Dr Jim Ralphs
Senior Lecturer
- ralphs@cardiff.ac.uk
- +44 (0)29 2087 4954
- Fax:
- +44 (0)29 2087 4486
- Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX
Biography
Publications
2023
- Koudouna, E., Young, R. D., Quantock, A. J. and Ralphs, J. R. 2023. Developmental changes in patterns of distribution of fibronectin and tenascin-C in the chicken cornea: evidence for distinct and independent functions during corneal development and morphogenesis. International Journal of Molecular Sciences 24(4), article number: 3555. (10.3390/ijms24043555)
2021
- Ashworth, S. et al. 2021. Chondroitin sulfate as a potential modulator of the stem cell niche in cornea. Frontiers in Cell and Developmental Biology 8, article number: 567358. (10.3389/fcell.2020.567358)
2020
- Young, R. D. et al. 2020. Observations on nascent matrix structures in embryonic cornea: Important in cell interactions, or merely vestiges of the lens surface?. Archives of Clinical and Experimental Ophthalmology 2(2), pp. 67-72. (10.46439/ophthalmology.2.014)
2019
- Young, R. D. et al. 2019. Cell-independent matrix configuration in early corneal development. Experimental Eye Research 187, article number: 107772. (10.1016/j.exer.2019.107772)
2018
- Feneck, E. M., Lewis, P. N., Ralphs, J. and Meek, K. M. 2018. A comparative study of the elastic fibre system within the mouse and human cornea. Experimental Eye Research 177, pp. 35-44. (10.1016/j.exer.2018.07.024)
- Feneck, E. M., Lewis, P. N., Ralphs, J. and Meek, K. M. 2018. A comparative study of the mouse and human corneal elastic system [Abstract]. Investigative Ophthalmology & Visual Science 59(9), article number: 5722.
- Jähn, K., Mason, D., Ralphs, J., Evans, B., Archer, C., Richards, R. G. and Stoddart, M. 2018. Phenotype and viability of MLO-Y4 cells Is maintained by TGFβ3 in a serum-dependent manner within a 3D-co-culture with MG-63 cells. International Journal of Molecular Sciences 19(7), article number: 1932. (10.3390/ijms19071932)
2015
- Beckett, M. C., Ralphs, J. R., Caterson, B. and Hayes, A. J. 2015. The transmembrane heparan sulphate proteoglycan syndecan-4 is involved in establishment of the lamellar structure of the annulus fibrosus of the intervertebral disc. European Cells and Materials 30, pp. 69-88.
2014
- Vazquez, M., Evans, B. A. J., Riccardi, D., Evans, S. L., Ralphs, J. R., Dillingham, C. M. and Mason, D. J. 2014. A new method to investigate how mechanical loading of osteocytes controls osteoblasts. Frontiers in Endocrinology 5, article number: 208. (10.3389/fendo.2014.00208)
- Czekanska, E. M., Ralphs, J. R., Alini, M. R. and Stoddart, M. 2014. Enhancing inflammatory and chemotactic signals to regulate bone regeneration. European Cells and Materials 28, pp. 320-334. (10.22203/eCM)
- Czekanska, E. M., Stoddart, M. J., Ralphs, J. R., Richards, R. G. and Hayes, J. S. 2014. A phenotypic comparison of osteoblast cell lines versus human primary osteoblasts for biomaterials testing. Journal of Biomedical Materials Research Part A 102(8), pp. 2636-2643. (10.1002/jbm.a.34937)
- Vazquez, M., Evans, B., Evans, S., Ralphs, J., Riccardi, D. and Mason, D. 2014. Development of a novel in vitro 3D osteoblast-osteocyte co-culture model to investigate mechanically-induced signalling. International Journal of Experimental Pathology 95(3), pp. A34-A35. (10.1111/iep.12078)
- Young, R. D. et al. 2014. Three-dimensional aspects of matrix assembly by cells in the developing cornea. Proceedings of the National Academy of Sciences 111(2), pp. 687-692. (10.1073/pnas.1313561110)
2011
- Vazquez, M., Evans, B. A. J., Ralphs, J. R., Riccardi, D. and Mason, D. J. 2011. Bone in vitro 3D osteoblast-osteocyte co-culture model. International Journal of Experimental Pathology 92(6), pp. A18-A18. (10.1111/j.1365-2613.2011.00780.x)
- Hayes, A. J., Hughes, C. E., Ralphs, J. R. and Caterson, B. 2011. Chondroitin sulphate sulphation motif expression in the ontogeny of the intervertebral disc. European Cells and Materials 21, pp. 1-14.
- Hayes, A. J. and Ralphs, J. R. 2011. The response of foetal annulus fibrosus cells to growth factors: modulation of matrix synthesis by TGF-β1 and IGF-1. Histochemistry and Cell Biology 136(2), pp. 163-175. (10.1007/s00418-011-0835-x)
- Hayes, A. J., Isaacs, M. D., Hughes, C. E., Caterson, B. and Ralphs, J. R. 2011. Collagen fibrillogenesis in the development of the annulus fibrosus of the intervertebral disc. European Cells and Materials 22, pp. 226-241.
2010
- Edwards, G. O., Coakley, W. T., Ralphs, J. R. and Archer, C. W. 2010. Modelling condensation and initiation of chondrogenesis in chick wing bud mesenchymal cells levitated in an ultrasound trap. European Cells & Materials 19, pp. 1-12. (10.1007/s10565-009-9123-0)
- Ralphs, J. R., Caterson, B., Hughes, C. E. and Hayes, A. J. 2010. Chondroitin sulphate sulfation motifs in intervertebral disc development [Abstract]. European Cells and Materials 20(Supp 2), pp. 3.
2009
- De Wreede, R. and Ralphs, J. R. 2009. Deposition of collagenous matrices by tendon fibroblasts in vitro: a comparison of fibroblast behavior in pellet cultures and a novel three-dimensional long-term scaffoldless xulture system. Tissue Engineering Part A 15(9), pp. 2707-2715. (10.1089/ten.tea.2008.0182)
- Gealy, E. C., Hayes, A. J., Buckwell, R., Young, R. D., Caterson, B., Quantock, A. J. and Ralphs, J. R. 2009. Actin and type I collagen propeptide distribution in the developing chick cornea. Investigative Ophthalmology & Visual Science 50(4), pp. 1653 -1658. (10.1167/iovs.08-2554)
2008
- Mason, D., Dillingham, C. M., Evans, B. A., Brakspear, K. S. and Ralphs, J. R. 2008. A 3D culture system to investigate osteocyte control of osteoblasts. Bone 42(Suppl), pp. S26-S27. (10.1016/j.bone.2007.12.033)
2007
- Young, R. D., Gealy, E. C., Liles, M., Caterson, B., Ralphs, J. R. and Quantock, A. J. 2007. Keratan sulfate glycosaminoglycan and the association with collagen fibrils in rudimentary lamellae in the developing avian cornea. Investigative Ophthalmology and Visual Science 48(7), pp. 3083-3088. (10.1167/iovs.06-1323)
- Malic, S., Hill, K. E., Ralphs, J. R., Hayes, A. J., Thomas, D. W., Potts, A. J. C. and Williams, D. W. 2007. Characterisation of Candida albicans infection of an in vitro oral epithelial model using confocal laser scanning microscopy. Oral Microbiology And Immunolology 22(3), pp. 188-194. (10.1111/j.1399-302X.2007.00344.x)
- Alini, M. et al. 2007. Are animal models useful for studying human disc disorders/degeneration?. European Spine Journal 17(1), pp. 2-19. (10.1007/s00586-007-0414-y)
- Gealy, E. C. et al. 2007. Differential expression of the keratan sulphate proteoglycan, keratocan, during chick corneal embryogenesis. Histochemistry and Cell Biology 128(6), pp. 551-555. (10.1007/s00418-007-0332-4)
2006
- Gealy, E. C., Buckwell, B., Caterson, B., Quantock, A. J. and Ralphs, J. R. 2006. Association between the cytoskeleton and collagen secretion in the developing cornea [Abstract]. International Journal of Experimental Pathology 87(1), pp. A43-A44. (10.1111/j.0959-9673.2006.00458.x)
2005
- Bazou, D., Foster, G. A., Ralphs, J. R. and Coakley, W. T. 2005. Erratum. Molecular Membrane Biology 22(4), pp. 373-373. (10.1080/09687860500315443)
- Bazou, D., Foster, G. A., Ralphs, J. R. and Coakley, W. T. 2005. Molecular adhesion development in a neural cell monolayer forming in an ultrasound trap. Molecular Membrane Biology 22(3), pp. 229-240. (10.1080/09687860500093396)
- Khan, I. M., Oldfield, S. F., Richardson, K., Ralphs, J. R. and Archer, C. W. 2005. Growth characteristics of chondroprogenitor cells in vitro. European Cells and Materials 10(Supp 2), pp. 67-67.
2002
- Lloyd, D., Ralphs, J. R. and Harris, J. C. 2002. Hydrogen production in Giardia intestinalis, a eukaryote with no hydrogenosomes. Trends in Parasitology 18(4), pp. 155-156. (10.1016/S1471-4922(01)02174-2)
2001
- Hayes, A. J., Benjamin, M. and Ralphs, J. R. 2001. Extracellular matrix in development of the intervertebral disc. Matrix Biology 20(2), pp. 107-121. (10.1016/S0945-053X(01)00125-1)
1999
- Hayes, A. J., Benjamin, M. and Ralphs, J. R. 1999. Role of actin stress fibres in the development of the intervertebral disc: cytoskeletal control of extracellular matrix assembly. Developmental Dynamics 215(3), pp. 179-189. (10.1002/(SICI)1097-0177(199907)215:3<179::AID-AJA1>3.0.CO;2-Q)
- Lloyd, D., Hayes, A. J. and Ralphs, J. R. 1999. Confocal laser scanning microscopy of environmental samples. In: Edwards, C. ed. Environmental Monitoring of Bacteria., Vol. 12. USA: Springer, pp. 251-265., (10.1385/0-89603-566-2:251)
1997
- Hayes, A. J., Ralphs, J. R. and Benjamin, M. 1997. The involvement of actin in annulus formation in the rat lumbar intervertebral disc. Journal of Anatomy 191(1), pp. 125.
1996
- Lloyd, D., Williams, A. G., Amann, R., Hayes, A. J., Durrant, L. and Ralphs, J. R. 1996. Intracellular prokaryotes in rumen ciliate protozoa: detection by confocal laser scanning microscopy after in situ hybridization with fluorescent 16S rRNA probes. European Journal of Protistology 32(4), pp. 523-531. (10.1016/S0932-4739(96)80011-3)
Cellular control of extracellular matrix secretion and organisation in connective tissues
The function of connective tissues depends on the organisation of their collagen fibres, arranged in parallel fibres, in parallel sheets (lamellae; annulus fibrosus, cornea, bone), or with more complex or random, orientation (cartilage, dermis, loose connective tissue).
My research is on roles of the cytoskeleton and cell-cell interactions in control of secretion and orientation of the extracellular matrix in fibrous connective tissues.
In tendons, longitudinal rows of fibroblasts are embedded between parallel collagen fibre bundles. Along a row, cells are connected by gap junctions made of connexins 43 and 32, and by adherens junctions. The adherens junctions link short lengths of actin stress fibres end to end from cell to cell along the cell row.
Gap junctions modulate cell response to load: antisense downregulation of of connexin 43 enhances, and connexin 32 depresses, matrix secretion. Adherens junction and stress fibre components are upregulated by load suggesting that cells may bind together more strongly; cell-cell junctions involving cadherins could also be involved in mechanosensation and thus initiation of load responses.
The annulus fibrosus consists of concentric collagenous lamellae linking vertebral bodies in the spine. In successive lamellae collagen fibres are tilted, forming a radial ply structure. The cornea has a similar organisation, although with thinner, more numerous lamellae In the annulus, oriented matrix deposition is preceded by orientation of fibroblasts into parallel sheets, with the long axis of the fibroblasts in each layer showing the same alternating angle as the collagen in the lamellae. The orientation process is associated with cadherin based cell-cell interactions, some gap junction expression and the development of prominent longitudinal actin stress fibres in the fibroblasts. In new studies, we are investigating possible associations between the collagen secretory pathway and prominent actin fibres in corneaL stromal fibroblasts, and early stage interactions between connective tissue cells.
Current sources of funding
Medlink/Health Technology Devices Programme
- Mesenchymal progenitor cells in allogeneic orthopaedic tissue engineering (with Prof CW Archer and Smith and Nephew plc, York)
- £509,566
- 2003-2006
BBSRC
- Developmental dynamics, cell-cell and cell-matrix interactions in the avian corneal stroma (with Dr AJ Quantock and Prof B Caterson)
- £310,000
- 2004-2007
BBSRC
- Progression of animal cell interactions and intra-cellular processes triggered on contact in ultrasound standing wave traps (with Prof WT Coakley and Prof CW Archer)
- £407,000
- 2005-8