Parvoviruses cause nuclear envelope breakdown by activating key enzymes of mitosis

Disassembly of the nuclear lamina is essential in mitosis and apoptosis requiring multiple coordinated enzymatic activities in nucleus and cytoplasm. Activation and coordination of the different activities is poorly understood and moreover complicated as some factors translocate between cytoplasm and nucleus in preparatory phases. Here we used the ability of parvoviruses to induce nuclear membrane breakdown to understand the triggers of key mitotic enzymes. Nuclear envelope disintegration was shown upon infection, microinjection but also upon their application to permeabilized cells. The latter technique also showed that nuclear envelope disintegration was independent upon soluble cytoplasmic factors. Using time-lapse microscopy, we observed that nuclear disassembly exhibited mitosis-like kinetics and occurred suddenly, implying a catastrophic event irrespective of cell- or type of parvovirus used. Analyzing the order of the processes allowed us to propose a model starting with direct binding of parvoviruses to distinct proteins of the nuclear pore causing structural rearrangement of the parvoviruses. The resulting exposure of domains comprising amphipathic helices was required for nuclear envelope disintegration, which comprised disruption of inner and outer nuclear membrane as shown by electron microscopy. Consistent with Ca⁺⁺ efflux from the lumen between inner and outer nuclear membrane we found that Ca⁺⁺ was essential for nuclear disassembly by activating PKC. PKC activation then triggered activation of cdk-2, which became further activated by caspase-3. Collectively our study shows a unique interaction of a virus with the nuclear envelope, provides evidence that a nuclear pool of executing enzymes is sufficient for nuclear disassembly in quiescent cells, and demonstrates that nuclear disassembly can be uncoupled from initial phases of mitosis.

Parvoviruses are small non-enveloped DNA viruses successfully used in gene therapy. Their nuclear replication requires transit of the nuclear envelope. Analyzing the interaction between parvoviruses and the nucleus, we showed that despite their small size, they did not traverse the nuclear pore, but attached directly to proteins of the nuclear pore complex. We observed that this binding induced structural changes of the parvoviruses and that the structural rearrangement was essential for triggering a signal cascade resulting in disintegration of the nuclear envelope. Physiologically such nuclear envelope breakdown occurs late during prophase of mitosis. Our finding that the parvovirus-mediated nuclear envelope breakdown also occurred in the absence of soluble cytosolic factors allowed us to decipher the intra nuclear pathways involved in nuclear envelope destabilization. Consistently with the physiological disintegration we found that key enzymes of mitosis were essential and we further identified Ca⁺⁺ as the initial trigger. Thus our data not only show a unique pathway of how a DNA virus interacts with the nucleus but also describes a virus-based system allowing the first time to analyze selectively the intranuclear pathways leading to nuclear envelope disintegration.

Implementation and performance of haemovigilance systems in 10 sub-saharan African countries is sub-optimal

Background

Haemovigilance is an important element of blood regulation. It includes collecting and evaluating the information on adverse events resulting from the use of blood and blood components with the aim to improve donor and patient safety. We describe the results of the pilot of the integrated GBT+ Blood for the haemovigilance function in 10 sub-Saharan African countries.

Methods

We piloted the integrated WHO Global Benchmarking Tool plus Blood (GBT+ Blood) to assess the haemovigilance function of national regulatory authorities (NRAs) in Ethiopia, Kenya, Malawi, Nigeria, Liberia, Rwanda, South Africa, Tanzania, Uganda, and Zimbabwe. Data obtained from documents and face to face interviews were used to determine the status of implementation and performance of the following six indicators; legal provisions regulations and guidelines, organisation and governance, human resources, regulatory processes, transparency and accountability and finally, monitoring progress and assessing impact, by estimating median scores across 20 sub-indicators. In addition, a cluster analysis was performed.

Results

The countries showed inter-organisation variability in implementation and performance of the haemovigilance function. The overall median score (all sub-indicators) was 44 % (range: 7.5 % - 70 %). The lowest average performance scores were for the arrangement for effective organisation and coordination (35 %) and human resources (35 %) indicators. The highest average scores were observed for the mechanism to promote transparency and mechanism to monitor regulatory performance indicators (50 % and 60 %, respectively). We identified clusters of best-implemented sub-indicators from the procedures for haemovigilance and poorly implemented sub-indicators from the legal provisions, regulations and guidelines for haemovigilance and human resources.

Conclusions

Implementation of sub-indicators and performance of haemovigilance systems varied greatly for all countries with a few countries performing reasonably well in the implementation of some sub-indicators under procedures for haemovigilance. Most countries were poorly implementing sub-indicators in the legal provisions, arrangement for effective organisation and human resources indicators. The legislative provisions in most countries were at a nascent stage. There is a need to set up targeted and customised technical support coupled with prioritised interventions to strengthen the capacities of NRAs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-07235-0.

INNOVATIONS IN ARTIFICIAL ORGANS AND TISSUE ENGINEERING: FROM 3D PRINTING TO STEM CELL THERAPY

"Every year, many individuals with tissue or organ problems require urgent care due to medical emergencies, burns, congenital anomalies, and other causes". Regenerative medicine was created because there aren't enough donors, issues with graft rejection, and insufficient organs or tissues for patients to replace, repair, and regenerate. However, significant tissue defects are difficult to fill with injections alone, making stem cell therapy a crucial component of the area of regenerative medicine. To achieve the intended outcome, the researchers combine stem cells with three-dimensional (3D) printed organs tissue engineering scaffolding. These scaffolds can resemble bone, cartilage, or "extracellular matrix (ECM)" in that they provide structural support and promote adhesion, proliferation, and differentiation, finally resulting in the production of functional tissues or organs. In this study on stem cell regenerative medicine, the therapeutic focused mostly on scaffolding for 3D printed organ tissue engineering. The following applications are demonstrated and compared using various 3D printing processes and starting materials. Then, we go over the benefits of 3D printing over conventional methods, touch on certain issues and restrictions, and make some assumptions about potential applications in the future.

Bupropion Increases Rate of Smoking Abstinence in Smokers with Schizophrenia: A Systematic Review and Meta-analysis of Randomised Trial Data

Aims:

In patients with schizophrenia, higher rates of tobacco dependency contribute significantly to increased morbidity and mortality of various physical illnesses. However, evidence for treatment of nicotine addiction in these patients is uncertain. We performed a systematic review of the effectiveness and safety of bupropion (Zyban) for smoking cessation in schizophrenia.

Method:

We searched databases and conference proceedings for reports of randomised controlled trials (RCTs) in all languages, comparing bupropion with placebo or with a different therapeutic control in adult smokers with schizophrenia. Eligibility and quality of RCTs were independently assessed by two reviewers. Results are synthesised using a random effects model and expressed as Risk Ratio (RR) and mean difference (MD), both with 95% confidence interval (CI).

Results:

16 reports from six RCTs were included (258 participants). Smoking cessation rates after bupropion were significantly higher than placebo at the end of bupropion treatment (RR 2.56, CI 1.46 to 4.50) and at six months (RR 2.82, CI 1.04 to 7.69). Expired carbon monoxide level was significantly lower with bupropion at the end of therapy (MD -5.39ppm, CI -7.43 to -3.34ppm) but the effect was not sustained at six months (p=0.33). Positive and negative symptoms were not significantly different between bupropion and placebo group, but depressive symptoms were significantly reduced with bupropion at the end of treatment. There were no seizures reported with bupropion use.

Conclusion:

Our review suggests that bupropion increases the rates of smoking abstinence in smokers with schizophrenia, without jeopardising their mental state.