Biology subjects

Calitz, C.

Publications and source records attributed to Calitz, C..

5 recordsLinked to original sources

bioRxiv2024

A Human Biomimetic Intestinal Mucosa Model to Study Gastrointestinal Development and Disease

The intestinal mucosa plays a vital role in nutrient absorption, drug metabolism, and pathogen defence. Advances in single-cell technologies have highlighted the specialised roles of various cell types that execute these diverse functions. Aside from intestinal epithelial cells, fibroblasts play an essential role in regulating the extracellular matrix and controlling pro- inflammatory signalling, and antigen-presenting cells (macrophages and dendritic cells) maintain intestinal homeostasis and immune responses. The incorporation of such cellular complexity within the existing in vitro models of the human intestine is currently challenging. To address this, we developed a human intestinal model that accurately mimics the mucosal cellular environment comprising intestinal epithelial cells, intestinal fibroblasts, and antigen presenting cells. This model includes co-cultures of adult and foetal cells, facilitating studies on barrier function, inflammation, and viral infections. It replicates extracellular matrix deposition, Paneth cell differentiation, immune interactions, and can be used to model host- pathogen interactions. Our advanced co-culture model improves the physiological relevance of in vitro studies, enabling the exploration of epithelial-mesenchymal-immune crosstalk and its role in intestinal health and disease.

cell biology↗

bioRxiv2023

Assessment of The Broad-Spectrum Host Targeting Antiviral Efficacy of Halofuginone Hydrobromide in Human Airway, Intestinal and Brain Organoid Models.

Halofuginone hydrobromide has shown potent antiviral efficacy against a variety of viruses such as SARS-CoV-2, dengue, or chikungunya virus, and has, therefore, been hypothesized to have broad-spectrum antiviral activity. In this paper, we tested this broad-spectrum antiviral activity of Halofuginone hydrobomide against viruses from different families (Picornaviridae, Herpesviridae, Orthomyxoviridae, Coronaviridae, and Flaviviridae). To this end, we used relevant human models of the airway and intestinal epithelium and regionalised neural organoids. Halofuginone hydrobomide showed antiviral activity against SARS-CoV-2 in the airway epithelium with no toxicity at equivalent concentrations used in human clinical trials but not against any of the other tested viruses. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=199 HEIGHT=200 SRC="FIGDIR/small/565121v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@10d562eorg.highwire.dtl.DTLVardef@94f903org.highwire.dtl.DTLVardef@683b6forg.highwire.dtl.DTLVardef@11620ba_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIHalofuginone hydrobromide was identified as a possible broad-spectrum host targeting antiviral drug. C_LIO_LIHuman organoid models offer a physiologically relevant and clinically translatable model for antiviral research. C_LIO_LIHalofuginone hydrobromide shows antiviral efficacy against SARS-CoV-2, but not against EV-A71, PeV-A1, IAV, RV-A16, HCMV or ZIKV in relevant organoid models. C_LIO_LIThe efficacy of Halofuginone hydrobromide is concentration dependent as well as on proline content of the host receptor(s) or host factors for the specific virus in question. C_LI

microbiology↗

bioRxiv2021

Anthracyclins increase free PUFAs and etherPEs with PUFAs as potential hallmarks of lipid peroxidation and ferroptosis

Metabolic and personalized interventions in cancer treatment require a better under-standing of the relationship between the induction of cell death and metabolism. Consequently, we treated three primary liver cancer cell lines with two anthracyclins (doxorubicin and idarubin) and studied the changes of the lipidome. We found that both anthracyclins in the three cell lines increased the levels of polyunsaturated fatty acids (PUFAs) and alkylacylglycerophosphoethano-lamines (etherPEs) with PUFAs. As PUFAs and alkylacylglycerophospholipids with PUFAs are fundamental in lipid peroxidation during ferroptotic cell death, our results suggests supplementa-tion with PUFAs and/or etherPEs with PUFAs as a potential general adjuvant of anthracyclins. In contrast, neither the markers of de novo lipogenesis nor cholesterol lipids presented the same trend in all cell lines and treatments. In agreement with previous research, this suggests that modulation of the metabolism of cholesterol could be considered a specific adjuvant of anthracyclins depend-ing on the type of tumor and the individual. Finally, we discuss the changes in the lipidome in re-lation to the endoplasmic reticulum stress and the sensitivity to anthracyclins of the different cells. In conclusion, our results suggest that the modulation of different lipid metabolic pathways may be considered for generalized and personalized metabochemotherapies.

cancer biology↗

bioRxiv2020

A biomimetic liver model recapitulating bio-physical properties and tumour stroma interactions in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary liver tumor developing in the wake of chronic liver disease. Chronic liver disease and inflammation leads to a fibrotic environment actively supporting and driving hepatocarcinogenesis. Insight into hepatocarcinogenesis in terms of the interplay between the tumor stroma micro-environment and tumor cells is thus of considerable importance. Three-dimensional (3D) cell culture models are proposed as the missing link between current in vitro 2D cell culture models and in vivo animal models. Our aim was to design a novel 3D biomimetic HCC model with accompanying fibrotic stromal compartment and vasculature. Physiologically relevant hydrogels such as collagen and fibrinogen were incorporated to mimicking the bio-physical properties of the tumor ECM. In our model LX2 and HepG2 cells embedded in a hydrogel matrix were seeded onto the inverted insert membrane of a Transwell system. HUVEC cells were then seeded onto the opposite side of the membrane. Three formulations consisting of ECM-hydrogels embedded with cells were prepared and the bio-physical properties determined by rheology. Cell viability was determined by the AlamarBlue(R) assay over 21-days. The effect of the chemotherapeutic drug doxorubicin was evaluated in both a 2D co-culture and our 3D model for a period of 72h. We show that this model is viable for 25-days and gives rise to metastatic tumor nodules after 17 days in culture. Rheology results show that bio-physical properties of a fibrotic, cirrhotic and HCC liver can be successfully mimicked. Overall, results indicate that this 3D model is more representative of the in vivo situation compared to traditional 2D cultures. Our 3D tumor model showed a decreased response to chemotherapeutics, mimicking drug resistance typically seen in HCC patients. This model could in future provide a valuable new platform to study multifocal HCC or to identify mechanisms that contribute to early stages of metastasis. SUMMARYA protocol for a novel 3D biomimetic HCC model with accompanying fibrotic stromal compartment and vasculature, to study endocrine and paracrine signaling in liver cancer. The model uses physiological relevant hydrogels in ratios mimicking the bio-physical properties of the stromal extracellular matrix, which is an active mediator of cellular interactions, tumor growth and metastasis.

cancer biology↗

bioRxiv2019

Fibrin fragment E potentiates TGF-β-induced myofibroblast activation and recruitment

BackgroundFibrin is an essential constituent of the coagulation cascade, and the formation of hemostatic fibrin clots is central to wound healing. Fibrin clots are over time degraded into fibrin degradation products as the injured tissue is replaced by granulation tissue.\n\nObjectivesstudy the role of the fibrin degradation product fragment E (FnE) in fibroblast activation and migration.\n\nMethodsRat kidney fibroblasts (NRK-49F), human fetal lung fibroblasts (HFL1) and immortalized human foreskin fibroblasts (BJ) were exposed to FnE and TGF-{beta}. Fibroblast activation was measured via quantitative RT-PCR and western blot for -SMA and Collagen I1. A microfluidic chemotaxis assay was used to study directional migration. To investigate if FnE interacts with integrins, direct binding experiments were performed using surface plasmon resonance biosensor technology. Infusion pumps releasing FnE were implanted subcutaneously in mice and profibrotic effects of FnE were analyzed using immunohistochemical staining of the wound area.\n\nResultsWe present evidence that FnE is a chemoattractant for fibroblasts and that FnE can potentiate TGF-{beta}-induced myofibroblast formation. FnE forms a stable complex with V{beta}3 integrin, and the integrin {beta}3 subunit is required both for FnE-induced fibroblast migration and for potentiation of TGF-{beta}-induced myofibroblast formation. Finally, subcutaneous infusion of FnE in mice results in a fibrotic response in the hypodermis. These results support a model where FnE released from clots in wounded tissue promote wound healing and fibrosis by both recruitment and activation of fibroblasts. Fibrin fragment E could thus represent a therapeutic target for treatment of pathological fibrosis.\n\nEssentials- Fibrin is an essential constituent of the coagulation cascade, and fibrin clotting is central to wound healing.\n- Fibrin clots are over time degraded into fibrin degradation products, including fibrin fragment E (FnE).\n- FnE is a chemoattractant for fibroblasts and can potentiate TGF-{beta}-induced myofibroblast formation.\n- FnE released from clots in wounded tissue could promote wound healing and fibrosis.

cell biology↗