Staphylococcus aureus induces mammary gland fibrosis through activating the TLR/NF-κB and TLR/AP-1 signaling pathways in mice

The effect of bta-miR-1296 on the proliferation and extracellular matrix synthesis of bovine mammary fibroblasts

Mammary fibrosis in dairy cows is a chronic condition caused by mastitis, and can lead to serious culling of dairy cows resulting in huge economic losses in the dairy industry. MicroRNAs (miRNAs) exert an important role in regulating mammary gland health in dairy cows. This study investigated whether exosomal miRNAs in mammary epithelial cells can regulate the proliferation of bovine mammary fibroblasts (BMFBs) in mastitis. Liposome transfection technology was used to construct a cellular model of the overexpression and inhibition of miRNAs. The STarMir software, dual luciferase reporter gene test, real-time quantitative PCR (qRT-PCR), a Cell Counting Kit-8 (CCK-8), and a Western Blot and plate clone formation test were used to investigate the mechanism by which bta-miR-1296 regulates the proliferation of BMFBs. Target gene prediction results revealed that glutamate-ammonia ligase was a direct target gene by which bta-miR-1296 regulates cell proliferation. It was found that bta-miR-1296 significantly inhibited the proliferation of BMFBs. After BMFBs were transfected with a bta-miR-1296 mimic, mRNA expression in the extracellular matrix (ECM), α-smooth muscle actin (α-SMA), collagen type I alpha 1 chain (COL1α1) and collagen type III alpha 1 chain (COL3α1), and various cell growth factors (basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor-BB (PDGF-BB), and transforming growth factor-β1 (TGF-β1)) were down-regulated, and the expressions of α-SMA, COL1α1, COL3α1, phospho-extracellular regulated protein kinases, phospho-protein kinase B, TGF-β1, and phospho-Smad family member3 proteins were inhibited. In conclusion, bta-miR-1296 can inhibit the proliferation of BMFBs and the synthesis of ECM in BMFBs, thus affecting the occurrence and development of mammary fibrosis in dairy cows and laying the foundation for further studies to clarify the regulatory mechanism of mammary fibrosis.

Development and challenges of antimicrobial peptide delivery strategies in bacterial therapy: A review

The escalating global prevalence of antimicrobial resistance poses a critical threat, prompting concerns about its impact on public health. This predicament is exacerbated by the acute shortage of novel antimicrobial agents, a scarcity attributed to the rapid surge in bacterial resistance. This review delves into the realm of antimicrobial peptides, a diverse class of compounds ubiquitously present in plants and animals across various natural organisms. Renowned for their intrinsic antibacterial activity, these peptides provide a promising avenue to tackle the intricate challenge of bacterial resistance. However, the clinical utility of peptide-based drugs is hindered by limited bioavailability and susceptibility to rapid degradation, constraining efforts to enhance the efficacy of bacterial infection treatments. The emergence of nanocarriers marks a transformative approach poised to revolutionize peptide delivery strategies. This review elucidates a promising framework involving nanocarriers within the realm of antimicrobial peptides. This paradigm enables meticulous and controlled peptide release at infection sites by detecting dynamic shifts in microenvironmental factors, including pH, ROS, GSH, and reactive enzymes. Furthermore, a glimpse into the future reveals the potential of targeted delivery mechanisms, harnessing inflammatory responses and intricate signaling pathways, including adenosine triphosphate, macrophage receptors, and pathogenic nucleic acid entities. This approach holds promise in fortifying immunity, thereby amplifying the potency of peptide-based treatments. In summary, this review spotlights peptide nanosystems as prospective solutions for combating bacterial infections. By bridging antimicrobial peptides with advanced nanomedicine, a new therapeutic era emerges, poised to confront the formidable challenge of antimicrobial resistance head-on.

Long-chain noncoding RNA sequencing analysis reveals the molecular profiles of chemically induced mammary epithelial cells

Long noncoding RNAs (lncRNAs) were important regulators affecting the cellular reprogramming process. Previous studies from our group have demonstrated that small molecule compounds can induce goat ear fibroblasts to reprogram into mammary epithelial cells with lactation function. In this study, we used lncRNA-Sequencing (lncRNA-seq) to analyze the lncRNA expression profile of cells before and after reprogramming (CK vs. 5i8 d). The results showed that a total of 3,970 candidate differential lncRNAs were detected, 1,170 annotated and 2,800 new lncRNAs. Compared to 0 d cells, 738 lncRNAs were significantly upregulated and 550 were significantly downregulated in 8 d cells. Heat maps of lncrnas and target genes with significant differences showed that the fate of cell lineages changed. Functional enrichment analysis revealed that these differently expressed (DE) lncRNAs target genes were mainly involved in signaling pathways related to reprogramming and mammary gland development, such as the Wnt signaling pathway, PI3K-Akt signaling pathway, arginine and proline metabolism, ECM-receptor interaction, and MAPK signaling pathway. The accuracy of sequencing was verified by real-time fluorescence quantification (RT-qPCR) of lncRNAs and key candidate genes, and it was also demonstrated that the phenotype and genes of the cells were changed. Therefore, this study offers a foundation for explaining the molecular mechanisms of lncRNAs in chemically induced mammary epithelial cells.

Microbiome dysbiosis occurred in hypertrophic scars is dominated by S. aureus colonization

Background

The mechanisms of hypertrophic scar formation and its tissue inflammation remain unknown.

Methods

We collected 33 hypertrophic scar (HS) and 36 normal skin (NS) tissues, and detected the tissue inflammation and bacteria using HE staining, Gram staining, and transmission electronic microscopy (TEM), in situ hybridization and immunohistochemistry for MCP-1, TNF-α, IL-6 and IL-8. In addition, the samples were assayed by 16S rRNA sequencing to investigate the microbiota diversity in HS, and the correlation between the microbiota and the indices of Vancouver Scar Scale(VSS)score.

Results

HE staining showed that a dramatically increased number of inflammatory cells accumulated in HS compared with NS, and an enhanced number of bacteria colonies was found in HS by Gram staining, even individual bacteria could be clearly observed by TEM. In situ hybridization demonstrated that the bacteria and inflammation cells co-localized in the HS tissues, and immunohistochemistry indicated the expression of MCP-1, TNF-α, IL-6, and IL-8 were significantly upregulated in HS than that in NS. In addition, there was a significantly different microbiota composition between HS and NS. At the phylum level, Firmicutes was significantly higher in HS than NS. At the genus level, S. aureus was the dominant species, which was significantly higher in HS than NS, and was strongly correlated with VSS indices.

Conclusion

Microbiome dysbiosis, dominated by S. aureus, occurred in HS formation, which is correlated with chronic inflammation and scar formation, targeting the microbiome dysbiosis is perhaps a supplementary way for future scar management.

N6-Methyladenosine Modification Profile in Bovine Mammary Epithelial Cells Treated with Heat-Inactivated Staphylococcus aureus

The symptoms of mastitis caused by Staphylococcus aureus (S. aureus) in dairy cows are not obvious and difficult to identify, resulting in major economic losses. N6-Methyladenosine (m6A) modification has been reported to be closely associated with the occurrence of many diseases. However, only a few reports have described the role of m6A modification in S. aureus-induced mastitis. In this study, after 24 h of treatment with inactivated S. aureus, MAC-T cells (an immortalized bovine mammary epithelial cell line) showed increased expression levels of the inflammatory factors IL-1β, IL-6, TNF-α, and reactive oxygen species. We found that the mRNA levels of METLL3, METLL14, WTAP, and ALKBH5 were also upregulated. Methylated RNA immunoprecipitation sequencing analysis revealed that 133 genes were m6A hypermethylated, and 711 genes were m6A hypomethylated. Biological functional analysis revealed that the differential m6A methylated genes were mainly related to oxidative stress, lipid metabolism, inflammatory response, and so on. In the present study, we also identified 62 genes with significant changes in m6A modification and mRNA expression levels. These findings elucidated the m6A modification spectrum induced by S. aureus in MAC-T cells and provide the basis for subsequent m6A research on mastitis.

Fallopian tubal infertility: the result of Chlamydia trachomatis-induced fallopian tubal fibrosis

Chlamydia trachomatis is one of the most common pathogens of sexually transmitted diseases, and its incidence in genital tract infections is now 4.7% in south China. Infertility is the end result of C. trachomatis-induced fallopian tubal fibrosis and is receiving intense attention from scientists worldwide. To reduce the incidence of infertility, it is important to understand the pathology-related changes of the genital tract where C. trachomatis infection is significant, especially the mechanism of fibrosis formation. During fibrosis development, the fallopian tube becomes sticky and occluded, which will eventually lead to tubal infertility. At present, the mechanism of fallopian tubal fibrosis induced by C. trachomatis infection is unclear. Our study attempted to summarize the possible mechanisms of fibrosis caused by C. trachomatis infection in the fallopian tube by reviewing published studies and further providing potential therapeutic targets to reduce the occurrence of infertility. This study also provides ideas for future research. Factors leading to fallopian tube fibrosis include inflammatory factors, miRNA, ECT, cHSP, and host factors. We hypothesized that C. trachomatis mediates the transcription and translation of EMT and ECM via upregulating TGF signaling pathway, which leads to the formation of fallopian tube fibrosis and ultimately to tubal infertility.