Project description:Oncogenic KrasG12D, a driver mutation of pancreatic ductal adenocarcinoma (PDAC), induces neoplastic transformation of acinar cells through acinar-to-ductal metaplasia (ADM). Here, we show that both functional complexes of mTOR (mechanistic target of rapamycin kinase, mTORC1 and mTORC2) are specifically activated in ADM. Murine models uncover that mTORC1 and mTORC2 cooperate to promote KrasG12D-driven ADM development. Proteomic analyses identify Arp2/3 complex, an actin nucleator, as the common downstream effector: mTORC1 is responsible for the protein synthesis of Rac1 and Arp3 while mTORC2 promotes the Arp2/3 complex activity via Akt/Rac1 signalling. Genetic ablation of Arp2/3 complex completely arrests KrasG12D-driven ADM development. The Arp2/3 complex-mediated y-branching of actin network promotes the basolateral spread of filamentous actin, which is indispensable for acinar cells-initiated carcinogenesis. Induced by oncogenic KrasG12D, ADM is a metaplastic phenotype of acinar cells that requires extensive actin rearrangements. mTORC1 and mTORC2, downstream targets of KrasG12D, have well-established oncogenic functions in PDAC development. The actin-related protein 2/3 (Arp2/3) complex is the first identified actin nucleator. Regarded as textbook knowledge, it is activated by EGFR/Rac1 signalling to promote the polymerisation of branched actin filaments from pre-existing filaments in numerous biological contexts. Hereby, we identify that mTORC1 and mTORC2 attain a dual, yet non-redundant, regulatory role in promoting Arp2/3 complex function, which is responsible for generating basolateral filamentous actin in ADM. Thus, the role of Arp2/3 complex fills up the missing gap between putative oncogenic signals and actin dynamics underlying PDAC initiation.
Project description:Acinar cells have been proposed as a cell-of-origin for pancreatic intraepithelial neoplasia (PanIN) after undergoing a highly regulated acinar to ductal metaplasia (ADM) process. ADM can be triggered by pancreatitis causing acinar cells de-differentiate to a ductal-like state. We identify Fra1 (gene name Fosl1) as the most enriched transcription factor during KrasG12D acute pancreatitis mediated injury. We have elucidated the functional role of Fra1 by generating an acinar-specific Fosl1 knockout mouse expressing KrasG12D (Ptf1aCreERT;KrasG12D;Fosl1fl/fl;YFP) . Using single nuclei ATAC-seq and bulk-RNA seq, we used pseudotime analysis and developed a gene-regulatory network governing de-differentiation to demonstrate that Fosl1 knockout mice are delayed in the onset of ADM and accompanying recovery. Fosl1 depletion prevents the pro-inflammatory effects of G-CSF, an ADM-promoting cytokine, suggesting that the G-CSF/Fra1 signaling axis can modulate ADM. Overall, our studies mark the first time a discrete transcriptional factor has been linked to the temporal regulation of ADM.
Project description:Acinar cells have been proposed as a cell-of-origin for pancreatic intraepithelial neoplasia (PanIN) after undergoing a highly regulated acinar to ductal metaplasia (ADM) process. ADM can be triggered by pancreatitis causing acinar cells de-differentiate to a ductal-like state. We identify Fra1 (gene name Fosl1) as the most enriched transcription factor during KrasG12D acute pancreatitis mediated injury. We have elucidated the functional role of Fra1 by generating an acinar-specific Fosl1 knockout mouse expressing KrasG12D (Ptf1aCreERT;KrasG12D;Fosl1fl/fl;YFP) . Using single nuclei ATAC-seq and bulk-RNA seq, we used pseudotime analysis and developed a gene-regulatory network governing de-differentiation to demonstrate that Fosl1 knockout mice are delayed in the onset of ADM and accompanying recovery. Fosl1 depletion prevents the pro-inflammatory effects of G-CSF, an ADM-promoting cytokine, suggesting that the G-CSF/Fra1 signaling axis can modulate ADM. Overall, our studies mark the first time a discrete transcriptional factor has been linked to the temporal regulation of ADM.
Project description:Bronchopulmonary dysplasia (BPD) is a chronic lung disease commonly affecting premature infants, with limited therapeutic options and increased long-term consequences. Adrenomedullin (Adm), a proangiogenic peptide hormone, has been found to protect rodents against experimental BPD. This study aims to elucidate the molecular and cellular mechanisms through which Adm influences BPD pathogenesis using a lipopolysaccharide (LPS)-induced model of experimental BPD in mice. Bulk RNA sequencing of Adm-sufficient (wild-type or Adm+/+) and Adm-haplodeficient (Adm+/-) mice lungs, integrated with single-cell RNA sequencing data, revealed distinct gene expression patterns and cell type alterations associated with Adm deficiency and LPS exposure. Notably, computational integration with cell atlas data revealed that Adm-haplodeficient mouse lungs exhibited gene expression signatures characteristic of increased inflammation, natural killer (NK) cell frequency and decreased endothelial cell and type II pneumocyte frequency. Furthermore, in silico human BPD patient data analysis supported our cell type frequency finding, highlighting elevated NK cells in BPD infants. These results underscore the protective role of Adm in experimental BPD and emphasize that it is a potential therapeutic target for BPD infants with an inflammatory phenotype.
Project description:Bronchopulmonary dysplasia (BPD) is the major cause of chronic lung disease (CLD) and morbidity in preterm infants, which characterized by impaired pulmonary alveolar development in preterm infants. There is increasing evidence that micro RNA (miRNA) has a close association with the development of pulmonary diseasesincluding lung growth, pulmonary fibrosis, pneumonia, etc. The potential role of miRNA in the pathogenesis of BPD is unclear. This study aims to clarify the role of adrenomedullin (ADM) regulated by miRNA-547-3p during the process of BPD and illustrate the protective effect of ADM involved in preterm infants.We indentified the differential expressed miRNA and their potential target genes, microarray analysis using Agilent Human 4x44K Gene Expression Microarrays v2 and miRCURY LNA™ microRNA Array was performed. The results of miRNA chip were scanned by Axon GenePix 4000B and the signal of probes were read by GenePix Pro 6.0 software. Only the target genes which exist in both two databases and having different expression trend were remained. Thus, miRNA-574-3p and it’s target gene ADM were selected to do the further research in our study. And we verified miRNA-574-3p and ADM expression in BPD premature infants by realtime q-PCR. After the microarray expression analysis, there were 516 probes differential expressed between BPD samples and normal samples. Among them, 510 were up-regulated and 213 were down-regulated. Meanwhile, to the miRNA aspect, there were 37 up-regulated and 44 down-regulated. After text mining, we found ADM was already found play a role in BPD. ADM is an endogenous peptide with potent angiogenic, anti-oxidant, and anti-inflammatory properties. Realtime q-PCR assay results showed that, miRNA-574-3p expression level in blood samples from preterm infants with BPD was significantly decreased, ADM expression level in blood samples from preterm infants with BPD was significantly increased. In our study, we found that up-regulation of ADM regulated by miRNA-574-3p could protect preterm infants with BPD. These data provide novel insights into ADM regulated by miRNA-574-3p which may be shed light on BPD prevention and treatment.
Project description:Preeclampsia (PE) is the leading cause of prenatal morbidity and mortality. It is associated with defective trophoblast functions at implantation, but manifestation of its phenotypes is in late pregnancy. There is no reliable method for early prediction and treatment of PE. Adrenomedullin (ADM) is an abundant placental peptide in early pregnancy. Here, integrated single-cell sequencing and spatial transcriptomics confirm a high ADM expression in the human villous cytotrophoblast. The levels of ADM in chorionic villi and serum were lower in first-trimester pregnant women who later developed PE than those with normotensive pregnancy. ADM stimulates differentiation of trophoblast stem cells and trophoblast organoids in vitro. In pregnant mice, placenta-specific ADM suppression led to PE-like phenotypes. The PE-like phenotypes in a mouse PE model were reduced by a novel placenta-specific nanoparticle-based forced expression of ADM. Our study reveals the roles of trophoblastic ADM in placental development, PE pathogenesis and its potential clinical uses.
Project description:Acinar cells have been proposed as a cell-of-origin for pancreatic intraepithelial neoplasia (PanIN) after undergoing a highly regulated acinar to ductal metaplasia (ADM) process. ADM can be triggered by pancreatitis causing acinar cells de-differentiate to a ductal-like state. We identify Fra1 (gene name Fosl1) as the most enriched transcription factor during KrasG12D acute pancreatitis mediated injury. We have elucidated the functional role of Fra1 by generating an acinar-specific Fosl1 knockout mouse expressing KrasG12D (Ptf1aCreERT;KrasG12D;Fosl1fl/fl;YFP) . Using single nuclei ATAC-seq and bulk-RNA seq, we used pseudotime analysis and developed a gene-regulatory network governing de-differentiation to demonstrate that Fosl1 knockout mice are delayed in the onset of ADM and accompanying recovery. Fosl1 depletion prevents the pro-inflammatory effects of G-CSF, an ADM-promoting cytokine, suggesting that the G-CSF/Fra1 signaling axis can modulate ADM. Overall, our studies mark the first time a discrete transcriptional factor has been linked to the temporal regulation of ADM.
Project description:This study describes a novel function for the ST6GAL1 sialyltransferase in promoting acinar to ductal metaplasia (ADM). ST6GAL1 activity facilitates ADM by reprogramming acinar cells into a more progenitor-like state.
Project description:In order to compare the gene expression profile of acinar-to-ductal metaplasia (ADM), ductal and acinar cells in the setting of pancreatitis, which were obtained by laser-capture microdissection (LMD) from frozen sections of wild type mice pancreata 2 days after caerulein administration, we performed microarray analysis. ADM has an intermediate property between ductal and acinar cells in the setting of pancreatitis, and Cxcr4 mRNA which is expressed in multipotent pancreatic progenitors, were up-regulated in ADM compared with ductal cells or acinar cells. Notably, in consistent with our immunostaining data, Dclk1 mRNA was highly expressed in ADM cells compared with ductal and acinar cells.
Project description:Acinar ductal metaplasia (ADM), is believed to be one of the earliest precursor lesions towards the development of pancreatic ductal adenocarcinoma, and maintaining the pancreatic acinar cell phenotype suppresses tumor formation. We report that pStat3 and HDAC inhibition can attenuate ADM in vitro and TSA treatment reverses the dedifferentiated phenotype to one that is more acinar. Our findings suggest that pharmacological inhibition or reversal of pancreatic ADM represents a potential therapeutic strategy for blocking ductal reprogramming of acinar cells.