Project description:Cystic fibrosis (CF)-related diabetes (CFRD) is an increasingly common and devastating comorbidity of CF, affecting ~35% of adults with CF. However, the underlying causes of CFRD are unclear. Here, we examined cystic fibrosis transmembrane conductance regulator (CFTR) islet expression and whether the CFTR participates in islet endocrine cell function using murine models of b cell CFTR deletion, and normal and CF human pancreas and islets. Specific deletion of CFTR from murine b cells did not affect b cell function. In human islets, CFTR mRNA was minimally expressed, and CFTR protein/electrical activity was not detected. Isolated CF/CFRD islets demonstrated appropriate insulin and glucagon secretion with few changes in key islet-regulatory transcripts. Furthermore, ~65% of b cell area was lost in CF donors, compounded by pancreatic remodeling and immune infiltration of the islet. These results indicate that CFRD is not caused by intrinsic islet dysfunction from CFTR mutation, but rather, by b cell loss and intra-islet inflammation in the setting of a complex pleiotropic disease
Project description:Loss of CFTR function in the pancreatic duct leads to dysregulated luminal pH causing premature activation of digestive enzymes and tissue necrosis. Drastic alterations in pancreatic tissue architecture and cellular composition changes the microenvironment of the islets. Given that CFTR is expressed in the pancreatic ducts, we hypothesized that loss of functional CFTR impacts islet function by modifying the ductal secretome. To this end, we developed a long-term in vitro pancreatic duct epithelial cell culture system and polarized both WT and CFTR-KO (CF) ferret duct epithelial cells. We profiled the apical and basolateral secretome, and the cellular proteome of both WT and CF duct epithelium using quantitative mass spectrometry. Bioinformatic analysis of differentially secreted proteins mapped to their cognate receptors provided a list of putative paracrine interactions that affect islet function. Signaling pathways and upstream regulators that alter the secretome and cellular proteome profile were computationally mined to characterize disease causing mechanisms. In this study, we provide a proteomic roadmap of perturbed autocrine and paracrine signals from the CF pancreatic duct.
Project description:Purpose: To identify the cell types that contribute to CFTR expression and function within the proximal-distal axis of the normal human lung. Methods: Single cell RNA-seq (scRNA-seq) was performed on freshly isolated human large and small airway epithelial cells. Single cell-based RNA in situ hybridization (scRNA-ISH) and quantitative RT-PCR (scqRT-PCR) were performed for validation. In vitro culture systems correlated CFTR function to cell types. Lentiviruses were used for cell-type specific transduction of wild-type CFTR in CF cells. Results: scRNA-seq identified secretory cells as dominating CFTR expression in normal human large and particularly small airways, followed by basal cells. Ionocytes expressed the highest CFTR levels but were rare, while expression in ciliated cells was infrequent and low. scRNA-ISH, and scqRT-PCR confirmed the scRNA-seq findings. CF lungs exhibited distributions of CFTR and ionocytes similar to normal controls. CFTR-mediated Cl- secretion tracked secretory cell, not ionocyte, densities. Further, the nucleotide-purinergic regulatory system that controls CFTR-mediated hydration was associated with secretory cells. Lentiviral transduction of wild-type CFTR produced CFTR-mediated Cl- secretion in CF airway secretory cells but not ciliated cells. Conclusions: Secretory cells dominate CFTR expression and function in human airway superficial epithelia. CFTR therapies may need to restore CFTR function to multiple cell types, with a focus on secretory cells.
Project description:Purpose: To identify the cell types that contribute to CFTR expression and function within the proximal-distal axis of the normal human lung. Methods: Single cell RNA-seq (scRNA-seq) was performed on freshly isolated human large and small airway epithelial cells. Single cell-based RNA in situ hybridization (scRNA-ISH) and quantitative RT-PCR (scqRT-PCR) were performed for validation. In vitro culture systems correlated CFTR function to cell types. Lentiviruses were used for cell-type specific transduction of wild-type CFTR in CF cells. Results: scRNA-seq identified secretory cells as dominating CFTR expression in normal human large and particularly small airways, followed by basal cells. Ionocytes expressed the highest CFTR levels but were rare, while expression in ciliated cells was infrequent and low. scRNA-ISH, and scqRT-PCR confirmed the scRNA-seq findings. CF lungs exhibited distributions of CFTR and ionocytes similar to normal controls. CFTR-mediated Cl- secretion tracked secretory cell, not ionocyte, densities. Further, the nucleotide-purinergic regulatory system that controls CFTR-mediated hydration was associated with secretory cells. Lentiviral transduction of wild-type CFTR produced CFTR-mediated Cl- secretion in CF airway secretory cells but not ciliated cells. Conclusions: Secretory cells dominate CFTR expression and function in human airway superficial epithelia. CFTR therapies may need to restore CFTR function to multiple cell types, with a focus on secretory cells.
Project description:To unravel CFTR function in endothelial cells (HUVECs), we used two complementary approaches to induce CFTR blockade: (i) the allosteric CFTR inhibitor CFTRinh-(172) which is commonly used in CF research, and (ii) CFTR-specific short hairpin RNAs (shRNA).
Project description:Production of functional proteins requires multiple steps including gene transcription and post-translational processing. MicroRNAs (miRNA) can regulate individual stages of these processes. Despite the importance of the cystic fibrosis transmembrane conductance regulator (CFTR) channel for epithelial anion transport, how its expression is regulated remains uncertain. We discovered that microRNA-138 regulates CFTR expression through its interactions with the transcriptional regulatory protein SIN3A. Treating airway epithelia with a miR-138 mimic increased CFTR mRNA and also enhanced CFTR abundance and transepithelial Cl- permeability independently of elevated mRNA levels. A miR-138 anti-miR had the opposite effects. Importantly, miR-138 altered the expression of many genes encoding proteins that associate with CFTR and may influence its biosynthesis. The most common CFTR mutation, M-NM-^TF508, causes protein misfolding, degradation, and cystic fibrosis. Remarkably, manipulating the miR-138 regulatory network also improved biosynthesis of CFTR-M-NM-^TF508 and restored Cl- transport to cystic fibrosis airway epithelia. This novel miRNA-regulated network directs gene expression from the chromosome to the cell membrane, indicating that an individual miRNA can control a cellular process broader than previously recognized. This discovery also provides new therapeutic avenues for restoring CFTR function to cells affected by the most common cystic fibrosis mutation. 12 samples of Calu-3 cells representing different interventions.
Project description:The purpose of this study was to explore baseline expression of miRNome in Cystic Fibrosis Bronchial Epithelial (CFBE41o-) cells stably transfected with wild type (WT) Cystic Fibrosis Transmembrane Conductance regulator (CFTR) and F508del-CFTR. To fulfill this goal miRNA sequencing was done to see miRNA landscape in CFBE41o- Cells with homozygous F508del mutated CFTR and in CFBE41o- Cells with homozygous WT-CFTR, without any treatment condition.
Project description:Production of functional proteins requires multiple steps including gene transcription and post-translational processing. MicroRNAs (miRNA) can regulate individual stages of these processes. Despite the importance of the cystic fibrosis transmembrane conductance regulator (CFTR) channel for epithelial anion transport, how its expression is regulated remains uncertain. We discovered that microRNA-138 regulates CFTR expression through its interactions with the transcriptional regulatory protein SIN3A. Treating airway epithelia with a miR-138 mimic increased CFTR mRNA and also enhanced CFTR abundance and transepithelial Cl- permeability independently of elevated mRNA levels. A miR-138 anti-miR had the opposite effects. Importantly, miR-138 altered the expression of many genes encoding proteins that associate with CFTR and may influence its biosynthesis. The most common CFTR mutation, ΔF508, causes protein misfolding, degradation, and cystic fibrosis. Remarkably, manipulating the miR-138 regulatory network also improved biosynthesis of CFTR-ΔF508 and restored Cl- transport to cystic fibrosis airway epithelia. This novel miRNA-regulated network directs gene expression from the chromosome to the cell membrane, indicating that an individual miRNA can control a cellular process broader than previously recognized. This discovery also provides new therapeutic avenues for restoring CFTR function to cells affected by the most common cystic fibrosis mutation.
Project description:Blood vessels play a critical role in pancreatic islet health and function, yet current culture methods to generate islet organoids from human pluripotent stem cells (SC-islets) lack a vascular component. Here, we engineered 3D vascularized SC-islet organoids by assembling SC-islet cells, human primary endothelial cells (ECs) and fibroblasts both in a non-perfused model and a microfluidic device with perfused vessels. Vasculature improved stimulus-dependent Ca2+ influx into SC-β-cells; a hallmark of β-cell function that is blunted in non-vascularized SC-islets. We show that an islet-like basement membrane is formed by vasculature and contributes to the functional improvement of SC-β-cells. Furthermore, cell-cell communication networks based on scRNA-seq data predicted BMP2/4-BMPR2 signaling from ECs to SC-β-cells. Correspondingly, BMP4 augmented the SC-β-cell Ca2+ response and insulin secretion. The here-described vascularized SC-islet models will enable further studies of crosstalk between β-cells and ECs and serve as an in vivo-mimicking platform for disease modeling and therapeutic testing.
Project description:Dll4-Notch signaling is required for cell fate decisions and neoplasias. However, emerging evidence suggests a role for Dll4-Notch signaling in metabolic and immune diseases. To date, there is no evidence of a direct effect of Dll4-Notch signaling inhibition on pancreatic islet function and insulin secretion.