GalNAc-Lipid nanoparticles enable non-LDLR dependent hepatic delivery of a CRISPR base editing therapy.

Lipid nanoparticles have demonstrated utility in hepatic delivery of a range of therapeutic modalities and typically deliver their cargo via low-density lipoprotein receptor-mediated endocytosis. For patients lacking sufficient low-density lipoprotein receptor activity, such as those with homozygous familial hypercholesterolemia, an alternate strategy is needed. Here we show the use of structure-guided rational design in a series of mouse and non-human primate studies to optimize a GalNAc-Lipid nanoparticle that allows for low-density lipoprotein receptor independent delivery. In low-density lipoprotein receptor-deficient non-human primates administered a CRISPR base editing therapy targeting the ANGPTL3 gene, the introduction of an optimized GalNAc-based asialoglycoprotein receptor ligand to the nanoparticle surface increased liver editing from 5% to 61% with minimal editing in nontargeted tissues. Similar editing was noted in wild-type monkeys, with durable blood ANGPTL3 protein reduction up to 89% six months post dosing. These results suggest that GalNAc-Lipid nanoparticles may effectively deliver to both patients with intact low-density lipoprotein receptor activity as well as those afflicted by homozygous familial hypercholesterolemia.

The combination of structure and material distribution ensures functionality of the honeybee wing-coupling mechanism.

Fore- and hindwings of honeybees are coupled and synchronized to flap by means of a forewing posterior recurved margin (PRM) and hindwing hamuli which constitute a hook-furrow coupling. Morphological analysis shows that the PRM is composed of a thickened and sclerotized membrane with the Archimedean spiral configuration and hamuli are a set of tiny, sclerotized hooks with flexible bases. By developing a theoretical PRM model, the influence of cuticle sclerotization and membrane-thickening on a deforming pattern and maximal coupling force was comparatively simulated, indicating that the real PRM is capable of bearing the highest coupling force and the membrane thickening makes more contribution than cuticle sclerotization on augmenting the maximal coupling force that the PRM can resist. In addition, four combined strategies, i.e. the hook shape, Archimedean spiral, rich resilin concentration, and cuticle sclerotization in different parts of the whole system were proposed, and deemed to endow the honeybee wing-coupling with remarkable stability and durability to eliminate a potential structural failure of the coupling over millions of wing flapping cycles across the honeybee lifespan. This study assists us in the comprehensive understanding of the functionality of the hook-furrow wing-coupling and shows us new avenues for biomimetics of mobile coupling mechanisms in modern engineering.

In vivo CRISPR base editing of PCSK9 durably lowers cholesterol in primates.

Gene-editing technologies, which include the CRISPR-Cas nucleases1-3 and CRISPR base editors4,5, have the potential to permanently modify disease-causing genes in patients6. The demonstration of durable editing in target organs of nonhuman primates is a key step before in vivo administration of gene editors to patients in clinical trials. Here we demonstrate that CRISPR base editors that are delivered in vivo using lipid nanoparticles can efficiently and precisely modify disease-related genes in living cynomolgus monkeys (Macaca fascicularis). We observed a near-complete knockdown of PCSK9 in the liver after a single infusion of lipid nanoparticles, with concomitant reductions in blood levels of PCSK9 and low-density lipoprotein cholesterol of approximately 90% and about 60%, respectively; all of these changes remained stable for at least 8 months after a single-dose treatment. In addition to supporting a 'once-and-done' approach to the reduction of low-density lipoprotein cholesterol and the treatment of atherosclerotic cardiovascular disease (the leading cause of death worldwide7), our results provide a proof-of-concept for how CRISPR base editors can be productively applied to make precise single-nucleotide changes in therapeutic target genes in the liver, and potentially in other organs.

Onset of the Mach Reflection of Zel'dovich-von Neumann-Döring Detonations.

The present study investigates the similarity problem associated with the onset of the Mach reflection of Zel'dovich-von Neumann-Döring (ZND) detonations in the near field. The results reveal that the self-similarity in the frozen-limit regime is strictly valid only within a small scale, i.e., of the order of the induction length. The Mach reflection becomes non-self-similar during the transition of the Mach stem from "frozen" to "reactive" by coupling with the reaction zone. The triple-point trajectory first rises from the self-similar result due to compressive waves generated by the "hot spot", and then decays after establishment of the reactive Mach stem. It is also found, by removing the restriction, that the frozen limit can be extended to a much larger distance than expected. The obtained results elucidate the physical origin of the onset of Mach reflection with chemical reactions, which has previously been observed in both experiments and numerical simulations.

Towards Further Understanding the Secondary Fracture during Spaghetti Bent Break.

When a brittle thin rod, such as a dry spaghetti stick, is bent beyond its flexural limit, it often breaks into more than two pieces, typically three or more. This phenomenon and puzzle has aroused widespread interest and discussion since its first proposal by Feynman. Previous work has partly explained the inevitability of the secondary fracture, but without any adjustable time parameter. In order to further understand this problem, especially the secondary fracture, in this paper we propose and study the dynamics of a half-infinite model to mimic the physics that a spaghetti stick is half-infinite under uniform bending. When the breaking process starts, a gradual release of initial moment of a linearly declining time at the free end, instead of a sudden release, is adopted, resulting in the introduction of a characteristic time parameter to the model and agrees better with the real situation. A specific analytical solution in terms of the excited bending moment using Euler-Bernoulli beam theory is derived, and that the gradual release of initial moment induces a burst of flexural waves, and these flexural waves locally increase the moment in the stick and progressively get to the maximum value, and then lead to the secondary fracture are concluded. The excited moment increases with time and distance, and has an asymptotic extremum value of 1.43 times initial moment. The gradual release in our model requires and gives certain distance and time when the excited bending moment reaches its extremum value, which provides a possibility to predict the detailed fracture parameters such as fragmentation length and time and thus to further understand the secondary fracture during spaghetti bent break.

Effect of Internal Microstructure Distribution on Quasi-Static Compression Behavior and Energy Absorption of Hollow Truss Structures.

In this work, hollow truss structures with different internal microstructure distributions, i.e., basic hollow truss structure (specimen HT), hollow truss structure with internal microstructure at joints (specimen HTSJ), and hollow truss structure with internal microstructure on tube walls (specimen HTSW), were designed and manufactured using a selective laser melting technique. The effect of internal microstructure distribution on quasi-static compressive behavior and energy absorption was investigated by experimental tests and numerical simulations. The experimental results show that compressive strength and specific compressive strength of specimen HTSW increase by nearly 50% and 14% compared to specimen HT, and its energy absorption per volume and mass also increase by 52% and 15% at a strain of 0.5, respectively. However, the parameters of specimen HTSJ exhibit limited improvement or even a decrease in different degrees in comparison to specimen HT. The numerical simulation indicates that internal microstructures change the bearing capacity and structural weaknesses of the cells, resulting in the different mechanical properties and energy absorptions of the specimens. Based on the internal microstructure design in this study, adding microstructures into the internal weaknesses of the cells parallel to the loading direction is an effective way to improve the compressive properties, energy absorption and compressive stability of hollow truss structures.

Structure, properties and functions of the forewing-hindwing coupling of honeybees.

Worker honeybees (Apis mellifera) are morphologically four-winged, but are functionally dipterous insects. During flight, their fore- and hindwings are coupled by means of the forewing posterior rolled margin (PRM) and hindwing hamuli. Morphological analysis shows that the PRM can be connected to the hamuli, so that the fore- and hindwing are firmly hinged, and can rotate with respect to each other. In the present study, using a combination of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), we investigate the micromorphology and material composition of the coupling structures on both fore- and hindwings. High-speed filming is utilized to determine the angle variation between the fore- and hindwings in tethered flight. Using sets of two-dimensional (2D) computation fluid dynamic analyses, we further aim to understand the influence of the angle variation on the aerodynamic performance of the coupled wings. The results of the morphological investigations show that both PRM and hamuli are made up of a strongly sclerotized cuticle. The sclerotized hinge-like connection of the coupling structure allows a large angle variation between the wings (135°-235°), so that a change is made from an obtuse angle during the pronation and downstroke to a reflex angle during the supination and upstroke. Our computational results show that in comparison to a model with a rigid coupling hinge, the angle variation of a model having a flexible hinge results in both increased lift and drag with a higher rate of drag increase. This study deepens our understanding of the wing-coupling mechanism and functioning of coupled insect wings.

Phage-derived protein-mediated targeted chemotherapy of pancreatic cancer.

Pancreatic cancer has been a life-threatening illness associated with high incidence and mortality rates. Paclitaxel (PCT) that causes mitotic arrest in cancer cells disrupting microtubule function is used for pancreatic cancer treatment. Nausea, anorexia and abdominal pain are some of the typical dose-limiting toxicity associated gastrointestinal side effects of the drug. Here, we present the use of polymeric mixed micelles to enable a targeted delivery of PCT and to provide additional advantages such as enhanced drug solubility, bioavailability and minimal dose-limiting toxicity. Also, these micelles self-assemble with pancreatic cancer cells-specific phage proteins P38, L1 and with the hydrophobic drug PCT resolving the issue of complex chemistry efforts normally needed for any conjugation. Our cytotoxicity and binding experiment results in vitro in 2 D and 3 D models suggested that the phage protein-targeted drug-loaded micelles bind and exhibit higher cell killing over the non-targeted ones.

Investigation of span-chordwise bending anisotropy of honeybee forewings.

In this study, the spanwise and chordwise bending stiffness EI of honeybee forewings were measured by a cantilevered bending test. The test results indicate that the spanwise EI of the forewing is two orders of magnitude larger than the chordwise EI Three structural aspects result in this span-chordwise bending anisotropy: the distribution of resilin patches, the corrugation along the span and the leading edge vein of the venation. It was found that flexion lines formed by resilin patches revealed through fluorescence microscopy promoted the chordwise bending of the forewing during flapping flight. Furthermore, the corrugation of the wing and leading edge veins of the venation, revealed by micro-computed tomography, determines the relatively greater spanwise EI of the forewing. The span-chordwise anisotropy exerts positive structural and aerodynamic influences on the wing. In summary, this study potentially assists researchers in understanding the bending characteristics of insect wings and might be an important reference for the design and manufacture of bio-inspired wings for flapping micro aerial vehicles.

Combination therapy targeting both cancer stem-like cells and bulk tumor cells for improved efficacy of breast cancer treatment.

Many types of tumors are organized in a hierarchy of heterogeneous cell populations. The cancer stem-like cells (CSCs) hypothesis suggests that tumor development and metastasis are driven by a minority population of cells, which are responsible for tumor initiation, growth and recurrences. The inability to efficiently eliminate CSCs during chemotherapy, together with CSCs being highly tumorigenic and invasive, may result in treatment failure due to cancer relapse and metastases. CSCs are emerging as a promising target for the development of translational cancer therapies. Ideal panacea for cancer would kill all malignant cells, including CSCs and bulk tumor cells. Since both chemotherapy and CSCs-specific therapy are insufficient to cure cancer, we propose combination therapy with CSCs-targeted agents and chemotherapeutics for improved breast cancer treatment. We generated in vitro mammosphere of 2 breast cancer cell lines, and demonstrated ability of mammospheres to grow and enrich cancer cells with stem-like properties, including self-renewal, multilineage differentiation and enrichment of cells expressing breast cancer stem-like cell biomarkers CD44(+)/CD24(-/low). The formation of mammospheres was significantly inhibited by salinomycin, validating its pharmacological role against the cancer stem-like cells. In contrast, paclitaxel showed a minimal effect on the proliferation and growth of breast cancer stem-like cells. While combination therapies of salinomycin with conventional chemotherapy (paclitaxel or lipodox) showed a potential to improve tumor cell killing, different subtypes of breast cancer cells showed different patterns in response to the combination therapies. While optimization of combination therapy is warranted, the design of combination therapy should consider phenotypic attributes of breast cancer types.

[T cell immunity analysis in children with obstructive sleep apnea syndrome].

OBJECTIVE: To probe into the possible impact on T cell immunity in children with obstructive sleep apnea syndrome (OSAS). METHOD: Lymphocytes in peripheral blood vessel of children with OSAS vs normal controls were checked by APAAP method and analyzed statistically. RESULT: The comparison with the controls showed that CD3+ had no significant difference (P>0.05), CD4+, CD4+/CD8+ were significantly lower, CD8+ was significantly higher in children with OSAS (P<0.01), and the analysis of the LSaO2 and period of history showed that the lower the LSaO2, and the longer the period of history, the more effect to CD4+, CD8+, CD3+/CD8+ (P<0.05). CONCLUSION: T cell immunity are impaired in children with OSAS.