Adenovirus Recruits Dynein by an Evolutionary Novel Mechanism Involving Direct Binding to pH-Primed Hexon

Following receptor-mediated uptake into endocytic vesicles and escape from the endosome, adenovirus is transported by cytoplasmic dynein along microtubules to the perinuclear region of the cell. How motor proteins are recruited to viruses for their own use has begun to be investigated only recently. We review here the evidence for a role for dynein and other motor proteins in adenovirus infectivity. We also discuss the implications of recent studies on the mechanism of dynein recruitment to adenovirus for understanding the relationship between pathogenic and physiological cargo recruitment and for the evolutionary origins of dynein-mediated adenovirus transport

Role of Microtubule Motor Proteins in Adenoviral Infections

Viruses have been described as a piece of nucleic acid surrounded by bad news. These bad news determine host specificity, pathogenicity, and virulence. In the case of adenovirus, a non-enveloped double-stranded DNA virus that causes self-limiting disease in healthy individuals but can cause severe and even fatal infection in immunocompromised patients, the bad news can be reduced to the viral capsid. The adenoviral capsid mainly consists of three proteins (fiber, penton base, hexon) that form a rigid shell to protect the viral genome outside of host cells. However, they are able to orchestrate a precise disassembly program initiated once the next susceptible cell is reached, leading to step-wise virus entry, controlled capsid disintegration, efficient DNA delivery, and production of progeny virus. Understanding adenovirus entry is not only beneficial for pathogenic but also therapeutic reasons since adenoviruses have become an increasingly popular vaccine and gene transfer vector due to their ability to infect a large array of dividing and post-mitotic cells, their large DNA capacity, and easy amplification. Attachment to cell surface receptors leads to cellular signaling events, some of which regulate receptor-mediated uptake into clathrin-coated pits. Conditions inside the endosome trigger escape of the virions from the organelle through membrane disruption 5-15 min post-infection and most capsids gain access to the nucleus about 30-45 min thereafter. Interestingly, adenovirus relies on the microtubule (MT) network, MT-dependent motor proteins, and virus-stimulated cAMP-activated kinase (protein kinase A, PKA) activity to traverse the cytoplasm during the critical intracellular transport phase between endosomal escape and nuclear pore complex attachment. The main virus transporter is the MT minus-end directed motor protein complex cytoplasmic dynein, which functions in organelle positioning, cell migration, cell division, and cell differentiation in uninfected cells. Cytoplasmic dynein subunits known to interact with physiological cargo also bind directly to the adenovirus capsid protein hexon, which remains with the viral genome until its delivery through the nuclear pore complex. Strikingly, for strong binding to cytoplasmic dynein, hexon requires an acidification step, indicating an additional functional role of the passage through the acidic endosomal lumen during entry, priming of hexon for cytoplasmic dynein binding. Here, we continue previous research of the hexon - dynein interaction and describe the determinants of dynein-mediated capsid transport in further detail. We show that the requirement for stimulated PKA activity on MT minus-end directed motility involves a PKA phosphorylation site in the dynein light intermediate chain 1 (LIC1). PKA phosphorylation or a phosphomimetic mutation increase hexon binding of LIC1 in vitro and RNAi rescue experiments confirm a clear role of PKA phosphorylation in adenovirus redistribution to the nucleus. To our surprise, the same phosphorylation site also plays a role in positioning of lysosomes/late endosomes (lyso/LE) a class of organelles under PKA control. However, in contrast to dynein-mediated viral cargo transport which is stimulated upon phosphorylation, lyso/LE motility in the minus-end direction is strongly reduced leading to lyso/LE dispersal into the periphery. Hence, during adenoviral infections, stimulation of PKA activity mediates two distinct functions, lyso/LE dispersal and efficient capsid transport.Remarkably, adenovirus transport is not only mediated by cytoplasmic dynein towards the cell center but also by opposite polarity motors towards the cell periphery leading to bidirectional capsid motility along MTs, similar to endogenous cargo. The motility pattern implies the involvement of members of the kinesin family, which are MT plus-end directed motor proteins regulating MT dynamics, cell division, and organelle transport in uninfected cells. We provide evidence for a direct capsid interaction with kinesin-1, which shows striking differences from the interaction between the capsid and cytoplasmic dynein. Kinesin binding appears to occur independent of low pH treatment of the virion and independent of hexon, but is very likely mediated through the capsid protein penton base. Exploring the physiological role of this interaction, subviral penton dodecahedra were purified from lysate of adenovirus infected cells and, after their specific binding to kinesin-1 but not cytoplasmic dynein was confirmed, were used for motility analysis in cultured hippocampal neurons. Dye-labeled penton dodecahedra show clear intracellular motility in live-cell microscopy. In addition, we also explored the pH dependent change in hexon affinity for cytoplasmic dynein by testing the viral capsid protein for structural changes at acidic pH conditions. In its native form inside the capsid or as soluble antigen, hexon is present as a tightly associated trimer, which is resistant to elevated temperature, high ionic strength, detergent treatment, and low pH. However, we now show that low pH treatment strongly increases the sensitivity of the trimeric structure to SDS, leading to hexon monomerization. These data indicate a subtle structural change in the hexon polypeptide upon low pH treatment, increasing dynein affinity and SDS-sensitivity. Taken together, the here presented work contributes to our understanding of adenovirus entry, especially during the cytoplasmic transport phase, and reveals mechanisms of finely orchestrated host-pathogen interactions at the evolutionary interface of viral attack and cellular host defense

Combining Prior Knowledge and Data for Robust Controller Design

We present a framework for systematically combining data of an unknown linear time-invariant system with prior knowledge on the system matrices or on the uncertainty for robust controller design. Our approach leads to linear matrix inequality (LMI) based feasibility criteria which guarantee stability and performance robustly for all closed-loop systems consistent with the prior knowledge and the available data. The design procedures rely on a combination of multipliers inferred via prior knowledge and learnt from measured data, where for the latter a novel and unifying disturbance description is employed. While large parts of the paper focus on linear systems and input-state measurements, we also provide extensions to robust output-feedback design based on noisy input-output data and against nonlinear uncertainties. We illustrate through numerical examples that our approach provides a flexible framework for simultaneously leveraging prior knowledge and data, thereby reducing conservatism and improving performance significantly if compared to black-box approaches to data-driven control

Professional Social Media Use Among Orthopedic and Trauma Surgeons in Germany: Cross-Sectional Questionnaire-Based Study

BACKGROUND Social media (SM) has been recognized as a professional communication tool in the field of orthopedic and trauma surgery that can enhance communication with patients and peers, and increase the visibility of research and offered services. The specific purposes of professional SM use and the benefits and concerns among orthopedic and trauma surgeons, however, remain unexplored. OBJECTIVE This study aims to demonstrate the specific uses of different SM platforms among orthopedic and trauma surgeons in Germany as well as the advantages and concerns. METHODS A web-based questionnaire was developed on the use of SM in a professional context by considering the current literature and the authors' topics of interest. The final questionnaire consisted of 33 questions and was distributed among German orthopedic and trauma surgeons via the mail distributor of the Berufsverband für Orthopädie und Unfallchirurgie (Professional Association of Orthopaedic Surgeons in Germany). The study was conducted between June and July 2022. A subgroup analysis was performed for sex (male vs female), age (<60 years vs ≥60 years), and type of workplace (practice vs hospital). RESULTS A total of 208 participants answered the questionnaire (male: n=166, 79.8%; younger than 60 years: n=146, 70.2%). In total, all of the participants stated that they use SM for professional purposes. In contrast, the stated specific uses of SM were low. Overall, the most used platforms were employment-oriented SM, messenger apps, and Facebook. Instagram emerged as a popular choice among female participants and participants working in hospital settings. The highest specific use of SM was for professional networking, followed by receiving and sharing health-related information. The lowest specific use was for education and the acquisition of patients. Conventional websites occupied a dominating position, exceeding the use of SM across all specific uses. The key benefit of SM was professional networking. Under 50% of the participants stated that SM could be used to enhance communication with their patients, keep up-to-date, or increase their professional visibility. In total, 65.5% (112/171) of participants stated that SM use was time-consuming, 43.9% (76/173) stated that they lacked application knowledge, and 45.1% (78/173) stated that they did not know what content to post. Additionally, 52.9% (91/172) mentioned medicolegal concerns. CONCLUSIONS Overall, SM did not seem to be used actively in the professional context among orthopedic and trauma surgeons in Germany. The stated advantages were low, while the stated concerns were high. Adequate education and information material are needed to elucidate the possible professional applications of SM and to address legal concerns

Role of kinesins in directed adenovirus transport and cytoplasmic exploration

Many viruses, including adenovirus, exhibit bidirectional transport along microtubules following cell entry. Cytoplasmic dynein is responsible for microtubule minus end transport of adenovirus capsids after endosomal escape. However, the identity and roles of the opposing plus end-directed motor(s) remain unknown. We performed an RNAi screen of 38 kinesins, which implicated Kif5B (kinesin-1 family) and additional minor kinesins in adenovirus 5 (Ad5) capsid translocation. Kif5B RNAi markedly increased centrosome accumulation of incoming Ad5 capsids in human A549 pulmonary epithelial cells within the first 30 min post infection, an effect dramatically enhanced by blocking Ad5 nuclear pore targeting using leptomycin B. The Kif5B RNAi phenotype was rescued by expression of RNAi-resistant Kif5A, B, or C, and Kif4A. Kif5B RNAi also inhibited a novel form of microtubule-based “assisted-diffusion” behavior which was apparent between 30 and 60 min p.i. We found the major capsid protein penton base (PB) to recruit kinesin-1, distinct from the hexon role we previously identified for cytoplasmic dynein binding. We propose that adenovirus uses independently recruited kinesin and dynein for directed transport and for a more random microtubule-based assisted diffusion behavior to fully explore the cytoplasm before docking at the nucleus, a mechanism of potential importance for physiological cargoes as well

Stand-alone percutaneous stent-kyphoplasty for thoracolumbar split and burst-split fractures

Introduction Traditionally, thoracolumbar split and burst-split fractures are treated with combined antero-posterior bi-segmental fusion procedures. Especially in the lower lumbar spine, such interventions are invasive and are associated with increased risk of neurological and vascular complications. This retrospective study aims to determine whether percutaneous stent-kyphoplasty is a viable treatment option for these injuries in terms of kyphotic angle correction and patient safety. Methods From Nov. 2014 to Dec. 2017, 25 consecutive patients (9 female, mean age 58 years) with 8 thoracolumbar split and 17 burst-split fractures (T11 to L5) of different etiology (7 high vs. 18 low energy trauma) were treated with percutaneous stent-kyphoplasty (SpineJack®). CT and/or MR imaging was performed preoperatively in all patients while radiographs were obtained postoperatively and at each follow-up. The mean follow-up was 176 days (SD 130). All cases were evaluated retrospectively for complications regarding nervous damage, LOS, duration of opioid intake, pain-VAS, return to work time and change of radiographic kyphotic angle. Results The mean kyphotic angle did not change from 1.1° (SD 9.2°) preoperatively to 1.1° (SD 7.9°) postoperatively. Radiologically, the mean increase of the kyphotic angle between surgery and the last follow-up was 2.65° (SD 4.2°). The mean pain-VAS was reduced to 1.8 postoperatively (SD 2.5, p = 0.03). The mean opioid intake duration was 4 days. Conclusion SpineJack®-kyphoplasty appears to be a safe and expeditious, minimally invasive treatment option for thoracolumbar split or burst-split fractures. It may be considered as an alternative to combined anterior-posterior instrumented bi-segmental fusion with its associated surgical morbidity

ECoG Beta Suppression and Modulation During Finger Extension and Flexion

Neural oscillations originate predominantly from interacting cortical neurons and consequently reflect aspects of cortical information processing. However, their functional role is not yet fully understood and their interpretation is debatable. Amplitude modulations (AMs) in alpha (8–12 Hz), beta (13–30 Hz), and high gamma (70–150 Hz) band in invasive electrocorticogram (ECoG) and non-invasive electroencephalogram (EEG) signals change with behavior. Alpha and beta band AMs are typically suppressed (desynchronized) during motor behavior, while high gamma AMs highly correlate with the behavior. These two phenomena are successfully used for functional brain mapping and brain-computer interface (BCI) applications. Recent research found movement-phase related AMs (MPA) also in high beta/low gamma (24–40 Hz) EEG rhythms. These MPAs were found by separating the suppressed AMs into sustained and dynamic components. Sustained AM components are those with frequencies that are lower than the motor behavior. Dynamic components those with frequencies higher than the behavior. In this paper, we study ECoG beta/low gamma band (12–30 Hz/30–42 Hz) AM during repetitive finger movements addressing the question whether or not MPAs can be found in ECoG beta band. Indeed, MPA in the 12–18 Hz and 18–24 Hz band were found. This additional information may lead to further improvements in ECoG-based prediction and reconstruction of motor behavior by combining high gamma AM and beta band MPA

Perspectives of Patients With Orthopedic Trauma on Fully Automated Digital Physical Activity Measurement at Home: Cross-sectional Survey Study

BACKGROUND: The automated digital surveillance of physical activity at home after surgical procedures could facilitate the monitoring of postoperative follow-up, reduce costs, and enhance patients' satisfaction. Data on the willingness of patients with orthopedic trauma to undergo automated home surveillance postoperatively are lacking. OBJECTIVE: The aims of this study were to assess whether patients with orthopedic trauma would be generally willing to use the proposed automated digital home surveillance system and determine what advantages and disadvantages the system could bring with it. METHODS: Between June 2021 and October 2021, a survey among outpatients with orthopedic trauma who were treated at a European level 1 trauma center was conducted. The only inclusion criterion was an age of at least 16 years. The paper questionnaire first described the possibility of fully automated movement and motion detection (via cameras or sensors) at home without any action required from the patient. The questionnaire then asked for the participants' demographics and presented 6 specific questions on the study topic. RESULTS: In total, we included 201 patients whose mean age was 46.9 (SD 18.6) years. Most of the assessed patients (124/201, 61.7%) were male. Almost half of the patients (83/201, 41.3%) were aged between 30 and 55 years. The most stated occupation was a nine-to-five job (62/199, 30.8%). The majority of the participants (120/201, 59.7%) could imagine using the proposed measurement system, with no significant differences among the genders. An insignificant higher number of younger patients stated that they would use the automated surveillance system. No significant difference was seen among different occupations (P=.41). Significantly more young patients were using smartphones (P=.004) or electronic devices with a camera (P=.008). Less than half of the surveyed patients (95/201, 47.3%) stated that they were using tracking apps. The most stated advantages were fewer physician visits (110/201, 54.7%) and less effort (102/201, 50.7%), whereas the most prevalent disadvantage was the missing physician-patient contact (144/201, 71.6%). Significantly more patients with a part-time job or a nine-to-five job stated that data analysis contributes to medical progress (P=.047). CONCLUSIONS: Most of the assessed participants (120/201, 59.7%) stated that they would use the automated digital measurement system to observe their postoperative follow-up and recovery. The proposed system could be used to reduce costs and ease hospital capacity issues. In order to successfully implement such systems, patients' concerns must be addressed, and further studies on the feasibility of these systems are needed

Impact of the first COVID-19 shutdown on traumatological patient volumes in Switzerland

Background The coronavirus has caused a worldwide pandemic with serious impacts on our healthcare systems. Many countries experienced a decline in traumatological patient volume. The aim of this study is to evaluate the impact of the first lockdown on traumatological patient volume in Switzerland. Methods We retrospectively used a prospective national quality measurement database. We compared the period of the first lockdown in Switzerland from March 17 to April 26, 2020 to the same period in the years 2018 and 2019. Included were all adult patients with any S-code (trauma) according to the International Classification of Diseases. Results In total, we assessed 3874 patients (1779 in the year 2018, 1303 in the year 2019, and 792 in the year 2020) with a mean age of 61 ± 21 years. The patients during the lockdown period had significantly more injuries to the hip and forearm, had more comorbidities, and were more likely to have statutory insurance. During the lockdown period, more thromboembolism prophylaxis or anticoagulation was applied, and more patients needed antibiotic treatment. Conclusions The present study demonstrated a 40–55% reduction in patient volume during the lockdown period in Switzerland compared to the previous years. The in-hospital mortality and complication rate during the lockdown period remained stable. This study suggests that in-hospital care for trauma patients in Switzerland was not substantially affected by the first lockdown