Deep learning facilitated superhigh-resolution recognition of structured light ellipticities.

Elliptical beams (EBs), an essential family of structured light, have been investigated theoretically due to their intriguing mathematical properties. However, their practical application has been significantly limited due to the inability to determine all their physical quantities, particularly the ellipticity factor, a unique parameter for EBs of different families. In this paper, to our knowledge, we proposed the first high-accuracy approach that can effectively distinguish EBs with an ellipticity factor difference of 0.01, equivalent to 99.9% field similarities. The method is based on a transformer deep learning (DL) network, and the accuracy has reached 99% for two distinct families of exemplified EBs. To prove that the high performance of this model can dramatically extend the practical aspect of EBs, we used EBs as information carriers in free-space optical communication for an image transmission task, and an error bit rate as low as 0.22% is achieved. Advancing the path of such a DL approach will facilitate the research of EBs for many practical applications such as optical imaging, optical sensing, and quantum-related systems.

Altered lipid metabolism promoting cardiac fibrosis is mediated by CD34+ cell-derived FABP4+ fibroblasts.

Hyperlipidemia and hypertension might play a role in cardiac fibrosis, in which a heterogeneous population of fibroblasts seems important. However, it is unknown whether CD34+ progenitor cells are involved in the pathogenesis of heart fibrosis. This study aimed to explore the mechanism of CD34+ cell differentiation in cardiac fibrosis during hyperlipidemia. Through the analysis of transcriptomes from 50,870 single cells extracted from mouse hearts and 76,851 single cells from human hearts, we have effectively demonstrated the evolving cellular landscape throughout cardiac fibrosis. Disturbances in lipid metabolism can accelerate the development of fibrosis. Through the integration of bone marrow transplantation models and lineage tracing, our study showed that hyperlipidemia can expedite the differentiation of non-bone marrow-derived CD34+ cells into fibroblasts, particularly FABP4+ fibroblasts, in response to angiotensin II. Interestingly, the partial depletion of CD34+ cells led to a notable reduction in triglycerides in the heart, mitigated fibrosis, and improved cardiac function. Furthermore, immunostaining of human heart tissue revealed colocalization of CD34+ cells and fibroblasts. Mechanistically, our investigation of single-cell RNA sequencing data through pseudotime analysis combined with in vitro cellular studies revealed the crucial role of the PPARγ/Akt/Gsk3ß pathway in orchestrating the differentiation of CD34+ cells into FABP4+ fibroblasts. Through our study, we generated valuable insights into the cellular landscape of CD34+ cell-derived cells in the hypertrophic heart with hyperlipidemia, indicating that the differentiation of non-bone marrow-derived CD34+ cells into FABP4+ fibroblasts during this process accelerates lipid accumulation and promotes heart failure via the PPARγ/Akt/Gsk3ß pathway.

TUDCA alleviates atherosclerosis by inhibiting AIM2 inflammasome and enhancing cholesterol efflux capacity in macrophage.

Cholesterol efflux capacity (CEC) dysfunction in macrophages is important in atherosclerosis. However, the mechanism underlying CEC dysfunction remains unclear. We described the characteristics of ATF4 and inflammasome activation in macrophages during atherosclerosis through scRNA sequencing analysis. Then model of hyperlipemia was established in ApoE-/- mice; some were treated with tauroursodeoxycholic acid (TUDCA). TUDCA decreased the ATF4, Hspa, and inflammasome activation, reduced plaque area of the artery, and promoted CEC in macrophages. Furthermore, TUDCA abolished oxLDL-induced foam cell formation by inhibiting activation of the PERK/eIF2α/ATF4 and AIM2 inflammasome in macrophages. Further assays revealed ATF4 binding to AIM2 promoter, promoting its transcriptional activity significantly. Then we discovered that ATF4 affected AIM2-mediated foam cell formation by targeting ABCA1, which could be blocked by TUDCA. Our study demonstrated that TUDCA alleviates atherosclerosis by inhibiting AIM2 inflammasome and enhancing CEC of macrophage, which provided possibilities for the development of therapies.

Conventional dendritic cells 2, the targeted antigen-presenting-cell, induces enhanced type 1 immune responses in mice immunized with CVC1302 in oil formulation.

Multifunctional CD4+ T helper 1 (Th1) cells, producing IFN-γ, TNF-α and IL-2, define a correlate of vaccine-mediated protection against intracellular infection. In our previous study, we found that CVC1302 in oil formulation promoted the differentiation of IFN-γ+/TNF-α+/IL-2+Th1 cells. In order to extend the application of CVC1302 in oil formulation, this study aimed to elucidate the mechanism of action in improving the Th1 immune response. Considering the signals required for the differentiation of CD4+ T cells to Th1 cells, we detected the distribution of innate immune cells and the model antigen OVA-FITC in lymph node (LN), as well as the quantity of cytokines produced by the innate immune cells. The results of these experiments show that, cDC2 and OVA-FITC localized to interfollicular region (IFR) of the draining lymph nodes, inflammatory monocytes localized to both IFR and T cell zone, which mainly infiltrate from the blood. In this inflammatory niche within LN, CD4+ T cells were attracted into IFR by CXCL10, secreted by inflammatory monocytes, then activated by cDC2, secreting IL-12. Above all, CVC1302 in oil formulation, on the one hand, targeted antigen and inflammatory monocytes into the LN IFR in order to attract CD4+ T cells, on the other hand, targeted cDC2 to produce IL-12 in order to promote optimal Th1 differentiation. The new finding will provide a blueprint for application of immunopotentiators in optimal formulations.

Epicardial CCM2 Promotes Cardiac Development and Repair Via its Regulation on Cytoskeletal Reorganization.

The epicardium provides epicardial-derived cells and molecular signals to support cardiac development and regeneration. Zebrafish and mouse studies have shown that ccm2, a cerebral cavernous malformation disease gene, is essential for cardiac development. Endocardial cell-specific deletion of Ccm2 in mice has previously established that Ccm2 is essential for maintenance of the cardiac jelly for cardiac development during early gestation. The current study aimed to explore the function of Ccm2 in epicardial cells for heart development and regeneration. Through genetic deletion of Ccm2 in epicardial cells, our in vivo and ex vivo experiments revealed that Ccm2 is required by epicardial cells to support heart development. Ccm2 regulates epicardial cell adhesion, cell polarity, cell spreading, and migration. Importantly, the loss of Ccm2 in epicardial cells delays cardiac function recovery and aggravates cardiac fibrosis following myocardial infarction. Molecularly, Ccm2 targets the production of cytoskeletal and matrix proteins to maintain epicardial cell function and behaviors. Epicardial Ccm2 plays a critical role in heart development and regeneration via its regulation of cytoskeleton reorganization.

Topological state transitions of skyrmionic beams under focusing configurations.

The recent emerging appearance of optical analogs of magnetic quasiparticles, i.e., optical skyrmions constructed via spin, field, and Stokes vectors, has garnered substantial interest from deep-subwavelength imaging and quantum entanglement. Here, we investigate systematically the topological state transitions of skyrmionic beams constructed by the Stokes vectors in the focusing configuration. We theoretically demonstrated that in the weak focusing, the skyrmion topological number is protected. Whereas, in the tight focusing, a unique topological transformation with skyrmion number variation is exhibited for the optical skyrmion, anti-skyrmion, and 2nd-order skyrmion structures. The significant difference between the topological state transitions of these two cases originates from the transformation from the paraxial optical system to the nonparaxial optical system, and the approximate two-dimensional polarization structure to the three-dimensional polarization structure. The results provide new insights into the topological state transitions in topological structures, which promote applications in information processing, data storage, and free-space optical communications.

Analysis of CVC1302-Mediated Enhancement of Monocyte Recruitment in Inducing Immune Responses.

Monocytes (Mos) are believed to play important roles during the generation of immune response. In our previous study, CVC1302, a complex of PRRs agonists, was demonstrated to recruit Mo into lymph nodes (LNs) in order to present antigen and secret chemokines (CXCL9 and CXCL10), which attracted antigen-specific CD4+ T cells. As it is known that Mos in mice are divided into two main Mo subsets (Ly6C+ Mo and Ly6C- Mo), we aimed to clarify the CVC1302-recruiting Mo subset and functions in the establishment of immunity. In this study, we found that CVC1302 attracted both Ly6C+ Mo and Ly6C- Mo into draining LNs, which infiltrated from different origins, injection muscles and high endothelial venule (HEV), respectively. We also found that the numbers of OVA+ Ly6C+ Mo in the draining LNs were significantly higher compared with OVA+ Ly6C- Mo. However, the levels of CXCL9 and CXCL10 produced by Ly6C- Mo were significantly higher than Ly6C+ Mo, which plays important roles in attracting antigen-specific CD4+ T cells. Under the analysis of their functions in initiating immune responses, we found that the ability of the Ly6C+ monocyte was mainly capturing and presenting antigens, otherwise; the ability of the Ly6C- monocyte was mainly secreting CXCL9 and CXCL10, which attracted antigen-specific CD4+ T cells through CXCR3. These results will provide new insights into the development of new immunopotentiators and vaccines.

Increases in Cellular Immune Responses Due to Positive Effect of CVC1302-Induced Lysosomal Escape in Mice.

This study found a higher percentage of CD8+ T cells in piglets immunized with a CVC1302-adjuvanted inactivated foot-and-mouth disease virus (FMDV) vaccine. We wondered whether the CVC1302-adjuvanted inactivated FMDV vaccine promoted cellular immunity by promoting the antigen cross-presentation efficiency of ovalbumin (OVA) through dendritic cells (DCs), mainly via cytosolic pathways. This was demonstrated by the enhanced levels of lysosomal escape of OVA in the DCs loaded with OVA and CVC1302. The higher levels of ROS and significantly enhanced elevated lysosomal pH levels in the DCs facilitated the lysosomal escape of OVA. Significantly enhanced CTL activity levels was observed in the mice immunized with OVA-CVC1302. Overall, CVC1302 increased the cross-presentation of exogenous antigens and the cross-priming of CD8+ T cells by alkalizing the lysosomal pH and facilitating the lysosomal escape of antigens. These studies shed new light on the development of immunopotentiators to improve cellular immunity induced by vaccines.

Stem cell antigen-1+cell-derived fibroblasts are crucial for cardiac fibrosis during heart failure.

AIMS: Mesenchymal stem cells (MSCs) present in the heart cannot differentiate into cardiomyocytes, but may play a role in pathological conditions. Therefore, the aim of this study was to scrutinise the role and mechanism of MSC differentiation in vivo during heart failure. METHODS AND RESULTS: We performed single-cell RNA sequencing of total non-cardiomyocytes from murine and adult human hearts. By analysing the transcriptomes of single cells, we illustrated the dynamics of the cell landscape during the progression of heart hypertrophy, including those of stem cell antigen-1 (Sca1)+ stem/progenitor cells and fibroblasts. By combining genetic lineage tracing and bone marrow transplantation models, we demonstrated that non-bone marrow-derived Sca1+ cells give rise to fibroblasts. Interestingly, partial depletion of Sca1+ cells alleviated the severity of myocardial fibrosis and led to a significant improvement in cardiac function in Sca1-CreERT2;Rosa26-eGFP-DTA mice. Similar non-cardiomyocyte cell composition and heterogeneity were observed in human patients with heart failure. Mechanistically, our study revealed that Sca1+ cells can transform into fibroblasts and affect the severity of fibrosis through the Wnt4-Pdgfra pathway. CONCLUSIONS: Our study describes the cellular landscape of hypertrophic hearts and reveals that fibroblasts derived from Sca1+ cells with a non-bone marrow source largely account for cardiac fibrosis. These findings provide novel insights into the pathogenesis of cardiac fibrosis and have potential therapeutic implications for heart failure. Non-bone marrow-derived Sca1+ cells differentiate into fibroblasts involved in cardiac fibrosis via Wnt4-PDGFRα pathway.

Multilineage commitment of Sca-1+ cells in reshaping vein grafts.

Vein graft failure remains a significant clinical problem. Similar to other vascular diseases, stenosis of vein grafts is caused by several cell lines; however, the sources of these cells remain unclear. The objective of this study was to investigate the cellular sources that reshape vein grafts. By analyzing transcriptomics data and constructing inducible lineage-tracing mouse models, we investigated the cellular components of vein grafts and their fates. The sc-RNAseq data suggested that Sca-1+ cells were vital players in vein grafts and might serve as progenitors for multilineage commitment. By generating a vein graft model in which the venae cavae from C57BL/6J wild-type mice were transplanted adjacent to the carotid arteries of Sca-1(Ly6a)-CreERT2; Rosa26-tdTomato mice, we demonstrated that the recipient Sca-1+ cells dominated reendothelialization and the formation of adventitial microvessels, especially at the perianastomotic regions. In turn, using chimeric mouse models, we confirmed that the Sca-1+ cells that participated in reendothelialization and the formation of adventitial microvessels all had a non-bone-marrow origin, whereas bone-marrow-derived Sca-1+ cells differentiated into inflammatory cells in vein grafts. Furthermore, using a parabiosis mouse model, we confirmed that non-bone-marrow-derived circulatory Sca-1+ cells were vital for the formation of adventitial microvessels, whereas Sca-1+ cells derived from local carotid arteries were the source of endothelium restoration. Using another mouse model in which venae cavae from Sca-1 (Ly6a)-CreERT2; Rosa26-tdTomato mice were transplanted adjacent to the carotid arteries of C57BL/6J wild-type mice, we confirmed that the donor Sca-1+ cells were mainly responsible for smooth muscle cells commitment in the neointima, particularly at the middle bodies of vein grafts. In addition, we provided evidence that knockdown/knockout of Pdgfrα in Sca-1+ cells decreased the cell potential to generate SMCs in vitro and decreased number of intimal SMCs in vein grafts. Our findings provided cell atlases of vein grafts, which demonstrated that recipient carotid arteries, donor veins, non-bone-marrow circulation, and the bone marrow provided diverse Sca-1+ cells/progenitors that participated in the reshaping of vein grafts.

Multilineage contribution of CD34+ cells in cardiac remodeling after ischemia/reperfusion injury.

The ambiguous results of multiple CD34+ cell-based therapeutic trials for patients with heart disease have halted the large-scale application of stem/progenitor cell treatment. This study aimed to delineate the biological functions of heterogenous CD34+ cell populations and investigate the net effect of CD34+ cell intervention on cardiac remodeling. We confirmed, by combining single-cell RNA sequencing on human and mouse ischemic hearts and an inducible Cd34 lineage-tracing mouse model, that Cd34+ cells mainly contributed to the commitment of mesenchymal cells, endothelial cells (ECs), and monocytes/macrophages during heart remodeling with distinct pathological functions. The Cd34+-lineage-activated mesenchymal cells were responsible for cardiac fibrosis, while CD34+Sca-1high was an active precursor and intercellular player that facilitated Cd34+-lineage angiogenic EC-induced postinjury vessel development. We found through bone marrow transplantation that bone marrow-derived CD34+ cells only accounted for inflammatory response. We confirmed using a Cd34-CreERT2; R26-DTA mouse model that the depletion of Cd34+ cells could alleviate the severity of ventricular fibrosis after ischemia/reperfusion (I/R) injury with improved cardiac function. This study provided a transcriptional and cellular landscape of CD34+ cells in normal and ischemic hearts and illustrated that the heterogeneous population of Cd34+ cell-derived cells served as crucial contributors to cardiac remodeling and function after the I/R injury, with their capacity to generate diverse cellular lineages.

Promoting immunity with novel targeting antigen delivery vehicle based on bispecific nanobody.

As the most potent professional antigen presenting cells, dendritic cells (DCs) have been targeted in strategies to enhance vaccination efficacy. To date, targeted delivery has been mainly used for cancer therapy, with few studies focusing on vaccine antigens for animal epidemic diseases. In this study, we selected a series of mouse DC-specific nanobodies from a non-immunized camel. The four candidate nanobodies identified (Nb4, Nb13, Nb17, and Nb25), which showed efficient endocytosis of bone marrow-derived DCs, were evaluated as potential vaccine antigen targeted delivery vehicles. First, green fluorescent protein (GFP) was selected and four corresponding DCNb-GFP fusions were constructed for verification. Nb17-GFP was effective at promoting antibody production, inducing a cellular immune response, and increasing the IL-4 level. Second, foot-and-mouth disease virus (FMDV) and a FMDV-specific nanobody (Nb205) were selected and four bispecific nanobody DCNb-Nb205 fusions were generated to investigate the feasibility of a novel targeting antigen delivery vehicle. The resulting bispecific nanobody, Nb17-Nb205, could not only deliver FMDV particles instead of antigenic peptide, but also induced the production of specific antibodies, a cellular immune response, and IFN-γ and IL-4 levels upon immunization with a single subcutaneous injection. In conclusion, our results demonstrate the potential of bispecific nanobody as a novel and efficient DC-specific antigen delivery vehicle. This highlights the potential to expand targeted delivery to the field of animal epidemic diseases and provides a reference for the general application of nanotechnology in viral diseases.

The impact of hypertension for metabolites in patients with acute coronary syndrome.

Background: Acute coronary syndrome (ACS) is one of the leading causes of death and is often accompanied by hypertension. Methods: We investigated whether hypertension affects the metabolism of patients with ACS. Serum samples were provided from healthy controls (HCs; n=26), patients with ACS (n=20), or those patients with ACS complicated with hypertension (HTN, n=21), and all were subjected to non-targeted metabolomics analyses based on gas chromatography-mass spectrometry (GC/MS). Differential metabolites were screened using principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discriminant analysis (OPLS-DA). Kyoto Encyclopedia of Genes and Genomes (KEGG) provided metabolic pathways related to these metabolites. Results: Compared to those in the HC group, 12 metabolites were significantly upregulated and 6 significantly downregulated in the ACS group; among these, L-cystine and isocitric acid showed the most obvious differences, respectively. Compared to those in the ACS group, 3 metabolites were significantly upregulated and 2 metabolites were significantly downregulated in the ACS-HTN group, among which oleic acid and chenodeoxycholic acid showed the most marked difference, respectively. The five most prominent metabolic pathways involved in differential metabolites between the ACS and HC groups were arginine biosynthesis; oxidative phosphorylation; alanine, aspartate and glutamate metabolism; citrate cycle; and glucagon signaling pathway. The metabolic pathways between the ACS and ACS-HTN groups were steroid biosynthesis, fatty acid biosynthesis, arginine biosynthesis, primary bile acid biosynthesis, and tyrosine metabolism. Conclusions: A comprehensive study of the changes in circulatory metabolomics and the influence of HTN was conducted in patients with ACS. A serum metabolomics test can be used to identify differentially metabolized molecules and allow the classification of patients with ACS or those complicated with HTN.

Spin-Manipulated Photonic Skyrmion-Pair for Pico-Metric Displacement Sensing.

Photonic spin skyrmions with deep-subwavelength features have aroused considerable interest in recent years. However, the manipulation of spin structure in the skyrmions in a desired manner is still a challenge, while this is crucial for developing the skyrmion-based applications. Here, an approach of optical spin manipulation by utilizing the spin-momentum equation is proposed to investigate the spin texture in a photonic skyrmion-pair. With the benefit of the proposed approach, a unique spin texture with spin angular momentum varying linearly along the line connecting the two skyrmion centers is theoretically designed and experimentally verified. The optimized spin texture is then applied in a displacement-sensing system, which is capable of attaining pico-metric sensitivity. Compared with the conventional polarization and phase schemes, the spin-based manipulation mechanism provides a new pathway for optical modulation, which is of great value in nanophotonics from both fundamental and application.

Metastability of photonic spin meron lattices in the presence of perturbed spin-orbit coupling.

Photonic skyrmions and merons are topological quasiparticles characterized by nontrivial electromagnetic textures, which have received increasing research attention recently, providing novel degree of freedom to manipulate light-matter interactions and exhibiting excellent potential in deep-subwavelength imaging and nanometrology. Here, the topological stability of photonic spin meron lattices, which indicates the invariance of skyrmion number and robustness of spin texture under a continuous deformation of the field configuration, is demonstrated by inducing a perturbation to break the C4 symmetry in the presence spin-orbit coupling in an optical field. We revealed that amplitude perturbation would result in an amplitude-dependent shift of spin center, while phase perturbation leads to the deformation of domain walls, manifesting the metastability of photonic meron. Such spin topology is verified through the interference of plasmonic vortices with a broken rotational symmetry. The results provide new insights on optical topological quasiparticles, which may pave the way towards applications in topological photonics, optical information storage and transfer.

Single cell and lineage tracing studies reveal the impact of CD34+ cells on myocardial fibrosis during heart failure.

BACKGROUND: CD34+ cells have been used to treat the patients with heart failure, but the outcome is variable. It is of great significance to scrutinize the fate and the mechanism of CD34+ cell differentiation in vivo during heart failure and explore its intervention strategy. METHODS: We performed single-cell RNA sequencing (scRNA-seq) of the total non-cardiomyocytes and enriched Cd34-tdTomato+ lineage cells in the murine (male Cd34-CreERT2; Rosa26-tdTomato mice) pressure overload model (transverse aortic constriction, TAC), and total non-cardiomyocytes from human adult hearts. Then, in order to determine the origin of CD34+ cell that plays a role in myocardial fibrosis, bone marrow transplantation model was performed. Furthermore, to further clarify the role of CD34 + cells in myocardial remodeling in response to TAC injury, we generated Cd34-CreERT2; Rosa26-eGFP-DTA (Cre/DTA) mice. RESULTS: By analyzing the transcriptomes of 59,505 single cells from the mouse heart and 22,537 single cells from the human heart, we illustrated the dynamics of cell landscape during the progression of heart hypertrophy, including CD34+ cells, fibroblasts, endothelial and immune cells. By combining genetic lineage tracing and bone marrow transplantation models, we demonstrated that non-bone-marrow-derived CD34+ cells give rise to fibroblasts and endothelial cells, while bone-marrow-derived CD34+ cell turned into immune cells only in response to pressure overload. Interestingly, partial depletion of CD34+ cells alleviated the severity of myocardial fibrosis with a significant improvement of cardiac function in Cd34-CreERT2; Rosa26-eGFP-DTA model. Similar changes of non-cardiomyocyte composition and cellular heterogeneity of heart failure were also observed in human patient with heart failure. Furthermore, immunostaining showed a double labeling of CD34 and fibroblast markers in human heart tissue. Mechanistically, our single-cell pseudotime analysis of scRNA-seq data and in vitro cell culture study revealed that Wnt-ß-catenin and TGFß1/Smad pathways are critical in regulating CD34+ cell differentiation toward fibroblasts. CONCLUSIONS: Our study provides a cellular landscape of CD34+ cell-derived cells in the hypertrophy heart of human and animal models, indicating that non-bone-marrow-derived CD34+ cells differentiating into fibroblasts largely account for cardiac fibrosis. These findings may provide novel insights for the pathogenesis of cardiac fibrosis and have further potential therapeutic implications for the heart failure.

The AIM2 inflammasome: A novel biomarker and target in cardiovascular disease.

Absent in melanoma 2 (AIM2) is a cytoplasmic sensor that recognises the double-strand DNA. AIM2 inflammasome is a protein platform in the cell that initiates innate immune responses by cleaving pro-caspase-1 and converting IL-1ß and IL-18 to their mature forms. Additionally, AIM2 inflammasome promotes pyroptosis by converting Gasdermin-D (GSDMD) to GSDMD-N fragments. An increasing number of studies have indicated the important and decisive roles of the AIM2 inflammasome, IL-1ß, and pyroptosis in cardiovascular diseases, such as coronary atherosclerosis, myocardial infarction, ischaemia/reperfusion injury, heart failure, aortic aneurysm and ischaemic stroke. Here, we review the molecular mechanism of the activation and effect of the AIM2 inflammasome in cardiovascular disease, revealing new insights into pathogenic factors that may be targeted to treat cardiovascular disease and related dysfunctions.

Measuring the magnetic topological spin structure of light using an anapole probe.

Topological spin structures of light, including the Skyrmion, Meron, and bi-Meron, are intriguing optical phenomena that arise from spin-orbit coupling. They have promising potential applications in nano-metrology, data storage, super-resolved imaging and chiral detection. Aside from the electric part of optical spin, of equal importance is the magnetic part, particularly the H-type electromagnetic modes for which the spin topological properties of the field are dominated by the magnetic field. However, their observation and measurement remains absent and faces difficult challenges. Here, we design a unique type of anapole probe to measure specifically the photonic spin structures dominated by magnetic fields. The probe is composed of an Ag-core and Si-shell nanosphere, which manifests as a pure magnetic dipole with no electric response. The effectiveness of the method was validated by characterizing the magnetic field distributions of various focused vector beams. It was subsequently employed to measure the magnetic topological spin structures, including individual Skyrmions and Meron/Skyrmion lattices for the first time. The proposed method may be a powerful tool to characterize the magnetic properties of optical spin and valuable in advancing spin photonics.

CD34+ cell atlas of main organs implicates its impact on fibrosis.

RATIONALE: CD34+ cells are believed being progenitors that may be used to treat cardiovascular disease. However, the exact identity and the role of CD34+ cells in physiological and pathological conditions remain unclear. METHODS: We performed single-cell RNA sequencing analysis to provide a cell atlas of normal tissue/organ and pathological conditions. Furthermore, a genetic lineage tracing mouse model was used to investigate the role of CD34+ cells in angiogenesis and organ fibrosis. RESULTS: Single-cell RNA sequencing analysis revealed a heterogeneous population of CD34+ cells in both physiological and pathological conditions. Using a genetic lineage tracing mouse model, we showed that CD34+ cells not only acquired endothelial cell fate involved in angiogenesis, but also, CD34+ cells expressing Pi16 may transform into myofibroblast and thus participate in organ fibrosis. CONCLUSION: A heterogeneous CD34+ cells serve as a contributor not only to endothelial regeneration but also a wound healing response that may provide therapeutic insights into fibrosis.

Ischemia-Selective Cardioprotection by Malonate for Ischemia/Reperfusion Injury.

BACKGROUND: Inhibiting SDH (succinate dehydrogenase), with the competitive inhibitor malonate, has shown promise in ameliorating ischemia/reperfusion injury. However, key for translation to the clinic is understanding the mechanism of malonate entry into cells to enable inhibition of SDH, its mitochondrial target, as malonate itself poorly permeates cellular membranes. The possibility of malonate selectively entering the at-risk heart tissue on reperfusion, however, remains unexplored. METHODS: C57BL/6J mice, C2C12 and H9c2 myoblasts, and HeLa cells were used to elucidate the mechanism of selective malonate uptake into the ischemic heart upon reperfusion. Cells were treated with malonate while varying pH or together with transport inhibitors. Mouse hearts were either perfused ex vivo (Langendorff) or subjected to in vivo left anterior descending coronary artery ligation as models of ischemia/reperfusion injury. Succinate and malonate levels were assessed by liquid chromatography-tandem mass spectrometry LC-MS/MS, in vivo by mass spectrometry imaging, and infarct size by TTC (2,3,5-triphenyl-2H-tetrazolium chloride) staining. RESULTS: Malonate was robustly protective against cardiac ischemia/reperfusion injury, but only if administered at reperfusion and not when infused before ischemia. The extent of malonate uptake into the heart was proportional to the duration of ischemia. Malonate entry into cardiomyocytes in vivo and in vitro was dramatically increased at the low pH (≈6.5) associated with ischemia. This increased uptake of malonate was blocked by selective inhibition of MCT1 (monocarboxylate transporter 1). Reperfusion of the ischemic heart region with malonate led to selective SDH inhibition in the at-risk region. Acid-formulation greatly enhances the cardioprotective potency of malonate. CONCLUSIONS: Cardioprotection by malonate is dependent on its entry into cardiomyocytes. This is facilitated by the local decrease in pH that occurs during ischemia, leading to its selective uptake upon reperfusion into the at-risk tissue, via MCT1. Thus, malonate's preferential uptake in reperfused tissue means it is an at-risk tissue-selective drug that protects against cardiac ischemia/reperfusion injury.