Stem cell culture and differentiation in 3-D scaffolds

In vitro co-culture of Fasciola hepatica newly excysted juveniles (NEJs) with 3D HepG2 spheroids permits novel investigation of host-parasite interactions

Fasciola hepatica, or liver fluke, causes fasciolosis in humans and livestock. Following ingestion of vegetation contaminated with encysted parasites, metacercariae, newly excysted juveniles (NEJ) excyst in the small intestine and cross the intestinal wall. After penetrating the liver, the parasite begins an intra-parenchymal migratory and feeding phase that not only drives their rapid growth and development but also causes extensive haemorrhaging and immune pathology. Studies on infection are hindered by the difficulty in accessing these microscopic juvenile parasites in vivo. Thus, a simple and scalable in vitro culture system for parasite development is needed. Here, we find that two-dimensional (2D) culture systems using cell monolayers support NEJ growth to a limited extent. By contrast, co-culture of F. hepatica NEJ with HepG2-derived 3D spheroids, or "mini-livers," that more closely mimic the physiology and microenvironment of in vivo liver tissue, promoted NEJ survival, growth, and development. NEJ grazed on the peripheral cells of the spheroids, and they released temporally regulated digestive cysteine proteases, FhCL3, and FhCL1/2, similar to in vivo parasites. The 3D co-culture induced development of the NEJ gut and body musculature, and stimulated the tegument to elaborate spines and a variety of surface sensory/tango/chemoreceptor papillae (termed S1, S2, and S3); these were especially pronounced around the oral and ventral suckers that sense host chemical cues and secure the parasite in tissue. HepG2 3D spheroid/parasite co-culture methodologies should accelerate investigations into the understanding of F. hepatica NEJ developmental biology and studies on host-parasite interactions, and streamline the search for new anti-parasite interventions.

Leaf vein scaffolds for three-dimensional culture of PDLSCs-derived Muse cells

Periodontal disease, a significant global health burden, has encountered limited success with current therapeutic strategies to achieve full tissue regeneration. The emergence of Multilineage Differentiation and Stress-Enduring (Muse) cells presents a promising avenue for periodontal tissue regeneration. This study introduced a novel three-dimensional (3D) culture system utilizing Magnolia leaf vein scaffolds, characterized for their biocompatibility and evaluated for their impact on Muse cells' proliferation, adhesion, osteogenic differentiation, and exosome secretion. The isolation of Muse cells from Periodontal Ligament Stem Cells (PDLSCs) was successfully accomplished, with excellent compatibility observed with the plant-derived scaffolds. Notably, the 3D culture substantially upregulated osteogenic markers and promoted the formation of mineralized nodules, signifying enhanced osteogenic potential. Additionally, Muse cells in 3D culture exhibited a significant increase in exosome secretion, which were more effective in stimulating PDLSCs proliferation. The study concluded that plant leaf vein scaffolds provide a sustainable and effective platform for 3D stem cell culture, with the potential to significantly enhance the therapeutic efficacy of Muse cells in periodontal tissue engineering.

Three-Dimensional Trilineage Differentiation Conditions for Human Induced Pluripotent Stem Cells

Human induced pluripotent stem cells (hiPSCs) hold great potential for regenerative medicine. However, optimizing their differentiation into specific lineages within three-dimensional (3D) scaffold-based culture systems that mimic in vivo environments remains challenging. This study examined the trilineage differentiation of hiPSCs under various 3D conditions using synthetic peptide hydrogel matrices with and without embryoid body (EB) medium induction. hiPSC 3D colonies (spheroids), naturally formed from single cells or small clusters in 3D culture, were used for differentiation into the three germ lineages. Differentiated spheroids exhibited distinct morphological characteristics and significantly increased expression of key lineage-specific markers-FOXA2 (endoderm), Brachyury (mesoderm), and PAX6 (ectoderm)-compared to undifferentiated controls. Marker expression varied depending on the 3D culture conditions. Differentiation efficiency improved significantly, increasing from 16% to 71% for endoderm, 61% to 80% for mesoderm, and 35% to 48% for ectoderm, by selecting the appropriate 3D matrix and applying EB induction. Comprehensive data analysis from RT-qPCR, immunocytochemistry staining, and flow cytometry confirmed that the Synthegel Spheroid (SGS) is a viable 3D matrix for evaluating all three germ lineages using a commercial trilineage differentiation kit. While EB induction is essential for endodermal differentiation, it is not required for mesodermal and ectodermal lineages. These findings are valuable not only for screening initial differentiation potential at the lineage level but also for optimizing 3D differentiation protocols for deriving somatic cells from hiPSCs.