Molecular mechanism of radiation tolerance in lung adenocarcinoma cells using single-cell RNA sequencing.

The efficacy of radiotherapy, a cornerstone in the treatment of lung adenocarcinoma (LUAD), is profoundly undermined by radiotolerance. This resistance not only poses a significant clinical challenge but also compromises patient survival rates. Therefore, it is important to explore this mechanism for the treatment of LUAD. Multiple public databases were used for single-cell RNA sequencing (scRNA-seq) data. We filtered, normalized and downscaled scRNA-seq data based on the Seurat package to obtain different cell subpopulations. Subsequently, the ssGSEA algorithm was used to assess the enrichment scores of the different cell subpopulations, and thus screen the cell subpopulations that are most relevant to radiotherapy tolerance based on the Pearson method. Finally, pseudotime analysis was performed, and a preliminary exploration of gene mutations in different cell subpopulations was performed. We identified HIST1H1D+ A549 and PIF1+ A549 as the cell subpopulations related to radiotolerance. The expression levels of cell cycle-related genes and pathway enrichment scores of these two cell subpopulations increased gradually with the extension of radiation treatment time. Finally, we found that the proportion of TP53 mutations in patients who had received radiotherapy was significantly higher than that in patients who had not received radiotherapy. We identified two cellular subpopulations associated with radiotherapy tolerance, which may shed light on the molecular mechanisms of radiotherapy tolerance in LUAD and provide new clinical perspectives.

Dicalcium silicate microparticles modulate the differential expression of circRNAs and mRNAs in BMSCs and promote osteogenesis via circ_1983-miR-6931-Gas7 interaction.

Dicalcium silicate microparticle (C2S)-based biomaterials have a potential for bone and dental tissue regenerative applications. The C2S-mediated transcriptome level mechanism in mesenchymal stem cells (MSCs) during bone-defect healing has not been investigated yet. In this study, we elucidated the differential expression pattern of messenger RNAs (mRNAs) and circular RNAs (circRNAs) in C2S-treated MSCs and their involvement in the osteogenesis process. C2S robustly enhanced the osteogenic differentiation of MSCs and cranial bone defect healing. C2S-treatment modulated the differential expression of mRNAs and circRNAs in MSCs. Differentially expressed circRNAs and mRNAs were involved in competing endogenous RNA (ceRNA-interaction networks). These ceRNA-interaction networks regulated the signaling pathways associated with osteogenesis, e.g., Wnt, PI3K-Akt, MAPK, and JAK/STAT signaling. C2S-treatment upregulated the expression of circ_1983, Gas7, and Runx2 in BMSCs. RNase R and luciferase activity assay confirmed the stability and miR-6931 sponging property of circ_1983, respectively. Knockdown of circ_1983 enhanced miR-6931 expression but inhibited Gas7 and Runx2 expression and osteogenic differentiation in C2S-treated MSCs. In conclusion, for the first time, we report the role of cicr_1983-miR-6931-Gas7 ceRNA-interaction in C2S-induced osteogenic differentiation of MSCs and bone defect healing. This study opens a new research stream "the role of circRNAs-mediated ceRNA-interaction in biomaterials and stem cell-based bone tissue engineering".

Synthesis and application of a dual chiral [2.2]paracyclophane-based N-heterocyclic carbene in enantioselective ß-boration of acyclic enones.

An enantioselective conjugate addition of boron to α,ß-unsaturated ketones catalysed by either a N-heterocyclic carbene or a copper-carbene complex generated in situ from a new chiral bicyclic triazolium based on [2.2]paracyclophane is presented. The dual chiral carbene-copper catalyst has significant advantages over its carbene counterpart as an organocatalyst in asymmetric ß-boration of acyclic enones, giving a variety of chiral ß-boryl ketones in good yields and enantioselectivities. This is a successful example of employing the same N-heterocyclic carbene in one catalytic reaction as both an organocatalyst and a ligand for transition metal catalysis.

Application of Bidentate Oxazoline-Carbene Ligands with Planar and Central Chirality in Asymmetric ß-Boration of α,ß-Unsaturated Esters.

A series of new oxazoline-substituted imidazolium salts based on [2.2]paracyclophane were synthesized and characterized. The new bidentate oxazoline-carbene precursor with planar and central chirality had significant advantage than the bicyclic 1,2,4-triazolium salt derived from [2.2]paracyclophane as a monodentate carbene ligand in Cu(I)-catalyzed asymmetric ß-boration of α,ß-unsaturated esters, giving the desired products in high enantioselectivities and yields.