Fernandez, Jenna

ABSTRACT Background Primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) are rare, chronic cholestatic liver diseases with heterogeneous progression and limited biomarkers of disease biology. Epigenetic age acceleration has been demonstrated in PSC and PBC, suggesting accelerated biological aging. DNA methylation–derived telomere length (DNAmTL) reflects replicative aging and cellular turnover, but its role in PSC and PBC remains unclear. We aimed to evaluate DNAmTL in PSC and PBC and its association with disease severity. Methods We analysed and compared DNAmTL and age‐adjusted DNAmTL among patients with PSC ( n = 474) versus PSC controls ( n = 484) and patients with PBC ( n = 291) versus PBC controls ( n = 291). Associations with clinical outcomes were assessed using nonparametric tests and multivariable logistic regression models. Correlations with primary sclerosing cholangitis Risk Estimate Tool (PREsTO) score and epigenetic age acceleration (AgeAccelGrim) were evaluated using linear regression. Results Patients with PSC demonstrated significantly shorter age‐adjusted DNAmTL compared with controls (median −0.036 vs. 0.016, p < 0.001). Patients with PBC also exhibited reduced DNAmTL relative to controls (median 6.814 vs. 6.885, p < 0.001). Within PSC, shorter DNAmTL was associated with cirrhosis (OR 0.21, 95% CI 0.06–0.69, p = 0.013) and advanced disease (OR 0.20, 95% CI 0.06–0.67, p = 0.009). Shorter DNAmTL was also observed in hepatic decompensation and hepatobiliary malignancy, including cholangiocarcinoma. DNAmTL inversely correlated with PReSTO score ( p < 0.001). DNAmTL was strongly inversely correlated with AgeAccelGrim in both PSC and PBC ( p < 0.001). Conclusion Cholestatic liver diseases are associated with shortened DNAmTL, which independently correlates with disease severity in PSC. Together with epigenetic age acceleration, these findings support a model of accelerated biological aging in PSC and PBC characterized by converging signatures of accelerated biological aging that may contribute to progressive biliary injury and fibrosis.

Abstract TET2 mutations (mTET2) are common genetic events in myeloid malignancies and clonal hematopoiesis. These mutations arise in the founding clone and are implicated in many clinical sequelae associated with oncogenic feedforward inflammatory circuits. However, the direct downstream effector of mTET2 responsible for the potentiation of these inflammatory circuits is unknown. To address this, we performed scRNA-seq and scATAC-seq in patients with COVID-19 with and without TET2-mutated clonal hematopoiesis reasoning that inflammation from COVID-19 may highlight critical downstream transcriptional targets of mTET2. Using this approach, we identified metastasis-associated lung adenoma transcript 1 (MALAT1), a therapeutically tractable lncRNA, as a central downstream effector of mTET2 that is both necessary and sufficient to induce the oncogenic proinflammatory features of mTET2 in vivo. We also elucidate the mechanism by which mTET2 upregulate MALAT1 and describe an interaction between MALAT1 and p65, which leads to RNA “shielding” from protein phosphatase 2A dephosphorylation, thus preventing resolution of inflammatory signaling. Significance: This work identifies MALAT1 as a requisite downstream effector of oncogenic feedforward inflammatory circuits necessary for the development of TET2-mutated CH and fulminant myeloid malignancy. We elucidate a novel mechanism by which MALAT1 “shields” p65 from dephosphorylation to potentiate this circuit and nominate MALAT1 inhibition as a future therapeutic strategy.

The snATAC + snRNA platform allows epigenomic profiling of open chromatin and gene expression with single-cell resolution. The most critical assay step is to isolate high-quality nuclei to proceed with droplet-base single nuclei isolation and barcoding. With the increasing popularity of multiomic profiling in various fields, there is a need for optimized and reliable nuclei isolation methods, mainly for human tissue samples. Herein we compared different nuclei isolation methods for cell suspensions, such as peripheral blood mononuclear cells (PBMC, n = 18) and a solid tumor type, ovarian cancer (OC, n = 18), derived from debulking surgery. Nuclei morphology and sequencing output parameters were used to evaluate the quality of preparation. Our results show that NP-40 detergent-based nuclei isolation yields better sequencing results than collagenase tissue dissociation for OC, significantly impacting cell type identification and analysis. Given the utility of applying such techniques to frozen samples, we also tested frozen preparation and digestion (n = 6). A paired comparison between frozen and fresh samples validated the quality of both specimens. Finally, we demonstrate the reproducibility of scRNA and snATAC + snRNA platform, by comparing the gene expression profiling of PBMC. Our results highlight how the choice of nuclei isolation methods is critical for obtaining quality data in multiomic assays. It also shows that the measurement of expression between scRNA and snRNA is comparable and effective for cell type identification.