Carrier Protein Research Articles

Anti-inflammation Mechanisms of Flavones Are Highly Sensitive to the Position Isomers of Flavonoids: Acacetin vs Biochanin A.

Acacetin (ACA) and biochanin A (BCA) are isomeric monomethoxyflavones with different structural positions of the 4'-methoxy-phenyl group. Both of them are present in many commonly consumed foods, such as citrus fruits and vegetables, and have been discovered with anti-inflammatory activities, but their mechanisms of action are not clearly elucidated at the molecular level. Herein, we reported the structure-activity relationship of ACA and BCA regarding their potency in inhibiting nitric oxide (NO) production, proinflammatory enzyme expression, and mRNA expression of proinflammatory cytokines in the lipopolysaccharide (LPS)-induced RAW 264.7 cells. Furthermore, transcriptome analysis was conducted to map out the overall pathways impacted by these two isomers. Our results showed that ACA possessed higher suppressive activity in nitric oxide (NO) production (IC50 = 23.93 ± 1.74 μM for ACA and IC50 = 71.41 ± 8.07 μM for BCA), inducible nitric oxide synthase (iNOS) expression, and proinflammatory interleukin (IL)-1β mRNA expression, but lower inhibitory activity in IL-6 mRNA expression as compared with BCA. Although two compounds were revealed to bind to c-Src protein according to drug affinity responsive target stability (DARTS) and western blotting results, molecular docking and molecular dynamics (MD) simulation showed that they had different binding sites, which subsequently resulted in different signaling transduction. ACA primarily exerted anti-inflammatory activity through the mitogen-activated protein kinase (MAPK) signaling pathway, the tumor necrosis factor (TNF) signaling pathway, and the hypoxia-inducible factor (HIF)-1 signaling pathway, while BCA was particularly involved in the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway, the nuclear factor kappa B (NF-κB) signaling pathway, the TNF signaling pathway, and the toll-like receptor (TLR) signaling pathway. Moreover, two isomers remained stable in the cell culture medium and did not encounter the biotransformation process in RAW 264.7 cells. However, BCA exhibited insufficient cellular uptake ability and transport efficiency in macrophages compared to ACA. Taken together, ACA is more promising for controlling inflammation and worthy of further study for human use.

Upgrading In Vitro Digestion Protocols with Absorption Models

Intestinal digestion and absorption are complex processes; thus, it is a challenge to imitate them realistically. There are numerous approaches available, with different disadvantages and advantages. The simplest methods to mimic absorption are the non-cell-based transport models but these lack important characteristics of enterocytes of the intestine. Therefore, the most often used method is to measure absorption through viable mammalian cells (most commonly Caco-2 cells, cultured on membrane insert plates), which not only assures the incorporation of brush border enzymes (responsible for the final digestion of peptides and disaccharides), it also simulates the absorption process. This means that influx/efflux transporter-facilitated transport, carrier-mediated transport, endocytosis, and transcytosis is also imitated besides passive diffusion. Still, these also lack the complexity of intestinal epithelium. Organoids or ex vivo models are a better approach if we want to attain precision but the highest accuracy can be achieved with microfluidic systems (gut-on-a-chip models). We propose that more research is necessary, and food absorption should also be studied on gut-on-a-chips, especially with fragmented organoids. Our review supports the choices of a proper intestinal epithelium model, which may have a key role in functional food development, nutrition studies, and toxicity assessment.

Antigenic peptide–thioredoxin fusion chimeras for <i>in vitro</i> stimulus of CD4<sup>+</sup> TCR<sup>+</sup> Jurkat T-cells

Study of CD4+ T-cell response and T-cell receptor (TCR) specificity is crucial for understanding etiology of immune-mediated diseases and developing targeted therapies. However, solubility, accessibility, and stability of synthetic antigenic peptides used in T-cell assays may be a critical point in such studies. Here we present a T-cell activation reporter system using recombinant proteins containing antigenic epitopes fused with bacterial thioredoxin (trx-peptides) and obtained by bacterial expression. We report that co-incubation of CD4+ HA1.7 TCR+ reporter Jurkat 76 TRP-cells with CD80+ HLA-DRB1*01:01+ HeLa-cells or CD4+ Ob.1A12 TCR+ Jurkat 76 TRP with CD80+ HLA-DRB1*15:01+ HeLa-cells resulted in activation of reporter Jurkat 76 TPR after addition of recombinant trx-peptide fusion proteins, containing TCR-specific epitopes. Trx-peptides were comparable with corresponding synthetic peptides in their capacity to activate Jurkat 76 TPR. These data demonstrate that thioredoxin as a carrier protein (trx) for antigenic peptides exhibits minimal interference with recognition of MHC-specific peptides by TCRs and consequent T-cell activation. Our findings highlight potential feasibility of trx-peptides as a reagent for assessing the immunogenicity of antigenic fragments.

Biochemical Pathways Delivering Distinct Glycosphingolipid Patterns in MDA-MB-231 and MCF-7 Breast Cancer Cells.

The complex structure of glycosphingolipids (GSLs) supports their important role in cell function as modulators of growth factor receptors and glutamine transporters in plasma membranes. The aberrant composition of clustered GSLs within signaling platforms, so-called lipid rafts, inevitably leads to tumorigenesis due to disturbed growth factor signal transduction and excessive uptake of glutamine and other molecules needed for increased energy and structural molecule cell supply. GSLs are also involved in plasma membrane processes such as cell adhesion, and their transition converts cells from epithelial to mesenchymal with features required for cell migration and metastasis. Glutamine activates the mechanistic target of rapamycin complex 1 (mTORC1), resulting in nucleotide synthesis and proliferation. In addition, glutamine contributes to the cancer stem cell GD2 ganglioside-positive phenotype in the triple-negative breast cancer cell line MDA-MB-231. Thieno[2,3-b]pyridine derivative possesses higher cytotoxicity against MDA-MB-231 than against MCF-7 cells and induces a shift to aerobic metabolism and a decrease in S(6)nLc4Cer GSL-positive cancer stem cells in the MDA-MB-231 cell line. In this review, we discuss findings in MDA-MB-231, MCF-7, and other breast cancer cell lines concerning their differences in growth factor receptors and recent knowledge of the main biochemical pathways delivering distinct glycosphingolipid patterns during tumorigenesis and therapy.

AP-1 contributes to endosomal targeting of ubiquitin ligase RNF13 via a secondary and novel non-canonical binding motif.

Cellular trafficking between organelles is typically assured by short motifs that contact carrier proteins to transport them to their destination. Ubiquitin E3 ligase RING finger protein 13 (RNF13), a regulator of proliferation, apoptosis, and protein trafficking, localizes to endolysosomal compartments through the binding of a dileucine motif to clathrin adaptor protein complex AP-3. Mutations within this motif reduce the ability of RNF13 to interact with AP-3. Here, our study shows the discovery of a glutamine-based motif that resembles a tyrosine-based motif within RNF13's C-terminal region that binds to the clathrin adaptor protein complex AP-1, notably without a functional interaction with AP-3. Using biochemical, molecular, and cellular approaches in HeLa cells, our study demonstrates that a RNF13 dileucine variant uses an AP-1-dependent pathway to be exported from the Golgi towards the endosomal compartment. Overall, this study provides mechanistic insights into the alternate route used by variant of RNF13's dileucine sorting motif.

Insights into Transient Dimerisation of Carnitine/Acylcarnitine Carrier (SLC25A20) from Sarkosyl/PAGE, Cross-Linking Reagents, and Comparative Modelling Analysis.

The carnitine/acylcarnitine carrier (CAC) is a crucial protein for cellular energy metabolism, facilitating the exchange of acylcarnitines and free carnitine across the mitochondrial membrane, thereby enabling fatty acid β-oxidation and oxidative phosphorylation (OXPHOS). Although CAC has not been crystallised, structural insights are derived from the mitochondrial ADP/ATP carrier (AAC) structures in both cytosolic and matrix conformations. These structures underpin a single binding centre-gated pore mechanism, a common feature among mitochondrial carrier (MC) family members. The functional implications of this mechanism are well-supported, yet the structural organization of the CAC, particularly the formation of dimeric or oligomeric assemblies, remains contentious. Recent investigations employing biochemical techniques on purified and reconstituted CAC, alongside molecular modelling based on crystallographic AAC dimeric structures, suggest that CAC can indeed form dimers. Importantly, this dimerization does not alter the transport mechanism, a phenomenon observed in various other membrane transporters across different protein families. This observation aligns with the ping-pong kinetic model, where the dimeric form potentially facilitates efficient substrate translocation without necessitating mechanistic alterations. The presented findings thus contribute to a deeper understanding of CAC's functional dynamics and its structural parallels with other MC family members.

The multifaceted therapeutical role of low-density lipoprotein receptor family in high-grade glioma.

The diverse roles of the low-density lipoprotein receptor family (LDLR) have been associated with many processes critical to maintaining central nervous system (CNS) health and contributing to neurological diseases or cancer. In this review, we provide a comprehensive understanding of the LDLR's involvement in common brain tumors, specifically high-grade gliomas, emphasizing the receptors' critical role in the pathophysiology and progression of these tumors due to LDLR's high expression. We delve into LDLR's role in regulating cellular uptake and transport through the brain barrier. Additionally, we highlight LDLR's role in activating several signaling pathways related to tumor proliferation, migration, and invasion, engaging readers with an in-depth understanding of the molecular mechanisms at play. By synthesizing current research findings, this review underscores the significance of LDLR during tumorigenesis and explores its potential as a therapeutic target for high-grade gliomas. The collective insights presented here contribute to a deeper appreciation of LDLR's multifaceted roles and implications for physiological and pathological states, opening new avenues for tumor treatment.

In Vitro Screening for ToxCast Chemicals Binding to Thyroxine-Binding Globulin.

Thyroid hormone (TH) carrier proteins play an important role in distributing TH to target tissue as well as maintaining the balance of free versus bound TH in the blood. Interference with the TH carrier proteins has been identified as a potential mechanism of thyroid system disruption. To address the lack of data regarding chemicals binding to these carrier proteins and displacing TH, a fluorescence-based in vitro screening assay was utilized to screen over 1,400 chemicals from the U.S. EPA's ToxCast phase1_v2, phase 2, and e1k libraries for competitive binding to one of the carrier proteins, thyroxine-binding globulin. Initial screening at a single high concentration of 100 μM identified 714 chemicals that decreased signal of the bound fluorescent ligand by 20% or higher. Of these, 297 produced 50% or greater reduction in fluorescence and were further tested in concentration-response (0.004 to 150 μM) to determine relative potency. Ten chemicals were found to have EC50 values <1 μM, 63 < 10 μM, and 141 chemicals between 10 and 100 μM. Utilization of this assay contributes to expanding the number of in vitro assays available for identifying chemicals with the potential to disrupt TH homeostasis. These results support ranking and prioritization of chemicals to be tested in vivo to aid in the development of a framework for predicting in vivo effects from in vitro high-throughput data.

Computational Exploration of Isatin Derivatives for InhA Inhibition in Tuberculosis: Molecular Docking, MD Simulations and ADMET Insights.

Anti-tubercular drug discovery is a critical research area aimed at addressing the global health burden imposed by Mycobacterium tuberculosis. Nowadays, computational techniques have increased the likelihood of drug development compared to traditional, labor-intensive, and time-consuming drug design approaches. The pivotal goal of drug design is to identify compounds capable of selectively targeting protein, thereby disrupting its enzymatic activity. InhA, or NADH-dependent enoyl-acyl carrier protein reductase, stands at the forefront of targeted approaches in the battle against TB. Isatin derivatives have garnered interest for their diverse pharmacological activities. To identify novel isatin derivatives that could serve as potential chemical templates for anti-TB drug discovery by targeting InhA. The present work utilized various computational approaches, including molecular docking, binding free energy calculations, and conformational alignment studies to investigate the binding mode and interactions of carefully selected dataset of 88 isatin derivatives within InhA active site. Study also employed MD simulations of the most promising molecule to check the stability of the protein-ligand complex and in-silico ADMET profiling of the top compounds to predict their pharmacokinetic and toxicity properties. Results provided insights into the structural features contributing to InhA inhibition, assessing overall drug-like characteristics of isatin derivatives and identified compound 48 (BA= -10.4 kcal mol-1 ) with potential for further optimization. MD simulation analysis revealed that compound 48 binds firmly within the InhA protein, exhibiting minimal conformational fluctuations and enhanced stability. Considering the aforementioned, isatin derivatives represents a novel framework for creating targeted InhA inhibitors during anti-TB therapy. However, experimental validations and in-depth analyses are crucial to confirm efficacy and safety of these derivatives as potential InhA inhibitors for TB treatment.

The ABCG2 Transporter Affects Plasma Levels, Tissue Distribution and Milk Secretion of Lumichrome, a Natural Derivative of Riboflavin.

The ABCG2 membrane transporter affects bioavailability and milk secretion of xenobiotics and natural compounds, including vitamins such as riboflavin. We aimed to characterize the in vitro and in vivo interaction of ABCG2 with lumichrome, the main photodegradation product of riboflavin, which has proven in vitro anti-cancer activity and a therapeutical role in antibacterial photodynamic therapy as an efficient photosensitizer. Using MDCK-II polarized cells overexpressing murine Abcg2 and human ABCG2 we found that lumichrome was efficiently transported by both variants. After lumichrome administration to wild-type and Abcg2-/- mice, plasma AUC20-120 min was 1.8-fold higher in Abcg2-/- mice compared with wild-type mice. The liver and testis from Abcg2-/- mice showed significantly higher lumichrome levels compared with wild-type, whereas lumichrome accumulation in small intestine content of wild-type mice was 2.7-fold higher than in Abcg2-/- counterparts. Finally, a 4.1-fold-higher lumichrome accumulation in milk of wild-type versus Abcg2-/- mice was found. Globally, our results show that ABCG2 plays a crucial role in plasma levels, tissue distribution and milk secretion of lumichrome potentially conditioning its biological activity.

Maf expression in B cells restricts reactive plasmablast and germinal center B cell expansion

Precise regulation of B cell differentiation is essential for an effective adaptive immune response. Here, we show that B cell development in mice with B cell-specific Maf deletion is unaffected, but marginal zone B cells, germinal centre B cells, and plasmablasts are significantly more frequent in the spleen of naive Maf-deficient mice compared to wild type controls. In the context of a T cell-dependent immunization, Maf deletion causes increased proliferation of germinal centre B cells and extrafollicular plasmablasts. This is accompanied by higher production of antigen-specific IgG1 antibodies with minimal modification of early memory B cells, but a reduction in plasma cell numbers. Single-cell RNA sequencing shows upregulation of genes associated with DNA replication and cell cycle progression, confirming the role of Maf in cell proliferation. Subsequent pathway analysis reveals that Maf influences cellular metabolism, transporter activity, and mitochondrial proteins, which have been implicated in controlling the germinal centre reaction. In summary, our findings demonstrate that Maf acts intrinsically in B cells as a negative regulator of late B cell differentiation, plasmablast proliferation and germinal centre B cell formation.

Engineered AAV capsid transport mutants overcome transduction deficiencies in the aged CNS

Adeno-associated virus-based gene therapy has enjoyed great successes over the last decade, with FDA approved therapeutics and a robust clinical pipeline. Nonetheless, barriers to successful translation remain. For example, advanced age is associated with impaired brain transduction, with the diminution of infectivity depending on anatomical region and capsid. Given that CNS gene transfer is often associated with neurodegenerative diseases where age is the chief risk-factor, we sought to better understand the causes of this impediment. We assessed two AAV variants hypothesized to overcome factors negatively impacting transduction in the aged brain; specifically, changes in extracellular and cell-surface glycans, and intracellular transport. We evaluated a heparin sulfate proteoglycan null variant with or without mutations enhancing intracellular transport. Vectors were injected into the striatum of young-adult or aged rats to address whether improving extracellular diffusion, removing glycan receptor dependence, or improving intracellular transport are important factors in transducing the aged brain. We found that, regardless of the viral capsid, there was a reduction in many of our metrics of transduction in the aged brain. However, the transport mutant was less sensitive to age, suggesting that changes in the cellular transport of AAV capsids is a key factor in age-related transduction deficiency.

Enhanced Tumor-Targeted Delivery of Arginine-Rich Peptides via a Positive Feedback Loop Orchestrated by Piezo1/integrin β1 Signaling Axis.

Peptide-based drugs hold great potential for cancer treatment, and their effectiveness is driven by mechanisms on how peptides target cancer cells and escape from potential lysosomal entrapment post-endocytosis. Yet, the mechanisms remain elusive, which hinder the design of peptide-based drugs. Here hendeca-arginine peptides (R11) are synthesized for targeted delivery in bladder carcinoma (BC), investigated the targeting efficiency and elucidated the mechanism of peptide-based delivery, with the aim of refining the design and efficacy of peptide-based therapeutics. It is demonstrated that the over-activated Piezo1/integrin β1 (ITGB1) signaling axis significantly facilitates tumor-targeted delivery of R11 peptides via macropinocytosis. Furthermore, R11 peptides formed hydrogen bonds with integrin β1, facilitating targeting and penetration into tumor cells. Additionally, R11 peptides protected integrin β1 from lysosome degradation, promoting its recycling from cytoplasm to membrane. Moreover, this findings establish a positive feedback loop wherein R11 peptides activate Piezo1 by increasing membrane fusion, promoting Ca2+ releasing and resulting in enhanced integrin β1-mediated endocytosis in both orthotopic models and clinical tissues, demonstrating effective tumor-targeted delivery. Eventually, the Piezo1/integrin β1 signaling axis promoted cellular uptake and transport of peptides, establishing a positive feedback loop, promoting mechanical delivery to cancer and offering possibilities for drug modification in cancer therapy.

Revealing the pH-dependent conformational changes in sol g 2.1 protein and potential ligands binding

Sol g 2, a major protein found in the venom of the tropical fire ant (Solenopsis geminata), is well-known for its ability to bind various hydrophobic molecules. In this study, we investigate the binding activity of recombinant Sol g 2.1 protein (rSol g 2.1) with potential molecules, including (E)-β-Farnesene, α-Caryophyllene, and 1-Octen-3-ol at different pH levels (pH 7.4 and 5.5) using fluorescence competitive binding assays (FCBA). Our results revealed that Sol g 2.1 protein has higher affinity binding with these ligands at neutral pH. Relevance to molecular docking and molecular dynamics simulations were utilized to provide insights into the stability and conformational dynamics of Sol g 2.1 and its ligand complexes. After simulation, we found that Sol g 2.1 protein has higher affinity binding with these ligands as well as high structural stability at pH 7.4 than at an acidic pH level, indicating by RMSD, RMSF, Rg, SASA, and principal component analysis (PCA). Additionally, the Sol g 2.1 protein complexes at pH 7.4 showed significantly lower binding free energy (∆Gbind) and higher total residue contributions, particularly from key non-polar amino acids such as Trp36, Met40, Cys62, and Ile104, compared to the lower pH environment. These explain why they exhibited higher binding affinity than the lower pH. Therefore, we suggested that Sol g 2.1 protein is a pH-responsive carrier protein. These findings also expand our understanding of protein–ligand interactions and offer potential avenues for the development of innovative drug delivery strategies targeting Sol g 2.1 protein.

Formation of CdTe core and CdTe@ZnTe core-shell quantum dots via hydrothermal approach using dual capping agents: deciphering the food dye sensing and protein binding applications.

Excessive use of food coloring agents in the food industry to make the food more attractive or improve the taste has caused various health and ecological problems. Therefore, it is necessary to develop a reliable, sensitive, and selective sensing probe to detect food dyes in different food products for future industrial processing and biosafety. In recent decades, surface-functionalized quantum dots (QDs), owing to their unique optical properties, have gained tremendous interest for a wide range of applications, including biomedical, bioimaging and sensing applications. Herein, we have reported the synthesis of excellent colloidal stable and highly luminescent CdTe core and CdTe@ZnTe core-shell QDs using dual functionalizing agents, polyvinyl pyrrolidone and vitamin C. The synthesized QDs were explored as excellent sensing probes for the food dyes carmoisine, Ponceau 4R and tartrazine with limit of detection (LOD) values of 0.097 ± 0.006, 0.147 ± 0.001 and 0.044 ± 0.001 μM for CdTe-PVP QDs and 0.079 ± 0.001, 0.114 ± 0.002 and 0.042 ± 0.001 μM for CdTe@ZnTe-PVP QDs, respectively. The sensitivity of the synthesized QDs for the food dyes was also investigated in real samples (soft drinks and medications). Moreover, considering the potential effects of QDs as therapeutics or nano-drug carriers, the interactions between the synthesized QDs and carrier protein human serum albumin (HSA) were investigated. The binding affinity was observed to be in the order of 104 M-1. QDs were found to quench the intrinsic fluorescence of HSA, and both types of quenching (static and dynamic) occur via electrostatic interactions in association with hydrophobic forces without any significant alteration in the protein structure.

Whole-Genome Resequencing Identifies SNPs in Sucrose Synthase and Sugar Transporter Genes Associated with Sweetness in Coconut.

Coconut (Cocos nucifera L.) is an important agricultural commodity with substantial economic and nutritional value, widely used for various products, including coconut water. The sweetness is an important quality trait of coconut water, which is influenced by genetic and environmental factors. In this study, we utilized next-generation sequencing to identify genetic variations in the coconut genome associated with the sweetness of coconut water. Whole-genome resequencing of 49 coconut accessions, including diverse germplasm and an F2 population of 81 individuals, revealed ~27 M SNPs and ~1.5 M InDels. Sugar content measured by °Bx was highly variable across all accessions tested, with dwarf varieties generally sweeter. A comprehensive analysis of the sugar profiles revealed that sucrose was the major sugar contributing to sweetness. Allele mining of the 148 genes involved in sugar metabolism and transport and genotype-phenotype association tests revealed two significant SNPs in the hexose carrier protein (Cnu01G018720) and sucrose synthase (Cnu09G011120) genes associated with the higher sugar content in both the germplasm and F2 populations. This research provides valuable insights into the genetic basis of coconut sweetness and offers molecular markers for breeding programs aimed at improving coconut water quality. The identified variants can improve the selection process in breeding high-quality sweet coconut varieties and thus support the economic sustainability of coconut cultivation.

With age comes resilience: how mitochondrial modulation drives age-associated fluconazole tolerance in Cryptococcus neoformans.

Infections caused by Cryptococcus neoformans cause more than 180,000 deaths annually. Estimated 1-year mortality for patients receiving care ranges from 20% in developed countries to 70% in developing countries, suggesting that current treatments are inadequate. Some fungal cells can persist and replicate despite the usage of current antifungal regimens, leading to death or treatment failure. Aging in fungi is associated with enhanced tolerance against antifungals and resistance to killing by host cells. This study shows that age-dependent increase in mitochondrial reactive oxygen species drive changes in the regulation of membrane transporters and ergosterol synthesis, ultimately leading to the heightened tolerance against fluconazole in old C. neoformans cells. Understanding the underlying molecular mechanisms of this age-associated antifungal tolerance will enable more targeted antifungal therapies for cryptococcal infections.

Exploring the role of FAT genes in Solanaceae species through genome-wide analysis and genome editing.

Plants produce numerous fatty acid derivatives, and some of these compounds have significant regulatory functions, such as governing effector-induced resistance, systemic resistance, and other defense pathways. This study systematically identified and characterized eight FAT genes (Acyl-acyl carrier protein thioesterases), four in the Solanum lycopersicum and four in the Solanum tuberosum genome. Phylogenetic analysis classified these genes into four distinct groups, exhibiting conserved domain structures across different plant species. Promoter analysis revealed various cis-acting elements, most of which are associated with stress responsiveness and growth and development. Micro-RNA (miRNA) analysis identified specific miRNAs, notably miRNA166, targeting different FAT genes in both species. Utilizing clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated knockout, mutant lines for SlFATB1 and SlFATB3 were successfully generated and exhibited diverse mutation types. Biochemical evaluation of selected mutant lines revealed significant changes in fatty acid composition, with linoleic and linolenic acid content variations. The study also explored the impact of FAT gene knockout on tomato leaf architecture through scanning electron microscopy, providing insights into potential morphological alterations. Knocking out of FAT genes resulted in a significant reduction in both trichome and stoma density. These findings contribute to a comprehensive understanding of FAT genes in Solanaceous species, encompassing genetic, functional, and phenotypic aspects.

Mesenchymal stem cell cryopreservation with cavitation-mediated trehalose treatment

Dimethylsulfoxide (DMSO) has conventionally been used for cell cryopreservation both in research and in clinical applications, but has long-term cytotoxic effects. Trehalose, a natural disaccharide, has been proposed as a non-toxic cryoprotectant. However, the lack of specific cell membrane transporter receptors inhibits transmembrane transport and severely limits its cryoprotective capability. This research presents a method to successfully deliver trehalose into mesenchymal stem cells (MSCs) using ultrasound in the presence of microbubbles. The optimised trehalose concentration was shown to be able to not only preserve membrane integrity and cell viability but also the multipotency of MSCs, which are essential for stem cell therapy. Confocal imaging revealed that rhodamine-labelled trehalose was transported into cells rather than simply attached to the membrane. Additionally, the membranes were successfully preserved in lyophilised cells. This study demonstrates that ultrasonication with microbubbles facilitated trehalose delivery, offering promising cryoprotective capability without the cytotoxicity associated with DMSO-based methods.

Elucidating the Binding Interaction of a Highly Efficient Phytochemical-Sinapic Acid with Human Serum Albumin: A Spectroscopic and Calorimetric Approach

Polyphenolic compounds have received much attention due to their major function as antioxidants. Sinapic acid (SA) is an orally bioavailable phytochemical with excellent free radical scavenging property transported in the blood by human serum albumin (HSA) which is the chief carrier protein found abundantly in human plasma. SA contains a single phenolic group. This study investigates the binding and interaction mechanism between SA and HSA by multiple spectroscopic and calorimetric techniques, such as UV/visible absorption spectroscopy, intrinsic fluorescence studies, Fourier transform infrared (FTIR) spectroscopy and isothermal titration calorimetry (ITC). UV/visible absorption spectroscopy showed hyperchromicity in the absorption spectra, suggestive of structural change due to complex formation between HSA and SA. Intrinsic fluorescence measurements, performed at three different temperatures, showed quenching of the fluorescence spectra and the mechanism of quenching was static in nature which occurred due to ground state complex formation. The FTIR results demonstrated a 16% decrease in α-helical content of the secondary structure of HSA in the presence of SA. Hydrogen bonds and hydrophobic forces were the main forces of interaction, according to the thermodynamic characteristics found through ITC. Moreover, the data obtained through ITC indicated strong binding affinity between HSA and SA and supported the exothermic and spontaneous nature of the interaction.