This thesis describes the possible applicability of mesenchymal stromal cells (MSCs) in the treatment of liver fibrosis. In CCL4 induced animal models for liver fibrosis, we showed that local... Show moreThis thesis describes the possible applicability of mesenchymal stromal cells (MSCs) in the treatment of liver fibrosis. In CCL4 induced animal models for liver fibrosis, we showed that local administration of MSCs after partial hepatectomy, results in a dose‐dependent on‐site amelioration of fibrosis. Furthermore, we compared the pro-regenerative and anti-fibrotic effects of four different subpopulations of MSCs, categorized on Endoglin (CD105) and VCAM (CD106) membrane expression. Our results showed that VCAM-positive subpopulations of MSCs are superior compared to VCAM-negative subpopulations in relation to their anti-fibrotic and pro-regenerative properties. In another study we showed that TAA induce liver fibrogenesis in zebrafish embryos through mechanisms similar to man and mice. In addition, we found that MSCs ameliorate fibrogenesis in this model.CRIPTO-1 is an (onco)foetal protein and is correlated to poor prognosis in HCC. The observations of our HCC study are suggestive for the existence of a more aggressive subgroup of HCCs recognized by their high CRIPTO-1 expression which also seems to be resistant to Sorafenib treatment. Cell survival and cell proliferation are some of the processes stimulated by CRIPTO-1, which are also known to be important during liver regeneration and fibrogenesis. We identified that multiple species show enhanced CRIPTO-1 during fibrogenesis and that elevated CRIPTO-1 plasma levels in humans with cirrhosis normalize after liver transplantation. Show less
Tuberculosis (TB) is the most prevalent bacterial infectious disease in the world, caused by the pathogen Mycobacterium tuberculosis (Mtb). In this study, we have used Mycobacterium marinum (Mm)... Show moreTuberculosis (TB) is the most prevalent bacterial infectious disease in the world, caused by the pathogen Mycobacterium tuberculosis (Mtb). In this study, we have used Mycobacterium marinum (Mm) infection in zebrafish larvae as an animal model for this disease to study the role of the myeloid differentiation factor 88 (Myd88), the key adapter protein of Toll-like receptors. Previously, Myd88 has been shown to enhance innate immune responses against bacterial infections, and in the present study, we have investigated the effect of Myd88 deficiency on the granuloma morphology and the intracellular distribution of bacteria during Mm infection. Our results show that granulomas formed in the tail fin from myd88 mutant larvae have a more compact structure and contain a reduced number of leukocytes compared to the granulomas observed in wild-type larvae. These morphological differences were associated with an increased bacterial burden in the myd88 mutant. Electron microscopy analysis showed that the majority of Mm in the myd88 mutant are located extracellularly, whereas in the wild type, most bacteria were intracellular. In the myd88 mutant, intracellular bacteria were mainly present in compartments that were not electron-dense, suggesting that these compartments had not undergone fusion with a lysosome. In contrast, approximately half of the intracellular bacteria in wild-type larvae were found in electron-dense compartments. These observations in a zebrafish model for tuberculosis suggest a role for Myd88-dependent signalling in two important phenomena that limit mycobacterial growth in the infected tissue. It reduces the number of leukocytes at the site of infection and the acidification of bacteria-containing compartments inside these cells. Show less
Hoeksma, J.; Zon, G.C.M. van der; Dijke, P. ten; Hertog, J. den 2020
Zebrafish models are well-established tools for investigating the underlying mechanisms of diseases. Here, we identified cercosporamide, a metabolite from the fungus Ascochyta aquiliqiae, as a... Show moreZebrafish models are well-established tools for investigating the underlying mechanisms of diseases. Here, we identified cercosporamide, a metabolite from the fungus Ascochyta aquiliqiae, as a potent bone morphogenetic protein receptor (BMPR) type I kinase inhibitor through a zebrafish embryo phenotypic screen. The developmental defects in zebrafish, including lack of the ventral fin, induced by cercosporamide were strikingly similar to the phenotypes caused by renowned small-molecule BMPR type I kinase inhibitors and inactivating mutations in zebrafish BMPRs. In mammalian cell-based assays, cercosporamide blocked BMP/SMAD-dependent transcriptional reporter activity and BMP-induced SMAD1/5-phosphorylation. Biochemical assays with a panel of purified recombinant kinases demonstrated that cercosporamide directly inhibited kinase activity of type I BMPRs [also called activin receptor-like kinases (ALKs)]. In mammalian cells, cercosporamide selectively inhibited constitutively active BMPR type I-induced SMAD1/5 phosphorylation. Importantly, cercosporamide rescued the developmental defects caused by constitutively active Alk2 in zebrafish embryos. We believe that cercosporamide could be the first of a new class of molecules with potential to be developed further for clinical use against diseases that are causally linked to overactivation of BMPR signaling, including fibrodysplasia ossificans progressiva and diffuse intrinsic pontine glioma.This article has an associated First Person interview with the first author of the paper. Show less
This thesis elucidated the possibility of manipulating BMP/TGFβ signaling to achieve inhibition of breast cancer metastasis, including boosting BMP signaling via blockade of the BMP antagonist... Show moreThis thesis elucidated the possibility of manipulating BMP/TGFβ signaling to achieve inhibition of breast cancer metastasis, including boosting BMP signaling via blockade of the BMP antagonist Grem1 extracellularly or via stimulation of small-molecule compounds intracellularly, preventing TGFβ signaling to allow accumulation of pro-oncogenic stimuli. We also highlight the importance of selecting appropriate cancer types when adopting dual inhibition of PD-L1 and TGFβ signaling. I hope my research will aid in more efficient clinical cancer therapies. Show less
Ren, J.; Smid, M.; Iaria, J.; Salvatori, D.C.F.; Dam, H. van; Zhu, H.J.; ... ; Dijke, P. ten 2019
The aim of this study was to investigate the hepatotoxic effect and its underlying mechanism of aloe emodin (AE). AE was docked with the targets of NF-kappa B inflammatory pathway and P53 apoptosis... Show moreThe aim of this study was to investigate the hepatotoxic effect and its underlying mechanism of aloe emodin (AE). AE was docked with the targets of NF-kappa B inflammatory pathway and P53 apoptosis pathway respectively by using molecular docking technique. To verify the results of molecular docking and further investigate the hepatotoxicity mechanism of AE, the zebrafish Tg (fabp10: EGFP) was used as an animal model in vivo. The pathological sections of zebrafish liver were analyzed to observe the histopathological changes and Sudan black B was used to study whether there were inflammatory reactions in zebrafish liver or not. Then TdT-mediated dUTP Nick-End Labeling (TUNEL) was used to detect the apoptotic signal of zebrafish liver cells, finally the mRNA expression levels as well as the protein expression levels of the targets in NF-kappa B and P53 pathways in zebrafish were measured by quantitative Real-Time PCR (qRT-PCR) and western blot. Molecular docking results showed that AE could successfully dock with all the targets of NF-kappa B and P53 pathways, and the docking scores of most of the targets were equal to or higher than that of the corresponding ligands. Pathological sections showed AE could cause zebrafish liver lesions and the result of Sudan black B staining revealed that AE blackened the liver of zebrafish with Sudan black B. Then TUNEL assay showed that a large number of dense apoptotic signals were observed in AE group, mainly distributed in the liver and yolk sac of zebrafish. The results of qRT-PCR and western blot showed that AE increased the mRNA and protein expression levels of pro-inflammatory and pro-apoptotic targets in NF-kappa B and P53 pathways. AE could activate the NF-kappa B inflammatory pathway and the P53 apoptosis pathway, and its hepatotoxic mechanism was related to activation of NF-.B-P53 inflammation-apoptosis pathways. Show less
