Regulation of cardiomyocyte adhesion and mechanosignalling through distinct nanoscale behaviour of integrin ligands mimicking healthy or fibrotic extracellular matrix

Rigid and soft substrates respectively promote the myocardial differentiation and maturation of human embryonic stem cells using elastic PDMS with thick synthetic coating

Cardiovascular disease is the predominant cause of mortality and severe disability. Cardiomyocytes (CMs) derived from human embryonic stem cells (hESCs) have good application prospects for treating this disease. Unfortunately, CMs generated via current methods are relatively immature, as proven by defects such as sarcomer-like structures, calcium processing capacity and mitochondrial maturity. Therefore, in this study, tunable PDMS substrates that modified with sufficiently thick synthetic coatings were prepared to regulate both the myocardial differentiation of hESCs and subsequent maturation. Surprisingly, the effect of substrate elasticity on the critical attachment of hESCs and hESC-CMs vanished when common Matrigel coatings were used, but apparent differences were detected in the synthetic group. Rigid substrates promoted the adhesion of hESCs but not hESC-CMs. Moreover, the PDMS substrates with the highest hardness remarkably promoted the myocardial differentiation of hESCs, which was even better than that of the rigid plate group. The softest PDMS achieved the best performance among the groups in terms of the maturation of hESC-CMs, as confirmed by enhanced functional, metabolic, and ultrastructural maturation. This study reveals the real impact of an elastic substrate on the adhesion, differentiation, and maturation of hESC-CMs, which has value for accelerating the development of clinically applicable mature hESC-CMs with high induction efficiency.

Signals from the extracellular matrix: Region- and sex-specificity in cardiac aging

During aging, the cardiac extracellular matrix (ECM) undergoes gradual remodeling that reduces the heart's ability to function. Specific ECM changes cause alterations in cellular signaling pathways, eliciting maladaptive responses. Here, we provide insight into the current knowledge of how age-specific ECM changes contribute to altered ligand-receptor interactions, dysregulated mechanotransduction, and the propagation of pro-fibrotic signaling cascades that underpin dysfunction. We also highlight regional and sex differences that new biomolecular and bioengineered technologies have recently uncovered. We call for new biomaterial strategies that mimic spatiotemporal and sex-specific ECM alterations to equip researchers with the tools to unravel complex cellular signaling events. We believe this can be achieved through interdisciplinary cooperation amongst researchers spanning matrix biology, biomaterials, spatial omics, and biomedical engineering.

The role and regulation of integrins in cell migration and invasion

Integrin receptors are the main molecular link between cells and the extracellular matrix (ECM) as well as mediating cell-cell interactions. Integrin-ECM binding triggers the formation of heterogeneous multi-protein assemblies termed integrin adhesion complexes (IACs) that enable integrins to transform extracellular cues into intracellular signals that affect many cellular processes, especially cell motility. Cell migration is essential for diverse physiological and pathological processes and is dysregulated in cancer to favour cell invasion and metastasis. Here, we discuss recent findings on the role of integrins in cell migration with a focus on cancer cell dissemination. We review how integrins regulate the spatial distribution and dynamics of different IACs, covering classical focal adhesions, emerging adhesion types and adhesion regulation. We discuss the diverse roles integrins have during cancer progression from cell migration across varied ECM landscapes to breaching barriers such as the basement membrane, and eventual colonization of distant organs.

Selective placement of functionalised DNA origami via thermal scanning probe lithography patterning

Here we present a nanopatterning strategy utilising thermal scanning probe lithography (t-SPL) for the precise organisation of DNA origami into nanoarrays. The aim of this approach is to demonstrate control in the fabrication of nanoarray platforms exhibiting single-molecule accuracy. Combining the inherent programmability of DNA origami structures with t-SPL nanopatterning, we demonstrated the controlled immobilisation on surfaces of functionalised DNA origami - as proof of concept we employed gold nanoparticles (AuNPs) and quantum dots (QDs) - at predefined positions and in nanoarray configurations. This method holds great potential for the construction of hetero-functionalised biomolecular nanoarrays with single-molecule control, with applications in bionanotechnology and (nano)materials science.

Creation of Grooved Tissue Engineering Scaffolds from Architectured Multilayer Polymer Composites by a Tuneable One-Step Degradation Process

The surface properties of biomaterials interact directly with biological systems, influencing cellular responses, tissue integration, and biocompatibility. Surface topography plays a critical role in cardiac tissue engineering by affecting electrical conductivity, cardiomyocyte alignment, and contractile function. Current methods for controlling surface properties and topography in cardiac tissue engineering scaffolds are limited, expensive, and lack precision. This study introduces a low-cost, one-step degradation process to create scaffolds with well-defined micro-grooves from multilayered 3D printed poly(lactic acid)/thermoplastic polyurethane composites. The approach provides control over erosion rate and surface morphology, allowing easy tuning of scaffold topographical cues for tissue engineering applications. The findings reported in this study provide a library of easily tuneable scaffold topographical cues. A strong dependence of neonatal rat cardiomyocyte (NRCM) contact guidance with the multilayers' dimension and shape in partially degraded polylactic acid (PLA)/thermoplastic polyurethane (TPU) samples is observed. NRCMs cultured on samples with a layer thickness of 13 ± 2 µm and depth of 4.7 ± 0.2 µm demonstrate the most regular contractions. Hence, the proposed fabrication scheme can be used to produce a new generation of biomaterials with excellent controllability determined by multilayer thickness, printing parameters, and degradation treatment duration.

Hyaluronic acid-based hydrogels with tunable mechanics improved structural and contractile properties of cells

Extracellular matrix (ECM) regulates cellular responses through mechanotransduction. The standard approach of in vitro culturing on plastic surfaces overlooks this phenomenon, so there is a need for biocompatible materials that exhibit adjustable mechanical and structural properties, promote cell adhesion and proliferation at low cost and for use in 2D or 3D cell cultures. This study presents a new tunable hydrogel system prepared from high-molecular hyaluronic acid (HA), Bovine serum albumin (BSA), and gelatin cross-linked using EDC/NHS. Hydrogels with Young's moduli (E) ranging from subunit to units of kilopascals were prepared by gradually increasing HA and BSA concentrations. Concentrated high-molecular HA network led to stiffer hydrogel with lower cluster size and swelling capacity. Medium and oxygen diffusion capability of all hydrogels showed they are suitable for 3D cell cultures. Mechanical and structural changes of mouse embryonic fibroblasts (MEFs) on hydrogels were compared with cells on standard cultivation surfaces. Experiments showed that hydrogels have suitable mechanical and cell adhesion capabilities, resulting in structural changes of actin filaments. Lastly, applying hydrogel for a more complex HL-1 cell line revealed improved mechanical and electrophysiological contractile properties.

All the small things: Nanoscale matrix alterations in aging tissues

Cellular aging stems from multifaceted intra- and extracellular molecular changes that lead to the gradual deterioration of biological function. Altered extracellular matrix (ECM) properties that include biochemical, structural, and mechanical perturbations direct cellular- and tissue-level dysfunction. With recent advancements in high-resolution imaging modalities and nanomaterial strategies, the importance of nanoscale ECM features has come into focus. Here, we provide an updated window into micro- to nano-scale ECM properties that are altered with age and in age-related disease, and the impact these altered small-scale ECM properties have on cellular function. We anticipate future impactful research will incorporate nanoscale ECM features in the design of new biomaterials and call on the tissue biology field to work collaboratively with the nanomaterials community.

Rapid Regulation of Cardiomyocytes Adhesion on Substrates with Varied Modulus via Mechanical Cues

In-depth understanding of the mechanisms underlying the adhesion of myocardial cells holds significant importance for the development of effective therapeutic biomaterials aimed at repairing damaged or pathological myocardial tissues. Herein, we present evidence that myocardial cells (H9C2) exhibit integrin-based mechanosensing during the initial stage of adhesion (within the first 2 h), enabling them to recognize and respond to variations in substrate stiffnesses. Moreover, the bioinformatics analysis of RNA transcriptome sequencing (RNA-seq) reveals that the gene expressions associated with initial stage focal adhesion (Ctgf, Cyr61, Amotl2, Prickle1, Serpine1, Akap12, Hbegf, and Nedd9) are up-regulated on substrates with elevated Young's modulus. The fluorescent immunostaining results also suggest that increased substrate stiffness enhances the expression of Y397-phosphorylated focal adhesion kinase (FAK Y397), talin, and vinculin and the assembly of F-actin in H9C2 cells, thereby facilitating the adhesion of myocardial cells on the substrate. Next, we utilize fluidic force microscopy (FluidFM)-based single-cell force spectroscopy (SCFS) to quantitatively evaluate the impact of substrate stiffness on the cell adhesion force and adhesion work, thus providing novel insights into the biomechanical regulation of initial cell adhesion. Our findings demonstrate that the maximum adhesion forces of myocardial cells exhibit a rise from 23.6 to 248.0 nN when exposed to substrates with different moduli. It is worth noting that once the αvβ3 integrins are blocked, the disparities in the adhesion forces of myocardial cells on these substrates become negligible. These results exhibit remarkable sensitivity of myocardial cells to mechanical cues of the substrate, highlighting the role of αvβ3 integrin as a biomechanical sensor for the regulation of cell adhesion. Overall, this work offers a prospective approach for the regulation of cell adhesion via integrin mechanosensing with potential practical applications in the areas of tissue engineering and regenerative medicine.

Cellular mechanosignaling for sensing and transducing matrix rigidity

The mechanisms by which cells sense their mechanical environment and transduce the signal through focal adhesions and signaling pathways to the nucleus is an area of key focus for the field of mechanobiology. In the past two years, there has been expansion of our knowledge of commonly studied pathways, such as YAP/TAZ, FAK/Src, RhoA/ROCK, and Piezo1 signaling, as well as the discovery of new interactions, such as the effect of matrix rigidity of cell mitochondrial function and metabolism, which represent a new and exciting direction for the field as a whole. This review covers the most recent advances in the field of substrate stiffness sensing as well as perspective on future directions.

Correlations between serum laminin level and severity of heart failure in patients with chronic heart failure

Objective

This study aimed to investigate the correlation between serum laminin (LN) levels and clinical stages of heart failure in patients with chronic heart failure.

Methods

A total of 277 patients with chronic heart failure were selected from September 2019 to June 2020 in the Department of Cardiology, Second Affiliated Hospital of Nantong University. Based on stages of heart failure, the patients were divided into four groups: stage A, stage B, stage C, and stage D, with 55, 54, 77, and 91 cases, respectively. At the same time, 70 healthy people in this period were selected as the control group. Baseline data were recorded and serum Laminin (LN) levels were measured. The research compared, the differences in baseline data among the four groups of HF and normal controls, and analyzed the correlation between N-terminal pro-brain natriuretic peptide (NT-proBNP) and left ventricular ejection fraction (LVEF). The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of LN in the C-D stage of heart failure. Logistic multivariate ordered analysis was applied to screen the independent related factors of clinical stages of heart failure.

Results

Serum LN levels in patients with chronic heart failure were significantly higher than those in healthy people, which were 33.2 (21.38, 101.9) ng/ml and 20.45 (15.53, 23.04) ng/ml, respectively. With the progression of clinical stages of HF, serum LN and NT-proBNP levels increased, while LVEF gradually decreased (P < 0.05). Correlation analysis showed that LN was positively correlated with NT-proBNP (r = 0.744, P = 0.000) and negatively correlated with LVEF (r = -0.568, P = 0.000). The area under the ROC curve of LN for predicting C and D stages of heart failure was 0.913, 95% confidence interval was 0.882-0.945, P = 0.000, specificity 94.97%, and sensitivity 77.38%. Multivariate Logistic analysis showed that LN, Total bilirubin, NT-proBNP and HA were all independent correlates of heart failure staging.

Conclusion

Serum LN levels in patients with chronic heart failure are significantly increased and are independently correlated with the clinical stages of heart failure. It could potentially be an early warning index of the progression and severity of heart failure.

Design of Functional RGD Peptide-Based Biomaterials for Tissue Engineering

Tissue engineering (TE) is a rapidly expanding field aimed at restoring or replacing damaged tissues. In spite of significant advancements, the implementation of TE technologies requires the development of novel, highly biocompatible three-dimensional tissue structures. In this regard, the use of peptide self-assembly is an effective method for developing various tissue structures and surface functionalities. Specifically, the arginine-glycine-aspartic acid (RGD) family of peptides is known to be the most prominent ligand for extracellular integrin receptors. Due to their specific expression patterns in various human tissues and their tight association with various pathophysiological conditions, RGD peptides are suitable targets for tissue regeneration and treatment as well as organ replacement. Therefore, RGD-based ligands have been widely used in biomedical research. This review article summarizes the progress made in the application of RGD for tissue and organ development. Furthermore, we examine the effect of RGD peptide structure and sequence on the efficacy of TE in clinical and preclinical studies. Additionally, we outline the recent advancement in the use of RGD functionalized biomaterials for the regeneration of various tissues, including corneal repair, artificial neovascularization, and bone TE.