Leo A van Grunsven

Vrije Universiteit Brussel | VUB · Liver Cell Biology Laboratory

Gain of 1q is a highly recurrent chromosomal abnormality in human pluripotent stem cells. In this work, we show that gains of 1q impact the differentiation capacity to derivates of the three germ layers, leading to mis-specification to cranial placode and non-neural ectoderm during neuroectoderm differentiation. Also, we found a weaker expression o...

Background and Aims Osteopontin (OPN) promotes the ductular reaction and is a major driver of chronic liver disease (CLD) progression. Although CLD is characterised by the accumulation of inflammatory cells including macrophages around the peri‐portal regions, the influence of OPN on recruitment is unclear. We investigated the role of OPN in cholan...

In this study, we show that undirected differentiation of human embryonic stem cells (hESC) to retinal pigment epithelium (RPE) acts as a selective barrier against aneuploid cells. Large-scale omics analysis reveals that 3–6% of cells of genetically normal hESC cultures are aneuploid, none of which progresses through RPE differentiation except for...

Objectives Hepatic CEACAM1 expression declines with advanced hepatic fibrosis stage in patients with metabolic dysfunction-associated steatohepatitis (MASH). Global and hepatocyte-specific deletions of Ceacam1 impair insulin clearance to cause hepatic insulin resistance and steatosis. They also cause hepatic inflammation and fibrosis, a condition c...

The lack of adequate human in vitro models that recapitulate the cellular composition and response of the human liver to injury hampers the development of anti-fibrotic drugs. The goal of this study was to develop a human spheroid culture model to study liver fibrosis by using induced pluripotent stem cell (iPSC)-derived liver cells. iPSCs were ind...

Objectives Hepatic CEACAM1 expression declines with advanced hepatic fibrosis stage in patients with MASH. Global and hepatocyte-specific deletions of Ceacam1 impair insulin clearance to cause hepatic insulin resistance and steatosis. They also cause hepatic inflammation and fibrosis, a condition characterized by excessive collagen production from...

Background & Aims Chronic liver disease (CLD) remains a global health issue associated with a significant disease burden. Liver fibrosis, a hallmark of CLD, is characterised by the activation of hepatic stellate cells (HSCs) that gain profibrotic characteristics including increased production of extracellular matrix protein. Currently, no antifibro...

Terminally differentiated cells are commonly regarded as the most stable cell state in adult organisms, characterized by growth arrest while fulfilling their specialized functions. A better understanding of the mechanisms involved in promoting cell cycle exit will improve the ability to differentiate pluripotent cells into mature tissues for both p...

Although human pluripotent stem cell (PSC)‐derived brain organoids have enabled researchers to gain insight into human brain development and disease, these organoids contain solely ectodermal cells and are not vascularized as occurs during brain development. Here it is created less complex and more homogenous large neural constructs starting from P...

Objective: Progressive hepatic fibrosis can be considered the final stage of chronic liver disease. Hepatic stellate cells (HSC) play a central role in liver fibrogenesis. Thyroid hormones (TH, e.g. thyroxine; T4 and triiodothyronine; T3) significantly affect development, growth, cell differentiation and metabolism through activation of TH recepto...

Gains of 1q are a highly recurrent chromosomal abnormality in human pluripotent stem cells. In this work, we show that gains of 1q impact the differentiation capacity to derivates of the three germ layers, leading to miss-specification to cranial placode and non-neural ectoderm during neuroectoderm differentiation and by poorer expression of lineag...

Gains of 1q are a highly recurrent chromosomal abnormality in human pluripotent stem cells. In this work, we show that gains of 1q impact the differentiation capacity to derivates of the three germ layers, leading to miss-specification to cranial placode and non-neural ectoderm during neuroectoderm differentiation and by poorer expression of lineag...

In vitro models of liver fibrosis have evolved from mono-cultures of primary rodent hepatic stellate cells and stellate cell lines, to more complex co-cultures of primary or stem cell-derived liver cells. Great progress has been made in the development of stem cell-derived liver cultures; however, the liver cells obtained from stem cells do not yet...

Terminally differentiated cells are regarded as the most stable and common cell state in adult organisms as they reside in growth arrest and carry out their cellular function. Improving our understanding of the mechanisms involved in promoting cell cycle exit would facilitate our ability to manipulate pluripotent cells into mature tissues for both...

Objectives: Hepatocytic CEACAM1 plays a critical role in NASH pathogenesis, as bolstered by the development of insulin resistance, visceral obesity, steatohepatitis and fibrosis in mice with global Ceacam1 (Cc1) deletion. In contrast, VECadCre+Cc1fl/fl mice with endothelial loss of Cc1 manifested insulin sensitivity with no visceral obesity despit...

The Hippo signaling pathway is widely considered a master regulator of organ growth because of the prominent overgrowth phenotypes caused by experimental manipulation of its activity. Contrary to this model, we show here that removing Hippo transcriptional output did not impair the ability of the mouse liver and Drosophila eyes to grow to their nor...

Transcriptomics-based biomarkers are promising new approach methodologies (NAMs) to identify molecular events underlying the genotoxic mode of action of chemicals. Previously, we developed the GENOMARK biomarker, consisting of 84 genes selected based on whole genomics DNA microarray profiles of 24 (non-)genotoxic reference chemicals covering differ...

Chronic liver disease can lead to liver fibrosis and ultimately cirrhosis, which is a significant health burden and a major cause of death worldwide. Reliable in vitro models are lacking and thus mono-cultures of cell lines are still used to study liver disease and evaluate candidate anti-fibrotic drugs. We established functional multicellular live...

In vitro models of human liver disease often fail to mimic the complex 3D structures and cellular organizations found in vivo . Precision cut liver slices (PCLS) retain the complex physiological architecture of the native liver and therefore could be an exceptional in vitro liver model. However, the production of PCLS induces a spontaneous culture-...

Prediction of chemical toxicity is very useful in risk assessment. With the current paradigm shift towards the use of in vitro and in silico systems, we present herein a theoretical mathematical description of a quasi-diffusion process to predict chemical concentrations in 3-D spheroid cell cultures. By extending a 2-D Virtual Cell Based Assay (VCB...

Scoring of tumor-infiltrating lymphocytes (TILs) in breast cancer specimens has gained increasing attention, as TILs have prognostic and predictive value in HER2⁺ and triple-negative breast cancer. We evaluated the intra- and interrater variability when scoring TILs by visual inspection of hematoxylin and eosin-stained tissue sections. We further a...

Activated hepatic stellate cells (aHSC) are the main source of extra cellular matrix in liver fibrosis. Activation is classically divided in two phases: initiation and perpetuation. Currently, HSC-based therapeutic candidates largely focus on targeting the aHSCs in the perpetuation phase. However, the importance of HSC initiation during chronic liv...

Liver sinusoidal endothelial cells have a gatekeeper function in liver homeostasis by permitting substrates from the bloodstream into the space of Disse and regulating hepatic stellate cell activation status. Maintenance of LSEC's highly specialized phenotype is crucial for liver homeostasis. During liver fibrosis and cirrhosis, LSEC phenotype and...

Thirty-five years ago, precision-cut liver slices (PCLS) were described as a promising tool and were expected to become the standard in vitro model to study liver disease as they tick off all characteristics of a good in vitro model. In contrast to most in vitro models, PCLS retain the complex 3D liver structures found in vivo, including cell–cell...

Chronic liver injury, as observed in non-alcoholic steatohepatitis (NASH), progressive fibrosis, and cirrhosis, remains poorly treatable. Steatohepatitis causes hepatocyte loss in part by a direct lipotoxic insult, which is amplified by derangements in the non-parenchymal cellular (NPC) interactive network wherein hepatocytes reside, including, hep...

Sepsis is a potentially lethal syndrome resulting from a maladaptive response to infection. Upon infection, glucocorticoids are produced as a part of the compensatory response to tolerate sepsis. This tolerance is, however, mitigated in sepsis due to a quickly induced glucocorticoid resistance at the level of the glucocorticoid receptor. Here, we s...

There is an unmet need for functional primary human hepatocytes to support the pharmaceutical and (bio)medical demand. The unique discovery, a decade ago, that somatic cells can be drawn out of their seemingly biological lockdown to acquire once again a pluripotent state, has paved a complete new avenue of possibilities to generate surrogate human...

Aims: Hepatic capillaries are lined with specialised liver sinusoidal endothelial cells (LSECs) which support macromolecule passage to hepatocytes and prevent fibrosis by keeping hepatic stellate cells (HSCs) quiescent. LSEC specialisation is co-determined by transcription factors. The Zinc-Finger E-Box-binding Homeobox (Zeb)2 transcription factor...

Hepatic stellate cells (HSCs) are nonparenchymal liver cells responsible for extracellular matrix homeostasis and are the main cells involved in the development of liver fibrosis following injury. The lack of reliable sources of HSCs has hence limited the development of complex in vitro systems to model liver diseases and toxicity. Here we describe...

To date, there is no representative in vitro model for liver sinusoidal endothelial cells (LSECs), as primary LSECs dedifferentiate very fast in culture and no combination of cytokines or growth factors can induce an LSEC fate in (pluripotent stem cell (PSC)-derived) endothelial cells (ECs). Furthermore, the transcriptional programmes driving an LS...

Background and aims The Hippo pathway and its downstream effectors YAP and TAZ (YAP/TAZ) are heralded as important regulators of organ growth and regeneration. However, different studies provided contradictory conclusions about their role during regeneration of different organs ranging from promoting proliferation to inhibiting it. Here, we resolve...

Chronic liver injury, as observed in non-alcoholic steatohepatitis (NASH), progressive fibrosis, and cirrhosis, remains poorly treatable. Steatohepatitis causes hepatocyte loss in part by a direct lipotoxic insult, which is amplified by derangements in the non-parenchymal cellular (NPC) interactive network wherein hepatocytes reside, including, hep...

To date there is no representative in vitro model for liver sinusoidal endothelial cells (LSECs), as primary LSECs dedifferentiate very fast in culture and no combination of cytokines or growth factors can induce an LSEC fate in (pluripotent stem cell-derived) endothelial cells (ECs). Furthermore, the transcriptional programs driving an LSEC fate h...

A major obstacle in the development of efficient therapies for progressive liver fibrosis is the lack of representative in vitro models of liver fibrosis to aid in understanding the mechanisms of the disease and to promote the development of pharmaceuticals. Our aim was to develop a relevant in vitro mouse liver fibrosis model, based on the central...

Introduction Chronic liver disease is due to various causes of persistent liver damage and will eventually lead to the development of liver fibrosis. If no treatment is initiated, this condition may progress to cirrhosis and hepatocellular carcinoma. Current treatments comprise the elimination of the cause of injury, such as by lifestyle changes, a...

Mixed signals at tumor margins The Hippo signaling pathway has been implicated in tumor growth, sparking interest in the pathway as a potential therapeutic target. In a study of liver cancer in genetically manipulated mice, Moya et al. discovered that the role of this pathway in tumorigenesis is more complex than previously appreciated. They confir...

Macrophages are strongly adapted to their tissue of residence. Yet, little is known about the cell-cell interactions that imprint the tissue-specific identities of macrophages in their respective niches. Using conditional depletion of liver Kupffer cells, we traced the developmental stages of monocytes differentiating into Kupffer cells and mapped...

Background: Chronic liver diseases are frequently accompanied with activation of biliary epithelial cells (BECs) that can differentiate into hepatocytes and cholangiocytes, providing an endogenous back-up system. Functional studies on BECs often rely on isolations of an BEC cell population from healthy and/or injured livers. However, a consensus o...

Background: The current diagnosis of early-stage liver fibrosis often relies on a serological or imaging-based evaluation of the stage of fibrosis, sometimes followed by an invasive liver biopsy procedure. Novel non-invasive experimental diagnostic tools are often based on markers of hepatocyte damage, or changes in liver stiffness and architecture...

Inducible cyclization recombinase (Cre) transgenic mouse strains are powerful tools for cell lineage tracing and tissue-specific knockout experiments. However, low efficiency or leaky expression can be important pitfalls. Here, we compared the efficiency and specificity of two commonly used cholangiocyte-specific Cre drivers, the Opn-iCreERT2 and C...

Background: Platelet Derived Growth Factor Receptor beta (PDGFRβ) has been associated to hepatic stellate cell activation and has been the target of multiple therapeutic studies. However, little is known concerning its use as a diagnostic agent. Methods: Circulating PDGFRβ levels were analysed in a cohort of patients with liver fibrosis/cirrhosi...

Mesenchymal stromal cells (MSCs) are promising tools in regenerative medicine and targeted therapies. Although different origins have been described, there is still huge need to find a valuable source harboring specific subpopulations of MSCs with precise therapeutic functions. Here, we isolated by fluorescence activated cell sorting technique, two...

Hepatic stellate cells activate upon liver injury and help at restoring damaged tissue by producing extracellular matrix proteins. A drastic increase in matrix proteins results in liver fibrosis and we hypothesize that this sudden increase leads to accumulation of proteins in the endoplasmic reticulum and its compensatory mechanism, the unfolded pr...

Background & aim: Chronic liver diseases are characterized by expansion of the small immature cholangiocytes - a mechanism named ductular reaction (DR) - which have the capacity to differentiate into hepatocytes. We investigated the kinetics of this differentiation, as well as analyzing several important features of the newly formed hepatocytes, s...

P311 was first identified by the group of Studler et al. (1993) in the developing brain. In healthy, but mainly in pathological tissues, P311 is implicated in cell migration and proliferation. Furthermore, evidence in models of tissue fibrosis points to the colocalization with and the stimulation of transforming growth factor β1 by P311. This revie...

Thanks to their relative abundance and easier collection, adipose tissue (AT) is considered an alternative source for the isolation of mesenchymal stromal cells (MSCs). MSCs have great therapeutic values and are thus under investigations for several clinical indications such as regenerative medicine and immunomodulation. In this work, we aimed to i...

The development of complex in vitro hepatic systems and artificial liver devices has been hampered by the lack of reliable sources for relevant cell types, such as hepatic stellate cells (HSCs). Here we report efficient differentiation of human pluripotent stem cells into HSC-like cells (iPSC-HSCs). iPSC-HSCs closely resemble primary human HSCs at...

Background: Mesenchymal stromal cells (MSCs) become an attractive research topic because of their crucial roles in tissue repair and regenerative medicine. Foreskin is considered as a valuable tissue source containing immunotherapeutic MSCs (FSK-MSCs). Results: In this work, we used aldehyde dehydrogenase activity (ALDH) assay (ALDEFLUOR™) to is...

Liver fibrosis is the result of persistent liver injury, and is characterized by sustained scar formation and disruption of the normal liver architecture. The extent of fibrosis is considered as an important prognostic factor for the patient outcome, as an absence of (early) treatment can lead to the development of liver cirrhosis and hepatocellula...

RAS mutations occur frequently in multiple myeloma (MM), but apart from driving progression, they can also stimulate antitumor effects by activating tumor-suppressive RASSF proteins. Although this family of death effector molecules are often silenced in cancers, functional data about RASSF proteins in MM are lacking. Here, we report that RASSF4 is...

Mesenchymal stromal cells (MSCs) have particular properties that allow their use as therapeutic strategies for several cell-based applications. Historically, bone marrow (BM)-MSCs are isolated by culture adherence since specific cell surface markers are yet to be developed. This original work aimed to identify and characterize isolating expanded BM...

Human hepatic stellate cells (HSCs) demonstrated great immunological plasticity with important consequences for liver cell therapy. Activated HSCs (aHSCs) are in vitro reverted (rHSCs) to a quiescent-like phenotype with potential benefit to reduce liver fibrosis. The goal of this study is to establish and compare the immunological profile of activa...

Pannexins are transmembrane proteins that form communication channels connecting the cytosol of an individual cell with its extracellular environment. A number of studies have documented the presence of pannexin1 in liver as well as its involvement in inflammatory responses. In this study, it was investigated whether pannexin1 plays a role in acute...

Hepatic progenitor cells (HPCs) are small cells with a relative large oval nucleus and a scanty cytoplasm situated in the canals of Hering that express markers of (immature) hepatocytes and cholangiocytes. HPCs are present in large numbers in alcoholic steatohepatitis (ASH), one of the leading causes of chronic liver disease. To date, the mechanism...

We describe and illustrate a workflow for chemical safety assessment that completely avoids animal testing. The workflow, which was developed within the SEURAT-1 initiative, is designed to be applicable to cosmetic ingredients as well as to other types of chemicals, e.g. active ingredients in plant protection products, biocides or pharmaceuticals....