Microbial Co-Occurrence Patterns and Keystone Species in the Gut Microbial Community of Mice in Response to Stress and Chondroitin Sulfate Disaccharide

An injectable cartilage-coating composite with long-term protection, effective lubrication and chondrocyte nourishment for osteoarthritis treatment

The osteoarthritic (OA) environment within articular cartilage poses significant challenges, resulting in chondrocyte dysfunction and cartilage matrix degradation. While intra-articular injections of anti-inflammatory drugs, biomaterials, or bioactive agents have demonstrated some effectiveness, they primarily provide temporary relief from OA pain without arresting OA progression. This study presents an injectable cartilage-coating composite, comprising hyaluronic acid and decellularized cartilage matrix integrated with specific linker polymers. It enhances the material retention, protection, and lubrication on the cartilage surface, thereby providing an effective physical barrier against inflammatory factors and reducing the friction and shear force associated with OA joint movement. Moreover, the composite gradually releases nutrients, nourishing OA chondrocytes, aiding in the recovery of cellular function, promoting cartilage-specific matrix production, and mitigating OA progression in a rat model. Overall, this injectable cartilage-coating composite offers promising potential as an effective cell-free treatment for OA. STATEMENT OF SIGNIFICANCE: Osteoarthritis (OA) in the articular cartilage leads to chondrocyte dysfunction and cartilage matrix degradation. This study introduces an intra-articular injectable composite material (HDC), composed of decellularized cartilage matrix (dECMs), hyaluronan (HA), and specially designed linker polymers to provide an effective cell-free OA treatment. The linker polymers bind HA and dECMs to form an integrated HDC structure with an enhanced degradation rate, potentially reducing the need for frequent injections and associated trauma. They also enable HDC to specifically coat the cartilage surface, forming a protective and lubricating layer that enhances long-term retention, acts as a barrier against inflammatory factors, and reduces joint movement friction. Furthermore, HDC nourishes OA chondrocytes through gradual nutrient release, aiding cellular function recovery, promoting cartilage-specific matrix production, and mitigating OA progression.

Stochastic Processes Derive Gut Fungi Community Assembly of Plateau Pikas (Ochotona curzoniae) along Altitudinal Gradients across Warm and Cold Seasons

Although fungi occupy only a small proportion of the microbial community in the intestinal tract of mammals, they play important roles in host fat accumulation, nutrition metabolism, metabolic health, and immune development. Here, we investigated the dynamics and assembly of gut fungal communities in plateau pikas inhabiting six altitudinal gradients across warm and cold seasons. We found that the relative abundances of Podospora and Sporormiella significantly decreased with altitudinal gradients in the warm season, whereas the relative abundance of Sarocladium significantly increased. Alpha diversity significantly decreased with increasing altitudinal gradient in the warm and cold seasons. Distance-decay analysis showed that fungal community similarities were significantly and negatively correlated with elevation. The co-occurrence network complexity significantly decreased along the altitudinal gradients as the total number of nodes, number of edges, and degree of nodes significantly decreased. Both the null and neutral model analyses showed that stochastic or neutral processes dominated the gut fungal community assembly in both seasons and that ecological drift was the main ecological process explaining the variation in the gut fungal community across different plateau pikas. Homogeneous selection played a weak role in structuring gut fungal community assembly during the warm season. Collectively, these results expand our understanding of the distribution patterns of gut fungal communities and elucidate the mechanisms that maintain fungal diversity in the gut ecosystems of small mammals.

Di-n-butyl phthalate stress hampers compost multifunctionality by reducing microbial biomass, diversity and network complexity

Phthalates are common pollutants in agriculture. Here, the influence of di-n-butyl phthalate (DBP) on multifunctionality of composting was assessed. Results indicated that DBP stress (100 mg/kg) hampered multifunctionality from the thermophilic phase onwards and resulted in a 6.5 % reduction of all assessed functions. DBP stress also significantly reduced microbial biomass (P < 0.05), altered microbial composition (P < 0.05), and decreased network complexity (P < 0.01). Multifunctionality was found to be strongly correlated (P < 0.001) with microbial biomass, diversity, and network complexity. In addition, keystone taxa responsive to DBP were identified as Streptomyces, Thermoactinomyces, Mycothermus, and Lutispora. These taxa were significantly (P < 0.001) affected by DBP stress, and a correlation between them and multifunctionality was shown. This study contributes to a better understanding of the negative implications of phthalates during composting processes, which is of great significance to the development of new treatment strategies for agricultural waste.

Recent advances in developing butyrogenic functional foods to promote gut health

As one of the major short-chain fatty acids produced via microbial fermentation, butyrate serves as not only a preferred energy substrate but also an important signaling molecule. Butyrate concentrations in circulation, tissues, and gut luminal contents have important pathophysiological implications. The genetic capacity of butyrate biosynthesis by the gut microbiota is frequently compromised during aging and various disorders, such as inflammatory bowel disease, metabolic disorders and colorectal cancer. Substantial efforts have been made to identify potent butyrogenic substrates and butyrate-hyperproducing bacteria to compensate for butyrate deficiency. Interindividual butyrogenic responses exist, which are more strongly predicted by heterogeneity in the gut microbiota composition than by ingested prebiotic substrates. In this review, we catalog major food types rich in butyrogenic substrates. We also discuss the potential of butyrogenic foods with proven properties for promoting gut health and disease management using findings from clinical trials. Potential limitations and constraints in the current research are highlighted. We advocate a precise nutrition approach in designing future clinical trials by prescreening individuals for key gut microbial signatures when recruiting study volunteers. The information provided in this review will be conducive to the development of microbiota engineering approaches for enhancing the sustained production of butyrate.

Composite Sophora Colon-Soluble Capsule Ameliorates DSS-Induced Ulcerative Colitis in Mice via Gut Microbiota-Derived Butyric Acid and NCR+ ILC3

OBJECTIVE

To investigate the effects of composite Sophora colon-soluble Capsule (CSCC) on gut microbiota-mediated short-chain fatty acids (SCFAs) production and downstream group 3 innate lymphoid cells (ILC3s) of dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice model.

METHODS

The main components of CSCC were analyzed by hybrid ultra-high-performance liquid chromatography ion mobility spectromety quadrupole time-of-flight mass spectrometry (UHPLC-IM-QTOF/MS). Twenty-four male BALB/c mice were randomly divided into 4 groups (n=6) by using a computer algorithm-generated random digital, including control, DSS model, mesalazine, and CSCC groups. A DSS-induced colitis mice model was established to determine the effects of CSCC by recording colonic weight, colonic length, index of colonic weight, and histological colonic score. The variations in ILC3s were assessed by immunofluorescence and flow cytometry. The results of gut microbiota and SCFAs were acquired by 16s rDNA and gas chromatography-mass spectrometry (GC-MS) analysis. The expression levels of NCR⁺ ILC3^-, CCR6⁺ Nkp46^- (Lti) ILC3^-, and ILCreg-specific markers were detected by enzyme-linked immunosorbent assay, and real-time quantitative polymerase chain reaction and Western blot, respectively.

RESULTS

The main components of CSCC were matrine, ammothamnine, Sophora flavescens neoalcohol J, and Sophora oxytol U. After 7 days of treatment, CSCC significantly alleviated colitis by promoting the reproduction of intestinal probiotics manifested as upregulation of the abundance of Bacteroidetes species and specifically the Bacteroidales_S24-7 genus (P<0.05). Among the SCFAs, the content of butyric acid increased the most after CSCC treatment. Meanwhile, compared with the model group, Lti ILC3s and its biomarkers were significantly downregulated and NCR⁺ ILC3s were significantly elevated in the CSCC group (P<0.01). Further experiments revealed that ILC3s were differentiated from Lti ILC3s to NCR⁺ ILC3s, resulting in interleukin-22 production which regulates gut epithelial barrier function.

CONCLUSION

CSCC may exert a therapeutic effect on UC by improving the gut microbiota, promoting metabolite butyric acid production, and managing the ratio between NCR⁺ ILC3s and Lti ILC3s.

Self-Assembling Peptide Dendron Nanoparticles with High Stability and a Multimodal Antimicrobial Mechanism of Action

Self-assembling nanometer-scale structured peptide polymers and peptide dendrimers have shown promise in biomedical applications due to their versatile properties and easy availability. Herein, self-assembling peptide dendron nanoparticles (SPDNs) with potent antimicrobial activity against a range of bacteria were developed based on the nanoscale self-assembly of an arginine-proline repeat branched peptide dendron bearing a hexadecanoic acid chain. The SPDNs are biocompatible, and our most active peptide dendron nanoparticle, C₁₆-3RP, was found to have negligible toxicity after both in vitro and in vivo studies. Furthermore, the C₁₆-3RP nanoparticles showed excellent stability under physiological concentrations of salt ions and against serum and protease degradation, resulting in highly effective treatment in a mouse acute peritonitis model. Comprehensive analyses using a series of biofluorescence, microscopy, and transcriptome sequencing techniques revealed that C₁₆-3RP nanoparticles kill Gram-negative bacteria by increasing bacterial membrane permeability, inducing cytoplasmic membrane depolarization and drastic membrane disruption, inhibiting ribosome biogenesis, and influencing energy generation and other processes. Collectively, C₁₆-3RP nanoparticles show promising biocompatibility and in vivo therapeutic efficacy without apparent resistance development. These advancements may facilitate the development of peptide-based antibiotics in clinical settings.

Effect of the skincare product on facial skin microbial structure and biophysical parameters: A pilot study

Daily use of cosmetics is known to affect the skin microbiome. This study aimed to determine the bacterial community structure and skin biophysical parameters following the daily application of a skincare product on the face. Twenty-five Korean women, who used the same skincare product for four weeks participated in the study. During this period, skin hydration, texture, sebum content, and pH were measured, and skin swab samples were collected on the cheeks. The microbiota was analyzed using the MiSeq system. Through these experiments, bacterial diversity in facial skin increased and the microbial community changed after four weeks of skincare product application. The relative abundance of Cutibacterium and Staphylococcus increased, significant changes in specific bacterial modules of the skin microbial network were observed, and skin hydration and texture improved. It was suggested that daily use of skincare products could affect the microbial structure of facial skin as well as the biophysical properties of the facial skin. These findings expand our understanding of the role of skincare products on the skin environment.

Microbial Composition and Co-occurrence Patterns in the Gut Microbial Community of Normal and Obese Mice in Response to Astaxanthin

The changes and interaction of gut microbiota, which respond to dietary supplements, play critical roles on improving human health. The modulating effect of astaxanthin on gut microbiota has been reported. However, little is known about the co-occurrence patterns among microbial taxa in response to astaxanthin. In this study, the gut microbial composition, co-occurrence patterns, and microbial correlations with physiological parameters in astaxanthin-fed normal and obese mice were studied. Astaxanthin altered the microbial composition and co-occurrence patterns in normal and obese mice. Furthermore, astaxanthin gave more profound impacts on microbiota in obesity when compared with normal mice. In group A (normal or obese mice supplemented with astaxanthin), the abundance of Acinetobacter was decreased, and Alistipes was increased by astaxanthin, which also occurred in the MA group (obese mice supplemented with astaxanthin). An operational taxonomic unit (OTU) (GreenGeneID# 4029632) assigned to the genus Bacteroides acted as a connector in the global network of A and MA groups. It may play critical roles in bridging intimate interactions between the host and other bacteria intervened by astaxanthin. Several modules correlated with physiological parameters were detected. For example, modules A12 and MA10 were significantly and negatively correlated with lipopolysaccharide (LPS) and fasting blood glucose (FBG) levels, respectively. A positive correlation was found between the node connectivity of the OTUs belonging to Clostridiaceae with LPS in obese mice, which indicated the role of Clostridiales as a potential pathological marker. Our findings provided a new interpretation of the role of astaxanthin in health and may contribute to further research on microbial community engineering.

919 Syrup Alleviates Postpartum Depression by Modulating the Structure and Metabolism of Gut Microbes and Affecting the Function of the Hippocampal GABA/Glutamate System

Postpartum depression (PPD) is a mental disorder that affects pregnant women around the world, with serious consequences for mothers, families, and children. Its pathogenesis remains unclear, and medications for treating PPD that can be used during lactation remain to be identified. 919 syrup (919 TJ) is a Chinese herbal medicine that has been shown to be beneficial in the treatment of postpartum depression in both clinical and experimental studies. The mechanism of action of 919 TJ is unclear. 919 syrup is ingested orally, making the potential interaction between the drug and the gut microbiome impossible to ignore. We therefore hypothesized that 919 syrup could improve the symptoms of postpartum depression by affecting the structure and function of the intestinal flora, thereby altering hippocampal metabolism. We compared changes in hippocampal metabolism, fecal metabolism, and intestinal microflora of control BALB/c mice, mice with induced untreated PPD, and mice with induced PPD treated with 919 TJ, and found that 4-aminobutyric acid (GABA) in the hippocampus corresponded with PPD behaviors. Based on changes in GABA levels, multiple key gut bacterial species (Mucispirillum schaedleri, Bifidobacterium pseudolongum, Desulfovibrio piger, Alloprevotella tannerae, Bacteroides sp.2.1.33B and Prevotella sp. CAG:755) were associated with PPD. Metabolic markers that may represent the function of the intestinal microbiota in mice with PPD were identified (Met-Arg, urocanic acid, thioetheramide-PC, L-pipecolic acid, and linoleoyl ethanolamide). The relationship between these factors is not a simple one-to-one correspondence, but more likely a network of staggered functions. We therefore believe that the composition and function of the entire intestinal flora should be emphasized in research studying the gut and PPD, rather than changes in the abundance of individual bacterial species. The introduction of this concept of “GutBalance” may help clarify the relationship between gut bacteria and systemic disease.

Next Generation Microbiome Research: Identification of Keystone Species in the Metabolic Regulation of Host-Gut Microbiota Interplay

The community of the diverse microorganisms residing in the gastrointestinal tract, known as the gut microbiota, is exceedingly being studied for its impact on health and disease. This community plays a major role in nutrient metabolism, maintenance of the intestinal epithelial barrier but also in local and systemic immunomodulation. A dysbiosis of the gut microbiota, characterized by an unbalanced microbial ecology, often leads to a loss of essential functions that may be associated with proinflammatory conditions. Specifically, some key microbes that are depleted in dysbiotic ecosystems, called keystone species, carry unique functions that are essential for the balance of the microbiota. In this review, we discuss current understanding of reported keystone species and their proposed functions in health. We also elaborate on current and future bioinformatics tools needed to identify missing functions in the gut carried by keystone species. We propose that the identification of such keystone species functions is a major step for the understanding of microbiome dynamics in disease and toward the development of microbiome-based therapeutics.