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Dorfman CS, Shelby RA, Stalls JM, Somers TJ, Keefe FJ, Vilardaga JP, Winger JG, Mitchell K, Ehren C, Oeffinger KC. Improving Symptom Management for Survivors of Young Adult Cancer: Development of a Novel Intervention. J Adolesc Young Adult Oncol 2023; 12:472-487. [PMID: 36178972 PMCID: PMC10457621 DOI: 10.1089/jayao.2022.0100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Purpose: Improved symptom management is a critical although unmet post-treatment need for young adult (YA) cancer survivors (aged 18-39 at diagnosis). This study aimed to develop and refine a behavioral symptom management intervention for YA survivors. Methods: Phase I: YA survivors (N = 21) and oncology providers (N = 11) completed individual interviews and an online, self-report assessment to examine symptom experiences, the need for a behavioral symptom management intervention for YAs, and perceptions about potential intervention components, structure, and format. Phase II: YA survivors (N = 10) completed user testing sessions, providing feedback on the prototype intervention materials (paper manual and mobile application), and completed an online assessment. Quantitative data were examined using descriptive statistics. Rapid qualitative analysis, a methodologically rigorous standardized approach, was used. Results: Pain, fatigue, and distress were ranked as top concerns by most YAs and providers. Phase I interviews underscored the need for a symptom management intervention for YAs. YAs and providers highlighted potential coping strategies and program format/structure suggestions (e.g., small group format) to best meet YAs' needs. A prototype intervention was developed combining the following: traditional behavioral symptom coping skills; home-based physical activity; strategies from Acceptance and Commitment Therapy and Meaning-Centered Psychotherapy; and strategies to foster self-compassion. Phase II user testing sessions highlighted strengths and suggestions for refining the prototype materials. Conclusion: Post-treatment symptoms are common for YAs. A tailored behavioral symptom management program was developed and refined with input from YAs and providers and will be examined for feasibility and acceptability in a pilot randomized controlled trial. Clinical Trial: Clinicaltrials.gov identifier NCT04035447.
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Affiliation(s)
- Caroline S. Dorfman
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Rebecca A. Shelby
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Juliann M. Stalls
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Tamara J. Somers
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Francis J. Keefe
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Jennifer Plumb Vilardaga
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA
| | - Joseph G. Winger
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA
| | - Kara Mitchell
- Duke Health and Fitness Center, Duke University Medical Center, Durham, North Carolina, USA
| | - Christopher Ehren
- Duke Health and Fitness Center, Duke University Medical Center, Durham, North Carolina, USA
| | - Kevin C. Oeffinger
- Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina, USA
- Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
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Cook CE, Bailliard A, Bent JA, Bialosky JE, Carlino E, Colloca L, Esteves JE, Newell D, Palese A, Reed WR, Vilardaga JP, Rossettini G. An international consensus definition for contextual factors: findings from a nominal group technique. Front Psychol 2023; 14:1178560. [PMID: 37465492 PMCID: PMC10351924 DOI: 10.3389/fpsyg.2023.1178560] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/07/2023] [Indexed: 07/20/2023] Open
Abstract
Objective Emerging literature suggests contextual factors are important components of therapeutic encounters and may substantially influence clinical outcomes of a treatment intervention. At present, a single consensus definition of contextual factors, which is universal across all health-related conditions is lacking. The objective of this study was to create a consensus definition of contextual factors to better refine this concept for clinicians and researchers. Design The study used a multi-stage virtual Nominal Group Technique (vNGT) to create and rank contextual factor definitions. Nominal group techniques are a form of consensus-based research, and are beneficial for identifying problems, exploring solutions and establishing priorities. Setting International. Main outcome measures The initial stages of the vNGT resulted in the creation of 14 independent contextual factor definitions. After a prolonged discussion period, the initial definitions were heavily modified, and 12 final definitions were rank ordered by the vNGT participants from first to last. Participants The 10 international vNGT participants had a variety of clinical backgrounds and research specializations and were all specialists in contextual factors research. Results A sixth round was used to identify a final consensus, which reflected the complexity of contextual factors and included three primary domains: (1) an overall definition; (2) qualifiers that serve as examples of the key areas of the definition; and (3) how contextual factors may influence clinical outcomes. Conclusion Our consensus definition of contextual factors seeks to improve the understanding and communication between clinicians and researchers. These are especially important in recognizing their potential role in moderating and/or mediating clinical outcomes.
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Affiliation(s)
- Chad E. Cook
- Department of Orthopaedics, Duke University, Durham, NC, United States
- Department of Population Health Sciences, Duke University, Durham, NC, United States
- Duke Clinical Research Institute, Duke University, Durham, NC, United States
| | - Antoine Bailliard
- Department of Orthopaedics, Duke University, Durham, NC, United States
- Occupational Therapy Doctorate Division, Duke University, Durham, NC, United States
| | - Jennifer A. Bent
- Department of Rehabilitation, Duke University Hospital System, Durham, NC, United States
| | - Joel E. Bialosky
- Department of Physical Therapy, University of Florida, Gainesville, FL, United States
- Brooks-PHHP Research Collaboration, Gainesville, FL, United States
| | - Elisa Carlino
- Department of Neuroscience Rita Levi Montalcini, University of Turin, Turin, Italy
| | - Luana Colloca
- Departement of Pain and Translational Symptom Science and the Placebo Beyond Opinions Center, University of Maryland School of Nursing, Baltimore, MD, United States
| | - Jorge E. Esteves
- Clinical-Based Human Research Department, Foundation COME Collaboration, Pescara, Italy
- Malta ICOM Educational, Gżira, Malta
| | - Dave Newell
- Anglo-European College of Chiropractic University College, Bournemouth, United Kingdom
| | - Alvisa Palese
- Department of Medical Sciences, School of Nursing, University of Udine, Udine, Italy
| | - William R. Reed
- Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, AL, United States
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Nagy GA, Cuervo C, Ramos Rodríguez EY, Plumb Vilardaga J, Zerubavel N, West JL, Falick MC, Parra DC. Building a More Diverse and Inclusive Science: Mindfulness-Based Approaches for Latinx Individuals. Mindfulness (N Y) 2022; 13:942-954. [PMID: 35282138 PMCID: PMC8902727 DOI: 10.1007/s12671-022-01846-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/15/2022] [Indexed: 12/29/2022]
Abstract
Objectives This article represents a call to action for the mindfulness field to be more diverse and inclusive of Latinx individuals. Building a diverse and inclusive science around mindfulness-based approaches (MBAs) that considers important group-level cultural and contextual information is an important public health challenge in need of innovative solutions. Methods We describe ways that the Latinx population is poised to benefit from MBAs. We further elucidate challenges, describe potential solutions, and outline a research agenda that may hold promise for building a more inclusive mindfulness movement. Results Our recommendations center around developing nuanced cultural adaptations to MBAs, engaging Latinx individuals in research, increasing the rigor of scientific studies pertaining to Latinx individuals, relying on implementation science to develop innovative methods for disseminating MBAs to Latinx individuals, developing training and certification mechanisms to increase diversity and representation of Latinx mindfulness teachers, and creating mechanisms for the oversight of MBAs within this group. Conclusions There has been a lack of inclusivity of Latinx individuals in the field of MBAs with regards to research studies, barriers to access for economically disadvantaged groups, and lack of diversity in its workforce. Considering the recognition of adverse social drivers of health that generate chronic stress and health disparities, the Latinx population is especially poised to benefit greatly from MBAs. A diverse and inclusive mindfulness science holds promise to enhance the effectiveness, acceptability, feasibility, and wide-scale dissemination and implementation of MBAs.
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Teo I, Vilardaga JP, Tan YP, Winger J, Cheung YB, Yang GM, Finkelstein EA, Shelby RA, Kamal AH, Kimmick G, Somers TJ. A feasible and acceptable multicultural psychosocial intervention targeting symptom management in the context of advanced breast cancer. Psychooncology 2020; 29:389-397. [PMID: 31703146 DOI: 10.1002/pon.5275] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 10/23/2019] [Accepted: 10/27/2019] [Indexed: 02/01/2023]
Abstract
OBJECTIVE Advanced breast cancer patients around the world experience high symptom burden (ie, distress, pain, and fatigue) and are in need of psychosocial interventions that target symptom management. This study examined the feasibility, acceptability, and engagement of a psychosocial intervention that uses cognitive-behavioral strategies along with mindfulness and values-based activity to enhance patients' ability to manage symptoms of advanced disease in a cross-cultural setting (United States and Singapore). Pre-treatment to post-treatment outcomes for distress, pain, and fatigue were compared between intervention recipients and waitlisted controls. METHODS A pilot randomized controlled trial included women with advanced breast cancer (N = 85) that were recruited in the United States and Singapore. Participants either received the four session intervention or be put on waitlist. Descriptive statistics and effect size of symptom change were calculated. RESULTS The psychosocial intervention was found to be feasible as indicated through successful trial accrual, low study attrition (15% ), and high intervention adherence (77% completed all sessions). Acceptability (ie, program satisfaction and cultural sensitivity) and engagement to the study intervention (ie, practice of skills taught) were also high. Anxiety, depression, and fatigue scores remained stable or improved among intervention participants while the same symptoms worsened in the control group. In general, effect sizes are larger in the US sample compared with the Singapore sample. CONCLUSIONS The cognitive-behavioral, mindfulness, and values-based intervention is feasible, acceptable, and engaging for advanced breast cancer patients in a cross-cultural setting and has potential for efficacy. Further larger-scaled study of intervention efficacy is warranted.
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Affiliation(s)
- Irene Teo
- Lien Centre for Palliative Care, Duke-NUS Medical School, Singapore
- National Cancer Centre Singapore, Singapore
| | | | | | - Joseph Winger
- Duke-NUS Medical School School of Medicine, Durham, North Carolina
| | - Yin Bun Cheung
- Programme in Health Services and Systems Research, Duke-NUS Medical School, Singapore
- Centre for Quantitative Medicine, Duke-NUS Medical School, Singapore
- Centre for Child Health Research, Tampere University, Tampere, Finland
| | - Grace Meijuan Yang
- Lien Centre for Palliative Care, Duke-NUS Medical School, Singapore
- National Cancer Centre Singapore, Singapore
| | - Eric A Finkelstein
- Lien Centre for Palliative Care, Duke-NUS Medical School, Singapore
- Programme in Health Services and Systems Research, Duke-NUS Medical School, Singapore
| | - Rebecca A Shelby
- Duke-NUS Medical School School of Medicine, Durham, North Carolina
| | - Arif H Kamal
- Duke-NUS Medical School School of Medicine, Durham, North Carolina
| | - Gretchen Kimmick
- Duke-NUS Medical School School of Medicine, Durham, North Carolina
| | - Tamara J Somers
- Duke-NUS Medical School School of Medicine, Durham, North Carolina
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Abstract
Acceptance and Commitment Therapy (ACT) training often includes experiential elements aimed at improving therapist psychological flexibility, yet the effects of ACT training on therapist psychological flexibility have yet to be evaluated. This pilot study examines the effects of experiential phone consultation as an adjunct to a standard continuing education workshop on psychological flexibility and burnout among therapists learning ACT. In this study, counselors taking a 2-day ACT workshop were randomly assigned to either six 30-min phone consultation sessions (n = 10) or no additional contact (n = 10). The results show that those in the consultation condition reported higher psychological flexibility at the 3-month follow-up compared to the workshop-only condition. Improvements in ACT knowledge, overall burnout, and personal accomplishment were found in both groups, independent of whether they received phone consultation, and this increase was maintained over time. In conclusion, ACT phone consultation contributed to counselor psychological flexibility above the workshop alone and appears to be feasible as a means to improve counselor psychological flexibility.
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Affiliation(s)
- Jason B Luoma
- Portland Psychotherapy Clinic, Research, and Training Center, Portland, OR, USA.
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6
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Chase JA, Houmanfar R, Hayes SC, Ward TA, Vilardaga JP, Follette V. Values are not just goals: Online ACT-based values training adds to goal setting in improving undergraduate college student performance. Journal of Contextual Behavioral Science 2013. [DOI: 10.1016/j.jcbs.2013.08.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Vilardaga JP, Frank M, Krasel C, Dees C, Nissenson RA, Lohse MJ. Differential conformational requirements for activation of G proteins and the regulatory proteins arrestin and G protein-coupled receptor kinase in the G protein-coupled receptor for parathyroid hormone (PTH)/PTH-related protein. J Biol Chem 2001; 276:33435-43. [PMID: 11387315 DOI: 10.1074/jbc.m011495200] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
After stimulation with agonist, G protein-coupled receptors (GPCRs) activate G proteins and become phosphorylated by G protein-coupled receptor kinases (GRKs), and most of them translocate cytosolic arrestin proteins to the cytoplasmic membrane. Agonist-activated GPCRs are specifically phosphorylated by GRKs and are targeted for endocytosis by arrestin proteins, suggesting a connection between GPCR conformational changes and interaction with GRKs and arrestins. Previously, we showed that by substitution of histidine for residues at the cytoplasmic side of helix 3 (H3) and helix 6 (H6) of the parathyroid hormone (PTH) receptor (PTHR), a zinc metal ion-binding site is engineered that prevents PTH-stimulated G(s) activation (Sheikh, S. P., Vilardaga, J.-P., Baranski, T. J., Lichtarge, O., Iiri, T., Meng, E. C., Nissenson, R. A., and Bourne, H. R. (1999) J. Biol. Chem. 274, 17033-17041). These data suggest that relative movements between H3 and H6 are critical for G(s) activation. Does this molecular event play a similar role in activation of GRK and arrestin and in PTHR-mediated G(q) activation? To answer this question, we utilized the two previously described mutant forms of PTHR, H401 and H402, which contain a naturally present histidine residue at position 301 in H3 and a second substituted histidine residue at positions 401 and 402 in H6, respectively. Both mutant receptors showed inhibition of PTH-stimulated inositol phosphate and cAMP generation in the presence of increasing concentrations of Zn(II). However, the mutants showed no Zn(II)-dependent impairment of phosphorylation by GRK-2. Likewise, the mutants were indistinguishable from wild-type PTHR in the ability to translocate beta-arrestins/green fluorescent protein to the cell membrane and were also not affected by sensitivity to Zn(II). These results suggest that agonist-mediated phosphorylation and internalization of PTHR require conformational switches of the receptor distinct from the cAMP and inositol phosphate signaling state. Furthermore, PTHR sequestration does not appear to require G protein activation.
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Affiliation(s)
- J P Vilardaga
- Department of Pharmacology, Institute of Pharmacology and Toxicology, University of Würzburg, D-97078 Würzburg, Germany
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Vilardaga JP, Lin I, Nissenson RA. Analysis of parathyroid hormone (PTH)/secretin receptor chimeras differentiates the role of functional domains in the pth/ pth-related peptide (PTHrP) receptor on hormone binding and receptor activation. Mol Endocrinol 2001; 15:1186-99. [PMID: 11435617 DOI: 10.1210/mend.15.7.0665] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The type 1 parathyroid hormore receptor (PTH1r) belongs to the class II family of G protein-coupled receptors. To delineate the sites in the PTH1r's N-terminal region, and the carboxy-core domain (transmembrane segments + extracellular loops) involved in PTH binding, we have evaluated the functional properties of 27 PTH1-secretin chimeras receptors stably expressed in HEK-293 cells. The wild type and chimeric receptors were analyzed for cell surface expression, binding for PTH and secretin, and functional responsiveness (cAMP induction) toward secretin and PTH. The expression levels of the chimeric receptors were comparable to that of the PTH1r (60-100%). The N-terminal region of PTH1r was divided into three segments that were replaced either singly or in various combinations with the homologous region of the secretin receptor (SECr). Substitution of the carboxy-terminal half (residues 105-186) of the N-terminal region of PTH1r for a SECr homologous segment did not reduced affinity for PTH but abolished signaling in response to PTH. This data indicate that receptor activation is dissociable from high affinity hormone binding in the PTH1r, and that the N-terminal region might play a critical role in the activation process. Further segment replacements in the N-termini focus on residues 105-186 and particularly residues 146-186 of PTH1r as providing critical segments for receptor activation. The data obtained suggest the existence of two distinct PTH binding sites in the PTH1r's N-terminal region: one site in the amino-terminal half (residues 1-62) (site 1) that participates in high-affinity PTH binding; and a second site of lower affinity constituted by amino acid residues scattered throughout the carboxy-terminal half (residues 105-186) (site 2). In the absence of PTH binding to site 1, higher concentrations of hormone are required to promote receptor activation. In addition, elimination of the interaction of PTH with site 2 results in a loss of signal transduction without loss of high-affinity PTH binding. Divers substitutions of the extracellular loops of the PTH1r highlight the differential role of the first- and third extracellular loop in the process of PTH1r activation after hormone binding. A chimera containing the entire extracellular domains of the PTH1r and the transmembrane + cytoplasmic domains of SECr had very low PTH binding affinity and did not signal in response to PTH. Further substitution of helix 5 of PTH1r in this chimera increased affinity for PTH that is close to the PTH affinity for the wild-type PTH1r but surprisingly, did not mediate signaling response. Additional substitutions of PTH1r's helices in various combinations emphasize the fundamental role of helix 3 and helix 6 on the activation process of the PTH1r. Overall, our studies demonstrated that several PTH1r domains contribute differentially to PTH binding affinity and signal transduction mechanism and highlight the role of the N-terminal domain and helix 3 and helix 6 on receptor activation.
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MESH Headings
- Amino Acid Sequence
- Animals
- Binding Sites
- Cell Line
- Embryo, Mammalian
- Gene Expression
- Humans
- Kidney
- Molecular Sequence Data
- Opossums
- Parathyroid Hormone/metabolism
- Peptide Fragments/chemistry
- Peptide Fragments/genetics
- Protein Structure, Secondary
- Rats
- Receptor, Parathyroid Hormone, Type 1
- Receptors, G-Protein-Coupled
- Receptors, Gastrointestinal Hormone/chemistry
- Receptors, Gastrointestinal Hormone/genetics
- Receptors, Gastrointestinal Hormone/physiology
- Receptors, Parathyroid Hormone/chemistry
- Receptors, Parathyroid Hormone/genetics
- Receptors, Parathyroid Hormone/physiology
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/physiology
- Signal Transduction
- Structure-Activity Relationship
- Transfection
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Affiliation(s)
- J P Vilardaga
- Endocrine Research Unit Veterans' Affairs Medical Center and Departments of Medicine and Physiology University of California San Francisco, California 94121, USA.
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9
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Di Paolo E, Vilardaga JP, Petry H, Moguilevsky N, Bollen A, Robberecht P, Waelbroeck M. Role of charged amino acids conserved in the vasoactive intestinal polypeptide/secretin family of receptors on the secretin receptor functionality. Peptides 1999; 20:1187-93. [PMID: 10573290 DOI: 10.1016/s0196-9781(99)00122-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The secretin receptor is a member of a large family of G-protein-coupled receptors that recognize polypeptide hormone and/or neuropeptides. Charged, conserved residues might play a key role in their function, either by interacting with the ligand or by stabilizing the receptor structure. Of the four charged amino acids that are conserved in the whole secretin receptor family, D49 and R83 (in the N-terminal domain) were probably important for the secretin receptor structure: replacement of D49 by H or R and of R83 by D severely reduced both the maximal response to secretin and its potency. No functional secretin receptor could be detected after replacement of R83 by L. Mutation of D49 to E, A, or N had no effect or reduced 5-fold the potency of secretin. The highly conserved positive charges found at the extracellular ends of TM III (K194) and IV (R255) were important for the secretin receptor function, as K194 mutation to A or Q and R255 mutation to Q or D decreased the secretin's affinity 15- to 1000-fold, respectively. Six extracellular charged residues are conserved in closely related receptors but not in the whole family. K121 (TM I) and R277 (TM V) were not important for functional secretin receptor expression. D174 (TM II) was necessary to stabilize the active receptor structure: the D174N mutant receptors were unable to stimulate normally the adenylate cyclase in response to secretin, and functional D174A receptors could not be found. Mutation of R255, E259 (second extracellular loop), and E351 (third extracellular loop) to uncharged residues reduced only 10- to 100-fold the secretin potency without changing its efficacy: these residues either stabilized the active receptor conformation or formed hydrogen rather than ionic bonds with secretin. Mutation of K121 (TM I) to Q or L and of R277 (TM V) to E or Q did not affect the receptor functional properties.
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MESH Headings
- Adenylyl Cyclases/metabolism
- Amino Acid Sequence
- Amino Acids/physiology
- Animals
- CHO Cells
- Conserved Sequence
- Cricetinae
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Protein Structure, Secondary
- Rats
- Receptors, G-Protein-Coupled
- Receptors, Gastrointestinal Hormone/chemistry
- Receptors, Gastrointestinal Hormone/genetics
- Receptors, Gastrointestinal Hormone/metabolism
- Receptors, Gastrointestinal Hormone/physiology
- Receptors, Vasoactive Intestinal Peptide/chemistry
- Receptors, Vasoactive Intestinal Peptide/genetics
- Receptors, Vasoactive Intestinal Peptide/metabolism
- Receptors, Vasoactive Intestinal Peptide/physiology
- Secretin/metabolism
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Affiliation(s)
- E Di Paolo
- Department of Biochemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Belgium
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10
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Vilardaga JP, Di Paolo E, Bialek C, De Neef P, Waelbroeck M, Bollen A, Robberecht P. Mutational analysis of extracellular cysteine residues of rat secretin receptor shows that disulfide bridges are essential for receptor function. Eur J Biochem 1997; 246:173-80. [PMID: 9210480 DOI: 10.1111/j.1432-1033.1997.00173.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We attempted to express point-mutant secretin receptors where each of the 10 extracellular Cys residues was replaced by a Ser residue, in Chinese hamster ovary (CHO) cells. Six of the point-mutant receptors (C24-->S, C44-->S, C53-->S, C67-->S, C85-->S and C101-->S) could not be detected by binding or functional studies: the mutations resulted in functional inactivation of the receptor. In contrast, the four other point-mutant receptors (C11-->S, C186-->S, C193-->S and C263-->S) were able to bind poorly 125I-secretin, and to activate adenylate cyclase with high secretin EC50 values. These results suggest that cysteine residues 24, 44, 53, 67, 85 and 101 are necessary for receptor function, and that the two putative disulfide bridges formed by cysteine residues 11, 186, 193 and 263 are functionally relevant, but not essential for receptor expression. Secretin activated the adenylate cyclase through the quadruple mutant (C11,186,193,263-->S), the four triple mutants, and through double mutants C186,193-->S and C186,263-->S with a very high (microM) EC50 value, suggesting that, in the wild-type receptor, disulfide bridges are formed between C11-C186, and between C193-C263. Prior treatment with dithiothreitol resulted in a marked EC50 increase of the wild-type receptor and of those receptors with at least the two cysteine residues in positions 11 and 186, suggesting that the C11-C186 (but not the C193-C263) disulfide bridge was accessible to this reducing agent. Several results nevertheless indicated that, in mutant receptors, alternative disulfide bridges can be formed between cysteine 186 and cysteine 193 or 263, suggesting that these three residues are in close spatial proximity in the wild-type receptor.
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Affiliation(s)
- J P Vilardaga
- Department of Applied Genetics, Faculty of Sciences, Université Libre de Bruxelles, Belgium
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11
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Gourlet P, Vilardaga JP, De Neef P, Vandermeers A, Waelbroeck M, Bollen A, Robberecht P. Interaction of amino acid residues at positions 8-15 of secretin with the N-terminal domain of the secretin receptor. Eur J Biochem 1996; 239:349-55. [PMID: 8706739 DOI: 10.1111/j.1432-1033.1996.0349u.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The ability of secretin, PACAP-(1-27)-peptide, and ten hybrid peptides to recognize and activate the rat secretin and vasoactive intestinal polypeptide (PACAP type II VIP1) receptors was tested on recombinant Chinese hamster ovary (CHO) cell lines. PACAP had a 2500-fold lower affinity than secretin for the secretin receptor, and secretin had a 300-fold lower affinity than PACAP for the VIP1 receptor. Amino acids 8, 13, and 15 of the PACAP molecule contributed significantly to the low affinity of PACAP for the secretin receptor. The amino acids at positions 5, 9, 10, 15, 16, and unidentified amino acid(s) between positions 17-20 made limited contributions to the low affinity of secretin for the VIP1 receptor. To identify the receptor region that interacts with these amino acids, we constructed chimeric receptors, which consist either of the N-terminal extracellular part of the secretin receptor and the core of the VIP1 receptor (N-Sn/VIP1r) or the N-terminal extracellular part of the VIP1 receptor and the core of the secretin receptor (N-VIP1/Snr), and tested the ability of the hybrid ligands to activate the adenylate cyclase of CHO cells expressing these chimeric receptors. The N-Sn/VIP1 receptors had a higher affinity for secretin than for PACAP. The hybrid peptide 6 that consists of the PACAP-(1-8)-Sn-(9-15)-PACAP-(16-27)-peptide sequence had a 30-fold to 200-fold higher potency than either parent peptide for the chimeric receptor, which suggests that while the N- and/or C-terminal part of the peptide interact with the transmembrane domain of the receptor, the discriminator region 9-15 recognizes the extracellular N-terminal domain of the receptor. This was confirmed by the observation that, out of all the peptides tested, hybrid 6 had the weakest potency for activation of the N-VIP1/Sn chimeric receptors.
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Affiliation(s)
- P Gourlet
- Department of Biochemistry and Nutrition, School of Medicine, Université Libre de Bruxelles, Belgium
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Vilardaga JP, di Paolo E, de Neef P, Waelbroeck M, Bollen A, Robberecht P. Lysine 173 residue within the first exoloop of rat secretin receptor is involved in carboxylate moiety recognition of Asp 3 in secretin. Biochem Biophys Res Commun 1996; 218:842-6. [PMID: 8579602 DOI: 10.1006/bbrc.1996.0150] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The contribution of the extracellular loops of the secretin receptor to the recognition of secretin was investigated by transfection in CHO cells of chimeric receptors, in which the three loops of the secretin recombinant receptor were replaced by the corresponding sequences of the glucagon receptor. The role of the third loop could not be evaluated as the transfected cells did not respond to secretin. Replacement of extracellular loop 2 reduced markedly the capability of secretin to occupy the receptor but did not alter the capacity of the receptor to discriminate between peptide analogues modified in position 3. Replacement of the first extracellular loop not only reduced the potency of secretin but also decreased the capacity of the receptor to discriminate between ligands having in position 3 an aspartate (as in secretin), an asparagine, or a glutamic acid. This change in receptor properties was reproduced by a single mutation of lysine 173 of the receptor into isoleucine. Thus, the basic amino acid in position 173 is likely to interact with aspartate 3 of secretin. As an aspartate is also present in position 3 of VIP and PACAP, two peptides related to secretin, and a lysine residue is conserved in the first extracellular loop of the VIP and PACAP receptors, this interaction may be a key element of peptide recognition by this receptor family.
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Affiliation(s)
- J P Vilardaga
- Department of Biochemistry and Nutrition, School of Medicine, Université Libre de Bruxelles, Belgium
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Gourlet P, Vilardaga JP, De Neef P, Waelbroeck M, Vandermeers A, Robberecht P. The C-terminus ends of secretin and VIP interact with the N-terminal domains of their receptors. Peptides 1996; 17:825-9. [PMID: 8844773 DOI: 10.1016/0196-9781(96)00107-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
C-terminally truncated secretin and VIP molecules were synthesized, and their ability to occupy the recombinant secretin and VIP1 receptors stably expressed in Chinese hamster ovary (CHO) cells and to stimulate adenylate cyclase activity was studied. On secretin receptors, secretin (1-26) and secretin (1-24) were 10- and 50-fold less potent but as efficient as secretin (1-27); VIP (1-27) was as potent and efficient as VIP (1-28), and VIP (1-26) and VIP (1-25) were both 100-fold less potent. On VIP1 receptor, VIP (1-28) and VIP (1-27) were equipotent and VIP (1-26) and VIP (1-25) were 10- and 300-fold less potent, respectively; secretin (1-27) and secretin (1-26) were of equally low affinity and 10-fold more potent than secretin (1-24). Thus, the secretin and the VIP1 receptors had different selectivity profiles for the recognition of C-terminally truncated secretin and VIP derivatives. The chimeric receptors consisting in the N-terminal part of the secretin receptor on the core of the VIP1 receptor (N-Sn/VIP1.r) and in the N-terminal part of the VIP1 receptor on the core of the secretin receptor (N-VIP1/Sn.r) exhibited the selectivity pattern of the secretin and VIP1 receptors, respectively. The results suggest that the C-terminal end of secretin and VIP interacts with the N-terminal domain of the secretin and VIP receptors.
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Affiliation(s)
- P Gourlet
- Department of Biochemistry and Nutrition, Medical School, Université Libre de Bruxelles, Belgium
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Vilardaga JP, De Neef P, Di Paolo E, Bollen A, Waelbroeck M, Robberecht P. Properties of chimeric secretin and VIP receptor proteins indicate the importance of the N-terminal domain for ligand discrimination. Biochem Biophys Res Commun 1995; 211:885-91. [PMID: 7598719 DOI: 10.1006/bbrc.1995.1895] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Two chimeras were obtained by substituting the DNA sequence encoding the N-terminal extracellular domain of the VIP and secretin receptors by the homologous DNA sequence encoding the secretin (N-Sn/VIP.r) and VIP receptor (N-VIP/Sn.r), respectively. These chimeric receptors were transfected and stably expressed in CHO cells. Their pharmacological properties were then compared to the corresponding recombinant "wild type" receptors, expressed in the same cell line. Binding data were obtained for the wild types and the N-VIP/Sn.r but not for the N-Sn/VIP receptor. Functional data (adenylate cyclase activation) were obtained in all cases. In order to minimize the effects of an excess of receptors and thus, to compare validly binding and functional data, we determined agonists EC50 values after down regulation of the receptors (i.e. after a pretreatment of the cells for 24 h with VIP or secretin). The order of potency of the peptides for receptor occupancy and adenylate cyclase activation indicated that the N-terminal extracellular domain of each receptor was the key element for discrimination between secretin and VIP.
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Affiliation(s)
- J P Vilardaga
- Department of Biochemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Belgium
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Vilardaga JP, Di Paolo E, Bollen A. Improved PCR method for high-efficiency site-directed mutagenesis using class 2S restriction enzymes. Biotechniques 1995; 18:604-6. [PMID: 7598888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Ciccarelli E, Svoboda M, De Neef P, Di Paolo E, Bollen A, Dubeaux C, Vilardaga JP, Waelbroeck M, Robberecht P. Pharmacological properties of two recombinant splice variants of the PACAP type I receptor, transfected and stably expressed in CHO cells. Eur J Pharmacol 1995; 288:259-67. [PMID: 7774670 DOI: 10.1016/0922-4106(95)90037-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Two splice variants of the pituitary adenylate cyclase activating polypeptide (PACAP) type I receptor (PACAP receptor and PACAP/HOP receptor isoform) were stably expressed in Chinese hamster ovary (CHO) cells that did not express constitutively receptors for this family of peptides. The PACAP/HOP receptor protein had a 28 amino acid extension in the C-terminal part of the third intracellular loop. The two cell lines studied, CHO 2-10 (PACAP receptor) and CHO 4-12 (PACAP/HOP receptor) expressed a receptor density of 4.6 +/- 0.3 and 2.6 +/- 0.2 pmol/mg protein, respectively, with corresponding Kd values of 14.2 +/- 2.0 and 8.2 +/- 1.0 nM for [Ac-His1]PACAP-27 used as a tracer. Tracer binding was slightly decreased by GTP in both clones. The Kd values of PACAP-27, PACAP-38, vasoactive intestinal peptide (VIP), PACAP-27 fragments and analogues evaluated by binding competition curves, were higher in CHO 2-10 than in CHO 4-12, whereas the Kd for PACAP-38 fragments did not differ. The receptors were coupled to adenylate cyclase and the EC50 values were lower than the Kd values in both cell lines, suggesting an amplification process due to the existence of spare receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- E Ciccarelli
- Department of Biochemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Belgium
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Ciccarelli E, Vilardaga JP, De Neef P, Di Paolo E, Waelbroeck M, Bollen A, Robberecht P. Properties of the VIP-PACAP type II receptor stably expressed in CHO cells. Regul Pept 1994; 54:397-407. [PMID: 7716273 DOI: 10.1016/0167-0115(94)90537-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The VIP receptor cloned from rat lung (VIP1 receptor from the group of the PACAP-VIP type II receptors) was inserted into a mammalian expression vector and stably transfected into Chinese hamster ovary cells (CHO). Two clones were selected, expressing respectively a high (850 +/- 50 fmol/mg protein, for clone 3) and a low (100 +/- 30 fmol/mg protein for clone 16) number of receptors. Both clones had the same apparent Kd value of binding for VIP and related peptides. The receptor expressed had the same binding properties as the natural VIP receptor, judged from the relative potency of VIP and PACAP analogues and fragments. The EC50 value of adenylate cyclase activation were 3 to 10 fold lower in clone 3 than in 16. The values observed in clone 16 were closer to the binding Kd values. The differences between the two clones were explained by the existence of spare receptors in clone 3, since: (a) the relative efficacy of some fragments were lower in clone 16 than in clone 3; (b) pretreatment of the cells with VIP reduced the number of receptors in both clones and increased the EC50 value for VIP in clone 3 but decreased peptide efficacy in clone 16 without significant change of the EC50 value.
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Affiliation(s)
- E Ciccarelli
- Department of Biochemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Belgium
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Vilardaga JP, Ciccarelli E, Dubeaux C, De Neef P, Bollen A, Robberecht P. Properties and regulation of the coupling to adenylate cyclase of secretin receptors stably transfected in Chinese hamster ovary cells. Mol Pharmacol 1994; 45:1022-8. [PMID: 8190092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The binding properties, coupling to adenylate cyclase, and desensitization of secretin receptors stably expressed in transfected Chinese hamster ovary (CHO) cells were compared in two clones expressing high (CHO-SnR-c5, 450 +/- 80 fmol/mg of protein) and low (CHO-SnR-c1, 40 +/- 25 fmol/mg of protein) receptor densities. The Kd values for receptor occupancy by secretin, selected analogues, and fragments were identical in CHO-SnR-c1 and -c5 cells and identical to those described for native receptors from NG 108-15 cells. The Kact values for adenylate cyclase stimulation were identical to the Kd values in CHO-SnR-c1 cells but 5-10-fold higher than those in CHO-SnR-c5 cells. The Kact values in both CHO-SnR-c1 and -c5 cell lines were reduced in the presence of the nonhydrolyzable GTP derivative guanosine-5'-(beta, gamma-imido)triphosphate and after pretreatment of the cells with cholera toxin. Preincubation of both CHO-SnR-c1 and -c5 cell lines with secretin for 24 hr reduced their binding capacity and reduced secretin efficacy in CHO-SnR-c1 cells and secretin potency in CHO-SnR-c5 cells. These results suggest efficient coupling of the secretin receptor to the adenylate cyclase machinery and the existence of spare receptors in the clone expressing higher receptor density. Pretreatment of the two cell lines with the reducing agent dithiothreitol reduced the binding capacity and induced the appearance of a low affinity binding component. In both cell lines, dithiothreitol pretreatment decreased secretin potency but not secretin efficacy, suggesting the necessity of integrity of the disulfide bridges for optimal receptor recognition.
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Affiliation(s)
- J P Vilardaga
- Laboratory of Biochemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Belgium
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