Gene expression changes within Müller glial cells in retinitis pigmentosa.
OBJECTIVE
Retinitis pigmentosa (RP) is a progressive retinal degeneration in which the retina loses nearly all of its photoreceptor cells and undergoes major structural changes. Little is known regarding the role the resident glia, the Müller glia, play in the progression of the disease. In this article, we define gene expression changes in Müller glial cells (MGCs) from two different mouse models of RP, the retinal degeneration 1 (rd1) and rhodopsin knockout (Rhod-ko) models. The RNA repertoire of single MGCs was comprehensively profiled, and a comparison was made between MGCs from wild-type (WT) and mutant retinas. Two time points were chosen for analysis, one at the peak of rod photoreceptor death and one during the period of cone photoreceptor death.


METHODS
Retinas were dissociated, and single MGCs were chosen under a dissecting microscope using a micropipette. Single cell cDNAs were generated and genome-wide profiles were obtained by hybridization to Affymetrix arrays. A comparison was made among all samples to discover the changes in gene expression during the periods of rod and cone photoreceptor death.


RESULTS
MGCs respond to retinal degeneration by undergoing gliosis, a process marked by the upregulation of glial fibrillary acidic protein (Gfap). Many additional transcripts were found to change. These can be placed into functional clusters, such as retinal remodeling, stress response, and immune-related response.


CONCLUSIONS
A high degree of heterogeneity among the individual cells was observed, possibly due to their different spatial proximities to dying cells and/or inherent heterogeneity among MGCs.
Department of Genetics, Harvard Medical School, and Howard Hughes Medical Institute, Boston, MA 02115, USA.
Karin
K
Roesch
Michael B
MB
Stadler
Constance L
CL
Cepko
D000818:Animals; D016923:Cell Death / Q000235:genetics; D015870:Gene Expression; D020869:Gene Expression Profiling; D055786:Gene Knockout Techniques; D005904:Glial Fibrillary Acidic Protein; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000096:biosynthesis; D012160:Retina / Q000378:metabolism* / Q000473:pathology; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism / Q000473:pathology; D012162:Retinal Degeneration / Q000235:genetics* / Q000378:metabolism; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism / Q000473:pathology; D012174:Retinitis Pigmentosa / Q000235:genetics* / Q000378:metabolism; D012243:Rhodopsin / Q000172:deficiency / Q000235:genetics; D059010:Single-Cell Analysis; D015854:Up-Regulation
D005904:Glial Fibrillary Acidic Protein; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C528900:glial fibrillary astrocytic protein, mouse; D012243:Rhodopsin