scientist Tres in the group uh were were
  380. 15:31absolutely brilliant in Catching these
  381. 15:33very rare cells that you can see here in
  382. 15:35blue at the top from these are from two
  383. 15:38donor hearts that we that we um were uh
  384. 15:41lucky to to have donated uh in during
  385. 15:44the pandemic when the transplant was
  386. 15:46down in the UK um so James and kazumasa
  387. 15:50traveled to different uh cities in the
  388. 15:52UK London New Castle so on to get these
  389. 15:54declined donor hearts and then do the
  390. 15:56dissections and then send the tissue to
  391. 15:58Yen the images for looking at and
  392. 16:00identifying these regions and you can
  393. 16:02see these this tiny uh cluster of cells
  394. 16:06uh has a different profile in terms of
  395. 16:08the the sodium Channel expression that's
  396. 16:11high in these working cardiomyocytes in
  397. 16:13the uh the right atrium and um uh but
  398. 16:18but they have very high expression of
  399. 16:19this calcium channel kagna 1D which has
  400. 16:21been described from from urine cells as
  401. 16:24typical of pacemaker cells and here what
  402. 16:27you can see is the the pro profile of
  403. 16:29all ion channels and and G protein
  404. 16:31coupled receptors in cardiomyocytes and
  405. 16:34and uh neural cells um neurons and glea
  406. 16:37in the heart and you can see that these
  407. 16:39cells have a special profile that's
  408. 16:41different from the the working
  409. 16:43cardiomyocytes and the neuros cells and
  410. 16:45that gave us confidence that we had
  411. 16:46actually caught those very special cells
  412. 16:49in the human uh sinoatrial node for the
  413. 16:52first time what we did then was combined
  414. 16:54that with the spatial genomics that I
  415. 16:56mentioned and and indeed they mapped to
  416. 16:58the node to the nodal region there that
  417. 17:00you can see and and that's at the center
  418. 17:03of this uh region where um uh we see the
  419. 17:09the uh um the inner noal region with the
  420. 17:12pacemaker cells and then we Define with
  421. 17:14the spatial genomics outer noal regions
  422. 17:17that has fi blasts uh adipocytes and
  423. 17:19macrofagos that are kind of electrically
  424. 17:21insulating these cells um and we what we
  425. 17:24were also able to decipher was the the
  426. 17:26niche of the Pacemakers with with
  427. 17:29special gleo cells that we're able to
  428. 17:30Define for the first time that are kind
  429. 17:32of hugging the Pacemakers and sort of
  430. 17:35nourishing them and connecting to the
  431. 17:37sympathetic nervous system which is the
  432. 17:39uh the the parasympathetic nervous
  433. 17:41system that that comes from our our
  434. 17:43brain stem bya the cardiac ganglin to
  435. 17:45kind of keep down the heart rate and the
  436. 17:47um sympathetic nervous system which says
  437. 17:50go faster when when we see a bear and so
  438. 17:52modulates the heart rate in that way and
  439. 17:55so then um because heart rate kind of as
  440. 17:58I've indicated is so important kind of
  441. 18:00in in modulating our physiology what
  442. 18:03what um the two uh clinician scientists
  443. 18:06who are working on this James and and
  444. 18:07kazamaza kind of wanted to know is which
  445. 18:10drugs can we predict to be acting on the
  446. 18:12pacemaker cells and so I said go next
  447. 18:15door to the European biomatics Institute
  448. 18:17where there's the kemell database this
  449. 18:19is an open-source database of drugs and
  450. 18:21targets and map those developed drug to
  451. 18:25sell which they did with with Christoff
  452. 18:27palansky and and others the group and
  453. 18:29map those drugs to all the the cardiac
  454. 18:32cells including the pacemaker cells and
  455. 18:35what was what was me know not surprising
  456. 18:37was that all the chronotropic drugs have
  457. 18:40their receptors in the pacemaker cells
  458. 18:42as expected but then there are other
  459. 18:44drugs that we found acting we predict to
  460. 18:47be acting on these cells because they
  461. 18:48are receptors in the cells and the most
  462. 18:50surprising was the glip one receptor to
  463. 18:52us which is the of course the target of
  464. 18:55glip one receptor Agonist lorag stide
  465. 18:58which the wovi and asmic and Monaro and
  466. 19:01so on uh drugs and indeed if you look at
  467. 19:04the clinical uh real world evidence
  468. 19:06there's a six beats per minute increase
  469. 19:08in heart rate initially when these drugs
  470. 19:11are given so there's clinical real world
  471. 19:13evidence that these holds and we also
  472. 19:15show in vitro in experiments in the dish
  473. 19:17with fetal uh uh cardiomyocytes that you
  474. 19:20get a change in the beating pattern when
  475. 19:22you add glip one receptor agonis and
  476. 19:24recently there's been a paper from a pig
  477. 19:27uh showing the same thing and so this
  478. 19:29this allowed us to hypothesize that
  479. 19:31basically the the six beats per minute
  480. 19:33change comes through a direct mechanism
  481. 19:36on the pacemaker cells rather than an
  482. 19:38indirect mechanism via the brain or the
  483. 19:40autonomic nervous system and so this
  484. 19:43this basically gives you an idea that
  485. 19:45the human cell Atlas which is what we're
  486. 19:47contributing to here where we're
  487. 19:48building the cell atlas of the human um
  488. 19:51tissues gives us new insights not only
  489. 19:54into into signaling in the tissue Niche
  490. 19:56parine signaling but also endocrine
  491. 19:59signaling these are hormones and how
  492. 20:00hormones are acting across the body in
  493. 20:03new and unexpected ways and so that's
  494. 20:05you know also incredibly exciting so to
  495. 20:08summarize here we see the new Niche for
  496. 20:10for the cardiac conduction system with
  497. 20:12the autonomic nervous system drug to
  498. 20:14sell kind of shows us that we can use
  499. 20:16this data for Toxicology repurposing and
  500. 20:19for reconstruction of both paracrine and
  501. 20:21endocrine signals so one last story in
  502. 20:24the last few minutes is the thymus and
  503. 20:26this is relevant because of course for
  504. 20:28this prize um this year of the the gner
  505. 20:32awards there's also the car tea cells
  506. 20:34are being awarded and and te- cells
  507. 20:36develop in our thymus the thymus is a
  508. 20:39little uh uh tiny organ next to the
  509. 20:41heart was discovered as an immunological
  510. 20:43organ in the 1960s you you may or may
  511. 20:46not have heard of it it's probably one
  512. 20:47of the most recently discovered organs
  513. 20:49in the human body and the hematopics
  514. 20:51cells come to the thymus the tea cells
  515. 20:54develop and are trained to distinguish
  516. 20:56self from non-self in the organ and they
  517. 20:58they then go around and colonize the
  518. 21:00body and of course those cells also have
  519. 21:02therapeutic potential so the question
  520. 21:04with this little tiny organ which is
  521. 21:06much smaller than the heart and it
  522. 21:08actually involutes with age and becomes
  523. 21:10even even more smaller uh uh during
  524. 21:13puberty is can we map can we Atlas an
  525. 21:17entire human organ and how can we do
  526. 21:21that by combining multiple modalities
  527. 21:23together from single cell genomics
  528. 21:25spatial genomics and uh um
  529. 21:29Multiplex protein Imaging and the way we
  530. 21:32we uh figured out that we can do this is
  531. 21:35to model the organ onto a quasi uh uh
  532. 21:39sort of Two and a Half dimensional
  533. 21:41framework using a linear model from uh
  534. 21:44from from the outside to the inside of
  535. 21:46the organ and so the the the concept
  536. 21:49here is very simple we form an axis and
  537. 21:51you can think of the the the loes of the
  538. 21:54thymus like an egg that has an egg white
  539. 21:56on the outside that's the medala and an
  540. 21:58egg yellow on the in sorry that's the
  541. 22:00cortex and the egg yellow in the middle
  542. 22:03that's the medala and what we're
  543. 22:04modeling is each lobe of the thymus as
  544. 22:06an egg white sort of from the outside to
  545. 22:09the inside with a um uh a landmarks and
  546. 22:13then a nonlinear modeling between each
  547. 22:15Landmark to give us an idea of where
  548. 22:17each data point is coming from from the
  549. 22:19spatial genomics the single cell
  550. 22:21genomics and the multiplex Imaging that
  551. 22:23we did with Ron germain's group and what
  552. 22:25this allowed us to do then is to build
  553. 22:27up a model of the organ in terms of all
  554. 22:30these different layers you can think of
  555. 22:32them like layers of an onion from
  556. 22:34capsular to subcapsular through the
  557. 22:35cortex through the cortical medular
  558. 22:38Junction and into the medala which is
  559. 22:39the center of the organ and what this
  560. 22:41allowed us to discover was new insights
  561. 22:44into precisely how this um cellular
  562. 22:48development is taking place from the
  563. 22:49hematopics cells or the early thymic
  564. 22:52progenitor um that actually
  565. 22:55enters uh in inside the the organ kind
  566. 22:58of unexpectedly and then we show that it
  567. 23:00travels basically around uh up to the
  568. 23:03outside of the organ and then the cells
  569. 23:06re-enter the Medela and are trained and
  570. 23:08sort of quantifying that in a in a
  571. 23:11precise way revealed new unexpected
  572. 23:14positionings of the cells as they go on
  573. 23:17this journey of maturation through the
  574. 23:19organ what it also allows us to do is to
  575. 23:21Define precisely what the cells are
  576. 23:24seeing in terms of the extrinsic signals
  577. 23:26as they go through this journey and um
  578. 23:29they are receiving basically cyto kind
  579. 23:31signals they're receiving growth factor
  580. 23:33signals and we can we can quantify this
  581. 23:36in in terms of the different layers of
  582. 23:38the onion and what the other the
  583. 23:40epithelial cells the fiop blast and so
  584. 23:41on are expressing the dendritic cells at
  585. 23:43each layer in terms of these factors and
  586. 23:46then also show how this differs in fetal
  587. 23:49stages of thymic development so during
  588. 23:51pregnancy versus pediatric stages of
  589. 23:54thymic development when when we have the
  590. 23:56the mature organ and that's important
  591. 23:59because the te- cell output is slightly
  592. 24:01different when the during organogenesis
  593. 24:04when the thymus is forming during
  594. 24:05pregnancy and the tea cells actually
  595. 24:07contribute to development of our tissues
  596. 24:09versus after birth when we have to fend
  597. 24:11off um infections and and and other
  598. 24:15challenges so the nature of the cells
  599. 24:16kind of changes what we what we were
  600. 24:19also able to do was to map the the the
  601. 24:22the Identity or the the cell state of
  602. 24:25the cells as they then travel to
  603. 24:27peripheral organs and this is using um
  604. 24:30tissues in in um from the fetus so just
  605. 24:33to to sort of summarize we're we're
  606. 24:35understanding and mapping the t- cells
  607. 24:37across scales so we have the molecular
  608. 24:39scale with the cyto receptor
  609. 24:41interactions TCR MHC interactions which
  610. 24:43Kathleen mentioned the cellular scale
  611. 24:46understanding the developmental
  612. 24:48trajectories Cell Activation
  613. 24:49differentiation and then the whole organ
  614. 24:52scale that I described with this organ
  615. 24:53axis model um where we're we're
  616. 24:56understanding the entire lobe of the th
  617. 24:58and of course then the whole body scale
  618. 25:01is relevant in terms of immunity and
  619. 25:03tolerance and and all the functions of
  620. 25:05the immune system that I mentioned so
  621. 25:07this is unpublished work and I want to
  622. 25:09again say this has been a a really
  623. 25:11International collaboration with nadav
  624. 25:14yayan who was a postto in the group and
  625. 25:17and and also shared with John Marion's
  626. 25:19lab and VY Olman and Veronica kedley and
  627. 25:22who was an amazing PhD student in the
  628. 25:24group and this was a collaboration with
  629. 25:25Ron Germaine at the NIH and Andrea vka
  630. 25:28who did the the Ibex multiscale protein
  631. 25:30Imaging and the nanelo lab at NIH and
  632. 25:33also Tom Tagan in um Belgium and of
  633. 25:37course we we we must never forget the
  634. 25:39donors of these tissues um the women the
  635. 25:43children their families uh these tissues
  636. 25:46come from from children's hospitals and
  637. 25:48from the human developmental biology
  638. 25:50resource and um looking towards the
  639. 25:52future you can see here that that
  640. 25:55mapping the the human body across scale
  641. 25:58you know from sort of zero Dimensions
  642. 26:00where we started through two dimensions
  643. 26:03in tissue sections and then going up to
  644. 26:05large volumetric morphological
  645. 26:07reconstructions like with hierarchical
  646. 26:09phase contrast
  647. 26:11tomography you know will will give us
  648. 26:13new new insights and valuable insights
  649. 26:17um for for for a better understanding of
  650. 26:19ourselves but also for drug development
  651. 26:22drug Discovery and this multiscale
  652. 26:24modeling and mapping is enabled by by
  653. 26:28the Canadian Institute for advanced
  654. 26:30research um and and in collaboration
  655. 26:32with Gary Bader who's a co-director of
  656. 26:34mine in that program multiscale mapping
  657. 26:37um and and of course he's based here in
  658. 26:39Toronto and also kotti Bader in Indiana
  659. 26:42these are my disclosures and I will stop
  660. 26:45there say thank you and take
  661. 26:48[Applause]
  662. 26:53questions uh excellent uh thank you
  663. 26:55Sarah really uh phenomenal talk I just
  664. 26:58remind people to get your questions in
  665. 27:00uh via slido um maybe I'll I'll start
  666. 27:03with with where you ended Sarah just um
  667. 27:06you know Eric started out this morning
  668. 27:07talking about the uh ambitious journey
  669. 27:09of the Human Genome Project and and
  670. 27:11starting out with uh you know sort of a
  671. 27:13project that was hard to see through its
  672. 27:15conception and then eventually sort of
  673. 27:16working through to the point where you
  674. 27:17were doing implementation it strikes me
  675. 27:19the human cell Atlas is uh is somewhat
  676. 27:21similar in terms of that scope and
  677. 27:22ambition and so on you've presented a
  678. 27:24few uh cases here of really really
  679. 27:26impressive work we also uh you know
  680. 27:28mentioned that there's collaborators
  681. 27:30working in other spaces around the world
  682. 27:31in the Consortium and so on can we just
  683. 27:33say a few words about kind of how the
  684. 27:35human cell Outlets is sort of look
  685. 27:36coming together more broadly in terms of
  686. 27:38international collaboration where it is
  687. 27:40on the journey and maybe what some of
  688. 27:41the hurdles remain to kind of see it to
  689. 27:43fruition absolutely no so thank you
  690. 27:45that's uh be delighted to do that so the
  691. 27:47human cell Atlas is this gr Grassroots
  692. 27:50International Consortium that you
  693. 27:51mentioned has over 3,000 members from
  694. 27:53over 100 countries around the globe and
  695. 27:56everyone is welcome to join it and there
  696. 27:58are a lot of members here in Canada that
  697. 28:00contributing I've already mentioned Gary
  698. 28:02but there are there are many others
  699. 28:03Sonia mcparland you know who have been
  700. 28:05atlasing the liver so this is really
  701. 28:07Grassroots and um there's more
  702. 28:09information at hum cals.org
  703. 28:12jooin HCA where you everybody can join
  704. 28:15and register who's interested in this
  705. 28:17quest of mapping the human body at the
  706. 28:19molecular and cellular level and the the
  707. 28:22project has is is sort of organized into
  708. 28:25working groups and and biological
  709. 28:26networks bi ological networks focus on
  710. 28:29the individual organs and systems in the
  711. 28:31body and we've generated over 100
  712. 28:33million suspension cell data points and
  713. 28:36increasing um spatial data is coming
  714. 28:40through and we're basically in the phase
  715. 28:43of now assembling data objects for
  716. 28:45suspension cell data sets for individual
  717. 28:47tissues and organs and we're releasing
  718. 28:50sort of gold standard uh data sets now
  719. 28:53on the human cell Atlas data. human cell
  720. 28:56at.org website so you can kind of think
  721. 28:58of that as like the golden path assembly
  722. 29:01of the chromosomes of the Human Genome
  723. 29:02Project at least in a first draft and
  724. 29:05that's focused on suspension not spatial
  725. 29:07data we are we are so so we're sort of
  726. 29:09developing these first drafts now
  727. 29:11there's going to be a big publication
  728. 29:13bundle at natur publishing group at the
  729. 29:15end of November and we are then looking
  730. 29:17forward to kind of the next phase of the
  731. 29:19project which will be a lot um I hope
  732. 29:22more comprehensive coverage of the body
  733. 29:24and and much more um uh High resolute
  734. 29:28spatial genomics data coverage of all
  735. 29:30the tissues so that's how I see it going
  736. 29:33yeah awesome yeah really exciting uh
  737. 29:36initiative uh I think we have time for
  738. 29:37one question here from the audience and
  739. 29:39so um this is uh asking you to comment
  740. 29:42on the implications of your work with
  741. 29:43placenta and immune tolerance and the
  742. 29:46potential for uh treatments of
  743. 29:48autoimmune
  744. 29:51diseases potential for treatments of
  745. 29:53autoimmune diseases
  746. 29:55um I mean I would say the mo and
  747. 29:58mechanistic level a lot of the
  748. 30:00tolerogenic interactions like pd1 pdl1
  749. 30:03and so on were were you know can be
  750. 30:05observed in the placenta so I showed
  751. 30:07with enk cells like entpd1 which is the
  752. 30:10enzyme that degrades ATP it breaks down
  753. 30:13ATP and so on a lot of those at the
  754. 30:15molecular level there are
  755. 30:17tolerogenic kind of mechanisms that that
  756. 30:20may be relevant in autoimmunity but
  757. 30:23they're probably sort of deployed in a
  758. 30:25you know they may be deployed in a
  759. 30:27different way in different cells and
  760. 30:29different sort of tissue niches in
  761. 30:31autoimmunity but yeah it's a um at the
  762. 30:33molecular level there are a lot of
  763. 30:35mechanisms that are that are repeated
  764. 30:37again and again in different parts of
  765. 30:38the body in different contexts excellent
  766. 30:41well thank you very much please join me
  767. 30:42in thanking Dr s tman for her wonderful
  768. 30:45CL

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