Antiretroviral medications disrupt microglial phagocytosis of β-amyloid and increase its production by neurons: Implications for HIV-associated neurocognitive disorders

Up to 50% of long-term HIV infected patients, including those with systemically well-controlled infection, commonly experience memory problems and slowness, difficulties in concentration, planning, and multitasking. Deposition of Aβ plaques is also a common pathological feature of HIV infection. However, it is not clear whether this accumulation is due to AD-like processes, HIV-associated immunosuppression, Tat protein-induced Aβ elevations, and/or the effects of single highly active antiretroviral therapy (ART). Here we evaluated the effects of several ART medications (Zidovudine, Lamivudine, Indinavir, and Abacavir) alone and in combination on: 1) Aβ1-40, 42 generation in murine N2a cells transfected with the human "Swedish" mutant form of APP; 2) microglial phagocytosis of FITC-Aβ1-42 peptides in cultured murine N9 microglia. We report for the first time that these antiretroviral compounds (10 μM) generally increase Aβ generation (~50-200%) in SweAPP N2a cells and markedly inhibit microglial phagocytosis of FITC-Aβ1-42 peptides in murine microglia. The most significant amyloidogenic effects were observed with combined ART (p < 0.05); suggesting certain ART medications may have additive amyloidogenic effects when combined. As these antiretroviral compounds are capable of penetrating the blood brain barrier and reaching the concentrations employed in the in vitro studies, these findings raise the possibility that ART may play a casual role in the elevated Aβ found in the brains of those infected with HIV. Therefore these compounds may consequently contribute to cognitive decline observed in HIV associated neurocognitive disorders (HAND)

High-throughput isolation and characterization of untagged membrane protein complexes: outer membrane complexes of Desulfovibrio vulgaris.

Cell membranes represent the "front line" of cellular defense and the interface between a cell and its environment. To determine the range of proteins and protein complexes that are present in the cell membranes of a target organism, we have utilized a "tagless" process for the system-wide isolation and identification of native membrane protein complexes. As an initial subject for study, we have chosen the Gram-negative sulfate-reducing bacterium Desulfovibrio vulgaris. With this tagless methodology, we have identified about two-thirds of the outer membrane- associated proteins anticipated. Approximately three-fourths of these appear to form homomeric complexes. Statistical and machine-learning methods used to analyze data compiled over multiple experiments revealed networks of additional protein-protein interactions providing insight into heteromeric contacts made between proteins across this region of the cell. Taken together, these results establish a D. vulgaris outer membrane protein data set that will be essential for the detection and characterization of environment-driven changes in the outer membrane proteome and in the modeling of stress response pathways. The workflow utilized here should be effective for the global characterization of membrane protein complexes in a wide range of organisms

Advance care planning in chronic kidney disease: a survey of current practice in Australia

Aim: Advance care planning (ACP) in nephrology is widely advocated but not always implemented. The aims of this study were to describe current ACP practice and identify barriers/facilitators and perceived need for health professional education and chronic kidney disease (CKD)-specific approaches. Methods: An anonymous cross-sectional survey was administered online. Nephrology health professionals in Australia and New Zealandwere recruited via professional societies, email lists and nephrology conferences. Multiple regression explored the influence of respondents’ attributes on extent of involvement in ACP and willingness to engage in future. Results: A total of 375 respondents included nephrologists (23%), nurses (65%), social workers (4%) and others (8%) with 54% indicated that ACP at their workplace was performed ad hoc and 61% poorly. Perceived barriers included patient/family discomfort (84%), difficulty engaging families (83%), lack of clinician expertise (83%) and time (82%), health professional discomfort (72%), cultural/language barriers (65%), lack of private space (61%) and lack of formal policy/procedures (60%). Respondents overwhelmingly endorsed the need for more dialysis-specific ACP programs (96%) and education (95%). Whilst 85% thought ACP would be optimally performed by specially trained staff, comments emphasized that all clinicians should have a working proficiency. Respondents who were more willing to engage in future ACP tended to be non-physicians (odds ratio (OR) 4.96, 95% confidence intervals (CI) 1.74–14.07) and reported a greater need for CKD-specific ACP materials (OR 10.88, 95% CI 2.38–49.79). Conclusion: Advance care planning in nephrology needs support through education and CKD-specific resources. Endorsement by nephrologists is important. A multidisciplinary approach with a gradient of ACP expertise is also recommended

Transmission of SARS-CoV-2 from humans to animals and potential host adaptation

SARS-CoV-2, the causative agent of the COVID-19 pandemic, can infect a wide range of mammals. Since its spread in humans, secondary host jumps of SARS-CoV-2 from humans to multiple domestic and wild populations of mammals have been documented. Understanding the extent of adaptation to these animal hosts is critical for assessing the threat that the spillback of animal-adapted SARS-CoV-2 into humans poses. We compare the genomic landscapes of SARS-CoV-2 isolated from animal species to that in humans, profiling the mutational biases indicative of potentially different selective pressures in animals. We focus on viral genomes isolated from mink (Neovison vison) and white-tailed deer (Odocoileus virginianus) for which multiple independent outbreaks driven by onward animal-to-animal transmission have been reported. We identify five candidate mutations for animal-specific adaptation in mink (NSP9_G37E, Spike_F486L, Spike_N501T, Spike_Y453F, ORF3a_L219V), and one in deer (NSP3a_L1035F), though they appear to confer a minimal advantage for human-to-human transmission. No considerable changes to the mutation rate or evolutionary trajectory of SARS-CoV-2 has resulted from circulation in mink and deer thus far. Our findings suggest that minimal adaptation was required for onward transmission in mink and deer following human-to-animal spillover, highlighting the 'generalist' nature of SARS-CoV-2 as a mammalian pathogen

Acceptability, benefits, and challenges of video consulting: a qualitative study in primary care

Background People increasingly communicate online, using visual communication mediums such as Skype and FaceTime. Growing demands on primary care services mean that new ways of providing patient care are being considered. Video consultation (VC) over the internet is one such mode. Aim To explore patients’ and clinicians’ experiences of VC. Design and setting Semi-structured interviews in UK primary care. Method Primary care clinicians were provided with VC equipment. They invited patients requiring a follow-up consultation to an online VC using the Attend Anywhere web-based platform. Participating patients required a smartphone, tablet, or video-enabled computer. Following VCs, semi-structured interviews were conducted with patients (n = 21) and primary care clinicians (n = 13), followed by a thematic analysis. Results Participants reported positive experiences of VC, and stated that VC was particularly helpful for them as working people and people with mobility or mental health problems. VCs were considered superior to telephone consultations in providing visual cues and reassurance, building rapport, and improving communication. Technical problems, however, were common. Clinicians felt, for routine use, VCs must be more reliable and seamlessly integrated with appointment systems, which would require upgrading of current NHS IT systems. Conclusion The visual component of VCs offers distinct advantages over telephone consultations. When integrated with current systems VCs can provide a time-saving alternative to face-to-face consultations when formal physical examination is not required, especially for people who work. Demand for VC services in primary care is likely to rise, but improved technical infrastructure is required to allow VC to become routine. However, for complex or sensitive problems face-to-face consultations remain preferable

The material properties of a bacterial-derived biomolecular condensate tune biological function in natural and synthetic systems

Intracellular phase separation is emerging as a universal principle for organizing biochemical reactions in time and space. It remains incompletely resolved how biological function is encoded in these assemblies and whether this depends on their material state. The conserved intrinsically disordered protein PopZ forms condensates at the poles of the bacterium Caulobacter crescentus, which in turn orchestrate cell-cycle regulating signaling cascades. Here we show that the material properties of these condensates are determined by a balance between attractive and repulsive forces mediated by a helical oligomerization domain and an expanded disordered region, respectively. A series of PopZ mutants disrupting this balance results in condensates that span the material properties spectrum, from liquid to solid. A narrow range of condensate material properties supports proper cell division, linking emergent properties to organismal fitness. We use these insights to repurpose PopZ as a modular platform for generating tunable synthetic condensates in human cells

Heme oxygenase-1 deficiency alters erythroblastic Island formation, steady-state erythropoiesis and red blood cell lifespan in mice

Heme oxygenase-1 is critical for iron recycling during red blood cell turnover, whereas its impact on steady-state erythropoiesis and red blood cell lifespan is not known. We show here that in 8- to 14-week old mice, heme oxygenase- 1 deficiency adversely affects steady-state erythropoiesis in the bone marrow. This is manifested by a decrease in Ter-119+-erythroid cells, abnormal adhesion molecule expression on macrophages and erythroid cells, and a greatly diminished ability to form erythroblastic islands. Compared with wild-type animals, red blood cell size and hemoglobin content are decreased, while the number of circulating red blood cells is increased in heme oxygenase-1 deficient mice, overall leading to microcytic anemia. Heme oxygenase-1 deficiency increases oxidative stress in circulating red blood cells and greatly decreases the frequency of macrophages expressing the phosphatidylserine receptor Tim4 in bone marrow, spleen and liver. Heme oxygenase-1 deficiency increases spleen weight and Ter119+-erythroid cells in the spleen, although α4β1-integrin expression by these cells and splenic macrophages positive for vascular cell adhesion molecule 1 are both decreased. Red blood cell lifespan is prolonged in heme oxygenase-1 deficient mice compared with wild-type mice. Our findings suggest that while macrophages and relevant receptors required for red blood cell formation and removal are substantially depleted in heme oxygenase- 1 deficient mice, the extent of anemia in these mice may be ameliorated by the prolonged lifespan of their oxidatively stressed erythrocytes