Catherine Anne Heyward

• Demir, Ali Aslan; Combriat, Thomas Michel Daniel; Heyward, Catherine Anne; Tiainen, Hanna; Carlier, Aurélie & Dysthe, Dag Kristian (2026). A cellular automaton model of osteogenic differentiation reveals identifiability limits of endpoint assays. Frontiers in Systems Biology. 6. doi: 10.3389/fsysb.2026.1872774. Fulltekst i vitenarkiv Vis sammendrag

  Introduction Standard differentiation assays sample cell states only at discrete time points, while the underlying progression unfolds continuously and heterogeneously across cells. As a result, different combinations of proliferation, commitment, and maturation dynamics can converge to similar endpoint measurements. This many-to-one mapping between latent trajectories and observable readouts constitutes a partially observed inverse problem that limits mechanistic interpretation. Although this ambiguity is inherent to many experimental systems, it is rarely examined using models that connect cell-state dynamics to assay-level quantities. Methods We present OsteoMin, a coarse-grained cellular automaton that links stochastic transitions between pre-osteoblast and osteoblast states to experimentally measurable readouts of alkaline phosphatase activity, collagen deposition, and mineralization. Model parameters were constrained using literature-reported kinetics and evaluated against dexamethasone and menaquinone-4 perturbations. The framework enables systematic analysis of how cell-state progression, matrix maturation, and external perturbations shape differentiation outcomes. Results OsteoMin reproduces qualitative assay trends and quantifies the identifiability limits of endpoint assays. Distinct perturbation families often produce similar endpoint responses (macro-F1 ≈ 0.42$), indicating limited discriminative power. Incorporating temporal trajectories improves separability (macro-F1 ≈ 0.78$), demonstrating that most identifiable information resides in marker dynamics rather than terminal measurements. Sobol analysis shows that early markers depend on proliferation timing, whereas late mineralization is governed by nonlinear matrix maturation and parameter interactions. Discussion These results show that endpoint assays constrain overall progression but do not uniquely identify underlying mechanisms. OsteoMin provides a framework linking differentiation dynamics to assay observables and a basis for assessing identifiability in endpoint-driven systems.

• Hildebrand, Torben; Ma, Qianli; Heyward, Catherine Anne; Haugen, Håvard Jostein & Nogueira, Liebert Parreiras (2024). Advanced soft tissue visualization in conjunction with bone structures using contrast-enhanced micro-CT. Journal of Medical Imaging. ISSN 2329-4302. 11(6). doi: 10.1117/1.JMI.11.6.066001. Fulltekst i vitenarkiv Vis sammendrag

  Purpose: Micro-CT analysis of soft tissues alongside bone remains challenging due to significant differences in X-ray absorption, preventing spatial inspection of bone remodeling including the cellular intricacies of mineralized tissues in developmental biology and pathology. The goal was to develop a protocol for contrast-enhanced micro-CT imaging that effectively visualizes soft tissues and cells in conjunction with bone while minimizing bone attenuation by decalcification. Approach: Murine femur samples were decalcified in EDTA and treated with three different contrast agents: i) iodine in ethanol, ii) PTA in water, and iii) Lugol’s iodine. Micro-CT scans were performed in the laboratory set-up SkyScan 1172 and at the SYRMEP beamline in ELETTRA. Soft- and hard-tissue contrast-to-noise ratio (CNR) and contrast efficiency after decalcification were measured. Results: In laboratory micro-CT, Lugol’s iodine demonstrated a three-times higher CNR in bone marrow, representing the soft tissue portion, compared to bone. Contrast efficiencies, measured in synchrotron micro-CT, were consistent with these findings. Higher resolutions and the specificity of Lugol’s iodine to cellular structures enabled detailed visualization of bone-forming cells in the epiphyseal plate. Conclusions: The combination of decalcification and the utilization of the contrast agent Lugol’s iodine facilitated an enhanced soft tissue visualization in conjunction with bone.

• Yang, Yang; Geng, Tianxiang; Samara, Athina; Olstad, Ole Kristoffer; He, Jianying & Agger, Anne Eriksson [Vis alle 11 forfattere av denne artikkelen] (2023). Recombinant irisin enhances the extracellular matrix formation, remodeling potential, and differentiation of human periodontal ligament cells cultured in 3D. Journal of Periodontal Research. ISSN 0022-3484. 58(2), s. 336–349. doi: 10.1111/jre.13094. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Background Irisin is expressed in human periodontal ligament (hPDL), and its administration enhances growth, migration and matrix deposition in hPDL cells cultured in monolayers in vitro. Objectives To identify whether irisin affects the gene expression patterns directing the morphology, mechanical properties, extracellular matrix (ECM) formation, osteogenic activity and angiogenic potential in hPDL cell spheroids cultured in 3D. Materials and Methods Spheroids of primary human hPDL cells were generated in a rotational 3D culture system and treated with or without irisin. The gene expression patterns were evaluated by Affymetrix microarrays. The morphology of the spheroids was characterized using histological staining. Mechanical properties were quantified by nanoindentation. The osteogenic and angiogenic potential of spheroids were assessed through immunofluorescence staining for collagen type I, periostin fibronectin and von Willebrand factor (vWF), and mRNA expression of osteogenic markers. The secretion of multiple myokines was evaluated using Luminex immunoassays. Results Approximately 1000 genes were differentially expressed between control and irisin-treated groups by Affymetrix. Several genes related to ECM organization were differentially expressed, and multiple deubiquitinating enzymes were upregulated in the irisin-exposed samples analyzed. These represent cellular and molecular mechanisms indicative of a role for irisin in tissue remodeling. Irisin induced a rim-like structure on the outer region of the hPDL spheroids, ECM-related protein expression and the stiffness of the spheroids were enhanced by irisin. The expression of osteogenic and angiogenetic markers was increased by irisin. Conclusions Irisin altered the morphology in primary hPDL cell-derived spheroids, enhanced its ECM deposition, mechanical properties, differentiation and remodeling potential.

• Reseland, Janne Elin; Heyward, Catherine Anne & Samara, Athina (2023). Revisiting ameloblastin; addressing the EMT-ECM axis above and beyond oral biology. Frontiers in Cell and Developmental Biology. 11. doi: 10.3389/fcell.2023.1251540. Fulltekst i vitenarkiv Vis sammendrag

  Ameloblastin (AMBN) is best characterized for its role in dental enamel formation, regulating cell differentiation and mineralization, and cell matrix adhesion. However, AMBN has also been detected in mesenchymal stem cells in addition to bone, blood, and adipose tissue. Using immunofluorescence in a pilot scheme, we identified that AMBN is expressed in different parts of the gastrointestinal (GI) tract. AMBN mRNA and protein detection in several tissues along the length of the GI tract suggests a role for AMBN in the structure and tissue integrity of the extracellular matrix (ECM). Intracellular AMBN expression in subsets of cells indicates a potential alternative role in signaling processes. Of note, our previous functional AMBN promoter analyses had shown that it contains epithelial–mesenchymal transition (EMT) regulatory elements. ΑΜΒΝ is herein presented as a paradigm shift of the possible associations and the spatiotemporal regulation of the ECM regulating the EMT and vice versa, using the example of AMBN expression beyond oral biology.

• Tien, Nguyen D.; Geng, Tianxiang; Heyward, Catherine Anne; Reseland, Janne Elin; Lyngstadaas, Ståle Petter & Blaker, Jonathan James [Vis alle 7 forfattere av denne artikkelen] (2022). Solution blow spinning of highly deacetylated chitosan nanofiber scaffolds for dermal wound healing. Materials Science and Engineering C: Materials for Biological Applications. ISSN 0928-4931. 137. doi: 10.1016/j.bioadv.2022.212871. Fulltekst i vitenarkiv Vis sammendrag

  Biocompatible fibrous scaffolds based on highly deacetylated chitosan were fabricated using high-throughput solution blow spinning. Scanning electron microscopy analysis revealed that the chitosan nanofiber scaffolds had ultrafine and continuous fibers (300–1200 nm) with highly interconnected porous structures (30–75% porosity), mimicking some aspects of the native extracellular matrix in skin tissue. Post-treatment of as-spun nanofibers with aqueous potassium carbonate solution resulted in a fibrous scaffold with a high chitosan content that retained its fibrous structural integrity for cell culture. Analysis of the mechanical properties of the chitosan nanofiber scaffolds in both dry and wet conditions showed that their strength and durability were sufficient for wound dressing applications. Significantly, the wet scaffold underwent remarkable elastic deformation during stretch such that the elongation at break dramatically increased to up to 44% of its original length, showing wavy fiber morphology near the break site. The culture of normal human dermal fibroblast cells onto scaffolds for 1–14 days demonstrated that the scaffolds were highly compatible and a suitable platform for cell adhesion, viability, and proliferation. Secretion profiles of wound healing-related proteins to the cell culture medium demonstrated that chitosan fibers were a promising scaffold for wound healing applications. Overall, the dense fibrous network with high porosity of the chitosan nanofiber scaffold and their mechanical properties indicate that they could be used to design and fabricate new materials that mimic the epidermis layer of natural skin.

• Geng, Tianxiang; Heyward, Catherine Anne; Chen, Xi; Zheng, Mengxue; Yang, Yang & Reseland, Janne Elin (2022). Comprehensive Analysis Identifies Ameloblastin-Related Competitive Endogenous RNA as a Prognostic Biomarker for Testicular Germ Cell Tumour. Cancers. 14(8). doi: 10.3390/cancers14081870. Fulltekst i vitenarkiv
• Yang, Yang; Pullisaar, Helen; Landin, Maria Augusta Dos S Silva; Heyward, Catherine Anne; Schröder, Maria & Geng, Tianxiang [Vis alle 8 forfattere av denne artikkelen] (2021). FNDC5/irisin is expressed and regulated differently in human periodontal ligament cells, dental pulp stem cells and osteoblasts. Archives of Oral Biology. ISSN 0003-9969. doi: 10.1016/j.archoralbio.2021.105061. Fulltekst i vitenarkiv Vis sammendrag

  Objective To examine the expression and regulation of fibronectin type III domain-containing protein 5/irisin (FNDC5/irisin) in primary human periodontal ligament (hPDL) cells, dental pulp stem cells (hDPCs) and osteoblasts (hOBs). Methods FNDC5/irisin was identified in sections of paraffin embedded rat maxillae, cryo-sections of 3D cultured spheroids hPDL cells, hDPCs and hOBs, 2D cultured hPDL cells, hDPCs and hOBs by immunohistochemistry. The expression of FNDC5/irisin was identified by qPCR, followed by sequencing of the qPCR product. Regulation of FNDC5/irisin expression in hPDL cells, hDPCs and hOBs were evaluated after administration of different concentrations of irisin and all-trans retinoic acid (ATRA). qPCR and ELISA were used to identify expression and secretion of FNDC5/irisin in odontoblast-like differentiation of hDPCs. Results FNDC5/irisin was confirmed to be present in rat periodontium and dental pulp regions, as well as in 2D and 3D cultured hPDL cells, hDPCs and hOBs. BLAST analyses verified the generated nucleotide alignments matched human FNDC5/irisin. FNDC5/irisin gene expression was enhanced during odontoblast-like differentiation of hDPCs whereas the secretion of the protein was decreased compared to control. The protein signals in rat periodontal and pulpal tissues were higher than that of alveolar bone, and the expression of FNDC5/irisin was differently regulated by recombinant irisin and ATRA in hPDL cells and hDPCs compared to hOBs. Conclusions FNDC5/irisin expression was verified in rodent periodontium and dental pulp, and in hPDL cells, hDPCs and hOBs. The FNDC5/irisin expression was regulated by recombinant irisin and ATRA. Finally, expression and secretion of FNDC5/irisin were affected during odontoblast-like differentiation of hDPCs.

• Rahmati, Maryam; Silva, Eduardo A.; Reseland, Janne Elin; Heyward, Catherine Anne & Haugen, Håvard Jostein (2020). Biological responses to physicochemical properties of biomaterial surface. Chemical Society Reviews. ISSN 0306-0012. 49(15), s. 5178–5224. doi: 10.1039/d0cs00103a. Fulltekst i vitenarkiv Vis sammendrag

  Biomedical scientists use chemistry-driven processes found in nature as an inspiration to design biomaterials as promising diagnostic tools, therapeutic solutions, or tissue substitutes. While substantial consideration is devoted to the design and validation of biomaterials, the nature of their interactions with the surrounding biological microenvironment is commonly neglected. This gap of knowledge could be owing to our poor understanding of biochemical signaling pathways, lack of reliable techniques for designing biomaterials with optimal physicochemical properties, and/or poor stability of biomaterial properties after implantation. The success of host responses to biomaterials, known as biocompatibility, depends on chemical principles as the root of both cell signaling pathways in the body and how the biomaterial surface is designed. Most of the current review papers have discussed chemical engineering and biological principles of designing biomaterials as separate topics, which has resulted in neglecting the main role of chemistry in this field. In this review, we discuss biocompatibility in the context of chemistry, what it is and how to assess it, while describing contributions from both biochemical cues and biomaterials as well as the means of harmonizing them. We address both biochemical signal-transduction pathways and engineering principles of designing a biomaterial with an emphasis on its surface physicochemistry. As we aim to show the role of chemistry in the crosstalk between the surface physicochemical properties and body responses, we concisely highlight the main biochemical signal-transduction pathways involved in the biocompatibility complex. Finally, we discuss the progress and challenges associated with the current strategies used for improving the chemical and physical interactions between cells and biomaterial surface.

• Ganan, Monica; Lorentzen, Silje Benedicte; Agger, Jane Wittrup; Heyward, Catherine Anne; Bakke, Oddmund & Knutsen, Svein Halvor [Vis alle 10 forfattere av denne artikkelen] (2019). Antifungal activity of well-defined chitooligosaccharide preparations against medically relevant yeasts. PLOS ONE. 14(1). doi: 10.1371/journal.pone.0210208. Fulltekst i vitenarkiv Vis sammendrag

  Due to their antifungal activity, chitosan and its derivatives have potential to be used for treating yeast infections in humans. However, to be considered for use in human medicine, it is necessary to control and know the chemical composition of the compound, which is not always the case for polymeric chitosans. Here, we analyze the antifungal activity of a soluble and well-defined chito-oligosaccharide (CHOS) with an average polymerization degree (DPn) of 32 and fraction of acetylation (FA) of 0.15 (C32) on 52 medically relevant yeast strains. Minimal inhibitory concentrations (MIC) varied widely among yeast species, strains and isolates (from > 5000 to < 9.77 μg mL-1) and inhibition patterns showed a time- and dose-dependencies. The antifungal activity was predominantly fungicidal and was inversely proportional to the pH, being maximal at pH 4.5, the lowest tested pH. Furthermore, antifungal effects of CHOS fractions with varying average molecular weight indicated that those fractions with an intermediate degree of polymerization, i.e. DP 31 and 54, had the strongest inhibitory effects. Confocal imaging showed that C32 adsorbs to the cell surface, with subsequent cell disruption and accumulation of C32 in the cytoplasm. Thus, C32 has potential to be used as a therapy for fungal infections.

• Chahal, Aman Singh; Schweikle, Manuel; Heyward, Catherine Anne & Tiainen, Hanna (2018). Attachment and spatial organisation of human mesenchymal stem cells on poly(ethylene glycol) hydrogels. Journal of The Mechanical Behavior of Biomedical Materials. ISSN 1751-6161. 84, s. 46–53. doi: 10.1016/j.jmbbm.2018.04.025. Fulltekst i vitenarkiv Vis sammendrag

  Strategies that enable hydrogel substrates to support cell attachment typically incorporate either entire extracellular matrix proteins or synthetic peptide fragments such as the RGD (arginine–glycine–aspartic acid) motif. Previous studies have carefully analysed how material characteristics can affect single cell morphologies. However, the influence of substrate stiffness and ligand presentation on the spatial organisation of human mesenchymal stem cells (hMSCs) have not yet been examined. In this study, we assessed how hMSCs organise themselves on soft (E = 7.4–11.2 kPa) and stiff (E = 27.3–36.8 kPa) poly(ethylene glycol) (PEG) hydrogels with varying concentrations of RGD (0.05–2.5 mM). Our results indicate that hMSCs seeded on soft hydrogels clustered with reduced cell attachment and spreading area, irrespective of RGD concentration and isoform. On stiff hydrogels, in contrast, cells spread with high spatial coverage for RGD concentrations of 0.5 mM or higher. In conclusion, we identified that an interplay of hydrogel stiffness and the availability of cell attachment motifs are important factors in regulating hMSC organisation on PEG hydrogels. Understanding how cells initially interact and colonise the surface of this material is a fundamental prerequisite for the design of controlled platforms for tissue engineering and mechanobiology studies.

• Stakkestad, Øystein; Heyward, Catherine Anne; Lyngstadaas, Ståle Petter; Medin, Tirill; Vondrasek, Jiri & Lian, Aina-Mari [Vis alle 8 forfattere av denne artikkelen] (2018). An ameloblastin C-terminus variant is present in human adipose tissue. Heliyon. 4(12). doi: 10.1016/j.heliyon.2018.e01075. Fulltekst i vitenarkiv Vis sammendrag

  Objective: Transcriptional regulatory elements in the ameloblastin (AMBN) promoter indicate that adipogenesis may influence its expression. The objective here was to investigate if AMBN is expressed in adipose tissue, and have a role during differentiation of adipocytes. Design: AMBN expression was examined in adipose tissue and adipocytes by real-time PCR and ELISA. Distribution of ameloblastin was investigated by immunofluorescence in sections of human subcutaneous adipose tissue. The effect of recombinant proteins resembling AMBN and its processed products on proliferation of primary human pre-adipocytes and murine 3T3-L1 cell lines was measured by [3H]-thymidine incorporation. The effect on adipocyte differentiation was evaluated by the expression profile of the adipogenic markers PPARγ and leptin, and the content of lipids droplets (Oil-Red-O staining). Results: AMBN was found to be expressed in human adipose tissue, human primary adipocytes, and in 3T3-L1 cells. The C-terminus of the AMBN protein and a 45 bp shorter splice variant was identified in human subcutaneous adipose tissue. The expression of AMBN was found to increase four-fold during differentiation of 3T3-L1 cells. Administration of recombinant AMBN reduced the proliferation, and enhanced the expression of PPARγ and leptin in 3T3-L1 and human pre-adipocytes, respectively. Conclusions: The AMBN C-terminus variant was identified in adipocytes. This variant may be encoded from a short splice variant. Increased expression of AMBN during adipogenesis and its effect on adipogenic factors suggests that AMBN also has a role in adipocyte development.

Se alle arbeider i NVA

• Ernø, Inger Thea Myklebust; Zaytseva-Zotova, Daria; Heyward, Catherine Anne & Tiainen, Hanna (2025). Tannic acid and arginine nanocoatings for soft tissue integration of titanium dental implants. Fulltekst i vitenarkiv

Se alle arbeider i NVA