Age-dependent neurodegeneration resulting from widespread apoptosis of neurons and glia characterize the Drosophila Swiss Cheese (SWS) mutant. Neuropathy target esterase (NTE), the vertebrate homologue of SWS, reacts with organophosphates which initiate a syndrome of axonal degeneration. NTE is expressed in neurons and a variety of nonneuronal cell types in adults and fetal mice. To investigate the physiological functions of NTE, we inactivated its gene by targeted mutagenesis in embryonic stem cells. Heterozygous NTE ؉/؊ mice displayed a 50% reduction in NTE activity but underwent normal organ development. Complete inactivation of the NTE gene resulted in embryonic lethality, which became evident after gastrulation at embryonic day 9 postcoitum (E9). As early as E7.5, mutant embryos revealed growth retardation which did not reflect impaired cell proliferation but rather resulted from failed placental development; as a consequence, massive apoptosis within the developing embryo preceded its resorption. Histological analysis indicated that NTE is essential for the formation of the labyrinth layer and survival and differentiation of secondary giant cells. Additionally, impairment of vasculogenesis in the yolk sacs and embryos of null mutant conceptuses suggested that NTE is also required for normal blood vessel development.
Ap-2 transcription factors comprise a family of 5 closely related sequence-specific DNA binding proteins that play pivotal and non-redundant roles in embryonic organogenesis. To investigate the function of Ap-2δ, wδe analyzed its expression during embryogenesis and generated Ap-2δ-deficient mice. In line with the specific expression pattern of Ap-2δ in the mesencephalic tectum and the dorsal midbrain, Ap-2δ-deficient mice failed to maintain the colliculus inferior, a derivative of the dorsal midbrain, as a consequence of increased apoptotic cell death. To identify specific Ap-2δ target genes in cells of the developing dorsal midbrain, we performed whole genome analysis of cDNA expression levels. This approach identified a set of 12 putative target genes being expressed in the developing midbrain, including the transcription factors Pitx2, Mef2c, Bhlhb4 and Pou4f3. Using chromatin immunoprecipitation (CHIP) we showed that some of these genes are direct targets of Ap-2δ. Consistently, we demonstrate that Ap-2δ occupies and activates the Pou4f3 and Bhlhb4 promoters. In addition, known Pou4f3 target genes were downregulated in the posterior midbrain of Ap-2δ-deficient mice. Despite the absence of a central part of the auditory pathway, the presence of neuronal responses to sounds in the neocortex of Ap-2δ-deficient mice indicates that auditory information from the brainstem still reaches the neocortex. In summary, our data define Ap-2δ as an important transcription factor, specifying gene expression patterns required for the development of the posterior midbrain.
Mutations in the parkin gene encoding an E3 ligase are responsible for autosomal recessive ParkinsonÕs disease. Putative parkin substrates and interacting partners have been identified, but the molecular mechanism underlying parkin-related neurodegeneration is still unclear. We have identified the 20S proteasomal subunit a4 (synonyms: PSMA7, XAPC7, subunit alpha type 7) as a new interacting partner of parkin. The Cterminal IBR-RING domain of parkin and the C-terminal part of a4 were essential for the interaction. Biochemical studies revealed that a4 was not a substrate for parkin-dependent ubiquitylation. Putative functions of the interaction might therefore be substrate presentation to the proteasome or regulation of proteasomal activity. Full-length parkin and parkin lacking the Nterminal ubiquitin-like domain slightly increased the proteasomal activity in HEK 293T cells, in line with the latter hypothesis.
ObjectivesPatients with autoimmune inflammatory rheumatic diseases (AIRD) often have lower vaccination coverage rates compared with the general population, despite being disproportionately affected by infectious complications. We aim to systematically review the literature regarding vaccination willingness and hesitancy in AIRD.MethodsA scoping review was conducted in PubMed, EMBASE and the Cochrane Library in June 2021. Study selection was performed by two independent reviewers and data were extracted using a standardised form. Risk of bias was assessed using instruments from McMaster University. Identified barriers were categorised into the WHO’s measuring behavioural and social drivers (BeSD) of vaccination conceptual model.ResultsThe search yielded 1644 hits of which 30 publications were included (cross-sectional studies based on interviews (n=27) and intervention studies (n=3)). The majority of studies reported barriers to influenza and pneumococcal vaccination only (n=9) or in combination with another vaccination (n=8) from the patients’ perspective. Only one study assessed the view of rheumatologists. Coverage of domains matched to the BeSD model suggests a lack of awareness of infection risk by both patients and physicians. Patients mainly mentioned behavioural and social factors that negatively influenced their willingness to be vaccinated while physicians mentioned organisational deficits as major barriers.ConclusionsThe view on vaccination in patients with AIRD diverges between patients and rheumatologists. Our results show that in-depth counselling on vaccines is important for patients, whereas physicians need support in implementing specific immunisation recommendations. The themes identified provide a starting point for future interventions to improve vaccine rates in patients with AIRD.
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