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Huang S, Shahine A, Cheng TY, Chen YL, Ng SW, Balaji GR, Farquhar R, Gras S, Hardman CS, Altman JD, Tahiri N, Minnaard AJ, Ogg GS, Mayfield JA, Rossjohn J, Moody DB. CD1 lipidomes reveal lipid-binding motifs and size-based antigen-display mechanisms. Cell 2023; 186:4583-4596.e13. [PMID: 37725977 PMCID: PMC10591967 DOI: 10.1016/j.cell.2023.08.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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] [Received: 09/16/2021] [Revised: 05/05/2023] [Accepted: 08/21/2023] [Indexed: 09/21/2023]
Abstract
The CD1 system binds lipid antigens for display to T cells. Here, we solved lipidomes for the four human CD1 antigen-presenting molecules, providing a map of self-lipid display. Answering a basic question, the detection of >2,000 CD1-lipid complexes demonstrates broad presentation of self-sphingolipids and phospholipids. Whereas peptide antigens are chemically processed, many lipids are presented in an unaltered form. However, each type of CD1 protein differentially edits the self-lipidome to show distinct capture motifs based on lipid length and chemical composition, suggesting general antigen display mechanisms. For CD1a and CD1d, lipid size matches the CD1 cleft volume. CD1c cleft size is more variable, and CD1b is the outlier, where ligands and clefts show an extreme size mismatch that is explained by uniformly seating two small lipids in one cleft. Furthermore, the list of compounds that comprise the integrated CD1 lipidome supports the ongoing discovery of lipid blockers and antigens for T cells.
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Affiliation(s)
- Shouxiong Huang
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Adam Shahine
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Tan-Yun Cheng
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yi-Ling Chen
- Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK
| | - Soo Weei Ng
- Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK
| | - Gautham R. Balaji
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Rachel Farquhar
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Stephanie Gras
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Clare S. Hardman
- Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK
| | - John D. Altman
- Emory Vaccine Center, Emory School of Medicine, Atlanta, GA 30322, USA
| | - Nabil Tahiri
- Department of Chemical Biology, Stratingh Institute for Chemistry, Groningen, Netherlands
| | - Adriaan J. Minnaard
- Department of Chemical Biology, Stratingh Institute for Chemistry, Groningen, Netherlands
| | - Graham S. Ogg
- Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK
| | - Jacob A. Mayfield
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jamie Rossjohn
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Australian Research Council Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
- Institute of Infection and Immunity, Cardiff University, School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - D. Branch Moody
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Lead contact
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Farquhar R, Van Rhijn I, Moody DB, Rossjohn J, Shahine A. αβ T-cell receptor recognition of self-phosphatidylinositol presented by CD1b. J Biol Chem 2023; 299:102849. [PMID: 36587766 PMCID: PMC9900620 DOI: 10.1016/j.jbc.2022.102849] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
CD1 glycoproteins present lipid-based antigens to T-cell receptors (TCRs). A role for CD1b in T-cell-mediated autoreactivity was proposed when it was established that CD1b can present self-phospholipids with short alkyl chains (∼C34) to T cells; however, the structural characteristics of this presentation and recognition are unclear. Here, we report the 1.9 Å resolution binary crystal structure of CD1b presenting a self-phosphatidylinositol-C34:1 and an endogenous scaffold lipid. Moreover, we also determined the 2.4 Å structure of CD1b-phosphatidylinositol complexed to an autoreactive αβ TCR, BC8B. We show that the TCR docks above CD1b and directly contacts the presented antigen, selecting for both the phosphoinositol headgroup and glycerol neck region via antigen remodeling within CD1b and allowing lateral escape of the inositol moiety through a channel formed by the TCR α-chain. Furthermore, through alanine scanning mutagenesis and surface plasmon resonance, we identified key CD1b residues mediating this interaction, with Glu-80 abolishing TCR binding. We in addition define a role for both CD1b α1 and CD1b α2 molecular domains in modulating this interaction. These findings suggest that the BC8B TCR contacts both the presented phospholipid and the endogenous scaffold lipid via a dual mechanism of corecognition. Taken together, these data expand our understanding into the molecular mechanisms of CD1b-mediated T-cell autoreactivity.
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Affiliation(s)
- Rachel Farquhar
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Ildiko Van Rhijn
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA; Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - D Branch Moody
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Jamie Rossjohn
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Institute of Infection and Immunity, Cardiff University, School of Medicine, Cardiff, United Kingdom.
| | - Adam Shahine
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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3
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Reinink P, Shahine A, Gras S, Cheng TY, Farquhar R, Lopez K, Suliman SA, Reijneveld JF, Le Nours J, Tan LL, León SR, Jimenez J, Calderon R, Lecca L, Murray MB, Rossjohn J, Moody DB, Van Rhijn I. A TCR β-Chain Motif Biases toward Recognition of Human CD1 Proteins. J Immunol 2019; 203:3395-3406. [PMID: 31694911 DOI: 10.4049/jimmunol.1900872] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/09/2019] [Indexed: 12/30/2022]
Abstract
High-throughput TCR sequencing allows interrogation of the human TCR repertoire, potentially connecting TCR sequences to antigenic targets. Unlike the highly polymorphic MHC proteins, monomorphic Ag-presenting molecules such as MR1, CD1d, and CD1b present Ags to T cells with species-wide TCR motifs. CD1b tetramer studies and a survey of the 27 published CD1b-restricted TCRs demonstrated a TCR motif in humans defined by the TCR β-chain variable gene 4-1 (TRBV4-1) region. Unexpectedly, TRBV4-1 was involved in recognition of CD1b regardless of the chemical class of the carried lipid. Crystal structures of two CD1b-specific TRBV4-1+ TCRs show that germline-encoded residues in CDR1 and CDR3 regions of TRBV4-1-encoded sequences interact with each other and consolidate the surface of the TCR. Mutational studies identified a key positively charged residue in TRBV4-1 and a key negatively charged residue in CD1b that is shared with CD1c, which is also recognized by TRBV4-1 TCRs. These data show that one TCR V region can mediate a mechanism of recognition of two related monomorphic Ag-presenting molecules that does not rely on a defined lipid Ag.
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Affiliation(s)
- Peter Reinink
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584CL Utrecht, the Netherlands.,Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Adam Shahine
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Stephanie Gras
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Tan-Yun Cheng
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Rachel Farquhar
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Kattya Lopez
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115.,Socios en Salud Sucursal Peru, 15001 Lima, Peru
| | - Sara A Suliman
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Josephine F Reijneveld
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584CL Utrecht, the Netherlands.,Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115.,Stratingh Institute for Chemistry, University of Groningen, 9747AG Groningen, the Netherlands
| | - Jérôme Le Nours
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Li Lynn Tan
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | | | | | | | | | - Megan B Murray
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA 02115.,Division of Global Health Equity, Brigham and Women's Hospital, Boston, MA 02115.,Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115; and
| | - Jamie Rossjohn
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Institute of Infection and Immunity, School of Medicine, Cardiff University, CF14 4XN Cardiff, United Kingdom
| | - D Branch Moody
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Ildiko Van Rhijn
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584CL Utrecht, the Netherlands; .,Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
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Affiliation(s)
- M T Fox
- Department of Pathology and Infectious Diseases, Royal Veterinary College, University of London, Royal College Street, London NW1 0TU
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Veverka J, Thomas PC, Robinson M, Murchie S, Chapman C, Bell M, Harch A, Merline WJ, Bell JF, Bussey B, Carcich B, Cheng A, Clark B, Domingue D, Dunham D, Farquhar R, Gaffey MJ, Hawkins E, Izenberg N, Joseph J, Kirk R, Li H, Lucey P, Malin M, McFadden L, Miller JK, Owen WM, Peterson C, Prockter L, Warren J, Wellnitz D, Williams BG, Yeomans DK. Imaging of small-scale features on 433 Eros from NEAR: evidence for a complex regolith. Science 2001; 292:484-8. [PMID: 11313490 DOI: 10.1126/science.1058651] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
On 25 October 2000, the Near Earth Asteroid Rendevous (NEAR)-Shoemaker spacecraft executed a low-altitude flyover of asteroid 433 Eros, making it possible to image the surface at a resolution of about 1 meter per pixel. The images reveal an evolved surface distinguished by an abundance of ejecta blocks, a dearth of small craters, and smooth material infilling some topographic lows. The subdued appearance of craters of different diameters and the variety of blocks and different degrees of their burial suggest that ejecta from several impact events blanketed the region imaged at closest approach and led to the building up of a substantial and complex regolith consisting of fine materials and abundant meter-sized blocks.
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Affiliation(s)
- J Veverka
- Space Sciences Building, Cornell University, Ithaca, NY 14853, USA
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Veverka J, Robinson M, Thomas P, Murchie S, Bell JF, Izenberg N, Chapman C, Harch A, Bell M, Carcich B, Cheng A, Clark B, Domingue D, Dunham D, Farquhar R, Gaffey MJ, Hawkins E, Joseph J, Kirk R, Li H, Lucey P, Malin M, Martin P, McFadden L, Merline WJ, Miller JK. NEAR at eros: imaging and spectral results. Science 2000; 289:2088-97. [PMID: 11000105 DOI: 10.1126/science.289.5487.2088] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Eros is a very elongated (34 kilometers by 11 kilometers by 11 kilometers) asteroid, most of the surface of which is saturated with craters smaller than 1 kilometer in diameter. The largest crater is 5.5 kilometers across, but there is a 10-kilometer saddle-like depression with attributes of a large degraded crater. Surface lineations, both grooves and ridges, are prominent on Eros; some probably exploit planes of weakness produced by collisions on Eros and/or its parent body. Ejecta blocks (30 to 100 meters across) are abundant but not uniformly distributed over the surface. Albedo variations are restricted to the inner walls of certain craters and may be related to downslope movement of regolith. On scales of 200 meters to 1 kilometer, Eros is more bland in terms of color variations than Gaspra or Ida. Spectra (800 to 2500 nanometers) are consistent with an ordinary chondrite composition for which the measured mean density of 2.67 +/- 0.1 grams per cubic centimeter implies internal porosities ranging from about 10 to 30 percent.
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Affiliation(s)
- J Veverka
- Space Sciences Building, Cornell University, Ithaca, NY 14853, USA. Department of Geological Sciences, Northwestern University, 309 Locy Hall, Evanston, IL 60208, USA. Applied Physics Laboratory, Johns Hopkins University, 1110 Johns Hopkins Road, L
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7
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Veverka J, Thomas PC, Bell JF, Bell M, Carcich B, Clark B, Harch A, Joseph J, Martin P, Robinson M, Murchie S, Izenberg N, Hawkins E, Warren J, Farquhar R, Cheng A, Dunham D, Chapman C, Merline WJ, McFadden L, Wellnitz D, Malin M, Owen WM, Miller JK, Williams BG, Yeomans DK. Imaging of asteroid 433 eros during NEAR's flyby reconnaissance. Science 1999; 285:562-4. [PMID: 10417381 DOI: 10.1126/science.285.5427.562] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
During the 23 December 1998 flyby of asteroid 433 Eros, the Near-Earth Asteroid Rendezvous (NEAR) spacecraft obtained 222 images of Eros, as well as supporting spectral observations. The images cover slightly more than two-thirds of Eros (best resolution is approximately 400 meters per pixel) and reveal an elongated, cratered body with a linear feature extending for at least 20 kilometers. Our observations show that Eros has dimensions of 33 x 13 x 13 kilometers. The volume, combined with the mass determined by the NEAR radio science experiment, leads to a density of 2.5 +/- 0.8 grams per cubic centimeter. This relatively high density, and the presence of an extensive linear feature, suggest that Eros may be a structurally coherent body.
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Affiliation(s)
- J Veverka
- Space Sciences Building, Cornell University, Ithaca, NY 14853, USA. Department of Geological Sciences, Northwestern University, 309 Locy Hall, Evanston, IL 60208, USA. Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA. Sou
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8
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Abstract
One possible route to the evaluation of gene function is a quantitative approach based on the concepts of metabolic control analysis (MCA). An important first step in such an analysis is to determine the effect of deleting individual genes on the growth rate (or fitness) of S. cerevisiae. Since the specific growth-rate effects of most genes are likely to be small, we employed competition experiments in chemostat culture to measure the proportion of deletion mutants relative to that of a standard strain by using a quantitative PCR method. In this paper, we show that both densitometry and GeneScan analysis can be used with similar accuracy and reproducibility to determine the proportions of (at least) two strains simultaneously, in the range 10-90% of the total cell population. Furthermore, we report on a model competition experiment between two diploid nuclear petite mutants, homozygous for deletions in the cox5a or pet191 genes, and the standard strain (ho::kanMX4/ho::kanMX4) in chemostat cultures under six different physiological conditions. The results indicate that competition experiments is continuous culture are a suitable method to distinguish quantitatively between deletion mutants that qualitatively exhibit the same phenotype.
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Affiliation(s)
- F Baganz
- Department of Biomolecular Sciences, UMIST, Manchester, U.K
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Veverka J, Thomas P, Harch A, Clark B, Bell JF, Carcich B, Joseph J, Chapman C, Merline W, Robinson M, Malin M, McFadden LA, Murchie S, Hawkins SE, Farquhar R, Izenberg N, Cheng A. NEAR's flyby of 253 mathilde: images of a C asteroid. Science 1997; 278:2109-14. [PMID: 9405344 DOI: 10.1126/science.278.5346.2109] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
On 27 June 1997, the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew within 1212 kilometers of asteroid 253 Mathilde. Mathilde is an irregular, heavily cratered body measuring 66 kilometers by 48 kilometers by 46 kilometers. The asteroid's surface is dark (estimated albedo between 0.035 and 0.050) and similar in color to some CM carbonaceous chondrites. No albedo or color variations were detected. The volume derived from the images and the mass from Doppler tracking of the spacecraft yield a mean density of 1.3 +/- 0.2 grams per cubic centimeter, about half that of CM chondrites, indicating a porous interior structure.
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Affiliation(s)
- J Veverka
- J. Veverka, P. Thomas, A. Harch, B. Clark, J. F. Bell III, B. Carcich, J. Joseph, Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853, USA. C. Chapman and W. Merline, Southwest Research Institute, 1050 Walnut Str
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Sadovnick AD, Remick RA, Allen J, Swartz E, Yee IM, Eisen K, Farquhar R, Hashimoto SA, Hooge J, Kastrukoff LF, Morrison W, Nelson J, Oger J, Paty DW. Depression and multiple sclerosis. Neurology 1996; 46:628-32. [PMID: 8618657 DOI: 10.1212/wnl.46.3.628] [Citation(s) in RCA: 308] [Impact Index Per Article: 11.0] [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: 01/31/2023] Open
Abstract
The objective of the present study were (1) to ascertain the lifetime risk of a depression in a representative group of multiple sclerosis (MS) patients, (2) to assess the morbidity risks for depression among first-degree relatives of these MS patients, and (3) to compare these familial risks for first-degree relatives of MS patients with those for first-degree relatives of a primary depression population, i.e., depression but no MS. We psychiatrically evaluated 221 MS patients (index cases) using a structured clinical interview for the DSM-III-R and calculated the rate and lifetime risk of depression for these index cases using the product limit estimate of survival function. We obtained psychiatric histories for all first-degree relatives of index cases, and we calculated morbidity risks for depression for these relatives using the maximum likelihood approach and compared the risks using the likelihood ratio tests. Index cases had a 50.3% lifetime risk of depression. Morbidity risks for depression among first-degree relatives of index cases were decidedly lower when compared with morbidity risks among first-degree relatives of the reference population. Although there appears to be a very high rate of depression among MS patients, the data for their first-degree relatives do not support a clear genetic basis for this depression, or at least the same genetic basis that probably operates within families when depression occurs in the absence of MS.
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Affiliation(s)
- A D Sadovnick
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
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Abstract
The possible role of changes in presynaptic inhibition of muscle spindle primary afferent terminals in Parkinson's disease was investigated. The pathway from tibialis anterior Ia afferents to soleus Ia terminals was assessed in 20 patients with Parkinson's disease and in 17 age matched controls, both at rest and during maintenance of tonic plantar flexing torques about the ankle. At all torques less presynaptic inhibition was present in the patients with Parkinson's disease than in the controls. The difference was significant at rest (p < 0.03) and at 2 Nm (p < 0.05) but not at 5 Nm and 7 Nm torque. The amount of presynaptic inhibition did not change with torque in either group. The observed alteration in presynaptic inhibition in Parkinson's disease is likely to make only a small contribution to the rigidity and impaired movement control.
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Sadovnick AD, Eisen K, Hashimoto SA, Farquhar R, Yee IM, Hooge J, Kastrukoff L, Oger JJ, Paty DW. Pregnancy and multiple sclerosis. A prospective study. Arch Neurol 1994; 51:1120-4. [PMID: 7980107 DOI: 10.1001/archneur.1994.00540230058013] [Citation(s) in RCA: 71] [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] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE To conduct a prospective assessment of pregnancy on women with multiple sclerosis (MS), focusing on pregnancy outcome and relapses during gestation and up to 6 months after delivery. DESIGN Expected numbers of relapses were based on data for (1) "self-controls": the mothers ("cases") themselves prior to becoming pregnant and (2) "matched controls": female patients with MS "matched" to the mothers for year of birth, age of MS onset, MS type, MS course, and initial MS symptom(s). SETTING Cases and controls were identified from an ambulatory care MS clinic that serves the province of British Columbia, Canada. PATIENTS OR OTHER PARTICIPANTS Women with a diagnosis of MS who attended the MS clinic during 1982 through 1986 and subsequently became pregnant during 1982 through 1989 inclusive were included in this study as cases. Matched controls were women with MS who attended the MS clinic during the same period but did not become pregnant. RESULTS No significant increase in relapse rate was found for cases during the first two trimesters of gestation. The number of relapses was significantly less than expected during the third trimester compared with matched controls (chi 2 = 6.80, df = 1, P < .02), but not compared with self-controls (chi 2 = 3.39, df = 1, P > .05). The observed number of relapses for the 6 months after delivery did not differ significantly from expected (self-controls: chi 2 = 2.84, df = 2, P > .05; matched controls: chi 2 = 1.76, df = 2, P > .05). CONCLUSION These data suggest that neither pregnancy nor the 6-month period after delivery is a risk factor for relapse in MS. They are consistent with previous observations that, in the long term, pregnancy does not influence subsequent MS disability.
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Affiliation(s)
- A D Sadovnick
- Multiple Sclerosis Clinic, Vancouver Hospital and Health Sciences Centre
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13
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Luz JM, Markus H, Farquhar R, Schultz LD, Ellis RW, Freedman RB, Tuite MF. Expression and secretion of human protein disulphide isomerase in Saccharomyces cerevisiae. Biochem Soc Trans 1994; 22:76S. [PMID: 8206308 DOI: 10.1042/bst022076s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- J M Luz
- Biological Laboratory, University of Kent at Canterbury, U.K
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14
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Butchart P, Farquhar R, Part NJ, Roberts RC. The effect of age and voluntary contraction on presynaptic inhibition of soleus muscle Ia afferent terminals in man. Exp Physiol 1993; 78:235-42. [PMID: 8385962 DOI: 10.1113/expphysiol.1993.sp003683] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [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: 01/30/2023]
Abstract
Transmission in a pathway mediating presynaptic inhibition of soleus Ia afferent terminals was assessed from the reduction of soleus muscle H reflex amplitude brought about by a short conditioning vibration pulse applied to the anterior tibialis muscle. In a group of young subjects (aged between 21 and 37 years) the mean reduction in reflex size with the limb relaxed was to 29.2% of control, whereas in a group of older subjects (aged between 59 and 74 years) the reduction was significantly less, to 55.0% of control (P < 0.001, Student's t test). In the younger group the amount of presynaptic inhibition elicited was inversely related to the plantar-flexor torque produced by tonic contraction of gastrocnemius-soleus; often at higher torques no reduction in reflex size was seen. In contrast the older group showed only a slight reduction in presynaptic inhibition with increasing torque, so that at torques of 5 and 7 N m the amount of presynaptic inhibition elicited was similar in the younger and older groups. The older subjects were not able to sustain the higher torques produced by the younger subjects. These results suggest that the control of transmission in this spinal pathway changes with increasing age.
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Affiliation(s)
- P Butchart
- Department of Medicine, The University, Dundee
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Studney D, Lublin F, Marcucci L, Farquhar R, Redekop K, Nelson J, Paty DW. MS COSTAR: A Computerized Record for Use in Clinical Research in Multiple Sclerosis. Neurorehabil Neural Repair 1993. [DOI: 10.1177/136140969300700309] [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: 11/16/2022]
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Farquhar R, Honey N, Murant SJ, Bossier P, Schultz L, Montgomery D, Ellis RW, Freedman RB, Tuite MF. Protein disulfide isomerase is essential for viability in Saccharomyces cerevisiae. Gene 1991; 108:81-9. [PMID: 1761235 DOI: 10.1016/0378-1119(91)90490-3] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.9] [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: 12/28/2022]
Abstract
Protein disulfide isomerase (PDI) is an enzyme involved in the catalysis of disulfide bond formation in secretory and cell-surface proteins. Using an oligodeoxyribonucleotide designed to detect the conserved 'thioredoxin-like' active site of vertebrate PDIs, we have isolated a gene encoding PDI from the lower eukaryote, Saccharomyces cerevisiae. The nucleotide sequence and deduced open reading frame of the cloned gene predict a 530-amino-acid (aa) protein of Mr 59,082 and a pI of 4.1, physical properties characteristic of mammalian PDIs. Furthermore, the aa sequence shows 30-32% identity with mammalian and avian PDI sequences and has a very similar overall organisation, namely the presence of two approx. 100-aa segments, each of which is repeated, with the most significant homologies to mammalian and avian PDIs being in the regions (a, a') that contain the conserved 'thioredoxin-like' active site. The N-terminal region has the characteristics of a cleavable secretory signal sequence and the C-terminal four aa (-His-Asp-Glu-Leu) are consistent with the protein being a component of the S. cerevisiae endoplasmic reticulum. Transformants carrying multiple copies of this gene (designated PDI1) have tenfold higher levels of PDI activity and overproduce a protein of the predicted Mr. The PDI1 gene is unique in the yeast genome and encodes a single 1.8-kb transcript that is not found in stationary phase cells. Disruption of the PDI1 gene is haplo-lethal indicating that the product of this gene is essential for viability.
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Affiliation(s)
- R Farquhar
- Biological Laboratory, University of Kent, Canterbury, U.K
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Abstract
1. The effects of intravenous infusion of the direct acting muscle relaxant, dantrolene sodium (5 mg kg-1), on tension, integrated EMG, soleus muscle motor unit discharge frequency and gamma nerve fibre discharge were measured in the decerebrate rat. 2. Dantrolene sodium did not have any detectable direct effect upon the discharge of the gamma nerve fibres. 3. The soleus muscle of the decerebrate preparations exhibited spontaneous tension and reflex responses. 4. With the muscle held at constant length, dantrolene sodium caused an increase in the integrated EMG in 15 out of 18 experiments and a decrease in muscle tension in 15 out of 17. The results from these experiments showed great variability. 5. Dantrolene sodium caused a slight reduction in the tension response to tonic stretch; this was accompanied by an increase in the integrated EMG. 6. Dantrolene sodium also caused a shift in the relationship between tension and integrated EMG during the phasic component of the stretch reflex, with a greater integrated EMG being associated with a reduced tension. 7. Motor unit discharge frequencies were found to increase but not sufficiently to overcome the action of dantrolene sodium. It is concluded that motor unit recruitment must play an important role in the compensation for the muscle weakening action of dantrolene sodium.
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Affiliation(s)
- R Farquhar
- Department of Physiology, University of Dundee
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Abstract
The spoIVC locus of Bacillus subtilis was analysed. Fourteen spoIVC mutants isolated following nitrosoguanidine mutagenesis were used along with two previously characterized spoIVC mutants to construct a fine structure genetic map of the locus. The recombination index (RI) measured between extreme mutations was 0.26; no recombination could be detected between four of the mutations. Complementation analysis showed that all the mutations fall into two cistrons. The RI between extreme mutations in cistron A was about 0.17 and that between extreme mutations in cistron B was about 0.05. In respect of biochemical markers, the spoIVC mutations all produced similar phenotypes, irrespective of their location. However, in both cistrons oligosporogenous and asporogenous mutations mapped close together.
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Affiliation(s)
- R Farquhar
- Department of Biochemistry, University of Oxford, UK
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Farquhar R, Leslie GC, Part NJ. How is ventilation maintained in the presence of the muscle relaxant, dantrolene sodium? A study in the anaesthetized rat. Br J Pharmacol 1986; 88:79-86. [PMID: 3708226 PMCID: PMC1917100 DOI: 10.1111/j.1476-5381.1986.tb09473.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The effects of intravenous injection of the muscle relaxant dantrolene sodium on ventilation, integrated EMG of external intercostal muscles and motor unit discharge in these muscles were measured in anaesthetized rats. Dantrolene sodium was administered in a carrier solution at pH 10. The carrier was not responsible for the effects seen on dantrolene sodium infusion. Dantrolene sodium (5 mg kg-1 body weight) reduced inspired ventilation (VI) on average from 308 +/- 106 ml min-1 (s.d., n = 8) in the control period to 247 +/- 118 ml min-1 (n = 8) after dantrolene sodium. Expired ventilation was reduced likewise from 274 +/- 132 ml min-1 (n = 8) to 229 +/- 109 ml min-1 (n = 8). These changes are significant at P less than 0.05. The integrated EMG was increased by 40.0 +/- 29.3% (n = 9), a change significant at P less than 0.001. Dantrolene sodium not only decreased the mean interspike interval of individual motor units by 16.2 +/- 11.1% (n = 13), a change significant at P less than 0.001, but also increased the duration of the burst of activity of each individual motor unit on average by 36.2 +/- 52.4% (n = 13), a change significant at P less than 0.05. The recruitment of additional motor units was also effected by dantrolene sodium. These units did not behave in any noticeably different manner from units previously active. It is concluded that the nervous system compensates for the effect of dantrolene sodium only to a limited extent by increasing the frequency of discharge of active motor units. Recruitment ofadditional motor units and increased burst duration play at least as important a role.
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