3D Cell Cultures: Evolution of an Ancient Tool for New Applications

ZSCAN21 mediates the pathogenic transcriptional induction of α-synuclein in cellular and animal models of Parkinson's disease

The expression level of α-synuclein is thought to play a crucial role in the pathogenesis of Parkinson's disease. However, little is known about the molecular mechanisms regulating the transcription of its gene, SNCA, particularly in the context of the disease. The transcription factor ZSCAN21 has been shown to act on SNCA, but whether ZSCAN21 is actually involved in the induction of SNCA transcription in Parkinson's disease is unknown. To address this question, we used the MPTP mouse model and LUHMES-derived dopaminergic neuronal spheroids, subjected to Parkinson's disease-related neurotoxins and mutations. We show that MPP+-treated spheroids recapitulate the main features of α-synuclein pathology and that MPP+-triggered transcriptional induction of SNCA is associated with ZSCAN21 stabilisation. Importantly, knock-down of ZSCAN21 prevents both the MPP+-triggered increase in α-synuclein mRNA and pre-mRNA levels in LUHMES-derived spheroids and the death of dopaminergic neurons in the substantia nigra of MPTP-treated mice. These effects are recapitulated by knockdown of TRIM17, a ZSCAN21 stabiliser which prevents its ubiquitination and degradation mediated by TRIM41. Moreover, reducing the interaction between ZSCAN21 and TRIM41, either by inserting Parkinson's disease-associated mutations into the TRIM41 gene or by preventing SUMOylation of ZSCAN21, results in both stabilisation of ZSCAN21 and induction of SNCA. Taken together, our data strongly suggest that ZSCAN21 is a crucial transcription factor for pathogenic α-synuclein expression and neurodegeneration in Parkinson's disease, pointing to its regulators, TRIM17 and TRIM41, as original therapeutic targets for a neuroprotective treatment of Parkinson's disease.

Sequentially assembled co-delivery nanoplatform of SIRT1 protein and SOX9-expressing plasmid for multipronged therapy of intervertebral disc degeneration

Nucleus pulposus cells (NPCs) undergo metabolic disorders and matrix pathological remodeling under the influence of various adverse factors during intervertebral disc degeneration (IVDD), whereas post-translational modifications (PTMs) can confer cells with the capacity to respond quickly and adapt to complex environmental changes. Here, SIRT1 protein, a key regulator within PTMs framework, was applied against the hostile degenerative microenvironment. Then, it was sequentially assembled with SOX9-expressing plasmid, an essential transcription factor to promote extracellular matrix (ECM) biosynthesis, onto a phenylboronic acid-functionalized G5-dendrimer to construct a multifunctional nanoplatform for IVDD therapy. In vitro, the nanoplatforms showed antioxidant capacity, and the ability to restore mitochondrial homeostasis and normal ECM metabolism, as well as to maintain cellular phenotypes. RNA sequencing suggested that inhibition of the Nod-like receptor signaling might be the mechanism behind their therapeutic effects. The nanoplatforms were then wrapped in a designed dynamic hydrogel, not only prolonging the retention time of the loaded cargoes, but also well maintaining the disc structure, height, and water content in vivo. Overall, this study presents a convenient assembled strategy to inhibit the multiple adverse factors, and hold promise for the IVDD treatment.

Cannabinol improves exemestane efficacy in estrogen receptor-positive breast cancer models: a comparative study with cannabidiol

Cannabinoids have been used as anti-emetic agents in cancer. However, multiple studies suggest that cannabinoids present important anti-tumor actions as well. Estrogen receptor-positive (ER+) breast cancer is the most diagnosed breast cancer subtype, and despite the success of endocrine therapy, endocrine resistance development is a major challenge, demanding the discovery or implementation of alternative therapeutic approaches. In line with this, and following our previous work, the benefits of combining the aromatase inhibitors (AIs) used in the clinic, anastrozole (Ana), letrozole (Let), and exemestane (Exe), with cannabinol (CBN) were evaluated. Experiments were performed in MCF-7aro cells and spheroids to assess activity against specific molecular targets and underlying mechanisms of action. Among the three AIs studied, only the combination of CBN with Exe induced a significant beneficial impact on viability and growth of ER+ breast cancer cells and spheroids. Our results demonstrated that this combination was more effective than Exe in preventing the expression of aromatase and in modulating ERα and androgen receptor (AR) activity. In fact, the results revealed that CBN can prevent de novo synthesis of aromatase, surpass Exe's weak estrogen-like effect, and avoid the unfavorable overexpression of AR. By comparing these two therapeutic strategies, as well as the previously studied combination of Exe plus cannabidiol (CBD), differential transcriptome profiles were detected, which may help to better understand the mechanism of action of cannabinoids and disclose their full potential in breast cancer treatment. In conclusion, this study strengthens the hypothesis that cannabinoids are important anti-cancer agents with attractive co-adjuvant properties.

Quercetin-calcium hydroxide scaffolds modulate dental pulp stem cell response in vitro under a simulated inflammatory environment

AIM

Tissue engineering can be applied to dentine regeneration, stimulating tissue repair by promoting mesenchymal cell migration and differentiation into odontoblast-like cells while modulating inflammation. This study aimed to investigate the effect of quercetin (QU) and calcium hydroxide (CH) incorporated into polycaprolactone (PCL)/polyethylene oxide (PEO) scaffolds on the differentiation of dental pulp stem cells (DPSCs) in a simulated inflammatory environment in vitro.

METHODOLOGY

Dental pulp stem cells (DPSCs) were cultured and treated with different concentrations of quercetin (QU) to assess cell viability, mineralized matrix production and responses under inflammatory stimuli. Reactive oxygen and nitrogen species, as well as TNF-α synthesis, were quantified using fluorescence and ELISA methods. Scaffolds of PCL/PEO with calcium hydroxide and QU were fabricated via electrospinning, characterized and analysed for cell adhesion, viability, inflammatory and mineralisation-related genes in an artificial pulp chamber model. Statistical analysis was performed using anova, Kruskal-Wallis and confidence intervals with a significance level of 5%.

RESULTS

Polycaprolactone/polyethylene oxide scaffolds incorporated with CH and QU showed cytocompatibility and support for DPSC differentiation at concentrations of up to 5 M diluted in the culture medium. After 14 days of treatment, the scaffolds upregulated ALPL gene expression under the inflammatory stimulus, with no differences between the control group and the nonincorporated scaffold. The expression of osteocalcin (OCN) and dentine sialophosphoprotein (DSPP) genes was significantly upregulated for the scaffold-treated group when stimulated with LPS.

CONCLUSIONS

Incorporating QU and CH into PCL/PEO scaffolds modulated the inflammatory-related response and upregulated mineralisation-related genes of LPS-challenged dental pulp stem cells.

Decellularized apple hypanthium as a plant-based biomaterial for cartilage regeneration in vitro: a comparative study of progenitor cell types and environmental conditions

BACKGROUND

Decellularized plant tissues have been shown to enhance the integration and proliferation of human cells, demonstrating biocompatibility. These tissues are now being considered as valuable biomaterials for tissue engineering due to their diverse architectures and favorable cytocompatibility. In this study, we assessed decellularized apple hypanthium as a potential biomaterial for generating cartilage-like structures, utilizing four different progenitor cell types and varying environmental conditions in vitro.

RESULTS

Cell viability assays indicated integration and cell proliferation. Histological staining and gene expression analyses confirmed the synthesis and deposition of a cartilaginous extracellular matrix. Notably, hypoxia had varying effects on chondrogenesis based on the cell type. Among the progenitor cells evaluated, those derived from auricular perichondrium were particularly promising, as they differentiated into chondrocytes without requiring a low-oxygen environment. Additionally, our findings demonstrated that apple-derived biomaterials outperformed microencapsulation in alginate beads in promoting chondrogenesis.

CONCLUSION

These results highlight the potential of plant-based biomaterials for the development of implantable devices for cartilage regeneration and suggest broader applications in tissue engineering and future clinical endeavors.

Imaging 3D cell cultures with optical microscopy

Three-dimensional (3D) cell cultures have gained popularity in recent years due to their ability to represent complex tissues or organs more faithfully than conventional two-dimensional (2D) cell culture. This article reviews the application of both 2D and 3D microscopy approaches for monitoring and studying 3D cell cultures. We first summarize the most popular optical microscopy methods that have been used with 3D cell cultures. We then discuss the general advantages and disadvantages of various microscopy techniques for several broad categories of investigation involving 3D cell cultures. Finally, we provide perspectives on key areas of technical need in which there are clear opportunities for innovation. Our goal is to guide microscope engineers and biomedical end users toward optimal imaging methods for specific investigational scenarios and to identify use cases in which additional innovations in high-resolution imaging could be helpful.

Advancing humanized 3D tumor modeling using an open access xeno-free medium

Despite limitations like poor mimicry of the human cell microenvironment, contamination risks, and batch-to-batch variation, cell culture media with animal-derived components such as fetal bovine serum (FBS) have been used in vitro for decades. Moreover, a few reports have used animal-product-free media in advanced high throughput three-dimensional (3D) models that closely mimic in vivo conditions. To address these challenges, we combined a high throughput 3D model with an open access, FBS-free chemically-defined medium, Oredsson Universal Replacement (OUR) medium, to create a more realistic 3D in vitro drug screening system. To reach this goal, we report the gradual adaptation procedure of three cell lines: human HeLa cervical cancer cells, human MCF-7 breast cancer cells, and cancer-associated fibroblasts (CAFs) from FBS-supplemented medium to OUR medium, while closely monitoring cell attachment, proliferation, and morphology. Our data based on cell morphology studies with phase contrast and real-time live imaging demonstrates a successful adaptation of cells to proliferate in OUR medium showing sustained growth kinetics and maintaining population doubling time. The morphological analysis demonstrates that HeLa and MCF-7 cells displayed altered cell morphology, with a more spread-out cytoplasm and significantly lower circularity index, while CAFs remained unaffected when grown in OUR medium. 3D fiber scaffolds facilitated efficient cell distribution and ingrowth when grown in OUR medium, where cells expand and infiltrate into the depths of 3D scaffolds. Drug toxicity evaluation of the widely used anti-cancer drug paclitaxel (PTX) revealed that cells grown in 3D cultures with OUR medium showed significantly lower sensitivity to PTX, which was consistent with the FBS-supplemented medium. We believe this study opens the way and encourages the scientific community to use animal product-free cell culture medium formulations for research and toxicity testing.

Multiparametric physicochemical analysis of a type 1 collagen 3D cell culture model using light and electron microscopy and mass spectrometry imaging

Three-dimensional cell culture systems underpin cell-based technologies ranging from tissue scaffolds for regenerative medicine to tumor models and organoids for drug screening. However, to realise the full potential of these technologies requires analytical methods able to capture the diverse information needed to characterize constituent cells, scaffold components and the extracellular milieu. Here we describe a multimodal imaging workflow which combines fluorescence, vibrational and second harmonic generation microscopy with secondary ion mass spectrometry imaging and transmission electron microscopy to analyse the morphological, chemical and ultrastructural properties of cell-seeded scaffolds. Using cell nuclei as landmarks we register fluorescence with label-free optical microscopy images and high mass resolution with high spatial resolution secondary ion mass spectrometry images, with an accuracy comparable to the intrinsic spatial resolution of the techniques. We apply these methods to investigate relationships between cell distribution, cytoskeletal morphology, scaffold fiber organisation and biomolecular composition in type I collagen scaffolds seeded with human dermal fibroblasts.

ImmunoMet Oncogenesis: A New Concept to Understand the Molecular Drivers of Cancer

The appearance of cancer progresses through a multistep process that includes genetic, epigenetic, mutational, inflammatory and metabolic disturbances to signaling pathways within an organ. The combined influence of these changes will dictate the growth properties of the cells; the direction of further malignancy depends on the severity of these "disturbances". The molecular mechanisms driving abnormal inflammation and metabolism are beginning to be identified and, in some cases, are quite prominent in pre-condition states of cancer and are significant drivers of the malignant phenotype. As such, utilizing signaling pathways linked to inflammation and metabolism as biomarkers of cancer is an emerging method and includes pathways beyond those well characterized to drive metabolism or inflammation. In this review, we will discuss several emerging elements influencing proliferation, inflammation and metabolism that may play a part as drivers of the cancer phenotype. These include AMPK and leptin (linked to metabolism), NOD2/RIPK2, TAK1 (linked to inflammation), lactate and pyruvate transporters (monocarboxylate transporter [MCT], linked to mitochondrial biogenesis and metabolism) and RASSF1A (linked to proliferation, cell death, cell cycle control, inflammation and epigenetics). We speculate that the aforementioned elements are important drivers of carcinogenesis that should be collectively referenced as being involved in "ImmunoMET Oncogenesis", a new tripartite description of the role of elements in driving cancer. This term would suggest that for a better understanding of cancer, we need to understand how proliferation, inflammation and metabolic pathways are impacted and how they influence classical drivers of malignant transformation in order to drive ImmunoMET oncogenesis and the malignant state.

The Evolution of Anticancer 3D In Vitro Models: The Potential Role of Machine Learning and AI in the Next Generation of Animal-Free Experiments

The development of anticancer therapies has increasingly relied on advanced 3D in vitro models, which more accurately mimic the tumor microenvironment compared to traditional 2D cultures. This review describes the evolution of these 3D models, highlighting significant advancements and their impact on cancer research. We discuss the integration of machine learning (ML) and artificial intelligence (AI) in enhancing the predictive power and efficiency of these models, potentially reducing the dependence on animal testing. ML and AI offer innovative approaches for analyzing complex data, optimizing experimental conditions, and predicting therapeutic outcomes with higher accuracy. By leveraging these technologies, the next generation of 3D in vitro models could revolutionize anticancer drug development, offering effective alternatives to animal experiments.

Development and characterization of a double-crested cormorant hepatic cell line, DCH22, for chemical screening

There are currently no available cell lines for the ecologically relevant colonial waterbird species, the double-crested cormorant (DCCO). DCCOs are high trophic level aquatic birds that are used for routine contaminant monitoring programs in the Laurentian Great Lakes and marine coasts of Canada. Developing a DCCO cell line for in vitro toxicological screening will ideally provide improved understanding of the effects of environmental chemicals given the large differences in sensitivity between laboratory and wild avian species. In this study, an immortalized DCCO hepatic cell line, DCH22, was established from the liver of a day 22 female embryo as a potential alternative to primary DCCO embryonic hepatocytes (DCEH) for chemical screening. DCH22 cells were cultured for over a year and have hepatocyte-like morphology. Exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB-126), benzo-a-pyrene, ß-napthoflavone and phenacetin induced CYP1A activity and mRNA expression in DCH22 3D spheroids. Induction of CYP3A activity and mRNA expression was observed following exposure to hexabromocyclododecane (HBCD), tris(1,3-dichloroisopropyl)phosphate, carbamazepine, and metyrapone. The phase II metabolism gene, UGT1A1, was upregulated following HBCD exposure and DCH22 spheroids expressed vitellogenin protein after exposure to 17α-ethinylestradiol. Based on these data, the novel DCH22 cell line, cultured as 3D spheroids, has potential use as an alternative to DCEH for chemical screening and will permit the evaluation of avian species differences in sensitivity from an in vitro screening perspective.

CellStudio: a Modular, Tunable and Accessible Platform for Analysis of Growth Factors Secretions in Cell Cultures

Traditional cell culture methods face significant limitations in monitoring cell secretions with spatial and temporal precision. Advanced microsystems incorporating biosensors have been developed to address these challenges, but they tend to lack versatility, and their complexity, along with the requirement for specialized equipment, limits their broader adoption. CellStudio offers an innovative, user-friendly solution that exploits Printing and Vacuum Lithography combined with bead-based assays to create modular and tunable cell patterns surrounded by biosensors. This platform allows for high-resolution, spatially resolved analysis of secreted proteins, such as VEGF and FGF-2, while being easily implementable in standard laboratory settings. CellStudio's design is compatible with conventional laboratory equipment, facilitating its integration into existing workflows without the need for extensive training or specialized tools. Validation experiments using mesenchymal stem cells and HeLa cells demonstrated that CellStudio can detect small secretion levels from small cell clusters with high sensitivity and analyze diffusion profiles, remarking the possibilities for studying cell behavior. By offering a standardized, cost-effective approach to detailed cellular analysis, CellStudio significantly enhances the capabilities of traditional cell culture techniques with broad applications across biological and biomedical research.

3D bioprinting of prefabricated artificial skin with multicomponent hydrogel for skin and hair follicle regeneration

Background: The timely management of large-scale wounds and the regeneration of skin appendages constitute major clinical issues. The production of high-precision and customizable artificial skin via 3D bioprinting offers a feasible means to surmount the predicament, within which the selection of bioactive materials and seed cells is critical. This study is aimed at employing skin stem cells and multicomponent hydrogels to prefabricate artificial skin through 3D bioprinting, which enables the regeneration of skin and its appendages. Methods and Results: We employed gelatin methacrylate (GelMA) and hyaluronic acid methacrylate (HAMA) as bioactive materials, in conjunction with epidermal stem cells (Epi-SCs) and skin-derived precursors (SKPs), to fabricate artificial skin utilizing 3D bioprinting. The photosensitive multicomponent hydrogel, comprising 5% GelMA and 0.5% HAMA, demonstrated excellent printability, suitable solubility and swelling rates, as well as stable mechanical properties. Moreover, this hydrogel exhibited exceptional biocompatibility, effectively facilitating the proliferation of SKPs while maintaining the cellular characteristics of both SKPs and Epi-SCs. The transplantation of this artificial skin into cutaneous wounds in nude mice led to complete wound healing and functional tissue regeneration. The regenerated tissue comprised epidermis, dermis, hair follicles, blood vessels, and sebaceous glands, closely resembling native skin. Remarkably, the artificial skin demonstrated sustained tissue regeneration capacity even after 12 h of in vitro culture, facilitating comprehensive functional skin regeneration. Conclusions: Our research presented a skin repair strategy for prefabricated cell-loaded artificial skin, thereby successfully facilitating the regeneration of the epidermis, dermis, hair follicles, blood vessels, and sebaceous glands within the wound.

Isolation, identification, and challenges of extracellular vesicles: emerging players in clinical applications

Extracellular vesicles (EVs) serve as critical mediators of intercellular communication, encompassing exosomes, microvesicles, and apoptotic vesicles that play significant roles in diverse physiological and pathological contexts. Numerous studies have demonstrated that EVs derived from mesenchymal stem cells (MSC-EVs) play a pivotal role in facilitating tissue and organ repair, alleviating inflammation and apoptosis, enhancing the proliferation of endogenous stem cells within tissues and organs, and modulating immune function-these functions have been extensively utilized in clinical applications. The precise classification, isolation, and identification of MSC-EVs are essential for their clinical applications. This article provides a comprehensive overview of the biological properties of EVs, emphasizing both their advantages and limitations in isolation and identification methodologies. Additionally, we summarize the protein markers associated with MSC-EVs, emphasizing their significance in the treatment of various diseases. Finally, this article addresses the current challenges and dilemmas in developing clinical applications for MSC-EVs, aiming to offer valuable insights for future research.

A DIY Bioreactor for in Situ Metabolic Tracking in 3D Cell Models via Hyperpolarized 13C NMR Spectroscopy

Nuclear magnetic resonance (NMR) spectroscopy is a valuable diagnostic tool limited by low sensitivity due to low nuclear spin polarization. Hyperpolarization techniques, such as dissolution dynamic nuclear polarization, significantly enhance sensitivity, enabling real-time tracking of cellular metabolism. However, traditional high-field NMR systems and bioreactor platforms pose challenges, including the need for specialized equipment and fixed sample volumes. This study introduces a scalable, 3D-printed bioreactor platform compatible with low-field NMR spectrometers, designed to accommodate bioengineered 3D cell models. The bioreactor is fabricated using biocompatible materials and features a microfluidic system for media recirculation, ensuring optimal culture conditions during NMR acquisition and cell maintenance. We characterized the NMR compatibility of the bioreactor components and confirmed minimal signal distortion. The bioreactor's efficacy was validated using HeLa and HepG2 cells, demonstrating prolonged cell viability and enhanced metabolic activity in 3D cultures compared to 2D cultures. Hyperpolarized [1-13C] pyruvate experiments revealed distinct metabolic profiles for the two cell types, highlighting the bioreactor's ability to discern metabolic profiles among samples. Our results indicate that the bioreactor platform supports the maintenance and analysis of 3D cell models in NMR studies, offering a versatile and accessible tool for metabolic and biochemical research in tissue engineering. This platform bridges the gap between advanced cellular models and NMR spectroscopy, providing a robust framework for future applications in nonspecialized laboratories. The design files for the 3D printed components are shared within the text for easy download and customization, promoting their use and adaptation for further applications.

Transcriptomic characterization of 2D and 3D human induced pluripotent stem cell-based in vitro models as New Approach Methodologies for developmental neurotoxicity testing

The safety and developmental neurotoxicity (DNT) potential of chemicals remain critically understudied due to limitations of current in vivo testing guidelines, which are low throughput, resource-intensive, and hindered by species differences that limit their relevance to human health. To address these issues, robust New Approach Methodologies (NAMs) using deeply characterized cell models are essential. This study presents the comprehensive transcriptomic characterization of two advanced human-induced pluripotent stem cell (hiPSC)-derived models: a 2D adherent and a 3D neurosphere model of human neural progenitor cells (hiNPCs) differentiated up to 21 days. Using high-throughput RNA sequencing, we compared gene expression profiles of 2D and 3D models at three developmental stages (3, 14, and 21 days of differentiation). Both models exhibit maturation towards post-mitotic neurons, with the 3D model maturing faster and showing a higher prevalence of GABAergic neurons, while the 2D model is enriched with glutamatergic neurons. Both models demonstrate broad applicability domains, including excitatory and inhibitory neurons, astrocytes, and key endocrine and especially the understudied cholinergic receptors. Comparison with human fetal brain samples confirms their physiological relevance. This study provides novel in-depth applicability insights into the temporal and dimensional aspects of hiPSC-derived neural models for DNT testing. The complementary use of these two models is highlighted: the 2D model excels in synaptogenesis assessment, while the 3D model is particularly suited for neural network formation as observed as well in previous functional studies with these models. This research marks a significant advancement in developing human-relevant, high-throughput DNT assays for regulatory purposes.

Micronuclei as genotoxicity endpoint applied in the co-culture of two mammalian cell lines

There has been a shift from traditional animal models towards alternative methods. While 2D cell culture has a decade long tradition, more advances methods like 3D cultures, organoids, and co-culture techniques, which better mimic in vivo conditions, are not yet well established in every research area. Genotoxicity assessment is an integral part of toxicological testing or regulatory approval of pharmaceuticals and chemicals. The micronucleus assay is now a standard method in this context. In this systematic literature review, we aim to describe the state of the art of the application of co-cultures of two mammalian cell lines for micronucleus assessment. We summarized the cell types used, methods for co-culture, disease models and agents, as well as the application of additional genotoxicity endpoints and viability tests. Airway system cells were the most frequent, followed by macrophage-like cells, liver cells, and various others. Co-culture techniques involve either direct physical contact or separation by porous membranes. Within a limited number of investigations using other genotoxicity assays like the comet and γH2AX assays in parallel, the micronucleus assay performed well. Overall, the micronucleus test demonstrating its suitability in disease models and for a more complex substance testing beyond simple 2D cultures, encouraging a more widespread use in co-culture systems in the future.

Extracellular vesicles: From large-scale production and engineering to clinical applications

Extracellular vesicles (EVs) have emerged as a promising strategy for treating a wide spectrum of pathologies, as they can deliver their cargo to recipient cells and regulate the signaling pathway of these cells to modulate their fate. Despite the great potential of EVs in clinical applications, their low yield and the challenges of cargo loading remain significant obstacles, hindering their transition from experimental research to clinical practice. Therefore, promoting EV release and enhancing EV cargo-loading are promising fields with substantial research potential and broad application prospects. In this review, we summarize the clinical applications of EVs, the methods and technologies for their large-scale production, engineering, and modification, as well as the challenges that must be addressed during their development. We also discuss the future perspectives of this exciting field of research to facilitate its transformation from bench to clinical reality.

A Brief History of Cell Culture: From Harrison to Organs-on-a-Chip

This comprehensive overview of the historical milestones in cell culture underscores key breakthroughs that have shaped the field over time. It begins with Wilhelm Roux's seminal experiments in the 1880s, followed by the pioneering efforts of Ross Granville Harrison, who initiated groundbreaking experiments that fundamentally shaped the landscape of cell culture in the early 20th century. Carrel's influential contributions, notably the immortalization of chicken heart cells, have marked a significant advancement in cell culture techniques. Subsequently, Johannes Holtfreter, Aron Moscona, and Joseph Leighton introduced methodological innovations in three-dimensional (3D) cell culture, initiated by Alexis Carrel, laying the groundwork for future consolidation and expansion of the use of 3D cell culture in different areas of biomedical sciences. The advent of induced pluripotent stem cells by Takahashi and Yamanaka in 2006 was revolutionary, enabling the reprogramming of differentiated cells into a pluripotent state. Since then, recent innovations have included spheroids, organoids, and organ-on-a-chip technologies, aiming to mimic the structure and function of tissues and organs in vitro, pushing the boundaries of biological modeling and disease understanding. In this review, we overview the history of cell culture shedding light on the main discoveries, pitfalls and hurdles that were overcome during the transition from 2D to 3D cell culture techniques. Finally, we discussed the future directions for cell culture research that may accelerate the development of more effective and personalized treatments.

Advances in, and prospects of, 3D preclinical models for skin drug discovery

The skin has an important role in regulating homeostasis and protecting the body from endogenous and exogenous microenvironments. Although 3D models for drug discovery have been extensively studied, there is a growing demand for more advanced 3D skin models to enhance skin research. The use of these advanced skin models holds promise across domains such as cosmetics, skin disease treatments, and toxicity testing of new therapeutics. Recent advances include the development of skin-on-a-chip, spheroids, reconstructed skin, organoids, and computational approaches, including quantitative structure-activity relationship (QSAR) and quantitative structure-property relationship (QSPR) research. These innovations are bridging the gap between traditional 2D and advanced 3D models, moving progress from research to clinical applications. In this review, we highlight in vitro and computational skin models with advanced drug discovery for skin-related applications.

A multimodal in vitro approach to assess the safety of oral care products using 2D and 3D cellular models

Introduction

Periodontitis, affecting approximately 3.9 billion individuals globally, significantly impacts quality of life and has raised interest in its potential systemic effects. Sodium perborate, a common component in oral care products for biofilm control, is widely used, though concerns about its safety persist. This study aimed to evaluate the in vitro toxicity of six commercial oral care products and varying concentrations of sodium perborate, utilizing human gingival fibroblasts (HGF) and keratinocytes (HaCat) as cell models.

Methods

Experiments were performed in both 2D monolayer and 3D cultures using MTT and electrical impedance assays, adhering to the manufacturer's recommended exposure time of 30-60 s for product testing. For the reconstructed epidermis model, a prolonged exposure time of 42 min was applied, following the Organization for Economic Cooperation and Development (OECD) Test Guideline 439.

Results

Results indicated that all products and sodium perborate at 1 mg/mL were cytotoxic in monolayer cultures. However, at concentrations relevant to commercial formulations (0.06 mg/mL sodium perborate), no significant toxicity was observed. In contrast, the 3D culture models, including spheroids and reconstructed epidermis, exhibited minimal to no cytotoxic effects for the commercial products, with sodium perborate showing no significant toxicity below 0.1 mg/mL. The reconstructed epidermis model, used as surrogate for oral mucosa, further confirmed that the products were non-irritating, in compliance with OECD TG 439 standards.

Discussion

This study highlights the importance of considering exposure time, dosage, and cellular model when assessing the safety of oral care products. While 2D models are useful for preliminary screenings, 3D models provide a more physiologically relevant assessment, emphasizing the need for robust testing protocols to ensure product safety.

Toolbox for creating three-dimensional liver models

Research within the hepato-biliary system and hepatic function is currently experiencing heightened interest, this is due to the high frequency of relapse rates observed in chronic conditions, as well as the imperative for the development of innovative therapeutic strategies to address both inherited and acquired diseases within this domain. The most commonly used sources for studying hepatocytes include primary human hepatocytes, human hepatic cancer cell lines, and hepatic-like cells derived from induced pluripotent stem cells. However, a significant challenge in primary hepatic cell culture is the rapid decline in their phenotypic characteristics, dedifferentiation and short cultivation time. This limitation creates various problems, including the inability to maintain long-term cell cultures, which can lead to failed experiments in drug development and the creation of relevant disease models for researchers' purposes. To address these issues, the creation of a powerful 3D cell model could play a pivotal role as a personalized disease model and help reduce the use of animal models during certain stages of research. Such a cell model could be used for disease modelling, genome editing, and drug discovery purposes. This review provides an overview of the main methods of 3D-culturing liver cells, including a discussion of their characteristics, advantages, and disadvantages.

Bone Spheroid Development Under Flow Conditions with Mesenchymal Stem Cells and Human Umbilical Vein Endothelial Cells in a 3D Porous Hydrogel Supplemented with Hydroxyapatite

Understanding the niche interactions between blood and bone through the in vitro co-culture of osteo-competent cells and endothelial cells is a key factor in unraveling therapeutic potentials in bone regeneration. This can be additionally supported by employing numerical simulation techniques to assess local physical factors, such as oxygen concentration, and mechanical stimuli, such as shear stress, that can mediate cellular communication. In this study, we developed a Mesenchymal Stem Cell line (MSC) and a Human Umbilical Vein Endothelial Cell line (HUVEC), which were co-cultured under flow conditions in a three-dimensional, porous, natural pullulan/dextran scaffold that was supplemented with hydroxyapatite crystals that allowed for the spontaneous formation of spheroids. After 2 weeks, their viability was higher under the dynamic conditions (>94%) than the static conditions (<75%), with dead cells central in the spheroids. Mineralization and collagen IV production increased under the dynamic conditions, correlating with osteogenesis and vasculogenesis. The endothelial cells clustered at the spheroidal core by day 7. Proliferation doubled in the dynamic conditions, especially at the scaffold peripheries. Lattice Boltzmann simulations showed negligible wall shear stress in the hydrogel pores but highlighted highly oxygenated zones coinciding with cell proliferation. A strong oxygen gradient likely influenced endothelial migration and cell distribution. Hypoxia was minimal, explaining high viability and spheroid maturation in the dynamic conditions.

Establishment of human pluripotent stem cell-derived cortical neurosphere model to study pathomechanisms and chemical toxicity in Kleefstra syndrome

In the present study, we aimed to establish and characterize a mature cortical spheroid model system for Kleefstra syndrome (KS) using patient-derived iPSC. We identified key differences in the growth behavior of KS spheroids determined by reduced proliferation marked by low Ki67 and high E-cadherin expression. Conversely, in the spheroid-based neurite outgrowth assay KS outperformed the control neurite outgrowth due to higher BDNF expression. KS spheroids were highly enriched in VGLUT1/2-expressing glutamatergic and ChAT-expressing cholinergic neurons, while TH-positive catecholamine neurons were significantly underrepresented. Furthermore, high NMDAR1 expression was also detected in the KS spheroid, similarly to other patients-derived neuronal cultures, denoting high NMDAR1 expression as a general, KS-specific marker. Control and KS neuronal progenitors and neurospheres were exposed to different toxicants (paraquat, rotenone, bardoxolone, and doxorubicin), and dose-response curves were assessed after acute exposure. Differentiation stage and compound-specific differences were detected with KS neurospheres being the most sensitive to paraquat. Altogether this study describes a robust 3D model system expressing the disease-specific markers and recapitulating the characteristic pathophysiological traits. This platform is suitable for testing developing brain-adverse environmental effects interactions, drug development, and screening towards individual therapeutic strategies.

Reversible chemoresistance of pancreatic cancer grown as spheroids

Better in vitro models are needed to identify active drugs to treat pancreatic adenocarcinoma (PAC) patients. We used 3D hanging drop cultures to produce spheroids from five PAC cell lines and tested nine FDA-approved drugs in clinical use. All PAC cell lines in 2D culture were sensitive to three drugs (gemcitabine, docetaxel and nab-paclitaxel), however most PAC (4/5) 3D spheroids acquired profound chemoresistance even at 10 µM. In contrast, spheroids retained sensitivity to the investigational drug triptolide, which induced apoptosis. The acquired chemoresistance was also transiently retained when cells were placed back into 2D culture and six genes potentially associated with chemoresistance were identified by microarray and confirmed using quantitative RT-PCR. We demonstrate the additive effect of gemcitabine and erlotinib, from the 12 different combinations of nine drugs tested. This comprehensive study shows spheroids as a useful multicellular model of PAC for drug screening and elucidating the mechanism of chemoresistance.

3D model for human glia conversion into subtype-specific neurons, including dopamine neurons

Two-dimensional neuronal cultures have a limited ability to recapitulate the in vivo environment of the brain. Here, we introduce a three-dimensional in vitro model for human glia-to-neuron conversion, surpassing the spatial and temporal constrains of two-dimensional cultures. Focused on direct conversion to induced dopamine neurons (iDANs) relevant to Parkinson disease, the model generates functionally mature iDANs in 2 weeks and allows long-term survival. As proof of concept, we use single-nucleus RNA sequencing and molecular lineage tracing during iDAN generation and find that all glial subtypes generate neurons and that conversion relies on the coordinated expression of three neural conversion factors. We also show the formation of mature and functional iDANs over time. The model facilitates molecular investigations of the conversion process to enhance understanding of conversion outcomes and offers a system for in vitro reprogramming studies aimed at advancing alternative therapeutic strategies in the diseased brain.

Tumoroids, a valid preclinical screening platform for monitoring cancer angiogenesis

In recent years, biologists and clinicians have witnessed prominent advances in in vitro 3D culture techniques related to biomimetic human/animal tissue analogs. Numerous data have confirmed that unicellular and multicellular (tumoroids) tumor spheroids with dense native cells in certain matrices are sensitive and valid analytical tools for drug screening, cancer cell dynamic growth, behavior, etc. in laboratory settings. Angiogenesis/vascularization is a very critical biological phenomenon to support oxygen and nutrients to tumor cells within the deep layer of solid masses. It has been shown that endothelial cell (EC)-incorporated or -free spheroid/tumoroid systems provide a relatively reliable biological platform for monitoring the formation of nascent blood vessels in micron/micrometer scales. Besides, the paracrine angiogenic activity of cells within the spheroid/tumoroid systems can be monitored after being treated with different therapeutic approaches. Here, we aimed to collect recent advances and findings related to the monitoring of cancer angiogenesis using unicellular and multicellular tumor spheroids. Vascularized spheroids/tumoroids can help us in the elucidation of mechanisms related to cancer formation, development, and metastasis by monitoring the main influencing factors.

Pneumatic extrusion bioprinting-based high throughput fabrication of a melanoma 3D cell culture model for anti-cancer drug screening

The high incidence of malignant melanoma highlights the need forin vitromodels that accurately represent the tumour microenvironment, enabling developments in melanoma therapy and drug screening. Despite several advancements in 3D cell culture models, appropriate melanoma models for evaluating drug efficacy are still in high demand. The 3D pneumatic extrusion-based bioprinting technology offers numerous benefits, including the ability to achieve high-throughput capabilities. However, there is a lack of research that combines pneumatic extrusion-based bioprinting with analytical assays to enable efficient drug screening in 3D melanoma models. To address this gap, this study developed a simple and highly reproducible approach to fabricate a 3D A375 melanoma cell culture model using the pneumatic extrusion-based bioprinting technology. To optimise this method, the bioprinting parameters for producing 3D cell cultures in a 96-well plate were adjusted to improve reproducibility while maintaining the desired droplet size and a cell viability of 92.13 ± 6.02%. The cross-linking method was optimised by evaluating cell viability and proliferation of the 3D bioprinted cells in three different concentrations of calcium chloride. The lower concentration of 50 mM resulted in higher cell viability and increased cell proliferation after 9 d of incubation. The A375 cells exhibited a steadier proliferation rate in the 3D bioprinted cell cultures, and tended to aggregate into spheroids, whereas the 2D cell cultures generally formed monolayered cell sheets. In addition, we evaluated the drug responses of four different anti-cancer drugs on the A375 cells in both the 2D and 3D cell cultures. The 3D cell cultures exhibited higher levels of drug resistance in all four tested anti-cancer drugs. This method presents a simple and cost-effective method of producing and analysing 3D cell culture models that do not add additional complexity to current assays and shows considerable potential for advancing 3D cell culture models' drug efficacy evaluations.

Toward Fully Automated Personalized Orthopedic Treatments: Innovations and Interdisciplinary Gaps

Personalized orthopedic devices are increasingly favored for their potential to enhance long-term treatment success. Despite significant advancements across various disciplines, the seamless integration and full automation of personalized orthopedic treatments remain elusive. This paper identifies key interdisciplinary gaps in integrating and automating advanced technologies for personalized orthopedic treatment. It begins by outlining the standard clinical practices in orthopedic treatments and the extent of personalization achievable. The paper then explores recent innovations in artificial intelligence, biomaterials, genomic and proteomic analyses, lab-on-a-chip, medical imaging, image-based biomechanical finite element modeling, biomimicry, 3D printing and bioprinting, and implantable sensors, emphasizing their contributions to personalized treatments. Tentative strategies or solutions are proposed to address the interdisciplinary gaps by utilizing innovative technologies. The key findings highlight the need for the non-invasive quantitative assessment of bone quality, patient-specific biocompatibility, and device designs that address individual biological and mechanical conditions. This comprehensive review underscores the transformative potential of these technologies and the importance of multidisciplinary collaboration to integrate and automate them into a cohesive, intelligent system for personalized orthopedic treatments.

Fibronectin Functionalization: A Way to Enhance Dynamic Cell Culture on Alginate/Hydroxyapatite Scaffolds

Bone defects are a global health concern; bone tissue engineering (BTE) is the most promising alternative to reduce patient morbidity and overcome the inherent drawbacks of autograft and allograft bone. Three-dimensional scaffolds are pivotal in this field due to their potential to provide structural support and mimic the natural bone microenvironment. Following an already published protocol, a 3D porous structure consisting of alginate and hydroxyapatite was prepared after a gelation step and a freezing-drying step. Despite the frequent use of alginate in tissue regeneration, the biological inertness of this polysaccharide hampers proper cell colonization and proliferation. Therefore, the purpose of this work was to enhance the biological properties by promoting the interaction and adhesion between cells and biomaterial with the use of Fibronectin. This extracellular matrix protein was physically adsorbed on the scaffold, and its presence was evaluated with environmental scanning electron microscopy (eSEM) and the Micro-Bicinchoninic Acid (μBCA) protein assay. The MG-63 cell line was used for both static and dynamic (i.e., in bioreactor) 3D cell culturing on the scaffolds. The use of the bioreactor allowed for a better exchange of nutrients and oxygen and a better removal of cell catabolites from the inner portion of the construct, mimicking the physiological environment. The functionalized scaffolds showed an improvement in cell proliferation and colonization compared to non-functionalized ones; the effect of the addition of Fibronectin was more evident in the dynamic culturing conditions, where the cells clearly adhered on the surface of functionalized scaffolds.

Lutein Modulates Cellular Functionalities and Regulates NLRP3 Inflammasome in a H2O2-Challenged Three-Dimensional Retinal Pigment Epithelium Model

Excessive hydrogen peroxide (H2O2) generated during retinal cell metabolic activity could lead to oxidative degeneration of retinal pigment epithelium (RPE) tissue, a specific pathological process implicated in various retinal diseases resulting in blindness, which can be mitigated by taking dietary antioxidants to prevent inflammation and impaired cellular dysfunction. This study tested the hypothesis that damages induced by oxidative stresses can be mitigated by lutein in a H2O2-challenged model, which was based on an ARPE-19 cell monolayer cultured on three-dimensional (3D)-printed fibrous scaffolds. Pretreating these models with lutein (0.5 μM) for 24 h can significantly lower the oxidative stress and maintain phagocytosis and barrier function. Moreover, lutein can modulate the NLRP3 inflammasome, leading to a ∼40% decrease in the pro-inflammatory cytokine (IL-1β and IL-18) levels. Collectively, this study suggests that the 3D RPE model is an effective tool to examine the capability of lutein to modulate cellular functionalities and regulate NLRP3 inflammation.

Use of iPSC-Derived Smooth Muscle Cells to Model Physiology and Pathology

The implementation of human induced pluripotent stem cell (hiPSC) models has introduced an additional tool for identifying molecular mechanisms of disease that complement animal models. Patient-derived or CRISPR/Cas9-edited induced pluripotent stem cells differentiated into smooth muscle cells (SMCs) have been leveraged to discover novel mechanisms, screen potential therapeutic strategies, and model in vivo development. The field has evolved over almost 15 years of research using hiPSC-SMCs and has made significant strides toward overcoming initial challenges such as the lineage specificity of SMC phenotypes. However, challenges both specific (eg, the lack of specific markers to thoroughly validate hiPSC-SMCs) and general (eg, a lack of transparency and consensus around methodology in the field) remain. In this review, we highlight the recent successes and remaining challenges of the hiPSC-SMC model.

Comprehensive approaches to preclinical evaluation of monoclonal antibodies and their next-generation derivatives

Biotherapeutics hold great promise for the treatment of several diseases and offer innovative possibilities for new treatments that target previously unaddressed medical needs. Despite successful transitions from preclinical to clinical stages and regulatory approval, there are instances where adverse reactions arise, resulting in product withdrawals. As a result, it is essential to conduct thorough evaluations of safety and effectiveness on an individual basis. This article explores current practices, challenges, and future approaches in conducting comprehensive preclinical assessments to ensure the safety and efficacy of biotherapeutics including monoclonal antibodies, toxin-conjugates, bispecific antibodies, single-chain antibodies, Fc-engineered antibodies, antibody mimetics, and siRNA-antibody/peptide conjugates.

Mouse vascularized adipose spheroids: an organotypic model for thermogenic adipocytes

Adipose tissues, particularly beige and brown adipose tissue, play crucial roles in energy metabolism. Brown adipose tissues' thermogenic capacity and the appearance of beige cells within white adipose tissue have spurred interest in their metabolic impact and therapeutic potential. Brown and beige fat cells, activated by environmental factors like cold exposure or by pharmacology, share metabolic mechanisms that drive non-shivering thermogenesis. Understanding these two cell types requires advanced, yet broadly applicable in vitro models that reflect the complex microenvironment and vasculature of adipose tissues. Here we present mouse vascularized adipose spheroids of the stromal vascular microenvironment from inguinal white adipose tissue, a tissue with 'beiging' capacity in mice and humans. We show that adding a scaffold improves vascular sprouting, enhances spheroid growth, and upregulates adipogenic markers, thus reflecting increased adipocyte maturity. Transcriptional profiling via RNA sequencing revealed distinct metabolic pathways upregulated in our vascularized adipose spheroids, with increased expression of genes involved in glucose metabolism, lipid metabolism, and thermogenesis. Functional assessment demonstrated increased oxygen consumption in vascularized adipose spheroids compared to classical 2D cultures, which was enhanced by β-adrenergic receptor stimulation correlating with elevated β-adrenergic receptor expression. Moreover, stimulation with the naturally occurring adipokine, FGF21, induced Ucp1 mRNA expression in the vascularized adipose spheroids. In conclusion, vascularized inguinal white adipose tissue spheroids provide a physiologically relevant platform to study how the stromal vascular microenvironment shapes adipocyte responses and influence activated thermogenesis in beige adipocytes.

Osteochondral organoids: current advances, applications, and upcoming challenges

In the realm of studying joint-related diseases, there is a continuous quest for more accurate and representative models. Recently, regenerative medicine and tissue engineering have seen a growing interest in utilizing organoids as powerful tools for studying complex biological systems in vitro. Organoids, three-dimensional structures replicating the architecture and function of organs, provide a unique platform for investigating disease mechanisms, drug responses, and tissue regeneration. The surge in organoid research is fueled by the need for physiologically relevant models to bridge the gap between traditional cell cultures and in vivo studies. Osteochondral organoids have emerged as a promising avenue in this pursuit, offering a better platform to mimic the intricate biological interactions within bone and cartilage. This review explores the significance of osteochondral organoids and the need for their development in advancing our understanding and treatment of bone and cartilage-related diseases. It summarizes osteochondral organoids' insights and research progress, focusing on their composition, materials, cell sources, and cultivation methods, as well as the concept of organoids on chips and application scenarios. Additionally, we address the limitations and challenges these organoids face, emphasizing the necessity for further research to overcome these obstacles and facilitate orthopedic regeneration.

Growing Role of 3D In Vitro Cell Cultures in the Study of Cellular and Molecular Mechanisms: Short Focus on Breast Cancer, Endometriosis, Liver and Infectious Diseases

Over the past decade, the development of three-dimensional (3D) models has increased exponentially, facilitating the unravelling of fundamental and essential cellular mechanisms by which cells communicate with each other, assemble into tissues and organs and respond to biochemical and biophysical stimuli under both physiological and pathological conditions. This section presents a concise overview of the most recent updates on the significant contribution of different types of 3D cell cultures including spheroids, organoids and organ-on-chip and bio-printed tissues in advancing our understanding of cellular and molecular mechanisms. The case studies presented include the 3D cultures of breast cancer (BC), endometriosis, the liver microenvironment and infections. In BC, the establishment of 3D culture models has permitted the visualization of the role of cancer-associated fibroblasts in the delivery of exosomes, as well as the significance of the physical properties of the extracellular matrix in promoting cell proliferation and invasion. This approach has also become a valuable tool in gaining insight into general and specific mechanisms of drug resistance. Given the considerable heterogeneity of endometriosis, 3D models offer a more accurate representation of the in vivo microenvironment, thereby facilitating the identification and translation of novel targeted therapeutic strategies. The advantages provided by 3D models of the hepatic environment, in conjunction with the high throughput characterizing various platforms, have enabled the elucidation of complex molecular mechanisms underlying various threatening hepatic diseases. A limited number of 3D models for gut and skin infections have been developed. However, a more profound comprehension of the spatial and temporal interactions between microbes, the host and their environment may facilitate the advancement of in vitro, ex vivo and in vivo disease models. Additionally, it may pave the way for the development of novel therapeutic approaches in diverse research fields. The interested reader will also find concluding remarks on the challenges and prospects of using 3D cell cultures for discovering cellular and molecular mechanisms in the research areas covered in this review.

The potential of organoids in renal cell carcinoma research

Renal cell carcinoma, a leading cause of death in urological malignancies, arises from the nephron. Its characteristics include diversity in disease biology, varied clinical behaviors, different prognoses, and diverse responses to systemic therapies. The term 'organoids' is used to describe structures resembling tissues created through the three-dimensional cultivation of stem cells in vitro. These organoids, when derived from tumor tissues, can retain the diversity of the primary tumor, mirror its spatial tissue structure, and replicate similar organ-like functions. In contrast to conventional two-dimensional cell cultures and the transplantation of tumor tissues into other organisms, organoids derived from tumors maintain the complexity and microenvironment of the original tumor tissue. This fidelity makes them a more reliable model for the development of cancer drugs, potentially accelerating the translation of these drugs to clinical use and facilitating personalized treatment options for patients. This review aims to summarize the recent advancements in the use of organoids for studying renal cell carcinoma, focusing on their cultivation, potential applications, and inherent limitations.

Ginkgo biloba: A Leaf of Hope in the Fight against Alzheimer's Dementia: Clinical Trial Systematic Review

Alzheimer's disease (AD) is a stealthy and progressive neurological disorder that is a leading cause of dementia in the global elderly population, imposing a significant burden on both the elderly and society. Currently, the condition is treated with medications that alleviate symptoms. Nonetheless, these drugs may not consistently produce the desired results and can cause serious side effects. Hence, there is a vigorous pursuit of alternative options to enhance the quality of life for patients. Ginkgo biloba (GB), an herb with historical use in traditional medicine, contains bioactive compounds such as terpenoids (Ginkgolides A, B, and C), polyphenols, organic acids, and flavonoids (quercetin, kaempferol, and isorhamnetin). These compounds are associated with anti-inflammatory, antioxidant, and neuroprotective properties, making them valuable for cognitive health. A systematic search across three databases using specific keywords-GB in AD and dementia-yielded 1702 documents, leading to the selection of 15 clinical trials for synthesis. In eleven studies, GB extract/EGb 761® was shown to improve cognitive function, neuropsychiatric symptoms, and functional abilities in both dementia types. In four studies, however, there were no significant differences between the GB-treated and placebo groups. Significant improvements were observed in scores obtained from the Mini-Mental State Examination (MMSE), Short Cognitive Performance Test (SKT), and Neuropsychiatric Inventory (NPI). While the majority of synthesized clinical trials show that Ginkgo biloba has promising potential for the treatment of these conditions, more research is needed to determine optimal dosages, effective delivery methods, and appropriate pharmaceutical formulations. Furthermore, a thorough assessment of adverse effects, exploration of long-term use implications, and investigation into potential drug interactions are critical aspects that must be carefully evaluated in future studies.

Emerging models for studying adipose tissue metabolism

Understanding adipose metabolism is essential for addressing obesity and related health concerns. However, the ethical and scientific pressure to animal testing, aligning with the 3Rs, has triggered the implementation of diverse alternative models for analysing anomalies in adipose metabolism. In this review, we will address this issue from various perspectives. Traditional adipocyte cell cultures, whether animal or human-derived, offer a fundamental starting point. These systems have their merits but may not fully replicate in vivo complexity. Established cell lines are valuable for high-throughput screening but may lack the authenticity of primary-derived adipocytes, which closely mimic native tissue. To enhance model sophistication, spheroids have been introduced. These three-dimensional cultures better mimicking the in vivo microenvironment, enabling the study of intricate cell-cell interactions, gene expression, and metabolic pathways. Organ-on-a-chip (OoC) platforms take this further by integrating multiple cell types into microfluidic devices, simulating tissue-level functions. Adipose-OoC (AOoC) provides dynamic environments with applications spanning drug testing to personalized medicine and nutrition. Beyond in vitro models, genetically amenable organisms (Caenorhabditis elegans, Drosophila melanogaster, and zebrafish larvae) have become powerful tools for investigating fundamental molecular mechanisms that govern adipose tissue functions. Their genetic tractability allows for efficient manipulation and high-throughput studies. In conclusion, a diverse array of research models is crucial for deciphering adipose metabolism. By leveraging traditional adipocyte cell cultures, primary-derived cells, spheroids, AOoCs, and lower organism models, we bridge the gap between animal testing and a more ethical, scientifically robust, and human-relevant approach, advancing our understanding of adipose tissue metabolism and its impact on health.

Recent Advances in 3D Cultures

Methods and protocols for creating complex 3D cell culture systems have been rapidly advancing in the past decade from the perspective of biomaterials [...].

Protective role of fetal bovine serum on PLHC-1 spheroids exposed to a mixture of plastic additives: A lipidomic perspective

The use of fetal bovine serum (FBS) in cell culture is being questioned for scientific and ethical reasons, prompting the exploration of alternative approaches. Nevertheless, the influence of FBS on cell functioning, especially in fish cells, has not been comprehensively examined. This study aims to evaluate the impact of FBS on the lipidome of PLHC-1 spheroids and investigate cellular and molecular responses to plastic additives in the presence/absence of FBS. Lipidomic analyses were conducted on PLHC-1 cell spheroids using liquid chromatography coupled with a high-resolution quadrupole time-of-flight mass spectrometer (HRMS-QToF). The removal of FBS from the culture medium for 24 h significantly changed the lipid profile of spheroids, resulting in a depletion of cholesterol esters (CEs), phosphatidylcholines (PCs) and lyso-phosphatidylcholines (LPCs), while ceramides and certain glycerophospholipids slightly increased. Additionally, the exclusion of FBS from the medium led to increased cytotoxicity caused by a mixture of plastic additives and increased lipidomic alterations, including an elevation of ceramides. This study emphasizes the protective role of serum components in fish liver spheroids against a mixture of plastic additives and underscores the importance of considering exposure conditions when studying metabolomic and lipidomic responses to toxicants.

Advantages of Using 3D Spheroid Culture Systems in Toxicological and Pharmacological Assessment for Osteogenesis Research

Bone differentiation is crucial for skeletal development and maintenance. Its dysfunction can cause various pathological conditions such as rickets, osteoporosis, osteogenesis imperfecta, or Paget's disease. Although traditional two-dimensional cell culture systems have contributed significantly to our understanding of bone biology, they fail to replicate the intricate biotic environment of bone tissue. Three-dimensional (3D) spheroid cell cultures have gained widespread popularity for addressing bone defects. This review highlights the advantages of employing 3D culture systems to investigate bone differentiation. It highlights their capacity to mimic the complex in vivo environment and crucial cellular interactions pivotal to bone homeostasis. The exploration of 3D culture models in bone research offers enhanced physiological relevance, improved predictive capabilities, and reduced reliance on animal models, which have contributed to the advancement of safer and more effective strategies for drug development. Studies have highlighted the transformative potential of 3D culture systems for expanding our understanding of bone biology and developing targeted therapeutic interventions for bone-related disorders. This review explores how 3D culture systems have demonstrated promise in unraveling the intricate mechanisms governing bone homeostasis and responses to pharmacological agents.

Vitamin C facilitates direct cardiac reprogramming by inhibiting reactive oxygen species

BACKGROUND

After myocardial infarction, the lost myocardium is replaced by fibrotic tissue, eventually progressively leading to myocardial dysfunction. Direct reprogramming of fibroblasts into cardiomyocytes via the forced overexpression of cardiac transcription factors Gata4, Mef2c, and Tbx5 (GMT) offers a promising strategy for cardiac repair. The limited reprogramming efficiency of this approach, however, remains a significant challenge.

METHODS

We screened seven factors capable of improving direct cardiac reprogramming of both mice and human fibroblasts by evaluating small molecules known to be involved in cardiomyocyte differentiation or promoting human-induced pluripotent stem cell reprogramming.

RESULTS

We found that vitamin C (VitC) significantly increased cardiac reprogramming efficiency when added to GMT-overexpressing fibroblasts from human and mice in 2D and 3D model. We observed a significant increase in reactive oxygen species (ROS) generation in human and mice fibroblasts upon Doxy induction, and ROS generation was subsequently reduced upon VitC treatment, associated with increased reprogramming efficiency. However, upon treatment with dehydroascorbic acid, a structural analog of VitC but lacking antioxidant properties, no difference in reprogramming efficiency was observed, suggesting that the effect of VitC in enhancing cardiac reprogramming is partly dependent of its antioxidant properties.

CONCLUSIONS

Our findings demonstrate that VitC supplementation significantly enhances the efficiency of cardiac reprogramming, partially by suppressing ROS production in the presence of GMT.

Target Prediction by Multiple Virtual Screenings: Analyzing the SARS-CoV-2 Phenotypic Screening by the Docking Simulations Submitted to the MEDIATE Initiative

Phenotypic screenings are usually combined with deconvolution techniques to characterize the mechanism of action for the retrieved hits. These studies can be supported by various computational analyses, although docking simulations are rarely employed. The present study aims to assess if multiple docking calculations can prove successful in target prediction. In detail, the docking simulations submitted to the MEDIATE initiative are utilized to predict the viral targets involved in the hits retrieved by a recently published cytopathic screening. Multiple docking results are combined by the EFO approach to develop target-specific consensus models. The combination of multiple docking simulations enhances the performances of the developed consensus models (average increases in EF1% value of 40% and 25% when combining three and two docking runs, respectively). These models are able to propose reliable targets for about half of the retrieved hits (31 out of 59). Thus, the study emphasizes that docking simulations might be effective in target identification and provide a convincing validation for the collaborative strategies that inspire the MEDIATE initiative. Disappointingly, cross-target and cross-program correlations suggest that common scoring functions are not specific enough for the simulated target.

[Thermoneutrality and animal study]

Animal models remain important for the study of human pathologies. The most widely used model (mouse) is an endothermic mammal like humans, maintained at ambient temperatures (22 °C). Its energy metabolism is overactivated, a situation rarely observed in humans thanks to various adaptations (clothing, heating…). The thermoneutral zone is defined as a range of ambient temperatures that allows an organism to regulate body temperature without using additional thermoregulatory processes. There are many examples of divergent results between studies conducted at 22 °C or at 30 °C (thermoneutrality for mice). Therefore, it seems essential to take into account the housing temperature both for animal welfare and for the relevance of the results.

Efficient Generation of Chondrocytes From Bone Marrow-Derived Mesenchymal Stem Cells in a 3D Culture System: Protocol for a Practical Model for Assessing Anti-Inflammatory Therapies

BACKGROUND

Chondrocytes are the primary cells responsible for maintaining cartilage integrity and function. Their role in cartilage homeostasis and response to inflammation is crucial for understanding the progression and potential therapeutic interventions for various cartilage-related disorders. Developing an accessible and cost-effective model to generate viable chondrocytes and to assess their response to different bioactive compounds can significantly advance our knowledge of cartilage biology and contribute to the discovery of novel therapeutic approaches.

OBJECTIVE

We developed a novel, streamlined protocol for generating chondrocytes from bone marrow-derived mesenchymal stem cells (BMSCs) in a 3D culture system that offers significant implications for the study of cartilage biology and the discovery of potential therapeutic interventions for cartilage-related and associated disorders.

METHODS

We developed a streamlined protocol for generating chondrocytes from BMSCs in a 3D culture system using an "in-tube" culture approach. This simple pellet-based 3D culture system allows for cell aggregation and spheroid formation, facilitating cell-cell and cell-extracellular matrix interactions that better mimic the in vivo cellular environment compared with 2D monolayer cultures. A proinflammatory chondrocyte model was created by treating the chondrocytes with lipopolysaccharide and was subsequently used to evaluate the anti-inflammatory effects of vitamin D, curcumin, and resveratrol.

RESULTS

The established protocol successfully generated a large quantity of viable chondrocytes, characterized by alcian blue and toluidine blue staining, and demonstrated versatility in assessing the anti-inflammatory effects of various bioactive compounds. The chondrocytes exhibited reduced inflammation, as evidenced by the decreased tumor necrosis factor-α levels, in response to vitamin D, curcumin, and resveratrol treatment.

CONCLUSIONS

Our novel protocol offers an accessible and cost-effective approach for generating chondrocytes from BMSCs and for evaluating potential therapeutic leads in the context of inflammatory chondrocyte-related diseases. Although our approach has several advantages, further investigation is required to address its limitations, such as the potential differences between chondrocytes generated using our protocol and those derived from other established methods, and to refine the model for broader applicability and clinical translation.

NAFLD-Related HCC: Focus on the Latest Relevant Preclinical Models

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and one of the deadliest cancers worldwide. Despite extensive research, the biological mechanisms underlying HCC's development and progression remain only partially understood. Chronic overeating and/or sedentary-lifestyle-associated obesity, which promote Non-Alcoholic Fatty Liver Disease (NAFLD), have recently emerged as worrying risk factors for HCC. NAFLD is characterized by excessive hepatocellular lipid accumulation (steatosis) and affects one quarter of the world's population. Steatosis progresses in the more severe inflammatory form, Non-Alcoholic Steatohepatitis (NASH), potentially leading to HCC. The incidence of NASH is expected to increase by up to 56% over the next 10 years. Better diagnoses and the establishment of effective treatments for NAFLD and HCC will require improvements in our understanding of the fundamental mechanisms of the disease's development. This review describes the pathogenesis of NAFLD and the mechanisms underlying the transition from NAFL/NASH to HCC. We also discuss a selection of appropriate preclinical models of NAFLD for research, from cellular models such as liver-on-a-chip models to in vivo models, focusing particularly on mouse models of dietary NAFLD-HCC.

Cultivation of Asexual Intraerythrocytic Stages of Plasmodium falciparum

Successfully developed in 1976, the continuous in vitro culture of Plasmodium falciparum has many applications in the field of malaria research. It has become an important experimental model that directly uses a human pathogen responsible for a high prevalence of morbidity and mortality in many parts of the world and is a major source of biological material for immunological, biochemical, molecular, and pharmacological studies. Until present, the basic techniques described by Trager and Jensen and Haynes et al. remain unchanged in many malaria research laboratories. Nonetheless, different factors, including culture media, buffers, serum substitutes and supplements, sources of erythrocytes, and conditions of incubation (especially oxygen concentration), have been modified by different investigators to adapt the original technique in their laboratories or enhance the in vitro growth of the parasites. The possible effects and benefits of these modifications for the continuous cultivation of asexual intraerythrocytic stages of P. falciparum, as well as future challenges in developing a serum-free cultivation system and axenic cultures, are discussed.

Acoustic and Magnetic Stimuli-Based Three-Dimensional Cell Culture Platform for Tissue Engineering

In a conventional two-dimensional (2D) culture method, cells are attached to the bottom of the culture dish and grow into a monolayer. These 2D culture methods are easy to handle, cost-effective, reproducible, and adaptable to growing many different types of cells. However, monolayer 2D cell culture conditions are far from those of natural tissue, indicating the need for a three-dimensional (3D) culture system. Various methods, such as hanging drop, scaffolds, hydrogels, microfluid systems, and bioreactor systems, have been utilized for 3D cell culture. Recently, external physical stimulation-based 3D cell culture platforms, such as acoustic and magnetic forces, were introduced. Acoustic waves can establish acoustic radiation force, which can induce suspended objects to gather in the pressure node region and aggregate to form clusters. Magnetic targeting consists of two components, a magnetically responsive carrier and a magnetic field gradient source. In a magnetic-based 3D cell culture platform, cells are aggregated by changing the magnetic force. Magnetic fields can manipulate cells through two different methods: positive magnetophoresis and negative magnetophoresis. Positive magnetophoresis is a way of imparting magnetic properties to cells by labeling them with magnetic nanoparticles. Negative magnetophoresis is a label-free principle-based method. 3D cell structures, such as spheroids, 3D network structures, and cell sheets, have been successfully fabricated using this acoustic and magnetic stimuli-based 3D cell culture platform. Additionally, fabricated 3D cell structures showed enhanced cell behavior, such as differentiation potential and tissue regeneration. Therefore, physical stimuli-based 3D cell culture platforms could be promising tools for tissue engineering.

Culture of vibrating microtome tissue slices as a 3D model in biomedical research

The basic idea behind the use of 3-dimensional (3D) tools in biomedical research is the assumption that the structures under study will perform at the best in vitro if cultivated in an environment that is as similar as possible to their natural in vivo embedding. Tissue slicing fulfills this premise optimally: it is an accessible, unexpensive, imaging-friendly, and technically rather simple procedure which largely preserves the extracellular matrix and includes all or at least most supportive cell types in the correct tissue architecture with little cellular damage. Vibrating microtomes (vibratomes) can further improve the quality of the generated slices because of the lateral, saw-like movement of the blade, which significantly reduces tissue pulling or tearing compared to a straight cut. In spite of its obvious advantages, vibrating microtome slices are rather underrepresented in the current discussion on 3D tools, which is dominated by methods as organoids, organ-on-chip and bioprinting. Here, we review the development of vibrating microtome tissue slices, the major technical features underlying its application, as well as its current use and potential advances, such as a combination with novel microfluidic culture chambers. Once fully integrated into the 3D toolbox, tissue slices may significantly contribute to decrease the use of laboratory animals and is likely to have a strong impact on basic and translational research as well as drug screening.