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Robbins SM, Pelletier JP, Abram F, Boily M, Antoniou J, Martineau PA, Morelli M, Martel-Pelletier J. Gait risk factors for disease progression differ between non-traumatic and post-traumatic knee osteoarthritis. Osteoarthritis Cartilage 2021; 29:1487-1497. [PMID: 34348184 DOI: 10.1016/j.joca.2021.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 06/18/2021] [Accepted: 07/24/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To examine if relationships between knee osteoarthritis (OA) progression with knee moments and muscle activation during gait vary between patients with non-traumatic and post-traumatic knee OA. DESIGN This longitudinal study included participants with non-traumatic (n = 17) and post-traumatic (n = 18) knee OA; the latter group had a previous anterior cruciate ligament rupture. Motion capture cameras, force plates, and surface electromyography measured knee moments and lower extremity muscle activation during gait. Cartilage volume change were determined over 2 years using magnetic resonance imaging in four regions: medial and lateral plateau and condyle. Linear regression analysis examined relationships between cartilage change with gait metrics (moments, muscle activation), group, and their interaction. RESULTS Measures from knee adduction and rotation moments were related to lateral condyle cartilage loss in both groups, and knee adduction moment to lateral plateau cartilage loss in the non-traumatic group only [β = -1.336, 95% confidence intervals (CI) = -2.653 to -0.019]. Generally, lower levels of stance phase muscle activation were related to greater cartilage loss. The relationship between cartilage loss in some regions with muscle activation characteristics varied between non-traumatic and post-traumatic groups including for: lateral hamstring (lateral condyle β = 0.128, 95%CI = 0.003 to 0.253; medial plateau β = 0.199, 95%CI = 0.059 to 0.339), rectus femoris (medial condyle β = -0.267, 95%CI = -0.460 to -0.073), and medial hamstrings (medial plateau; β = -0.146, 95%CI = -0.244 to -0.048). CONCLUSION Findings indicate that gait risk factors for OA progression may vary between patients with non-traumatic and post-traumatic knee OA. These OA subtypes should be considered in studies that investigate gait metrics as risk factors for OA progression.
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Affiliation(s)
- S M Robbins
- Centre for Interdisciplinary Research in Rehabilitation, Lethbridge-Layton-MacKay Rehabilitation Centre, PERFORM Centre, School of Physical and Occupational Therapy, McGill University, Montreal, Canada.
| | - J-P Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Montreal, Canada.
| | - F Abram
- Medical Imaging, ArthroLab Inc., Montreal, Canada.
| | - M Boily
- Department of Diagnostic Radiology, McGill University, Royal Victoria Hospital, Montreal, Canada.
| | - J Antoniou
- Division of Orthopaedic Surgery, Jewish General Hospital and McGill University, Montreal, Canada.
| | - P A Martineau
- Division of Orthopaedic Surgery, McGill University Health Centre and McGill University, Montreal, Canada.
| | - M Morelli
- Division of Orthopedic Surgery, St. Mary's Hospital Center and McGill University, Montreal, Canada.
| | - J Martel-Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Montreal, Canada.
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Ippersiel P, Robbins SM, Dixon PC. Lower-limb coordination and variability during gait: The effects of age and walking surface. Gait Posture 2021; 85:251-257. [PMID: 33626449 DOI: 10.1016/j.gaitpost.2021.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 02/05/2021] [Accepted: 02/10/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Falls among community-dwelling older adults are often triggered by uneven walkways. Joint coordination and its variability change with age and may place older adults at risk of falling. It is unclear how irregular surfaces impact lower-limb joint coordination and if such changes are exacerbated by aging. RESEARCH QUESTION To what extent do lower-limb inter-joint coordination and its variability, over flat and uneven brick walkways, differ between older and young healthy adults? METHODS A motion-capture system collected kinematic data from walking trials on flat and uneven walkways in seventeen older (72.0 ± 4.2 years) and eighteen younger (27.0 ± 4.7 years) healthy adults. Continuous relative phase analyses were performed for the Knee-Hip and Ankle-Knee joint pairs. Mean Absolute Relative Phase (MARP) quantified coordination amplitude. Deviation Phase (DP) quantified coordinative variability. Two-way mixed ANOVA's tested for effects of age, surface, and age × surface interactions. RESULTS Uneven surfaces prompted more in-phase MARP inter-joint coordination in adults during most gait phases (p ≤ 0.024). Age × surface interactions were observed during initial contact (Ankle-Knee: p = 0.021, Knee-Hip: p = 0.001) and loading response (Knee-Hip: p = 0.017), with post-hoc analyses showing coordination accentuated in older adults. Uneven surfaces induced higher DP in Knee-Hip (p = 0.017) and Ankle-Knee joint coupling (p < 0.001) during gait, largely independent of age. An age × surface interaction was observed during mid-swing (p = 0.050), with post-hoc analysis revealing increased variability in older adults. SIGNIFICANCE More in-phase and variable lower-limb gait behavior was observed on uneven walkways. These differences were accentuated in older adults during early stance phase (more tightly coordinated) and mid-swing (more variable). This may reflect a cautious gait strategy on challenging walkways to maintain stability and help prevent falls.
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Affiliation(s)
- P Ippersiel
- School of Physical and Occupational Therapy, McGill University, Montreal, Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Lethbridge-Layton-Mackay Rehabilitation Centre, Montreal, Québec, Canada.
| | - S M Robbins
- School of Physical and Occupational Therapy, McGill University, Montreal, Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Lethbridge-Layton-Mackay Rehabilitation Centre, Montreal, Québec, Canada
| | - P C Dixon
- School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Canada; Research Center of the Sainte-Justine University Hospital (CRCHUSJ), Canada
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Robbins SM, Morelli M, Martineau PA, St-Onge N, Boily M, Dimentberg R, Antoniou J. A comparison of muscle activation and knee mechanics during gait between patients with non-traumatic and post-traumatic knee osteoarthritis. Osteoarthritis Cartilage 2019; 27:1033-1042. [PMID: 30898621 DOI: 10.1016/j.joca.2019.02.798] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/25/2019] [Accepted: 02/27/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The objective was to compare muscle activation and knee mechanics during gait between participants with non-traumatic knee osteoarthritis (OA), post-traumatic knee OA, and healthy adults. DESIGN Participants with non-traumatic knee OA (n = 22), post-traumatic knee OA (n = 19), and healthy adults (n = 22) completed gait trials for this observational, cross-sectional study. Post-traumatic OA group had a history of traumatic anterior cruciate ligament (ACL) rupture. Surface electromyography (EMG) measured activation of seven lower extremity muscles. Motion capture cameras and force plates measured motion and force data. Principal component analysis (PCA) determined waveform characteristics (principal components) from EMG, knee angle, and knee external moment waveforms. Analysis of variance (ANOVA) examined group differences in principal component scores (PC-scores). Regression analyses examined if a variable that coded for OA group could predict PC-scores after accounting for disease severity, alignment, and lateral OA. RESULTS There was lower gastrocnemius EMG amplitudes (P < 0.01; ANOVA) in the post-traumatic OA group compared to healthy group. Non-traumatic OA group had higher vastus lateralis, vastus medialis, and rectus femoris EMG compared to post-traumatic OA group (P = 0.01 to 0.04) in regression analyses. Also, non-traumatic OA group had higher and prolonged lateral hamstring EMG compared to healthy (P = 0.03; ANOVA) and post-traumatic OA (P = 0.04; regression) groups respectively. The non-traumatic OA group had lower knee extension (P < 0.05) and medial rotation (P < 0.05) moments than post-traumatic and healthy groups. CONCLUSIONS Muscle activation and knee mechanics differed between participants with non-traumatic and post-traumatic knee OA and healthy adults. These OA subtypes had differences in disease characteristics that may impact disease progression.
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Affiliation(s)
- S M Robbins
- Centre for Interdisciplinary Research in Rehabilitation, Constance Lethbridge Rehabilitation Centre and the School of Physical and Occupational Therapy, McGill University, Canada.
| | - M Morelli
- Division of Orthopedic Surgery, St. Mary's Hospital Center and McGill University, Canada.
| | - P A Martineau
- Division of Orthopaedic Surgery, McGill University Health Centre and McGill University, Canada.
| | - N St-Onge
- Centre for Interdisciplinary Research in Rehabilitation, PERFORM Centre, Department of Exercise Science, Concordia University, Canada.
| | - M Boily
- Department of Diagnostic Radiology, McGill University and Royal Victoria Hospital, Canada.
| | - R Dimentberg
- Division of Orthopedic Surgery, St. Mary's Hospital Center and McGill University, Canada.
| | - J Antoniou
- Division of Orthopaedic Surgery, Jewish General Hospital and McGill University, Canada.
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Robbins SM, Abram F, Boily M, Pelletier JP, Martel-Pelletier J. Relationship between alignment and cartilage thickness in patients with non-traumatic and post-traumatic knee osteoarthritis. Osteoarthritis Cartilage 2019; 27:630-637. [PMID: 30654119 DOI: 10.1016/j.joca.2019.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 11/30/2018] [Accepted: 01/03/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To compare cartilage thickness between patients with non-traumatic and post-traumatic knee osteoarthritis (OA) and healthy controls and to determine if disease severity and alignment impact these differences. DESIGN Participants with non-traumatic (n = 22) and post-traumatic (n = 19) knee OA, and healthy controls (n = 22) were recruited for this cross-sectional study. Participants underwent 3T magnetic resonance imaging (T1-weighted, 3D sagittal gradient echo sequence) and cartilage thickness was determined in four regions: medial and lateral condyle, and medial and lateral plateau. Lower extremity alignment (mechanical axis angle) and disease severity (Kellgren-Lawrence scores) were measured from full length radiographs. Statistical analysis included one-way analysis of variance (ANOVA) and modified Bonferroni test adjusting for multiple pairwise comparisons. Linear regression analyses examined the relationship between cartilage thickness and knee OA group after controlling for disease severity, meniscal status, and alignment. RESULTS In participants with predominantly medial compartment knee OA, compared to healthy controls, those with non-traumatic knee OA had diminished cartilage thickness in the medial plateau (p = 0.035) and those with post-traumatic knee OA had greater cartilage thickness in the lateral condyle (p = 0.044). In the lateral condyle, data revealed that alignment accounted for the variance in cartilage thickness (p = 0.035), in which a stronger relationship was found in the non-traumatic (r = -0.61) than the post-traumatic (r = -0.12) OA group. CONCLUSIONS Emerging data demonstrated that participants with non-traumatic knee OA have a stronger relationship between alignment and cartilage thickness than those with post-traumatic knee OA. This indicates that factors involved in knee OA initiation and progression may differ between these OA subtypes.
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Affiliation(s)
- S M Robbins
- Centre for Interdisciplinary Research in Rehabilitation, Constance Lethbridge Rehabilitation Centre, PERFORM Centre, and School of Physical and Occupational Therapy, McGill University, Montreal, Canada.
| | - F Abram
- Medical Imaging, ArthroLab Inc., Montreal, Canada.
| | - M Boily
- Department of Diagnostic Radiology, McGill University, Royal Victoria Hospital, Montreal, Canada.
| | - J-P Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Montreal, Canada.
| | - J Martel-Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Montreal, Canada.
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Alshehri MM, Robbins SM, Senger DL. The Role of Neurotrophin Signaling in Gliomagenesis: A Focus on the p75 Neurotrophin Receptor (p75 NTR/CD271). Vitam Horm 2017; 104:367-404. [PMID: 28215302 DOI: 10.1016/bs.vh.2016.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The p75 neurotrophin receptor (p75NTR, a.k.a. CD271), a transmembrane glycoprotein and a member of the tumor necrosis family (TNF) of receptors, was originally identified as a nerve growth factor receptor in the mid-1980s. While p75NTR is recognized to have important roles during neural development, its presence in both neural and nonneural tissues clearly supports the potential to mediate a broad range of functions depending on cellular context. Using an unbiased in vivo selection paradigm for genes underlying the invasive behavior of glioma, a critical characteristic that contributes to poor clinical outcome for glioma patients, we identified p75NTR as a central regulator of glioma invasion. Herein we review the expanding role that p75NTR plays in glioma progression with an emphasis on how p75NTR may contribute to the treatment refractory nature of glioma. Based on the observation that p75NTR is expressed and functional in two critical glioma disease reservoirs, namely, the highly infiltrative cells that evade surgical resection, and the radiation- and chemotherapy-resistant brain tumor-initiating cells (also referred to as brain tumor stem cells), we propose that p75NTR and its myriad of downstream signaling effectors represent rationale therapeutic targets for this devastating disease. Lastly, we provide the provocative hypothesis that, in addition to the well-documented cell autonomous signaling functions, the neurotrophins, and their respective receptors, contribute in a cell nonautonomous manner to drive the complex cellular and molecular composition of the brain tumor microenvironment, an environment that fuels tumorigenesis.
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Affiliation(s)
- M M Alshehri
- Arnie Charbonneau Cancer Centre, University of Calgary, Calgary, AB, Canada
| | - S M Robbins
- Arnie Charbonneau Cancer Centre, University of Calgary, Calgary, AB, Canada
| | - D L Senger
- Arnie Charbonneau Cancer Centre, University of Calgary, Calgary, AB, Canada.
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Ahn BY, Saldanha-Gama RFG, Rahn JJ, Hao X, Zhang J, Dang NH, Alshehri M, Robbins SM, Senger DL. Glioma invasion mediated by the p75 neurotrophin receptor (p75(NTR)/CD271) requires regulated interaction with PDLIM1. Oncogene 2015; 35:1411-22. [PMID: 26119933 PMCID: PMC4800290 DOI: 10.1038/onc.2015.199] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 04/23/2015] [Accepted: 05/10/2015] [Indexed: 01/05/2023]
Abstract
The invasive nature of glioblastoma renders them incurable by current therapeutic interventions. Using a novel invasive human glioma model, we previously identified the neurotrophin receptor p75NTR (aka CD271) as a mediator of glioma invasion. Herein, we provide evidence that preventing phosphorylation of p75NTR on S303 by pharmacological inhibition of PKA, or by a mutational strategy (S303G), cripples p75NTR-mediated glioma invasion resulting in serine phosphorylation within the C-terminal PDZ-binding motif (SPV) of p75NTR. Consistent with this, deletion (ΔSPV) or mutation (SPM) of the PDZ motif results in abrogation of p75NTR-mediated invasion. Using a peptide-based strategy, we identified PDLIM1 as a novel signaling adaptor for p75NTR and provide the first evidence for a regulated interaction via S425 phosphorylation. Importantly, PDLIM1 was shown to interact with p75NTR in highly invasive patient-derived glioma stem cells/tumor-initiating cells and shRNA knockdown of PDLIM1 in vitro and in vivo results in complete ablation of p75NTR-mediated invasion. Collectively, these data demonstrate a requirement for a regulated interaction of p75NTR with PDLIM1 and suggest that targeting either the PDZ domain interactions and/or the phosphorylation of p75NTR by PKA could provide therapeutic strategies for patients with glioblastoma.
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Affiliation(s)
- B Y Ahn
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hughes Childhood Cancer Program, University of Calgary, Calgary, Alberta, Canada.,Department of Oncology, University of Calgary, Calgary, Alberta, Canada
| | - R F G Saldanha-Gama
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Oncology, University of Calgary, Calgary, Alberta, Canada.,Clark H. Smith Brain Tumour Centre, University of Calgary, Calgary, Alberta, Canada
| | - J J Rahn
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hughes Childhood Cancer Program, University of Calgary, Calgary, Alberta, Canada.,Department of Oncology, University of Calgary, Calgary, Alberta, Canada
| | - X Hao
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hughes Childhood Cancer Program, University of Calgary, Calgary, Alberta, Canada.,Department of Oncology, University of Calgary, Calgary, Alberta, Canada
| | - J Zhang
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Clark H. Smith Brain Tumour Centre, University of Calgary, Calgary, Alberta, Canada
| | - N-H Dang
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Oncology, University of Calgary, Calgary, Alberta, Canada.,Clark H. Smith Brain Tumour Centre, University of Calgary, Calgary, Alberta, Canada
| | - M Alshehri
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Oncology, University of Calgary, Calgary, Alberta, Canada.,Clark H. Smith Brain Tumour Centre, University of Calgary, Calgary, Alberta, Canada
| | - S M Robbins
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hughes Childhood Cancer Program, University of Calgary, Calgary, Alberta, Canada.,Department of Oncology, University of Calgary, Calgary, Alberta, Canada.,Clark H. Smith Brain Tumour Centre, University of Calgary, Calgary, Alberta, Canada
| | - D L Senger
- Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hughes Childhood Cancer Program, University of Calgary, Calgary, Alberta, Canada.,Department of Oncology, University of Calgary, Calgary, Alberta, Canada.,Clark H. Smith Brain Tumour Centre, University of Calgary, Calgary, Alberta, Canada
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Maly MR, Robbins SM. Osteoarthritis year in review 2014: rehabilitation and outcomes. Osteoarthritis Cartilage 2014; 22:1958-88. [PMID: 25456293 DOI: 10.1016/j.joca.2014.08.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 08/09/2014] [Accepted: 08/15/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To highlight research studies examining rehabilitation for hip and knee osteoarthritis (OA), as well as the outcome measures used to assess treatment efficacy, published in 2013. DESIGN A systematic search was performed in Medline, CIHAHL and Embase databases from January to December 2013. The search was limited to 2013, human studies, and English. Rehabilitation intervention studies included were prospective controlled designs. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to evaluate the quality of evidence. First, individual articles were rated for quality. Second, articles were grouped based on outcome: OA disease markers, pain, physical function (self-reported, performance), and health. RESULTS Of 503 titles reviewed, 36 studies were included. The outcome measures related to OA disease markers were organized into subthemes of anthropometrics, biomechanics and physiology. The quality of evidence was of moderate, high, and low quality for anthropometric, biomechanical and physiological measures respectively. These studies supported the use of diet for weight loss combined with exercise. Bodies of evidence that showed the efficacy of exercise and passive strategies (thermal/electrical modalities, traction, manual therapy) for reducing pain were of low and moderate quality respectively. The evidence supporting diet and exercise, physiotherapy, and passive strategies to improve physical function was of moderate quality. Evidence supporting exercise to improve psychological factors was of moderate quality. CONCLUSIONS Exercise combined with diet for weight loss should be the mainstays of rehabilitation for people with knee and hip OA to provide benefit to OA disease markers, pain, physical function, and health.
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Affiliation(s)
- M R Maly
- School of Rehabilitation Science, McMaster University, Canada.
| | - S M Robbins
- Centre for Interdisciplinary Research in Rehabilitation, Constance Lethbridge Rehabilitation Centre, School of Physical and Occupational Therapy, McGill University, Canada.
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Senger DL, Rahn JJ, Hao X, Lun XWX, Cairncross JG, Weiss S, Venugopal C, McFarlane NM, Singh SK, Robbins SM, Senger DL. GLIOMA SPECIFIC PEPTIDES: A PLATFORM FOR MOLECULAR IMAGING AND THERAPEUTIC TARGETING. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou208.52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Robbins SM, Rastogi R, Howard J, Rosedale R. Comparison of measurement properties of the P4 pain scale and disease specific pain measures in patients with knee osteoarthritis. Osteoarthritis Cartilage 2014; 22:805-12. [PMID: 24721460 DOI: 10.1016/j.joca.2014.03.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 03/19/2014] [Accepted: 03/31/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To compare measurement properties of the P4 pain scale, Western Ontario and McMaster Universities Arthritis Index pain subscale (WOMAC-pain), and Intermittent and Constant Osteoarthritis Pain (ICOAP) measure in patients with knee osteoarthritis (OA). DESIGN A secondary analysis from a randomized controlled trial included participants (n = 156) with knee OA that were consulting with a surgeon regarding knee arthroplasty. They completed pain measures (P4, WOMAC-pain, ICOAP) and WOMAC-function subscale (WOMAC-function) at baseline and 2 weeks. Measurement properties assessed in various subgroups included floor/ceiling effects, test-retest reliability using intraclass correlation coefficients (ICC2,1), internal consistency using Cronbach's ɑ, factorial structure of each pain measure combined with WOMAC-function using principal component analysis, and responsiveness using standardized response mean (SRM). RESULTS P4 had low floor and ceiling effects (<1%). P4 test-retest reliability (ICC2,1 = 0.72), internal consistency (Chronbach's ɑ = 0.91), and responsiveness (SRM = 0.56) were similar to the values for WOMAC-pain and ICOAP. Factorial structure of P4 and ICOAP were separate from WOMAC-function items. WOMAC-pain and WOMAC-function items loaded on similar factors. ICOAP-constant subscale had a large floor effect (33%). CONCLUSIONS P4 should be used to measure pain in patients with knee OA. It had acceptable measurement properties which is comparable to more widely used pain measures. WOMAC-pain shared a factorial structure with WOMAC-function indicating these measures might be capturing the same construct, questioning its validity to measure pain separately from function. ICOAP had acceptable properties. More work should compare pain measures in less severely affected OA populations.
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Affiliation(s)
- S M Robbins
- Centre for Interdisciplinary Research in Rehabilitation, Constance Lethbridge Rehabilitation Centre, and School of Physical and Occupational Therapy, McGill University, Montreal, Canada.
| | - R Rastogi
- Department of Physiotherapy, London Health Sciences Centre, London, Canada.
| | - J Howard
- Division of Orthopedic Surgery, Western University and London Health Sciences Centre, London, Canada.
| | - R Rosedale
- Occupational Health and Safety Services, London Health Sciences Centre, London, Canada.
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Campbell TN, Attwell S, Arcellana-Panlilio M, Robbins SM. Ephrin A5 expression promotes invasion and transformation of murine fibroblasts. Biochem Biophys Res Commun 2006; 350:623-8. [PMID: 17022942 DOI: 10.1016/j.bbrc.2006.09.085] [Citation(s) in RCA: 19] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Accepted: 09/18/2006] [Indexed: 01/08/2023]
Abstract
Emerging evidence suggests involvement of the ephrin/Eph receptor system in tumourigenesis. Research on this new role has centred on the contribution of Eph receptors. In contrast, we focused on the elucidation of the role of ephrins, specifically ephrin A5. Results indicated an increase in invasive potential of ephrin A5-expressing murine fibroblasts, which was abolished by addition of a Src family kinase inhibitor. Furthermore, anchorage-independent growth was increased in ephrin A5-expressing cells. Stimulation with EphA5-Fc receptor increased colony size, but not colony number in ephrin A5 transfectants. Moreover, we observed morphogenetic transformation of ephrin A5-expressing 3T3 cells into a branching network when plated onto Matrigel. This behaviour was specific to ephrin A5 transfectants, as 3T3 cells expressing ephrin B1 displayed a phenotype similar to control 3T3 cells. We conclude that ectopic expression of ephrin A5 in murine fibroblasts elevates oncogenic potential, including increased invasive behaviour, anchorage-independent growth, and morphological transformation.
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Affiliation(s)
- T N Campbell
- Southern Alberta Cancer Research Institute, Department of Oncology, University of Calgary, Calgary, Alta., Canada T2N 4N1
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11
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Neely GG, Robbins SM, Amankwah EK, Epelman S, Wong H, Spurrell JC, Jandu KK, Zhu W, Fogg DK, Brown CB, Mody CH. Lipopolysaccharide-stimulated or granulocyte-macrophage colony-stimulating factor-stimulated monocytes rapidly express biologically active IL-15 on their cell surface independent of new protein synthesis. J Immunol 2001; 167:5011-7. [PMID: 11673509 DOI: 10.4049/jimmunol.167.9.5011] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although IL-15 shares many of the biological activities of IL-2, IL-2 expression is primarily under transcriptional regulation, while the mechanisms involved in the regulation of IL-15 are complex and not completely understood. In the current study, we found that CD14(+) monocytes constitutively exhibit both IL-15 mRNA and protein. IL-15 protein was found stored intracellularly and stimulation of CD14(+) monocytes with either LPS or GM-CSF resulted in mobilization of IL-15 stores to the plasma membrane. This rapidly induced surface expression was the result of a translocation of preformed stores, confirming that posttranslational regulatory stages limit IL-15, because it was not accompanied by an increase in IL-15 mRNA and occurred independent of de novo protein synthesis. After fixation, activated monocytes, but not resting monocytes, were found to support T cell proliferation, and this effect was abrogated by the addition of an IL-15-neutralizing Ab. The presence of preformed IL-15 stores and the ability of stimulated monocytes to mobilize these stores to their surface in an active form is a novel mechanism of regulation for IL-15.
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Affiliation(s)
- G G Neely
- Department of Medical Sciences, University of Calgary, Calgary, Alberta, Canada
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Besson A, Davy A, Robbins SM, Yong VW. Differential activation of ERKs to focal adhesions by PKC epsilon is required for PMA-induced adhesion and migration of human glioma cells. Oncogene 2001; 20:7398-407. [PMID: 11704869 DOI: 10.1038/sj.onc.1204899] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2001] [Revised: 08/01/2001] [Accepted: 08/07/2001] [Indexed: 11/09/2022]
Abstract
Protein kinase C (PKC) is a family of serine/threonine kinases involved in the transduction of a variety of signals. There is increasing evidence to indicate that specific PKC isoforms are involved in the regulation of distinct cellular processes. In glioma cells, PKC alpha was found to be a critical regulator of proliferation and cell cycle progression, while PKC epsilon was found to regulate adhesion and migration. Herein, we report that specific PKC isoforms are able to differentially activate extracellular-signal regulated kinase (ERK) in distinct cellular locations: while PKC alpha induces the activation of nuclear ERK, PKC epsilon induces the activation of ERK at focal adhesions. Inhibition of the ERK pathway completely abolished the PKC-induced integrin-mediated adhesion and migration. Thus, we present the first evidence that PKC epsilon is able to activate ERK at focal adhesions to mediate glioma cell adhesion and motility, providing a molecular mechanism to explain the different biological functions of PKC alpha and epsilon in glioma cells.
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Affiliation(s)
- A Besson
- Department of Oncology, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
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Abstract
Human immunodeficiency virus (HIV), the retrovirus associated with acquired immune deficiency syndrome (AIDS), induces a spectrum of immune abnormalities including a state of anergy in the host. This state is due to the binding of HIV envelope glycoprotein moieties to CD4 molecules and chemokine receptors. Resulting decrease in antigen presenting cell function and the interference with functioning of positive and negative regulatory molecules involved in signal transduction have an anergizing effect on the immune system. This effect is exemplified by diminished production of interleukin-2 (IL-2) and interferon-gamma and reduced expression of IL-2 receptor by CD4 helper cells of HIV patients. These immune abnormalities lead to clinically relevant immunological phenomena such as Type-1 to Type-2 switch, decrease in delayed-type hypersensitivity dermal reaction, etc. Insight into these interesting phenomena could pave the path for favorably altering the immunological milieu for drug and vaccine trials.
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Affiliation(s)
- H R Hegde
- Department of Paediatrics, Peter Lougheed Centre, Health Science Centre, 3500-26 Avenue NE, Calgary, Alberta, TIY 6J4, Canada
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14
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Abstract
Human immunodeficiency virus (HIV), the retrovirus associated with acquired immune deficiency syndrome (AIDS), acts as a super-antigen by binding to the variable region of the beta (V beta) chain of T-cell receptor (TCR). It's binding to CD4 molecules and chemokine receptors induces a spectrum of immune abnormalities including 'a state of anergy' in the host. This state is due to a defective function of T-helper cell-1 (Th-1), a reduction in production of lymphokines required for signal transduction, an impaired cytotoxic cell activation and a decrease in antigen presenting function of monocyte-macrophage cell lineage. These immune abnormalities form the basis for severe opportunistic infections and malignancies in the host. Malnutrition, micronutrient abnormalities, concomitant infections and genetic factors, etc., are some of the compounding co-factors that further contribute to 'the state of anergy'.
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Affiliation(s)
- H R Hegde
- Department of Paediatrics, the University of Calgary and Peter Lougheed Centre, 3500-26 Avenue N.E, Calgary, Alberta, Canada T1Y 6J4
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15
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Abstract
Hck is a member of the Src-family of protein tyrosine kinases that appears to function in mature leukocytes to communicate a number of extracellular signals including various cytokines. In this study we show that the thiol-reactive heavy metal, mercuric chloride (HgCl2) induces rapid and robust activation of tyrosine phosphorylation within human myelomonocytic cells. This increase in tyrosine-phosphorylated proteins requires the activity of Hck because both kinase inactive alleles of Hck and pharmacological inhibitors selective for the Src-family kinases are able to abrogate the cellular response to HgCl2. Furthermore, ectopic expression of Hck in murine fibroblasts is able to confer HgCl2 responsiveness, as indicated by an increase in tyrosine-phosphorylated proteins to a normally nonresponsive cell line. Concomitant with the activation of Hck, there is a physical association of Hck with another cytoplasmic protein tyrosine kinase, Syk. The ability of HgCl2 to activate Src-family kinases such as Hck in hematopoietic cells may help explain why exposure to the heavy metal is associated with immune system dysfunction in rodents as well as humans.
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Affiliation(s)
- S M Robbins
- Departments of Oncology, Biochemistry and Molecular Biology, University of Calgary, Canada.
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16
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Abstract
The ephrins are membrane-tethered ligands for the Eph receptor tyrosine kinases, which play important roles in patterning of the nervous and vascular systems. It is now clear that ephrins are more than just ligands and can also act as signalling-competent receptors, participating in bidirectional signalling. We have recently shown that ephrin-A5 signals within caveola-like domains of the plasma membrane upon engagement with its cognate Eph receptor, leading to increased adhesion of the cells to fibronectin. Here we show that ephrin-A5 controls sequential biological events that are consistent with its role in neuronal guidance. Activation of ephrin-A5 induces an initial change in cell adhesion followed by changes in cell morphology. Both effects are dependent on the activation of beta1 integrin involving members of the Src family of protein tyrosine kinases. The prolonged activation of ERK-1 and ERK-2 is required for the change in cell morphology. Our work suggests a new role for class A ephrins in specifying the affinity of the cells towards various extracellular substrates by regulating integrin function.
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Affiliation(s)
- A Davy
- Departments of Oncology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
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17
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Arcellana-Panlilio MY, Egeler RM, Ujack E, Pinto A, Demetrick DJ, Robbins SM, Coppes MJ. Decreased expression of the INK4 family of cyclin-dependent kinase inhibitors in Wilms tumor. Genes Chromosomes Cancer 2000; 29:63-9. [PMID: 10918395 DOI: 10.1002/1098-2264(2000)9999:9999<::aid-gcc1006>3.0.co;2-l] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin-dependent kinase (CDK) inhibitors represented by the INK4 family (including p16(INK4a, CDKN2A), p15(INK4b, CDKN2B), p18(INK4c, CDKN2C), and p19(INK4d, CDKN2D)) are regulators of the cell cycle shown to be aberrant in many types of human cancer. We tested the hypothesis that these CDK inhibitors are a target for altered gene expression in Wilms tumor. Using RT-PCR, gene expression of the INK4 family was found to be decreased in 9 of 38 Wilms tumor samples obtained from the National Wilms Tumor Study Group (NWTSG) tissue bank. All the affected tumor samples were of favorable histology. Methylation-specific PCR revealed that methylation in the p16 promoter region may be responsible for altered expression. The incidence of loss of p16 expression may increase with increasing tumor stage, i.e., 1/10 (10%) with stage I/II FH Wilms tumor, 2/10 (20%) with stage III FH Wilms tumor, and 4/10 (40%) with stage IV FH Wilms tumor. Thus, determining the expression status of the INK4 family may have potential prognostic value in the management of Wilms tumor.
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Affiliation(s)
- M Y Arcellana-Panlilio
- Department of Oncology, University of Calgary, the Southern Alberta Cancer Research Group, the Alberta Children's Hospital and Tom Baker Cancer Center, Calgary, Alberta, Canada
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18
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Abstract
It is now clear that the plasma membrane is not homogeneous but contains specific subcompartments characterized by their unique lipid and protein composition. Based on their enrichment in various signaling molecules, these microcompartments are now recognized to be sites of localized signal transduction for several extracellular stimuli. At least two different types of microdomains can be identified, largely based on the presence or absence of the caveolin proteins. The generic name of caveolae-like domains is commonly used to refer to both domains indistinguishably. Although caveolin proteins were long thought to be absent from the brain, we have shown that the human neuroblastoma cell line LAN-1 expresses both caveolin-1 and caveolin-2. Basic fibroblast growth factor (FGF)-2 induced a specific signaling response within the caveolae-like domain of LAN-1 cells, characterized by the tyrosine phosphorylation of a 75-80-kDa protein. This protein present in the caveolae-like domains has properties suggesting that it is a member of the SNT family of adapter proteins. The signaling event originating in the caveolae-like domains in response to FGF-2 appeared to require the activation of at least Fyn and Lyn, two members of the Src family of tyrosine kinases. This work suggests that compartmentalized signaling within caveolae-like domains may create a level of specificity for certain growth factors such as FGF.
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Affiliation(s)
- A Davy
- Department of Oncology, University of Calgary, Alberta, Canada
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19
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Davy A, Gale NW, Murray EW, Klinghoffer RA, Soriano P, Feuerstein C, Robbins SM. Compartmentalized signaling by GPI-anchored ephrin-A5 requires the Fyn tyrosine kinase to regulate cellular adhesion. Genes Dev 1999; 13:3125-35. [PMID: 10601038 PMCID: PMC317175 DOI: 10.1101/gad.13.23.3125] [Citation(s) in RCA: 238] [Impact Index Per Article: 9.5] [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: 12/22/2022]
Abstract
Eph receptor tyrosine kinases and their corresponding surface-bound ligands, the ephrins, provide cues to the migration of cells and growth cones during embryonic development. Here we show that ephrin-A5, which is attached to the outer leaflet of the plasma membrane by a glycosyl-phosphatidylinositol-anchor, induces compartmentalized signaling within a caveolae-like membrane microdomain when bound to the extracellular domain of its cognate Eph receptor. The physiological response induced by this signaling event is concomitant with a change in the cellular architecture and adhesion of the ephrin-A5-expressing cells and requires the activity of the Fyn protein tyrosine kinase. This study stresses the relevance of bidirectional signaling involving the ephrins and Eph receptors during brain development.
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Affiliation(s)
- A Davy
- Departments of Oncology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N-4N1 Canada
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20
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Abstract
The level of phosphorylation within cells is tightly regulated by the concerted action of protein kinases and protein phosphatases [Hunter, T. (1995) Cell 80, 225-236]. Disregulation in the activity of either of these players can lead to cellular transformation. Many protein tyrosine kinases are proto-oncogenes and it has been postulated that some protein phosphatases may act as tumor suppressors. Herein we will review the recent findings addressing the roles the candidate tumor suppressor PTEN/MMAC1/TEP1 (PTEN, phosphatase and tensin homologue deleted from chromosome 10; MMAC 1, mutated in multiple advanced cancers 1; TEP1, TGF beta regulated and epithelial cell enriched phosphatase 1) plays in signal transduction and tumorigenesis. PTEN is a dual specificity protein phosphatase (towards phospho-Ser/Thr and phospho-Tyr) and, unexpectedly, also has a phosphoinositide 3-phosphatase activity. PTEN plays an important role in the modulation of the 1-phosphatidylinositol 3-kinase (PtdIns 3-kinase) pathway, by catalyzing the degradation of the PtdIns(3,4,5)P3 generated by PtdIns 3-kinase; this inhibits the downstream functions mediated by the PtdIns 3-kinase pathway, such as activation of protein kinase B (PKB, also known as Akt), cell survival and cell proliferation. Furthermore, PTEN modulates cell migration and invasion by negatively regulating the signals generated at the focal adhesions, through the direct dephosphorylation and inhibition of focal adhesion kinase (FAK). Growth factor receptor signaling is also negatively regulated by PTEN, through the inhibition of the adaptor protein Shc. While some of the functions of PTEN have been elucidated, it is clear that there is much more to discover about the roles of this unique protein.
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Affiliation(s)
- A Besson
- Department of Oncology, University of Calgary, Alberta, Canada
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21
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Howlett CJ, Bisson SA, Resek ME, Tigley AW, Robbins SM. The proto-oncogene p120(Cbl) is a downstream substrate of the Hck protein-tyrosine kinase. Biochem Biophys Res Commun 1999; 257:129-38. [PMID: 10092522 DOI: 10.1006/bbrc.1999.0427] [Citation(s) in RCA: 25] [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] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hematopoietic cell kinase (Hck) is a member of the Src-family of protein tyrosine kinases. We have found that upon enzymatic activation of Hck by the heavy metal mercuric chloride, there was a rapid increase in the levels of tyrosine phosphorylation of several proteins including the proto-oncogene p120(Cbl). Fibroblasts that are transformed with an activated allele of Hck exhibit constitutive Cbl phosphorylation. Upon Fcgamma receptor activation, a more physiologically relevant extracellular signal, Cbl is tyrosine phosphorylated and the Src-family selective inhibitor, PP1, can prevent this phosphorylation on Cbl. Hck phosphorylates Cbl in vitro and the interaction between Cbl and Hck is direct, requiring Hck's unique, SH3 and SH2 domains for optimal binding. Using a novel estrogen-regulated chimera of Hck we have shown a hormone-dependent association between Hck and Cbl in murine fibroblasts. This work suggests that Cbl serves as a key mediator of Hck induced signalling in hematopoietic cells.
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Affiliation(s)
- C J Howlett
- Department of Oncology, University of Calgary, Calgary, Alberta, Canada
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22
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Murray EW, Pihl C, Robbins SM, Prevost J, Mokashi A, Bloomfield SM, Brown CB. The soluble granulocyte-macrophage colony-stimulating factor receptor's carboxyl-terminal domain mediates retention of the soluble receptor on the cell surface through interaction with the granulocyte-macrophage colony-stimulating factor receptor beta-subunit. Biochemistry 1998; 37:14113-20. [PMID: 9760247 DOI: 10.1021/bi9802364] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 11/28/2022]
Abstract
The hematopoietic cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) mediates its activity through binding to cell-surface receptors. The high-affinity GM-CSF receptor (GMR) consists of two transmembrane-anchored subunits: a ligand-specific, low-affinity subunit (GMRalpha); and a signal-transducing beta-subunit (GMRbeta). The human GMRalpha subunit also exists in a soluble isoform (SOLalpha) which antagonizes GM-CSF activity in vitro. Previous studies by us have shown that coexpression of SOLalpha and a mutated GMRbeta in BHK cells results in retention of SOLalpha on the cell surface and the formation of an intermediate affinity binding complex (Kd approximately 300 pM). This paper investigates the mechanism of the retention of SOLalpha on the cell surface. The data demonstrate that SOLalpha is anchored by a direct, ligand-independent interaction with GMRbeta which also occurs when SOLalpha is coexpressed with wild-type GMRbeta. However, SOLalpha and wild-type GMRbeta form a complex which binds GM-CSF with high affinity (Kd = 39 pM), indistinguishable from the binding characteristics of the TMalpha/GMRbeta complex. The experiments further reveal that the interaction between SOLalpha and GMRbeta is abrogated by removal of the unique 16 amino acid carboxyl-terminal domain of SOLalpha. Specific mutation of cysteine 323 in this carboxyl-domain to alanine also eliminates the cell-surface retention of SOLalpha identifying this residue as being necessary for the formation of the SOLalpha/GMRbeta complex.
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Affiliation(s)
- E W Murray
- Alberta Bone Marrow Transplant Program and Cancer Biology Research Group, Department of Medicine, The University of Calgary, Alberta, Canada
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23
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Murray EW, Robbins SM. Antibody cross-linking of the glycosylphosphatidylinositol-linked protein CD59 on hematopoietic cells induces signaling pathways resembling activation by complement. J Biol Chem 1998; 273:25279-84. [PMID: 9737993 DOI: 10.1074/jbc.273.39.25279] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [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
CD59 is a glycosylphosphatidylinositol-anchored cell surface glycoprotein involved in protecting cells from host-mediated complement attack. Studies have shown that antibody cross-linking of CD59 induces a series of intracellular signaling events including the activation of protein-tyrosine kinases (PTK). To further characterize these events, antibodies and complement 8, one of the natural ligands of CD59, were used to activate CD59. Antibody-induced cross-linking of CD59 on the surface of THP-1 and U937 hematopoietic cell lines as well as exposure to complement 8 induces a rapid increase in the tyrosine phosphorylation of several proteins within the cell. Consistent with an early role for the Src family PTKs in these signaling events, we found that transient activation of Hck- and CD59-mediated signaling was abrogated in the presence of the Src family PTK-selective inhibitor PP1. Although the molecular mechanism by which CD59 communicates to Hck is unknown, cellular fractionation studies indicated that both CD59 and Hck are compartmentalized in plasma membrane microdomains. We also detected tyrosine phosphorylation of the adaptor proteins p120 and Shc, and the cytoplasmic nonreceptor tyrosine kinase Syk. The identification of CD59-mediated signaling events may help explain why paroxysmal nocturnal hemoglobinuria patients, who are deficient in glycosylphosphatidylinositol-linked proteins including CD59, are susceptible to proliferative disorders.
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Affiliation(s)
- E W Murray
- Cancer Biology and Immunology Research Groups, Departments of Oncology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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24
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Abstract
CD20 is a B cell integral membrane protein capable of initiating growth-modulating signals in human B lymphocytes upon its engagement with monoclonal anti-CD20 antibodies. In this report, we demonstrate that treatment of B cells with CD20 antibodies induces rapid redistribution of CD20 into a detergent-insoluble membrane compartment. Redistribution is detected as early as 15 s, following antibody addition, and involves up to 95% of CD20 molecules, depending on the antibody used. All of the detergent-insoluble CD20 was found in the low density fractions of sucrose density gradients, indicating that CD20 redistributes to glycolipid-rich membrane domains, analogous to caveolae in some cell types. As CD20 has previously been shown to associate with Src family tyrosine kinases, their co-existence in these compartments suggests a link to the role of CD20 in signal transduction. This study provides insight into the mechanism by which CD20 communicates signals to the cell interior and indicates that the search for membrane-proximal intracellular signaling partners should be directed to the Triton-insoluble fraction.
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Affiliation(s)
- J P Deans
- Immunology Research Group, Department of Medical Biochemistry, The University of Calgary, Calgary, Alberta T2N 4N1, Canada.
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25
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Robbins SM, Quintrell NA, Bishop JM. Myristoylation and differential palmitoylation of the HCK protein-tyrosine kinases govern their attachment to membranes and association with caveolae. Mol Cell Biol 1995; 15:3507-15. [PMID: 7791757 PMCID: PMC230587 DOI: 10.1128/mcb.15.7.3507] [Citation(s) in RCA: 196] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The human proto-oncogene HCK encodes two versions of a protein-tyrosine kinase, with molecular weights of 59,000 (p59hck) and 61,000 (p61hck). The two proteins arise from a single mRNA by alternative initiations of translation. In this study, we explored the functions of these proteins by determining their locations within cells and by characterizing lipid modifications required for the proteins to reach those locations. We found that p59hck is entirely associated with cellular membranes, including the organelles known as caveolae; in contrast, only a portion of p61hck is situated on membranes, and none is detectable in preparations of caveolae. These distinctions can be attributed to differential modification of the two HCK proteins with fatty acids. Both proteins are at least in part myristoylated, p59hck more so than p61hck. In addition, however, p59hck is palmitoylated on cysteine 3 in the protein. Palmitoylation of the protein requires prior myristoylation and, in turn, is required for targeting to caveolae. These findings are in accord with recent reports for other members of the SRC family of protein-tyrosine kinases. Taken together, the results suggest that HCK and several of its relatives may participate in the functions of caveolae, which apparently include the transduction of signals across the plasma membrane to the interior of the cell.
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Affiliation(s)
- S M Robbins
- Department of Microbiology, University of California, San Francisco 94143-0552, USA
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26
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Bishop JM, Capobianco AJ, Doyle HJ, Finney RE, McMahon M, Robbins SM, Samuels ML, Vetter M. Proto-oncogenes and plasticity in cell signaling. Cold Spring Harb Symp Quant Biol 1994; 59:165-71. [PMID: 7587066 DOI: 10.1101/sqb.1994.059.01.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- J M Bishop
- G.W. Hooper Research Foundation, University of California, San Francisco 94143-0552, USA
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27
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Finney RE, Robbins SM, Bishop JM. Association of pRas and pRaf-1 in a complex correlates with activation of a signal transduction pathway. Curr Biol 1993; 3:805-12. [PMID: 15335813 DOI: 10.1016/0960-9822(93)90214-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/1993] [Revised: 11/03/1993] [Accepted: 11/04/1993] [Indexed: 11/29/2022]
Abstract
BACKGROUND A key pathway for transduction of proliferative, developmental and oncogenic stimuli from receptors at the cell surface to transcription factors located in the nucleus involves the activation of pRas and pRaf-1. Recent publications have described a physical interaction between pRas and pRaf-1, either as ectopic proteins in yeast or as recombinant proteins added to cellular extracts. Until now, however, physical complexes that include pRas and pRaf-1 have not been identified as native structures in mammalian cells. RESULTS We have directly identified a pRas-pRaf-1 complex in extracts of mammalian cells. Formation of the complex is augmented in neoplastically transformed cells expressing constitutively activated pRas. Moreover, the complexes form in concert with the activation of pRas during intracellular signalling through the T-cell receptor in T-leukemia cells. CONCLUSIONS We propose that, pRas signals to pRaf-1 in vivo by means of a direct physical interaction that results in activation of the pRaf-1 protein kinase.
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Affiliation(s)
- R E Finney
- The George Williams Hooper Foundation, University of California, Box 0552, San Francisco, California 94143, USA
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28
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Robbins SM, Williams JG, Spiegelman GB, Weeks G. Cloning and characterization of the Dictyostelium discoideum rasG genomic sequences. Biochim Biophys Acta 1992; 1130:85-9. [PMID: 1339294 DOI: 10.1016/0167-4781(92)90467-e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A Dictyostelium discoideum genomic DNA clone containing the ras-related gene, rasG was isolated using the rasG cDNA as a probe. The genomic clone encompasses the entire coding region of the gene and 1.5 kb of 5' flanking region. The rasG gene contains a single intron as determined by sequence comparison with the cDNA, whereas the highly related rasD gene contains three introns. Primer extension analysis showed that transcription of the rasG gene initiates at multiple sites. Sequence analysis of the 5' flanking region of the gene revealed a stretch of thymine residues upstream from the transcription start sites but there is no evidence for a TATA box sequence.
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Affiliation(s)
- S M Robbins
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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29
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Abstract
Blind testing of 743 women who attended an inner-city hospital family-planning clinic showed 8 (1.1%) patients to have serum antibodies to human immunodeficiency virus type I (HIV-1). A retrospective chart survey did not show an association between HIV-1 antibody seropositivity and ethnicity, marital status, education, history of sexually transmitted diseases, drug and/or alcohol use, and contraceptive method. This failure to establish previously reported correlation may be a function of methods, sample size, or reflect a different population. Nonetheless, the seroprevalence the authors found shows that all patients in a family-planning clinic setting should be offered HIV-1 antibody testing.
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Affiliation(s)
- M R Spence
- Department of Obstetrics and Gynecology, Hahnemann University School of Medicine, Philadelphia, PA 19102
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30
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Abstract
Dictyostelium discoideum, like other eukaryotes, has been shown to express several ras-related genes. Two gene products, Ddras and DdrasG, are highly conserved relative to the human ras proteins. Ddras is expressed at the pseudoplasmodial stage of development, whereas DdrasG is expressed in vegetative cells and during early development. In addition, Dictyostelium possesses three ras-related genes, SAS1, SAS2 and Ddrap1, whose gene products are only partially conserved relative to those of the ras genes. The expression of these three genes is also developmentally regulated.
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Affiliation(s)
- S M Robbins
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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31
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Robbins SM, Suttorp VV, Weeks G, Spiegelman GB. A ras-related gene from the lower eukaryote Dictyostelium that is highly conserved relative to the human rap genes. Nucleic Acids Res 1990; 18:5265-9. [PMID: 2205839 PMCID: PMC332150 DOI: 10.1093/nar/18.17.5265] [Citation(s) in RCA: 34] [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] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The cellular slime mold Dictyostelium discoideum contains two ras genes, DdrasG and Ddras that are differentially expressed during development. We have characterized a gene that hybridized to both Ddras and DdrasG under low, but not under high stringency conditions. The deduced amino acid sequence is highly conserved with respect to the human rap (Krev-1, smg21) proteins and the corresponding gene has been designated Ddrap1. The Ddrap1 gene is expressed at all stages during development but is expressed maximally during the aggregation and culmination periods when the expression of Ddras and DdrasG is declining. During vegetative growth and early development Ddrap1 cDNA hybridizes to a single mRNA of 1.1 kb. As development progresses the level of this mRNA declines and messages of 1.0 and 1.3 kb appear.
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Affiliation(s)
- S M Robbins
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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32
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Kwong L, Xie YJ, Daniel J, Robbins SM, Weeks G. A Dictyostelium morphogen that is essential for stalk cell formation is generated by a subpopulation of prestalk cells. Development 1990; 110:303-10. [PMID: 2081467 DOI: 10.1242/dev.110.1.303] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [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: 11/20/2022]
Abstract
The stalk cell differentiation inducing factor (DIF) has the properties required of a morphogen responsible for pattern regulation during the pseudoplasmodial stage of Dictyostelium development. It induces prestalk cell formation and inhibits prespore cell formation, but there is as yet no strong evidence for a morphogenetic gradient of DIF. We have measured DIF accumulation by monolayers of isolated prestalk and prespore cells in an attempt to provide evidence for such a gradient. DIF is accumulated in the largest quantities by a subpopulation of prestalk cells that specifically express the DIF-inducible genes pDd56 and pDd26. Since it has been shown recently that cells that express pDd56 are localized in the central core of the prestalk cell region of the pseudoplasmodia, our current results suggest a morphogenetic gradient generated by this region.
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Affiliation(s)
- L Kwong
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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33
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Abstract
DdrasG gene expression during the early development of Dictyostelium discoideum has been examined in detail. The amount of DdrasG-specific mRNA increased approximately twofold during the first 2 to 3 h of development and then declined rapidly, reaching negligible levels by the aggregation stage. The increase in mRNA levels that occurred during the first 2 to 3 h of development also occurred during differentiation in cell suspensions and was enhanced when cells were shaken rapidly. This initial increase was unaffected by cell density. When cells were set up to differentiate on filters, the addition of a glucose-amino acid mixture slightly delayed differentiation and had a similar effect on the expression of the gene. The decline in DdrasG expression during development did not occur when cells were treated with cycloheximide, suggesting that the expression of a developmentally regulated gene product is essential for the reduction of DdrasG gene mRNA. There was no decrease in DdrasG mRNA level during differentiation in shake suspension, but the decrease did occur upon application of pulses of cyclic AMP to shaking cultures. The application of a continuously high level of cyclic AMP delayed the increase in expression of the gene and did not result in the subsequent decline. These results suggest that the induction of a functional cyclic AMP relay system is important in reducing DdrasG gene mRNA levels.
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Affiliation(s)
- M Khosla
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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34
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Robbins SM, Williams JG, Jermyn KA, Spiegelman GB, Weeks G. Growing and developing Dictyostelium cells express different ras genes. Proc Natl Acad Sci U S A 1989; 86:938-42. [PMID: 2644652 PMCID: PMC286594 DOI: 10.1073/pnas.86.3.938] [Citation(s) in RCA: 61] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The expression of ras-related protein in the cellular slime mold Dictyostelium discoideum is developmentally regulated. It was previously reported that Dictyostelium possesses a single ras gene (Ddras) that is maximally expressed during the pseudoplasmodial stage of development. We have isolated a series of cDNA clones derived from a second ras gene, DdrasG. It encodes a protein that is very similar to the protein encoded by Ddras, but in contrast to Ddras, DdrasG is only expressed during growth and early development. Although other eukaryotic organisms possess more than one ras gene, Dictyostelium is thus far unique in expressing different ras genes at different stages of development. In Dictyostelium the two ras proteins may fulfill different functions, with the DdrasG protein playing a role during cell growth and the Ddras protein playing a role in signal transduction during multicellular development.
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Affiliation(s)
- S M Robbins
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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Robbins SM, Tuten TU, Clements JL, Fekete P. Angiographic diagnosis of gastric volvulus with report of a complication following left gastric artery embolization. Gastrointest Radiol 1988; 13:112-4. [PMID: 3258835 DOI: 10.1007/bf01889038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Gastric volvulus is a rare cause of upper gastrointestinal (UGI) tract obstruction and may present as acute UGI hemorrhage. The angiographic findings of gastric volvulus are discussed and a report of a complication of embolization of the left gastric artery in unsuspected mesenteroaxial stomach volvulus is given.
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Affiliation(s)
- S M Robbins
- Department of Radiology, Grady Memorial Hospital, Atlanta, Georgia 30335
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Abstract
The ability of a T1-weighted spin-echo magnetic resonance (MR) sequence to allow differentiation of benign from malignant adrenal masses at 0.5 T was investigated in 28 patients with 35 adrenal masses. All nine lesions with an adrenal mass-liver signal intensity ratio of 0.71 or less were metastases, and all 15 with a ratio of 0.78 or more were adenomas. Eleven masses (31%)--including six adenomas, three metastases, a pheochromocytoma, and a neuroblastoma--had ratios between these values. Nine of ten masses with adrenal mass-fat intensity ratios of 0.35 or less were metastases, and all 12 with ratios of 0.42 or more were benign. Eleven masses (31%), four malignant and one benign, had ratios between these values. The ratios for two masses could not be calculated due to lack of fat. The specificity of T1-weighted MR imaging in differentiating benign from malignant adrenal masses appears similar to that reported for T2-weighted imaging. However, significant overlap occurred, as has also been reported for T2-weighted imaging. While both imaging sequences may help distinguish benign from malignant adrenal masses in some cases, biopsy is still necessary when an accurate histologic diagnosis is essential.
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Affiliation(s)
- J L Chezmar
- Department of Radiology, Emory University School of Medicine, Atlanta, GA 30322
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Robbins SM. Pulpal pathosis secondary to systemic cardiovascular disease. J Endod 1980; 6:650-1. [PMID: 6935373 DOI: 10.1016/s0099-2399(80)80167-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Robbins SM, Finklestein J. Reducing the emotional and economic costs of hospitalization of acutely ill asthmatics. Description of an improved emergency room program. Clin Pediatr (Phila) 1973; 12:550-4. [PMID: 4725683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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