The Cytoskeleton-A Complex Interacting Meshwork

Antibody-drug conjugates for targeted cancer therapy: Recent advances in potential payloads

Antibody-drug conjugates (ADCs) represent a promising cancer therapy modality which specifically delivers highly toxic payloads to cancer cells through antigen-specific monoclonal antibodies (mAbs). To date, 15 ADCs have been approved and more than 100 ADC candidates have advanced to clinical trials for the treatment of various cancers. Among these ADCs, microtubule-targeting and DNA-damaging agents are at the forefront of payload development. However, several challenges including toxicity and drug resistance limit the potential of this modality. To tackle these issues, multiple innovative payloads such as immunomodulators and proteolysis targeting chimeras (PROTACs) are incorporated into ADCs to enable multimodal cancer therapy. In this review, we describe the mechanism of ADCs, highlight the importance of ADC payloads and summarize recent progresses of conventional and unconventional ADC payloads, trying to provide an insight into payload diversification as a key step in future ADC development.

Promising anti-proliferative indolic benzenesulfonamides alter mechanisms with sulfonamide nitrogen substituents

Agents that cause apoptotic cell death by interfering with tubulin dynamics, such as vinblastine and paclitaxel, are an important class of chemotherapeutics. Unfortunately, these compounds are substrates for multidrug resistance (MDR) pumps, allowing cancer cells to gain resistance to these chemotherapeutics. The indolesulfonamide family of tubulin inhibitors are not excluded by MDR pumps and have a promising activity profile, although their high lipophilicity is a pharmacokinetic limitation for their clinical use. Here we present a new family of N-indolyl-3,4,5-trimethoxybenzenesulfonamide derivatives with modifications on the indole system at positions 1 and 3 and on the sulfonamide nitrogen. We synthesized and screened against HeLa cells 34 novel indolic benzenesulfonamides. The most potent derivatives (1.7-109 nM) were tested against a broad panel of cancer cell lines, which revealed that substituted benzenesulfonamides analogs had highest potency. Importantly, these compounds were only moderately toxic to non-tumorigenic cells, suggesting the presence of a therapeutic index. Consistent with known clinical anti-tubulin agents, these compounds arrested the cell cycle at G2/M phase. Mechanistically, they induced apoptosis via caspase 3/7 activation, which occurred during M arrest. The substituents on the sulfonamide nitrogen appeared to determine different mechanistic results and cell fates. These results suggest that the compounds act differently depending on the bridge substituents, thus making them very interesting as mechanistic probes as well as potential drugs for further development.

Genome-wide identification and characterization of FORMIN gene family in potato (Solanum tuberosum L.) and their expression profiles in response to drought stress condition

Formin proteins, characterized by the FH2 domain, are critical in regulating actin-driven cellular processes and cytoskeletal dynamics during abiotic stress. However, no genome-wide analysis of the formin gene family has yet to be conducted in the economically significant plant potato (Solanum tuberosum L.). In this study, 26 formin genes were identified and characterized in the potato genome (named as StFH), each containing the typical FH2 domain and distributed across the ten chromosomes. The StFH was categorized into seven subgroups (A-G) and the gene structure and motif analysis demonstrated higher structural similarities within the subgroups. Besides, the StFH exhibited ancestry and functional similarities with Arabidopsis. The Ka/Ks ratio indicated that StFH gene pairs were evolving through purifying selection, with five gene pairs exhibiting segmental duplications and two pairs exhibiting tandem duplications. Subcellular localization analysis suggested that most of the StFH genes were located in the chloroplast and plasma membrane. Moreover, 54 cis-acting regulatory elements (CAREs) were identified in the promoter regions, some of which were associated with stress responses. According to gene ontology analysis, the majority of the StFH genes were involved in biological processes, with 63 out of 74 GO terms affecting actin polymerization. Six major transcription factor families, including bZIP, C2H2, ERF, GATA, LBD, NAC, and HSF, were identified that were involved in the regulation of StFH genes in various abiotic stresses, including drought. Further, the 60 unique microRNAs targeted 24 StFH by regulating gene expression in response to drought stress were identified. The expression of StFH genes in 14 different tissues, particularly in drought-responsive tissues such as root, stem, shoot apex, and leaf, underscores their significance in managing drought stress. RNA-seq analysis of the drought-resistant Qingshu No. 9 variety revealed the potential role of up-regulated genes, including StFH2, StFH10, StFH19, and StFH25, in alleviating drought stress. Overall, these findings provide crucial insights into the response to drought stress in potatoes and can be utilized in breeding programs to develop potato cultivars with enhanced drought-tolerant traits.

Fluorescent probes for neuroscience: imaging ex vivo brain tissue sections

Neurobiological research relies heavily on imaging techniques, such as fluorescence microscopy, to understand neurological function and disease processes. However, the number and variety of fluorescent probes available for ex vivo tissue section imaging limits the advance of research in the field. In this review, we outline the current range of fluorescent probes that are available to researchers for ex vivo brain section imaging, including their physical and chemical characteristics, staining targets, and examples of discoveries for which they have been used. This review is organised into sections based on the biological target of the probe, including subcellular organelles, chemical species (e.g., labile metal ions), and pathological phenomenon (e.g., degenerating cells, aggregated proteins). We hope to inspire further development in this field, given the considerable benefits to be gained by the greater availability of suitably sensitive probes that have specificity for important brain tissue targets.

Therapeutic Potential of Silver Nitroprusside Nanoparticles for Melanoma

Melanoma has gained considerable attention due to its high mortality and morbidity rate worldwide. The currently available treatment options are associated with several limitations such as nonspecificity, drug resistance, easy clearance, low efficacy, toxicity-related issues, etc. To this end, nanotechnology has garnered significant attention for the treatment of melanoma. In the present manuscript, we have demonstrated the in vitro and in vivo anticancer activity of silver nitroprusside nanoparticles (abbreviated as AgNNPs) against melanoma. The AgNNPs exhibit cytotoxicity against B16F10 cells, which has been investigated by several in vitro experiments including [methyl 3H]-thymidine incorporation assay, cell cycle and apoptosis analysis by flow cytometry, and ROS generation through DCFDA, DHE, and DAF2A reagents. Further, the internalization of nanoparticles was determined by ICPOES analysis, while their colocalization was analyzed by confocal microscopy. Additionally, JC-1 staining is performed to examine mitochondrial membrane potential (MMP). Cytoskeleton integrity was observed by phalloidin staining. Expression of different markers (Ki-67, cytochrome c, and E-cadherin) was checked using an immunofluorescence assay. The in vivo therapeutic efficacy of AgNNPs has been validated in the melanoma model established by inoculating B16F10 cells into the dorsal right abdomen of C57BL/6J mice. The intraperitoneal administration of AgNNPs reduced melanoma growth and increased the survivability of tumor-bearing mice. The in vivo immunofluorescence studies (Ki-67, CD31, and E-cadherin) and TUNEL assay support the inhibitory and apoptotic nature of AgNNPs toward melanoma, respectively. Furthermore, the various signaling pathways and molecular mechanisms involved in anticancer activity are evaluated by Western blot analysis. These findings altogether demonstrate the promising anticancer potential of AgNNPs toward melanoma.

Sulfonamide-chalcone hybrid compound suppresses cellular adhesion and migration: Experimental and computational insight

In the present study, the effect of sulfonamide-chalcone 185 (SSC185) was investigated against B16-F10 metastatic melanoma cells aggressive actions, besides migration and adhesion processes, by in silico and in vitro assays. In silico studies were used to characterize the pharmacokinetic profile and possible targets of SSC185, using the pkCSM web server, and docking simulations with AutoDock Tools. Furthermore, the antimetastatic effect of SSC185 was investigated by in vitro experiments using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide), colony, scratch, and cell adhesion assays, and atomic force microscopy (AFM). The molecular docking results show better affinity of SSC185 with the metalloproteinases-2 (MMP-2) and α5β1 integrin. SSC185 effectively restricts the formation of colonies, migration, and adhesion of B16-F10 metastatic melanoma cells. Through the AFM images changes in cells morphology was identified, with a decrease in the filopodia and increase in the average cellular roughness. The results obtained demonstrate the potential of this molecule in inhibit the primordial steps for metastasis, which is responsible for a worse prognosis of late stage cancer, being the main cause of morbidity among cancer patients.

Sulforaphane suppresses bladder cancer metastasis via blocking actin nucleation-mediated pseudopodia formation

Metastasis is the primary stumbling block to the treatment of bladder cancer (BC). In order to spread, tumor cells must acquire increased migratory and invasive capacity, which is tightly linked with pseudopodia formation. Here, we unravel the effects of sulforaphane (SFN), an isothiocyanate in cruciferous vegetables, on the assembly of pseudopodia and BC metastasis, and its molecular mechanism in the process. Our database analysis revealed that in bladder tumor, the pseudopodia-associated genes CTTN, WASL and ACTR2/ARP2 are upregulated. SFN caused lamellipodia to collapse in BC cells by blocking the CTTN-ARP2 axis. SFN inhibited invadopodia formation and cell invasion by reducing WASL in different invasive BC cell lines. The production of ATP, essential for the assembly of pseudopodia, was significantly increased in bladder tumors and strongly inhibited by SFN. Overexpressing AKT1 reversed the downregulation of ATP in SFN-treated bladder cancer cells and restored filopodia and lamellipodia morphology and function. Bioluminescent imaging showed that SFN suppressed BC metastases to the lung of nude mice by downregulating Cttn and Arp2 expression. Our study reveals the mechanism of SFN action in inhibiting pseudopodia formation, and highlights potential targeting options for the therapy of metastatic bladder cancer.

Analyzing the Impact of the Highest Expressed Epstein-Barr Virus-Encoded microRNAs on the Host Cell Transcriptome

The Epstein-Barr virus (EBV) has a very high prevalence (>90% in adults), establishes a lifelong latency after primary infection, and exerts an oncogenic potential. This dsDNA virus encodes for various molecules, including microRNAs (miRs), which can be detected in the latent and lytic phases with different expression levels and affect, among others, immune evasion and malignant transformation. In this study, the different EBV miRs are quantified in EBV-positive lymphomas, and the impact on the host cell transcriptome of the most abundant EBV miRs will be analyzed using comparative RNA sequencing analyses. The EBV miRs ebv-miR-BART1, -BART4, -BART17, and -BHRF1-1 were most highly expressed, and their selective overexpression in EBV-negative human cells resulted in a large number of statistically significantly down- and up-regulated host cell genes. Functional analyses showed that these dysregulated target genes are involved in important cellular processes, including growth factor pathways such as WNT, EGF, FGF, and PDGF, as well as cellular processes such as apoptosis regulation and inflammation. Individual differences were observed between these four analyzed EBV miRs. In particular, ebv-miR-BHRF1-1 appears to be more important for malignant transformation and immune evasion than the other EBV miRs.

Mechanobiology in Metabolic Dysfunction-Associated Steatotic Liver Disease and Obesity

With the ongoing obesity epidemic, the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is expected to rise and necessitates a greater understanding of how the disease proceeds from benign excess lipid in hepatocytes to liver fibrosis and eventually to liver cancer. MASLD is caused, at least in part, by hepatocytes' storage of free fatty acids (FAs) that dysfunctional adipocytes are no longer able to store, and therefore, MASLD is a disease that involves both the liver and adipose tissues. The disease progression is not only facilitated by biochemical signals, but also by mechanical cues such as the increase in stiffness often seen with fibrotic fatty livers. The change in stiffness and accumulation of excess lipid droplets impact the ability of a cell to mechanosense and mechanotranduce, which perpetuates the disease. A mechanosensitive protein that is largely unexplored and could serve as a potential therapeutic target is the intermediate filament vimentin. In this review, we briefly summarize the recent research on hepatocyte and adipocyte mechanobiology and provide a synopsis of studies on the varied, and sometimes contradictory, roles of vimentin. This review is intended to benefit and encourage future studies on hepatocyte and adipocyte mechanobiology in the context of MASLD and obesity.

The Role of Vimentin in Human Corneal Fibroblast Spreading and Myofibroblast Transformation

Vimentin has been reported to play diverse roles in cell processes such as spreading, migration, cell-matrix adhesion, and fibrotic transformation. Here, we assess how vimentin impacts cell spreading, morphology, and myofibroblast transformation of human corneal fibroblasts. Overall, although knockout (KO) of vimentin did not dramatically impact corneal fibroblast spreading and mechanical activity (traction force), cell elongation in response to PDGF was reduced in vimentin KO cells as compared to controls. Blocking vimentin polymerization using Withaferin had even more pronounced effects on cell spreading and also inhibited cell-induced matrix contraction. Furthermore, although absence of vimentin did not completely block TGFβ-induced myofibroblast transformation, the degree of transformation and amount of αSMA protein expression was reduced. Proteomics showed that vimentin KO cells cultured in TGFβ had a similar pattern of protein expression as controls. One exception included periostin, an ECM protein associated with wound healing and fibrosis in other cell types, which was highly expressed only in Vim KO cells. We also demonstrate for the first time that LRRC15, a protein previously associated with myofibroblast transformation of cancer-associated fibroblasts, is also expressed by corneal myofibroblasts. Interestingly, proteins associated with LRRC15 in other cell types, such as collagen, fibronectin, β1 integrin and α11 integrin, were also upregulated. Overall, our data show that vimentin impacts both corneal fibroblast spreading and myofibroblast transformation. We also identified novel proteins that may regulate corneal myofibroblast transformation in the presence and/or absence of vimentin.

[Role and mechanism of cysteine and glycine-rich protein 2 in the malignant progression of neuroblastoma]

OBJECTIVE

To investigate the function and underlying mechanism of cysteine and glycine-rich protein 2 (CSRP2) in neuroblastoma (NB).

METHODS

The correlation between the expression level of CSRP2 mRNA and the prognosis of NB children in NB clinical samples was analyzed in R2 Genomics Analysis and Visualization Platform. The small interfering RNA (siRNA) targeting CSRP2 or CSRP2 plasmid were transfected to NB cell lines SK-N-BE(2) and SH-SY5Y. Cell proliferation was observed by crystal violet staining and real-time cellular analysis. The ability of colony formation of NB cells was observed by colony-forming unit assay. Immunofluorescence assay was used to detect the expression of the proliferation marker Ki-67. Flow cytometry analysis for cell cycle proportion was used with cells stained by propidium iodide (PI). Annexin V/7AAD was used to stain cells and analyze the percentage of cell apoptosis. The ability of cell migration was determined by cell wound-healing assay. The level of protein and mRNA expression of CSRP2 in NB primary tumor and NB cell lines were detected by Western blot and quantitative real-time PCR (RT-qPCR).

RESULTS

By analyzing the NB clinical sample databases, it was found that the expression levels of CSRP2 in high-risk NB with 3/4 stages in international neuroblastoma staging system (INSS) were significantly higher than that in low-risk NB with 1/2 INSS stages. The NB patients with high expression levels of CSRP2 were shown lower overall survival rate than those with low expression levels of CSRP2. We detected the protein levels of CSRP2 in the NB samples by Western blot, and found that the protein level of CSRP2 in 3/4 INSS stages was significantly higher than that in 1/2 INSS stages. Knockdown of CSRP2 inhibited cell viability and proliferation of NB cells. Overexpression of CSRP2 increased the proliferation of NB cells. Flow cytometry showed that the proportion of sub-G1, G0/G1 and S phase cells and Annexin V positive cells were increased after CSRP2 deficiency. In the cell wound-healing assay, the healing rate of NB cells was significantly attenuated after knockdown of CSRP2. Further mechanism studies showed that the proportion of the proliferation marker Ki-67 and the phosphorylation levels of extracellular signal-regulated kinases 1/2 (ERK1/2) were significantly decreased after CSRP2 knockdown.

CONCLUSION

CSRP2 is highly expressed in high-risk NB with 3/4 INSS stages, and the expression levels of CSRP2 are negatively correlated with the overall survival of NB patients. CSRP2 significantly increased the proliferation and cell migration of NB cells and inhibited cell apoptosis via the activation of ERK1/2. All these results indicate that CSRP2 promotes the progression of NB by activating ERK1/2, and this study will provide a potential target for high-risk NB therapy.

Human cerebral organoids: cellular composition and subcellular morphological features

Introduction

Human cerebral organoids (hCOs) derived from pluripotent stem cells are very promising for the study of neurodevelopment and the investigation of the healthy or diseased brain. To help establish hCOs as a powerful research model, it is essential to perform the morphological characterization of their cellular components in depth.

Methods

In this study, we analyzed the cell types consisting of hCOs after culturing for 45 days using immunofluorescence and reverse transcriptase qualitative polymerase chain reaction (RT-qPCR) assays. We also analyzed their subcellular morphological characteristics by transmission electron microscopy (TEM).

Results

Our results show the development of proliferative zones to be remarkably similar to those found in human brain development with cells having a polarized structure surrounding a central cavity with tight junctions and cilia. In addition, we describe the presence of immature and mature migrating neurons, astrocytes, oligodendrocyte precursor cells, and microglia-like cells.

Discussion

The ultrastructural characterization presented in this study provides valuable information on the structural development and morphology of the hCO, and this information is of general interest for future research on the mechanisms that alter the cell structure or function of hCOs.

Impact of ionizing radiation on cell-ECM mechanical crosstalk in breast cancer

The stiffness of the extracellular matrix plays a crucial role in cell motility and spreading, influencing cell morphology through cytoskeleton organization and transmembrane proteins' expression. In this context, mechanical characterization of both cells and the extracellular matrix gains prominence for enhanced diagnostics and clinical decision-making. Here, we investigate the combined effect of mechanotransduction and ionizing radiations on altering cells' mechanical properties, analysing mammary cell lines (MCF10A and MDA-MB-231) after X-ray radiotherapy (2 and 10 Gy). We found that ionizing radiations sensitively affect adenocarcinoma cells cultured on substrates mimicking cancerous tissue stiffness (15 kPa), inducing an increased structuration of paxillin-rich focal adhesions and cytoskeleton: this process translates in the augmentation of tension at the actin filaments level, causing cellular stiffness and consequently affecting cytoplasmatic/nuclear morphologies. Deeper exploration of the intricate interplay between mechanical factors and radiation should provide novel strategies to orient clinical outcomes.

Damage-repair events increase the instability of cortical microtubules in Arabidopsis

Microtubules rely on dynamic assembly and disassembly for their functions. Increasing evidences support that the damage-repair of microtubule lattices can affect microtubule dynamics in vitro and in animal cells. Here we successfully established a way for visualizing damage-repair sites on microtubule lattices in plant cells, via labeling the tubulin proteins with the photoconvertible fluorescent protein mEOS3.2. We observed that the crossovers of the microtubule lattice were more prone to be damaged and repaired, with the frequency of damage-repair events positively correlated with the crossing angle between microtubules. The microtubules with damage-repair events displayed shorter lifespans and significantly increased severing frequency compared with the undamaged microtubules. These observations suggested that the damage-repair events promoted instability of cortical microtubules in plant cells.

Identification of Curcumin Targets in the Brain of Epileptic Mice Using DARTS

Curcumin, a compound derived from turmeric, is traditionally utilized in East Asian medicine for treating various health conditions, including epilepsy. Despite its involvement in numerous cellular signaling pathways, the specific mechanisms and targets of curcumin in epilepsy treatment have remained unclear. Our study focused on identifying the primary targets and functional pathways of curcumin in the brains of epileptic mice. Using drug affinity responsive target stabilization (DARTS) and affinity chromatography, we identified key targets in the mouse brain, revealing 232 and 70 potential curcumin targets, respectively. Bioinformatics analysis revealed a strong association of these proteins with focal adhesions and cytoskeletal components. Further experiments using DARTS, along with immunofluorescence staining and cell migration assays, confirmed curcumin's ability to regulate the dynamics of focal adhesions and influence cell migration. This study not only advances our understanding of curcumin's role in epilepsy treatment but also serves as a model for identifying therapeutic targets in neurological disorders.

Sleep-wake body temperature regulates tau secretion in mice and correlates with CSF and plasma tau in humans

The sleep-wake cycle regulates interstitial fluid and cerebrospinal fluid (CSF) tau levels in both mouse and human by mechanisms that remain unestablished. Here, we reveal a novel pathway by which wakefulness increases extracellular tau levels in mouse and humans. In mice, higher body temperature (BT) associated with wakefulness and sleep deprivation increased CSF tau. In vitro, wakefulness temperatures upregulated tau secretion via a temperature-dependent increase in activity and expression of unconventional protein secretion pathway-1 components, namely caspase-3-mediated C-terminal cleavage of tau (TauC3), and membrane expression of PIP2 and syndecan-3. In humans, the increase in both CSF and plasma tau levels observed post-wakefulness correlated with BT increase during wakefulness. Our findings suggest sleep-wake variation in BT may contribute to regulating extracellular tau levels, highlighting the importance of thermoregulation in pathways linking sleep disturbance to neurodegeneration, and the potential for thermal intervention to prevent or delay tau-mediated neurodegeneration.

DNAJA1‑knockout alleviates heat stroke‑induced endothelial barrier disruption via improving thermal tolerance and suppressing the MLCK‑MLC signaling pathway

Endothelial barrier disruption plays a key role in the pathophysiology of heat stroke (HS). Knockout of DNAJA1 (DNAJA1‑KO) is thought to be protective against HS based on a genome‑wide CRISPR‑Cas9 screen experiment. The present study aimed to illustrate the function of DNAJA1‑KO against HS in human umbilical vein endothelial cells. DNAJA1‑KO cells were infected using a lentivirus to investigate the role of DNAJA1‑KO in HS‑induced endothelial barrier disruption. It was shown that DNAJA1‑KO could ameliorate decreased cell viability and increased cell injury, according to the results of Cell Counting Kit‑8 and lactate dehydrogenase assays. Moreover, HS‑induced endothelial cell apoptosis was inhibited by DNAJA1‑KO, as indicated by Annexin V‑FITC/PI staining and cleaved‑caspase‑3 expression using flow cytometry and western blotting, respectively. Furthermore, the endothelial barrier function, as measured by transepithelial electrical resistance and FITC‑Dextran, was sustained during HS. DNAJA1‑KO was not found to have a significant effect on the expression and distribution of cell junction proteins under normal conditions without HS. However, DNAJA1‑KO could effectively protect the HS‑induced decrease in the expression and distribution of cell junction proteins, including zonula occludens‑1, claudin‑5, junctional adhesion molecule A and occludin. A total of 4,394 proteins were identified using proteomic analysis, of which 102 differentially expressed proteins (DEPs) were activated in HS‑induced wild‑type cells and inhibited by DNAJA1‑KO. DEPs were investigated by enrichment analysis, which demonstrated significant enrichment in the 'calcium signaling pathway' and associations with vascular‑barrier regulation. Furthermore, the 'myosin light‑chain kinase (MLCK)‑MLC signaling pathway' was proven to be activated by HS and inhibited by DNAJA1‑KO, as expected. Moreover, DNAJA1‑KO mice and a HS mouse model were established to demonstrate the protective effects on endothelial barrier in vivo. In conclusion, the results of the present study suggested that DNAJA1‑KO alleviates HS‑induced endothelial barrier disruption by improving thermal tolerance and suppressing the MLCK‑MLC signaling pathway.

Regulation of Microtubule Stability in Pulmonary Microvascular Endothelial Cells in Rats with Severe Acute Pancreatitis: Qingyi Decoction is a Potential CDK5 Inhibitor

Purpose

Explore the therapeutic effects and regulatory mechanism of Qingyi Decoction (QYD) on severe acute pancreatitis (SAP) associated acute lung injury (ALI).

Methods

We identified the constituents absorbed into the blood of QYD based on a network pharmacological strategy. The differentially expressed genes from the GEO database were screened to identify the critical targets of QYD treatment of SAP-ALI. The SAP-ALI rat model was constructed.Some methods were used to evaluate the efficacy and mechanism of QYD in treating SAP-ALI. LPS-stimulated pulmonary microvascular endothelial cell injury simulated the SAP-induced pulmonary endothelial injury model. We further observed the therapeutic effect of QYD and CDK5 plasmid transfection on endothelial cell injury.

Results

18 constituents were absorbed into the blood, and 764 targets were identified from QYD, 25 of which were considered core targets for treating SAP-ALI. CDK5 was identified as the most critical gene. The results of differential expression analysis showed that the mRNA expression level of CDK5 in the blood of SAP patients was significantly up-regulated compared with that of healthy people. Animal experiments have demonstrated that QYD can alleviate pancreatic and lung injury inflammatory response and reduce the upregulation of CDK5 in lung tissue. QYD or CDK5 inhibitors could decrease the expression of NFAT5 and GEF-H1, and increase the expression of ACE-tub in SAP rat lung tissue. Cell experiments proved that QYD could inhibit the expression of TNF-α and IL-6 induced by LPS. Immunofluorescence results suggested that QYD could alleviate the cytoskeleton damage of endothelial cells, and the mechanism might be related to the inhibition of CDK5-mediated activation of NFAT5, GEF-H1, and ACE-tub.

Conclusion

CDK5 has been identified as a critical target for pulmonary endothelial injury of SAP-ALI. QYD may partially alleviate microtubule disassembly by targeting the CDK5/NFAT5/GEF-H1 signaling pathway, thus relieving SAP-induced pulmonary microvascular endothelial cell injury.

Labile assembly of a tardigrade protein induces biostasis

Tardigrades are microscopic animals that survive desiccation by inducing biostasis. To survive drying tardigrades rely on intrinsically disordered CAHS proteins, which also function to prevent perturbations induced by drying in vitro and in heterologous systems. CAHS proteins have been shown to form gels both in vitro and in vivo, which has been speculated to be linked to their protective capacity. However, the sequence features and mechanisms underlying gel formation and the necessity of gelation for protection have not been demonstrated. Here we report a mechanism of fibrillization and gelation for CAHS D similar to that of intermediate filament assembly. We show that in vitro, gelation restricts molecular motion, immobilizing and protecting labile material from the harmful effects of drying. In vivo, we observe that CAHS D forms fibrillar networks during osmotic stress. Fibrillar networking of CAHS D improves survival of osmotically shocked cells. We observe two emergent properties associated with fibrillization; (i) prevention of cell volume change and (ii) reduction of metabolic activity during osmotic shock. We find that there is no significant correlation between maintenance of cell volume and survival, while there is a significant correlation between reduced metabolism and survival. Importantly, CAHS D's fibrillar network formation is reversible and metabolic rates return to control levels after CAHS fibers are resolved. This work provides insights into how tardigrades induce reversible biostasis through the self-assembly of labile CAHS gels.

Changes Induced by P2X7 Receptor Stimulation of Human Glioblastoma Stem Cells in the Proteome of Extracellular Vesicles Isolated from Their Secretome

Extracellular vesicles (EVs) are secreted from many tumors, including glioblastoma multiforme (GBM), the most common and lethal brain tumor in adults, which shows high resistance to current therapies and poor patient prognosis. Given the high relevance of the information provided by cancer cell secretome, we performed a proteomic analysis of microvesicles (MVs) and exosomes (EXOs) released from GBM-derived stem cells (GSCs). The latter, obtained from the brain of GBM patients, expressed P2X7 receptors (P2X7Rs), which positively correlate with GBM growth and invasiveness. P2X7R stimulation of GSCs caused significant changes in the EV content, mostly ex novo inducing or upregulating the expression of proteins related to cytoskeleton reorganization, cell motility/spreading, energy supply, protection against oxidative stress, chromatin remodeling, and transcriptional regulation. Most of the induced/upregulated proteins have already been identified as GBM diagnostic/prognostic factors, while others have only been reported in peripheral tumors. Our findings indicate that P2X7R stimulation enhances the transport and, therefore, possible intercellular exchange of GBM aggressiveness-increasing proteins by GSC-derived EVs. Thus, P2X7Rs could be considered a new druggable target of human GBM, although these data need to be confirmed in larger experimental sets.

Role of Cytoskeletal Elements in Regulation of Synaptic Functions: Implications Toward Alzheimer's Disease and Phytochemicals-Based Interventions

Alzheimer's disease (AD), a multifactorial disease, is characterized by the accumulation of neurofibrillary tangles (NFTs) and amyloid beta (Aβ) plaques. AD is triggered via several factors like alteration in cytoskeletal proteins, a mutation in presenilin 1 (PSEN1), presenilin 2 (PSEN2), amyloid precursor protein (APP), and post-translational modifications (PTMs) in the cytoskeletal elements. Owing to the major structural and functional role of cytoskeletal elements, like the organization of axon initial segmentation, dendritic spines, synaptic regulation, and delivery of cargo at the synapse; modulation of these elements plays an important role in AD pathogenesis; like Tau is a microtubule-associated protein that stabilizes the microtubules, and it also causes inhibition of nucleo-cytoplasmic transportation by disrupting the integrity of nuclear pore complex. One of the major cytoskeletal elements, actin and its dynamics, regulate the dendritic spine structure and functions; impairments have been documented towards learning and memory defects. The second major constituent of these cytoskeletal elements, microtubules, are necessary for the delivery of the cargo, like ion channels and receptors at the synaptic membranes, whereas actin-binding protein, i.e., Cofilin's activation form rod-like structures, is involved in the formation of paired helical filaments (PHFs) observed in AD. Also, the glial cells rely on their cytoskeleton to maintain synaptic functionality. Thus, making cytoskeletal elements and their regulation in synaptic structure and function as an important aspect to be focused for better management and targeting AD pathology. This review advocates exploring phytochemicals and Ayurvedic plant extracts against AD by elucidating their neuroprotective mechanisms involving cytoskeletal modulation and enhancing synaptic plasticity. However, challenges include their limited bioavailability due to the poor solubility and the limited potential to cross the blood-brain barrier (BBB), emphasizing the need for targeted strategies to improve therapeutic efficacy.

Label-free visualization and quantification of the drug-type-dependent response of tumor spheroids by dynamic optical coherence tomography

We demonstrate label-free dynamic optical coherence tomography (D-OCT)-based visualization and quantitative assessment of patterns of tumor spheroid response to three anti-cancer drugs. The study involved treating human breast adenocarcinoma (MCF-7 cell-line) with paclitaxel (PTX), tamoxifen citrate (TAM), and doxorubicin (DOX) at concentrations of 0 (control), 0.1, 1, and 10 µM for 1, 3, and 6 days. In addition, fluorescence microscopy imaging was performed for reference. The D-OCT imaging was performed using a custom-built OCT device. Two algorithms, namely logarithmic intensity variance (LIV) and late OCT correlation decay speed (OCDS[Formula: see text]) were used to visualize the tissue dynamics. The spheroids treated with 0.1 and 1 µM TAM appeared similar to the control spheroid, whereas those treated with 10 µM TAM had significant structural corruption and decreasing LIV and OCDS[Formula: see text] over treatment time. The spheroids treated with PTX had decreasing volumes and decrease of LIV and OCDS[Formula: see text] signals over time at most PTX concentrations. The spheroids treated with DOX had decreasing and increasing volumes over time at DOX concentrations of 1 and 10 µM, respectively. Meanwhile, the LIV and OCDS[Formula: see text] signals decreased over treatment time at all DOX concentrations. The D-OCT, particularly OCDS[Formula: see text], patterns were consistent with the fluorescence microscopic patterns. The diversity in the structural and D-OCT results among the drug types and among the concentrations are explained by the mechanisms of the drugs. The presented results suggest that D-OCT is useful for evaluating the difference in the tumor spheroid response to different drugs and it can be a useful tool for anti-cancer drug testing.

Microtubules provide force to promote membrane uncoating in vacuolar escape for a cyto-invasive bacterial pathogen

Intracellular bacterial pathogens gain entry to mammalian cells inside a vacuole derived from the host membrane. Some of them escape the bacteria-containing vacuole (BCV) and colonize the cytosol. Bacteria replicating within BCVs coopt the microtubule network to position it within infected cells, whereas the role of microtubules for cyto-invasive pathogens remains obscure. Here, we show that the microtubule motor cytoplasmic dynein-1 and specific activating adaptors are hijacked by the enterobacterium Shigella flexneri. These host proteins were found on infection-associated macropinosomes (IAMs) formed during Shigella internalization. We identified Rab8 and Rab13 as mediators of dynein recruitment and discovered that the Shigella effector protein IpaH7.8 promotes Rab13 retention on moving BCV membrane remnants, thereby facilitating membrane uncoating of the Shigella-containing vacuole. Moreover, the efficient unpeeling of BCV remnants contributes to a successful intercellular spread. Taken together, our work demonstrates how a bacterial pathogen subverts the intracellular transport machinery to secure a cytosolic niche.

Dehydration-responsive cytoskeleton proteome of rice reveals reprograming of key molecular pathways to mediate metabolic adaptation and cell survival

The plant cytoskeletal proteins play a key role that control cytoskeleton dynamics, contributing to crucial biological processes such as cell wall morphogenesis, stomatal conductance and abscisic acid accumulation in repercussion to water-deficit stress or dehydration. Yet, it is still completely unknown which specific biochemical processes and regulatory mechanisms the cytoskeleton uses to drive dehydration tolerance. To better understand the role of cytoskeleton, we developed the dehydration-responsive cytoskeletal proteome map of a resilient rice cultivar. Initially, four-week-old rice plants were exposed to progressive dehydration, and the magnitude of dehydration-induced compensatory physiological responses was monitored in terms of physicochemical indices. The organelle fractionation in conjunction with label-free quantitative proteome analysis led to the identification of 955 dehydration-responsive cytoskeletal proteins (DRCPs). To our knowledge, this is the first report of a stress-responsive plant cytoskeletal proteome, representing the largest inventory of cytoskeleton and cytoskeleton-associated proteins. The DRCPs were apparently involved in a wide array of intra-cellular molecules transportation, organelles positioning, cytoskeleton organization followed by different metabolic processes including amino acid metabolism. These findings presented open a unique view on global regulation of plant cytoskeletal proteome is intimately linked to cellular metabolic rewiring of adaptive responses, and potentially confer dehydration tolerance, especially in rice, and other crop species, in general.

Cortactin is in a complex with VE-cadherin and is required for endothelial adherens junction stability through Rap1/Rac1 activation

Vascular permeability is mediated by Cortactin (Cttn) and regulated by several molecules including cyclic-adenosine-monophosphate, small Rho family GTPases and the actin cytoskeleton. However, it is unclear whether Cttn directly interacts with any of the junctional components or if Cttn intervenes with signaling pathways affecting the intercellular contacts and the cytoskeleton. To address these questions, we employed immortalized microvascular myocardial endothelial cells derived from wild-type and Cttn-knock-out mice. We found that lack of Cttn compromised barrier integrity due to fragmented membrane distribution of different junctional proteins. Moreover, immunoprecipitations revealed that Cttn is within the VE-cadherin-based adherens junction complex. In addition, lack of Cttn slowed-down barrier recovery after Ca2+ repletion. The role of Cttn for cAMP-mediated endothelial barrier regulation was analyzed using Forskolin/Rolipram. In contrast to Cttn-KO, WT cells reacted with increased transendothelial electrical resistance. Absence of Cttn disturbed Rap1 and Rac1 activation in Cttn-depleted cells. Surprisingly, despite the absence of Cttn, direct activation of Rac1/Cdc42/RhoA by CN04 increased barrier resistance and induced well-defined cortical actin and intracellular actin bundles. In summary, our data show that Cttn is required for basal barrier integrity by allowing proper membrane distribution of junctional proteins and for cAMP-mediated activation of the Rap1/Rac1 signaling pathway.

Relevance Analysis of TPM2 and Clinicopathological Characteristics in Breast Cancer

Background

The function of tropomyosin 2 (TPM2) in breast cancer is still far understudied. In this study, we aim to explore the roles of TPM2 in breast cancer progression.

Methods

This research included 155 breast cancer tissues. The expression of TPM2 was analyzed by immunohistochemical staining and grading. The mRNA expression of TPM2 in pan-cancer was analyzed with The Cancer Genome Atlas (TCGA) data plate form. The differential expression of TPM2 protein and the differential promoter methylation level of TPM2 between breast cancer tissues and normal breast tissues were analyzed by the UALCAN online database. The relationship between TPM2 and signaling pathways was interpreted by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) pathway enrichment analyses. The survival curve of TPM2 was analyzed across the Kaplan-Meier plotter online database. Furthermore, the relationship between TPM2 expression and infiltrating macrophages was validated through in vitro co-culture experiments.

Results

TPM2 expression was significantly down-regulated in breast cancer samples. In addition, TPM2 expression was correlated with lymph node metastasis and high-grade histopathological morphology. The receiver operating characteristic (ROC) curve indicated that TPM2 expression could well distinguish between normal breast tissue and breast cancer tissue. TPM2 may have potential value in breast cancer diagnosis. Bioinformatics analysis illustrated that TPM2 was mainly involved in extracellular matrix organization, collagen fibril organization, cell junction assembly, focal adhesion, cAMP signaling pathway, estrogen signaling pathway, Wnt signaling pathway, and adaptive immune system. TPM2 expression was correlated with immune infiltrating cells and immune checkpoint molecules. Our in vitro co-culture experiments showed that the M2 macrophages could upregulate the expression of TPM2.

Conclusion

TPM2 may play key roles in breast cancer occurrence and development, especially in cancer metastasis. TPM2 may be a potential biomarker for breast cancer diagnosis.

Calcium hypochlorite cytotoxicity mechanism in fibroblasts and effect on osteoblast mineralization

AIM

To determine the cytotoxicity mechanism of 2.5% calcium hypochlorite [Ca(OCl)2 ] in L929 fibroblasts and the effect of this solution on human osteoblast-like cells (Saos-2) mineralization, compared to that of 2.5% sodium hypochlorite (NaOCl).

METHODOLOGY

L929 fibroblasts were exposed to Ca(OCl)2 and NaOCl at different dilutions for 10 min. Cell metabolism was assessed by methyl-thiazole-tetrazolium (MTT); lysosome integrity, by neutral red (NR) assay; type of cell death, by flow cytometry (apoptosis/necrosis); cytoskeleton, by actin and α-tubulin fluorescence and cell ultrastructure, by transmission electron microscopy (TEM). The alkaline phosphatase (ALP) activity and mineralized nodule formation were determined in Saos-2 by thymolphthalein release and alizarin red staining (ARS), respectively. The data were analysed by two-way anova and Bonferroni's post-test (α = .05).

RESULTS

Ca(OCl)2 promoted higher cell viability and a lower percentage of apoptosis and necrosis than NaOCl (p < .05). Ca(OCl)2 and NaOCl decreased cell metabolism and lysosome integrity, induced the breakdown of microtubules and actin filaments, promoted alterations of rough endoplasmic reticulum and disruption of mitochondrial cristae. Additionally, Ca(OCl)2 did not induce ALP activity and had no effect on mineralized nodules formation.

CONCLUSIONS

Although Ca(OCl)2 and NaOCl promoted the same cytotoxicity mechanism, Ca(OCl)2 was less cytotoxic than NaOCl. As for ALP activity, no differences were observed between NaOCl and Ca(OCl)2 . The production of mineralized nodules induced by Ca(OCl)2 was lower than those induced by NaOCl, but was not different from those induced by the control group.

Differences and similarities in biophysical and biological characteristics between U87 MG glioblastoma and astrocyte cells

Current cancer studies focus on molecular-targeting diagnostics and interactions with surroundings; however, there are still gaps in characterization based on topological differences and elemental composition. Glioblastoma (GBM cells; GBMCs) is an astrocytic aggressive brain tumor. At the molecular level, GBMCs and astrocytes may differ, and cell elemental/topological analysis is critical for identifying potential new cancer targets. Here, we used U87 MG cells for GBMCS. U87 MG cell lines, which are frequently used in glioblastoma research, are an important tool for studying the various features and underlying mechanisms of this aggressive brain tumor. For the first time, atomic force microscopy (AFM), scanning electron microscopy (SEM) accompanied by energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) are used to report the topology and chemistry of cancer (U87 MG) and healthy (SVG p12) cells. In addition, F-actin staining and cytoskeleton-based gene expression analyses were performed. The degree of gene expression for genes related to the cytoskeleton was similar; however, the intensity of F-actin, anisotropy values, and invasion-related genes were different. Morphologically, GBMCs were longer and narrower while astrocytes were shorter and more disseminated based on AFM. Furthermore, the roughness values of these cells differed slightly between the two call types. In contrast to the rougher astrocyte surfaces in the lamellipodial area, SEM-EDS analysis showed that elongated GBMCs displayed filopodial protrusions. Our investigation provides considerable further insight into rapid cancer cell characterization in terms of a combinatorial spectroscopic and microscopic approach.

The Remodulation of Actin Bundles during the Stimulation of Mitochondria in Adult Human Fibroblasts in Response to Light

β-actin belongs to cytoskeletal structures that change dynamically in cells according to various stimuli. Human skin can be considered as an organ that is very frequently exposed to various stress factors, of which light plays an important role. The present study focuses on adult human fibroblasts exposed to two types of light stress. Orange light with a wavelength of 590 nm was used here to stimulate the photosensitizer localized in the cells as a residual dose of photodynamic therapy (PDT). On the other hand, near-infrared light with a wavelength of 808 nm was considered for photobiomodulation (PBM), which is often used in healing processes. Confocal fluorescence microscopy was used to observe changes in intercellular communication, mitochondrial structures, and cytoskeletal dynamics defined by the remodulation of β-actin of fibroblasts. The number of β-actin bundles forming spherical structures was detected after light exposure. These structures as β-actin oligomers were confirmed with super-resolution microscopy. While PDT led to the disintegration of actin oligomers, PBM increased their number. The interaction of β-actin with mitochondria was observed. The combination of PDT and PBM treatments is important to minimize the side effects of cancer treatment with PDT on healthy cells, as shown by the cell metabolism assay in this work. In this work, β-actin is presented as an important parameter that changes and is involved in the response of cells to PDT and PBM.

The discovery of water-soluble indazole derivatives as potent microtubule polymerization inhibitors

Taking a previously discovered indazole derivative 1 as a lead, systematic structural modifications were performed with an indazole core at the 1- and 6-positions to improve its aqueous solubility. Among the designed indazole derivatives, 6-methylpyridin-3-yl indazole derivative 8l and 1H-indol-4-yl indazole derivative 8m exhibited high potency in the low nanomolar range against A549, Huh-7, and T24 cancer cells, including Taxol-resistant variant cells (A549/Tax). As a hydrochloride salt, 8l exhibited much improved aqueous solubility, and its log P value fell into a favorable range. In mechanistic studies, 8l impeded tubulin polymerization through interacting with the colchicine site, resulting in cell cycle arrest and cellular apoptosis. In addition, compared to lead compound 1, 8l reduced cell migration and led to more potent inhibition of tumor growth in vivo without apparent toxicity. In summary, indazole derivative 8l could work as a potential anticancer agent and deserves further investigation for cancer therapy.

Cancer Development in Hepatocytes by Long-Term Induction of Hypoxic Hepatocellular Carcinoma Cell (HCC)-Derived Exosomes In Vivo and In Vitro

Hypoxic tumor cell-derived exosomes play a key role in the occurrence, development, and metastasis of tumors. However, the mechanism of hypoxia-mediated metastasis remains unclear. In this study, hypoxic hepatocellular carcinoma cell (HCC-LM3)-derived exosomes (H-LM3-exos) were used to induce hepatocytes (HL-7702) over a long term (40 passages in 120 days). A nude mouse experiment further verified the effect of H-LM3-exos on tumor growth and metastasis. The process of cancer development in hepatocytes induced by H-LM3-exos was analyzed using both biological and physical techniques, and the results showed that the proliferation and soft agar growth abilities of the transformed cells were enhanced. The concentration of tumor markers secreted by transformed cells was increased, the cytoskeleton was disordered, and the migration ability was enhanced and was accompanied by epithelial-mesenchymal transition (EMT). Transcriptome results showed that differentially expressed genes between transformed cells and hepatocytes were enriched in cancer-related signaling pathways. The degree of cancer development in transformed cells was enhanced by an increase in H-LM3-exos-induced passages. Nude mice treated with different concentrations of H-LM3-exos showed different degrees of tumor growth and liver lesions. The physical properties of the cells were characterized by atomic force microscopy. Compared with the hepatocytes, the height and roughness of the transformed cells were increased, while the adhesion and elastic modulus were decreased. The changes in physical properties of primary tumor cells and hepatocytes in nude mice were consistent with this trend. Our study linking omics with the physical properties of cells provides a new direction for studying the mechanisms of cancer development and metastasis.

Disturbing cytoskeleton by engineered nanomaterials for enhanced cancer therapeutics

Cytoskeleton plays a significant role in the shape change, migration, movement, adhesion, cytokinesis, and phagocytosis of tumor cells. In clinical practice, some anti-cancer drugs achieve cytoskeletal therapeutic effects by acting on different cytoskeletal protein components. However, in the absence of cell-specific targeting, unnecessary cytoskeletal recombination in organisms would be disastrous, which would also bring about severe side effects during anticancer process. Nanomedicine have been proven to be superior to some small molecule drugs in cancer treatment due to better stability and targeting, and lower side effects. Therefore, this review summarized the recent developments of various nanomaterials disturbing cytoskeleton for enhanced cancer therapeutics, including carbon, noble metals, metal oxides, black phosphorus, calcium, silicon, polymers, peptides, and metal-organic frameworks, etc. A comprehensive analysis of the characteristics of cytoskeleton therapy as well as the future prospects and challenges towards clinical application were also discussed. We aim to drive on this emerging topic through refreshing perspectives based on our own work and what we have also learnt from others. This review will help researchers quickly understand relevant cytoskeletal therapeutic information to further advance the development of cancer nanomedicine.

TPPP3 promote epithelial-mesenchymal transition via Snail1 in glioblastoma

Tubulin polymerization promoting protein 3 (TPPP3), a member of the tubulin polymerization family, participates in cell progressions in several human cancers, its biological function and the underlying mechanisms in glioblastoma multiforme (GBM) remain unclear. Here, we investigated the role and application value of TPPP3 in gliomas and found that the expression of TPPP3 in glioma was higher than that in normal brain tissue (NBT), and increased with the grade of glioma. Up-regulation of TPPP3 expression in glioblastoma cells confer stronger ability of migration, invasion, proliferation and lower apoptosis in vitro. Inhibition of TPPP3 expression in GBM could reduce the migration, invasion, proliferation and induce the apoptosis of glioblastoma cells. TPPP3 affected the process of EMT by regulating the expression of Snail 1 protein. In clinical data analysis, we found a positive correlation between TPPP3 and Snail1 protein expression levels in glioblastomas. Low TPPP3 expression leads to better survival expectations in glioblastomas patients. The content of this study paves the way for further in-depth exploration of the role of TPPP3 in glioblastoma in the future, and provides new treatment and research directions.

O-GlcNAcylation regulates neurofilament-light assembly and function and is perturbed by Charcot-Marie-Tooth disease mutations

The neurofilament (NF) cytoskeleton is critical for neuronal morphology and function. In particular, the neurofilament-light (NF-L) subunit is required for NF assembly in vivo and is mutated in subtypes of Charcot-Marie-Tooth (CMT) disease. NFs are highly dynamic, and the regulation of NF assembly state is incompletely understood. Here, we demonstrate that human NF-L is modified in a nutrient-sensitive manner by O-linked-β-N-acetylglucosamine (O-GlcNAc), a ubiquitous form of intracellular glycosylation. We identify five NF-L O-GlcNAc sites and show that they regulate NF assembly state. NF-L engages in O-GlcNAc-mediated protein-protein interactions with itself and with the NF component α-internexin, implying that O-GlcNAc may be a general regulator of NF architecture. We further show that NF-L O-GlcNAcylation is required for normal organelle trafficking in primary neurons. Finally, several CMT-causative NF-L mutants exhibit perturbed O-GlcNAc levels and resist the effects of O-GlcNAcylation on NF assembly state, suggesting a potential link between dysregulated O-GlcNAcylation and pathological NF aggregation. Our results demonstrate that site-specific glycosylation regulates NF-L assembly and function, and aberrant NF O-GlcNAcylation may contribute to CMT and other neurodegenerative disorders.

A Proteomics-Based Identification of the Biological Networks Mediating the Impact of Epigallocatechin-3-Gallate on Trophoblast Cell Migration and Invasion, with Potential Implications for Maternal and Fetal Health

Trophoblast migration and invasion play crucial roles in placental development. However, the effects of (-)-epigallocatechin-3-gallate (EGCG) on trophoblast cell functions remain largely unexplored. In this study, we investigated the impact of EGCG on the survival of trophoblast cells and employed a proteomics analysis to evaluate its influence on trophoblast cell migration and invasion. Be-Wo trophoblast cells were treated with EGCG, and a zone closure assay was conducted to assess the cell migration and invasion. Subsequently, a proteomics analysis was performed on the treated and control groups, followed by a bioinformatics analysis to evaluate the affected biological pathways and protein networks. A quantitative real-time PCR and Western blot analysis were carried out to validate the proteomics findings. Our results showed that EGCG significantly suppressed the trophoblast migration and invasion at a concentration not affecting cell survival. The proteomics analysis revealed notable differences in the protein expression between the EGCG-treated and control groups. Specifically, EGCG downregulated the signaling pathways related to EIF2, mTOR, and estrogen response, as well as the processes associated with the cytoskeleton, extracellular matrix, and protein translation. Conversely, EGCG upregulated the pathways linked to lipid degradation and oxidative metabolism. The quantitative PCR showed that EGCG modulated protein expression by regulating gene transcription, and the Western blot analysis confirmed its impact on cytoskeleton and extracellular matrix reorganization. These findings suggest EGCG may inhibit trophoblast migration and invasion through multiple signaling pathways, highlighting the potential risks associated with consuming EGCG-containing products during pregnancy. Future research should investigate the impact of EGCG intake on maternal and fetal proteoforms.

Human ACE2 protein is a molecular switch controlling the mode of SARS-CoV-2 transmission

BACKGROUND

Human angiotensin-converting enzyme 2 (hACE2) is the receptor mediating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. hACE2 expression is low in the lungs and is upregulated after SARS-CoV-2 infection. How such a hACE2-limited pulmonary environment supports efficient virus transmission and how dynamic hACE2 expression affects SARS-CoV-2 infection are unclear.

METHODS

We generated stable cell lines with different expression levels of hACE2 to evaluate how the hACE2 expression level can affect SARS-CoV-2 transmission.

RESULTS

We demonstrated that the hACE2 expression level controls the mode of SARS-CoV-2 transmission. The hACE2-limited cells have an advantage for SARS-CoV-2 shedding, which leads to cell-free transmission. By contrast, enhanced hACE2 expression facilitates the SARS-CoV-2 cell-to-cell transmission. Furthermore, this cell-to-cell transmission is likely facilitated by hACE2-containing vesicles, which accommodate numerous SARS-CoV-2 virions and transport them to neighboring cells through intercellular extensions.

CONCLUSIONS

This hACE2-mediated switch between cell-free and cell-to-cell transmission routes provides SARS-CoV-2 with advantages for either viral spread or evasion of humoral immunity, thereby contributing to the COVID-19 pandemic and pathogenesis.

Uncovering the role of cytoskeleton proteins in the formation of neutrophil extracellular traps

Neutrophils are a type of lymphocyte involved in innate immune defense. In response to specific stimuli, these phagocytic cells undergo a unique form of cell death, NETosis, during which they release neutrophil extracellular traps (NETs) composed of modified chromatin structures decorated with cytoplasmic and granular proteins. Multiple proteins and pathways have been implicated in the formation of NETs. The cytoskeleton, an interconnected network of filamentous polymers and regulatory proteins, plays a crucial role in resisting deformation, transporting intracellular cargo, and changing shape during movement of eukaryotic cells. It may also have evolved to defend eukaryotic organisms against infection. Recent research focuses on understanding the mechanisms underlying NETs formation and how cytoskeletal networks contribute to this process, by identifying enzymes that trigger NETosis or interact with NETs and influence cellular behavior through cytoskeletal dynamics. An enhanced understanding of the complex relationship between the cytoskeleton and NET formation will provide a framework for future research and the development of targeted therapeutic strategies, and supports the notion that the long-lived cytoskeleton structures may have a lasting impact on this area of research.

Light-Based 3D Printing of Gelatin-Based Biomaterial Inks to Create a Physiologically Relevant In Vitro Fish Intestinal Model

To provide prominent accessibility of fishmeal to the European population, the currently available, time- and cost-extensive feeding trials, which evaluate fish feed, should be replaced. The current paper reports on the development of a novel 3D culture platform, mimicking the microenvironment of the intestinal mucosa in vitro. The key requirements of the model include sufficient permeability for nutrients and medium-size marker molecules (equilibrium within 24 h), suitable mechanical properties (G' < 10 kPa), and close morphological similarity to the intestinal architecture. To enable processability with light-based 3D printing, a gelatin-methacryloyl-aminoethyl-methacrylate-based biomaterial ink is developed and combined with Tween 20 as porogen to ensure sufficient permeability. To assess the permeability properties of the hydrogels, a static diffusion setup is utilized, indicating that the hydrogel constructs are permeable for a medium size marker molecule (FITC-dextran 4 kg mol-1 ). Moreover, the mechanical evaluation through rheology evidence a physiologically relevant scaffold stiffness (G' = 4.83 ± 0.78 kPa). Digital light processing-based 3D printing of porogen-containing hydrogels results in the creation of constructs exhibiting a physiologically relevant microarchitecture as evidenced through cryo-scanning electron microscopy. Finally, the combination of the scaffolds with a novel rainbow trout (Oncorhynchus mykiss) intestinal epithelial cell line (RTdi-MI) evidence scaffold biocompatibility.

Mechanical Properties and Nanomotion of BT-20 and ZR-75 Breast Cancer Cells Studied by Atomic Force Microscopy and Optical Nanomotion Detection Method

Cells of two molecular genetic types of breast cancer-hormone-dependent breast cancer (ZR-75 cell line) and triple-negative breast cancer (BT-20 cell line)-were studied using atomic force microscopy and an optical nanomotion detection method. Using the Peak Force QNM and Force Volume AFM modes, we revealed the unique patterns of the dependence of Young's modulus on the indentation depth for two cancer cell lines that correlate with the features of the spatial organization of the actin cytoskeleton. Within a 200-300 nm layer just under the cell membrane, BT-20 cells are stiffer than ZR-75 cells, whereas in deeper cell regions, Young's modulus of ZR-75 cells exceeds that of BT-20 cells. Two cancer cell lines also displayed a difference in cell nanomotion dynamics upon exposure to cytochalasin D, a potent actin polymerization inhibitor. The drug strongly modified the nanomotion pattern of BT-20 cells, whereas it had almost no effect on the ZR-75 cells. We are confident that nanomotion monitoring and measurement of the stiffness of cancer cells at various indentation depths deserve further studies to obtain effective predictive parameters for use in clinical practice.

Fidgetin-like 2 depletion enhances cell migration by regulating GEF-H1, RhoA, and FAK

The microtubule (MT) cytoskeleton and its dynamics play an important role in cell migration. Depletion of the microtubule-severing enzyme Fidgetin-like 2 (FL2), a regulator of MT dynamics at the leading edge of migrating cells, leads to faster and more efficient cell migration. Here we examine how siRNA knockdown of FL2 increases cell motility. Förster resonance energy transfer biosensor studies shows that FL2 knockdown decreases activation of the p21 Rho GTPase, RhoA, and its activator GEF-H1. Immunofluorescence studies reveal that GEF-H1 is sequestered by the increased MT density resulting from FL2 depletion. Activation of the Rho GTPase, Rac1, however, does not change after FL2 knockdown. Furthermore, FL2 depletion leads to an increase in focal adhesion kinase activation at the leading edge, as shown by immunofluorescence studies, but no change in actin dynamics, as shown by fluorescence recovery after photobleaching. We believe these results expand our understanding of the role of MT dynamics in cell migration and offer new insights into RhoA and Rac1 regulation.

Label-free drug response evaluation of human derived tumor spheroids using three-dimensional dynamic optical coherence tomography

This study aims at demonstrating label-free drug-response-patterns assessment of different tumor spheroids and drug types by dynamic optical coherence tomography (D-OCT). The study involved human breast cancer (MCF-7) and colon cancer (HT-29) spheroids. The MCF-7 and HT-29 spheroids were treated with paclitaxel (Taxol; PTX) and the active metabolite of irinotecan SN-38, respectively. The drugs were applied with 0 (control), 0.1, 1, and 10 μM concentrations and the treatment durations were 1, 3, and 6 days. A swept-source OCT microscope equipped with a repeated raster scanning protocol was used to scan the spheroids. Logarithmic intensity variance (LIV) and late OCT correlation decay speed (OCDS[Formula: see text]) algorithms were used to visualize the tumor spheroid dynamics. LIV and OCDS[Formula: see text] images visualized different response patterns of the two types of spheroids. In addition, spheroid morphology, LIV, and OCDS[Formula: see text] quantification showed different time-courses among the spheroid and drug types. These results may indicate different action mechanisms of the drugs. The results showed the feasibility of D-OCT for the evaluation of drug response patterns of different cell spheroids and drug types and suggest that D-OCT can perform anti-cancer drug testing.

Unlocking the Molecular Secrets of Antifolate Drug Resistance: A Multi-Omics Investigation of the NCI-60 Cell Line Panel

Drug resistance continues to be a significant problem in cancer therapy, leading to relapse and associated mortality. Although substantial progress has been made in understanding drug resistance, significant knowledge gaps remain concerning the molecular underpinnings that drive drug resistance and which processes are unique to certain drug classes. The NCI-60 cell line panel program has evaluated the activity of numerous anticancer agents against many common cancer cell line models and represents a highly valuable resource to study intrinsic drug resistance. Furthermore, great efforts have been undertaken to collect high-quality omics datasets to characterize these cell lines. The current study takes these two sources of data-drug response and omics profiles-and uses a multi-omics investigation to uncover molecular networks that differentiate cancer cells that are sensitive or resistant to antifolates, which is a commonly used class of anticancer drugs. Results from a combination of univariate and multivariate analyses showed numerous metabolic processes that differentiate sensitive and resistant cells, including differences in glycolysis and gluconeogenesis, arginine and proline metabolism, beta-alanine metabolism, purine metabolism, and pyrimidine metabolism. Further analysis using multivariate and integrated pathway analysis indicated purine metabolism as the major metabolic process separating cancer cells sensitive or resistant to antifolates. Additional pathways differentiating sensitive and resistant cells included autophagy-related processes (e.g., phagosome, lysosome, autophagy, mitophagy) and adhesion/cytoskeleton-related pathways (e.g., focal adhesion, regulation of actin cytoskeleton, tight junction). Volcano plot analysis and the receiver operating characteristic (ROC) curves of top selected variables differentiating Q1 and Q4 revealed the importance of genes involved in the regulation of the cytoskeleton and extracellular matrix (ECM). These results provide novel insights toward mechanisms of intrinsic antifolate resistance as it relates to interactions between nucleotide metabolism, autophagy, and the cytoskeleton. These processes should be evaluated in future studies to potentially derive novel therapeutic strategies and personalized treatment approaches to improve antifolate response.

Nucleus Mechanosensing in Cardiomyocytes

Cardiac muscle contraction is distinct from the contraction of other muscle types. The heart continuously undergoes contraction-relaxation cycles throughout an animal's lifespan. It must respond to constantly varying physical and energetic burdens over the short term on a beat-to-beat basis and relies on different mechanisms over the long term. Muscle contractility is based on actin and myosin interactions that are regulated by cytoplasmic calcium ions. Genetic variants of sarcomeric proteins can lead to the pathophysiological development of cardiac dysfunction. The sarcomere is physically connected to other cytoskeletal components. Actin filaments, microtubules and desmin proteins are responsible for these interactions. Therefore, mechanical as well as biochemical signals from sarcomeric contractions are transmitted to and sensed by other parts of the cardiomyocyte, particularly the nucleus which can respond to these stimuli. Proteins anchored to the nuclear envelope display a broad response which remodels the structure of the nucleus. In this review, we examine the central aspects of mechanotransduction in the cardiomyocyte where the transmission of mechanical signals to the nucleus can result in changes in gene expression and nucleus morphology. The correlation of nucleus sensing and dysfunction of sarcomeric proteins may assist the understanding of a wide range of functional responses in the progress of cardiomyopathic diseases.

HIV Infection: Shaping the Complex, Dynamic, and Interconnected Network of the Cytoskeleton

HIV-1 has evolved a plethora of strategies to overcome the cytoskeletal barrier (i.e., actin and intermediate filaments (AFs and IFs) and microtubules (MTs)) to achieve the viral cycle. HIV-1 modifies cytoskeletal organization and dynamics by acting on associated adaptors and molecular motors to productively fuse, enter, and infect cells and then traffic to the cell surface, where virions assemble and are released to spread infection. The HIV-1 envelope (Env) initiates the cycle by binding to and signaling through its main cell surface receptors (CD4/CCR5/CXCR4) to shape the cytoskeleton for fusion pore formation, which permits viral core entry. Then, the HIV-1 capsid is transported to the nucleus associated with cytoskeleton tracks under the control of specific adaptors/molecular motors, as well as HIV-1 accessory proteins. Furthermore, HIV-1 drives the late stages of the viral cycle by regulating cytoskeleton dynamics to assure viral Pr55Gag expression and transport to the cell surface, where it assembles and buds to mature infectious virions. In this review, we therefore analyze how HIV-1 generates a cell-permissive state to infection by regulating the cytoskeleton and associated factors. Likewise, we discuss the relevance of this knowledge to understand HIV-1 infection and pathogenesis in patients and to develop therapeutic strategies to battle HIV-1.

Expression of genes regulating cell division in porcine follicular granulosa cells

BACKGROUND

Cell cycle regulation influences the proliferation of granulosa cells and affects many processes related to ovarian folliclular growth and ovulation. Abnormal regulation of the cell cycle can lead to many diseases within the ovary. The aim of this study was to describe the expression profile of genes within granulosa cells, which are related to the formation of the cytoskeleton, organization of cell organelles inside the cell, and regulation of cell division. Established in vitro primary cultures from porcine ovarian follicle granulosa cells were maintained for 48, 96, 144 h and evaluated via microarray expression analysis.

RESULTS

Analyzed genes were assigned to 12 gene ontology groups "actin cytoskeleton organization", "actin filament organization", "actin filament-based process", "cell-matrix adhesion", "cell-substrate adhesion", "chromosome segregation", "chromosome separation", "cytoskeleton organization", "DNA integrity checkpoint", "DNA replication initiation", "organelle fision", "organelle organization". Among the genes with significantly changed expression, those whose role in processes within the ovary are selected for consideration. Genes with increased expression include (ITGA11, CNN1, CCl2, TPM2, ACTN1, VCAM-1, COL3A1, GSN, FRMD6, PLK2). Genes with reduced expression inlcude (KIF14, TACC3, ESPL1, CDC45, TTK, CDC20, CDK1, FBXO5, NEK2-NIMA, CCNE2). For the results obtained by microarray expressions, quantitative validation by RT-qPCR was performed.

CONCLUSIONS

The results indicated expression profile of genes, which can be considered as new molecular markers of cellular processes involved in signaling, cell structure organization. The expression profile of selected genes brings new insight into regulation of physiological processes in porcine follicular granulosa cells during primary in vitro culture.

Molecular mechanism of VE-cadherin in regulating endothelial cell behaviour during angiogenesis

Vascular endothelial (VE)-cadherin, an endothelium-specific adhesion protein, is found in the junctions between endothelial cells (ECs). It's crucial to maintain the homogeneity of ECs. Keeping and controlling the contact between ECs is essential. In addition to its adhesive function, VE-cadherin plays important roles in vascular development, permeability, and tumour angiogenesis. Signal transfer, cytoskeletal reconstruction, and contractile integrating, which are crucial for constructing and maintaining monolayer integrity as well as for repair and regeneration, are the foundation of endothelial cell (EC) junctional dynamics. The molecular basis of adhesion junctions (AJs), which are closely related and work with actin filaments, is provided by the VE-cadherin-catenin complex. They can activate intracellular signals that drive ECs to react or communicate structural changes to junctions. An increasing number of molecules, including the vascular endothelial growth factor receptor 2 (VEGFR2) and vascular endothelial protein tyrosine phosphatase (VE-PTP), have been connected to VE-cadherin in addition to the conventional VE-cadherin-catenin complex. This review demonstrates significant progress in our understanding of the molecular mechanisms that affect VE-cadherin's function in the regulation of EC behaviour during angiogenesis. The knowledge of the molecular processes that control VE-cadherin's role in the regulation of EC behaviour during angiogenesis has recently advanced, as shown in this review.

From the membrane to the nucleus: mechanical signals and transcription regulation

Mechanical forces drive and modulate a wide variety of processes in eukaryotic cells including those occurring in the nucleus. Relevantly, forces are fundamental during development since they guide lineage specifications of embryonic stem cells. A sophisticated macromolecular machinery transduces mechanical stimuli received at the cell surface into a biochemical output; a key component in this mechanical communication is the cytoskeleton, a complex network of biofilaments in constant remodeling that links the cell membrane to the nuclear envelope. Recent evidence highlights that forces transmitted through the cytoskeleton directly affect the organization of chromatin and the accessibility of transcription-related molecules to their targets in the DNA. Consequently, mechanical forces can directly modulate transcription and change gene expression programs. Here, we will revise the biophysical toolbox involved in the mechanical communication with the cell nucleus and discuss how mechanical forces impact on the organization of this organelle and more specifically, on transcription. We will also discuss how live-cell fluorescence imaging is producing exquisite information to understand the mechanical response of cells and to quantify the landscape of interactions of transcription factors with chromatin in embryonic stem cells. These studies are building new biophysical insights that could be fundamental to achieve the goal of manipulating forces to guide cell differentiation in culture systems.

Functional Diversity of Mammalian Small Heat Shock Proteins: A Review

The small heat shock proteins (sHSPs), whose molecular weight ranges from 12∼43 kDa, are members of the heat shock protein (HSP) family that are widely found in all organisms. As intracellular stress resistance molecules, sHSPs play an important role in maintaining the homeostasis of the intracellular environment under various stressful conditions. A total of 10 sHSPs have been identified in mammals, sharing conserved α-crystal domains combined with variable N-terminal and C-terminal regions. Unlike large-molecular-weight HSP, sHSPs prevent substrate protein aggregation through an ATP-independent mechanism. In addition to chaperone activity, sHSPs were also shown to suppress apoptosis, ferroptosis, and senescence, promote autophagy, regulate cytoskeletal dynamics, maintain membrane stability, control the direction of cellular differentiation, modulate angiogenesis, and spermatogenesis, as well as attenuate the inflammatory response and reduce oxidative damage. Phosphorylation is the most significant post-translational modification of sHSPs and is usually an indicator of their activation. Furthermore, abnormalities in sHSPs often lead to aggregation of substrate proteins and dysfunction of client proteins, resulting in disease. This paper reviews the various biological functions of sHSPs in mammals, emphasizing the roles of different sHSPs in specific cellular activities. In addition, we discuss the effect of phosphorylation on the function of sHSPs and the association between sHSPs and disease.

Cytoskeleton remodeling mediated by circRNA-YBX1 phase separation suppresses the metastasis of liver cancer

Metastasis, especially intrahepatic, is a major challenge for hepatocellular carcinoma (HCC) treatment. Cytoskeleton remodeling has been identified as a vital process mediating intrahepatic spreading. Previously, we reported that HCC tumor adhesion and invasion were modulated by circular RNA (circRNA), which has emerged as an important regulator of various cellular processes and has been implicated in cancer progression. Here, we uncovered a nuclear circRNA, circASH2, which is preferentially lost in HCC tissues and inhibits HCC metastasis by altering tumor cytoskeleton structure. Tropomyosin 4 (TPM4), a critical binding protein of actin, turned out to be the major target of circASH2 and was posttranscriptionally suppressed. Such regulation is based on messenger RNA (mRNA)/precursormRNA splicing and degradation process. Furthermore, liquid-liquid phase separation of nuclear Y-box binding protein 1 (YBX1) enhanced by circASH2 augments TPM4 transcripts decay. Together, our data have revealed a tumor-suppressive circRNA and, more importantly, uncovered a fine regulation mechanism for HCC progression.

Staphylococcal Enterotoxin C2 Mutant-Induced Antitumor Immune Response Is Controlled by CDC42/MLC2-Mediated Tumor Cell Stiffness

As a biological macromolecule, the superantigen staphylococcal enterotoxin C2 (SEC2) is one of the most potent known T-cell activators, and it induces massive cytotoxic granule production. With this property, SEC2 and its mutants are widely regarded as immunomodulating agents for cancer therapy. In a previous study, we constructed an MHC-II-independent mutant of SEC2, named ST-4, which exhibits enhanced immunocyte stimulation and antitumor activity. However, tumor cells have different degrees of sensitivity to SEC2/ST-4. The mechanisms of immune resistance to SEs in cancer cells have not been investigated. Herein, we show that ST-4 could activate more powerful human lymphocyte granule-based cytotoxicity than SEC2. The results of RNA-seq and atomic force microscopy (AFM) analysis showed that, compared with SKOV3 cells, the softer ES-2 cells could escape from SEC2/ST-4-induced cytotoxic T-cell-mediated apoptosis by regulating cell softness through the CDC42/MLC2 pathway. Conversely, after enhancing the stiffness of cancer cells by a nonmuscle myosin-II-specific inhibitor, SEC2/ST-4 exhibited a significant antitumor effect against ES-2 cells by promoting perforin-dependent apoptosis and the S-phase arrest. Taken together, these data suggest that cell stiffness could be a key factor of resistance to SEs in ovarian cancer, and our findings may provide new insight for SE-based tumor immunotherapy.