Contact inhibition controls cell survival and proliferation via YAP/TAZ-autophagy axis

Harnessing the power of physicochemical material property screening to direct breast epithelial and breast cancer cells

Understanding cell-material interactions is crucial for advancing biomedical applications, influencing cellular behavior and medical device performance. Material properties can be manipulated to direct cell responses, benefiting applications from regenerative medicine to implantable devices such as silicone breast implants. Knowledge about the interaction differences between healthy and cancer cells with implants may guide implant design to more precisely influence cell adhesion and proliferation of healthy cells while inhibiting cancer cells, tailoring outcomes to specific cellular responses. To show-case this potential, breast epithelial cells and breast cancer cells were investigated regarding their interaction with a broad range of combined physicochemical properties. This study employed a silicone-based high-throughput screening method utilizing Double Orthogonal Gradients (DOGs) to investigate the influence of topography, stiffness, and wettability on breast epithelial cells (MCF10a) and breast cancer cells (MCF7). Results show distinct cellular responses, including decreased proliferation rates in both MCF10a and MCF7 cells with the introduction of surface topography and the dominant influence of wettability on cell adhesion, proliferation, and cluster formation. The screening identified specific regions of interest (ROIs) where MCF10a cell proliferation outperformed MCF7 cells and that topography inhibits cluster formation (tumorigenesis), offering potential prospects for the creation of novel implant surfaces.

Autophagy induced by mechanical stress sensitizes cells to ferroptosis by NCOA4-FTH1 axis

Ferroptosis is an iron-dependent regulated form of cell death implicated in various diseases, including cancers, with its progression influenced by iron-dependent peroxidation of phospholipids and dysregulation of the redox system. Whereas the extracellular matrix of tumors provides mechanical cues influencing tumor initiation and progression, its impact on ferroptosis and its mechanisms remains largely unexplored. In this study, we reveal that heightened mechanical tension sensitizes cells to ferroptosis, whereas decreased mechanics confers resistance. Mechanistically, reduced mechanical tension reduces intracellular free iron levels by enhancing FTH1 protein expression. Additionally, low mechanics significantly diminishes NCOA4, pivotal in mediating FTH1 phase separation-induced ferritinophagy. Targeting NCOA4 effectively rescues ferroptosis susceptibility under low mechanical tension through modulation of FTH1 phase separation-driven autophagy. In conclusion, our findings demonstrate that mechanics regulates iron metabolism via NCOA4-FTH1 phase separation-mediated autophagy, thereby influencing ferroptosis sensitivity and offering promising therapeutic avenues for future exploration.Abbreviations: ACO1: aconitase 1; ATG5: autophagy related 5; DMSO: dimethyl sulfoxide; EGFP: enhanced green fluorescent protein; FACS: fluorescence-activated cell sorting; FER-1: ferrostatin-1; FTH1: ferritin heavy chain 1; FTL: ferritin light chain; GPX4: glutathione peroxidase 4; IR: ionizing radiation; IREB2: iron responsive element binding protein 2; NCOA4: nuclear receptor coactivator 4; NFE2L2: NFE2 like bZIP transcription factor 2; NOPP: norepinephrine; PBS: phosphate-buffered saline; PI: propidium iodide; RSL3: (1S,3 R)-RSL3; TCGA: The Cancer Genome Atlas; WWTR1: WW domain containing transcription regulator 1; YAP1: Yes1 associated transcriptional regulator.

ITIH4 attenuates acute lung injury by Fe-containing particulate matter in mice via Hippo pathway in type II alveolar epithelial cells

BACKGROUND

Metals in particulate matter (PM), like iron (Fe), were associated with lung injury. Inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4) was suggested to inhibit lung inflammation. However, the effect of metals in PM, particularly Fe, on lung inflammation involving ITIH4 remained unclear.

METHODS

We investigated the effects of recombinant ITIH4 (rITIH4) against acute lung injury in C57BL/6JNarl and B6.Sftpc-CreERT2;Ai14(RCL-tdT)-D mice exposed to Fe-containing PM. Mice were exposed to diesel exhaust particles (DEP) or soluble iron (FeCl₃) via intratracheal instillation, while rITIH4 treatment was administered intranasally after exposure. Lung function, Fe levels (both bulk and single-cell by inductively-coupled plasma mass spectrometry (ICP-MS) and single-cell ICP-MS, respectively), inflammatory cell infiltration, and Hippo pathway regulation in type II alveolar epithelial cells (AECII) were assessed.

RESULTS

We observed correlation between lung function changes and Fe levels, both in bulk and single-cell Fe in peripheral blood mononuclear cells. Single-cell RNA sequencing of the control group identified AECII-related cells characterized by high Sftpc, Sftpa1, Mzb1, B3 gnt5, Cacna1e, and Agbl1 expression. rITIH4 treatment in DEP-exposed mice restored Hippo pathway Cdh1, Itih4, Pdpn, Wwtr1, and Yap1 in AECII. rITIH4 reversed DEP- and Fe-induced increases in neutrophil infiltration, neutrophil-to-lymphocyte ratio, and monocyte depletion in bronchoalveolar lavage fluid (BALF). rITIH4 reduced BALF CXCL1/KC levels by DEP and serum 8-isoprostane levels by Fe. rITIH4 also reduced DEP-induced lung damage, increased ⍺-catenin and p-YAP in Fe-exposed mice, and pTAZ/TAZ ratio in both DEP- and Fe-exposed mice. rITIH4 increased pYAP/YAP ratio in DEP-exposed mice while decreasing LC3BII/I ratio in Fe-exposed mice.

CONCLUSION

ITIH4 attenuated acute lung injury in mice exposed to PM, specifically Fe, by modulating the Hippo pathway in AECII.

Unraveling the influence of astrocytes on endothelial cell transcription: Towards understanding blood-brain barrier in vitro models' dynamics

In recent years, considerable advancements have been made in developing in vitro models to better understand the complex dynamics of the blood-brain barrier (BBB) and its critical role in neurological health and disease. Incorporating astrocytes into these models introduces an essential layer of complexity, allowing for a more comprehensive investigation of the cellular interactions and regulatory mechanisms that maintain BBB integrity and functionality. Despite these advances, the specific influence of astrocytes on endothelial cells in in vitro systems remains inadequately explored. This study addresses this gap by examining the transcriptional changes in primary human brain microvascular endothelial cells (HBMECs) cocultured with human astrocytes (HAs). Our findings demonstrate that astrocytes profoundly modulate endothelial pathways involved in cell cycle regulation and division while upregulating genes associated with BBB integrity, protective mechanisms, and transporter activity. Furthermore, astrocytes significantly enhanced transendothelial electrical resistance (TEER) and reduced permeability to tracer Cascade Blue dye, confirming their functional impact on BBB models. By providing a comprehensive human primary cell dataset, this research underscores the pivotal role astrocytes play in shaping endothelial cell gene expression and function in contact coculture systems. These results emphasize the necessity of incorporating astrocytes into in vitro BBB models to accurately replicate neurovascular interactions. Ultimately, this study advances our understanding of BBB physiology and highlights the importance of refining in vitro models to better reflect the complexity of the human neurovascular environment, with potential implications for studying neurological disorders and drug delivery strategies.

The impact of cell density variations on nanoparticle uptake across bioprinted A549 gradients

Introduction

The safe-by-design of engineered nanoparticles (NPs) for any application requires a detailed understanding of how the particles interact with single cells. Most studies are based on two-dimensional, uniformly dense cell cultures, which do not represent the diverse and inhomogeneous cell environments found in situ. In-vitro models that accurately represent tissue complexity, including realistic cell densities, are essential to increase the predictive accuracy of studies on cell-NP interactions. This study uses a bioprinted cell gradient model to examine the relation between cell density and NP uptake in one dish.

Method

A549 lung epithelial cell density gradients within single inserts were produced with a bioprinter by modulating inter-droplet distances. After two days in culture, cells were exposed to Cy5-labeled silica NPs (SiO2 NPs, ∼112 nm, 20 μg/mL) for up to 48 h. Confocal fluorescence microscopy and 3D image analysis were used to quantify NP uptake, cell surface area, and cell volume. The relationship between NP uptake and the other parameters was then investigated statistically.

Results

Bioprinting enabled the creation of reproducible linear cell density gradients, allowing controlled modeling of density variations while preserving cell viability throughout the experiment. Increasing inter-droplet distances, from 0.1 mm to 0.6 mm, were used to achieve uniformly decreasing cell densities. SiO2 NP uptake per cell was around 50% higher in low-density regions compared to high-density areas across all time points, i.e., 6, 24, and 48 h post-exposure. This inverse relationship correlated with greater average cell surface area in lower-density regions, while differences in the proliferation rates of the A549 cells at varying densities did not significantly impact uptake, did not significantly impact uptake.

Conclusion

SiO2 NP uptake is significantly enhanced at lower cell densities, mainly due to the increased available surface area, revealing potential cell-NP interaction differences in tissues that present cell density variability. Our drop-on-demand bioprinting gradient model successfully supports the implementation of cell density gradients in in-vitro models to increase their relevance as new approach methodologies (NAMs) for next-generation risk assessment strategies.

Extracellular matrix mechanical cues (dys)regulate metabolic redox homeostasis due to impaired autophagic flux

BACKGROUND

Extracellular matrix (ECM) stiffness is increasingly recognized as a critical regulator of cellular behaviour, governing processes such as proliferation, differentiation, and metabolism. Neurodegenerative diseases are characterized by mitochondrial dysfunction, oxidative stress, impaired autophagy, and progressive softening of the brain tissue, yet research into how mechanical cues influence cellular metabolism in this context remains scarce.

MATERIALS AND METHODS

In this study, we evaluated the long-term effects of brain-compliant, soft ECM on mitochondrial bioenergetics, redox balance, and autophagic capacity in human neuroblastoma (SH-SY5Y) and mouse hippocampal (HT22) cell lines, as well as primary mouse neurons.

RESULTS

We observed that prolonged exposure to soft ECM does not impact cell proliferative capacity of neuronal cells but results in mitochondrial bioenergetic dysfunction, redox imbalance, and disrupted autophagic flux. These findings were consistently validated across both human and mouse neuronal cells. Our data indicate a decreased maximal autophagic capacity in cells exposed to long-term soft ECM, potentially due to an imbalance in autophagosome formation and degradation, as demonstrated by decreased LC3 II levels following chloroquine-induced autophagic flux inhibition. This impairment in autophagy was coupled with increased cellular oxidative stress, further indicating metabolic alterations.

CONCLUSIONS

These findings emphasize the critical role of ECM stiffness in regulating neuronal cell metabolism and suggest that prolonged exposure to soft ECM may mimic key aspects of neurodegenerative disease pathology, thereby enhancing the physiological relevance of in vitro models. This study underscores the necessity for further research into ECM mechanics as a contributing factor in neurodegenerative disease progression and as a potential target for therapeutic strategies.

Process intensification of cultivated meat production through microcarrier addition strategy optimisation

The use of microcarriers (MCs) is currently the most promising method for scaling up bovine satellite cell (bSC) cultures for cultivated meat production. Thanks to the inherent ability of the cells to migrate from one MC to another, also known as bead-to-bead transfer, the need for cell detachment is limited to a minimum, leading to a seamless seeding train. With this study, we aim to intensify the bioprocessing of bSCs in serum-free medium, by exploring the parameters influencing bead-to-bead transfer and cell growth and by optimising the seeding conditions and the MC addition strategy. Keeping production scale bioprocessing requirements into consideration, such as maximisation of fold increase within the same system, we have grown bSCs in up to 80 cm2/ml MC concentrations, using seeding cell densities of 1,000 to 4,750 cells/cm2. We also demonstrated optimisation of the MC addition strategy by determining an optimal confluence range (15,000 to 25,000 cells/cm2) for MC additions and by maximising the MC expansion ratio to 10, without impairing growth. Finally, to ensure scalability of these findings, we successfully applied them at a 3 L bioreactor scale.

Chemical reprogramming culture for the expansion of salivary gland epithelial basal progenitor cells

BACKGROUND

Salivary gland (SG) hypofunction presents a significant clinical challenge with limited treatment options. SG epithelial cells offer a promising approach due to their intrinsic tissue specificity and regenerative potential. However, the lack of efficient culture methods has hindered their clinical use.

METHODS

This study presents a chemical reprogramming culture (CRC) system that utilizes a combination of three small molecules for the long-term two-dimensional culture of human SG epithelial progenitor cells. We characterized the cultured cells, measured their organoid-forming efficiencies, and assessed their differentiation potential. To evaluate the therapeutic efficacy of the SG basal progenitor cells (SG-BPCs), we administered them into a mouse model with radiation-induced SG hypofunction and assessed the functional recovery.

RESULTS

By utilizing optimal concentrations of the small molecules Y-27632, A83-01, and LDN193189, the SG epithelial cells achieved over 50 population doubling levels (PD) within 80 d, surpassing the Hayflick limit. β-galactosidase and Terminal deoxynucleotidyl transferase dUTP nick end labeling staining confirmed that these small molecules inhibited cellular senescence and apoptosis, respectively. The cells expressed SG basal ductal cell markers KRT5, KRT19, and SOX9, with increased expression levels observed from PD5 to PD40. Notably, these expanded cells were able to differentiate into various SG cell types, including acinar and myoepithelial cells, indicating that SG-basal progenitor cells (SG-BPCs) were selectively proliferated using our CRC method. To assess the therapeutic potential of the expanded SG-BPCs, they were administered to mice with radiation-induced SG hypofunction. The treatment successfully restored SG function.

CONCLUSION

Our findings demonstrate that our CRC system is an effective method for the long-term culture of SG-BPCs. This advancement holds significant promise for the development of SG epithelial progenitor-based therapies to treat SG hypofunction.

Diffusion-aware compartment model of the cellular uptake of ^{18}F-fluorodeoxyglucose

Compartment models are widely used in fields such as epidemiology and biomedicine to describe the exchange of uniformly distributed materials between interconnected compartments. However, their application in biological fluids is limited by the assumption of infinitely large diffusivity, especially in environments such as tumors or subcutaneous tissue, where diffusion is considerably lower. To address this, we develop a diffusion-aware compartment model that maintains the simplicity of traditional compartment models while offering greater accuracy. We conducted experiments on the uptake of ^{18}F-fluorodeoxyglucose (FDG), a radionuclide, by cells grown in culture plates and found a good agreement between the measured and predicted cellular radioactivity. We identify two critical dimensionless parameters that compare the amount of FDG (i) replenished by diffusion and (ii) available in the culture medium to the amount of FDG taken up by cells. We demonstrate that the diffusion-aware compartment model reduces to the three-compartment model when FDG diffusion is fast relative to cellular uptake, and it further simplifies to the two-compartment model when sufficient FDG is available in the culture medium. The semianalytic solutions of the diffusion-aware compartment model can be easily extended to study other scenarios, such as drug transport and bubble growth dynamics.

Rbbp6-Mediated Bmal1 Ubiquitination Inhibits YAP1 Signaling Pathway to Promote Ferroptosis in Diabetes-Induced Testicular Damage

BACKGRUOUND

Diabetes-induced testicular damage (DITD) is a common complication of diabetes. We investigated underlying mechanism of retinoblastoma-binding protein 6 (Rbbp6)-mediated brain and muscle ARNT-like 1 (Bmal1) ubiquitination in modulating ferroptosis in DITD.

METHODS

Spermatogenic cell apoptosis and viability were measured by flow cytometry and cell counting kit 8 (CCK-8), respectively. The impact of Rbbp6 and Bmal1 on ferroptosis was assessed by determining expression of ferroptosis markers glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11), and levels of malondialdehyde (MDA), glutathione (GSH), iron, and lipid peroxidation. Co-immunoprecipitation was performed to determine the interaction between Rbbp6 and Bmal1, as well as the ubiquitination level of Bmal1. The expression levels of Rbbp6, Bmal1, Yes-associated protein 1 (YAP1), ferroptosis markers, and testicular steroidogenic enzymes were tested by Western blot.

RESULTS

Bmal1 protein expression was significantly downregulated, while Rbbp6 was upregulated in DITD mouse model and high glucose (HG)-induced GC-1 spg cells. Overexpression of Bmal1 improved testicular injury in diabetic mice, reduced 4-hydroxynonenal (4-HNE), MDA, iron levels, and increased expression levels of GPX4, SLC7A11, GSH, as well as testicular steroidogenic enzymes. Rbbp6 decreased Bmal1 level through promoting its ubiquitination. Meanwhile, Rbbp6 knockdown inhibited the ferroptosis of HG-induced GC-1 spg cells, which were abolished by silencing Bmal1. In addition, knockdown of YAP1 or treatment with ferroptosis inducer erastin blocked the above effects caused by Bmal1 overexpression.

CONCLUSION

Rbbp6-mediated Bmal1 ubiquitination suppressed YAP1 pathway, promoting ferroptosis in DITD. This study highlighted Rbbp6/Bmal1/YAP1 axis as a potential therapeutic target for mitigating DITD.

Same same but different? How blood and lymphatic vessels induce cell contact inhibition

Endothelial cells (ECs) migrate, sprout, and proliferate in response to (lymph)angiogenic mitogens, such as vascular endothelial growth factors. When ECs reach high confluency and encounter spatial confinement, they establish mature cell-cell junctions, reduce proliferation, and enter a quiescent state through a process known as contact inhibition. However, EC quiescence is modulated not only by spatial confinement but also by other mechano-environmental factors, including blood or lymph flow and extracellular matrix properties. Changes in physical forces and intracellular signaling can disrupt contact inhibition, resulting in aberrant proliferation and vascular dysfunction. Therefore, it is critical to understand the mechanisms by which endothelial cells regulate contact inhibition. While contact inhibition has been well studied in blood endothelial cells (BECs), its regulation in lymphatic endothelial cells (LECs) remains largely unexplored. Here, we review the current knowledge on extrinsic stimuli and intrinsic molecular pathways that govern endothelial contact inhibition and highlight nuanced differences between BECs and LECs. Furthermore, we provide perspectives for future research on lymphatic contact inhibition. A deeper understanding of the BEC and LEC-specific pathways underlying contact inhibition may enable targeted modulation of this process in blood or lymphatic vessels with relevance to lymphatic or blood vascular-specific disorders.

Extracellular Matrix Stiffness Modulates Myopia Scleral Remodeling Through Integrin/F-Actin/YAP Axis

Purpose

Scleral extracellular matrix (ECM) remodeling and weakened scleral stiffness are characteristic of myopia. The purpose of this study was to investigate the precise underlying mechanisms of scleral remodeling regulated by mechanical signals emanating from the ECM.

Methods

The expression and regulation of YES-associated protein (YAP) were confirmed in human samples or guinea pig myopia models by Western blot (WB) or ELISA. To mimic the biomechanical microenvironment associated with myopia, stiff (50 kPa) and soft (8 kPa) substrates were established. The underlying mechanisms were further investigated by quantitative real-time RT-PCR, WB, and fluorescence staining in cells treated with siRNAs, plasmids or inhibitors. In vivo, a YAP activator, inhibitor and F-actin polymerization facilitator were applied to evaluate their therapeutic significance for myopia.

Results

Our findings revealed that YAP expression is decreased in the sclera of guinea pigs and humans with myopia. Under mechanical stimuli, YAP functions as a mediator, transducing mechanical signals and modulating collagen expression. Furthermore, integrin α1β1 acts as a regulator of YAP and operates through modification of the F-actin cytoskeleton. Specifically, in response to mechanical forces, integrin α1β1 modulates F-actin restructuring. This modified actin cytoskeletal architecture subsequently facilitates the nuclear translocation of YAP, ultimately leading to the suppression of COL1A1 expression.

Conclusions

Our results suggest that the integrin α1β1-F-actin-YAP-COL1A1 axis constitutes a vital regulatory mechanism intrinsically associated with the pathogenesis of myopia.

Tetramethylpyrazine attenuates sodium arsenite-induced acute kidney injury by improving the autophagic flux blockade via a YAP1-Nrf2-p62-dependent mechanism

With increased application, sodium arsenite (AS III)-induced acute kidney injury (AI-AKI) is becoming a new clinical challenge, but its potential pathogenesis remains poorly studied. Our previous data demonstrated that inducing autophagy and mitochondrial dysfunction in renal tubular cells are important links of AI-AKI and could be inhibited by tetramethylpyrazine (TMP). Recently, co-transcription factor YAP1 is reported to control autophagy and is mandatory to stimulate autophagic flux. This study constructed in vitro and in vivo models using clinically related dosages of AS III. Mitophagy, upregulated YAP1 expression, and Nrf2 activation were observed, with upregulation of p62 representing the occurrence of autophagic flux blockade. In HK-2 cells, oxidative stress induced by AS III promoted sustained Nrf2 activation, which enhanced p62 transcription at an early phase. Subsequently, p62 accumulation induced Nrf2 nuclear translocation, which in turn promoted p62 expression, forming a feedback loop to induce autophagic flux blockade, which was aggravated by the autophagic flux blocker chloroquine (CQ). TMP reversed such processes and protected tubular cells, while silencing YAP1 and Nrf2 attenuated TMP renoprotections. YAP1 agonist PY-60 increased Nrf2 expression, while YAP1 knockdown counteracted it and diminished TMP effect on autophagic flux. Furthermore, blocking Nrf2 caused YAP1 accumulation. CO-IP and immunofluorescence co-localization results confirmed co-nuclear translocations of YAP1 bound to dissociated Nrf2 that induced autophagic flux blockade. In conclusion, the present study identified novel mechanisms that TMP alleviated AI-AKI by improving the autophagic flux blockade via a YAP1-Nrf2-p62-dependent mechanism.

Autophagy, aging, and age-related neurodegeneration

Autophagy is a conserved mechanism that degrades damaged or superfluous cellular contents and enables nutrient recycling under starvation conditions. Many neurodegeneration-associated proteins are autophagy substrates, and autophagy upregulation ameliorates disease in many animal models of neurodegeneration by enhancing the clearance of toxic proteins, proinflammatory molecules, and dysfunctional organelles. Autophagy inhibition also induces neuronal and glial senescence, a phenomenon that occurs with increasing age in non-diseased brains as well as in response to neurodegeneration-associated stresses. However, aging and many neurodegeneration-associated proteins and mutations impair autophagy. This creates a potentially detrimental feedback loop whereby the accumulation of these disease-associated proteins impairs their autophagic clearance, facilitating their further accumulation and aggregation. Thus, understanding how autophagy interacts with aging, senescence, and neurodegenerative diseases in a temporal, cellular, and genetic context is important for the future clinical application of autophagy-modulating therapies in aging and neurodegeneration.

D-ribose-5-phosphate inactivates YAP and functions as a metabolic checkpoint

BACKGROUND

Targeting glucose uptake by glucose transporter (GLUT) inhibitors is a therapeutic opportunity, but efforts on GLUT inhibitors have not been successful in the clinic and the underlying mechanism remains unclear. We aim to identify the key metabolic changes responsible for cancer cell survival from glucose limitation and elucidate its mechanism.

METHODS

The level of phosphorylated YAP was analyzed with Western blotting and Phos-tag immunoblotting. Glucose limitation-induced metabolic changes were analyzed using targeted metabolomics (600MRM). The anti-cancer role of metabolite was examined using colony formation assay and APCmin/+ mice. Co-immunoprecipitation, LS-MS, qRT-PCR, and immunofluorescence were performed to explore the underlying mechanisms.

RESULTS

We found that D-Ribose-5-phosphate (D5P), a product of the pentose phosphate pathway connecting glucose metabolism and nucleotide metabolism, functions as a metabolic checkpoint to activate YAP under glucose limitation to promote cancer cell survival. Mechanistically, in glucose-deprived cancer cells, D5P is decreased, which facilitates the interaction between MYH9 and LATS1, resulting in MYH9-mediated LATS1 aggregation, degradation, and further YAP activation. Interestingly, activated YAP further promotes purine nucleoside phosphorylase (PNP)-mediated breakdown of purine nucleoside to restore D5P in a feedback manner. Importantly, D5P synergistically enhances the tumor-suppressive effect of GLUT inhibitors and inhibits cancer progression in mice.

CONCLUSIONS

Our study identifies D5P as a metabolic checkpoint linking glucose limitation stress and YAP activation, indicating that D5P may be a potential anti-cancer metabolite by enhancing glucose limitation sensitivity.

Combinational regenerative inductive effect of bio-adhesive hybrid hydrogels conjugated with hiPSC-derived myofibers and its derived EVs for volumetric muscle regeneration

In regenerative medicine, extracellular vesicles (EVs) possess the potential to repair injured cells by delivering modulatory factors. However, the therapeutic effect of EVs in large-scale tissue defects, which are subject to prolonged timelines for tissue architecture and functional restoration, remains poorly understood. In this study, we introduce EVs and cell-tethering hybrid hydrogels composed of tyramine-conjugated gelatin (GelTA) that can be in-situ crosslinked with EVs derived from human induced pluripotent stem cell-derived myofibers (hiPSC-myofibers) and hiPSC-muscle precursor cells. This hybrid hydrogel sustains the release of EVs and provides a beneficial nano-topography and mechanical properties for creating a favorable extracellular matrix. Secreted EVs from the hiPSC-myofibers contain specific microRNAs, potentially improving myogenesis and angiogenesis. Herein, we demonstrate increased myogenic markers and fusion/differentiation indexes through the combinatory effects of EVs and integrin-mediated adhesions in the 3D matrix. Furthermore, we observe a unique impact of EVs, which aid in maintaining the viability and phenotype of myofibers under harsh environments. The hybrid hydrogel in-situ crosslinked with hiPSCs and EVs is facilely used to fabricate large-scale muscle constructs by the stacking of micro-patterned hydrogel domains. Later, we confirmed a combinational effect, whereby muscle tissue regeneration and functional restoration were improved, via an in vivo murine volumetric muscle loss model.

Investigating the effects of stereotactic body radiation therapy on pancreatic tumor hypoxia and microvasculature in an orthotopic mouse model using intravital fluorescence microscopy

Despite decades of improvements in cytotoxic therapy, the current standard of care for locally advanced pancreatic cancer (LAPC) provides, on average, only a few months of survival benefit. Stereotactic Body Radiation Therapy (SBRT), a technique that accurately delivers high doses of radiation to tumors in fewer fractions, has emerged as a promising therapy to improve local control of LAPC; however, its effects on the tumor microenvironment and hypoxia remain poorly understood. To explore how SBRT affects pancreatic tumors, we combined an orthotopic mouse model of pancreatic cancer with an intravital microscopy platform to visualize changes to the in vivo tumor microenvironment in real-time. Mice received SBRT (5 × 8 Gy) or were left untreated, and were imaged before and 1, 4, 7, and 14 days after treatment (n = 7/group). A fluorescent human pancreatic cancer cell line (BxPC3-DsRed) engineered to express GFP under hypoxic conditions (driven by hypoxia-inducible factor, HIF) was used to monitor tumor hypoxia. Immunohistochemical staining was also performed on tissues to validate in vivo data. Our findings demonstrate a persistent decrease in pancreatic tumor hypoxia as early as one day after SBRT. This coincided with a decrease in both tumor cell proliferation and cell density in the SBRT group. Reduced demand for oxygen after SBRT (due to cell death and growth arrest from treatment) significantly contributed to reoxygenation of the pancreatic TME. Understanding how this reoxygenation phenomenon occurs in a dose-dependent manner will help improve dosing and fractionation schemes for clinical SBRT.

Development of MXene Composite Nanofiber-Based 3D Culture System for the Efficient Generation of MSC-Derived Functional Pancreatic β-Cells

Pancreatic β-cell transplantation is an effective approach for the therapeutic treatment of type I diabetes. However, it has limitations due to the lack of human cadaveric pancreas donors. Stem cells provide an alternative source for the generation of surrogate pancreatic β-cells. Nonetheless, its clinical utility is restricted due to the unavailability of a robust culture system for the generation of large quantities of insulin-responsive pancreatic β-cells. In this study, we fabricated an MXene composite nanofibrous scaffold (PCL 25_Ti2C 5 nanofiber) for the development of a three-dimensional (3D) culture system that can enhance the proliferation and differentiation of stem cell-derived pancreatic β-cells. The fabricated MXene composite nanofibers exhibited a porous nanostructure and increased hydrophilicity due to a large number of hydrophilic functional groups. We assessed the biocompatibility and differentiation potential of human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) on a fabricated MXene composite nanofibrous scaffold. MXene composite nanofibers significantly upregulated key pancreatic β-cell markers including PDX-1, MAFA, Insulin, Nkx6.1, and Nkx2.2 and also showed increased production and secretion of insulin in response to glucose stimulation when compared to control (PCL 25 nanofiber), suggesting enhanced differentiation of hWJ-MSCs into functional pancreatic β-cells. Overall, the results suggest that MXene nanofiber-based cell therapy has therapeutic potential for diabetes treatment.

Hapalindole Q suppresses autophagosome-lysosome fusion by promoting YAP1 degradation via chaperon-mediated autophagy

Autophagy is a conserved catabolic process crucial for maintaining cellular homeostasis and has emerged as a promising therapeutic target for many diseases. Mechanistically novel small-molecule autophagy regulators are highly desirable from a pharmacological point of view. Here, we report the macroautophagy-inhibitory effect of hapalindole Q, a member of the structurally intriguing but biologically understudied hapalindole family of indole terpenoids. This compound promotes the noncanonical degradation of Yes-associated protein 1 (YAP1), the downstream effector of the Hippo signaling pathway, via chaperone-mediated autophagy, disrupting proper distribution of Rab7 and suppressing autophagosome-lysosome fusion in macroautophagy. Its binding to YAP1 is further confirmed by using biophysical techniques. A preliminary structure-activity relationship study reveals that the hapalindole Q scaffold, rather than the isothiocyanate group, is essential for YAP1 binding and degradation. This work not only identifies a macroautophagy inhibitor with a distinct mechanism of action but also provided a molecular scaffold for direct targeting of YAP1, which may benefit the development of therapeutics for both autophagy-related and Hippo-YAP-related diseases.

Substrates mimicking the blastocyst geometry revert pluripotent stem cell to naivety

Naive pluripotent stem cells have the highest developmental potential but their in vivo existence in the blastocyst is transient. Here we report a blastocyst motif substrate for the in vitro reversion of mouse and human pluripotent stem cells to a naive state. The substrate features randomly varied microstructures, which we call motifs, mimicking the geometry of the blastocyst. Motifs representing mouse-blastocyst-scaled curvature ranging between 15 and 62 mm-1 were the most efficient in promoting reversion to naivety, as determined by time-resolved correlative analysis. In these substrates, apical constriction enhances E-cadherin/RAC1 signalling and activates the mechanosensitive nuclear transducer YAP, promoting the histone modification of pluripotency genes. This results in enhanced levels of pluripotency transcription factor NANOG, which persist even after cells are removed from the substrate. Pluripotent stem cells cultured in blastocyst motif substrates display a higher development potential in generating embryoid bodies and teratomas. These findings shed light on naivety-promoting substrate design and their large-scale implementation.

Liuwei Dihuang pills attenuate ovariectomy-induced bone loss by alleviating bone marrow mesenchymal stem cell (BMSC) senescence via the Yes-associated protein (YAP)-autophagy axis

CONTEXT

Liuwei Dihuang pill (LWDH) has been used to treat postmenopausal osteoporosis (PMOP).

OBJECTIVE

To explore the effects and mechanisms of action of LWDH in PMOP.

MATERIALS AND METHODS

Forty-eight female Sprague-Dawley rats were divided into four groups: sham-operated (SHAM), ovariectomized (OVX), LWDH high dose (LWDH-H, 1.6 g/kg/d) and LWDH low dose (LWDH-L, 0.8 g/kg/d); the doses were administered after ovariectomy via gavage for eight weeks. After eight weeks, the bone microarchitecture was evaluated. The effect of LWDH on the differentiation of bone marrow mesenchymal stem cells (BMSCs) was assessed via osteogenesis- and lipogenesis-induced BMSC differentiation. The senescence-related biological indices were also detected using senescence staining, cell cycle analysis, quantitative real-time polymerase chain reaction and western blotting. Finally, the expression levels of autophagy-related proteins and Yes-associated protein (YAP) were evaluated.

RESULTS

LWDH-L and LWDH-H significantly modified OVX-induced bone loss. LWDH promoted osteogenesis and inhibited adipogenesis in OVX-BMSCs. Additionally, LWDH decreased the positive ratio of senescence OVX-BMSCs and improved cell viability, cell cycle, and the mRNA and protein levels of p53 and p21. LWDH upregulated the expression of autophagy-related proteins, LC3, Beclin1 and YAP, in OVX-BMSCs and downregulated the expression of p62.

DISCUSSION AND CONCLUSIONS

LWDH improves osteoporosis by delaying the BMSC senescence through the YAP-autophagy axis.

Force-sensing protein expression in response to cardiovascular mechanotransduction

Force-sensing biophysical cues in microenvironment, including extracellular matrix performances, stretch-mediated mechanics, shear stress and flow-induced hemodynamics, have a significant influence in regulating vascular morphogenesis and cardiac remodeling by mechanotransduction. Once cells perceive these extracellular mechanical stimuli, Piezo activation promotes calcium influx by forming integrin-adhesion-coupling receptors. This induces robust contractility of cytoskeleton structures to further transmit biomechanical alternations into nuclei by regulating Hippo-Yes associated protein (YAP) signaling pathway between cytoplasmic and nuclear translocation. Although biomechanical stimuli are widely studied in cardiovascular diseases, the expression of force-sensing proteins in response to cardiovascular mechanotransduction has not been systematically concluded. Therefore, this review will summarize the force-sensing Piezo, cytoskeleton and YAP proteins to mediate extracellular mechanics, and also give the prominent emphasis on intrinsic connection of these mechanical proteins and cardiovascular mechanotransduction. Extensive insights into cardiovascular mechanics may provide some new strategies for cardiovascular clinical therapy.

A quantitative study of the effects of a dual layer coating drug-eluting stent on safety and efficacy

A key strategy for increasing drug mass (DM) while maintaining good safety is to improve the drug release profile (RP). We designed a dual layer coating drug-eluting stent (DES) that exhibited smaller concentration gradients between the coating and the artery wall and significantly impacted the drug RP. However, a detailed understanding of the effects of the DES designed by our team on safety and efficacy is still lacking. The objective of this study was to provide a comprehensive multiscale computational framework that would allow us to probe the safety and efficacy of the DES we designed. This framework consisted of four coupled modules, namely (1) a mechanical stimuli module, simulating mechanical stimuli caused by percutaneous coronary intervention through a finite element analysis, (2) an inflammation module, simulating inflammation of vascular smooth muscle cells (VSMCs) induced by mechanical stimuli through an agent-based model (ABM), (3) a drug transport module, simulating drug transport through a continuum-based approach, and (4) a mitosis module, simulating VSMC mitosis through an ABM. Our results indicated that when the DM increased to two times the initial DM value, the DES we designed had higher safety and lower efficacy values than a conventional DES. When the DM increased to five times the initial DM value, the DES we designed had higher safety than a conventional DES, and negligible differences in efficacy compared with a conventional DES. In summary, the DES we designed exhibited a significant advantage in safety, but a slightly reduced efficacy compared with that of a conventional DES.

Non-animal derived recombinant collagen-based biomaterials as a promising strategy towards adipose tissue engineering

Adipose tissue engineering (ATE) has been gaining increasing interest over the past decades, offering promise for new and innovative breast reconstructive strategies. Animal-derived gelatin-methacryloyl (Gel-MA) has already been applied in a plethora of TE strategies. However, due to clinical concerns, related to the potential occurrence of immunoglobulin E-mediated immune responses and pathogen transmission, a shift towards defined, reproducible recombinant proteins has occurred. In the present study, a recombinant protein based on human collagen type I, enriched with arginine-glycine-aspartic acid was functionalized with photo-crosslinkable methacryloyl moieties (RCPhC1-MA), processed into 3D scaffolds and compared with frequently applied Gel-MA from animal origin using an indirect printing method applying poly-lactic acid as sacrificial mould. For both materials, similar gel fractions (>65%) and biodegradation times were obtained. In addition, a significantly lower mass swelling ratio (17.6 ± 1.5 versus 24.3 ± 1.4) and mechanical strength (Young's modulus: 1.1 ± 0.2 kPa versus 1.9 ± 0.3 kPa) were observed for RCPhC1-MA compared to Gel-MA scaffolds.In vitroseeding assays showed similar cell viabilities (>80%) and a higher initial cell attachment for the RCPhC1-MA scaffolds. Moreover, the seeded adipose-derived stem cells could be differentiated into the adipogenic lineage for both Gel-MA and RCPhC1-MA scaffolds, showing a trend towards superior differentiation for the RCPhC1-MA scaffolds based on the triglyceride and Bodipy assay. RCPhC1-MA scaffolds could result in a transition towards the exploitation of non-animal-derived biomaterials for ATE, omitting any regulatory concerns related to the use of animal derived products.

Cellular Architects at Work: Cells Building their Own Microgel Houses

Microporous annealed particle (MAP) scaffolds are investigated for their application as injectable 3D constructs in the field of regenerative medicine and tissue repair. While available MAP scaffolds provide a stable interlinked matrix of microgels for cell culture, the infiltration depth and space for cells to grow inside the scaffolds is pre-determined by the void fraction during the assembly. In the case of MAP scaffolds fabricated from interlinked spherical microgels, a cellularity gradient can be observed with the highest cell density on the scaffold surface. Additionally, the interlinked microgel network limits the ability of cells to remodel their environment, which contradicts native tissue dynamics. In this work, a cell-induced interlinking method for MAP scaffold formation is established, which avoids the necessity of chemical crosslinkers and pre-engineered pores to achieve micro- or macropores in these 3D frameworks. This method enables cells to self-organize with microgels into dynamic tissue constructs, which can be further controlled by altering the microgel properties, the cell/microgel ratio, and well shape. To form a cell-induced interlinked scaffold, the cells are mixed with dextran-based microgels and function as a glue between the microgels, resulting in a more homogenous cell distribution throughout the scaffold with efficient cell-cell interactions.

Eukaryotic cell size regulation and its implications for cellular function and dysfunction

Depending on cell type, environmental inputs, and disease, the cells in the human body can have widely different sizes. In recent years, it has become clear that cell size is a major regulator of cell function. However, we are only beginning to understand how the optimization of cell function determines a given cell's optimal size. Here, we review currently known size control strategies of eukaryotic cells and the intricate link of cell size to intracellular biomolecular scaling, organelle homeostasis, and cell cycle progression. We detail the cell size-dependent regulation of early development and the impact of cell size on cell differentiation. Given the importance of cell size for normal cellular physiology, cell size control must account for changing environmental conditions. We describe how cells sense environmental stimuli, such as nutrient availability, and accordingly adapt their size by regulating cell growth and cell cycle progression. Moreover, we discuss the correlation of pathological states with misregulation of cell size and how for a long time this was considered a downstream consequence of cellular dysfunction. We review newer studies that reveal a reversed causality, with misregulated cell size leading to pathophysiological phenotypes such as senescence and aging. In summary, we highlight the important roles of cell size in cellular function and dysfunction, which could have major implications for both diagnostics and treatment in the clinic.

ContactBlot: Microfluidic Control and Measurement of the Cell-Cell Contact State to Assess Contact-Inhibited ERK Signaling

Extracellular signal-regulated kinase (ERK) signaling is essential to regulated cell behaviors, including cell proliferation, differentiation, and apoptosis. The influence of cell-cell contacts on ERK signaling is central to epithelial cells, yet few studies have sought to understand the same in cancer cells, particularly with single-cell resolution. To acquire same-cell measurements of both phenotypic (cell-contact state) and targeted-protein (ERK phosphorylation) profiles, we prepend high-content, whole-cell imaging prior to end-point cellular-resolution Western blot analyses for each of hundreds of individual HeLa cancer cells cultured on that same chip, which we call contactBlot. By indexing the phosphorylation level of ERK in each cell or cell cluster to the imaged cell-contact state, we compare the ERK signaling between isolated and in-contact cells. We observe attenuated (∼2×) ERK signaling in HeLa cells that are in-contact versus isolated. Attenuation is sustained when the HeLa cells are challenged with hyperosmotic stress. Our findings show the impact of cell-cell contacts on ERK activation with isolated and in-contact cells while introducing a multi-omics tool for control and scrutiny of cell-cell interactions.

Prostate Cancer's Silent Partners: Fibroblasts and Their Influence on Glutamine Metabolism Manipulation

Cancer-associated fibroblast (CAF)s in the tumour microenvironment (TME) modulate the extracellular matrix, interact with cancer cells, and facilitate communication with infiltrating leukocytes, significantly contributing to cancer progression and therapeutic response. In prostate cancer (PCa), CAFs promote malignancy through metabolic rewiring, cancer stem cell regulation, and therapy resistance. Pre-clinical studies indicate that targeting amino acid metabolism, particularly glutamine (Gln) metabolism, reduces cancer proliferation and stemness. However, most studies lack the context of CAF-cancer interaction, focusing on monocultures. This study assesses the influence of CAFs on PCa growth by manipulating Gln metabolism using colour-labelled PCa cell lines (red) and fibroblast (green) in a co-culture system to evaluate CAFs' effects on PCa cell proliferation and clonogenic potential. CAFs increased the proliferation of hormone-sensitive LNCaP cells, whereas the castration-resistant C4-2 cells were unaffected. However, clonogenic growth increased in both cell lines. Gln deprivation and GLS1 inhibition experiments revealed that the increased growth rate of LNCAP cells was associated with increased dependence on Gln, which was confirmed by proteomic analyses. Tissue analysis of PCa patients revealed elevated GLS1 levels in both the PCa epithelium and stroma, suggesting that GLS1 is a therapeutic target. Moreover, the median overall survival analysis of GLS1 expression in the PCa epithelium and stroma identified a "high-risk" patient group that may benefit from GLS1-targeted therapies. Therefore, GLS1 targeting appears promising in castration-resistant PCa patients with high GLS1 epithelium and low GLS1 stromal expression.

From stress fiber to focal adhesion: a role of actin crosslinkers in force transmission

The contractile apparatus, stress fiber (SF), is connected to the cell adhesion machinery, focal adhesion (FA), at the termini of SF. The SF-FA complex is essential for various mechanical activities of cells, including cell adhesion to the extracellular matrix (ECM), ECM rigidity sensing, and cell migration. This mini-review highlights the importance of SF mechanics in these cellular activities. Actin-crosslinking proteins solidify SFs by attenuating myosin-driven flows of actin and myosin filaments within the SF. In the solidified SFs, viscous slippage between actin filaments in SFs and between the filaments and the surrounding cytosol is reduced, leading to efficient transmission of myosin-generated contractile force along the SFs. Hence, SF solidification via actin crosslinking ensures exertion of a large force to FAs, enabling FA maturation, ECM rigidity sensing and cell migration. We further discuss intracellular mechanisms for tuning crosslinker-modulated SF mechanics and the potential relationship between the aberrance of SF mechanics and pathology including cancer.

Hyperglycemia Stimulates the Irreversible Catabolism of Branched-Chain Amino Acids and Generation of Ketone Bodies by Cultured Human Astrocytes

Astrocytes are considered to possess a noticeable role in brain metabolism and, as a partners in neuron-glia cooperation, to contribute to the synthesis, bioconversion, and regulation of the flux of substrates for neuronal metabolism. With the aim of investigating to what extent human astrocytes are metabolizing amino acids and by which compounds are they enriching their surroundings, we employed a metabolomics analysis of their culture media by 1H-NMR. In addition, we compared the composition of media with either 5 mM or 25 mM glucose. The quantitative analysis of culture media by 1H-NMR revealed that astrocytes readily dispose from their milieu glutamine, branched-chain amino acids, and pyruvate with significantly high rates, while they enrich the culture media with lactate, branched-chain keto acids, citrate, acetate, ketone bodies, and alanine. Hyperglycemia suppressed the capacity of astrocytes to release branched-chain 2-oxo acids, while stimulating the generation of ketone bodies. Our results highlight the active involvement of astrocytes in the metabolism of several amino acids and the regulation of key metabolic intermediates. The observed metabolic activities of astrocytes provide valuable insights into their roles in supporting neuronal function, brain metabolism, and intercellular metabolic interactions within the brain. Understanding the complex metabolic interactions between astrocytes and neurons is essential for elucidating brain homeostasis and the pathophysiology of neurological disorders. The observed metabolic activities of astrocytes provide hints about their putative metabolic roles in brain metabolism.

Characterization of Iron Oxide Nanotubes Obtained by Anodic Oxidation for Biomedical Applications-In Vitro Studies

To improve the biocompatibility and bioactivity of biodegradable iron-based materials, nanostructured surfaces formed by metal oxides offer a promising strategy for surface functionalization. To explore this potential, iron oxide nanotubes were synthesized on pure iron (Fe) using an anodic oxidation process (50 V-30 min, using an ethylene glycol solution containing 0.3% NH4F and 3% H2O, at a speed of 100 rpm). A nanotube layer composed mainly of α-Fe2O3 with diameters between 60 and 70 nm was obtained. The effect of the Fe-oxide nanotube layer on cell viability and morphology was evaluated by in vitro studies using a human osteosarcoma cell line (SaOs-2 cells). The results showed that the presence of this layer did not harm the viability or morphology of the cells. Furthermore, cells cultured on anodized surfaces showed higher metabolic activity than those on non-anodized surfaces. This research suggests that growing a layer of Fe oxide nanotubes on pure Fe is a promising method for functionalizing and improving the cytocompatibility of iron substrates. This opens up new opportunities for biomedical applications, including the development of cardiovascular stents or osteosynthesis implants.

Adipogenic differentiation effect of human periodontal ligament stem cell initial cell density on autologous cells and human bone marrow stromal cells

Stem cells demonstrate differentiation and regulatory functions. In this discussion, we will explore the impacts of cell culture density on stem cell proliferation, adipogenesis, and regulatory abilities. This study aimed to investigate the impact of the initial culture density of human periodontal ligament stem cells (hPDLSCs) on the adipogenic differentiation of autologous cells. Our findings indicate that the proliferation rate of hPDLSCs increased with increasing initial cell density (0.5-8 × 104 cells/cm2). After adipogenic differentiation induced by different initial cell densities of hPDLSC, we found that the mean adipose concentration and the expression levels of lipoprotein lipase (LPL), CCAAT/enhancer binding protein α (CEBPα), and peroxisome proliferator-activated receptor γ (PPAR-γ) genes all increased with increasing cell density. To investigate the regulatory role of hPDLSCs in the adipogenic differentiation of other cells, we used secreted exocrine vesicles derived from hPDLSCs cultivated at different initial cell densities of 50 μg/mL to induce the adipogenic differentiation of human bone marrow stromal cells. We also found that the mean adipose concentration and expression of LPL, CEBPα, and PPARγ genes increased with increasing cell density, with an optimal culture density of 8 × 104 cells/cm2. This study provides a foundation for the application of adipogenic differentiation in stem cells.

Halogenated Boroxine K2[B3O3F4OH] Modulates Metabolic Phenotype and Autophagy in Human Bladder Carcinoma 5637 Cell Line

Halogenated boroxine K2[B3O3F4OH] (HB), an inorganic derivative of cyclic anhydride of boronic acid, is patented as a boron-containing compound with potential for the treatment of both benign and malignant skin changes. HB has effectively inhibited the growth of several carcinoma cell lines. Because of the growing interest in autophagy induction as a therapeutic approach in bladder carcinoma (BC), we aimed to assess the effects of HB on metabolic phenotype and autophagy levels in 5637 human bladder carcinoma cells (BC). Cytotoxicity was evaluated using the alamar blue assay, and the degree of autophagy was determined microscopically. Mitochondrial respiration and glycolysis were measured simultaneously. The relative expression of autophagy-related genes BECN1, P62, BCL-2, and DRAM1 was determined by real-time PCR. HB affected cell growth, while starvation significantly increased the level of autophagy in the positive control compared to the basal level of autophagy in the untreated negative control. In HB-treated cultures, the degree of autophagy was higher compared to the basal level, and metabolic phenotypes were altered; both glycolysis and oxidative phosphorylation (OXPHOS) were decreased by HB at 0.2 and 0.4 mg/mL. Gene expression was deregulated towards autophagy induction and expansion. In conclusion, HB disrupted the bioenergetic metabolism and reduced the intracellular survival potential of BC cells. Further molecular studies are needed to confirm these findings and investigate their applicative potential.

Contact Blot: Microfluidic Control and Measurement of Cell-Cell Contact State to Assess Contact-Inhibited ERK Signaling

Extracellular signal-regulated kinase (ERK) signaling is essential to regulated cell behaviors, including cell proliferation, differentiation, and apoptosis. The influence of cell-cell contacts on ERK signaling is central to epithelial cells, yet few studies have sought to understand the same in cancer cells, particularly with single-cell resolution. To acquire same-cell measurements of both phenotypic (cell-contact state) and targeted-protein profile (ERK phosphorylation), we prepend high-content, whole-cell imaging prior to endpoint cellular-resolution western blot analyses for each of hundreds of individual HeLa cancer cells cultured on that same chip, which we call contact Blot. By indexing the phosphorylation level of ERK in each cell or cell-cluster to the imaged cell-contact state, we compare ERK signaling between isolated and in-contact cells. We observe attenuated (~2×) ERK signaling in HeLa cells which are in-contact versus isolated. Attenuation is sustained when the HeLa cells are challenged with hyperosmotic stress. Our findings show the impact of cell-cell contacts on ERK activation with isolated and in-contact cells, while introducing a multi omics tool for control and scrutiny of cell-cell interactions.

Semisynthesis and biological evaluation of novel honokiol thioethers against colon cancer cells HCT116 via inhibiting the transcription and expression of YAP protein

Honokiol, derived from Magnolia officinalis (a traditional Chinese medicine), has been reported to have anticancer activity. Here, a series of novel honokiol thioethers bearing a 1,3,4-oxadiazole moiety were prepared and evaluated for their anticancer activities against three types of digestive system tumor cells. Biological evaluation showed that honokiol derivative 3k exhibited the best antiproliferative activity against HCT116 cells with an IC50 value of 6.1 μmol/L, superior to the reference drug 5-fluorouracil (IC50: 9.63 ± 0.27 µmol/L). The structure-activity relationships (SARs) indicated that the introduction of -(4-NO2)Ph, 3-pyridyl, -(2-F)Ph, -(4-F)Ph, -(3-F)Ph, -(4-Cl)Ph, and -(3-Cl)Ph groups was favorable for enhancing the anticancer activity of the title honokiol thioethers. Further study revealed that honokiol thioether 3k can well inhibit the proliferation of colon cancer cells HCT116, arresting the cells in G1 phase and inducing cell death. Moreover, a preliminary mechanism study indicated that 3k directly inhibits the transcription and expression of YAP protein without activating the Hippo signaling pathway. Thus, honokiol thioether 3k could be deeply developed for the development of honokiol-based anticancer candidates.

The molecular determinants of microglial developmental dynamics

Microglia constitute the largest population of parenchymal macrophages in the brain and are considered a unique subset of central nervous system glial cells owing to their extra-embryonic origins in the yolk sac. During development, microglial progenitors readily proliferate and eventually colonize the entire brain. In this Review, we highlight the origins of microglial progenitors and their entry routes into the brain and discuss the various molecular and non-molecular determinants of their fate, which may inform their specific functions. Specifically, we explore recently identified mechanisms that regulate microglial colonization of the brain, including the availability of space, and describe how the expansion of highly proliferative microglial progenitors facilitates the occupation of the microglial niche. Finally, we shed light on the factors involved in establishing microglial identity in the brain.

Spheroids Generated from Malignant Pleural Effusion as a Tool to Predict the Response of Non-Small Cell Lung Cancer to Treatment

BACKGROUND

Spheroids generated by tumor cells collected from malignant pleural effusion (MPE) were shown to retain the characteristics of the original tumors. This ex vivo model might be used to predict the response of non-small cell lung cancer (NSCLC) to anticancer treatments.

METHODS

The characteristics, epidermal growth factor receptor (EGFR) mutation status, and clinical response to EGFR-TKIs treatment of enrolled patients were recorded. The viability of the spheroids generated from MPE of enrolled patients were evaluated by visualization of the formazan product of the MTT assay.

RESULTS

Spheroids were generated from 14 patients with NSCLC-related MPE. Patients with EGFR L861Q, L858R, or Exon 19 deletion all received EGFR-TKIs, and five of these seven patients responded to treatment. The viability of the spheroids generated from MPE of these five patients who responded to EGFR-TKIs treatment was significantly reduced after gefitinib treatment. On the other hand, gefitinib treatment did not reduce the viability of the spheroids generated from MPE of patients with EGFR wild type, Exon 20 insertion, or patients with sensitive EGFR mutation but did not respond to EGFR-TKIs treatment.

CONCLUSION

Multicellular spheroids generated from NSCLC-related MPE might be used to predict the response of NSCLC to treatment.

The roles of Hippo/YAP signaling pathway in physical therapy

Cellular behavior is regulated by mechanical signals within the cellular microenvironment. Additionally, changes of temperature, blood flow, and muscle contraction also affect cellular state and the development of diseases. In clinical practice, physical therapy techniques such as ultrasound, vibration, exercise, cold therapy, and hyperthermia are commonly employed to alleviate pain and treat diseases. However, the molecular mechanism about how these physiotherapy methods stimulate local tissues and control gene expression remains unknow. Fortunately, the discovery of YAP filled this gap, which has been reported has the ability to sense and convert a wide variety of mechanical signals into cell-specific programs for transcription, thereby offering a fresh perspective on the mechanisms by which physiotherapy treat different diseases. This review examines the involvement of Hippo/YAP signaling pathway in various diseases and its role in different physical therapy approaches on diseases. Furthermore, we explore the potential therapeutic implications of the Hippo/YAP signaling pathway and address the limitations and controversies surrounding its application in physiotherapy.

TAZ deficiency impairs the autophagy-lysosomal pathway through NRF2 dysregulation and lysosomal dysfunction

Transcriptional coactivator with a PDZ-binding motif (TAZ) plays a key role in normal tissue homeostasis and tumorigenesis through interaction with several transcription factors. In particular, TAZ deficiency causes abnormal alveolarization and emphysema, and persistent TAZ overexpression contributes to lung cancer and pulmonary fibrosis, suggesting the possibility of a complex mechanism of TAZ function. Recent studies suggest that nuclear factor erythroid 2-related factor 2 (NRF2), an antioxidant defense system, induces TAZ expression during tumorigenesis and that TAZ also activates the NRF2-mediated antioxidant pathway. We thus thought to elucidate the cross-regulation of TAZ and NRF2 and the underlying molecular mechanisms and functions. TAZ directly interacted with NRF2 through the N-terminal domain and suppressed the transcriptional activity of NRF2 by preventing NRF2 from binding to DNA. In addition, the return of NRF2 to basal levels after signaling was inhibited in TAZ deficiency, resulting in sustained nuclear NRF2 levels and aberrantly increased expression of NRF2 targets. TAZ deficiency failed to modulate optimal NRF2 signaling and concomitantly impaired lysosomal acidification and lysosomal enzyme function, accumulating the abnormal autophagy vesicles and reactive oxygen species and causing protein oxidation and cellular damage in the lungs. TAZ restoration to TAZ deficiency normalized dysregulated NRF2 signaling and aberrant lysosomal function and triggered the normal autophagy-lysosomal pathway. Therefore, TAZ is indispensable for the optimal regulation of NRF2-mediated autophagy-lysosomal pathways and for preventing pulmonary damage caused by oxidative stress and oxidized proteins.

Acoustic levitation as a tool for cell-driven self-organization of human cell spheroids during long-term 3D culture

Acoustic levitation, which allows contactless manipulation of micro-objects with ultrasounds, is a promising technique for spheroids formation and culture. This acoustofluidic technique favors cell-cell interactions, away from the walls of the chip, which leads to the spontaneous self-organization of cells. Using this approach, we generated spheroids of mesenchymal stromal cells, hepatic and endothelial cells, and showed that long-term culture of cells in acoustic levitation is feasible. We also demonstrated that this self-organization and its dynamics depended weakly on the acoustic parameters but were strongly dependent on the levitated cell type. Moreover, spheroid organization was modified by actin cytoskeleton inhibitors or calcium-mediated interaction inhibitors. Our results confirmed that acoustic levitation is a rising technique for fundamental research and biotechnological industrial application in the rapidly growing field of microphysiological systems. It allowed easily obtaining spheroids of specific and predictable shape and size, which could be cultivated over several days, without requiring hydrogels or extracellular matrix.

Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells

BACKGROUND

The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years, which also may lead to some complications such as alveolar bone resorption or tooth root resorption. Low-intensity pulsed ultrasound (LIPUS), a noninvasive physical therapy, has been shown to promote bone fracture healing. It is also reported that LIPUS could reduce the duration of orthodontic treatment; however, how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear.

AIM

To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement (OTM) model and explore the underlying mechanisms.

METHODS

A rat model of OTM was established, and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections. In vitro, human bone marrow mesenchymal stem cells (hBMSCs) were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction, Western blot, alkaline phosphatase (ALP) staining, and Alizarin red staining. The expression of Yes-associated protein (YAP1), the actin cytoskeleton, and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA (siRNA) application via immunofluorescence.

RESULTS

The force treatment inhibited the osteogenic differentiation potential of hBMSCs; moreover, the expression of osteogenesis markers, such as type 1 collagen (COL1), runt-related transcription factor 2, ALP, and osteocalcin (OCN), decreased. LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force. Mechanically, the expression of LaminA/C, F-actin, and YAP1 was downregulated after force treatment, which could be rescued by LIPUS. Moreover, the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment. Consistently, LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo. The decreased expression of COL1, OCN, and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS.

CONCLUSION

LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis, which may be a promising strategy to reduce the orthodontic treatment process.

Hippo (YAP)-autophagy axis protects against hepatic ischemia-reperfusion injury through JNK signaling

BACKGROUND

Hepatic ischemia-reperfusion injury (HIRI) remains a common complication during liver transplantation (LT) in patients. As a key downstream effector of the Hippo pathway, Yes-associated protein (YAP) has been reported to be involved in various physiological and pathological processes. However, it remains elusive whether and how YAP may control autophagy activation during ischemia-reperfusion.

METHODS

Human liver tissues from patients who had undergone LT were obtained to evaluate the correlation between YAP and autophagy activation. Both an in vitro hepatocyte cell line and in vivo liver-specific YAP knockdown mice were used to establish the hepatic ischemia-reperfusion models to determine the role of YAP in the activation of autophagy and the mechanism of regulation.

RESULTS

Autophagy was activated in the post-perfusion liver grafts during LT in patients, and the expression of YAP positively correlated with the autophagic level of hepatocytes. Liver-specific knockdown of YAP inhibited hepatocytes autophagy upon hypoxia-reoxygenation and HIRI ( P <0.05). YAP deficiency aggravated HIRI by promoting the apoptosis of hepatocytes both in the in vitro and in vivo models ( P <0.05). Attenuated HIRI by overexpression of YAP was diminished after the inhibition of autophagy with 3-methyladenine. In addition, inhibiting autophagy activation by YAP knockdown exacerbated mitochondrial damage through increasing reactive oxygen species ( P <0.05). Moreover, the regulation of autophagy by YAP during HIRI was mediated by AP1 (c-Jun) N-terminal kinase (JNK) signaling through binding to the transcriptional enhanced associate domain (TEAD).

CONCLUSIONS

YAP protects against HIRI by inducing autophagy via JNK signaling that suppresses the apoptosis of hepatocytes. Targeting Hippo (YAP)-JNK-autophagy axis may provide a novel strategy for the prevention and treatment of HIRI.

Merlin/NF2 regulates SLC7A11/xCT expression and cell viability under glucose deprivation at high cell density in glioblastoma cells

The cystine/glutamate transporter SLC7A11/xCT is highly expressed in many cancer cells and plays an important role in antioxidant activity by supplying cysteine for glutathione synthesis. Under glucose-depleted conditions, however, SLC7A11-mediated cystine uptake causes oxidative stress and cell death called disulfidptosis, a new form of cell death. We previously reported that high cell density (HD) promotes lysosomal degradation of SLC7A11 in glioblastoma cells, allowing them to survive under glucose-depleted conditions. In this study, we found that the neurofibromatosis type 2 gene, Merlin/NF2 is a key regulator of SLC7A11 in glioblastoma cells at HD. Deletion of Merlin increased SLC7A11 protein level and cystine uptake at HD, leading to promotion of cell death under glucose deprivation. Furthermore, HD significantly decreased SLC7A11 mRNA level, which was restored by Merlin deletion. This study suggests that Merlin suppresses glucose deprivation-induced cell death by downregulating SLC7A11 expression in glioblastoma cells at HD.

RGS20 promotes non-small cell lung carcinoma proliferation via autophagy activation and inhibition of the PKA-Hippo signaling pathway

BACKGROUND

Novel therapeutic targets are urgently needed for treating drug-resistant non-small cell lung cancer (NSCLC) and overcoming drug resistance to molecular-targeted therapies. Regulator of G protein signaling 20 (RGS20) is identified as an upregulated factor in many cancers, yet its specific role and the mechanism through which RGS20 functions in NSCLC remain unclear. Our study aimed to identify the role of RGS20 in NSCLC prognosis and delineate associated cellular and molecular pathways.

METHODS

Immunohistochemistry and lung cancer tissue microarray were used to verify the expression of RGS20 between NSCLC patients. CCK8 and cell cloning were conducted to determine the proliferation ability of H1299 and Anip973 cells in vitro. Furthermore, Transcriptome sequencing was performed to show enrichment genes and pathways. Immunofluorescence was used to detect the translocation changes of YAP to nucleus. Western blotting demonstrated different expressions of autophagy and the Hippo-PKA signal pathway. In vitro and in vivo experiments verified whether overexpression of RGS20 affect the proliferation and autophagy of NSCLC through regulating the Hippo pathway.

RESULTS

The higher RGS20 expression was found to be significantly correlated with a poorer five-year survival rate. Further, RGS20 accelerated cell proliferation by increasing autophagy. Transcriptomic sequencing suggested the involvement of the Hippo signaling pathway in the action of RGS20 in NSCLC. RGS20 activation reduced YAP phosphorylation and facilitated its nuclear translocation. Remarkably, inhibiting Hippo signaling with GA-017 promoted cell proliferation and activated autophagy in RGS20 knock-down cells. However, forskolin, a GPCR activator, increased YAP phosphorylation and reversed the promoting effect of RGS20 in RGS20-overexpressing cells. Lastly, in vivo experiments further confirmed role of RGS20 in aggravating tumorigenicity, as its overexpression increased NSCLC cell proliferation.

CONCLUSION

Our findings indicate that RGS20 drives NSCLC cell proliferation by triggering autophagy via the inhibition of PKA-Hippo signaling. These insights support the role of RGS20 as a promising novel molecular marker and a target for future targeted therapies in lung cancer treatment.

The Role of Mechanotransduction in Contact Inhibition of Locomotion and Proliferation

Contact inhibition (CI) represents a crucial tumor-suppressive mechanism responsible for controlling the unbridled growth of cells, thus preventing the formation of cancerous tissues. CI can be further categorized into two distinct yet interrelated components: CI of locomotion (CIL) and CI of proliferation (CIP). These two components of CI have historically been viewed as separate processes, but emerging research suggests that they may be regulated by both distinct and shared pathways. Specifically, recent studies have indicated that both CIP and CIL utilize mechanotransduction pathways, a process that involves cells sensing and responding to mechanical forces. This review article describes the role of mechanotransduction in CI, shedding light on how mechanical forces regulate CIL and CIP. Emphasis is placed on filamin A (FLNA)-mediated mechanotransduction, elucidating how FLNA senses mechanical forces and translates them into crucial biochemical signals that regulate cell locomotion and proliferation. In addition to FLNA, trans-acting factors (TAFs), which are proteins or regulatory RNAs capable of directly or indirectly binding to specific DNA sequences in distant genes to regulate gene expression, emerge as sensitive players in both the mechanotransduction and signaling pathways of CI. This article presents methods for identifying these TAF proteins and profiling the associated changes in chromatin structure, offering valuable insights into CI and other biological functions mediated by mechanotransduction. Finally, it addresses unanswered research questions in these fields and delineates their possible future directions.

Carbon quantum dot-nanocomposite hydrogel as Denovo Nexus in rapid chondrogenesis

The incapability of cartilage to naturally regenerate and repair chronic muscular injuries urges the development of competent bionic rostrums. There is a need to explore faster strategies for chondrogenic engineering using mesenchymal stem cells (MSCs). Along these lines, rapid chondrocyte differentiation would benefit the transplantation demand affecting osteoarthritis (OA) and rheumatoid arthritis (RA) patients. In this report, a de novo nanocomposite was constructed by integrating biogenic carbon quantum dot (CQD) filler into synthetic hydrogel prepared from dimethylaminoethyl methacrylate (DMAEMA) and acrylic acid (AAc). The dominant structural integrity of synthetic hydrogel along with the chondrogenic differentiation potential of garlic peel derived CQDs led to faster chondrogenesis within 14 days. By means of extensive chemical and morphological characterization techniques, we illustrate that the hydrogel nanocomposite possesses lucrative features to influence rapid chondrogenesis. These results were further corroborated by bright field imaging, Alcian blue staining and Masson trichome staining. Thus, this stratagem of chondrogenic engineering conceptualizes to be a paragon in clinical wound care for the rapid manufacturing of chondrocytes.

Erdr1 Drives Macrophage Programming via Dynamic Interplay with YAP1 and Mid1

Erythroid differentiation regulator 1 (Erdr1) is a stress-induced, widely expressed, highly conserved secreted factor found in both humans and mice. Erdr1 is linked with the Hippo-YAP1 signaling. Initially identified as an inducer of hemoglobin synthesis, Erdr1 emerged as a multifunctional protein, especially in immune cells. Although Erdr1 has been implicated in regulating T cells and NK cell function, its role in macrophage remains unclear. This study explored the function and mechanism of Erdr1 in macrophage inflammatory response. The data demonstrated that Erdr1 could promote anti-inflammatory cytokine production, a function that also has been reported by previous research. However, I found Erdr1 also could play a proinflammatory role. The function of Erdr1 in macrophages depends on its dose and cell density. I observed that Erdr1 expression was inhibited in M1 macrophages but was upregulated in M2 macrophages compared with unpolarized macrophages. I hypothesized that Erdr1 balances the inflammatory response by binding with distinct adaptors dependent on varying concentrations. Mechanistically, I demonstrated YAP1 and Mid1 as the two adaptor proteins of Erdr1. The Erdr1-YAP1 interaction promotes anti-inflammatory cytokine production when Erdr1 levels are elevated, whereas the Erdr1-Mid1 interaction induces proinflammatory cytokine production when Erdr1 levels are decreased. This study highlights the effects of Erdr1 on regulating cytokine production from polarized macrophages potentially by regulating YAP1 in the nonclassical Hippo pathway.

Nobiletin Alleviated Epithelial-Mesenchymal Transition of Hepatocytes in Liver Fibrosis Based on Autophagy-Hippo/YAP Pathway

SCOPE

The current researches indicated that the epithelial-mesenchymal transition (EMT) of hepatocytes plays a crucial role in the development of liver fibrosis. To date, there is a paucity of literature regarding the impact of nobiletin (NOB) on liver fibrosis. This study investigates the inhibitory effect of NOB on EMT in hepatocytes during the progression of liver fibrosis and its underlying mechanism.

METHODS AND RESULTS

The findings demonstrated that NOB significantly suppresses liver fibrosis in carbon tetrachloride (CCl4 )-induced mice by reducing inflammation and fiber deposition in the liver. Moreover, NOB mitigates EMT in hepatocytes, concurrently alleviating inflammatory status and reducing the production of reactive oxygen species (ROS) generation. The comprehensive investigation reveals that the hepatoprotective effect of NOB in liver fibrosis is attributed to autophagy activation, as evidenced by a significant increase in LC3 II expression and p62 degradation upon NOB treatment. Additionally, NOB activates the Hippo/YAP pathway by downregulating YAP and its downstream targets in liver fibrosis, which is regulated by autophagy based on experiments with chloroquine (CQ), 3-methyladenine (3-MA), and siYAP intervention.

CONCLUSION

Therefore, this study provides evidences that NOB can protect hepatocytes from undergoing EMT during liver fibrosis by inducing autophagy and subsequently modulating the Hippo/YAP pathway.

Expression and role of FKBPL in lung adenocarcinoma

Dysregulated expression of FK506-binding protein like (FKBPL) has been demonstrated to play crucial roles in tumour development. However, the role of FKBPL in lung adenocarcinoma (ADC) remains unclear. Using immunohistochemical staining, we showed that FKBPL expression was significantly lower in lung ADC than the normal tissues (P < 0.0001). Patients with well or moderately differentiated tumours have higher FKBPL expression compared with patients with poor differentiated tumours (P = 0.037). However, no significant associations were found between FKBPL expression and other clinicopathological variables (P > 0.05 for all). Cox univariate analysis showed that high FKBPL expression was correlated with prolonged overall survival (OS) (P = 0.010). Kaplan-Meier analysis further confirmed that the FKBPL-low group showed a significantly shorter OS than the FKBPL-high group (P = 0.0081). FKBPL expression was not shown as an independent prognostic factor for OS in the multivariate analysis (P = 0.063). Moreover, our study demonstrated that FKBPL could suppress the proliferation of lung ADC cells by delaying cell cycle G1/S phase transition. In addition, FKBPL resulted in increased apoptosis in lung ADC cells. Using the Human Apoptosis Array Kit, we observed that overexpression of FKBPL in lung ADC A549 cells significantly decreased the anti-apoptotic proteins, including heat shock protein 32 (HSP32), heat shock protein 27 (HSP27), and paraoxonase-2 (PON2). FKBPL depletion significantly attenuated the pro-apoptotic protein, phospho-p53 (S46), in lung ADC H1975 cells. These new findings provide an experimental basis for further theoretical investigation of lung ADC.

The Function of Autophagy in the Initiation, and Development of Breast Cancer

Autophagy is a significant catabolic procedure that increases in stressful conditions. This mechanism is mostly triggered after damage to the organelles, the presence of unnatural proteins, and nutrient recycling in reaction to these stresses. One of the key points in this article is that cleaning and preserving damaged organelles and accumulated molecules through autophagy in normal cells helps prevent cancer. Since dysfunction of autophagy is associated with various diseases, including cancer, it has a dual function in tumor suppression and expansion. It has newly become clear that the regulation of autophagy can be used for the treatment of breast cancer, which has a promising effect of increasing the efficiency of anticancer treatment in a tissue- and cell-type-specific manner by affecting the fundamental molecular mechanisms. Regulation of autophagy and its function in tumorigenesis is a vital part of modern anticancer techniques. This study discusses the current advances related to the mechanisms that describe essential modulators of autophagy involved in the metastasis of cancers and the development of new breast cancer treatments.