[Research progress in the synthesis of 3'- and 6'-sialactose by Escherichia coli].

Human milk oligosaccharides (HMOs) are a structurally complex group of unbound polysaccharides, representing the third-largest solid component in breast milk. They play a crucial role in the intestinal health and immune system development of infants. Sialylated HMOs, including 3'-sialactose (3'-SL) and 6'-sialactose (6'-SL), are major components of HMOs, playing significant roles in immune regulation, anti-inflammatory processes, and promotion of probiotic growth. Currently, the cost-effective production of high-value sialactose by microbial fermentation with readily available raw materials has become a research hotspot due to the high nutritional value and potential applications of sialylated HMOs in infant food. This paper summarizes the functions and biosynthesis of 3'-SL and 6'-SL. Furthermore, it reviews the research progress in the synthesis of sialactose by Escherichia coli, offering valuable insights for future industrial production.

6'-Sialyllactose Alleviates Muscle Fatigue through Reduced Blood Lactate Level after Treadmill Exercise in Mice.

6'-Sialyllactose (6'-SL), found in human breast milk, exhibits anti-inflammatory, immune function-enhancing, brain development-promoting, and gut health-improving effects. However, its effects on muscle fatigue remain unknown. Here, we aimed to investigate the effects of 6'-SL on blood lactate level, muscle fiber type, and oxidative phosphorylation protein complexes (OXPHOS) in muscle after exercise using C57BL/6J male mice. C57BL/6J mice were randomly assigned to control or 100 mg/kg 6'-SL. After 12 weeks of 6'-SL administration, the mice were made to perform treadmill exercise; their blood lactate and glucose levels were measured at the basal level (rest) and 0, 5, and 10 min after treadmill exercise. Results showed that 6'-SL treatment in C57BL/6J mice significantly reduced blood lactate level and improved blood glucose level. Moreover, 6'-SL increased the expression of slow-myosin heavy chain (MHC) and OXPHOS in gastrocnemius muscle. In addition, 6'-SL treatment for 12 weeks did not affect food intake, serum biomarkers of tissue injury, and lipid profiles compared with those of the controls. These findings indicate that non-toxic 6'-SL suppressed muscle fatigue during exercise by promoting protein expression of muscle fibers, especially slow-twitch muscle fibers characterized by abundant OXPHOS complexes and decreased blood lactate level. This study suggests that 6'-SL holds promise as a nutritional supplement in exercise and clinical settings, subject to further validation.

Rational modification of Neisseria meningitidis ß1,3-N-acetylglucosaminyltransferase for lacto-N-neotetraose synthesis with reduced long-chain derivatives.

Lacto-N-neotetraose (LNnT), as a neutral core structure within human milk oligosaccharides (HMOs), has garnered widespread attention due to its exceptional physiological functions. In the process of LNnT synthesis using cellular factory approaches, substrate promiscuity of glycosyltransferases leads to the production of longer oligosaccharide derivatives. Here, rational modification of ß1,3-N-acetylglucosaminyltransferase from Neisseria meningitidis (LgtA) effectively decreased the concentration of long-chain LNnT derivatives. Specifically, the optimal ß1,4-galactosyltransferase (ß1,4-GalT) was selected from seven known candidates, enabling the efficient synthesis of LNnT in Escherichia coli BL21(DE3). Furthermore, the influence of lactose concentration on the distribution patterns of LNnT and its longer derivatives was investigated. The modification of LgtA was conducted with computational assistance, involving alanine scanning based on molecular docking to identify the substrate binding pocket and implementing large steric hindrance on crucial amino acids to obstruct LNnT entry. The implementation of saturation mutagenesis at positions 223 and 228 of LgtA yielded advantageous mutant variants that did not affect LNnT synthesis while significantly reducing the production of longer oligosaccharide derivatives. The most effective mutant, N223I, reduced the molar ratio of long derivatives by nearly 70 %, showcasing promising prospects for LNnT production with diminished byproducts.

Human milk oligosaccharides are associated with maternal genetics and respiratory health of human milk-fed children.

Breastfeeding provides many health benefits, but its impact on respiratory health remains unclear. This study addresses the complex and dynamic nature of the mother-milk-infant triad by investigating maternal genomic factors regulating human milk oligosaccharides (HMOs), and their associations with respiratory health among human milk-fed infants. Nineteen HMOs are quantified from 980 mothers of the CHILD Cohort Study. Genome-wide association studies identify HMO-associated loci on chromosome 19p13.3 and 19q13.33 (lowest P = 2.4e-118), spanning several fucosyltransferase (FUT) genes. We identify novel associations on chromosome 3q27.3 for 6'-sialyllactose (P = 2.2e-9) in the sialyltransferase (ST6GAL1) gene. These, plus additional associations on chromosomes 7q21.32, 7q31.32 and 13q33.3, are replicated in the independent INSPIRE Cohort. Moreover, gene-environment interaction analyses suggest that fucosylated HMOs may modulate overall risk of recurrent wheeze among preschoolers with variable genetic risk scores (P < 0.01). Thus, we report novel genetic factors associated with HMOs, some of which may protect the respiratory health of children.

Dietary human milk oligosaccharides reduce allergic airway inflammation by modulating SCFAs level and ILC2 activity.

Group 2 innate lymphoid cells (ILC2s) play a crucial role in the progression of asthma, yet the regulatory mechanisms modulating ILC2 responses in asthma remain underexplored. Human milk oligosaccharides (HMOs), vital non-nutritive components of breast milk, are known to significantly shape immune system development and influence the incidence of allergic diseases. However, their impact on ILC2-driven asthma is not fully understood. Our research reveals that dietary HMOs act as potent inhibitors of ILC2 responses and allergic airway inflammation. Treatment with 2'-fucosyllactose (2'-FL) and 6'-sialyllactose (6'-SL) significantly reduced ILC2-related airway inflammation induced by papain or Alternaria alternata in mice, evidenced by decreased eosinophil (EOS) infiltration and lower IL-5 and IL-13 levels in BALF. Notably, while ILC2 expresses HMO receptors, HMO did not act directly on ILC2 but potentially modulated their activity through alterations in gut microbiota derived SCFAs. HMO treatments alleviated airway inflammation in SCFA-dependent manners, with SCFA depletion or receptor blocking reversing these beneficial effects. This study reveals the potential of dietary HMOs in managing asthma through modulation of ILC2 activity and the gut-lung axis, proposing a new therapeutic avenue that utilises the immunomodulatory capacities of nutritional components to combat respiratory diseases.

6'-Sialyllactose Enhances Exercise Performance via Increased Muscle Mass and Strength.

Sialyllactose (SL) is a functional human milk oligosaccharide essential for immune support, brain development, intestinal maturation, and antiviral defense. However, despite its established health benefits, the effect of SL on exercise performance and muscle mass in mice remains unknown. Here, we aimed to investigate, for the first time, the effects of 6'-SL on muscle functions. Seven-week-old male C57BL/6J mice were administered 100 mg/kg 6'-SL for 12 weeks, after which exhaustive treadmill performance was conducted. Moreover, muscle strength was examined by grip strength, and muscle phenotype characteristics such as muscle mass, muscle fiber size, and muscle protein expression were also examined. The administration of 6'-SL significantly improved exhaustive treadmill performance metrics, including distance and exhaustion time. Grip strength was also increased by 6'-SL administration. Additionally, 6'-SL increased muscle mass in both the gastrocnemius (GAS) and soleus. 6'-SL administration led to an increase in the minimum Feret's diameter and the protein expression of total myosin heavy chain in the GAS muscle. In conclusion, 6'-SL administration in vivo led to increased running distance and time by increasing muscle mass and strength. These findings collectively indicate that 6'-SL is a potential agent for improving muscle health and exercise performance.

Glycopolymer with Sulfated Fucose and 6'-Sialyllactose as a Dual-Targeted Inhibitor on Resistant Influenza A Virus Strains.

The frequent mutations of influenza A virus (IAV) have led to an urgent need for the development of innovative antiviral drugs. Glycopolymers offer significant advantages in biomedical applications owing to their biocompatibility and structural diversity. However, the primary challenge lies in the design and synthesis of well-defined glycopolymers to precisely control their biological functionalities. In this study, functional glycopolymers with sulfated fucose and 6'-sialyllactose were successfully synthesized through ring-opening metathesis polymerization and a postmodification strategy. The optimized heteropolymer exhibited simultaneous targeting of hemagglutinin and neuraminidase on the surface of IAV, as evidenced by MU-NANA assay and hemagglutination inhibition data. Antiviral experiments demonstrated that the glycopolymer displayed broad and efficient inhibitory activity against wild-type and mutant strains of H1N1 and H3N2 subtypes in vitro, thereby establishing its potential as a dual-targeted inhibitor for combating IAV resistance.

Development and Validation of Novel Z-360-Based Macromolecules for the Active Targeting of CCK2-R.

The cholecystokinin type 2 receptor (CCK2-R) represents an ideal target for cancer therapy since it is overexpressed in several tumors and is associated with poor prognosis. Nastorazepide (Z-360), a selective CCK2-R antagonist, has been widely investigated as a CCK2-R ligand for targeted therapy; however, its high hydrophobicity may represent a limit to cell selectivity and optimal in vivo biodistribution. Here, we present three new fluorescent Z-360 derivatives (IP-002G-Rho, IP-002L-Rho, and IP-002M-Rho) in which nastorazepide was linked, through spacers bearing different saccharides (glucose (G), lactose (L), and maltotriose (M)), to sulforhodamine B. A fourth compound (IP-002H-Rho) with no pendant sugar was also synthesized as a control. Through two-dimensional (2D) and three-dimensional (3D) in vitro studies, we evaluated the compound association with and selectivity for CCK2-R-overexpressing cells (A431-CCK2-R+) vs CCK2-R-underexpressing cells (A431 WT). 2D in vitro studies highlighted a progressive increase of IP-002x-Rho association with A431-CCK2-R+ cells according to the linker hydrophilicity, that is, maltotriose > lactose > glucose > hydrogen, with IP-002M-Rho showing a 2.4- and a 1.36-fold higher uptake than IP-002G-Rho and IP-002L-Rho, respectively. Unexpectedly, IP-002H-Rho showed a similar cell association to that of IP-002L-Rho but with no difference between the two tested cell lines. On the contrary, association with A431-CCK2-R+ cells as compared to the A431 WT was found to be 1.08-, 1.14-, and 1.37-fold higher for IP-002G-Rho, IP-002L-Rho, and IP-002M-Rho, respectively, proving IP-002M-Rho to be the best-performing compound, as also confirmed by competition studies. Trafficking studies on A431-CCK2-R+ cells incubated with IP-002M-Rho suggested the coexistence of receptor-mediated endocytosis and simple diffusion. On the contrary, a high and selective uptake of IP-002M-Rho by A431-CCK2-R+ cells only was observed on 3D scaffolds embedded with cells, underlining the importance of 3D models in in vitro preliminary evaluation.

Co-immobilization of a bi-enzymatic cascade into hierarchically porous MIL-53 for efficient 6'-sialyllactose production.

6'-Sialyllactose (6'-SL), the most abundant sialylated human milk oligosaccharide, has attracted attention for its potential application in supplementary infant formulas. Herein, we report a facile strategy to construct a cascade bioreactor for the enzymatic synthesis of 6'-SL by co-immobilizing an enzymatic module consisting of CMP-sialic acid synthase and α-2,6-sialyltransferase into hierarchically porous MIL-53 (HP-MIL-53). The as-prepared HP-MIL-53 showed high enzyme immobilization capacity, reaching 226 mg g-1. Furthermore, the co-immobilized enzymes exhibited higher initial catalytic efficiency, and thermal, pH and storage stability than the free ones. Finally, the 6'-SL yield remained >80% after 13 cycles of use. We expect that HP-MIL-53 would have potential industrial applications in the enzymatic modular synthesis of 6'-SL and other glycans.

Sialyllactose supplementation enhances sialylation of Fc-fusion glycoprotein in recombinant Chinese hamster ovary cell culture.

Sialylation during N-glycosylation plays an important role in the half-life of therapeutic glycoproteins in vivo and has sparked interest in the production of therapeutic proteins using recombinant Chinese hamster ovary (rCHO) cells. To improve the sialylation of therapeutic proteins, we examined the effect of sialyllactose supplementation on sialylation of Fc-fusion glycoproteins produced in rCHO cells. Two enzymatically-synthesized sialyllactoses, 3'-sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL), were administered separately to two rCHO cell lines producing the same Fc-fusion glycoprotein derived from DUKX-B11 and DG44, respectively. Two sialyllactoses successfully increased sialylation of Fc-fusion glycoprotein in both cell lines, as evidenced by isoform distribution, sialylated N-glycan formation, and sialic acid content. Increased sialylation by adding sialyllactose was likely the result of increased amount of intracellular CMP-sialic acid (CMP-SA), the direct nucleotide sugar for sialylation. Furthermore, the degree of sialylation enhanced by sialyllactoses was slightly effective or nearly similar compared with the addition of N-acetylmannosamine (ManNAc), a representative nucleotide sugar precursor, to increase sialylation of glycoproteins. The effectiveness of sialyllactose was also confirmed using three commercially available CHO cell culture media. Taken together, these results suggest that enzymatically-synthesized sialyllactose represents a promising candidate for culture media supplementation to increase sialylation of glycoproteins in rCHO cell culture.

Sialyllactose preserves residual hearing after cochlear implantation.

In individuals with hearing loss, protection of residual hearing is essential following cochlear implantation to facilitate acoustic and electric hearing. Hearing preservation requires slow insertion, atraumatic electrode and delivery of the optimal quantity of a pharmacological agent. Several studies have reported variable hearing outcomes with osmotic pump-mediated steroid delivery. New drugs, such as sialyllactose (SL) which have anti-inflammatory effect in many body parts, can prevent tissue overgrowth. In the present study, the positive effects of the pharmacological agent SL against insults were evaluated in vitro using HEI-OC1 cells. An animal model to simulate the damage due to electrode insertion during cochlear implantation was used. SL was delivered using osmotic pumps to prevent loss of the residual hearing in this animal model. Hearing deterioration, tissue fibrosis and ossification were confirmed in this animal model. Increased gene expressions of inflammatory cytokines were identified in the cochleae following dummy electrode insertion. Following the administration of SL, insertion led to a decrease in hearing threshold shifts, tissue reactions, and inflammatory markers. These results emphasize the possible role of SL in hearing preservation and improve our understanding of the mechanism underlying hearing loss after cochlear implantation.

LacdiNAc synthase B4GALNT3 has a unique PA14 domain and suppresses N-glycan capping.

Structural variation of N-glycans is essential for the regulation of glycoprotein functions. GalNAcß1-4GlcNAc (LacdiNAc or LDN), a unique subterminal glycan structure synthesized by B4GALNT3 or B4GALNT4, is involved in the clearance of N-glycoproteins from the blood and maintenance of cell stemness. Such regulation of glycoprotein functions by LDN is largely different from that by the dominant subterminal structure, N-acetyllactosamine (Galß1-4GlcNAc, LacNAc). However, the mechanisms by which B4GALNT activity is regulated and how LDN plays different roles from LacNAc remain unclear. Here, we found that B4GALNT3 and four have unique domain organization containing a noncatalytic PA14 domain, which is a putative glycan-binding module. A mutant lacking this domain dramatically decreases the activity toward various substrates, such as N-glycan, O-GalNAc glycan, and glycoproteins, indicating that this domain is essential for enzyme activity and forms part of the catalytic region. In addition, to clarify the mechanism underlying the functional differences between LDN and LacNAc, we examined the effects of LDN on the maturation of N-glycans, focusing on the related glycosyltransferases upstream and downstream of B4GALNT. We revealed that, unlike LacNAc synthesis, prior formation of bisecting GlcNAc in N-glycan almost completely inhibits LDN synthesis by B4GALNT3. Moreover, the presence of LDN negatively impacted the actions of many glycosyltransferases for terminal modifications, including sialylation, fucosylation, and human natural killer-1 synthesis. These findings demonstrate that LDN has significant impacts on N-glycan maturation in a completely different way from LacNAc, which could contribute to obtaining a comprehensive overview of the system regulating complex N-glycan biosynthesis.

Rational Design of Highly Selective Sialyllactose-Imprinted Nanogels.

We describe a facile method to prepare water-compatible molecularly imprinted polymer nanogels (MIP NGs) as synthetic antibodies against target glycans. Three different phenylboronic acid (PBA) derivatives were explored as monomers for the synthesis of MIP NGs targeting either α2,6- or α2,3-sialyllactose, taken as oversimplified models of cancer-related sT and sTn antigens. Starting from commercially available 3-acrylamidophenylboronic acid, also its 2-substituted isomer and the 5-acrylamido-2-hydroxymethyl cyclic PBA monoester derivative were initially evaluated by NMR studies. Then, a small library of MIP NGs imprinted with the α2,6-linked template was synthesized and tested by mobility shift Affinity Capillary Electrophoresis (msACE), to rapidly assess an affinity ranking. Finally, the best monomer 2-acrylamido PBA was selected for the synthesis of polymers targeting both sialyllactoses. The resulting MIP NGs display an affinity constant≈106 M-1 and selectivity towards imprinted glycans. This general procedure could be applied to any non-modified carbohydrate template possessing a reducing end.

Galectin-receptor interaction: a key player in liver fibrosis induced by Schistosoma japonicum infection.

BACKGROUND: Schistosoma japonicum eggs lodge in the liver and induce a fibrotic granulomatous immune response in the liver of host. Galectin 3 (Gal-3) is a protein implicated in fibrosis in multiple organs. However, the pathology and molecular mechanisms promoting hepatic granuloma formation remain poorly understood. METHODS: To investigate the effect of blocking galectin-receptor interactions by α-lactose on liver immunopathology in mice with S. japonicum infection, C57BL/6 mice were infected with S. japonicum and alpha (α)-lactose was intraperitoneally injected to block the interactions of galectins and their receptors. RESULTS: Compared with S. japonicum-infected mice, there were significantly decreased Gal-3 mRNA and protein expression levels, decreased intensity of Gal-3 fluorescence in the liver, decreased serum ALT and AST levels, decreased egg numbers of S. japonicum in the liver section, attenuated hepatic and spleen pathology, and alleviated liver fibrosis accompanied with decreased protein expression levels of fibrosis markers [α-smooth muscle actin (α-SMA), collagen I, and collagen IV] in the liver of S. japonicum-infected mice blocked galectin-receptor interactions with hematoxylin-eosin staining, Masson's trichrome staining, immunohistochemistry, or Western blot analysis. Compared with S. japonicum-infected mice, blocking galectin-receptor interactions led to increased eosinophil infiltration and higher eosinophil cationic protein (ECP) expression in the liver, accompanied by increased mRNA levels of eosinophil granule proteins [ECP and eosinophil peroxidase (EPO)], IL-5, CCL11, and CCR3 in the liver and decreased mRNA levels of Gal-3 and M2 macrophage cytokines (TGF-ß, IL-10, and IL-4) in the liver and spleen by using quantitative real-time reverse transcription-polymerase chain reaction. In addition, there were increased Beclin1 protein expression and protein expression ratio of LC3B-II/LC3B-I and decreased p62 protein expression and protein expression ratios of phospho-mTOR/mTOR and phospho-AKT/AKT by Western blot; increased double-labeled F4/80+/LC3B+ cells by immunofluorescence staining; increased M1 macrophage polarization in the liver of S. japonicum-infected mice blocked galectin-receptor interactions by flow cytometric analysis and immunofluorescence staining. CONCLUSIONS: Our data found that blockage of galectin-receptor interactions downregulated Gal-3, which in turn led to reduced liver functional damage, elevated liver eosinophil recruitment, promoted macrophage autophagy through the Akt/mTOR signaling pathway, and alleviated liver pathology and fibrosis. Therefore, Gal-3 plays a pivotal role during S. japonicum infection and could be a target of pharmacologic potential for liver fibrosis induced by S. japonicum infection.

Synthesis and unexpected binding of monofluorinated N,N'-diacetylchitobiose and LacdiNAc to wheat germ agglutinin.

Fluorination of carbohydrate ligands of lectins is a useful approach to examine their binding profile, improve their metabolic stability and lipophilicity, and convert them into 19F NMR-active probes. However, monofluorination of monovalent carbohydrate ligands often leads to a decreased or completely lost affinity. By chemical glycosylation, we synthesized the full series of methyl ß-glycosides of N,N'-diacetylchitobiose (GlcNAcß(1-4)GlcNAcß1-OMe) and LacdiNAc (GalNAcß(1-4)GlcNAcß1-OMe) systematically monofluorinated at all hydroxyl positions. A competitive enzyme-linked lectin assay revealed that the fluorination at the 6'-position of chitobioside resulted in an unprecedented increase in affinity to wheat germ agglutinin (WGA) by one order of magnitude. For the first time, we have characterized the binding profile of a previously underexplored WGA ligand LacdiNAc. Surprisingly, 4'-fluoro-LacdiNAc bound WGA even stronger than unmodified LacdiNAc. These observations were interpreted using molecular dynamic calculations along with STD and transferred NOESY NMR techniques, which gave evidence for the strengthening of CH/π interactions after deoxyfluorination of the side chain of the non-reducing GlcNAc. These results highlight the potential of fluorinated glycomimetics as high-affinity ligands of lectins and 19F NMR-active probes.

Potential biological functions and future perspectives of sialylated milk oligosaccharides.

Sialyllactoses (SLs) primarily include sialylated human milk oligosaccharides (HMOs) and bovine milk oligosaccharides (BMOs). First, the safety assessment of 3'-sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL) revealed low toxicity in various animal models and human participants. SLs constitute a unique milk component, highlighting the essential nutrients and bioactive components crucial for infant development, along with numerous associated health benefits for various diseases. This review explores the safety, biosynthesis, and potential biological effects of SLs, with a specific focus on their influence across various physiological systems, including the gastrointestinal system, immune disorders, rare genetic disorders (such as GNE myopathy), cancers, neurological disorders, cardiovascular diseases, diverse cancers, and viral infections, thus indicating their therapeutic potential.

Ameliorating effect of 2'-fucosyllactose and 6'-sialyllactose on lipopolysaccharide-induced intestinal inflammation.

Human milk oligosaccharides (HMO) affect gut microbiota during neonatal development, particularly with respect to the immune system. Bovine milk-based infant formulas have low oligosaccharide contents. Thus, efforts to fortify infant formulas with HMO are being undertaken. Two major HMO, 2'-fucosyllactose (2'-FL) and 6'-sialyllactose (6'-SL), exert anti-inflammatory effects; however, the associations between anti-inflammatory effects induced by 2'-FL and 6'-SL cotreatment and gut microbiota composition and metabolite modulation remain unclear. Therefore, in this study, we evaluated the effects of a mixture of these HMO. To determine the optimal HMO ratio for anti-inflammatory effects and elucidate its mode of action, LPS-induced inflammatory HT-29 epithelial cells and intestinal-inflamed suckling mice were treated with various mixtures of 2'-FL and 6'-SL. A 2'-FL:6'-SL ratio of 5:1 was identified as the most effective pretreatment HMO mixture in vitro; thus, this ratio was selected and used for low-, middle-, and high-dose treatments for subsequent in vivo studies. In vivo, high-dose HMO treatment restored LPS-induced inflammation symptoms, such as BW loss, colon length reduction, histological structural damage, and intestinal gene expression related to inflammatory responses. High-dose HMO was the only treatment that modulated the major phyla Bacteroidetes and Firmicutes and the genera Ihubacter, Mageeibacillus, and Saccharofermentans. These changes in microbial composition were correlated with intestinal inflammation-related gene expression and short-chain fatty acid production. To our knowledge, our study is the first to report the effects of Ihubacter, Mageeibacillus, and Saccharofermentans on short-chain fatty acid levels, which can subsequently affect inflammatory cytokine and tight junction protein levels. Conclusively, the HMO mixture exerted anti-inflammatory effects through changes in microbiota and metabolite production. These findings suggest that supplementation of infant formula with HMO may benefit formula-fed infants by forming unique microbiota contributing to neonatal development.

A FRET based ultrasensitive fluorescent aptasensor for 6'-sialyllactose detection.

As a kind of human milk oligosaccharide, 6'-sialyllactose (6'-SL) plays an important role in promoting infant brain development and improving infant immunity. The content of 6'-SL in infant formula milk powder is thus one of the important nutritional indexes. Since the lacking of efficient and rapid detection methods for 6'-SL, it is of great significance to develop specific recognition elements and establish fast and sensitive detection methods for 6'-SL. Herein, using 6'-SL specific aptamer as the recognition element, catalytic hairpin assembly as the signal amplification technology and quantum dots as the signal label, a fluorescence biosensor based on fluorescence resonance energy transfer (FRET) was constructed for ultra-sensitive detection of 6'-SL. The detection limit of this FRET-based fluorescent biosensor is 0.3 nM, and it has some outstanding characteristics such as high signal-to-noise ratio, low time-consuming, simplicity and high efficiency in the actual sample detection. Therefore, it has broad application prospect in 6'-SL detection.

Conocimientos sobre COVID-19 en población general adulta tras dos años de pandemia.

OBJETIVO: identificar el nivel de conocimientos sobre la COVID-19 que tiene la población adulta residente en Gijón (España) después de dos años de pandemia. MÉTODOS: se realizó un estudio descriptivo transversal entre marzo del 2021 y marzo del 2022. Los datos se obtuvieron mediante un cuestionario telefónico sobre una muestra estratificada de tres zonas básicas de salud de Gijón, España (Calzada, Zarracina y Parque-Somió). El tamaño muestral se compuso de 305 personas. Se empleó el análisis ji-cuadrado para estudiar la relación entre variables categóricas y ANOVA para comparar las medias de la puntuación total por zona básica. Se realizaron regresiones logísticas para calcular las odds ratio entre la variable dependiente (poseer conocimientos avanzados) y las independientes (variables sociodemográficas). Se construyó un modelo predictivo entre la existencia o no de conocimiento avanzado y las variables independientes mediante regresión logística. RESULTADOS: se encontraron diferencias en la puntuación media del nivel de conocimientos entre Parque-Somió y Calzada (p = 0.000) y Parque-Somió y Zarracina (p = 0.045), obteniendo mayor puntuación media la de Parque-Somió. Se observó una asociación entre el nivel de conocimientos y las variables medio de información utilizado (p = 0.018), edad (p = 0.036), zona básica de salud (p = 0.000), nivel educativo (p = 0.000) e historia previa de contacto estrecho (p = 0.004). CONCLUSIONES: el nivel de conocimientos avanzado se presenta sobre todo en las zonas básicas de salud con mayor nivel socioeconómico, población con nivel educativo alto, de 25 a 45 años, que se ha informado por su entorno y con historia previa de seguimiento por ser contacto estrecho.

Inhibitory effects of 6'-sialyllactose on angiotensin II-induced proliferation, migration, and osteogenic switching in vascular smooth muscle cells.

Excessive production and migration of vascular smooth muscle cells (VSMCs) are associated with vascular remodeling that causes vascular diseases, such as restenosis and hypertension. Angiotensin II (Ang II) stimulation is a key factor in inducing abnormal VSMC function. This study aimed to investigate the effects of 6'-sialyllactose (6'SL), a human milk oligosaccharide, on Ang II-stimulated cell proliferation, migration and osteogenic switching in rat aortic smooth muscle cells (RASMCs) and human aortic smooth muscle cells (HASMCs). Compared with the control group, Ang II increased cell proliferation by activating MAPKs, including ERK1/2/p90RSK/Akt/mTOR and JNK pathways. However, 6'SL reversed Ang II-stimulated cell proliferation and the ERK1/2/p90RSK/Akt/mTOR pathways in RASMCs and HASMCs. Moreover, 6'SL suppressed Ang II-stimulated cell cycle progression from G0/G1 to S and G2/M phases in RASMCs. Furthermore, 6'SL effectively inhibited cell migration by downregulating NF-κB-mediated MMP2/9 and VCAM-1 expression levels. Interestingly, in RASMCs, 6'SL attenuated Ang II-induced osteogenic switching by reducing the production of p90RSK-mediated c-fos and JNK-mediated c-jun, leading to the downregulation of AP-1-mediated osteopontin production. Taken together, our data suggest that 6'SL inhibits Ang II-induced VSMC proliferation and migration by abolishing the ERK1/2/p90RSK-mediated Akt and NF-κB signaling pathways, respectively, and osteogenic switching by suppressing p90RSK- and JNK-mediated AP-1 activity.