Structure Of Mucins Research Articles

Thirst and the influence of ionic concentration; an investigation into the effect on salivary lubrication and the role of MUC5B

Saliva plays a crucial role in lubricating the oral cavity and maintaining a normal hydrated mouthfeel, with the main macromolecule in saliva, MUC5B, playing a significant role in its lubricating properties. Mucins form a hydrated biogel that covers the oral epithelium and forms part of the mucosal pellicle, maintaining proper hydration. This study investigates the relationship between ionic concentration, saliva lubrication, and the perception of oral dryness. At baseline, sodium was found to be ten times more concentrated in the mucosal pellicle compared to bulk saliva, in contrast to potassium which was only 1.5 times more concentrated in the pellicle. Increasing concentrations of mouthwashes containing sodium or potassium indicated a preferential sequestering of sodium in the mucosal pellicle with sodium chloride rinses being associated with an increased thirst perception. We therefore propose that sodium binds to MUC5B, reducing the electrostatic repulsions between its negatively charged moieties. This interaction subsequently leads to a compaction of the mucin structure, which decreases the hydration of MUC5B and reduces its lubricating properties. We determined that increased sodium concentrations compact the mucin structure as indicated by transmission electron microscopy. However, we found that increased sodium concentrations were associated with improved the lubrication of salivary and MUC5B films in an oral tribology mimic, decreasing the coefficient of friction from 0.044 to 0.018, and 0.416 to 0.100 with the addition of 200 mM sodium chloride for saliva and MUC5B, respectively. MUC5B was also demonstrated to become more hydrated with increasing ionic concentrations, as indicated by Quartz Crystal Microbalance with Dissipation. We therefore propose that increased hydration shells surrounding the sodium counterions are responsible for this improved lubrication via the hydration lubrication mechanism. Lastly, it was observed that the spinnbarkeit of saliva decreased with increasing ionic concentrations, indicating a reduced stretchiness in its rheological properties. However, the concentration of MUC5B alone did not appear to affect spinnbarkeit, highlighting that many factors influence the biophysical properties of saliva.

Effects of theacrine on the astringency of EGCG by affecting salivary protein − EGCG interactions through different molecular mechanisms

(−)-Epigallocatechin gallate (EGCG) and theacrine are involved in imparting tea with its astringent and bitter tastes. This study investigated the effect of theacrine on the astringency of EGCG and its molecular mechanism. Sensory evaluation was used to study the astringent intensities of EGCG solutions in the presence and absence of various concentrations of theacrine. The results indicated a considerable increase in the astringency values of EGCG–theacrine solutions compared with those of EGCG solutions alone. Furthermore, dynamic light scattering (DLS) and molecular dynamics simulations (MD) were to explore the interaction mechanisms. The results revealed that theacrine increased the particle size of EGCG-proline-rich proteins (PRPs) aggregates with that of EGCG and PRPs alone. MD revealed that theacrine potentially acted as a bridge between EGCG and PRPs, promoting their interaction and intensifying the EGCG's astringency. However, theacrine could not bridge two or more mucins owing to the substantial spatial structure of mucin.

Ovarian Causes of Pseudomyxoma Peritonei (PMP)-A Literature Review.

Pseudomyxoma peritonei (PMP) is a rare, progressive, slowly growing, inadequately understood neoplasm with a 5-year progression-free survival rate of as low as 48%. It is characterized by varying degrees of malignancy and the production of mucinous and gelatinous structures. Typically, the development of pseudomyxoma peritonei is associated with the rupture of appendiceal mucinous tumors and other gastrointestinal or ovarian mucinous tumors. The goal of our literature review was to identify various aspects that characterize the ovarian causes of pseudomyxoma peritonei. The authors performed an extensive literature search between 1 February 2024 and 2 March 2024 on the following databases: Pubmed, Scopus, Oxford Journals, and Reaxys, and the findings were summarized into seven main clinical and paraclinical situations. According to our research, the main instances in which pseudomyxoma peritonei can be triggered by an ovarian cause are the following: (1) mucinous cystadenoma; (2) mucinous ovarian cancer; (3) colon cancer with ovarian metastasis; (4) malignant transformation of an ovarian primary mature cystic teratoma; (5) appendiceal mucocele with peritoneal dissemination mimicking an ovarian tumor with peritoneal carcinomatosis; (6) mucinous borderline tumor developing inside an ovarian teratoma; and (7) the association between a mucinous bilateral ovarian cancer and a colonic tumor. In our study, we aimed to provide a comprehensive overview of the ovarian causes of pseudomyxoma peritonei, including its epidemiology, imagery characteristics, symptoms, current treatment, and promising future therapies, in the hopes of finding feasible solutions, as a lack of understanding of this mucus-secreting malignant disease increases the risk of delayed diagnosis or uncontrolled deterioration.

Abstract 2744: Exploring the role of the MSLN/MUC16 interaction in cancer progression via the in situ proximity ligation technique

Abstract Introduction: Mesothelin (MSLN) is a glycoprotein present on the surface of mesothelial cells, sometimes used as a tumor marker. Its overexpression in various cancers, including mesothelioma, ovarian, pancreatic, and lung, is linked to increased tumor aggressiveness, evasion of apoptosis, metastasis, and resistance to treatments. Mucin16 (MUC16) belongs to a family of proteins that play a crucial role in cell adhesion, signaling, and immune responses. In cancer, alterations in mucin expression and structure may contribute to tumor progression and metastasis by enhancing cell survival and immune evasion. Mesothelin is known to interact with mucins, influencing tumor cell behavior and metastatic potential. More specifically, the MSLN/MUC16 interaction facilitates tumor cell invasion and peritoneal spread in ovarian cancer. However, reliable molecular tools to study protein interactions have been scarce. Here, we relied on the Naveni® in situ proximity ligation technology to identify MSLN/MUC16 in various cancer samples. The method detects proteins located within interaction range (<40 nm) by means of antibodies conjugated to oligonucleotides that create amplified fluorescent signal. Since the technique does not compromise the structural integrity of tissues, communication between proteins can be studied in their native environment. Materials & Methods: Human FFPE tissue microarrays (TMA) with ovarian primary carcinoma and matched metastatic cancer (80 cores) and ovarian cancer tissue with normal tissue (100 cores) were deparaffinized and subjected to standard heat-induced antigen retrieval and blocking. Staining against the MSLN/MUC16 interaction was performed with the NaveniFlex Tissue MR Atto647N kit (Navinci Diagnostics). Co-staining antibodies against pan-Cytokeratin and Ki67 were included in the detection mix. Immunofluorescence (IF), using the same MSLN and MUC1 primary antibodies, was completed on an additional slide of each TMA, and then secondary antibodies conjugated to Alexa Fluor™ 488 and 594 were used for detection. Imaging was performed on an Olympus scanner VS200. Results & Discussion: In this study, we showed that the interaction is abundant in ovarian cancer, with a distinguishable difference in the signal presence between cancerous and normal adjacent tissue. Furthermore, the additional tumor marker co-stainings give insights into the tumor invasion and growth. When comparing the Naveni® signal of MSLN/MUC16 against IF staining of each, the Naveni® signal shows true interactions, as opposed to expression patterns. Understanding the roles of mesothelin and mucin in cancer, both individually and in interaction, is crucial for developing targeted therapies and diagnostic tools. Further research on their interaction and specific molecular pathways triggered by it is essential for devising effective strategies to combat cancer progression. Citation Format: Sara Bodbin, Doroteya Raykova, Agata Zieba-Wicher. Exploring the role of the MSLN/MUC16 interaction in cancer progression via the in situ proximity ligation technique [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2744.

Hyper Mucinous Proliferations in the Mucosa of Patients with Inflammatory Bowel Disease: Histological Lesions with a Real Potential for Neoplastic Evolution?

Mucin disfunction is a critical event in the pathogenesis of inflammatory bowel disease (IBD). Although hyper mucinous conditions have a still debated implication in the clinical evolution of this disorder, hyper mucinous villous proliferations were found to have a preneoplastic biologic potential. We studied morphologic and immunophenotypic characteristics of these lesions in ileocolonic resections for IBD to add evidence about the evolutive potential of these lesions in samples with well oriented wall structures. Morphologic characteristics of bowel samples from 20 patients resected for IBD and with raised lesions at gross examination were studied and sections from cases with hyper mucinous lesions were stained with the following antibodies: Ki 67, p21, and p27, which were employed to evaluate the characteristics of the proliferative and differentiative activity of the epithelial structures; mismatch repair proteins and p53 have been studied as proteins implicated in carcinogenesis in IBD-affected mucosa; mucins subtypes in hyper mucinous structures were evaluated with MUC-2 and MUC-6. The results in 11 cases of saplings were that they harbored hyper mucinous proliferations. The occurrence of hyper mucinous structures was not related to dysplastic lesions, pseudo pyloric metaplasia, subtype of disease, or activity. In only one of our cases, mild cytologic atypia in the proliferative compartment was detected. Proliferation markers (Ki 67, p53) were expressed in the proliferative compartments of mucosal crypts and antiproliferative proteins p21 and p27 were expressed in differentiated epithelium. MMR proteins expression was limited to the proliferative compartment of the hyper mucinous projections. Mucin subtypes distribution was regular in the epithelium of hyper mucinous proliferations. The present monocentric retrospective study was conducted on surgical samplings with well oriented crypts. Collected data show that hyper mucinous features are frequent occurrences in raised lesions in IBD patients. In hyper mucinous proliferations of the selected cases, the status of the proliferative cycle, the expression of the proteins most frequently involved in carcinogenetic pathways of mucosa affected by IBD, and the mucins subtypes expression have no evident anomalies. Findings are not consistent with the increased risk of neoplastic evolution observed in other studies; rather, they suggest a hyperplastic nature. However, the capacity of hyper mucinous raised lesions for neoplastic evolution should be ruled out with more extensive prospective studies to identify functional defects that could explain the hypothesized neoplastic potential.

Literature-based Comparative Study between Herbal and Synthetic Mucolytics

Abstract: Coughing and sneezing are the body’s reflexes to various acute and chronic respiratory illnesses like asthma, COPD, lung cancer, etc. : Mucus is a sticky, gelatinous material produced by the mucus gland to protect the airways. Mucolytics, antitussives and expectorants may help in treating hypersecretion of mucin that may lead to cough, cystic fibrosis, asthma, and COPD. Mucolytics if given along with the drugs like corticosteroids, albuterol sulphate, and levalbuterol HCl in asthma and for the management of COPD like corticosteroids and bronchodilators, may help in loosening the viscosity of the mucus and clearing it out. : Mucolytics can be synthetic or herbal in origin and work by one of the three processes, viz. enzymatic degradation, disulphide bond cleavage and calcium chelation. Mucolytics breaks down mucin structure and loosen the mucus, helping it to expel out from the body. Some examples of synthetic mucolytics are Bromhexine and N-acetylcysteine. Herbal mucolytics have traditionally been used for the treatment of cough by indigenous people of India. Malva sylvestris, Zizyphus vulgaris are some of the examples of herbal mucolytics.

Glycoprotein Injectable Hydrogels Promote Accelerated Bone Regeneration through Angiogenesis and Innervation.

Glycoproteins are gaining prominence as multifunctional biomaterials. The study reports development of glycoprotein mucin as biomaterial promoting bone regeneration. Mucin 1 deletion has resulted in stiffer femoral bones with scarce presence of osteoblasts in trabecular linings and its role has been established in determining bone mass and mineralization. Limited information about its structure limits its processability, exploration as biomaterial, which is discussed in this study. The role of mucin in ECM (extracellular cellular matrix) formation validated by RNA sequencing analysis of human bone marrow derived mesenchymal stem cells is reported. The structure and stability of mucins is dependent on the presence of glycans in its structure. A thermosensitive hydrogel acquired from thermosensitive Poly (N-isopropyl acrylamide)-(PNIPAM) modified mucin and collagen is developed. The hydrogel demonstrates porous structure and mechanical strength. Newly formed bone tissue is observed at 8 weeks post-implantation in the hydrogel treated groups. The formation of blood vessels, nerves, and bone is observed with upregulation of angiopoietin (ANG), neurofilament heavy chain (NF-H), and osteoadherin (OSAD) or osteocalcin (OCN) respectively in rat calvarial defects. The outcome demonstrates that the thermosensitive injectable hydrogel accelerates repair and healing in calvarial bone defects making it a promising biodegradable biomaterial capable of regenerating bone by promoting angiogenesis and innervation.

Uncommon Histopathological Variants of a Common Lesion: Mucocele

A mucocele is a salivary gland cyst, which contains mucous material. It usually arises from the minor salivary glands and is broadly of two types: mucus retention cysts and mucus extravasation phenomenon. A wide variety of histological features have been documented in the literature such as myxoglobulosis, mucoceles presenting papillary synovial metaplasia-like changes, superficial mucoceles, and clear cell changes. The present case shows histological features of myxoglobulosis and papillary synovial metaplasia like changes (PSM like changes). This paper reports a case of a 17 years old male patient with a chief complaint of a painless swelling on the lower lip since one and half year. Upon a provisional diagnosis of mucocele, surgical excision was carried out. Histopathological examination revealed a mucus extravasation cyst having lumen filled with unique mucinous globular structures, myxoglobulosis and papillary synovial metaplasia like changes.

Advances in the Applications of Mucin 1 in Cancer Therapy

Mucin 1 belongs to the membrane-binding mucoprotein subfamily, which is normally a highly O-glycosylated polymer protein that is mainly expressed in epithelial cells and some hematopoietic cells. Mucin 1 was overexpressed in many cancer tissues compared to normal tissue with a lower degree of glycosylation. Mucin 1 is weakly O-glycosylated in tumor cells, the core site is exposed, and it is widely distributed on the surface of tumor cells, making it an important tumor marker. Mucin 1 has a wide range of applications in tumor diagnosis, tumor drug targeted delivery, and immunodeficiency therapy. Animal studies and clinical studies suggest that mucin 1 can be used as a target in tumor-targeted therapy. This review covers our current summary of the structure and function of mucin 1, reveals its expression in human tumors, focuses on mucin 1-based targeted therapy regimens, and summarizes the research progress of mucin 1 in targeted tumor therapy.

Keklikte (Alectoris chukar) Özofagus’un Histolojik Yapısı ve Bezlerdeki Müsinlerin Histokimyasal Profili

Mucins secreted by mucus-producing cells are glycoproteins with many important functions such as antimi crobial effect, lubricity and physical barrier. The structure and function of mucins may be different in various tissues. Therefore, we designed our study to reveal the current state of mucin chemistry in the glands located in the partridge's esophagus. The esophagus of total 10 adult partridges, five female and five male, whose carcasses were slaughtered in a private breeding farm were used. The extracted esophageal tissues were fixed in 10% formol-alcohol. Tissues were blocked following routine histologicalprocedures, and histological and histochemical staining techniques were applied to 5 μm thick sections from the blocks. While distinguishing the cervical and thoracic parts of the esophagus, it was observed that the glands were localized in the lamina propria and had the characteristics of simple alveolar glands or simple branched alveolar glands containing two or three secretory units. It was also determined that esophageal glands contain neutral, acidic (COOH and sulfate groups) and N-acetylsialomucins. Thus, it was concluded that the histological structure of the esophagus and the histochemical properties of mucins were relatively similar to other poul- try species.

Principles of glycocalyx engineering with hydrophobic-anchored synthetic mucins.

The cellular glycocalyx is involved in diverse biological phenomena in health and disease. Yet, molecular level studies have been challenged by a lack of tools to precisely manipulate this heterogeneous structure. Engineering of the cell surface using insertion of hydrophobic-terminal materials has emerged as a simple and efficient method with great promise for glycocalyx studies. However, there is a dearth of information about how the structure of the material affects membrane insertion efficiency and resulting density, the residence time of the material, or what types of cells can be utilized. Here, we examine a panel of synthetic mucin structures terminated in highly efficient cholesterylamide membrane anchors for their ability to engineer the glycocalyx of five different cell lines. We examined surface density, residence time and half-life, cytotoxicity, and the ability be passed to daughter cells. We report that this method is robust for a variety of polymeric structures, long-lasting, and well-tolerated by a variety of cell lines.

Tailoring the properties of chitosan by grafting with 2-mercaptobenzoic acid to improve mucoadhesion: in silico studies, synthesis and characterization.

Mucoadhesive polymers improve oral bioavailability of drugs by prolonging the duration of adhesion of drugs with mucosa. Various methods could be employed to address the problems of mucoadhesive polymers like weak adhesion forces. Chemical modification of polymers, such as the addition of a thiol group or thiolation, is another way for improving the polymers' mucoadhesive properties that is studied in present research work. A novel thiomer of chitosan was prepared by attaching 2-mercaptobenzoic acid, a hydrophobic ligand onto it. The docking of thiomer and chitosan with mucin structure showed higher binding energy for former. The prepared thiomer was subjected to X-ray diffraction and DSC which established reduction in crystallinity and formation of a new compound through changes in glass transition, melting point and change in diffraction pattern. The NMR studies established conjugation of 2-mercapto benzoic acid to chitosan. The increased mucoadhesion in thiomer behaviour (2-3fold) was confirmed through mucus glycoprotein assay as well as through texture analysis. The permeation enhancing the property of thiomer was established by demonstrating the permeation of phenol red across thiomer treated intestinal membrane. An in vitro cell toxicity assay was done to establish toxicity of chitosan and thiolated chitosan. Finally, the reduced water uptake of thiomer over chitosan proved that the increase in mucoadhesion is not contributed by swelling. Thus, a thiomer with improved mucoadhesion and enhanced permeation properties was prepared and characterized. Hence, all these properties render the newly synthesized polymer a better alternative to chitosan as an excipient for mucoadhesive drug delivery systems.

Intestinal mucin is a chaperone of multivalent copper

Mucus protects the epithelial cells of the digestive and respiratory tracts from pathogens and other hazards. Progress in determining the molecular mechanisms of mucus barrier function has been limited by the lack of high-resolution structural information on mucins, the giant, secreted, gel-forming glycoproteins that are the major constituents of mucus. Here, we report how mucin structures we determined enabled the discovery of an unanticipated protective role of mucus: managing the toxic transition metal copper. Using two juxtaposed copper binding sites, one for Cu2+ and the other for Cu1+, the intestinal mucin, MUC2, prevents copper toxicity by blocking futile redox cycling and the squandering of dietary antioxidants, while nevertheless permitting uptake of this important trace metal into cells. These findings emphasize the value of molecular structure in advancing mucosal biology, while introducing mucins, produced in massive quantities to guard extensive mucosal surfaces, as extracellular copper chaperones.

Assembly of Poly(ethylene glycol)ylated Oleanolic Acid on a Linear Polymer as a Pseudomucin for Influenza Virus Inhibition and Adsorption

Biomimicry of the mucin barrier function is an efficient strategy to counteract influenza. We report the simple aminolyzation of poly(methyl vinyl ether-alt-maleic anhydride) (PM) using amine-terminated poly(ethylene glycol)ylated oleanolic acid (OAPEG) to mimic the mucin structure and its adsorption of the influenza virus. Direct interactions between influenza hemagglutinin (HA) and the prepared macromolecule evaluated by surface plasmon resonance and isothermal titration calorimetry demonstrated that the multivalent presentation of OAPEG on PM enhanced the binding affinity to HA with a decrease in KD of approximately three orders of magnitude compared with monomeric OAPEG. Moreover, hemagglutination inhibition assay, viral growth inhibition assay, and cytopathic effect reduction assay indicated that the nonglycosylated polymer could mimic natural heavily glycosylated mucin and thus promote the attachment of the virus in a subnanomolar range. Further investigation of the antiviral effects via time-of-addition assay, dynamic light scattering experiments, and transmission electron microscopy photographs indicated that the pseudomucin could adsorb the virion particles and synergistically inhibit the early attachment and final release steps of the influenza infection cycle. These findings demonstrate the effectiveness of the macromolecule in the physical sequestration and prevention of viral infection. Notably, due to its structural similarities with mucin, the biomacropolymer also has the potential for the rational design of antiviral drugs, influenza adsorbents, or filtration materials and the construction of model systems to explore protection against other pathogenic viruses.

Loss of Myosin Vb leads to dysregulation of colonic goblet cell structure and function

BackgroundIntestinal goblet cells secrete a protective mucus layer preventing bacteria and harmful ingested substances from contacting the columnar epithelial cells that line the intestine. Single cell RNAseq data has revealed that goblet cells have high expression of Myosin 5b (Myo5b), a molecular motor that regulates vesicle trafficking in epithelial cells. Myo5b is most widely studied in the small intestine, but it’s role in the colonic epithelium and particularly goblet cells is unknown. A recent study found that Myo5b expression was reduced in inflammatory bowel disease (IBD), a condition that is characterized by dysfunctional mucus; potentially providing a link between Myo5b and goblet cell function. We hypothesized that loss of Myo5b would perturb goblet cell mucus production.MethodsAdult control and intestinal specific tamoxifen inducible VillinCreERT2;Myo5bflox/flox(Myo5b KO) mice were injected intraperitoneally with 2 mg of tamoxifen to deplete intestinal Myo5b. After four days colonic tissue was collected and analyzed.ResultsWe found that loss of Myo5b in vivo results in reduced number of goblet cells in the colon by H&E staining. Muc2 immunostaining and alcian blue staining similarly demonstrated a reduction of mucin within goblet cells. Mucin proteins are heavily o‐glycosylated which makes up 80% of the molecular weight. Normally, mucin structures are terminated by sialic acid which provides a negative charge that protects the mucus protein from bacterial degradation. Staining for sialic acid with the lectin SNA revealed a decrease in sialic acid levels in the mucus of Myo5b KO mice compared to controls. Once sialic acid is removed from mucins, the underlying glycan structures are exposed. Using the lectin WGA to identify the internal glycan oligosaccharide n‐acetyl glucosamine, we observed increased exposure of n‐acetyl glucosamine in Myo5b KO mice compared to control mice; which was consistent with our sialic acid findings. Intestinal goblet cells also secrete wound healing factors including the peptide Trefoil factor 3 (TFF3). Similar to the pattern we observed for Muc2 and sialic acid content, we found decreased levels of TFF3 in the mucosa of Myo5b KO mice.ConclusionsOur data shows that loss of functional Myo5b in the colonic epithelium results in decreased goblet cell numbers and alterations in mucin composition. These data suggest that Myo5b may play an important role in goblet cell mucus production and that mutations affecting Myo5b function may contribute to IBD.

Evaluation of increasing digestible threonine to lysine ratio in corn-soybean meal diets without and with distillers dried grains with solubles on growth performance of growing-finishing pigs.

Corn distillers dried grains with solubles (DDGS) is commonly available and often can lower diet cost for swine diets. This corn co-product is recognized to be a source of dietary insoluble fiber, which can not only increase the villous length of the gut mucosa but also increase intestinal production of mucin. Mucin structure, functions, and synthesis are correlated to Thr intake; consequently, the dietary Thr level may need to be increased when feeding an insoluble fiber source such as corn-DDGS. Thus, the objective of this study was to evaluate if feeding standardized ileal digestible (SID) Thr:Lys ratio at or above the estimated requirement in diets without and with DDGS would influence growth performance in finishing pigs. A total of 2,160 pigs (PIC 337 × 1,050; initially 35.1 ± 0.5 kg) were used in a 112-d growth trial. Pigs were randomly assigned to pens (27 pigs per pen) in a randomized complete block design by body weight (BW) with 20 replications per treatment. Pens of pigs were allotted to one of four dietary treatments that were arranged in a 2 × 2 factorial with main effects of dietary Thr level (normal vs. high) and DDGS (without or with). Treatment diets were formulated in four phases from 34 to 57, 57 to 79, 79 to 104, and 104 to 130 kg BW. Diets with high DDGS were formulated to include 40% DDGS in phases 1 and 2, 30% in phase 3, and 15% in phase 4. The normal Thr diets were formulated to contain 61%, 62%, 63%, and 65% SID Thr:Lys ratios for the four dietary phases, respectively. High Thr diets had SID Thr:Lys ratios of 67%, 68%, 69%, and 72%, respectively. There were no interactions (P > 0.10) observed in any phase or overall between Thr level and added DDGS. For the overall period (day 0 to 112), pigs fed diets without DDGS had increased (P < 0.001) average daily gain (ADG) but reduced (P < 0.001) average daily feed intake (ADFI), leading to increased (P < 0.001) feed efficiency (gain-to-feed ratio [G:F]). There was no evidence for difference (P > 0.10) between pigs fed diets formulated at normal or high SID Thr:Lys ratio. In summary, feeding high levels of DDGS decreased ADG and increased ADFI, which resulted in decreased G:F and lower final BW, regardless of the dietary SID Thr:Lys ratio level. In the current study, increasing the level of digestible Thr in a diet that contained a highly insoluble fiber source did not increase the growth performance of grow-finish pigs.

Structure and Functions of T-cell Immunoglobulin-domain and Mucin- domain Protein 3 in Cancer.

T-cell immunoglobulin (Ig)-domain and mucin-domain (TIM) proteins represent a family of receptors expressed on T-cells that play essential cellular immunity roles. The TIM proteins span across the membrane belonging to type I transmembrane proteins. The N terminus contains an Ig-like V-type domain and a Ser/Thr-rich mucin stalk as a co-inhibitory receptor. The C-terminal tail oriented toward the cytosol predominantly mediates intracellular signaling. This review discusses the structural features and functions of TIM-3, specifically on its role in mediating immune responses in different cell types and the rationale for TIM-3-targeted cancer immunotherapy. TIM-3 has gained significant importance to be a potential biomarker in cancer immunotherapy. It has been shown that blockade with checkpoint inhibitors promotes anti-tumor immunity and inhibits tumor growth in several preclinical tumor models. TIM-3 is an immune regulating molecule expressed on several cell types, including IFNγ-producing T-cells, FoxP3+ Treg cells, and innate immune cells. The roles of TIM-3 in immunosuppression support its merit as a target for cancer immunotherapy.

The Impact of MicroRNAs during Inflammatory Bowel Disease: Effects on the Mucus Layer and Intercellular Junctions for Gut Permeability.

Research on inflammatory bowel disease (IBD) has produced mounting evidence for the modulation of microRNAs (miRNAs) during pathogenesis. MiRNAs are small, non-coding RNAs that interfere with the translation of mRNAs. Their high stability in free circulation at various regions of the body allows researchers to utilise miRNAs as biomarkers and as a focus for potential treatments of IBD. Yet, their distinct regulatory roles at the gut epithelial barrier remain elusive due to the fact that there are several external and cellular factors contributing to gut permeability. This review focuses on how miRNAs may compromise two components of the gut epithelium that together form the initial physical barrier: the mucus layer and the intercellular epithelial junctions. Here, we summarise the impact of miRNAs on goblet cell secretion and mucin structure, along with the proper function of various junctional proteins involved in paracellular transport, cell adhesion and communication. Knowledge of how this elaborate network of cells at the gut epithelial barrier becomes compromised as a result of dysregulated miRNA expression, thereby contributing to the development of IBD, will support the generation of miRNA-associated biomarker panels and therapeutic strategies that detect and ameliorate gut permeability.

RadA, a MSCRAMM Adhesin of the Dominant Symbiote Ruminococcus gnavus E1, Binds Human Immunoglobulins and Intestinal Mucins.

Adhesion to the digestive mucosa is considered a key factor for bacterial persistence within the gut. In this study, we show that Ruminococcus gnavus E1 can express the radA gene, which encodes an adhesin of the MSCRAMMs family, only when it colonizes the gut. The RadA N-terminal region contains an all-β bacterial Ig-like domain known to interact with collagens. We observed that it preferentially binds human immunoglobulins (IgA and IgG) and intestinal mucins. Using deglycosylated substrates, we also showed that the RadA N-terminal region recognizes two different types of motifs, the protein backbone of human IgG and the glycan structure of mucins. Finally, competition assays with lectins and free monosaccharides identified Galactose and N-Acetyl-Galactosamine motifs as specific targets for the binding of RadA to mucins and the surface of human epithelial cells.

Highly sialylated mucin-type glycopeptide from porcine intestinal mucosa after heparin extraction: O-glycan profiling and immunological activity evaluation.

Mucins are the major proteins that distributed on the intestinal mucosa layer and protect the intestine from pathogens infection. The composition of intestinal mucin O-glycans can affect the health of the gastrointestinal tract in pigs. Porcine intestinal mucosa is widely used as the main raw material of heparin extraction. The heparin extraction residues rich in mucins were usually wasted. The structure of mucin derived O-glycans in porcine intestinal mucosa are currently unknown. In this study, we isolated the mucins from the heparin extraction residues and profiled the O-glycans. After heparin extraction, mucin was digested with trypsin, and separated by strong anion exchange chromatography. The mucin derived O-glycans were release by alkaline β elimination, and analyzed by ultra high performance liquid chromatography-porous graphitized carbon-Fourier transform mass spectrometry (UPLC-PGC-FTMS/MS). Thirty five kinds of O-glycans were identified, most of which were Core 3-derived glycans. In particular, the O-glycans containing sialic acid Neu5Ac accounted for 71.93% of the total O-glycans, which were different from that of other species, including mouse intestine, fish intestine, and porcine colon. The high content sialylated mucin may explain its effect in biological processes. Furthermore, the immunological activity results indicated that the porcine intestinal mucin could promote phagocytosis and proliferation without any cytotoxic effects, which may aid in the development of immunomodulators.