Wykład I

Waskulogeneza i angiogeneza –wprowadzenie

Circulatory system and blood vessels

Blood vessels Blood vessels

Cleaver O & Melton DA, Nature Med., June 2003

Three ways of formation of blood vessels Three ways of formation of blood vessels

Vasculogenesiscapillaries are formed from

vascular progenitor cells

bFGF

VEGFangioblast capillary

Angiogenesis formation of new blood vessels from pre-existing vessels

VEGF, Ang-2

Arteriogenesisformation of mature blood vessels; differentiation into

veins and arteries

Ang1, bFGF, MCP-1, PDGF

Genes and receptors involved in different stages Genes and receptors involved in different stages of blood vessel formation of blood vessel formation

Vasculogenesis

Live zebrafish (Danio rerio) embryos 4 days after fertilization, with those in the middle ring stained for hemoglobin to detect blood cells. Zebrafish studies have advanced our understanding of heart and blood development. [Image: Alan J. Davidson]

Hematopoiesis in zebrafish (Danio rerio)

Formation of a vascular network

Morphological differentiation of endothelial cells Morphological differentiation of endothelial cells

Skeletal muscle, heart,lung, brain

Endocrine and exocrine organsintestinal villi

Cleaver O & Melton DA, Nature Med., June 2003

Vessel wall assembly

Cleaver O & Melton DA, Nature Med. June 2003

Conway, Carmeliet & Collen, 2001

Komórki śródbłonka i mięśni gładkich ściany naczynia powstają z różnych komórek macierzystych

Hemangioblast

Angioblast

Sródbłonek Sródbłonek żylny tętniczy

VEGF

Naczyniowa komórka

macierzysta

VEGF

PDGF-BBPericyty/mięśnie gładkie

Komórki macierzyste mięśni gładkich (kilka typów)

Komórki krwimięśnie szkieletowe

PDGF-BB

PrePre-- and and postpost--natal origin of mural cells natal origin of mural cells

Jain R, Nature Med. June 2003

Rodzaje Rodzaje angiogenezy angiogenezy w rozwoju embrionalnymw rozwoju embrionalnym

1. Rozgałęzianie – sprouting – w zarodkowym mózgu2. Dzielenie – bridging 3. Wrastanie – intussusceptive growth – np. w zarodkowych płucach

Powstawanie naczyń krwionośnych w rozwoju embrionalnymPowstawanie naczyń krwionośnych w rozwoju embrionalnym

Carmeliet, Nature Med. 2000

Formation of blood vessels in adultsFormation of blood vessels in adults

Carmeliet, Nature Med. 2000

The wellThe well--tempered vessels tempered vessels

Blau HM & Banfi A, Nature Med 2001;7:532-534

VEGFPDGF-BBAng-1Ang-2HIF-1αPR39

Vessel maintainance versus vessel regression Vessel maintainance versus vessel regression

Budowa naczyń krwionośnych i limfatycznych Budowa naczyń krwionośnych i limfatycznych

large vessel

Jain R, Nature Med. June 2003

Etapy Etapy angiogenezy angiogenezy zwiększenie przepuszczalności ściany i odkładanie włóknikarozluźnienie warstwy komórek wspomagających (pericytów) uwolnienie proteinaz przez komórki śródbłonka trawienie błony podstawnej i macierzy pozakomórkowej otaczającej

naczynie krwionośnemigracja i proliferacja komórek śródbłonkatworzenie struktur naczyniowych łączenie (fuzja) nowych naczyńinicjacja przepływu krwi

- zahamowanie proliferacji komórek śródbłonka - zahamowanie migracji komórek śródbłonka

synteza błony podstawnej

Endothelial cells

-one of the most quiescent and genetically stable cells of the body –turnover time is usually hundred of days

-proliferation is inhibited due to the contact with the capillary basement membrane

Endoglin is an auxiliary receptor for the transforming growth factor-beta family of cytokines and is required for angiogenesis and heart development.

Błona podstawna(basement membrane)

Wyspecjalizowana postać macierzy pozakomórkowej

Basement membrane in various organs

-kolagen IV -kolagen XV-kolagen XVIII- laminin - heparan-sulphate proteoglycans- perlecans - nidogen/entactin -SPARC/BM-40/osteopontin

Błona podstawna naczyńkrwionośnych

Enzymy proteolityczne

Proteinazy serynowe(aktywatory plazminogenu)

Metaloproteinazy (MMPs)

Inhibitory metaloproteinaz (TIMPs)

Differentiation of endothelial cells Differentiation of endothelial cells on on basement membrane basement membrane

Physiological and pathological angiogenesis Physiological and pathological angiogenesis

Physiological angiogenesis in adults is restricted Physiological angiogenesis in adults is restricted

placenta uterus

Hair growth Wound healing

Stages of hair growth

Anagen - active growth and hair proliferation –- enhanced angiogenesis (proliferation of endothelial cells) –effect of VEGF

Catagen – apoptosis of endothelial cellsinvolution of hair follicles – effect of thrombospondin 1

Telogen – resting phase

Angiogenesis during murine hair cycle Angiogenesis during murine hair cycle

Yano et al., JCI 107: 409-417, 2001

Anagen Anagen Anagen

Upregulation of VEGF during the anagen growth phase

Blockadge of VEGF activity inhibits hair growth

„Remodelling type” of angiogenesis during hair growth

Enhanced hair growth and follicle size in VEGF transgenic mice

- hair re-growth after depilation accelerated, - hair more dense

Thrombospondin-1 plays a critical role in the induction of hair follicle involution and vascular regression during the catagen phase.

Yano K, Brown LF, Lawler J, Miyakawa T, Detmar M.

Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.

Hair growth is associated with pronounced vascular-endothelial-growth-factor-induced perifollicular angiogenesis, whereas the catagen regression phase is characterized byapoptosis-driven blood vessel regression. The biologic relevance of endogenous inhibitors of angiogenesis in the control of hair cycling, however, has remained unknown. We studied the expression and biologic role of the angiogenesis inhibitorthrombospondin-1 (TSP-1) during the induced adult hair follicle cycle in wild-type, TSP-1 deficient, and TSP-1 overexpressing transgenic mice. TSP-1 expression wasabsent from hair bulb and dermal papilla cells during early to mid-anagen but washighly upregulated throughout the catagen involution phase. In TSP-1 deficient mice,the follicle growth phase was significantly prolonged, associated with increased perifollicular vascularization and vascular proliferation. Conversely, hair follicle growthwas delayed in K14/TSP-1 transgenic mice that expressed high levels of TSP-1 in outer root sheath keratinocytes, associated with reduced perifollicular vascularization. These effects were most probably mediated via its antiangiogenic effects because TSP-1 didnot affect the growth of cultured murine vibrissae in the absence of a functional vascular system. These results identify a critical role of TSP-1 in the induction of anagen follicle involution, with potential implications for the therapeutic modulation of

J Invest Dermatol 2003 Jaqn 120L 14-19

hair follicle growth.

Vascular remodeling in the Vascular remodeling in the ratrat ovary ovary

1 – small vesicular follicle 2 – large preovulatory follicle3 – developing corpus luteum

(~ 8 hours after ovulation)4 - non-productive follicle

undergoing atretic regression

Maisonpierre et al, Science 277: 55-60, 1997

Vascular remodeling in the Vascular remodeling in the ratrat ovary ovary

Comparison of angiopoietin and VEGF RNA expression patterns during vascular remodeling in the ovary. Ovaries from hormone-induced ovulating rats (29) were serially sectioned and adjacent 8-µm sections were hybridized to the indicated probes. Sections correspond to three successive developmental stages: a small vesicular follicle (column 1), a large preovulatory follicle (column 2), and a developing corpus luteum ~8 hours after ovulation (column 3). Also shown is a nonproductive follicle undergoing atretic regression (column 4). (A) Schematic summary of the RNA expression patterns relative to the known disposition of the vasculature (red) during the various stages of follicular development and atresia. VEGF, yellow; Ang1, green; Ang2, large black dots in late preovulatory follicle and corpus luteum (columns 2 and3) and solid black region in atretic follicle (column 4). (B) Corresponding bright-field images of each developmental stage. (C to E) Dark-field images of sections probed for transcripts ofVEGF (C), Ang2 (D), or Ang1 (E). In situ hybridizations were performed as in (13), using probes as described (28). Scale bar, 100 µm (all micrographs).

New capillary formation in response to wounding

Angiogenic mediators Angiogenic mediators

Diseases characterized or caused by insuffienct angiogenesis or vessel regression