Background: Major depressive disorder (MDD) is an emotional condition that interferes with sufferers’ work and daily life. Numerous studies have found that miRNAs play a significant role in the development of MDD and can be utilized as a biomarker for its diagnosis and therapy. However, there have been few studies on nerve-immunity interaction treatment for the brains of MMD patients. Methods: The work is performed on microarray data. We analyzed the differences of miRNAs (GSE58105, GSE81152, GSE152267, and GSE182194) and mRNA (GSE19738, GSE32280, GSE44593, GSE53987, and GSE98793) in MDD and healthy samples from GEO datasets. FunRich was used to predict the transcription factors and target genes of the miRNAs, and TF and GO enrichment analyses were performed. Then, by comparing the differential expression of the anticipated target genes and five mRNAs, intersecting mRNAs were discovered. The intersecting genes were submitted to GO and KEGG analyses to determine their functions. These intersecting potential genes and pathways that linked to MDD in neurological and immunological aspects have been identified for future investigation. Results: We discovered five hub genes: KCND2, MYT1L, GJA1, CHL1, and SNAP25, which were all up-regulated genes. However, in MMD, the equivalent miRNAs, hsa-miR-206 and hsa-miR-338-3p, were both down-regulated. These miRNAs can activate or inhibit the T cell receptor signal pathway, JAK-STAT and other signal pathways, govern immune-inflammatory response, neuronal remodeling, and mediate the onset and development of MMD Conclusions: The results of a thorough bioinformatics investigation of miRNAs and mRNAs in MDD showed that miR-338-3P and miR-206 might be effective biomarkers and possible therapeutic targets for the treatment of MDD via nerve-immunity interaction.

Dandelion (Taraxacum officinale) is widely consumed as a health food and a traditional medicine. However, the protective effect of dandelion bio‐active peptides (DPs) against polycyclic aromatic hydrocarbon‐induced blood vessel inflammation and oxidative damage is not well documented. In the current study, four novel DPs were isolated using an activity tracking method. The protective activity of the DPs against benzo(a)pyrene (Bap)‐induced human umbilical vein endothelial cell (HUVEC) damage was explored. The results indicated that DP‐2 [cycle‐(Thr‐His‐Ala‐Trp)] effectively inhibited Bap‐induced reactive oxygen species (ROS) and malondialdehyde (MDA) overproduction and reinforced antioxidant enzyme activity while inhibiting the production of inflammatory factors in HUVECs. Moreover, DP‐2 increased NAD(P)H:quinone oxidoreductase 1, heme oxygenase‐1, and nuclear factor E2‐releated factor 2 expression levels by activating the PI3K/Akt signaling pathway. In addition, DP‐2 attenuated Bap‐induced HUVEC apoptosis via the Bcl‐2/Bax/cytochrome c apoptotic pathway. These results suggest that DP‐2 is a promising compound for protecting HUVECs from Bap‐induced inflammatory and oxidative damage.