Inflammatory Cytokine TNFα Promotes the Long-Term Expansion of Primary Hepatocytes in 3D Culture.

In the healthy adult liver, most hepatocytes proliferate minimally. However, upon physical or chemical injury to the liver, hepatocytes proliferate extensively in vivo under the direction of multiple extracellular cues, including Wnt and pro-inflammatory signals. Currently, liver organoids can be generated readily in vitro from bile-duct epithelial cells, but not hepatocytes. Here, we show that TNFα, an injury-induced inflammatory cytokine, promotes the expansion of hepatocytes in 3D culture and enables serial passaging and long-term culture for more than 6 months. Single-cell RNA sequencing reveals broad expression of hepatocyte markers. Strikingly, in vitro-expanded hepatocytes engrafted, and significantly repopulated, the injured livers of Fah-/- mice. We anticipate that tissue repair signals can be harnessed to promote the expansion of otherwise hard-to-culture cell-types, with broad implications.

Wnt signaling regulates hepatocyte cell division by a transcriptional repressor cascade.

Cell proliferation is tightly controlled by inhibitors that block cell cycle progression until growth signals relieve this inhibition, allowing cells to divide. In several tissues, including the liver, cell proliferation is inhibited at mitosis by the transcriptional repressors E2F7 and E2F8, leading to formation of polyploid cells. Whether growth factors promote mitosis and cell cycle progression by relieving the E2F7/E2F8-mediated inhibition is unknown. We report here on a mechanism of cell division control in the postnatal liver, in which Wnt/ß-catenin signaling maintains active hepatocyte cell division through Tbx3, a Wnt target gene. The TBX3 protein directly represses transcription of E2f7 and E2f8, thereby promoting mitosis. This cascade of sequential transcriptional repressors, initiated by Wnt signals, provides a paradigm for exploring how commonly active developmental signals impact cell cycle completion.

AI support for accurate and fast radiological diagnosis of COVID-19: an international multicenter, multivendor CT study.

OBJECTIVES: Differentiation between COVID-19 and community-acquired pneumonia (CAP) in computed tomography (CT) is a task that can be performed by human radiologists and artificial intelligence (AI). The present study aims to (1) develop an AI algorithm for differentiating COVID-19 from CAP and (2) evaluate its performance. (3) Evaluate the benefit of using the AI result as assistance for radiological diagnosis and the impact on relevant parameters such as accuracy of the diagnosis, diagnostic time, and confidence. METHODS: We included n = 1591 multicenter, multivendor chest CT scans and divided them into AI training and validation datasets to develop an AI algorithm (n = 991 CT scans; n = 462 COVID-19, and n = 529 CAP) from three centers in China. An independent Chinese and German test dataset of n = 600 CT scans from six centers (COVID-19 / CAP; n = 300 each) was used to test the performance of eight blinded radiologists and the AI algorithm. A subtest dataset (180 CT scans; n = 90 each) was used to evaluate the radiologists' performance without and with AI assistance to quantify changes in diagnostic accuracy, reporting time, and diagnostic confidence. RESULTS: The diagnostic accuracy of the AI algorithm in the Chinese-German test dataset was 76.5%. Without AI assistance, the eight radiologists' diagnostic accuracy was 79.1% and increased with AI assistance to 81.5%, going along with significantly shorter decision times and higher confidence scores. CONCLUSION: This large multicenter study demonstrates that AI assistance in CT-based differentiation of COVID-19 and CAP increases radiological performance with higher accuracy and specificity, faster diagnostic time, and improved diagnostic confidence. KEY POINTS: • AI can help radiologists to get higher diagnostic accuracy, make faster decisions, and improve diagnostic confidence. • The China-German multicenter study demonstrates the advantages of a human-machine interaction using AI in clinical radiology for diagnostic differentiation between COVID-19 and CAP in CT scans.

The c-di-GMP signalling component YfiR regulates multiple bacterial phenotypes and virulence in Pseudomonas plecoglossicida.

AIMS: Pseudomonas plecoglossicida (P. plecoglossicida) is the causative agent of visceral granulomas disease in large yellow croaker (Larimichthys crocea) and it causes severe economic loss to its industry. Biofilm formation, related to intracellular cyclic bis (3'-5') diguanylic acid (c-di-GMP) levels, is essential for the lifestyle of P. plecoglossicida. This research aims to investigate the role of YfiR-a key regulator of the diguanylate cyclase YfiN to regulate c-di-GMP levels and reveal its regulatory function of bacterial virulence expression in P. plecoglossicida. METHODS AND RESULTS: A genetic analysis was carried out to identify the yfiBNR operon for c-di-GMP regulation in P. plecoglossicida. Then, we constructed a yfiR mutant and observed increased c-di-GMP levels, enhanced biofilm formation, increased exopolysaccharides, and diminished swimming and swarming motility in this strain. Moreover, through establishing a yolk sac microinjection infection model in zebrafish larvae, an attenuated phenotype of yfiR mutant that manifested as restored survival and lower bacterial colonization was found. CONCLUSIONS: YfiR is the key regulator of virulence in P. plecoglossicida, which contributes to c-di-GMP level, biofilm formation, exopolysaccharides production, swimming, swarming motility, and bacterial colonization in zebrafish model.

Assembly of Poly(ethylene glycol)ylated Oleanolic Acid on a Linear Polymer as a Pseudomucin for Influenza Virus Inhibition and Adsorption.

Biomimicry of the mucin barrier function is an efficient strategy to counteract influenza. We report the simple aminolyzation of poly(methyl vinyl ether-alt-maleic anhydride) (PM) using amine-terminated poly(ethylene glycol)ylated oleanolic acid (OAPEG) to mimic the mucin structure and its adsorption of the influenza virus. Direct interactions between influenza hemagglutinin (HA) and the prepared macromolecule evaluated by surface plasmon resonance and isothermal titration calorimetry demonstrated that the multivalent presentation of OAPEG on PM enhanced the binding affinity to HA with a decrease in KD of approximately three orders of magnitude compared with monomeric OAPEG. Moreover, hemagglutination inhibition assay, viral growth inhibition assay, and cytopathic effect reduction assay indicated that the nonglycosylated polymer could mimic natural heavily glycosylated mucin and thus promote the attachment of the virus in a subnanomolar range. Further investigation of the antiviral effects via time-of-addition assay, dynamic light scattering experiments, and transmission electron microscopy photographs indicated that the pseudomucin could adsorb the virion particles and synergistically inhibit the early attachment and final release steps of the influenza infection cycle. These findings demonstrate the effectiveness of the macromolecule in the physical sequestration and prevention of viral infection. Notably, due to its structural similarities with mucin, the biomacropolymer also has the potential for the rational design of antiviral drugs, influenza adsorbents, or filtration materials and the construction of model systems to explore protection against other pathogenic viruses.

Tissue Repair in the Mouse Liver Following Acute Carbon Tetrachloride Depends on Injury-Induced Wnt/ß-Catenin Signaling.

In the liver, Wnt/ß-catenin signaling is involved in regulating zonation and hepatocyte proliferation during homeostasis. We examined Wnt gene expression and signaling after injury, and we show by in situ hybridization that Wnts are activated by acute carbon tetrachloride (CCl4 ) toxicity. Following injury, peri-injury hepatocytes become Wnt-responsive, expressing the Wnt target gene axis inhibition protein 2 (Axin2). Lineage tracing of peri-injury Axin2+ hepatocytes shows that during recovery the injured parenchyma becomes repopulated and repaired by Axin2+ descendants. Using single-cell RNA sequencing, we show that endothelial cells are the major source of Wnts following acute CCl4 toxicity. Induced loss of ß-catenin in peri-injury hepatocytes results in delayed repair and ultimately injury-induced lethality, while loss of Wnt production from endothelial cells leads to a delay in the proliferative response after injury. Conclusion: Our findings highlight the importance of the Wnt/ß-catenin signaling pathway in restoring tissue integrity following acute liver toxicity and establish a role of endothelial cells as an important Wnt-producing regulator of liver tissue repair following localized liver injury.

Clinical features of COVID-19 convalescent patients with re-positive nucleic acid detection.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a pandemic that has rapidly spread worldwide. Increasingly, confirmed patients being discharged according to the current diagnosis and treatment protocols, follow-up of convalescent patients is important to knowing about the outcome. METHODS: A retrospective study was performed among 98 convalescent patients with COVID-19 in a single medical center. The clinical features of patients during their hospitalization and 2-week postdischarge quarantine were collected. RESULTS: Among the 98 COVID-19 convalescent patients, 17 (17.3%) were detected positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid during 2-week postdischarge quarantine. The median time from discharge to SARS-CoV-2 nucleic acid re-positive was 4 days (IQR, 3-8.5).The median time from symptoms onset to final respiratory SARS-CoV-2 detection of negative result was significantly longer in re-positive group (34 days [IQR, 29.5-42.5]) than in non-re-positive group (19 days [IQR, 16-26]). On the other hand, the levels of CD3-CD56 + NK cells during hospitalization and 2-week postdischarge were higher in re-positive group than in non-re-positive group (repeated measures ANOVA, P = .018). However, only one case in re-positive group showed exudative lesion recurrence in pulmonary computed tomography (CT) with recurred symptoms. CONCLUSION: It is still possible for convalescent patients to show positive for SARS-CoV-2 nucleic acid detection, but most of the re-positive patients showed no deterioration in pulmonary CT findings. Continuous quarantine and close follow-up for convalescent patients are necessary to prevent possible relapse and spread of the disease to some extent.

Advances in molecular imaging of immune checkpoint targets in malignancies: current and future prospect.

OBJECTIVES: This review describes the current status and progress of immune checkpoint targets for imaging of malignancies. Immune checkpoint blockade holds great potential for cancer treatment, and clinical implementation into routine is very rapidly progressing. Therefore, it is an urgent need to become familiar with the vocabulary of immunotherapy and with the evaluation of immune checkpoint and related treatments through noninvasive molecular imaging. Currently, immune target-associated imaging mainly includes PET, SPECT, optical imaging, and MRI. Each imaging method has its own inherent strengths and weaknesses in reflecting tumor morphology and physiology. PD-1, PD-L1, CTLA-4, and LAG-3 are the most commonly considered targets. In this review, the current status and progress of molecular imaging of immune checkpoint targets are discussed. CONCLUSION: Molecular imaging is likely to become a major tool for monitoring immunotherapy. It can help in selecting patients who are suitable for immunotherapy, and also monitor the tumor response. KEY POINTS: • Immune checkpoint blockade holds great promise for the treatment of different malignant tumors. • Molecular imaging can identify the expression of immune checkpoint targets in the tumor microenvironment at the molecular and cellular levels, and therefore helps selecting potential responders, suitable for specific immunotherapy. • Molecular imaging can also monitor immunotherapeutic effects, and therefore participates in the evaluation of tumor response to treatment.

Effect of Copper Foil Crystal Orientation on Graphene Quality Synthesized by Chemical Vapor Deposition.

Line defects such as wrinkles are believed to change the electrical properties of graphene. However, they are often observed in graphene grown via chemical vapor deposition; hence, it is important to study the impact of the substrate condition on graphene quality. In this work, graphene was synthesized on various copper domains with different crystal orientations and surface morphologies. During the synthesis process, three typical crystal orientations were obtained Cu(001), Cu(101), and Cu(111) showing different surface morphologies with various densities of wrinkles. Graphene wrinkles along with copper wrinkles were studied using atomic force microscopy and Kelvin probe force microscopy. The quality of graphene on different crystal orientations and morphologies was evaluated as well. It was found that different crystallographic orientations lead to different degrees of wrinkle and roughness. In addition, these wrinkle defects exhibited characteristic surface potential variations and the density of substrate wrinkles was closely associated with the uniformity of graphene and led to a disordered structure and low crystallinity.

Diagnostic Value of ER, PR, FR and HER-2-Targeted Molecular Probes for Magnetic Resonance Imaging in Patients with Breast Cancer.

BACKGROUND/AIMS: Smart molecular probes are required in the application of Magnetic resonance imaging (MRI) for biochemical and clinical research. This study aims to investigate the diagnostic values of estrogen receptor (ER), progesterone receptor (PR), folate receptor (FR) and human epidermal growth factor receptor 2 (HER-2)-targeted molecular probes in the MRI diagnosis of breast cancer. METHODS: Initially, a total of 508 female breast cancer patients were selected for breast cancer subtype classification by immunohistochemistry. Subsequently, the tumor size, lymph node metastasis, and histological grade of different breast cancer subtypes were compared. Molecular probes of Ab-ER-USPIO, Ab-PR-USPIO, Ab-FR-USPIO and Ab-HER-2-USPIO were constructed and screened. The specific binding of molecular probes to breast cancer cells was detected both in vitro and in vivo by Prussian blue staining and MRI using T1 and T2 weighted images. Finally, in vivo toxicity of Ab-HER-2-USPIO was analyzed using hematoxylin and eosin staining. RESULTS: We identified the following subtypes of breast cancer: Luminal A (ER-positive, FR-positive, HER-2-negative), Luminal B (ER-positive, FR-positive, HER-2-positive), HER-2 overexpression (ER-negative, FR-negative, HER-2-positive), and triple-negative breast cancer (ER-negative, FR-negative, HER-2-negative). Featuring favorable in vitro biocompatibility and low in vivo toxicity, Ab-HER-2-USPIO can specifically bind to breast cancer cells BT47 and SKBR3, thus enhancing the quality of T1 weighted MRI images. CONCLUSION: The results indicate that HER-2-targeted MRI molecular probes may be used in the clinical diagnosis of breast cancer and facilitate the development of promising strategies for breast cancer treatments.

EGFR/Ras Signaling Controls Drosophila Intestinal Stem Cell Proliferation via Capicua-Regulated Genes.

Epithelial renewal in the Drosophila intestine is orchestrated by Intestinal Stem Cells (ISCs). Following damage or stress the intestinal epithelium produces ligands that activate the epidermal growth factor receptor (EGFR) in ISCs. This promotes their growth and division and, thereby, epithelial regeneration. Here we demonstrate that the HMG-box transcriptional repressor, Capicua (Cic), mediates these functions of EGFR signaling. Depleting Cic in ISCs activated them for division, whereas overexpressed Cic inhibited ISC proliferation and midgut regeneration. Epistasis tests showed that Cic acted as an essential downstream effector of EGFR/Ras signaling, and immunofluorescence showed that Cic's nuclear localization was regulated by EGFR signaling. ISC-specific mRNA expression profiling and DNA binding mapping using DamID indicated that Cic represses cell proliferation via direct targets including string (Cdc25), Cyclin E, and the ETS domain transcription factors Ets21C and Pointed (pnt). pnt was required for ISC over-proliferation following Cic depletion, and ectopic pnt restored ISC proliferation even in the presence of overexpressed dominant-active Cic. These studies identify Cic, Pnt, and Ets21C as critical downstream effectors of EGFR signaling in Drosophila ISCs.

[Association of parameters in dynamic contrast-enhanced MRI using reference region model with prognostic factors and molecular subtypes of breast cancer].

OBJECTIVE: To investigate the association of parameters in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using reference region model with prognostic factors and molecular subtypes of breast cancer. METHODS: MRI and pathological data of 50 patients with pathologically confirmed invasive ductal carcinoma of the breast were retrospectively analyzed. Reference region model was applied to analyze pharmacokinetic quantitative parameters including volume transfer constant (RR Ktrans), rate constant (Kep) and the ratio of Ktrans to extracellular space volume (Ktrans/Ve). The associations of the above parameters with prognostic factors and molecular subtypes of breast cancer were analyzed. RESULTS: RR Ktrans and Kep were significantly higher in patients of histological grade 3 compared with those of histological grade 1 & 2 (all P<0.05); and the patients with estrogen receptor (ER)-negative and/or progesterone receptor (PR)-negative also had higher RR Ktrans and Kep than those with ER-positive or PR-positive (all P<0.05). For immunohistochemistry, RR Ktrans and Kep were significantly higher in triple negative breast cancer compared with luminal type breast cancer (all P<0.05). CONCLUSIONS: High RR Ktrans and Kep are associated with poor prognosis of breast cancer, and which can also be used to distinguish molecular subtypes of breast cancer.

Chemical Amination via Cycloaddition of Graphene for Use in a Glucose Sensor.

Graphene was chemically aminated via cycloaddition. Aziridine-ring linkages were formed by covalently modifying the C-C double bonds in graphene. The aminated graphene presents an enhanced hydrophilicity, the contact angle with water decreases from 80.5 degrees to 58.5 degrees. And the conductivity of aminated graphene exhibits exponential decay as the reaction time increase. If the reaction time is 90 min, the resistance of aminated graphene was increased from -32 Ω to -2744 Ω. Because the amino group has good biocompatibility, the aminated graphene is designed for use as an enzyme sensor platform, such as glucose sensor based on glucose oxidase. The aminated graphene exhibited a good detection response for glucose. The increase in device current is about 12% in 1.2 mg/mL glucose solution.

Fez function is required to maintain the size of the animal plate in the sea urchin embryo.

Partitioning ectoderm precisely into neurogenic and non-neurogenic regions is an essential step for neurogenesis of almost all bilaterian embryos. Although it is widely accepted that antagonism between BMP and its inhibitors primarily sets up the border between these two types of ectoderm, it is unclear how such extracellular, diffusible molecules create a sharp and precise border at the single-cell level. Here, we show that Fez, a zinc finger protein, functions as an intracellular factor attenuating BMP signaling specifically within the neurogenic region at the anterior end of sea urchin embryos, termed the animal plate. When Fez function is blocked, the size of this neurogenic ectoderm becomes smaller than normal. However, this reduction is rescued in Fez morphants simply by blocking BMP2/4 translation, indicating that Fez maintains the size of the animal plate by attenuating BMP2/4 function. Consistent with this, the gradient of BMP activity along the aboral side of the animal plate, as measured by pSmad1/5/8 levels, drops significantly in cells expressing Fez and this steep decline requires Fez function. Our data reveal that this neurogenic ectoderm produces an intrinsic system that attenuates BMP signaling to ensure the establishment of a stable, well-defined neural territory, the animal plate.

Intermittent fasting induces rapid hepatocyte proliferation to restore the hepatostat in the mouse liver.

Nutrient availability fluctuates in most natural populations, forcing organisms to undergo periods of fasting and re-feeding. It is unknown how dietary changes influence liver homeostasis. Here, we show that a switch from ad libitum feeding to intermittent fasting (IF) promotes rapid hepatocyte proliferation. Mechanistically, IF-induced hepatocyte proliferation is driven by the combined action of systemic FGF15 and localized WNT signaling. Hepatocyte proliferation during periods of fasting and re-feeding re-establishes a constant liver-to-body mass ratio, thus maintaining the hepatostat. This study provides the first example of dietary influence on adult hepatocyte proliferation and challenges the widely held view that liver tissue is mostly quiescent unless chemically or mechanically injured.

Assessment of Hepatocyte Ploidy by Flow Cytometry.

Polyploidy is a common and dynamic feature of mature rodent and human hepatocytes. While polyploidization occurs naturally during growth, alterations in the distribution of diploid and polyploid cells in the liver can be indicative of tissue stress or a pathologic state. Here, we describe a method for flow cytometric quantification of ploidy distribution by staining with propidium iodide. We first outline a hepatocyte isolation procedure from mouse liver through a two-step perfusion system for analysis of cellular ploidy. In an alternative approach, we employ a nuclei isolation protocol to assess nuclear ploidy. Finally, we describe how the use of fluorescent cell markers is compatible with these methods and helps retain information on cellular position within the tissue.

EGFR signaling activates intestinal stem cells by promoting mitochondrial biogenesis and ß-oxidation.

EGFR-RAS-ERK signaling promotes growth and proliferation in many cell types, and genetic hyperactivation of RAS-ERK signaling drives many cancers. Yet, despite intensive study of upstream components in EGFR signal transduction, the identities and functions of downstream effectors in the pathway are poorly understood. In Drosophila intestinal stem cells (ISCs), the transcriptional repressor Capicua (Cic) and its targets, the ETS-type transcriptional activators Pointed (pnt) and Ets21C, are essential downstream effectors of mitogenic EGFR signaling. Here, we show that these factors promote EGFR-dependent metabolic changes that increase ISC mass, mitochondrial growth, and mitochondrial activity. Gene target analysis using RNA and DamID sequencing revealed that Pnt and Ets21C directly upregulate not only DNA replication and cell cycle genes but also genes for oxidative phosphorylation, the TCA cycle, and fatty acid beta-oxidation. Metabolite analysis substantiated these metabolic functions. The mitochondrial transcription factor B2 (mtTFB2), a direct target of Pnt, was required and partially sufficient for EGFR-driven ISC growth, mitochondrial biogenesis, and proliferation. MEK-dependent EGF signaling stimulated mitochondrial biogenesis in human RPE-1 cells, indicating the conservation of these metabolic effects. This work illustrates how EGFR signaling alters metabolism to coordinately activate cell growth and cell division.

Isolated Metastasis to Spleen-Stomach Space From Follicular Thyroid Cancer Combined With a Benign Subcutaneous Nodule on 18F-FDG PET/CT and 131I Scintigraphy.

ABSTRACT: A 40-year-old woman with follicular thyroid cancer underwent a systemic PET/CT evaluation before operation and then received total thyroidectomy and radioactive 131I ablation therapy. Posttreatment imaging of 131I whole-body scan with SPECT/CT showed that metastasis on the spleen-stomach space coexists with mimicking subcutaneous metastasis, considering their level of 131I accumulation and morphological changes on PET/CT. However, histopathology confirmed the subcutaneous lesion of fibrous hyperplasia by fine-needle aspiration. This case demonstrates a vital role of SPECT/CT in the diagnosis of metastatic thyroid cancer and mimicking metastasis.

An intelligent T1-T2 switchable MRI contrast agent for the non-invasive identification of vulnerable atherosclerotic plaques.

Unlike stable atherosclerotic plaques, vulnerable plaques are very likely to cause serious cardio-cerebrovascular diseases. Meanwhile, how to non-invasively identify vulnerable plaques at early stages has been an urgent but challenging problem in clinical practices. Here, we propose a macrophage-targeted and in situ stimuli-triggered T1-T2 switchable magnetic resonance imaging (MRI) nanoprobe for the non-invasive diagnosis of vulnerable plaques. Precisely, single-dispersed iron oxide nanoparticles (IONPs) modified with hyaluronic acid (HA), denoted as IONP-HP, show macrophage targetability and T1 MRI enhancement (r2/r1 = 3.415). Triggered by the low pH environment of macrophage lysosomes, the single-dispersed IONP-HP transforms into a cluster analogue, which exhibits T2 MRI enhancement (r2/r1 = 13.326). Furthermore, an in vivo switch of T1-T2 enhancement modes shows that the vulnerable plaques exhibit strong T1 enhancement after intravenous administration of the nanoprobe, followed by a switch to T2 enhancement after 9 h. In contrast, stable plaques show only slight T1 enhancement but without T2 enhancement. It is therefore imperative that the intelligent and novel nanoplatform proposed in this study achieves a substantial non-invasive diagnosis of vulnerable plaques by means of a facile but effective T1-T2 switchable process, which will significantly contribute to the application of materials science in solving clinical problems.

Effect of elasticity on the phagocytosis of micro/nanoparticles.

A broad range of investigation methods and frameworks are currently used to throughly study the elasticity of various types of micro/nanoparticles (MNPs) with different properties and to explore the effect of such properties on their interactions with biological species. Specifically, the elasticity of MNPs serves as a key influencing factor with respect to important aspects of phagocytosis, such as the clathrin-mediated phagocytosis, caveolae-mediated phagocytosis, macropinocytosis, and cell membrane fusion. Achieving a clear understanding of the relationships that exist between the elasticity of MNPs and their phagocytic processes is essential to improve their performance in drug delivery, which is related to aspects such as circulation lifetime in blood, accumulation time in tissues, and resistance to metabolism. Resolving such aspects is very challenging, and related efforts require using the right tools/methods, which are not always easy to identify. This review aims to facilitate this by summarizing and comparing different cell phagocytosis pathways, while considering various MNPs exhibiting different elastic properties, shape change capabilities, and their effect on cellular uptake. We conduct an overview of the advantages exhibited by different MNPs with respect to both in vitro and in vivo delivery, taking computational simulation analysis and experimental results into account. This study will provide a guide for how to investigate various types of MNPs in terms of their elastic properties, together with their biomedical effects that rely on phagocytosis.