Background and Purpose
Atrial metabolic remodelling is critical for the process of atrial fibrillation (AF). The PPAR‐α/sirtuin 1 /PPAR co‐activator α (PGC‐1α) pathway plays an important role in ...maintaining energy metabolism. However, the effect of the PPAR‐α agonist fenofibrate on AF is unclear. Therefore, the aim of this study was to determine the effect of fenofibrate on atrial metabolic remodelling in AF and explore its possible mechanisms of action.
Experimental Approach
The expression of metabolic proteins was examined in the left atria of AF patients. Thirty‐two rabbits were divided into sham, AF (pacing with 600 beats·min−1 for 1 week), fenofibrate treated (pretreated with fenofibrate before pacing) and fenofibrate alone treated (for 2 weeks) groups. HL‐1 cells were subjected to rapid pacing in the presence or absence of fenofibrate, the PPAR‐α antagonist GW6471 or sirtuin 1‐specific inhibitor EX527. Metabolic factors, circulating biochemical metabolites, atrial electrophysiology, adenine nucleotide levels and accumulation of glycogen and lipid droplets were assessed.
Key Results
The PPAR‐α/sirtuin 1/PGC‐1α pathway was significantly inhibited in AF patients and in the rabbit/HL‐1 cell models, resulting in a reduction of key downstream metabolic factors; this effect was significantly restored by fenofibrate. Fenofibrate prevented the alterations in circulating biochemical metabolites, reduced the level of adenine nucleotides and accumulation of glycogen and lipid droplets, reversed the shortened atrial effective refractory period and increased risk of AF.
Conclusion and Implications
Fenofibrate inhibited atrial metabolic remodelling in AF by regulating the PPAR‐α/sirtuin 1/PGC‐1α pathway. The present study may provide a novel therapeutic strategy for AF.
Squalene, a valuable acyclic triterpene, can be used as a chemical commodity for pharmacology, flavor, and biofuel industries. Microbial production of squalene has been of great interest due to its ...limited availability, and increasing prices extracted from animal and plant tissues. Here we report genetic perturbations that synergistically improve squalene production in Saccharomyces cerevisiae. As reported previously, overexpression of a truncated HMG‐CoA reductase 1 (tHMG1) led to the accumulation 20‐fold higher squalene than a parental strain. In order to further increase squalene accumulation in the tHMG1 overexpressing yeast, we introduced genetic perturbations—known to increase lipid contents in yeast—to enhance squalene accumulation as lipid body is a potential storage of squalene. Specifically, DGA1 coding for diacylglycerol acyltranferase was overexpressed to enhance lipid biosynthesis, and POX1 and PXA2 coding for acyl‐CoA oxidase and a subunit of peroxisomal ABC transporter were deleted to reduce lipid β‐oxidation. Simultaneous overexpression of tHMG1 and DGA1 coding for rate‐limiting enzymes in the mevalonate and lipid biosynthesis pathways led to over 250‐fold higher squalene accumulation than a control strain. However, deletion of POX1 and PXA2 in the tHMG1 overexpressing yeast did not improve squalene accumulation additionally. Fed‐batch fermentation of the tHMG1 and DGA1 co‐overexpressing yeast strain resulted in the production of squalene at a titer of 445.6 mg/L in a nitrogen‐limited minimal medium. This report demonstrates that increasing storage capacity for hydrophobic compounds can enhance squalene production, suggesting that increasing lipid content is an effective strategy to overproduce a hydrophobic molecule in yeast.
This study focused on the genetic perturbations eliciting improved lipid production and enhanced squalene accumulation in Saccharomyces cerevisiae. The engineered strains, with simultaneous overexpression of tHMG1 and DGA1 coding for rate‐limiting enzymes in the mevalonate and lipid biosynthesis pathways, showed over 250‐fold higher squalene accumulation than a control strain. The results indicated that increasing storage capacity for hydrophobic compounds enhances squalene production.
Purely organic room-temperature phosphorescence has attracted attention for bioimaging but can be quenched in aqueous systems. Here we report a water-soluble ultralong organic room-temperature ...phosphorescent supramolecular polymer by combining cucurbitnuril (CB7, CB8) and hyaluronic acid (HA) as a tumor-targeting ligand conjugated to a 4-(4-bromophenyl)pyridin-1-ium bromide (BrBP) phosphor. The result shows that CB7 mediated pseudorotaxane polymer CB7/HA-BrBP changes from small spherical aggregates to a linear array, whereas complexation with CB8 results in biaxial pseudorotaxane polymer CB8/HA-BrBP which transforms to relatively large aggregates. Owing to the more stable 1:2 inclusion complex between CB8 and BrBP and the multiple hydrogen bonds, this supramolecular polymer has ultralong purely organic RTP lifetime in water up to 4.33 ms with a quantum yield of 7.58%. Benefiting from the targeting property of HA, this supramolecular polymer is successfully applied for cancer cell targeted phosphorescence imaging of mitochondria.
Traumatic brain injury (TBI) is a dominant cause of death and permanent disability worldwide. Although TBI could significantly increase the proliferation of adult neural stem cells in the ...hippocampus, the survival and maturation of newborn cells is markedly low. Increasing evidence suggests that the secretome derived from mesenchymal stem cells (MSCs) would be an ideal alternative to MSC transplantation. The successive and microenvironmentally responsive secretion in MSCs may be critical for the functional benefits provided by transplanted MSCs after TBI. Therefore, it is reasonable to hypothesize that the signaling molecules secreted in response to local tissue damage can further facilitate the therapeutic effect of the MSC secretome. To simulate the complex microenvironment in the injured brain well, we used traumatically injured brain tissue extracts to pretreat umbilical cord mesenchymal stem cells (UCMSCs) in vitro and stereotaxically injected the secretome from traumatic injury‐preconditioned UCMSCs into the dentate gyrus of the hippocampus in a rat severe TBI model. The results revealed that compared with the normal secretome, the traumatic injury‐preconditioned secretome could significantly further promote the differentiation, migration, and maturation of newborn cells in the dentate gyrus and ultimately improve cognitive function after TBI. Cytokine antibody array suggested that the increased benefits of secretome administration were attributable to the newly produced proteins and up‐regulated molecules from the MSC secretome preconditioned by a traumatically injured microenvironment. Our study utilized the traumatic injury‐preconditioned secretome to amplify neurogenesis and improve cognitive recovery, suggesting this method may be a novel and safer candidate for nerve repair.
Cover Image for this issue: doi: 10.1111/jnc.14741
To most closely replicate the complex microenvironment in injured brain, we used extract of traumatic brain tissue to preconditioning umbilical cord mesenchymal stem cells (MSCs) in vitro, and stereotaxically injected these secretome into dentate gyrus of hippocampus in a rat severe Traumatic brain injury (TBI) model. We observed that traumatically preconditioning secretome could significantly further promote the differentiation, migration and maturation of newborn cells in dentate gyrus, and finally improved the cognitive function after TBI. Our study utilized the injury‐preconditioning secretome to inducibly amplify the neurogenesis and cognitive recovery, which can offers a novel and safer candidate for nerve repair.
Open Science: This manuscript was awarded with the Open Materials Badge
For more information see: https://cos.io/our-services/open-science-badges/
Cover Image for this issue: doi: 10.1111/jnc.14741
ABSTRACT
Here, through single‐molecule real‐time sequencing, we present a high‐quality genome sequence of the Japanese larch (Larix kaempferi), a conifer species with great value for wood production ...and ecological afforestation. The assembled genome is 10.97 Gb in size, harboring 45,828 protein‐coding genes. Of the genome, 66.8% consists of repeat sequences, of which long terminal repeat retrotransposons are dominant and make up 69.86%. We find that tandem duplications have been responsible for the expansion of genes involved in transcriptional regulation and stress responses, unveiling their crucial roles in adaptive evolution. Population transcriptome analysis reveals that lignin content in L. kaempferi is mainly determined by the process of monolignol polymerization. The expression values of six genes (LkCOMT7, LkCOMT8, LkLAC23, LkLAC102, LkPRX148, and LkPRX166) have significantly positive correlations with lignin content. These results indicated that the increased expression of these six genes might be responsible for the high lignin content of the larches' wood. Overall, this study provides new genome resources for investigating the evolution and biological function of conifer trees, and also offers new insights into wood properties of larches.
Examination of the high‐quality genome of the Japanese larch Larix kaempferi reveals key features of this tree species and illustrates the crucial roles of genes encoding laccase and Class III peroxidases in wood properties of conifers.
Background
To reveal detailed histopathological changes, virus distributions, immunologic properties and multi‐omic features caused by SARS‐CoV‐2 in the explanted lungs from the world's first ...successful lung transplantation of a COVID‐19 patient.
Materials and methods
A total of 36 samples were collected from the lungs. Histopathological features and virus distribution were observed by optical microscope and transmission electron microscope (TEM). Immune cells were detected by flow cytometry and immunohistochemistry. Transcriptome and proteome approaches were used to investigate main biological processes involved in COVID‐19‐associated pulmonary fibrosis.
Results
The histopathological changes of the lung tissues were characterized by extensive pulmonary interstitial fibrosis and haemorrhage. Viral particles were observed in the cytoplasm of macrophages. CD3+CD4− T cells, neutrophils, NK cells, γ/δ T cells and monocytes, but not B cells, were abundant in the lungs. Higher levels of proinflammatory cytokines iNOS, IL‐1β and IL‐6 were in the area of mild fibrosis. Multi‐omics analyses revealed a total of 126 out of 20,356 significant different transcription and 114 out of 8,493 protein expression in lung samples with mild and severe fibrosis, most of which were related to fibrosis and inflammation.
Conclusions
Our results provide novel insight that the significant neutrophil/ CD3+CD4− T cell/ macrophage activation leads to cytokine storm and severe fibrosis in the lungs of COVID‐19 patient and may contribute to a better understanding of COVID‐19 pathogenesis.
Downregulating programmed cell death ligand 1(PD‐L1) protein levels in tumor cells is an effective way to achieve immune system activation for oncology treatment, but current strategies are ...inadequate. Here, we design a caged peptide‐AIEgen probe (GCP) to self‐assemble with miR‐140 forming GCP/miR‐140 nanoparticles. After entering tumor cells, GCP/miR‐140 disassembles in the presence of Cathepsin B (CB) and releases caged GO203 peptide, miR‐140 and PyTPA. Peptide decages in the highly reductive intracellular environment and binds to mucin 1 (MUC1), thereby downregulating the expression of PD‐L1. Meanwhile, miR‐140 reduces PD‐L1 expression by targeting downregulation of PD‐L1 mRNA. Under the action of PyTPA‐mediated photodynamic therapy (PDT), tumor‐associated antigens are released, triggering immune cell attack on tumor cells. This multiple mechanism‐based strategy of deeply downregulating PD‐L1 in tumor cells activates the immune system and thus achieves effective immunotherapy.
In tumor cells, a caged peptide‐AIEgen probe self‐assembled with miR‐140 could release the GO203 peptide binding to MUC1 and miR‐140 degrading the PD‐L1 mRNA, thus, achieving the deep downregulation of the PD‐L1 expression. Subsequently, activated immune cells by PDT‐induced release of TAAs would achieve more effective immunotherapy.
Currently, there is no strong evidence of the well-established biomarkers for immune checkpoint inhibitors (ICIs) in nasopharyngeal carcinoma (NPC). Here, we aimed to reveal the heterogeneity of ...tumour microenvironment (TME) through virtual microdissection of gene expression profiles. An immune-enriched subtype was identified in 38% (43/113) of patients, which was characterized by significant enrichment of immune cells or immune responses. The remaining patients were therefore classified as a non-Immune Subtype (non-IS), which exhibited highly proliferative features. Then we identified a tumour immune evasion state within the immune-enriched subtype (18/43, 42%), in which high expression of exclusion- and dysfunction-related signatures was observed. These subgroups were designated the Evaded and Active Immune Subtype (E-IS and A-IS), respectively. We further demonstrated that A-IS predicted favourable survival and improved ICI response as compared to E-IS and non-IS. In summary, this study introduces the novel immune subtypes and demonstrates their feasibility in tailoring immunotherapeutic strategies.
Fibrosis serves a critical role in driving atrial remodelling‐mediated atrial fibrillation (AF). Abnormal levels of the transcription factor PU.1, a key regulator of fibrosis, are associated with ...cardiac injury and dysfunction following acute viral myocarditis. However, the role of PU.1 in atrial fibrosis and vulnerability to AF remain unclear. Here, an in vivo atrial fibrosis model was developed by the continuous infusion of C57 mice with subcutaneous Ang‐II, while the in vitro model comprised atrial fibroblasts that were isolated and cultured. The expression of PU.1 was significantly up‐regulated in the Ang‐II‐induced group compared with the sham/control group in vivo and in vitro. Moreover, protein expression along the TGF‐β1/Smads pathway and the proliferation and differentiation of atrial fibroblasts induced by Ang‐II were significantly higher in the Ang‐II‐induced group than in the sham/control group. These effects were attenuated by exposure to DB1976, a PU.1 inhibitor, both in vivo and in vitro. Importantly, in vitro treatment with small interfering RNA against Smad3 (key protein of TGF‐β1/Smads signalling pathway) diminished these Ang‐II‐mediated effects, and the si‐Smad3‐mediated effects were, in turn, antagonized by the addition of a PU.1‐overexpression adenoviral vector. Finally, PU.1 inhibition reduced the atrial fibrosis induced by Ang‐II and attenuated vulnerability to AF, at least in part through the TGF‐β1/Smads pathway. Overall, the study implicates PU.1 as a potential therapeutic target to inhibit Ang‐II‐induced atrial fibrosis and vulnerability to AF.
This is the first randomised controlled trial for assessment of the immunogenicity and safety of a candidate non-replicating adenovirus type-5 (Ad5)-vectored COVID-19 vaccine, aiming to determine an ...appropriate dose of the candidate vaccine for an efficacy study.
This randomised, double-blind, placebo-controlled, phase 2 trial of the Ad5-vectored COVID-19 vaccine was done in a single centre in Wuhan, China. Healthy adults aged 18 years or older, who were HIV-negative and previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection-free, were eligible to participate and were randomly assigned to receive the vaccine at a dose of 1 × 1011 viral particles per mL or 5 × 1010 viral particles per mL, or placebo. Investigators allocated participants at a ratio of 2:1:1 to receive a single injection intramuscularly in the arm. The randomisation list (block size 4) was generated by an independent statistician. Participants, investigators, and staff undertaking laboratory analyses were masked to group allocation. The primary endpoints for immunogenicity were the geometric mean titres (GMTs) of specific ELISA antibody responses to the receptor binding domain (RBD) and neutralising antibody responses at day 28. The primary endpoint for safety evaluation was the incidence of adverse reactions within 14 days. All recruited participants who received at least one dose were included in the primary and safety analyses. This study is registered with ClinicalTrials.gov, NCT04341389.
603 volunteers were recruited and screened for eligibility between April 11 and 16, 2020. 508 eligible participants (50% male; mean age 39·7 years, SD 12·5) consented to participate in the trial and were randomly assigned to receive the vaccine (1 × 1011 viral particles n=253; 5 × 1010 viral particles n=129) or placebo (n=126). In the 1 × 1011 and 5 × 1010 viral particles dose groups, the RBD-specific ELISA antibodies peaked at 656·5 (95% CI 575·2–749·2) and 571·0 (467·6–697·3), with seroconversion rates at 96% (95% CI 93–98) and 97% (92–99), respectively, at day 28. Both doses of the vaccine induced significant neutralising antibody responses to live SARS-CoV-2, with GMTs of 19·5 (95% CI 16·8–22·7) and 18·3 (14·4–23·3) in participants receiving 1 × 1011 and 5 × 1010 viral particles, respectively. Specific interferon γ enzyme-linked immunospot assay responses post vaccination were observed in 227 (90%, 95% CI 85–93) of 253 and 113 (88%, 81–92) of 129 participants in the 1 × 1011 and 5 × 1010 viral particles dose groups, respectively. Solicited adverse reactions were reported by 183 (72%) of 253 and 96 (74%) of 129 participants in the 1 × 1011 and 5 × 1010 viral particles dose groups, respectively. Severe adverse reactions were reported by 24 (9%) participants in the 1 × 1011 viral particles dose group and one (1%) participant in the 5 × 1010 viral particles dose group. No serious adverse reactions were documented.
The Ad5-vectored COVID-19 vaccine at 5 × 1010 viral particles is safe, and induced significant immune responses in the majority of recipients after a single immunisation.
National Key R&D Programme of China, National Science and Technology Major Project, and CanSino Biologics.
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