Genetic and functional studies strongly implicate microglia in the pathology of Alzheimer's disease. The Triggering Receptor Expressed on Myeloid cells 2 (TREM2) pathway is an important functional regulator of microglia, promoting phagocytosis of apoptotic cells, debris and pathogenic proteins. Genome-wide association studies have identified risk-bearing polymorphisms in several members of the pathway including INPP5D, encoding the inositol phosphatase SHIP1. Recent studies utilising in vitro and in vivo disease-relevant models have identified a role for SHIP1 in modulating TREM2 signalling and neurotoxic microglial activation. In this study, we characterised the role of SHIP1 in regulating TREM2 signalling and myeloid functions using human-induced pluripotent stem cell (hiPSC)-derived macrophages. Characterisation of isogenic SHIP1 knockout (SHIP1 KO) macrophages showed decreased expression of the lipopolysaccharide (LPS) coreceptor CD14, which translated to lower secretion of pro-inflammatory cytokines. Additionally, loss of SHIP1 in this macrophage model attenuated TREM2 signalling, which was further reflected in a reduced level of phagocytosis of apoptotic neurons compared to the parental line. The observed effects on TREM2 signalling did not correspond to changes in total protein levels or shedding. Further examination of macrophage scavenger receptor expression revealed reduced cell surface levels of CD163 and CD206 involved in resolution of inflammation, but increased levels of the phagocytic receptor MerTK. Morphological analysis revealed a less amoeboid-activated phenotype and increased adhesion in the SHIP1 KO macrophages. Taken together, our data indicate that SHIP1 plays a key role in modulating TREM2 signalling, inflammation and phagocytosis.
Enzymatic carbon-phosphorus bond formation is extremely rare in nature, limiting biocatalytic access to phosphorus-containing compounds that are widely used in pharmaceuticals and agrochemicals. Here, we report an asymmetric enzymatic hydrophosphorylation through oxygen activation using a repurposed flavin-dependent enzyme. Mechanistic studies revealed that reactive oxygen species are converted into productive phosphorus-centered radicals, followed by radical addition and enzymatic hydrogen atom transfer, achieving high enantioselectivity. The enzyme accommodates diverse phosphorus-hydrogen donors that pose challenges to chemical catalysis, enabling the biosynthesis of valuable phosphorus-containing scaffolds. This work expands the scope of biocatalysis to programmable carbon-phosphorus bond formation and establishes a paradigm for channeling oxygen reactivity in enzymes.
The extraordinary lifespan variation in domestic dogs provides a natural experiment for testing how intrinsic rates of biological aging shape lifespan. Using 1640 methylomes from 894 dogs, we developed an epigenetic clock that predicted mortality and demonstrated that epigenetic aging is fastest early in life. At orthologs of human age-associated genes, dogs exhibited concordant age effects on promoter methylation, highlighting conserved remodeling of immune pathways. We found that larger and male dogs, which are shorter lived, exhibit accelerated molecular aging. Distinct epigenetic architectures mediated these effects: Sex-dependent methylation changes were concentrated on the X chromosome, whereas size-associated methylation was especially pronounced at transposable elements (TEs). These findings show that epigenetics reflects lifespan differences in dogs and identifies TEs as potential mediators of size-associated lifespan.
Improvements to the radiative efficiency of halide perovskite thin films are necessary to approach fundamental solar cell performance limits. We tailored perovskite crystallization by leveraging the eutectic interaction between zinc bromide and methylammonium chloride additives. The resulting films had high photoluminescence quantum yield and charge carrier decay times and low surface recombination velocity. Nanoprobe x-ray microscopy revealed local melting of the eutectic at grain boundaries during annealing that reduced intragranular structural defect density. Annealing also homogenized the halide distribution and caused zinc segregation to grain boundaries. Solar cells fabricated with the volatile eutectic reached 26.5% power conversion efficiency (PCE, certified 25.9%), and perovskite minimodules (areas more than 15 square centimeters) had 23.9% PCE. Small-area cells with a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] hole transporter retained 85.8% of their initial 24.1% PCE after 1400 hours of continuous operation at 85 degrees C. Furthermore, this approach enables 26.1% external quantum efficiency as light-emitting diodes.
Lupins (Lupinus spp.) are promising protein crops that accumulate bitter and toxic quinolizidine alkaloids (QAs). The effective removal of QAs through new breeding technologies is hampered by a poor understanding of their biosynthesis. In this study, we used pathway reconstruction and mutant analysis to elucidate the full QA pathway in L. angustifolius [narrow-leafed lupin (NLL)] comprising 15 enzymatic steps. Major latex protein-like proteins play a prominent role in the pathway by accelerating spontaneous chemical equilibria, and an oxidoreductase-like protein ensures stereoselectivity. We also engineered a new low-alkaloid NLL line and identified the causal mutation in an existing low-alkaloid line of L. albus. Our work reveals the genetic and biochemical basis of toxic QA production and streamlines the de novo domestication of wild lupins and other QA-containing legumes.
