Mice with an induced mutation in collagen 8A2 develop larger eyes and are resistant to retinal ganglion cell damage in an experimental glaucoma model

PURPOSE: To study susceptibility to glaucoma injury as it may be affected by mutations in ocular connective tissue components. METHODS: Mice homozygous for an N-ethyl-N-nitrosourea induced G257D exchange (Gly to Asp) missense mutation (Aca23) in their collagen 8A2 gene were studied to measure intraocular pressure (IOP), axial length and width, number of retinal ganglion cells (RGC), and inflation responses. Three month old homozygous Aca23 mutant and wild type (WT) mice had 6 weeks exposure to elevated IOP induced by polystyrene microbead injection. Additional Aca23 and matched controls were studied at ages of 10 and 18 months. RESULTS: Aca23 mice had no significant difference from WT in IOP level, and in both strains IOP rose with age. In multivariable models, axial length and width were significantly larger in Aca23 than WT, became larger with age, and were larger after exposure to glaucoma (n=227 mice). From inflation test data, the estimates of scleral stress resultants in Aca23 mice were similar to age-matched and younger WT C57BL/6 (B6) mice, while the strain estimates for Aca23 were significantly less than those for either WT group in the mid-sclera and in some of the more anterior scleral measures (p<0.001; n=29, 22, 20 eyes in Aca23, older WT, younger WT, respectively). With chronic IOP elevation, Aca23 eyes increased 9% in length and 7% in width, compared to untreated fellow eyes (p<0.05, <0.01). With similar elevated IOP exposure, WT eyes enlarged proportionately twice as much as Aca23, increasing in length by 18% and in nasal-temporal width by 13% (both p<0.001, Mann-Whitney test). In 4 month old control optic nerves, mean RGC axon number was not different in Aca23 and WT (46,905±7,592, 43,628±11,162, respectively; p=0.43, Mann-Whitney test, n=37 and 29). With chronic glaucoma, Aca23 mice had a mean axon loss of only 0.57±17%, while WT mice lost 21±31% (median loss: 1% versus 10%, n=37, 29, respectively; p=0.001; multivariable model adjusting for positive integral IOP exposure). CONCLUSIONS: The Aca23 mutation in collagen 8α2 is the first gene defect found to alter susceptibility to experimental glaucoma, reducing RGC loss possibly due to differences in mechanical behavior of the sclera. Detailed study of the specific changes in scleral connective tissue composition and responses to chronic IOP elevation in this strain could produce new therapeutic targets for RGC neuroprotection

Mobile Air Quality Studies (MAQS) - an international project

Due to an increasing awareness of the potential hazardousness of air pollutants, new laws, rules and guidelines have recently been implemented globally. In this respect, numerous studies have addressed traffic-related exposure to particulate matter using stationary technology so far. By contrast, only few studies used the advanced technology of mobile exposure analysis. The Mobile Air Quality Study (MAQS) addresses the issue of air pollutant exposure by combining advanced high-granularity spatial-temporal analysis with vehicle-mounted, person-mounted and roadside sensors. The MAQS-platform will be used by international collaborators in order 1) to assess air pollutant exposure in relation to road structure, 2) to assess air pollutant exposure in relation to traffic density, 3) to assess air pollutant exposure in relation to weather conditions, 4) to compare exposure within vehicles between front and back seat (children) positions, and 5) to evaluate "traffic zone"- exposure in relation to non-"traffic zone"-exposure. Primarily, the MAQS-platform will focus on particulate matter. With the establishment of advanced mobile analysis tools, it is planed to extend the analysis to other pollutants including including NO2, SO2, nanoparticles, and ozone

Pleiotropic effects in Eya3 knockout mice

<p>Abstract</p> <p>Background</p> <p>In <it>Drosophila</it>, mutations in the gene <it>eyes absent </it>(<it>eya</it>) lead to severe defects in eye development. The functions of its mammalian orthologs <it>Eya1-4 </it>are only partially understood and no mouse model exists for <it>Eya3</it>. Therefore, we characterized the phenotype of a new <it>Eya3 </it>knockout mouse mutant.</p> <p>Results</p> <p>Expression analysis of <it>Eya3 </it>by <it>in-situ </it>hybridizations and β-Gal-staining of <it>Eya3 </it>mutant mice revealed abundant expression of the gene throughout development, e.g. in brain, eyes, heart, somites and limbs suggesting pleiotropic effects of the mutated gene. A similar complex expression pattern was observed also in zebrafish embryos.</p> <p>The phenotype of young adult <it>Eya3 </it>mouse mutants was systematically analyzed within the German Mouse Clinic. There was no obvious defect in the eyes, ears and kidneys of <it>Eya3 </it>mutant mice. Homozygous mutants displayed decreased bone mineral content and shorter body length. In the lung, the tidal volume at rest was decreased, and electrocardiography showed increased JT- and PQ intervals as well as decreased QRS amplitude. Behavioral analysis of the mutants demonstrated a mild increase in exploratory behavior, but decreased locomotor activity and reduced muscle strength. Analysis of differential gene expression revealed 110 regulated genes in heart and brain. Using real-time PCR, we confirmed <it>Nup155 </it>being down regulated in both organs.</p> <p>Conclusion</p> <p>The loss of <it>Eya3 </it>in the mouse has no apparent effect on eye development. The wide-spread expression of <it>Eya3 </it>in mouse and zebrafish embryos is in contrast to the restricted expression pattern in <it>Xenopus </it>embryos. The loss of <it>Eya3 </it>in mice leads to a broad spectrum of minor physiological changes. Among them, the mutant mice move less than the wild-type mice and, together with the effects on respiratory, muscle and heart function, the mutation might lead to more severe effects when the mice become older. Therefore, future investigations of <it>Eya3 </it>function should focus on aging mice.</p

Large-Scale Phenotyping of an Accurate Genetic Mouse Model of JNCL Identifies Novel Early Pathology Outside the Central Nervous System

Cln3Δex7/8 mice harbor the most common genetic defect causing juvenile neuronal ceroid lipofuscinosis (JNCL), an autosomal recessive disease involving seizures, visual, motor and cognitive decline, and premature death. Here, to more thoroughly investigate the manifestations of the common JNCL mutation, we performed a broad phenotyping study of Cln3Δex7/8 mice. Homozygous Cln3Δex7/8 mice, congenic on a C57BL/6N background, displayed subtle deficits in sensory and motor tasks at 10–14 weeks of age. Homozygous Cln3Δex7/8 mice also displayed electroretinographic changes reflecting cone function deficits past 5 months of age and a progressive decline of retinal post-receptoral function. Metabolic analysis revealed increases in rectal body temperature and minimum oxygen consumption in 12–13 week old homozygous Cln3Δex7/8mice, which were also seen to a lesser extent in heterozygous Cln3Δex7/8 mice. Heart weight was slightly increased at 20 weeks of age, but no significant differences were observed in cardiac function in young adults. In a comprehensive blood analysis at 15–16 weeks of age, serum ferritin concentrations, mean corpuscular volume of red blood cells (MCV), and reticulocyte counts were reproducibly increased in homozygous Cln3Δex7/8 mice, and male homozygotes had a relative T-cell deficiency, suggesting alterations in hematopoiesis. Finally, consistent with findings in JNCL patients, vacuolated peripheral blood lymphocytes were observed in homozygous Cln3Δex7/8 neonates, and to a greater extent in older animals. Early onset, severe vacuolation in clear cells of the epididymis of male homozygous Cln3Δex7/8 mice was also observed. These data highlight additional organ systems in which to study CLN3 function, and early phenotypes have been established in homozygous Cln3Δex7/8 mice that merit further study for JNCL biomarker development

The border sequence of the balhimycin biosynthesis gene cluster from Amycolatopsis balhimycina contains bbr, encoding a StrR-like pathway-specific regulator

Balhimycin, produced by the actinomycete Amycolatopsis balhimycina DSM5908, is a glycopeptide antibiotic highly similar to vancomycin, the antibiotic of 'last resort' used for the treatment of resistant Gram-positive pathogenic bacteria. Partial sequence of the balhimycin biosynthesis gene cluster was previously reported. In this work, cosmids which overlap the region of the characterized gene cluster were isolated and sequenced. At the 'left' end of the cluster, genes were identified which are involved in balhimycin biosynthesis, transport, resistance and regulation. The 'right' end border is defined by a putative 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (dahp) gene. The proximate gene is similar to a type I polyketide synthase gene of the rifamycin producer Amycolatopsis mediterranei indicating that another biosynthesis gene cluster might be located directly next to the balhimycin gene cluster. The newly identified StrR-like pathway-specific regulator, Bbr, was characterized to be a DNA-binding protein and may have a role in balhimycin biosynthesis. Purified N-terminally His-tagged Bbr shows specific DNA-binding to five promoter regions within the gene cluster. By in silico analysis and by comparison of the DNA sequences binding Bbr, conserved inverted repeat sequences for the Bbr-binding site are proposed. The putative Bbr consensus sequence differs from that published for StrR. Copyright (c) 2007 S. Karger AG, Basel

Biosynthesis of Chloro-β-Hydroxytyrosine, a Nonproteinogenic Amino Acid of the Peptidic Backbone of Glycopeptide Antibiotics

The role of the putative P450 monooxygenase OxyD and the chlorination time point in the biosynthesis of the glycopeptide antibiotic balhimycin produced by Amycolatopsis balhimycina were analyzed. The oxyD gene is located directly downstream of the bhp (perhydrolase) and bpsD (nonribosomal peptide synthetase D) genes, which are involved in the synthesis of the balhimycin building block β-hydroxytyrosine (β-HT). Reverse transcriptase experiments revealed that bhp, bpsD, and oxyD form an operon. oxyD was inactivated by an in-frame deletion, and the resulting mutant was unable to produce an active compound. Balhimycin production could be restored (i) by complementation with an oxyD gene, (ii) in cross-feeding studies using A. balhimycina JR1 (a null mutant with a block in the biosynthesis pathway of the building blocks hydroxy- and dihydroxyphenylglycine) as an excretor of the missing precursor, and (iii) by supplementation of β-HT in the growth medium. These data demonstrated an essential role of OxyD in the formation pathway of this amino acid. Liquid chromatography-electrospray ionization-mass spectrometry analysis indicated the biosynthesis of completely chlorinated balhimycin by the oxyD mutant when culture filtrates were supplemented with nonchlorinated β-HT. In contrast, supplementation with 3-chloro-β-HT did not restore balhimycin production. These results indicated that the chlorination time point was later than the stage of free β-HT, most likely during heptapeptide synthesis

KBG syndrome: videoconferencing and use of artificial intelligence driven facial phenotyping in 25 new patients

[EN] Genetic variants in Ankyrin Repeat Domain 11 (ANKRD11) and deletions in 16q24.3 are known to cause KBG syndrome, a rare syndrome associated with craniofacial, intellectual, and neurobehavioral anomalies. We report 25 unpublished individuals from 22 families with molecularly confirmed diagnoses. Twelve individuals have de novo variants, three have inherited variants, and one is inherited from a parent with low-level mosaicism. The mode of inheritance was unknown for nine individuals. Twenty are truncating variants, and the remaining five are missense (three of which are found in one family). We present a protocol emphasizing the use of videoconference and artificial intelligence (AI) in collecting and analyzing data for this rare syndrome. A single clinician interviewed 25 individuals throughout eight countries. Participants' medical records were reviewed, and data was uploaded to the Human Disease Gene website using Human Phenotype Ontology (HPO) terms. Photos of the participants were analyzed by the GestaltMatcher and DeepGestalt, Face2Gene platform (FDNA Inc, USA) algorithms. Within our cohort, common traits included short stature, macrodontia, anteverted nares, wide nasal bridge, wide nasal base, thick eyebrows, synophrys and hypertelorism. Behavioral issues and global developmental delays were widely present. Neurologic abnormalities including seizures and/or EEG abnormalities were common (44%), suggesting that early detection and seizure prophylaxis could be an important point of intervention. Almost a quarter (24%) were diagnosed with attention deficit hyperactivity disorder and 28% were diagnosed with autism spectrum disorder. Based on the data, we provide a set of recommendations regarding diagnostic and treatment approaches for KBG syndrome.This research was supported in part by funds provided to GJL from the New York State Office for People with Developmental Disabilities and NIH NIGMS R35-GM133408, and also a University of Alberta Hospital Foundation Gilbert K. Winter grant awarded to AV and Women and Children Hospital Research Institute scholarship awarded to YK. KW is supported by NIH/NLM grant LM012895.Guo, L.; Park, J.; Yi, E.; Marchi, E.; Hsieh, T.; Kibalnyk, Y.; Moreno-Sáez, Y.... (2022). KBG syndrome: videoconferencing and use of artificial intelligence driven facial phenotyping in 25 new patients. European Journal of Human Genetics. 30(11):1244-1254. https://doi.org/10.1038/s41431-022-01171-112441254301