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Background: Osteosarcoma (OS) is one of the most common primary malignant bone tumors, primarily originating from mesenchymal tissue. It is notorious for its high invasiveness, high disability rate, high mortality rate, and poor prognosis. In most primary and metastatic malignant tumors, bone destruction can promote cancer progression, which is closely related to osteoclast activation and the imbalance between osteoblasts and osteoclasts. A large number of studies confirmed that osteoclasts are an important part of OS, which play an active role in destroying bone homeostasis and promoting the progress of OS. Therefore, we conducted a detailed study of osteoclasts at the single cell level, aiming to find new OS therapeutic targets to prevent tumor progression and local spread. Methods: We analyzed the single-cell sequencing data of OS patients and usedMonocle2, Cytotrace, and Slingshot software to analyze the pseudo-sequential trajectory during OS progression. CellChat was used to reveal the communication between cells. PySCENIC was used to identify active transcription factors in osteoclasts. Finally, we further demonstrated the results by RT-qPCR analysis, CCK-8 assay, wound healing assay, Transwell assay, etc. Results: Through the analysis of single-cell sequencing data in OS, we identified a highly specific subgroup, C2MKI67+ Osteoclast. The key signaling pathway APP and the top 1 transcription factor PPARG in this subgroup played essential roles in osteoclast proliferation and differentiation. Given the pivotal role of osteoclasts in OS progression, we speculated that these signaling pathways and transcription factors could emerge as novel therapeutic targets, offering innovative strategies for OS treatment. Conclusion: This study enhanced our understanding of OS and osteoclasts through scRNA-seq. Furthermore, we discovered that PPARG amplifies osteoclast activation and proliferation, resulting in excessive bone resorption and degradation of the bone matrix, thereby creating a favorable environment for tumor cell proliferation and growth. By innovatively targeting PPARG, it affected osteoclast proliferation and thus affected tumor progression; this work offered new insights and directions for the clinical treatment of OS patients. [ABSTRACT FROM AUTHOR]

Background: Neuronal intranuclear inclusion disease (NIID) is genetically linked to CGG repeat expansion in the 5'-untranslated region of the NOTCH2NLC gene, with nascent polyglycine-containing protein (uN2CpolyG) identified as a primary pathogenic factor. Emerging clinical evidence suggests that inflammation contributes to NIID pathogenesis, yet the underlying molecular mechanisms remain elusive. This study aimed to elucidate the molecular interaction between uN2CpolyG and the NF-κB-NLRP3 pathway. Methods: Single-cell RNA sequencing was conducted on the skin tissues of NIID patients to assess changes in the expression of genes involved in inflammatory pathways. Cell models (HEK-293T and U87-MG) transfected with CGG9/69/100 expansion vectors were used to investigate alterations in the NF-κB-NLRP3-autophagy pathway. Additionally, the therapeutic potential of NF-κB activators was evaluated in a Drosophila model with a CGG expansion knock-in. Results: Single-cell sequencing revealed a significant reduction in the expression of NFKBIA, encoding NF-κB inhibitor alpha (IkBa), which facilitates the nuclear translocation of p65, a key NF-κB component. uN2CpolyG directly interacted with and sequestered p65 in nuclear inclusions, leading to reduced phosphorylated p65 (p-p65) levels. This sequestration significantly downregulated the NF-κB-NLRP3 pathway, impairing autophagy, as indicated by decreased LC3II/LC3I ratios. Treatment of CGG100 cells with lipopolysaccharide (LPS) significantly increased p-p65, NLRP3, and LC3II/LC3I levels while reducing insoluble uN2CpolyG levels and intranuclear inclusions. In the Drosophila knock-in model, LPS significantly reduced the number of intranuclear inclusions and improved phenotypic manifestations. Conclusions: This study revealed that uN2CpolyG directly interacts with and sequesters p65, thereby inhibiting the NF-κB-NLRP3 pathway and impairing autophagy. This mechanism highlights a novel therapeutic target for NIID and provides potentially broader insights into similar mechanisms in other neurodegenerative diseases characterized by misfolded protein aggregates. [ABSTRACT FROM AUTHOR]

Purpose: Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, but the therapies are not satisfactory. This study aimed to find AMD specific features through the analysis of high-throughput sequencing. Methods: In this study, we integrated six projects containing single-cell RNA sequencing (scRNA-seq) data to perform a comprehensive analysis for AMD samples in the tissues of retina and retinal pigment epithelium/choroid, and in the positions of macula and periphery. Differentially expressed genes (DEGs) were analyzed and crucial signaling pathways were identified across cell types and between the macula and periphery. The intercellular signaling transduction among cell types were inferred by "CellChat" to build cell–cell communication network under normal and AMD conditions, and verified at the transcriptional level. The CD31+ endothelial cells were obtained to evaluate the enrichment of KEGG pathways in atrophic and neovascular AMD, and GSVA was adopted to discover differential metabolic signals in each AMD type. Results: Thirteen major cell types were identified in the integrated scRNA-seq data. Although no disease-specific cell type or differential cell proportion was found, DEGs and enriched pathways were shown in cell-type- and position-dependent manners. Severe impairment of endothelial cell-mediated cell interactions was found in the signaling transduction network of the macula, and compromised cell interactions were observed in the periphery. Furthermore, distinct signaling pathways and metabolic states were uncovered in atrophic and neovascular AMD. Striking reduction in energy metabolism, lipid metabolism, and oxidative stress was indicated in the atrophic AMD. Conclusion: Conclusively, we discover aberrant signals and metabolic pathways in AMD samples, providing insight into mechanisms and potential therapeutic targets for the AMD treatment. [ABSTRACT FROM AUTHOR]

The tumor immune microenvironment (TiME) of human central nervous system (CNS) tumors remains to be comprehensively deciphered. Here, we employed flow cytometry and RNA sequencing analysis for a deep data-driven dissection of a diverse TiME and to uncover noncanonical immune cell types in human CNS tumors by using seven tumors from five patients. Myeloid subsets comprised classical microglia, monocyte-derived macrophages, neutrophils, and two noncanonical myeloid subsets: CD3+ myeloids and CD19+ myeloids. T lymphocyte subsets included double-negative (CD4− CD8−) T cells (DNTs). Noncanonical myeloids and DNTs were explored on independent datasets, suggesting that our DNT phenotype represents γδ T cells. Noncanonical myeloids were validated using orthogonal methods across 73 patients from three independent datasets. While the proportions of classical myeloids agreed with reported malignancy type-associated TiMEs, unexpectedly high lymphocyte frequencies were detected in gliosarcoma, which also showed a unique expression pattern of immune-related genes. Our findings highlight the potential of data-driven approaches in resolving CNS TiME to reveal the mosaic of immune cell types constituting TiME, warranting the need for future studies on the nonclassical immune cell subsets. [ABSTRACT FROM AUTHOR]

Anti-Aß immunotherapy use to treat Alzheimer's disease is on the rise. While anti-Aß antibodies provide hope in targeting Aß plaques in the brain, there still remains a lack of understanding regarding the cellular responses to these antibodies in the brain. In this study, we sought to identify the acute effects of anti-Aß antibodies on immune responses. To determine cellular changes due to anti-Aß antibody exposure, we intracranially injected 14 mo APP male and female mice with anti-Aß IgG1 (6E10) or control IgG1 into the cortex. After 24 h or 3 d, we harvested the cortex and performed a glial cell-enriched preparation for single-cell sequencing. Cell types, proportions, and cell-to-cell signaling were evaluated between the two injection conditions and two acute timepoints. We identified 23 unique cell clusters including microglia, astrocytes, endothelial cells, neurons, oligos/OPCs, immune cells, and unknown. The anti-Aß antibody-injected cortices revealed more ligand-receptor (L-R) communications between cell types, as well as stronger communications at only 24 h. At 3 d, while there were more L-R communications for the anti-Aß antibody condition, the strength of these connections was stronger in the control IgG condition. We also found evidence of an initial and strong communication emphasis in microglia-to-nonparenchymal immune cells at 24 h, specifically in the TGFß signaling pathway. We identify several pathways that are specific to anti-Aß antibody exposure at acute timepoints. These data lay the groundwork for understanding the brain's unique response to anti-Aß antibodies. [ABSTRACT FROM AUTHOR]

Rotator cuff tendon injuries often lead to shoulder pain and dysfunction. Traditional treatments such as surgery and physical therapy can provide temporary relief, but it is difficult to achieve complete healing of the tendon, mainly because of the limited repair capacity of the tendon cells. Therefore, it is particularly urgent to explore new treatment methods. In vitro experiments were performed to explore the mechanism of differentiation of umbilical cord mesenchymal stem cells (UCMSCs) to tendon cells and to evaluate their potential in promoting rotator cuff injury repair. Growth factors such as CTGF, GDF-6, and GDF-7 were used to induce the differentiation of UCMSCs, and gene expression changes during the differentiation process were analyzed by single-cell sequencing. Hes1 overexpression and animal models were constructed to study its role in UCMSCs differentiation and rotator cuff injury repair. CTGF was the optimal factor for inducing the differentiation of UCMSCs into tendon cells. With increasing induction time, UCMSCs exhibited obvious tendon cell characteristics, such as changes in cell morphology and increased expression of tendon-specific proteins (MKX, SCX, and TNC). Single-cell sequencing analysis revealed key cellular subpopulations and signaling pathways during differentiation. Furthermore, overexpression of the Hes1 gene significantly promoted the differentiation of UCMSCs to tendon cells and showed its therapeutic effect in rotator cuff injury repair in an animal model. This study confirmed the potential of UCMSCs in tendon injury repair, especially the critical role of Hes1 in promoting UCMSCs differentiation and rotator cuff tendon-bone healing, which provides a theoretical basis and experimental rationale for the development of new cellular therapeutic strategies. [ABSTRACT FROM AUTHOR]

Background: Carotid atherosclerotic plaque is the primary cause of cardiovascular and cerebrovascular diseases. It is closely related to oxidative stress and immune inflammation. This bioinformatic study was conducted to identify key oxidative stress-related genes and key immune cell infiltration involved in the formation, progression, and stabilization of plaques and investigate the relationship between them. Results: We show that the up-regulation of oxidative stress-related genes such as IDH1 and CD36 in resident-like macrophages and foam macrophages play a key role in the formation and progression of carotid atherosclerotic plaques. Conclusions: We discuss the role of oxidative stress and immune inflammation in the formation, progression, and stabilization of plaques by combining predictive models with analysis of single-cell data. It introduced novel insights into the mechanisms underlying carotid atherosclerosis formation and plaque progression and may assist in identifying potential therapeutic targets for their treatment. [ABSTRACT FROM AUTHOR]

Shiga toxin (Stx)-induced hemolytic uremic syndrome (HUS) poses a life-threatening complication for which a definitive treatment remains elusive. To exert its cytotoxic effect on renal cells, Stx must be delivered from the infected intestines to the kidney. However, the mechanism underlying Stx delivery remains unclear. Here we pinpoint monocytes as the primary carriers responsible for transporting Stx2 to the renal region. Through single-cell sequencing analysis of Stx2-B-bound peripheral white blood cells sorted by flow cytometry, we observe that nearly all monocytes exhibit strong Stx2-B binding, whereas less than 10% of neutrophils are associated with Stx2-B, albeit with a lower affinity. Further examination of the single-cell dataset and cell binding assays suggest that monocytes likely bind to Stx2-B through the Toll-like receptor 4. Remarkably, Stx-laden monocytes demonstrate their ability to transport Stx2 to human renal glomerular endothelial cells (HRGEC), subsequently inducing apoptosis in HRGEC. In a mouse model of Stx1/2-positive EDL933 infection-induced HUS, the presence of Stx2-positive monocytes in peripheral blood and infiltrated kidney tissues was observed. Finally, depleting monocytes through the usage of a CD14 neutralizing antibody or blocking monocyte chemotaxis via inhibition of CCL2 notably mitigates kidney injury and dysfunction caused by lipopolysaccharide (LPS)/Stx2 treatment. Our findings unveil the pivotal role of monocytes in Stx delivery during STEC infection and offer a promising therapeutic approach for Stx-induced HUS. [ABSTRACT FROM AUTHOR]

Background: Patent foramen ovale (PFO) is a congenital defect between the atria, resulting in abnormal hemodynamics. We conducted a genome-wide association study (GWAS) to identify common genetic variants associated with PFO. Methods: We performed a whole genome sequencing in a discovery cohort of 3,227 unrelated Chinese participants screened for PFO via contrast transthoracic echocardiography (cTTE). Single-nucleotide polymorphisms (SNPs) associated with PFO were further validated by Sanger sequencing and subsequently were evaluated in a validation cohort. Expression quantitative trait loci (eQTL) analysis was conducted using the GTEx database. Single-cell sequencing analyses with pseudotime trajectory modeling were employed to evaluate their expression in human fetal hearts. Results: The case-control GWAS of discovery cohort ultimately included 517 cases and 517 demographically matched controls. Of the 7,040,407 variants assessed, we identified rs1227675732 (OR = 2.903; 95% CI, 1.961 to 4.297; p = 3.05 × 10−8), rs62206790 (OR = 2.780; 95% CI, 1.864 to 4.146; p = 2.02 × 10−7), rs879176184 (OR = 2.724; 95% CI, 1.822 to 4.073; p = 4.30 × 10−7) and rs13115019 (OR = 2.437; 95% CI, 1.702 to 3.488; p = 5.80 × 10−7) as high-risk variants for PFO, while rs57922961 (OR = 0.5081; 95% CI, 0.388 to 0.666; p = 6.82 × 10−7) was identified as protective variant. These variations were replicated in the validation cohort (111 cases and 152 controls). Single-cell sequencing showed that CNOT2 , KCNMB4 , MLLT10 , IGBP1 , and FRG1 were highly expressed with significant changes during heart development. Conclusion: The identification of susceptible loci for PFO might provide insights into the pathogenesis of PFO and contribute to understanding heart development. Clinical Trial Registration: https://www.chictr.org.cn/showproj.html?proj=40590, identifier ChiCTR1900024623. [ABSTRACT FROM AUTHOR]