Functional morphometric analysis in cellular behaviors: shape and size matter

Introducing FISCAS, a Tool for the Effective Generation of Single Cell MALDI-MSI Data

We introduce Fluorescence Integrated Single-Cell Analysis Script (FISCAS), which combines fluorescence microscopy with MALDI-MSI to streamline single-cell analysis. FISCAS enables automated selection of tight measurement regions, thereby reducing the acquisition of off-target pixels, and makes use of established algorithms for cell segmentation and coregistration to rapidly compile single-cell spectra. MALDI-compatible staining of membranes, nuclei, and lipid droplets allows the collection of fluorescence data prior to the MALDI-MSI measurement on a timsTOF fleX MALDI-2. Usefulness of the software is demonstrated by the example of THP-1 cells during stimulated differentiation into macrophages at different time points. In this proof-of-principle study, FISCAS was used to automatically generate single-cell mass spectra along with a wide range of morphometric parameters for a total number of roughly 1300 cells collected at 24, 48, and 72 h after the onset of stimulation. Data analysis of the combined morphometric and single-cell mass spectrometry data shows significant molecular heterogeneity within the cell population at each time point, indicating an independent differentiation of each individual cell rather than a synchronized mechanism. Here, the grouping of cells based on their molecular phenotype revealed an overall clearer distinction of the different phases of differentiation into macrophages and delivered an increased number of lipid signals as possible markers compared with traditional bulk analysis. Utilizing the linkage between mass spectrometric data and fluorescence microscopy confirmed the expected positive correlation between lipid droplet staining and the overall signal for triacylglyceride (TG), demonstrating the usefulness of this multimodal approach.

Investigation of Cell Mechanics and Migration on DDR2-Expressing Neuroblastoma Cell Line

Neuroblastoma is a devastating disease accounting for ~15% of all childhood cancer deaths. Collagen content and fiber association within the tumor stroma influence tumor progression and metastasis. High expression levels of collagen receptor kinase, Discoidin domain receptor II (DDR2), are associated with the poor survival of neuroblastoma patients. Additionally, cancer cells generate and sustain mechanical forces within their environment as a part of their normal physiology. Despite this, evidence regarding whether collagen-activated DDR2 signaling dysregulates these migration forces is still elusive. To address these questions, a novel shRNA DDR2 knockdown neuroblastoma cell line (SH-SY5Y) was engineered to evaluate the consequence of DDR2 on cellular mechanics. Atomic force microscopy (AFM) and traction force microscopy (TFM) were utilized to unveil the biophysical altercations. DDR2 downregulation was found to significantly reduce proliferation, cell stiffness, and cellular elongation. Additionally, DDR2-downregulated cells had decreased traction forces when plated on collagen-coated elastic substrates. Together, these results highlight the important role that DDR2 has in reducing migration mechanics in neuroblastoma and suggest DDR2 may be a promising novel target for future therapies.

Magneto-Enzymatic Microgels for Precise Hydrogel Sculpturing

The inclusion of hollow channels in tissue-engineered hydrogels is crucial for mimicking the natural physiological conditions and facilitating the delivery of nutrients and oxygen to cells. Although bio-fabrication techniques provide diverse strategies to create these channels, many require sophisticated equipment and time-consuming protocols. Herein, collagenase, a degrading agent for methacrylated gelatin hydrogels, and magnetic nanoparticles (MNPs) are combined and processed into enzymatically active spherical structures using a straightforward oil bath emulsion methodology. The generated microgels are then used to microfabricate channels within biomimetic hydrogels via a novel sculpturing approach that relied on the precise coupling of protein-enzyme pairs (for controlled local degradation) and magnetic actuation (for directional control). Results show that the sculpting velocity can be tailored by adjusting the magnetic field intensity or concentration of MNPs within the microgels. Additionally, varying the magnetic field position or microgel size generated diverse trajectories and channels of different widths. This innovative technology improves the viability of encapsulated cells through enhanced medium transport, outperforming non-sculpted hydrogels and offering new perspectives for hydrogel vascularization and drug/biomolecule administration. Ultimately, this novel concept can help design fully controlled channels in hydrogels or soft materials, even those with complex tortuosity, in a single wireless top-down biocompatible step.

Characterizing Cellular Physiological States with Three-Dimensional Shape Descriptors for Cell Membranes

The shape of a cell as defined by its membrane can be closely associated with its physiological state. For example, the irregular shapes of cancerous cells and elongated shapes of neuron cells often reflect specific functions, such as cell motility and cell communication. However, it remains unclear whether and which cell shape descriptors can characterize different cellular physiological states. In this study, 12 geometric shape descriptors for a three-dimensional (3D) object were collected from the previous literature and tested with a public dataset of ~400,000 independent 3D cell regions segmented based on fluorescent labeling of the cell membranes in Caenorhabditis elegans embryos. It is revealed that those shape descriptors can faithfully characterize cellular physiological states, including (1) cell division (cytokinesis), along with an abrupt increase in the elongation ratio; (2) a negative correlation of cell migration speed with cell sphericity; (3) cell lineage specification with symmetrically patterned cell shape changes; and (4) cell fate specification with differential gene expression and differential cell shapes. The descriptors established may be used to identify and predict the diverse physiological states in numerous cells, which could be used for not only studying developmental morphogenesis but also diagnosing human disease (e.g., the rapid detection of abnormal cells).

Engineered Tumor-Immune Microenvironment On A Chip to Study T Cell-Macrophage Interaction in Breast Cancer Progression

Evolving knowledge about the tumor-immune microenvironment (TIME) is driving innovation in designing novel therapies against hard-to-treat breast cancer. Targeting the immune components of TIME has emerged as a promising approach for cancer therapy. While recent immunotherapies aim at restoring antitumor immunity, counteracting tumor escape remains challenging. Hence there is a pressing need to better understand the complex tumor-immune crosstalk within TIME. Considering this imperative, this study aims at investigating the crosstalk between the two abundant immune cell populations within the breast TIME-macrophages and T cells, in driving tumor progression using an organotypic 3D in vitro tumor-on-a-chip (TOC) model. The TOC features distinct yet interconnected organotypic tumor and stromal entities. This triculture platform mimics the complex TIME, embedding the two immune populations in a suitable 3D matrix. Analysis of invasion, morphometric measurements, and flow cytometry results underscores the substantial contribution of macrophages to tumor progression, while the presence of T cells is associated with a deceleration in the migratory behavior of both cancer cells and macrophages. Furthermore, cytokine analyses reveal significant upregulation of leptin and RANTES (regulated on activation, normal T Cell expressed and secreted) in triculture. Overall, this study highlights the complexity of TIME and the critical role of immune cells in cancer progression.

TempEasy 3D Hydrogel Coculture System Provides Mechanistic Insights into Prostate Cancer Bone Metastasis

Patients diagnosed with advanced prostate cancer (PCa) often experience incurable bone metastases; however, a lack of relevant experimental models has hampered the study of disease mechanisms and the development of therapeutic strategies. In this study, we employed the recently established Temperature-based Easy-separable (TempEasy) 3D cell coculture system to investigate PCa bone metastasis. Through coculturing PCa and bone cells for 7 days, our results showed a reduction in PCa cell proliferation, an increase in neovascularization, and an enhanced metastasis potential when cocultured with bone cells. Additionally, we observed increased cell proliferation, higher stemness, and decreased bone matrix protein expression in bone cells when cocultured with PCa cells. Furthermore, we demonstrated that the stiffness of the extracellular matrix had a negligible impact on molecular responses in both primary (PCa cells) and distant malignant (bone cells) sites. The TempEasy 3D hydrogel coculture system is an easy-to-use and versatile coculture system that provides valuable insights into the mechanisms of cell-cell communication and interaction in cancer metastasis.

Anti-inflammatory potency of novel ecto-5'-nucleotidase/CD73 inhibitors in astrocyte culture model of neuroinflammation

Three novel cytosine-derived α,β-methylene diphosphonates designated MRS4598, MRS4552, and MRS4602 were tested in the range of 1 × 10-9 to 1 × 10-3 M for their efficacy and potency in inhibiting membrane-bound ecto-5'-nucleotidase/CD73 activity in primary astrocytes in vitro. The compounds were also tested for their ability to attenuate the reactive astrocyte phenotype induced by proinflammatory cytokines. The main findings are as follows: A) The tested compounds induced concentration-dependent inhibition of CD73 activity, with maximal inhibition achieved at ∼1 × 10-3M; B) All compounds showed high inhibitory potency, as reflected by IC50 values in the submicromolar range; C) All compounds showed high binding capacity, as reflected by Ki values in the low nanomolar range; D) Among the tested compounds, MRS4598 showed the highest inhibitory efficacy and potency, as reflected by IC50 and Ki values of 0.11 μM and 18.2 nM; E) Neither compound affected astrocyte proliferation and cell metabolic activity at concentrations near to IC50; E) MRS4598 was able to inhibit CD73 activity in reactive astrocytes stimulated with TNF-α and to induce concentration-dependent inhibition of CD73 in reactive astrocytes stimulated with IL-1β, with an order of magnitude higher IC50 value; F) MRS4598 was the only compound tested that was able to induce shedding of the CD73 from astrocyte membranes and to enhance astrocyte migration in the scratch wound migration assay, albeit at concentration well above its IC50 value. Given the role of CD73 in neurodegenerative diseases, MRS4598, MRS4552, and MRS4602 are promising pharmacological tools for the treatment of neurodegeneration and neuroinflammation.

Morphomigrational description as a new approach connecting cell's migration with its morphology

The examination of morphology and migration of cells plays substantial role in understanding the cellular behaviour, being described by plethora of quantitative parameters and models. These descriptions, however, treat cell migration and morphology as independent properties of temporal cell state, while not taking into account their strong interdependence in adherent cells. Here we present the new and simple mathematical parameter called signed morphomigrational angle (sMM angle) that links cell geometry with translocation of cell centroid, considering them as one morphomigrational behaviour. The sMM angle combined with pre-existing quantitative parameters enabled us to build a new tool called morphomigrational description, used to assign the numerical values to several cellular behaviours. Thus, the cellular activities that until now were characterized using verbal description or by complex mathematical models, are described here by a set of numbers. Our tool can be further used in automatic analysis of cell populations as well as in studies focused on cellular response to environmental directional signals.

Nanomechanical Characterization of Ovarian Cancer Cell Lines as a Marker of Response to 2c Treatment

Epithelial ovarian cancers (EOCs) are a heterogeneous group of tumors with different molecular and clinical features. In past decades, few improvements have been achieved in terms of EOC management and treatment efficacy, such that the 5-year survival rate of patients remained almost unchanged. A better characterization of EOCs' heterogeneity is needed to identify cancer vulnerabilities, stratify patients and adopt proper therapies. The mechanical features of malignant cells are emerging as new biomarkers of cancer invasiveness and drug resistance that can further improve our knowledge of EOC biology and allow the identification of new molecular targets. In this study, we determined the inter and intra-mechanical heterogeneity of eight ovarian cancer cell lines and their association with tumor invasiveness and resistance to an anti-tumoral drug with cytoskeleton depolymerization activity (2c).

Platelet-Derived Extracellular Vesicles Promote Tenogenic Differentiation of Stem Cells on Bioengineered Living Fibers

Tendon mimetic scaffolds that recreate the tendon hierarchical structure and niche have increasing potential to fully restore tendon functionality. However, most scaffolds lack biofunctionality to boost the tenogenic differentiation of stem cells. In this study, we assessed the role of platelet-derived extracellular vesicles (EVs) in stem cells' tenogenic commitment using a 3D bioengineered in vitro tendon model. First, we relied on fibrous scaffolds coated with collagen hydrogels encapsulating human adipose-derived stem cells (hASCs) to bioengineer our composite living fibers. We found that the hASCs in our fibers showed high elongation and cytoskeleton anisotropic organization, typical of tenocytes. Moreover, acting as biological cues, platelet-derived EVs boosted the hASCs' tenogenic commitment, prevented phenotypic drift, enhanced the deposition of the tendon-like extracellular matrix, and induced lower collagen matrix contraction. In conclusion, our living fibers provided an in vitro system for tendon tissue engineering, allowing us to study not only the tendon microenvironment but also the influence of biochemical cues on stem cell behavior. More importantly, we showed that platelet-derived EVs are a promising biochemical tool for tissue engineering and regenerative medicine applications that are worthy of further exploration, as paracrine signaling might potentiate tendon repair and regeneration.

Retinal neuroblast migration and ganglion cell layer organization require the cytoskeletal-interacting protein Mllt11

BACKGROUND

The vertebrate retina is an organized laminar structure comprised of distinct cell types populating three nuclear layers. During development, each retinal cell type follows a stereotypical temporal order of genesis, differentiation, and migration, giving rise to its stratified organization. Once born, the precise positioning of cells along the apico-basal (radial) axis of the retina is critical for subsequent connections to form, relying on highly orchestrated migratory processes. While these processes are critical for visual function to arise, the regulators of cellular migration and retinal lamination remain largely unexplored.

RESULTS

We report a role for a microtubule-interacting protein, Mllt11 (myeloid/lymphoid or mixed-lineage leukemia; translocated to chromosome 11/All1 fused gene from chromosome 1q) in mammalian retinal cell migration during retinogenesis. We show that Mllt11 loss-of-function in mouse retinal neuroblasts affected the migration of ganglion and amacrine cells into the ganglion cell layer and led to their aberrant accumulation in the inner nuclear and plexiform layers.

CONCLUSIONS

We demonstrate a role for Mllt11 in neuroblast migration and formation of the ganglion cell layer of the retina.

Quantifying F-actin patches in single melanoma cells using total-internal reflection fluorescence microscopy

Total-internal reflection fluorescence (TIRF) microscope is a unique technique for selective excitation of only those fluorophore molecules in a cellular environment, which are located at the sub-diffraction axial distance of a cell's contact-area. Despite this prominent feature of the TIRF microscope, making quantitative use of this technique has been a challenge, since the excitation intensity strongly depends on the axial position of a fluorophore molecule. Here, we present an easy-implemented data analysis method to quantitatively characterize the fluorescent signal, without considering the intensity-value. We use F-actin patches in single-melanoma cells as an example and define two quantities of elongation and surface density for F-actin patches at the contact-area of a melanoma cell. The elongation parameter can evaluate the dispersion of F-actin patches at the contact-area of a cell and is useful to classify the attaching, spreading, and expanding stages of a cell. Following that, we present the profile of the surface density of F-actin patches as a quantity to probe the spatio-temporal distribution of the F-actin patches at the contact-area of a cell. The data analysis methods that are proposed here will also be applicable in the image analysis of the other advanced optical microscopic methods.

Metal accumulation and morphofunctional damage in coelomocytes of earthworm collected from industrially contaminated soil of Kolkata, India

The current study is aimed to assess the ecotoxicological effects of toxic metals and seasonal shift of the physicochemical characteristics of soil in an endogeic earthworm Metaphire posthuma of industrially contaminated soil of Calcutta leather complex. The accumulation of cadmium, chromium, lead and mercury was quantitated in whole earthworms and coelomocytes. The accumulation of metals was derived to be high in the coelomocytes than whole earthworms. Morphofunctional shift in coelomocytes indicated a high level of metal toxicity in soil inhabitants. The shift in differential coelomocyte count and cellular damage including intense cytoplasmic vacuolation and membrane blebbing of coelomocytes of M. posthuma of contaminated soil were suggestive to a state of immunocompromisation in the same species. Shift in the generation of nitric oxide and activity of inducible nitric oxide synthase indicated a possible immunosuppression in earthworm. Depletion in the acetylcholinesterase activity of coelomocytes indicated neurotoxicity of metals leached from the dumped wastes in Calcutta leather complex. Integrated biomarker response based analysis was carried out to assess the biomarker potential of experimental endpoints of M. posthuma to monitor metal toxicity in soil.

Freestanding Magnetic Microtissues for Tissue Engineering Applications

A long-sought goal in tissue engineering (TE) is the development of tissues able to recapitulate the complex architecture of the native counterpart. Microtissues, by resembling the functional units of living structures, can be used to recreate tissues' architecture. Howbeit, microfabrication methodologies fail to reproduce cell-based tissues with uniform shape. At the macroscale, complex tissues are already produced by magnetic-TE using solely magnetized cells as building materials. The enhanced extracellular matrix (ECM) deposition guaranties the conservation of tissues' architecture, leading to a successful cellular engraftment. Following the same rational, now the combination of a versatile microfabrication-platform is proposed with magnetic-TE to generate robust micro-tissues with complex architecture for TE purposes. Small tissue units with circle, square, and fiber-like shapes are designed with high fidelity acting as building blocks for engineering complex tissues. Notably, freestanding microtissues maintain their geometry after 7 days post-culturing, overcoming the challenges of microtissues fabrication. Lastly, the ability of microtissues in invading distinct tissue models while releasing trophic factors is substantiated in methacryloyl laminarin (LAM) and platelet lysates (PLMA) hydrogels. By simply using cells as building units and such microfabrication-platform, the fabrication of complex multiscale and multifunctional tissues with clinical relevance is envisaged, including for therapies or disease models.

Visible-light-responsive reduced graphene oxide/g-C3N4/TiO2 composite nanocoating for photoelectric stimulation of neuronal and osteoblastic differentiation

rGO/g-C3N4/TiO2 nanocoating was fabricated on Ti-based implant for photoelectric stimulation of bone and nerve repair. The ternary nanocoating exerted greater photoelectric effects on enhancing osteoblastic differentiation and neurite outgrowth.

Fabrication of Quasi-2D Shape-Tailored Microparticles using Wettability Contrast-Based Platforms

The ability to fabricate materials with ultrathin architectures enables the breakthrough of low-dimensional structures with high surface area that showcase distinctive properties from their bulk counterparts. They are exploited in a wide range of fields, including energy harvesting, catalysis, and biomedicine. Despite such versatility, the fine tuning of the lateral dimensions and geometry of these structures remains challenging. Prepatterned platforms gain significant attention as enabling technologies to process materials with highly controlled shapes and dimensions. Herein, different nanometer-thick particles of various lateral sizes and geometries (e.g., squares, circles, triangles, hexagons) are processed with high precision and definition, taking advantage of the wettability contrast of oleophilic-oleophobic patterned surfaces. Quasi-2D polymeric microparticles with high shape- and size-fidelity can be retrieved as freestanding objects in a single step. These structures show cell-mediated pliability, and their integration in gravity-enforced human adipose-derived stem cell spheroids leads to an enhanced metabolic activity and a modulated secretion of proangiogenic factors.

Inhibitory effects of Camellia japonica on cell inflammation and acute rat reflux esophagitis

Background

Excessive and continuous inflammation may be the main cause of various immune system diseases. Reflux esophagitis (RE) is a common gastroesophageal reflux disease (GERD). Camellia japonica has high medicinal value and has long been used as a traditional herbal hemostatic medicine in China and Korea. The purpose of this study is to explore the antioxidant and anti-inflammatory activities of CJE and its protective effect on RE.

Materials and methods

Buds from C. japonica plants were collected in the mountain area of Jeju, South Korea. Dried C. japonica buds were extracted with 75% ethanol. DPPH and ABTS radical scavenging assay were evaluated according to previous method. The ROS production and anti-inflammatory effects of C. japonica buds ethanol extract (CJE) were evaluated on LPS-induced RAW 264.7 cell inflammation. The protective effects of CJE on RE were conducted in a RE rat model.

Results

CJE eliminated over 50% of DPPH and ABTS radical at concentration of 100 and 200 µg/mL, respectively. CJE alleviated changes in cell morphology, reduced production of ROS, NO and IL-1β. Also, down-regulated expression levels of iNOS, TNF-α, phosphorylated NF-κB, IκBα, and JNK/p38/MAPK. CJE reduced esophageal tissue damage ratio (40.3%) and attenuation of histological changes. In addition, CJE down-regulated the expression levels of TNF-α, IL-1β, COX-2 and phosphorylation levels of NF-κB and IκBα in esophageal tissue.

Conclusions

CJE possesses good anti-oxidation and anti-inflammatory activity, and can improve RE in rats caused by gastric acid reflux. Therefore, CJE is a natural material with good anti-oxidant and anti-inflammatory activity and has the possibility of being a candidate phytomedicine source for the treatment of RE.

Mesenchymal stem cells induce PD-L1 expression through the secretion of CCL5 in breast cancer cells

Various factors in the tumor microenvironment (TME) regulate the expression of PD-L1 in cancer cells. In TME, mesenchymal stem cells (MSCs) play a crucial role in tumor progression, metastasis, and drug resistance. Emerging evidence suggests that MSCs can modulate the immune-suppression capacity of TME through the stimulation of PD-L1 expression in various cancers; nonetheless, their role in the induction of PD-L1 in breast cancer remained elusive. Here, we assessed the potential of MSCs in the stimulation of PD-L1 expression in a low PD-L1 breast cancer cell line and explored its associated cytokine. We assessed the expression of MSCs-related genes and their correlation with PD-L1 across 1826 breast cancer patients from the METABRIC cohort. After culturing an ER+/differentiated/low PD-L1 breast cancer cells with MSCs conditioned-medium (MSC-CM) in a microfluidic device, a variety of in-vitro assays was carried out to determine the role of MSC-CM in breast cancer cells' phenotype plasticity, invasion, and its effects on induction of PD-L1 expression. In-silico analysis showed a positive association between MSCs-related genes and PD-L1 expression in various types of breast cancer. Through functional assays, we revealed that MSC-CM not only prompts a phenotype switch but also stimulates PD-L1 expression at the protein level through secretion of various cytokines, especially CCL5. Treatment of MSCs with cytokine inhibitor pirfenidone showed a significant reduction in the secretion of CCL5 and consequently, expression of PD-L1 in breast cancer cells. We concluded that MSCs-derived CCL5 may act as a PD-L1 stimulator in breast cancer.

The role of ubiquitin ligase E3A in polarized contact guidance and rescue strategies in UBE3A-deficient hippocampal neurons

Background

Although neuronal extracellular sensing is emerging as crucial for brain wiring and therefore plasticity, little is known about these processes in neurodevelopmental disorders. Ubiquitin protein ligase E3A (UBE3A) plays a key role in neurodevelopment. Lack of UBE3A leads to Angelman syndrome (AS), while its increase is among the most prevalent genetic causes of autism (e.g., Dup15q syndrome). By using microstructured substrates that can induce specific directional stimuli in cells, we previously found deficient topographical contact guidance in AS neurons, which was linked to a dysregulated activation of the focal adhesion pathway.

Methods

Here, we study axon and dendrite contact guidance and neuronal morphological features of wild-type, AS, and UBE3A-overexpressing neurons (Dup15q autism model) on micrograting substrates, with the aim to clarify the role of UBE3A in neuronal guidance.

Results

We found that loss of axonal contact guidance is specific for AS neurons while UBE3A overexpression does not affect neuronal directional polarization along microgratings. Deficits at the level of axonal branching, growth cone orientation and actin fiber content, focal adhesion (FA) effectors, and actin fiber-binding proteins were observed in AS neurons. We tested different rescue strategies for restoring correct topographical guidance in AS neurons on microgratings, by either UBE3A protein re-expression or by pharmacological treatments acting on cytoskeleton contractility. Nocodazole, a drug that depolymerizes microtubules and increases cell contractility, rescued AS axonal alignment to the gratings by partially restoring focal adhesion pathway activation. Surprisingly, UBE3A re-expression only resulted in partial rescue of the phenotype.

Conclusions

We identified a specific in vitro deficit in axonal topographical guidance due selectively to the loss of UBE3A, and we further demonstrate that this defective guidance can be rescued to a certain extent by pharmacological or genetic treatment strategies. Overall, cytoskeleton dynamics emerge as important partners in UBE3A-mediated contact guidance responses. These results support the view that UBE3A-related deficits in early neuronal morphogenesis may lead to defective neuronal connectivity and plasticity.

A Human Organotypic Microfluidic Tumor Model Permits Investigation of the Interplay between Patient-Derived Fibroblasts and Breast Cancer Cells

Tumor-stroma interactions significantly influence cancer cell metastasis and disease progression. These interactions are partly comprised of the cross-talk between tumor and stromal fibroblasts, but the key molecular mechanisms within the cross-talk that govern cancer invasion are still unclear. Here, we adapted our previously developed microfluidic device as a 3D in vitro organotypic model to mechanistically study tumor-stroma interactions by mimicking the spatial organization of the tumor microenvironment on a chip. We cocultured breast cancer and patient-derived fibroblast cells in 3D tumor and stroma regions, respectively, and combined functional assessments, including cancer cell migration, with transcriptome profiling to unveil the molecular influence of tumor-stroma cross-talk on invasion. This led to the observation that cancer-associated fibroblasts (CAF) enhanced invasion in 3D by inducing expression of a novel gene of interest, glycoprotein nonmetastatic B (GPNMB), in breast cancer cells, resulting in increased migration speed. Importantly, knockdown of GPNMB blunted the influence of CAF on enhanced cancer invasion. Overall, these results demonstrate the ability of our model to recapitulate patient-specific tumor microenvironments to investigate the cellular and molecular consequences of tumor-stroma interactions. SIGNIFICANCE: An organotypic model of tumor-stroma interactions on a microfluidic chip reveals that CAFs promote invasion by enhancing expression of GPNMB in breast cancer cells.

Tropoelastin-Coated Tendon Biomimetic Scaffolds Promote Stem Cell Tenogenic Commitment and Deposition of Elastin-Rich Matrix

Tendon tissue engineering strategies that recreate the biophysical and biochemical native microenvironment have a greater potential to achieve regeneration. Here, we developed tendon biomimetic scaffolds using mechanically competent yarns of poly-ε-caprolactone, chitosan, and cellulose nanocrystals to recreate the inherent tendon hierarchy from a nano-to-macro scale. These were then coated with tropoelastin (TROPO) through polydopamine (PDA) linking, to mimic the native extracellular matrix (ECM) composition and elasticity. Both PDA and TROPO coatings decreased surface stiffness without masking the underlying substrate. We found that human adipose-derived stem cells (hASCs) seeded onto these TROPO biomimetic scaffolds more rapidly acquired their spindle-shape morphology and high aspect ratio characteristic of tenocytes. Immunocytochemistry shows that the PDA and TROPO-coated surfaces boosted differentiation of hASCs toward the tenogenic lineage, with sustained expression of the tendon-related markers scleraxis and tenomodulin up to 21 days of culture. Furthermore, these surfaces enabled the deposition of a tendon-like ECM, supported by the expression of collagens type I and III, tenascin, and decorin. Gene expression analysis revealed a downregulation of osteogenic and fibrosis markers in the presence of TROPO when compared with the control groups, suggesting proper ECM deposition. Remarkably, differentiated cells exposed to TROPO acquired an elastogenic profile due to the evident elastin synthesis and deposition, contributing to the formation of a more mimetic matrix in comparison with the PDA-coated and uncoated conditions. In summary, our biomimetic substrates combining biophysical and biological cues modulate stem cell behavior potentiating their long-term tenogenic commitment and the production of an elastin-rich ECM.

Morphology-Based Distinction Between Healthy and Pathological Cells Utilizing Fourier Transforms and Self-Organizing Maps

The appearance and the movements of immune cells are driven by their environment. As a reaction to a pathogen invasion, the immune cells are recruited to the site of inflammation and are activated to prevent a further spreading of the invasion. This is also reflected by changes in the behavior and the morphological appearance of the immune cells. In cancerous tissue, similar morphokinetic changes have been observed in the behavior of microglial cells: intra-tumoral microglia have less complex 3-dimensional shapes, having less-branched cellular processes, and move more rapidly than those in healthy tissue. The examination of such morphokinetic properties requires complex 3D microscopy techniques, which can be extremely challenging when executed longitudinally. Therefore, the recording of a static 3D shape of a cell is much simpler, because this does not require intravital measurements and can be performed on excised tissue as well. However, it is essential to possess analysis tools that allow the fast and precise description of the 3D shapes and allows the diagnostic classification of healthy and pathogenic tissue samples based solely on static, shape-related information. Here, we present a toolkit that analyzes the discrete Fourier components of the outline of a set of 2D projections of the 3D cell surfaces via Self-Organizing Maps. The application of artificial intelligence methods allows our framework to learn about various cell shapes as it is applied to more and more tissue samples, whilst the workflow remains simple.

Peptide-based coatings for flexible implantable neural interfaces

In the last decade, the use of flexible biosensors for neuroprosthetic and translational applications has widely increased. Among them, the polyimide (PI)-based thin-film electrodes got a large popularity. However, the usability of these devices is still hampered by a non-optimal tissue-device interface that usually compromises the long-term quality of neural signals. Advanced strategies able to improve the surface properties of these devices have been developed in the recent past. Unfortunately, most of them are not easy to be developed and combined with micro-fabrication processes, and require long-term efforts to be testable with human subjects. Here we show the results of the design and in vitro testing of an easy-to-implement and potentially interesting coating approach for thin-film electrodes. In particular, two biocompatible coatings were obtained via covalent conjugation of a laminin-derived peptide, CAS-IKVAV-S (IKV), with polyimide sheets that we previously functionalized with vinyl- and amino- groups (PI_v and PI_a respectively). Both the engineered coatings (PI_v+IKV and PI_a+IKV) showed morphological and chemical properties able to support neuronal adhesion, neurite sprouting, and peripheral glial cell viability while reducing the fibroblasts contamination of the substrate. In particular, PI_v+IKV showed promising results that encourage further in vivo investigation and pave the way for a new generation of peptide-coated thin-film electrodes.

Morphometric study of adipocytes on breast cancer by means of photonic microscopy and image analysis

Worldwide, breast cancer (BrCa) is currently the leading cause of deaths associated to malignant lesions in adult women. Given that some studies have mentioned that peritumoral adipocytes may contribute to breast carcinogenesis, present work sought to quantitative evaluate the morphometry of these cells in a group of adult women. Three thousand six hundred sixty four breast adipocytes, that came from biopsies of a group of adult females with different types of breast carcinomas (ductal, lobular, and mixed) and one with normal tissues, were evaluated through an image analysis (IA) process regarding six morphometric descriptors: area (A), perimeter (P), Feret diameter (F_D ), aspect ratio (AR), roundness factor (RF), and fractal dimension of cellular contour (FD_C ). Data showed that the adipocytes of the normal tissues group were bigger (A: 3398 ± 2331 µm² , P: 239 ± 83 µm, and F_D : 79.9 ± 24.5 µm) than those from BrCa samples (A: 2860 ± 1933 µm² , P: 214 ± 66 µm, and F_D : 73.2 ± 22.5 µm), and presented a more irregular contour (FD_C of 1.370 ± 0.037 for normal group and of 1.335 ± 0.049 for the oncologic one). Moreover, it could be accounted that adipocytes of mixed carcinomas were largest (F_D : 75.1 ± 22.4 µm) than those of lobular lesions (F_D : 61.6 ± 22.6 µm), while the adipocytes of ductal carcinomas were the most oval (AR: 1.421 ± 0.524) and roughest (FD_C : 1.324 ± 0.050) cells. IA results suggest that BrCa lesions can be categorized through a quantitative morphometric evaluation of peritumoral adipocytes. These findings could let the development of an analytical tool to help the Pathologist to enhance the accuracy of the oncologic diagnose.

Hierarchical thermoplastic rippled nanostructures regulate Schwann cell adhesion, morphology and spatial organization

Periodic ripples are a variety of anisotropic nanostructures that can be realized by ion beam irradiation on a wide range of solid surfaces. Only a few authors have investigated these surfaces for tuning the response of biological systems, probably because it is challenging to directly produce them in materials that well sustain long-term cellular cultures. Here, hierarchical rippled nanotopographies with a lateral periodicity of ∼300 nm are produced from a gold-irradiated germanium mold in polyethylene terephthalate (PET), a biocompatible polymer approved by the US Food and Drug Administration for clinical applications, by a novel three-step embossing process. The effects of nano-ripples on Schwann Cells (SCs) are studied in view of their possible use for nerve-repair applications. The data demonstrate that nano-ripples can enhance short-term SC adhesion and proliferation (3-24 h after seeding), drive their actin cytoskeleton spatial organization and sustain long-term cell growth. Notably, SCs are oriented perpendicularly with respect to the nanopattern lines. These results provide information about the possible use of hierarchical nano-rippled elements for nerve-regeneration protocols.

Novel application of the published kinase inhibitor set to identify therapeutic targets and pathways in triple negative breast cancer subtypes

Triple negative breast cancers (TNBCs) have high recurrence and metastasis rates. Acquisition of a mesenchymal morphology and phenotype in addition to driving migration is a consequential process that promotes metastasis. Although some kinases are known to regulate a mesenchymal phenotype, the role for a substantial portion of the human kinome remains uncharacterized. Here we evaluated the Published Kinase Inhibitor Set (PKIS) and screened a panel of TNBC cell lines to evaluate the compounds’ effects on a mesenchymal phenotype. Our screen identified 36 hits representative of twelve kinase inhibitor chemotypes based on reversal of the mesenchymal cell morphology, which was then prioritized to twelve compounds based on gene expression and migratory behavior analyses. We selected the most active compound and confirmed mesenchymal reversal on transcript and protein levels with qRT-PCR and Western Blot. Finally, we utilized a kinase array to identify candidate kinases responsible for the EMT reversal. This investigation shows the novel application to identify previously unrecognized kinase pathways and targets in acquisition of a mesenchymal TNBC phenotype that warrant further investigation. Future studies will examine specific roles of the kinases in mechanisms responsible for acquisition of the mesenchymal and/or migratory phenotype.

3D Mimicry of Native-Tissue-Fiber Architecture Guides Tendon-Derived Cells and Adipose Stem Cells into Artificial Tendon Constructs

Tendon and ligament (T/L) function is intrinsically related with their unique hierarchically and anisotropically organized extracellular matrix. Their natural healing capacity is, however, limited. Here, continuous and aligned electrospun nanofiber threads (CANT) based on synthetic/natural polymer blends mechanically reinforced with cellulose nanocrystals are produced to replicate the nanoscale collagen fibrils grouped into microscale collagen fibers that compose the native T/L. CANT are then incrementally assembled into 3D hierarchical scaffolds, resulting in woven constructions, which simultaneously mimic T/L nano-to-macro architecture, nanotopography, and nonlinear biomechanical behavior. Biological performance is assessed using human-tendon-derived cells (hTDCs) and human adipose stem cells (hASCs). Scaffolds nanotopography and microstructure induce a high cytoskeleton elongation and anisotropic organization typical of tendon tissues. Moreover, the expression of tendon-related markers (Collagen types I and III, Tenascin-C, and Scleraxis) by both cell types, and the similarities observed on their expression patterns over time suggest that the developed scaffolds not only prevent the phenotypic drift of hTDCs, but also trigger tenogenic differentiation of hASCs. Overall, these results demonstrate a feasible approach for the scalable production of 3D hierarchical scaffolds that exhibit key structural and biomechanical properties, which can be advantageously explored in acellular and cellular T/L TE strategies.

An integrated enhancement and reconstruction strategy for the quantitative extraction of actin stress fibers from fluorescence micrographs

BACKGROUND

The stress fibers are prominent organization of actin filaments that perform important functions in cellular processes such as migration, polarization, and traction force generation, and whose collective organization reflects the physiological and mechanical activities of the cells. Easily visualized by fluorescence microscopy, the stress fibers are widely used as qualitative descriptors of cell phenotypes. However, due to the complexity of the stress fibers and the presence of other actin-containing cellular features, images of stress fibers are relatively challenging to quantitatively analyze using previously developed approaches, requiring significant user intervention. This poses a challenge for the automation of their detection, segmentation, and quantitative analysis.

RESULT

Here we describe an open-source software package, SFEX (Stress Fiber Extractor), which is geared for efficient enhancement, segmentation, and analysis of actin stress fibers in adherent tissue culture cells. Our method made use of a carefully chosen image filtering technique to enhance filamentous structures, effectively facilitating the detection and segmentation of stress fibers by binary thresholding. We subdivided the skeletons of stress fiber traces into piecewise-linear fragments, and used a set of geometric criteria to reconstruct the stress fiber networks by pairing appropriate fiber fragments. Our strategy enables the trajectory of a majority of stress fibers within the cells to be comprehensively extracted. We also present a method for quantifying the dimensions of the stress fibers using an image gradient-based approach. We determine the optimal parameter space using sensitivity analysis, and demonstrate the utility of our approach by analyzing actin stress fibers in cells cultured on various micropattern substrates.

CONCLUSION

We present an open-source graphically-interfaced computational tool for the extraction and quantification of stress fibers in adherent cells with minimal user input. This facilitates the automated extraction of actin stress fibers from fluorescence images. We highlight their potential uses by analyzing images of cells with shapes constrained by fibronectin micropatterns. The method we reported here could serve as the first step in the detection and characterization of the spatial properties of actin stress fibers to enable further detailed morphological analysis.

Neuregulin 1 functionalization of organic fibers for Schwann cell guidance

The repair of peripheral nerve lesions is a clinical problem where the functional recovery is often far from being satisfactory, although peripheral nerves generally retain good potential for regeneration. Here, we develop a novel scaffold approach based on bioactive fibers of poly(ε-caprolactone) where nanotopographical guidance and neuregulin 1 (NRG1) cues are combined. We interface them with rat primary Schwann cells (SCs), the peripheral glial cells that drive initial regeneration of injured nerves, and found that the combination of NRG1 with parallel nano-fibrous topographies is effective in improving SC growth up to 72 h, alignment to fiber topography, and bipolar differentiation, opening original perspectives for nerve repair applications.

Roughness gradients on zirconia for rapid screening of cell-surface interactions: Fabrication, characterization and application

Roughness is one of the key parameters for successful osseointegration of dental implants. The understanding of how roughness affects cell response is thus crucial to improve implant performance. Surface gradients, which allow rapid and systematic investigations of cell-surface interactions, have the potential to facilitate this task. In this study, a novel method aiming to produce roughness gradients at the surface of zirconia using hydrofluoric acid etching was implemented. The topography was exhaustively characterized at the microscale and nanoscale by white light interferometry and atomic force microscopy, including the analysis of amplitude, spatial, hybrid, functional, and fractal parameters. A rapid screening of the influence of roughness on human mesenchymal stem cell morphology was conducted and potential correlations between roughness parameters and cell morphology were investigated. The roughness gradient induced significant changes in cell area (p < 0.001), aspect ratio (p = 0.01), and solidity (p = 0.026). Nanoroughness parameters were linearly correlated to cell solidity (p < 0.005), while microroughness parameters appeared nonlinearly correlated to cell area, highlighting the importance of multiscale optimization of implant topography to induce the desired cell response. The gradient method proposed here drastically reduces the efforts and resources necessary to study cell-surface interactions and provides results directly transferable to industry. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2502-2514, 2016.

pH-Responsive Wormlike Micelles with Sequential Metastasis Targeting Inhibit Lung Metastasis of Breast Cancer

Cancer metastasis is the main cause for the high mortality in breast cancer patients. Herein, we first report succinobucol-loaded pH-responsive wormlike micelles (PWMs) with sequential targeting capability to inhibit lung metastasis of breast cancer. PWMs can in a first step be delivered specifically to the sites of metastases in the lungs and then enable the intracellular pH-stimulus responsive drug release in cancer cells to improve the anti-metastatic effect. PWMs are identified as nanofibrillar assemblies with a diameter of 19.9 ± 1.9 nm and a length within the 50-200 nm range, and exhibited pH-sensitive drug release behavior in response to acidic intracellular environments. Moreover, PWMs can obviously inhibit the migration and invasion abilities of metastatic 4T1 breast cancer cells, and reduce the expression of the metastasis-associated vascular cell adhesion molecule-1 (VCAM-1) at 400 ng mL(-1) of succinobucol. In particular, PWMs can induce a higher specific accumulation in lung and be specifically delivered to the sites of metastases in lung, thereby leading to an 86.6% inhibition on lung metastasis of breast cancer. Therefore, the use of sequentially targeting PWMs can become an encouraging strategy for specific targeting and effective treatment of cancer metastasis.

Regulation of breast cancer cell behaviours by the physical microenvironment constructed via projection microstereolithography

A considerable number of studies have examined how intrinsic factors regulate breast cancer cell behaviours; however, physical microenvironmental cues may also modulate cellular morphology, proliferation, and migration and mechanical properties.

Schwann Cell Contact Guidance versus Boundary -Interaction in Functional Wound Healing along Nano and Microstructured Membranes

Peripheral nerve transection is often encountered after trauma and can lead to long-term/permanent loss of sensor/motor functionality. Here, the effect of pure contact interaction of nano/microgrooved substrates on Schwann cells (SCs) is studied in view of their possible use for nerve-repair applications. Elastomeric gratings (GRs; i.e., alternating lines of ridges and grooves) are developed with different lateral periods (1-20 μm) and depths (0.3-2.5 μm), leading to two distinct cell-material interaction regimes: contact guidance (grating period < cell body diameter) and boundary guidance (grating period ≥ cell body diameter). Here, it is shown that boundary guidance leads to the best single-cell polarization, actin organization, and single-cell directional migration. Remarkably, contact guidance is instead more effective in driving collective SC migration and improves functional wound healing. It is also demonstrated that this behavior is linked to the properties of the SC monolayers on different GRs. SCs on large-period GRs are characterized by N-Cadherin downregulation and enhanced single-cell scattering into the wound with respect to SCs on small-period GRs, indicating a less compact monolayer characterized by looser cell-cell junctions in the boundary guidance regime. The present results provide information on the impact of specific sub-micrometer topographical elements on SC functional response, which can be exploited for nerve-regeneration applications.

Role of Cytoskeletal Tension in the Induction of Cardiomyogenic Differentiation in Micropatterned Human Mesenchymal Stem Cell

The role of biophysical induction methods such as cell micropatterning in stem cell differentiation has been well documented previously. However, the underlying mechanistic linkage of the engineered cell shape to directed lineage commitment remains poorly understood. Here, it is reported that micropatterning plays an important role in regulating the optimal cytoskeletal tension development in human mesenchymal stem cell (hMSC) via cell mechanotransduction pathways to induce cardiomyogenic differentiation. Cells are grown on fibronectin strip patterns to control cell polarization and morphology. These patterned cells eventually show directed commitment toward the myocardial lineage. The cell's mechanical properties (cell stiffness and cell traction forces) are observed to be very different for cells that have committed to the myocardial lineage when compared with that of control. These committed cells have mechanical properties that are significantly lower indicating a correlation between the micropatterning-induced differentiation and actomyosin-generated cytoskeletal tension within patterned cells. To study this correlation, patterned cells are treated with RhoA pathway inhibitor. Severely down-regulated cardiomyogenic marker expression is observed in those treated patterned cells, thus emphasizing the direct dependence of hMSCs differentiation fate on the cytoskeletal tension.