19 research outputs found
Modifier Genes as Therapeutics: The Nuclear Hormone Receptor Rev Erb Alpha (Nr1d1) Rescues Nr2e3 Associated Retinal Disease
Nuclear hormone receptors play a major role in many important biological processes. Most nuclear hormone receptors are
ubiquitously expressed and regulate processes such as metabolism, circadian function, and development. They function in
these processes to maintain homeostasis through modulation of transcriptional gene networks. In this study we evaluate
the effectiveness of a nuclear hormone receptor gene to modulate retinal degeneration and restore the integrity of the
retina. Currently, there are no effective treatment options for retinal degenerative diseases leading to progressive and
irreversible blindness. In this study we demonstrate that the nuclear hormone receptor gene Nr1d1 (Rev-Erba) rescues Nr2e3-
associated retinal degeneration in the rd7 mouse, which lacks a functional Nr2e3 gene. Mutations in human NR2E3 are
associated with several retinal degenerations including enhanced S cone syndrome and retinitis pigmentosa. The rd7
mouse, lacking Nr2e3, exhibits an increase in S cones and slow, progressive retinal degeneration. A traditional genetic
mapping approach previously identified candidate modifier loci. Here, we demonstrate that in vivo delivery of the candidate
modifier gene, Nr1d1 rescues Nr2e3 associated retinal degeneration. We observed clinical, histological, functional, and
molecular restoration of the rd7 retina. Furthermore, we demonstrate that the mechanism of rescue at the molecular and
functional level is through the re-regulation of key genes within the Nr2e3-directed transcriptional network. Together, these
findings reveal the potency of nuclear receptors as modulators of disease and specifically of NR1D1 as a novel therapeutic
for retinal degenerations
ALPK1 missense pathogenic variant in five families leads to ROSAH syndrome, an ocular multisystem autosomal dominant disorder
Purpose: To identify the molecular cause in five unrelated families
with a distinct autosomal dominant ocular systemic disorder we
called ROSAH syndrome due to clinical features of retinal dystrophy,
optic nerve edema, splenomegaly, anhidrosis, and migraine headache.
Methods: Independent discovery exome and genome sequencing
in families 1, 2, and 3, and confirmation in families 4 and 5.
Expression of wild-type messenger RNA and protein in human and
mouse tissues and cell lines. Ciliary assays in fibroblasts from
affected and unaffected family members.
Results: We found the heterozygous missense variant in the ɑkinase gene, ALPK1, (c.710C>T, [p.Thr237Met]), segregated with
disease in all five families. All patients shared the ROSAH
phenotype with additional low-grade ocular inflammation, pancytopenia, recurrent infections, and mild renal impairment in some.
ALPK1 was notably expressed in retina, retinal pigment epithelium,
and optic nerve, with immunofluorescence indicating localization
to the basal body of the connecting cilium of the photoreceptors,
and presence in the sweat glands. Immunocytofluorescence
revealed expression at the centrioles and spindle poles during
metaphase, and at the base of the primary cilium. Affected family
member fibroblasts demonstrated defective ciliogenesis.
Conclusion: Heterozygosity for ALPK1, p.Thr237Met leads to
ROSAH syndrome, an autosomal dominant ocular systemic
disorder
Genome-wide association meta-analysis of corneal curvature identifies novel loci and shared genetic influences across axial length and refractive error.
Corneal curvature, a highly heritable trait, is a key clinical endophenotype for myopia - a major cause of visual impairment and blindness in the world. Here we present a trans-ethnic meta-analysis of corneal curvature GWAS in 44,042 individuals of Caucasian and Asian with replication in 88,218 UK Biobank data. We identified 47 loci (of which 26 are novel), with population-specific signals as well as shared signals across ethnicities. Some identified variants showed precise scaling in corneal curvature and eye elongation (i.e. axial length) to maintain eyes in emmetropia (i.e. HDAC11/FBLN2 rs2630445, RBP3 rs11204213); others exhibited association with myopia with little pleiotropic effects on eye elongation. Implicated genes are involved in extracellular matrix organization, developmental process for body and eye, connective tissue cartilage and glycosylation protein activities. Our study provides insights into population-specific novel genes for corneal curvature, and their pleiotropic effect in regulating eye size or conferring susceptibility to myopia
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Metagenomic analysis of permafrost microbial community response to thaw
We employed deep metagenomic sequencing to determine the impact of thaw on microbial phylogenetic and functional genes and related this data to measurements of methane emissions. Metagenomics, the direct sequencing of DNA from the environment, allows for the examination of whole biochemical pathways and associated processes, as opposed to individual pieces of the metabolic puzzle. Our metagenome analyses revealed that during transition from a frozen to a thawed state there were rapid shifts in many microbial, phylogenetic and functional gene abundances and pathways. After one week of incubation at 5°C, permafrost metagenomes converged to be more similar to each other than while they were frozen. We found that multiple genes involved in cycling of C and nitrogen shifted rapidly during thaw. We also constructed the first draft genome from a complex soil metagenome, which corresponded to a novel methanogen. Methane previously accumulated in permafrost was released during thaw and subsequently consumed by methanotrophic bacteria. Together these data point towards the importance of rapid cycling of methane and nitrogen in thawing permafrost
Complement deficiency promotes cutaneous wound healing in mice
Wound healing is a complex homeostatic response to injury that engages numerous cellular activities, processes, and cell-to-cell interactions. The complement system, an intricate network of proteins with important roles in immune surveillance and homeostasis, has been implicated in many physiological processes; however, its role in wound healing remains largely unexplored. In this study, we employ a murine model of excisional cutaneous wound healing and show that C3-/- mice exhibit accelerated early stages of wound healing. Reconstitution of C3-/- mice with serum from C3+/+ mice or purified human C3 abrogated the accelerated wound-healing phenotype. Wound histology of C3-/- mice revealed a reduction in inflammatory infiltrate compared with C3+/+ mice. C3 deficiency also resulted in increased accumulation of mast cells and advanced angiogenesis. We further show that mice deficient in the downstream complement effector C5 exhibit a similar wound-healing phenotype, which is recapitulated in C5aR1-/- mice, but not C3aR-/- or C5aR2-/- mice. Taken together, these data suggest that C5a signaling through C5aR may in part play a pivotal role in recruitment and activation of inflammatory cells to the wound environment, which in turn could delay the early stages of cutaneous wound healing. These findings also suggest a previously underappreciated role for complement in wound healing, and may have therapeutic implications for conditions of delayed wound healing. Copyright © 2015 by The American Association of Immunologists, Inc
Genetic variants in complement pathway and ARMS2/HTRA1 genes and risk of age-related macular degeneration in a homogeneous population from central Greece
[No abstract available