{"id":6273,"date":"2026-10-19T09:48:42","date_gmt":"2026-10-19T09:48:42","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-anna-karen-sigurdardottir\/"},"modified":"2026-10-19T09:48:42","modified_gmt":"2026-10-19T09:48:42","slug":"doktorsvorn-i-lif-og-laeknavisindum-anna-karen-sigurdardottir","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-anna-karen-sigurdardottir\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed l\u00edf- og l\u00e6knav\u00edsindum – Anna Karen Sigur\u00f0ard\u00f3ttir"},"content":{"rendered":"
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Fimmtudaginn 9. j\u00fan\u00ed ver Anna Karen Sigur\u00f0ard\u00f3ttir doktorsritger\u00f0 s\u00edna \u00ed l\u00edf- og l\u00e6knav\u00edsindum vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0:\u00a0Hlutverk non-coding RNA og peroxidasins \u00ed frumus\u00e9rh\u00e6fingu og grein\u00f3ttri formger\u00f0 \u00ed brj\u00f3stafrumul\u00ednu me\u00f0 stofnfrumueiginleika.\u00a0The role of non-coding RNA and peroxidasin in breast epithelial progenitor cell plasticity and differentiation.<\/strong><\/p>\n

Andm\u00e6lendur eru dr. Ren\u00e9 Villadsen, d\u00f3sent vi\u00f0 Kaupmannahafnarh\u00e1sk\u00f3la, og dr. \u00de\u00f3runn Rafnar, forst\u00f6\u00f0uma\u00f0ur hj\u00e1 \u00cdE.<\/p>\n

Umsj\u00f3narkennari var \u00de\u00f3rarinn Gu\u00f0j\u00f3nsson, pr\u00f3fessor og lei\u00f0beinandi var Gunnhildur \u00c1sta Traustad\u00f3ttir, a\u00f0junkt. Auk \u00feeirra s\u00e1tu \u00ed doktorsnefnd Bylgja Hilmarsd\u00f3ttir, sameindal\u00edffr\u00e6\u00f0ingur, Eir\u00edkur Briem, deildarstj\u00f3ri erf\u00f0a-og sameindal\u00e6knisfr\u00e6\u00f0ideildar \u00e1 LSH, J\u00f3n \u00de\u00f3r Berg\u00fe\u00f3rsson, lektor, og Sigr\u00ed\u00f0ur Valgeirsd\u00f3ttir, l\u00edffr\u00e6\u00f0ingur.<\/p>\n

S\u00e6d\u00eds S\u00e6varsd\u00f3ttir, pr\u00f3fessor og varadeildarforseti L\u00e6knadeildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 13:00.<\/p>\n

V\u00f6rninni ver\u00f0ur streymt:<\/p>\n

https:\/\/livestream.com\/hi\/doktorsvornannakarensigurdardottir<\/a><\/p>\n

\u00c1grip<\/strong><\/p>\n

Brj\u00f3stkirtillinn er grein\u00f3tt l\u00edff\u00e6ri sem samanstendur af tv\u00edskiptri \u00feekju af kirtil- og v\u00f6\u00f0va\u00feekjufrumum. Grein\u00f3tt formger\u00f0 er grunnferli \u00ed \u00feroska brj\u00f3stkirtilsins en a\u00f0 stj\u00f3rnun hennar koma fj\u00f6lmargir \u00fe\u00e6ttir sem m.a. hafa \u00e1hrif \u00e1 frumus\u00e9rh\u00e6fingu og bandvefsumbreytingu (EMT) \u00feekjunnar. Markmi\u00f0i\u00f0 me\u00f0 doktorsverkefninu var a\u00f0 sko\u00f0a hlutverk non-coding RNA (ncRNA) sameindanna miR-203a og MEG3 og pr\u00f3teinsins peroxidasins (PXDN) \u00ed grein\u00f3ttri formger\u00f0, EMT og frumus\u00e9rh\u00e6fingu og nota til \u00feess D492 frumum\u00f3deli\u00f0. D492 myndar grein\u00f3ttar \u00feyrpingar \u00ed \u00fer\u00edv\u00ed\u00f0ri r\u00e6kt en me\u00f0 samsvarandi bandvefsfrumul\u00ednu, D492M, er einnig h\u00e6gt a\u00f0 nota frumum\u00f3deli\u00f0 vi\u00f0 ranns\u00f3knir \u00e1 EMT.<\/p>\n

Helstu ni\u00f0urst\u00f6\u00f0ur s\u00fdndu a\u00f0 tj\u00e1ning miR-203a j\u00f3kst \u00ed samr\u00e6mi vi\u00f0 myndun grein\u00f3ttrar formger\u00f0ar, a\u00f0 tj\u00e1ning miR-203a var l\u00edtil sem engin \u00ed D492M mi\u00f0a\u00f0 vi\u00f0 D492 en yfirtj\u00e1ning \u00e1 miR-203a \u00ed D492M leiddi a\u00f0 hluta til vi\u00f0sn\u00fanings \u00e1 bandvefsumbreytingu. Einnig var sta\u00f0fest a\u00f0 PXDN er markgen miR-203a sem binst vi\u00f0 bindiset \u00e1 3\u2018UTR pr\u00f3teinsins og veldur \u00fear me\u00f0 ni\u00f0urtj\u00e1ningu. Yfirtj\u00e1ning \u00e1 PXDN \u00ed D492 s\u00fdndi a\u00f0 pr\u00f3teini\u00f0 \u00fdtti undir \u00f3s\u00e9rh\u00e6f\u00f0a basal svipger\u00f0 og dr\u00f3 um lei\u00f0 \u00far kirtil- og v\u00f6\u00f0va\u00feekjus\u00e9rh\u00e6fingu, sem leiddi til hindrunar \u00e1 myndun grein\u00f3ttrar formger\u00f0ar. Jafnframt kom fram aukin tj\u00e1ning \u00e1 umritunar\u00fe\u00e6ttinum p63, sem \u00feekkt er a\u00f0 vi\u00f0heldur basal svipger\u00f0 \u00ed brj\u00f3sta\u00feekju. RNA ra\u00f0greining s\u00fdndi a\u00f0 gen sem taka \u00fe\u00e1tt \u00ed ferlum tengdum s\u00e9rh\u00e6fingu og \u00feroskun \u00feekjuvefja voru me\u00f0 aukna tj\u00e1ningu en a\u00f0 sama skapi var virkni \u00ed bandvefsumbreytingu verulega skert. Ni\u00f0urst\u00f6\u00f0ur ranns\u00f3knarinnar s\u00fdndu fram \u00e1 \u00e1\u00f0ur \u00f3\u00feekkt hlutverk PXDN \u00ed frumus\u00e9rh\u00e6fingu \u00ed brj\u00f3stkirtlinum en geni\u00f0 haf\u00f0i fram til \u00feessa ekki veri\u00f0 sko\u00f0a\u00f0 \u00ed \u00feessu tilliti. A\u00f0 lokum var hlutverk lncRNA sameindarinnar MEG3 sko\u00f0a\u00f0 en \u00fear kom \u00ed lj\u00f3s a\u00f0 MEG3 er bundi\u00f0 vi\u00f0 bandvefsl\u00edka svipger\u00f0 en tj\u00e1ning \u00feess var markt\u00e6kt h\u00e6rri \u00ed bandvefsl\u00edkum frumul\u00ednum mi\u00f0a\u00f0 vi\u00f0 \u00feekjufrumul\u00ednur.<\/p>\n

English abstract<\/strong><\/p>\n

The mammary gland is a branched organ comprised of terminal duct lobular units (TDLUs) that contain bilayered epithelium of inner luminal cells and outer myoepithelial cells. Branching morphogenesis is a central element in mammary gland development that is controlled by a myriad of factors that influence cell differentiation and epithelial-to-mesenchymal transition (EMT) in the epithelium. The aim of the project was to apply the D492 breast epithelial cell model to investigate the role of non-coding RNAs (ncRNA) miR-203a and MEG3 and the peroxidasin (PXDN) protein in branching morphogenesis, EMT and epithelial cell differentiation. D492 cells form branching colonies in 3D-culture and can, along with its mesenchymal derivative cell line D492M, be applied to study EMT.<\/p>\n

We demonstrated that miR-203a expression is increased during branching with increased colony complexity and cell differentiation. Furthermore, miR-203a was significantly less expressed in D492M compared to D492. Overexpression of miR-203a in D492M lead to partial mesenchymal-to-epithelial transition (MET). We confirmed that miR-203a targets the 3\u2018UTR of PXDN, resulting in post-transcriptional downregulation. Overexpression of PXDN in D492 eliminated the luminal and myoepithelial phenotype while inducing undifferentiated basal phenotype, thereby negatively affecting plasticity that is characteristic for the D492 cell line. This led to complete inhibition of branching morphogenesis. Furthermore, RNA-sequencing reveals significant enrichment in pathways involved in epithelial differentiation and development in D492PXDN while EMT is significantly downregulated. Finally, the role of the lncRNA MEG3 in EMT and epithelial differentiation in D492 and D492M was explored. Results showed that MEG3 expression was associated with mesenchymal phenotype and was significantly higher in mesenchymal cell lines.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Anna Karen Sigur\u00f0ard\u00f3ttir er f\u00e6dd \u00e1ri\u00f0 1987 \u00ed Reykjav\u00edk. H\u00fan lauk B.Sc. gr\u00e1\u00f0u \u00ed d\u00fdral\u00e6kningum fr\u00e1 Heilbrig\u00f0isv\u00edsindasvi\u00f0i Kaupmannahafnarh\u00e1sk\u00f3la \u00e1ri\u00f0 2012 og kand\u00eddatspr\u00f3fi fr\u00e1 s\u00f6mu deild \u00e1ri\u00f0 2015. Anna Karen h\u00f3f doktorsn\u00e1m vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2017 og sinnti stundakennslu \u00ed verklegri vefjafr\u00e6\u00f0i me\u00f0fram n\u00e1mi en starfar n\u00fa sem d\u00fdral\u00e6knir \u00e1 meinafr\u00e6\u00f0ideild Keldna. Anna Karen er gift Einari Oddi Sigur\u00f0ssyni h\u00e9ra\u00f0sd\u00f3msl\u00f6gmanni og eiga \u00feau tv\u00f6 b\u00f6rn, El\u00ednu Sigurbj\u00f6rt og Erni Ingimar. Foreldrar hennar eru Sigur\u00f0ur Halld\u00f3r J\u00f3hannsson og Brynd\u00eds Arnfinnsd\u00f3ttir.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5128,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2022-06-09T13:00:00+00:00","_phd_date_end":"2022-06-09T16:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Hlutverk non-coding RNA og peroxidasins \u00ed frumus\u00e9rh\u00e6fingu og grein\u00f3ttri formger\u00f0 \u00ed brj\u00f3stafrumul\u00ednu me\u00f0 stofnfrumueiginleika. 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