Accelerating the Discovery of Hybrid Perovskites with Targeted Band Gaps via Interpretable Machine Learning.

The band gap of hybrid organic-inorganic perovskites (HOIPs) is a key factor affecting the light absorption characteristics and thus the performance of perovskite solar cells (PSCs). However, band gap engineering, using experimental trial and error and high-throughput density functional theory calculations, is blind and costly. Therefore, it is critical to statistically identify the multiple factors influencing band gaps and to rationally design perovskites with targeted band gaps. This study combined feature engineering, the gradient-boosted regression tree (GBRT) algorithm, and the genetic algorithm-based symbolic regression (GASR) algorithm to develop an interpretable machine learning (ML) strategy for predicting the band gap of HOIPs accurately and quantitatively interpreting the factors affecting the band gap. Seven best physical features were selected to construct a GBRT model with a root-mean-square error of less than 0.060 eV, and the most important feature is the electronegativity difference between the B-site and the X-site (χB-X). Further, a mathematical formula (Eg = χB-X2 + 0.881χB-X) was constructed with GASR for a quantitative interpretation of the band gap influence patterns. According to the ML model, the HOIP MA0.23FA0.02Cs0.75Pb0.59Sn0.41Br0.24I2.76 was obtained, with a suitable band gap of 1.39 eV. Our proposed interpretable ML strategy provides an effective approach for developing HOIP structures with targeted band gaps, which can also be applied to other material fields.

Enhancing Drug Utilization Efficiency via Dish-Structured Triboelectric Nanogenerator.

Due to the finding of severe side effects and low therapeutic efficacy with cancer chemotherapy, there still remains a great challenge to benefit patients with curative effect. In this work, we designed a self-powered drug delivery system comprising a current source derived from the disk TENG (D-TENG) and a pair of Au electrodes. Thus, cells seeded within the electrode gap could be stimulated by the current followed by D-TENG`s work. Under the rotation frequency of about 7.4 Hz, the peak output current and voltage of the D-TENG reached 3.7 µA and 135 V and achieved an average of 2.8 µA of output current. Furthermore, the D-TENG also showed its good stability to output steady current in a long-term condition. When applying the electric stimulation by this self-powered drug delivery system, a chemotherapy drug, doxorubicin (DOX), had significant uptake by cancer cells. Therefore, utilizing a novel TENG device as a part of chemotherapy would provide a new opportunity in future disease treatment.

Bruceae Fructus Oil Inhibits Triple-Negative Breast Cancer by Restraining Autophagy: Dependence on the Gut Microbiota-Mediated Amino Acid Regulation.

Triple-negative breast cancer (TNBC) has been acknowledged as an aggressive disease with worst prognosis, which requires endeavor to develop novel therapeutic agents. Bruceae fructus oil (BO), a vegetable oil derived from the fruit of Brucea javanica (L.) Merr., is an approved marketable drug for the treatment of cancer in China for several decades. Despite that the anti-breast cancer activity of several quassinoids derived from B. javanica has been found, it was the first time that the potential of BO against TNBC was revealed. Although BO had no cytotoxicity on TNBC cell lines in vitro, the oral administration of BO exhibited a gut microbiota-dependent tumor suppression without toxicity on the non-targeted organs in vivo. By metagenomics and untargeted metabolomics, it was found that BO not only altered the composition and amino acid metabolism function of gut microbiota but also regulated the host's amino acid profile, which was in accordance with the metabolism alternation in gut microbiota. Moreover, the activity of mTOR in tumor was promoted by BO treatment as indicated by the phosphorylation of 4E-binding protein 1 (4E-BP1) and ribosomal protein S6, and hyper-autophagy was consequently restrained. By contrast, the failure of tumor suppression by BO under pseudo germ-free (PGF) condition came with indistinctive changes in autophagy and mTOR activity, implying the critical role of the gut microbiota in BO's anticancer activity. The present study highlighted a promising application of BO against breast cancer with novel efficacy and safety.

Anti-glioblastoma Activity of Kaempferol via Programmed Cell Death Induction: Involvement of Autophagy and Pyroptosis.

Glioblastoma is one of the most common and lethal intracranial malignant, and is still lack of ideal treatments. Kaempferol is a major nutrient found in various edible plants, which has exhibited the potential for the treatment of glioblastoma. However, the specific anti-glioma mechanism of kaempferol is yet to be studied. Herein, we aim to explore the mechanisms underlying the anti-glioma activity of kaempferol. Our results demonstrated that kaempferol suppresses glioma cell proliferation in vitro and inhibits tumor growth in vivo. Moreover, kaempferol raises ROS and decreases mitochondrial membrane potential in glioma cells. The high levels of ROS induce autophagy then ultimately trigger the pyroptosis of glioma cells. Interestingly, when we used 3-MA to inhibit autophagy, we found that the cleaved form of GSDME was also decreased, suggesting that kaempferol induces pyroptosis through regulating autophagy in glioma cells. In conclusion, this study revealed kaempferol possesses good anti-glioma activity by inducing ROS, and subsequently leads to autophagy and pyroptosis, highlighting its clinical potentials as a natural nutrient against glioblastoma.

hESC-derived immune suppressive dendritic cells induce immune tolerance of parental hESC-derived allografts.

BACKGROUND: With their inherent capability of unlimited self-renewal and unique potential to differentiate into functional cells of the three germ layers, human embryonic stem cells (hESCs) hold great potential in regenerative medicine. A major challenge in the application of hESC-based cell therapy is the allogeneic immune rejection of hESC-derived allografts. METHODS: We derived dendritic cell-like cells (DCLs) from wild type and CTLA4-Ig/PD-L1 knock-in hESCs, denoted WT DCLs and CP DCLs. The expression of DC-related genes and surface molecules was evaluated, as well as their DCL capacity to stimulate allogeneic T cells and induce regulatory T (Treg) cells in vitro. Using an immune system humanized mouse model, we investigated whether the adoptive transfer of CP DCLs can induce long-term immune tolerance of parental hESC-derived smooth muscle and cardiomyocyte allografts. FINDINGS: CP DCLs can maintain immune suppressive properties after robust inflammatory stimulation and induce Treg cells. While CP DCLs survive transiently in vivo, they induce long-term immune tolerance of parental hESC-derived allografts. INTERPRETATION: This strategy does not cause systemic immune suppression but induces immune tolerance specific for DCL-specific HLAs, and thus it presents a safe and effective approach to induce immune tolerance of allografts derived from any clinically approved hESC line. FUNDING: NSFC, leading talents of Guangdong Province Program (No. 00201516), Key R&D Program of Guangdong Province (2019B020235003), Science and Technology Innovation Committee of Shenzhen Municipality (JCYJ20180504170301309), National High-tech R&D Program (863 Program No. 2015AA020310), Shenzhen "Sanming" Project of Medicine (SZSM201602102), Development and Reform Commission of Shenzhen Municipality (S2016004730009), CIRM (DISC2-10559).

Rapid 3D bioprinting of in vitro cardiac tissue models using human embryonic stem cell-derived cardiomyocytes.

There is a great need for physiologically relevant 3D human cardiac scaffolds for both short-term, the development of drug testing platforms to screen new drugs across different genetic backgrounds, and longer term, the replacement of damaged or non-functional cardiac tissue after injury or infarction. In this study, we have designed and printed a variety of scaffolds for in vitro diagnostics using light based Micro-Continuous Optical Printing (µCOP). Human embryonic stem cell-derived cardiomyocyte (hESC-CMs) were directly printed into gelatin hydrogel on glass to determine their viability and ability to align. The incorporation of Green Fluorescent Protein/Calmodulin/M13 Peptide (GCaMP3)-hESC-CMs allowed the ability to continuously monitor calcium transients over time. Normalized fluorescence of GCaMP3-hESCCMs increased by 18 ± 6% and 40 ± 5% when treated with 500 nM and 1 µM of isoproterenol, respectively. Finally, GCaMP3-hESC-CMs were printed across a customizable 3D printed cantilever-based force system. Along with force tracking by visualizing the displacement of the cantilever, calcium transients could be observed in a non-destructive manner, allowing the samples to be examined over several days. Our µCOP-printed cardiac models presented here can be used as a powerful tool for drug screening and to analyze cardiac tissue maturation.

IDO1 Maintains Pluripotency of Primed Human Embryonic Stem Cells by Promoting Glycolysis.

Human embryonic stem cells (hESCs) depend on glycolysis for energy supply and pluripotency and switch to oxidative phosphorylation upon differentiation. The underlying mechanisms remain unclear. Here, we demonstrate that indoleamine 2,3-dioxygenase 1 (IDO1) is expressed in primed hESCs and its expression rapidly downregulated upon hESC differentiation. IDO1 is required to maintain pluripotency by suppressing mitochondria activity and promoting glycolysis through the increase of NAD+ /NADH ratio. The upregulation of IDO1 during hESC differentiation suppresses the differentiation of hESCs into certain lineages of cells such as cardiomyocytes, which depend on oxidative phosphorylation to satisfy their high energy demand. Therefore, IDO1 plays important roles in maintaining the pluripotency of hESCs. Stem Cells 2019;37:1158-1165.

Wild-Type p53 Promotes Cancer Metabolic Switch by Inducing PUMA-Dependent Suppression of Oxidative Phosphorylation.

The tumor suppressor p53 is somatically mutated in half of all human cancers. Paradoxically, the wild-type p53 (WTp53) is often retained in certain human cancers, such as hepatocarcinoma (HCC). We discovered a physiological and oncogenic role of WTp53 in suppressing pyruvate-driven oxidative phosphorylation by inducing PUMA. PUMA inhibits mitochondrial pyruvate uptake by disrupting the oligomerization and function of mitochondrial pyruvate carrier (MPC) through PUMA-MPC interaction, which depends on IκB kinase-mediated phosphorylation of PUMA at Ser96/106. High expression levels of PUMA are correlated with decreased mitochondrial pyruvate uptake and increased glycolysis in HCCs and poor prognosis of HCC patients. These findings are instrumental for cancer drug discovery aiming at activating WTp53 or restoring WTp53 activity to p53 mutants.

An Immune System-Modified Rat Model for Human Stem Cell Transplantation Research.

Due to its lack of both innate and acquired immune responses to human cells, the NODSCIDIl2rγ-/- (NSG) mouse model has become an important tool for human stem cell research. When compared with the mouse, the rat is physiologically more similar to humans and offers advantages in preclinical efficacy studies on human stem cells, particularly in evaluating neural, hepatic, and cardiac functions. Therefore, we generated a human SIRPα+Prdkc-/-Il2rγ-/- rat model, denoted NSG-like (NSGL) rat, which expresses human SIRPα and is abolished in the development of B, T, and natural killer cells. When compared with Prdkc-/-Il2rγ-/- (SG) rats, NSGL rats allow more efficient engraftment of human cancer cells and human pluripotent stem cells. In addition, only NSGL rats, but not SG rats, can be engrafted with human hematopoietic stem cells to reconstitute the human immune system. Therefore, NSGL rats represent an improved xenotransplantation model for efficacy studies of human stem cells.

T cell inhibition by pogostone from Pogostemon cablin (Blanco) Benth: In vitro and in vivo immunosuppressive analysis.

Various plant-derived compounds exhibit immunosuppressive activity in pre­clinical investigations, suggesting that they may serve as natural alternatives for the prevention of inflammatory disorders and autoimmune diseases. The aim of the current study was to explore the immunosuppressive potential of pogostone (PO) derived from Pogostemon cablin (Blanco) Benth. Carboxyfluorescein diacetate succinimidyl ester­labeled cell tracking demonstrated that PO (20­80 µM) inhibited Concanavalin A (ConA)­stimulated lymphocyte proliferation, which was mediated by G0/G1 phase arrest and accompanied by significant decreases in the expression of CD69 (early­stage activation marker) and CD25 (mid­stage activation marker) in T cells, as indicated by flow cytometry analysis. Furthermore, the proliferation blocking ability of PO (5­80 µM) was not associated with cytotoxicity in normal lymphocytes or apoptosis in ConA­stimulated lymphocytes. The inflammatory cytokine profile determination using a cytometric beads assay revealed that PO inhibited release of anti­inflammatory interleukin (IL)­10 and pro­inflammatory IL­6 from the stimulated lymphocytes. Furthermore, PO (10, 20 or 40 mg/kg) ameliorated the T­cell mediated delayed type hypersensitivity response in Balb/c mice by reducing leukocyte infiltration and tissue edema, providing a further validation of the direct immunosuppressive activity of PO. Together, the present data suggest that PO would suppress T cell response via a direct non­cytotoxic inactivation at the early stage, accompanied by regulation of the inflammatory cytokine profile, which highlights clinical implications for treatment of immune-based disorders.

Humanized mouse model for assessing the human immune response to xenogeneic and allogeneic decellularized biomaterials.

Current assessment of biomaterial biocompatibility is typically implemented in wild type rodent models. Unfortunately, different characteristics of the immune systems in rodents versus humans limit the capability of these models to mimic the human immune response to naturally derived biomaterials. Here we investigated the utility of humanized mice as an improved model for testing naturally derived biomaterials. Two injectable hydrogels derived from decellularized porcine or human cadaveric myocardium were compared. Three days and one week after subcutaneous injection, the hydrogels were analyzed for early and mid-phase immune responses, respectively. Immune cells in the humanized mouse model, particularly T-helper cells, responded distinctly between the xenogeneic and allogeneic biomaterials. The allogeneic extracellular matrix derived hydrogels elicited significantly reduced total, human specific, and CD4+ T-helper cell infiltration in humanized mice compared to xenogeneic extracellular matrix hydrogels, which was not recapitulated in wild type mice. T-helper cells, in response to the allogeneic hydrogel material, were also less polarized towards a pro-remodeling Th2 phenotype compared to xenogeneic extracellular matrix hydrogels in humanized mice. In both models, both biomaterials induced the infiltration of macrophages polarized towards a M2 phenotype and T-helper cells polarized towards a Th2 phenotype. In conclusion, these studies showed the importance of testing naturally derived biomaterials in immune competent animals and the potential of utilizing this humanized mouse model for further studying human immune cell responses to biomaterials in an in vivo environment.

A Safety Checkpoint to Eliminate Cancer Risk of the Immune Evasive Cells Derived from Human Embryonic Stem Cells.

Human embryonic stem cells (hESCs) hold great promise in the regenerative therapy of many currently untreatable human diseases. One of the key bottlenecks is the immune rejection of hESC-derived allografts by the recipient. To overcome this challenge, we have established new approaches to induce immune protection of hESC-derived allografts through the coexpression of immune suppressive molecules CTLA4-Ig and PD-L1. However, this in turn raises a safety concern of cancer risk because these hESC-derived cells can evade immune surveillance. To address this safety concern, we developed a safety checkpoint so that the immune evasive hESC-derived cells in the graft can be effectively eliminated if any cellular transformation is detected. In this context, we knock-in the suicidal gene herpes simplex virus thymidine kinase (HSVTK) into the constitutive HPRT locus of CP hESCs (knock-in hESCs expressing CTLA4-Ig and PD-L1), denoted CPTK hESCs. Employing humanized mice (Hu-mice) reconstituted with human immune system, we demonstrated that the CPTK hESC-derived cells are protected from immune rejection. In addition, CPTK hESC-derived cells can be efficiently eliminated in vitro and in vivo with FDA approved TK-targeting drug ganciclovir. Therefore, this new safety checkpoint improves the feasibility to use the immune evasive hESC-derived cells for regenerative medicine. Stem Cells 2017;35:1154-1161.

Brief Report: Immune Microenvironment Determines the Immunogenicity of Induced Pluripotent Stem Cell Derivatives.

The breakthrough of induced pluripotent stem cells (iPSCs) has raised the possibility that patient-specific iPSCs can provide autologous cells for cell therapy without the concern for immune rejection. However, the immunogenicity of iPSC-derived cells remains controversial. Using syngeneic C57BL/6 (B6) mouse transplantation model, several studies indicate that B6 iPSC-derived cells exhibit some levels of immunogenicity when transplanted into B6 mice subcutaneously. In contrast, one recent study has concluded that various lineages of B6 iPSC-derived cells exhibit no immunogenicity when transplanted under the kidney capsule of B6 mice. To resolve the controversy concerning this critical issue of iPSC biology, we used the same B6 transplantation model to demonstrate that the immune response toward antigens is dependent on the immune environment of the transplantation site. Immunogenic antigen-expressing B6 embryonic stem cells (ESCs) as well as B6 iPSCs and their terminally differentiated cells survived under the kidney capsule but are immune rejected when transplanted subcutaneously or intramuscularly. The cotransplantation of mature B6 dendritic cells under the kidney capsule leads to immune rejection of B6 iPSC-derived grafts but not B6 ESC-derived grafts, indicating that the lack of detectable immune response to iPSC-derived grafts under the kidney capsule is due to the lack of functional antigen presenting cells.

Humanized Mice Reveal Differential Immunogenicity of Cells Derived from Autologous Induced Pluripotent Stem Cells.

The breakthrough of induced pluripotent stem cell (iPSC) technology has raised the possibility that patient-specific iPSCs may become a renewable source of autologous cells for cell therapy without the concern of immune rejection. However, the immunogenicity of autologous human iPSC (hiPSC)-derived cells is not well understood. Using a humanized mouse model (denoted Hu-mice) reconstituted with a functional human immune system, we demonstrate that most teratomas formed by autologous integration-free hiPSCs exhibit local infiltration of antigen-specific T cells and associated tissue necrosis, indicating immune rejection of certain hiPSC-derived cells. In this context, autologous hiPSC-derived smooth muscle cells (SMCs) appear to be highly immunogenic, while autologous hiPSC-derived retinal pigment epithelial (RPE) cells are immune tolerated even in non-ocular locations. This differential immunogenicity is due in part to abnormal expression of immunogenic antigens in hiPSC-derived SMCs, but not in hiPSC-derived RPEs. These findings support the feasibility of developing hiPSC-derived RPEs for treating macular degeneration.

Kinetics and mechanism study of competitive inhibition of jack-bean urease by baicalin.

Baicalin (BA) is the principal component of Radix Scutellariae responsible for its pharmacological activity. In this study, kinetics and mechanism of inhibition by BA against jack-bean urease were investigated for its therapeutic potential. It was revealed that the IC50 of BA against jack-bean urease was 2.74 ± 0.51 mM, which was proved to be a competitive and concentration-dependent inhibition with slow-binding progress curves. The rapid formation of initial BA-urease complex with an inhibition constant of K(i) = 3.89 × 10⁻³ mM was followed by a slow isomerization into the final complex with an overall inhibition constant of K(i)* = 1.47 × 10⁻4 mM. High effectiveness of thiol protectors against BA inhibition indicated that the strategic role of the active-site sulfhydryl group of the urease was involved in the blocking process. Moreover, the inhibition of BA was proved to be reversible due to the fact that urease could be reactivated by dithiothreitol but not reactant dilution. Molecular docking assay suggested that BA made contacts with the important activating sulfhydryl group Cys-592 residues and restricted the mobility of the active-site flap. Taken together, it could be deduced that BA was a competitive inhibitor targeting thiol groups of urease in a slow-binding manner both reversibly and concentration-dependently, serving as a promising urease inhibitor for treatments on urease-related diseases.

Synthesis and antimicrobial evaluation of pogostone and its analogues.

Pogostone (PO) is one of the secondary metabolites from Pogostemon cablin (Blanco) Benth. (Lamiaceae), serving as the effective component of the antimicrobial activity. In this study, PO and a series of its analogues were synthesized by the reaction of dehydroacetate and aldehydes in tetrahydrofuran under a nitrogen atmosphere. Their activities against Candida albicans, Gram positive bacteria and Gram negative bacteria were evaluated. The antifungal results demonstrated that PO (MIC ranged from 12 to 97µg/mL against all strains, MFC ranged from 49 to 97µg/mL against all strains) and A3 (MIC ranged from 12 to 49, MFC over 195µg/mL) showed a strong activity against Candida albicans. While A1 (MIC ranged from 49 to 97µg/mL) and A2 (MIC ranged from 24 to 49µg/mL) have only shown effect against Guangzhou clinical isolates, the antibacterial results demonstrated that PO and its analogues showed no effects against the tested bacteria strains. This study suggests that pogostone analogues, with the appropriated structure modification, represented a kind of promising antifungal agents.

Oral administration of patchouli alcohol isolated from Pogostemonis Herba augments protection against influenza viral infection in mice.

Seasonal influenza A infection results in considerable morbidity and mortality. The limited efficacy of available therapeutic strategies stresses the need for development and study of new molecules against influenza virus (IFV). Patchouli alcohol (PA), the major chemical constituent of Pogostemonis Herba, was previously found to strongly inhibit influenza H1N1 replication in vitro. In the present study, the in vivo anti-IFV effect of PA was investigated. In a mouse model infected with lethal levels of FM1, oral administration of PA (20 mg/kg to 80 mg/kg) for 7 d post IFV infection significantly increased the survival rate and survival time. For IFV infection at nonlethal levels, the quantity of IFV in the lungs 5 d after infection was significantly reduced after PA (20 mg/kg to 80 mg/kg) administration. Anti-IFV IgA, IgM, and IgG titers in serum on day 6 were significantly higher in the PA-treated group than the IFV-control group. Anti-IFV immune response augmentation was further confirmed by the elevated production of CD3+, CD4+, and CD8+ T cell levels in blood. Furthermore, the levels of inflammatory cytokines, including TNF-alpha, IL-10 and IFN-gamma in serum of mice, were regulated. Lung inflammation was reduced significantly after PA administration, and the effect may be mediated, at least in part, by regulating the lung levels of inflammatory cytokines. Thus, oral administration of PA appears to be able to augment protection against IFV infection in mice via enhancement of host immune responses, and attenuation of systemic and pulmonary inflammatory responses.

Anti-inflammatory activity of patchouli alcohol isolated from Pogostemonis Herba in animal models.

Pogostemonis Herba has long been used in traditional Chinese medicine for the treatment of inflammatory disorders. Patchouli alcohol (PA), a tricyclic sesquiterpene isolated from Pogostemonis Herba, is known to possess a variety of pharmacological activities. The present study aimed to investigate the in vivo anti-inflammatory effect of PA using two common inflammatory animal models i.e., xylene-induced ear edema in mice and carrageenan-induced paw edema in rats. The degree of edema in both inflammatory animals, as well as the protein and mRNA expression of some inflammatory mediators including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), prostaglandin E2 (PGE2) and nitric oxide (NO) in the hind paw of carrageenan-treated rats were measured. Results showed that PA (10-40 mg/kg) significantly inhibited the ear edema induced by xylene in mice and the paw edema induced by carrageenan in rats. In addition, treatment with PA (10-40 mg/kg) also dose-dependently decreased the production of TNF-α, IL-1ß, PGE2 and NO in the hind paw of carrageenan-treated rats. Furthermore, PA treatment also suppressed the mRNA expression of TNF-α, IL-1ß, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the hind paw of carrageenan-treated rats. These results suggest that PA possesses potent anti-inflammatory activity, which may be mediated, at least in part, by down-regulating the mRNA expression of a panel of inflammatory mediators including TNF-α, IL-1ß, iNOS and COX-2.

[The effect of HJ-1 NO--HFJV respirator on treating pulmonary edema caused by seawater drowning].

The study was to observe the therapeutic effect of HJ-1 NO--HFJV respirator on treating pulmonary edema caused by seawater drowning. Seawater was infused into the rabbit's lung to establish the animal model of pulmonary edema caused by seawater drowning(PE-SWD). Then the animals were divided into three groups: simple PE-SWD model as control group, treat group(animal model treated with HFJV respirator and four medicines) and HFJV respiratior plus NO group. Pao2, Sao2 and pH were measured by the blood-gas analyzer. The survival time and seawater drowing-respiratiory distress syndrom(SW-RDS) were observed. The results showed that Pao2, Sao2 in NO group were remarkably higher than that of PE-SWD control group, and the survival time was longer than that of medicine treated group and the incidence of SW-RDS decreased to zero. We assume that HJ-1 NO-HFJV respirator is efficient on treating pulmonary edema.