1
|
A model for stimulation of enzyme activity by a competitive inhibitor based on the interaction of terazosin and phosphoglycerate kinase 1. Proc Natl Acad Sci U S A 2024; 121:e2318956121. [PMID: 38377207 PMCID: PMC10907273 DOI: 10.1073/pnas.2318956121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/21/2024] [Indexed: 02/22/2024] Open
Abstract
The drug terazosin (TZ) binds to and can enhance the activity of the glycolytic enzyme phosphoglycerate kinase 1 (PGK1) and can increase ATP levels. That finding prompted studies of TZ in Parkinson's disease (PD) in which decreased neuronal energy metabolism is a hallmark feature. TZ was neuroprotective in cell-based and animal PD models and in large epidemiological studies of humans. However, how TZ might increase PGK1 activity has remained a perplexing question because structural data revealed that the site of TZ binding to PGK1 overlaps with the site of substrate binding, predicting that TZ would competitively inhibit activity. Functional data also indicate that TZ is a competitive inhibitor. To explore the paradoxical observation of a competitive inhibitor increasing enzyme activity under some conditions, we developed a mass action model of TZ and PGK1 interactions using published data on PGK1 kinetics and the effect of varying TZ concentrations. The model indicated that TZ-binding introduces a bypass pathway that accelerates product release. At low concentrations, TZ binding circumvents slow product release and increases the rate of enzymatic phosphotransfer. However, at high concentrations, TZ inhibits PGK1 activity. The model explains stimulation of enzyme activity by a competitive inhibitor and the biphasic dose-response relationship for TZ and PGK1 activity. By providing a plausible mechanism for interactions between TZ and PGK1, these findings may aid development of TZ or other agents as potential therapeutics for neurodegenerative diseases. The results may also have implications for agents that interact with the active site of other enzymes.
Collapse
|
2
|
Evaluating the psychometric properties of the Fear of Food Measure in adolescents across three independent samples. Psychol Assess 2023; 35:751-762. [PMID: 37410400 DOI: 10.1037/pas0001260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
The Fear of Food Measure (FOFM) was developed to assess eating-related anxiety and evaluate outcomes of food exposure treatment. The FOFM scores in adult community and clinical samples have demonstrated good factor structure, reliability, and validity, but the FOFM has yet to be evaluated in adolescents, despite eating disorders (EDs) being extremely prevalent during adolescence. The current research evaluated the psychometric properties of the FOFM in three independent child and adolescent samples ages 11-18: patients at two separate intensive treatment programs for EDs (N = 688, N = 151) and students in an all-girl high school (N = 310). The revised adolescent version of FOFM (FOFM-A) consists of 10 items and three subscales: Anxiety About Eating, Food Anxiety Rules, and Social Eating Anxiety. We also found support for the use of a global FOFM-A score in an adolescent population. The FOFM-A scores evidenced good internal consistency as well as convergent, discriminant, and incremental validity across all samples. FOFM-A subscales strongly correlated with other measures of ED symptoms and moderately to strongly correlated with measures of anxiety and depression. Adolescents diagnosed with EDs scored significantly higher on all subscales of FOFM-A compared to a community high school sample without ED diagnoses. We identified that a total FOFM-A cutoff score of 1.93 best differentiates between those with and without ED diagnoses. The FOFM-A may be useful in the assessment and treatment of eating-related anxiety and avoidance in adolescents. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
Collapse
|
3
|
Composition of gastrointestinal microbiota in association with treatment response in individuals with metastatic castrate resistant prostate cancer progressing on enzalutamide and initiating treatment with anti-PD-1 (pembrolizumab). Neoplasia 2022; 32:100822. [PMID: 35908379 PMCID: PMC9340532 DOI: 10.1016/j.neo.2022.100822] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/10/2022] [Accepted: 07/11/2022] [Indexed: 01/04/2023]
Abstract
Recent studies in cancer patients and animal models demonstrate that intestinal microbiota influence the therapeutic efficacy of cancer treatments, including immune checkpoint inhibition. However, no studies to-date have investigated relationships between gastrointestinal microbiota composition and response to checkpoint inhibition in advanced metastatic castrate resistant prostate cancer (mCRPC). We performed 16S rRNA gene sequencing of fecal DNA from 23 individuals with mCRPC progressing on enzalutamide and just prior to treatment with anti-PD-1 (pembrolizumab) to determine whether certain features of the microbiome are associated with treatment response (defined as serum PSA decrease >50% at any time on treatment or radiographic response per RECIST V.1.1). Global bacterial composition was similar between responders and non-responders, as assessed by multiple alpha and beta diversity metrics. However, certain bacterial taxa identified by sequencing across multiple 16S rRNA hypervariable regions were consistently associated with response, including the archetypal oral bacterium Streptococcus salivarius. Quantitative PCR (qPCR) of DNA extracts from fecal samples confirmed increased Streptococcus salivarius fecal levels in responders, whereas qPCR of oral swish DNA extracts showed no relationship between oral Streptococcus salivarius levels and response status. Contrary to previous reports in other cancer types, Akkermansia muciniphila levels were reduced in responder samples as assessed by both 16S rRNA sequencing and qPCR. We further analyzed our data in the context of a previously published “integrated index” describing bacteria associated with response and non-response to checkpoint inhibition. We found that the index was not reflective of response status in our cohort. Lastly, we demonstrate little change in the microbiome over time, and with pembrolizumab treatment. Our results suggest that the association between fecal microbiota and treatment response to immunotherapy may be unique to cancer type and/or previous treatment history.
Collapse
|
4
|
Incorporation of Data From Multiple Hypervariable Regions when Analyzing Bacterial 16S rRNA Gene Sequencing Data. Front Genet 2022; 13:799615. [PMID: 35432480 PMCID: PMC9009396 DOI: 10.3389/fgene.2022.799615] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 03/08/2022] [Indexed: 01/04/2023] Open
Abstract
Short read 16 S rRNA amplicon sequencing is a common technique used in microbiome research. However, inaccuracies in estimated bacterial community composition can occur due to amplification bias of the targeted hypervariable region. A potential solution is to sequence and assess multiple hypervariable regions in tandem, yet there is currently no consensus as to the appropriate method for analyzing this data. Additionally, there are many sequence analysis resources for data produced from the Illumina platform, but fewer open-source options available for data from the Ion Torrent platform. Herein, we present an analysis pipeline using open-source analysis platforms that integrates data from multiple hypervariable regions and is compatible with data produced from the Ion Torrent platform. We used the ThermoFisher Ion 16 S Metagenomics Kit and a mock community of twenty bacterial strains to assess taxonomic classification of six amplicons from separate hypervariable regions (V2, V3, V4, V6-7, V8, V9) using our analysis pipeline. We report that different amplicons have different specificities for taxonomic classification, which also has implications for global level analyses such as alpha and beta diversity. Finally, we utilize a generalized linear modeling approach to statistically integrate the results from multiple hypervariable regions and apply this methodology to data from a representative clinical cohort. We conclude that examining sequencing results across multiple hypervariable regions provides more taxonomic information than sequencing across a single region. The data across multiple hypervariable regions can be combined using generalized linear models to enhance the statistical evaluation of overall differences in community structure and relatedness among sample groups.
Collapse
|
5
|
A pilot to assess target engagement of terazosin in Parkinson's disease. Parkinsonism Relat Disord 2022; 94:79-83. [PMID: 34894470 PMCID: PMC8862665 DOI: 10.1016/j.parkreldis.2021.11.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/12/2021] [Accepted: 11/21/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND Impaired brain energy metabolism is a key feature of Parkinson's disease (PD). Terazosin (TZ) binds phosphoglycerate kinase 1 and stimulates its activity, which enhances glycolysis and increases ATP levels. Preclinical and epidemiologic data suggest that TZ may be neuroprotective in PD. We aimed to assess target engagement and safety of TZ in people with PD. METHODS We performed a 12-week pilot study in people with PD. Participants were randomized to receive 5 mg TZ or placebo. Participants and study personnel were blinded. We assessed TZ target engagement by measuring brain ATP with 31P-magnetic resonance spectroscopy (MRS) and whole blood ATP with a luminescence assay. Robust linear regression models compared changes between groups controlling for baseline brain and blood ATP levels, respectively. We also assessed clinical measures of PD and adverse events. RESULTS Thirteen participants were randomized. Mild dizziness/lightheadedness was more common in the TZ group, and three participants taking TZ dropped out because of dizziness and/or orthostatic hypotension. Compared to the placebo group, the TZ group had a significant increase in the ratio of βATP to inorganic phosphate in the brain. The TZ group also had a significant increase in blood ATP levels compared to the placebo group (p < 0.01). CONCLUSIONS This pilot study suggests that TZ may engage its target and change ATP levels in the brain and blood of people with PD. Further studies may be warranted to test the disease-modifying potential of TZ.
Collapse
|
6
|
Selenium and the 15kDa Selenoprotein Impact Colorectal Tumorigenesis by Modulating Intestinal Barrier Integrity. Int J Mol Sci 2021; 22:10651. [PMID: 34638991 PMCID: PMC8508755 DOI: 10.3390/ijms221910651] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 09/26/2021] [Accepted: 09/30/2021] [Indexed: 01/19/2023] Open
Abstract
Selenoproteins play important roles in many cellular functions and biochemical pathways in mammals. Our previous study showed that the deficiency of the 15 kDa selenoprotein (Selenof) significantly reduced the formation of aberrant crypt foci (ACF) in a mouse model of azoxymethane (AOM)-induced colon carcinogenesis. The objective of this study was to examine the effects of Selenof on inflammatory tumorigenesis, and whether dietary selenium modified these effects. For 20 weeks post-weaning, Selenof-knockout (KO) mice and littermate controls were fed diets that were either deficient, adequate or high in sodium selenite. Colon tumors were induced with AOM and dextran sulfate sodium. Surprisingly, KO mice had drastically fewer ACF but developed a similar number of tumors as their littermate controls. Expression of genes important in inflammatory colorectal cancer and those relevant to epithelial barrier function was assessed, in addition to structural differences via tissue histology. Our findings point to Selenof's potential role in intestinal barrier integrity and structural changes in glandular and mucin-producing goblet cells in the mucosa and submucosa, which may determine the type of tumor developing.
Collapse
|
7
|
A network investigation of core symptoms and pathways across duration of illness using a comprehensive cognitive-behavioral model of eating-disorder symptoms. Psychol Med 2021; 51:815-824. [PMID: 31907093 DOI: 10.1017/s0033291719003817] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND In the past decade, network analysis (NA) has been applied to psychopathology to quantify complex symptom relationships. This statistical technique has demonstrated much promise, as it provides researchers the ability to identify relationships across many symptoms in one model and can identify central symptoms that may predict important clinical outcomes. However, network models are highly influenced by node selection, which could limit the generalizability of findings. The current study (N = 6850) tests a comprehensive, cognitive-behavioral model of eating-disorder symptoms using items from two, widely used measures (Eating Disorder Examination Questionnaire and Eating Pathology Symptoms Inventory). METHODS We used NA to identify central symptoms and compared networks across the duration of illness (DOI), as chronicity is one of the only known predictors of poor outcome in eating disorders (EDs). RESULTS Our results suggest that eating when not hungry and feeling fat were the most central symptoms across groups. There were no significant differences in network structure across DOI, meaning the connections between symptoms remained relatively consistent. However, differences emerged in central symptoms, such that cognitive symptoms related to overvaluation of weight/shape were central in individuals with shorter DOI, and behavioral central symptoms emerged more in medium and long DOI. CONCLUSIONS Our results have important implications for the treatment of individuals with enduring EDs, as they may have a different core, maintaining symptoms. Additionally, our findings highlight the importance of using comprehensive, theoretically- or empirically-derived models for NA.
Collapse
|
8
|
Early pathogenesis of cystic fibrosis gallbladder disease in a porcine model. J Transl Med 2020; 100:1388-1399. [PMID: 32719544 PMCID: PMC7578062 DOI: 10.1038/s41374-020-0474-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 12/13/2022] Open
Abstract
Hepatobiliary disease causes significant morbidity in people with cystic fibrosis (CF), yet this problem remains understudied. We previously found that newborn CF pigs have microgallbladders with significant luminal obstruction in the absence of infection and consistent inflammation. In this study, we sought to better understand the early pathogenesis of CF pig gallbladder disease. We hypothesized that loss of CFTR would impair gallbladder epithelium anion/liquid secretion and increase mucin production. CFTR was expressed apically in non-CF pig gallbladder epithelium but was absent in CF. CF pig gallbladders lacked cAMP-stimulated anion transport. Using a novel gallbladder epithelial organoid model, we found that Cl- or HCO3- was sufficient for non-CF organoid swelling. This response was absent for non-CF organoids in Cl-/HCO3--free conditions and in CF. Single-cell RNA-sequencing revealed a single epithelial cell type in non-CF gallbladders that coexpressed CFTR, MUC5AC, and MUC5B. Despite CF gallbladders having increased luminal MUC5AC and MUC5B accumulation, there was no significant difference in the epithelial expression of gel-forming mucins between non-CF and CF pig gallbladders. In conclusion, these data suggest that loss of CFTR-mediated anion transport and fluid secretion contribute to microgallbladder development and luminal mucus accumulation in CF.
Collapse
|
9
|
Inflammation-associated pathologies in a case of prostate schistosomiasis: Implications for a causal role in prostate carcinogenesis. Prostate 2019; 79:1316-1325. [PMID: 31212384 DOI: 10.1002/pros.23841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 05/07/2019] [Indexed: 11/12/2022]
Abstract
BACKGROUND Urogenital infection with Schistosoma haematobium is a risk factor for the development of squamous cell carcinoma of the urinary bladder. The pathophysiology is thought to be mediated in part by inflammation, cellular damage, and bladder regeneration induced by the parasitic infection. Herein, we report an unusual case of schistosomiasis of the prostate that was found concurrent with prostate adenocarcinoma in a radical prostatectomy specimen from a man in the United States. METHODS The infecting Schistosoma species was characterized via histomorphology and acid-fast stain. The concurrent Gleason score 6 prostate cancer was assessed for ETS transcription factor ERG (ERG), phosphatase and tensin homolog (PTEN), p27, and p53 status using immunohistochemistry (IHC). Cellular proliferation and the presence of intermediate cells in prostatic atrophy were assessed via immunostaining for Ki67 and CK903, respectively. RESULTS Histomorphology and acid-fast stain of the infecting species were consistent with S. haematobium. We classified the Gleason score 6 prostate adenocarcinoma via IHC as ERG positive, PTEN intact, p27 intact, and without p53 nuclear accumulation. The prostatic epithelium immediately adjacent to the schistosomiasis-related granulomatous inflammation was atrophic and accompanied by increased cellular proliferation and the presence of intermediate cells. Upon literature review, we determined that prostate schistosomiasis is associated with a young age of prostate cancer diagnosis and highly aggressive prostate cancer. CONCLUSIONS This is a rare case of prostate schistosomiasis in the United States; however, prostate schistosomiasis occurs frequently in endemic areas. The patient had traveled to a Schistosoma-endemic region, which was the likely location of exposure to the parasite. To our knowledge, this is the first report of the association of proliferative inflammatory atrophy and intermediate cells with schistosomiasis of the prostate. We propose that prostate schistosomiasis may be considered as a risk factor for the development of prostate cancer in geographic regions where Schistosoma species are endemic.
Collapse
|
10
|
Abstract 129: Biobanking and feasibility considerations for prostate cancer gastrointestinal microbiome studies. Cancer Res 2018. [DOI: 10.1158/1538-7445.am2018-129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The human microbiome may play a role in prostate health and disease as both direct and indirect interactions. Direct interactions between microbiota and prostate cancer include prostate infections, inflammation, prostatitis, and potentially interactions with the urinary microbiome. Indirectly, the gastrointestinal (GI) microbiota may influence prostate cancer via xenobiotic metabolism, augmentation of treatment response, and contributions to systemic inflammation and cytokines. In the present study, we are seeking to understand how different prostate cancer treatments may be affected by the microbial composition of the GI tract. We are currently developing a biorepository of fecal specimens from prostate cancer patients in different clinical states of disease. A key question during the planning phase of this biorepository was if samples can be collected and banked in the form of a rectal swab, instead of the more traditional method of a stool sample. Rectal swabs provide an advantage over collection of stool specimens in that they are easily collected (the patient can self-collect) in a standardized, “on demand” fashion during routine patient visits. Therefore, a pilot study was undertaken to compare the microbial profile of samples collected via both methods from the same individual. We concomitantly collected both stool samples and rectal swabs from 6 patients undergoing active surveillance for prostate cancer at the Johns Hopkins Hospital. All samples were stored at -80°C until we were ready to isolate bacterial DNA. DNA was extracted with a phenol:chloroform based protocol that we have optimized for microbiome studies that includes multiple enzyme digest and bead beating. We conducted Illumina amplicon sequencing of PCR products amplified with universal primers designed against the V6 hypervariable region of the bacterial 16S rRNA gene. We tested our sequencing strategy against Microbiome Reference Standards obtained from American Type Culture Collection (ATCC). The results of our analysis from prostate cancer patients indicated high similarity of bacterial profiles obtained for matched stool and swabs in 4 of the 6 patients. In both of the cases that were dissimilar, there was a greater representation of Enterobacteriaceae in the stool sample versus the swab. We conclude that collection of rectal swabs is a more feasible and convenient means of sampling the GI microbiota in prostate cancer patients, especially when aiming to conduct longitudinal studies with multiple sample collections to correlate microbiota profiles to treatments and/or treatment response. Due to the differences that were identified, we recommend deciding on the sample collection method at the onset of biobanking, and keeping the sampling method consistent throughout.
Citation Format: Sarah E. Ernst, Mark C. Markowski, Anuj Gupta, Sarah J. Wheelan, H. Ballentine Carter, Alan W. Partin, Cynthia L. Sears, Karen S. Sfanos. Biobanking and feasibility considerations for prostate cancer gastrointestinal microbiome studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 129.
Collapse
|
11
|
Lack of cystic fibrosis transmembrane conductance regulator disrupts fetal airway development in pigs. J Transl Med 2018; 98:825-838. [PMID: 29467455 PMCID: PMC6019641 DOI: 10.1038/s41374-018-0026-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/16/2017] [Accepted: 01/10/2018] [Indexed: 11/15/2022] Open
Abstract
Loss of cystic fibrosis transmembrane conductance regulator (CFTR) function causes cystic fibrosis (CF), predisposing the lungs to chronic infection and inflammation. In young infants with CF, structural airway defects are increasingly recognized before the onset of significant lung disease, which suggests a developmental origin and a possible role in lung disease pathogenesis. The role(s) of CFTR in lung development is unclear and developmental studies in humans with CF are not feasible. Young CF pigs have structural airway changes and develop spontaneous postnatal lung disease similar to humans; therefore, we studied lung development in the pig model (non-CF and CF). CF trachea and proximal airways had structural lesions detectable as early as pseudoglandular development. At this early developmental stage, budding CF airways had smaller, hypo-distended lumens compared to non-CF airways. Non-CF lung explants exhibited airway lumen distension in response to forskolin/IBMX as well as to fibroblast growth factor (FGF)-10, consistent with CFTR-dependent anion transport/secretion, but this was lacking in CF airways. We studied primary pig airway epithelial cell cultures and found that FGF10 increased cellular proliferation (non-CF and CF) and CFTR expression/function (in non-CF only). In pseudoglandular stage lung tissue, CFTR protein was exclusively localized to the leading edges of budding airways in non-CF (but not CF) lungs. This discreet microanatomic localization of CFTR is consistent with the site, during branching morphogenesis, where airway epithelia are responsive to FGF10 regulation. In summary, our results suggest that the CF proximal airway defects originate during branching morphogenesis and that the lack of CFTR-dependent anion transport/liquid secretion likely contributes to these hypo-distended airways.
Collapse
|
12
|
Airway acidification initiates host defense abnormalities in cystic fibrosis mice. Science 2016; 351:503-7. [PMID: 26823428 DOI: 10.1126/science.aad5589] [Citation(s) in RCA: 221] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cystic fibrosis (CF) is caused by mutations in the gene that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. In humans and pigs, the loss of CFTR impairs respiratory host defenses, causing airway infection. But CF mice are spared. We found that in all three species, CFTR secreted bicarbonate into airway surface liquid. In humans and pigs lacking CFTR, unchecked H(+) secretion by the nongastric H(+)/K(+) adenosine triphosphatase (ATP12A) acidified airway surface liquid, which impaired airway host defenses. In contrast, mouse airways expressed little ATP12A and secreted minimal H(+); consequently, airway surface liquid in CF and non-CF mice had similar pH. Inhibiting ATP12A reversed host defense abnormalities in human and pig airways. Conversely, expressing ATP12A in CF mouse airways acidified airway surface liquid, impaired defenses, and increased airway bacteria. These findings help explain why CF mice are protected from infection and nominate ATP12A as a potential therapeutic target for CF.
Collapse
|
13
|
Mutating the Conserved Q-loop Glutamine 1291 Selectively Disrupts Adenylate Kinase-dependent Channel Gating of the ATP-binding Cassette (ABC) Adenylate Kinase Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and Reduces Channel Function in Primary Human Airway Epithelia. J Biol Chem 2015; 290:14140-53. [PMID: 25887396 PMCID: PMC4447984 DOI: 10.1074/jbc.m114.611616] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Indexed: 11/06/2022] Open
Abstract
The ATP-binding cassette (ABC) transporter cystic fibrosis transmembrane conductance regulator (CFTR) and two other non-membrane-bound ABC proteins, Rad50 and a structural maintenance of chromosome (SMC) protein, exhibit adenylate kinase activity in the presence of physiologic concentrations of ATP and AMP or ADP (ATP + AMP ⇆ 2 ADP). The crystal structure of the nucleotide-binding domain of an SMC protein in complex with the adenylate kinase bisubstrate inhibitor P(1),P(5)-di(adenosine-5') pentaphosphate (Ap5A) suggests that AMP binds to the conserved Q-loop glutamine during the adenylate kinase reaction. Therefore, we hypothesized that mutating the corresponding residue in CFTR, Gln-1291, selectively disrupts adenylate kinase-dependent channel gating at physiologic nucleotide concentrations. We found that substituting Gln-1291 with bulky side-chain amino acids abolished the effects of Ap5A, AMP, and adenosine 5'-monophosphoramidate on CFTR channel function. 8-Azidoadenosine 5'-monophosphate photolabeling of the AMP-binding site and adenylate kinase activity were disrupted in Q1291F CFTR. The Gln-1291 mutations did not alter the potency of ATP at stimulating current or ATP-dependent gating when ATP was the only nucleotide present. However, when physiologic concentrations of ADP and AMP were added, adenylate kinase-deficient Q1291F channels opened significantly less than wild type. Consistent with this result, we found that Q1291F CFTR displayed significantly reduced Cl(-) channel function in well differentiated primary human airway epithelia. These results indicate that a highly conserved residue of an ABC transporter plays an important role in adenylate kinase-dependent CFTR gating. Furthermore, the results suggest that adenylate kinase activity is important for normal CFTR channel function in airway epithelia.
Collapse
|
14
|
Medical reversal of chronic sinusitis in a cystic fibrosis patient with ivacaftor. Int Forum Allergy Rhinol 2014; 5:178-81. [PMID: 25363320 DOI: 10.1002/alr.21440] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 09/17/2014] [Accepted: 09/25/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Chronic sinusitis is universal in cystic fibrosis (CF) and our current treatments are ineffective in reversing sinus disease. The objective of this work was to determine if increasing CF transmembrane conductance regulator (CFTR) activity by ivacaftor could treat CF sinus disease and assess its effect on primary sinus epithelial cultures. METHODS Case report of 1 patient with long-standing chronic sinus disease and a new diagnosis of CF with a mild mutation (P205S) and a severe mutation (G551D). We discuss clinical changes in symptoms, radiographic findings, nasal potential difference testing, and nasal pH values before and after treatment with ivacaftor. We then developed primary sinonasal epithelial cell cultures from a biopsy of the patient to determine changes in airway surface liquid (ASL) pH and ASL viscosity after ivacaftor treatment. RESULTS Ivacaftor treatment reversed CT findings of CF sinus disease, increased nasal voltage and pH, and resolved sinus symptoms after 10 months of therapy. Ivacaftor significantly increased ASL pH and decreased ASL viscosity in primary airway cultures. CONCLUSION This report documents the reversal of CF sinus disease. Based on our in vivo and in vitro results, we speculate that ivacaftor may reverse CF sinusitis by increasing ASL pH and decreasing ASL viscosity. These studies suggest that CFTR modulation may be effective in treating CF and perhaps non-CF sinusitis.
Collapse
|
15
|
Integrin α6β4 identifies human distal lung epithelial progenitor cells with potential as a cell-based therapy for cystic fibrosis lung disease. PLoS One 2013; 8:e83624. [PMID: 24349537 PMCID: PMC3861522 DOI: 10.1371/journal.pone.0083624] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 11/10/2013] [Indexed: 12/21/2022] Open
Abstract
To develop stem/progenitor cell-based therapy for cystic fibrosis (CF) lung disease, it is first necessary to identify markers of human lung epithelial progenitor/stem cells and to better understand the potential for differentiation into distinct lineages. Here we investigated integrin α6β4 as an epithelial progenitor cell marker in the human distal lung. We identified a subpopulation of α6β4+ cells that localized in distal small airways and alveolar walls and were devoid of pro-surfactant protein C expression. The α6β4+ epithelial cells demonstrated key properties of stem cells ex vivo as compared to α6β4- epithelial cells, including higher colony forming efficiency, expression of stem cell-specific transcription factor Nanog, and the potential to differentiate into multiple distinct lineages including basal and Clara cells. Co-culture of α6β4+ epithelial cells with endothelial cells enhanced proliferation. We identified a subset of adeno-associated virus (AAVs) serotypes, AAV2 and AAV8, capable of transducing α6β4+ cells. In addition, reconstitution of bronchi epithelial cells from CF patients with only 5% normal α6β4+ epithelial cells significantly rescued defects in Cl- transport. Therefore, targeting the α6β4+ epithelial population via either gene delivery or progenitor cell-based reconstitution represents a potential new strategy to treat CF lung disease.
Collapse
|
16
|
Intestinal CFTR expression alleviates meconium ileus in cystic fibrosis pigs. J Clin Invest 2013; 123:2685-93. [PMID: 23676501 DOI: 10.1172/jci68867] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 03/07/2013] [Indexed: 12/20/2022] Open
Abstract
Cystic fibrosis (CF) pigs develop disease with features remarkably similar to those in people with CF, including exocrine pancreatic destruction, focal biliary cirrhosis, micro-gallbladder, vas deferens loss, airway disease, and meconium ileus. Whereas meconium ileus occurs in 15% of babies with CF, the penetrance is 100% in newborn CF pigs. We hypothesized that transgenic expression of porcine CF transmembrane conductance regulator (pCFTR) cDNA under control of the intestinal fatty acid-binding protein (iFABP) promoter would alleviate the meconium ileus. We produced 5 CFTR-/-;TgFABP>pCFTR lines. In 3 lines, intestinal expression of CFTR at least partially restored CFTR-mediated anion transport and improved the intestinal phenotype. In contrast, these pigs still had pancreatic destruction, liver disease, and reduced weight gain, and within weeks of birth, they developed sinus and lung disease, the severity of which varied over time. These data indicate that expressing CFTR in intestine without pancreatic or hepatic correction is sufficient to rescue meconium ileus. Comparing CFTR expression in different lines revealed that approximately 20% of wild-type CFTR mRNA largely prevented meconium ileus. This model may be of value for understanding CF pathophysiology and testing new preventions and therapies.
Collapse
|
17
|
CFTR is required for maximal transepithelial liquid transport in pig alveolar epithelia. Am J Physiol Lung Cell Mol Physiol 2012; 303:L152-60. [PMID: 22637155 DOI: 10.1152/ajplung.00116.2012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A balance between alveolar liquid absorption and secretion is critical for maintaining optimal alveolar subphase liquid height and facilitating gas exchange in the alveolar space. However, the role of cystic fibrosis transmembrane regulator protein (CFTR) in this homeostatic process has remained elusive. Using a newly developed porcine model of cystic fibrosis, in which CFTR is absent, we investigated ion transport properties and alveolar liquid transport in isolated type II alveolar epithelial cells (T2AECs) cultured at the air-liquid interface. CFTR was distributed exclusively to the apical surface of cultured T2AECs. Alveolar epithelia from CFTR(-/-) pigs failed to increase liquid absorption in response to agents that increase cAMP, whereas cAMP-stimulated liquid absorption in CFTR(+/-) epithelia was similar to that in CFTR(+/+) epithelia. Expression of recombinant CFTR restored stimulated liquid absorption in CFTR(-/-) T2AECs but had no effect on CFTR(+/+) epithelia. In ex vivo studies of nonperfused lungs, stimulated liquid absorption was defective in CFTR(-/-) alveolar epithelia but similar between CFTR(+/+) and CFTR(+/-) epithelia. When epithelia were studied at the air-liquid interface, elevating cAMP levels increased subphase liquid height in CFTR(+/+) but not in CFTR(-/-) T2AECs. Our findings demonstrate that CFTR is required for maximal liquid absorption under cAMP stimulation, but it is not the rate-limiting factor. Furthermore, our data define a role for CFTR in liquid secretion by T2AECs. These insights may help to develop new treatment strategies for pulmonary edema and respiratory distress syndrome, diseases in which lung liquid transport is disrupted.
Collapse
|
18
|
Abstract
Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. The most common CF-associated mutation is ΔF508, which deletes a phenylalanine in position 508. In vitro studies indicate that the resultant protein, CFTR-ΔF508, is misprocessed, although the in vivo consequences of this mutation remain uncertain. To better understand the effects of the ΔF508 mutation in vivo, we produced CFTR(ΔF508/ΔF508) pigs. Our biochemical, immunocytochemical, and electrophysiological data on CFTR-ΔF508 in newborn pigs paralleled in vitro predictions. They also indicated that CFTR(ΔF508/ΔF508) airway epithelia retain a small residual CFTR conductance, with maximal stimulation producing ~6% of wild-type function. Cyclic adenosine 3',5'-monophosphate (cAMP) agonists were less potent at stimulating current in CFTR(Δ)(F508/)(Δ)(F508) epithelia, suggesting that quantitative tests of maximal anion current may overestimate transport under physiological conditions. Despite residual CFTR function, four older CFTR(ΔF508/ΔF508) pigs developed lung disease similar to human CF. These results suggest that this limited CFTR activity is insufficient to prevent lung or gastrointestinal disease in CF pigs. These data also suggest that studies of recombinant CFTR-ΔF508 misprocessing predict in vivo behavior, which validates its use in biochemical and drug discovery experiments. These findings help elucidate the molecular pathogenesis of the common CF mutation and will guide strategies for developing new therapeutics.
Collapse
|
19
|
Glucose depletion in the airway surface liquid is essential for sterility of the airways. PLoS One 2011; 6:e16166. [PMID: 21311590 PMCID: PMC3029092 DOI: 10.1371/journal.pone.0016166] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 12/08/2010] [Indexed: 11/19/2022] Open
Abstract
Diabetes mellitus predisposes the host to bacterial infections. Moreover, hyperglycemia has been shown to be an independent risk factor for respiratory infections. The luminal surface of airway epithelia is covered by a thin layer of airway surface liquid (ASL) and is normally sterile despite constant exposure to bacteria. The balance between bacterial growth and killing in the airway determines the outcome of exposure to inhaled or aspirated bacteria: infection or sterility. We hypothesized that restriction of carbon sources--including glucose--in the ASL is required for sterility of the lungs. We found that airway epithelia deplete glucose from the ASL via a novel mechanism involving polarized expression of GLUT-1 and GLUT-10, intracellular glucose phosphorylation, and low relative paracellular glucose permeability in well-differentiated cultures of human airway epithelia and in segments of airway epithelia excised from human tracheas. Moreover, we found that increased glucose concentration in the ASL augments growth of P. aeruginosa in vitro and in the lungs of hyperglycemic ob/ob and db/db mice in vivo. In contrast, hyperglycemia had no effect on intrapulmonary bacterial growth of a P. aeruginosa mutant that is unable to utilize glucose as a carbon source. Our data suggest that depletion of glucose in the airway epithelial surface is a novel mechanism for innate immunity. This mechanism is important for sterility of the airways and has implications in hyperglycemia and conditions that result in disruption of the epithelial barrier in the lung.
Collapse
|
20
|
Loss of anion transport without increased sodium absorption characterizes newborn porcine cystic fibrosis airway epithelia. Cell 2011; 143:911-23. [PMID: 21145458 DOI: 10.1016/j.cell.2010.11.029] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 08/31/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
Abstract
Defective transepithelial electrolyte transport is thought to initiate cystic fibrosis (CF) lung disease. Yet, how loss of CFTR affects electrolyte transport remains uncertain. CFTR⁻(/)⁻ pigs spontaneously develop lung disease resembling human CF. At birth, their airways exhibit a bacterial host defense defect, but are not inflamed. Therefore, we studied ion transport in newborn nasal and tracheal/bronchial epithelia in tissues, cultures, and in vivo. CFTR⁻(/)⁻ epithelia showed markedly reduced Cl⁻ and HCO₃⁻ transport. However, in contrast to a widely held view, lack of CFTR did not increase transepithelial Na(+) or liquid absorption or reduce periciliary liquid depth. Like human CF, CFTR⁻(/)⁻ pigs showed increased amiloride-sensitive voltage and current, but lack of apical Cl⁻ conductance caused the change, not increased Na(+) transport. These results indicate that CFTR provides the predominant transcellular pathway for Cl⁻ and HCO₃⁻ in porcine airway epithelia, and reduced anion permeability may initiate CF airway disease.
Collapse
|
21
|
Boophilus annulatus and B. microplus: laboratory tests of insecticides. JOURNAL OF ECONOMIC ENTOMOLOGY 1973; 66:130-133. [PMID: 4690254 DOI: 10.1093/jee/66.1.130] [Citation(s) in RCA: 339] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
|
22
|
Laboratory testing of insecticides for control of the winter tick. JOURNAL OF ECONOMIC ENTOMOLOGY 1971; 64:686-688. [PMID: 5558278 DOI: 10.1093/jee/64.3.686] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
23
|
Small-scale field tests with dermally applied animal systemic insecticides for control of the common cattle grub. JOURNAL OF ECONOMIC ENTOMOLOGY 1970; 63:1233-1237. [PMID: 5475204 DOI: 10.1093/jee/63.4.1233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
24
|
Laboratory study of Anocentor nitens (Neumann) (Acarina: Ixodidae), the tropical horse tick. JOURNAL OF MEDICAL ENTOMOLOGY 1969; 6:150-154. [PMID: 5807854 DOI: 10.1093/jmedent/6.2.150] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
25
|
Insecticides for control of the cattle tick and the southern cattle tick on cattle. JOURNAL OF ECONOMIC ENTOMOLOGY 1968; 61:467-470. [PMID: 5642113 DOI: 10.1093/jee/61.2.467] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
26
|
Control of the lone star tick on cattle. JOURNAL OF ECONOMIC ENTOMOLOGY 1967; 60:1736-1738. [PMID: 6081042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|