Conserved long noncoding RNA TILAM promotes liver fibrosis through interaction with PML in HSCs.

BACKGROUND AND AIMS: Fibrosis is the common end point for all forms of chronic liver injury, and the progression of fibrosis leads to the development of end-stage liver disease. Activation of HSCs and their transdifferentiation into myofibroblasts results in the accumulation of extracellular matrix proteins that form the fibrotic scar. Long noncoding RNAs regulate the activity of HSCs and provide targets for fibrotic therapies. APPROACH AND RESULTS: We identified long noncoding RNA TILAM located near COL1A1 , expressed in HSCs, and induced with liver fibrosis in humans and mice. Loss-of-function studies in human HSCs and human liver organoids revealed that TILAM regulates the expression of COL1A1 and other extracellular matrix genes. To determine the role of TILAM in vivo, we annotated the mouse ortholog ( Tilam ), generated Tilam- deficient green fluorescent protein-reporter mice, and challenged these mice in 2 different models of liver fibrosis. Single-cell data and analysis of single-data and analysis of Tilam-deficient reporter mice revealed that Tilam is induced in murine HSCs with the development of fibrosis in vivo. Tilam -deficient reporter mice revealed that Tilam is induced in murine HSCs with the development of fibrosis in vivo. Furthermore, loss of Tilam expression attenuated the development of fibrosis in the setting of in vivo liver injury. Finally, we found that TILAM interacts with promyelocytic leukemia nuclear body scaffold protein to regulate a feedback loop by which TGF-ß2 reinforces TILAM expression and nuclear localization of promyelocytic leukemia nuclear body scaffold protein to promote the fibrotic activity of HSCs. CONCLUSIONS: TILAM is activated in HSCs with liver injury and interacts with promyelocytic leukemia nuclear body scaffold protein to drive the development of fibrosis. Depletion of TILAM may serve as a therapeutic approach to combat the development of end-stage liver disease.

Conserved long noncoding RNA TILAM promotes liver fibrosis through interaction with PML in hepatic stellate cells.

Background & Aims: Fibrosis is the common endpoint for all forms of chronic liver injury, and progression of fibrosis leads to the development of end-stage liver disease. Activation of hepatic stellate cells (HSCs) and their transdifferentiation to myofibroblasts results in the accumulation of extracellular matrix (ECM) proteins that form the fibrotic scar. Long noncoding (lnc) RNAs regulate the activity of HSCs and may provide targets for fibrotic therapies. Methods: We identified lncRNA TILAM as expressed near COL1A1 in human HSCs and performed loss-of-function studies in human HSCs and liver organoids. Transcriptomic analyses of HSCs isolated from mice defined the murine ortholog of TILAM . We then generated Tilam -deficient GFP reporter mice and quantified fibrotic responses to carbon tetrachloride (CCl 4 ) and choline-deficient L-amino acid defined high fat diet (CDA-HFD). Co-precipitation studies, mass spectrometry, and gene expression analyses identified protein partners of TILAM . Results: TILAM is conserved between human and mouse HSCs and regulates expression of ECM proteins, including collagen. Tilam is selectively induced in HSCs during the development of fibrosis in vivo . In both male and female mice, loss of Tilam results in reduced fibrosis in the setting of CCl 4 and CDA-HFD injury models. TILAM interacts with promyelocytic leukemia protein (PML) to stabilize PML protein levels and promote the fibrotic activity of HSCs. Conclusion: TILAM is activated in HSCs and interacts with PML to drive the development of liver fibrosis. Depletion of TILAM may serve as a therapeutic approach to combat the development of end stage liver disease.

Mapping lung tumor cell drug responses as a function of matrix context and genotype using cell microarrays.

Carcinoma progression is influenced by interactions between epithelial tumor cells and components of their microenvironment. In particular, cell-extracellular matrix (ECM) interactions are known to drive tumor growth, metastatic potential, and sensitivity or resistance to therapy. Yet the intrinsic complexity of ECM composition within the tumor microenvironment remains a barrier to comprehensive investigation of these interactions. We present here a high-throughput cell microarray-based approach to study the impact of defined combinations of ECM proteins on tumor cell drug responses. Using this approach, we quantitatively evaluated the effects of 55 different ECM environments representing all single and two-factor combinations of 10 ECM proteins on the responses of lung adenocarcinoma cells to a selection of cancer-relevant small molecule drugs. This drug panel consisted of an alkylating agent and five receptor tyrosine kinase inhibitors. We further determined that expression of the neuroendocrine transcription factor ASCL1, which has been previously associated with poor patient outcome when co-expressed with the RET oncogene, altered cell responses to drugs and modulated cleavage of the pro-apoptotic protein caspase-3 depending on ECM context. Our results suggest that co-expression of specific ECM proteins with known genetic drivers in lung adenocarcinoma may impact therapeutic efficacy. Furthermore, this approach could be utilized to define the molecular mechanisms by which cell-matrix interactions drive drug resistance through integration with clinical cell samples and genomics data.