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Main protease of SARS-CoV-2 (Mpro) is the most promising drug target against coronaviruses due to its essential role in virus replication. With newly emerging variants there is a concern that mutations in Mpromay alter structural and functional properties of protease and subsequently the potency of existing and potential antivirals. We explored the effect of 31 mutations belonging to 5 variants of concern (VOC) on catalytic parameters and substrate specificity, which revealed changes in substrate binding and rate of cleavage of a viral peptide. Crystal structures of 11 Mpromutants provided structural insight into their altered functionality. Additionally, we show Mpromutations influence proteolysis of an immunomodulatory host protein Galectin-8 (Gal-8) and subsequent significant decrease in cytokine secretion, providing evidence for alterations in escape of host-antiviral mechanisms. Accordingly, mutations associated with the highly virulent Delta VOC resulted in significant increase in Gal-8 cleavage. Importantly, IC50s of nirmatrelvir (Pfizer) and our irreversible inhibitor AVI-8053 demonstrated no changes in potency for both drugs for all mutants, suggesting Mprowill remain a high-priority antiviral drug candidate as SARS-CoV-2 evolves.

Background: Myocardial hypertrophy and dilation are key features of cardiomyopathies and involve several cellular and molecular events. ADAMs (a disintegrin and metalloproteinases) are membrane-bound proteinases with diverse functions whose role in heart disease remains underexplored. ADAM15 is expressed in the heart and is downregulated in the failing human heart. We investigated the role ADAM15 in pressure overload cardiomyopathy. Methods: We assessed ADAM15 levels in myocardial specimens from patients. Its direct role in pressure overload was investigated by subjecting wildtype and Adam15 -deficient mice to transverse aortic constriction (TAC). Results: ADAM15 levels did not change in patients with concentric hypertrophy, but markedly decreased in eccentric hypertrophy and heart failure. Loss of ADAM15 alone did not cause cardiomyopathy in mice (1 year old). After TAC, Adam15 -/- mice exhibited worsened eccentric hypertrophy and dilation with greater increase in hypertrophy markers (pJNK, pERK1/2; Nppb, Nppa , Myh7 , Acta1 ) compared with wildtype-TAC. Expression of integrin-α7 (but not integrin β1) increased significantly more in Adam15 -/- -TAC hearts, while the interaction of these integrins with basement membrane (laminin), decreased consistent with worsened left ventricle dilation. In vitro, ADAM15 knockdown increased cardiomyocyte hypertrophy in response to mechanical stretch. Adam15 -/- -TAC hearts exhibited increased calcineurin activity and de-phosphorylation of nuclear factor of activated T cells. Calcineurin inhibition (cyclosporin-A) blocked the excess hypertrophy and dilation in Adam15 -/- -TAC mice. Proteome profiling demonstrated the increased abundance of the key proteins linked to worsened DCM in Adam15 -/- -TAC. Conclusion: This is the first report demonstrating that ADAM15 can suppress hypertrophy through regulating the integrin-laminin interaction and the calcineurin pathway.

In the context of GNSS L5/E5a interference environment dominated by DME/TACAN and JTIDS/MIDS pulses, RTCA DO-292 [1] proposes to implement a temporal blanker mechanism to mitigate the detrimental impact of the pulsed interference signals on the nominal functioning of a generic GNSS receiver. Moreover, RTCA DO-292 [1] also proposes a model to compute the received useful signal C/N_0 degradation due to the interference signals by increasing the noise power spectrum density (PSD) N_0, called the effective N_0, N_0_eff, where the N_0 increase is expressed as a function of the blanker duty cycle, bdc, and the equivalent noise level contribution of the nonblanked interference, E_I . However, the proposed computation of these two terms in RTCA DO-292 [1] makes some assumptions or neglect some effects which may decrease the final accuracy of the computation. On one hand, the collisions between pulses are not completely modelled. On the other hand, the effect of the time-domain blanker mechanism over the pulsed interference signal PSD is over bounded in RTCA DO-292 [1] by assuming a completely spread PSD over the Radio-Frequency Front-end (RFFE) filter bandwidth. In this paper, the pulse collisions effects are commented, and the true post-blanker pulsed interference signal PSD is introduced through the application of the spectral separation coefficient (SSC) with the local replica PRN code signal PSD to propose a new more accurate formula for the equivalent noise level contribution of the non-blanked interference. Moreover, the C/N_0 degradation formula is derived, and its limitations are pointed out. Finally, the new proposed formula is validated through simulations for a simplified DME/TACAN signal and for DME/TACAN signals in the US hot spot.

Tau protein accumulation is a common denominator of major dementias, but this process is inhomogeneous, even when triggered by the same germline mutation. We considered stochastic misfolding of human tau conformers followed by templated conversion of native monomers as an underlying mechanism and derived sensitive conformational assays to test this concept. Assessments of brains from aged TgTauP301L transgenic mice revealed a prodromal state and three distinct signatures for misfolded tau. Frontotemporal lobar degeneration (FTLD)-MAPT-P301L patients with different clinical phenotypes also displayed three signatures, two resembling those found in TgTauP301L mice. As physicochemical and cell bioassays confirmed diverse tau strains in the mouse and human brain series, we conclude that evolution of diverse tau conformers is intrinsic to the pathogenesis of this uni-allelic form of tauopathy. In turn, effective therapeutic interventions in FTLD will need to address evolving repertoires of misfolded tau species rather than singular, static molecular targets. Electronic supplementary material The online version of this article (10.1007/s00401-020-02148-4) contains supplementary material, which is available to authorized users.

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The design of a GNSS-based integrity concept for automotive applications presents many challenges that are related to the complicated propagation channel encountered in a typical road environment. The presence of obstacles and/or reflectors on or beside the road such as large trucks, buildings, trees, walls, overpasses or tunnels can result in a large variation in the number of received signals or in the quality of the GNSS measurements and have a negative impact on the Gaussianity of the error distribution and the independence of these errors both in time and across measurements. u-blox has been working, among other solutions, on a new integrity concept referred to as Single Epoch Position Bound (SEPB) [1, 2]. It is built on: • a Bayesian estimation framework • the use of multi-frequency multi-GNSS pseudorange and carrier phase measurements • a snapshot position computation to avoid modeling time correlation • highly dynamic non-Gaussian error modeling SEPB has been shown to provide particularly tight bounds on the position. Non-Gaussian GNSS measurement error models have some major advantages in the context of high-integrity automotive positioning. For the same integrity risk, non-Gaussian error models can yield tighter position bounds than traditional Gaussian overbounding techniques, and in addition the mathematical analysis is simplified. The only major disadvantage is that the position bound evaluation can be computationally demanding, particularly if there are many unknown nuisance parameters which need to be included in the state. This is because the Bayesian framework provides the posterior distribution of the position as a function of a potentially large number of states, and evaluating bounds thus results in a computationally intensive numerical integration. To some extent, it is possible to mitigate this by computing the SEPB bound at low frequency (e.g. once every few seconds) and propagating the bound in between, but even with this optimization the computational requirements are still high. One major area for concern when using code and phase measurements in SEPB is the ionosphere. Using ionosphere-free measurements is possible but undesirable because SEPB then cannot take advantage of phase measurements. Indeed, SEPB does not fix integer phase ambiguities, but rather it integrates over the integer ambiguities when forming bounds, and hence it benefits greatly from phase measurements. There is thus a need to model the ionospheric delay. Due to spatial variations, it is difficult to safely model the ionosphere with anything other than a per-satellite parameter, which naturally leads to a large number of unknown states in the system when multiple GNSS are used. Previous published work on SEPB has side-stepped this problem by relying on short baseline RTK corrections, which made ionospheric errors negligible. However, for the non-Gaussian approach to be useful in real-world products it is essential that non-negligible ionospheric effects can be accommodated. In this paper we describe and evaluate advances in SEPB which includes per-satellite ionosphere states. We find that adding per-satellite ionosphere states does result in some increase in computational load, but that with careful design of the numerical integration scheme this load is still tractable for real-time applications. The use of bound propagation between SEPB solutions is shown to lead to an increase of the bound that remains acceptable. The bounding performance is finally evaluated based on a significant amount of real road data together with the use of a PPP correction service, to show that useful position bounds can be obtained without any atmospheric corrections. [1] Bryant, R., Julien, O., Hide, C., Moridi, S., Sheret, I., "Novel Snapshot Integrity Algorithm for Automotive Applications: Test Results Based on Real Data," 2020 IEEE/ION Position, Location and Navigation Symposium (PLANS), Portland, Oregon, April 2020, pp. 670-681. [2] Bryant, Rod, Julien, Olivier, Hide, Chris, Skorupa, M., Sheret, Ian, "Road Vehicle Integrity Bound Propagation Using GNSS/IMU/Odometer," Proceedings of the 33rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2020), September 2020, pp. 585-611.