Cell Behavior Research Articles

HIF-1α and adaptor protein LIM and senescent cell antigen-like domains protein 1 axis promotes tubulointerstitial fibrosis by interacting with vimentin in angiotensin II-induced hypertension.

Activation of the renin-angiotensin system, as a hallmark of hypertension and chronic kidney diseases (CKD) is the key pathophysiological factor contributing to the progression of tubulointerstitial fibrosis. LIM and senescent cell antigen-like domains protein 1 (LIMS1) plays an essential role in controlling of cell behaviour through the formation of complexes with other proteins. Here, the function and regulation of LIMS1 in angiotensin II (Ang II)-induced hypertension and tubulointerstitial fibrosis was investigated. C57BL/6 mice were treated with Ang II to induce tubulointerstitial fibrosis. Hypoxia-inducible factor-1α (HIF-1α) renal tubular-specific knockout mice or LIMS1 knockdown AAV was used to investigate their effects on Ang II-induced renal interstitial fibrosis. In vitro, HIF-1α or LIMS1 was knocked down or overexpressed in HK2 cells after exposure to Ang II. Increased expression of tubular LIMS1 was observed in human kidney with hypertensive nephropathy and in murine kidney from Ang II-induced hypertension model. Tubular-specific knockdown of LIMS1 ameliorated Ang II-induced tubulointerstitial fibrosis in mice. Furthermore, we demonstrated that LIMS1 was transcriptionally regulated by HIF-1α in tubular cells and that tubular HIF-1α knockout ameliorates LIMS1-mediated tubulointerstitial fibrosis. In addition, LIMS1 promotes Ang II-induced tubulointerstitial fibrosis by interacting with vimentin. We conclude that HIF-1α transcriptionally regulated LIMS1 plays a central role in Ang II-induced tubulointerstitial fibrosis through interacting with vimentin. Our finding represents a new insight into the mechanism of Ang II-induced tubulointerstitial fibrosis and provides a novel therapeutic target for progression of CKD.

Mechanochemical dynamics of collective cells and hierarchical topological defects in multicellular lumens.

Collective cell dynamics is essential for tissue morphogenesis and various biological functions. However, it remains incompletely understood how mechanical forces and chemical signaling are integrated to direct collective cell behaviors underlying tissue morphogenesis. Here, we propose a three-dimensional (3D) mechanochemical theory accounting for biochemical reaction-diffusion and cellular mechanotransduction to investigate the dynamics of multicellular lumens. We show that the interplay between biochemical signaling and mechanics can trigger either pitchfork or Hopf bifurcation to induce diverse static mechanochemical patterns or generate oscillations with multiple modes both involving marked mechanical deformations in lumens. We uncover the crucial role of mechanochemical feedback in emerging morphodynamics and identify the evolution and morphogenetic functions of hierarchical topological defects including cell-level hexatic defects and tissue-level orientational defects. Our theory captures the common mechanochemical traits of collective dynamics observed in experiments and could provide a mechanistic context for understanding morphological symmetry breaking in 3D lumen-like tissues.

Zebrafish Scale Regeneration In Toto and Ex Vivo Culture of Scales.

Skeletal diseases are often complex in their etiology and affect millions of people worldwide. Due to the aging population, there is a need for new therapeutics that could ease the burden on healthcare systems. As these diseases are complex, it is difficult and expensive to accurately model bone pathophysiology in a lab setting. The challenge for the field is to establish a cost-effective, biologically relevant platform for modeling bone disease that can be used to test potential therapeutic compounds. Such a platform should ideally allow dynamic visualization of cell behaviors of bone-building osteoblasts and bone-degrading osteoclasts acting in their mineralized matrix environment. Zebrafish are increasingly used as models due to the availability of genetic tools, including transgenic reporter lines, and the fact that some skeletal tissues (including the scales) remain translucent to adulthood, allowing dynamic imaging options. Since zebrafish scales have both osteoblasts and osteoclasts and are highly abundant, they provide an easily accessible and abundantly available resource of independent bone units. Moreover, once removed, adult zebrafish scales fully regenerate, therefore offering a way to study the spatiotemporal growth of mineralized tissue in vivo. Here, we detail protocols for harvesting and tracking the regeneration of the scales. Lastly, a protocol for stable culture of scales ex vivo for a week and following the healing response after controlled damage to the mineralized matrix of the scale over time is also presented.

Effects of Different Surface Functionalizations of Silica Nanoparticles on Mesenchymal Stem Cells.

Physicochemical properties of nanoparticles, such as particle size, surface charge, and particle shape, have a significant impact on cell activities. However, the effects of surface functionalization of nanoparticles with small chemical groups on stem cell behavior and function remain understudied. Herein, we incorporated different chemical functional groups (amino, DETA, hydroxyl, phosphate, and sulfonate with charges of +9.5, + 21.7, -14.1, -25.6, and -37.7, respectively) to the surface of inorganic silica nanoparticles. To trace their effects on mesenchymal stem cells (MSCs) of rat bone marrow, these functionalized silica nanoparticles were used to encapsulate Rhodamine B fluorophore dye. We found that surface functionalization with positively charged and short-chain chemical groups facilitates cell internalization and retention of nanoparticles in MSCs. The endocytic pathway differed among functionalized nanoparticles when tested with ion-channel inhibitors. Negatively charged nanoparticles mainly use lysosomal exocytosis to exit cells, while positively charged nanoparticles can undergo endosomal escape to avoid scavenging. The cytotoxic profiles of these functionalized silica nanoparticles are still within acceptable limits and tolerable. They exerted subtle effects on the actin cytoskeleton and migration ability. Last, phosphate-functionalized nanoparticles upregulate osteogenesis-related genes and induce osteoblast-like morphology, implying that it can direct MSCs lineage specification for bone tissue engineering. Our study provides insights into the rational design of biomaterials for effective drug delivery and regenerative medicine.

Abstract PO4-28-02: Adipocyte Progenitor-Mediated Effects on Mammary Cancer Cells

Abstract Treatment challenges in breast cancer arise from significant heterogeneity found within breast tumors and the surrounding microenvironment. The tumor microenvironment presents a complex ecosystem which comprises diverse stromal cells including immune, endothelial and fibroblast cell lineages and the extracellular matrix that support tumor progression. Adipocytes represent an abundant cell population in the normal breast and prior studies have reported a crosstalk between adipocytes and mammary cancer cells. De-differentiation of adipocytes into adipocyte progenitor-like cells is linked to a pro-tumorigenic microenvironment in mouse mammary tumors. We have previously demonstrated that adipocyte progenitors in the murine mammary stroma have the capacity to generate epithelial lineages during mammary epithelial growth. The influence of adipocyte progenitors in the mammary tumor microenvironment is not known. In this study, we investigated the effects of adipocyte progenitors on mammary cancer cells and their interactions using the 3T3-L1 adipocyte precursor (AP) cell line and the EO771 syngeneic mammary cancer (MCa) cell line. AP and MCa cell lines were co-cultured, after which MCa cell growth, invasion and migration were assessed using established in vitro assays. MCa cells cultured alone were also exposed to AP-conditioned media to determine whether secreted factors derived from APs could modulate MCa cells. AP cells were found to alter the behavior of MCa cells, affecting their cell proliferation, migration, and cellular phenotype. This work infers the potential of adipocyte progenitors to regulate mammary cancer growth and progression, which warrants further investigation into their fate and role in vivo during mammary tumorigenesis. Keywords: breast cancer, adipocyte progenitors, tumor microenvironment Citation Format: Jacqulene Sunder Singh, Purna Joshi, Emma Unger. Adipocyte Progenitor-Mediated Effects on Mammary Cancer Cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-28-02.

Abstract PO4-28-11: Murine Breast Cancer Cell Culture Supernatant Induces CAF-like and TAM-like Traits in Normal Cells

Abstract Several studies in the past have demonstrated the role of cell-to-cell interaction (crosstalk) between tumor cells and normal (nontumorigenic) cells in cancer progression and metastasis. Within the tumor microenvironment (TME), these interactions have a potential to transform the phenotypes and the behaviors of normal cells. Application of the 2D in-vitro cultures has been limited due to its inability to replicate the complex in-vivo TME. Conditioned Medium (CM) obtained from cultured cancer cells contains secreted growth factors that potentially regulate the phenotype and the functionality of normal cells. In this study, a culture of normal murine fibroblast NIH3T3 and macrophage RAW 264.7 cells with conditioned medium (CM) obtained from malignant mammary epithelial 4T1 cells (4T1CM) resulted in an altered phenotype with increased cell viability. 4T1CM treated NIH3T3 and RAW 264.7, in comparison with the respective control cells, resulted in an upregulation of the genes including- α-smooth muscle actin (αSMA), IL-10, CD206, and vascular endothelial growth factor (VEGF). In addition, 4T1.CM treated NIH3T3 showed an EMT phenotype as indicated by the regulation of EMT markers such as, E-cadherin, β-catenin, N-cadherin, and Vimentin. Interestingly, an upregulation of cyclooxygenase-2 (COX-2) and programmed death-ligand 1 (PDL-1) was observed in 4T1CM treated RAW 264.7, a tendency towards exhibiting an inhibitory immune response. Intriguingly, NIH3T3 cells conditioned with 4T1CM demonstrated an upregulation of stemness markers including- sex determining region Y-box 2, and Aldehyde dehydrogenase. Collectively, our study suggested a role for 4T1CM in transforming the normal NIH3T3 and RAW 264.7 into cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs). RNAseq experiments are underway to map differentially expressed genes (DEGs) that potentially regulate the 4T1CM induced transformation of NIH3T3 and RAW 264.7 cells. Furthermore, invitro drug testing in 3D model of these transformed cells to target the pathway intermediates may provide novel therapeutic intervention strategies. Citation Format: Biplov Sapkota, Naveen Chintalaramulu, Abhishek Pandit, Shilpa Thota, Rizwana Begum, Joseph Francis. Murine Breast Cancer Cell Culture Supernatant Induces CAF-like and TAM-like Traits in Normal Cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-28-11.

Abstract PO5-06-11: RPL27A promotes the growth and metastasis of triple negative breast cancer by regulating Ribosome biogenesis

Abstract Background: Ribosome is a complex structure in cells for protein synthesis. It has been considered always have a constant composition. Recent studies have revealed that the Ribosome composition of tumor cells is heterogeneous. The Ribosome protein composition, post-translational modification, rRNA modification, and rRNA variants can lead to the existence of specialized "onco-ribosomes" in tumor cells, which regulates the rate of translation and protein synthesis, and can affect the occurrence and development of tumors significantly. The abnormal expression of multiple Ribosome proteins in triple-negative breast cancer may be the target of its diagnosis and treatment, also, an independent factor in prognosis evaluation. Methods: To learn the expression levels of Ribosome biogenesis related genes in normal breast cells and abnormal breast cells with different pathological subtypes of breast cancer, the following studies have been done: 1. Bioinformatics analysis on TCGA database and single-cell sequencing data; 2. IHC detection on TNBC tissue and adjacent tissues; 3. Determine the expression level of RPL27A in TNBC cells, and analyze the correlation between the expression of RPL27A and clinical information of patients. To explore the effect of RPL27A on Ribosome biogenesis, protein synthesis and other signaling pathways through Proteomics and molecular biology experiments have been designed and tested. The effects of RPL27A on malignant biological behaviors such as proliferation, migration, infiltration, and clonal formation of TNBC cells were studied through cell biology experiments and mouse experiments. Results: The analysis of TCGA database and single-cell sequencing data showed that the RPL27A was significantly increased in TNBC group. Immunohistochemical experiments showed that RPL27A was highly expressed in TNBC tissue and was impressively positively correlated with tumor size, lymph node metastasis, and bone metastasis. There was significantly negatively correlated with overall survival (OS) and disease free survival (DFS). It can be an independent factor for evaluating the prognosis of TNBC. By knocking out RPL27A in TNBC cell line, label free proteomics analysis showed that Ribosome biogenesis, protein synthesis, cell cycle regulation and other signaling pathways were obviously down regulated. Cell biology experiments have implied that the high expression of RPL27A in TNBC promotes cell proliferation, enhances cell migration, infiltration, and cloning ability, leads to more malignant biological behavior of tumor cells. Further research demonstrates that the high expression of RPL27A in TNBC significantly activated the EIF3C signal, cause changes in the composition of Ribosome in TNBC cells, promoted the formation of "onco-ribosomes", and distinctly increased the rate of protein synthesis. The study of PDX mice and Organoid showed that the knock out of RPL27A significantly reduced the growth rate and transfer ability of TNBC. Conclusion: The obvious over expressing of RPL27A in TNBC, which can significantly promote the growth and metastasis of tumor cells by influencing the Ribosome biogenesis process. Citation Format: Weipeng Zhao, Jingyi Zhang, Ye Zhu, Xin Yang, Xichuan Li. RPL27A promotes the growth and metastasis of triple negative breast cancer by regulating Ribosome biogenesis [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-06-11.

Abstract Wrk2-02: Modelling the effects of cell-cell interactions in the tumor microenvironment from single cell variability

Abstract Multicellular programs underly emergent phenotypes in health and disease. Yet, deciphering the functional effects of interactions amongst cell types remains a major challenge. Cells typically send messages to their microenvironment by emitting ligands, which bind to complimentary receptors on the surfaced of target cells; then triggering a change in the behavior of the target cell. Complimentary ligand-receptor-pairs are well annotated and methods have been developed to infer cell-cell interactions from single cell expression data based on their mutual expression. However, these methods do not assess the effect of ligand-receptor-mediated interactions on the microenvironment. Thus, we developed ContactTracing – a fundamentally new, systems level approach that exploits inter- and intra-sample variability to infer ligand effects on gene expression in target (receptor-expressing) cells without prior knowledge of downstream signaling (Nature, 2023). Foundational work towards benchmarking and validation of this method was performed in isogenic breast cancer models distinguished by tumor cell-intrinsic rates of chromosome missegregation (a cellular process called chromosomal instability, or CIN). Through this, we identified tumor ligands emanating from an endoplasmic reticulum (ER)-stress response as potential mediators of immune suppression in chromosomally unstable tumors. Indeed, CIN-induced chronic STING activation led to rapid interferon-selective desensitization and a switch to ER-stress-dependent transcription. Moreover, inhibition of chronic STING - or key mediators of its unfolded protein response to ER-stress - suppressed metastasis in syngeneic models of melanoma, breast and colorectal cancer; validating this innovative methodology and identifying a targetable mediator of cancer metastasis. Citation Format: A. Laughney. Modelling the effects of cell-cell interactions in the tumor microenvironment from single cell variability [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr Wrk2-02.

Effects of Capsaicin on Migration and Alkaline Phosphatase Activity of Dental Pulp Cells.

Dental pulp, a specialized mesenchymal tissue within teeth, is pivotal in dental health and tissue repair. Capsaicin, the primary pungent component of chili peppers, is known for its diverse pharmacological properties. While capsaicin's effects on various cell types have been studied, its impact on dental pulp cells remains relatively unexplored. This study investigated the influence of pure capsaicin extract on dental pulp cell behavior, focusing on cell viability, proliferation, migration, and alkaline phosphatase (ALP) activity. Capsaicin solution was prepared and diluted to various concentrations (1 nM, 0.01 µM, 0.1 µM, 1 µM, 10 µM, and 100 µM), then was tested on rat dental pulp cells (RPC-C2A). Cell viability and proliferation were assessed using the MTT assay. Boyden chamber tests and wound healing were used for evaluating cell migration. The activity of ALP was determined to show cell function during dental pulp repair. The data were analyzed using a one-way analysis of variance or an independent-sample Kruskal-Wallis, followed by multiple comparison tests. Capsaicin of 100 µM exhibited cytotoxicity, whereas those with lower concentrations stimulated cell proliferation. Wound healing assays revealed increased cell migration, particularly when cultured with 1 nM capsaicin (p = 0.002). Boyden chamber assays demonstrated enhanced cell invasion without statistical significance. ALP activity of dental pulp cells increased significantly at 1 nM (p < 0.001) and 1 µM (p = 0.021) capsaicin concentrations, indicating potential dentinogenesis and pulp repair. Capsaicin of lower concentrations, less than 10 µM, is likely to promote proliferation, migration, and ALP activity of dental pulp cells. Our findings offer potential applications for capsaicin as a medication for dental pulp repair.

Abstract PO4-28-03: Investigating the role of extracellular vesicles in tumor-stromal cell interactions in early-stage breast cancer invasion

Abstract Ductal carcinoma in situ (DCIS) is the most common form of early-stage breast cancer. Anywhere from 10%–30% of DCIS cases progress to invasive ductal carcinoma (IDC), resulting in poor prognosis and clinical challenges. Still, the cellular basis of this DCIS transition remains poorly understood. To escape the primary site during local invasion, DCIS cells navigate through the extracellular matrix and a diverse collection of stromal cells in the surrounding microenvironment. Cancer associated fibroblasts (CAFs) are a stromal cell population that can facilitate tumor invasion in part through extracellular matrix remodeling. CAFs at the primary tumor are largely derived from fibroblasts that have been reprogrammed to an activated state. In addition, several physical, cellular and metabolic changes within the tumor microenvironment (TME) are known to alter the breast cancer invasive capacity. Here we report that forced inhibition of cell invasion, by blocking the activity of known regulators of cell invasion in the ductal epithelial cell line, MCF10ADCIS.com, (herein referred to as DCIS.com), is accompanied by a marked reduction in extracellular vesicle (EV) secretion. Moreover, we show that DCIS.com cells conditioned with secreted EVs exhibit significantly enhanced invasive capacity relative to naïve DCIS.com cells. It is now well documented that breast and other tumor cells release heterogenous populations of EVs that can function as mediators of intercellular communication in the tumor microenvironment. EVs contain a host of bioactive cargo, such as membrane and cytosolic proteins, various RNA species including microRNAs, as well as dsDNA. These shed vesicles may deposit paracrine information and can also be taken up by stromal cells such as fibroblasts causing the recipient cells to undergo phenotypic changes that profoundly impact various facets of tumor progression. Conversely, EVs shed from stromal cells also affect tumor cell behavior. This unique form of intercellular crosstalk helps condition the TME and promotes both invasive and metastatic activity. In this regard, we found that incubation of human fibroblast cells with EVs shed from tumor cells leads to a loss of SMAD-7 expression (previously implicated in CAF reprogramming), and this loss is abrogated when shedding cells are depleted of miR-21 or regulators of miRNA trafficking to surface-derived EVs. Further, using spheroid invasion assays we demonstrate that fibroblast-derived EVs facilitate directed and leader-follower modes of migration, suggesting the possibility that CAFs likely deposit chemotactic cues to promote directional movement in DCIS. While the regulation of this behavior is still being explored, our observations suggest that EVs, in addition to facilitating distal proteolysis, may also support both autocrine and paracrine signaling during cell invasion. Finally, we are investigating how these pathways may also contribute to the ‘field effect’ of breast cancerization, a poorly understood process that introduces genetic and phenotypic changes in normal epithelia, potentially contributing to disease onset and/or recurrence. Citation Format: Madison Schmidtmann, Grace Richmond, Shireen Jayman, James Clancy, Crislyn D'Souza-Schorey. Investigating the role of extracellular vesicles in tumor-stromal cell interactions in early-stage breast cancer invasion [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-28-03.

Engineered Cell Membrane-Coated Nanoparticles: New Strategies in Glioma Targeted Therapy and Immune Modulation.

Gliomas, the most prevalent primary brain tumors, pose considerable challenges due to their heterogeneity, intricate tumor microenvironment (TME), and blood-brain barrier (BBB), which restrict the effectiveness of traditional treatments like surgery and chemotherapy. This review provides an overview of engineered cell membrane technologies in glioma therapy, with a specific emphasis on targeted drug delivery and modulation of the immune microenvironment. This study investigates the progress in engineered cell membranes, encompassing physical, chemical, and genetic alterations, to improve drug delivery across the BBB and effectively target gliomas. The examination focuses on the interaction of engineered cell membrane-coated nanoparticles (ECM-NPs) with the TME in gliomas, emphasizing their potential to modulate glioma cell behavior and TME to enhance therapeutic efficacy. The review further explores the involvement of ECM-NPs in immunomodulation techniques, highlighting their impact on immune reactions. While facing obstacles related to membrane stability and manufacturing scalability, the review outlines forthcoming research directions focused on enhancing membrane performance. This review underscores the promise of ECM-NPs in surpassing conventional therapeutic constraints, proposing novel approaches for efficacious glioma treatment.

Multiplexed Imaging Mass Cytometry Analysis Characterizes the Vascular Niche in Pancreatic Cancer.

Oncogenesis and progression of pancreatic ductal adenocarcinoma (PDAC) is driven by complex interactions between the neoplastic component and the tumor microenvironment (TME), which includes immune, stromal, and parenchymal cells. In particular, most PDACs are characterized by a hypovascular and hypoxic environment that alters tumor cell behavior and limits the efficacy of chemotherapy and immunotherapy. Characterization of the spatial features of the vascular niche could advance our understanding of inter- and intra-tumoral heterogeneity in PDAC. Here, we investigated the vascular microenvironment of PDAC by applying imaging mass cytometry using a 26-antibody panel on 35 regions of interest (ROIs) across 9 patients, capturing over 140,000 single cells. The approach distinguished major cell types, including multiple populations of lymphoid and myeloid cells, endocrine cells, ductal cells, stromal cells, and endothelial cells. Evaluation of cellular neighborhoods identified 10 distinct spatial domains, including multiple immune and tumor-enriched environments as well as the vascular niche. Focused analysis revealed differential interactions between immune populations and the vasculature and identified distinct spatial domains wherein tumor cell proliferation occurs. Importantly, the vascular niche was closely associated with a population of CD44-expressing macrophages enriched for a pro-angiogenic gene signature. Together, this study provides insights into the spatial heterogeneity of PDAC and suggests a role for CD44-expressing macrophages in shaping the vascular niche.

Chiral Arginine Modified Electrospun Membrane for Enhancing Tendon Healing

AbstractTendon injury is a common motor system disease, impairing joint mobility, and lowering quality of life. Once damaged, tendon has a limited capacity for regeneration. Clinically, available therapeutic strategies have not achieved satisfactory outcomes. Chiral biomaterials can effectively regulate cell behaviors and tissue healing, but have not been applied to injured tendon yet. Here, chiral arginine is attached to electrospun membrane to fabricate chiral scaffolds. L‐chiral scaffold, rather than D‐chiral or R‐chiral scaffold, promotes cell adhesion, proliferation, and tenogenic differentiation. The vinculin/FAK/YAP pathway is discovered to have a significant impact on the processes mentioned above. Additionally, L‐arginine efficiently eliminates reactive oxygen species (ROS) and generates nitric oxide (NO), safeguarding tendon stem/progenitor cells (TSPCs) against oxidative stress. The use of L‐chiral scaffold in a rat model of Achilles tendon injury increases the expression of markers related to tendons and the deposition of collagen. Moreover, L‐chiral scaffold improves tendon structural, functional, and mechanical properties. This L‐chiral scaffold comprehensively enhances tendon healing, providing a promising therapeutic strategy for tendon injury. As a simple and effective method, modification by chiral molecules enriches biomaterial functions and offers a novel option for tissue regeneration.

A Spontaneous In Situ Thiol-Ene Crosslinking Hydrogel with Thermo-Responsive Mechanical Properties.

The thermo-responsive behavior of Poly(N-isopropylacrylamide) makes it an ideal candidate to easily embed cells and allows the polymer mixture to be injected. However, P(NiPAAm) hydrogels possess minor mechanical properties. To increase the mechanical properties, a covalent bond is introduced into the P(NIPAAm) network through a biocompatible thiol-ene click-reaction by mixing two polymer solutions. Co-polymers with variable thiol or acrylate groups to thermo-responsive co-monomer ratios, ranging from 1% to 10%, were synthesized. Precise control of the crosslink density allowed customization of the hydrogel's mechanical properties to match different tissue stiffness levels. Increasing the temperature of the hydrogel above its transition temperature of 31 °C induced the formation of additional physical interactions. These additional interactions both further increased the stiffness of the material and impacted its relaxation behavior. The developed optimized hydrogels reach stiffnesses more than ten times higher compared to the state of the art using similar polymers. Furthermore, when adding cells to the precursor polymer solutions, homogeneous thermo-responsive hydrogels with good cell viability were created upon mixing. In future work, the influence of the mechanical micro-environment on the cell's behavior can be studied in vitro in a continuous manner by changing the incubation temperature.

AJAP1 Regulates Human Epithelial Cell Behaviors Required for Epicardium and EPDC Formation During Cardiac Development

Introduction: The epicardium forms the outermost layer of the heart. It is composed of a single layer of specialized epithelial cells that make important cellular contributions to cardiovascular development. During embryonic development, the epicardium is a source of multipotent progenitor cells, growth factors and extracellular matrix (ECM) components. The epicardium gives rise to multipotent epicardial-derived cells (EPDCs) which undergo epithelial-to-mesenchymal transition and differentiate into non-myocyte cardiac lineages. It is also a source of paracrine signals essential for myocardial growth and coronary vessel formation that become dormant after gestation. Adult epicardial cells can be reactivated in response to myocardial injury or ischemia to express a fetal gene program for regenerative cardiac repair. The drive to harness epicardial cells for cardiac regeneration is tethered to its roles in cardiovascular development. Thus, it is necessary to identify molecules that regulate epicardial cell behaviors required for epicardium formation and EPDC differentiation. Using our Tbx5-deficient mouse model of defective epicardium formation ( Tbx5epi−/−), we identified a transcript that is novel to the heart. Adherens junction associated protein 1 is a cell adhesion molecule that is encoded by the AJAP1 transcript which was downregulated in Tbx5epi−/− mice with impaired epicardium formation. Our preliminary studies revealed that AJAP is expressed in epithelial cells of the epicardium during heart development. Silencing of AJAP1 in primary cultured human epithelial cells reduces their ability to migrate. A role for AJAP1 in the epicardium during cardiac development remains to be identified. Study Objective: This study was designed to investigate the impact of AJAP1 on epithelial cell functions that are required for formation of the epicardium and differentiation of EPDCs. Methods: Studies were conducted in a primary human epithelial cell line, HMEpiC, which served as an in vitro model system to examine the contributions of AJAP1 to epithelial cell behaviors. HMEpiCs were transfected with small interfering RNAs (siRNAs) targeting either human AJAP1 to knock down its endogenous expression or a non-targeting negative control siRNA. AJAP1 knockdown was confirmed by quantitative PCR and immunofluorescence. We conducted assays on control and AJAP1 knockdown (KD) cells to examine the effects on epithelial cell behaviors contributing to epicardium formation and EPDC differentiation. This included analysis of cell proliferation, apoptosis, and adhesion to extracellular matrices. Results: Endogenous AJAP1 mRNA expression was reduced significantly by siRNA-mediated knockdown in human epithelial cells. We observed changes in cell morphology that correlated with a significant increase in apoptosis in AJAP1 KD cells compared to negative control cells. Proliferation of HMEpiCs was unchanged by AJAP1 knockdown. Also, we observed a significant increase in the adhesion of AJAP1 KD cells to certain extracellular matrices versus control cells. Conclusion: These findings provide evidence for the AJAP1 cell adhesion molecule to regulate epithelial cell behaviors that are crucial to formation of the epicardium and differentiation of EPDCs during cardiac development. PCOM Center for Chronic Disorders of Aging; PCOM Division of Research. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Performance benchmark of different cell clones in discontinuous and continuous bioprocesses reveals critical impact of cellular diameter

Therapeutic proteins such as monoclonal antibodies are usually manufactured either in continuous processes such as steady-state perfusion or in discontinuous processes like fed-batch (FB). Thereby, both process formats have fundamentally different requirements for the utilized cell factories. This poses a problem as common cell line development programs are designed to select cell clones to perform well in FB cultivation. The aim of this study was to identify critical and easy to access cell line attributes for each process format and with that for the transfer of clones from fed-batch to perfusion. As a result, increased cell-volume specific productivity could be identified as beneficial within the FB not only impacting performance but as well diminishing media utilization and host-cell-proteins level. Within the perfusion, a stable cell diameter was identified as major beneficial characteristic, positively influencing cell viability, metabolite and glycan profile, as well as equipment utilization. Consistent with this, our data suggest that the inclusion of cell volume in the screening parameters is important for clone selection for both process formats and can lead to improved process design and robust cell line process transfer. Overall, this work gives valuable new insights in cell behaviour across discontinuous and continuous process formats to improve clone cell selection for both process strategies and streamline the process transfer from discontinuous towards continuous.

Noncanonical functions of telomerase and telomeres in viruses-associated cancer.

The cause of cancer is attributed to the uncontrolled growth and proliferation of cells resulting from genetic changes and alterations in cell behavior, a phenomenon known as epigenetics. Telomeres, protective caps on the ends of chromosomes, regulate both cellular aging and cancer formation. In most cancers, telomerase is upregulated, with the telomerase reverse transcriptase(TERT) enzyme and telomerase RNA component(TERC) RNA element contributing to the maintenance of telomere length. Additionally, it is noteworthy that two viruses, human papillomavirus (HPV) and Epstein-Barr virus (EBV), utilize telomerase for their replication or persistence in infected cells. Also, TERT and TERC may play major roles in cancer not related to telomere biology. They are involved in the regulation of gene expression, signal transduction pathways, cellular metabolism, or even immune response modulation. Furthermore, the crosstalk between TERT, TERC, RNA-binding proteins, and microRNAs contributes to a greater extent to cancer biology. To understand the multifaceted roles played by TERT and TERC in cancer and viral life cycles, and then to develop effective therapeutic strategies against these diseases, are fundamental for this goal. By investigating deeply, the complicated mechanisms and relationships between TERT and TERC, scientists will open the doors to new therapies. In its analysis, the review emphasizes the significance of gaining insight into the multifaceted roles that TERT and TERC play in cancer pathogenesis, as well as their involvement in the viral life cycle for designing effective anticancer therapy approaches.

Tuning multiple enzyme-like activities by metal doping for identification and quantitation of antioxidants in cosmetics

Inspired by the hydrolysis behaviors of skin cells, we exquisitely designed and synthesized a class of hydrolase mimics to develop an analytical method that can both identify and quantity antioxidant components in skin-whitening cosmetics, including ascorbic acid (AA) and its glycoside and phosphate derivatives. A series of ultra-thin Cu1-xMnxO2 or Fe1-yMnyO2 with rich acid-base pairs were prepared via chemical deposition and in-situ CuI/FeII self-assembly. H218O and D216O isotopic labeling studies and density function theory (DFT) calculations were adopted to analyze the cleaving sites of ascorbyl phosphate (AAL)/ascorbyl glucoside (AAP) and confirm that H2O was involved in the new bonds. In-situ DRIFT NH3-IR and −TPD further confirmed that the Fe- or Cu-substitution could increase the quantity and strength of Brønsted and Lewis acid sites. A cascade catalytic fluorescence sensor was designed for selective recognition or quantification of AA and its derivatives, which presents ultra-high-precision (≤2.5 %), stability, and selectivity in testing the target ingredients of five cosmetics from the market. Our nanozymes exhibit higher catalytic efficiency of 17.1 s−1 for AA, 8.42 s−1 for AAL, and 3.32 s−1 for AAP, which are 5.6 ∼ 32.8-fold higher than those of their mimic proteases. This work provides a controllable methodology to design hydrolytic nanozymes, which sheds light on biomimetic engineering and paves the way for breakthroughs in cosmetics industrial applications in the future.

Titanium alloys for orthopedic applications: A review on the osteointegration induced by physicomechanical stimuli

Titanium (Ti) alloys have been widely applied clinically due to their good biocompatibility, corrosion resistance and mechanical stability. However, how to improve the weak osteointegration caused by their intrinsic bio-inertness has been a long-standing puzzle. Osteogenic-related cells, endothelial cells (ECs) and macrophages are the main cells involved in osteointegration. In recent years, surface topography based on Ti alloys, which mimics the topographical cues of the extracellular matrix (ECM), has been confirmed to precisely regulate these cells' fate to improve osteointegration. More importantly, while serving as a physicomechanical stimuli, topographic surface modification is considered more biosafe and stable than biochemical cues. Nevertheless, how different topographic modifications affect cell behavior and the specific mechanisms involved remain elusive. In this review, we highlight the regulation of surface topography based on Ti alloys on the behaviors of bone repair-related cells, such as osteogenic-related cells, ECs and macrophages, and summarize the activated intracellular mechanotransduction pathways, which aims to provide basis and support for further research on osteointegration of Ti alloys.

GLYR1 transcriptionally regulates PER3 expression to promote the proliferation and migration of multiple myeloma

Period circadian regulator 3 (PER3) functions as a tumor suppressor in various cancers. However, the role of PER3 in multiple myeloma (MM) has not been reported yet. Through this study, we aimed to investigate the potential role of PER3 in MM and the underlying mechanisms. RT-qPCR and western blotting were used to determine the mRNA and protein expression levels of PER3. Glyoxylate reductase 1 homolog (GLYR1) was predicted to be a transcription factor of PER3. The binding sites of GLYR1 on the promoter region of PER3 were analyzed using UCSC and confirmed using luciferase and chromatin immunoprecipitation assays. Viability, apoptosis, and metathesis were determined using CCK-8, colony formation, TUNEL, and transwell assays. We found that PER3 expression decreased in MM. Low PER3 levels may predict poor survival rates; PER3 overexpression suppresses the viability and migration of MM cells and promotes apoptosis. Moreover, GLYR1 transcriptionally activates PER3, and the knockdown of PER3 alleviates the effects of GLYR1 and induces its malignant behavior in MM cells. To conclude, GLYR1 upregulates PER3 and suppresses the aggressive behavior of MM cells, suggesting that GLYR1/PER3 signaling may be a potential therapeutic target for MM.