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The endometrium undergoes recurrent cycles of dynamic remodelling, involving breakdown and scarless repair, proliferation and differentiation, including decidualisation of the stroma, during the menstrual cycle. Extensive studies have characterised how the steroid hormones oestrogen and progesterone acting via their nuclear receptors coordinate these remarkable changes. Although a few previous studies have postulated a role for androgens the impact of androgens on endometrial function remains understudied. The studies described in this thesis aimed to 1) identify cellular processes, pathways and networks regulated by androgens in human androgen receptor-positive endometrial stromal cells (hESCs), 2) investigate the potential for regulation and determine the regulation of putative dihydrotestosterone (DHT)-regulated gene expression by androgen in hESCs, 3) investigate the expression and regulation of putative androgen-regulated genes in the human endometrium across the menstrual cycle and in early pregnancy and 4) explore the role of androgens in modulating metformin-induced gene expression associated with decidualisation of hESCs. Analysis of data from a whole genome array conducted previously in the laboratory using primary hESCs treated with DHT for 2 or 8 hours identified time dependant putative androgen-regulated mRNAs (34 and 268 genes, respectively). Thereafter, all work was completed by the author. Gene ontology and functional based bioinformatic analyses of the putative androgen-regulated gene sets revealed potential androgen regulation of a variety of cell processes, pathways and networks including those associated with gene transcription, signal transduction pathways (such as phosphatidylinositol, oestrogen receptor alpha (ERα) and Wnt signalling), cancer pathways, metabolism, cell cycle, development, apoptosis/survival. In addition, various transcription factors (e.g. AR, c-Myc, SP1, ERα, p53, E2F1, RUNX2, CREB1 and STAT3) were associated with androgen regulation in hESCs. Consensus androgen receptor binding sites were identified in the promoter sequences of 18 genes by transcription factor binding site sequence analysis. Direct DHT regulation of ten of 15 of these genes was validated in endometrial stromal cells using qRTPCR. Of these genes, RGS2, SIK1, and SNCAIP mRNAs were confirmed as DHT-regulated in hESCs by use of an AR inhibitor (flutamide) and in addition, were not found to be regulated by oestradiol. Discovery bioinformatics predicted these genes may interact in a gene network involving AR and the cAMP transduction pathway. Expression of the 15 putative androgen-regulated genes was confirmed by qRTPCR in intact human endometrial tissue (13 novel) and 9 of these genes were regulated in association with decidualisation i.e. either in the secretory phase, the time at which decidualisation begins and/or in first trimester decidua. Protein expression of RGS2, SIK1 and Synphilin-1 (encoded by SNCAIP) was confirmed by immunohistochemistry in endometrial tissues and protein expression also appeared greater in decidua. Regulation of putative androgen-regulated gene expression by decidualisation was confirmed in 4 out of 8 genes by employing a model of reduced in vivo decidualisation i.e. decidua from ectopic pregnancies. Regulation of 5 out of 7 genes was confirmed in decidualised hESCs (RGS2, SIK1, SLC6A6, SNCAIP and AXIN2) but expression of these genes was not altered by DHT inclusion during decidualisation. Finally, only a high metformin concentration enhanced hESC decidualisation and putative androgen-regulated gene expression (4 genes) in decidualised hESCs. In comparison, in the presence of DHT, a lower clinically relevant metformin concentration (100μM) did enhance decidualisation marker expression but did not alter expression of putative androgen-regulated genes. In summary, these studies have revealed new insights into androgen action in the human endometrium. Studies in hESCs 1) predicted the pathways and interacting transcription factor regulatory networks that may be androgen-dependent in this cell type, these were associated with cell differentiation, apoptosis and proliferation, 2) identified novel putative androgen-regulated genes expressed in hESCs and in endometrial tissues, 3) showed putative androgen-regulated genes are regulated by DHT (possibly via AR) in endometrial stromal cells, some of which are also regulated in association with decidualisation and 4) showed that androgens may enhance decidualisation during exposure to the commonly used drug metformin. Collectively, these new findings support a physiological role for androgens in endometrial function and provide a series of new avenues for further studies of the regulation of differentiation and proliferation.

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Orientador: Rogério Martins Amorim / Coorientador: Ana Liz Garcia Alves / Banca: Rui Seabra Ferreira Junior / Banca: Fernanda da Cruz Landim / Resumo: Estudos demonstram o grande potencial do uso das células estromais mesenquimais multipotentes (MSCs) como terapia celular. Seu uso em lesões neurológicas, que usualmente apresentam difícil regeneração, tem sido estudado pelo fato das MSCs apresentarem baixa imunogenicidade efeitos imunomoduladores e neuroregenerativos. Nesse contexto, o presente estudo avaliou a viabilidade e a segurança do transplante de MSCs alogênicas provenientes do tecido adiposo, medula óssea e cordão umbilical de equinos, pela via intratecal através do espaço intervertebral C1-C2, por meio de exame neurológico seriado, análises hematológicas e determinação dos níveis séricos de proteínas de fase aguda. Foram utilizados 16 equinos saudáveis, divididos em quatro grupos: grupo SHAM (SHAM) que recebeu o transplante de salina tamponada com fosfato (PBS); grupo tecido adiposo (GTA), recebeu MSCs de origem do tecido adiposo; grupo medula óssea (GMO), recebeu MSCs de origem da medula óssea; e grupo cordão umbilical (GCU), recebeu células de origem da matriz do cordão umbilical. Foram realizadas três aplicações com intervalo de 30 dias em cada grupo, e coletou-se amostras de sangue, nos momentos que antecederam os transplantes, M0, M30 e M60 e 24 horas, após o transplante, M1, M31, M61. E por último foi realizada uma coleta 30 dias após M60, caracterizando M90. Não foram observadas alterações do exame clinico, hematológico e nas proteínas de fase aguda relacionadas aos sucessivos transplantes intratecais de MSC... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Studies demonstrate the great potential of using multipotent mesenchymal stromal cells (MSCs) as cell therapy. Its use in neurological lesions, which usually present difficult regeneration, has been studied because MSCs have low immunogenicity and immunoregulatory and neuroregenerative effects. In this context, the present study evaluated the viability and safety of transplantation of allogeneic MSCs from the adipose tissue, bone marrow and umbilical cord of horses, through the intrathecal route through the C1-C2 intervertebral space, through serial neurological examination, hematological analyzes and determination of serum levels of acute phase proteins. Sixteen healthy horses were used, divided into four groups: SHAM group (SHAM) that received phosphate buffered saline (PBS) transplantation; adipose tissue group (GTA), received adipose tissue MSCs; bone marrow group (GMO), received MSCs from bone marrow origin; and umbilical cord (UGC) group, received cells from the umbilical cord array. M0, M30 and M60 were collected at the time of the transplantation, M1, M31 and M61 and 24 hours after transplantation. And finally a collection was performed 30 days after M60, characterizing M90. There were no changes in the clinical, hematological and acute phase-related proteins related to successive intrathecal transplantations of MSCs, nor were there alterations that contra indicated the use of any of the cellular sources, demonstrating that the protocol used, as well as any of cellula... (Complete abstract click electronic access below) / Mestre

Introduction. Safe closure of gastric luminal defects remains a big challenge for development of gastric endoscopic surgery. The aims of this thesis are to assess the effect and efficiency of Eagle Claw VIII (endoscopic suturing device)and adipose tissue-derived mesenchymal stem cells (ADMSCs) for closure and enhancing healing of gastric luminal defects. / Methods and Results. 1. Endoscopic suturing is superior to endoclips for closure of gastrotomy after NOTES. A 2cm linear incision on the body of porcine stomach was closed by hand suturing, Eagle Claw VIII or endoclips, respectively (n=17 for each group). The results indicated that all gastrotomies were successfully closed. Closure time was significantly longer in Eagle Claw VIII group. Bursting pressure of gastrotomies for Eagle Claw VIII was significantly higher than endoclips, but lower than hand suturing. Besides, both Eagle Claw VIII and endoclip closure encountered significantly technical challenges. This study suggested that Eagle Claw VIII had potential for endoscopic closure of gastrotomies, but need further refinement. / 2. ADMSCs for Acceleration of Healing of Sutured Gastric Perforation(SGP). ADMSCs were isolated and expanded in vitro, and characterized by stromal differentiations and cell surface markers. A 2cm SGP was produced on gastric body of rats. 5×10⁶ ADMSCs were transplanted into SGP by local injection (LI-ADMSCs) or topical spraying (TS-ADMSCs). Healing of SGP was assessed. LI-ADMCs significantly decreased peritoneal adhesion and wound dehiscence, and increased bursting pressure of SGP, when comparing to other experimental groups. Histologic analysis indicated that SGPs in LI-ADMSCs group had more re-epithelialization and collagen regeneration, and less inflammation. Expression of TGF-β1 was up-regulated, while IL-6 was down-regulated in LI-ADMSCs group, when comparing to fibrin and control groups. This study suggested that local injection of ADMSCs is an effective approach for accelerating the healing of SGP. / 3. Promoting Effect of ADMSCs on Healing of Gastric Ulcer is abrogated by NSAIDs. Gastric ulcer model in rats was successfully produced by using 70% acetic acid. A total of 1×10⁷ ADMSCs was locally injected into ulcer lesion. Ulcer area was measured at different time points. Therapeutic potentialof ADMSCs was assessed when NSAIDs was simultaneously administrated. The results demonstrated that ADMSCs significantly decreased ulcer area. Histologic assessment indicated that ADMSCs increased re-epithelialization, angiogenesis and collagen deposition, and suppressed inflammation. Transplanted ADMSCs homed into gastric ulcer lesion and differentiated into endothelial and smooth muscle cells. In addition, ADMSCs treatment increased the gene expressions for wound healing, and activated COX-2-PGE₂ and Erk1/2-MAPK signaling pathways. Repeated administration of Indomethacin reduced cell proliferation and angiogenesis, and eliminated ADMSCs-induced ulcer healing on day 10. The results suggested that ADMSCs promoted the healing of peptic ulcer, which is eliminated by NSAIDs. / Conclusions. Endoscopic suturing by Eagle Claw VIII is feasible for closure of gastrotomy, when comparing to endoclips. ADMSC promotes the healing of gastric luminal defects including SGP and ulcer. The promoting effect of ADMSC is PGE₂-dependent, and attenuated by NSAIDs. These evidences implied that combined use of endoscopic suturing and ADMSCs is a helpful approach for safe closure of gastrotomy and gastric perforation. / 引言：胃傷口癒合是胃消化內鏡手術發展的障礙之壹。本課題之目的是評價和探索Eagle Claw VIII和脂肪幹細胞(ADMSCs)縫合和促進胃內傷口癒合的效果和作用。 / 方法和結果：1. 內鏡縫合器Eagle Claw VIII閉合經胃自然腔道手術後傷口的效果評價體外豬胃體上造2cm的胃傷口模型，使用手工縫合、內鏡下Eagle Claw VIII縫合或內鏡夾閉合胃傷口；每組17個樣本。本研究提示所有胃傷口均成功閉合。Eagle Claw VIII縫合胃傷口時間顯著長於其他兩組的閉合時間。Eagle Claw VIII縫合的胃傷口破裂壓顯著高於內鏡夾閉組，但是明顯低於手工縫合組。此外，內鏡縫合和夾閉都面臨較大的技術難度。本研究提示Eagle Claw VIII有臨床運用的潛在價值，但需要進壹步改進。 / 2. 局部移植脂肪幹細胞促進胃穿孔癒合的實驗性研究：建立大鼠2cm胃體穿孔模型，局部註射或傷口表面塗抹法移植ADMSCs，觀察胃傷口癒合情況。局部註射移植ADMSCs顯著減輕胃傷口粘連和裂開發生率，增加胃傷口破裂壓。組織學分析提示ADMSCs治療促進傷口上皮和肉芽組織再生，抑制炎癥反應。此外，局部註射ADMSCs增加TGF-β1抑制IL-6表達。本研究提示局部註射移植ADMSCs是促進胃穿孔傷口癒合的有效方法。 / 3. 局部移植脂肪幹細胞促進胃饋瘍癒合的實驗性研究：使用70%醋酸建立大鼠胃體饋瘍模型；饋瘍病竈內局部註射移植1×107 ADMSCs。研究提示第10和15天ADMSCs顯著減小饋瘍面積。組織學研究提示ADMSCs增加饋瘍傷口上皮和血管再生，促進膠原蛋白分泌和抑制炎癥反應。移植的ADMSCs能夠在饋瘍病竈內成活，並分化成血管內皮細胞和平滑肌細胞。ADMSCs顯著提高促傷口癒合相關基因表達水準。此外，ADMSCs啟動COX-2-PGE2和Erk1/2-MAPK信號通路。第10天，和對照組相比，引哚美辛/ADMSCs組潰瘍病竈內細胞增殖和血管再生顯著降低、饋瘍癒合延遲。本研究提示脂ADMSCs促進胃饋瘍癒合；非甾體抗炎藥顯著減弱ADMSCs的促胃饋瘍癒合作用。 / 結論：與內鏡夾閉相比，Eagle Claw VIII內鏡縫合胃創口有可行性。ADMSCs促進胃穿孔和饋瘍癒合，且依賴於前列腺素E2；引哚美辛抑制前列腺素E2合成從而抑制ADMSCs促胃組織癒合之效能。本研究提示聯合使用內鏡縫合器和ADMSCs是促進胃傷口癒合的潛在有效方法。 / Thesis Ph.D. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 152-162). / Abstracts also in Chinese. / Title from PDF title page (viewed on 11, October, 2016). / Liu, Liu. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

Bone tissue engineering strategies are currently being developed as alternative mechanisms to address the clinical demand for bioactive and biomechanical graft material. To date, these efforts have been largely restricted by inadequate supply of committed osteoprogenitor cells and loss of osteoblastic phenotype expression following in vitro culture and expansion. The objective of this thesis research was to address the cell sourcing limitations of tissue-engineered bone grafts through constitutive and sustained overexpression of the osteoblast-specific transcriptional activator Runx2/Cbfa1 in osteogenic marrow-derived stromal cells using retroviral gene delivery. Runx2 overexpression enhanced expression of multiple osteoblastic genes proteins and, more importantly, significantly up-regulated matrix mineralization in both monolayer culture and following cell seeding in 3-D polymeric scaffolds. To evaluate in vivo performance, Runx2-expressing cells were seeded into 3-D constructs and implanted both subcutaneously and in a critical size craniotomy bone defect model. Notably, in vitro pre-culture of Runx2-transduced cell-seeded constructs prior to implantation significantly enhanced their capacity to form mineralized tissue in the subcutaneous space and induce new bone formation in the critical size defect model compared to control cells. The described series of analyses provided a novel combination of tissue and genetic engineering techniques toward the development of a Runx2-modified stromal cell/polymeric scaffold composite tissue-engineered bone graft substitute.

Modular tissue engineering involves assembling tissue constructs with integral vasculature from units containing adipose-derived mesenchymal stromal cells (adMSCs) and endothelial cells. Here, the effects of implant volume and adMSC density on the vascularization of modular tissues were explored. Both parameters affected the contributions of host- and graft-derived vessels, without affecting total vessel density. Increasing implant volume from 0.01 to 0.10 mL increased HIF1α expression and graft-derived vessel density, suggesting a role of hypoxia in graft-derived vessel formation. However, increasing adMSC density within small-volume implants did not increase HIF1α expression. Vascularization of small-volume implants of high (4.3•10^6 cells/mL) and low (1.0•10^6 cells/mL) adMSC densities was dominated by host vessel ingrowth at day 7. By increasing adMSC density, a high proportion of host-derived vessels was maintained to day 14, presumably via paracrine effects. Further dissection of the role of hypoxia in modular tissue engineering remains a promising avenue to pursue.

Modular tissue engineering involves assembling tissue constructs with integral vasculature from units containing adipose-derived mesenchymal stromal cells (adMSCs) and endothelial cells. Here, the effects of implant volume and adMSC density on the vascularization of modular tissues were explored. Both parameters affected the contributions of host- and graft-derived vessels, without affecting total vessel density. Increasing implant volume from 0.01 to 0.10 mL increased HIF1α expression and graft-derived vessel density, suggesting a role of hypoxia in graft-derived vessel formation. However, increasing adMSC density within small-volume implants did not increase HIF1α expression. Vascularization of small-volume implants of high (4.3•10^6 cells/mL) and low (1.0•10^6 cells/mL) adMSC densities was dominated by host vessel ingrowth at day 7. By increasing adMSC density, a high proportion of host-derived vessels was maintained to day 14, presumably via paracrine effects. Further dissection of the role of hypoxia in modular tissue engineering remains a promising avenue to pursue.

Acute myeloid leukemia (AML) often remains refractory to current chemotherapy and transplantation approaches despite many advances in our understanding of mechanisms in leukemogenesis. The bone marrow “niche” or microenvironment, however, may be permissive to leukemia development and studying interactions between the microenvironment and leukemia cells may provide new insight for therapeutic advances. Mesenchymal stem cells (MSCs) are central to the development and maintenance of the bone marrow niche and have been shown to have important functional alterations derived from patients with different hematological disorders. The extent to which MSCs derived from AML patients are altered remains unclear. The aim of this study was to detect changes occurring in MSCs obtained from human bone marrow in patients with AML by comparing their function and gene expression pattern with normal age-matched controls. MSCs expanded from patients diagnosed with acute leukemia were observed to have heterogeneous morphological characteristics compared to the healthy controls. Immunohistochemistry and flow data confirmed the typical cell surface immunophenotype of CD90+ CD105+ CD73+ CD34- CD45-, although MSCs from two patients with AML revealed reduced surface expression of CD105 and CD90 antigens respectively. Differentiation assays demonstrated the potential of MSCs from AML patients and healthy donors to differentiate into bone, fat and cartilage. However, the ability of MSCs from AML samples to support hematopoietic function of CD34+ progenitors was found to be impaired while the key hematopoietic genes were found to be differentially expressed on AML-MSCs compared to nMSCs. These studies indicate that there exist differences in the biologic profile of MSCs from AML patients compared to MSCs derived from healthy donors. The results described in the thesis provide a formulation for additional studies that may allow us to identify new targets for improved treatment of AML.