Damage to our tissues occurs daily and must be repaired by the body in a timely manner in order to prevent infection and restore tissue integrity. Many cell types are involved in the healing process, but it is the cells of the stroma that are largely responsible for rebuilding fibrous tissue, which provides structure and support for all other cell types during healing. This dissertation focuses on stromal tissue repair, the rebuilding of fibrous tissue by fibroblasts following injury. Specifically, I focus on 1) models to study wound healing in vitro, and the specific biological processes of healing that each model captures, 2) the response of engineered stromal microtissues to different methods of injury, namely laceration and laser ablation, and the subsequent clearance and rebuilding of the extracellular matrix by fibroblasts, and 3) how different types of stromal cells and extracellular matrix proteins contribute to tissue repair in vitro.

The cardiovascular system of Drosophila melanogaster consists of a cardiac tube composed of myogenic cardiomyocytes and associating non-contractile pericardial cells, pumping hemolymph into the open circulatory system. The cardiac tube, known as the dorsal vessel, is embedded in a highly regulated extracellular matrix environment, required to maintain cellular integrity and cardiac function. After embryogenesis, the dorsal vessel undergoes extensive physiological changes, relying on the extracellular matrix to adapt and remodel accordingly. Three extracellular matrix proteins are investigated throughout this thesis: Type IV Collagen, Laminin and Pericardin. Due to their localization, morphology, and role in early development, the pericardial cells are candidate cells responsible for dorsal vessel extracellular matrix deposition and regulation throughout post-embryonic growth. Using immunofluorescence techniques in combination with confocal microscopy, I characterize the association between pericardial cells and extracellular matrix proteins, and quantify extracellular matrix protein deposition at the dorsal vessel throughout post-embryonic development. Gene knock-down experiments assess pericardial cell contribution to extracellular matrix synthesis and deposition at the dorsal vessel in third instar larva. Moreover, I quantify extracellular matrix protein deposition at the dorsal vessel in the absence of pericardial cells. These data suggests that pericardial cells regulate extracellular matrix protein deposition, localization and contribute to proper cardiac morphology in post-embryonic development. / Thesis / Master of Science (MSc)

Cardiovascular disease is a leading cause of morbidity worldwide. Many cardiomyopathies and developmental defects arise from misregulation of the cardiac extracellular matrix (ECM), a dynamic network of proteins, growth factors, and signaling molecules that form a protective sheath around organs and tissues. Changes in ECM composition are mediated in part by matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs). ECM dysregulation leads to outcomes such as fibrotic scarring, hypertrophy, and myocardial infarction. Although fundamental to heart formation and function, the regulation of ECM integration and remodeling during growth is poorly understood. To investigate this, I developed a novel adaptation of fluorescence recovery after photobleaching (FRAP), which, for the first time, allows us to assess ECM protein incorporation during growth in live, intact Drosophila larvae. As such, recovery of fluorescently tagged proteins is a proxy for addition or relocation of ECM protein. We focus on Collagen IV (Viking), a conserved protein and major constituent of the basement membrane (BM). Integration and stabilization of Collagen IV in the BM is poorly understood, however is known to be mediated in part by Collagen modifying proteins secreted protein acidic and rich in cysteine (SPARC) and lysyl oxidase (Lox) are known. We established a time course for Vkg-GFP fluorescence accretion in the heart and body wall muscle throughout larval development, under normal conditions and those in which mmp2 or timp is overexpressed. We also observed the effects reducing the activity of SPARC and Lox Vkg dynamics in the early third instar cardiac ECM. In wildtype, we report a strong phasic pattern of Vkg accumulation at second to third instar ecdysis, potentially to support growth of the succeeding instar. Heart-specific overexpression of mmp2 and timp, the inhibitor of mmp2, perturbs net fluorescence recovery as well as estimated turnover of Vkg-GFP. Our results suggests that MMPs are positive regulators of Vkg/Col IV turnover in the ECM, which is in alignment with other recent studies (Davis et al., 2022; Töpfer et al., 2022). Loss of SPARC and Lox appears to affect estimated Vkg turnover in the cardiac ECM, consistent with a role for these proteins in integrating and stabilizing Collagen IV in the BM. These findings have implications in cardiac conditions and in other ECM-related disorders and diseases such as connective tissue disorders, muscular dystrophy, fibrosis, and cancer. / Thesis / Doctor of Science (PhD)

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24835号 / 医博第5003号 / 新制||医||1068(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 浅野, 雅秀, 教授 柳田, 素子, 教授 近藤, 玄 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The extracellular matrix (ECM) of the aorta is a complex meshwork of elastin, collagen, and glycosaminoglycans (GAG). It also modulates the mechanical properties of the aorta, which in turn dictate lethal ruptures such as those caused by aneurysm and dissection. Amongst other roles, aortic stiffness controls the aorta’s ability to expand and recoil, and residual stresses, which are those existing in the absence of load, affect the magnitude and distribution of the mechanical stresses throughout the aortic wall. Mechanical stresses can be predicted via complex computer models, powerful tools that can also provide insight regarding the risk of rupture, given that ruptures occur when the mechanical stresses exceed the strength of the aorta. While this dissertation is primarily focused on the effect of GAG on residual stresses, other ECM (collagen, elastin) and mechanical (stiffness) factors are considered to expand our understanding of the structure-mechanics relationship in the aorta. This is important because the ECM undergoes extensive remodelling during aging and disease, but it is also critically important, as mentioned, in the context of aortic rupture. We first explored the mechanical roles of GAG in a finite element model by studying both the transmural residual stresses and the opening angle (an indicator of circumferential residual stresses) in ascending (AS) aortic ring models. Both were shown to be modulated by the GAG content, gradient, and the nature of the transmural distribution. While a heterogeneous GAG distribution led to the development of residual stresses which could be released by a radial cut, this was not the case when a homogeneous distribution was prescribed. Because the GAG distributions used in the first study were based on assumptions, and to get an in vitro understanding of the ECM role in modulating residual stresses, biomechanical mechanisms were explored in thoracic aortas from 5- to 6-month-old pigs. In a second study, we generated new detailed data on the distributions of collagen, elastin and GAG, throughout the aortic wall in the AS, arch (AR), and descending thoracic (DT) regions, and established correlations between the ECM constituents and the opening angle. The strongest correlations were observed between the opening angle and the total collagen:GAG ratio as well as the total GAG content. In line with our first in silico work, this in vitro investigation revealed that the GAG content and gradient modulate circumferential residual stresses and suggested that the interaction between GAG and the ECM fibers also plays a role in regulating residual stresses. In a third study, we examined the extent of contribution of GAG to circumferential residual stresses and to the radial compressive stiffness of the aortic wall, as well as the underlying mechanism through which GAG contribute to the mechanical properties using enzymatic GAG depletion. GAG depletion was associated with a decrease in the opening angle, by approximately 25%, 32%, 42% in the AS, AR, and lower DT regions respectively, and an increase in the radial compressive stiffness of the AS aorta. Glycation was also associated with a decrease in the opening angle, in which GAG depletion also had a similar effect. A small loss of water content was detected after GAG depletion, and the AS region was also associated with a significant loss of compressive deformation in the inner layer of the aorta following GAG depletion, suggesting that GAG interact with ECM fibers in their effect on aortic mechanics. The garnered experimental geometrical data and intramural GAG distributions were finally used to simulate animal-specific aortic rings from the AS, AR, and DT regions. The opening angle response was evaluated in solid matrices assuming one layer, and two layers to capture the different mechanical behaviors of the intima-media and the adventitia. A Holmes-Mow constitutive relationship was used and material parameters were obtained by curve fitting experimental stress-strain curves obtained from biaxial tests. Numerical results were evaluated by comparing simulated and experimental opening angles, revealing a notable overall agreement between the two.

The extracellular matrix (ECM) is the highly hydrated, protein- and glycosaminoglycan- (GAG) based cell environment that provides cell-instructive cues like the mechanical stabilization of the cells and transmission of biochemical and physical signals. To biochemically and mechanically mimic the ECM, hydrogels with the highly negatively charged GAG heparin in interplay with a stabilizing polymer network are of high interest in biomaterial engineering. The application as cell-instructive materials allows for controlling transport processes of signaling molecules within the matrices, cell growth and differentiation behavior, and cellular fate decisions. In particular, heparin-based biomaterials enable targeted sequestration of signaling molecules on the one hand, but also sustained delivery of them with a lower necessary amount to be used, in contrast to the discontinuous application of solutes. In addition, heparin-based biomaterials can protect the loaded cargo from enzymatic degradation and conformational changes.[1]–[3] The affinity to signaling molecules as key feature provides the potential for applications in wound healing and tissue regeneration. Synthetic sulfonated polymers (SSPs) as synthetic heparin analogs can address multiple drawbacks of native heparin, such as its heterogeneous chemical structure and the potential risk of viral contamination from the animal isolation source.[4],[5] Due to a large number of molecular design opportunities in particular the degree of sulfation, sulfate volume concentration, sulfate or sulfonate nature, distance of the sulf(on)ate from the backbone, and hydrophobicity of the polymers, biochemical processes may be controlled in a targeted manner. The chemical possibilities for forming a hydrogel network based on SSPs are far more diverse with synthetic, freely designable polymers to achieve a targeted structure and chemical nature of the network. Here, the aim was to introduce a library of SSPs to replace heparin in fully synthetic hydrogels capable of modulating cell-instructive cues such as soluble factor signaling, adhesiveness, and growth behavior of integrated cells. Accordingly, a library of systematically varied SSPs differing in degree of sulfation, sulfate or sulfonate conjugation, hydrophobicity, and sulf(on)ate distance to the backbone have been synthesized from by polymer analog reaction of various sulf(on)ated amines with a polyacrylate (15 kDa, sodium salt) as the polymeric backbone. The polymers have been thoroughly characterized by proton nuclear magnetic resonance (1H-NMR), Fourier-transform infrared spectroscopy (FTIR), asymmetric flow field flow fractionation (AF4) coupled light scattering analysis, and microscale thermophoresis (MST) for their molecular composition, stability in aqueous solution, conformation, and interaction with a chosen signal molecule. The affinity of the very stable coiled polymers under physiological conditions to signaling molecules depends mainly on the degree of sulfation, sulfate or sulfonate nature, and hydrophobicity. The SSPs are crosslinked with 4-arm star-shaped poly(ethylene glycol) (starPEG) either directly to form amide-crosslinked hydrogels or by pre-functionalization via Michael-type addition to prepare cell-instructive hydrogels, each with graded mechanical properties. The affinity of these hydrogels for various signaling molecules can be quantified compared to heparin-based ones and attributed to the influence of the degree of sulfation, sulfate volume concentration, sulfate or sulfonate nature, and hydrophobicity. The potential of SSPs in functional 3D tissue cultures could be confirmed by renal morphogenesis and neural network formation in the corresponding hydrogels by collaborators. Further on, the synthesis procedure of hydrogel precursors has been transferred to fully automated procedures. Because standardized production of cell-instructive hydrogels at low compositional and batch-to-batch variation and material compliance can benefit from high-throughput synthesis and liquid handling robots. An automated multistage workflow was developed to synthesize hydrogel precursors, carry out hydrogel formation, and execute cell culture experiments with cells embedded in the hydrogels. The protocol combines two robotic liquid handling systems and a microscope for automated sample imaging and cell analysis. The customized heparin and SSP maleimidation procedures, including temperature-regulated synthesis, purification, and aliquotation, were implemented on a customized liquid-handling robot. The resulting hydrogel precursors were analyzed for their maleimide conjugation efficiency and purity by 1H-NMR and conductivity measurements and for their hydrogel formation ability. This automated synthesis can ensure the quality and production of good manufacturing practice (GMP)-compliant hydrogel materials. Automated SSP hydrogel preparation, cell culture, and analysis can further promote combinatorial approaches to biomedical applications of cell-instructive materials. References [1] Lohmann, N.; Schirmer, L.; Atallah, P.; Wandel, E.; Ferrer, R. A.; Werner, C et al. Glycosaminoglycan-Based Hydrogels Capture Inflammatory Chemokines and Rescue Defective Wound Healing in Mice. Sci. Transl. Med. 2017, 9 (386), 1–12. [2] Schirmer, L.; Atallah, P.; Werner, C.; Freudenberg, U. StarPEG-Heparin Hydrogels to Protect and Sustainably Deliver IL-4. Adv. Healthc. Mater. 2016, 5 (24), 3157–3164. [3] Liang, Y.; Kiick, K. L. Heparin-Functionalized Polymeric Biomaterials in Tissue Engineering and Drug Delivery Applications. Acta Biomater. 2014, 10 (4), 1588–1600. [4] Blossom, D. B.; Kallen, A. J.; Patel, P. R.; Elward, A.; Robinson, L.; Gao, G. et al. Outbreak of Adverse Reactions Associated with Contaminated Heparin. N. Engl. J. Med. 2008, 359 (25), 2674–2684. [5] Hirsh, J.; Dalen, J. E.; Anderson, D. R.; Poller, L.; Bussey, H.; Ansell, J. et al. Oral Anticoagulants. Chest 1998, 114 (5), 445S-469S.

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Myelodysplastic neoplasms (MDS) are a group of heterogeneous, clonal disorders characterised by ineffective haematopoiesis and peripheral blood cytopenia. MDS is highly progressive, difficult to treat, and is one of the most common blood cancers, affecting 4-5/100.000 people below the age of 70 and many more thereafter. Single or multiple driver gene mutations and chromosomal abnormalities in the haematopoietic compartment lead to MDS. These somatic gene mutations account for the dysregulation of epigenetic, DNA repair, cohesion complex, and spliceosome pathways. The International prognostic scoring system (IPSS) that was developed in 1997, revised (IPSS-R) in 2016 and updated in 2022 (IPSS-M) classifies MDS into low risk (LR-), intermediate (Int-), and high risk (HR-) groups. The haematopoietic disorder is accompanied by changes in the bone marrow microenvironment (BMME) and especially in mesenchymal cells (MSCs). BMME provides a supportive milieu for haematopoiesis and can be targeted by clinically available drugs such as AZA. The non cellular component of the BMME, the extracellular matrix (ECM), is a framework providing structural and biochemical support via cell-ECM interactions and the maintenance of growth factor gradients. To date, studies of bone marrow interactions in homeostasis and disease have focused largely on soluble and membrane-associated factors, while the involvement of the ECM in MDS and its response to therapy is underexplored. Therefore, this study aimed to characterise the MDS MSC derived ECM of both LR- and HR-MDS in comparison to that from healthy age matched donors in terms of composition, biophysical properties and functional haematopoietic support. This study also aimed to evaluate the impact of in vivo and in vitro AZA treatment on MDS MSC derived ECM. To investigate this, in vitro ECMs were generated by culturing of MSC monolayers on chemically prepared coverslips followed by decellularization using NH4OH and DNase-1 solution. The biophysical properties of the ECM were analysed using atomic force microscopy (AFM). Using targeted approaches, a selection of biochemical ECM components including glycoprotein (fibronectin), collagens and glycosaminoglycans (GAGs) were analysed in the various ECMs generated from the different MSC samples. AFM analysis revealed that MDS MSCs producer a softer ECM than the healthy donor MSCs, and that this difference becomes more prominent as the disorder progresses from LR-to HR- MDS. An increase in overall collagen content and a specific increase in collagens I and IV was observed in the ECM deposited by both LR- and HR-MDS MSCs when compared to healthy donor MSCs. Lectin staining revealed disease stage-specific differences in GAG composition: The levels of GAGs carrying N acetyl glucosamine and those carrying N-acetyl galactosamine sugars were both increased in ECM from LR-MDS, while ECM from HR-MDS retained high levels of N acetyl glucosamine but contained only low levels of N-acetyl galactosamine GAGs. The changes in N acetyl galactosamine and N acetyl glucosamine GAGs were further confirmed by chondroitin sulphate (CS) immunostaining, and hyaluronic acid (HA) ELISA respectively. Electrophoretic analysis revealed the presence of low molecular weight (LMW)-HA in one of the LR-MDS MSC derived ECM. Furthermore, the stimulation of MNCs with LMW-HA showed an increase in gene expression of pro-inflammatory cytokines like IL6 suggesting the possible involvement of LMW-HA in the inflammatory bone marrow state of LR-MDS. ECM derived from both LR- and HR-MDS MSCs had a reduced ability to support HSPC, as revealed by a loss of both polar morphology and subsequent colony-forming potential. The decreased rigidity of the ECM produced by MSCs from MDS patients was reversed in MSCs isolated from the patients post-AZA therapy. Similarly, direct exposure of cultured MDS MSCs to AZA also resulted in a corresponding increase in the rigidity of the ECM, although this remained lower than that observed from MDS MSCs isolated post-AZA therapy. A reduction in the collagen content of the ECM was only observed when using MSC from AZA-treated patients, but not following in vitro AZA treatment of MSCs from untreated patients. This indicated that the AZA-mediated restoration of ECM rigidity is an indirect result of effects in the context of the BMME and not on the MSCs alone. Interestingly, a few ECMs derived from MDS patients after AZA therapy had an improved ability to maintain functional HSPCs, as assessed by subsequent colony formation assay. Moreover, a polarized morphology of HSPCs cultured on the ECM derived from both in vivo and in vitro AZA-treated MDS MSCs, suggests a partial restoration of the HSPC behaviour on the AZA-treated MDS ECM. In conclusion, this study has demonstrated changes in the structure, collagen content, and GAG composition of ECM derived from MSCs from MDS patients compared to healthy donors. This study is one of the first to demonstrate an impact of MDS-derived ECM on both the morphology and function of HSPCs, supporting the relevance of the bone marrow ECM in haematological malignancies. The partial revision of the MDS ECM phenotype following in vivo AZA treatment suggests that the ECM itself may be a potential therapeutic target. An improved, in-depth understanding of the contribution of ECM to disease processes is therefore likely to enable us to find novel therapeutic targets to improve drug response in MDS in the future. / Myelodysplastische Neoplasien (MDS) sind eine Gruppe heterogener, klonaler Erkrankungen, die durch ineffektive Hämatopoese und Zytopenie des peripheren Blutes gekennzeichnet sind. MDS sind hochgradig progressiv, schwer zu behandeln und gehören zu den häufigsten Blutkrebserkrankungen, von denen 4-5/100.000 Menschen unter 70 Jahren betroffen sind. Die Inzidenz steigt mit zunehmendem Alter deutlich an. MDS wird durch einzelne oder mehrfache Mutationen von Treibergenen und Chromosomenanomalien im hämatopoetischen Kompartiment verursacht. Diese somatischen Genmutationen sind für die Dysregulation von epigenetischen, DNA-Reparatur-, Kohäsionskomplex- und Spleißosomen-Signalwegen verantwortlich. Das Internationale Prognosesystem (IPSS) wurde 1997 entwickelt, 2016 überarbeitet (IPSS-R) und 2022 aktualisiert (IPSS M), um MDS in Gruppen mit niedrigem Risiko (LR-), mittlerem (Int ) und hohem Risiko (HR-) einzuteilen. Die hämatopoetische Erkrankung geht mit Veränderungen in der Mikroumgebung des Knochenmarks (BMME) einher, insbesondere bei mesenchymalen Zellen (MSCs). Das BMME bietet ein unterstützendes Milieu für die Hämatopoese und kann durch klinisch verfügbare Medikamente wie AZA beeinflusst werden. Die nichtzelluläre Komponente der BMME, die extrazelluläre Matrix (ECM), ist ein Gerüst, das durch Zell-ECM-Interaktionen und die Aufrechterhaltung von Wachstumsfaktorgradienten strukturelle und biochemische Unterstützung bietet. Bislang haben sich Studien über die Interaktionen im Knochenmark bei Homöostase und Krankheit hauptsächlich auf lösliche und membranassoziierte Faktoren konzentriert, während die Beteiligung der ECM an MDS und ihre Reaktion auf die Therapie noch nicht ausreichend erforscht ist. Daher zielte diese Studie darauf ab, die aus MDS-MSCs abgeleitete ECM sowohl bei LR- als auch bei HR-MDS im Vergleich zu der von gesunden, altersgleichen Spendern zu charakterisieren, und zwar hinsichtlich der Zusammensetzung, der biophysikalischen Eigenschaften und der funktionellen hämatopoetischen Unterstützung. Ziel dieser Studie war es auch, die Auswirkungen einer in vivo und in vitro AZA-Therapie auf die aus MDS-MSCs stammende ECM zu untersuchen. Hierfür wurden in vitro ECMs durch Kultivierung von MSC-Monolayern auf chemisch-präparierten-Deckgläsern und anschließender Dezellularisierung mit NH4OH und DNase-1-Lösung erzeugt. Die biophysikalischen Eigenschaften der ECM wurden mittels Rasterkraftmikroskopie (AFM) analysiert. Mit gezielten Ansätzen wurde eine Auswahl biochemischer ECM-Komponenten, darunter Glykoproteine (Fibronektin), Kollagene und Glykosaminoglykane (GAGs), in den ECMs analysiert. Die AFM-Analyse ergab eine weichere ECM, die von MDS-MSCs im Vergleich zu gesunden Spender-MSCs gebildet wurde, was mit dem Fortschreiten der Erkrankung von LR- zu HR-MDS noch deutlicher wurde. Sowohl in LR-MDS- als auch in HR-MDS-ECMs wurde im Vergleich zu gesunden Spender-ECMs ein Anstieg des Gesamtkollagengehalts und eine spezifische Zunahme der Kollagene I und IV beobachtet. Darüber hinaus zeigte die Lektinfärbung krankheitsspezifische Unterschiede in der GAG-Zusammensetzung: Der Gehalt an N-Acetylglucosamin-tragenden GAGs und an N-Acetylgalactosamin-tragenden GAGs war in der ECM von LR-MDS erhöht, während die ECM von HR-MDS einen hohen Gehalt an N-Acetylglucosamin, aber nur einen geringen Gehalt an N-Acetylgalactosamin-GAGs aufwies. Die Veränderungen bei den N-Acetyl-Galactosamin- und N-Acetyl-Glucosamin-GAGs wurden durch Chondroitinsulfat (CS)-Immunfärbung bzw. Hyaluronsäure (HA) ELISA weiter bestätigt. Eine Elektrophoretische Analyse zeigte das Vorhandensein von niedermolekularem (LMW)-HA in einer der von LR-MDS-MSCs stammenden ECM. Darüber hinaus zeigte die Stimulierung von mononuklearen Zellen mit LMW-HA einen Anstieg der Genexpression von pro-inflammatorischen Zytokinen wie IL6, was auf eine Rolle von LMW-HA im entzündlichen Zustand des Knochenmarks von LR-MDS hindeutet. Darüber hinaus wies die ECM von LR- und von HR-MDS, eine verminderte Fähigkeit, hämatopoetische Stammvorläuferzellen (HSPCs) zu unterstützen, auf. Dies zeigte sich in einem Verlust sowohl der polaren Morphologie von HSPCs als auch des anschließenden koloniebildenden Potenzials selbiger. Darüber hinaus wurde die verringerte Steifigkeit der ECM von MDS-MSCs, die nach der AZA-Therapie aus den Patienten isoliert wurden, umgekehrt. In ähnlicher Weise führte die direkte Exposition von kultivierten MDS-MSCs mit AZA zu einer entsprechenden Erhöhung der Steifigkeit der ECM. Diese war jedoch geringer als bei den nach der AZA-Therapie isolierten MDS-MSCs. Die Verringerung des Kollagengehalts der ECM wurde nur in der in vivo mit AZA behandelten MSC-ECM beobachtet, nicht aber in den in vitro mit AZA behandelten Proben. Dies deutet darauf hin, dass die AZA-vermittelte Wiederherstellung der ECM-Steifigkeit ein Ergebnis der indirekten Wirkung von AZA im Knochenmark ist und eventuell vom MDS-Klon ausgeht. Interessanterweise wurde bei einigen ECMs von MDS-Patienten nach der AZA-Therapie eine Verbesserung der Koloniebildung hierauf- kultivierter HSPCs beobachtet. Darüber hinaus deutet eine polarisierte Morphologie von HSPCs, die auf der ECM von in vivo und in vitro AZA-behandelten MDS-MSCs vorkultiviert wurden, auf eine teilweise Wiederherstellung des Verhaltens von HSPCs auf der AZA-behandelten MDS-ECM hin. Zusammenfassend lässt sich sagen, dass diese Studie Veränderungen in der Struktur, im Kollagengehalt und in der GAG-Zusammensetzung zwischen der ECM von MDS-MSCs und der ECM von gesunden MSCs nachgewiesen hat. Dies ist auch eine der ersten Studien, die einen Einfluss der aus MDS-MSCs stammenden ECM auf die Morphologie und Funktion von HSPCs zeigt. Dies weist auf die Rolle der ECM bei der Entstehung hämatologischer Malignome hin. Darüber hinaus deutet die teilweise Korrektur des MDS-ECM-Phänotyps nach einer in vivo AZA-Behandlung darauf hin, dass die ECM selbst ein potenzielles therapeutisches Ziel sein könnte. Ein besseres und tieferes Verständnis des Beitrags der ECM zu MDS-Krankheitsprozessen wird es uns daher ermöglichen, neue therapeutische Ziele zu finden, um das Ansprechen auf Medikamente verbessern zu können