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Follicular Lymphoma Transformation is Characterized by Cytokine-associated Remodeling of Stromal and Macrophage Compartments.

Across cancer, one of the most frequent examples of histologic transformation is the evolution of follicular lymphoma (FL) to an aggressive large cell lymphoma. Despite recent progress, understanding of the molecular and cellular underpinnings of transformation remains incomplete. Here, we dissect the interplay of tumor and microenvironment cell populations across transformation through a multimodal investigation of 95 FL and transformed FL (tFL) samples, including single-cell and bulk RNA-sequencing alongside spatial transcriptomics and proteomics, and validate findings across independent FL-tFL pairs. Upon transformation, fibroblasts and GPNMB+ macrophages increase while lymph-node organizing follicular dendritic and CCL21+ fibroblastic reticular cells were lost, resulting in an altered spatial distribution of cytokines that impacts T cell infiltration and macrophage differentiation and function. Secreted stromal and macrophage signals were further evident by non-invasive plasma proteomics. Taken together, our data reveal expansion of macrophages and fibroblasts as key features of transformation with potential diagnostic and therapeutic implications.

Journal Article↗

T-Cell Leukemia Cell Line Harboring Previously Undescribed CBFB::MYL11 Fusion Exhibits a Genome Profile Implicating Cytoskeletal Abnormality.

INTRODUCTION: Gene fusions involving core binding factors (CBFs), such as CBFB::MYH11, are major contributing factors to leukemia development. The pathogenic mechanism is believed to lie in abnormalities in CBF, however, myosin, the fusion partner, has received little attention. In a preliminary analysis, we identified a previously undescribed fusion transcript, CBFB::MYL11, in RNA-sequencing data from the T-cell leukemia cell line HPB-ALL. We hypothesized that leukemia cells harboring CBFB::MYH11 or CBFB::MYL11 may share a common pathological mechanism involving myosin fusion. METHODS: Fluorescence in situ hybridization was performed to analyze the structure of CBFB::MYL11 and Western blotting was performed to verify the fusion protein in HPB-ALL. Differentially expressed gene (DEG) and gene ontology (GO) analyses were performed on ME-1 harboring CBFB::MYH11 and HPB-ALL to investigate characteristics of gene expression and molecular function. RESULTS: In situ amplification of MYL11 and co-amplification of CBFB and MYL11 on a marker chromosome were observed. Elevated MYH11 and MYL11 expression and significant upregulation of genes related to the cytoskeleton were observed in the ME-1 and HPB-ALL cell lines. Bands consistent with the CBFB::MYL11 fusion protein were observed using Western blotting. CONCLUSION: This study underscores the pathological significance of cytoskeletal abnormalities in leukemia with CBFB/myosin fusion and provides a foundation for further investigation into their molecular mechanisms.

Journal Article↗

An integrated single-cell and spatial transcriptomic atlas of thyroid cancer progression identifies prognostic fibroblast subpopulations.

Although well-differentiated thyroid carcinoma (WDTC) is characterized by a robust treatment response, aggressive subtypes, such as anaplastic thyroid carcinoma (ATC), remain highly lethal. To understand thyroid cancer evolution in both children and adults, we analyzed single-cell transcriptomes of 423,733 cells from 81 samples and spatially resolved key tumor and microenvironment populations across 28 tumors with spatial transcriptomics, including rare and unique composite WDTC/ATC tumors and pediatric diffuse sclerosing thyroid carcinomas. Additionally, we identified gene signatures of stromal cell populations in 5 large thyroid cancer bulk RNA-sequencing cohorts. Through this multi-institutional effort, we defined a population of POSTN+ myofibroblast cancer-associated fibroblasts (myCAFs) that are intimately associated with invasive tumor cells and correlate with poor prognosis, lymph node metastasis, and disease progression in thyroid carcinoma. We also revealed a population of inflammatory CAFs that are distant to tumor cells and are found in the inflammatory stromal microenvironment of autoimmune thyroiditis. Together, our study provides spatial profiling of thyroid cancer evolution in samples with mixed WDTC/ATC histopathology and identifies a prognostic myCAF subtype with potential clinical utility in predicting aggressive disease in both children and adults.

Humans↗

BET inhibition blunts antibody production and macrophage-mediated fibrosis to restore lung function in murine cGVHD.

Chronic graft-versus-host disease (cGVHD) significantly contributes to late mortality after allogeneic stem cell transplantation, with bronchiolitis obliterans syndrome (BOS) being a particularly lethal and treatment-resistant complication despite available therapies. Bromodomain and extraterminal (BET) proteins are epigenetic readers driving inflammatory transcriptional programs across multiple cell types. We hypothesized that BET inhibition would suppress inflammatory T and B cells and decrease macrophage polarization to a profibrotic phenotype, alleviating disease. In an established BOS cGVHD model, BET inhibition reduced germinal center (GC) formation and responses through a reduction of the CXCL13:CXCR5 axis and inflammatory T follicular helper/GC B cells in the spleen, along with a reduction in plasma cell infiltration within the lung. Mice with cGVHD had elevated pathogenic immunoglobulin G1 (IgG1) and IgM levels, both in circulation and deposited on lung tissue, which were attenuated under BET inhibition. Single-cell RNA-sequencing analysis revealed distinct cell states in the BOS lung vs control. In cGVHD mice, gene set enrichment analysis revealed the upregulation of profibrotic Arginase1 and Tgfb1 expression in alveolar macrophages (AM) and interstitial macrophages (IM), which was significantly reduced with BET inhibition. Furthermore, BET inhibition targeted lung-infiltrating M2 macrophages through the selective depletion of CD206+FcγR+ IM and AM, ultimately resulting in reduced collagen deposition and improved lung function. Our findings reveal a previously unrecognized mechanistic axis of BET regulation during cGVHD fibrosis and highlight BET inhibition as a promising therapeutic strategy.

Animals↗

The N6-methyladenosine reader IGF2BP2 in T-cell lymphoma.

Peripheral T-cell lymphoma (PTCL) represents a highly heterogeneous and aggressive lymphoid neoplasm that lacks pathogenic biomarkers of RNA modification with therapeutic potential. IGF2BP2 is recognized as an N6-methyladenosine reader critically involved in oncogenesis. In this study, we observed consistently high expression of IGF2BP2 across common nodal PTCL subtypes in 3 independent external cohorts, which was further confirmed in our RNA-sequencing (RNA-seq) data set of 196 patients with newly diagnosed PTCL. Both in vitro and in vivo, IGF2BP2 promoted tumor cell growth and inhibited CD8+ T-cell infiltration within the tumor microenvironment. Mechanistically, IGF2BP2 bound to endosome-related genes (RAB4, VPS35, RAB9, and STAM) to maintain their stability, which resulted in enhanced endocytic activity and increased internalization of membrane proteins, and ultimately induced tumor cell proliferation and inhibition of CD8+ T-cell-mediated tumor cytotoxicity. The relationship between IGF2BP2 and endocytosis-associated genes was confirmed using RNA-seq data from patients with PTCL. IGF2BP2 as an upstream regulator of both tumor growth and immune suppression was further demonstrated in patient-derived xenograft models and a coculture system established using tumor samples from patients with PTCL and peripheral blood mononuclear cells. Notably, therapeutic targeting of IGF2BP2 with CWI1-2 suppressed endocytosis and impeded tumor growth in both cell lines and patient-derived xenograft models. Collectively, our findings highlight IGF2BP2 as a clinically relevant oncogenic driver in PTCL that integrates tumor-intrinsic growth signals with immune evasion through endocytosis-centered regulation, providing a novel therapeutic rationale for RNA modification-based strategies that concurrently target tumor cells and the tumor microenvironment.

Humans↗

Blood-derived gene expression profiles associated with dietary microalgae oil intake and methane emission variation in lambs.

BACKGROUND: Minimising methane (CH4) emissions from livestock production is a global priority, and feed modifications, such as supplementing diets with microalgae, have previously been shown to help reducing enteric CH4 production. This study explored blood-derived host gene expression profiles from twenty lambs supplemented with increasing levels of microalgae oil to investigate their transcriptional responses associated with varying microalgae oil levels while also exploring the host systemic responses towards varied CH4 productions. RESULTS: Findings revealed no significant changes in CH4 production with increasing levels of microalgae oil intake through phenotypic analysis (P = 0.18). However inter-individual variations in CH4 production ranged from 27.02 to 47.86 g/day throughout the study period. Blood RNA-Sequencing identified 64 significant genes including DHCR7, DHCR24, HMGCS1, INSIG1, LSS, MSMO1, and SQLE, which were involved in lipid metabolism, and steroid biosynthesis that became enriched alongside increasing microalgae oil intake levels thereby contributing to a positive impact on lambs' metabolic functions. Additionally, seven significant blood-expressed host genes (NME4, MARCHF3, PLXNB3, LOC132657460, LOC121819234, LOC105603087, LOC101116551) functionally enriched in nucleotide metabolic pathways and immune responses were identified to have significant positive associations with increasing CH4 production. Importantly, this study found no overlap between genes associated with microalgae oil intake and those linked to CH4 emissions. CONCLUSIONS: Findings suggest that microalgae oil intake and inter-individual variations in CH₄ production are associated with distinct blood-derived transcriptional responses. Although such signals should be interpreted as proxies for systemic host responses rather than direct measures of rumen-specific processes, these results emphasise the importance of considering host-associated molecular variations alongside dietary CH₄-mitigation strategies.

Animals↗

Construction of an immunogenic cell death-related LncRNA signature to predict the prognosis of patients with lung adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LUAD) is one of the most common malignant diseases worldwide. This study aimed to construct an immunogenic cell death (ICD)-related long non-coding RNA (lncRNA) signature to effectively predict the prognosis of LUAD. METHODS: The RNA-sequencing and clinical data of LUAD were downloaded from The Cancer Genome Atlas (TCGA). Least absolute shrinkage and selection operator (LASSO) and stepwise multivariate Cox proportional hazard regression analysis were utilized to construct lncRNA signature. Then, the reliability of the signature was evaluated in the training, validation and whole cohorts. The differences in the immune landscape and drug sensitivity between the low- and high-risk groups were analyzed. Finally, the expression level of the selected ICD-related lncRNAs in LUAD cell lines via reverse transcription quantitative PCR (RT-qPCR). CCK-8 and transwell assays were performed to study biological function of AC245014.3. RESULTS: A signature consisting of 5 ICD-related lncRNAs was constructed. Kaplan Meier (K-M) survival analysis showed shorter overall survival (OS) in high-risk group. The receiver operating characteristic (ROC) curves and Multivariate Cox regression analysis showed the signature was good predictive and independent prognostic factor in LUAD. Moreover, the high-risk group had a lower level of antitumor immunity and was less sensitive to some chemotherapeutics and targeted drugs. Finally, the expression level of selected ICD-related lncRNAs was validated in LUAD cell lines by RT-qPCR. Knockdown of AC245014.3 significantly suppressed LUAD proliferation, migration and invasion. CONCLUSIONS: In this study, an ICD-related lncRNA signature was constructed, which could accurately predict the prognosis of LUAD patients and guide clinical treatment.

Humans↗

Genetics-Informed Mapping Identifies a CRIM1-Associated Endocardial Inflammatory Remodeling State in Acute Myocardial Infarction.

BACKGROUND Acute myocardial infarction (AMI) reflects inherited susceptibility and inflammatory remodeling, but the cellular contexts linking genetic risk to disease remain unclear. MATERIAL AND METHODS We integrated a meta-transcriptome-wide association study (TWAS) with a human cardiac single-nucleus RNA-sequencing atlas contained 11 individuals (5 AMI and 6 donor) to identify genetics-informed cellular programs. Composite program states were defined by global score quartiles. A fixed 5-gene panel was evaluated for nucleus-level endocardial low-transcriptional-state (Endo_LTS) vs endocardial high-transcriptional-state (Endo_HTS) discrimination within the AMI endocardium using 5-fold leave-1-patient-out cross-validation. Functional follow-up used CRIM1 silencing in hypoxia-treated human induced pluripotent stem cell (hiPSC)-derived endocardial endothelial-like cells and complementary peripheral blood analyses. RESULTS The endocardium exhibited the most prominent infarction-associated increase in TWAS-anchored program activity, with expansion of program-high states and higher CytoTRACE scores. A consensus 5-gene panel (RPS8, PLEC, CFDP1, CRIM1, TNS2) was identified. Among 2163 AMI endocardial nuclei from 5 patients, the state classifier included 364 Endo_LTS and 751 Endo_HTS nuclei; 1048 Endo_MTS nuclei were excluded. Pooled out-of-fold ROC-AUCs ranged from 0.665 to 0.831. The panel also showed discriminatory value in an independent peripheral-blood AMI-vs-control cohort. CRIM1 was prioritized as a candidate linked to the remodeling program. CRIM1 silencing attenuated ACTA2/alpha-SMA, vimentin, LDHA, CCL2, and VEGFA and partially restored CD31, whereas TGF-ß remained elevated. CONCLUSIONS These findings identify a genetics-informed endocardial inflammatory remodeling state in AMI and define a 5-gene surrogate of its activated state. CRIM1 is prioritized as a candidate linked to selected inflammatory, metabolic, and structural outputs. Persistent TGF-b elevation after CRIM1 silencing argues against a simple linear regulatory model and indicates that further mechanistic validation is required.

Humans↗

Activated NAD+ biosynthesis pathway induces olaparib resistance in BRCA1 knockout pancreatic cancer cells.

PARP inhibitors have been developed as anti-cancer agents based on synthetic lethality in homologous recombination deficient cancer cells. However, resistance to PARP inhibitors such as olaparib remains a problem in clinical use, and the mechanisms of resistance are not fully understood. To investigate mechanisms of PARP inhibitor resistance, we established a BRCA1 knockout clone derived from the pancreatic cancer MIA PaCa-2 cells, which we termed C1 cells, and subsequently isolated an olaparib-resistant C1/OLA cells. We then performed RNA-sequencing and pathway analysis on olaparib-treated C1 and C1/OLA cells. Our results revealed activation of cell signaling pathway related to NAD+ metabolism in the olaparib-resistant C1/OLA cells, with increased expression of genes encoding the NAD+ biosynthetic enzymes NAMPT and NMNAT2. Moreover, intracellular NAD+ levels were significantly higher in C1/OLA cells than in the non-olaparib-resistant C1 cells. Upregulation of intracellular NAD+ levels by the addition of nicotinamide also induced resistance to olaparib and talazoparib in C1 cells. Taken together, our findings suggest that upregulation of intracellular NAD+ is one of the factors underlying the acquisition of PARP inhibitor resistance.

Humans↗

Repression of CADM1 transcription by HPV type 18 is mediated by three-dimensional rearrangement of promoter-enhancer interactions.

Upon infection, human papillomavirus (HPV) manipulates host cell gene expression to create an environment that is supportive of a productive and persistent infection. The virus-induced changes to the host cell's transcriptome are thought to contribute to carcinogenesis. Here, we show by RNA-sequencing that oncogenic HPV18 episome replication in primary human foreskin keratinocytes (HFKs) drives host transcriptional changes that are consistent between multiple HFK donors. We have previously shown that HPV18 recruits the host protein CTCF to viral episomes to control the differentiation-dependent viral transcriptional programme. Since CTCF is an important regulator of host cell transcription via coordination of epigenetic boundaries and long-range chromosomal interactions, we hypothesised that HPV18 may also manipulate CTCF to contribute to host transcription reprogramming. Analysis of CTCF binding in the host cell genome by ChIP-Seq revealed that while the total number of CTCF binding sites is not altered by the virus, there are a sub-set of CTCF binding sites that are either enriched or depleted of CTCF. Many of these altered sites are clustered within regulatory elements of differentially expressed genes, including the tumour suppressor gene cell adhesion molecule 1 (CADM1), which supresses epithelial cell growth and invasion. We show that HPV18 establishment results in reduced CTCF binding at the CADM1 promoter and upstream enhancer. Loss of CTCF binding is coincident with epigenetic repression of CADM1, in the absence of CpG hypermethylation, while adjacent genes including the transcriptional regulator ZBTB16 are activated. These data indicate that the CADM1 locus is subject to topological rearrangement following HPV18 establishment. We tested this hypothesis using 4C-Seq (circular chromosome confirmation capture-sequencing) and show that HPV18 establishment causes a loss of long-range chromosomal interactions between the CADM1 transcriptional start site and the upstream transcriptional enhancer. These data show that HPV18 manipulates host cell promoter-enhancer interactions to drive transcriptional reprogramming that may contribute to HPV-induced disease progression.

Humans↗

Construction and validation of a β-hydroxybutyrylation-related molecular model for predicting prognosis of papillary thyroid carcinoma.

BACKGROUND: Papillary thyroid carcinoma (PTC) usually has a favorable prognosis, yet a subset of patients develops persistent, recurrent, or biologically aggressive disease. The clinical relevance of lysine β-hydroxybutyrylation (Kbhb)-related transcriptional programs in PTC remains unclear. Accordingly, this study aimed to characterize Kbhb-related molecular heterogeneity in PTC, construct a prognostic signature, and explore its association with the tumor microenvironment (TME). METHODS: Transcriptomic and clinical data from PTC samples within The Cancer Genome Atlas Thyroid Carcinoma (TCGA-THCA) cohort were analyzed to identify Kbhb-related differentially expressed genes (DEGs), define molecular subtypes, construct a prognostic signature, and characterize tumor microenvironmental features. Single-cell RNA-sequencing data from PTC were further used to explore the cellular distribution of representative genes. RESULTS: We identified 51 Kbhb-related DEGs in PTC and defined two Kbhb molecular subtypes. The Kbhb_C2 subtype showed shorter progression-free interval (PFI) and a more immune- and stroma-enriched microenvironment. A six-gene prognostic signature comprising TARID, CDSN, PIMREG, KLRC1, SYT13, and NPR3 was then established. High-risk patients had significantly worse PFI in the full, training, and testing cohorts, with 1-, 3-, and 5-year areas under the curve (AUCs) of 0.715, 0.793, and 0.771, respectively, in the full cohort. High-risk tumors also exhibited higher stromal, immune, and ESTIMATE scores, altered immune infiltration, and increased expression of multiple immune checkpoint molecules. Single-cell analysis confirmed distinct cell-type-specific expression patterns of representative genes. CONCLUSIONS: Kbhb-related transcriptional programs define clinically relevant molecular heterogeneity in PTC and are closely associated with prognosis and TME remodeling. The identified six-gene signature provides a biologically interpretable framework for risk stratification in PTC.

Papillary thyroid carcinoma (PTC)↗

Matrine Alleviates Sepsis-Induced Acute Lung Injury by Reinforcing NQO1/SLC7A11/GPX4-Associated Anti-Ferroptotic Defenses and Attenuating NF-κB-Driven Inflammation.

BACKGROUND: Sepsis triggers dysregulated systemic inflammation and multiple-organ dysfunction, with the lungs being particularly susceptible to injury. Sepsis-induced acute respiratory distress syndrome (ARDS) is mainly driven by TLR4/NF-κB-mediated hyperinflammation and alveolar macrophage activation. Matrine, a bioactive alkaloid derived from Sophora flavescens, has been reported to modulate redox homeostasis and ferroptosis-associated lipid peroxidation. However, the target-specific mechanisms underlying its effects on ferroptosis and inflammatory signaling in sepsis-induced acute lung injury (SALI) remain incompletely understood. PURPOSE: This study aimed to evaluate the therapeutic effects of matrine in a cecal ligation and puncture (CLP)-induced SALI model and to determine whether its protective effects involve reinforcement of NQO1/SLC7A11/GPX4-associated anti-ferroptotic defenses and suppression of NF-κB-driven inflammation. METHODS: We analyzed the single-cell RNA-sequencing (scRNA-seq) dataset GSE273924 to characterize CD45-enriched pulmonary immune-cell subsets in sham mice and mice with intratracheal Escherichia coli-induced pneumonia. Network pharmacology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to predict Kushen (KS)-related targets and pathways associated with SALI. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) of GSE245013 were used to identify candidate targets. Matrine-NQO1 binding and intracellular target engagement were evaluated using molecular docking, molecular dynamics simulations, surface plasmon resonance (SPR), and the cellular thermal shift assay (CETSA). The therapeutic effects of matrine were assessed in mice with CLP-induced SALI and in lipopolysaccharide (LPS)-stimulated MH-S cells. Lung histopathology, inflammatory cytokine production, target protein expression, ferroptosis-associated indicators, and NF-κB activation were evaluated using molecular, biochemical, and histological assays. The functional contribution of NQO1 was further examined using the NQO1 inhibitor ES936. RESULTS: scRNA-seq analysis of GSE273924 revealed substantial remodeling of the CD45-enriched pulmonary immune-cell landscape in mice with intratracheal E. coli-induced pneumonia, including macrophage transcriptional programs associated with ferroptosis and inflammatory signaling. Integrated network pharmacology and bioinformatics analyses prioritized NQO1 as a candidate target of matrine and identified NF-κB signaling as a potentially relevant pathway. Molecular docking, molecular dynamics simulations, SPR, and CETSA supported matrine-NQO1 binding and intracellular target engagement. Functionally, matrine improved survival, attenuated lung injury, reinforced NQO1/SLC7A11/GPX4-associated anti-ferroptotic defenses, and suppressed NF-κB activation in CLP mice. Similar protective effects were observed in LPS-stimulated MH-S cells. ES936 partially attenuated the matrine-mediated improvements in cell viability, redox homeostasis, ferroptosis-associated indicators, and NF-κB p65 phosphorylation, supporting a functional contribution of NQO1 to the protective effects of matrine. CONCLUSION: Matrine alleviates SALI by reinforcing NQO1/SLC7A11/GPX4-associated anti-ferroptotic defenses and attenuating NF-κB-driven inflammation.

Animals↗

Human periodontal ligament stem cells promote oral ulcer healing in rats through modulation of TGF-β1/smad signaling.

BACKGROUND: Oral ulcers (OU) often present with prolonged healing, recurrent episodes, and scar formation, posing challenges for clinical management. Human periodontal ligament stem cells (hPDLSCs) have shown potential in oral tissue repair, but further research is needed to clarify their mechanism of action in OU healing. This study aims to elucidate the molecular mechanisms by which hPDLSCs promote oral ulcer healing. METHOD: To identify key regulatory genes, the OU-associated microarray dataset GSE37265 was integrated with hPDLSC genomic data for differential expression analysis. Subsequently, Weighted Gene Co-expression Network Analysis (WGCNA) was used to identify functional modules associated with OU healing. In vivo, hPDLSCs were locally administered into a rat ulcer model, and therapeutic efficacy was assessed by ulcer closure rates and histological evaluation (HE and Masson's trichrome staining). Furthermore, RNA-sequencing (RNA-seq) was performed on oral mucosal tissues to delineate the underlying molecular landscape and critical signaling pathways. The involvement of the TGF-β signaling pathway was confirmed by real-time quantitative PCR (RT-qPCR) and Western blotting (WB) analyses. RESULTS: Bioinformatics analysis identified 92 key genes in hPDLSCs-mediated treatment of OU, highlighting the central role of the TGF-β1/Smad pathway. As shown by the animal studies, hPDLSCs therapy increased the healing rate to 97% by day 8 (vs. 70% in the model). Furthermore, the therapy significantly reduced inflammatory cell infiltration and abnormal collagen deposition while promoting regular collagen arrangement. Transcriptomic and molecular experiments further showed that hPDLSCs simultaneously inhibit TGF-β1/Smad and extracellular signal-regulated kinase (ERK) signaling pathways, thereby alleviating inflammatory responses and suppressing mucosal fibrosis. CONCLUSION: In this study, we reveal a novel role for hPDLSCs in promoting oral ulcer healing. The findings indicate that hPDLSCs suppress inflammation and fibrosis via the TGF-β1/Smad pathway, offering a promising therapeutic strategy for OU and other fibrotic conditions.

TGF-β1↗

Complement expression profiles in human glomerular mesangial cells, endothelial cells, podocytes and proximal tubular epithelial cells.

BACKGROUND: Local expression of complement components in the kidney has been reported sporadically in both diseased and normal kidneys. This study aimed to comprehensively characterize the expression of complement components in human glomerular mesangial cells (GMCs), glomerular endothelial cells (GECs), podocytes, and proximal tubular epithelial cells (PTECs) in non-diseased renal tissue. METHODS: Complement expression in cultured human renal intrinsic cells was initially evaluated using reverse transcription polymerase chain reaction and immunofluorescence staining. These findings were further examined using publicly available single-cell RNA-sequencing datasets and 10×Genomics single-cell RNA sequencing of non-diseased human kidney tissue. The analyses focused on complement components involved in the initiation of the classical, lectin, and alternative pathways, as well as components shared among these activation pathways, terminal pathway components, complement regulators, and complement receptors. RESULTS: Complement components unique to the initial phase for classical pathway (C1S, C1R, C2, C4), lectin pathway (MBL2, FCN1, MASP1), alternative pathway (CFB, CFD), and the C3 component shared by the three activation pathways were detected in these cells. The components shared by the terminal pathways including C5, C6, C7, C8 and C9 exhibited lower expression, while complement regulators (CFH, CFI, CD55/DAF, CD46/MCP, CD59, C4BPB, PROS1/Protein S) or receptors (CD93/C1QR1, CR1), particularly membrane-bound proteins, such as DAF, MCP and CD59, which inhibit complement activation and the formation of the membrane attack complex, showed relatively high expression. CONCLUSION: These results showed that all four types of intrinsic renal cells expressed multiple complement components associated with the classical, lectin, and alternative pathways. In non-diseased kidney tissue, complement regulatory molecules involved in the control of complement activation showed relatively higher expression, whereas components of the terminal complement pathway were expressed at relatively lower levels, suggesting that renal intrinsic cells maintain a locally poised but tightly regulated complement system.

Humans↗

Developing a disease-specific accessible transcriptional signature as a biomarker for ataxia with oculomotor apraxia type 2.

BACKGROUND: Genetic ataxias are clinically heterogenous neurodegenerative conditions often involving rare or private mutations and it is often difficult to assign pathogenicity to rare gene variants solely based on DNA sequencing. An effective functional assay from an easy-to-obtain biospecimen would aid this assessment and be of high clinical value. SETX encodes a ubiquitous DNA/RNA helicase crucial for resolving R-loops and maintaining genome stability. Loss-of-function mutations cause a recessive disorder, Ataxia with Oculomotor Apraxia Type 2 (AOA2). METHODS: Here we utilize Weighted Gene Co-expression Network Analysis (WGCNA) from patient blood to construct an AOA2-specific transcriptomic signature as a biomarker to evaluate SETX variants in patients clinically suspected of having AOA2. RESULTS: WGCNA from peripheral blood RNA of 11 AOA2 patients from 7 families initially identified a single gene module that was modestly effective in distinguishing individuals with AOA2 from controls (sensitivity 73%, specificity 97%) and was able to robustly differentiate AOA2 patients from those with genetically distinct, yet phenotypically similar, neurological disorders (sensitivity 100%, specificity 100%). An independent derivation of the transcriptional biomarker identified a dual module model that was able to better distinguish individuals with AOA2 from controls (sensitivity 100%, specificity 97%). As validation, we examined a second cohort of 21 patients from 13 families and demonstrate that this dual module transcriptional biomarker could discriminate patients clinically suspected of AOA2 from controls (57%, 95%CI: 34%-78%). Overall, the transcriptional biomarker was able to separate AOA2 subjects (n = 32) from controls (n = 35) with 72% sensitivity and 97% specificity. Notably, this transcriptomic biomarker enabled verification of the first pathogenic SETX mutation found in a non-canonical transcript, expanding the spectrum of mutations that contribute to AOA2. CONCLUSIONS: Our study identified a transcriptional biomarker that was able to differentiate AOA2 from controls and from other related neurological disorders, consequently expanding the spectrum of known pathogenic mutations. This proof-of-concept study illustrates that transcriptional biomarkers may be used to validate variants of uncertain significance in known genetic diseases.

Humans↗

ASXL1 truncating variants in BOS and myeloid leukemia drive shared disruption of Wnt-signaling pathways but have differential isoform usage of RUNX3.

BACKGROUND: Rare variants in epigenes (a.k.a. chromatin modifiers), a class of genes that control epigenetic regulation, are commonly identified in both pediatric neurodevelopmental syndromes and as somatic variants in cancer. However, little is known about the extent of the shared disruption of signaling pathways by the same epigene across different diseases. To address this, we study an epigene, Additional Sex Combs-like 1 (ASXL1), where truncating heterozygous variants cause Bohring-Opitz syndrome (BOS, OMIM #605039), a germline neurodevelopmental disorder, while somatic variants are driver events in acute myeloid leukemia (AML). No BOS patients have been reported to have AML. METHODS: This study explores common pathways dysregulated by ASXL1 variants in patients with BOS and AML. We analyzed whole blood transcriptomic and DNA methylation data from patients with BOS and AML with ASXL1-variant (AML-ASXL1) and examined differential exon usage and cell proportions. RESULTS: Our analyses identified common molecular signatures between BOS and AML-ASXL1 and highlighted key biomarkers, including VANGL2, GRIK5 and GREM2, that are dysregulated across samples with ASXL1 variants, regardless of disease type. Notably, our data revealed significant de-repression of posterior homeobox A (HOXA) genes and upregulation of Wnt-signaling and hematopoietic regulator HOXB4. While we discovered many shared epigenetic and transcriptomic features, we also identified differential splice isoforms in RUNX3 where the long isoform, p46, is preferentially expressed in BOS, while the shorter p44 isoform is expressed in AML-ASXL1. CONCLUSION: Our findings highlight the strong effects of ASXL1 variants that supersede cell-type and even disease states. This is the first direct comparison of transcriptomic and methylation profiles driven by pathogenic variants in a chromatin modifier gene in distinct diseases. Similar to RASopathies, in which pathogenic variants in many genes lead to overlapping phenotypes that can be treated by inhibiting a common pathway, our data identifies common pathways for ASXL1 variants that can be targeted for both disease states. Comparative approaches of high-penetrance genetic variants across cell types and disease states can identify targetable pathways to treat multiple diseases. Finally, our work highlights the connections of epigenes, such as ASXL1, to an underlying stem-cell state in both early development and in malignancy.

Humans↗

Malignant epithelial states drive immune dysfunction in ampulla of Vater carcinoma.

BACKGROUND: Ampulla of Vater (AoV) carcinoma is a rare malignancy arising at the junction of intestinal and pancreatobiliary epithelium. Its heterogeneous clinical behavior and histological diversity have hindered therapeutic advances, and the cellular basis of this heterogeneity remains unclear. We aimed to construct a single-cell transcriptomic atlas of AoV carcinoma, with a focus on identifying epithelial subtypes and their interactions with the tumor microenvironment (TME). METHODS: We performed single-cell RNA sequencing on eight primary AoV tumors and four matched normal tissues. Comprehensive clustering and transcriptomic analyses identified cell-type composition, epithelial heterogeneity, and tumor-immune interactions. Findings were validated using deconvolution of bulk RNA-seq data from 62 AoV carcinoma patients. Results Malignant epithelial cells were categorized into four distinct subtypes: Int-Wnt, PB-KRAS, Int-Hypoxia, and Cycling stage. PB-KRAS cells exhibited stem-like transcriptional programs and high genomic instability. Deconvolution analysis of bulk RNA-seq data from the independent AoV cohort revealed that enrichment of the PB-KRAS subtype correlated with tumor recurrence and poor survival. Our immune profiling analysis discovered a significant association between PB-KRAS subtype and GZMK+ CD8+ T cells, which are in a pre-dysfunctional state, alongside SPP1+ macrophages exhibiting immunosuppressive traits. Spatial transcriptome data further supports the immunosuppressive natures of TME around PB-KRAS subtype malignant epithelial cells in AoV carcinoma. CONCLUSIONS: Our study presents a single-cell atlas of AoV carcinoma, highlighting the molecular diversity of malignant epithelium and its association with the immune microenvironment. The PB-KRAS subtype emerges as a stem-like, immunosuppressive tumor state associated with poor prognosis, providing insights for future therapeutic targeting.

Ampulla of Vater carcinoma↗

Benchmarking computational decontamination of ambient RNA.

Gene expression profiling of single cells using single-cell and single-nucleus RNA sequencing (sxRNA-seq) enables researchers to characterize cellular heterogeneity and unraveling complex biological processes at unprecedented resolution. However, sxRNA-seq faces challenges due to the presence of ambient RNA, extraneous RNA molecules not originating from the cells of interest. Sample preparation is a major source of ambient RNA, where harsh conditions can lead to cell lysis and the release of intracellular RNA. This inescapable inclusion of ambient RNA can cause erroneous results and hinder downstream analyses. To address this issue, various methodologies have been developed to identify, quantify, and remove ambient RNA. Here, we rigorously evaluate 7 state-of-the-art methodologies for ambient RNA removal using simulated datasets, species-mixing experiments of varying complexities, and genotype-mixing experiments. We find that no single method performs the best across all datasets and metrics, but CellBender, DecontX and SoupX generally perform well.

ambient RNA↗