Single-cell analysis of ploidy and the transcriptome reveals functional and spatial divergency in murine megakaryopoiesis.

Megakaryocytes (MKs), the platelet progenitor cells, play important roles in hematopoietic stem cell (HSC) maintenance and immunity. However, it is not known whether these diverse programs are executed by a single population or by distinct subsets of cells. Here, we manually isolated primary CD41+ MKs from the bone marrow (BM) of mice and human donors based on ploidy (2N-32N) and performed single-cell RNA sequencing analysis. We found that cellular heterogeneity existed within 3 distinct subpopulations that possess gene signatures related to platelet generation, HSC niche interaction, and inflammatory responses. In situ immunostaining of mouse BM demonstrated that platelet generation and the HSC niche-related MKs were in close physical proximity to blood vessels and HSCs, respectively. Proplatelets, which could give rise to platelets under blood shear forces, were predominantly formed on a platelet generation subset. Remarkably, the inflammatory responses subpopulation, consisting generally of low-ploidy LSP1+ and CD53+ MKs (≤8N), represented ∼5% of total MKs in the BM. These MKs could specifically respond to pathogenic infections in mice. Rapid expansion of this population was accompanied by strong upregulation of a preexisting PU.1- and IRF-8-associated monocytic-like transcriptional program involved in pathogen recognition and clearance as well as antigen presentation. Consistently, isolated primary CD53+ cells were capable of engulfing and digesting bacteria and stimulating T cells in vitro. Together, our findings uncover new molecular, spatial, and functional heterogeneity within MKs in vivo and demonstrate the existence of a specialized MK subpopulation that may act as a new type of immune cell.

Analysis of chemical variations between raw and wine-processed Ligustri Lucidi Fructus by ultra-high-performance liquid chromatography-Q-Exactive Orbitrap/MS combined with multivariate statistical analysis approach.

Ligustri Lucidi Fructus (LLF) is the dried and mature fruit of Ligubtrum lucidum Ait., which has the effect of nourishing the liver and kidney, brightening the eyes and promoting the growth of black hair. Wine-processed LLF is commonly used in traditional Chinese medicine; however, the processing mechanisms are still unclear. Herein, a system data acquisition and mining strategy was designed to investigate the chemical profile differences between the raw and wine-processed LLF, based on high-performance liquid chromatography-Orbitrap high resolution mass spectrometry coupled with multivariate statistical analysis including principal component analysis and partial least square analysis. Afterwars, a total of 55 components were found to be the main contributors to the significant difference between raw and wine-processed LLF by comparison with chromatographic behaviors, intact precursor ions, and characteristic MS fragmentation patterns. In addition, 10 main constituents of raw and wine-processed LLF were simultaneously determined by UHPLC-MS/MS for analyzing the content variations. Some structural transformation mechanisms during wine processing were deduced from the results. The results may provide a scientific foundation for deeply elucidating the wine-processing mechanism of LLF.

Pharmacokinetic comparison of nine bioactive components in rat plasma following oral administration of raw and wine-processed Ligustri Lucidi Fructus by ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry.

An accurate and sensitive ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry method was established and validated for the determination of nine bioactive compounds of Ligustri Lucidi Fructus in rat plasma. Separation was performed on Halo® C18 column with a mobile phase of acetonitrile and 0.1% formic acid in water. The eluate was detected by multiple reaction monitoring scanning operating in the negative ionization mode. This assay method was validated for selectivity, linearity, intra- and interday precision, accuracy, recovery, matrix effect, and stability, and all methodological parameters fulfilled the Food and Drug Administration criteria for bioanalytical validation. The established method was successfully applied to a comparative pharmacokinetic study of raw and wine-processed Ligustri Lucidi Fructus in rats for the first time. It was found that the AUC0-24 and Cmax value of salidroside, hydroxytyrosol, and nuezhenidic acid were increased significantly after processing, while the AUC0-24 and Cmax value of oleoside 11-methyl ester, 1'''-O-ß-d-glucosylformoside, specnuezhenide, G13, oleonuezhenide, and oleanolic acid were decreased, which suggested that processing affects the absorption and bioavailability of Ligustri Lucidi Fructus. The results might be valuable for the clinical reasonable application and understanding the processing mechanism of Ligustri Lucidi Fructus.

UHPLC-MS/MS method for pharmacokinetic and bioavailability determination of five bioactive components in raw and various processed products of Polygala tenuifolia in rat plasma.

CONTEXT: Sibiricose A5 (A5), sibiricose A6 (A6), 3,6'-disinapoyl sucrose (DSS), tenuifoliside A (TFSA) and 3,4,5-trimethoxycinnamic acid (TMCA) are the main active components of Polygala tenuifolia Willd. (Polygalaceae) (PT) that are active against Alzheimer's disease. OBJECTIVE: To compare the pharmacokinetics and bioavailability of five active components in the roots of raw PT (RPT), liquorice-boiled PT (LPT) and honey-stir-baked PT (HPT). MATERIALS AND METHODS: The median lethal dose (LD50) was evaluated through acute toxicity test. The pharmacokinetics of five components after oral administration of extracts of RPT, LPT, HPT (all equivalent to 1.9 g/kg of RPT extract for one dose) and 0.5% CMC-Na solution (control group) were investigated, respectively, in Sprague-Dawley rats (four groups, n = 6) using UHPLC-MS/MS. In addition, the absolute bioavailability of A5, A6, DSS, TFSA and TMCA after oral administration (7.40, 11.60, 16.00, 50.00 and 3.11 mg/kg, respectively) and intravenous injection (1/10 of the corresponding oral dose) in rats (n = 6) was studied. RESULTS: The LD50 of RPT, LPT and HPT was 7.79, 14.55 and 15.99 g/kg, respectively. AUC 0- t of RPT, LPT and HPT were as follows: A5 (433.18 ± 65.48, 680.40 ± 89.21, 552.02 ± 31.10 ng h/mL), A6 (314.55 ± 62.73, 545.76 ± 123.16, 570.06 ± 178.93 ng h/mL) and DSS (100.30 ± 62.44, 232.00 ± 66.08, 197.58 ± 57.37 ng h/mL). The absolute bioavailability of A5, A6, DSS, TFSA and TMCA was 3.25, 2.95, 2.36, 1.17 and 42.91%, respectively. DISCUSSION AND CONCLUSIONS: The pharmacokinetic and bioavailability parameters of each compound can facilitate future clinical studies.

No-Reference Image Quality Assessment Based on Dual-Domain Feature Fusion.

Image quality assessment (IQA) aims to devise computational models to evaluate image quality in a perceptually consistent manner. In this paper, a novel no-reference image quality assessment model based on dual-domain feature fusion is proposed, dubbed as DFF-IQA. Firstly, in the spatial domain, several features about weighted local binary pattern, naturalness and spatial entropy are extracted, where the naturalness features are represented by fitting parameters of the generalized Gaussian distribution. Secondly, in the frequency domain, the features of spectral entropy, oriented energy distribution, and fitting parameters of asymmetrical generalized Gaussian distribution are extracted. Thirdly, the features extracted in the dual-domain are fused to form the quality-aware feature vector. Finally, quality regression process by random forest is conducted to build the relationship between image features and quality score, yielding a measure of image quality. The resulting algorithm is tested on the LIVE database and compared with competing IQA models. Experimental results on the LIVE database indicate that the proposed DFF-IQA method is more consistent with the human visual system than other competing IQA methods.

High-resolution single-cell transcriptomic survey of cardiomyocytes from patients with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a common inherited cardiovascular disease, which can cause heart failure and lead to death. In this study, we performed high-resolution single-cell RNA-sequencing of 2115 individual cardiomyocytes obtained from HCM patients and normal controls. Signature up- and down-regulated genes in HCM were identified by integrative analysis across 37 patients and 41 controls from our data and published human single-cell and single-nucleus RNA-seq datasets, which were further classified into gene modules by single-cell co-expression analysis. Using our high-resolution dataset, we also investigated the heterogeneity among individual cardiomyocytes and revealed five distinct clusters within HCM cardiomyocytes. Interestingly, we showed that some extracellular matrix (ECM) genes were up-regulated in the HCM cardiomyocytes, suggesting that they play a role in cardiac remodelling. Taken together, our study comprehensively profiled the transcriptomic programs of HCM cardiomyocytes and provided insights into molecular mechanisms underlying the pathogenesis of HCM.

Single-cell analysis reveals an Angpt4-initiated EPDC-EC-CM cellular coordination cascade during heart regeneration.

Mammals exhibit limited heart regeneration ability, which can lead to heart failure after myocardial infarction. In contrast, zebrafish exhibit remarkable cardiac regeneration capacity. Several cell types and signaling pathways have been reported to participate in this process. However, a comprehensive analysis of how different cells and signals interact and coordinate to regulate cardiac regeneration is unavailable. We collected major cardiac cell types from zebrafish and performed high-precision single-cell transcriptome analyses during both development and post-injury regeneration. We revealed the cellular heterogeneity as well as the molecular progress of cardiomyocytes during these processes, and identified a subtype of atrial cardiomyocyte exhibiting a stem-like state which may transdifferentiate into ventricular cardiomyocytes during regeneration. Furthermore, we identified a regeneration-induced cell (RIC) population in the epicardium-derived cells (EPDC), and demonstrated Angiopoietin 4 (Angpt4) as a specific regulator of heart regeneration. angpt4 expression is specifically and transiently activated in RIC, which initiates a signaling cascade from EPDC to endocardium through the Tie2-MAPK pathway, and further induces activation of cathepsin K in cardiomyocytes through RA signaling. Loss of angpt4 leads to defects in scar tissue resolution and cardiomyocyte proliferation, while overexpression of angpt4 accelerates regeneration. Furthermore, we found that ANGPT4 could enhance proliferation of neonatal rat cardiomyocytes, and promote cardiac repair in mice after myocardial infarction, indicating that the function of Angpt4 is conserved in mammals. Our study provides a mechanistic understanding of heart regeneration at single-cell precision, identifies Angpt4 as a key regulator of cardiomyocyte proliferation and regeneration, and offers a novel therapeutic target for improved recovery after human heart injuries.

Complete Response With Cetuximab-Based Treatment of Metastatic Colorectal Cancers: Two Case Reports and Literature Review.

Metastases typically develop before diagnosis and during the treatment of colorectal cancers, while patients with metastatic colorectal cancers (mCRCs) currently have a poor prognosis. In terms of surgical approaches, adjuvant therapies, and targeted therapies, the treatment of mCRCs has had numerous recent advances. As a targeted agent widely used in mCRCs, cetuximab-based treatment is still under dispute due to its side effects and unstable effect. We present two mCRC cases treated with cetuximab-based therapy, of which two patients achieved complete response and without recurrence for over 22 and 84 months, respectively. To better understand the drug usage, we also reviewed the recent achievements and usage precautions of cetuximab in mCRCs. Present and many previous observations support that cetuximab might be a referred drug in the first-line chemotherapy of mCRCs with wild-type RAS and BRAF and proficient mismatch repair.

Molecular profiling of human non-small cell lung cancer by single-cell RNA-seq.

BACKGROUND: Lung cancer, one of the most common malignant tumors, exhibits high inter- and intra-tumor heterogeneity which contributes significantly to treatment resistance and failure. Single-cell RNA sequencing (scRNA-seq) has been widely used to dissect the cellular composition and characterize the molecular properties of cancer cells and their tumor microenvironment in lung cancer. However, the transcriptomic heterogeneity among various cancer cells in non-small cell lung cancer (NSCLC) warrants further illustration. METHODS: To comprehensively analyze the molecular heterogeneity of NSCLC, we performed high-precision single-cell RNA-seq analyses on 7364 individual cells from tumor tissues and matched normal tissues from 19 primary lung cancer patients and 1 pulmonary chondroid hamartoma patient. RESULTS: In 6 of 16 patients sequenced, we identified a significant proportion of cancer cells simultaneously expressing classical marker genes for two or even three histologic subtypes of NSCLC-adenocarcinoma (ADC), squamous cell carcinoma (SCC), and neuroendocrine tumor (NET) in the same individual cell, which we defined as mixed-lineage tumor cells; this was verified by both co-immunostaining and RNA in situ hybridization. These data suggest that mixed-lineage tumor cells are highly plastic with mixed features of different types of NSCLC. Both copy number variation (CNV) patterns and mitochondrial mutations clearly showed that the mixed-lineage and single-lineage tumor cells from the same patient had common tumor ancestors rather than different origins. Moreover, we revealed that patients with high mixed-lineage features of different cancer subtypes had worse survival than patients with low mixed-lineage features, indicating that mixed-lineage tumor features were associated with poorer prognosis. In addition, gene signatures specific to mixed-lineage tumor cells were identified, including AKR1B1. Gene knockdown and small molecule inhibition of AKR1B1 can significantly decrease cell proliferation and promote cell apoptosis, suggesting that AKR1B1 plays an important role in tumorigenesis and can serve as a candidate target for tumor therapy of NSCLC patients with mixed-lineage tumor features. CONCLUSIONS: In summary, our work provides novel insights into the tumor heterogeneity of NSCLC in terms of the identification of prevalent mixed-lineage subpopulations of cancer cells with combined signatures of SCC, ADC, and NET and offers clues for potential treatment strategies in these patients.

Single-cell transcriptomic profiling reveals the tumor heterogeneity of small-cell lung cancer.

Small-cell lung cancer (SCLC) is the most aggressive and lethal subtype of lung cancer, for which, better understandings of its biology are urgently needed. Single-cell sequencing technologies provide an opportunity to profile individual cells within the tumor microenvironment (TME) and investigate their roles in tumorigenic processes. Here, we performed high-precision single-cell transcriptomic analysis of ~5000 individual cells from primary tumors (PTs) and matched normal adjacent tissues (NATs) from 11 SCLC patients, including one patient with both PT and relapsed tumor (RT). The comparison revealed an immunosuppressive landscape of human SCLC. Malignant cells in SCLC tumors exhibited diverse states mainly related to the cell cycle, immune, and hypoxic properties. Our data also revealed the intratumor heterogeneity (ITH) of key transcription factors (TFs) in SCLC and related gene expression patterns and functions. The non-neuroendocrine (non-NE) tumors were correlated with increased inflammatory gene signatures and immune cell infiltrates in SCLC, which contributed to better responses to immune checkpoint inhibitors. These findings indicate a significant heterogeneity of human SCLC, and intensive crosstalk between cancer cells and the TME at single-cell resolution, and thus, set the stage for a better understanding of the biology of SCLC as well as for developing new therapeutics for SCLC.

[Prevalence of allergic bronchopulmonary aspergillosis in Chinese patients with bronchial asthma].

OBJECTIVE: To evaluate the frequency of sensitization to Aspergillus antigens and the prevalence of allergic bronchopulmonary aspergillosis (ABPA) in asthmatic patients. METHODS: Two hundred consecutive non-smoking outpatients with asthma (≥ 18 years) underwent skin testing with aeroallergens, peripheral eosinophil counting, measurements of total serum IgE level and specific IgE against Aspergillus fumigatus, radiologic investigations and pulmonary function tests. RESULTS: Eleven patients (5.5%) had a positive skin reactivity to Aspergillus antigens. Five of these 11 patients (45.5%) met the diagnostic criteria of ABPA, an overall prevalence of 2.5% (5/200). There were 2 males and 3 females, aging from 19 to 62 years, with a disease duration from 15 to 40 years. All of the patients had asthmatic symptoms such as cough and wheeze. Moderate to severe obstructive ventilatory defect was found in 4 patients. Total serum IgE levels and specific IgE against Aspergillus fumigates were elevated significantly in all the patients, and elevated eosinophil count was found in 3 patients. Three cases were diagnosed as ABPA-CB because of the presence of central bronchiectasis on HRCT. CONCLUSIONS: The prevalence of ABPA in Chinese patients with asthma was underestimated. Clinical features of ABPA were similar to asthma alone, but with longer duration and more severe lung function defect. Sensitization to Aspergillus, increased eosinophils and total serum IgE levels were important indicators for the diagnosis of ABPA.

A Lung Adenocarcinoma Patient With a Rare EGFR E709_T710delinsD Mutation Showed a Good Response to Afatinib Treatment: A Case Report and Literature Review.

For advanced lung adenocarcinoma patients with common epidermal growth factor receptor (EGFR) mutations (exon 19 deletions or the exon 21 L858R mutation), tyrosine kinase inhibitors (TKIs) are the standard therapies, and achieve favorable responses. However, for the rare EGFR deletion-insertion mutation of exon 18, there is no evidence of the efficacy of EGFR TKIs. Herein, we report a lung adenocarcinoma patient harboring a rare EGFR E709_T710delinsD mutation who was treated with afatinib as the first-line therapy and achieved a progression-free survival of 23 months. After the disease progressed, the patient received almonertinib treatment and exhibited a stable disease. This case indicated that non-small cell lung cancer patients harboring the EGFR E709_T710delinsD mutation could benefit from afatinib treatment, followed with almonertinib treatment, as a potential therapeutic strategy.

Comparative Study on the Chemical Components and Gastrointestinal Function on Rats of the Raw Product and Licorice-Simmered Product of Polygala tenuifolia.

The root of Polygala tenuifolia Willd. (Polygalaceae) (PT) has been listed as a nootropic, anti-inflammatory, and antipsychotic medicine that can cure insomnia. Raw PT (RPT) is toxic and must be processed before clinical use. Licorice-simmered PT (LPT) is one of the most common processed products. We conducted this study in order to investigate the differences in chemical components and gastrointestinal function between RPT and LPT. We used principal component analysis (PCA) and quantitative analysis to study the differences in the chemical components. Animal experiments were conducted to evaluate the effects of PT on the gastrointestinal function of rats before and after simmering. Pathological sections of gastrointestinal tissues, serum hormone levels, and inflammatory cytokines were observed. The PCA results demonstrated that obvious separation was achieved between the RPT and LPT samples. Tenuifoliside B (TFSB), 3,6'-disinapoyl sucrose (DSS), tenuifoliose A (TFOA), tenuifoliose H (TFOH), onjisaponin B (OJB), onjisaponin Z (OJZ), and total saponins levels were decreased after licorice processing, while glomeratose A (GA) and 3,4,5-trimethoxycinnamic acid (TMCA) levels were markedly increased. Compared to the control group, the RPT groups exhibited dramatically lower levels of gastrin (GAS), motilin (MTL), and substance P (SP) and markedly higher levels of vasoactive intestinal peptide (VIP) and somatostatin (SS), but the LPT groups exhibited no significant differences in the above indexes. The levels of interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α) in gastrointestinal tissue were markedly increased in the low RPT (L-RPT), high RPT (H-RPT), and H-LPT groups, showing a certain inflammatory effect, but the inflammatory effect in the L-LPT group was relatively weak. Licorice simmering can effectively reduce the inhibitory effect of RPT on gastrointestinal function in rats and reduce damage to gastrointestinal tissue. This study provides a scientific basis for research on the processing mechanism and clinical application of PT.

Single-cell transcriptome and genome analyses of pituitary neuroendocrine tumors.

BACKGROUND: Pituitary neuroendocrine tumors (PitNETs) are the second most common intracranial tumor. We lacked a comprehensive understanding of the pathogenesis and heterogeneity of these tumors. METHODS: We performed high-precision single-cell RNA sequencing for 2679 individual cells obtained from 23 surgically resected samples of the major subtypes of PitNETs from 21 patients. We also performed single-cell multi-omics sequencing for 238 cells from 5 patients. RESULTS: Unsupervised clustering analysis distinguished all tumor subtypes, which was in accordance with the classification based on immunohistochemistry and provided additional information. We identified 3 normal endocrine cell types: somatotrophs, lactotrophs, and gonadotrophs. Comparisons of tumor and matched normal cells showed that differentially expressed genes of gonadotroph tumors were predominantly downregulated, while those of somatotroph and lactotroph tumors were mainly upregulated. We identified novel tumor-related genes, such as AMIGO2, ZFP36, BTG1, and DLG5. Tumors expressing multiple hormone genes showed little transcriptomic heterogeneity. Furthermore, single-cell multi-omics analysis demonstrated that the tumor had a relatively uniform pattern of genome with slight heterogeneity in copy number variations. CONCLUSIONS: Our single-cell transcriptome and single-cell multi-omics analyses provide novel insights into the characteristics and heterogeneity of these complex neoplasms for the identification of biomarkers and therapeutic targets.

Heterogeneity of glial progenitor cells during the neurogenesis-to-gliogenesis switch in the developing human cerebral cortex.

The heterogeneity and molecular characteristics of progenitor cells, especially glial progenitors, in the developing human cerebral cortex remain elusive. Here, we find that EGFR expression begins to sharply increase after gestational week (GW) 20, which corresponds to the beginning stages of human gliogenesis. In addition, EGFR+ cells are mainly distributed in the germinal zone and frequently colocalize with the stemness marker SOX2 during this period. Then, by performing single-cell RNA sequencing on these EGFR+ cells, we successfully enriched and characterized various glial- and neuronal-lineage progenitor cells and validated their phenotypes in fixed slices. Notably, we identified two subgroups with molecular characteristics similar to those of astrocytes, and the immunostaining results show that these cells are mainly distributed in the outer subventricular zone and might originate from the outer radial glial cells. In short, the EGFR-sorting strategy and molecular signatures in the diverse lineages provide insights into human glial development.

Single-Cell Multiomics Sequencing Reveals Prevalent Genomic Alterations in Tumor Stromal Cells of Human Colorectal Cancer.

To what extent stromal cells in the tumor microenvironment (TME) are transformed by colorectal cancer (CRC) cells is unexplored. To dissect alterations in these non-malignant cells, we performed single-cell multiomics sequencing of 21 patients with microsatellite-stable CRCs and 6 cancer-free, elderly individuals. Surprisingly, somatic copy number alterations (SCNAs) are prevalent in immune cells, fibroblasts, and endothelial cells in both the TME and the normal tissues of each individual. Moreover, the proportions of fibroblasts with SCNAs in tumors (11.1%-47.7%) are much higher than those in adjacent normal tissues (1.1%-10.6%), with gain of chromosome 7 strongly enriched in the TME, clearly indicating clonal expansion. Furthermore, five genes (BGN, RCN3, TAGLN, MYL9, and TPM2) are identified as fibroblast-specific biomarkers of poorer prognosis of CRC. Our study provides evidence and functional relevance of pervasive genomic alterations in the stromal cells of TME in CRC.

Polygalae Radix: A review of its traditional uses, phytochemistry, pharmacology, toxicology, and pharmacokinetics.

Polygalae Radix (Polygalaceae), the dried root of Polygala tenuifolia Willd. and Polygala sibirica L., has been widely used as a medicine for improving cognitive function. In China, Polygalae Radix has been widely used in the treatment of insomnia, forgetfulness, depression, cough, palpitation, and other diseases. More than 140 compounds have been isolated from Polygalae Radix, including saponins, xanthones, oligosaccharide esters, and so on. The compounds and extracts isolated from Polygalae Radix possess wide-ranging pharmacological activities, such as neuroprotective, antidepressant, hypnotic-sedative, anti-inflammatory, antiviral, antitumor, antioxidant, antiaging, and antiarrhythmic effects, among others. The clinical practice of traditional Chinese medicine has proved that raw Polygalae Radix can irritate the throat. Modern studies have found that raw Polygalae Radix exhibits a certain degree of toxicity to the gastrointestinal tract after long-term use or excessive doses and that its main toxic components are saponins. Thus, Polygalae Radix is usually processed, and/or combined with other herbs to reduce gastrointestinal irritation. This review investigated the pharmacokinetics of Polygalae Radix. Future research perspectives and the existing problems of Polygalae Radix were also discussed. This review can broaden the understanding regarding Polygalae Radix and provide references for further research.

Single-cell transcriptomics identifies divergent developmental lineage trajectories during human pituitary development.

The anterior pituitary gland plays a central role in regulating various physiological processes, including body growth, reproduction, metabolism and stress response. Here, we perform single-cell RNA-sequencing (scRNA-seq) of 4113 individual cells from human fetal pituitaries. We characterize divergent developmental trajectories with distinct transitional intermediate states in five hormone-producing cell lineages. Corticotropes exhibit an early intermediate state prior to full differentiation. Three cell types of the PIT-1 lineage (somatotropes, lactotropes and thyrotropes) segregate from a common progenitor coexpressing lineage-specific transcription factors of different sublineages. Gonadotropes experience two multistep developmental trajectories. Furthermore, we identify a fetal gonadotrope cell subtype expressing the primate-specific hormone chorionic gonadotropin. We also characterize the cellular heterogeneity of pituitary stem cells and identify a hybrid epithelial/mesenchymal state and an early-to-late state transition. Here, our results provide insights into the transcriptional landscape of human pituitary development, defining distinct cell substates and subtypes and illustrating transcription factor dynamics during cell fate commitment.

Single-Cell Transcriptome Analysis Maps the Developmental Track of the Human Heart.

The heart is the central organ of the circulatory system, and its proper development is vital for maintaining human life. Here, we used single-cell RNA sequencing to profile the gene expression landscapes of ∼4,000 cardiac cells from human embryos and identified four major types of cells: cardiomyocytes (CMs), cardiac fibroblasts, endothelial cells (ECs), and valvar interstitial cells (VICs). Atrial and ventricular CMs acquired distinct features early in heart development. Furthermore, both CMs and fibroblasts show stepwise changes in gene expression. As development proceeds, VICs may be involved in the remodeling phase, and ECs display location-specific characteristics. Finally, we compared gene expression profiles between humans and mice and identified a series of unique features of human heart development. Our study lays the groundwork for elucidating the mechanisms of in vivo human cardiac development and provides potential clues to understand cardiac regeneration.

Dissecting the Global Dynamic Molecular Profiles of Human Fetal Kidney Development by Single-Cell RNA Sequencing.

Healthy renal function depends on normal nephrogenesis during embryonic development. However, a comprehensive gene expression profile of human fetal kidney development remains largely unexplored. Here, using a single-cell RNA-sequencing technique, we analyzed >3,000 human fetal renal cells spanning 4 months of development in utero. Unsupervised analysis identified two progenitor subtypes during cap mesenchyme development, suggesting a mechanism for sustaining their progenitor states. Furthermore, we identified critical transcriptional regulators and signaling pathways involved in the segmentation of nephron tubules. We explored the development of the highly heterogeneous collecting duct epithelia and dissected the metabolic gene repertoire and the extracellular matrix composition of the glomerular mesangium. The results provide insights on the molecular basis and regulatory events in human renal development. Moreover, the cell-type-specific expression features of causal genes in congenital renal diseases may be helpful in the treatment of these diseases.