Intrahepatic cholangiocarcinoma (ICC) is the second most common liver malignancy. ICC typically features a remarkably cellular heterogeneity and dense stromal reaction. Therefore, a comprehensive understanding of cellular diversity and the interplay between malignant cells and niche cells is essential for elucidating the mechanisms driving ICC progression and developing therapeutic approaches. Herein, we performed single-cell RNA sequencing (scRNA-seq) analysis on unselected viable cells from eight human ICC and adjacent samples to elucidate the comprehensive transcriptomic landscape and intercellular communication network. Additionally, we applied a negative selection strategy to enrich fibroblast populations in two other ICC samples to investigate fibroblast diversity. The results of the analyses were validated using multiplex immunofluorescence staining, bulk transcriptomic datasets, and functional in vitro and in vivo experiments. We sequenced a total of 56,871 single cells derived from human ICC and adjacent tissues and identified diverse tumor, immune, and stromal cells. Malignant cells displayed a high degree of inter-tumor heterogeneity. Moreover, tumor-infiltrating CD4 regulatory T cells (Tregs) exhibited highly immunosuppressive characteristics. We identified six distinct fibroblast subsets, of which the majority were CD146 positive vascular cancer-associated fibroblasts (vCAFs), with highly expressed microvasculature signatures and high levels of IL-6. Functional assays indicated that IL-6 secreted by vCAFs induced significant epigenetic alterations in ICC cells, particularly upregulating enhancer of zeste homolog 2 (EZH2) and thereby enhancing malignancy. Furthermore, ICC cell-derived exosomal miR-9-5p elicited a high expression of IL-6 in vCAFs to promote tumor progression. Our study provides a transcriptomic landscape of human ICC at single-cell resolution and intercellular crosstalk between ICC cells and vCAFs, suggesting potential therapeutic targets.

Cervical squamous cell carcinoma (CESC) is a prototypical human cancer with well-characterized pathological stages of initiation and progression. However, high-resolution knowledge of the transcriptional programs underlying each stage of CESC is lacking, and important questions remain. We performed single-cell RNA sequencing of 76,911 individual cells from 13 samples of human cervical tissues at various stages of malignancy, illuminating the transcriptional tumorigenic trajectory of cervical epithelial cells and revealing key factors involved in CESC initiation and progression. In addition, we found significant correlations between the abundance of specific myeloid, lymphoid, and endothelial cell populations and the progression of CESC, which were also associated with patients’ prognosis. Last, we demonstrated the tumor-promoting function of matrix cancer–associated fibroblasts via the NRG1-ERBB3 pathway in CESC. This study provides a valuable resource and deeper insights into CESC initiation and progression, which is helpful in refining CESC diagnosis and for the design of optimal treatment strategies.

Tertiary lymphoid structures (TLSs) have emerged as critical prognostic and immunotherapeutic indicators in cancer, with their clinical significance modulated by spatial distribution patterns and density. Here, we performed integrated single-cell and spatial transcriptomic profiling of 30 gastric cancer (GC) specimens stratified by TLS spatial localization patterns. Comparative analysis shows pronounced enrichment of CXCL13⁺ T lymphocytes (TLCs), CXCR5⁺ germinal center B lymphocytes (gc_B cells), LAMP3⁺CD80⁺ activated dendritic cells (DCs), and SELP⁺ACKR1⁺ high endothelial venule (HEV) cells within intratumoral-TLS (iTLS) rich tumors compared to peritumoral-TLS (pTLS) and desert-TLS (dTLS) tumor subtypes. Multimodal cell-cell interaction analysis and functional experiments demonstrate that HEV expressed VCAM1 and ICAM1 recruits and activates CXCL13⁺ TLC through the CXCL13-ACKR1 pathway, which promotes TLS formation via CXCL13-CXCR5-dependent crosstalk with B lymphocytes. We further develop a single-cell/spatial TLS signature that captures the cellular ecosystem of iTLS-containing tumor, demonstrating predictive value for immunotherapy outcomes in GC patients.

Despite significant advancements in identifying novel therapeutic targets and compounds, cancer stem cells (CSCs) remain pivotal in driving therapeutic resistance and tumor progression in gastric cancer (GC). High‐resolution knowledge of the transcriptional programs underlying the role of CSC niche in driving tumor stemness and progression is still lacking. Herein, spatial and single‐cell RNA sequencing of 32 human gastric mucosa tissues at various stages of malignancy, illuminating the phenotypic plasticity of tumor epithelium and transcriptional trajectory from mature gastric chief cells to the CSC state, which is associated with activation of EGFR and WNT signaling pathways, is conducted. Moreover, the CSCs interact with not only the immunosuppressive CXCL13⁺ T cells and CCL18⁺ M2 macrophages to evade immune surveillance, but also the inflammatory cancer‐associated fibroblasts (iCAFs) to promote tumorigenesis and maintain stemness, which construct the CSC niche leading to inferior prognosis. Notably, it is uncovered that amphiregulin (AREG) derived from iCAFs promotes tumor stemness by upregulating the expression of SOX9 in tumor cells, and contributes to drug resistance via the AREG‐ERBB2 axis. This study provides valuable insight into the characteristics of CSC niche in driving tumor stemness and progression, offering novel perspective for designing effective strategies to overcome GC therapy resistance.

Checkpoint inhibitor pneumonitis (CIP) is the most common fatal immune-related adverse event; however, its pathophysiology remains largely unknown. Comprehensively dissecting the key cellular players and molecular pathways associated with CIP pathobiology is critical for precision diagnosis and develop novel therapy strategy of CIP. Herein, we performed a comprehensive single-cell transcriptome analysis to dissect the complexity of the immunological response in the bronchoalveolar lavage fluid (BALF) microenvironment. CIP was characterized by a dramatic accumulation of CXCL13+ T cells and hyperinflammatory CXCL9+ monocytes. T-cell receptor (TCR) analysis revealed that CXCL13+ T cells exhibited hyperexpanded- TCR clonotypes, and pseudotime analysis revealed a potential differentiation trajectory from naïve to cytotoxic effector status. Monocyte trajectories showed that LAMP3+ DCs derived from CXCL9+ monocytes possessed the potential to migrate from tumors to the BALF, whereas the differentiation trajectory to anti-inflammatory macrophages was blocked. Intercellular crosstalk analysis revealed the signaling pathways such as CXCL9/10/11-CXCR3, FASLG-FAS, and IFNGR1/2-IFNG were activated in CIP+ samples. We also proposed a novel immune signature with high diagnostic power to distinguish CIP+ from CIP− samples (AUC = 0.755). Our data highlighted key cellular players, signatures, and interactions involved in CIP pathogenesis.

Dry eye disease (DED) is a prevalent inflammatory condition significantly impacting quality of life, yet lacks effective pharmacological therapies. Herein, we proposed a novel approach to modulate the inflammation through metabolic remodeling, thus promoting dry eye recovery. Our study demonstrated that co-treatment with mesenchymal stem cells (MSCs) and thymosin beta-4 (Tβ4) yielded the best therapeutic outcome against dry eye, surpassing monotherapy outcomes. In situ metabolomics through matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) revealed increased glutamine levels in cornea following MSC + Tβ4 combined therapy. Inhibition of glutamine reversed the anti-inflammatory, anti-apoptotic, and homeostasis-preserving effects observed with combined therapy, highlighting the critical role of glutamine in dry eye therapy. Clinical cases and rodent model showed elevated expression of glutaminase (GLS1), an upstream enzyme in glutamine metabolism, following dry eye injury. Mechanistic studies indicated that overexpression and inhibition of GLS1 counteracted and enhanced, respectively, the anti-inflammatory effects of combined therapy, underscoring GLS1’s pivotal role in regulating glutamine metabolism. Furthermore, single-cell sequencing revealed a distinct subset of pro-inflammatory and pro-fibrotic corneal epithelial cells in the dry eye model, while glutamine treatment downregulated those subclusters, thereby reducing their inflammatory cytokine secretion. In summary, glutamine effectively ameliorated inflammation and the occurrence of apoptosis by downregulating the pro-inflammatory and pro-fibrotic corneal epithelial cells subclusters and the related IκBα/NF-κB signaling. The present study suggests that glutamine metabolism plays a critical, previously unrecognized role in DED and proposes an attractive strategy to enhance glutamine metabolism by inhibiting the enzyme GLS1 and thus alleviating inflammation-driven DED progression.