E3 ubiquitin ligase WWP2 as a promising therapeutic target for diverse human diseases.

Mammalian E3 ubiquitin ligases have emerged in recent years as critical regulators of cellular homeostasis due to their roles in targeting substrate proteins for ubiquitination and triggering subsequent downstream signals. In this review, we describe the multiple roles of WWP2, an E3 ubiquitin ligase with unique and important functions in regulating a wide range of biological processes, including DNA repair, gene expression, signal transduction, and cell-fate decisions. As such, WWP2 has evolved to play a key role in normal physiology and diseases, such as tumorigenesis, skeletal development and diseases, immune regulation, cardiovascular disease, and others. We attempt to provide an overview of the biochemical, physiological, and pathophysiological roles of WWP2, as well as open questions for future research, particularly in the context of putative therapeutic opportunities.

Combining physical mechanisms and deep learning models for hourly surface ozone retrieval in China.

As surface ozone (O3) gains increasing attention, there is an urgent need for high temporal resolution and accurate O3 monitoring. By taking advantage of the progress in artificial intelligence, deep learning models have been applied to satellite based O3 retrieval. However, the underlying physical mechanisms that influence surface O3 into model construction have rarely been considered. To overcome this issue, we considered the physical mechanisms influencing surface O3 and used them to select relevant variable features for developing a novel deep learning model. We used a wide and deep model architecture to account for linear and non-linear relationships between the variables and surface O3. Using the developed model, we performed hourly inversions of surface O3 retrieval over China from 2017 to 2019 (9:00-17:00, local time). The validation results based on sample-based (site-based) methods yielded an R2 of 0.94 (0.86) and an RMSE of 12.79 (19.13) µg/m3, indicating the accuracy of the models. The average surface O3 concentrations in China in 2017, 2018, and 2019 were 82, 78, and 87 µg/m3, respectively. There was a diurnal pattern in surface O3 in China, with levels rising significantly from 55 µg/m3 at 9:00 a.m. to 96 µg/m3 at 15:00. Between 15:00 and 16:00, the O3 concentration remained stable at 95 µg/m3 and decreased slightly thereafter (16:00-17:00). The results of this study contribute to a deeper understanding of the physical mechanisms of ozone and facilitate further studies on ozone monitoring, thereby enhancing our understanding of the spatiotemporal characteristics of ozone.

Bioactive compound composition and cellular antioxidant activity of fig (Ficus carica L.).

BACKGROUND: Fig (Ficus carica L.) fruit is consumed worldwide as a functional food. It contains phytochemicals that have been related to health benefits. However, the characteristic chemicals remain unclear. In this work, phytochemicals were prepared from figus by ultrasound-assisted extraction under optimized conditions. The chemical composition of fig fruit and leaves was characterized by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). RESULTS: One hundred and fifty-seven compounds were identified, including 58 flavonoids, 29 coumarins, 19 acids, 15 terpenoids, 11 alkaloids, and 25 other compounds. The mass spectrum (MS) fragmentation pathways of representative chemicals were elucidated. Flavonoid glycosides and prenylated flavonoids were mainly present in fig fruit, whereas coumarins were abundant in leaves. Both fig fruit and leaf extracts showed good cellular antioxidant activity. CONCLUSION: The full phytochemical profile of fig was revealed by UPLC-MS/MS. Prenylated flavonoids and prenylated coumarins were the characteristic phytochemicals. These data provided useful information for the extensive utilization of fig fruit in functional food. © 2023 Society of Chemical Industry.

New insights of flavonoid glycosidases and their application in food industry.

Flavonoids are significant natural nutraceuticals and a key component of dietary supplements. Given that flavonoid glycosides are more plentiful in nature and less beneficial to human health than their aglycone counterparts, they serve as potential precursors for flavonoid production. Glycosidases have shown substantial potential within the food industry, particularly in enhancing the organoleptic properties of juice, wine, and tea. When applied to food resources, glycosidases can amplify their biological activities, thereby improving the performance of functional foods. This review provides up-to-date information on flavonoid glycosidases, including their catalytic mechanisms, biochemical properties, and natural sources, as well as their applications within the food industry. The use of flavonoid glycosidases in improving food quality is also reviewed.

Assessment of the Biocontrol Potential of Bacillus velezensis WL-23 against Kiwifruit Canker Caused by Pseudomonas syringae pv. actinidiae.

Kiwifruit canker disease, caused by Pseudomonas syringae pv. actinidiae (Psa), is the main threat to kiwifruit production worldwide. Currently, there is no safe and effective disease prevention method; therefore, biological control technologies are being explored for Psa. In this study, Bacillus velezensis WL-23 was isolated from the leaf microbial community of kiwifruit and used to control kiwifruit cankers. Indoor confrontation experiments showed that both WL-23 and its aseptic filtrate had excellent inhibitory activity against the main fungal and bacterial pathogens of kiwifruit. Changes in OD600, relative conductivity, alkaline proteinase, and nucleic acid content were recorded during Psa growth after treatment with the aseptic filtrate, showing that Psa proliferation was inhibited and the integrity of the cell membrane was destroyed; this was further verified using scanning electron microscopy and transmission electron microscopy. In vivo, WL-23 promoted plant growth, increased plant antioxidant enzyme activity, and reduced canker incidence. Therefore, WL-23 is expected to become a biological control agent due to its great potential to contribute to sustainable agriculture.

Comparative transcriptome analysis reveals the core molecular network in pattern-triggered immunity in Sorghum bicolor.

Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is the first line of defense in plant disease resistance. However, the molecular mechanisms of plant PTI vary across species, making it challenging to identify a core set of trait-associated genes. This study aimed to investigate key factors that influence PTI and identify the core molecular network in Sorghum bicolor, a C4 plant. We performed comprehensive weighted gene co-expression network analysis and temporal expression analysis of large-scale transcriptome data from various sorghum cultivars under different PAMP treatments. Our results revealed that the type of PAMP had a stronger influence on the PTI network than did the sorghum cultivar. Following PAMP treatment, 30 genes with stable downregulated expression and 158 genes with stable upregulated expression were identified, including genes encoding potential pattern recognition receptors whose expression was upregulated within 1 h of treatment. PAMP treatment altered the expression of resistance-related, signaling, salt-sensitive, heavy metal-related, and transporter genes. These findings provide novel insights into the core genes involved in plant PTI and are expected to facilitate the identification and application of resistance genes in plant breeding studies.

Efficacy and safety of janagliflozin monotherapy in Chinese patients with type 2 diabetes mellitus inadequately controlled on diet and exercise: A multicentre, randomized, double-blind, placebo-controlled, Phase 3 trial.

AIMS: To evaluate the efficacy and safety of janagliflozin, a selective renal sodium-glucose cotransporter-2 inhibitor, as monotherapy in drug-naive Chinese patients with type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: This Phase 3 trial included a 24-week, multicentre, randomized, double-blind, placebo-controlled period, followed by a 28-week extension period. A total of 432 patients with glycated haemoglobin (HbA1c) levels ≥7.0% (53 mmol/mol) and ≤10.5% (91 mmol/mol) were randomized (1:1:1) to receive once-daily placebo, 25 mg or 50 mg janagliflozin. After 24 weeks, patients on placebo were switched and re-randomized (1:1) to 25 mg or 50 mg janagliflozin, whereas patients on janagliflozin maintained the initial therapy. The primary endpoint was change from baseline in HbA1c after 24 weeks. RESULTS: At Week 24, the placebo-adjusted least squares mean changes in HbA1c were -0.80% (95% confidence interval [CI] -0.98% to -0.62%)/-8.7 mmol/mol (95% CI -10.7 mmol/mol to -6.8 mmol/mol) and -0.88% (95% CI -1.06% to -0.70%)/-9.6 mmol/mol (95% CI -11.6 mmol/mol to -7.7 mmol/mol), respectively (P < 0.001 for both). A higher proportion of patients achieved HbA1c <7.0% (53 mmol/mol) with janagliflozin 25 mg and janagliflozin 50 mg compared with placebo (47.2%, 49.3%, and 23.5%, respectively). Both janagliflozin doses significantly decreased fasting plasma glucose, 2-hour postprandial glucose, body weight and systolic blood pressure, as well as increased high-density lipoprotein (HDL) cholesterol and insulin sensitivity compared with placebo (P < 0.05 for all). The trends in improvement of these variables were sustained during the 28-week extension period. Overall incidences of adverse events were 67.8%, 71.5% and 60.7% with janagliflozin 25 mg, janagliflozin 50 mg and placebo, respectively. The incidence of urinary tract infections and genital fungal infections was low. No severe hypoglycaemia or ketoacidosis occurred. CONCLUSIONS: Janagliflozin 25 mg and 50 mg monotherapy once-daily effectively improved glycaemic control, reduced body weight and blood pressure, improved HDL cholesterol and insulin sensitivity, and was generally well tolerated.

Efficacy and safety of janagliflozin as add-on therapy to metformin in Chinese patients with type 2 diabetes inadequately controlled with metformin alone: A multicentre, randomized, double-blind, placebo-controlled, phase 3 trial.

AIM: To evaluate the efficacy and safety of janagliflozin in Chinese patients with type 2 diabetes (T2D) inadequately controlled with metformin monotherapy. MATERIALS AND METHODS: This multicentre phase 3 trial included a 24-week, randomized, double-blind, placebo-controlled period, followed by a 28-week extension period. Patients (N = 421) with HbA1c of 7.0% or higher and 10.5% or less were randomized (1:1:1) to receive once-daily placebo, janagliflozin 25 or 50 mg. After the 24-week treatment period, patients on placebo were re-randomized (1:1) to janagliflozin 25 or 50 mg for the additional 28-week treatment, whereas patients on janagliflozin maintained the same therapy. The primary endpoint was the change from baseline in HbA1c to week 24. RESULTS: At week 24, the placebo-adjusted least squares mean changes of HbA1c were -0.58% and -0.58% with janagliflozin 25 and 50 mg, respectively (P < .0001 for both). The proportion of patients achieving HbA1c less than 7.0% was higher with janagliflozin 25 and 50 mg compared with placebo (41.8%, 41.7% and 28.0%, respectively). Both janagliflozin doses provided significant reductions in fasting plasma glucose, 2-hour postprandial glucose, body weight and systolic blood pressure, and improvements in high-density lipoprotein cholesterol and insulin sensitivity compared with placebo (P < .05 for all). The trends in improvement of these variables were retained during the 28-week extension period. No severe hypoglycaemia occurred throughout the whole 52-week treatment. CONCLUSIONS: Janagliflozin 25 or 50 mg once-daily added to metformin therapy significantly improved glycaemic control, reduced body weight and systolic blood pressure, improved high-density lipoprotein cholesterol and insulin sensitivity, and was generally well-tolerated by Chinese T2D patients who had poor glycaemic control with metformin monotherapy.

Value Analysis of Using Urinary Microalbumin in Artificial Intelligence Medical Institutions to Detect Early Renal Damage in Diabetes.

As the scale and depth of artificial intelligence network models continue to increase, their accuracy in albumin recognition tasks has increased rapidly. However, today's small medical datasets are the main reason for the poor recognition of artificial intelligence techniques in this area. The sample size in this article is based on the data analysis and research on urine albumin detection of diabetes in the EI database. It is assumed that the observation group has at least 20 mg UAER difference from the control group, and the standard deviation of the UAER change from baseline to 12 weeks is 30 mg. Therefore, the sample size of the two groups is 77 cases. Assuming that the rate of loss to follow-up during the follow-up period is 20%, at least 92 patients are needed. The final enrollment in this study is 100 patients. Studies have shown that DR is used as an indicator to diagnose NDRD, and its OR value is as high as 28.198, indicating that non-DR can be used as an indicator to distinguish DN from NDRD. The meta-analysis found that DR has a sensitivity of 0.65 and a specificity of 0.75 in distinguishing DN from NDRD in patients with type 2 diabetes, and it is emphasized that PDR is highly specific in the diagnosis of DN. Using a meta-analysis to systematically analyze 45 studies, it was found that the sensitivity of DR to diagnose DN was 0.67, the specificity was 0.78, and the specificity of PDR to predict DN was 0.99, indicating that DR is a good indicator for predicting DN, and the team's latest research has also verified this point of view. They have established a new model for diagnosing DN. In addition to including traditional proteinuria, glycosylated hemoglobin, FR, blood pressure, and other indicators into the diagnostic model, it will also include the presence or absence of DR. The final external verification accuracy rate of this model is 0.875.

A Spatial-Temporal Interpretable Deep Learning Model for improving interpretability and predictive accuracy of satellite-based PM2.5.

Being able to monitor PM2.5 across a range of scales is incredibly important for our ability to understand and counteract air pollution. Remote monitoring PM2.5 using satellite-based data would be incredibly advantageous to this effort, but current machine learning methods lack necessary interpretability and predictive accuracy. This study details the development of a new Spatial-Temporal Interpretable Deep Learning Model (SIDLM) to improve the interpretability and predictive accuracy of satellite-based PM2.5 measurements. In contrast to traditional deep learning models, the SIDLM is both "wide" and "deep." We comprehensively evaluated the proposed model in China using different input data (top-of-atmosphere (TOA) measurements-based and aerosol optical depth (AOD)-based, with or without meteorological data) and different spatial resolutions (10 km, 3 km, and 250 m). TOA-based SIDLM PM2.5 achieved the best predictive accuracy in China, with root-mean-square errors (RMSE) of 15.30 and 15.96 µg/m3, and R2 values of 0.70 and 0.66 for PM2.5 predictions at 10 km and 3 km spatial resolutions, respectively. Additionally, we tested the SIDLM in PM2.5 retrievals at a 250 m spatial resolution over Beijing, China (RMSE = 16.01 µg/m3, R2 = 0.62). Furthermore, SIDLM demonstrated higher accuracy than five machine learning inversion methods, and also outperformed them regarding feature extraction and the interpretability of its inversion results. In particular, modeling results indicated the strong influence of the Tongzhou district on the principle PM2.5 in the Beijing urban area. SIDLM-extracted temporal characteristics revealed that summer months (June-August) might have contributed less to PM2.5 concentrations, indicating the limited accumulation of PM2.5 in these months. Our study shows that SIDLM could become an important tool for other earth observation data in deep learning-based predictions and spatiotemporal analysis.

Henagliflozin monotherapy in patients with type 2 diabetes inadequately controlled on diet and exercise: A randomized, double-blind, placebo-controlled, phase 3 trial.

AIM: To evaluate henagliflozin, a novel sodium-glucose co-transporter-2 inhibitor, as monotherapy in patients with type 2 diabetes and inadequate glycaemic control with diet and exercise. MATERIALS AND METHODS: This multicentre trial included a 24-week, randomized, double-blind, placebo-controlled period, followed by a 28-week extension period. Four hundred and sixty-eight patients with an HbA1c of 7.0%-10.5% were randomly assigned (1:1:1) to receive once-daily placebo, or 5 or 10 mg henagliflozin. After 24 weeks, patients on placebo were switched to 5 or 10 mg henagliflozin, and patients on henagliflozin maintained the initial therapy. The primary endpoint was the change in HbA1c from baseline after 24 weeks. RESULTS: At Week 24, the placebo-adjusted least squares (LS) mean changes from baseline in HbA1c were -0.91% (95% CI: -1.11% to -0.72%; P < .001) and -0.94% (-1.13% to -0.75%; P < .001) with henagliflozin 5 and 10 mg, respectively; the placebo-adjusted LS mean changes were -1.3 (-1.8 to -0.9) and -1.5 (-2.0 to -1.1) kg in body weight, and -5.1 (-7.2 to -3.0) and -4.4 (-6.5 to -2.3) mmHg in systolic blood pressure (all P < .05). The trends of these improvements were sustained for an additional 28 weeks. Adverse events occurred in 81.0%, 78.9% and 78.9% of patients in the placebo, henagliflozin 5 and 10 mg groups, respectively. No diabetic ketoacidosis or major episodes of hypoglycaemia occurred. CONCLUSIONS: Henagliflozin 5 mg and 10 mg as monotherapy provided effective glycaemic control, reduced body weight and blood pressure, and was generally well tolerated.

Efficacy and safety of DBPR108 monotherapy in patients with type 2 diabetes: a 12-week, randomized, double-blind, placebo-controlled, phase II clinical trial.

Objective: DBPR108, a novel dipeptidyl-peptidase-4 inhibitor, has shown great antihyperglycemic effect in animal models. This study was to evaluate the efficacy and safety of DBPR108 monotherapy in type 2 diabetes mellitus (T2DM).Methods: This was a 12-week, double-blind, placebo-controlled phase II clinical trial. The newly diagnosed or inadequately controlled untreated T2DM patients were randomized to receive 50, 100, 200 mg DBPR108 or placebo in a ratio of 1:1:1:1. The primary efficacy outcome was HbA1c change from baseline to week 12. Relevant secondary efficacy parameters and safety were assessed. The clinical trial registration is NCT04124484.Results: Overall, 271 of the 276 randomized patients, who received 50 mg (n = 68), 100 mg (n = 67), 200 mg (n = 69) DBPR108 or placebo (n = 67), were included in full analysis set. At week 12, HbA1c change from baseline was -0.04 ± 0.77 in placebo group, -0.51 ± 0.71, -0.75 ± 0.73, and -0.57 ± 0.78 (%, p < .001 vs. placebo) in 50, 100, and 200 mg DBPR108 groups, respectively. Since week 4, DBPR108 monotherapy resulted in significant improvements in secondary efficacy parameters. At end of 12-week treatment, the goal of HbA1c ≤7% was achieved in 29.85, 58.82, 55.22, and 47.83% of the patients in placebo, 50, 100, and 200 mg DBPR108 groups, respectively. The incidence of adverse events did not show significant difference between DBPR108 and placebo except mild hypoglycemia in DBPR108 200 mg group.Conclusions: The study results support DBPR108 100 mg once daily as the primary dosing regimen for T2DM patients in phase III development program.

Antidiabetic effect of Momordica charantia saponins in rats induced by high-fat diet combined with STZ

Background: The harmful effects of type 2 diabetes mellitus and its complications have become a major global public health problem. In this study, the effects of Momordica charantia saponins (MCS) on lipid metabolism, oxidative stress, and insulin signaling pathway in type 2 diabetic rats were investigated. Results: MCS could attenuate the tendency of weight loss of the model rats. It could also improve glucose tolerance; reduce fasting blood glucose, nonesterified fatty acid, triglyceride, and total cholesterol; and increase the insulin content and insulin sensitivity index of the rats. The activity of superoxide dismutase and catalase increased, and the content of malondialdehyde decreased in the liver and pancreas tissues of rats in MCS-treated groups significantly. In addition, the expression of p-IRS-1 (Y612) and p-Akt (S473) increased, and the expression of p-IRS-1 (S307) decreased in the liver tissues and pancreas tissues of rats in MCS-treated groups significantly. Conclusion: MCS has an antidiabetic effect, which may be related to its improving the lipid metabolism disorder, reducing oxidative stress level, and regulating the insulin signaling pathway.

Phenolic compounds from Origanum vulgare and their antioxidant and antiviral activities.

In the present study, six new phenolic compounds (1-6) along with five known ones were isolated from the ethanol extract of the whole plants of Origanum vulgare. The structures of the new compounds were identified on the basis of extensive spectroscopic analyses (UV, IR, NMR, and HRESIMS) and acid hydrolysis. Twenty-one phenolic compounds isolated from O. vulgare in our previous and present studies were evaluated for their in vitro antioxidant activity using 2,2-diphenyl-1-picryhydrazyl (DPPH) radical-scavenging and ferric-reducing antioxidant power (FRAP) assays; twelve of them including two new compounds exhibited significant antioxidant activity comparable to that of ascorbic acid. In addition, the antiviral effects against respiratory syncytial virus (RSV), Coxsackie virus B3 (CVB3) and herpes simplex virus type 1 (HSV-1) were tested by cytopathic effect (CPE) reduction assay.

A mouse model of inducible liver injury caused by tet-on regulated urokinase for studies of hepatocyte transplantation.

Mouse models of liver injury provide useful tools for studying hepatocyte engraftment and proliferation. A representative model of liver injury is the albumin-urokinase (Alb-uPA) transgenic model, but neonatal lethality hampers its widespread application. To overcome this problem, we generated a transgenic mouse in which transcription of the reverse tetracycline transactivator was (rtTA) driven by the mouse albumin promoter, and backcrossed the rtTA mice onto severe combined immunodeficient (SCID)/bg mice to generate immunodeficient rtTA/SCID mice. We then produced recombinant adenoviruses Ad.TRE-uPA, in which the urokinase was located downstream of the tetracycline response element (TRE). The rtTA/SCID mouse hepatocytes were then infected with Ad.TRE-uPA to establish an inducible liver injury mouse model. In the presence of doxycycline, uPA was exclusively expressed in endogenous hepatocytes and caused extensive liver injury. Enhanced green fluorescent protein-labeled mouse hepatocytes selectively repopulated the rtTA/SCID mouse liver and replaced over 80% of the recipient liver mass after repeated administration of Ad.TRE-uPA. Compared with the original uPA mice, rtTA/SCID mice did not exhibit problems regarding breeding efficiency, and the time window for transplantation was flexible. In addition, we could control the extent of liver injury to facilitate transplantation surgery by regulating the dose of Ad.TRE-uPA. Our inducible mouse model will be convenient for studies of hepatocyte transplantation and hepatic regeneration, and this system will facilitate screening for potential genetic factors critical for engraftment and proliferation of hepatocytes in vivo.

Efficient generation of hepatocyte-like cells from human induced pluripotent stem cells.

Human induced pluripotent stem (iPS) cells are similar to embryonic stem (ES) cells, and can proliferate intensively and differentiate into a variety of cell types. However, the hepatic differentiation of human iPS cells has not yet been reported. In this report, human iPS cells were induced to differentiate into hepatic cells by a stepwise protocol. The expression of liver cell markers and liver-related functions of the human iPS cell-derived cells were monitored and compared with that of differentiated human ES cells and primary human hepatocytes. Approximately 60% of the differentiated human iPS cells at day 7 expressed hepatic markers alpha fetoprotein and Alb. The differentiated cells at day 21 exhibited liver cell functions including albumin Asecretion, glycogen synthesis, urea production and inducible cytochrome P450 activity. The expression of hepatic markers and liver-related functions of the iPS cell-derived hepatic cells were comparable to that of the human ES cell-derived hepatic cells. These results show that human iPS cells, which are similar to human ES cells, can be efficiently induced to differentiate into hepatocyte-like cells.

Derivation and characterization of hepatic progenitor cells from human embryonic stem cells.

The derivation of hepatic progenitor cells from human embryonic stem (hES) cells is of value both in the study of early human liver organogenesis and in the creation of an unlimited source of donor cells for hepatocyte transplantation therapy. Here, we report for the first time the generation of hepatic progenitor cells derived from hES cells. Hepatic endoderm cells were generated by activating FGF and BMP pathways and were then purified by fluorescence activated cell sorting using a newly identified surface marker, N-cadherin. After co-culture with STO feeder cells, these purified hepatic endoderm cells yielded hepatic progenitor colonies, which possessed the proliferation potential to be cultured for an extended period of more than 100 days. With extensive expansion, they co-expressed the hepatic marker AFP and the biliary lineage marker KRT7 and maintained bipotential differentiation capacity. They were able to differentiate into hepatocyte-like cells, which expressed ALB and AAT, and into cholangiocyte-like cells, which formed duct-like cyst structures, expressed KRT19 and KRT7, and acquired epithelial polarity. In conclusion, this is the first report of the generation of proliferative and bipotential hepatic progenitor cells from hES cells. These hES cell-derived hepatic progenitor cells could be effectively used as an in vitro model for studying the mechanisms of hepatic stem/progenitor cell origin, self-renewal and differentiation.

Directed differentiation of human embryonic stem cells into functional hepatic cells.

UNLABELLED: The differentiation capacity of human embryonic stem cells (hESCs) holds great promise for therapeutic applications. We report a novel three-stage method to efficiently direct the differentiation of human embryonic stem cells into hepatic cells in serum-free medium. Human ESCs were first differentiated into definitive endoderm cells by 3 days of Activin A treatment. Next, the presence of fibroblast growth factor-4 and bone morphogenetic protein-2 in the culture medium for 5 days induced efficient hepatic differentiation from definitive endoderm cells. Approximately 70% of the cells expressed the hepatic marker albumin. After 10 days of further in vitro maturation, these cells expressed the adult liver cell markers tyrosine aminotransferase, tryptophan oxygenase 2, phosphoenolpyruvate carboxykinase (PEPCK), Cyp7A1, Cyp3A4 and Cyp2B6. Furthermore, these cells exhibited functions associated with mature hepatocytes including albumin secretion, glycogen storage, indocyanine green, and low-density lipoprotein uptake, and inducible cytochrome P450 activity. When transplanted into CCl4 injured severe combined immunodeficiency mice, these cells integrated into the mouse liver and expressed human alpha-1 antitrypsin for at least 2 months. In addition, we found that the hESC-derived hepatic cells were readily infected by human immunodeficiency virus-hepatitis C virus pseudotype viruses. CONCLUSION: We have developed an efficient way to direct the differentiation of human embryonic stem cells into cells that exhibit characteristics of mature hepatocytes. Our studies should facilitate searching the molecular mechanisms underlying human liver development, and form the basis for hepatocyte transplantation and drug tests.

Identification and characterization of label-retaining cells in mouse pancreas.

Pancreatic stem cells (PSCs) may play an important role in maintaining and repairing pancreatic tissues. However, both the existence and localization of PSCs in adult mammalian pancreas still remain elusive. In order to locate the potential pancreatic progenitor/stem cells, we used the tracing label-retaining cells (LRCs) method and identified slow-cycling cells in mouse pancreas. Characterization of the LRCs revealed that the differentiation marker-negative LRCs were located not only within and around the islets but also around the acini and ducts. About 30% of the LRCs around the acini and ducts expressed c-Met, which is a putative pancreatic progenitor/stem cell marker. Moreover, the LRCs around the acini could be activated to form duct-like structures in response to pancreatic damage, and the involvement of these LRCs in the neogenesis of islets and focal areas could also be observed in acini. Our data suggest that the LRCs located around the acini and ducts may represent potential pancreatic progenitor/stem cells, and characterization of these cells may aid in further identification of the specific markers of pancreatic progenitor/stem cells.