The Cell Biology of the Retinal Pigment Epithelium

The retinal pigment epithelium (RPE), a monolayer of post-mitotic polarized epithelial cells, strategically situated between the photoreceptors and the choroid, is the primary caretaker of photoreceptor health and function. Dysfunction of the RPE underlies many inherited and acquired diseases that cause permanent blindness. Decades of research have yielded valuable insight into the cell biology of the RPE. In recent years, new technologies such as live-cell imaging have resulted in major advancement in our understanding of areas such as the daily phagocytosis and clearance of photoreceptor outer segment tips, autophagy, endolysosome function, and the metabolic interplay between the RPE and photoreceptors. In this review, we aim to integrate these studies with an emphasis on appropriate models and techniques to investigate RPE cell biology and metabolism, and discuss how RPE cell biology informs our understanding of retinal disease. © 2020 Elsevier Lt

A 2cM genome-wide scan of European Holstein cattle affected by classical BSE

<p>Abstract</p> <p>Background</p> <p>Classical bovine spongiform encephalopathy (BSE) is an acquired prion disease that is invariably fatal in cattle and has been implicated as a significant human health risk. Polymorphisms that alter the prion protein of sheep or humans have been associated with variations in transmissible spongiform encephalopathy susceptibility or resistance. In contrast, there is no strong evidence that non-synonymous mutations in the bovine prion gene (<it>PRNP</it>) are associated with classical BSE disease susceptibility. However, two bovine <it>PRNP </it>insertion/deletion polymorphisms, one within the promoter region and the other in intron 1, have been associated with susceptibility to classical BSE. These associations do not explain the full extent of BSE susceptibility, and loci outside of <it>PRNP </it>appear to be associated with disease incidence in some cattle populations. To test for associations with BSE susceptibility, we conducted a genome wide scan using a panel of 3,072 single nucleotide polymorphism (SNP) markers on 814 animals representing cases and control Holstein cattle from the United Kingdom BSE epidemic.</p> <p>Results</p> <p>Two sets of BSE affected Holstein cattle were analyzed in this study, one set with known family relationships and the second set of paired cases with controls. The family set comprises half-sibling progeny from six sires. The progeny from four of these sires had previously been scanned with microsatellite markers. The results obtained from the current analysis of the family set yielded both some supporting and new results compared with those obtained in the earlier study. The results revealed 27 SNPs representing 18 chromosomes associated with incidence of BSE disease. These results confirm a region previously reported on chromosome 20, and identify additional regions on chromosomes 2, 14, 16, 21 and 28. This study did not identify a significant association near the <it>PRNP </it>in the family sample set. The only association found in the <it>PRNP </it>region was in the case-control sample set and this was not significant after multiple test correction. The genome scan of the case-control animals did not identify any associations that passed a stringent genome-wide significance threshold.</p> <p>Conclusions</p> <p>Several regions of the genome are statistically associated with the incidence of classical BSE in European Holstein cattle. Further investigation of loci on chromosomes 2, 14, 16, 20, 21 and 28 will be required to uncover any biological significance underlying these marker associations.</p

Water reform for all: a national response to a water emergency

Australia’s water reform project is failing to fully deliver for all Australians. With the COVID-19 pandemic, long-accepted approaches are being questioned in many areas of national policy. This also applies to water reform. The Australian bush fires of 2019-20 mean that Australians can no longer ignore the devastating impacts of natural disasters in a dryer and warmer country. The new normal is that it will continue to get hotter and, where most Australians live, it will get drier. Rainfall will become more unpredictable and extreme weather events, such as cyclones, more intense. These conditions will make it even more difficult for water managers who, during repeated and prolonged droughts, are struggling to manage the intensification of Australia’s ‘boom and bust’ water availability. To cope with Australia’s water emergency, we need to extract less water and ensure our rivers, lakes and wetlands have the water they need at the right time to deliver ecosystem functions and services: water supply for people and livestock; habitat for plants and animals; water quality and flood regulation; nutrient cycling; recreation; and, importantly, access and use of water by all Australians. Here, we propose six principles to provide a foundation for Water Reform For All: (1) establish shared visions and goals that are community-based and co-produced; (2) develop clarity of roles and responsibilities, including an ability and willingness to revise adaptation plans, actions and visions; (3) understand adaptation as a means to respond to persistent escalation of stresses, including drought, climate change, bush fires and governance failures; (4) invest in advanced technology to monitor, predict and understand changes in water availability in a transforming Australian landscape and grow our shared knowledge as a basis for adaptive water reform; (5) integrate bottom-up community-based adaptation, including from Indigenous communities, into renewed arrangements for water governance; and (6) implement management actions as experiments for ‘learning to do things differently’. These six water reform principles require national conversations, supported by our collective capacity to imagine alternative futures and apply this to decision-making, along with recognition and inclusion of First Peoples’ values and knowledge of land, water and fire. Without national conversations on water reform and deliberative processes, we expect that Australia’s water emergency will continue and, with climate change, get worse. This is a future that we can, and must, change for the benefit of all Australians.The Australian National Universit

A second generation radiation hybrid map to aid the assembly of the bovine genome sequence

BACKGROUND: Several approaches can be used to determine the order of loci on chromosomes and hence develop maps of the genome. However, all mapping approaches are prone to errors either arising from technical deficiencies or lack of statistical support to distinguish between alternative orders of loci. The accuracy of the genome maps could be improved, in principle, if information from different sources was combined to produce integrated maps. The publicly available bovine genomic sequence assembly with 6× coverage (Btau_2.0) is based on whole genome shotgun sequence data and limited mapping data however, it is recognised that this assembly is a draft that contains errors. Correcting the sequence assembly requires extensive additional mapping information to improve the reliability of the ordering of sequence scaffolds on chromosomes. The radiation hybrid (RH) map described here has been contributed to the international sequencing project to aid this process. RESULTS: An RH map for the 30 bovine chromosomes is presented. The map was built using the Roslin 3000-rad RH panel (BovGen RH map) and contains 3966 markers including 2473 new loci in addition to 262 amplified fragment-length polymorphisms (AFLP) and 1231 markers previously published with the first generation RH map. Sequences of the mapped loci were aligned with published bovine genome maps to identify inconsistencies. In addition to differences in the order of loci, several cases were observed where the chromosomal assignment of loci differed between maps. All the chromosome maps were aligned with the current 6× bovine assembly (Btau_2.0) and 2898 loci were unambiguously located in the bovine sequence. The order of loci on the RH map for BTA 5, 7, 16, 22, 25 and 29 differed substantially from the assembled bovine sequence. From the 2898 loci unambiguously identified in the bovine sequence assembly, 131 mapped to different chromosomes in the BovGen RH map. CONCLUSION: Alignment of the BovGen RH map with other published RH and genetic maps showed higher consistency in marker order and chromosome assignment than with the current 6× sequence assembly. This suggests that the bovine sequence assembly could be significantly improved by incorporating additional independent mapping information

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Latency Antigen α-Crystallin Based Vaccination Imparts a Robust Protection against TB by Modulating the Dynamics of Pulmonary Cytokines

BACKGROUND: Efficient control of tuberculosis (TB) requires development of strategies that can enhance efficacy of the existing vaccine Mycobacterium bovis Bacille Calmette Guerin (BCG). To date only a few studies have explored the potential of latency-associated antigens to augment the immunogenicity of BCG. METHODS/PRINCIPAL FINDINGS: We evaluated the protective efficacy of a heterologous prime boost approach based on recombinant BCG and DNA vaccines targeting α-crystallin, a prominent latency antigen. We show that "rBCG prime-DNA boost" strategy (R/D) confers a markedly superior protection along with reduced pathology in comparison to BCG vaccination in guinea pigs (565 fold and 45 fold reduced CFU in lungs and spleen, respectively, in comparison to BCG vaccination). In addition, R/D regimen also confers enhanced protection in mice. Our results in guinea pig model show a distinct association of enhanced protection with an increased level of interleukin (IL)12 and a simultaneous increase in immuno-regulatory cytokines such as transforming growth factor (TGF)β and IL10 in lungs. The T cell effector functions, which could not be measured in guinea pigs due to technical limitations, were characterized in mice by multi-parameter flow cytometry. We show that R/D regimen elicits a heightened multi-functional CD4 Th1 cell response leading to enhanced protection. CONCLUSIONS/SIGNIFICANCE: These results clearly indicate the superiority of α-crystallin based R/D regimen over BCG. Our observations from guinea pig studies indicate a crucial role of IL12, IL10 and TGFβ in vaccine-induced protection. Further, characterization of T cell responses in mice demonstrates that protection against TB is predictable by the frequency of CD4 T cells simultaneously producing interferon (IFN)γ, tumor necrosis factor (TNF)α and IL2. We anticipate that this study will not only contribute toward the development of a superior alternative to BCG, but will also stimulate designing of TB vaccines based on latency antigens

Inhibition of Nipah Virus Infection In Vivo: Targeting an Early Stage of Paramyxovirus Fusion Activation during Viral Entry

In the paramyxovirus cell entry process, receptor binding triggers conformational changes in the fusion protein (F) leading to viral and cellular membrane fusion. Peptides derived from C-terminal heptad repeat (HRC) regions in F have been shown to inhibit fusion by preventing formation of the fusogenic six-helix bundle. We recently showed that the addition of a cholesterol group to HRC peptides active against Nipah virus targets these peptides to the membrane where fusion occurs, dramatically increasing their antiviral effect. In this work, we report that unlike the untagged HRC peptides, which bind to the postulated extended intermediate state bridging the viral and cell membranes, the cholesterol tagged HRC-derived peptides interact with F before the fusion peptide inserts into the target cell membrane, thus capturing an earlier stage in the F-activation process. Furthermore, we show that cholesterol tagging renders these peptides active in vivo: the cholesterol-tagged peptides cross the blood brain barrier, and effectively prevent and treat in an established animal model what would otherwise be fatal Nipah virus encephalitis. The in vivo efficacy of cholesterol-tagged peptides, and in particular their ability to penetrate the CNS, suggests that they are promising candidates for the prevention or therapy of infection by Nipah and other lethal paramyxoviruses