Premna microphylla Turcz pectin-modified diosmetin nanoparticles: A galectin-3 targeting strategy for precise colitis intervention.

70-kDa heat shock protein family is a molecular chaperone that binds to a variety of client proteins and peptides in the cytoplasm. Several studies have revealed binding motifs between 70-kDa heat shock protein family and cytoplasmic proteins by conventional techniques such as phage display library screening. However, little is known about the binding motif based on kinetic parameters determined by surface plasmon resonance analysis. We investigated the major inducible cytosolic 70-kDa heat shock protein (Hsp70)-binding motif with the human leukocyte antigen B*2702-derived peptide Bw4 (RENLRIALRY) by using a Biacore system based on surface plasmon resonance analysis. The K(D) value of Hsp70-Bw4 interaction was 1.8 x 10(-6) m. Analyses with truncated Bw4 variant peptides showed the binding motif of Hsp70 to be seven residues, LRIALRY. To further study the characteristics of this motif, 126 peptides derived from Bw4, each with single amino acid substitution, were synthesized and analyzed for Hsp70 binding affinity. Interestingly, the Hsp70 binding affinity was abrogated when the residues were substituted for by acidic (Asp and Glu) ones at any position. In contrast, if the substitute residue was aromatic (Trp, Tyr, and Phe) or an Arg residue at any position, Hsp70 binding affinity was maintained. Thus, this study presents a new binding motif between Hsp70 and peptides derived from the natural protein human leukocyte antigen B*2702 and may also elucidate some characteristics of the Hsp70 binding characteristic, enhancing our understanding of Hsp70-binding determinants that may influence diverse cellular and physiological processes.

A major hurdle in the treatment of inflammatory bowel disease (IBD) is the lack of effective drug carriers that can precisely deliver the required amount of drug to the sites of inflammation. Available therapies have limited efficacy or severe side effects, largely because of the low concentration of active drugs at the disease sites and non-specific systemic absorption of the administered drugs. Drug delivery targeting the sites of intestinal inflammation offers an approach to maximize therapeutic efficacy while minimizing adverse side effects. We focus on developing formulations that can provide improved local drug administration in the treatment of ulcerative colitis (UC), one of the two main types of IBD. Targeting sites of inflammation in the gastrointestinal tract can be achieved using drug delivery systems that exploit pathophysiological features of the inflamed intestine. Our previous study showed preferential adhesion of a negatively charged small-molecule-based hydrogel to the inflamed colon in murine models of colitis and biopsies from UC patients; further, a corticosteroid drug delivered by this hydrogel demonstrated an improved efficacy compared to the drug alone. Based on our previous experience, we expanded the small-molecule-based hydrogel to polymer-based hydrogels for enhanced selective targeting. We designed the material so that it has a strong affinity towards ulcers. Through molecular structure design, we functionalized thermo-responsive poly(N-isopropylacrylamide) (PNIPAM)-based polymers to modulate the physicochemical properties of the materials and compared the resultant polymers’ gelation and adhesion to the inflamed colon in dextran sulfate sodium (DSS)-induced colitis in mice. We showed that both the types of chemical modification and polymer molecular weight affected the adhesion of the resultant hydrogels to the inflamed colon. We further quantified the disease parameters of colitis for individual mice and correlated the colitis parameters with polymers’ adhesion. Our study suggests a new strategy for targeting the inflamed colon through harnessing charge-mediated interaction and thermo-responsiveness of PNIPAM-based polymers. By adhering to the inflamed mucosa, our delivery system has the potential to maintain the drug locally at the active ulcer sites where it is needed, thereby minimizing the adverse effects of drugs on the healthy tissue. The examination of these polymeric hydrogels’ mucosal binding provides a further understanding of interactions between the polymers and the biological interface in colitis. These studies were performed in preclinical models of UC that develop colitis similar to human UC, as a prerequisite for future studies.

Future Therapeutic Approaches for Inflammatory Bowel Diseases

Osteopontin (OPN) is a cytokine and ligand for multiple members of the integrin family. OPN undergoes the in vivo polymerization catalyzed by cross-linking enzyme transglutaminase 2, which consequently increases the bioactivity through enhanced interaction with integrins. The integrin alpha9beta1, highly expressed on neutrophils, binds to the sequence SVVYGLR only after intact OPN is cleaved by thrombin. The SVVYGLR sequence appears to be cryptic in intact OPN because alpha9beta1 does not recognize intact OPN. Because transglutaminase 2-catalyzed polymers change their physical and chemical properties, we hypothesized that the SVVYGLR site might also be exposed on polymeric OPN. As expected, alpha9beta1 turned into a receptor for polymeric OPN, a result obtained by cell adhesion and migration assays with alpha9-transfected cells and by detection of direct binding of recombinant soluble alpha9beta1 with colorimetry and surface plasmon resonance analysis. Because the N-terminal fragment of thrombin-cleaved OPN, a ligand for alpha9beta1, has been reported to attract neutrophils, we next examined migration of neutrophils to polymeric OPN using time-lapse microscopy. Polymeric OPN showed potent neutrophil chemotactic activity, which was clearly inhibited by anti-alpha9beta1 antibody. Unexpectedly, mutagenesis studies showed that alpha9beta1 bound to polymeric OPN independently of the SVVYGLR sequence, and further, SVVYGLR sequence of polymeric OPN was cryptic because SVVYGLR-specific antibody did not recognize polymeric OPN. These results demonstrate that polymerization of OPN generates a novel alpha9beta1-binding site and that the interaction of this site with the alpha9beta1 integrin is critical to the neutrophil chemotaxis induced by polymeric OPN.

Lactoferrin (LF) is an iron-binding secretory protein, which is distributed in the secondary granules of polynuclear lymphocytes as well as in the milk produced by female mammals. Although it has multiple functions, for example antimicrobial, immunomodulatory, antiviral, and anti-tumor metastasis activities, the receptors responsible for these activities are not fully understood. In this study, the binding epitopes for human LF were first isolated from a hexameric random peptide library displayed on T7 phage. Interestingly, two of the four isolated peptides had a representative cell adhesion motif, Arg-Gly-Asp (RGD), implying that human LF interacts with proteins with the RGD motif. We found that human LF bound to the RGD-containing human extracellular matrix proteins, fibronectin and vitronectin. Furthermore, human LF inhibited cell adhesion to these matrix proteins in a concentration-dependent manner but not to the RGD-independent cell adhesion molecule like laminin or collagen. These results indicate that a function of human LF is to block the various interactions between the cell surface and adhesion molecules. This may explain the multifunctionality of LF.

Bioactive chitosan-BSA Maillard-derived chrysin-loaded nanoparticles: A gastroprotective, biomucoadhesive approach for enhanced oral therapy in ulcerative colitis.

Extracellular RNAs (exRNAs), including in serum, show potential as noninvasive biomarkers. However, their (patho)physiological role is still not fully understood. In this study, we characterized serum exRNAs in patients with inflammatory bowel diseases (IBDs) and evaluated their ability to differentiate ulcerative colitis (UC) from Crohn's disease (CD). We profiled serum exRNAs from 26 IBD patients (15 UC, 11 CD) with active endoscopic disease. Using Small Input Liquid Volume Extracellular RNA-sequencing, we investigated co-expression networks followed by randomized generalized linear modeling. An independent cohort (n = 109 UC, n = 150 CD) was studied to assess the exRNA reflection within the inflamed colonic and ileal mucosa. We detected 41910 exRNAs, capturing 80.9% of genes expressed in intestinal tissue. Network analysis identified 69 clusters, of which one correlated with the distinction between CD and UC (r = -0.70, adjusted P = .006), featuring GNA12 as a hub gene. Serum GNA12 showed no association with fecal calprotectin, disease duration, age, or sex, but did correlate with UC-specific encoding genes (P < .05). Modeling within this upregulated UC-cluster prioritized a signature of 8 exRNAs including GNA12, distinguishing UC from CD with an accuracy [95% CI] of 95.8% [86.7-100.0%]. This elevated 8-marker signature was mirrored in the inflamed UC colon, when compared to the inflamed CD colon and ileum, also when evaluated along the disease location spectrum (P < .05). Liquid biopsies may represent a novel, noninvasive approach in IBD biomarker development. Although larger in-depth studies are needed, this proof-of-concept study bridges noninvasive measurements with established IBD mechanisms, offering a promising tool for accurately distinguishing CD from UC.

Membrane-protein interaction plays key roles in a wide variety of biological processes. Although various methods have been employed to measure membrane binding of soluble proteins, a robust high-throughput assay that is universally applicable to all proteins is lacking at present. Here we report a new fluorescence quenching assay utilizing enhanced green fluorescence protein (EGFP)-fusion proteins and a lipid containing a dark quencher, N-dimethylaminoazobenzenesulfonyl-phosphatidylethanolamine (dabsyl-PE). The EGFP fluorescence emission intensity showed a large decrease (i.e., >50%) when EGFP-fusion proteins bound the vesicles containing 5 mol% dabsyl-PE. This simple assay, which can be performed using either a cuvette-based spectrofluorometer or a fluorescence plate reader, allowed rapid, sensitive, and accurate determination of lipid specificity and affinity for various lipid binding domains, including two pleckstrin homology domains, an epsin N-terminal homology domain, and a phox homology domain. The assay can also be applied to high-throughput screening of small molecules that modulate membrane binding of proteins.

Poster Board III-457 Surface Plasmon Resonance (SPR) Analysis Detects Clinically Significant Low Avidity HPA-1a Antibodies Not Identified by Conventional Serology.

Motherwort synergized with oxytocin for postpartum hemorrhage prevention: Integrated clinical efficacy and mechanism exploration.

The cytoplasmic amino terminus of HCN1, the primary full-length HCN isoform expressed in trout saccular hair cells, was found by yeast two-hybrid protocols to bind the cytoplasmic carboxyl-terminal domain of a protocadherin 15a-like protein. HCN1 was immunolocalized to discrete sites on saccular hair cell stereocilia, consistent with gradated distribution expected for tip link sites of protocadherin 15a. HCN1 message was also detected in cDNA libraries of rat cochlear inner and outer hair cells, and HCN1 protein was immunolocalized to cochlear hair cell stereocilia. As predicted by the trout hair cell model, the amino terminus of rat organ of Corti HCN1 was found by yeast two-hybrid analysis to bind the carboxyl terminus of protocadherin 15 CD3, a tip link protein implicated in mechanosensory transduction. Specific binding between HCN1 and protocadherin 15 CD3 was confirmed with pull-down assays and surface plasmon resonance analysis, both predicting dependence on Ca(2+). In the presence of calcium chelators, binding between HCN1 and protocadherin 15 CD3 was characterized by a K(D) = 2.39 x 10(-7) m. Ca(2+) at 26.5-68.0 microm promoted binding, with K(D) = 5.26 x 10(-8) m (at 61 microm Ca(2+)). Binding by deletion mutants of protocadherin 15 CD3 pointed to amino acids 158-179 (GenBank accession number XP_238200), with homology to the comparable region in trout hair cell protocadherin 15a-like protein, as necessary for binding to HCN1. Amino terminus binding of HCN1 to HCN1, hypothesized to underlie HCN1 channel formation, was also found to be Ca(2+)-dependent, although the binding was skewed toward a lower effective maximum [Ca(2+)] than for the HCN1 interaction with protocadherin 15 CD3. Competition may therefore exist in vivo between the two binding sites for HCN1, with binding of HCN1 to protocadherin 15 CD3 favored between 26.5 and 68 microm Ca(2+). Taken together, the evidence supports a role for HCN1 in mechanosensory transduction of inner ear hair cells.

Background Intestinal fibrosis is a common complication of inflammatory bowel disease (IBD) with limited diagnostic modalities to detect and determine the degree of fibrosis. Fibroblast activation protein alpha (FAP) is a protein with both dipeptidyl peptidase and endopeptidase properties which is virtually absent in healthy tissues and has increased expression in chronic inflammatory and fibrotic diseases. In this study, we investigated the presence of FAP in intestinal fibrosis caused by Crohn’s disease (CD) and ulcerative colitis (UC). Methods For this study, transmural surgical resection specimens were retrieved from the Tytgat institute IBD biobank located at Amsterdam University Medical Center. IBD patients undergoing an ileocecal resection for stricturing CD or a subtotal colectomy for therapy-refractory disease, and patients undergoing a right-sided hemicolectomy or ileocecal resection for dysplasia or non-metastasized colorectal cancer (CRC), were included. All patients had an established diagnosis of (CD, UC, dysplasia or CRC) by previous endoscopy and biopsies and had provided informed consent prior to surgery. FAP protein and gene expression levels were determined using immunohistochemistry staining and quantitative polymerase chain reaction (qPCR). Mass cytometry was used to identify FAP–expressing cells. Results In total, 59 ileal and 35 colonic samples were stained and quantified to asses FAP expression (figure 1). A 1.7-fold and 1.9-fold increase of FAP protein expression was seen in inflamed (mean 22.3, p=0.0069); and stenotic (mean 25.5 p=0.0002) CD ileum compared to healthy non-IBD tissue (mean 13.1). Inflamed UC colon (mean 26.8, p = 0.0406) showed a 1.4-fold increase compared to healthy colon (mean 19.2). For the gene expression, 66 ileal and 42 colonic samples were processed and used for qPCR analysis. A 5-fold and 6.4-fold increase of FAP was found in inflamed (mean 0.011, p=0.0475) and stenotic (mean 0.014, p=0.0042) CD ileum, and a 1.7-fold increase was seen in inflamed UC colon (mean 0.278, p=0.0195) compared to controls (means: ileum 0.002; colon 0.165). Conclusion This is the first study reporting the potential of FAP as a fibrotic biomarker not only in stricturing CD, but also in therapy-refractory UC. Significantly increased FAP protein and gene expression is found in inflamed and stenotic ileum in CD and inflamed colon in UC. Additionally, CD90+GP38+ cells have been identified as the most present FAP expressing cells.

A numerical analysis of the fiber-optic surface plasmon resonance (SPR) sensor with crescent shape of metal coating is presented. The crescent shape of metal coating usually occurs during one side metal deposition on the cylindrical fiber. Here, for analysis of the performance of fiber-optic SPR sensors with such asymmetric metal coating, the method of three-dimensional (3D) ray-tracing and theoretical calculation of electromagnetic reflection and transmission at the metal film are applied simultaneously, which result in 3D analysis with reduced time consumption and data loads. We investigate the characteristic of fiber-optic SPR sensor with asymmetric metal layer, comparing with those of the symmetric metal coated fiber, and discuss the asymmetry effect of the sensors for practical sensing and provide the information for improving sensing capability.

The widespread prevalence of Salmonella underscores the urgent need for rapid, sensitive, and reliable detection methods to ensure food safety and protection of public health. In this study, we successfully developed an integrated detection system that combines immunomagnetic separation with surface plasmon resonance (SPR) analysis. This system achieved high capture efficiencies, exceeding 96.04% in phosphate-buffered saline and over 91.66% in milk samples artificially spiked with S. Typhimurium at concentrations below 4.2 × 104 CFU/mL. However, direct SPR detection of the isolated S. Typhimurium showed limited sensitivity, with a limit of detection (LOD) of 4.2 × 107 CFU/mL. Incorporating a sandwich assay with antibody-conjugated gold nanoparticles significantly enhanced sensitivity, lowering the LOD by six orders of magnitude to 4.2 × 101 CFU/mL. The whole integrated process, integrating immunomagnetic separation with SPR analysis, was completed within 50 min. These results demonstrate that this AuNP-enhanced SPR platform offers both the rapidity and sensitivity essential for effective monitoring of food safety and traceability in Salmonella-related foodborne outbreaks, particularly in products such as milk.

Ceramide kinase (CERK) is a critical mediator of eicosanoid synthesis, and its product, ceramide-1-phosphate (C1P), is required for the production of prostaglandins in response to several inflammatory agonists. In this study, mass spectrometry analysis disclosed that the main forms of C1P in cells were C(16:0) C1P and C(18:0) C1P, suggesting that CERK uses ceramide transported to the trans-Golgi apparatus by ceramide transport protein (CERT). To this end, downregulation of CERT by RNA interference technology dramatically reduced the levels of newly synthesized C1P (kinase-derived) as well as significantly reduced the total mass levels of C1P in cells. Confocal microscopy, subcellular fractionation, and surface plasmon resonance analysis were used to further localize CERK to the trans-Golgi network, placing the generation of C1P in the proper intracellular location for the recruitment of cytosolic phospholipase A(2)alpha. In conclusion, these results demonstrate that CERK localizes to areas of eicosanoid synthesis and uses a ceramide "pool" transported in an active manner via CERT.