AOX delays the onset of the lethal phenotype in a mouse model of Uqcrh (complex III) disease.

The alternative oxidase, AOX, provides a by-pass of the cytochrome segment of the mitochondrial respiratory chain when the chain is unavailable. AOX is absent from mammals, but AOX from Ciona intestinalis is benign when expressed in mice. Although non-protonmotive, so does not contribute directly to ATP production, it has been shown to modify and in some cases rescue phenotypes of respiratory-chain disease models.

Knockout mouse models as a resource for the study of rare diseases.

Rare diseases (RDs) are a challenge for medicine due to their heterogeneous clinical manifestations and low prevalence. There is a lack of specific treatments and only a few hundred of the approximately 7,000 RDs have an approved regime. Rapid technological development in genome sequencing enables the mass identification of potential candidates that in their mutated form could trigger diseases but are often not confirmed to be causal.

Deep phenotyping and lifetime trajectories reveal limited effects of longevity regulators on the aging process in C57BL/6J mice.

Current concepts regarding the biology of aging are primarily based on studies aimed at identifying factors regulating lifespan. However, lifespan as a sole proxy measure for aging can be of limited value because it may be restricted by specific pathologies. Here, we employ large-scale phenotyping to analyze hundreds of markers in aging male C57BL/6J mice.

Characterising a homozygous two-exon deletion in UQCRH: comparing human and mouse phenotypes.

Mitochondrial disorders are clinically and genetically diverse, with isolated complex III (CIII) deficiency being relatively rare. Here, we describe two affected cousins, presenting with recurrent episodes of severe lactic acidosis, hyperammonaemia, hypoglycaemia and encephalopathy. Genetic investigations in both cases identified a homozygous deletion of exons 2 and 3 of UQCRH, which encodes a structural complex III (CIII) subunit.

Mouse mutant phenotyping at scale reveals novel genes controlling bone mineral density.

The genetic landscape of diseases associated with changes in bone mineral density (BMD), such as osteoporosis, is only partially understood. Here, we explored data from 3,823 mutant mouse strains for BMD, a measure that is frequently altered in a range of bone pathologies, including osteoporosis. A total of 200 genes were found to significantly affect BMD.

Identification of genetic elements in metabolism by high-throughput mouse phenotyping.

Metabolic diseases are a worldwide problem but the underlying genetic factors and their relevance to metabolic disease remain incompletely understood. Genome-wide research is needed to characterize so-far unannotated mammalian metabolic genes. Here, we generate and analyze metabolic phenotypic data of 2016 knockout mouse strains under the aegis of the International Mouse Phenotyping Consortium (IMPC) and find 974 gene knockouts with strong metabolic phenotypes.

Understanding gene functions and disease mechanisms: Phenotyping pipelines in the German Mouse Clinic.

Since decades, model organisms have provided an important approach for understanding the mechanistic basis of human diseases. The German Mouse Clinic (GMC) was the first phenotyping facility that established a collaboration-based platform for phenotype characterization of mouse lines. In order to address individual projects by a tailor-made phenotyping strategy, the GMC advanced in developing a series of pipelines with tests for the analysis of specific disease areas.

The First Scube3 Mutant Mouse Line with Pleiotropic Phenotypic Alterations.

The vertebrate Scube (Signal peptide, CUB, and EGF-like domain-containing protein) family consists of three independent members, Scube1-3, which encode secreted cell surface-associated membrane glycoproteins. Limited information about the general function of this gene family is available, and their roles during adulthood. Here, we present the first Scube3 mutant mouse line (Scube3), which clearly shows phenotypic alterations by carrying a missense mutation in exon 8, and thus contributes to our understanding of SCUBE3 functions.

Viable Ednra mice feature human mandibulofacial dysostosis with alopecia (MFDA) syndrome due to the homologue mutation.

Animal models resembling human mutations are valuable tools to research the features of complex human craniofacial syndromes. This is the first report on a viable dominant mouse model carrying a non-synonymous sequence variation within the endothelin receptor type A gene (Ednra c.386A>T, p.

alpha-secretase mediated conversion of the amyloid precursor protein derived membrane stub C99 to C83 limits Abeta generation.

The Swedish mutation within the amyloid precursor protein (APP) causes early-onset Alzheimer's disease due to increased cleavage of APP by BACE1. While beta-secretase shedding of Swedish APP (APPswe) largely results from an activity localized in the late secretory pathway, cleavage of wild-type APP occurs mainly in endocytic compartments. However, we show that liberation of Abeta from APPswe is still dependent on functional internalization from the cell surface.

Independent generation of Abeta42 and Abeta38 peptide species by gamma-secretase.

Proteolytic processing of the amyloid precursor protein by beta- and gamma-secretase generates the amyloid-beta (Abeta) peptides, which are principal drug targets in Alzheimer disease therapeutics. gamma-Secretase has imprecise cleavage specificity and generates the most abundant Abeta40 and Abeta42 species together with longer and shorter peptides such as Abeta38. Several mechanisms could explain the production of multiple Abeta peptides by gamma-secretase, including sequential processing of longer into shorter Abeta peptides.

Nonsteroidal anti-inflammatory drugs and ectodomain shedding of the amyloid precursor protein.

Background: Epidemiological studies have suggested that long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with a reduced incidence of Alzheimer's disease (AD). Several mechanisms have been proposed to explain these findings including increased shedding of the soluble ectodomain of the amyloid precursor protein (sAPP), which functions as a neurotrophic and neuroprotective factor in vitroand in vivo.

Objective: To clarify whether NSAIDs consistently stimulate sAPP secretion.

Curcumin-derived pyrazoles and isoxazoles: Swiss army knives or blunt tools for Alzheimer's disease?

Curcumin binds to the amyloid beta peptide (Abeta) and inhibits or modulates amyloid precursor protein (APP) metabolism. Therefore, curcumin-derived isoxazoles and pyrazoles were synthesized to minimize the metal chelation properties of curcumin. The decreased rotational freedom and absence of stereoisomers was predicted to enhance affinity toward Abeta(42) aggregates.

Insensitivity to Abeta42-lowering nonsteroidal anti-inflammatory drugs and gamma-secretase inhibitors is common among aggressive presenilin-1 mutations.

Abeta42-lowering nonsteroidal anti-inflammatory drugs (NSAIDs) constitute the founding members of a new class of gamma-secretase modulators that avoid side effects of pan-gamma-secretase inhibitors on NOTCH processing and function, holding promise as potential disease-modifying agents for Alzheimer disease (AD). These modulators are active in cell-free gamma-secretase assays indicating that they directly target the gamma-secretase complex. Additional support for this hypothesis was provided by the observation that certain mutations in presenilin-1 (PS1) associated with early-onset familial AD (FAD) change the cellular drug response to Abeta42-lowering NSAIDs.

Selective modulation of Abeta42 production in Alzheimer's disease: non-steroidal anti-inflammatory drugs and beyond.

The amyloid-beta (Abeta) peptides and in particular the longer, highly amyloidogenic isoform Abeta42 are believed by many to be the central disease-causing agents in Alzheimer's disease (AD). Consequently, academic and pharmaceutical laboratories have focused on elucidating the mechanisms of Abeta production and developing strategies to diminish Abeta formation for treatment or prevention of AD. The most substantial advances have been made with respect to inhibitors of the gamma-secretase enzyme, which catalyzes the final step in the generation of Abeta from the amyloid precursor protein (APP).

Inhibitors of Rho-kinase modulate amyloid-beta (Abeta) secretion but lack selectivity for Abeta42.

Certain non-steroidal anti-inflammatory drugs (NSAIDs) preferentially inhibit production of the amyloidogenic Abeta42 peptide, presumably by direct modulation of gamma-secretase activity. A recent report indicated that NSAIDs could reduce Abeta42 by inhibition of the small GTPase Rho, and a single inhibitor of Rho kinase (ROCK) mimicked the effects of Abeta42-lowering NSAIDs. To investigate whether Abeta42 reduction is a common property of ROCK inhibitors, we tested commercially available compounds in cell lines that were previously used to demonstrate the Abeta42-lowering activity of NSAIDs.