Alzheimer's disease risk allele of PICALM causes detrimental lipid droplets in microglia.

Despite genome-wide association studies of late-onset Alzheimer's disease (LOAD) having identified many genetic risk loci 1-6, the underlying disease mechanisms remain largely unknown. Determining causal disease variants and their LOAD-relevant cellular phenotypes has been a challenge. Leveraging our approach for identifying functional GWAS risk variants showing allele-specific open chromatin (ASoC) 7, we systematically identified putative causal LOAD risk variants in human induced pluripotent stem cells (iPSC)-derived neurons, astrocytes, and microglia (MG) and linked PICALM risk allele to a previously unappreciated MG-specific role of PICALM in lipid droplet (LD) accumulation. ASoC mapping uncovered functional risk variants for 26 LOAD risk loci, mostly MG-specific. At the MG-specific PICALM locus, the LOAD risk allele of rs10792832 reduced transcription factor (PU.1) binding and PICALM expression, impairing the uptake of amyloid beta (Aß) and myelin debris. Interestingly, MG with PICALM risk allele showed transcriptional enrichment of pathways for cholesterol synthesis and LD formation. Genetic and pharmacological perturbations of MG further established a causal link between the reduced PICALM expression, LD accumulation, and phagocytosis deficits. Our work elucidates the selective LOAD vulnerability in microglia for the PICALM locus through detrimental LD accumulation, providing a neurobiological basis that can be exploited for developing novel clinical interventions.

Association between oxidative balance score and resistant hypertension and arterial stiffness among US adults: A population-based study.

BACKGROUND AND AIMS: Prior studies have established the correlation between oxidative balance score (OBS) and hypertension (HTN). While the association between OBS and resistant hypertension (RHT) as well as arterial stiffness among individuals with hypertension remains undisclosed. METHODS AND RESULTS: In this study, total of 15,910 adults diagnosed with hypertension were enrolled from NHANES 2001-2018. OBS was calculated and categorized into quartiles. Weighted regression model, stratified analyses and restricted cubic spline (RCS) were employed to evaluate the association between OBS and RHT, major adverse cardiovascular events (MACEs) and arterial stiffness in individuals with hypertension. Among enrolled participants, high OBS quartiles consistently demonstrated a negative association with resistant hypertension across all models (all p < 0.05), indicating robust stability. Compared with the lowest OBS quartile, the risk of resistant hypertension in the highest OBS quartile was decreased by 30.8% (95%CI 0.471-0.995, p = 0.049). After dividing OBS into dietary OBS and lifestyle OBS, a significant inverse association with lifestyle OBS and RHT was observed. With regard to MACEs, the inverse association was also found in participants with high OBS. Besides, the potential relation between OBS and arterial stiffness was explored and we found OBS was significantly associated with decreased arterial stiffness (ß for ePWV, -0.014; 95%CI -0.026 to -0.001; p = 0.032). RCS analysis confirmed a nonlinear association between OBS and RHT, MACEs, cardiovascular death and nonfatal MI among participants with hypertension. CONCLUSION: Elevated OBS was negatively associated with the risk of RHT and arterial stiffness among US adults with hypertension.

Neutrophil extracellular traps promoting fibroblast activation and aggravating limb ischemia through Wnt5a pathway.

Although the formation of NETs contributes to cancer cell invasion and distant metastasis, its role in the pathological progression of limb ischemia remains unknown. This study investigated the functional significance of NETs in cell-cell crosstalk during limb ischemia. The changes of cell subsets in lower limb ischemia samples were detected by single-cell RNA sequencing. The expression of neutrophil extracellular traps (NETs) related markers in lower limb ischemia samples was detected by immunohistochemistry and Western blotting. The signaling pathway of NETs activation in fibroblasts was verified by immunofluorescence, PCR and Western blotting. Through single-cell RNA sequencing (scRNA-seq), we identified 9 distinct cell clusters, with significantly upregulated activation levels in fibroblasts and neutrophils and phenotypic transformation of smooth muscle cells (SMCs) into a proliferative state in ischemic tissue. At the same time, the interaction between fibroblasts and smooth muscle cells was significantly enhanced in ischemic tissue. NETs levels rise and fibroblast activation is induced in ischemic conditions. Mechanistically, activated fibroblasts promote smooth muscle cell proliferation through the Wnt5a pathway. In ischemic mice, inhibition of Wnt5a mitigated vascular remodeling and subsequent ischemia. These findings highlighting the role of cell-cell crosstalk in ischemia and vascular remodeling. We found that the NETs-initiated fibroblast-SMC interaction is a critical regulator of limb ischemia via Wnt5a pathway, a potential therapeutic target for the treatment.

Correlation of dietary inflammation index and dietary pattern with mild cognitive impairment in patients with type 2 diabetes.

OBJECTIVE: We aimed to determine the dietary patterns associated with mild cognitive impairment (MCI) in type 2 diabetes (T2DM) and the correlation of dietary inflammatory index (DII) with MCI. METHODS: The Montreal Cognitive Assessment (MoCA) was used to assess cognitive function. A semi-quantitative food frequency questionnaire was used to collect dietary data and calculate DII. Dietary patterns were determined by reduced-rank regression (RRR), grouping dietary pattern scores and DII into quartiles, with logistic regression for correlation analysis. Dose-response relationships between dietary pattern scores, DII and diabetic MCI were explored using restricted cubic splines (RCS). A mediation analysis was performed to investigate whether DII mediates the association between dietary patterns and MCI. RESULTS: In the "Mediterranean-style dietary pattern", the multivariable-adjusted odds ratio of having MCI was 0.37 (95% CI: 0.20-0.68; p for trend=0.002) in the highest versus lowest quartiles of the dietary score. In the "high-meat and low-vegetable pattern", the multivariable-adjusted odds ratio of having MCI was 6.84 (95% CI: 3.58-13.10; p for trend<0.001) in the highest versus lowest quartiles of the dietary score. In the "Western-style dietary pattern", the multivariable-adjusted odds ratio of having MCI was 2.48 (95% CI: 1.38-4.46; p for trend=0.001). The multivariable-adjusted odds ratio of having MCI was 3.99 (95% CI: 2.14-7.42; p for trend<0.001) in the highest versus lowest quartiles of DII. There is a non-linear dose-response relationship between the "high-meat and low-vegetable pattern" score and the prevalence of MCI, as well as the DII and the prevalence of MCI. The DII partially mediated the impact of the "Mediterranean-style dietary pattern" and the "high-meat and low-vegetable pattern" on MCI. CONCLUSION: In T2DM patients, greater adherence to the "Mediterranean-style dietary pattern" is associated with a lower probability of having MCI. However, excessive consumption of meat, especially red meat and processed meat, combined with a lack of vegetable intake, is associated with a higher probability of having MCI. Greater adherence to the "Western-style dietary pattern" is associated with a higher probability of having MCI. In addition, a pro-inflammatory diet is associated with a higher probability of having MCI, and DII partially mediates the impact of dietary patterns on MCI.

Changes in posterior corneal elevation after small incision lenticule extraction for different myopic diopters.

AIM: To study the changes and effect factors of posterior corneal surface after small incision lenticule extraction (SMILE) with different myopic diopters. METHODS: Ninety eyes of 90 patients who underwent SMILE were included in this retrospective study. Patients were allocated into three groups based on the preoperative spherical equivalent (SE): low myopia (SE≥-3.00 D), moderate myopia (-3.00 D>SE>-6.00 D) and high myopia (SE≤-6.00 D). Posterior corneal surfaces were measured by a Scheimpflug camera preoperatively and different postoperative times (1wk, 1, 3, 6mo, and 1y). Posterior mean elevation (PME) at 25 predetermined points of 3 concentric circles (2-, 4-, and 6-mm diameter) above the best fit sphere was analyzed. RESULTS: All surgeries were completed uneventfully and no ectasia was found through the observation. The difference of myopia group was significant at the 2-mm ring at 1 and 3mo postoperatively (1mo: P=0.017; 3mo: P=0.018). The effect of time on ΔPME was statistically significant (2-mm ring: P=0.001; 4-mm ring: P<0.001; 6-mm ring: P<0.001). The effect of different corneal locations on ΔPME was significant except 1wk postoperatively (1mo: P=0.000; 3mo: P=0.000; 6mo: P=0.001; 1y: P=0.001). Posterior corneal stability was linearly correlated with SE, central corneal thickness, ablation depth, residual bed thickness, percent ablation depth and percent stromal bed thickness. CONCLUSION: The posterior corneal surface changes dynamically after SMILE. No protrusion is observed on the posterior corneal surface in patients with different degrees of myopia within one year after surgery. SMILE has good stability, accuracy, safety and predictability.

Eucommia granules activate Wnt/ß-catenin pathway, and improve oxidative stress, inflammation, and endothelial injury in preeclampsia rats.

PURPOSE: Pre-eclampsia (PE) is a pregnancy-related complication. Eucommia is effective in the treatment of hypertensive disorders in pregnancy, but the specific effects and possible mechanisms of Eucommia granules (EG) in PE remain unknown. The aim of this study was to investigate the effects and possible mechanisms of EG in PE rats. METHODS: Pregnant Sprague Dawley rats were divided into five groups (n = 6): the control group, the model group, the low-dose group, the medium-dose group, and the high-dose group of EG. The PE model was established by subcutaneous injection of levonitroarginine methyl ester. Saline was given to the blank and model groups, and the Eucommia granules were given by gavage to the remaining groups. Blood pressure and urinary protein were detected. The body length and weight of the pups and the weight of the placenta were recorded. Superoxide dismutase (SOD) activity and levels of malondialdehyde (MDA), placental growth factor (PIGF), and soluble vascular endothelial growth factor receptor-1 (sFIt-1) were measured in the placenta. Pathological changes were observed by hematoxylin-eosin staining. Wnt/ß-catenin pathway-related protein expression was detected using Western blot. RESULTS: Compared with the model group, the PE rats treated with EG had lower blood pressure and urinary protein. The length and weight of the pups and placental weight were increased. Inflammation and necrosis in the placental tissue was improved. SOD level increased, MDA content and sFIt-1/PIGF ratio decreased, and Wnt/ß-catenin pathway-related protein expression level increased. Moreover, the results of EG on PE rats increased with higher doses of EG. CONCLUSIONS: EG may activate the Wnt/ß-catenin pathway and inhibit oxidative stress, inflammation, and vascular endothelial injury in PE rats, thereby improving the perinatal prognosis of preeclamptic rats. EG may inhibit oxidative stress, inflammation, and vascular endothelial injury through activation of the Wnt/ß-catenin pathway in preeclampsia rats, thereby improving perinatal outcomes in PE rats.

Fibroblasts facilitate lymphatic vessel formation in transplanted heart.

Rationale: Lymphangiogenesis plays a critical role in the transplanted heart. The remodeling of lymphatics in the transplanted heart and the source of newly formed lymphatic vessels are still controversial, especially the mechanism of lymphangiogenesis remains limited. Methods: Heart transplantation was performed among BALB/c, C57BL/6J, Cag-Cre, Lyve1-CreERT2;Rosa26-tdTomato and Postn(2A-CreERT2-wpre-pA)1;Rosa26-DTA mice. scRNA-seq, Elisa assay, Western blotting, Q-PCR and immunohistochemical staining were used to identify the cells and cell-cell communications of allograft heart. Cell depletion was applied to in vivo and in vitro experiments. Whole-mount staining and three-dimensional reconstruction depicted the cell distribution within transparent transplanted heart. Results: Genetic lineage tracing mice and scRNA-seq analysis have revealed that these newly formed lymphatic vessels mainly originate from recipient LYVE1+ cells. It was found that LECs primarily interact with activated fibroblasts. Inhibition of lymphatic vessel formation using a VEGFR3 inhibitor resulted in a decreased survival time of transplanted hearts. Furthermore, when activated fibroblasts were ablated in transplanted hearts, there was a significant suppression of lymphatic vessel generation, leading to earlier graft failure. Additional investigations have shown that activated fibroblasts promote tube formation of LECs primarily through the activation of various signaling pathways, including VEGFD/VEGFR3, MDK/NCL, and SEMA3C/NRP2. Interestingly, knockdown of VEGFD and MDK in activated fibroblasts impaired cardiac lymphangiogenesis after heart transplantation. Conclusions: Our study indicates that cardiac lymphangiogenesis primarily originates from recipient cells, and activated fibroblasts play a crucial role in facilitating the generation of lymphatic vessels after heart transplantation. These findings provide valuable insights into potential therapeutic targets for enhancing graft survival.

Associations between one-carbon metabolism and valproic acid-induced liver dysfunction in epileptic patients.

Valproic acid (VPA) has been widely used as an antiepileptic drug for decades. Although VPA is effective and well-tolerated, long-term VPA treatment is usually associated with hepatotoxicity. However, the underlying mechanisms of VPA-caused hepatotoxicity remain unclear. In this study, a total of 157 pediatric patients with epilepsy were recruited and divided into normal liver function (NLF, 112 subjects) group and abnormal liver function (ABLF, 45 subjects) group. We observed that MTHFR A1298C and MTHFR C677T variants may be linked to VPA-induced liver dysfunction (p = 0.001; p = 0.023, respectively). We also found that the MTHFR A1298C polymorphism was associated with a higher serum Hcy level (p = 0.001) and a lower FA level (p = 0.001). Moreover, the serum Hcy levels was strongly correlated with the GSH and TBARS concentrations (r = -0.6065, P < 0.001; r = 0.6564, P < 0.001, respectively). Furthermore, logistic analysis indicated that MTHFR A1298C/C677T polymorphisms and increased Hcy concentrations may be risk factors for VPA-induced liver dysfunction. These results suggested that individual susceptibility to VPA-induced liver dysfunction may result from MTHFR A1298C/C677T polymorphisms and increased Hcy levels. This study may be helpful for the prevention and guidance of VPA-induced liver dysfunction.

Intra-nanoparticle plasmonic nanogap based spatial-confinement SERS analysis of polypeptides.

Sensing and characterizing water-soluble polypeptides are essential in various biological applications. However, detecting polypeptides using Surface-Enhanced Raman Scattering (SERS) remains a challenge due to the dominance of aromatic amino acid residues and backbones in the signal, which hinders the detection of non-aromatic amino acid residues. Herein, intra-nanoparticle plasmonic nanogap were designed by etching the Ag shell in Au@AgNPs (i.e., obtaining AuAg cores) with chlorauric acid under mild conditions, at the same time forming the outermost Au shell and the void between the AuAg cores and the Au shell (AuAg@void@Au). By varying the Ag to added chloroauric acid molar ratios, we pioneered a simple, controllable, and general synthetic strategy to form interlayer-free nanoparticles with tunable Au shell thickness, achieving precise regulation of electric field enhancement within the intra-nanogap. As validation, two polypeptide molecules, bacitracin and insulin B, were successfully synchronously encapsulated and spatial-confined in the intra-nanogap for sensing. Compared with concentrated 50 nm AuNPs and Au@AgNPs as SERS substrates, our simultaneous detection method improved the sensitivity of the assay while benefiting to obtain more comprehensive characteristic peaks of polypeptides. The synthetic strategy of confining analytes while fabricating plasmonic nanostructures enables the diffusion of target molecules into the nanogap in a highly specific and sensitive manner, providing the majority of the functionality required to achieve peptide detection or sequencing without the hassle of labeling.

RNA-seq based transcriptomic map reveals multiple pathways of necroptosis in treating myocardial ischemia reperfusion injury.

Necroptosis has been shown to contribute to myocardial ischemia reperfusion injury (MIRI). This study aims to gain new insights into the signaling pathway of necroptosis in rat MIRI using RNA sequencing. MIRI was induced in male rats by ligating the left anterior descending coronary artery for 30 min, followed by reperfusion for 120 min. RNA sequencing was performed to obtain mRNA profiles of MIRI group and MIRI group treated with necrostatin-1 (Nec-1,an inhibitor of necroptosis). Differentially expressed genes (DEGs) were then identified. The DEGs were prominently enriched in the TNF-α signaling pathway, the MAPK signaling pathway and cytokine-cytokine receptor pathways. The majority of the results were associated with genes like Thumpd3,Egr2,Dot1l,Cyp1a1,Dbnl,which primarily regulate inflammatory response and apoptosis, particularly in myocardium. The above results suggested that Nec-1 might be involved in the regulation of necroptosis and the inflammatory response through the above-mentioned genes.

Freeze-thaw stability of transglutaminase-induced soy protein-maltose emulsion gel: Focusing on morphology, texture properties, and rheological characteristics.

In this study, soy protein isolate (SPI) and maltose (M) were employed as materials for the synthesis of a covalent compound denoted as SPI-M. The emulsion gel was prepared by transglutaminase (TGase) as catalyst, and its freeze-thaw stability was investigated. The occurrence of Maillard reaction was substantiated through SDS-PAGE. The analysis of spectroscopy showed that the structure of the modified protein was more stretched, changed in the direction of freeze-thaw stability. After three freeze-thaw cycles (FTC), it was observed that the water holding capacity of SPI-M, SPI/M mixture (SPI+M) and SPI emulsion gels exhibited reductions of 8.49 %, 16.85 %, and 20.26 %, respectively. Moreover, the soluble protein content also diminished by 13.92 %, 23.43 %, and 35.31 %, respectively. In comparison to unmodified SPI, SPI-M exhibited increase in gel hardness by 160 %, while elasticity, viscosity, chewability, and cohesion demonstrated reductions of 17.7 %, 23.3 %, 33.3 %, and 6.76 %, respectively. Concurrently, the SPI-M emulsion gel exhibited the most rapid gel formation kinetics. After FTCs, the gel elastic modulus (G') and viscosity modulus (G″) of SPI-M emulsion were the largest. DSC analysis underscored the more compact structure and heightened thermal stability of the SPI-M emulsion gel. SEM demonstrated that the SPI-M emulsion gel suffered the least damage following FTCs.

Insulin resistance is associated with the presence and severity of retinopathy in patients with type 2 diabetes.

BACKGROUND: To assess the relationship between novel insulin resistance (IR) indices and the presence and severity of diabetic retinopathy (DR) in patients with type 2 diabetes. METHODS: This is a cross-sectional study involving 2211 patients. The study outcomes were DR events. The study exposures were IR indices including estimated glucose disposal rate (eGDR), natural logarithm of glucose disposal rate (lnGDR), metabolic insulin resistance score (METS-IR), triglyceride glucose index-body mass index (TyG-BMI), triglyceride glucose index-waist-to-hip ratio (TyG-WHR), and triglyceride/high-density lipoprotein cholesterol(TG/HDL-c ratio). We used binary and multivariate ordered logistic regression models to estimate the association between different IR indices and the presence and severity of DR. Subject work characteristic curves were used to assess the predictive power of different IR indices for DR. RESULTS: DR was present in 25.4% of participants. After adjusting for all covariates, per standard deviation (SD) increases in eGDR (ratio [OR] 0.38 [95% CI 0.32-0.44]), lnGDR (0.34 [0.27-0.42]) were negatively associated with the presence of DR. In contrast, per SD increases in METS-IR (1.97 [1.70-2.28]), TyG-BMI (1.94 [1.68-2.25]), TyG-WHR (2.34 [2.01-2.72]) and TG/HDL-c ratio (1.21 [1.08-1.36]) were positively associated with the presence of DR. eGDR was strongly associated with severity of DR. Of all variables, eGDR had the strongest diagnostic value for DR (AUC = 0.757). CONCLUSIONS: Of the six IR indices, eGDR was significantly associated with the presence and severity of DR in patients with type 2 diabetes. eGDR has a good predictive value for DR. Thus, eGDR maybe a stronger marker of DR.

Moisture-Electric-Moisture-Sensitive Heterostructure Triggered Proton Hopping for Quality-Enhancing Moist-Electric Generator.

Moisture-enabled electricity (ME) is a method of converting the potential energy of water in the external environment into electrical energy through the interaction of functional materials with water molecules and can be directly applied to energy harvesting and signal expression. However, ME can be unreliable in numerous applications due to its sluggish response to moisture, thus sacrificing the value of fast energy harvesting and highly accurate information representation. Here, by constructing a moisture-electric-moisture-sensitive (ME-MS) heterostructure, we develop an efficient ME generator with ultra-fast electric response to moisture achieved by triggering Grotthuss protons hopping in the sensitized ZnO, which modulates the heterostructure built-in interfacial potential, enables quick response (0.435 s), an unprecedented ultra-fast response rate of 972.4 mV s-1, and a durable electrical signal output for 8 h without any attenuation. Our research provides an efficient way to generate electricity and important insight for a deeper understanding of the mechanisms of moisture-generated carrier migration in ME generator, which has a more comprehensive working scene and can serve as a typical model for human health monitoring and smart medical electronics design.

The halogen substitution strategy of inorganic skeletons triggers dielectric and band gap regulation of hybrid perovskites.

Organic-inorganic hybrid perovskites (OIHPs) with dielectric switching functions have aroused comprehensive scientific interest, benefitting from their promising applications in sensors and information storage. However, to date, most of these materials discovered thus far possess a single function and are limited in their applicability, failing to meet the requirements of diverse applications. Moreover, the discovery of these materials has been largely serendipitous. Building multifunctional OIHPs with dielectric switching and semiconductors remains a daunting task. In this context, by introducing [C7H16N]+ as cations and in combination with lead halide with semiconducting properties, two OIHPs [C7H16N]PbI3 (1) and [C7H16N]PbBr3 (2) ([C7H16N]+ = (cyclopropylmethyl) trimethylammonium) have been successfully designed. They have dielectric switching properties close to 253 and 279 K and semiconducting behavior with band gaps of 2.67 and 3.22 eV. The phase transition temperature increased by 26 K through halogen substitution. In summary, our findings in this study provide insights into the application of the halogen substitution regulation strategy and open up new possibilities for designing perovskite semiconductors with dielectric switching functionality.

Serpin-1a and serpin-6 regulate the Toll pathway immune homeostasis by synergistically inhibiting the Spätzle-processing enzyme CLIP2 in silkworm, Bombyx mori.

The Toll receptor signaling pathway is an important innate immune response of insects to pathogen infection; its extracellular signal transduction involves serine protease cascade activation. However, excessive or constitutive activation of the Toll pathway can be detrimental. Hence, the balance between activation and inhibition of the extracellular protease cascade must be tightly regulated to achieve favorable outcomes. Previous studies have shown that serpins-serine protease inhibitors-negatively regulate insect innate immunity by inhibiting extracellular protease cascade signaling. Although the roles of serpins in insect innate immunity are well described, the physiological mechanisms underlying their synergistic effects remain poorly understand. Here, we characterize the molecular mechanism by which serpin-1a and serpin-6 synergistically maintain immune homeostasis of the silkworm Toll pathway under physiological and pathological conditions. Through in vitro biochemical assays and in vivo bioassays, we demonstrate that clip-domain serine protease 2 (CLIP2), as the Toll cascade-activating terminal protease, is responsible for processing proSpätzle1 to induce the expression of antimicrobial peptides. Further biochemical and genetic analyses indicate that constitutively expressed serpin-1a and inducible serpin-6 synergistically target CLIP2 to maintain homeostasis of the silkworm Toll pathway under physiological and pathological conditions. Taken together, this study provides new insights into the precise regulation of Toll cascade activation signals in insect innate immune responses and highlights the importance and complexity of insect immune homeostasis regulation.

Role of IL-34 and its receptors in inflammatory diseases.

In recent years, IL-34 has been widely discussed as a novel cytokine. IL-34 is a pro-inflammatory cytokine binding four distinct receptors, namely CSF-1R, syndecan-1, PTP-ζ and TREM2. Previous studies have shown that IL-34 and its receptors play important roles in the development and progression of various inflammatory diseases. Therefore, IL-34 has the potential to be a biomarker and therapeutic target for inflammatory diseases. However, further study is still needed to identify the specific mechanism through which IL-34 contributes to illness. In this article, we review the recent advances in the biological roles of IL-34 and its receptors as well as their roles in the development and therapeutic application of inflammatory diseases.

Multiple genes in a single GWAS risk locus synergistically mediate aberrant synaptic development and function in human neurons.

The mechanistic tie between genome-wide association study (GWAS)-implicated risk variants and disease-relevant cellular phenotypes remains largely unknown. Here, using human induced pluripotent stem cell (hiPSC)-derived neurons as a neurodevelopmental model, we identify multiple schizophrenia (SZ) risk variants that display allele-specific open chromatin (ASoC) and are likely to be functional. Editing the strongest ASoC SNP, rs2027349, near vacuolar protein sorting 45 homolog (VPS45) alters the expression of VPS45, lncRNA AC244033.2, and a distal gene, C1orf54. Notably, the transcriptomic changes in neurons are associated with SZ and other neuropsychiatric disorders. Neurons carrying the risk allele exhibit increased dendritic complexity and hyperactivity. Interestingly, individual/combinatorial gene knockdown shows that these genes alter cellular phenotypes in a non-additive synergistic manner. Our study reveals that multiple genes at a single GWAS risk locus mediate a compound effect on neural function, providing a mechanistic link between a non-coding risk variant and disease-related cellular phenotypes.

Host CD34+ cells are replacing donor endothelium of transplanted heart.

BACKGROUND: Endothelium dysfunction is a central problem for early rejection due to the host alloimmune response and the late status of arteriosclerosis in heart transplantation. However, reliable pieces of evidence are still limited concerning the source of the regenerated endothelium within the transplanted heart. METHODS: We analyzed single-cell RNA sequencing data and constructed an inducible lineage tracing mouse, combined heart transplantation with bone marrow transplantation and a parabiosis model, cellular components, and endothelial cell populations in cardiac graft lesions. RESULTS: Our single-cell RNA sequencing analysis of a transplanted heart allowed for the establishment of an endothelial cell atlas with a heterogeneous population, including arterial, venous, capillary, and lymphatic endothelial cells. Along with genetic cell lineage tracing, we demonstrated that the donor cells were mostly replaced by recipient cells in the cardiac allograft, up to 83.29% 2 weeks after transplantation. Furthermore, recipient nonbone marrow CD34+ endothelial progenitors contributed significantly to extracellular matrix organization and immune regulation, with higher apoptotic ability in the transplanted hearts. Mechanistically, peripheral blood-derived human endothelial progenitor cells differentiate into endocardial cells via Vascular endothelial growth factor receptor-mediated pathways. Host circulating CD34+ endothelial progenitors could repair the damaged donor endothelium presumably through CCL3-CCR5 chemotaxis. Partial depletion of host CD34+ cells resulted in delayed endothelial regeneration. CONCLUSIONS: We created an annotated fate map of endothelial cells in cardiac allografts, indicating how recipient CD34+ cells could replace the donor endothelium via chemokine CCL3-CCR5 interactions. The mechanisms we discovered could have a potential therapeutic effect on the long-term outcomes of heart transplantation.

Single-cell genomics improves the discovery of risk variants and genes of atrial fibrillation.

Genome-wide association studies (GWAS) have linked hundreds of loci to cardiac diseases. However, in most loci the causal variants and their target genes remain unknown. We developed a combined experimental and analytical approach that integrates single cell epigenomics with GWAS to prioritize risk variants and genes. We profiled accessible chromatin in single cells obtained from human hearts and leveraged the data to study genetics of Atrial Fibrillation (AF), the most common cardiac arrhythmia. Enrichment analysis of AF risk variants using cell-type-resolved open chromatin regions (OCRs) implicated cardiomyocytes as the main mediator of AF risk. We then performed statistical fine-mapping, leveraging the information in OCRs, and identified putative causal variants in 122 AF-associated loci. Taking advantage of the fine-mapping results, our novel statistical procedure for gene discovery prioritized 46 high-confidence risk genes, highlighting transcription factors and signal transduction pathways important for heart development. In summary, our analysis provides a comprehensive map of AF risk variants and genes, and a general framework to integrate single-cell genomics with genetic studies of complex traits.