Diversity of CFTR variants across ancestries characterized using 454,727 UK biobank whole exome sequences.

BACKGROUND: Limited understanding of the diversity of variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene across ancestries hampers efforts to advance molecular diagnosis of cystic fibrosis (CF). The consequences pose a risk of delayed diagnoses and subsequently worsened health outcomes for patients. Therefore, characterizing the spectrum of CFTR variants across ancestries is critical for revolutionizing molecular diagnoses of CF. METHODS: We analyzed 454,727 UK Biobank (UKBB) whole-exome sequences to characterize the diversity of CFTR variants across ancestries. Using the PanUKBB classification, the participants were assigned into six major groups: African (AFR), American/American Admixed (AMR), Central South Asia (CSA), East Asian (EAS), European (EUR), and Middle East (MID). We segregated ancestry-specific CFTR variants, including those that are CF-causing or clinically relevant. The ages of certain CF-causing variants were determined and analyzed for selective pressure effects, and curated phenotype analysis was performed for participants with clinically relevant CFTR genotypes. RESULTS: We detected over 4000 CFTR variants, including novel ancestry-specific variants, across six ancestries. Europeans had the most unique CFTR variants [n = 2212], while the American group had the least unique variants [n = 23]. F508del was the most prevalent CF-causing variant found in all ancestries, except in EAS, where V520F was the most prevalent. Common EAS variants such as 3600G > A, V456A, and V520, which appeared approximately 270, 215, and 338 generations ago, respectively, did not show evidence of selective pressure. Sixteen participants had two CF-causing variants, with two being diagnosed with CF. We found 154 participants harboring a CF-causing and varying clinical consequences (VCC) variant. Phenotype analysis performed for participants with multiple clinically relevant variants returned significant associations with CF and its pulmonary phenotypes [Bonferroni-adjusted p < 0.05]. CONCLUSIONS: We leveraged the UKBB database to comprehensively characterize the broad spectrum of CFTR variants across ancestries. The detection of over 4000 CFTR variants, including several ancestry-specific and uncharacterized CFTR variants, warrants the need for further characterization of their functional and clinical relevance. Overall, the presentation of classical CF phenotypes seen in non-CF diagnosed participants with more than one CF-causing variant indicates that they may benefit from current CFTR modulator therapies.

Addressing underrepresentation in genomics research through community engagement.

The vision of the American Society of Human Genetics (ASHG) is that people everywhere will realize the benefits of human genetics and genomics. Implicit in that vision is the importance of ensuring that the benefits of human genetics and genomics research are realized in ways that minimize harms and maximize benefits, a goal that can only be achieved through focused efforts to address health inequities and increase the representation of underrepresented communities in genetics and genomics research. This guidance is intended to advance community engagement as an approach that can be used across the research lifecycle. Community engagement uniquely offers researchers in human genetics and genomics an opportunity to pursue that vision successfully, including by addressing underrepresentation in genomics research.

CFTR-mediated monocyte/macrophage dysfunction revealed by cystic fibrosis proband-parent comparisons.

Cystic fibrosis (CF) is an inherited disorder caused by biallelic mutations of the CF transmembrane conductance regulator (CFTR) gene. Converging evidence suggests that CF carriers with only 1 defective CFTR copy are at increased risk for CF-related conditions and pulmonary infections, but the molecular mechanisms underpinning this effect remain unknown. We performed transcriptomic profiling of peripheral blood mononuclear cells (PBMCs) of CF child-parent trios (proband, father, and mother) and healthy control (HC) PBMCs or THP-1 cells incubated with the plasma of these participants. Transcriptomic analyses revealed suppression of cytokine-enriched immune-related genes (IL-1ß, CXCL8, CREM), implicating lipopolysaccharide tolerance in innate immune cells (monocytes) of CF probands and their parents. These data suggest that a homozygous as well as a heterozygous CFTR mutation can modulate the immune/inflammatory system. This conclusion is further supported by the finding of lower numbers of circulating monocytes in CF probands and their parents, compared with HCs, and the abundance of mononuclear phagocyte subsets, which correlated with Pseudomonas aeruginosa infection, lung disease severity, and CF progression in the probands. This study provides insight into demonstrated CFTR-related innate immune dysfunction in individuals with CF and carriers of a CFTR mutation that may serve as a target for personalized therapy.

Microarray profiling identifies extracellular circulating miRNAs dysregulated in cystic fibrosis.

Extracellular circulating miRNAs (ECmiRNAs) play a crucial role in cell-to-cell communication and serve as non-invasive biomarkers in a wide range of diseases, but their abundance and functional relevance in cystic fibrosis (CF) remain poorly understood. In this study, we employed microarray technology to identify aberrantly expressed plasma ECmiRNAs in CF and elucidate the functional relevance of their targets. Overall, we captured several ECmiRNAs abundantly expressed in CF. Expression levels of 11 ECmiRNAs differed significantly between CF and healthy control (HC) samples (FDR < 0.05, log2 FC≥2). Among these, 10 were overexpressed while only hsa-miR-598-3p was underexpressed in CF. The overexpressed miRNAs included three let-7 family members (hsa-let-7b-5p, hsa-let-7c-5p and hsa-let-7d-5p), three 103/107 family members (hsa-mir-103a-3p; hsa-mir-103b; hsa-mir-107), hsa-miR-486-5p, and other miRNAs. Using in silico methods, we identified 2,505 validated targets of the 11 differentially expressed miRNAs. Hsa-let-7b-5p was the most important hub in the network analysis. The top-ranked validated targets were involved in miRNA biogenesis and gene expression, including AGO1, DICER1, HMGA1, and MYC. The top pathways influenced by all targets were primarily signal transduction pathways associated with CF, including PI3K/Akt-, Wnt/ß catenin-, glucocorticoid receptor-, and mTor signaling pathways. Our results suggest ECmiRNAs may be clinically relevant in CF and warrant further study.

The interaction of YBX1 with G3BP1 promotes renal cell carcinoma cell metastasis via YBX1/G3BP1-SPP1- NF-κB signaling axis.

BACKGROUND: Renal cell carcinoma (RCC) is a deadly urological tumor that remains largely incurable. Our limited understanding of key molecular mechanisms underlying RCC invasion and metastasis has hampered efforts to identify molecular drivers with therapeutic potential. With evidence from our previous study revealing that nuclear overexpression of YBX1 is associated with RCC T stage and metastasis, we investigated the effects of YBX1 in RCC migration, invasion, and adhesion, and then characterized its interaction with RCC-associated proteins G3BP1 and SPP1. METHODS: Renal cancer cell lines, human embryonic kidney cells, and clinical samples were analyzed to investigate the functional role of YBX1 in RCC metastasis. YBX1 knockdown cells were established via lentiviral infection and subjected to adhesion, transwell migration, and invasion assay. Microarray, immunoprecipitation, dual-luciferase reporter assay, and classical biochemical assays were applied to characterize the mechanism of YBX1 interaction with RCC-associated proteins G3BP1 and SPP1. RESULTS: Knockdown of YBX1 in RCC cells dramatically inhibited cell adhesion, migration, and invasion. Mechanistic investigations revealed that YBX1 interaction with G3BP1 upregulated their downstream target SPP1 in vitro and in vivo, which led to an activated NF-κB signaling pathway. Meanwhile, knockdown of SPP1 rescued the YBX1/G3BP1-mediated activation of NF-κB signaling pathway, and RCC cell migration and invasion. We further showed that YBX1 expression was positively correlated with G3BP1 and SPP1 expression levels in clinical RCC samples. CONCLUSIONS: YBX1 interacts with G3BP1 to promote metastasis of RCC by activating the YBX1/G3BP1-SPP1-NF-κB signaling axis.

Transcriptional consequences of impaired immune cell responses induced by cystic fibrosis plasma characterized via dual RNA sequencing.

BACKGROUND: In cystic fibrosis (CF), impaired immune cell responses, driven by the dysfunctional CF transmembrane conductance regulator (CFTR) gene, may determine the disease severity but clinical heterogeneity remains a major therapeutic challenge. The characterization of molecular mechanisms underlying impaired immune responses in CF may reveal novel targets with therapeutic potential. Therefore, we utilized simultaneous RNA sequencing targeted at identifying differentially expressed genes, transcripts, and miRNAs that characterize impaired immune responses triggered by CF and its phenotypes. METHODS: Peripheral blood mononuclear cells (PBMCs) extracted from a healthy donor were stimulated with plasma from CF patients (n = 9) and healthy controls (n = 3). The PBMCs were cultured (1 × 105 cells/well) for 9 h at 37 ° C in 5% CO2. After culture, total RNA was extracted from each sample and used for simultaneous total RNA and miRNA sequencing. RESULTS: Analysis of expression signatures from peripheral blood mononuclear cells induced by plasma of CF patients and healthy controls identified 151 genes, 154 individual transcripts, and 41 miRNAs differentially expressed in CF compared to HC while the expression signatures of 285 genes, 241 individual transcripts, and seven miRNAs differed due to CF phenotypes. Top immune pathways influenced by CF included agranulocyte adhesion, diapedesis signaling, and IL17 signaling, while those influenced by CF phenotypes included natural killer cell signaling and PI3K signaling in B lymphocytes. Upstream regulator analysis indicated dysregulation of CCL5, NF-κB and IL1A due to CF while dysregulation of TREM1 and TP53 regulators were associated with CF phenotype. Five miRNAs showed inverse expression patterns with three target genes relevant in CF-associated impaired immune pathways while two miRNAs showed inverse expression patterns with two target genes relevant to a dysregulated immune pathway associated with CF phenotypes. CONCLUSIONS: Our results indicate that miRNAs and individual transcript variants are relevant molecular targets contributing to impaired immune cell responses in CF.

Cystic Fibrosis Plasma Blunts the Immune Response to Bacterial Infection.

Cystic fibrosis (CF) is caused by mutations of the gene encoding the CF transmembrane conductance regulator. It remains unclear whether the abnormal immune response in CF involves extrinsic signals released from the external or internal environment. We sought to characterize the peripheral immune signatures in CF and its association with clinical phenotypes. Healthy peripheral blood mononuclear cells (PBMCs) were cultured with plasma from CF probands (CFPs) or healthy control subjects (HCs) followed by nCounter gene and microRNA (miRNA) profiling. A discovery cohort of 12 CFPs and 12 HCs and a validation cohort of 103 CFPs and 31 HCs (our previous microarray data [GSE71799]) were analyzed to characterize the composition of cultured immune cells and establish a miRNA‒mRNA network. Cell compositions and miRNA profiles were associated with clinical characteristics of the cohorts. Significantly differentially expressed genes and abundance of myeloid cells were downregulated in PMBCs after culture with CF plasma (P < 0.05). Top-ranked miRNAs that increased in response to CF plasma (adjusted P < 0.05) included miR-155 and miR-146a, which target many immune-related genes, such as IL-8. Pseudomonas aeruginosa infection was negatively associated with abundance of monocytes and the presence of those regulatory miRNAs. Extrinsic signals in plasma from patients with CF led to monocyte inactivation and miRNA upregulation in PBMCs. An improved understanding of the immune effects of extrinsic factors in CF holds great promise for integrating immunomodulatory cell therapies into current treatment strategies in CF.

Transcriptome Profiling and Molecular Therapeutic Advances in Cystic Fibrosis: Recent Insights.

In cystic fibrosis (CF), mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene disrupt the capacity of the encoded protein to function as a channel to transport chloride ions and water across cell membranes. The consequences are deleterious, system-wide, and immensely variable, even among patients with the same CFTR genotype. This underscores the need to characterize the mechanisms contributing to CF pathophysiology. Gene replacement and gene editing therapies have been pursued intensively and are expected to provide a one-time treatment for CF. However, gene replacement therapy is limited by the lack of efficient vectors to deliver functional copies of CFTR to cells without immunological complications, while gene editing technologies such as CRISPR/Cas9 are still in their infancy, mainly useful in somatic cells and limited by off-target insertions. Small molecule treatments targeted at potentiating or correcting CFTR have shown clinical benefits, but they are limited to a few CFTR mutations and insufficient to overcome challenges related to clinical heterogeneity. Transcriptome profiling approaches have emerged as robust tools capable of characterizing phenotypic variability and revealing novel molecular targets with therapeutic potential for CF. We summarize current insights gained through transcriptome profiling approaches in CF studies and recent advances in molecular therapeutics.

Increased Expression of Plasma-Induced ABCC1 mRNA in Cystic Fibrosis.

The ABCC1 gene is structurally and functionally related to the cystic fibrosis transmembrane conductance regulator gene (CFTR). Upregulation of ABCC1 is thought to improve lung function in patients with cystic fibrosis (CF); the mechanism underlying this effect is unknown. We analyzed the ABCC1 promoter single nucleotide polymorphism (SNP rs504348), plasma-induced ABCC1 mRNA expression levels, and ABCC1 methylation status and their correlation with clinical variables among CF subjects with differing CFTR mutations. We assigned 93 CF subjects into disease severity groups and genotyped SNP rs504348. For 23 CF subjects and 7 healthy controls, donor peripheral blood mononuclear cells (PBMCs) stimulated with plasma underwent gene expression analysis via qRT-PCR. ABCC1 promoter methylation was analyzed in the same 23 CF subjects. No significant correlation was observed between rs504348 genotypes and CF disease severity, but pancreatic insufficient CF subjects showed increased colonization with any form of Pseudomonas aeruginosa (OR = 3.125, 95% CI: 1.192-8.190) and mucoid P. aeruginosa (OR = 5.075, 95% CI: 1.307-28.620) compared to the pancreatic sufficient group. A significantly higher expression of ABCC1 mRNA was induced by CF plasma compared to healthy control plasma (p < 0.001). CF subjects with rs504348 (CC/CG) also had higher mRNA expression compared to those with the ancestral GG genotype (p < 0.005). ABCC1 promoter was completely unmethylated; therefore, we did not detect any association between methylation and CF disease severity. In silico predictions suggested that histone modifications are crucial for regulating ABCC1 expression in PBMCs. Our results suggest that ABCC1 expression has a role in CFTR activity thereby increasing our understanding of the molecular underpinnings of the clinical heterogeneity in CF.