GpnmbR150X allele must be present in bone marrow derived cells to mediate DBA/2J glaucoma

<p>Abstract</p> <p>Background</p> <p>The <it>Gpnmb </it>gene encodes a transmembrane protein whose function(s) remain largely unknown. Here, we assess if a mutant allele of <it>Gpnmb </it>confers susceptibility to glaucoma by altering immune functions. DBA/2J mice have a mutant <it>Gpnmb </it>gene and they develop a form of glaucoma preceded by a pigment dispersing iris disease and abnormalities of the immunosuppressive ocular microenvironment.</p> <p>Results</p> <p>We find that the <it>Gpnmb </it>genotype of bone-marrow derived cell lineages significantly influences the iris disease and the elevation of intraocular pressure. GPNMB localizes to multiple cell types, including pigment producing cells, bone marrow derived F4/80 positive antigen-presenting cells (APCs) of the iris and dendritic cells. We show that APCs of DBA/2J mice fail to induce antigen induced immune deviation (a form of tolerance) when treated with TGFβ2. This demonstrates that some of the immune abnormalities previously identified in DBA/2J mice result from intrinsic defects in APCs. However, the tested APC defects are not dependent on a mutant <it>Gpnmb </it>gene. Finally, we show that the <it>Gpnmb </it>mediated iris disease does not require elevated IL18 or mature B or T lymphocytes.</p> <p>Conclusion</p> <p>These results establish a role for <it>Gpnmb </it>in bone marrow derived lineages. They suggest that affects of <it>Gpnmb </it>on innate immunity influence susceptibility to glaucoma in DBA/2J mice.</p

Motility Of A Biflagellate Sperm: Waveform Analysis And Cyclic Nucleotide Activation

The sperm of the freshwater clam Corbicula fluminea are unusual in that they have two flagella, both of which are capable of beating. When Corbicula sperm are removed from the gonad and placed into freshwater, most remain immotile. Video microscopy was used to assess signaling molecules capable of activating Corbicula sperm motility. Experiments using the cAMP analogs dbcAMP or 8-Br-cAMP show that elevating cAMP activates flagellar motility. Treatments with 8-Br-cGMP activated motility in similar numbers of sperm. Treatments with the selective cAMP-dependent protein kinase (PKA) inhibitor H-89 block activation by 8-Br-cAMP but not by 8-Br-cGMP. Similar treatments with the cGMP-dependent protein kinase (PKG) inhibitor Rp-8-pCPT-cGMPS block activation by 8-Br-cGMP but not by 8-Br-cAMP. These results suggest that cAMP and cGMP each work through their specific kinase to activate flagellar motility. Analysis of spontaneously activated freely swimming sperm shows that the two flagella beat with different parameters. The A flagellum beats with a shorter wavelength and a higher frequency than the B flagellum. The observed differences in flagellar waveform indicate that the flagella are differentially controlled. © 2004 Wiley-Liss, Inc

Elevated Oxidative Membrane Damage Associated with Genetic Modifiers of Lyst-Mutant Phenotypes

LYST is a large cytosolic protein that influences the biogenesis of lysosome-related organelles, and mutation of the encoding gene, LYST, can cause Chediak-Higashi syndrome. Recently, Lyst-mutant mice were recognized to also exhibit an iris disease resembling exfoliation syndrome, a common cause of glaucoma in humans. Here, Lyst-mutant iris phenotypes were used in a search for genes that influence Lyst pathways. In a candidate gene–driven approach, albino Lyst-mutant mice homozygous for a mutation in Tyr, whose product is key to melanin synthesis within melanosomes, exhibited complete rescue of Lyst-mutant iris phenotypes. In a genetic background–driven approach using a DBA/2J strain of congenic mice, an interval containing Tyrp1 enhanced Lyst-dependent iris phenotypes. Thus, both experimental approaches implicated the melanosome, an organelle that is a potential source of oxidative stress, as contributing to the disease phenotype. Confirming an association with oxidative damage, Lyst mutation resulted in genetic context–sensitive changes in iris lipid hydroperoxide levels, being lowest in albino and highest in DBA/2J mice. Surprisingly, the DBA/2J genetic background also exposed a late-onset neurodegenerative phenotype involving cerebellar Purkinje-cell degeneration. These results identify an association between oxidative damage to lipid membranes and the severity of Lyst-mutant phenotypes, revealing a ne

Microarray Analysis of Iris Gene Expression in Mice with Mutations Influencing Pigmentation

This was a study of global gene expression in the iris in wild-type C57BL/6J mice and mouse models of three diseases affecting the iris: albinism, pigment dispersion syndrome, and exfoliation syndrome. The results identify several candidate genes potentially contributing to human disease and have several biologically relevant implications, particularly with respect to secondary forms of glaucoma

Lyst Mutation in Mice Recapitulates Iris Defects of Human Exfoliation Syndrome

PURPOSE. Human eyes with exfoliation syndrome (XFS) exhibit a distinctive pattern of iris transillumination defects that are recapitulated in Lyst mutant mice carrying the beige allele. The purpose of this study was to determine the anatomic basis for Lyst-mediated transillumination defects, test whether Lyst mutant mice develop other features of XFS, and describe the molecular basis of the beige mutation. METHODS. Lyst mutant mice and strain-matched controls were compared by clinical, histologic, immunohistochemical, and molecular genetic analyses. RESULTS. Slit-lamp examination showed that Lyst mutant mice uniformly exhibit XFS-like transillumination defects. Histologic analysis showed that these defects correlate with a sawtooth morphology of the iris pigment epithelium. Lyst mutant mice also produce an exfoliative-like material and exhibit pronounced pigment dispersion. Despite these insults, Lyst mutation does not cause increased intraocular pressure or optic nerve damage in the C57BL/6J genetic background. Sequence analysis identified that the beige mutation is predicted to delete a single isoleucine from the WD40 domain of the LYST protein, suggesting that this mutation is likely to disrupt a proteinprotein interaction. CONCLUSIONS. Lyst mutant eyes exhibit multiple features of XFS. Recent human genetic association studies have identified changes occurring in the LOXL1 gene as an important risk factor for XFS but also indicated that other factors contributing to risk likely exist. These results demonstrated that mutation of the Lyst gene can produce ocular features of human XFS and suggested that LYST or LYST-interacting genes may contribute to XFS. (Invest Ophthalmol Vis Sci. 2009;50:1205-1214) DOI: 10.1167/iovs.08-2791 E xfoliation syndrome (XFS) is a common age-related disorder primarily recognized by the pathologic accumulations of a fibrillar exfoliative material in the anterior chamber of the eye but also associated with several other ocular and systemic abnormalities. 7 In parallel to the clinical significance of exfoliative material in the diagnosis of XFS, much of the experimental work on XFS syndrome has focused on studies of exfoliative material. Such studies have shown that exfoliative material consists of an irregular conglomeration of randomly cross-banded fibrils approximately 30 nm in diameter surrounded by an amorphous matrix of glycoconjugates. 8 Exfoliative material also contains epitopes for a variety of proteins related to elastic microfibers, including fibrillin-1, 9 elastin, 10 latent TGF-␤ proteins, 11 lysyl oxidase, 4 and others. 3,4 These results and other experimental work on XFS have led to a hypothesis that XFS is a disease of elastosis. According to this theory, insults such as increased oxidative stress and elevated levels of TGF-␤1 likely trigger increased production of elastic microfibrils that are subsequently prone to aggregate and accumulate. A breakthrough in understanding XFS has been precipitated by genomewide association studies that have begun to unravel the genetic factors underlying XFS. XFS has long been appreciated to have strong hereditary contributions. 14 However, the influence of LOXL1 in XFS may not be as straightforward as is seemingly indicated by these impressive statistics. A multifactorial risk for XFS is suggested by the extremely high occurrence of high-risk LOXL1 alleles among the general population. Within the original Scandinavian populations studied, the high-risk haplotype of LOXL1 alleles was also detected at a frequency of approximately 50% in the general population, with approximately 25% of the general population homozygous for the haplotype. 14 Follow-up studies have also confirmed similar high-carrier frequencies. Here, we identify the Lyst gene as an additional gene potentially important to XFS. B6-Lyst bg-J mice homozygous for the beige-J (bg-J) allele recapitulate multiple ocular features of human XFS. Our initial consideration of B6-Lyst bg-J mice as a possible model of XFS was based on a resemblance of iris transillumination defects between these mice and human patients with XFS. In testing the anatomic basis for the Lyst

Allele must be present in bone marrow derived cells to mediate DBA/2J glaucoma-5

E determined by ELISA. IL18 levels are expressed as mean +/- SEM from 5 aqueous humor samples in each group. Quantitative RT-PCR analysis comparing expression levels of IL18 transcript in ciliary body enriched dissections of 10.5 mo old D2, D2.and B6.mice. The threshold cycle was calculated with normalization to and values are expressed as mean +/- SEM, with 3–5 samples in each group.<p><b>Copyright information:</b></p><p>Taken from "allele must be present in bone marrow derived cells to mediate DBA/2J glaucoma"</p><p>http://www.biomedcentral.com/1471-2156/9/30</p><p>BMC Genetics 2008;9():30-30.</p><p>Published online 10 Apr 2008</p><p>PMCID:PMC2373794.</p><p></p