Conformational Dynamics in Extended RGD-Containing Peptides

Hyperbranched polyamidoamine-RGD peptide/si-circICA1 in the treatment of invasive thyroid cancer through targeting of the miR-486-3p/SERPINA1 axis

Aim: This study aimed to identify molecular markers associated with papillary thyroid cancer (PTC) and investigate the therapeutic potential of targeted nanoscale drugs. Materials & methods: We analyzed the effects of circICA1 and miR-486-3p on B-CPAP cells' proliferation, apoptosis, migration and invasion. The regulation of the miR-486-3p/SERPINA1 axis was explored using quantitative real-time reverse transcription PCR and western blot analyses for metastasis. In vivo, we evaluated the effects of hyperbranched polyamidoamine-RGD peptide/si-circICA1 on PTC growth and metastasis. Results: Enhanced miR-486-3p expression inhibits B-CPAP cells' proliferation and invasion. si-circICA1 delivered via hyperbranched polyamidoamine-RGD peptide nanoparticles shows potential for treating metastasis in PTC. Conclusion: This study identifies key molecular mechanisms underlying PTC invasiveness and suggests a promising therapeutic strategy for PTC using targeted nanoscale drugs.

Design, synthesis and analysis of charged RGD derivatives

In the present study, negatively charged N-Biotin-RGD and positively charged C-Biotin-RGD were designed, synthesized, and characterized with docking analysis. The fixation of MDA-MB-231 cells with formalin made their cell surface neutrally charged thus removing the electrostatic interactions between charged biotinylated RGD derivatives and MDA-MB-231 cells. The results of the binding affinity of biotinylated RGD derivatives against MDA-MB-231 cells showed that N-Biotin-RGD had higher binding affinity than C-Biotin-RGD. The cytotoxic effect was analyzed by incubating charged biotinylated RGD derivatives with live MDA-MB-231 cells. MDA-MB-231 cell surface is negatively charged due to high hypersialyliation of polyglycans and Warburg effect. The results of their cytotoxic activities against live MDA-MB-231 cells were found to be electrostatic in nature. C-Biotin-RGD had an attractive interaction with the MDA-MB-231 cell surface resulting in a higher cytotoxic effect. In comparison, N-Biotin-RGD had a repulsive interaction with the MDA-MB-231 cell surface resulting in a lower cytotoxic effect. Hence, positively charged C-Biotin-RGD is a better cytotoxic agent than a negatively charged N-Biotin-RGD against MDA-MB-231 cells.

Domain-Specific Phase Transitions in a Supramolecular Nanostructure

Understanding thermal phase behavior within nanomaterials can inform their rational design for medical technologies like drug delivery systems and vaccines, as well as for energy technologies and catalysis. This study resolves thermal phases of discrete domains within a supramolecular aramid amphiphile (AA) nanoribbon. Dynamics are characterized by X-band EPR spectroscopy of spin labels positioned at specific sites through the nanoribbon cross-section. The fitting of the electron paramagnetic resonance (EPR) line shapes reveals distinct conformational dynamics, with fastest dynamics at the surface water layer, intermediate dynamics within the flexible cationic head group domain, and slowest dynamics in the interior aramid domain. Measurement of conformational mobility as a function of temperature reveals first- and second-order phase transitions, with melting transitions observed in the surface and head group domains and a temperature-insensitive crystalline phase in the aramid domain. Arrhenius analysis yields activation energies of diffusion at each site. This work demonstrates that distinct thermal phase behaviors between adjacent nanodomains within a supramolecular nanostructure may be resolved and illustrates the utility of EPR spectroscopy for thermal phase characterization of nanostructures.

Sildenafil citrate-loaded targeted nanostructured lipid carrier enhances receptivity potential of endometrial cells via LIF and VEGF upregulation

The main objective of this research is to prepare sildenafil citrate (SC)-loaded arginyl-glycyl-aspartic acid (RGD)-containing nanostructured lipid carrier (SC-loaded NLC-RGD) and evaluate their effects on the receptivity potential of endometrial cells. Hot homogenization method was used to prepare SC-loaded NLC-RGD. Then, size, drug encapsulation, and morphology of prepared nanoparticles were studied by photon correlation spectroscopy technic, ultrafiltration method, and scanning electron microscopy, respectively. Subsequently, the influence of SC-loaded NLC-RGD on endometrial receptivity was evaluated by in vitro implantation assay. Finally, expression of vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), and integrin beta 3 (as endometrial receptivity markers) was assessed in SC-loaded NLC-RGD-treated endometrial cells by reverse transcription polymerase chain reaction (RT-PCR). Particles with a nano-size diameter (92.7 nm), appropriate polydispersity index (0.21), spherical morphology, and acceptable loading efficiency were prepared. In vitro implantation assay showed that SC, SC-loaded NLC, and SC-loaded NLC-RGD improve the rate of endometrial attachment potential by 1.6 ± 0.4, 1.7 ± 0.3, and 2.3 ± 0.3 times, respectively. Analysis of RT-PCR results showed the enhancing mRNA of LIF and VEGF in SC-treated endometrial cells. Results also confirmed the higher influence of SC-loaded NLC-RGD on gene expression patterns in comparison to SC. Using NLC-RGD as a carrier to deliver SC to endometrial cells is an effective approach to improve endometrial receptivity. Upregulation of LIF and VEGF is the probable mechanism by which SC enhances the endometrial receptivity potential.

Dynamics in supramolecular nanomaterials

Self-assembly of amphiphilic small molecules in water leads to nanostructures with customizable structure-property relationships arising from their tunable chemistries. Characterization of these assemblies is generally limited to their static structures -e.g. their geometries and dimensions - but the implementation of tools that provide a deeper understanding of molecular motions has recently emerged. Here, we summarize recent reports showcasing dynamics characterization tools and their application to small molecule assemblies, and we go on to highlight supramolecular systems whose properties are substantially affected by their conformational, exchange, and water dynamics. This review illustrates the importance of considering dynamics in rational amphiphile design.

From the Matrix to the Nucleus and Back: Mechanobiology in the Light of Health, Pathologies, and Regeneration of Oral Periodontal Tissues

Among oral tissues, the periodontium is permanently subjected to mechanical forces resulting from chewing, mastication, or orthodontic appliances. Molecularly, these movements induce a series of subsequent signaling processes, which are embedded in the biological concept of cellular mechanotransduction (MT). Cell and tissue structures, ranging from the extracellular matrix (ECM) to the plasma membrane, the cytosol and the nucleus, are involved in MT. Dysregulation of the diverse, fine-tuned interaction of molecular players responsible for transmitting biophysical environmental information into the cell's inner milieu can lead to and promote serious diseases, such as periodontitis or oral squamous cell carcinoma (OSCC). Therefore, periodontal integrity and regeneration is highly dependent on the proper integration and regulation of mechanobiological signals in the context of cell behavior. Recent experimental findings have increased the understanding of classical cellular mechanosensing mechanisms by both integrating exogenic factors such as bacterial gingipain proteases and newly discovered cell-inherent functions of mechanoresponsive co-transcriptional regulators such as the Yes-associated protein 1 (YAP1) or the nuclear cytoskeleton. Regarding periodontal MT research, this review offers insights into the current trends and open aspects. Concerning oral regenerative medicine or weakening of periodontal tissue diseases, perspectives on future applications of mechanobiological principles are discussed.

A Global Minimization Toolkit for Batch-Fitting and χ2 Cluster Analysis of CW-EPR Spectra

Electron paramagnetic resonance spectroscopy (EPR) is a uniquely powerful technique for characterizing conformational dynamics at specific sites within a broad range of molecular species in water. Computational tools for fitting EPR spectra have enabled dynamics parameters to be determined quantitatively. These tools have dramatically broadened the capabilities of EPR dynamics analysis, however, their implementation can easily lead to overfitting or problems with self-consistency. As a result, dynamics parameters and associated properties become difficult to reliably determine, particularly in the slow-motion regime. Here, we present an EPR analysis strategy and the corresponding computational tool for batch-fitting EPR spectra and cluster analysis of the χ2 landscape in Linux. We call this tool CSCA (Chi-Squared Cluster Analysis). The CSCA tool allows us to determine self-consistent rotational diffusion rates and enables calculations of activation energies of diffusion from Arrhenius plots. We demonstrate CSCA using a model system designed for EPR analysis: a self-assembled nanoribbon with radical electron spin labels positioned at known distances off the surface. We anticipate that the CSCA tool will increase the reproducibility of EPR fitting for the characterization of dynamics in biomolecules and soft matter.