Aberrant activation of innate immune receptors can cause a spectrum of immune disorders, such as Aicardi-Goutières syndrome (AGS). One such receptor is MDA5, a viral dsRNA sensor that induces antiviral immune response. Using a newly developed RNase-protection/RNA-seq approach, we demonstrate here that constitutive activation of MDA5 in AGS results from the loss of tolerance to cellular dsRNAs formed by Alu retroelements. While wild-type MDA5 cannot efficiently recognize Alu-dsRNAs because of its limited filament formation on imperfect duplexes, AGS variants of MDA5 display reduced sensitivity to duplex structural irregularities, assembling signaling-competent filaments on Alu-dsRNAs. Moreover, we identified an unexpected role of an RNA-rich cellular environment in suppressing aberrant MDA5 oligomerization, highlighting context dependence of self versus non-self discrimination. Overall, our work demonstrates that the increased efficiency of MDA5 in recognizing dsRNA comes at a cost of self-recognition and implicates a unique role of Alu-dsRNAs as virus-like elements that shape the primate immune system.

kinetics of ORR is around five orders of magnitude slower than that of HOR, thereby requiring a much higher Pt loading in the cathode along with more active and durable ORR electrocatalysts than pure Pt catalysts. [1] This requirement presents challenges for the development of advanced cathode catalysts with lower cost, higher activity and higher durability than Pt. Meanwhile, traditional alkaline fuel cells (AFCs) working on concentrated 30−45% KOH electrolytes gained little attention for decades mainly due to their high sensitivity to atmospheric CO 2 . [2,3] The OH − ions in the electrolyte react with CO 2 and form K 2 CO 3 , which can precipitate out as solid crystals, blocking pores in the electrode and gas diffusion layer. In addition, the consumption of OH − reduces the conductivity of the electrolyte. This issue is addressed by replacing KOH solution with a solid anion exchange membrane (AEM) without mobile cations. An AMFC offers several important advantages over PEMFCs, including: 1) low dissolution rates of catalysts, allowing the use of less expensive Pt-free electrocatalysts; 2) wide selections of materials and components that are stable at high pH; and 3) inexpensive solid electrolytes that do not need fluorinated ionomers. Despite their promise, AMFCs are still in the early development stage and have not been systematically investigated due to the lack of highly conductive and durable AEMs. The recent development of highly conductive The rapid progress of proton exchange membrane fuel cells (PEMFCs) and alkaline exchange membrane fuel cells (AMFCs) has boosted the hydrogen economy concept via diverse energy applications in the past decades. For a holistic understanding of the development status of PEMFCs and AMFCs, recent advancements in electrocatalyst design and catalyst layer optimization, along with cell performance in terms of activity and durability in PEMFCs and AMFCs, are summarized here. The activity, stability, and fuel cell performance of different types of electrocatalysts for both oxygen reduction reaction and hydrogen oxidation reaction are discussed and compared. Research directions on the further development of active, stable, and low-cost electrocatalysts to meet the ultimate commercialization of PEMFCs and AMFCs are also discussed.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202006292.

Metal halide perovskites have aroused tremendous interest in the past several years for their promising applications in display and lighting. However, the development of blue perovskite light‐emitting diodes (PeLEDs) still lags far behind that of their green and red cousins due to the difficulty in obtaining high‐quality blue perovskite emissive layers. In this study, a simple approach is conceived to improve the emission and electrical properties of blue perovskites. By introducing an alkali metal ion to occupy some sites of peripheral suspended organic ligands, the nonradiative recombination is suppressed, and, consequently, blue CsPb(Br/Cl)3 nanocrystals with a high photoluminescence quantum efficiency of 38.4% are obtained. The introduced K+ acts as a new type of metal ligand, which not only suppresses nonradiative pathways but also improves the charge carrier transport of the perovskite nanocrystals. With further engineering of the device structure to balance the charge injection rate, a spectrally stable and efficient blue PeLED with a maximum external quantum efficiency of 1.96% at the emission peak of 477 nm is fabricated.