miR-206-3p Targets Brain-Derived Neurotrophic Factor and Affects Postoperative Cognitive Function in Aged Mice.

Postoperative cognitive dysfunction (POCD) occurs after surgery and severely impairs patients' quality of life. Finding POCD-associated variables can aid in its diagnosis and prognostication. POCD is associated with noncoding RNAs, such as microRNAs (miRNAs), involved in metabolic function, immune response alteration, and cognitive ability impairment; however, the underlying mechanisms remain unclear. The aim of this study was to investigate hub miRNAs (i.e., miRNAs that have an important regulatory role in diseases) regulating postoperative cognitive function and the associated mechanisms. Hub miRNAs were identified by bioinformatics, and their expression in mouse hippocampus tissues was determined using real-time quantitative polymerase chain reaction. Hub miRNAs were overexpressed or knocked down in cell and animal models to test their effects on neuroinflammation and postoperative cognitive function. Six differentially expressed hub miRNAs were identified. miR-206-3p was the only broadly conserved miRNA, and it was used in follow-up studies and animal experiments. Its inhibitors reduced the release of proinflammatory cytokines in BV-2 microglia by regulating its target gene, brain-derived neurotrophic factor (BDNF), and the downstream signaling pathways. miR-206-3p inhibition suppressed microglial activation in the hippocampi of mice and improved learning and cognitive decline. Therefore, miR-206-3p significantly affects POCD, implying its potential as a therapeutic target.

Evaluation of genetic integrity of pearl millet seeds during aging by genomic-SSR markers.

Seed is an important way to store germplasm resources but its genetic integrity will decrease during long-term preservation. So, it's essential to update seeds according to the aging level of different species. Pearl millet [Cenchrus americanus (L.) Morrone syn., Pennisetum glaucum (L.) R. Br.] is a crucial forage grass, biofuel plant and important crops in the world bringing huge economic and ecological benefits. However, there is no report about the impact of aging on genetic integrity of its seeds. In this study, four genetic diversity indexes (the percentage of polymorphic bands, PPB; the effective number of alleles, Ne; the Nei's gene diversity index, H; the Shannon's information index, I) and 20 pairs of genomic-SSR primers were used to certify the optimal sample volume of pearl millet for molecular study and found that the best sample volume was 60. After the artificial aging test, the germination rate and four genetic diversity parameters (the number of alleles, Na; Ne; H; I) were used to evaluate the change of genetic integrity at different aging levels. The results showed that the germination rate and these four genetic diversity parameters declined with the increase of aging levels. Furthermore, when the germination rate of pearl millet seeds went down to 68.23%, a significant difference in genetic integrity was observed with unaged seeds. In conclusion, the optimal sample size of pearl millet was 60 and the critical point of germination rate to renew germplasm resources was 68.23% and these finds might contribute to the scientific study and the safe conservation of pearl millet.

Autopolyploidization in switchgrass alters phenotype and flowering time via epigenetic and transcription regulation.

Polyploidization is a significant source of genomic and organism diversification during plant evolution, and leads to substantial alterations in plant phenotypes and natural fitness. To help understand the phenotypic and molecular impacts of autopolyploidization, we conducted epigenetic and full-transcriptomic analyses of a synthesized autopolyploid accession of switchgrass (Panicum virgatum) in order to interpret the molecular and phenotypic changes. We found that mCHH levels were decreased in both genic and transposable element (TE) regions, and that TE methylation near genes was decreased as well. Among 142 differentially expressed genes involved in cell division, cellulose biosynthesis, auxin response, growth, and reproduction processes, 75 of them were modified by 122 differentially methylated regions, 10 miRNAs, and 15 siRNAs. In addition, up-regulated PvTOE1 and suppressed PvFT probably contribute to later flowering time of the autopolyploid. The expression changes were probably associated with modification of nearby methylation sites and siRNAs. We also experimentally demonstrated that expression levels of PvFT and PvTOE1 were regulated by DNA methylation, supporting the link between alterations in methylation induced by polyploidization and the phenotypic changes that were observed. Collectively, our results show epigenetic modifications in synthetic autopolyploid switchgrass for the first time, and support the hypothesis that polyploidization-induced methylation is an important cause of phenotypic alterations and is potentially important for plant evolution and improved fitness.

Combinations of Small RNA, RNA, and Degradome Sequencing Uncovers the Expression Pattern of microRNA⁻mRNA Pairs Adapting to Drought Stress in Leaf and Root of Dactylis glomerata L.

Drought stress is a global problem, and the lack of water is a key factor that leads to agricultural shortages. MicroRNAs play a crucial role in the plant drought stress response; however, the microRNAs and their targets involved in drought response have not been well elucidated. In the present study, we used Illumina platform (https://www.illumina.com/) and combined data from miRNA, RNA, and degradome sequencing to explore the drought- and organ-specific miRNAs in orchardgrass (Dactylis glomerata L.) leaf and root. We aimed to find potential miRNA⁻mRNA regulation patterns responding to drought conditions. In total, 519 (486 conserved and 33 novel) miRNAs were identified, of which, 41 miRNAs had significant differential expression among the comparisons (p < 0.05). We also identified 55,366 unigenes by RNA-Seq, where 12,535 unigenes were differently expressed. Finally, our degradome analysis revealed that 5950 transcripts were targeted by 487 miRNAs. A correlation analysis identified that miRNA ata-miR164c-3p and its target heat shock protein family A (HSP70) member 5 gene comp59407_c0 (BIPE3) may be essential in organ-specific plant drought stress response and/or adaptation in orchardgrass. Additionally, Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analyses found that "antigen processing and presentation" was the most enriched downregulated pathway in adaptation to drought conditions. Taken together, we explored the genes and miRNAs that may be involved in drought adaptation of orchardgrass and identified how they may be regulated. These results serve as a valuable genetic resource for future studies focusing on how plants adapted to drought conditions.

Hyperosmotic cold shock mouse melanoma cells encapsulated with doxorubicin for targeted treatment of melanoma.

Background: The primary treatment strategies for melanoma include surgical excision, chemotherapy, and radiotherapy. However, the efficacy of these treatments is often limited by drug resistance, recurrence, and severe side effects. Therefore, we aimed to develop a targeted drug delivery system capable of selectively locating tumor sites to minimize systemic toxicity and enhance therapeutic efficacy. This cell drug delivery system can also deliver chemotherapeutic drugs to the tumor microenvironment. Methods: We treated B16F10 cells with hyperosmotic cold shock (HCS) to obtain and characterize HCS cells. We then investigated the anti-tumor effects and immune activation capabilities of these cells and explored their potential as a targeted drug delivery system. Results: HCS cells not only maintained an intact cellular structure and tumor antigens but also exhibited high expression of the homologous melanoma-associated antigen glycoprotein 100. These cells demonstrated an exceptional capacity for loading and releasing doxorubicin, which has chemotherapeutic anti-tumor effects. HCS cells can precisely target the tumor microenvironment to minimize systemic toxicity, inducing an immune response by activating CD3+ and CD4+ T cells. Conclusion: HCS cells are non-carcinogenic, with both cellular and tumor antigens intact; thus, they are suitable drug delivery carriers. Our findings highlight the potential of HCS cells for carrying doxorubicin because of their high drug-loading efficiency, effective tumor-targeting and anti-tumor effects. Therefore, our results will facilitate the development of melanoma treatments that have higher efficacy than those in the literature.

siRNAs regulate DNA methylation and interfere with gene and lncRNA expression in the heterozygous polyploid switchgrass.

BACKGROUND: Understanding the DNA methylome and its relationship with non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), is essential for elucidating the molecular mechanisms underlying key biological processes in plants. Few studies have examined the functional roles of the DNA methylome in grass species with highly heterozygous polyploid genomes. RESULTS: We performed genome-wide DNA methylation profiling in the tetraploid switchgrass (Panicum virgatum L.) cultivar 'Alamo' using bisulfite sequencing. Single-base-resolution methylation patterns were observed in switchgrass leaf and root tissues, which allowed for characterization of the relationship between DNA methylation and mRNA, miRNA, and lncRNA populations. The results of this study revealed that siRNAs positively regulate DNA methylation of the mCHH sites surrounding genes, and that DNA methylation interferes with gene and lncRNA expression in switchgrass. Ninety-six genes covered by differentially methylated regions (DMRs) were annotated by GO analysis as being involved in stimulus-related processes. Functionally, 82% (79/96) of these genes were found to be hypomethylated in switchgrass root tissue. Sequencing analysis of lncRNAs identified two lncRNAs that are potential precursors of miRNAs, which are predicted to target genes that function in cellulose biosynthesis, stress regulation, and stem and root development. CONCLUSIONS: This study characterized the DNA methylome in switchgrass and elucidated its relevance to gene and non-coding RNAs. These results provide valuable genomic resources and references that will aid further epigenetic research in this important biofuel crop.

Genome-wide survey of switchgrass NACs family provides new insights into motif and structure arrangements and reveals stress-related and tissue-specific NACs.

NAC proteins comprise of a plant-specific transcription factor (TF) family and play important roles in plant development and stress responses. Switchgrass (Panicum virgatum) is the prime candidate and model bioenergy grass across the world. Excavating agronomically valuable genes is important for switchgrass molecular breeding. In this study, a total of 251 switchgrass NAC (PvNACs) family genes clustered into 19 subgroups were analyzed, and those potentially involved in stress response or tissue-specific expression patterns were pinpointed. Specifically, 27 PvNACs were considered as abiotic stress-related including four membrane-associated ones. Among 40 tissue-specific PvNACs expression patterns eight factors were identified that might be relevant for lignin biosynthesis and/or secondary cell wall formation. Conserved functional domains and motifs were also identified among the PvNACs and potential association between these motifs and their predicted functions were proposed, that might encourage experimental studies to use PvNACs as possible targets to improve biomass production and abiotic stress tolerance.