Prof. Dr. med. Richard H.W. Funk
Project "neurons, retina and eye"
The findings in the retinal vessels lead us to the question, what is happening in retinae impaired by metabolic changes – similar to the situation found in patients and older people (age –changes) – with a special focus on the neurons.
Here, we (Dr. Knels, Dr. Röhlecke, Dr. Valtink with students and partners from other institutions) concentrated on the
a) most vulnerable cells in the retina: the retinal ganglion cell (RGC), photoreceptors and retinal pigment epithelium (RPE)
b) on oxidative and glycosylation damage by H2O2 and glyoxal (see below [2, 4, 6]).
First, we wanted to classify the signs (indicators) of cell stress with various methods and techniques (Raman spectroscopy [12], light spectroscopy [13] and many dyes indicating the functional state of cells [4, 8] and the retina [3]). The phenomena after cell stress which we found in vitro or in ex vivo whole mounts resemble those normally occuring in aged tissue: in RGC many transport processes within the cell were impaired (like in Alzheimers disease and like changes see after cross liking of proteins by advances glycation endproducts, AGEs [2]) and signs of energetic losses (mitochondrial defects [3, 4]) could be observed.
A PhD student (Paco Pan-Montojo) brought an interesting idea to this cell stress research in my lab: transduction of damaged proteins via autonomic nerves from the nerve plexus of the intestine to the central nerve system. He could finally show in mice that ingestion of the pesticide rotenone (inhibitor of the mitochondrial respiratory chain) lead to a pattern of pathological changes which is also found in human pathology of Parkinsons disease [1, 15, 18].
Another stress factor for retinal tissues which is “buzzed” today is the impact of blue light or more generally higher energetic, shortwave light [5, 7, 8]. Here, we tried to differentiate the wavelengths and the intensities in correlation to the amount of cell stress found in retinal pigmented epithelial (RPE) cells and in RGC [6]. Recently, we found that blue light and oxidative stress is also generated directly within the outer segments of photoreceptors - not only in the mitochondria of the inner segment [5]. Interestingly, we could also show (and corroborate findings of the group of Wong Riley and others) that red or infrared light (by water filtered infrared A – wIRA) has a beneficial effect on cell cultures and even on retinal whole mounts [14].
At the moment, we (Dr. Röhlecke, S. Bola, N. Heinig) try to probe if this red light is also protective or beneficial for regeneration in the photoreceptors especially their outer segments. The effect on red light on the mitochondrial respiratory chain will be further studied.
Very promising are the projects "Radical production of photoreceptor outer segments" and "Ectopic respiratory chain within the photoreceptor outer segments and within axonal sheets by oligodendroglia". Here, we could show recently that reactive oxygen species (ROS) are produced after blue light irradiation directly by the outer segments of the photoreceptors and not only by the mitochondria of the inner segment [16].
This ROS production can be attributet to the direct activity of actropic respiratory enzymes incorporated within the membranes of the photoreceptor outer segments. The significance of this funding as well as the existance of ectropic respiratory chain enzymes within the myelin sheets of oligodendrocytes is the topic of present studies in cooperation with the groups of J. Panfoli (University of Genova, Italy).
Another new area in retina research is regeneration or at least neuroprotection with the help of mesenchymal stem cells (MSC) Patent: EU 50 2005 008 759.3-08 (Zander / Engelmann).
Here, we (group Prof. Engelmann, D. Wittig, A. Höfer and the group of Prof. Zander in Hamburg) have the opportunity in a founder program of the Germany ministry of commerce (BMWi) to develop therapies for retinal degeneration with the aid of locally administered MSC.
In cooperation with the group Prof. Engelmann (see Klinikum Chemnitz and CRTD) we are also working on cornea and releated topics in Tissue Engineering [10].
Funding: Volkswagen Stiftung “Developing and applying nanoscopic collagen templates for biotechnology, molecular cell biology and medicine”, and industry. Saxonian state funding.
In the retina research we cooperate with the groups of Prof. M. Brand [11], Dr. M. Ader and Dr. M. Karl (CRTD), with the groups of Dr. D. Corbeil, (Med. Faculty TUD), Prof. E. Knust and Prof. W. Huttner (MPI-CBG).
- Pan-Montojo F, Anichtchik O, Dening Y, Knels L, Pursche S, Jung R, Jackson S, Gille G, Spillantini MG, Reichmann H, Funk RHProgression of Parkinson's disease pathology is reproduced by intragastric administration of rotenone in mice.
PLoS One. 2010 Jan 19;5(1):e8762; PubMed PMID: 20098733 - Knels L, Worm M, Wendel M, Roehlecke C, Kniep E, Funk RH
Effects of advanced glycation end products-inductor glyoxal and hydrogen peroxide as oxidative stress factors on rat retinal organ cultures and neuroprotection by UK-14,304
J Neurochem. 2008 Aug;106(4):1876-87. Epub 2008 Jul 4; PubMed PMID: 18624919 - Roehlecke C, Schaller A, Knels L, Funk RH
The influence of sublethal blue light exposure on human RPE cells.
Mol Vis. 2009 Sep 21;15:1929-38; PubMed PMID: 19784391; PubMed Central PMCID: PMC2751800 - Kniep EM, Roehlecke C, Ozkucur N, Steinberg A, Reber F, Knels L, Funk RH
Inhibition of apoptosis and reduction of intracellular pH decrease in retinal neural cell cultures by a blocker of carbonic anhydrase.
Invest Ophthalmol Vis Sci. 2006 Mar;47(3):1185-92; PubMed PMID: 16505057 - Roehlecke C, Schumann U, Ader M, Brunssen C, Bramke S, Morawietz H, Funk RH
Stress reaction in outer segments of photoreceptors after blue light irradiation.
PLoS One. 2013 Sep 11;8(9):e71570. doi: 10.1371/journal.pone.0071570. eCollection 2013 - Reber F, Reber U, Funk RH
Intracellular changes in astrocytes and NG 108-15 neuroblastoma X glioma cells induced by advanced glycation end products.
J Neural Transm. 2003 Oct;110(10):1103-18; PubMed PMID: 14523623 - Knels L, Valtink M, Roehlecke C, Lupp A, de la Vega J, Mehner M, Funk RH
Blue light stress in retinal neuronal (R28) cells is dependent on wavelength range and irradiance.
Eur J Neurosci. 2011 Aug;34(4):548-58. doi: 10.1111/j.1460-9568.2011.07790.x. PubMed PMID: 21781192 - Roehlecke C, Schumann U, Ader M, Knels L, Funk RH
Influence of blue light on photoreceptors in a live retinal explant system.
Mol Vis. 2011 Apr 8;17:876-84. PubMed PMID: 21527999; PubMed Central PMCID: PMC3081800 - Ulbrich S, Friedrichs J, Valtink M, Murovski S, Franz CM, Müller DJ, Funk RH, Engelmann K
Retinal pigment epithelium cell alignment on nanostructured collagen matrices.
Cells Tissues Organs. 2011;194(6):443-56. Epub 2011 Mar 11. PubMed PMID: 21411961 - Gruschwitz R, Friedrichs J, Valtink M, Franz CM, Müller DJ, Funk RH, Engelmann K.
Alignment and cell-matrix interactions of human corneal endothelial cells on nanostructured collagen type I matrices.
Invest Ophthalmol Vis Sci. 2010 Dec;51(12):6303-10. Epub 2010 Jul 14. PubMed PMID: 20631237 - Hochmann S, Kaslin J, Hans S, Weber A, Machate A, Geffarth M, Funk RH, Brand M.
Fgf Signaling is Required for Photoreceptor Maintenance in the Adult Zebrafish Retina.
PLoS One. 2012;7(1):e30365. Epub 2012 Jan 26. PubMed PMID: 22291943; PubMed Central PMCID: PMC3266925 - Krafft C, Knetschke T, Funk RH, Salzer R
Studies on stress-induced changes at the subcellular level by Raman microspectroscopic mapping.
Anal Chem. 2006 Jul 1;78(13):4424-9 - Schweizer J, Hollmach J, Steiner G, Knels L, Funk RH, Koch E
Hyperspectral imaging - A new modality for eye diagnostics.
Biomed Tech (Berl). 2012 Sep 6. pii: /j/bmte.2012.57.issue-s1-P/bmt-2012-4375/bmt-2012-4375.xml.
doi:10.1515/bmt-2012-4375. [Epub ahead of print] - Knels L, Valtink M, De la Vega Marin J, Steiner G, Roehlecke C, Krueger A, Funk RH
Effects of temperature and water-filtered infrared-A alone or in combination on healthy and glyoxal-stressed fibroblast cultures.
Oxid Med Cell Longev. 2012;2012:274953. doi: 10.1155/2012/274953. Epub 2012 Oct 17 - Pan-Montojo F, Schwarz M, Winkler C, Arnhold M, O'Sullivan GA, Pal A, Said J, Marsico G, Verbavatz JM, Rodrigo-Angulo M, Gille G, Funk RH, Reichmann H
Environmental toxins trigger PD-like progression via increased alpha-synuclein release from enteric neurons in mice.
Sci Rep. 2012;2:898. doi: 10.1038/srep00898. Epub 2012 Nov 30 - Roehlecke C, Schumann U, Ader M, Brunssen C, Bramke S, Morawietz H, Funk RH
Stress reaction in outer segments of photoreceptors after blue light irradiation.
PLoS One. 2013 Sep 11;8(9):e71570. doi: 10.1371/journal.pone.0071570. eCollection 2013. PubMed PMID: 24039718; PubMed Central PMCID: PMC3770596 - Wittig D, Jászai J, Corbeil D, Funk RH
Immunohistochemical localization and characterization of putative mesenchymal stem cell markers in the retinal capillary network of rodents.
Cells Tissues Organs. 2013;197(5):344-59. doi: 10.1159/000346661. Epub 2013 Apr 3. PubMed PMID: 23571553 - Pan-Montojo F, Funk RH
Implications of Parkinson's disease pathophysiology for the development of cell replacement strategies and drug discovery in neurodegenerative diseases.
CNS Neurol Disord Drug Targets. 2012 Nov 1;11(7):907-20. Review. PubMed PMID: 23131153