Highly transparent cellulose-based phosphorescent materials with tunable afterglow colors and white emission.

Room temperature phosphorescence (RTP) materials with wood as framework are highly desirable due to their extended afterglow, high haze and good mechanical properties, which is highly desired in lighting materials. However, it remains challenging to obtain wood-based RTP materials that possess on-demand afterglow colors while maintaining high transparency across the entire visible spectrum. In this study, long-persistent phosphorescent transparent composite with tunable afterglow color is fabricated by infiltrating delignified wood with phosphors (including carbazole, naphthalene, and pyrene) doped polymethyl methacrylate (PMMA). Such RTP woods indicate remarkable transparency, over 70 %, and an extended afterglow duration of up to 8 s. Here, PMMA serves as rigid surrounding to suppress the non-radiative transition of phosphors to ensure phosphorescence, and to fulfill in the wood lumen to match the refractive index of cellulose for transparency. By formulating phosphors with different types and concentration ratios, transparent woods with diverse phosphorescence colors, and white emission, are successfully achieved. Furthermore, the RTP woods demonstrate dynamically tunable afterglow colors over time based on the varied phosphorescent lifetimes. Characterized by their high transparency and tunable colors, these natural wood-based RTP materials have great potentials for application in the fields of LED materials, optics, and building materials.

Functional mouse hepatocytes derived from interspecies chimeric livers effectively mitigate chronic liver fibrosis.

Liver disease is a major global health challenge. There is a shortage of liver donors worldwide, and hepatocyte transplantation (HT) may be an effective treatment to overcome this problem. However, the present approaches for generation of hepatocytes are associated with challenges, and interspecies chimera-derived hepatocytes produced by interspecies blastocyst complementation (IBC) may be promising donor hepatocytes because of their more comprehensive hepatic functions. In this study, we isolated mouse hepatocytes from mouse-rat chimeric livers using IBC and found that interspecies chimera-derived hepatocytes exhibited mature hepatic functions in terms of lipid accumulation, glycogen storage, and urea synthesis. Meanwhile, they were more similar to endogenous hepatocytes than hepatocytes derived in vitro. Interspecies chimera-derived hepatocytes could relieve chronic liver fibrosis and reside in the injured liver after transplantation. Our results suggest that interspecies chimera-derived hepatocytes are a potentially reliable source of hepatocytes and can be applied as a therapeutic approach for HT.

Therapeutic In Vivo Gene Editing Achieved by a Hypercompact CRISPR-Cas12f1 System Delivered with All-in-One Adeno-Associated Virus.

CRISPR-based gene therapies are making remarkable strides toward the clinic. But the large size of most widely used Cas endonucleases including Cas9 and Cas12a restricts their efficient delivery by the adeno-associated virus (AAV) for in vivo gene editing. Being exceptionally small, the recently engineered type V-F CRISPR-Cas12f1 systems can overcome the cargo packaging bottleneck and present as strong candidates for therapeutic applications. In this study, the pairwise editing efficiencies of different engineered Cas12f1/sgRNA scaffold combinations are systemically screened and optimized, and the CasMINI_v3.1/ge4.1 system is identified as being able to significantly boost the gene editing activity. Moreover, packaged into single AAV vectors and delivered via subretinal injection, CasMINI_v3.1/ge4.1 achieves remarkably high in vivo editing efficiencies, over 70% in transduced retinal cells. Further, the efficacy of this Cas12f1 system-based gene therapy to treat retinitis pigmentosa in RhoP23H mice is demonstrated by the therapeutic benefits achieved including rescued visual function and structural preservation. And minimal bystander editing activity is detected. This work advances and expands the therapeutic potential of the miniature Cas12f1 system to support efficient and accurate in vivo gene therapy.

Knockout and Replacement Gene Surgery to Treat Rhodopsin-Mediated Autosomal Dominant Retinitis Pigmentosa.

Mutations in the rhodopsin (RHO) gene are the predominant causes of autosomal dominant retinitis pigmentosa (adRP). Given the diverse gain-of-function mutations, therapeutic strategies targeting specific sequences face significant challenges. Here, we provide a universal approach to conquer this problem: we have devised a CRISPR-Cas12i-based, mutation-independent gene knockout and replacement compound therapy carried by a dual AAV2/8 system. In this study, we successfully delayed the progression of retinal degeneration in the classic mouse disease model RhoP23H, and also RhoP347S, a new native mouse mutation model we developed. Our research expands the horizon of potential options for future treatments of RHO-mediated adRP.

Programmable synthetic receptors: the next-generation of cell and gene therapies.

Cell and gene therapies hold tremendous promise for treating a range of difficult-to-treat diseases. However, concerns over the safety and efficacy require to be further addressed in order to realize their full potential. Synthetic receptors, a synthetic biology tool that can precisely control the function of therapeutic cells and genetic modules, have been rapidly developed and applied as a powerful solution. Delicately designed and engineered, they can be applied to finetune the therapeutic activities, i.e., to regulate production of dosed, bioactive payloads by sensing and processing user-defined signals or biomarkers. This review provides an overview of diverse synthetic receptor systems being used to reprogram therapeutic cells and their wide applications in biomedical research. With a special focus on four synthetic receptor systems at the forefront, including chimeric antigen receptors (CARs) and synthetic Notch (synNotch) receptors, we address the generalized strategies to design, construct and improve synthetic receptors. Meanwhile, we also highlight the expanding landscape of therapeutic applications of the synthetic receptor systems as well as current challenges in their clinical translation.

Gamma distribution based predicting model for breast cancer drug response based on multi-layer feature selection.

In the pursuit of precision medicine for cancer, a promising step is to predict drug response based on data mining, which can provide clinical decision support for cancer patients. Although some machine learning methods for predicting drug response from genomic data already exist, most of them focus on point prediction, which cannot reveal the distribution of predicted results. In this paper, we propose a three-layer feature selection combined with a gamma distribution based GLM and a two-layer feature selection combined with an ANN. The two regression methods are applied to the Encyclopedia of Cancer Cell Lines (CCLE) and the Cancer Drug Sensitivity Genomics (GDSC) datasets. Using ten-fold cross-validation, our methods achieve higher accuracy on anticancer drug response prediction compared to existing methods, with an R 2 and RMSE of 0.87 and 0.53, respectively. Through data validation, the significance of assessing the reliability of predictions by predicting confidence intervals and its role in personalized medicine are illustrated. The correlation analysis of the genes selected from the three layers of features also shows the effectiveness of our proposed methods.

Engineered Wood with Hierarchically Tunable Microchannels toward Efficient Solar Vapor Generation.

Wood-based solar steam evaporators have been attracting increasing interest due to their great potential for addressing water scarcity by utilizing sustainable materials and energy. However, engineering a 3D porous structure within the wood lumens and its effect on solar vapor evaporation have not yet been well explored. Here, a natural wood-based solar evaporator with hierarchical pores is fabricated by assembling polyvinyl alcohol within the lumens through an ice-templating approach. The polyvinyl alcohol porous network is engineered from vertically aligned microchannels to dendritically bridged pores with a narrowed size of a few micrometers and significantly increased surface area. Although the formation of plenty of microscopic channels increases the capillary force in comparison to the native wood lumen, the morphology change induces a high tortuosity factor of the porous structure, resulting in a reduced water transportation rate as well as an increased contact angle. On the other hand, the high surface area of the engineered wood lumens and the good hydrophilicity of the filled polyvinyl alcohol improve the ratio of the formed intermediate water, contributing to reduced vaporization enthalpy. Consequently, by using polydopamine as the photothermal material, the hierarchically structured polyvinyl alcohol-wood solar evaporator exhibits an evaporation rate of 1.6 kg m-2 h-1 under 1 sun irradiation and a high solar evaporation efficiency of up to 107%, which are higher than most of the reported natural-wood-based solar evaporators. Moreover, by exploring the correlation between porous morphology and performance, it has been found that the polyvinyl alcohol-wood composite not only presents an inexpensive and sustainable evaporator but also provides guidelines for designing high-performance steam generation devices.

Continuous expression of reprogramming factors induces and maintains mouse pluripotency without specific growth factors and signaling inhibitors.

OBJECTIVES: Derivation and maintenance of pluripotent stem cells (PSCs) generally require optimized and complex culture media, which hinders the derivation of PSCs from various species. Expression of Oct4, Sox2, Klf4, and c-Myc (OSKM) can reprogram somatic cells into induced PSCs (iPSCs), even for species possessing no optimal culture condition. Herein, we explored whether expression of OSKM could induce and maintain pluripotency without PSC-specific growth factors and signaling inhibitors. METHODS: The culture medium of Tet-On-OSKM/Oct4-GFP mouse embryonic stem cells (ESCs) was switched from N2B27 with MEK inhibitor, GSK3ß inhibitor, and leukemia inhibitory factor (LIF) (2iL) to N2B27 with doxycycline. Tet-On-OSKM mouse embryonic fibroblast (MEF) cells were reprogrammed in N2B27 with doxycycline. Cell proliferation was traced. Pluripotency was assessed by expression of ESC marker genes, teratoma, and chimera formation. RNA-Seq was conducted to analyze gene expression. RESULTS: Via continuous expression of OSKM, mouse ESCs (OSKM-ESCs) and the resulting iPSCs (OSKM-iPSCs) reprogrammed from MEF cells propagated stably, expressed pluripotency marker genes, and formed three germ layers in teratomas. Transcriptional landscapes of OSKM-iPSCs resembled those of ESCs cultured in 2iL and were more similar to those of ESCs cultured in serum/LIF. Furthermore, OSKM-iPSCs contributed to germline transmission. CONCLUSIONS: Expression of OSKM could induce and maintain mouse pluripotency without specific culturing factors. Importantly, OSKM-iPSCs could produce gene-modified animals through germline transmission, with potential applications in other species.

Reconstruction of functional uterine tissues through recellularizing the decellularized rat uterine scaffolds by MSCs in vivo and in vitro.

Infertile people who suffered from loss of uterine structures and/or functions can be treated through gestational surrogacy or uterus transplantation, which remains challenging due to the ethical and social issues, the lack of donor organs as well as technical and safety risks. One promising solution is to regenerate and reconstruct a bioartificial uterus for transplantation through the engineering of uterine architecture and appropriate cellular constituents. Here, we developed a well-defined system to regenerate a functional rat uterine through recellularization of the decellularized uterine matrix (DUM) patches reseeded with human mesenchymal stem cells (hMSCs). Engraftment of the recellularized DUMs on the partially excised uteri yielded a functional rat uterus with a pregnancy rate and number of fetuses per uterine horn comparable to that of the control group with an intact uterus. Particularly, the recellularized DUMs enhanced the regeneration of traumatic uterine in vivo because of MSC regulation. The established system here will shed light on the treatment of uterine infertility with heterogeneous DUMs/cell resources through tissue engineering in the future.

Modeling human embryo development with embryonic and extra-embryonic stem cells.

Early human post-implantation development involves extensive growth combined with a series of complex morphogenetic events. The lack of precise spatial and temporal control over these processes leads to pregnancy loss. Given the ethical and technical limitations in studying the natural human embryo, alternative approaches are needed to investigate mechanisms underlying this critical stage of human development. Here, we present an overview of the different stem cells and stem cell-derived models which serve as useful, albeit imperfect, tools in understanding human embryogenesis. Current models include stem cells that represent each of the three earliest lineages: human embryonic stem cells corresponding to the epiblast, hypoblast-like stem cells and trophoblast stem cells. We also review the use of human embryonic stem cells to model complex aspects of epiblast morphogenesis and differentiation. Additionally, we propose that the combination of both embryonic and extra-embryonic stem cells to form three-dimensional embryo models will provide valuable insights into cell-cell chemical and mechanical interactions that are essential for natural embryogenesis.

Current advances in haploid stem cells.

Diploidy is the typical genomic mode in all mammals. Haploid stem cells are artificial cell lines experimentally derived in vitro in the form of different types of stem cells, which combine the characteristics of haploidy with a broad developmental potential and open the possibility to uncover biological mysteries at a genomic scale. To date, a multitude of haploid stem cell types from mouse, rat, monkey and humans have been derived, as more are in development. They have been applied in high-throughput genetic screens and mammalian assisted reproduction. Here, we review the generation, unique properties and broad applications of these remarkable cells.

CDetection: CRISPR-Cas12b-based DNA detection with sub-attomolar sensitivity and single-base specificity.

CRISPR-based nucleic acid detection methods are reported to facilitate rapid and sensitive DNA detection. However, precise DNA detection at the single-base resolution and its wide applications including high-fidelity SNP genotyping remain to be explored. Here we develop a Cas12b-mediated DNA detection (CDetection) strategy, which shows higher sensitivity on examined targets compared with the previously reported Cas12a-based detection platform. Moreover, we show that CDetection can distinguish differences at the single-base level upon combining the optimized tuned guide RNA (tgRNA). Therefore, our findings highlight the high sensitivity and accuracy of CDetection, which provides an efficient and highly practical platform for DNA detection.

Enhanced mammalian genome editing by new Cas12a orthologs with optimized crRNA scaffolds.

CRISPR-Cas12a/Cpf1, a single RNA-guided endonuclease system, provides a promising tool for genome engineering. However, only three Cas12a orthologs have been employed for mammalian genome editing, and the editing efficiency as well as targeting coverage still requires improvements. Here, we harness six novel Cas12a orthologs for genome editing in human and mouse cells, some of which utilize simple protospacer adjacent motifs (PAMs) that remarkably increase the targeting range in the genomes. Moreover, we identify optimized CRISPR RNA (crRNA) scaffolds that can increase the genome editing efficiency of Cas12a.

Derivation of Mouse Haploid Trophoblast Stem Cells.

Trophoblast stem (TS) cells are increasingly used as a model system for studying placentation and placental disorders. However, practical limitations of genetic manipulation have posed challenges for genetic analysis using TS cells. Here, we report the generation of mouse parthenogenetic haploid TS cells (haTSCs) and show that supplementation with FGF4 and inhibition of Rho-associated protein kinase (ROCK) enable the maintenance of their haploidy and developmental potential. The resulting haTSCs have 20 chromosomes, exhibit typical expression features of TS cells, possess the multipotency to differentiate into specialized trophoblast cell types, and can chimerize E13.5 and term placentas. We also demonstrate the capability of the haTSCs to undergo genetic manipulation and facilitate genome-wide screening in the trophoblast lineage. We expect that haTSCs will offer a powerful tool for studying functional genomics and placental biology.

Repurposing CRISPR-Cas12b for mammalian genome engineering.

The prokaryotic CRISPR-Cas adaptive immune systems provide valuable resources to develop genome editing tools, such as CRISPR-Cas9 and CRISPR-Cas12a/Cpf1. Recently, CRISPR-Cas12b/C2c1, a distinct type V-B system, has been characterized as a dual-RNA-guided DNA endonuclease system. Though being active in vitro, its cleavage activity at endogenous genome remains to be explored. Furthermore, the optimal cleavage temperature of the reported Cas12b orthologs is higher than 40 °C, which is unsuitable for mammalian applications. Here, we report the identification of a Cas12b system from the Alicyclobacillus acidiphilus (AaCas12b), which maintains optimal nuclease activity over a wide temperature range (31 °C-59 °C). AaCas12b can be repurposed to engineer mammalian genomes for versatile applications, including single and multiplex genome editing, gene activation, and generation of gene mutant mouse models. Moreover, whole-genome sequencing reveals high specificity and minimal off-target effects of AaCas12b-meditated genome editing. Our findings establish CRISPR-Cas12b as a versatile tool for mammalian genome engineering.

Rat embryonic stem cells produce fertile offspring through tetraploid complementation.

Pluripotency of embryonic stem cells (ESCs) can be functionally assessed according to the developmental potency. Tetraploid complementation, through which an entire organism is produced from the pluripotent donor cells, is taken as the most stringent test for pluripotency. It remains unclear whether ESCs of other species besides mice can pass this test. Here we show that the rat ESCs derived under 2i (two small molecule inhibitors) conditions at very early passages are able to produce fertile offspring by tetraploid complementation. However, they lose this capacity rapidly during culture due to a nearly complete loss of genomic imprinting. Our findings support that the naïve ground state pluripotency can be captured in rat ESCs but also point to the species-specific differences in its regulation and maintenance, which have implications for the derivation and application of naïve pluripotent stem cells in other species including human.