Project description:Introduction of Hermansky-Pudlak Syndrome-associated mutations with CRISPR/Cas9 genome editing, allows for disease modeling in 3D cultures of hPSC-derived lung organoids.
Project description:Hermansky-Pudlak syndrome (HPS), particularly in types 1 and 4, is characterized by progressive pulmonary fibrosis, a major cause of morbidity and mortality. However, the precise mechanisms driving pulmonary fibrosis in HPS are not fully elucidated. Our previous studies have suggested that CHI3L1-driven fibroproliferation may be a significant factor in HPS-associated fibrosis. This study aimed to explore the role of CHI3L1-CRTH2 interaction on ILC2s and explored the potential contribution of ILC2-fibroblast crosstalk in the development of pulmonary fibrosis in HPS. We identified ILC2s in lung tissues from idiopathic pulmonary fibrosis (IPF) and HPS patients. Our findings suggest that ILC2s may directly stimulate the proliferation and differentiation of primary lung fibroblasts partially through Areg-EGFR-dependent mechanisms. Additionally, specific overexpression of CHI3L1 in the ILC2 population using the IL-7Rcre driver, which was associated with increased fibroproliferation, indicates that ILC2-mediated, CRTH2-dependent mechanisms might contribute to optimal CHI3L1-induced fibroproliferative repair in HPS-associated pulmonary fibrosis.
Project description:Mendelian diseases that present with immune-mediated disorders can provide insights into the molecular mechanisms that drive inflammation. Hermansky-Pudlak syndrome (HPS) types 1 and 4 are caused by defective vesicle trafficking involving the BLOC-3 complex. The presence of inflammatory complications such as Crohn’s disease-like inflammation and lung fibrosis in these patients remains enigmatic. Using mass cytometry we observe an augmented inflammatory monocyte compartment in HPS1 patient peripheral blood that may be associated with a TNF - and IL-1α-dominated cytokine dysregulation. HPS1 patient monocyte-derived macrophages express an inflammatory TNF-OSM mRNA gene signature and changes in lipid metabolism. Using stimulation experiments and lysosomal proteomics we show that defective lipid metabolism drives RAB32-dependent mTOR signaling, facilitated by the accumulation of mTOR on lysosomes. This pathogenic circuit translates into aberrant bacterial clearance, which can be rescued with mTORC1 inhibition. We reveal that a pathogenic lipid-mTOR signaling circuit acts as a metabolic checkpoint for defective anti-microbial activity. This mechanism may be relevant to the complex pathology of HPS1 patients featuring macrophage lipid accumulation, granuloma formation, defective anti-microbial activity and tissue inflammation. Lastly, this circuit may be present in a wider group of disorders with defective lipid metabolism and cholesterol accumulation.
Project description:The human small airway epithelium (SAE) plays a central role in the early events in the pathogenesis of most chronic inherited and acquired lung disorders. Little is known about the molecular phenotypes of the specific cell populations comprising the SAE, and the contribution of specific cell populations to the pathogenesis of human disease. There was cell type-specific expression of the genes relevant to the pathogenesis of the inherited pulmonary disorders, genes associated with risk of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), and (non-mutated) driver genes for lung cancers. Some unexpected observations included high expression of CFTR (cystic fibrosis) and SCNN1A and B (bronchiectasis) in ionocytes, DTNBP1 (Hermansky-Pudlak syndrome) in mast cells, FAM13A (COPD) in neuroendocrine cells, RIN3 (COPD) in mast cells, NSPA1L (IPF) in neuroendocrine cells and a variety of lung cancer-related genes expressed in different cell types that, if mutated, become driver genes. Cigarette smoking significantly altered the cell-specific transcriptome of the different cell populations. Many of the genes relevant to the hereditary and acquired disorders exhibited cell-specific modulation by cigarette smoking, including MUC5B (IPF) down-regulation specifically in intermediate, club and mucus-producing cells and SFTPB (surfactant deficiency) up-regulation in ionocytes.
