Lipopolysaccharide (LPS) induced inflammatory changes to differentially expressed miRNAs of the host inflammatory response

Comprehensive transcriptional analysis of pig facial skin development

Background

Skin development is a complex process that is influenced by many factors. Pig skin is used as an ideal material for xenografts because it is more anatomically and physiologically similar to human skin. It has been shown that the skin development of different pig breeds is different, and some Chinese pig breeds have the characteristics of skin thickness and facial skin folds, but the specific regulatory mechanism of this skin development is not yet clear.

Methods

In this study, the facial skin of Chenghua sows in the four developmental stages of postnatal Day 3 (D3) , Day 90 (D90) , Day 180 (D180), and Year 3 (Y3) were used as experimental materials, and RNA sequencing (RNA-seq) analysis was used to explore the changes in RNA expression in skin development at the four developmental stages, determine the differentially expressed messenger RNAs (mRNAs), long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), and perform functional analysis of related genes by Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses.

Results

A pairwise comparison of the four developmental stages identified several differentially expressed genes (DEGs) and found that the number of differentially expressed RNAs (DE RNAs) increased with increasing developmental time intervals. Elastin (ELN) is an important component of the skin. Its content affects the relaxation of the epidermis and dermal connection, and its expression is continuously downregulated during the four developmental stages. The functions of DEGs at different developmental stages were examined by performing GO and KEGG analyses, and the GO terms and enrichment pathways of mRNAs, lncRNAs, miRNAs, and circRNAs highly overlapped, among which the PPAR signaling pathway, a classical pathway for skin development, was enriched by DEGs of D3 vs. D180, D90 vs. D180 and D180 vs. Y3. In addition, we constructed lncRNA-miRNA-mRNA and circRNA-miRNA interaction networks and found genes that may be associated with skin development, but their interactions need further study.

Conclusions

We identified a number of genes associated with skin development, performed functional analyses on some important DEGs and constructed interaction networks that facilitate further studies of skin development.

Effects of swine microRNA mimics on lipopolysaccharide (LPS) induced inflammatory changes in 3D4/21 cells

There have been limited studies focused on validation of swine microRNAs (miRNA) with mRNA targets. The objective of this study was to validate a defined set of targets using artificial miRNA mimics transfected into cell lines to confirm specific targets of endogenous miRNAs after administration of Escherichia coli lipopolysaccharide (LPS). Sixteen hours after mimic transfection of 3D4/21 cell lines, the cells were stimulated with 1 μg/ml LPS or phosphate-buffered saline (PBS). The cells were harvested and collected at 0, 1, 3, and 8 h post administration. The selected genes DAD1, IL8, and ESR, which are involved in known pathways of inflammation. and are predicted or validated human targets of either miR-146a, let-7a, or miR-22-3p. These were then evaluated by quantitative real-time-PCR (qRT-PCR) to verify microRNA-mRNA interaction in swine. Using the ROX reference dye, mRNA changes in expression were assessed using the comparative CT Method (ΔΔCT method) for normalization against the PBS control group. DAD1 and ESR1 were negatively regulated by miR-22-3p and miR-146a-5p, respectively in 3D4/21 cells after LPS stimulation. However, miR-146a-5p may play an indirect positive regulatory role of both DAD1 and IL8 mRNA expression. Furthermore, we found an inverse relationship between LPS stimulation compared with the let-7a-5p overexpression with DAD1. Our inflammation study provides new evidence on the roles and predicted targets of miR-146a, let-7a, and miR-22-3p in swine.