Background: Lung adenocarcinoma (LUAD) is a common type of lung cancer with a high risk of metastasis, but the exact molecular mechanisms of metastasis are not yet understood. Methods: This study acquired single-cell transcriptomics profiling of 11 distal normal lung tissues, 11 primary LUAD tissues, and 4 metastatic LUAD tissues from the GSE131907 dataset. The lung multicellular ecosystems were characterized at a single-cell resolution, and the potential mechanisms underlying angiogenesis and metastasis of LUAD were explored. Results: We constructed a global single-cell landscape of 93,610 cells from primary and metastatic LUAD and found that IGF2BP2 was specifically expressed both in a LUAD cell subpopulation (termed as LUAD_IGF2BP2), and an endothelial cell subpopulation (termed as En_IGF2BP2). The LUAD_IGF2BP2 subpopulation progressively formed and dominated the ecology of metastatic LUAD during metastatic evolution. IGF2BP2 was preferentially secreted by exosomes in the LUAD_IGF2BP2 subpopulation, which was absorbed by the En_IGF2BP2 subpopulation in the tumor microenvironment. Subsequently, IGF2BP2 improved the RNA stability of FLT4 through m⁶A modification, thereby activating the PI3K-Akt signaling pathway, and eventually promoting angiogenesis and metastasis. Analysis of clinical data showed that IGF2BP2 was linked with poor overall survival and relapse-free survival for LUAD patients. Conclusions: Overall, these findings provide a novel insight into the multicellular ecosystems of primary and metastatic LUAD, and demonstrate that a specific LUAD_IGF2BP2 subpopulation is a key orchestrator promoting angiogenesis and metastasis, with implications for the gene regulatory mechanisms of LUAD metastatic evolution, representing themselves as potential antiangiogenic targets.

Both environmental and genetic factors contribute to the etiology of autoimmune thyroid disease (AITD) including Graves' disease (GD) and Hashimoto's thyroiditis (HT). However, the exact pathogenesis and interactions that occur between environmental factors and genes remain unclear, and therapeutic targets require further investigation due to limited therapeutic options. To solve such problems, this study utilized single-cell transcriptome, whole transcriptome, full-length transcriptome (Oxford nanopore technology), and metabolome sequencing to examine thyroid lesion tissues from 2 HT patients and 2 GD patients as well as healthy thyroid tissue from 1 control subject. HT patients had increased ATF4-positive thyroid follicular epithelial (ThyFoEp) cells, which significantly increased endoplasmic reticulum stress. The enhanced sustained stress resulted in cell death mainly including apoptosis and necroptosis. The ATF4-based global gene regulatory network and experimental validation revealed that N⁶-methyladenosine (m⁶A) reader hnRNPC promoted the transcriptional activity, synthesis, and translation of ATF4 through mediating m⁶A modification of ATF4. Increased ATF4 expression initiated endoplasmic reticulum stress signaling, which when sustained, caused apoptosis and necroptosis in ThyFoEp cells, and mediated HT development. Targeting hnRNPC and ATF4 notably decreased ThyFoEp cell death, thus ameliorating disease progression. Collectively, this study reveals the mechanisms by which microenvironmental cells in HT and GD patients trigger and amplify the thyroid autoimmune cascade response. Furthermore, we identify new therapeutic targets for the treatment of autoimmune thyroid disease, hoping to provide a potential way for targeted therapy.

With the aging of the population, the incidence of osteoporosis (OP) is on the rise, but the ecology of immune cell subpopulations in OP is poorly understood. Therefore, identifying cell subpopulations involved in promoting the development of OP may facilitate the development of new treatments. Based on bioinformatics analysis, we constructed a single-cell landscape of the OP microenvironment and identified immune cell subpopulations in OP to further explore the role of different subpopulations in the abnormal bone microenvironment. Among macrophages (Mac), the Mac_OLR1 subpopulation has an M1-like phenotype and significantly activates cytokine and osteoclast differentiation pathways, interacting with osteoclasts via the HBEGF-CD9 axis. In neutrophils (Neut), the Neut_RSAD2 subpopulation significantly activated cytokine and osteoclast differentiation pathways and had a high neutrophil extracellular trap (NET) score, and H1FX was identified as its potential regulator. In effector memory T (Tem) cells, the Tem_CCL4 subpopulation significantly activated osteoclast differentiation and immune inflammation-related pathways and highly expressed proinflammatory molecules such as CCL4, CCL4L2, CCL5 and IFNG. In B cells, the abundance of the B_ACSM3 subpopulation was significantly increased in the OP group and the osteoclast differentiation pathway was significantly activated, and MYB was identified as its potential regulator. In summary, we identified several immune cell subpopulations that may be involved in promoting the formation of OP, further identified the transcription factors that regulate these subpopulations, and speculated that the development of OP may be accompanied by immune inflammatory responses mediated by these subpopulations. These findings provide candidate molecules and cells for future OP research and may help facilitate the development of new therapies.