3'-Sialyllactose as an inhibitor of p65 phosphorylation ameliorates the progression of experimental rheumatoid arthritis

Review on bioproduction of sialylated human milk oligosaccharides: Synthesis methods, physiologic functions, and applications

Human milk oligosaccharides (HMOs) are crucial for promoting neonatal health, with sialylated oligosaccharides, a significant subclass, offering a variety of health benefits such as prebiotic effects, anti-inflammatory and antimicrobial properties, antiviral defense, and cognitive development support. Among these, 3'-sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL) have received "GRAS" status from the U.S. Food and Drug Administration and approval from the European Food Safety Authority for use as novel food additives in infant formula and supplements. This review focuses on the synthesis methods of sialylated human milk oligosaccharides (SHMOs), their functional properties, downstreaming developments and application technologies. Given the challenges associated with achieving sufficient availability for food and medical applications, the review emphasizes the viability and efficiency of various production strategies. The review also highlights recent research advancements and offers insights for optimizing large-scale production to support future applications in the food and pharmaceutical industries.

Daptomycin alleviates collagen-induced arthritis via suppressing inflammatory cytokines and NF-κB pathway

Rheumatoid arthritis (RA) is a chronic autoimmune disease, and its pathogenic factors include bacterial infection and immune inflammation. Daptomycin (DAP) is a cyclic lipopeptide that has been approved to treat skin infections, bacteremia and right-sided endocarditis due to its effective antibacterial effects against most Gram-positive pathogenic bacteria. Herein, we focus on whether DAP exerts anti-inflammatory activity on RA to expand DAP drug indications. Our studies are first time to evaluate anti-inflammatory effect and reveal its molecular pharmacological mechanism of DAP on lipopolysaccharide-activated macrophage and collagen-induced arthritis (CIA) mice. In vitro cytological studies show that 10 µg/mL DAP inhibits secretion of IL-1β, IL-6 and TNF-α to alleviate cell inflammation, and the phosphorylation level of p65 (p-p65) of RAW 264.7 cells is decreased under DAP exposure. Administration with 10 mg/kg/2d DAP via intravenous injection on CIA mice significantly reduces arthritis symptom by inhibiting p-p65 level and decreasing serum level of IL-6, IL-1β and TNF-α. Moreover, our study is the first time to reveal new immunomodulatory effects of DAP on RA, which provides a pharmacological basis for new clinical applications of DAP for other immune-related diseases except to bacterial infections.

The human milk oligosaccharide 3'sialyllactose reduces low-grade inflammation and atherosclerosis development in mice

Macrophages contribute to the induction and resolution of inflammation and play a central role in chronic low-grade inflammation in cardiovascular diseases caused by atherosclerosis. Human milk oligosaccharides (HMOs) are complex unconjugated glycans unique to human milk that benefit infant health and act as innate immune modulators. Here, we identify the HMO 3'sialyllactose (3'SL) as a natural inhibitor of TLR4-induced low-grade inflammation in macrophages and endothelium. Transcriptome analysis in macrophages revealed that 3'SL attenuates mRNA levels of a selected set of inflammatory genes and promotes the activity of liver X receptor (LXR) and sterol regulatory element binding protein-1 (SREBP1). These acute antiinflammatory effects of 3'SL were associated with reduced histone H3K27 acetylation at a subset of LPS-inducible enhancers distinguished by preferential enrichment for CCCTC-binding factor (CTCF), IFN regulatory factor 2 (IRF2), B cell lymphoma 6 (BCL6), and other transcription factor recognition motifs. In a murine atherosclerosis model, both s.c. and oral administration of 3'SL significantly reduced atherosclerosis development and the associated inflammation. This study provides evidence that 3'SL attenuates inflammation by a transcriptional mechanism to reduce atherosclerosis development in the context of cardiovascular disease.

A Novel BD2-Selective Inhibitor of BRDs Mitigates ROS Production and OA Pathogenesis

Bromodomain and extra-terminal domain (BET) family proteins regulate transcription and recognize lysine residues in histones. Selective BET inhibitors targeting one domain have attracted attention because they maintain normal physiological activities, whereas pan (nonselective) BET inhibitors do not. Osteoarthritis (OA) is a joint disorder characterized by cartilage degeneration for which no treatment currently exists. Here, we investigated whether the selective inhibition of BET proteins is an appropriate therapeutic strategy for OA. We focused on the development and characterization of 2-(4-(2-(dimethylamino)ethoxy)-3,5-dimethylphenyl)-5,7-dimethoxyquinazolin-4(3H)-one (BBC0906), a novel bromodomain 2 (BD2)-specific inhibitor designed to suppress OA progression. Using a DNA-encoded chemical library (DEL) screening approach, BBC0906 was identified because of its high affinity with the BD2 domain of BET proteins. BBC0906 effectively reduced reactive oxygen species (ROS) production and suppressed catabolic factor expression in chondrocytes in vitro. Moreover, in an OA mouse model induced by the destabilization of the medial meniscus (DMM), BBC0906 intra-articular injection attenuated cartilage degradation and alleviated OA. Importantly, BBC0906 selectively inhibits the BD2 domain, thus minimizing its potential side effects. We highlighted the therapeutic potential of targeting BET proteins to modulate oxidative stress and suppress cartilage degradation in OA. BBC0906 is a promising candidate for OA treatment, offering improved safety and efficacy.

Tisochrysis lutea Fucoxanthin Suppresses NF-κB, JNK, and p38-Associated MMP Expression in Arthritis Pathogenesis via Antioxidant Activity

Tisochrysis lutea is a highly nutritious marine microalga that has various applications in aquaculture and biotechnology. However, the effects of T. lutea extract (TLE) on osteoarthritis (OA) pathogenesis remain unexplored. In this study, we aimed to determine the effects of TLE on OA development. We found that TLE inhibits the expression of matrix metalloproteinases (MMPs) and reactive oxygen species (ROS) activity in an OA mouse model generated by the destabilization of the medial meniscus (DMM) surgery. In vivo assays of the OA model mice demonstrated that TLE has a protective effect against cartilage destruction by inhibiting MMP3 and MMP13 expression. To enable the medical use of TLE, the components of TLE were characterized using high-performance liquid chromatography (HPLC) analysis. Interestingly, we found that Fucoxanthin accounts for 41.2% of TLE and showed anti-catabolic and antioxidant effects under IL-1β-treated in vitro conditions. RNA sequencing analysis showed that fucoxanthin decreased p38, NF-κB, and JNK signaling pathway gene expression, all of which are activated by IL-1β. Furthermore, in vivo analysis showed that fucoxanthin inhibited the IL-1β-stimulated phosphorylation of p65, JNK, and p38. These results highlight new possibilities for the use of TLE as a source of fucoxanthin, an antioxidant, for OA treatment.

Tacrolimus-loaded chitosan-based nanoparticles as an efficient topical therapeutic for the effective treatment of atopic dermatitis symptoms

Atopic dermatitis (AD) is a chronic cutaneous disease with a complex underlying mechanism, and it cannot be completely cured. Thus, most treatment strategies for AD aim at relieving the symptoms. Although corticosteroids are topically applied to alleviate AD, adverse side effects frequently lead to the withdrawal of AD therapy. Tacrolimus (TAC), a calcineurin inhibitor, has been used to treat AD, but its high molecular weight and insolubility in water hinder its skin permeability. Herein, we developed and optimized TAC-loaded chitosan-based nanoparticles (TAC@CNPs) to improve the skin permeability of TAC by breaking the tight junctions in the skin. The prepared nanoparticles were highly loadable and efficient and exhibited appropriate characteristics for percutaneous drug delivery. TAC@CNP was stable for 4 weeks under physiological conditions. CNP released TAC in a controlled manner, with enhanced skin penetration observed. In vitro experiments showed that CNP was non-toxic to keratinocyte (HaCaT) cells, and TAC@CNP dispersed in an aqueous solution was as anti-proliferative as TAC solubilized in a good organic solvent. Importantly, an in vivo AD mouse model revealed that topical TAC@CNP containing ~1/10 of the dose of TAC found in commercially used Protopic® Ointment exhibited similar anti-inflammatory activity to that of the commercial product. TAC@CNP represents a potential therapeutic strategy for the management of AD.

Highly efficient biosynthesis of 3'-sialyllactose in engineered Escherichia coli

3'-Sialyllactose (3'-SL), one of the abundant and important sialylated human milk oligosaccharides, is an emerging food ingredient used in infant formula milk. We previously developed an efficient route for 3'-SL biosynthesis in metabolically engineered Escherichia coli BL21(DE3). Here, several promising α2,3-sialyltransferases were re-evaluated from the byproduct synthesis perspective. The α2,3-sialyltransferase from Neisseria meningitidis MC58 (NST) with great potential and the least byproducts was selected for subsequent molecular modification. Computer-assisted mutation sites combined with a semi-rational modification were designed and performed. A combination of two mutation sites (P120H/N113D) of NST was finally confirmed as the best one, which significantly improved 3'-SL biosynthesis, with extracellular titers of 24.5 g/L at 5-L fed-batch cultivations. When NST-P120H/N113D was additionally integrated into the genome of host EZAK (E. coli BL21(DE3)ΔlacZΔnanAΔnanT), the final strain generated 32.1 g/L of extracellular 3'-SL in a 5-L fed-batch fermentation. Overall, we underscored the existence of by-products and improved 3'-SL production by engineering N. meningitidis α2,3-sialyltransferase.

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.

3'-Sialyllactose alleviates bone loss by regulating bone homeostasis

Osteoporosis is a common skeletal disease that results in an increased risk of fractures. However, there is no definitive cure, warranting the development of potential therapeutic agents. 3'-Sialyllactose (3'-SL) in human milk regulates many biological functions. However, its effect on bone metabolism remains unknown. This study aimed to investigate the molecular mechanisms underlying the effect of 3'-SL on bone homeostasis. Treatment of human bone marrow stromal cells (hBMSCs) with 3'-SL enhanced osteogenic differentiation and inhibited adipogenic differentiation of hBMSCs. RNA sequencing showed that 3'-SL enhanced laminin subunit gamma-2 expression and promoted osteogenic differentiation via the phosphatidylinositol 3‑kinase/protein kinase B signaling pathway. Furthermore, 3'-SL inhibited the receptor activator of nuclear factor κB ligand-induced osteoclast differentiation of bone marrow-derived macrophages through the nuclear factor κB and mitogen‑activated protein kinase signaling pathway, ameliorated osteoporosis in ovariectomized mice, and positively regulated bone remodeling. Our findings suggest 3'-SL as a potential drug for osteoporosis.

[Human milk oligosaccharides play major roles in child development and future health]

Human milk oligosaccharides (HMO) represent the third largest component of human breast milk (BM). The BM level is comprised between 5 to 20 g per liter and they have a great structural complexity with more than 150 HMO characterized to date. In this review, we present a summary of the main experimental and clinical data that have demonstrated their multiple biological roles in infants such as for gut development, microbiota, immune protection and neurodevelopment. Some HMO-enriched infant formulas are available yet, even if their benefits on the infant health remain to be confirmed. Further researches could allow therapeutic use in preterm newborns or in infants with intestinal diseases. Experimental data suggest that they could also be used in the prevention of some chronic diseases with immunometabolic or neurodevelopmental components.

Human Milk Oligosaccharides in Maternal Serum Respond to Oral Glucose Load and Are Associated with Insulin Sensitivity

(1) Background: Pregnancy presents a challenge to maternal glucose homeostasis; suboptimal adaptations can lead to gestational diabetes mellitus (GDM). Human milk oligosaccharides (HMOs) circulate in maternal blood in pregnancy and are altered with GDM, suggesting influence of glucose homeostasis on HMOs. We thus assessed the HMO response to glucose load during an oral glucose tolerance test (OGTT) and investigated HMO associations with glucose tolerance/insulin sensitivity in healthy pregnant women. (2) Methods: Serum of 99 women, collected at 0 h, 1 h and 2 h during a 75 g OGTT at 24-28 gestational weeks was analyzed for HMOs (2'FL, 3'SLN, LDFT, 3'SL) by HPLC; plasma glucose, insulin and C-peptide were analyzed by standard biochemistry methods. (3) Results: Serum 3'SL concentrations significantly increased from fasting to 1 h after glucose load, while concentrations of the other HMOs were unaltered. Higher 3'SL at all OGTT time points was associated with a generally more diabetogenic profile, with higher hepatic insulin resistance (HOMA-IR), lower insulin sensitivity (Matsuda index) and higher insulin secretion (C-peptide index 1). (4) Conclusions: Rapid increase in serum 3'SL post-oral glucose load (fasted-fed transition) indicates utilization of plasma glucose, potentially for sialylation of lactose. Associations of sialylated HMOs with a more diabetogenic profile suggest sustained adaptations to impaired glucose homeostasis in pregnancy. Underlying mechanisms or potential consequences of observed HMO changes remain to be elucidated.

CCL21/CCR7 axis as a therapeutic target for autoimmune diseases

Chemokine receptor 7 (CCR7) is a G protein-coupled receptor containing 7 transmembrane domains that is expressed on various cells, such as naive T/B cells, central memory T cells, regulatory T cells, immature/mature dendritic cells (DCs), natural killer cells, and a minority of tumor cells. Chemokine ligand 21 (CCL21) is the known high-affinity ligand that binds to CCR7 and drives cell migration in tissues. CCL21 is mainly produced by stromal cells and lymphatic endothelial cells, and its expression is significantly increased under inflammatory conditions. Genome-wide association studies (GWAS) have shown a strong association between CCL21/CCR7 axis and disease severity in patients with rheumatoid arthritis, sjogren's syndrome, systemic lupus erythematosus, polymyositis, ankylosing spondylitis, and asthma. Disrupting CCL21/CCR7 interaction with antibodies or inhibitors prevents the migration of CCR7-expressing immune and non-immune cells at the site of inflammation and reduces disease severity. This review emphasizes the importance of the CCL21 /CCR7 axis in autoimmune diseases and evaluates its potential as a novel therapeutic target for these conditions.

MicroRNA-143-3p ameliorates collagen-induced arthritis by polarizing naive CD4+ T cells into Treg cells

BACKGROUND

Rheumatoid arthritis (RA) is a persistent and systemic autoimmunity disease. The abnormal differentiation of Treg cells is important in pathogenesis. Despite previous studies showed that microRNAs (miRNAs, miR) are pivotal modulators of Treg cells, the effect of miRNAs on Treg cell differentiation and function is not clear. Our study wants to reveal the relationship of miR-143-3p with the differentiative ability and biofunction of Treg cells during the development of RA.

METHODS

The Expressing level of miR-143-3p and cell factor generation in peripheral blood (PB) of RA sufferers were identified by ELISA or RT-qPCR. The roles of miR-143-3p in Treg cell differentiation were studied via ShRNA/lentivirus transfection. Male DBA/1 J mice were separated into control, model, control mimics, and miR-143-3p mimics groups to analyze the anti-arthritis efficacy, the differentiative ability of Treg cells, and the expression level of miR-143-3p.

RESULTS

Our team discovered that the Expressing level of miR-143-3p was related to RA disease activities in a negative manner, and remarkably related to antiinflammation cell factor IL-10. In vitro, the expression of miR-143-3p in the CD4⁺ T cells upregulated the percentage of CD4⁺ CD25⁺ Fxop3⁺ cells (Tregs) and forkhead box protein 3 (Foxp3) mRNA expression. Evidently, miR-143-3p mimic intervention considerably upregulated the content of Treg cells in vivo, validly avoided CIA progression, and remarkably suppressed the inflammatory events of joints in mice.

CONCLUSION

Our findings indicated that miR-143-3p could ameliorate CIA through polarizing naive CD4⁺ T cells into Treg cells, which may be a novel strategy to treat autoimmune diseases such as RA.

Recent progress on health effects and biosynthesis of two key sialylated human milk oligosaccharides, 3'-sialyllactose and 6'-sialyllactose

Human milk oligosaccharides (HMOs), the third major solid component in breast milk, are recognized as the first prebiotics for health benefits in infants. Sialylated HMOs are an important type of HMOs, accounting for approximately 13% of total HMOs. 3'-Sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL) are two simplest sialylated HMOs. Both SLs display promising prebiotic effects, especially in promoting the proliferation of bifidobacteria and shaping the gut microbiota. SLs exhibit several health effects, including antiadhesive antimicrobial ability, antiviral activity, prevention of necrotizing enterocolitis, immunomodulatory activity, regulation of intestinal epithelial cell response, promotion of brain development, and cognition improvement. Both SLs have been approved as "Generally Recognized as Safe" by the American Food and Drug Administration and are commercially added to infant formula. The biosynthesis of SLs using enzymatic or microbial approaches has been widely studied. The enzymatic synthesis of SLs can be realized by two types of enzymes, sialidases with trans-sialidase activity and sialyltransferases. Microbial synthesis can be achieved by the multiple recombinant bacteria in one-pot reaction, which express the enzymes involved in SL synthesis pathways separately or in combination, or by metabolically engineered strains in a fermentation process. In this article, the physiological properties of 3'-SL and 6'-SL are summarized in detail and the biosynthesis of these SLs via enzymatic and microbial synthesis is comprehensively reviewed.

N-benzyl-N-methyldecan-1-amine and its derivative mitigate 2,4- dinitrobenzenesulfonic acid-induced colitis and collagen-induced rheumatoid arthritis

As our previous study revealed that N-benzyl-N-methyldecan-1-amine (BMDA), a new molecule originated from Allium sativum, exhibits anti-neoplastic activities, we herein explored other functions of the compound and its derivative [decyl-(4-methoxy-benzyl)-methyl-amine; DMMA] including anti-inflammatory and anti-oxidative activities. Pretreatment of THP-1 cells with BMDA or DMMA inhibited tumor necrosis factor (TNF)-α and interleukin (IL)-1β production, and blocked c-jun terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), MAPKAP kinase (MK)2 and NF-κΒ inflammatory signaling during LPS stimulation. Rectal treatment with BMDA or DMMA reduced the severity of colitis in 2,4-dinitrobenzenesulfonic acid (DNBS)-treated rat. Consistently, administration of the compounds decreased myeloperoxidase (MPO) activity (representing neutrophil infiltration in colonic mucosa), production of inflammatory mediators such as cytokine-induced neutrophil chemoattractant (CINC)-3 and TNF-α, and activation of JNK and p38 MAPK in the colon tissues. In addition, oral administration of these compounds ameliorated collagen-induced rheumatoid arthritis (RA) in mice. The treatment diminished the levels of inflammatory cytokine transcripts, and protected connective tissues through the expression of anti-oxidation proteins such as nuclear factor erythroid-related factor (Nrf)2 and heme oxygenase (HO)1. Additionally, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels did not differ between the BMDA- or DMMA-treated and control animals, indicating that the compounds do not possess liver toxicity. Taken together, these findings propose that BMDA and DMMA could be used as new drugs for curing inflammatory bowel disease (IBD) and RA.

Chemoproteomic mapping of human milk oligosaccharide (HMO) interactions in cells

Human milk oligosaccharides (HMOs) are a family of unconjugated soluble glycans found in human breast milk that exhibit a myriad of biological activity. While recent studies have uncovered numerous biological functions for HMOs (antimicrobial, anti-inflammatory & probiotic properties), the receptors and protein binding partners involved in these processes are not well characterized. This can be attributed largely in part to the low affinity and transient nature of soluble glycan-protein interactions, precluding the use of traditional characterization techniques to survey binding partners in live cells. Here, we present the use of synthetic photoactivatable HMO probes to capture, enrich and identify HMO protein targets in live cells using mass spectrometry-based chemoproteomics. Following initial validation studies using purified lectins, we profiled the targets of HMO probes in live mouse macrophages. Using this strategy, we mapped hundreds of HMO binding partners across multiple cellular compartments, including many known glycan-binding proteins as well as numerous proteins previously not known to bind glycans. We expect our findings to inform future investigations of the diverse roles of how HMOs may regulate protein function.

Current Advances in Structure-Function Relationships and Dose-Dependent Effects of Human Milk Oligosaccharides

HMOs (human milk oligosaccharides) are the third most important nutrient in breast milk. As complex glycans, HMOs play an important role in regulating neonatal intestinal immunity, resisting viral and bacterial infections, displaying anti-inflammatory characteristics, and promoting brain development. Although there have been some previous reports of HMOs, a detailed literature review summarizing the structure-activity relationships and dose-dependent effects of HMOs is lacking. Hence, after introducing the structures and synthetic pathways of HMOs, this review summarizes and categorizes identified structure-function relationships of HMOs. Differential mechanisms of different structural HMOs utilization by microorganisms are summarized. This review also emphasizes the recent advances in the interactions between different health benefits and the variance of dosage effect based on in vitro cell tests, animal experiments, and human intervention studies. The potential relationships between the chemical structure, the dosage selection, and the physiological properties of HMOs as functional foods are vital for further understanding of HMOs and their future applications.

Dynamic synovial fibroblasts are modulated by NBCn1 as a potential target in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by aggressive fibroblast-like synoviocytes (FLSs) and pannus formation. Various therapeutic strategies have been developed against inflammatory cytokines in RA in recent decades. Based on the migratory features of FLSs, we examined whether modulation of the migratory module attenuates RA severity. In this study, inflamed synovial fluid-stimulated FLSs exhibited enhanced migration and migratory apparatus expression, and sodium bicarbonate cotransporter n1 (NBCn1) was identified in primary cultured RA-FLSs for the first time. The NBC inhibitor S0859 attenuated the migration of FLSs induced with synovial fluid from patients with RA or with TNF-α stimulation. Inhibition of NBCs with S0859 in a collagen-induced arthritis (CIA) mouse model reduced joint swelling and destruction without blood, hepatic, or renal toxicity. Primary FLSs isolated from the CIA-induced mouse model also showed reduced migration in the presence of S0859. Our results suggest that inflammatory mediators in synovial fluid, including TNF-α, recruit NBCn1 to the plasma membrane of FLSs to provide dynamic properties and that modulation of NBCn1 could be developed into a therapeutic strategy for RA.

Therapeutic effect of intra-articular injected 3'-sialyllactose on a minipig model of rheumatoid arthritis induced by collagen

Background

Rheumatoid arthritis (RA) is a chronic inflammatory disease of joint, but there is no known cure.

3′-sialyllactose (3′-SL) is an oligosaccharide that is abundant in breast milk of mammals, and has anti-inflammatory properties. However, the efficacy of 3′-SL on RA remains unclear. The objective of the present study was to evaluate the therapeutic effect of 3′-SL after it was directly injected into the knee joint cavity of a RA minipig model.

Results

Minipig RA model was induced by intra-articular injection of bovine type II collagen emulsified with complete or incomplete Freund’s adjuvant into left knee joint. In clinical assessment, lameness and swelling of the hindlimb and increased knee joint width were observed in all animals. After the onset of arthritis, 3′-SL (0, 2, 10, and 50 mg/kg) was directly administered to the left knee joint cavity once a week for 4 weeks. Compared to the vehicle control group, no significant difference in macroscopic observation of the synovial pathology or the expression of inflammation-related genes (IL-1β, TNF-α, and COX2) in the synovial membrane of the knee joint was found. In microscopic observation, cell cloning of the articular cartilage was significantly reduced in proportion to the concentration of 3′-SL administered.

Conclusions

Our results suggest that intra-articular injected 3′-SL had a therapeutic effect on collagen-induced arthritis at the cellular level with potential as a medication for RA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42826-022-00119-2.

Augmented ERAD (ER-associated degradation) activity in chondrocytes is necessary for cartilage development and maintenance

Chondrocytes secrete massive extracellular matrix (ECM) molecules that are produced, folded, and modified in the endoplasmic reticulum (ER). Thus, the ER-associated degradation (ERAD) complex-which removes misfolded and unfolded proteins to maintain proteostasis in the ER- plays an indispensable role in building and maintaining cartilage. Here, we examined the necessity of the ERAD complex in chondrocytes for cartilage formation and maintenance. We show that ERAD gene expression is exponentially increased during chondrogenesis, and disruption of ERAD function causes severe chondrodysplasia in developing embryos and loss of adult articular cartilage. ERAD complex malfunction also causes abnormal accumulation of cartilage ECM molecules and subsequent chondrodysplasia. ERAD gene expression is decreased in damaged cartilage from patients with osteoarthritis (OA), and disruption of ERAD function in articular cartilage leads to cartilage destruction in a mouse OA model.

Studies and Application of Sialylated Milk Components on Regulating Neonatal Gut Microbiota and Health

Breast milk is rich in sialic acids (SA), which are commonly combined with milk oligosaccharides and glycoconjugates. As a functional nutrient component, SA-containing milk components have received increasing attention in recent years. Sialylated human milk oligosaccharides (HMOs) have been demonstrated to promote the growth and metabolism of beneficial gut microbiota in infants, bringing positive outcomes to intestinal health and immune function. They also exhibit antiviral and bacteriostatic activities in the intestinal mucosa of new-borns, thereby inhibiting the adhesion of pathogens to host cells. These properties play a pivotal role in regulating the intestinal microbial ecosystem and preventing the occurrence of neonatal inflammatory diseases. In addition, some recent studies also support the promoting effects of sialylated HMOs on neonatal bone and brain development. In addition to HMOs, sialylated glycoproteins and glycolipids are abundant in milk, and are also critical to neonatal health. This article reviews the current research progress in the regulation of sialylated milk oligosaccharides and glycoconjugates on neonatal gut microbiota and health.

ACLY Nuclear Translocation in Human Macrophages Drives Proinflammatory Gene Expression by NF-κB Acetylation

Macrophage stimulation by pathogen-associated molecular patterns (PAMPs) like lipopolysaccharide (LPS) or lipoteichoic acid (LTA) drives a proinflammatory phenotype and induces a metabolic reprogramming to sustain the cell’s function. Nevertheless, the relationship between metabolic shifts and gene expression remains poorly explored. In this context, the metabolic enzyme ATP citrate lyase (ACLY), the producer of citrate-derived acetyl-coenzyme A (CoA), plays a critical role in supporting a proinflammatory response. Through immunocytochemistry and cytosol–nucleus fractionation, we found a short-term ACLY nuclear translocation. Protein immunoprecipitation unveiled the role of nuclear ACLY in NF-κB acetylation and in turn its full activation in human PBMC-derived macrophages. Notably, sepsis in the early hyperinflammatory phase triggers ACLY-mediated NF-κB acetylation. The ACLY/NF-κB axis increases the expression levels of proinflammatory genes, including SLC25A1—which encodes the mitochondrial citrate carrier—and ACLY, thus promoting the existence of a proinflammatory loop involving SLC25A1 and ACLY genes.

Multifunctional Benefits of Prevalent HMOs: Implications for Infant Health

Breastfeeding is the best source of nutrition during infancy and is associated with a broad range of health benefits. However, there remains a significant and persistent need for innovations in infant formula that will allow infants to access a wider spectrum of benefits available to breastfed infants. The addition of human milk oligosaccharides (HMOs) to infant formulas represents the most significant innovation in infant nutrition in recent years. Although not a direct source of calories in milk, HMOs serve as potent prebiotics, versatile anti-infective agents, and key support for neurocognitive development. Continuing improvements in food science will facilitate production of a wide range of HMO structures in the years to come. In this review, we evaluate the relationship between HMO structure and functional benefits. We propose that infant formula fortification strategies should aim to recapitulate a broad range of benefits to support digestive health, immunity, and cognitive development associated with HMOs in breastmilk. We conclude that acetylated, fucosylated, and sialylated HMOs likely confer important health benefits through multiple complementary mechanisms of action.

Self-assembled hyaluronic acid nanoparticles for osteoarthritis treatment

Although osteoarthritis (OA) is the most prevalent degenerative joint disease, there is no effective disease-modifying therapy. We report an empty self-assembled hyaluronic acid nanoparticle (HA-NP) as a potential therapeutic agent for OA treatment. In mouse primary articular chondrocytes, HA-NPs blocked the receptor-mediated cellular uptake of free low-molecular-weight HA, and the cellular uptake of HA-NPs increased by ectopic expression of CD44, using an adenoviral delivery system (Ad-Cd44). HA-NP showed in vitro resistance to digestion with hyaluronidase and in vivo long-term retention ability in knee joint, compared with free high-molecular-weight (HMW) HA. CD44 expression increased in the damaged articular cartilage of patients and mice with OA. Ad-Cd44 infection and IL-1β treatment induced in vitro phenotypes of OA by enhancing catabolic gene expression in primary articular chondrocytes, and these effects were attenuated by HA-NP, but not HMW HA. Both Cd44 deficiency and intra-articular injection of HA-NP protected joint cartilage against OA development in the OA mouse model. NF-κB was found to mediate CD44-induced catabolic factor expression and HA-NP inhibited CD44-induced NF-κB activation in chondrocytes. Our results identify an empty HA-NP as a potential therapeutic agent targeting CD44 for OA treatment, and the CD44-NF-κB-catabolic gene axis as an underlying mechanism of destructive cartilage disorders.

ZhiJingSan Inhibits Osteoclastogenesis via Regulating RANKL/NF-κB Signaling Pathway and Ameliorates Bone Erosion in Collagen-Induced Mouse Arthritis

Bone erosion is the most evident pathological condition of rheumatoid arthritis (RA), which is the main cause of joint deformities and disability in RA patients. At present, the conventional RA drugs have not achieved satisfactory effect in improving bone erosion. ZhiJingSan (ZJS), which is a traditional Chinese prescription composed of scolopendra (dried body of Scolopendra subspinipes mutilans L. Koch, scolopendridae) and scorpion (dried body of Buthus martensii Karsch, Buthus), exhibits anti-rheumatism, analgesic and joint deformities improvement effects. This study aimed to assess the therapeutic effect of ZJS on RA bone erosion and to elucidate the underlying mechanism. The effect of ZJS on RA bone erosion was investigated in a murine model of bovine collagen-induced arthritis (CIA), and the underlying mechanism was investigated in vitro in an osteoclast differentiation cell model. Administration of ZJS delayed the onset of arthritis, alleviated joint inflammation, and attenuated bone erosion in the CIA mice. Meanwhile, ZJS decreased the serum levels of TNF-α, IL-6, and anti-bovine collagen II-specific antibodies. Furthermore, ZJS treatment reduced the number of osteoclasts and the expression of cathepsin K in the ankle joints of CIA mice. ZJS also inhibited receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation and the expression of MMP9 and cathepsin K in vitro. Mechanistically, ZJS blocked RANKL-induced p65 phosphorylation, nucleation, and inhibited the expression of downstream NFATc1 and c-Fos in bone marrow-derived macrophages (BMMs). Taken together, ZJS exerts a therapeutic effect on bone erosion in CIA mice by inhibiting RANKL/NF-κB-mediated osteoclast differentiation, which suggested that ZJS is a promising prescription for treating RA bone erosion.

MicroRNA-26b-5p alleviates murine collagen-induced arthritis by modulating Th17 cell plasticity

Rheumatoid arthritis (RA) is a chronic autoimmune disease, and the abnormal differentiation of IL-17-producing T helper (Th17) cells is an important factor in the pathogenesis. Previous studies have shown that microRNAs (miRNAs, miR) act as key regulators of Th17 cells. However, the effects of miRNAs on Th17 cell differentiation and plasticity in RA are not clear. In this study, not only low miR-26b-5p expression and high IL-17A level were observed in the peripheral blood of RA patients, but also the negative correlation between miR-26b-5p and IL-17A was explored. The changes in collagen-induced arthritis (CIA) mice were consistent with those in RA patients. The results of in vitro experiments showed that miR-26b-5p mainly inhibited the initial differentiation of Th17 cells but did not impact the differentiation of induced-Treg into Th17-like cells. Meanwhile, miR-26b-5p mimics treatment alleviated inflammatory responses and reduced Th17 proportion in CIA mice. These results indicated that miR-26b-5p could alleviate the development of mice CIA by inhibiting the excessive Th17 cells, and that miR-26b-5p could modulate the plasticity of Th17 cell differentiation in RA, mainly block the initial differentiation. This may provide a novel strategy for the clinical treatment of RA.

3'-Sialyllactose Protects SW1353 Chondrocytic Cells From Interleukin-1β-Induced Oxidative Stress and Inflammation

Osteoarthritis (OA) is a major degenerative joint disease. Oxidative stress and inflammation play key roles in the pathogenesis of OA. 3'-Sialyllactose (3'-SL) is derived from human milk and is known to regulate a variety of biological functions related to immune homeostasis. This study aimed to investigate the therapeutic mechanisms of 3'-SL in interleukin-1β (IL-1β)-treated SW1353 chondrocytic cells. 3'-SL potently suppressed IL-1β-induced oxidative stress by increasing the levels of enzymatic antioxidants. 3'-SL significantly reversed the IL-1β mediated expression levels of reactive oxygen species in IL-1β-stimulated chondrocytic cells. In addition, 3'-SL could reverse the increased levels of inflammatory markers such as nitrite, prostaglandin E2, inducible nitric oxide synthase, cyclooxygenase-2, IL-1β, and IL-6 in IL-1β-stimulated chondrocytic cells. Moreover, 3'-SL significantly inhibited the apoptotic process, as indicated by the downregulation of the pro-apoptotic protein Bax, upregulation of the anti-apoptotic protein Bcl-2 expression, and significant reduction in the number of TUNEL-positive cells in the IL-1β-treated chondrocytic cells. Furthermore, 3'-SL reversed cartilage destruction by decreasing the release of matrix metalloproteinases (MMP), such as MMP1, MMP3, and MMP13. In contrast, 3'-SL significantly increased the expression levels of matrix synthesis proteins, such as collagen II and aggrecan, in IL-1β-treated chondrocytic cells. 3'-SL dramatically suppressed the activation of mitogen-activated protein kinases (MAPK) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways, which are related to the pathogenesis of OA. Taken together, our data suggest that 3'-SL alleviates IL-1β-induced OA pathogenesis via inhibition of activated MAPK and PI3K/AKT/NF-κB signaling cascades with the downregulation of oxidative stress and inflammation. Therefore, 3'-SL has the potential to be used as a natural compound for OA therapy owing to its ability to activate the antioxidant defense system and suppress inflammatory responses.

Current Perspective of Sialylated Milk Oligosaccharides in Mammalian Milk: Implications for Brain and Gut Health of Newborns

Human milk oligosaccharides (HMOs) are the third most abundant solid component after lactose and lipids of breast milk. All mammal milk contains soluble oligosaccharides, including neutral milk oligosaccharides (NMOs) without sialic acid (Sia) moieties and acidic oligosaccharides or sialylated milk oligosaccharides (SMOs) with Sia residues at the end of sugar chains. The structural, biological diversity, and concentration of milk oligosaccharides in mammalian milk are significantly different among species. HMOs have multiple health benefits for newborns, including development of immune system, modification of the intestinal microbiota, anti-adhesive effect against pathogens, and brain development. Most infant formulas lack oligosaccharides which resemble HMOs. Formula-fed infants perform poorly across physical and psychological wellbeing measures and suffer health disadvantages compared to breast-fed infants due to the differences in the nutritional composition of breast milk and infant formula. Of these milk oligosaccharides, SMOs are coming to the forefront of research due to the beneficial nature of Sia. This review aims to critically discuss the current state of knowledge of the biology and role of SMOs in human milk, infant formula milks, and milk from several other species on gut and brain health of human and animal offspring.

Therapeutic Single Compounds for Osteoarthritis Treatment

Osteoarthritis (OA) is an age-related degenerative disease for which an effective disease-modifying therapy is not available. Natural compounds derived from plants have been traditionally used in the clinic to treat OA. Over the years, many studies have explored the treatment of OA using natural extracts. Although various active natural extracts with broad application prospects have been discovered, single compounds are more important for clinical trials than total natural extracts. Moreover, although natural extracts exhibit minimal safety issues, the cytotoxicity and function of all single compounds in a total extract remain unclear. Therefore, understanding single compounds with the ability to inhibit catabolic factor expression is essential for developing therapeutic agents for OA. This review describes effective single compounds recently obtained from natural extracts and the possibility of developing therapeutic agents against OA using these compounds.

Seomae mugwort and jaceosidin attenuate osteoarthritic cartilage damage by blocking IκB degradation in mice

Seomae mugwort, a Korean native variety of Artemisia argyi, exhibits physiological effects against various diseases. However, its effects on osteoarthritis (OA) are unclear. In this study, a Seomae mugwort extract prevented cartilage destruction in an OA mouse model. In vitro and ex vivo analyses revealed that the extract suppressed MMP3, MMP13, ADAMTS4 and ADAMTS5 expression induced by IL-1β, IL-6 and TNF-α and inhibited the loss of extracellular sulphated proteoglycans. In vivo analysis revealed that oral administration of the extract suppressed DMM-induced cartilage destruction. We identified jaceosidin in Seomae mugwort and showed that this compound decreased MMP3, MMP13, ADAMTS4 and ADAMTS5 expression levels, similar to the action of the Seomae mugwort extract in cultured chondrocytes. Interestingly, jaceosidin and eupatilin combined had similar effects to Seomae mugwort in the DMM-induced OA model. Induction of IκB degradation by IL-1β was blocked by the extract and jaceosidin, whereas JNK phosphorylation was only suppressed by the extract. These results suggest that the Seomae mugwort extract and jaceosidin can attenuate cartilage destruction by suppressing MMPs, ADAMTS4/5 and the nuclear factor-κB signalling pathway by blocking IκB degradation. Thus, the findings support the potential application of Seomae mugwort, and particularly jaceosidin, as natural therapeutics for OA.

A mimetic peptide of α2,6-sialyllactose promotes neuritogenesis

Oxidative stress contributes to the pathogenesis of neurodegenerative diseases. With the aim to find reagents that reduce oxidative stress, a phage display library was screened for peptides mimicking α2,6-sialyllactose (6'-SL), which is known to beneficially influence neural functions. Using Sambucus nigra lectin, which specifically binds to 6'-SL, we screened a phage display library and found a peptide comprising identical sequences of 12 amino acids. Mimetic peptide, reverse peptide and scrambled peptide were tested for inhibition of 6'-SL binding to the lectin. Indeed, lectin binding to 6'-SL was inhibited by the most frequently identified mimetic peptide, but not by the reverse or scrambled peptides, showing that this peptide mimics 6'-SL. Functionally, mimetic peptide, but not the reverse or scrambled peptides, increased viability and expression of neural cell adhesion molecule L1 in SK-N-SH human neuroblastoma cells, and promoted survival and neurite outgrowth of cultured mouse cerebellar granule neurons challenged by H₂O₂-induced oxidative stress. The combined results indicate that the 6'-SL mimetic peptide promotes neuronal survival and neuritogenesis, thus raising hopes for the treatment of neurodegenerative diseases. This study was approved by the Medical Ethics Committee of Shantou University Medical College, China (approval No. SUMC 2014-004) on February 20, 2014.

3'-Sialyllactose prebiotics prevents skin inflammation via regulatory T cell differentiation in atopic dermatitis mouse models

3'-Sialyllactose (3'-SL), a natural prebiotic, maintains immune homeostasis and exerts anti-inflammatory and anti-arthritic effects. Although regulatory T cells (Tregs) prevent excessive inflammation and maintain immune tolerance, the effect of 3'-SL on Treg regulation is unclear. This study aimed to investigate the effect of 3'-SL on Treg responses in atopic dermatitis (AD) pathogenesis. Oral administration of 3'-SL reduced AD-like symptoms such as ear, epidermal, and dermal thickness in repeated topical application of house dust mites (HDM) and 2,4-dinitrochlorobenzene (DNCB). 3'-SL inhibited IgE, IL-1β, IL-6, and TNF-α secretion and markedly downregulated AD-related cytokines including IL-4, IL-5, IL-6, IL-13, IL-17, IFN-γ, TNF-α, and Tslp through regulation of NF-κB in ear tissue. Additionally, in vitro assessment of Treg differentiation revealed that 3'-SL directly induced TGF-β-mediated Treg differentiation. Furthermore, 3'-SL administration also ameliorated sensitization and elicitation of AD pathogenesis by suppressing mast cell infiltration and production of IgE and pro-inflammatory cytokines in mouse serum by mediating the Treg response. Furthermore, Bifidobacterium population was also increased by 3'-SL administration as prebiotics. Our data collectively show that 3'-SL has therapeutic effects against AD progression by inducing Treg differentiation, downregulating AD-related cytokines, and increasing the Bifidobacterium population.

NR1D1 modulates synovial inflammation and bone destruction in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial hyperplasia, pannus formation, and cartilage and bone destruction. Nuclear receptor subfamily 1 group D member 1 (NR1D1) functions as a transcriptional repressor and plays a vital role in inflammatory reactions. However, whether NR1D1 is involved in synovial inflammation and joint destruction during the pathogenesis of RA is unknown. In this study, we found that NR1D1 expression was increased in synovial tissues from patients with RA and decreased in RA Fibroblast-like synoviocytes (FLSs) stimulated with IL-1β in vitro. We showed that NR1D1 activation decreased the expression of proinflammatory cytokines and matrix metalloproteinases (MMPs), while NR1D1 silencing exerted the opposite effect. Furthermore, NR1D1 activation reduced reactive oxygen species (ROS) generation and increased the production of nuclear transcription factor E2-related factor 2 (Nrf2)-associated enzymes. Mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways were blocked by the NR1D1 agonist SR9009 but activated by NR1D1 silencing. NR1D1 activation also inhibited M1 macrophage polarization and suppressed osteoclastogenesis and osteoclast-related genes expression. Treatment with NR1D1 agonist SR9009 in collagen-induced arthritis (CIA) mouse significantly suppressed the hyperplasia of synovial, infiltration of inflammatory cell and destruction of cartilage and bone. Our findings demonstrate an important role for NR1D1 in RA and suggest its therapeutic potential.

Alleviation of Synovial Inflammation of Juanbi-Tang on Collagen-Induced Arthritis and TNF-Tg Mice Model

Rheumatoid arthritis (RA) is a chronic autoimmune disease that is primarily characterized by synovial inflammation. In this study, we found that a traditional Chinese decoction, Juanbi-Tang (JBT), JBT attenuated the symptoms of collagen-induced arthritis (CIA) mice and in tumor necrosis factor transgenic (TNF-Tg) mice by attenuating the arthritis index and hind paw thickness. According to histopathological staining of ankle sections, JBT significantly decreased the area of inflammation and reduced bone destruction of ankle joints in both these two types of mice. Moreover, decreased tartaric acid phosphatase-positive osteoclasts were observed in the JBT group compared with those found in the control group. We also revealed that JBT suppressed monocytes and T cells as well as the production of CCL2, CCR6, and CXCR3 ligands. We next used high-performance liquid chromatography to investigate the components and pharmacological properties of this classical herbal medicine in traditional Chinese medicine. Based on network pharmacology, we performed computational prediction simulation of the potential targets of JBT, which indicated the NF-kappa B pathway as its target, which was confirmed in vitro. JBT suppressed the production of pro-inflammatory cytokines including interleukin-6 (IL-6) and IL-8, and inhibited the expression of matrix metalloproteinase 1 in fibroblast-like synoviocytes derived from RA patients (MH7A cells). Furthermore, JBT also suppressed the phosphorylation of p38, JNK, and p65 in TNF-α-treated MH7A cells. In summary, this study proved that JBT could inhibit synovial inflammation and bone destruction, possibly by blocking the phosphorylation of NF-kappa B pathway-mediated production of proinflammatory effectors.

Cirsium japonicum var. maackii and apigenin block Hif-2α-induced osteoarthritic cartilage destruction

Although Hif-2α is a master regulator of catabolic factor expression in osteoarthritis development, Hif-2α inhibitors remain undeveloped. The aim of this study was to determine whether Cirsium japonicum var. maackii (CJM) extract and one of its constituents, apigenin, could attenuate the Hif-2α-induced cartilage destruction implicated in osteoarthritis progression. In vitro and in vivo studies demonstrated that CJM reduced the IL-1β-, IL-6, IL-17- and TNF-α-induced up-regulation of MMP3, MMP13, ADAMTS4, ADAMTS5 and COX-2 and blocked osteoarthritis development in a destabilization of the medial meniscus mouse model. Activation of Hif-2α, which directly up-regulates MMP3, MMP13, ADAMTS4, IL-6 and COX-2 expression, is inhibited by CJM extract. Although cirsimarin, cirsimaritin and apigenin are components of CJM and can reduce inflammation, only apigenin effectively reduced Hif-2α expression and inhibited Hif-2α-induced MMP3, MMP13, ADAMTS4, IL-6 and COX-2 expression in articular chondrocytes. IL-1β induction of JNK phosphorylation and IκB degradation, representing a critical pathway for Hif-2α expression, was completely blocked by apigenin in a concentration-dependent manner. Collectively, these effects indicate that CJM and one of its most potent constituents, apigenin, can lead to the development of therapeutic agents for blocking osteoarthritis development as novel Hif-2α inhibitors.

3'-Sialyllactose as an inhibitor of p65 phosphorylation ameliorates the progression of experimental rheumatoid arthritis

Background and Purpose

3′‐Sialyllactose (3′‐SL) is a safe compound that is present in high levels in human milk. Although it has anti‐inflammatory properties and supports immune homeostasis, its effect on collagen‐induced arthritis (CIA) is unknown. In this study, we investigated the prophylactic and therapeutic effect of 3′‐SL on the progression of rheumatoid arthritis (RA) in in vitro and in vivo models.

Experimental Approach

The anti‐arthritic effect of 3′‐SL was analysed with fibroblast‐like synoviocytes in vitro and an in vivo mouse model of CIA. RT‐PCR, Western blotting and ELISA were performed to evaluate its effects in vitro. Histological analysis of ankle and knee joints of mice with CIA was performed using immunohistochemistry, as well as safranin‐O and haematoxylin staining.

Key Results

3′‐SL markedly alleviated the severity of CIA in the mice by reducing paw swelling, clinical scores, incidence rate, serum levels of inflammatory cytokines and autoantibody production. Moreover, 3′‐SL reduced synovitis and pannus formation and suppressed cartilage destruction by blocking secretion of chemokines, pro‐inflammatory cytokines, https://en.wikipedia.org/wiki/Matrix_metalloproteinases and osteoclastogenesis via NF‐κB signalling. Notably, phosphorylation of p65, which is a key protein in the NF‐κB signalling pathway, was totally blocked by 3′‐SL in the RA models.

Conclusions and Implications

3′‐SL ameliorated pathogenesis of CIA by suppressing catabolic factor expression, proliferation of inflammatory immune cells and osteoclastogenesis. These effects were mediated via blockade of the NF‐κB signalling pathway. Therefore, 3′‐SL exerted prophylactic and therapeutic effects and could be a novel therapeutic agent for the treatment of RA.