Actions speak louder than ORFs: A non-canonical microprotein promotes medulloblastoma oncogenesis.

In this issue of Molecular Cell, Hofman et al.1 identify the translation of a non-canonical upstream open reading frame of the ASNSD1 gene into a microprotein that supports medulloblastoma growth.

Cutting edge: in the absence of regulatory T cells, a unique Th cell population expands and leads to a loss of B cell anergy.

The absence of regulatory T cells (Tregs) results in significant immune dysregulation that includes autoimmunity. The mechanism(s) by which Tregs suppress autoimmunity remains unclear. We have shown that B cell anergy, a major mechanism of B cell tolerance, is broken in the absence of Tregs. In this study, we identify a unique subpopulation of CD4(+) Th cells that are highly supportive of Ab production and promote loss of B cell anergy. Notably, this novel T cell subset was shown to express the germinal center Ag GL7 and message for the B cell survival factor BAFF, yet failed to express markers of the follicular Th cell lineage. We propose that the absence of Tregs results in the expansion of a unique nonfollicular Th subset of helper CD4(+) T cells that plays a pathogenic role in autoantibody production.

The eEF2 kinase coordinates the DNA damage response to cisplatin by supporting p53 activation.

Eukaryotic elongation factor 2 (eEF2) kinase (eEF2K) is a stress-responsive hub that inhibits the translation elongation factor eEF2, and consequently mRNA translation elongation, in response to hypoxia and nutrient deprivation. EEF2K is also involved in the response to DNA damage but its role in response to DNA crosslinks, as induced by cisplatin, is not known. Here we found that eEF2K is critical to mediate the cellular response to cisplatin. We uncovered that eEF2K deficient cells are more resistant to cisplatin treatment. Mechanistically, eEF2K deficiency blunts the activation of the DNA damage response associated ATM and ATR pathways, in turn preventing p53 activation and therefore compromising induction of cisplatin-induced apoptosis. We also report that loss of eEF2K delays the resolution of DNA damage triggered by cisplatin, suggesting that eEF2K contributes to DNA damage repair in response to cisplatin. In support of this, our data shows that eEF2K promotes the expression of the DNA repair protein ERCC1, critical for the repair of cisplatin-caused DNA damage. Finally, using Caenorhabditis elegans as an in vivo model, we find that deletion of efk-1, the worm eEF2K ortholog, mitigates the induction of germ cell death in response to cisplatin. Together, our data highlight that eEF2K represents an evolutionary conserved mediator of the DNA damage response to cisplatin which promotes p53 activation to induce cell death, or alternatively facilitates DNA repair, depending on the extent of DNA damage.

Modulation of B-cell tolerance by murine gammaherpesvirus 68 infection: requirement for Orf73 viral gene expression and follicular helper T cells.

Viruses such as Epstein-Barr virus (EBV) have been linked to mechanisms that support autoantibody production in diseases such as systemic lupus erythematosus. However, the mechanisms by which viruses contribute to autoantibody production remain poorly defined. This stems in part, from the high level of seropositivity for EBV (> 95%) and the exquisite species specificity of EBV. In this study we overcame these problems by using murine gammaherpesvirus 68 (MHV68), a virus genetically and biologically related to EBV. We first showed that MHV68 drives autoantibody production by promoting a loss of B-cell anergy. We next showed that MHV68 infection resulted in the expansion of follicular helper T (Tfh) cells in vivo, and that these Tfh cells supported autoantibody production and a loss of B-cell anergy. Finally, we showed that the expansion of Tfh cells and autoantibody production was dependent on the establishment of viral latency and expression of a functional viral gene called Orf73. Collectively, our studies highlighted an unexpected role for viral latency in the development of autoantibodies following MHV68 infection and suggest that virus-induced expansion of Tfh cells probably plays a key role in the loss of B-cell anergy.

Expansion of follicular helper T cells in the absence of Treg cells: implications for loss of B-cell anergy.

The maintenance of B-cell anergy is essential to prevent the production of autoantibodies and autoimmunity. However, B-cell extrinsic mechanisms that regulate B-cell anergy remain poorly understood. We previously demonstrated that regulatory T (Treg) cells are necessary for the maintenance of B-cell anergy. We now show that in Treg-cell-deficient mice, helper T cells are necessary and sufficient for loss of B-cell tolerance/anergy. In addition, we show that the absence of Treg cells is associated with an increase in the proportion of CD4(+) cells that express GL7 and correlated with an increase in germinal center follicular helper T (GC-T(FH) ) cells. These GC-T(FH) cells, but not those from Treg-cell-sufficient hosts, were sufficient to drive antibody production by anergic B cells. We propose that a function of Treg cells is to prevent the expansion of T(FH) cells, especially GC-T(FH) cells, which support autoantibody production.

Bidimensional SnSe2-Mesoporous Ordered Titania Heterostructures for Photocatalytically Activated Anti-Fingerprint Optically Transparent Layers.

The design of functional coatings for touchscreens and haptic interfaces is of paramount importance for smartphones, tablets, and computers. Among the functional properties, the ability to suppress or eliminate fingerprints from specific surfaces is one of the most critical. We produced photoactivated anti-fingerprint coatings by embedding 2D-SnSe2 nanoflakes in ordered mesoporous titania thin films. The SnSe2 nanostructures were produced by solvent-assisted sonication employing 1-Methyl-2-pyrrolidinone. The combination of SnSe2 and nanocrystalline anatase titania enables the formation of photoactivated heterostructures with an enhanced ability to remove fingerprints from their surface. These results were achieved through careful design of the heterostructure and controlled processing of the films by liquid phase deposition. The self-assembly process is unaffected by the addition of SnSe2, and the titania mesoporous films keep their three-dimensional pore organization. The coating layers show high optical transparency and a homogeneous distribution of SnSe2 within the matrix. An evaluation of photocatalytic activity was performed by observing the degradation of stearic acid and Rhodamine B layers deposited on the photoactive films as a function of radiation exposure time. FTIR and UV-Vis spectroscopies were used for the photodegradation tests. Additionally, infrared imaging was employed to assess the anti-fingerprinting property. The photodegradation process, following pseudo-first-order kinetics, shows a tremendous improvement over bare mesoporous titania films. Furthermore, exposure of the films to sunlight and UV light completely removes the fingerprints, opening the route to several self-cleaning applications.

Safety and Effectiveness of Concomitant Mitral Transcatheter Edge-to-Edge Repair and Left Atrial Appendage Closure.

BACKGROUND: Concomitant mitral transcatheter edge-to-edge repair (M-TEER) and left atrial appendage closure (LAAC) showed to be a feasible approach to optimize the treatment of patients eligible for both procedures, but mid-term outcomes are unclear. METHODS: We retrospectively analyzed consecutive patients undergoing M-TEER and enrolled in the local prospective Getting Reduction of Mitral Insufficiency by Percutaneous Clip Implantation (GRASP) registry. We compared patients undergoing isolated M-TEER (n = 58, 58.5%) with those undergoing concomitant M-TEER and LAAC (n = 41, 41.5%) from January 2018 to December 2022. The primary endpoint was a composite of all-cause death, stroke or systemic embolism, hospitalization for heart failure, and bleeding at 1 year. The co-primary endpoint was procedural success. RESULTS: The primary endpoint was similar between patients undergoing concomitant M-TEER+LAAC or isolated M-TEER (Kaplan Meier (KM) estimates 36.6% vs. 44.8%; plog-rank = 0.75). Procedural success was also similar (92.7% vs. 94.8%; p = 0.69). At 1- year, minor bleeds were lower in patients undergoing concomitant M-TEER and LAAC (KM estimates 0.0% vs. 18.9%; plog-rank < 0.01). CONCLUSION: In patients with concomitant MR and AF and eligible for M-TEER and LAAC treatment, a combined approach of M-TEER and LAAC was as safe as an M-TEER-alone strategy and associated with lower minor bleeding at 1 year.

Bidimensional Engineered Amorphous a-SnO2 Interfaces: Synthesis and Gas Sensing Response to H2S and Humidity.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) and metal chalcogenides (MCs), despite their excellent gas sensing properties, are subjected to spontaneous oxidation in ambient air, negatively affecting the sensor's signal reproducibility in the long run. Taking advantage of spontaneous oxidation, we synthesized fully amorphous a-SnO2 2D flakes (≈30 nm thick) by annealing in air 2D SnSe2 for two weeks at temperatures below the crystallization temperature of SnO2 (T < 280 °C). These engineered a-SnO2 interfaces, preserving all the precursor's 2D surface-to-volume features, are stable in dry/wet air up to 250 °C, with excellent baseline and sensor's signal reproducibility to H2S (400 ppb to 1.5 ppm) and humidity (10-80% relative humidity (RH)) at 100 °C for one year. Specifically, by combined density functional theory and ab initio molecular dynamics, we demonstrated that H2S and H2O compete by dissociative chemisorption over the same a-SnO2 adsorption sites, disclosing the humidity cross-response to H2S sensing. Tests confirmed that humidity decreases the baseline resistance, hampers the H2S sensor's signal (i.e., relative response (RR) = Ra/Rg), and increases the limit of detection (LOD). At 1 ppm, the H2S sensor's signal decreases from an RR of 2.4 ± 0.1 at 0% RH to 1.9 ± 0.1 at 80% RH, while the LOD increases from 210 to 380 ppb. Utilizing a suitable thermal treatment, here, we report an amorphization procedure that can be easily extended to a large variety of TMDs and MCs, opening extraordinary applications for 2D layered amorphous metal oxide gas sensors.

Incidence, Timing, Causes and Predictors of Early and Late Re-Hospitalization in Patients Who Underwent Percutaneous Mitral Valve Repair With the MitraClip System.

The pattern and reasons for re-hospitalization (RH) after MitraClip implantation are not well characterized. A total of 322 consecutive MitraClip patients were included, with data stratified by RH status. Multivariate analyses were conducted to identify predictors of early (30-day) and late (30-day to 12-month) RH. Eighty-nine patients (27.6%) were readmitted to hospital during the study period and early RH occurred in 27%. The median time from MitraClip to RH was 99 days. RH was mostly related to cardiovascular causes (66.3%). Anemia and gastrointestinal bleeding were the most frequent noncardiovascular causes. Independent predictors of early RH were length of stay ≥3 days during the index procedure (odds ratio [OR] 4.13, 95% confidence interval [CI] 1.32 to 12.91), reduction of left ventricular ejection fraction ≥5% after MitraClip implantation (OR 4.88, 95% CI 1.36 to 18.91), and severe systolic pulmonary artery pressure ≥60 mm Hg at discharge (OR 3.72, 95% CI 1.23 to 11.26). Conversely, the independent predictors of late RH were device failure (OR 4.02, 95% CI 1.22 to 13.25) and systolic pulmonary artery pressure ≥60 mm Hg at discharge (OR 2.34, 95% CI 1.01 to 5.44). In patients with early RHs, survival was significantly worse at 12 months compared with patients with late RH and no-RH (69.3% vs 82.6% vs 86%, p <0.001). In conclusion, RH is not uncommon after MitraClip implantation and cardiovascular causes represent its most frequent etiology. Clinical and echocardiographic predictors of early and late RH can be identified at discharge. Early RH carries a worse prognosis than late RH.