Background Paediatric Huntington disease with highly expanded mutations (HE-PHD; >80 CAG repeats) presents atypically, compared to adult-onset Huntington disease (AOHD), with neurodevelopmental... Show moreBackground Paediatric Huntington disease with highly expanded mutations (HE-PHD; >80 CAG repeats) presents atypically, compared to adult-onset Huntington disease (AOHD), with neurodevelopmental delay, epilepsy, abnormal brain glucose metabolism, early striatal damage, and reduced lifespan. Since genetic GLUT-1 deficiency syndrome shows a symptom spectrum similar to HE-PHD, we investigated the potential role of the two main glucose transporters, GLUT-1 and GLUT-3, in HE-PHD.Methods We compared GLUT-1 and GLUT-3 protein expression in HE-PHD, juvenile-onset (JOHD), and AOHD brains (n = 2; n = 3; n = 6) and periphery (n = 3; n = 2; n = 2) versus healthy adult controls (n = 6; n = 6). We also investigated mitochondrial complexes and hexokinase-II protein expression.Findings GLUT-1 and GLUT-3 expression were significantly lower in HE-PHD frontal cortex (p = 0.009, 95% [CI 13.4, 14.7]; p = 0.017, 95% [CI 14.2, 14.5]) versus controls. In fibroblasts, GLUT-1 and GLUT-3 expression were lower compared to controls (p < 0.0001, 95% [CI 0.91, 1.09]; p = 0.046, 95% [CI 0.93, 1.07]). In the frontal cortex, this occurred without evidence of extensive neuronal degeneration. Patients with HE-PHD had deregulated mitochondrial complex expression, particularly complexes II-III, levels of which were lower in frontal cortex versus controls (p = 0.027, 95% [CI 17.1, 17.6]; p = 0.002, 95% CI [16.6, 16.9]) and patients with AOHD (p = 0.052, 95% [CI 17.0, 17.6]; p = 0.002, 95% [CI 16.6, 16.7]). Hexokinase-II expression was also lower in HEPHD frontal cortex and striatum versus controls (p = 0.010, 95% [CI 17.8, 18.2]; p = 0.045, 95% [CI 18.6, 18.7]) and in frontal cortex versus patients with AOHD (p = 0.013, 95% [CI 17.7, 18.1]). Expression JOHD levels were consistently different to those of HE-PHD but similar to those of AOHD.Interpretation Our data suggest a dysfunctional hypometabolic state occurring specifically in paediatric Huntington disease brains. Show less
Mutations in Bone Morphogenetic Protein (BMP) Receptor (BMPR)1A and SMAD4 are detected in 50% of juvenile polyposis syndrome (JPS) patients, who develop stroma-rich hamartomatous polyps. The... Show moreMutations in Bone Morphogenetic Protein (BMP) Receptor (BMPR)1A and SMAD4 are detected in 50% of juvenile polyposis syndrome (JPS) patients, who develop stroma-rich hamartomatous polyps. The established role of stromal cells in regulating BMP activity in the intestine implies a role for stromal cells in polyp development. We used conditional Cre-LoxP mice to investigate how specific loss of BMPR1A in endothelial cells, fibroblasts, or myofibroblasts/smooth muscle cells affects intestinal homeostasis. Selective loss of BMPR1A in fibroblasts causes severe histological changes in the intestines with a significant increase in stromal cell content and epithelial cell hyperproliferation, leading to numerous serrated polyps. This phenotype suggests that crucial changes occur in the fibroblast secretome that influences polyp development. Analyses of publicly available RNA expression databases identified CXCL12 as a potential candidate. RNAscope in situ hybridization showed an evident increase of Cxcl12-expressing fibroblasts. In vitro, stimulation of fibroblasts with BMPs resulted in downregulation of CXCL12, while inhibition of the BMP pathway resulted in gradual upregulation of CXCL12 over time. Moreover, neutralization of CXCL12 in vivo in the fibroblast-specific BMPR1A KO mice resulted in a significant decrease in polyp formation. Finally, in CRC patient specimens, mRNA-expression data showed that patients with high GREMLIN1 and CXCL12 expression had a significantly poorer overall survival. Significantly higher GREMLIN1, NOGGIN, and CXCL12 expression were detected in the Consensus Molecular Subtype 4 (CMS4) colorectal cancers, which are thought to arise from serrated polyps. Taken together, these data imply that fibroblast-specific BMP signaling-CXCL12 interaction could have a role in the etiology of serrated polyp formation. Show less
The TME has increasingly been recognized as an important player in tumor progression and metastasis and a possible target for therapy. The TME consists of multiple cell types secreting growth... Show moreThe TME has increasingly been recognized as an important player in tumor progression and metastasis and a possible target for therapy. The TME consists of multiple cell types secreting growth factors and cytokines that exert either pro- or anti-tumor effects. This thesis mainly focuses on studies of the TME, especially the effects of Endoglin, on several cell types within the TME, including endothelial cells, fibroblasts, and immune cells.The TME has increasingly been recognized as an important player in tumor progression and metastasis and a possible target for therapy. The TME consists of multiple cell types secreting growth factors and cytokines that exert either pro- or anti-tumor effects. This thesis mainly focusses on studies of the TME, especially the effects of Endoglin, on several cell types within the TME, including endothelial cells, fibroblasts, and immune cells. This thesis aims to unravel the role of Endoglin as a possible target on various cell types within the TME of solid tumors. Endoglin is known for its role during angiogenesis, however, an increasing number of studies have shown the importance of Endoglin expression on several other cell types (e.g., immune cells, CAFs, tumor cells). Show less
For many years, cancer has been described as the accumulation of germinal and somatic mutations of the genome, impairing the function of tumor suppressor genes and stimulating oncogenes. Nowadays,... Show moreFor many years, cancer has been described as the accumulation of germinal and somatic mutations of the genome, impairing the function of tumor suppressor genes and stimulating oncogenes. Nowadays, it is commonly accepted that the tumor is not only a mass of malignant cells, rather than the result of a delicate network of interactions between tumor and stromal cells. Indeed, bidirectional communications between cancer cells and the surrounding microenvironment can strongly influence tumor development and progression. Stromal cells might support tumorigenesis, either via direct cell-cell contact mechanisms with tumor cells, or by releasing specific factors, including cytokines and growth factors in the surrounding extracellular matrix (ECM), with remodeling of the tumor microenvironment (TME) as a result.The aim of this thesis is to elucidate the delicate network of interactions between different TME components and tumor cells in prostate cancer (PCa) and oropharyngeal squamous cell carcinoma (OPSCC). Show less
This thesis describes the development of human skin equivalents that show characteristics of skin aging. The type of skin equivalent used was a fibroblast derived matrix equivalent, in which... Show moreThis thesis describes the development of human skin equivalents that show characteristics of skin aging. The type of skin equivalent used was a fibroblast derived matrix equivalent, in which the dermal compartment is generated by fibroblasts and thus is fully of human origin. Two strategies are described to include characteristics of skin aging in skin equivalents. Firstly, skin equivalents generated with senescent fibroblasts show some signs of skin aging, like increased MMP production and increased epidermal stress. However, some characteristics, like reduced epidermal turnover, are noticably lacking. The second strategy involved using papillary and reticular fibroblasts. During aging the papillary dermis shrinks in size, which leads to a relative increase of reticular fibroblasts over papillary fibroblasts. Equivalents generated with reticular fibroblasts showed reduced epidermal turnover and disturbed epidermal differentiation compared to equivalents generated with papillary fibroblasts. In addition, we showed that papillary fibroblasts can differentiate into reticular fibroblasts in vitro. This leads to the hypothesis that during skin aging papillary fibroblasts differentiate into reticular fibroblasts, leading to changes in both dermal and epidermal homeostasis. Further research with equivalents described in this thesis can further elucidate the role of papillary and reticular fibroblasts during skin aging. Show less
This thesis describes to which extent the skin reflects the aging process, with a specific focus on cellular senescence. Since the first descriptions of the growth arrested state of... Show more This thesis describes to which extent the skin reflects the aging process, with a specific focus on cellular senescence. Since the first descriptions of the growth arrested state of fibroblasts upon multiple replication rounds, cellular senescence has now emerged as a promising target to regulate the aging process in vivo as well. Here, we study whether fibroblast senescence in vitro is associated with in vivo donor characteristics such as chronological age and prevalence of disease. We further describe in this thesis whether senescence in skin tissue (in situ) is associated with other histological skin characteristics and with in vivo donor characteristics. Show less
Dendritic cells (DCs) are antigen-presenting cells (APCs) which play a key role in the regulation of immune responses. DCs are often referred to as __professional__ APCs, since their primary... Show moreDendritic cells (DCs) are antigen-presenting cells (APCs) which play a key role in the regulation of immune responses. DCs are often referred to as __professional__ APCs, since their primary function is to present antigens from pathogens or malignant cells. Consequently, there is a great deal of interest in how DCs might be exploited as a form of immunotherapy e.g. to induce immunity to cancers. However, DCs are also thought to play an important role in directing regulatory immune responses to innocuous antigens, which are targeted in autoimmune disease or during transplantation. Soluble factors secreted by DCs are crucial mediators in determining this balance between the immunogenic and regulatory arms of the immune system. One such group of factors is cytokines and one family which is gaining increasing attention is the IL-12 family. It is composed of four members; two are immunogenic and their expression has been very well characterised in DCs. The other two are regulatory, but relatively little is known about their regulation and expression in DC populations. In this thesis we aim to give a comprehensive overview of the expression and regulation of IL-12 family members in human DCs, with a particularly emphasis on IL-12, IL-27 and IL-35. Show less
Janson, D.; Rietveld, M.; Willemze, R.; Ghalbzouri, A. el 2013
To treat various cardiac diseases, modification of gene expression for the purpose of increased or decreased expression of a particular gene, is regarded as a potential therapy. As a vehicle to... Show moreTo treat various cardiac diseases, modification of gene expression for the purpose of increased or decreased expression of a particular gene, is regarded as a potential therapy. As a vehicle to introduce the gene of choice into the heart cell, virus vectors have given the most promising results. This thesis describes studies that are undertaken to investigate how virus vectors may be used to efficiently target cardiac cells and what the effects of certain genetic interventions are on the (patho)physiology of heart cells. We used lentivirus vectors to study the effects of integrin stimulation in neonatal rat cardiomyocytes on the uptake of macromolecules by these cells and through which pathway integrin stimulation leads to cardiac hypertrophy. Furthermore, the role of gap junctional coupling in the development of arrhythmias and in the cardiac differentiation of mesenchymal stem cells was investigated by modulating the expression of connexin 43 using lentivirus vectors. As adeno-associated virus vectors in particular have shown great potential as vector system to target the heart, we aimed to develop AAV vectors that may be used to specifically target either the cardiomyocytes or fibroblasts in the heart. Show less
Microtubuli (MT) zijn holle buisjes opgebouwd uit eiwit tubuline. Ze zijn meest bekend van hun rol in de celdeling, waarbij ze het genetisch materiaal verdelen over de twee dochtercellen. In een... Show moreMicrotubuli (MT) zijn holle buisjes opgebouwd uit eiwit tubuline. Ze zijn meest bekend van hun rol in de celdeling, waarbij ze het genetisch materiaal verdelen over de twee dochtercellen. In een niet delende cell vormen deze buisjes een netwerk door de cel heen en zijn betrokken bij verschillende processen, o.a. transport, cel polarisatie en celmigratie. Microtubuli groeien en krimpen aan hun uiteindes. Het meest dynamische uiteinde wordt ook het plus__eind genoemd. In dit onderzoek hebben we gekeken hoe deze plus__eindjes eruit zien als ze krimpen/ groeien. Zo hebben we mbv een electronen microscoop ingezoemd op de plus__eindjes van de microtubuli en deze in detail beschreven. We vonden negen verschillende vormen die plus__eindjes kunnen aannemen. Met behulp van een truuk hebben we uitgezocht welke vorm van de plus__eindjes behoort bij de krimpende of de groeiende en hoe de transitie van de groei naar de krimp verloopt. Onze resultaten hebben ook uitgewezen dat bepaalde plus__eindjes door de factoren in de cel vastgehouden kunnen worden. Dit betekent dat de structuur van de plus__eind belangrijk zou kunnen zijn voor de interacties met verschillende organellen. Kennis over deze interacties is van belang bij de begrijpen van de processen als celdeling, waarbij de plus__eindjes interactie met het genetisch materiaal aangaan. Show less
While currently available therapeutic options for the treatment of acute myocardial infarction are sufficient for the treatment of symptoms, the underlying causes usually remain unresolved, being... Show moreWhile currently available therapeutic options for the treatment of acute myocardial infarction are sufficient for the treatment of symptoms, the underlying causes usually remain unresolved, being loss of electrically active, contractile, myocardial tissue. Recently, extensive research has been performed in the field of cell and gene therapy. The ultimate aim of these therapies is to __heal__ the infarcted area on a more biological basis, by repopulating the damaged area with __new__ cells that contribute to proper cardiac function, including electrical activation of the myocardium. In order to comprehend the potential therapeutic value and hazard of cell modification and transplantation for ischemic heart diseases, one should consider the heart as a highly integrative, electromechanical organ. Therefore, the aim of this thesis was to explore, from a mechanistic and electrophysiological point of view, the integrative and functional aspects of cell modification and transplantation as therapeutic options to cure the damaged, ischemic heart. Show less
